---
_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
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- iso: eng
month: '10'
oa: 1
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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:
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checksum: fc60585c9eaad868ac007004ef130908
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date_updated: 2020-07-14T12:47:25Z
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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:
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checksum: 1406a681cb737508234fde34766be2c2
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creator: system
date_created: 2018-12-12T10:11:26Z
date_updated: 2020-07-14T12:44:34Z
file_id: '4880'
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file_size: 1028586
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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:
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checksum: a0fc5c26a89c0ea759947ffba87d0d8f
content_type: application/pdf
creator: dernst
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date_updated: 2020-07-14T12:47:27Z
file_id: '6292'
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file_size: 3025175
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checksum: af531e921a7f64a9e0af4cd8783b2226
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creator: dernst
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date_updated: 2021-02-22T13:45:59Z
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file_name: 2017_Payne_Thesis.pdf
file_size: 3111536
relation: main_file
success: 1
file_date_updated: 2021-02-22T13:45:59Z
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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
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oa_version: Published Version
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pubrep_id: '862'
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- 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
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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
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checksum: c62257a7bff0c5f39e1abffc6bfcca5c
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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
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user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
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...
---
_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'
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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:
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page: '93'
publication_identifier:
issn:
- 2663-337X
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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:
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date_created: 2019-04-05T09:03:20Z
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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:
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date_created: 2018-12-12T10:07:55Z
date_updated: 2020-07-14T12:48:18Z
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date_created: 2019-04-05T08:43:24Z
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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
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relation: source_file
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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:
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checksum: 4993cdd5382295758ecc3ecbd2a9aaff
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date_created: 2019-04-05T07:53:04Z
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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
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file_size: 14596191
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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
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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
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date_updated: 2019-08-13T10:55:35Z
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file_name: Thesis_JSchwarz_final.pdf
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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
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creator: dernst
date_created: 2021-02-22T11:36:34Z
date_updated: 2021-02-22T11:36:34Z
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file_size: 2227916
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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
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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
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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
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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'
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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
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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:
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creator: dernst
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success: 1
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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'
...