--- _id: '26' abstract: - lang: eng text: Expression of genes is a fundamental molecular phenotype that is subject to evolution by different types of mutations. Both the rate and the effect of mutations may depend on the DNA sequence context of a particular gene or a particular promoter sequence. In this thesis I investigate the nature of this dependence using simple genetic systems in Escherichia coli. With these systems I explore the evolution of constitutive gene expression from random starting sequences at different loci on the chromosome and at different locations in sequence space. First, I dissect chromosomal neighborhood effects that underlie locus-dependent differences in the potential of a gene under selection to become more highly expressed. Next, I find that the effects of point mutations in promoter sequences are dependent on sequence context, and that an existing energy matrix model performs poorly in predicting relative expression of unrelated sequences. Finally, I show that a substantial fraction of random sequences contain functional promoters and I present an extended thermodynamic model that predicts promoter strength in full sequence space. Taken together, these results provide new insights and guides on how to integrate information on sequence context to improve our qualitative and quantitative understanding of bacterial gene expression, with implications for rapid evolution of drug resistance, de novo evolution of genes, and horizontal gene transfer. alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Magdalena full_name: Steinrück, Magdalena id: 2C023F40-F248-11E8-B48F-1D18A9856A87 last_name: Steinrück orcid: 0000-0003-1229-9719 citation: ama: Steinrück M. The influence of sequence context on the evolution of bacterial gene expression. 2018. doi:10.15479/AT:ISTA:th1059 apa: Steinrück, M. (2018). The influence of sequence context on the evolution of bacterial gene expression. Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:th1059 chicago: Steinrück, Magdalena. “The Influence of Sequence Context on the Evolution of Bacterial Gene Expression.” Institute of Science and Technology Austria, 2018. https://doi.org/10.15479/AT:ISTA:th1059. ieee: M. Steinrück, “The influence of sequence context on the evolution of bacterial gene expression,” Institute of Science and Technology Austria, 2018. ista: Steinrück M. 2018. The influence of sequence context on the evolution of bacterial gene expression. Institute of Science and Technology Austria. mla: Steinrück, Magdalena. The Influence of Sequence Context on the Evolution of Bacterial Gene Expression. Institute of Science and Technology Austria, 2018, doi:10.15479/AT:ISTA:th1059. short: M. Steinrück, The Influence of Sequence Context on the Evolution of Bacterial Gene Expression, Institute of Science and Technology Austria, 2018. date_created: 2018-12-11T11:44:14Z date_published: 2018-10-30T00:00:00Z date_updated: 2023-09-07T12:48:43Z day: '30' ddc: - '576' - '579' degree_awarded: PhD department: - _id: CaGu doi: 10.15479/AT:ISTA:th1059 file: - access_level: closed checksum: 413cbce1cd1debeae3abe2a25dbc70d1 content_type: application/vnd.openxmlformats-officedocument.wordprocessingml.document creator: dernst date_created: 2019-02-08T10:51:22Z date_updated: 2020-07-14T12:45:43Z embargo_to: open_access file_id: '5941' file_name: Thesis_Steinrueck_final.docx file_size: 9190845 relation: source_file - access_level: open_access checksum: 3def8b7854c8b42d643597ce0215efac content_type: application/pdf creator: dernst date_created: 2019-02-08T10:51:22Z date_updated: 2021-02-11T11:17:14Z embargo: 2019-11-02 file_id: '5942' file_name: Thesis_Steinrueck_final.pdf file_size: 7521973 relation: main_file file_date_updated: 2021-02-11T11:17:14Z has_accepted_license: '1' language: - iso: eng month: '10' oa: 1 oa_version: Published Version page: '109' publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '8029' pubrep_id: '1059' related_material: record: - id: '704' relation: part_of_dissertation status: public status: public supervisor: - first_name: Calin C full_name: Guet, Calin C id: 47F8433E-F248-11E8-B48F-1D18A9856A87 last_name: Guet orcid: 0000-0001-6220-2052 title: The influence of sequence context on the evolution of bacterial gene expression type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2018' ... --- _id: '6263' abstract: - lang: eng text: 'Antibiotic resistance can emerge spontaneously through genomic mutation and render treatment ineffective. To counteract this process, in addition to the discovery and description of resistance mechanisms,a deeper understanding of resistanceevolvabilityand its determinantsis needed. To address this challenge, this thesisuncoversnew genetic determinants of resistance evolvability using a customized robotic setup, exploressystematic ways in which resistance evolution is perturbed due to dose-responsecharacteristics of drugs and mutation rate differences,and mathematically investigates the evolutionary fate of one specific type of evolvability modifier -a stress-induced mutagenesis allele.We find severalgenes which strongly inhibit or potentiate resistance evolution. In order to identify them, we first developedan automated high-throughput feedback-controlled protocol whichkeeps the population size and selection pressure approximately constant for hundreds of cultures by dynamically re-diluting the cultures and adjusting the antibiotic concentration. We implementedthis protocol on a customized liquid handling robot and propagated 100 different gene deletion strains of Escherichia coliin triplicate for over 100 generations in tetracycline and in chloramphenicol, and comparedtheir adaptation rates.We find a diminishing returns pattern, where initially sensitive strains adapted more compared to less sensitive ones. Our data uncover that deletions of certain genes which do not affect mutation rate,including efflux pump components, a chaperone and severalstructural and regulatory genes can strongly and reproducibly alterresistance evolution. Sequencing analysis of evolved populations indicates that epistasis with resistance mutations is the most likelyexplanation. This work could inspire treatment strategies in which targeted inhibitors of evolvability mechanisms will be given alongside antibiotics to slow down resistance evolution and extend theefficacy of antibiotics.We implemented astochasticpopulation genetics model, toverifyways in which general properties, namely, dose-response characteristics of drugs and mutation rates, influence evolutionary dynamics. In particular, under the exposure to antibiotics with shallow dose-response curves,bacteria have narrower distributions of fitness effects of new mutations. We show that in silicothis also leads to slower resistance evolution. We see and confirm with experiments that increased mutation rates, apart from speeding up evolution, also leadto high reproducibility of phenotypic adaptation in a context of continually strong selection pressure.Knowledge of these patterns can aid in predicting the dynamics of antibiotic resistance evolutionand adapting treatment schemes accordingly.Focusing on a previously described type of evolvability modifier –a stress-induced mutagenesis allele –we find conditions under which it can persist in a population under periodic selectionakin to clinical treatment. We set up a deterministic infinite populationcontinuous time model tracking the frequencies of a mutator and resistance allele and evaluate various treatment schemes in how well they maintain a stress-induced mutator allele. In particular,a high diversity of stresses is crucial for the persistence of the mutator allele. This leads to a general trade-off where exactly those diversifying treatment schemes which are likely to decrease levels of resistance could lead to stronger selection of highly evolvable genotypes.In the long run, this work will lead to a deeper understanding of the genetic and cellular mechanisms involved in antibiotic resistance evolution and could inspire new strategies for slowing down its rate. ' acknowledged_ssus: - _id: M-Shop - _id: LifeSc alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Marta full_name: Lukacisinova, Marta id: 4342E402-F248-11E8-B48F-1D18A9856A87 last_name: Lukacisinova orcid: 0000-0002-2519-8004 citation: ama: Lukacisinova M. Genetic determinants of antibiotic resistance evolution. 2018. doi:10.15479/AT:ISTA:th1072 apa: Lukacisinova, M. (2018). Genetic determinants of antibiotic resistance evolution. Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:th1072 chicago: Lukacisinova, Marta. “Genetic Determinants of Antibiotic Resistance Evolution.” Institute of Science and Technology Austria, 2018. https://doi.org/10.15479/AT:ISTA:th1072. ieee: M. Lukacisinova, “Genetic determinants of antibiotic resistance evolution,” Institute of Science and Technology Austria, 2018. ista: Lukacisinova M. 2018. Genetic determinants of antibiotic resistance evolution. Institute of Science and Technology Austria. mla: Lukacisinova, Marta. Genetic Determinants of Antibiotic Resistance Evolution. Institute of Science and Technology Austria, 2018, doi:10.15479/AT:ISTA:th1072. short: M. Lukacisinova, Genetic Determinants of Antibiotic Resistance Evolution, Institute of Science and Technology Austria, 2018. date_created: 2019-04-09T13:57:15Z date_published: 2018-12-28T00:00:00Z date_updated: 2023-09-22T09:20:37Z day: '28' ddc: - '570' - '576' - '579' degree_awarded: PhD department: - _id: ToBo doi: 10.15479/AT:ISTA:th1072 file: - access_level: open_access checksum: fc60585c9eaad868ac007004ef130908 content_type: application/pdf creator: dernst date_created: 2019-04-09T13:49:24Z date_updated: 2021-02-11T11:17:17Z embargo: 2020-01-25 file_id: '6264' file_name: 2018_Thesis_Lukacisinova.pdf file_size: 5656866 relation: main_file - access_level: closed checksum: 264057ec0a92ab348cc83b41f021ba92 content_type: application/vnd.openxmlformats-officedocument.wordprocessingml.document creator: dernst date_created: 2019-04-09T13:49:23Z date_updated: 2020-07-14T12:47:25Z embargo_to: open_access file_id: '6265' file_name: 2018_Thesis_Lukacisinova_source.docx file_size: 5168054 relation: source_file file_date_updated: 2021-02-11T11:17:17Z has_accepted_license: '1' language: - iso: eng month: '12' oa: 1 oa_version: Published Version page: '91' publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria related_material: record: - id: '1619' relation: part_of_dissertation status: public - id: '696' relation: part_of_dissertation status: public - id: '1027' relation: part_of_dissertation status: public status: public supervisor: - first_name: Tobias full_name: Bollenbach, Tobias id: 3E6DB97A-F248-11E8-B48F-1D18A9856A87 last_name: Bollenbach orcid: 0000-0003-4398-476X title: Genetic determinants of antibiotic resistance evolution type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2018' ... --- _id: '1155' abstract: - lang: eng text: This dissertation concerns the automatic verification of probabilistic systems and programs with arrays by statistical and logical methods. Although statistical and logical methods are different in nature, we show that they can be successfully combined for system analysis. In the first part of the dissertation we present a new statistical algorithm for the verification of probabilistic systems with respect to unbounded properties, including linear temporal logic. Our algorithm often performs faster than the previous approaches, and at the same time requires less information about the system. In addition, our method can be generalized to unbounded quantitative properties such as mean-payoff bounds. In the second part, we introduce two techniques for comparing probabilistic systems. Probabilistic systems are typically compared using the notion of equivalence, which requires the systems to have the equal probability of all behaviors. However, this notion is often too strict, since probabilities are typically only empirically estimated, and any imprecision may break the relation between processes. On the one hand, we propose to replace the Boolean notion of equivalence by a quantitative distance of similarity. For this purpose, we introduce a statistical framework for estimating distances between Markov chains based on their simulation runs, and we investigate which distances can be approximated in our framework. On the other hand, we propose to compare systems with respect to a new qualitative logic, which expresses that behaviors occur with probability one or a positive probability. This qualitative analysis is robust with respect to modeling errors and applicable to many domains. In the last part, we present a new quantifier-free logic for integer arrays, which allows us to express counting. Counting properties are prevalent in array-manipulating programs, however they cannot be expressed in the quantified fragments of the theory of arrays. We present a decision procedure for our logic, and provide several complexity results. acknowledgement: ' First of all, I want to thank my advisor, prof. Thomas A. Henzinger, for his guidance during my PhD program. I am grateful for the freedom I was given to pursue my research interests, and his continuous support. Working with prof. Henzinger was a truly inspiring experience and taught me what it means to be a scientist. I want to express my gratitude to my collaborators: Nikola Beneš, Krishnendu Chatterjee, Martin Chmelík, Ashutosh Gupta, Willibald Krenn, Jan Kˇretínský, Dejan Nickovic, Andrey Kupriyanov, and Tatjana Petrov. I have learned a great deal from my collaborators, and without their help this thesis would not be possible. In addition, I want to thank the members of my thesis committee: Dirk Beyer, Dejan Nickovic, and Georg Weissenbacher for their advice and reviewing this dissertation. I would especially like to acknowledge the late Helmut Veith, who was a member of my committee. I will remember Helmut for his kindness, enthusiasm, and wit, as well as for being an inspiring scientist. Finally, I would like to thank my colleagues for making my stay at IST such a pleasant experience: Guy Avni, Sergiy Bogomolov, Ventsislav Chonev, Rasmus Ibsen-Jensen, Mirco Giacobbe, Bernhard Kragl, Hui Kong, Petr Novotný, Jan Otop, Andreas Pavlogiannis, Tantjana Petrov, Arjun Radhakrishna, Jakob Ruess, Thorsten Tarrach, as well as other members of groups Henzinger and Chatterjee. ' alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Przemyslaw full_name: Daca, Przemyslaw id: 49351290-F248-11E8-B48F-1D18A9856A87 last_name: Daca citation: ama: Daca P. Statistical and logical methods for property checking. 2017. doi:10.15479/AT:ISTA:TH_730 apa: Daca, P. (2017). Statistical and logical methods for property checking. Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:TH_730 chicago: Daca, Przemyslaw. “Statistical and Logical Methods for Property Checking.” Institute of Science and Technology Austria, 2017. https://doi.org/10.15479/AT:ISTA:TH_730. ieee: P. Daca, “Statistical and logical methods for property checking,” Institute of Science and Technology Austria, 2017. ista: Daca P. 2017. Statistical and logical methods for property checking. Institute of Science and Technology Austria. mla: Daca, Przemyslaw. Statistical and Logical Methods for Property Checking. Institute of Science and Technology Austria, 2017, doi:10.15479/AT:ISTA:TH_730. short: P. Daca, Statistical and Logical Methods for Property Checking, Institute of Science and Technology Austria, 2017. date_created: 2018-12-11T11:50:27Z date_published: 2017-01-02T00:00:00Z date_updated: 2023-09-07T11:58:34Z day: '02' ddc: - '004' - '005' degree_awarded: PhD department: - _id: ToHe doi: 10.15479/AT:ISTA:TH_730 ec_funded: 1 file: - access_level: open_access checksum: 1406a681cb737508234fde34766be2c2 content_type: application/pdf creator: system date_created: 2018-12-12T10:11:26Z date_updated: 2020-07-14T12:44:34Z file_id: '4880' file_name: IST-2017-730-v1+1_Statistical_and_Logical_Methods_for_Property_Checking.pdf file_size: 1028586 relation: main_file file_date_updated: 2020-07-14T12:44:34Z has_accepted_license: '1' language: - iso: eng month: '01' oa: 1 oa_version: Published Version page: '163' project: - _id: 25EE3708-B435-11E9-9278-68D0E5697425 call_identifier: FP7 grant_number: '267989' name: Quantitative Reactive Modeling - _id: 25F42A32-B435-11E9-9278-68D0E5697425 call_identifier: FWF grant_number: Z211 name: The Wittgenstein Prize - _id: 25832EC2-B435-11E9-9278-68D0E5697425 call_identifier: FWF grant_number: S 11407_N23 name: Rigorous Systems Engineering publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '6203' pubrep_id: '730' related_material: record: - id: '1093' relation: part_of_dissertation status: public - id: '1230' relation: part_of_dissertation status: public - id: '1234' relation: part_of_dissertation status: public - id: '1391' relation: part_of_dissertation status: public - id: '1501' relation: part_of_dissertation status: public - id: '1502' relation: part_of_dissertation status: public - id: '2063' relation: part_of_dissertation status: public - id: '2167' relation: part_of_dissertation status: public status: public supervisor: - first_name: Thomas A full_name: Henzinger, Thomas A id: 40876CD8-F248-11E8-B48F-1D18A9856A87 last_name: Henzinger orcid: 0000−0002−2985−7724 title: Statistical and logical methods for property checking type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2017' ... --- _id: '6291' abstract: - lang: eng text: Bacteria and their pathogens – phages – are the most abundant living entities on Earth. Throughout their coevolution, bacteria have evolved multiple immune systems to overcome the ubiquitous threat from the phages. Although the molecu- lar details of these immune systems’ functions are relatively well understood, their epidemiological consequences for the phage-bacterial communities have been largely neglected. In this thesis we employed both experimental and theoretical methods to explore whether herd and social immunity may arise in bacterial popu- lations. Using our experimental system consisting of Escherichia coli strains with a CRISPR based immunity to the T7 phage we show that herd immunity arises in phage-bacterial communities and that it is accentuated when the populations are spatially structured. By fitting a mathematical model, we inferred expressions for the herd immunity threshold and the velocity of spread of a phage epidemic in partially resistant bacterial populations, which both depend on the bacterial growth rate, phage burst size and phage latent period. We also investigated the poten- tial for social immunity in Streptococcus thermophilus and its phage 2972 using a bioinformatic analysis of potentially coding short open reading frames with a signalling signature, encoded within the CRISPR associated genes. Subsequently, we tested one identified potentially signalling peptide and found that its addition to a phage-challenged culture increases probability of survival of bacteria two fold, although the results were only marginally significant. Together, these results demonstrate that the ubiquitous arms races between bacteria and phages have further consequences at the level of the population. alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Pavel full_name: Payne, Pavel id: 35F78294-F248-11E8-B48F-1D18A9856A87 last_name: Payne orcid: 0000-0002-2711-9453 citation: ama: Payne P. Bacterial herd and social immunity to phages. 2017. apa: Payne, P. (2017). Bacterial herd and social immunity to phages. Institute of Science and Technology Austria. chicago: Payne, Pavel. “Bacterial Herd and Social Immunity to Phages.” Institute of Science and Technology Austria, 2017. ieee: P. Payne, “Bacterial herd and social immunity to phages,” Institute of Science and Technology Austria, 2017. ista: Payne P. 2017. Bacterial herd and social immunity to phages. Institute of Science and Technology Austria. mla: Payne, Pavel. Bacterial Herd and Social Immunity to Phages. Institute of Science and Technology Austria, 2017. short: P. Payne, Bacterial Herd and Social Immunity to Phages, Institute of Science and Technology Austria, 2017. date_created: 2019-04-09T15:16:45Z date_published: 2017-02-01T00:00:00Z date_updated: 2023-09-07T12:00:00Z day: '01' ddc: - '570' degree_awarded: PhD department: - _id: NiBa - _id: JoBo file: - access_level: closed checksum: a0fc5c26a89c0ea759947ffba87d0d8f content_type: application/pdf creator: dernst date_created: 2019-04-09T15:15:32Z date_updated: 2020-07-14T12:47:27Z file_id: '6292' file_name: thesis_pavel_payne_final_w_signature_page.pdf file_size: 3025175 relation: main_file - access_level: open_access checksum: af531e921a7f64a9e0af4cd8783b2226 content_type: application/pdf creator: dernst date_created: 2021-02-22T13:45:59Z date_updated: 2021-02-22T13:45:59Z file_id: '9187' file_name: 2017_Payne_Thesis.pdf file_size: 3111536 relation: main_file success: 1 file_date_updated: 2021-02-22T13:45:59Z has_accepted_license: '1' language: - iso: eng month: '02' oa: 1 oa_version: Published Version page: '83' publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria status: public supervisor: - first_name: Jonathan P full_name: Bollback, Jonathan P id: 2C6FA9CC-F248-11E8-B48F-1D18A9856A87 last_name: Bollback orcid: 0000-0002-4624-4612 - first_name: Nicholas H full_name: Barton, Nicholas H id: 4880FE40-F248-11E8-B48F-1D18A9856A87 last_name: Barton orcid: 0000-0002-8548-5240 title: Bacterial herd and social immunity to phages type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2017' ... --- _id: '818' abstract: - lang: eng text: 'Antibiotics have diverse effects on bacteria, including massive changes in bacterial gene expression. Whereas the gene expression changes under many antibiotics have been measured, the temporal organization of these responses and their dependence on the bacterial growth rate are unclear. As described in Chapter 1, we quantified the temporal gene expression changes in the bacterium Escherichia coli in response to the sudden exposure to antibiotics using a fluorescent reporter library and a robotic system. Our data show temporally structured gene expression responses, with response times for individual genes ranging from tens of minutes to several hours. We observed that many stress response genes were activated in response to antibiotics. As certain stress responses cross-protect bacteria from other stressors, we then asked whether cellular responses to antibiotics have a similar protective role in Chapter 2. Indeed, we found that the trimethoprim-induced acid stress response protects bacteria from subsequent acid stress. We combined microfluidics with time-lapse imaging to monitor survival, intracellular pH, and acid stress response in single cells. This approach revealed that the variable expression of the acid resistance operon gadBC strongly correlates with single-cell survival time. Cells with higher gadBC expression following trimethoprim maintain higher intracellular pH and survive the acid stress longer. Overall, we provide a way to identify single-cell cross-protection between antibiotics and environmental stressors from temporal gene expression data, and show how antibiotics can increase bacterial fitness in changing environments. While gene expression changes to antibiotics show a clear temporal structure at the population-level, it is unclear whether this clear temporal order is followed by every single cell. Using dual-reporter strains described in Chapter 3, we measured gene expression dynamics of promoter pairs in the same cells using microfluidics and microscopy. Chapter 4 shows that the oxidative stress response and the DNA stress response showed little timing variability and a clear temporal order under the antibiotic nitrofurantoin. In contrast, the acid stress response under trimethoprim ran independently from all other activated response programs including the DNA stress response, which showed particularly high timing variability in this stress condition. In summary, this approach provides insight into the temporal organization of gene expression programs at the single-cell level and suggests dependencies between response programs and the underlying variability-introducing mechanisms. Altogether, this work advances our understanding of the diverse effects that antibiotics have on bacteria. These results were obtained by taking into account gene expression dynamics, which allowed us to identify general principles, molecular mechanisms, and dependencies between genes. Our findings may have implications for infectious disease treatments, and microbial communities in the human body and in nature. ' acknowledgement: 'First of all, I would like to express great gratitude to my PhD supervisor Tobias Bollenbach. Through his open and trusting attitude I had the freedom to explore different scientific directions during this project, and follow the research lines of my interest. I am thankful for constructive and often extensive discussions and his support and commitment during the different stages of my PhD. I want to thank my committee members, Călin Guet, Terry Hwa and Nassos Typas for their interest and their valuable input to this project. Special thanks to Nassos for career guidance, and for accepting me in his lab. A big thank you goes to the past, present and affiliated members of the Bollenbach group: Guillaume Chevereau, Marjon de Vos, Marta Lukačišinová, Veronika Bierbaum, Qi Qin, Marcin Zagórski, Martin Lukačišin, Andreas Angermayr, Bor Kavčič, Julia Tischler, Dilay Ayhan, Jaroslav Ferenc, and Georg Rieckh. I enjoyed working and discussing with you very much and I will miss our lengthy group meetings, our inspiring journal clubs, and our common lunches. Special thanks to Bor for great mental and professional support during the hard months of thesis writing, and to Marta for very creative times during the beginning of our PhDs. May the ‘Bacterial Survival Guide’ decorate the walls of IST forever! A great thanks to my friend and collaborator Georg Rieckh for his enthusiasm and for getting so involved in these projects, for his endurance and for his company throughout the years. Thanks to the FriSBi crowd at IST Austria for interesting meetings and discussions. In particular I want to thank Magdalena Steinrück, and Anna Andersson for inspiring exchange, and enjoyable time together. Thanks to everybody who contributed to the cover for Cell Systems: The constructive input from Tobias Bollenbach, Bor Kavčič, Georg Rieckh, Marta Lukačišinová, and Sebastian Nozzi, and the professional implementation by the graphic designer Martina Markus from the University of Cologne. Thanks to all my office mates in the first floor Bertalanffy building throughout the years: for ensuring a pleasant working atmosphere, and for your company! In general, I want to thank all the people that make IST such a great environment, with the many possibilities to shape our own social and research environment. I want to thank my family for all kind of practical support during the years, and my second family in Argentina for their enthusiasm. Thanks to my brother Bernhard and my sister Martina for being great siblings, and to Helena and Valentin for the joy you brought to my life. My deep gratitude goes to Sebastian Nozzi, for constant support, patience, love and for believing in me. ' alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Karin full_name: Mitosch, Karin id: 39B66846-F248-11E8-B48F-1D18A9856A87 last_name: Mitosch citation: ama: Mitosch K. Timing, variability and cross-protection in bacteria – insights from dynamic gene expression responses to antibiotics. 2017. doi:10.15479/AT:ISTA:th_862 apa: Mitosch, K. (2017). Timing, variability and cross-protection in bacteria – insights from dynamic gene expression responses to antibiotics. Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:th_862 chicago: Mitosch, Karin. “Timing, Variability and Cross-Protection in Bacteria – Insights from Dynamic Gene Expression Responses to Antibiotics.” Institute of Science and Technology Austria, 2017. https://doi.org/10.15479/AT:ISTA:th_862. ieee: K. Mitosch, “Timing, variability and cross-protection in bacteria – insights from dynamic gene expression responses to antibiotics,” Institute of Science and Technology Austria, 2017. ista: Mitosch K. 2017. Timing, variability and cross-protection in bacteria – insights from dynamic gene expression responses to antibiotics. Institute of Science and Technology Austria. mla: Mitosch, Karin. Timing, Variability and Cross-Protection in Bacteria – Insights from Dynamic Gene Expression Responses to Antibiotics. Institute of Science and Technology Austria, 2017, doi:10.15479/AT:ISTA:th_862. short: K. Mitosch, Timing, Variability and Cross-Protection in Bacteria – Insights from Dynamic Gene Expression Responses to Antibiotics, Institute of Science and Technology Austria, 2017. date_created: 2018-12-11T11:48:40Z date_published: 2017-09-27T00:00:00Z date_updated: 2023-09-07T12:00:26Z day: '27' ddc: - '571' - '579' degree_awarded: PhD department: - _id: ToBo doi: 10.15479/AT:ISTA:th_862 file: - access_level: closed checksum: da3993c5f90f59a8e8623cc31ad501dd content_type: application/vnd.openxmlformats-officedocument.wordprocessingml.document creator: dernst date_created: 2019-04-05T08:48:51Z date_updated: 2020-07-14T12:48:09Z file_id: '6210' file_name: Thesis_KarinMitosch.docx file_size: 6331071 relation: source_file - access_level: open_access checksum: 24c3d9e51992f1b721f3df55aa13fcb8 content_type: application/pdf creator: dernst date_created: 2019-04-05T08:48:51Z date_updated: 2020-07-14T12:48:09Z file_id: '6211' file_name: Thesis_KarinMitosch.pdf file_size: 9289852 relation: main_file file_date_updated: 2020-07-14T12:48:09Z has_accepted_license: '1' language: - iso: eng license: https://creativecommons.org/licenses/by/4.0/ month: '09' oa: 1 oa_version: Published Version page: '113' publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '6831' pubrep_id: '862' related_material: record: - id: '2001' relation: part_of_dissertation status: public - id: '666' relation: part_of_dissertation status: public status: public supervisor: - first_name: Mark Tobias full_name: Bollenbach, Mark Tobias id: 3E6DB97A-F248-11E8-B48F-1D18A9856A87 last_name: Bollenbach orcid: 0000-0003-4398-476X title: Timing, variability and cross-protection in bacteria – insights from dynamic gene expression responses to antibiotics tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2017' ... --- _id: '821' abstract: - lang: eng text: "This dissertation focuses on algorithmic aspects of program verification, and presents modeling and complexity advances on several problems related to the\r\nstatic analysis of programs, the stateless model checking of concurrent programs, and the competitive analysis of real-time scheduling algorithms.\r\nOur contributions can be broadly grouped into five categories.\r\n\r\nOur first contribution is a set of new algorithms and data structures for the quantitative and data-flow analysis of programs, based on the graph-theoretic notion of treewidth.\r\nIt has been observed that the control-flow graphs of typical programs have special structure, and are characterized as graphs of small treewidth.\r\nWe utilize this structural property to provide faster algorithms for the quantitative and data-flow analysis of recursive and concurrent programs.\r\nIn most cases we make an algebraic treatment of the considered problem,\r\nwhere several interesting analyses, such as the reachability, shortest path, and certain kind of data-flow analysis problems follow as special cases. \r\nWe exploit the constant-treewidth property to obtain algorithmic improvements for on-demand versions of the problems, \r\nand provide data structures with various tradeoffs between the resources spent in the preprocessing and querying phase.\r\nWe also improve on the algorithmic complexity of quantitative problems outside the algebraic path framework,\r\nnamely of the minimum mean-payoff, minimum ratio, and minimum initial credit for energy problems.\r\n\r\n\r\nOur second contribution is a set of algorithms for Dyck reachability with applications to data-dependence analysis and alias analysis.\r\nIn particular, we develop an optimal algorithm for Dyck reachability on bidirected graphs, which are ubiquitous in context-insensitive, field-sensitive points-to analysis.\r\nAdditionally, we develop an efficient algorithm for context-sensitive data-dependence analysis via Dyck reachability,\r\nwhere the task is to obtain analysis summaries of library code in the presence of callbacks.\r\nOur algorithm preprocesses libraries in almost linear time, after which the contribution of the library in the complexity of the client analysis is (i)~linear in the number of call sites and (ii)~only logarithmic in the size of the whole library, as opposed to linear in the size of the whole library.\r\nFinally, we prove that Dyck reachability is Boolean Matrix Multiplication-hard in general, and the hardness also holds for graphs of constant treewidth.\r\nThis hardness result strongly indicates that there exist no combinatorial algorithms for Dyck reachability with truly subcubic complexity.\r\n\r\n\r\nOur third contribution is the formalization and algorithmic treatment of the Quantitative Interprocedural Analysis framework.\r\nIn this framework, the transitions of a recursive program are annotated as good, bad or neutral, and receive a weight which measures\r\nthe magnitude of their respective effect.\r\nThe Quantitative Interprocedural Analysis problem asks to determine whether there exists an infinite run of the program where the long-run ratio of the bad weights over the good weights is above a given threshold.\r\nWe illustrate how several quantitative problems related to static analysis of recursive programs can be instantiated in this framework,\r\nand present some case studies to this direction.\r\n\r\n\r\nOur fourth contribution is a new dynamic partial-order reduction for the stateless model checking of concurrent programs. Traditional approaches rely on the standard Mazurkiewicz equivalence between traces, by means of partitioning the trace space into equivalence classes, and attempting to explore a few representatives from each class.\r\nWe present a new dynamic partial-order reduction method called the Data-centric Partial Order Reduction (DC-DPOR).\r\nOur algorithm is based on a new equivalence between traces, called the observation equivalence.\r\nDC-DPOR explores a coarser partitioning of the trace space than any exploration method based on the standard Mazurkiewicz equivalence.\r\nDepending on the program, the new partitioning can be even exponentially coarser.\r\nAdditionally, DC-DPOR spends only polynomial time in each explored class.\r\n\r\n\r\nOur fifth contribution is the use of automata and game-theoretic verification techniques in the competitive analysis and synthesis of real-time scheduling algorithms for firm-deadline tasks.\r\nOn the analysis side, we leverage automata on infinite words to compute the competitive ratio of real-time schedulers subject to various environmental constraints.\r\nOn the synthesis side, we introduce a new instance of two-player mean-payoff partial-information games, and show\r\nhow the synthesis of an optimal real-time scheduler can be reduced to computing winning strategies in this new type of games." acknowledgement: "First, I am thankful to my advisor, Krishnendu Chatterjee, for offering me the opportunity to\r\nmaterialize my scientific curiosity in a remarkably wide range of interesting topics, as well as for his constant availability and continuous support throughout my doctoral studies. I have had the privilege of collaborating with, discussing and getting inspired by all members of my committee: Thomas A. Henzinger, Ulrich Schmid and Martin A. Nowak. The role of the above four people has been very instrumental both to the research carried out for this dissertation, and to the researcher I evolved to in the process.\r\nI have greatly enjoyed my numerous brainstorming sessions with Rasmus Ibsen-Jensen, many\r\nof which led to results on low-treewidth graphs presented here. I thank Alex Kößler for our\r\ndiscussions on modeling and analyzing real-time scheduling algorithms, Yaron Velner for our\r\ncollaboration on the Quantitative Interprocedural Analysis framework, and Nishant Sinha for our initial discussions on partial order reduction techniques in stateless model checking. I also thank Jan Otop, Ben Adlam, Bernhard Kragl and Josef Tkadlec for our fruitful collaborations on\r\ntopics outside the scope of this dissertation, as well as the interns Prateesh Goyal, Amir Kafshdar Goharshady, Samarth Mishra, Bhavya Choudhary and Marek Chalupa, with whom I have shared my excitement on various research topics. Together with my collaborators, I thank officemates and members of the Chatterjee and Henzinger groups throughout the years, Thorsten Tarrach, Ventsi Chonev, Roopsha Samanta, Przemek Daca, Mirco Giacobbe, Tanja Petrov, Ashutosh\r\nGupta, Arjun Radhakrishna, \ Petr Novontý, Christian Hilbe, Jakob Ruess, Martin Chmelik,\r\nCezara Dragoi, Johannes Reiter, Andrey Kupriyanov, Guy Avni, Sasha Rubin, Jessica Davies, Hongfei Fu, Thomas Ferrère, Pavol Cerný, Ali Sezgin, Jan Kretínský, Sergiy Bogomolov, Hui\r\nKong, Benjamin Aminof, Duc-Hiep Chu, and Damien Zufferey. Besides collaborations and office spaces, with many of the above people I have been fortunate to share numerous whiteboard\r\ndiscussions, as well as memorable long walks and amicable meals accompanied by stimulating\r\nconversations. I am highly indebted to Elisabeth Hacker for her continuous assistance in matters\r\nthat often exceeded her official duties, and who made my integration in Austria a smooth process." alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Andreas full_name: Pavlogiannis, Andreas id: 49704004-F248-11E8-B48F-1D18A9856A87 last_name: Pavlogiannis orcid: 0000-0002-8943-0722 citation: ama: Pavlogiannis A. Algorithmic advances in program analysis and their applications. 2017. doi:10.15479/AT:ISTA:th_854 apa: Pavlogiannis, A. (2017). Algorithmic advances in program analysis and their applications. Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:th_854 chicago: Pavlogiannis, Andreas. “Algorithmic Advances in Program Analysis and Their Applications.” Institute of Science and Technology Austria, 2017. https://doi.org/10.15479/AT:ISTA:th_854. ieee: A. Pavlogiannis, “Algorithmic advances in program analysis and their applications,” Institute of Science and Technology Austria, 2017. ista: Pavlogiannis A. 2017. Algorithmic advances in program analysis and their applications. Institute of Science and Technology Austria. mla: Pavlogiannis, Andreas. Algorithmic Advances in Program Analysis and Their Applications. Institute of Science and Technology Austria, 2017, doi:10.15479/AT:ISTA:th_854. short: A. Pavlogiannis, Algorithmic Advances in Program Analysis and Their Applications, Institute of Science and Technology Austria, 2017. date_created: 2018-12-11T11:48:41Z date_published: 2017-08-09T00:00:00Z date_updated: 2023-09-07T12:01:59Z day: '09' ddc: - '000' degree_awarded: PhD department: - _id: KrCh doi: 10.15479/AT:ISTA:th_854 ec_funded: 1 file: - access_level: open_access checksum: 3a3ec003f6ee73f41f82a544d63dfc77 content_type: application/pdf creator: system date_created: 2018-12-12T10:11:44Z date_updated: 2020-07-14T12:48:10Z file_id: '4900' file_name: IST-2017-854-v1+1_Pavlogiannis_Thesis_PubRep.pdf file_size: 4103115 relation: main_file - access_level: closed checksum: bd2facc45ff8a2e20c5ed313c2ccaa83 content_type: application/zip creator: dernst date_created: 2019-04-05T07:59:31Z date_updated: 2020-07-14T12:48:10Z file_id: '6201' file_name: 2017_thesis_Pavlogiannis.zip file_size: 14744374 relation: source_file file_date_updated: 2020-07-14T12:48:10Z has_accepted_license: '1' language: - iso: eng license: https://creativecommons.org/licenses/by-nd/4.0/ month: '08' oa: 1 oa_version: Published Version page: '418' project: - _id: 2584A770-B435-11E9-9278-68D0E5697425 call_identifier: FWF grant_number: P 23499-N23 name: Modern Graph Algorithmic Techniques in Formal Verification - _id: 25832EC2-B435-11E9-9278-68D0E5697425 call_identifier: FWF grant_number: S 11407_N23 name: Rigorous Systems Engineering - _id: 2581B60A-B435-11E9-9278-68D0E5697425 call_identifier: FP7 grant_number: '279307' name: 'Quantitative Graph Games: Theory and Applications' publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '6828' pubrep_id: '854' related_material: record: - id: '1071' relation: part_of_dissertation status: public - id: '1437' relation: part_of_dissertation status: public - id: '1602' relation: part_of_dissertation status: public - id: '1604' relation: part_of_dissertation status: public - id: '1607' relation: part_of_dissertation status: public - id: '1714' relation: part_of_dissertation status: public status: public supervisor: - first_name: Krishnendu full_name: Chatterjee, Krishnendu id: 2E5DCA20-F248-11E8-B48F-1D18A9856A87 last_name: Chatterjee orcid: 0000-0002-4561-241X title: Algorithmic advances in program analysis and their applications tmp: image: /image/cc_by_nd.png legal_code_url: https://creativecommons.org/licenses/by-nd/4.0/legalcode name: Creative Commons Attribution-NoDerivatives 4.0 International (CC BY-ND 4.0) short: CC BY-ND (4.0) type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2017' ... --- _id: '820' abstract: - lang: eng text: "The lac operon is a classic model system for bacterial gene regulation, and has been studied extensively in E. coli, a classic model organism. However, not much is known about E. coli’s ecology and life outside the laboratory, in particular in soil and water environments. The natural diversity of the lac operon outside the laboratory, its role in the ecology of E. coli and the selection pressures it is exposed to, are similarly unknown.\r\nIn Chapter Two of this thesis, I explore the genetic diversity, phylogenetic history and signatures of selection of the lac operon across 20 natural isolates of E. coli and divergent clades of Escherichia. I found that complete lac operons were present in all isolates examined, which in all but one case were functional. The lac operon phylogeny conformed to the whole-genome phylogeny of the divergent Escherichia clades, which excludes horizontal gene transfer as an explanation for the presence of functional lac operons in these clades. All lac operon genes showed a signature of purifying selection; this signature was strongest for the lacY gene. Lac operon genes of human and environmental isolates showed similar signatures of selection, except the lacZ gene, which showed a stronger signature of selection in environmental isolates.\r\nIn Chapter Three, I try to identify the natural genetic variation relevant for phenotype and fitness in the lac operon, comparing growth rate on lactose and LacZ activity of the lac operons of these wild isolates in a common genetic background. Sequence variation in the lac promoter region, upstream of the -10 and -35 RNA polymerase binding motif, predicted variation in LacZ activity at full induction, using a thermodynamic model of polymerase binding (Tugrul, 2016). However, neither variation in LacZ activity, nor RNA polymerase binding predicted by the model correlated with variation in growth rate. Lac operons of human and environmental isolates did not differ systematically in either growth rate on lactose or LacZ protein activity, suggesting that these lac operons have been exposed to similar selection pressures. We thus have no evidence that the phenotypic variation we measured is relevant for fitness.\r\nTo start assessing the effect of genomic background on the growth phenotype conferred by the lac operon, I compared growth on minimal medium with lactose between lac operon constructs and the corresponding original isolates, I found that maximal growth rate was determined by genomic background, with almost all backgrounds conferring higher growth rates than lab strain K12 MG1655. However, I found no evidence that the lactose concentration at which growth was half maximal depended on genomic background." acknowledgement: "ERC H2020 programme (grant agreement no. 648440)\r\nThanks to Jon Bollback for giving me the chance to do this work, for sharing the ideas that lay at the basis of this work, for his honesty and openness, showing himself to me as a person and not just as a boss. Thanks to Nick Barton for his guidance at the last stage, reading and commenting extensively on several versions of this manuscript, and for his encouragement; thanks to both Jon and Nick for their kindness and patience. Thanks to Erik van Nimwegen and Calin Guet for their time and willingness to be in my thesis committee, and to Erik van Nimwegen especially for agreeing to enter my thesis committee at the last moment, and for his very sharp, helpful and relevant comments during and after the defense. Thanks to my collaborators and discussion partners: Anne Kupczok, for her guidance, ideas and discussions during the construction of the manuscript of Chapter Two, and her comments on the manuscript; Georg Rieckh for making me aware of the issue of parameter identifiability, suggesting how to solve it, and for his unfortunate idea to start the plasmid enterprise in the first place; Murat Tugrul for sharing his model, for his enthusiasm, and his comments on Chapter Three; Srdjan Sarikas for his collaboration on the Monod model fitting, fast forwarding the analysis to turbo speed and making beautiful figures, and making the discussion fun on top of it all; Vanessa Barone for her last minute comments, especially on Chapter Three, providing a sharp and very helpful experimentalist perspective at the last moment; Maros Pleska and Marjon de Vos for their comments on the manuscript of Chapter Two; Gasper Tkacik for his crucial input on the relation between growth rate and lactose concentration; Bor Kavcic for his input on growth rate modeling and error propagation. Thanks to the Bollback, Bollenbach, Barton, Guet and Tkacik group members for both pro- viding an inspiring and supportive scientific environment to work in, as well as a lot of warmth and colour to everyday life. And thanks to the friends I found here, to the people who were there for me and to the people who changed my life, making it stranger and more beautiful than I could have imagined, Maros, Vanessa, Tade, Suzi, Andrej, Peter, Tiago, Kristof, Karin, Irene, Misha, Mato, Guillaume and Zanin. " alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Fabienne full_name: Jesse, Fabienne id: 4C8C26A4-F248-11E8-B48F-1D18A9856A87 last_name: Jesse citation: ama: Jesse F. The lac operon in the wild. 2017. doi:10.15479/AT:ISTA:th_857 apa: Jesse, F. (2017). The lac operon in the wild. Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:th_857 chicago: Jesse, Fabienne. “The Lac Operon in the Wild.” Institute of Science and Technology Austria, 2017. https://doi.org/10.15479/AT:ISTA:th_857. ieee: F. Jesse, “The lac operon in the wild,” Institute of Science and Technology Austria, 2017. ista: Jesse F. 2017. The lac operon in the wild. Institute of Science and Technology Austria. mla: Jesse, Fabienne. The Lac Operon in the Wild. Institute of Science and Technology Austria, 2017, doi:10.15479/AT:ISTA:th_857. short: F. Jesse, The Lac Operon in the Wild, Institute of Science and Technology Austria, 2017. date_created: 2018-12-11T11:48:41Z date_published: 2017-08-25T00:00:00Z date_updated: 2023-09-07T12:01:21Z day: '25' ddc: - '576' - '577' - '579' degree_awarded: PhD department: - _id: JoBo doi: 10.15479/AT:ISTA:th_857 ec_funded: 1 file: - access_level: open_access checksum: c62257a7bff0c5f39e1abffc6bfcca5c content_type: application/pdf creator: system date_created: 2018-12-12T10:17:00Z date_updated: 2020-07-14T12:48:10Z file_id: '5252' file_name: IST-2017-857-v1+1_thesis_fabienne.pdf file_size: 3417773 relation: main_file - access_level: closed checksum: fc87d7d72fce52824a3ae7dcad0413a8 content_type: application/x-tex creator: dernst date_created: 2019-04-05T08:51:59Z date_updated: 2020-07-14T12:48:10Z file_id: '6212' file_name: 2017_thesis_Jesse_source.tex file_size: 215899 relation: source_file file_date_updated: 2020-07-14T12:48:10Z has_accepted_license: '1' language: - iso: eng month: '08' oa: 1 oa_version: Published Version page: '87' project: - _id: 2578D616-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '648440' name: Selective Barriers to Horizontal Gene Transfer publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '6829' pubrep_id: '857' status: public supervisor: - first_name: Jonathan P full_name: Bollback, Jonathan P id: 2C6FA9CC-F248-11E8-B48F-1D18A9856A87 last_name: Bollback orcid: 0000-0002-4624-4612 title: The lac operon in the wild tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2017' ... --- _id: '838' abstract: - lang: eng text: 'In this thesis we discuss the exact security of message authentications codes HMAC , NMAC , and PMAC . NMAC is a mode of operation which turns a fixed input-length keyed hash function f into a variable input-length function. A practical single-key variant of NMAC called HMAC is a very popular and widely deployed message authentication code (MAC). PMAC is a block-cipher based mode of operation, which also happens to be the most famous fully parallel MAC. NMAC was introduced by Bellare, Canetti and Krawczyk Crypto’96, who proved it to be a secure pseudorandom function (PRF), and thus also a MAC, under two assumptions. Unfortunately, for many instantiations of HMAC one of them has been found to be wrong. To restore the provable guarantees for NMAC , Bellare [Crypto’06] showed its security without this assumption. PMAC was introduced by Black and Rogaway at Eurocrypt 2002. If instantiated with a pseudorandom permutation over n -bit strings, PMAC constitutes a provably secure variable input-length PRF. For adversaries making q queries, each of length at most ` (in n -bit blocks), and of total length σ ≤ q` , the original paper proves an upper bound on the distinguishing advantage of O ( σ 2 / 2 n ), while the currently best bound is O ( qσ/ 2 n ). In this work we show that this bound is tight by giving an attack with advantage Ω( q 2 `/ 2 n ). In the PMAC construction one initially XORs a mask to every message block, where the mask for the i th block is computed as τ i := γ i · L , where L is a (secret) random value, and γ i is the i -th codeword of the Gray code. Our attack applies more generally to any sequence of γ i ’s which contains a large coset of a subgroup of GF (2 n ). As for NMAC , our first contribution is a simpler and uniform proof: If f is an ε -secure PRF (against q queries) and a δ - non-adaptively secure PRF (against q queries), then NMAC f is an ( ε + `qδ )-secure PRF against q queries of length at most ` blocks each. We also show that this ε + `qδ bound is basically tight by constructing an f for which an attack with advantage `qδ exists. Moreover, we analyze the PRF-security of a modification of NMAC called NI by An and Bellare that avoids the constant rekeying on multi-block messages in NMAC and allows for an information-theoretic analysis. We carry out such an analysis, obtaining a tight `q 2 / 2 c bound for this step, improving over the trivial bound of ` 2 q 2 / 2 c . Finally, we investigate, if the security of PMAC can be further improved by using τ i ’s that are k -wise independent, for k > 1 (the original has k = 1). We observe that the security of PMAC will not increase in general if k = 2, and then prove that the security increases to O ( q 2 / 2 n ), if the k = 4. Due to simple extension attacks, this is the best bound one can hope for, using any distribution on the masks. Whether k = 3 is already sufficient to get this level of security is left as an open problem. Keywords: Message authentication codes, Pseudorandom functions, HMAC, PMAC. ' alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Michal full_name: Rybar, Michal id: 2B3E3DE8-F248-11E8-B48F-1D18A9856A87 last_name: Rybar citation: ama: Rybar M. (The exact security of) Message authentication codes. 2017. doi:10.15479/AT:ISTA:th_828 apa: Rybar, M. (2017). (The exact security of) Message authentication codes. Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:th_828 chicago: Rybar, Michal. “(The Exact Security of) Message Authentication Codes.” Institute of Science and Technology Austria, 2017. https://doi.org/10.15479/AT:ISTA:th_828. ieee: M. Rybar, “(The exact security of) Message authentication codes,” Institute of Science and Technology Austria, 2017. ista: Rybar M. 2017. (The exact security of) Message authentication codes. Institute of Science and Technology Austria. mla: Rybar, Michal. (The Exact Security of) Message Authentication Codes. Institute of Science and Technology Austria, 2017, doi:10.15479/AT:ISTA:th_828. short: M. Rybar, (The Exact Security of) Message Authentication Codes, Institute of Science and Technology Austria, 2017. date_created: 2018-12-11T11:48:46Z date_published: 2017-06-26T00:00:00Z date_updated: 2023-09-07T12:02:28Z day: '26' ddc: - '000' degree_awarded: PhD department: - _id: KrPi doi: 10.15479/AT:ISTA:th_828 file: - access_level: open_access checksum: ff8639ec4bded6186f44c7bd3ee26804 content_type: application/pdf creator: system date_created: 2018-12-12T10:10:13Z date_updated: 2020-07-14T12:48:12Z file_id: '4799' file_name: IST-2017-828-v1+3_2017_Rybar_thesis.pdf file_size: 847400 relation: main_file - access_level: closed checksum: 3462101745ce8ad199c2d0f75dae4a7e content_type: application/zip creator: dernst date_created: 2019-04-05T08:24:11Z date_updated: 2020-07-14T12:48:12Z file_id: '6202' file_name: 2017_Thesis_Rybar_source.zip file_size: 26054879 relation: source_file file_date_updated: 2020-07-14T12:48:12Z has_accepted_license: '1' language: - iso: eng month: '06' oa: 1 oa_version: Published Version page: '86' publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '6810' pubrep_id: '828' related_material: record: - id: '2082' relation: part_of_dissertation status: public - id: '6196' relation: part_of_dissertation status: public status: public title: (The exact security of) Message authentication codes type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2017' ... --- _id: '837' abstract: - lang: eng text: 'The hippocampus is a key brain region for memory and notably for spatial memory, and is needed for both spatial working and reference memories. Hippocampal place cells selectively discharge in specific locations of the environment to form mnemonic represen tations of space. Several behavioral protocols have been designed to test spatial memory which requires the experimental subject to utilize working memory and reference memory. However, less is known about how these memory traces are presented in the hippo campus, especially considering tasks that require both spatial working and long -term reference memory demand. The aim of my thesis was to elucidate how spatial working memory, reference memory, and the combination of both are represented in the hippocampus. In this thesis, using a radial eight -arm maze, I examined how the combined demand on these memories influenced place cell assemblies while reference memories were partially updated by changing some of the reward- arms. This was contrasted with task varian ts requiring working or reference memories only. Reference memory update led to gradual place field shifts towards the rewards on the switched arms. Cells developed enhanced firing in passes between newly -rewarded arms as compared to those containing an unchanged reward. The working memory task did not show such gradual changes. Place assemblies on occasions replayed trajectories of the maze; at decision points the next arm choice was preferentially replayed in tasks needing reference memory while in the pure working memory task the previously visited arm was replayed. Hence trajectory replay only reflected the decision of the animal in tasks needing reference memory update. At the reward locations, in all three tasks outbound trajectories of the current arm were preferentially replayed, showing the animals’ next path to the center. At reward locations trajectories were replayed preferentially in reverse temporal order. Moreover, in the center reverse replay was seen in the working memory task but in the other tasks forward replay was seen. Hence, the direction of reactivation was determined by the goal locations so that part of the trajectory which was closer to the goal was reactivated later in an HSE while places further away from the goal were reactivated earlier. Altogether my work demonstrated that reference memory update triggers several levels of reorganization of the hippocampal cognitive map which are not seen in simpler working memory demand s. Moreover, hippocampus is likely to be involved in spatial decisions through reactivating planned trajectories when reference memory recall is required for such a decision. ' acknowledgement: 'I am very grateful for the opportunity I have had as a graduate student to explore and incredibly interesting branch of neuroscience, and for the people who made it possible. Firstly, I would like to offer my thanks to my supervisor Professor Jozsef Csicsvari for his great support, guidance and patience offered over the years. The door to his office was always open whenever I had questions. I have learned a lot from him about carefully designing experiments, asking interesting questions and how to integrate results into a broader picture. I also express my gratitude to the remarkable post- doc , Dr. Joseph O’Neill. He is a gre at scientific role model who is always willing to teach , and advice and talk through problems with his full attention. Many thanks to my wonderful “office mates” over the years and their support and encouragement, Alice Avernhe, Philipp Schönenberger, Desiree Dickerson, Karel Blahna, Charlotte Boccara, Igor Gridchyn, Peter Baracskay, Krisztián Kovács, Dámaris Rangel, Karola Käfer and Federico Stella. They were the ones in the lab for the many useful discussions about science and for making the laboratory such a nice and friendly place to work in. A special thank goes to Michael LoBianco and Jago Wallenschus for wonderful technical support. I would also like to thank Professor Peter Jonas and Professor David M Bannerman for being my qualifying exam and thesi s committee members despite their busy schedule. I am also very thankful to IST Austria for their support all throughout my PhD. ' alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Haibing full_name: Xu, Haibing id: 310349D0-F248-11E8-B48F-1D18A9856A87 last_name: Xu citation: ama: Xu H. Reactivation of the hippocampal cognitive map in goal-directed spatial tasks. 2017. doi:10.15479/AT:ISTA:th_858 apa: Xu, H. (2017). Reactivation of the hippocampal cognitive map in goal-directed spatial tasks. Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:th_858 chicago: Xu, Haibing. “Reactivation of the Hippocampal Cognitive Map in Goal-Directed Spatial Tasks.” Institute of Science and Technology Austria, 2017. https://doi.org/10.15479/AT:ISTA:th_858. ieee: H. Xu, “Reactivation of the hippocampal cognitive map in goal-directed spatial tasks,” Institute of Science and Technology Austria, 2017. ista: Xu H. 2017. Reactivation of the hippocampal cognitive map in goal-directed spatial tasks. Institute of Science and Technology Austria. mla: Xu, Haibing. Reactivation of the Hippocampal Cognitive Map in Goal-Directed Spatial Tasks. Institute of Science and Technology Austria, 2017, doi:10.15479/AT:ISTA:th_858. short: H. Xu, Reactivation of the Hippocampal Cognitive Map in Goal-Directed Spatial Tasks, Institute of Science and Technology Austria, 2017. date_created: 2018-12-11T11:48:46Z date_published: 2017-08-23T00:00:00Z date_updated: 2023-09-07T12:06:38Z day: '23' ddc: - '571' degree_awarded: PhD department: - _id: JoCs doi: 10.15479/AT:ISTA:th_858 file: - access_level: closed checksum: f11925fbbce31e495124b6bc4f10573c content_type: application/vnd.openxmlformats-officedocument.wordprocessingml.document creator: dernst date_created: 2019-04-05T08:59:51Z date_updated: 2020-07-14T12:48:12Z file_id: '6213' file_name: 2017_Xu_Haibing_Thesis_Source.docx file_size: 3589490 relation: source_file - access_level: open_access checksum: ffb10749a537d615fab1ef0937ccb157 content_type: application/pdf creator: dernst date_created: 2019-04-05T08:59:51Z date_updated: 2020-07-14T12:48:12Z file_id: '6214' file_name: 2017_Xu_Thesis_IST.pdf file_size: 11668613 relation: main_file file_date_updated: 2020-07-14T12:48:12Z has_accepted_license: '1' language: - iso: eng month: '08' oa: 1 oa_version: Published Version page: '93' publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '6811' pubrep_id: '858' related_material: record: - id: '5828' relation: part_of_dissertation status: public status: public supervisor: - first_name: Jozsef L full_name: Csicsvari, Jozsef L id: 3FA14672-F248-11E8-B48F-1D18A9856A87 last_name: Csicsvari orcid: 0000-0002-5193-4036 title: Reactivation of the hippocampal cognitive map in goal-directed spatial tasks tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2017' ... --- _id: '938' abstract: - lang: eng text: The thesis encompasses several topics of plant cell biology which were studied in the model plant Arabidopsis thaliana. Chapter 1 concerns the plant hormone auxin and its polar transport through cells and tissues. The highly controlled, directional transport of auxin is facilitated by plasma membrane-localized transporters. Transporters from the PIN family direct auxin transport due to their polarized localizations at cell membranes. Substantial effort has been put into research on cellular trafficking of PIN proteins, which is thought to underlie their polar distribution. I participated in a forward genetic screen aimed at identifying novel regulators of PIN polarity. The screen yielded several genes which may be involved in PIN polarity regulation or participate in polar auxin transport by other means. Chapter 2 focuses on the endomembrane system, with particular attention to clathrin-mediated endocytosis. The project started with identification of several proteins that interact with clathrin light chains. Among them, I focused on two putative homologues of auxilin, which in non-plant systems is an endocytotic factor known for uncoating clathrin-coated vesicles in the final step of endocytosis. The body of my work consisted of an in-depth characterization of transgenic A. thaliana lines overexpressing these putative auxilins in an inducible manner. Overexpression of these proteins leads to an inhibition of endocytosis, as documented by imaging of cargoes and clathrin-related endocytic machinery. An extension of this work is an investigation into a concept of homeostatic regulation acting between distinct transport processes in the endomembrane system. With auxilin overexpressing lines, where endocytosis is blocked specifically, I made observations on the mutual relationship between two opposite trafficking processes of secretion and endocytosis. In Chapter 3, I analyze cortical microtubule arrays and their relationship to auxin signaling and polarized growth in elongating cells. In plants, microtubules are organized into arrays just below the plasma membrane, and it is thought that their function is to guide membrane-docked cellulose synthase complexes. These, in turn, influence cell wall structure and cell shape by directed deposition of cellulose fibres. In elongating cells, cortical microtubule arrays are able to reorient in relation to long cell axis, and these reorientations have been linked to cell growth and to signaling of growth-regulating factors such as auxin or light. In this chapter, I am addressing the causal relationship between microtubule array reorientation, growth, and auxin signaling. I arrive at a model where array reorientation is not guided by auxin directly, but instead is only controlled by growth, which, in turn, is regulated by auxin. alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Maciek full_name: Adamowski, Maciek id: 45F536D2-F248-11E8-B48F-1D18A9856A87 last_name: Adamowski orcid: 0000-0001-6463-5257 citation: ama: Adamowski M. Investigations into cell polarity and trafficking in the plant model Arabidopsis thaliana . 2017. doi:10.15479/AT:ISTA:th_842 apa: Adamowski, M. (2017). Investigations into cell polarity and trafficking in the plant model Arabidopsis thaliana . Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:th_842 chicago: Adamowski, Maciek. “Investigations into Cell Polarity and Trafficking in the Plant Model Arabidopsis Thaliana .” Institute of Science and Technology Austria, 2017. https://doi.org/10.15479/AT:ISTA:th_842. ieee: M. Adamowski, “Investigations into cell polarity and trafficking in the plant model Arabidopsis thaliana ,” Institute of Science and Technology Austria, 2017. ista: Adamowski M. 2017. Investigations into cell polarity and trafficking in the plant model Arabidopsis thaliana . Institute of Science and Technology Austria. mla: Adamowski, Maciek. Investigations into Cell Polarity and Trafficking in the Plant Model Arabidopsis Thaliana . Institute of Science and Technology Austria, 2017, doi:10.15479/AT:ISTA:th_842. short: M. Adamowski, Investigations into Cell Polarity and Trafficking in the Plant Model Arabidopsis Thaliana , Institute of Science and Technology Austria, 2017. date_created: 2018-12-11T11:49:18Z date_published: 2017-06-02T00:00:00Z date_updated: 2023-09-07T12:06:09Z day: '02' ddc: - '581' - '583' - '580' degree_awarded: PhD department: - _id: JiFr doi: 10.15479/AT:ISTA:th_842 file: - access_level: closed checksum: 193425764d9aaaed3ac57062a867b315 content_type: application/vnd.openxmlformats-officedocument.wordprocessingml.document creator: dernst date_created: 2019-04-05T09:03:20Z date_updated: 2020-07-14T12:48:15Z file_id: '6215' file_name: 2017_Adamowski-Thesis_Source.docx file_size: 46903863 relation: source_file - access_level: open_access checksum: df5ab01be81f821e1b958596a1ec8d21 content_type: application/pdf creator: dernst date_created: 2019-04-05T09:03:19Z date_updated: 2020-07-14T12:48:15Z file_id: '6216' file_name: 2017_Adamowski-Thesis.pdf file_size: 8698888 relation: main_file file_date_updated: 2020-07-14T12:48:15Z has_accepted_license: '1' language: - iso: eng month: '06' oa: 1 oa_version: Published Version page: '117' publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '6483' pubrep_id: '842' related_material: record: - id: '1591' relation: part_of_dissertation status: public status: public supervisor: - first_name: Jiří full_name: Friml, Jiří id: 4159519E-F248-11E8-B48F-1D18A9856A87 last_name: Friml orcid: 0000-0002-8302-7596 title: 'Investigations into cell polarity and trafficking in the plant model Arabidopsis thaliana ' type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2017' ... --- _id: '992' abstract: - lang: eng text: "An instance of the Constraint Satisfaction Problem (CSP) is given by a finite set of\r\nvariables, a finite domain of labels, and a set of constraints, each constraint acting on\r\na subset of the variables. The goal is to find an assignment of labels to its variables\r\nthat satisfies all constraints (or decide whether one exists). If we allow more general\r\n“soft” constraints, which come with (possibly infinite) costs of particular assignments,\r\nwe obtain instances from a richer class called Valued Constraint Satisfaction Problem\r\n(VCSP). There the goal is to find an assignment with minimum total cost.\r\nIn this thesis, we focus (assuming that P\r\n6\r\n=\r\nNP) on classifying computational com-\r\nplexity of CSPs and VCSPs under certain restricting conditions. Two results are the core\r\ncontent of the work. In one of them, we consider VCSPs parametrized by a constraint\r\nlanguage, that is the set of “soft” constraints allowed to form the instances, and finish\r\nthe complexity classification modulo (missing pieces of) complexity classification for\r\nanalogously parametrized CSP. The other result is a generalization of Edmonds’ perfect\r\nmatching algorithm. This generalization contributes to complexity classfications in two\r\nways. First, it gives a new (largest known) polynomial-time solvable class of Boolean\r\nCSPs in which every variable may appear in at most two constraints and second, it\r\nsettles full classification of Boolean CSPs with planar drawing (again parametrized by a\r\nconstraint language)." acknowledgement: FP7/2007-2013/ERC grant agreement no 616160 alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Michal full_name: Rolinek, Michal id: 3CB3BC06-F248-11E8-B48F-1D18A9856A87 last_name: Rolinek citation: ama: Rolinek M. Complexity of constraint satisfaction. 2017. doi:10.15479/AT:ISTA:th_815 apa: Rolinek, M. (2017). Complexity of constraint satisfaction. Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:th_815 chicago: Rolinek, Michal. “Complexity of Constraint Satisfaction.” Institute of Science and Technology Austria, 2017. https://doi.org/10.15479/AT:ISTA:th_815. ieee: M. Rolinek, “Complexity of constraint satisfaction,” Institute of Science and Technology Austria, 2017. ista: Rolinek M. 2017. Complexity of constraint satisfaction. Institute of Science and Technology Austria. mla: Rolinek, Michal. Complexity of Constraint Satisfaction. Institute of Science and Technology Austria, 2017, doi:10.15479/AT:ISTA:th_815. short: M. Rolinek, Complexity of Constraint Satisfaction, Institute of Science and Technology Austria, 2017. date_created: 2018-12-11T11:49:35Z date_published: 2017-05-01T00:00:00Z date_updated: 2023-09-07T12:05:41Z day: '01' ddc: - '004' degree_awarded: PhD department: - _id: VlKo doi: 10.15479/AT:ISTA:th_815 ec_funded: 1 file: - access_level: open_access checksum: 81761fb939acb7585c36629f765b4373 content_type: application/pdf creator: system date_created: 2018-12-12T10:07:55Z date_updated: 2020-07-14T12:48:18Z file_id: '4654' file_name: IST-2017-815-v1+3_final_blank_signature_maybe_pdfa.pdf file_size: 786145 relation: main_file - access_level: closed checksum: 2b2d7e1d6c1c79a9795a7aa0f860baf3 content_type: application/zip creator: dernst date_created: 2019-04-05T08:43:24Z date_updated: 2020-07-14T12:48:18Z file_id: '6208' file_name: 2017_Thesis_Rolinek_source.zip file_size: 5936337 relation: source_file file_date_updated: 2020-07-14T12:48:18Z has_accepted_license: '1' language: - iso: eng month: '05' oa: 1 oa_version: Published Version page: '97' project: - _id: 25FBA906-B435-11E9-9278-68D0E5697425 call_identifier: FP7 grant_number: '616160' name: 'Discrete Optimization in Computer Vision: Theory and Practice' publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '6407' pubrep_id: '815' status: public supervisor: - first_name: Vladimir full_name: Kolmogorov, Vladimir id: 3D50B0BA-F248-11E8-B48F-1D18A9856A87 last_name: Kolmogorov title: Complexity of constraint satisfaction type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2017' ... --- _id: '202' abstract: - lang: eng text: 'Restriction-modification (RM) represents the simplest and possibly the most widespread mechanism of self/non-self discrimination in nature. In order to provide bacteria with immunity against bacteriophages and other parasitic genetic elements, RM systems rely on a balance between two enzymes: the restriction enzyme, which cleaves non-self DNA at specific restriction sites, and the modification enzyme, which tags the host’s DNA as self and thus protects it from cleavage. In this thesis, I use population and single-cell level experiments in combination with mathematical modeling to study different aspects of the interplay between RM systems, bacteria and bacteriophages. First, I analyze how mutations in phage restriction sites affect the probability of phage escape – an inherently stochastic process, during which phages accidently get modified instead of restricted. Next, I use single-cell experiments to show that RM systems can, with a low probability, attack the genome of their bacterial host and that this primitive form of autoimmunity leads to a tradeoff between the evolutionary cost and benefit of RM systems. Finally, I investigate the nature of interactions between bacteria, RM systems and temperate bacteriophages to find that, as a consequence of phage escape and its impact on population dynamics, RM systems can promote acquisition of symbiotic bacteriophages, rather than limit it. The results presented here uncover new fundamental biological properties of RM systems and highlight their importance in the ecology and evolution of bacteria, bacteriophages and their interactions.' acknowledgement: "During my PhD studies, I received help from many people, all of which unfortunately cannot be listed here. I thank them deeply and hope that I never made them regret their kindness.\r\nI would like to express my deepest gratitude to Călin Guet, who went far beyond his responsibilities as an advisor and was to me also a great mentor and a friend. Călin never questioned my potential or lacked compassion and I cannot thank him enough for cultivating in me an independent scientist. I was amazed by his ability to recognize the most fascinating scientific problems in objects of study that others would find mundane. I hope I adopted at least a fraction of this ability.\r\nI will be forever grateful to Bruce Levin for all his support and especially for giving me the best possible example of how one can practice excellent science with humor and style. Working with Bruce was a true privilege.\r\nI thank Jonathan Bollback and Gašper Tkačik for serving in my PhD committee and the Austrian Academy of Science for funding my PhD research via the DOC fellowship.\r\nI thank all our lab members: Tobias Bergmiller for his guidance, especially in the first years of my research, and for being a good friend throughout; Remy Chait for staying in the lab at unreasonable hours and for the good laughs at bad jokes we shared; Anna Staron for supportively listening to my whines whenever I had to run a gel; Magdalena Steinrück for her pioneering work in the lab; Kathrin Tomasek for keeping the entropic forces in check and for her FACS virtuosity; Isabella Tomanek for always being nice to me, no matter how much bench space I took from her.\r\nI thank all my collaborators: Reiko Okura and Yuichi Wakamoto for performing and analyzing the microfluidic experiments; Long Qian and Edo Kussell for their bioinformatics analysis; Dominik Refardt for the λ kan phage; Moritz for his help with the mathematical modeling. I thank Fabienne Jesse for her tireless editorial work on all our manuscripts.\r\nFinally, I would like to thank my family and especially my wife Edita, who sacrificed a lot so that I can pursue my goals and dreams.\r\n" alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Maros full_name: Pleska, Maros id: 4569785E-F248-11E8-B48F-1D18A9856A87 last_name: Pleska orcid: 0000-0001-7460-7479 citation: ama: Pleska M. Biology of restriction-modification systems at the single-cell and population level. 2017. doi:10.15479/AT:ISTA:th_916 apa: Pleska, M. (2017). Biology of restriction-modification systems at the single-cell and population level. Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:th_916 chicago: Pleska, Maros. “Biology of Restriction-Modification Systems at the Single-Cell and Population Level.” Institute of Science and Technology Austria, 2017. https://doi.org/10.15479/AT:ISTA:th_916. ieee: M. Pleska, “Biology of restriction-modification systems at the single-cell and population level,” Institute of Science and Technology Austria, 2017. ista: Pleska M. 2017. Biology of restriction-modification systems at the single-cell and population level. Institute of Science and Technology Austria. mla: Pleska, Maros. Biology of Restriction-Modification Systems at the Single-Cell and Population Level. Institute of Science and Technology Austria, 2017, doi:10.15479/AT:ISTA:th_916. short: M. Pleska, Biology of Restriction-Modification Systems at the Single-Cell and Population Level, Institute of Science and Technology Austria, 2017. date_created: 2018-12-11T11:45:10Z date_published: 2017-10-01T00:00:00Z date_updated: 2023-09-15T12:04:56Z day: '01' ddc: - '576' - '579' degree_awarded: PhD department: - _id: CaGu doi: 10.15479/AT:ISTA:th_916 file: - access_level: open_access checksum: 33cfb59674e91f82e3738396d3fb3776 content_type: application/pdf creator: system date_created: 2018-12-12T10:08:48Z date_updated: 2020-07-14T12:45:24Z file_id: '4710' file_name: IST-2018-916-v1+3_2017_Pleska_Maros_Thesis.pdf file_size: 18569590 relation: main_file - access_level: closed checksum: dcc239968decb233e7f98cf1083d8c26 content_type: application/vnd.openxmlformats-officedocument.wordprocessingml.document creator: dernst date_created: 2019-04-05T08:33:14Z date_updated: 2020-07-14T12:45:24Z file_id: '6204' file_name: 2017_Pleska_Maros_Thesis.docx file_size: 2801649 relation: source_file file_date_updated: 2020-07-14T12:45:24Z has_accepted_license: '1' language: - iso: eng month: '10' oa: 1 oa_version: Published Version page: '126' project: - _id: 251D65D8-B435-11E9-9278-68D0E5697425 grant_number: '24210' name: Effects of Stochasticity on the Function of Restriction-Modi cation Systems at the Single-Cell Level (DOC Fellowship) publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '7711' pubrep_id: '916' related_material: record: - id: '1243' relation: part_of_dissertation status: public - id: '561' relation: part_of_dissertation status: public - id: '457' relation: part_of_dissertation status: public status: public supervisor: - first_name: Calin C full_name: Guet, Calin C id: 47F8433E-F248-11E8-B48F-1D18A9856A87 last_name: Guet orcid: 0000-0001-6220-2052 title: Biology of restriction-modification systems at the single-cell and population level tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2017' ... --- _id: '6287' abstract: - lang: eng text: The main objects considered in the present work are simplicial and CW-complexes with vertices forming a random point cloud. In particular, we consider a Poisson point process in R^n and study Delaunay and Voronoi complexes of the first and higher orders and weighted Delaunay complexes obtained as sections of Delaunay complexes, as well as the Čech complex. Further, we examine theDelaunay complex of a Poisson point process on the sphere S^n, as well as of a uniform point cloud, which is equivalent to the convex hull, providing a connection to the theory of random polytopes. Each of the complexes in question can be endowed with a radius function, which maps its cells to the radii of appropriately chosen circumspheres, called the radius of the cell. Applying and developing discrete Morse theory for these functions, joining it together with probabilistic and sometimes analytic machinery, and developing several integral geometric tools, we aim at getting the distributions of circumradii of typical cells. For all considered complexes, we are able to generalize and obtain up to constants the distribution of radii of typical intervals of all types. In low dimensions the constants can be computed explicitly, thus providing the explicit expressions for the expected numbers of cells. In particular, it allows to find the expected density of simplices of every dimension for a Poisson point process in R^4, whereas the result for R^3 was known already in 1970's. alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Anton full_name: Nikitenko, Anton id: 3E4FF1BA-F248-11E8-B48F-1D18A9856A87 last_name: Nikitenko orcid: 0000-0002-0659-3201 citation: ama: Nikitenko A. Discrete Morse theory for random complexes . 2017. doi:10.15479/AT:ISTA:th_873 apa: Nikitenko, A. (2017). Discrete Morse theory for random complexes . Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:th_873 chicago: Nikitenko, Anton. “Discrete Morse Theory for Random Complexes .” Institute of Science and Technology Austria, 2017. https://doi.org/10.15479/AT:ISTA:th_873. ieee: A. Nikitenko, “Discrete Morse theory for random complexes ,” Institute of Science and Technology Austria, 2017. ista: Nikitenko A. 2017. Discrete Morse theory for random complexes . Institute of Science and Technology Austria. mla: Nikitenko, Anton. Discrete Morse Theory for Random Complexes . Institute of Science and Technology Austria, 2017, doi:10.15479/AT:ISTA:th_873. short: A. Nikitenko, Discrete Morse Theory for Random Complexes , Institute of Science and Technology Austria, 2017. date_created: 2019-04-09T15:04:32Z date_published: 2017-10-27T00:00:00Z date_updated: 2023-09-15T12:10:34Z day: '27' ddc: - '514' - '516' - '519' degree_awarded: PhD department: - _id: HeEd doi: 10.15479/AT:ISTA:th_873 file: - access_level: open_access checksum: ece7e598a2f060b263c2febf7f3fe7f9 content_type: application/pdf creator: dernst date_created: 2019-04-09T14:54:51Z date_updated: 2020-07-14T12:47:26Z file_id: '6289' file_name: 2017_Thesis_Nikitenko.pdf file_size: 2324870 relation: main_file - access_level: closed checksum: 99b7ad76e317efd447af60f91e29b49b content_type: application/zip creator: dernst date_created: 2019-04-09T14:54:51Z date_updated: 2020-07-14T12:47:26Z file_id: '6290' file_name: 2017_Thesis_Nikitenko_source.zip file_size: 2863219 relation: source_file file_date_updated: 2020-07-14T12:47:26Z has_accepted_license: '1' language: - iso: eng month: '10' oa: 1 oa_version: Published Version page: '86' publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria pubrep_id: '873' related_material: record: - id: '718' relation: part_of_dissertation status: public - id: '5678' relation: part_of_dissertation status: public - id: '87' relation: part_of_dissertation status: public status: public supervisor: - first_name: Herbert full_name: Edelsbrunner, Herbert id: 3FB178DA-F248-11E8-B48F-1D18A9856A87 last_name: Edelsbrunner orcid: 0000-0002-9823-6833 title: 'Discrete Morse theory for random complexes ' tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2017' ... --- _id: '1127' abstract: - lang: eng text: "Plant hormone auxin and its transport between cells belong to the most important\r\nmechanisms controlling plant development. Auxin itself could change localization of PINs and\r\nthereby control direction of its own flow. We performed an expression profiling experiment\r\nin Arabidopsis roots to identify potential regulators of PIN polarity which are transcriptionally\r\nregulated by auxin signalling. We identified several novel regulators and performed a detailed\r\ncharacterization of the transcription factor WRKY23 (At2g47260) and its role in auxin\r\nfeedback on PIN polarity. Gain-of-function and dominant-negative mutants revealed that\r\nWRKY23 plays a crucial role in mediating the auxin effect on PIN polarity. In concordance,\r\ntypical polar auxin transport processes such as gravitropism and leaf vascular pattern\r\nformation were disturbed by interfering with WRKY23 function.\r\nIn order to identify direct targets of WRKY23, we performed consequential expression\r\nprofiling experiments using a WRKY23 inducible gain-of-function line and dominant-negative\r\nWRKY23 line that is defunct in PIN re-arrangement. Among several genes mostly related to\r\nthe groups of cell wall and defense process regulators, we identified LYSINE-HISTIDINE\r\nTRANSPORTER 1 (LHT1; At5g40780), a small amino acid permease gene from the amino\r\nacid/auxin permease family (AAAP), we present its detailed characterisation in auxin feedback\r\non PIN repolarization, identified its transcriptional regulation, we propose a potential\r\nmechanism of its action. Moreover, we identified also a member of receptor-like protein\r\nkinase LRR-RLK (LEUCINE-RICH REPEAT TRANSMEMBRANE PROTEIN KINASE PROTEIN 1;\r\nLRRK1; At1g05700), which also affects auxin-dependent PIN re-arrangement. We described\r\nits transcriptional behaviour, subcellular localization. Based on global expression data, we\r\ntried to identify ligand responsible for mechanism of signalling and suggest signalling partner\r\nand interactors. Additionally, we described role of novel phytohormone group, strigolactone,\r\nin auxin-dependent PIN re-arrangement, that could be a fundament for future studies in this\r\nfield.\r\nOur results provide first insights into an auxin transcriptional network targeting PIN\r\nlocalization and thus regulating plant development. We highlighted WRKY23 transcriptional\r\nnetwork and characterised its mediatory role in plant development. We identified direct\r\neffectors of this network, LHT1 and LRRK1, and describe their roles in PIN re-arrangement and\r\nPIN-dependent auxin transport processes." acknowledgement: I would like to first acknowledge my supervisor Jiří Friml for support, kind advice and patience. It was a pleasure to be a part of your lab, Jiří. I will remember the atmosphere present in auxin lab at VIB in Ghent and at IST in Klosterneuburg forever. I would like to thank all past and present lab members for the friendship and friendly and scientific environment in the groups. It was so nice to cooperate with you, guys. There was always someone who helped me with experiments, troubleshoot issues coming from our work etc. At this place, I would like to thank especially to Gergo Molnár. I’m happy (and lucky) that I have met him; he naturally became my tutor and guide through my PhD. From no one else during my entire professional career, I’ve learned that much. alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Tomas full_name: Prat, Tomas id: 3DA3BFEE-F248-11E8-B48F-1D18A9856A87 last_name: Prat citation: ama: Prat T. Identification of novel regulators of PIN polarity and development of novel auxin sensor. 2017. apa: Prat, T. (2017). Identification of novel regulators of PIN polarity and development of novel auxin sensor. Institute of Science and Technology Austria. chicago: Prat, Tomas. “Identification of Novel Regulators of PIN Polarity and Development of Novel Auxin Sensor.” Institute of Science and Technology Austria, 2017. ieee: T. Prat, “Identification of novel regulators of PIN polarity and development of novel auxin sensor,” Institute of Science and Technology Austria, 2017. ista: Prat T. 2017. Identification of novel regulators of PIN polarity and development of novel auxin sensor. Institute of Science and Technology Austria. mla: Prat, Tomas. Identification of Novel Regulators of PIN Polarity and Development of Novel Auxin Sensor. Institute of Science and Technology Austria, 2017. short: T. Prat, Identification of Novel Regulators of PIN Polarity and Development of Novel Auxin Sensor, Institute of Science and Technology Austria, 2017. date_created: 2018-12-11T11:50:17Z date_published: 2017-01-12T00:00:00Z date_updated: 2023-09-19T10:39:33Z day: '12' ddc: - '580' degree_awarded: PhD department: - _id: JiFr file: - access_level: closed checksum: d192c7c6c5ea32c8432437286dc4909e content_type: application/pdf creator: dernst date_created: 2019-04-05T08:45:14Z date_updated: 2019-04-05T08:45:14Z file_id: '6209' file_name: IST_Austria_Thesis_Tomáš_Prát.pdf file_size: 10285946 relation: main_file - access_level: open_access checksum: bab18b52cf98145926042d8ed99fdb3b content_type: application/pdf creator: dernst date_created: 2021-02-22T11:52:56Z date_updated: 2021-02-22T11:52:56Z file_id: '9185' file_name: 2017_Thesis_Prat.pdf file_size: 9802991 relation: main_file success: 1 file_date_updated: 2021-02-22T11:52:56Z has_accepted_license: '1' language: - iso: eng month: '01' oa: 1 oa_version: Published Version page: '131' publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '6233' related_material: record: - id: '449' relation: part_of_dissertation status: public status: public supervisor: - first_name: Jiří full_name: Friml, Jiří id: 4159519E-F248-11E8-B48F-1D18A9856A87 last_name: Friml orcid: 0000-0002-8302-7596 title: Identification of novel regulators of PIN polarity and development of novel auxin sensor type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2017' ... --- _id: '961' abstract: - lang: eng text: Cell-cell contact formation constitutes the first step in the emergence of multicellularity in evolution, thereby allowing the differentiation of specialized cell types. In metazoan development, cell-cell contact formation is thought to influence cell fate specification, and cell fate specification has been implicated in cell-cell contact formation. However, remarkably little is yet known about whether and how the interaction and feedback between cell-cell contact formation and cell fate specification affect development. Here we identify a positive feedback loop between cell-cell contact duration, morphogen signaling and mesendoderm cell fate specification during zebrafish gastrulation. We show that long lasting cell-cell contacts enhance the competence of prechordal plate (ppl) progenitor cells to respond to Nodal signaling, required for proper ppl cell fate specification. We further show that Nodal signalling romotes ppl cell-cell contact duration, thereby generating an effective positive feedback loop between ppl cell-cell contact duration and cell fate specification. Finally, by using a combination of theoretical modeling and experimentation, we show that this feedback loop determines whether anterior axial mesendoderm cells become ppl progenitors or, instead, turn into endoderm progenitors. Our findings reveal that the gene regulatory networks leading to cell fate diversification within the developing embryo are controlled by the interdependent activities of cell-cell signaling and contact formation. acknowledgement: "Many people accompanied me during this trip: I would not have reached my destination nor \r\nenjoyed the travelling without them. First of all, thanks to CP. Thanks for making me part of \r\nyour team, always full of diverse, interesting and incredibly competent people and thanks for \r\nall the good science I witnessed \ and participated in. It has been a \r\nblast, an incredibly \r\nexciting \ one! Thanks to JLo, for teaching me how to master my pipettes and \ showing me \r\nthat science is a lot of fun. Many, many thanks to Gabby for teaching me basically everything \r\nabout zebrafish and being always there to advice, \ sugge\r\nst, support...and play fussball! \r\nThank you to Julien, for the critical eye on things, Pedro, for all the invaluable feedback and \r\nthe amazing kicker matches, and Keisuke, for showing me the light, and to the three of them \r\ntogether for all the good laughs we\r\nhad. My start in Vienna would \ have been a lot more \r\ndifficult without you guys. Also it would not \ have been possible without Elena and Inês: \r\nthanks for helping setting \ up this lab and for the dinners in Gugging. Thanks to Martin, for \r\nhelping me understand \r\nthe physics behind biology. Thanks to Philipp, \ for the interest and \r\nadvice, and to Michael, for the Viennise take on things. Thanks to Julia, for putting up with \r\nbeing our technician and becoming a friend in the process. And now to the newest members \r\nof th\r\ne lab. Thanks to Daniel for the enthusiasm and the neverending energy and for all your \r\nhelp over the years: thank you! To Jana, for showing me that one doesn’t give up, no matter \r\nwhat. \ To Shayan, for being such a motivated student. To Matt, for helping \ out\r\nwith coding \r\nand for finding punk solutions to data analysis problems. Thanks to all the members of the \r\nlab, Verena, Hitoshi, Silvia, Conny, Karla, Nicoletta, Zoltan, Peng, Benoit, Roland, Yuuta and \r\nFeyza, for the wonderful \ atmosphere in the lab. Many than\r\nks to Koni and Deborah: doing \r\nexperiments would have been much more difficult without your help. Special thanks to Katjia \r\nfor setting up an amazing imaging facility and for building the best \ team, Robert, Nasser, \r\nAnna and Doreen: thank you for putting up w\r\nith all the late sortings and for helping with all \r\nthe technical problems. Thanks to Eva, Verena and Matthias for keeping the fish happy. Big \r\nthanks to Harald Janovjak for being a present and helpful committee member over the years \r\nand \ to Patrick Lemaire f\r\nor the helpful insight and extremely interesting \ discussion we had \r\nabout the project. Also, this journey would not \ have been the same without all the friends \r\nthat I met in Dresden and then in Vienna: Daniele, Claire, Kuba, Steffi, Harold, Dejan, Irene, \r\nFab\r\nienne, Hande, Tiago, Marianne, Jon, Srdjan, Branca, Uli, Murat, Alex, Conny, Christoph, \r\nCaro, Simone, Barbara, Felipe, Dama, Jose, Hubert and many others that filled my days with \r\nfun and support. A special thank to my family, always close even if they are \r\nkilometers away. \r\nGrazie ai miei fratelli, Nunzio e William, \ e alla mia mamma, per essermi sempre vicini pur \r\nvivendo a chilometri di distanza. And, last but not least, thanks to Moritz, for putting up with \r\nthe crazy life of a scientist, the living apart for\r\nso long, never knowing when things are going \r\nto happen. Thanks for being a great partner and my number one fan!" alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Vanessa full_name: Barone, Vanessa id: 419EECCC-F248-11E8-B48F-1D18A9856A87 last_name: Barone orcid: 0000-0003-2676-3367 citation: ama: 'Barone V. Cell adhesion and cell fate: An effective feedback loop during zebrafish gastrulation. 2017. doi:10.15479/AT:ISTA:th_825' apa: 'Barone, V. (2017). Cell adhesion and cell fate: An effective feedback loop during zebrafish gastrulation. Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:th_825' chicago: 'Barone, Vanessa. “Cell Adhesion and Cell Fate: An Effective Feedback Loop during Zebrafish Gastrulation.” Institute of Science and Technology Austria, 2017. https://doi.org/10.15479/AT:ISTA:th_825.' ieee: 'V. Barone, “Cell adhesion and cell fate: An effective feedback loop during zebrafish gastrulation,” Institute of Science and Technology Austria, 2017.' ista: 'Barone V. 2017. Cell adhesion and cell fate: An effective feedback loop during zebrafish gastrulation. Institute of Science and Technology Austria.' mla: 'Barone, Vanessa. Cell Adhesion and Cell Fate: An Effective Feedback Loop during Zebrafish Gastrulation. Institute of Science and Technology Austria, 2017, doi:10.15479/AT:ISTA:th_825.' short: 'V. Barone, Cell Adhesion and Cell Fate: An Effective Feedback Loop during Zebrafish Gastrulation, Institute of Science and Technology Austria, 2017.' date_created: 2018-12-11T11:49:25Z date_published: 2017-03-01T00:00:00Z date_updated: 2023-09-27T14:16:45Z day: '01' ddc: - '570' - '590' degree_awarded: PhD department: - _id: CaHe doi: 10.15479/AT:ISTA:th_825 file: - access_level: closed checksum: 242f88c87f2cf267bf05049fa26a687b content_type: application/vnd.openxmlformats-officedocument.wordprocessingml.document creator: dernst date_created: 2019-04-05T08:36:52Z date_updated: 2020-07-14T12:48:16Z file_id: '6205' file_name: 2017_Barone_thesis_final.docx file_size: 14497822 relation: source_file - access_level: open_access checksum: ba5b0613ed8bade73a409acdd880fb8a content_type: application/pdf creator: dernst date_created: 2019-04-05T08:36:52Z date_updated: 2020-07-14T12:48:16Z file_id: '6206' file_name: 2017_Barone_thesis_.pdf file_size: 14995941 relation: main_file file_date_updated: 2020-07-14T12:48:16Z has_accepted_license: '1' language: - iso: eng month: '03' oa: 1 oa_version: Published Version page: '109' publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '6444' pubrep_id: '825' related_material: record: - id: '1100' relation: part_of_dissertation status: public - id: '1537' relation: part_of_dissertation status: public - id: '1912' relation: part_of_dissertation status: public - id: '2926' relation: part_of_dissertation status: public - id: '3246' relation: part_of_dissertation status: public - id: '676' relation: part_of_dissertation status: public - id: '735' relation: part_of_dissertation status: public status: public supervisor: - first_name: Carl-Philipp J full_name: Heisenberg, Carl-Philipp J id: 39427864-F248-11E8-B48F-1D18A9856A87 last_name: Heisenberg orcid: 0000-0002-0912-4566 title: 'Cell adhesion and cell fate: An effective feedback loop during zebrafish gastrulation' tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2017' ... --- _id: '819' abstract: - lang: eng text: 'Contagious diseases must transmit from infectious to susceptible hosts in order to reproduce. Whilst vectored pathogens can rely on intermediaries to find new hosts for them, many infectious pathogens require close contact or direct interaction between hosts for transmission. Hence, this means that conspecifics are often the main source of infection for most animals and so, in theory, animals should avoid conspecifics to reduce their risk of infection. Of course, in reality animals must interact with one another, as a bare minimum, to mate. However, being social provides many additional benefits and group living has become a taxonomically diverse and widespread trait. How then do social animals overcome the issue of increased disease? Over the last few decades, the social insects (ants, termites and some bees and wasps) have become a model system for studying disease in social animals. On paper, a social insect colony should be particularly susceptible to disease, given that they often contain thousands of potential hosts that are closely related and frequently interact, as well as exhibiting stable environmental conditions that encourage microbial growth. Yet, disease outbreaks appear to be rare and attempts to eradicate pest species using pathogens have failed time and again. Evolutionary biologists investigating this observation have discovered that the reduced disease susceptibility in social insects is, in part, due to collectively performed disease defences of the workers. These defences act like a “social immune system” for the colony, resulting in a per capita decrease in disease, termed social immunity. Our understanding of social immunity, and its importance in relation to the immunological defences of each insect, continues to grow, but there remain many open questions. In this thesis I have studied disease defence in garden ants. In the first data chapter, I use the invasive garden ant, Lasius neglectus, to investigate how colonies mitigate lethal infections and prevent them from spreading systemically. I find that ants have evolved ‘destructive disinfection’ – a behaviour that uses endogenously produced acidic poison to kill diseased brood and to prevent the pathogen from replicating. In the second experimental chapter, I continue to study the use of poison in invasive garden ant colonies, finding that it is sprayed prophylactically within the nest. However, this spraying has negative effects on developing pupae when they have had their cocoons artificially removed. Hence, I suggest that acidic nest sanitation may be maintaining larval cocoon spinning in this species. In the next experimental chapter, I investigated how colony founding black garden ant queens (Lasius niger) prevent disease when a co-foundress dies. I show that ant queens prophylactically perform undertaking behaviours, similar to those performed by the workers in mature nests. When a co-foundress was infected, these undertaking behaviours improved the survival of the healthy queen. In the final data chapter, I explored how immunocompetence (measured as antifungal activity) changes as incipient black garden ant colonies grow and mature, from the solitary queen phase to colonies with several hundred workers. Queen and worker antifungal activity varied throughout this time period, but despite social immunity, did not decrease as colonies matured. In addition to the above data chapters, this thesis includes two co-authored reviews. In the first, we examine the state of the art in the field of social immunity and how it might develop in the future. In the second, we identify several challenges and open questions in the study of disease defence in animals. We highlight how social insects offer a unique model to tackle some of these problems, as disease defence can be studied from the cell to the society. ' acknowledgement: "ERC FP7 programme (grant agreement no. 240371)\r\nI have been supremely spoilt to work in a lab with such good resources and I must thank the wonderful Cremer group technicians, Anna, Barbara, Eva and Florian, for all of their help and keeping the lab up and running. You guys will probably be the most missed once I realise just how much work you have been saving me! For the same reason, I must say a big Dzi ę kuj ę Ci to Wonder Woman Wanda, for her tireless efforts feeding my colonies and cranking out thousands of petri dishes and sugar tubes. Again, you will be sorely missed now that I will have to take this task on myself. Of course, I will be eternally indebted to Prof. Sylvia Cremer for taking me under her wing and being a constant source of guidance and inspiration. You have given me the perfect balance of independence and supervision. I cannot thank you enough for creating such a great working environment and allowing me the freedom to follow my own research questions. I have had so many exceptional opportunities – attending and presenting at conferences all over the world, inviting me to write the ARE with you, going to workshops in Panama and Switzerland, and even organising our own PhD course – that I often think I must have had the best PhD in the world. You have taught me so much and made me a scientist. I sincerely hope we get the chance to work together again in the future. Thank you for everything. I must also thank my PhD Committee, Daria Siekhaus and Jacobus “Koos” Boomsma, for being very supportive throughout the duration of my PhD. " alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Christopher full_name: Pull, Christopher id: 3C7F4840-F248-11E8-B48F-1D18A9856A87 last_name: Pull orcid: 0000-0003-1122-3982 citation: ama: Pull C. Disease defence in garden ants. 2017. doi:10.15479/AT:ISTA:th_861 apa: Pull, C. (2017). Disease defence in garden ants. Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:th_861 chicago: Pull, Christopher. “Disease Defence in Garden Ants.” Institute of Science and Technology Austria, 2017. https://doi.org/10.15479/AT:ISTA:th_861. ieee: C. Pull, “Disease defence in garden ants,” Institute of Science and Technology Austria, 2017. ista: Pull C. 2017. Disease defence in garden ants. Institute of Science and Technology Austria. mla: Pull, Christopher. Disease Defence in Garden Ants. Institute of Science and Technology Austria, 2017, doi:10.15479/AT:ISTA:th_861. short: C. Pull, Disease Defence in Garden Ants, Institute of Science and Technology Austria, 2017. date_created: 2018-12-11T11:48:40Z date_published: 2017-09-26T00:00:00Z date_updated: 2023-09-28T11:31:32Z day: '26' ddc: - '576' - '577' - '578' - '579' - '590' - '592' degree_awarded: PhD department: - _id: SyCr doi: 10.15479/AT:ISTA:th_861 file: - access_level: closed checksum: 4993cdd5382295758ecc3ecbd2a9aaff content_type: application/vnd.openxmlformats-officedocument.wordprocessingml.document creator: dernst date_created: 2019-04-05T07:53:04Z date_updated: 2020-07-14T12:48:09Z file_id: '6199' file_name: 2017_Thesis_Pull.docx file_size: 18580400 relation: source_file - access_level: open_access checksum: ee2e3ebb5b53c154c866f5b052b25153 content_type: application/pdf creator: dernst date_created: 2019-04-05T07:53:04Z date_updated: 2020-07-14T12:48:09Z file_id: '6200' file_name: 2017_Thesis_Pull.pdf file_size: 14400681 relation: main_file file_date_updated: 2020-07-14T12:48:09Z has_accepted_license: '1' language: - iso: eng month: '09' oa: 1 oa_version: Published Version page: '122' publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '6830' pubrep_id: '861' related_material: record: - id: '616' relation: part_of_dissertation status: public - id: '806' relation: part_of_dissertation status: public - id: '734' relation: part_of_dissertation status: public - id: '732' relation: part_of_dissertation status: public status: public supervisor: - first_name: Sylvia M full_name: Cremer, Sylvia M id: 2F64EC8C-F248-11E8-B48F-1D18A9856A87 last_name: Cremer orcid: 0000-0002-2193-3868 title: Disease defence in garden ants tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2017' ... --- _id: '839' abstract: - lang: eng text: 'This thesis describes a brittle fracture simulation method for visual effects applications. Building upon a symmetric Galerkin boundary element method, we first compute stress intensity factors following the theory of linear elastic fracture mechanics. We then use these stress intensities to simulate the motion of a propagating crack front at a significantly higher resolution than the overall deformation of the breaking object. Allowing for spatial variations of the material''s toughness during crack propagation produces visually realistic, highly-detailed fracture surfaces. Furthermore, we introduce approximations for stress intensities and crack opening displacements, resulting in both practical speed-up and theoretically superior runtime complexity compared to previous methods. While we choose a quasi-static approach to fracture mechanics, ignoring dynamic deformations, we also couple our fracture simulation framework to a standard rigid-body dynamics solver, enabling visual effects artists to simulate both large scale motion, as well as fracturing due to collision forces in a combined system. As fractures inside of an object grow, their geometry must be represented both in the coarse boundary element mesh, as well as at the desired fine output resolution. Using a boundary element method, we avoid complicated volumetric meshing operations. Instead we describe a simple set of surface meshing operations that allow us to progressively add cracks to the mesh of an object and still re-use all previously computed entries of the linear boundary element system matrix. On the high resolution level, we opt for an implicit surface representation. We then describe how to capture fracture surfaces during crack propagation, as well as separate the individual fragments resulting from the fracture process, based on this implicit representation. We show results obtained with our method, either solving the full boundary element system in every time step, or alternatively using our fast approximations. These results demonstrate that both of these methods perform well in basic test cases and produce realistic fracture surfaces. Furthermore we show that our fast approximations substantially out-perform the standard approach in more demanding scenarios. Finally, these two methods naturally combine, using the full solution while the problem size is manageably small and switching to the fast approximations later on. The resulting hybrid method gives the user a direct way to choose between speed and accuracy of the simulation. ' acknowledgement: "ERC H2020 programme (grant agreement no. 638176)\r\nFirst of all, let me thank my committee members, especially my supervisor, Chris\r\nWojtan, for supporting me throughout my PhD. Obviously, none of this work would\r\nhave been possible without you.\r\nFurthermore, Thank You to all the people who have contributed to this work in various\r\nways, in particular Martin Schanz and his group for providing and supporting the\r\nHyENA boundary element library, as well as Eder Miguel and Morten Bojsen-Hansen\r\nfor (repeatedly) proof reading and providing valuable suggestions during the writing\r\nof this thesis.\r\nI would also like to thank Bernd Bickel, and all the members – past and present – of his\r\nand Chris’ research groups at IST Austria for always providing honest and insightful\r\nfeedback throughout many joint group meetings, as well as Christopher Batty, Eitan\r\nGrinspun, and Fang Da for many insights into boundary element methods during our\r\ncollaboration.\r\nAs only virtual objects have been harmed in the process of creating this work, I would\r\nlike to acknowledge the Stanford scanning repository for providing the “Bunny” and\r\n“Armadillo” models, the AIM@SHAPE repository for “Pierre’s hand, watertight”, and\r\nS. Gainsbourg for the “Column” via Archive3D.net. Sorry for breaking these models\r\nin many different ways.\r\n" alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: David full_name: Hahn, David id: 357A6A66-F248-11E8-B48F-1D18A9856A87 last_name: Hahn citation: ama: Hahn D. Brittle fracture simulation with boundary elements for computer graphics. 2017. doi:10.15479/AT:ISTA:th_855 apa: Hahn, D. (2017). Brittle fracture simulation with boundary elements for computer graphics. Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:th_855 chicago: Hahn, David. “Brittle Fracture Simulation with Boundary Elements for Computer Graphics.” Institute of Science and Technology Austria, 2017. https://doi.org/10.15479/AT:ISTA:th_855. ieee: D. Hahn, “Brittle fracture simulation with boundary elements for computer graphics,” Institute of Science and Technology Austria, 2017. ista: Hahn D. 2017. Brittle fracture simulation with boundary elements for computer graphics. Institute of Science and Technology Austria. mla: Hahn, David. Brittle Fracture Simulation with Boundary Elements for Computer Graphics. Institute of Science and Technology Austria, 2017, doi:10.15479/AT:ISTA:th_855. short: D. Hahn, Brittle Fracture Simulation with Boundary Elements for Computer Graphics, Institute of Science and Technology Austria, 2017. date_created: 2018-12-11T11:48:47Z date_published: 2017-08-14T00:00:00Z date_updated: 2024-02-21T13:48:02Z day: '14' ddc: - '004' - '005' - '006' - '531' - '621' degree_awarded: PhD department: - _id: ChWo doi: 10.15479/AT:ISTA:th_855 ec_funded: 1 file: - access_level: open_access checksum: 6c1ae8c90bfaba5e089417fefbc4a272 content_type: application/pdf creator: system date_created: 2018-12-12T10:14:46Z date_updated: 2020-07-14T12:48:13Z file_id: '5100' file_name: IST-2017-855-v1+1_thesis_online_pdfA.pdf file_size: 14596191 relation: main_file - access_level: closed checksum: 421672f68d563b029869c5cf1713f919 content_type: application/zip creator: dernst date_created: 2019-04-05T08:40:30Z date_updated: 2020-07-14T12:48:13Z file_id: '6207' file_name: 2017_thesis_Hahn_source.zip file_size: 15060566 relation: source_file file_date_updated: 2020-07-14T12:48:13Z has_accepted_license: '1' language: - iso: eng license: https://creativecommons.org/licenses/by-sa/4.0/ month: '08' oa: 1 oa_version: Published Version page: '124' project: - _id: 2533E772-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '638176' name: Efficient Simulation of Natural Phenomena at Extremely Large Scales publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '6809' pubrep_id: '855' related_material: record: - id: '1362' relation: part_of_dissertation status: public - id: '1633' relation: part_of_dissertation status: public - id: '5568' relation: popular_science status: public status: public supervisor: - first_name: Christopher J full_name: Wojtan, Christopher J id: 3C61F1D2-F248-11E8-B48F-1D18A9856A87 last_name: Wojtan orcid: 0000-0001-6646-5546 title: Brittle fracture simulation with boundary elements for computer graphics tmp: image: /images/cc_by_sa.png legal_code_url: https://creativecommons.org/licenses/by-sa/4.0/legalcode name: Creative Commons Attribution-ShareAlike 4.0 International Public License (CC BY-SA 4.0) short: CC BY-SA (4.0) type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2017' ... --- _id: '1121' abstract: - lang: eng text: "Horizontal gene transfer (HGT), the lateral acquisition of genes across existing species\r\nboundaries, is a major evolutionary force shaping microbial genomes that facilitates\r\nadaptation to new environments as well as resistance to antimicrobial drugs. As such,\r\nunderstanding the mechanisms and constraints that determine the outcomes of HGT\r\nevents is crucial to understand the dynamics of HGT and to design better strategies to\r\novercome the challenges that originate from it.\r\nFollowing the insertion and expression of a newly transferred gene, the success of an\r\nHGT event will depend on the fitness effect it has on the recipient (host) cell. Therefore,\r\npredicting the impact of HGT on the genetic composition of a population critically\r\ndepends on the distribution of fitness effects (DFE) of horizontally transferred genes.\r\nHowever, to date, we have little knowledge of the DFE of newly transferred genes, and\r\nhence little is known about the shape and scale of this distribution.\r\nIt is particularly important to better understand the selective barriers that determine\r\nthe fitness effects of newly transferred genes. In spite of substantial bioinformatics\r\nefforts to identify horizontally transferred genes and selective barriers, a systematic\r\nexperimental approach to elucidate the roles of different selective barriers in defining\r\nthe fate of a transfer event has largely been absent. Similarly, although the fact that\r\nenvironment might alter the fitness effect of a horizontally transferred gene may seem\r\nobvious, little attention has been given to it in a systematic experimental manner.\r\nIn this study, we developed a systematic experimental approach that consists of\r\ntransferring 44 arbitrarily selected Salmonella typhimurium orthologous genes into an\r\nEscherichia coli host, and estimating the fitness effects of these transferred genes at a\r\nconstant expression level by performing competition assays against the wild type.\r\nIn chapter 2, we performed one-to-one competition assays between a mutant strain\r\ncarrying a transferred gene and the wild type strain. By using flow cytometry we\r\nestimated selection coefficients for the transferred genes with a precision level of 10-3,and obtained the DFE of horizontally transferred genes. We then investigated if these\r\nfitness effects could be predicted by any of the intrinsic properties of the genes, namely,\r\nfunctional category, degree of complexity (protein-protein interactions), GC content,\r\ncodon usage and length. Our analyses revealed that the functional category and length\r\nof the genes act as potential selective barriers. Finally, using the same procedure with\r\nthe endogenous E. coli orthologs of these 44 genes, we demonstrated that gene dosage is\r\nthe most prominent selective barrier to HGT.\r\nIn chapter 3, using the same set of genes we investigated the role of environment on the\r\nsuccess of HGT events. Under six different environments with different levels of stress\r\nwe performed more complex competition assays, where we mixed all 44 mutant strains\r\ncarrying transferred genes with the wild type strain. To estimate the fitness effects of\r\ngenes relative to wild type we used next generation sequencing. We found that the DFEs\r\nof horizontally transferred genes are highly dependent on the environment, with\r\nabundant gene–by-environment interactions. Furthermore, we demonstrated a\r\nrelationship between average fitness effect of a gene across all environments and its\r\nenvironmental variance, and thus its predictability. Finally, in spite of the fitness effects\r\nof genes being highly environment-dependent, we still observed a common shape of\r\nDFEs across all tested environments." acknowledgement: "This study was supported by European Research Council ERC CoG 2014 – EVOLHGT,\r\nunder the grant number 648440.\r\n\r\nIt is a pleasure to thank the many people who made this thesis possible.\r\nI would like to first thank my advisor, Jonathan Paul Bollback for providing guidance in\r\nall aspects of my life, encouragement, sound advice, and good teaching over the last six\r\nyears.\r\nI would also like to thank the members of my dissertation committee – Călin C. Guet\r\nand John F. Baines – not only for their time and guidance, but for their intellectual\r\ncontributions to my development as a scientist.\r\nI would like to thank Flavia Gama and Rodrigo Redondo who have taught me all the\r\nskills in the laboratory with their graciousness and friendship. Also special thanks to\r\nBollback group for their support and for providing a stimulating and fun environment:\r\nIsabella Tomanek, Fabienne Jesse, Claudia Igler, and Pavel Payne.\r\nJerneja Beslagic is not only an amazing assistant, she also has a smile brighter and\r\nwarmer than the sunshine, bringing happiness to every moment. Always keep your light\r\nNeja, I will miss our invaluable chatters a lot." alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Hande full_name: Acar, Hande id: 2DDF136A-F248-11E8-B48F-1D18A9856A87 last_name: Acar orcid: 0000-0003-1986-9753 citation: ama: Acar H. Selective barriers to horizontal gene transfer. 2016. apa: Acar, H. (2016). Selective barriers to horizontal gene transfer. Institute of Science and Technology Austria. chicago: Acar, Hande. “Selective Barriers to Horizontal Gene Transfer.” Institute of Science and Technology Austria, 2016. ieee: H. Acar, “Selective barriers to horizontal gene transfer,” Institute of Science and Technology Austria, 2016. ista: Acar H. 2016. Selective barriers to horizontal gene transfer. Institute of Science and Technology Austria. mla: Acar, Hande. Selective Barriers to Horizontal Gene Transfer. Institute of Science and Technology Austria, 2016. short: H. Acar, Selective Barriers to Horizontal Gene Transfer, Institute of Science and Technology Austria, 2016. date_created: 2018-12-11T11:50:16Z date_published: 2016-12-01T00:00:00Z date_updated: 2023-09-07T11:42:26Z day: '01' ddc: - '570' degree_awarded: PhD department: - _id: JoBo ec_funded: 1 file: - access_level: closed checksum: 94bbbc754c36115bf37f8fc11fad43c4 content_type: application/pdf creator: dernst date_created: 2019-08-13T11:17:50Z date_updated: 2019-08-13T11:17:50Z file_id: '6814' file_name: PhDThesis_HandeAcar_1230.pdf file_size: 3682711 relation: main_file - access_level: open_access checksum: 94bbbc754c36115bf37f8fc11fad43c4 content_type: application/pdf creator: dernst date_created: 2021-02-22T11:51:13Z date_updated: 2021-02-22T11:51:13Z file_id: '9184' file_name: 2016_Thesis_HandeAcar.pdf file_size: 3682711 relation: main_file success: 1 file_date_updated: 2021-02-22T11:51:13Z has_accepted_license: '1' language: - iso: eng month: '12' oa: 1 oa_version: Published Version page: '75' project: - _id: 2578D616-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '648440' name: Selective Barriers to Horizontal Gene Transfer publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '6239' status: public supervisor: - first_name: Jonathan P full_name: Bollback, Jonathan P id: 2C6FA9CC-F248-11E8-B48F-1D18A9856A87 last_name: Bollback orcid: 0000-0002-4624-4612 title: Selective barriers to horizontal gene transfer type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2016' ... --- _id: '1128' abstract: - lang: eng text: "The process of gene expression is central to the modern understanding of how cellular systems\r\nfunction. In this process, a special kind of regulatory proteins, called transcription factors,\r\nare important to determine how much protein is produced from a given gene. As biological\r\ninformation is transmitted from transcription factor concentration to mRNA levels to amounts of\r\nprotein, various sources of noise arise and pose limits to the fidelity of intracellular signaling.\r\nThis thesis concerns itself with several aspects of stochastic gene expression: (i) the mathematical\r\ndescription of complex promoters responsible for the stochastic production of biomolecules,\r\n(ii) fundamental limits to information processing the cell faces due to the interference from multiple\r\nfluctuating signals, (iii) how the presence of gene expression noise influences the evolution\r\nof regulatory sequences, (iv) and tools for the experimental study of origins and consequences\r\nof cell-cell heterogeneity, including an application to bacterial stress response systems." alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Georg full_name: Rieckh, Georg id: 34DA8BD6-F248-11E8-B48F-1D18A9856A87 last_name: Rieckh citation: ama: Rieckh G. Studying the complexities of transcriptional regulation. 2016. apa: Rieckh, G. (2016). Studying the complexities of transcriptional regulation. Institute of Science and Technology Austria. chicago: Rieckh, Georg. “Studying the Complexities of Transcriptional Regulation.” Institute of Science and Technology Austria, 2016. ieee: G. Rieckh, “Studying the complexities of transcriptional regulation,” Institute of Science and Technology Austria, 2016. ista: Rieckh G. 2016. Studying the complexities of transcriptional regulation. Institute of Science and Technology Austria. mla: Rieckh, Georg. Studying the Complexities of Transcriptional Regulation. Institute of Science and Technology Austria, 2016. short: G. Rieckh, Studying the Complexities of Transcriptional Regulation, Institute of Science and Technology Austria, 2016. date_created: 2018-12-11T11:50:18Z date_published: 2016-08-01T00:00:00Z date_updated: 2023-09-07T11:44:34Z day: '01' ddc: - '570' degree_awarded: PhD department: - _id: GaTk file: - access_level: closed checksum: ec453918c3bf8e6f460fd1156ef7b493 content_type: application/pdf creator: dernst date_created: 2019-08-13T11:46:25Z date_updated: 2019-08-13T11:46:25Z file_id: '6815' file_name: Thesis_Georg_Rieckh_w_signature_page.pdf file_size: 2614660 relation: main_file - access_level: open_access checksum: 51ae398166370d18fd22478b6365c4da content_type: application/pdf creator: dernst date_created: 2020-09-21T11:30:40Z date_updated: 2020-09-21T11:30:40Z file_id: '8542' file_name: Thesis_Georg_Rieckh.pdf file_size: 6096178 relation: main_file success: 1 file_date_updated: 2020-09-21T11:30:40Z has_accepted_license: '1' language: - iso: eng month: '08' oa: 1 oa_version: Published Version page: '114' publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '6232' status: public supervisor: - first_name: Gasper full_name: Tkacik, Gasper id: 3D494DCA-F248-11E8-B48F-1D18A9856A87 last_name: Tkacik orcid: 0000-0002-6699-1455 title: Studying the complexities of transcriptional regulation type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2016' ... --- _id: '1124' alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Maurizio full_name: Morri, Maurizio id: 4863116E-F248-11E8-B48F-1D18A9856A87 last_name: Morri citation: ama: Morri M. Optical functionalization of human class A orphan G-protein coupled receptors. 2016. apa: Morri, M. (2016). Optical functionalization of human class A orphan G-protein coupled receptors. Institute of Science and Technology Austria. chicago: Morri, Maurizio. “Optical Functionalization of Human Class A Orphan G-Protein Coupled Receptors.” Institute of Science and Technology Austria, 2016. ieee: M. Morri, “Optical functionalization of human class A orphan G-protein coupled receptors,” Institute of Science and Technology Austria, 2016. ista: Morri M. 2016. Optical functionalization of human class A orphan G-protein coupled receptors. Institute of Science and Technology Austria. mla: Morri, Maurizio. Optical Functionalization of Human Class A Orphan G-Protein Coupled Receptors. Institute of Science and Technology Austria, 2016. short: M. Morri, Optical Functionalization of Human Class A Orphan G-Protein Coupled Receptors, Institute of Science and Technology Austria, 2016. date_created: 2018-12-11T11:50:17Z date_published: 2016-03-01T00:00:00Z date_updated: 2023-09-07T11:43:03Z day: '01' ddc: - '570' degree_awarded: PhD department: - _id: HaJa file: - access_level: closed checksum: b439803ac0827cdddd56562a54e3b53b content_type: application/pdf creator: dernst date_created: 2019-08-13T10:50:00Z date_updated: 2019-08-13T10:50:00Z file_id: '6812' file_name: MORRI_PhD_thesis_FINALPLUSSIGNATURES (2).pdf file_size: 4785167 relation: main_file - access_level: open_access checksum: dd4136247fe472e7d47880ec68ac8de0 content_type: application/pdf creator: dernst date_created: 2021-02-22T11:42:06Z date_updated: 2021-02-22T11:42:06Z file_id: '9180' file_name: 2016_MORRI_Thesis.pdf file_size: 4495669 relation: main_file success: 1 file_date_updated: 2021-02-22T11:42:06Z has_accepted_license: '1' language: - iso: eng month: '03' oa: 1 oa_version: Published Version page: '129' publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '6236' status: public supervisor: - first_name: Harald L full_name: Janovjak, Harald L id: 33BA6C30-F248-11E8-B48F-1D18A9856A87 last_name: Janovjak orcid: 0000-0002-8023-9315 title: Optical functionalization of human class A orphan G-protein coupled receptors type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2016' ... --- _id: '1129' abstract: - lang: eng text: "Directed cell migration is a hallmark feature, present in almost all multi-cellular\r\norganisms. Despite its importance, basic questions regarding force transduction\r\nor directional sensing are still heavily investigated. Directed migration of cells\r\nguided by immobilized guidance cues - haptotaxis - occurs in key-processes,\r\nsuch as embryonic development and immunity (Middleton et al., 1997; Nguyen\r\net al., 2000; Thiery, 1984; Weber et al., 2013). Immobilized guidance cues\r\ncomprise adhesive ligands, such as collagen and fibronectin (Barczyk et al.,\r\n2009), or chemokines - the main guidance cues for migratory leukocytes\r\n(Middleton et al., 1997; Weber et al., 2013). While adhesive ligands serve as\r\nattachment sites guiding cell migration (Carter, 1965), chemokines instruct\r\nhaptotactic migration by inducing adhesion to adhesive ligands and directional\r\nguidance (Rot and Andrian, 2004; Schumann et al., 2010). Quantitative analysis\r\nof the cellular response to immobilized guidance cues requires in vitro assays\r\nthat foster cell migration, offer accurate control of the immobilized cues on a\r\nsubcellular scale and in the ideal case closely reproduce in vivo conditions. The\r\nexploration of haptotactic cell migration through design and employment of such\r\nassays represents the main focus of this work.\r\nDendritic cells (DCs) are leukocytes, which after encountering danger\r\nsignals such as pathogens in peripheral organs instruct naïve T-cells and\r\nconsequently the adaptive immune response in the lymph node (Mellman and\r\nSteinman, 2001). To reach the lymph node from the periphery, DCs follow\r\nhaptotactic gradients of the chemokine CCL21 towards lymphatic vessels\r\n(Weber et al., 2013). Questions about how DCs interpret haptotactic CCL21\r\ngradients have not yet been addressed. The main reason for this is the lack of\r\nan assay that offers diverse haptotactic environments, hence allowing the study\r\nof DC migration as a response to different signals of immobilized guidance cue.\r\nIn this work, we developed an in vitro assay that enables us to\r\nquantitatively assess DC haptotaxis, by combining precisely controllable\r\nchemokine photo-patterning with physically confining migration conditions. With this tool at hand, we studied the influence of CCL21 gradient properties and\r\nconcentration on DC haptotaxis. We found that haptotactic gradient sensing\r\ndepends on the absolute CCL21 concentration in combination with the local\r\nsteepness of the gradient. Our analysis suggests that the directionality of\r\nmigrating DCs is governed by the signal-to-noise ratio of CCL21 binding to its\r\nreceptor CCR7. Moreover, the haptotactic CCL21 gradient formed in vivo\r\nprovides an optimal shape for DCs to recognize haptotactic guidance cue.\r\nBy reconstitution of the CCL21 gradient in vitro we were also able to\r\nstudy the influence of CCR7 signal termination on DC haptotaxis. To this end,\r\nwe used DCs lacking the G-protein coupled receptor kinase GRK6, which is\r\nresponsible for CCL21 induced CCR7 receptor phosphorylation and\r\ndesensitization (Zidar et al., 2009). We found that CCR7 desensitization by\r\nGRK6 is crucial for maintenance of haptotactic CCL21 gradient sensing in vitro\r\nand confirm those observations in vivo.\r\nIn the context of the organism, immobilized haptotactic guidance cues\r\noften coincide and compete with soluble chemotactic guidance cues. During\r\nwound healing, fibroblasts are exposed and influenced by adhesive cues and\r\nsoluble factors at the same time (Wu et al., 2012; Wynn, 2008). Similarly,\r\nmigrating DCs are exposed to both, soluble chemokines (CCL19 and truncated\r\nCCL21) inducing chemotactic behavior as well as the immobilized CCL21. To\r\nquantitatively assess these complex coinciding immobilized and soluble\r\nguidance cues, we implemented our chemokine photo-patterning technique in a\r\nmicrofluidic system allowing for chemotactic gradient generation. To validate\r\nthe assay, we observed DC migration in competing CCL19/CCL21\r\nenvironments.\r\nAdhesiveness guided haptotaxis has been studied intensively over the\r\nlast century. However, quantitative studies leading to conceptual models are\r\nlargely missing, again due to the lack of a precisely controllable in vitro assay. A\r\nrequirement for such an in vitro assay is that it must prevent any uncontrolled\r\ncell adhesion. This can be accomplished by stable passivation of the surface. In\r\naddition, controlled adhesion must be sustainable, quantifiable and dose\r\ndependent in order to create homogenous gradients. Therefore, we developed a novel covalent photo-patterning technique satisfying all these needs. In\r\ncombination with a sustainable poly-vinyl alcohol (PVA) surface coating we\r\nwere able to generate gradients of adhesive cue to direct cell migration. This\r\napproach allowed us to characterize the haptotactic migratory behavior of\r\nzebrafish keratocytes in vitro. Furthermore, defined patterns of adhesive cue\r\nallowed us to control for cell shape and growth on a subcellular scale." acknowledged_ssus: - _id: Bio - _id: PreCl - _id: LifeSc acknowledgement: "First, I would like to thank Michael Sixt for being a great supervisor, mentor and\r\nscientist. I highly appreciate his guidance and continued support. Furthermore, I\r\nam very grateful that he gave me the exceptional opportunity to pursue many\r\nideas of which some managed to be included in this thesis.\r\nI owe sincere thanks to the members of my PhD thesis committee, Daria\r\nSiekhaus, Daniel Legler and Harald Janovjak. Especially I would like to thank\r\nDaria for her advice and encouragement during our regular progress meetings.\r\nI also want to thank the team and fellows of the Boehringer Ingelheim Fond\r\n(BIF) PhD Fellowship for amazing and inspiring meetings and the BIF for\r\nfinancial support.\r\nImportant factors for the success of this thesis were the warm, creative\r\nand helpful atmosphere as well as the team spirit of the whole Sixt Lab.\r\nTherefore I would like to thank my current and former colleagues Frank Assen,\r\nMarkus Brown, Ingrid de Vries, Michelle Duggan, Alexander Eichner, Miroslav\r\nHons, Eva Kiermaier, Aglaja Kopf, Alexander Leithner, Christine Moussion, Jan\r\nMüller, Maria Nemethova, Jörg Renkawitz, Anne Reversat, Kari Vaahtomeri,\r\nMichele Weber and Stefan Wieser. We had an amazing time with many\r\nlegendary evenings and events. Along these lines I want to thank the in vitro\r\ncrew of the lab, Jörg, Anne and Alex, for lots of ideas and productive\r\ndiscussions. I am sure, some day we will reveal the secret of the ‘splodge’.\r\nI want to thank the members of the Heisenberg Lab for a great time and\r\nthrilling kicker matches. In this regard I especially want to thank Maurizio\r\n‘Gnocci’ Monti, Gabriel Krens, Alex Eichner, Martin Behrndt, Vanessa Barone,Philipp Schmalhorst, Michael Smutny, Daniel Capek, Anne Reversat, Eva\r\nKiermaier, Frank Assen and Jan Müller for wonderful after-lunch matches.\r\nI would not have been able to analyze the thousands of cell trajectories\r\nand probably hundreds of thousands of mouse clicks without the productive\r\ncollaboration with Veronika Bierbaum and Tobias Bollenbach. Thanks Vroni for\r\ncountless meetings, discussions and graphs and of course for proofreading and\r\nadvice for this thesis. For proofreading I also want to thank Evi, Jörg, Jack and\r\nAnne.\r\nI would like to acknowledge Matthias Mehling for a very productive\r\ncollaboration and for introducing me into the wild world of microfluidics. Jack\r\nMerrin, for countless wafers, PDMS coated coverslips and help with anything\r\nmicro-fabrication related. And Maria Nemethova for establishing the ‘click’\r\npatterning approach with me. Without her it still would be just one of the ideas…\r\nMany thanks to Ekaterina Papusheva, Robert Hauschild, Doreen Milius\r\nand Nasser Darwish from the Bioimaging Facility as well as the Preclinical and\r\nthe Life Science facilities of IST Austria for excellent technical support. At this\r\npoint I especially want to thank Robert for countless image analyses and\r\ntechnical ideas. Always interested and creative he played an essential role in all\r\nof my projects.\r\nAdditionally I want to thank Ingrid and Gabby for welcoming me warmly\r\nwhen I first started at IST, for scientific and especially mental support in all\r\nthose years, countless coffee sessions and Heurigen evenings. #BioimagingFacility #LifeScienceFacility #PreClinicalFacility" alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Jan full_name: Schwarz, Jan id: 346C1EC6-F248-11E8-B48F-1D18A9856A87 last_name: Schwarz citation: ama: Schwarz J. Quantitative analysis of haptotactic cell migration. 2016. apa: Schwarz, J. (2016). Quantitative analysis of haptotactic cell migration. Institute of Science and Technology Austria. chicago: Schwarz, Jan. “Quantitative Analysis of Haptotactic Cell Migration.” Institute of Science and Technology Austria, 2016. ieee: J. Schwarz, “Quantitative analysis of haptotactic cell migration,” Institute of Science and Technology Austria, 2016. ista: Schwarz J. 2016. Quantitative analysis of haptotactic cell migration. Institute of Science and Technology Austria. mla: Schwarz, Jan. Quantitative Analysis of Haptotactic Cell Migration. Institute of Science and Technology Austria, 2016. short: J. Schwarz, Quantitative Analysis of Haptotactic Cell Migration, Institute of Science and Technology Austria, 2016. date_created: 2018-12-11T11:50:18Z date_published: 2016-07-01T00:00:00Z date_updated: 2023-09-07T11:54:33Z day: '01' ddc: - '570' degree_awarded: PhD department: - _id: MiSi file: - access_level: closed checksum: e3cd6b28f9c5cccb8891855565a2dade content_type: application/pdf creator: dernst date_created: 2019-08-13T10:55:35Z date_updated: 2019-08-13T10:55:35Z file_id: '6813' file_name: Thesis_JSchwarz_final.pdf file_size: 32044069 relation: main_file - access_level: open_access checksum: c3dbe219acf87eed2f46d21d5cca00de content_type: application/pdf creator: dernst date_created: 2021-02-22T11:43:14Z date_updated: 2021-02-22T11:43:14Z file_id: '9181' file_name: 2016_Thesis_JSchwarz.pdf file_size: 8396717 relation: main_file success: 1 file_date_updated: 2021-02-22T11:43:14Z has_accepted_license: '1' language: - iso: eng month: '07' oa: 1 oa_version: Published Version page: '178' publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '6231' status: public supervisor: - first_name: Michael K full_name: Sixt, Michael K id: 41E9FBEA-F248-11E8-B48F-1D18A9856A87 last_name: Sixt orcid: 0000-0002-6620-9179 title: Quantitative analysis of haptotactic cell migration type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2016' ... --- _id: '1126' abstract: - lang: eng text: "Traditionally machine learning has been focusing on the problem of solving a single\r\ntask in isolation. While being quite well understood, this approach disregards an\r\nimportant aspect of human learning: when facing a new problem, humans are able to\r\nexploit knowledge acquired from previously learned tasks. Intuitively, access to several\r\nproblems simultaneously or sequentially could also be advantageous for a machine\r\nlearning system, especially if these tasks are closely related. Indeed, results of many\r\nempirical studies have provided justification for this intuition. However, theoretical\r\njustifications of this idea are rather limited.\r\nThe focus of this thesis is to expand the understanding of potential benefits of information\r\ntransfer between several related learning problems. We provide theoretical\r\nanalysis for three scenarios of multi-task learning - multiple kernel learning, sequential\r\nlearning and active task selection. We also provide a PAC-Bayesian perspective on\r\nlifelong learning and investigate how the task generation process influences the generalization\r\nguarantees in this scenario. In addition, we show how some of the obtained\r\ntheoretical results can be used to derive principled multi-task and lifelong learning\r\nalgorithms and illustrate their performance on various synthetic and real-world datasets." acknowledgement: "First and foremost I would like to express my gratitude to my supervisor, Christoph\r\nLampert. Thank you for your patience in teaching me all aspects of doing research\r\n(including English grammar), for your trust in my capabilities and endless support. Thank\r\nyou for granting me freedom in my research and, at the same time, having time and\r\nhelping me cope with the consequences whenever I needed it. Thank you for creating\r\nan excellent atmosphere in the group, it was a great pleasure and honor to be a part of\r\nit. There could not have been a better and more inspiring adviser and mentor.\r\nI thank Shai Ben-David for welcoming me into his group at the University of Waterloo,\r\nfor inspiring discussions and support. It was a great pleasure to work together. I am\r\nalso thankful to Ruth Urner for hosting me at the Max-Planck Institute Tübingen, for the\r\nfruitful collaboration and for taking care of me during that not-so-sunny month of May.\r\nI thank Jan Maas for kindly joining my thesis committee despite the short notice and\r\nproviding me with insightful comments.\r\nI would like to thank my colleagues for their support, entertaining conversations and\r\nendless table soccer games we shared together: Georg, Jan, Amelie and Emilie, Michal\r\nand Alex, Alex K. and Alex Z., Thomas, Sameh, Vlad, Mayu, Nathaniel, Silvester, Neel,\r\nCsaba, Vladimir, Morten. Thank you, Mabel and Ram, for the wonderful time we spent\r\ntogether. I am thankful to Shrinu and Samira for taking care of me during my stay at the\r\nUniversity of Waterloo. Special thanks to Viktoriia for her never-ending optimism and for\r\nbeing so inspiring and supportive, especially at the beginning of my PhD journey.\r\nThanks to IST administration, in particular, Vlad and Elisabeth for shielding me from\r\nmost of the bureaucratic paperwork.\r\n\r\nThis dissertation would not have been possible without funding from the European\r\nResearch Council under the European Union's Seventh Framework Programme\r\n(FP7/2007-2013)/ERC grant agreement no 308036." alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Anastasia full_name: Pentina, Anastasia id: 42E87FC6-F248-11E8-B48F-1D18A9856A87 last_name: Pentina citation: ama: Pentina A. Theoretical foundations of multi-task lifelong learning. 2016. doi:10.15479/AT:ISTA:TH_776 apa: Pentina, A. (2016). Theoretical foundations of multi-task lifelong learning. Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:TH_776 chicago: Pentina, Anastasia. “Theoretical Foundations of Multi-Task Lifelong Learning.” Institute of Science and Technology Austria, 2016. https://doi.org/10.15479/AT:ISTA:TH_776. ieee: A. Pentina, “Theoretical foundations of multi-task lifelong learning,” Institute of Science and Technology Austria, 2016. ista: Pentina A. 2016. Theoretical foundations of multi-task lifelong learning. Institute of Science and Technology Austria. mla: Pentina, Anastasia. Theoretical Foundations of Multi-Task Lifelong Learning. Institute of Science and Technology Austria, 2016, doi:10.15479/AT:ISTA:TH_776. short: A. Pentina, Theoretical Foundations of Multi-Task Lifelong Learning, Institute of Science and Technology Austria, 2016. date_created: 2018-12-11T11:50:17Z date_published: 2016-11-01T00:00:00Z date_updated: 2023-09-07T11:52:03Z day: '01' ddc: - '006' degree_awarded: PhD department: - _id: ChLa doi: 10.15479/AT:ISTA:TH_776 ec_funded: 1 file: - access_level: open_access content_type: application/pdf creator: system date_created: 2018-12-12T10:14:07Z date_updated: 2018-12-12T10:14:07Z file_id: '5056' file_name: IST-2017-776-v1+1_Pentina_Thesis_2016.pdf file_size: 2140062 relation: main_file file_date_updated: 2018-12-12T10:14:07Z has_accepted_license: '1' language: - iso: eng month: '11' oa: 1 oa_version: Published Version page: '127' project: - _id: 2532554C-B435-11E9-9278-68D0E5697425 call_identifier: FP7 grant_number: '308036' name: Lifelong Learning of Visual Scene Understanding publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '6234' pubrep_id: '776' status: public supervisor: - first_name: Christoph full_name: Lampert, Christoph id: 40C20FD2-F248-11E8-B48F-1D18A9856A87 last_name: Lampert orcid: 0000-0001-8622-7887 title: Theoretical foundations of multi-task lifelong learning type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2016' ... --- _id: '1397' abstract: - lang: eng text: 'We study partially observable Markov decision processes (POMDPs) with objectives used in verification and artificial intelligence. The qualitative analysis problem given a POMDP and an objective asks whether there is a strategy (policy) to ensure that the objective is satisfied almost surely (with probability 1), resp. with positive probability (with probability greater than 0). For POMDPs with limit-average payoff, where a reward value in the interval [0,1] is associated to every transition, and the payoff of an infinite path is the long-run average of the rewards, we consider two types of path constraints: (i) a quantitative limit-average constraint defines the set of paths where the payoff is at least a given threshold L1 = 1. Our main results for qualitative limit-average constraint under almost-sure winning are as follows: (i) the problem of deciding the existence of a finite-memory controller is EXPTIME-complete; and (ii) the problem of deciding the existence of an infinite-memory controller is undecidable. For quantitative limit-average constraints we show that the problem of deciding the existence of a finite-memory controller is undecidable. We present a prototype implementation of our EXPTIME algorithm. For POMDPs with w-regular conditions specified as parity objectives, while the qualitative analysis problems are known to be undecidable even for very special case of parity objectives, we establish decidability (with optimal complexity) of the qualitative analysis problems for POMDPs with parity objectives under finite-memory strategies. We establish optimal (exponential) memory bounds and EXPTIME-completeness of the qualitative analysis problems under finite-memory strategies for POMDPs with parity objectives. Based on our theoretical algorithms we also present a practical approach, where we design heuristics to deal with the exponential complexity, and have applied our implementation on a number of well-known POMDP examples for robotics applications. For POMDPs with a set of target states and an integer cost associated with every transition, we study the optimization objective that asks to minimize the expected total cost of reaching a state in the target set, while ensuring that the target set is reached almost surely. We show that for general integer costs approximating the optimal cost is undecidable. For positive costs, our results are as follows: (i) we establish matching lower and upper bounds for the optimal cost, both double and exponential in the POMDP state space size; (ii) we show that the problem of approximating the optimal cost is decidable and present approximation algorithms that extend existing algorithms for POMDPs with finite-horizon objectives. We show experimentally that it performs well in many examples of interest. We study more deeply the problem of almost-sure reachability, where given a set of target states, the question is to decide whether there is a strategy to ensure that the target set is reached almost surely. While in general the problem EXPTIME-complete, in many practical cases strategies with a small amount of memory suffice. Moreover, the existing solution to the problem is explicit, which first requires to construct explicitly an exponential reduction to a belief-support MDP. We first study the existence of observation-stationary strategies, which is NP-complete, and then small-memory strategies. We present a symbolic algorithm by an efficient encoding to SAT and using a SAT solver for the problem. We report experimental results demonstrating the scalability of our symbolic (SAT-based) approach. Decentralized POMDPs (DEC-POMDPs) extend POMDPs to a multi-agent setting, where several agents operate in an uncertain environment independently to achieve a joint objective. In this work we consider Goal DEC-POMDPs, where given a set of target states, the objective is to ensure that the target set is reached with minimal cost. We consider the indefinite-horizon (infinite-horizon with either discounted-sum, or undiscounted-sum, where absorbing goal states have zero-cost) problem. We present a new and novel method to solve the problem that extends methods for finite-horizon DEC-POMDPs and the real-time dynamic programming approach for POMDPs. We present experimental results on several examples, and show that our approach presents promising results. In the end we present a short summary of a few other results related to verification of MDPs and POMDPs.' alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Martin full_name: Chmelik, Martin id: 3624234E-F248-11E8-B48F-1D18A9856A87 last_name: Chmelik citation: ama: Chmelik M. Algorithms for partially observable markov decision processes. 2016. apa: Chmelik, M. (2016). Algorithms for partially observable markov decision processes. Institute of Science and Technology Austria. chicago: Chmelik, Martin. “Algorithms for Partially Observable Markov Decision Processes.” Institute of Science and Technology Austria, 2016. ieee: M. Chmelik, “Algorithms for partially observable markov decision processes,” Institute of Science and Technology Austria, 2016. ista: Chmelik M. 2016. Algorithms for partially observable markov decision processes. Institute of Science and Technology Austria. mla: Chmelik, Martin. Algorithms for Partially Observable Markov Decision Processes. Institute of Science and Technology Austria, 2016. short: M. Chmelik, Algorithms for Partially Observable Markov Decision Processes, Institute of Science and Technology Austria, 2016. date_created: 2018-12-11T11:51:47Z date_published: 2016-02-01T00:00:00Z date_updated: 2023-09-07T11:54:58Z day: '01' degree_awarded: PhD department: - _id: KrCh language: - iso: eng month: '02' oa_version: None page: '232' publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '5810' status: public supervisor: - first_name: Krishnendu full_name: Chatterjee, Krishnendu id: 2E5DCA20-F248-11E8-B48F-1D18A9856A87 last_name: Chatterjee orcid: 0000-0002-4561-241X title: Algorithms for partially observable markov decision processes type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2016' ... --- _id: '1123' abstract: - lang: eng text: "Motivated by topological Tverberg-type problems in topological combinatorics and by classical\r\nresults about embeddings (maps without double points), we study the question whether a finite\r\nsimplicial complex K can be mapped into Rd without triple, quadruple, or, more generally, r-fold points (image points with at least r distinct preimages), for a given multiplicity r ≤ 2. In particular, we are interested in maps f : K → Rd that have no global r -fold intersection points, i.e., no r -fold points with preimages in r pairwise disjoint simplices of K , and we seek necessary and sufficient conditions for the existence of such maps.\r\n\r\nWe present higher-multiplicity analogues of several classical results for embeddings, in particular of the completeness of the Van Kampen obstruction \ for embeddability of k -dimensional\r\ncomplexes into R2k , k ≥ 3. Speciffically, we show that under suitable restrictions on the dimensions(viz., if dimK = (r ≥ 1)k and d = rk \\ for some k ≥ 3), a well-known deleted product criterion (DPC ) is not only necessary but also sufficient for the existence of maps without global r -fold points. Our main technical tool is a higher-multiplicity version of the classical Whitney trick , by which pairs of isolated r -fold points of opposite sign can be eliminated by local modiffications of the map, assuming codimension d – dimK ≥ 3.\r\n\r\nAn important guiding idea for our work was that suffciency of the DPC, together with an old\r\nresult of Özaydin's on the existence of equivariant maps, might yield an approach to disproving the remaining open cases of the the long-standing topological Tverberg conjecture , i.e., to construct maps from the N -simplex σN to Rd without r-Tverberg points when r not a prime power and\r\nN = (d + 1)(r – 1). Unfortunately, our proof of the sufficiency of the DPC requires codimension d – dimK ≥ 3, which is not satisfied for K = σN .\r\n\r\nIn 2015, Frick [16] found a very elegant way to overcome this \\codimension 3 obstacle" and\r\nto construct the first counterexamples to the topological Tverberg conjecture for all parameters(d; r ) with d ≥ 3r + 1 and r not a prime power, by a reduction1 to a suitable lower-dimensional skeleton, for which the codimension 3 restriction is satisfied and maps without r -Tverberg points exist by Özaydin's result and sufficiency of the DPC.\r\n\r\nIn this thesis, we present a different construction (which does not use the constraint method) that yields counterexamples for d ≥ 3r , r not a prime power. " acknowledgement: "Foremost, I would like to thank Uli Wagner for introducing me to the exciting interface between\r\ntopology and combinatorics, and for our subsequent years of fruitful collaboration.\r\nIn our creative endeavors to eliminate intersection points, we had the chance to be joined later\r\nby Sergey Avvakumov and Arkadiy Skopenkov, which led us to new surprises in dimension 12.\r\nMy stay at EPFL and IST Austria was made very agreeable thanks to all these wonderful\r\npeople: Cyril Becker, Marek Filakovsky, Peter Franek, Radoslav Fulek, Peter Gazi, Kristof Huszar,\r\nMarek Krcal, Zuzana Masarova, Arnaud de Mesmay, Filip Moric, Michal Rybar, Martin Tancer,\r\nand Stephan Zhechev.\r\nFinally, I would like to thank my thesis committee Herbert Edelsbrunner and Roman Karasev\r\nfor their careful reading of the present manuscript and for the many improvements they suggested." alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Isaac full_name: Mabillard, Isaac id: 32BF9DAA-F248-11E8-B48F-1D18A9856A87 last_name: Mabillard citation: ama: 'Mabillard I. Eliminating higher-multiplicity intersections: an r-fold Whitney trick for the topological Tverberg conjecture. 2016.' apa: 'Mabillard, I. (2016). Eliminating higher-multiplicity intersections: an r-fold Whitney trick for the topological Tverberg conjecture. Institute of Science and Technology Austria.' chicago: 'Mabillard, Isaac. “Eliminating Higher-Multiplicity Intersections: An r-Fold Whitney Trick for the Topological Tverberg Conjecture.” Institute of Science and Technology Austria, 2016.' ieee: 'I. Mabillard, “Eliminating higher-multiplicity intersections: an r-fold Whitney trick for the topological Tverberg conjecture,” Institute of Science and Technology Austria, 2016.' ista: 'Mabillard I. 2016. Eliminating higher-multiplicity intersections: an r-fold Whitney trick for the topological Tverberg conjecture. Institute of Science and Technology Austria.' mla: 'Mabillard, Isaac. Eliminating Higher-Multiplicity Intersections: An r-Fold Whitney Trick for the Topological Tverberg Conjecture. Institute of Science and Technology Austria, 2016.' short: 'I. Mabillard, Eliminating Higher-Multiplicity Intersections: An r-Fold Whitney Trick for the Topological Tverberg Conjecture, Institute of Science and Technology Austria, 2016.' date_created: 2018-12-11T11:50:16Z date_published: 2016-08-01T00:00:00Z date_updated: 2023-09-07T11:56:28Z day: '01' ddc: - '500' degree_awarded: PhD department: - _id: UlWa file: - access_level: closed checksum: 2d140cc924cd1b764544906fc22684ef content_type: application/pdf creator: dernst date_created: 2019-08-13T08:45:27Z date_updated: 2019-08-13T08:45:27Z file_id: '6809' file_name: Thesis_final version_Mabillard_w_signature_page.pdf file_size: 2227916 relation: main_file - access_level: open_access checksum: 2d140cc924cd1b764544906fc22684ef content_type: application/pdf creator: dernst date_created: 2021-02-22T11:36:34Z date_updated: 2021-02-22T11:36:34Z file_id: '9178' file_name: 2016_Mabillard_Thesis.pdf file_size: 2227916 relation: main_file success: 1 file_date_updated: 2021-02-22T11:36:34Z has_accepted_license: '1' language: - iso: eng month: '08' oa: 1 oa_version: Published Version page: '55' publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '6237' related_material: record: - id: '2159' relation: part_of_dissertation status: public status: public supervisor: - first_name: Uli full_name: Wagner, Uli id: 36690CA2-F248-11E8-B48F-1D18A9856A87 last_name: Wagner orcid: 0000-0002-1494-0568 title: 'Eliminating higher-multiplicity intersections: an r-fold Whitney trick for the topological Tverberg conjecture' type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2016' ... --- _id: '1396' abstract: - lang: eng text: CA3 pyramidal neurons are thought to pay a key role in memory storage and pattern completion by activity-dependent synaptic plasticity between CA3-CA3 recurrent excitatory synapses. To examine the induction rules of synaptic plasticity at CA3-CA3 synapses, we performed whole-cell patch-clamp recordings in acute hippocampal slices from rats (postnatal 21-24 days) at room temperature. Compound excitatory postsynaptic potentials (ESPSs) were recorded by tract stimulation in stratum oriens in the presence of 10 µM gabazine. High-frequency stimulation (HFS) induced N-methyl-D-aspartate (NMDA) receptor-dependent long-term potentiation (LTP). Although LTP by HFS did not requier postsynaptic spikes, it was blocked by Na+-channel blockers suggesting that local active processes (e.g.) dendritic spikes) may contribute to LTP induction without requirement of a somatic action potential (AP). We next examined the properties of spike timing-dependent plasticity (STDP) at CA3-CA3 synapses. Unexpectedly, low-frequency pairing of EPSPs and backpropagated action potentialy (bAPs) induced LTP, independent of temporal order. The STDP curve was symmetric and broad, with a half-width of ~150 ms. Consistent with these specific STDP induction properties, post-presynaptic sequences led to a supralinear summation of spine [Ca2+] transients. Furthermore, in autoassociative network models, storage and recall was substantially more robust with symmetric than with asymmetric STDP rules. In conclusion, we found associative forms of LTP at CA3-CA3 recurrent collateral synapses with distinct induction rules. LTP induced by HFS may be associated with dendritic spikes. In contrast, low frequency pairing of pre- and postsynaptic activity induced LTP only if EPSP-AP were temporally very close. Together, these induction mechanisms of synaptiic plasticity may contribute to memory storage in the CA3-CA3 microcircuit at different ranges of activity. alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Rajiv Kumar full_name: Mishra, Rajiv Kumar id: 46CB58F2-F248-11E8-B48F-1D18A9856A87 last_name: Mishra citation: ama: Mishra RK. Synaptic plasticity rules at CA3-CA3 recurrent synapses in hippocampus. 2016. apa: Mishra, R. K. (2016). Synaptic plasticity rules at CA3-CA3 recurrent synapses in hippocampus. Institute of Science and Technology Austria. chicago: Mishra, Rajiv Kumar. “Synaptic Plasticity Rules at CA3-CA3 Recurrent Synapses in Hippocampus.” Institute of Science and Technology Austria, 2016. ieee: R. K. Mishra, “Synaptic plasticity rules at CA3-CA3 recurrent synapses in hippocampus,” Institute of Science and Technology Austria, 2016. ista: Mishra RK. 2016. Synaptic plasticity rules at CA3-CA3 recurrent synapses in hippocampus. Institute of Science and Technology Austria. mla: Mishra, Rajiv Kumar. Synaptic Plasticity Rules at CA3-CA3 Recurrent Synapses in Hippocampus. Institute of Science and Technology Austria, 2016. short: R.K. Mishra, Synaptic Plasticity Rules at CA3-CA3 Recurrent Synapses in Hippocampus, Institute of Science and Technology Austria, 2016. date_created: 2018-12-11T11:51:46Z date_published: 2016-03-01T00:00:00Z date_updated: 2023-09-07T11:55:26Z day: '01' ddc: - '570' degree_awarded: PhD department: - _id: PeJo file: - access_level: closed checksum: 5a010a838faf040f7064f3cfb802f743 content_type: application/pdf creator: dernst date_created: 2019-08-09T12:14:46Z date_updated: 2020-07-14T12:44:48Z file_id: '6782' file_name: Thesis_Mishra_Rajiv (Final).pdf file_size: 2407572 relation: main_file - access_level: open_access checksum: 81b26d9ede92c99f1d8cc6fa1d04cbbb content_type: application/pdf creator: dernst date_created: 2021-02-22T11:48:44Z date_updated: 2021-02-22T11:48:44Z file_id: '9183' file_name: 2016_RajivMishra_Thesis.pdf file_size: 2407572 relation: main_file success: 1 file_date_updated: 2021-02-22T11:48:44Z has_accepted_license: '1' language: - iso: eng month: '03' oa: 1 oa_version: Published Version page: '83' publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '5811' related_material: record: - id: '1432' relation: part_of_dissertation status: public status: public supervisor: - first_name: Peter M full_name: Jonas, Peter M id: 353C1B58-F248-11E8-B48F-1D18A9856A87 last_name: Jonas orcid: 0000-0001-5001-4804 title: Synaptic plasticity rules at CA3-CA3 recurrent synapses in hippocampus type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2016' ... --- _id: '1125' abstract: - lang: eng text: "Natural environments are never constant but subject to spatial and temporal change on\r\nall scales, increasingly so due to human activity. Hence, it is crucial to understand the\r\nimpact of environmental variation on evolutionary processes. In this thesis, I present\r\nthree topics that share the common theme of environmental variation, yet illustrate its\r\neffect from different perspectives.\r\nFirst, I show how a temporally fluctuating environment gives rise to second-order\r\nselection on a modifier for stress-induced mutagenesis. Without fluctuations, when\r\npopulations are adapted to their environment, mutation rates are minimized. I argue\r\nthat a stress-induced mutator mechanism may only be maintained if the population is\r\nrepeatedly subjected to diverse environmental challenges, and I outline implications of\r\nthe presented results to antibiotic treatment strategies.\r\nSecond, I discuss my work on the evolution of dispersal. Besides reproducing\r\nknown results about the effect of heterogeneous habitats on dispersal, it identifies\r\nspatial changes in dispersal type frequencies as a source for selection for increased\r\npropensities to disperse. This concept contains effects of relatedness that are known\r\nto promote dispersal, and I explain how it identifies other forces selecting for dispersal\r\nand puts them on a common scale.\r\nThird, I analyse genetic variances of phenotypic traits under multivariate stabilizing\r\nselection. For the case of constant environments, I generalize known formulae of\r\nequilibrium variances to multiple traits and discuss how the genetic variance of a focal\r\ntrait is influenced by selection on background traits. I conclude by presenting ideas and\r\npreliminary work aiming at including environmental fluctuations in the form of moving\r\ntrait optima into the model." alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Sebastian full_name: Novak, Sebastian id: 461468AE-F248-11E8-B48F-1D18A9856A87 last_name: Novak orcid: 0000-0002-2519-824X citation: ama: Novak S. Evolutionary proccesses in variable emvironments. 2016. apa: Novak, S. (2016). Evolutionary proccesses in variable emvironments. Institute of Science and Technology Austria. chicago: Novak, Sebastian. “Evolutionary Proccesses in Variable Emvironments.” Institute of Science and Technology Austria, 2016. ieee: S. Novak, “Evolutionary proccesses in variable emvironments,” Institute of Science and Technology Austria, 2016. ista: Novak S. 2016. Evolutionary proccesses in variable emvironments. Institute of Science and Technology Austria. mla: Novak, Sebastian. Evolutionary Proccesses in Variable Emvironments. Institute of Science and Technology Austria, 2016. short: S. Novak, Evolutionary Proccesses in Variable Emvironments, Institute of Science and Technology Austria, 2016. date_created: 2018-12-11T11:50:17Z date_published: 2016-07-01T00:00:00Z date_updated: 2023-09-07T11:55:53Z day: '01' ddc: - '576' degree_awarded: PhD department: - _id: NiBa file: - access_level: closed checksum: 81dcc838dfcf7aa0b1a27ecf4fe2da4e content_type: application/pdf creator: dernst date_created: 2019-08-13T09:01:00Z date_updated: 2019-08-13T09:01:00Z file_id: '6811' file_name: Novak_thesis.pdf file_size: 3564901 relation: main_file - access_level: open_access checksum: 30808d2f7ca920e09f63a95cdc49bffd content_type: application/pdf creator: dernst date_created: 2021-02-22T13:42:47Z date_updated: 2021-02-22T13:42:47Z file_id: '9186' file_name: 2016_Novak_Thesis.pdf file_size: 2814384 relation: main_file success: 1 file_date_updated: 2021-02-22T13:42:47Z has_accepted_license: '1' language: - iso: eng month: '07' oa: 1 oa_version: Published Version page: '124' publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '6235' related_material: record: - id: '2023' relation: part_of_dissertation status: public status: public supervisor: - first_name: Nicholas H full_name: Barton, Nicholas H id: 4880FE40-F248-11E8-B48F-1D18A9856A87 last_name: Barton orcid: 0000-0002-8548-5240 title: Evolutionary proccesses in variable emvironments type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2016' ... --- _id: '1130' abstract: - lang: eng text: "In this thesis we present a computer-aided programming approach to concurrency. Our approach helps the programmer by automatically fixing concurrency-related bugs, i.e. bugs that occur when the program is executed using an aggressive preemptive scheduler, but not when using a non-preemptive (cooperative) scheduler. Bugs are program behaviours that are incorrect w.r.t. a specification. We consider both user-provided explicit specifications in the form of assertion\r\nstatements in the code as well as an implicit specification. The implicit specification is inferred from the non-preemptive behaviour. Let us consider sequences of calls that the program makes to an external interface. The implicit specification requires that any such sequence produced under a preemptive scheduler should be included in the set of sequences produced under a non-preemptive scheduler. We consider several semantics-preserving fixes that go beyond atomic sections typically explored in the synchronisation synthesis literature. Our synthesis is able to place locks, barriers and wait-signal statements and last, but not least reorder independent statements. The latter may be useful if a thread is released to early, e.g., before some initialisation is completed. We guarantee that our synthesis does not introduce deadlocks and that the synchronisation inserted is optimal w.r.t. a given objective function. We dub our solution trace-based synchronisation synthesis and it is loosely based on counterexample-guided inductive synthesis (CEGIS). The synthesis works by discovering a trace that is incorrect w.r.t. the specification and identifying ordering constraints crucial to trigger the specification violation. Synchronisation may be placed immediately (greedy approach) or delayed until all incorrect traces are found (non-greedy approach). For the non-greedy approach we construct a set of global constraints over synchronisation placements. Each model of the global constraints set corresponds to a correctness-ensuring synchronisation placement. The placement that is optimal w.r.t. the given objective function is chosen as the synchronisation solution. We evaluate our approach on a number of realistic (albeit simplified) Linux device-driver\r\nbenchmarks. The benchmarks are versions of the drivers with known concurrency-related bugs. For the experiments with an explicit specification we added assertions that would detect the bugs in the experiments. Device drivers lend themselves to implicit specification, where the device and the operating system are the external interfaces. Our experiments demonstrate that our synthesis method is precise and efficient. We implemented objective functions for coarse-grained and fine-grained locking and observed that different synchronisation placements are produced for our experiments, favouring e.g. a minimal number of synchronisation operations or maximum concurrency." alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Thorsten full_name: Tarrach, Thorsten id: 3D6E8F2C-F248-11E8-B48F-1D18A9856A87 last_name: Tarrach orcid: 0000-0003-4409-8487 citation: ama: Tarrach T. Automatic synthesis of synchronisation primitives for concurrent programs. 2016. doi:10.15479/at:ista:1130 apa: Tarrach, T. (2016). Automatic synthesis of synchronisation primitives for concurrent programs. Institute of Science and Technology Austria. https://doi.org/10.15479/at:ista:1130 chicago: Tarrach, Thorsten. “Automatic Synthesis of Synchronisation Primitives for Concurrent Programs.” Institute of Science and Technology Austria, 2016. https://doi.org/10.15479/at:ista:1130. ieee: T. Tarrach, “Automatic synthesis of synchronisation primitives for concurrent programs,” Institute of Science and Technology Austria, 2016. ista: Tarrach T. 2016. Automatic synthesis of synchronisation primitives for concurrent programs. Institute of Science and Technology Austria. mla: Tarrach, Thorsten. Automatic Synthesis of Synchronisation Primitives for Concurrent Programs. Institute of Science and Technology Austria, 2016, doi:10.15479/at:ista:1130. short: T. Tarrach, Automatic Synthesis of Synchronisation Primitives for Concurrent Programs, Institute of Science and Technology Austria, 2016. date_created: 2018-12-11T11:50:19Z date_published: 2016-07-07T00:00:00Z date_updated: 2023-09-07T11:57:01Z day: '07' ddc: - '000' degree_awarded: PhD department: - _id: ToHe - _id: GradSch doi: 10.15479/at:ista:1130 ec_funded: 1 file: - access_level: open_access checksum: 319a506831650327e85376db41fc1094 content_type: application/pdf creator: dernst date_created: 2021-02-22T11:39:32Z date_updated: 2021-02-22T11:39:32Z file_id: '9179' file_name: 2016_Tarrach_Thesis.pdf file_size: 1523935 relation: main_file success: 1 - access_level: closed checksum: 39efcd789f0ad859ff15652cb7afc412 content_type: application/pdf creator: cchlebak date_created: 2021-11-16T14:14:38Z date_updated: 2021-11-17T13:46:55Z file_id: '10296' file_name: 2016_Tarrach_Thesispdfa.pdf file_size: 1306068 relation: main_file file_date_updated: 2021-11-17T13:46:55Z has_accepted_license: '1' language: - iso: eng main_file_link: - open_access: '1' url: http://thorstent.github.io/theses/phd_thorsten_tarrach.pdf month: '07' oa: 1 oa_version: Published Version page: '151' project: - _id: 25EE3708-B435-11E9-9278-68D0E5697425 call_identifier: FP7 grant_number: '267989' name: Quantitative Reactive Modeling - _id: 25832EC2-B435-11E9-9278-68D0E5697425 call_identifier: FWF grant_number: S 11407_N23 name: Rigorous Systems Engineering - _id: 25F42A32-B435-11E9-9278-68D0E5697425 call_identifier: FWF grant_number: Z211 name: The Wittgenstein Prize publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '6230' related_material: record: - id: '1729' relation: part_of_dissertation status: public - id: '2218' relation: part_of_dissertation status: public - id: '2445' relation: part_of_dissertation status: public status: public supervisor: - first_name: Thomas A full_name: Henzinger, Thomas A id: 40876CD8-F248-11E8-B48F-1D18A9856A87 last_name: Henzinger orcid: 0000−0002−2985−7724 title: Automatic synthesis of synchronisation primitives for concurrent programs type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2016' ... --- _id: '1122' abstract: - lang: eng text: "Computer graphics is an extremely exciting field for two reasons. On the one hand,\r\nthere is a healthy injection of pragmatism coming from the visual effects industry\r\nthat want robust algorithms that work so they can produce results at an increasingly\r\nfrantic pace. On the other hand, they must always try to push the envelope and\r\nachieve the impossible to wow their audiences in the next blockbuster, which means\r\nthat the industry has not succumb to conservatism, and there is plenty of room to\r\ntry out new and crazy ideas if there is a chance that it will pan into something\r\nuseful.\r\nWater simulation has been in visual effects for decades, however it still remains\r\nextremely challenging because of its high computational cost and difficult artdirectability.\r\nThe work in this thesis tries to address some of these difficulties.\r\nSpecifically, we make the following three novel contributions to the state-of-the-art\r\nin water simulation for visual effects.\r\nFirst, we develop the first algorithm that can convert any sequence of closed\r\nsurfaces in time into a moving triangle mesh. State-of-the-art methods at the time\r\ncould only handle surfaces with fixed connectivity, but we are the first to be able to\r\nhandle surfaces that merge and split apart. This is important for water simulation\r\npractitioners, because it allows them to convert splashy water surfaces extracted\r\nfrom particles or simulated using grid-based level sets into triangle meshes that can\r\nbe either textured and enhanced with extra surface dynamics as a post-process.\r\nWe also apply our algorithm to other phenomena that merge and split apart, such\r\nas morphs and noisy reconstructions of human performances.\r\nSecond, we formulate a surface-based energy that measures the deviation of a\r\nwater surface froma physically valid state. Such discrepancies arise when there is a\r\nmismatch in the degrees of freedom between the water surface and the underlying\r\nphysics solver. This commonly happens when practitioners use a moving triangle\r\nmesh with a grid-based physics solver, or when high-resolution grid-based surfaces\r\nare combined with low-resolution physics. Following the direction of steepest\r\ndescent on our surface-based energy, we can either smooth these artifacts or turn\r\nthem into high-resolution waves by interpreting the energy as a physical potential.\r\nThird, we extend state-of-the-art techniques in non-reflecting boundaries to handle spatially and time-varying background flows. This allows a novel new\r\nworkflow where practitioners can re-simulate part of an existing simulation, such\r\nas removing a solid obstacle, adding a new splash or locally changing the resolution.\r\nSuch changes can easily lead to new waves in the re-simulated region that would\r\nreflect off of the new simulation boundary, effectively ruining the illusion of a\r\nseamless simulation boundary between the existing and new simulations. Our\r\nnon-reflecting boundaries makes sure that such waves are absorbed." acknowledgement: "First and foremost I would like to thank Chris. I have been incredibly lucky to have\r\nyou as my advisor. Your integrity and aspiration to do the right thing in all walks of\r\nlife is something I admire and aspire to. I also really appreciate the fact that when\r\nworking with you it felt like we were equals. I think we had a very synergetic work\r\nrelationship: I learned immensely from you, but I dare say that you learned a few\r\nthings from me as well. ;)\r\nNext, I would like to thank my amazing committee. Hao, it was a fantastic\r\nexperience working with you. You showed me how to persevere and keep morale\r\nhigh when things were looking the most bleak before the deadline. You are an\r\nincredible motivator and super fun to be around! Vladimir, thanks for the shared\r\nlunches and the poker games. Sorry for not bringing them back when I got busy.\r\nAlso, sorry for embarrassing you by asking about your guitar playing that one\r\ntime. You really are quite awesome! Nils, one of the friendliest and most humble\r\npeople you will meet and a top notch researcher to boot! Thank you for joining\r\nmy committee late!\r\nI would also like to acknowledge the Visual Computing group at IST Austria\r\nfrom whom I have learned so much. The excellent discussions we had in reading\r\ngroups and research meetings really helped me become a better researcher!\r\nNext, I would like to thank all the amazing people that I met during my PhD\r\nstudies, both at IST Austria, in Vienna and elsewhere. " alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Morten full_name: Bojsen-Hansen, Morten id: 439F0C8C-F248-11E8-B48F-1D18A9856A87 last_name: Bojsen-Hansen orcid: 0000-0002-4417-3224 citation: ama: Bojsen-Hansen M. Tracking, correcting and absorbing water surface waves. 2016. doi:10.15479/AT:ISTA:th_640 apa: Bojsen-Hansen, M. (2016). Tracking, correcting and absorbing water surface waves. Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:th_640 chicago: Bojsen-Hansen, Morten. “Tracking, Correcting and Absorbing Water Surface Waves.” Institute of Science and Technology Austria, 2016. https://doi.org/10.15479/AT:ISTA:th_640. ieee: M. Bojsen-Hansen, “Tracking, correcting and absorbing water surface waves,” Institute of Science and Technology Austria, 2016. ista: Bojsen-Hansen M. 2016. Tracking, correcting and absorbing water surface waves. Institute of Science and Technology Austria. mla: Bojsen-Hansen, Morten. Tracking, Correcting and Absorbing Water Surface Waves. Institute of Science and Technology Austria, 2016, doi:10.15479/AT:ISTA:th_640. short: M. Bojsen-Hansen, Tracking, Correcting and Absorbing Water Surface Waves, Institute of Science and Technology Austria, 2016. date_created: 2018-12-11T11:50:16Z date_published: 2016-07-15T00:00:00Z date_updated: 2024-02-21T13:50:48Z day: '15' ddc: - '004' - '005' - '006' - '532' - '621' degree_awarded: PhD department: - _id: ChWo doi: 10.15479/AT:ISTA:th_640 file: - access_level: open_access content_type: application/pdf creator: system date_created: 2018-12-12T10:13:02Z date_updated: 2018-12-12T10:13:02Z file_id: '4982' file_name: IST-2016-640-v1+1_2016_Bojsen-Hansen_TCaAWSW.pdf file_size: 13869345 relation: main_file file_date_updated: 2018-12-12T10:13:02Z has_accepted_license: '1' language: - iso: eng month: '07' oa: 1 oa_version: Published Version page: '114' publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '6238' related_material: record: - id: '5558' relation: other status: public status: public supervisor: - first_name: Christopher J full_name: Wojtan, Christopher J id: 3C61F1D2-F248-11E8-B48F-1D18A9856A87 last_name: Wojtan orcid: 0000-0001-6646-5546 title: Tracking, correcting and absorbing water surface waves tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2016' ... --- _id: '1398' abstract: - lang: eng text: Hybrid zones represent evolutionary laboratories, where recombination brings together alleles in combinations which have not previously been tested by selection. This provides an excellent opportunity to test the effect of molecular variation on fitness, and how this variation is able to spread through populations in a natural context. The snapdragon Antirrhinum majus is polymorphic in the wild for two loci controlling the distribution of yellow and magenta floral pigments. Where the yellow A. m. striatum and the magenta A. m. pseudomajus meet along a valley in the Spanish Pyrenees they form a stable hybrid zone Alleles at these loci recombine to give striking transgressive variation for flower colour. The sharp transition in phenotype over ~1km implies strong selection maintaining the hybrid zone. An indirect assay of pollinator visitation in the field found that pollinators forage in a positive-frequency dependent manner on Antirrhinum, matching previous data on fruit set. Experimental arrays and paternity analysis of wild-pollinated seeds demonstrated assortative mating for pigmentation alleles, and that pollinator behaviour alone is sufficient to explain this pattern. Selection by pollinators should be sufficiently strong to maintain the hybrid zone, although other mechanisms may be at work. At a broader scale I examined evolutionary transitions between yellow and anthocyanin pigmentation in the tribe Antirrhinae, and found that selection has acted strate that pollinators are a major determinant of reproductive success and mating patterns in wild Antirrhinum. acknowledgement: "I am indebted to many people for their support during my PhD, but I particularly wish to thank Nick Barton for his guidance and intuition, and for encouraging me to take the time to look beyond the immediate topic of my PhD to understand the broader context. I am also especially grateful to David Field his bottomless patience, invaluable advice on experimental design, analysis and scientific writing, and for tireless work on the population surveys and genomic work without most of my thesis could not have happened. \r\n\r\nIt has been a pleasure to work with the combined strengths of the groups at The John Innes Centre, University of Toulouse and IST Austria. Thanks to Enrico Coen and his group for hosting me in Norwich in 2011 and especially for setting up the tag experiment. \r\n\r\nI thank David Field, Desmond Bradley and Maria Clara Melo-Hurtado for organising field collections, as well as Monique Burrus and Christophe Andalo and a large number of volunteers for their e ff orts helping with the field work. Furthermore I thank Coline Jaworski for providing seeds and for her input into the design of the experimental arrays, and Matthew Couchman for maintaining the database of. \r\n\r\nIn addition to those mentioned above, I am grateful to Melinda Pickup, Spencer Barrett, and four anonymous reviewers for their insightful comments on sections of this manuscript. I also thank Jana Porsche for her e ff orts in tracking down the more obscure references for chapter 5, and Jon Bollback for his advice about the analysis. \r\n\r\nI am indebted to Jon Ågren for his patience whilst I finished this thesis, and to Sylvia Cremer and Magnus Nordborg for taking the time to read and evaluate the thesis given a shorter deadline than was fair. \r\n\r\nA very positive aspect of my PhD has been the supportive atmosphere of IST. In particular, I have come to appreciate the enormous support from our group assistants Nicole Hotzy, Julia Asimakis, Christine Ostermann and Jerneja Beslagic. I also thank Christian Chaloupka and Stefan Hipfinger for their enthusiasm and readiness to help where possible in setting up our greenhouse and experiments. " alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Thomas full_name: Ellis, Thomas id: 3153D6D4-F248-11E8-B48F-1D18A9856A87 last_name: Ellis orcid: 0000-0002-8511-0254 citation: ama: Ellis T. The role of pollinator-mediated selection in the maintenance of a flower color polymorphism in an Antirrhinum majus hybrid zone. 2016. doi:10.15479/AT:ISTA:TH_526 apa: Ellis, T. (2016). The role of pollinator-mediated selection in the maintenance of a flower color polymorphism in an Antirrhinum majus hybrid zone. Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:TH_526 chicago: Ellis, Thomas. “The Role of Pollinator-Mediated Selection in the Maintenance of a Flower Color Polymorphism in an Antirrhinum Majus Hybrid Zone.” Institute of Science and Technology Austria, 2016. https://doi.org/10.15479/AT:ISTA:TH_526 . ieee: T. Ellis, “The role of pollinator-mediated selection in the maintenance of a flower color polymorphism in an Antirrhinum majus hybrid zone,” Institute of Science and Technology Austria, 2016. ista: Ellis T. 2016. The role of pollinator-mediated selection in the maintenance of a flower color polymorphism in an Antirrhinum majus hybrid zone. Institute of Science and Technology Austria. mla: Ellis, Thomas. The Role of Pollinator-Mediated Selection in the Maintenance of a Flower Color Polymorphism in an Antirrhinum Majus Hybrid Zone. Institute of Science and Technology Austria, 2016, doi:10.15479/AT:ISTA:TH_526 . short: T. Ellis, The Role of Pollinator-Mediated Selection in the Maintenance of a Flower Color Polymorphism in an Antirrhinum Majus Hybrid Zone, Institute of Science and Technology Austria, 2016. date_created: 2018-12-11T11:51:47Z date_published: 2016-02-18T00:00:00Z date_updated: 2024-02-21T13:51:39Z day: '18' ddc: - '576' degree_awarded: PhD department: - _id: NiBa doi: '10.15479/AT:ISTA:TH_526 ' file: - access_level: open_access checksum: a89b17ff27cf92c9a15f6b3d46bd7e53 content_type: application/pdf creator: system date_created: 2018-12-12T10:14:51Z date_updated: 2020-07-14T12:44:48Z file_id: '5106' file_name: IST-2016-526-v1+1_Ellis_signed_thesis.pdf file_size: 11928241 relation: main_file file_date_updated: 2020-07-14T12:44:48Z has_accepted_license: '1' language: - iso: eng month: '02' oa: 1 oa_version: Published Version page: '130' publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '5809' pubrep_id: '526' related_material: record: - id: '5553' relation: popular_science status: public - id: '5551' relation: popular_science status: public - id: '5552' relation: popular_science status: public status: public supervisor: - first_name: Nicholas H full_name: Barton, Nicholas H id: 4880FE40-F248-11E8-B48F-1D18A9856A87 last_name: Barton orcid: 0000-0002-8548-5240 title: The role of pollinator-mediated selection in the maintenance of a flower color polymorphism in an Antirrhinum majus hybrid zone type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2016' ... --- _id: '1131' abstract: - lang: eng text: "Evolution of gene regulation is important for phenotypic evolution and diversity. Sequence-specific binding of regulatory proteins is one of the key regulatory mechanisms determining gene expression. Although there has been intense interest in evolution of regulatory binding sites in the last decades, a theoretical understanding is far from being complete. In this thesis, I aim at a better understanding of the evolution of transcriptional regulatory binding sequences by using biophysical and population genetic models.\r\nIn the first part of the thesis, I discuss how to formulate the evolutionary dynamics of binding se- quences in a single isolated binding site and in promoter/enhancer regions. I develop a theoretical framework bridging between a thermodynamical model for transcription and a mutation-selection-drift model for monomorphic populations. I mainly address the typical evolutionary rates, and how they de- pend on biophysical parameters (e.g. binding length and specificity) and population genetic parameters (e.g. population size and selection strength).\r\nIn the second part of the thesis, I analyse empirical data for a better evolutionary and biophysical understanding of sequence-specific binding of bacterial RNA polymerase. First, I infer selection on regulatory and non-regulatory binding sites of RNA polymerase in the E. coli K12 genome. Second, I infer the chemical potential of RNA polymerase, an important but unknown physical parameter defining the threshold energy for strong binding. Furthermore, I try to understand the relation between the lac promoter sequence diversity and the LacZ activity variation among 20 bacterial isolates by constructing a simple but biophysically motivated gene expression model. Lastly, I lay out a statistical framework to predict adaptive point mutations in de novo promoter evolution in a selection experiment." acknowledgement: This PhD thesis may not have been completed without the help and care I received from some peo- ple during my PhD life. I am especially grateful to Tiago Paixao, Gasper Tkacik, Nick Barton, not only for their scientific advices but also for their patience and support. I thank Calin Guet and Jonathan Bollback for allowing me to “play around” in their labs and get some experience on experimental evolution. I thank Magdalena Steinrueck and Fabienne Jesse for collaborating and sharing their experimental data with me. I thank Johannes Jaeger for reviewing my thesis. I thank all members of Barton group (aka bartonians) for their feedback, and all workers of IST Austria for making the best working conditions. Lastly, I thank two special women, Nejla Sag ̆lam and Setenay Dog ̆an, for their continuous support and encouragement. I truly had a great chance of having right people around me. alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Murat full_name: Tugrul, Murat id: 37C323C6-F248-11E8-B48F-1D18A9856A87 last_name: Tugrul orcid: 0000-0002-8523-0758 citation: ama: Tugrul M. Evolution of transcriptional regulatory sequences. 2016. apa: Tugrul, M. (2016). Evolution of transcriptional regulatory sequences. Institute of Science and Technology Austria. chicago: Tugrul, Murat. “Evolution of Transcriptional Regulatory Sequences.” Institute of Science and Technology Austria, 2016. ieee: M. Tugrul, “Evolution of transcriptional regulatory sequences,” Institute of Science and Technology Austria, 2016. ista: Tugrul M. 2016. Evolution of transcriptional regulatory sequences. Institute of Science and Technology Austria. mla: Tugrul, Murat. Evolution of Transcriptional Regulatory Sequences. Institute of Science and Technology Austria, 2016. short: M. Tugrul, Evolution of Transcriptional Regulatory Sequences, Institute of Science and Technology Austria, 2016. date_created: 2018-12-11T11:50:19Z date_published: 2016-07-01T00:00:00Z date_updated: 2024-02-21T13:50:34Z day: '01' ddc: - '576' degree_awarded: PhD department: - _id: NiBa file: - access_level: closed checksum: 66cb61a59943e4fb7447c6a86be5ef51 content_type: application/pdf creator: dernst date_created: 2019-08-13T08:53:52Z date_updated: 2019-08-13T08:53:52Z file_id: '6810' file_name: Tugrul_thesis_w_signature_page.pdf file_size: 3695257 relation: main_file - access_level: open_access checksum: 293e388d70563760f6b24c3e66283dda content_type: application/pdf creator: dernst date_created: 2021-02-22T11:45:20Z date_updated: 2021-02-22T11:45:20Z file_id: '9182' file_name: 2016_Tugrul_Thesis.pdf file_size: 3880811 relation: main_file success: 1 file_date_updated: 2021-02-22T11:45:20Z has_accepted_license: '1' language: - iso: eng month: '07' oa: 1 oa_version: Published Version page: '89' publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '6229' related_material: record: - id: '1666' relation: part_of_dissertation status: public - id: '5554' relation: research_data status: public status: public supervisor: - first_name: Nicholas H full_name: Barton, Nicholas H id: 4880FE40-F248-11E8-B48F-1D18A9856A87 last_name: Barton orcid: 0000-0002-8548-5240 title: Evolution of transcriptional regulatory sequences type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2016' ... --- _id: '1401' abstract: - lang: eng text: 'The human ability to recognize objects in complex scenes has driven research in the computer vision field over couple of decades. This thesis focuses on the object recognition task in images. That is, given the image, we want the computer system to be able to predict the class of the object that appears in the image. A recent successful attempt to bridge semantic understanding of the image perceived by humans and by computers uses attribute-based models. Attributes are semantic properties of the objects shared across different categories, which humans and computers can decide on. To explore the attribute-based models we take a statistical machine learning approach, and address two key learning challenges in view of object recognition task: learning augmented attributes as mid-level discriminative feature representation, and learning with attributes as privileged information. Our main contributions are parametric and non-parametric models and algorithms to solve these frameworks. In the parametric approach, we explore an autoencoder model combined with the large margin nearest neighbor principle for mid-level feature learning, and linear support vector machines for learning with privileged information. In the non-parametric approach, we propose a supervised Indian Buffet Process for automatic augmentation of semantic attributes, and explore the Gaussian Processes classification framework for learning with privileged information. A thorough experimental analysis shows the effectiveness of the proposed models in both parametric and non-parametric views.' acknowledgement: "I would like to thank my supervisor, Christoph Lampert, for guidance throughout my studies and for patience in transforming me into a scientist, and my thesis committee, Chris Wojtan and Horst Bischof, for their help and advice. \r\n\r\nI would like to thank Elisabeth Hacker who perfectly assisted all my administrative needs and was always nice and friendly to me, and the campus team for making the IST Austria campus my second home. \r\nI was honored to collaborate with brilliant researchers and to learn from their experience. Undoubtedly, I learned most of all from Novi Quadrianto: brainstorming our projects and getting exciting results was the most enjoyable part of my work – thank you! I am also grateful to David Knowles, Zoubin Ghahramani, Daniel Hernández-Lobato, Kristian Kersting and Anastasia Pentina for the fantastic projects we worked on together, and to Kristen Grauman and Adriana Kovashka for the exceptional experience working with user studies. I would like to thank my colleagues at IST Austria and my office mates who shared their happy moods, scientific breakthroughs and thought-provoking conversations with me: Chao, Filip, Rustem, Asya, Sameh, Alex, Vlad, Mayu, Neel, Csaba, Thomas, Vladimir, Cristina, Alex Z., Avro, Amelie and Emilie, Andreas H. and Andreas E., Chris, Lena, Michael, Ali and Ipek, Vera, Igor, Katia. Special thanks to Morten for the countless games of table soccer we played together and the tournaments we teamed up for: we will definitely win next time:) A very warm hug to Asya for always being so inspiring and supportive to me, and for helping me to increase the proportion of female computer scientists in our group. " alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Viktoriia full_name: Sharmanska, Viktoriia id: 2EA6D09E-F248-11E8-B48F-1D18A9856A87 last_name: Sharmanska orcid: 0000-0003-0192-9308 citation: ama: 'Sharmanska V. Learning with attributes for object recognition: Parametric and non-parametrics views. 2015. doi:10.15479/at:ista:1401' apa: 'Sharmanska, V. (2015). Learning with attributes for object recognition: Parametric and non-parametrics views. Institute of Science and Technology Austria. https://doi.org/10.15479/at:ista:1401' chicago: 'Sharmanska, Viktoriia. “Learning with Attributes for Object Recognition: Parametric and Non-Parametrics Views.” Institute of Science and Technology Austria, 2015. https://doi.org/10.15479/at:ista:1401.' ieee: 'V. Sharmanska, “Learning with attributes for object recognition: Parametric and non-parametrics views,” Institute of Science and Technology Austria, 2015.' ista: 'Sharmanska V. 2015. Learning with attributes for object recognition: Parametric and non-parametrics views. Institute of Science and Technology Austria.' mla: 'Sharmanska, Viktoriia. Learning with Attributes for Object Recognition: Parametric and Non-Parametrics Views. Institute of Science and Technology Austria, 2015, doi:10.15479/at:ista:1401.' short: 'V. Sharmanska, Learning with Attributes for Object Recognition: Parametric and Non-Parametrics Views, Institute of Science and Technology Austria, 2015.' date_created: 2018-12-11T11:51:48Z date_published: 2015-04-01T00:00:00Z date_updated: 2023-09-07T11:40:11Z day: '01' ddc: - '000' degree_awarded: PhD department: - _id: ChLa - _id: GradSch doi: 10.15479/at:ista:1401 file: - access_level: open_access checksum: 3605b402bb6934e09ae4cf672c84baf7 content_type: application/pdf creator: dernst date_created: 2021-02-22T11:33:17Z date_updated: 2021-02-22T11:33:17Z file_id: '9177' file_name: 2015_Thesis_Sharmanska.pdf file_size: 7964342 relation: main_file success: 1 - access_level: closed checksum: e37593b3ee75bf3180629df2d6ca8f4e content_type: application/pdf creator: cchlebak date_created: 2021-11-16T14:40:45Z date_updated: 2021-11-17T13:47:24Z file_id: '10297' file_name: 2015_Thesis_Sharmanska_pdfa.pdf file_size: 7372241 relation: main_file file_date_updated: 2021-11-17T13:47:24Z has_accepted_license: '1' language: - iso: eng main_file_link: - url: http://users.sussex.ac.uk/~nq28/viktoriia/Thesis_Sharmanska.pdf month: '04' oa: 1 oa_version: Published Version page: '144' publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '5806' status: public supervisor: - first_name: Christoph full_name: Lampert, Christoph id: 40C20FD2-F248-11E8-B48F-1D18A9856A87 last_name: Lampert orcid: 0000-0001-8622-7887 title: 'Learning with attributes for object recognition: Parametric and non-parametrics views' type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2015' ... --- _id: '1400' abstract: - lang: eng text: Cancer results from an uncontrolled growth of abnormal cells. Sequentially accumulated genetic and epigenetic alterations decrease cell death and increase cell replication. We used mathematical models to quantify the effect of driver gene mutations. The recently developed targeted therapies can lead to dramatic regressions. However, in solid cancers, clinical responses are often short-lived because resistant cancer cells evolve. We estimated that approximately 50 different mutations can confer resistance to a typical targeted therapeutic agent. We find that resistant cells are likely to be present in expanded subclones before the start of the treatment. The dominant strategy to prevent the evolution of resistance is combination therapy. Our analytical results suggest that in most patients, dual therapy, but not monotherapy, can result in long-term disease control. However, long-term control can only occur if there are no possible mutations in the genome that can cause cross-resistance to both drugs. Furthermore, we showed that simultaneous therapy with two drugs is much more likely to result in long-term disease control than sequential therapy with the same drugs. To improve our understanding of the underlying subclonal evolution we reconstruct the evolutionary history of a patient's cancer from next-generation sequencing data of spatially-distinct DNA samples. Using a quantitative measure of genetic relatedness, we found that pancreatic cancers and their metastases demonstrated a higher level of relatedness than that expected for any two cells randomly taken from a normal tissue. This minimal amount of genetic divergence among advanced lesions indicates that genetic heterogeneity, when quantitatively defined, is not a fundamental feature of the natural history of untreated pancreatic cancers. Our newly developed, phylogenomic tool Treeomics finds evidence for seeding patterns of metastases and can directly be used to discover rules governing the evolution of solid malignancies to transform cancer into a more predictable disease. alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Johannes full_name: Reiter, Johannes id: 4A918E98-F248-11E8-B48F-1D18A9856A87 last_name: Reiter orcid: 0000-0002-0170-7353 citation: ama: Reiter J. The subclonal evolution of cancer. 2015. apa: Reiter, J. (2015). The subclonal evolution of cancer. Institute of Science and Technology Austria. chicago: Reiter, Johannes. “The Subclonal Evolution of Cancer.” Institute of Science and Technology Austria, 2015. ieee: J. Reiter, “The subclonal evolution of cancer,” Institute of Science and Technology Austria, 2015. ista: Reiter J. 2015. The subclonal evolution of cancer. Institute of Science and Technology Austria. mla: Reiter, Johannes. The Subclonal Evolution of Cancer. Institute of Science and Technology Austria, 2015. short: J. Reiter, The Subclonal Evolution of Cancer, Institute of Science and Technology Austria, 2015. date_created: 2018-12-11T11:51:48Z date_published: 2015-04-01T00:00:00Z date_updated: 2023-09-07T11:40:44Z day: '01' degree_awarded: PhD department: - _id: KrCh language: - iso: eng month: '04' oa_version: None page: '183' publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '5807' related_material: record: - id: '1709' relation: part_of_dissertation status: public - id: '2000' relation: part_of_dissertation status: public - id: '2247' relation: part_of_dissertation status: public - id: '2816' relation: part_of_dissertation status: public - id: '2858' relation: part_of_dissertation status: public - id: '3157' relation: part_of_dissertation status: public - id: '3260' relation: part_of_dissertation status: public status: public supervisor: - first_name: Krishnendu full_name: Chatterjee, Krishnendu id: 2E5DCA20-F248-11E8-B48F-1D18A9856A87 last_name: Chatterjee orcid: 0000-0002-4561-241X title: The subclonal evolution of cancer type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2015' ... --- _id: '1399' abstract: - lang: eng text: This thesis is concerned with the computation and approximation of intrinsic volumes. Given a smooth body M and a certain digital approximation of it, we develop algorithms to approximate various intrinsic volumes of M using only measurements taken from its digital approximations. The crucial idea behind our novel algorithms is to link the recent theory of persistent homology to the theory of intrinsic volumes via the Crofton formula from integral geometry and, in particular, via Euler characteristic computations. Our main contributions are a multigrid convergent digital algorithm to compute the first intrinsic volume of a solid body in R^n as well as an appropriate integration pipeline to approximate integral-geometric integrals defined over the Grassmannian manifold. alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Florian full_name: Pausinger, Florian id: 2A77D7A2-F248-11E8-B48F-1D18A9856A87 last_name: Pausinger orcid: 0000-0002-8379-3768 citation: ama: Pausinger F. On the approximation of intrinsic volumes. 2015. apa: Pausinger, F. (2015). On the approximation of intrinsic volumes. Institute of Science and Technology Austria. chicago: Pausinger, Florian. “On the Approximation of Intrinsic Volumes.” Institute of Science and Technology Austria, 2015. ieee: F. Pausinger, “On the approximation of intrinsic volumes,” Institute of Science and Technology Austria, 2015. ista: Pausinger F. 2015. On the approximation of intrinsic volumes. Institute of Science and Technology Austria. mla: Pausinger, Florian. On the Approximation of Intrinsic Volumes. Institute of Science and Technology Austria, 2015. short: F. Pausinger, On the Approximation of Intrinsic Volumes, Institute of Science and Technology Austria, 2015. date_created: 2018-12-11T11:51:48Z date_published: 2015-06-01T00:00:00Z date_updated: 2023-09-07T11:41:25Z day: '01' degree_awarded: PhD department: - _id: HeEd language: - iso: eng month: '06' oa_version: None page: '144' publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '5808' related_material: record: - id: '1662' relation: part_of_dissertation status: public - id: '1792' relation: part_of_dissertation status: public - id: '2255' relation: part_of_dissertation status: public status: public supervisor: - first_name: Herbert full_name: Edelsbrunner, Herbert id: 3FB178DA-F248-11E8-B48F-1D18A9856A87 last_name: Edelsbrunner orcid: 0000-0002-9823-6833 title: On the approximation of intrinsic volumes type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2015' ... --- _id: '1404' abstract: - lang: eng text: "The co-evolution of hosts and pathogens is characterized by continuous adaptations of both parties. Pathogens of social insects need to adapt towards disease defences at two levels: 1) individual immunity of each colony member consisting of behavioural defence strategies as well as humoral and cellular immune responses and 2) social immunity that is collectively performed by all group members comprising behavioural, physiological and organisational defence strategies.\r\n\r\nTo disentangle the selection pressure on pathogens by the collective versus individual level of disease defence in social insects, we performed an evolution experiment using the Argentine Ant, Linepithema humile, as a host and a mixture of the general insect pathogenic fungus Metarhizium spp. (6 strains) as a pathogen. We allowed pathogen evolution over 10 serial host passages to two different evolution host treatments: (1) only individual host immunity in a single host treatment, and (2) simultaneously acting individual and social immunity in a social host treatment, in which an exposed ant was accompanied by two untreated nestmates.\r\n\r\nBefore starting the pathogen evolution experiment, the 6 Metarhizium spp. strains were characterised concerning conidiospore size killing rates in singly and socially reared ants, their competitiveness under coinfecting conditions and their influence on ant behaviour. We analysed how the ancestral atrain mixture changed in conidiospere size, killing rate and strain composition dependent on host treatment (single or social hosts) during 10 passages and found that killing rate and conidiospere size of the pathogen increased under both evolution regimes, but different depending on host treatment.\r\n\r\nTesting the evolved strain mixtures that evolved under either the single or social host treatment under both single and social current rearing conditions in a full factorial design experiment revealed that the additional collective defences in insect societies add new selection pressure for their coevolving pathogens that compromise their ability to adapt to its host at the group level. To our knowledge, this is the first study directly measuring the influence of social immunity on pathogen evolution." acknowledgement: This work was funded by the DFG and the ERC. alternative_title: - IST Austria Thesis author: - first_name: Miriam full_name: Stock, Miriam id: 42462816-F248-11E8-B48F-1D18A9856A87 last_name: Stock citation: ama: Stock M. Evolution of a fungal pathogen towards individual versus social immunity in ants. 2014. apa: Stock, M. (2014). Evolution of a fungal pathogen towards individual versus social immunity in ants. IST Austria. chicago: Stock, Miriam. “Evolution of a Fungal Pathogen towards Individual versus Social Immunity in Ants.” IST Austria, 2014. ieee: M. Stock, “Evolution of a fungal pathogen towards individual versus social immunity in ants,” IST Austria, 2014. ista: Stock M. 2014. Evolution of a fungal pathogen towards individual versus social immunity in ants. IST Austria. mla: Stock, Miriam. Evolution of a Fungal Pathogen towards Individual versus Social Immunity in Ants. IST Austria, 2014. short: M. Stock, Evolution of a Fungal Pathogen towards Individual versus Social Immunity in Ants, IST Austria, 2014. date_created: 2018-12-11T11:51:49Z date_published: 2014-04-01T00:00:00Z date_updated: 2021-01-12T06:50:30Z day: '01' department: - _id: SyCr language: - iso: eng month: '04' oa_version: None page: '101' publication_status: published publisher: IST Austria publist_id: '5803' status: public supervisor: - first_name: Sylvia M full_name: Cremer, Sylvia M id: 2F64EC8C-F248-11E8-B48F-1D18A9856A87 last_name: Cremer orcid: 0000-0002-2193-3868 title: Evolution of a fungal pathogen towards individual versus social immunity in ants type: dissertation user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 year: '2014' ... --- _id: '1395' abstract: - lang: eng text: In this thesis I studied various individual and social immune defences employed by the invasive garden ant Lasius neglectus mostly against entomopathogenic fungi. The first two chapters of this thesis address the phenomenon of 'social immunisation'. Social immunisation, that is the immunological protection of group members due to social contact to a pathogen-exposed nestmate, has been described in various social insect species against different types of pathogens. However, in the case of entomopathogenic fungi it has, so far, only been demonstrated that social immunisation exists at all. Its underlying mechanisms r any other properties were, however, unknown. In the first chapter of this thesis I identified the mechanistic basis of social immunisation in L. neglectus against the entomopathogenous fungus Metarhizium. I could show that nestmates of a pathogen-exposed individual contract low-level infections due to social interactions. These low-level infections are, however, non-lethal and cause an active stimulation of the immune system, which protects the nestmates upon subsequent pathogen encounters. In the second chapter of this thesis I investigated the specificity and colony level effects of social immunisation. I demonstrated that the protection conferred by social immunisation is highly specific, protecting ants only against the same pathogen strain. In addition, depending on the respective context, social immunisation may even cause fitness costs. I further showed that social immunisation crucially affects sanitary behaviour and disease dynamics within ant groups. In the third chapter of this thesis I studied the effects of the ectosymbiotic fungus Laboulbenia formicarum on its host L. neglectus. Although Laboulbeniales are the largest order of insect-parasitic fungi, research concerning host fitness consequence is sparse. I showed that highly Laboulbenia-infected ants sustain fitness costs under resource limitation, however, gain fitness benefits when exposed to an entomopathogenus fungus. These effects are probably cause by a prophylactic upregulation of behavioural as well as physiological immune defences in highly infected ants. alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Matthias full_name: Konrad, Matthias id: 46528076-F248-11E8-B48F-1D18A9856A87 last_name: Konrad citation: ama: 'Konrad M. Immune defences in ants: Effects of social immunisation and a fungal ectosymbiont in the ant Lasius neglectus. 2014.' apa: 'Konrad, M. (2014). Immune defences in ants: Effects of social immunisation and a fungal ectosymbiont in the ant Lasius neglectus. Institute of Science and Technology Austria.' chicago: 'Konrad, Matthias. “Immune Defences in Ants: Effects of Social Immunisation and a Fungal Ectosymbiont in the Ant Lasius Neglectus.” Institute of Science and Technology Austria, 2014.' ieee: 'M. Konrad, “Immune defences in ants: Effects of social immunisation and a fungal ectosymbiont in the ant Lasius neglectus,” Institute of Science and Technology Austria, 2014.' ista: 'Konrad M. 2014. Immune defences in ants: Effects of social immunisation and a fungal ectosymbiont in the ant Lasius neglectus. Institute of Science and Technology Austria.' mla: 'Konrad, Matthias. Immune Defences in Ants: Effects of Social Immunisation and a Fungal Ectosymbiont in the Ant Lasius Neglectus. Institute of Science and Technology Austria, 2014.' short: 'M. Konrad, Immune Defences in Ants: Effects of Social Immunisation and a Fungal Ectosymbiont in the Ant Lasius Neglectus, Institute of Science and Technology Austria, 2014.' date_created: 2018-12-11T11:51:46Z date_published: 2014-02-01T00:00:00Z date_updated: 2023-09-07T11:38:56Z day: '01' degree_awarded: PhD department: - _id: SyCr language: - iso: eng month: '02' oa_version: None page: '131' publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '5814' status: public supervisor: - first_name: Sylvia M full_name: Cremer, Sylvia M id: 2F64EC8C-F248-11E8-B48F-1D18A9856A87 last_name: Cremer orcid: 0000-0002-2193-3868 title: 'Immune defences in ants: Effects of social immunisation and a fungal ectosymbiont in the ant Lasius neglectus' type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2014' ... --- _id: '1402' abstract: - lang: eng text: Phosphatidylinositol (Ptdlns) is a structural phospholipid that can be phosphorylated into various lipid signaling molecules, designated polyphosphoinositides (PPIs). The reversible phosphorylation of PPIs on the 3, 4, or 5 position of inositol is performed by a set of organelle-specific kinases and phosphatases, and the characteristic head groups make these molecules ideal for regulating biological processes in time and space. In yeast and mammals, Ptdlns3P and Ptdlns(3,5)P2 play crucial roles in trafficking toward the lytic compartments, whereas the role in plants is not yet fully understood. Here we identified the role of a land plant-specific subgroup of PPI phosphatases, the suppressor of actin 2 (SAC2) to SAC5, during vauolar trafficking and morphogenesis in Arabidopsis thaliana. SAC2-SAC5 localize to the tonoplast along with Ptdlns3P, the presumable product of their activity. in SAC gain- and loss-of-function mutants, the levels of Ptdlns monophosphates and bisphosphates were changed, with opposite effects on the morphology of storage and lytic vacuoles, and the trafficking toward the vacuoles was defective. Moreover, multiple sac knockout mutants had an increased number of smaller storage and lytic vacuoles, whereas extralarge vacuoles were observed in the overexpression lines, correlating with various growth and developmental defects. The fragmented vacuolar phenotype of sac mutants could be mimicked by treating wild-type seedlings with Ptdlns(3,5)P2, corroborating that this PPI is important for vacuole morphology. Taken together, these results provide evidence that PPIs, together with their metabolic enzymes SAC2-SAC5, are crucial for vacuolar trafficking and for vacuolar morphology and function in plants. alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Petra full_name: Marhavá, Petra id: 44E59624-F248-11E8-B48F-1D18A9856A87 last_name: Marhavá citation: ama: Marhavá P. Molecular mechanisms of patterning and subcellular trafficking in Arabidopsis thaliana. 2014. apa: Marhavá, P. (2014). Molecular mechanisms of patterning and subcellular trafficking in Arabidopsis thaliana. Institute of Science and Technology Austria. chicago: Marhavá, Petra. “Molecular Mechanisms of Patterning and Subcellular Trafficking in Arabidopsis Thaliana.” Institute of Science and Technology Austria, 2014. ieee: P. Marhavá, “Molecular mechanisms of patterning and subcellular trafficking in Arabidopsis thaliana,” Institute of Science and Technology Austria, 2014. ista: Marhavá P. 2014. Molecular mechanisms of patterning and subcellular trafficking in Arabidopsis thaliana. Institute of Science and Technology Austria. mla: Marhavá, Petra. Molecular Mechanisms of Patterning and Subcellular Trafficking in Arabidopsis Thaliana. Institute of Science and Technology Austria, 2014. short: P. Marhavá, Molecular Mechanisms of Patterning and Subcellular Trafficking in Arabidopsis Thaliana, Institute of Science and Technology Austria, 2014. date_created: 2018-12-11T11:51:49Z date_published: 2014-12-01T00:00:00Z date_updated: 2023-09-07T11:39:38Z day: '01' degree_awarded: PhD department: - _id: JiFr language: - iso: eng month: '12' oa_version: None page: '90' publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '5805' status: public supervisor: - first_name: Jiří full_name: Friml, Jiří id: 4159519E-F248-11E8-B48F-1D18A9856A87 last_name: Friml orcid: 0000-0002-8302-7596 title: Molecular mechanisms of patterning and subcellular trafficking in Arabidopsis thaliana type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2014' ... --- _id: '1403' abstract: - lang: eng text: A variety of developmental and disease related processes depend on epithelial cell sheet spreading. In order to gain insight into the biophysical mechanism(s) underlying the tissue morphogenesis we studied the spreading of an epithelium during the early development of the zebrafish embryo. In zebrafish epiboly the enveloping cell layer (EVL), a simple squamous epithelium, spreads over the yolk cell to completely engulf it at the end of gastrulation. Previous studies have proposed that an actomyosin ring forming within the yolk syncytial layer (YSL) acts as purse string that through constriction along its circumference pulls on the margin of the EVL. Direct biophysical evidence for this hypothesis has however been missing. The aim of the thesis was to understand how the actomyosin ring may generate pulling forces onto the EVL and what cellular mechanism(s) may facilitate the spreading of the epithelium. Using laser ablation to measure cortical tension within the actomyosin ring we found an anisotropic tension distribution, which was highest along the circumference of the ring. However the low degree of anisotropy was incompatible with the actomyosin ring functioning as a purse string only. Additionally, we observed retrograde cortical flow from vegetal parts of the ring into the EVL margin. Interpreting the experimental data using a theoretical distribution that models the tissues as active viscous gels led us to proposen that the actomyosin ring has a twofold contribution to EVL epiboly. It not only acts as a purse string through constriction along its circumference, but in addition constriction along the width of the ring generates pulling forces through friction-resisted cortical flow. Moreover, when rendering the purse string mechanism unproductive EVL epiboly proceeded normally indicating that the flow-friction mechanism is sufficient to drive the process. Aiming to understand what cellular mechanism(s) may facilitate the spreading of the epithelium we found that tension-oriented EVL cell divisions limit tissue anisotropy by releasing tension along the division axis and promote epithelial spreading. Notably, EVL cells undergo ectopic cell fusion in conditions in which oriented-cell division is impaired or the epithelium is mechanically challenged. Taken together our study of EVL epiboly suggests a novel mechanism of force generation for actomyosin rings through friction-resisted cortical flow and highlights the importance of tension-oriented cell divisions in epithelial morphogenesis. acknowledged_ssus: - _id: SSU alternative_title: - IST Austria Thesis author: - first_name: Martin full_name: Behrndt, Martin id: 3ECECA3A-F248-11E8-B48F-1D18A9856A87 last_name: Behrndt citation: ama: Behrndt M. Forces driving epithelial spreading in zebrafish epiboly. 2014. apa: Behrndt, M. (2014). Forces driving epithelial spreading in zebrafish epiboly. IST Austria. chicago: Behrndt, Martin. “Forces Driving Epithelial Spreading in Zebrafish Epiboly.” IST Austria, 2014. ieee: M. Behrndt, “Forces driving epithelial spreading in zebrafish epiboly,” IST Austria, 2014. ista: Behrndt M. 2014. Forces driving epithelial spreading in zebrafish epiboly. IST Austria. mla: Behrndt, Martin. Forces Driving Epithelial Spreading in Zebrafish Epiboly. IST Austria, 2014. short: M. Behrndt, Forces Driving Epithelial Spreading in Zebrafish Epiboly, IST Austria, 2014. date_created: 2018-12-11T11:51:49Z date_published: 2014-08-01T00:00:00Z date_updated: 2023-10-17T12:16:58Z day: '01' department: - _id: CaHe language: - iso: eng month: '08' oa_version: None page: '91' publication_status: published publisher: IST Austria publist_id: '5804' related_material: record: - id: '2282' relation: part_of_dissertation status: public - id: '2950' relation: part_of_dissertation status: public - id: '3373' relation: part_of_dissertation status: public status: public supervisor: - first_name: Carl-Philipp J full_name: Heisenberg, Carl-Philipp J id: 39427864-F248-11E8-B48F-1D18A9856A87 last_name: Heisenberg orcid: 0000-0002-0912-4566 title: Forces driving epithelial spreading in zebrafish epiboly type: dissertation user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 year: '2014' ... --- _id: '1405' abstract: - lang: eng text: "Motivated by the analysis of highly dynamic message-passing systems, i.e. unbounded thread creation, mobility, etc. we present a framework for the analysis of depth-bounded systems. Depth-bounded systems are one of the most expressive known fragment of the π-calculus for which interesting verification problems are still decidable. Even though they are infinite state systems depth-bounded systems are well-structured, thus can be analyzed algorithmically. We give an interpretation of depth-bounded systems as graph-rewriting systems. This gives more flexibility and ease of use to apply depth-bounded systems to other type of systems like shared memory concurrency.\r\n\r\nFirst, we develop an adequate domain of limits for depth-bounded systems, a prerequisite for the effective representation of downward-closed sets. Downward-closed sets are needed by forward saturation-based algorithms to represent potentially infinite sets of states. Then, we present an abstract interpretation framework to compute the covering set of well-structured transition systems. Because, in general, the covering set is not computable, our abstraction over-approximates the actual covering set. Our abstraction captures the essence of acceleration based-algorithms while giving up enough precision to ensure convergence. We have implemented the analysis in the PICASSO tool and show that it is accurate in practice. Finally, we build some further analyses like termination using the covering set as starting point." acknowledgement: "This work was supported in part by the Austrian Science Fund NFN RiSE (Rigorous Systems Engineering) and by the ERC Advanced Grant QUAREM (Quantitative Reactve Modeling).\r\nChapter 2, 3, and 4 are joint work with Thomas A. Henzinger and Thomas Wies. Chapter 2 was published in FoSSaCS 2010 as “Forward Analysis of Depth-Bounded Processes” [112]. Chapter 3 was published in VMCAI 2012 as “Ideal Abstractions for Well-Structured Transition Systems” [114]. Chap- ter 5.1 is joint work with Kshitij Bansal, Eric Koskinen, and Thomas Wies. It was published in TACAS 2013 as “Structural Counter Abstraction” [13]. The author’s contribution in this part is mostly related to the implementation. The theory required to understand the method and its implementation is quickly recalled to make the thesis self-contained, but should not be considered as a contribution. For the details of the methods, we refer the reader to the orig- inal publication [13] and the corresponding technical report [14]. Chapter 5.2 is ongoing work with Shahram Esmaeilsabzali, Rupak Majumdar, and Thomas Wies. I also would like to thank the people who supported over the past 4 years. My advisor Thomas A. Henzinger who gave me a lot of freedom to work on projects I was interested in. My collaborators, especially Thomas Wies with whom I worked since the beginning. The members of my thesis committee, Viktor Kun- cak and Rupak Majumdar, who also agreed to advise me. Simon Aeschbacher, Pavol Cerny, Cezara Dragoi, Arjun Radhakrishna, my family, friends and col- leagues who created an enjoyable environment. " alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Damien full_name: Zufferey, Damien id: 4397AC76-F248-11E8-B48F-1D18A9856A87 last_name: Zufferey orcid: 0000-0002-3197-8736 citation: ama: Zufferey D. Analysis of dynamic message passing programs. 2013. doi:10.15479/at:ista:1405 apa: Zufferey, D. (2013). Analysis of dynamic message passing programs. Institute of Science and Technology Austria. https://doi.org/10.15479/at:ista:1405 chicago: Zufferey, Damien. “Analysis of Dynamic Message Passing Programs.” Institute of Science and Technology Austria, 2013. https://doi.org/10.15479/at:ista:1405. ieee: D. Zufferey, “Analysis of dynamic message passing programs,” Institute of Science and Technology Austria, 2013. ista: Zufferey D. 2013. Analysis of dynamic message passing programs. Institute of Science and Technology Austria. mla: Zufferey, Damien. Analysis of Dynamic Message Passing Programs. Institute of Science and Technology Austria, 2013, doi:10.15479/at:ista:1405. short: D. Zufferey, Analysis of Dynamic Message Passing Programs, Institute of Science and Technology Austria, 2013. date_created: 2018-12-11T11:51:50Z date_published: 2013-09-05T00:00:00Z date_updated: 2023-09-07T11:36:37Z day: '05' ddc: - '000' degree_awarded: PhD department: - _id: ToHe - _id: GradSch doi: 10.15479/at:ista:1405 ec_funded: 1 file: - access_level: open_access checksum: ed2d7b52933d134e8dc69d569baa284e content_type: application/pdf creator: dernst date_created: 2021-02-22T11:28:36Z date_updated: 2021-02-22T11:28:36Z file_id: '9176' file_name: 2013_Zufferey_thesis_final.pdf file_size: 1514906 relation: main_file success: 1 - access_level: closed checksum: cecc4c4b14225bee973d32e3dba91a55 content_type: application/pdf creator: cchlebak date_created: 2021-11-16T14:42:52Z date_updated: 2021-11-17T13:47:58Z file_id: '10298' file_name: 2013_Zufferey_thesis_final_pdfa.pdf file_size: 1378313 relation: main_file file_date_updated: 2021-11-17T13:47:58Z has_accepted_license: '1' language: - iso: eng main_file_link: - url: http://dzufferey.github.io/files/2013_thesis.pdf month: '09' oa: 1 oa_version: Published Version page: '134' project: - _id: 25832EC2-B435-11E9-9278-68D0E5697425 call_identifier: FWF grant_number: S 11407_N23 name: Rigorous Systems Engineering - _id: 25EE3708-B435-11E9-9278-68D0E5697425 call_identifier: FP7 grant_number: '267989' name: Quantitative Reactive Modeling publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '5802' related_material: record: - id: '2847' relation: part_of_dissertation status: public - id: '3251' relation: part_of_dissertation status: public - id: '4361' relation: part_of_dissertation status: public status: public supervisor: - first_name: Thomas A full_name: Henzinger, Thomas A id: 40876CD8-F248-11E8-B48F-1D18A9856A87 last_name: Henzinger orcid: 0000−0002−2985−7724 title: Analysis of dynamic message passing programs type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2013' ... --- _id: '1406' abstract: - lang: eng text: Epithelial spreading is a critical part of various developmental and wound repair processes. Here we use zebrafish epiboly as a model system to study the cellular and molecular mechanisms underlying the spreading of epithelial sheets. During zebrafish epiboly the enveloping cell layer (EVL), a simple squamous epithelium, spreads over the embryo to eventually cover the entire yolk cell by the end of gastrulation. The EVL leading edge is anchored through tight junctions to the yolk syncytial layer (YSL), where directly adjacent to the EVL margin a contractile actomyosin ring is formed that is thought to drive EVL epiboly. The prevalent view in the field was that the contractile ring exerts a pulling force on the EVL margin, which pulls the EVL towards the vegetal pole. However, how this force is generated and how it affects EVL morphology still remains elusive. Moreover, the cellular mechanisms mediating the increase in EVL surface area, while maintaining tissue integrity and function are still unclear. Here we show that the YSL actomyosin ring pulls on the EVL margin by two distinct force-generating mechanisms. One mechanism is based on contraction of the ring around its circumference, as previously proposed. The second mechanism is based on actomyosin retrogade flows, generating force through resistance against the substrate. The latter can function at any epiboly stage even in situations where the contraction-based mechanism is unproductive. Additionally, we demonstrate that during epiboly the EVL is subjected to anisotropic tension, which guides the orientation of EVL cell division along the main axis (animal-vegetal) of tension. The influence of tension in cell division orientation involves cell elongation and requires myosin-2 activity for proper spindle alignment. Strikingly, we reveal that tension-oriented cell divisions release anisotropic tension within the EVL and that in the absence of such divisions, EVL cells undergo ectopic fusions. We conclude that forces applied to the EVL by the action of the YSL actomyosin ring generate a tension anisotropy in the EVL that orients cell divisions, which in turn limit tissue tension increase thereby facilitating tissue spreading. acknowledged_ssus: - _id: Bio - _id: PreCl alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Pedro full_name: Campinho, Pedro id: 3AFBBC42-F248-11E8-B48F-1D18A9856A87 last_name: Campinho orcid: 0000-0002-8526-5416 citation: ama: 'Campinho P. Mechanics of zebrafish epiboly: Tension-oriented cell divisions limit anisotropic tissue tension in epithelial spreading. 2013.' apa: 'Campinho, P. (2013). Mechanics of zebrafish epiboly: Tension-oriented cell divisions limit anisotropic tissue tension in epithelial spreading. Institute of Science and Technology Austria.' chicago: 'Campinho, Pedro. “Mechanics of Zebrafish Epiboly: Tension-Oriented Cell Divisions Limit Anisotropic Tissue Tension in Epithelial Spreading.” Institute of Science and Technology Austria, 2013.' ieee: 'P. Campinho, “Mechanics of zebrafish epiboly: Tension-oriented cell divisions limit anisotropic tissue tension in epithelial spreading,” Institute of Science and Technology Austria, 2013.' ista: 'Campinho P. 2013. Mechanics of zebrafish epiboly: Tension-oriented cell divisions limit anisotropic tissue tension in epithelial spreading. Institute of Science and Technology Austria.' mla: 'Campinho, Pedro. Mechanics of Zebrafish Epiboly: Tension-Oriented Cell Divisions Limit Anisotropic Tissue Tension in Epithelial Spreading. Institute of Science and Technology Austria, 2013.' short: 'P. Campinho, Mechanics of Zebrafish Epiboly: Tension-Oriented Cell Divisions Limit Anisotropic Tissue Tension in Epithelial Spreading, Institute of Science and Technology Austria, 2013.' date_created: 2018-12-11T11:51:50Z date_published: 2013-10-01T00:00:00Z date_updated: 2023-09-07T11:36:07Z day: '01' degree_awarded: PhD department: - _id: CaHe language: - iso: eng month: '10' oa_version: None page: '123' publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '5801' status: public supervisor: - first_name: Carl-Philipp J full_name: Heisenberg, Carl-Philipp J id: 39427864-F248-11E8-B48F-1D18A9856A87 last_name: Heisenberg orcid: 0000-0002-0912-4566 title: 'Mechanics of zebrafish epiboly: Tension-oriented cell divisions limit anisotropic tissue tension in epithelial spreading' type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2013' ... --- _id: '2964' abstract: - lang: eng text: 'CA3 pyramidal neurons are important for memory formation and pattern completion in the hippocampal network. These neurons receive multiple excitatory inputs from numerous sources. Therefore, the rules of spatiotemporal integration of multiple synaptic inputs and propagation of action potentials are important to understand how CA3 neurons contribute to higher brain functions at cellular level. By using confocally targeted patch-clamp recording techniques, we investigated the biophysical properties of rat CA3 pyramidal neuron dendrites. We found two distinct dendritic domains critical for action potential initiation and propagation: In the proximal domain, action potentials initiated in the axon backpropagate actively with large amplitude and fast time course. In the distal domain, Na+-channel mediated dendritic spikes are efficiently evoked by local dendritic depolarization or waveforms mimicking synaptic events. These findings can be explained by a high Na+-to-K+ conductance density ratio of CA3 pyramidal neuron dendrites. The results challenge the prevailing view that proximal mossy fiber inputs activate CA3 pyramidal neurons more efficiently than distal perforant inputs by showing that the distal synapses trigger a different form of activity represented by dendritic spikes. The high probability of dendritic spike initiation in the distal area may enhance the computational power of CA3 pyramidal neurons in the hippocampal network. ' alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Sooyun full_name: Kim, Sooyun id: 394AB1C8-F248-11E8-B48F-1D18A9856A87 last_name: Kim citation: ama: Kim S. Active properties of hippocampal CA3 pyramidal neuron dendrites. 2012. apa: Kim, S. (2012). Active properties of hippocampal CA3 pyramidal neuron dendrites. Institute of Science and Technology Austria. chicago: Kim, Sooyun. “Active Properties of Hippocampal CA3 Pyramidal Neuron Dendrites.” Institute of Science and Technology Austria, 2012. ieee: S. Kim, “Active properties of hippocampal CA3 pyramidal neuron dendrites,” Institute of Science and Technology Austria, 2012. ista: Kim S. 2012. Active properties of hippocampal CA3 pyramidal neuron dendrites. Institute of Science and Technology Austria. mla: Kim, Sooyun. Active Properties of Hippocampal CA3 Pyramidal Neuron Dendrites. Institute of Science and Technology Austria, 2012. short: S. Kim, Active Properties of Hippocampal CA3 Pyramidal Neuron Dendrites, Institute of Science and Technology Austria, 2012. date_created: 2018-12-11T12:00:35Z date_published: 2012-06-01T00:00:00Z date_updated: 2023-09-07T11:43:51Z day: '01' degree_awarded: PhD department: - _id: PeJo - _id: GradSch language: - iso: eng month: '06' oa_version: None page: '65' publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '3755' related_material: record: - id: '3258' relation: part_of_dissertation status: public status: public supervisor: - first_name: Peter M full_name: Jonas, Peter M id: 353C1B58-F248-11E8-B48F-1D18A9856A87 last_name: Jonas orcid: 0000-0001-5001-4804 title: Active properties of hippocampal CA3 pyramidal neuron dendrites type: dissertation user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9 year: '2012' ... --- _id: '3275' abstract: - lang: eng text: 'Chemokines organize immune cell trafficking by inducing either directed (tactic) or random (kinetic) migration and by activating integrins in order to support surface adhesion (haptic). Beyond that the same chemokines can establish clearly defined functional areas in secondary lymphoid organs. Until now it is unclear how chemokines can fulfill such diverse functions. One decisive prerequisite to explain these capacities is to know how chemokines are presented in tissue. In theory chemokines could occur either soluble or immobilized, and could be distributed either homogenously or as a concentration gradient. To dissect if and how the presenting mode of chemokines influences immune cells, I tested the response of dendritic cells (DCs) to differentially displayed chemokines. DCs are antigen presenting cells that reside in the periphery and migrate into draining lymph nodes (LNs) once exposed to inflammatory stimuli to activate naïve T cells. DCs are guided to and within the LN by the chemokine receptor CCR7, which has two ligands, the chemokines CCL19 and CCL21. Both CCR7 ligands are expressed by fibroblastic reticular cells in the LN, but differ in their ability to bind to heparan sulfate residues. CCL21 has a highly charged C-terminal extension, which mediates binding to anionic surfaces, whereas CCL19 is lacking such residues and likely distributes as a soluble molecule. This study shows that surface-bound CCL21 causes random, haptokinetic DC motility, which is confined to the chemokine coated area by insideout activation of β2 integrins that mediate cell binding to the surface. CCL19 on the other hand forms concentration gradients which trigger directional, chemotactic movement, but no surface adhesion. In addition DCs can actively manipulate this system by recruiting and activating serine proteases on their surfaces, which create - by proteolytically removing the adhesive C-terminus - a solubilized variant of CCL21 that functionally resembles CCL19. By generating a CCL21 concentration gradient DCs establish a positive feedback loop to recruit further DCs from the periphery to the CCL21 coated region. In addition DCs can sense chemotactic gradients as well as immobilized haptokinetic fields at the same time and integrate these signals. The result is chemotactically biased haptokinesis - directional migration confined to a chemokine coated track or area - which could explain the dynamic but spatially tightly controlled swarming leukocyte locomotion patterns that have been observed in lymphatic organs by intravital microscopists. The finding that DCs can approach soluble cues in a non-adhesive manner while they attach to surfaces coated with immobilized cues raises the question how these cells transmit intracellular forces to the environment, especially in the non-adherent migration mode. In order to migrate, cells have to generate and transmit force to the extracellular substrate. Force transmission is the prerequisite to procure an expansion of the leading edge and a forward motion of the whole cell body. In the current conceptions actin polymerization at the leading edge is coupled to extracellular ligands via the integrin family of transmembrane receptors, which allows the transmission of intracellular force. Against the paradigm of force transmission during migration, leukocytes, like DCs, are able to migrate in threedimensional environments without using integrin transmembrane receptors (Lämmermann et al., 2008). This reflects the biological function of leukocytes, as they can invade almost all tissues, whereby their migration has to be independent from the extracellular environment. How the cells can achieve this is unclear. For this study I examined DC migration in a defined threedimensional environment and highlighted actin-dynamics with the probe Lifeact-GFP. The result was that chemotactic DCs can switch between integrin-dependent and integrin- independent locomotion and can thereby adapt to the adhesive properties of their environment. If the cells are able to couple their actin cytoskeleton to the substrate, actin polymerization is entirely converted into protrusion. Without coupling the actin cortex undergoes slippage and retrograde actin flow can be observed. But retrograde actin flow can be completely compensated by higher actin polymerization rate keeping the migration velocity and the shape of the cells unaltered. Mesenchymal cells like fibroblast cannot balance the loss of adhesive interaction, cannot protrude into open space and, therefore, strictly depend on integrinmediated force coupling. This leukocyte specific phenomenon of “adaptive force transmission” endows these cells with the unique ability to transit and invade almost every type of tissue. ' acknowledgement: "I would like to express my sincere gratitude to the following people who made with their continuous support and encouragement this thesis possible: First, I want to thank Prof. Dr. Michael Sixt for his excellent supervision and mentoring, especially for the nice, relaxed working atmosphere, a lot of brilliant ideas and the freedom to work in my own way.\r\n\r\nProf. Dr. Reinhard Fässler for his constant support of the Sixt lab and for providing excellent working conditions. \r\n\r\nProf. Dr. Sanjiv Luther and Prof. Dr. Tobias Bollenbach for agreeing to be member of my thesis committee and to evaluate my work.\r\n\r\nDr. Walther Göhring, Carmen Schmitz, the Recombinant Protein Production core facility and the animal care takers for providing the “infrastructure” for this thesis. \r\n\r\nProf. Dr. Daniel Legler, Markus Bruckner and Dr. Julien Polleux for very fruitful collaborations and discussions.\r\n\r\nMy labmates for their help, a lot of discussions and to make the Sixt lab to a convenient place to work : Karin Hirsch, Tim Lämmeramnn, Holger Pflicke, Jörg Renkawitz, Michele Weber and Alexander Eichner All members of the Department of Molecular Medicine for their help. Especially I want to thank Sarah Schmidt, Karin Hirsch and Raphael Ruppert for their friendship, nice chats and their uncensored point of view. " alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Kathrin full_name: Schumann, Kathrin id: F44D762E-4F9D-11E9-B64C-9EB26CEFFB5F last_name: Schumann citation: ama: Schumann K. The role of chemotactic gradients in dendritic cell migration. 2011. apa: Schumann, K. (2011). The role of chemotactic gradients in dendritic cell migration. Institute of Science and Technology Austria. chicago: Schumann, Kathrin. “The Role of Chemotactic Gradients in Dendritic Cell Migration.” Institute of Science and Technology Austria, 2011. ieee: K. Schumann, “The role of chemotactic gradients in dendritic cell migration,” Institute of Science and Technology Austria, 2011. ista: Schumann K. 2011. The role of chemotactic gradients in dendritic cell migration. Institute of Science and Technology Austria. mla: Schumann, Kathrin. The Role of Chemotactic Gradients in Dendritic Cell Migration. Institute of Science and Technology Austria, 2011. short: K. Schumann, The Role of Chemotactic Gradients in Dendritic Cell Migration, Institute of Science and Technology Austria, 2011. date_created: 2018-12-11T12:02:24Z date_published: 2011-03-01T00:00:00Z date_updated: 2023-09-07T11:31:48Z day: '01' ddc: - '570' - '579' degree_awarded: PhD department: - _id: MiSi file: - access_level: closed checksum: e69eee6252660f0b694a2ea8923ddc72 content_type: application/pdf creator: dernst date_created: 2019-03-26T08:12:21Z date_updated: 2020-07-14T12:46:06Z file_id: '6177' file_name: 2011_Thesis_Kathrin_Schumann.pdf file_size: 4487708 relation: main_file - access_level: open_access checksum: 71727d63f424b5b446f68f4b87ecadc0 content_type: application/pdf creator: dernst date_created: 2021-02-22T11:24:30Z date_updated: 2021-02-22T11:24:30Z file_id: '9175' file_name: 2011_Thesis_Schumann_noS.pdf file_size: 4313127 relation: main_file success: 1 file_date_updated: 2021-02-22T11:24:30Z has_accepted_license: '1' language: - iso: eng month: '03' oa: 1 oa_version: Published Version page: '141' publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '3371' pubrep_id: '11' status: public supervisor: - first_name: Michael K full_name: Sixt, Michael K id: 41E9FBEA-F248-11E8-B48F-1D18A9856A87 last_name: Sixt orcid: 0000-0002-6620-9179 title: The role of chemotactic gradients in dendritic cell migration type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2011' ... --- _id: '3273' alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Jean-Léon full_name: Maître, Jean-Léon id: 48F1E0D8-F248-11E8-B48F-1D18A9856A87 last_name: Maître orcid: 0000-0002-3688-1474 citation: ama: Maître J-L. Mechanics of adhesion and de‐adhesion in zebrafish germ layer progenitors. 2011. apa: Maître, J.-L. (2011). Mechanics of adhesion and de‐adhesion in zebrafish germ layer progenitors. Institute of Science and Technology Austria. chicago: Maître, Jean-Léon. “Mechanics of Adhesion and De‐adhesion in Zebrafish Germ Layer Progenitors.” Institute of Science and Technology Austria, 2011. ieee: J.-L. Maître, “Mechanics of adhesion and de‐adhesion in zebrafish germ layer progenitors,” Institute of Science and Technology Austria, 2011. ista: Maître J-L. 2011. Mechanics of adhesion and de‐adhesion in zebrafish germ layer progenitors. Institute of Science and Technology Austria. mla: Maître, Jean-Léon. Mechanics of Adhesion and De‐adhesion in Zebrafish Germ Layer Progenitors. Institute of Science and Technology Austria, 2011. short: J.-L. Maître, Mechanics of Adhesion and De‐adhesion in Zebrafish Germ Layer Progenitors, Institute of Science and Technology Austria, 2011. date_created: 2018-12-11T12:02:23Z date_published: 2011-12-12T00:00:00Z date_updated: 2023-09-07T11:30:16Z day: '12' degree_awarded: PhD department: - _id: CaHe language: - iso: eng month: '12' oa_version: None publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '3373' status: public supervisor: - first_name: Carl-Philipp J full_name: Heisenberg, Carl-Philipp J id: 39427864-F248-11E8-B48F-1D18A9856A87 last_name: Heisenberg orcid: 0000-0002-0912-4566 title: Mechanics of adhesion and de‐adhesion in zebrafish germ layer progenitors type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2011' ... --- _id: '3962' alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Holger full_name: Pflicke, Holger id: CAA57A9A-5B61-11E9-B130-E0C1E1F2C83D last_name: Pflicke citation: ama: Pflicke H.   Dendritic cell migration across basement membranes in the skin. 2010. apa: Pflicke, H. (2010).   Dendritic cell migration across basement membranes in the skin. Institute of Science and Technology Austria. chicago: Pflicke, Holger. “  Dendritic Cell Migration across Basement Membranes in the Skin.” Institute of Science and Technology Austria, 2010. ieee: H. Pflicke, “  Dendritic cell migration across basement membranes in the skin,” Institute of Science and Technology Austria, 2010. ista: Pflicke H. 2010.   Dendritic cell migration across basement membranes in the skin. Institute of Science and Technology Austria. mla: Pflicke, Holger.   Dendritic Cell Migration across Basement Membranes in the Skin. Institute of Science and Technology Austria, 2010. short: H. Pflicke,   Dendritic Cell Migration across Basement Membranes in the Skin, Institute of Science and Technology Austria, 2010. date_created: 2018-12-11T12:06:08Z date_published: 2010-07-01T00:00:00Z date_updated: 2023-09-07T11:28:47Z day: '01' degree_awarded: PhD department: - _id: CaHe - _id: GradSch language: - iso: eng month: '07' oa_version: None publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '2165' status: public supervisor: - first_name: Carl-Philipp J full_name: Heisenberg, Carl-Philipp J id: 39427864-F248-11E8-B48F-1D18A9856A87 last_name: Heisenberg orcid: 0000-0002-0912-4566 title: "\uFEFF\uFEFFDendritic cell migration across basement membranes in the skin" type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2010' ...