TY - JOUR
AB - Pancreatic islets play an essential role in regulating blood glucose level. Although the molecular pathways underlying islet cell differentiation are beginning to be resolved, the cellular basis of islet morphogenesis and fate allocation remain unclear. By combining unbiased and targeted lineage tracing, we address the events leading to islet formation in the mouse. From the statistical analysis of clones induced at multiple embryonic timepoints, here we show that, during the secondary transition, islet formation involves the aggregation of multiple equipotent endocrine progenitors that transition from a phase of stochastic amplification by cell division into a phase of sublineage restriction and limited islet fission. Together, these results explain quantitatively the heterogeneous size distribution and degree of polyclonality of maturing islets, as well as dispersion of progenitors within and between islets. Further, our results show that, during the secondary transition, α- and β-cells are generated in a contemporary manner. Together, these findings provide insight into the cellular basis of islet development.
AU - Sznurkowska, Magdalena K.
AU - Hannezo, Edouard B
AU - Azzarelli, Roberta
AU - Chatzeli, Lemonia
AU - Ikeda, Tatsuro
AU - Yoshida, Shosei
AU - Philpott, Anna
AU - Simons, Benjamin D
ID - 8669
JF - Nature Communications
TI - Tracing the cellular basis of islet specification in mouse pancreas
VL - 11
ER -
TY - JOUR
AB - The α–z Rényi relative entropies are a two-parameter family of Rényi relative entropies that are quantum generalizations of the classical α-Rényi relative entropies. In the work [Adv. Math. 365, 107053 (2020)], we decided the full range of (α, z) for which the data processing inequality (DPI) is valid. In this paper, we give algebraic conditions for the equality in DPI. For the full range of parameters (α, z), we give necessary conditions and sufficient conditions. For most parameters, we give equivalent conditions. This generalizes and strengthens the results of Leditzky et al. [Lett. Math. Phys. 107, 61–80 (2017)].
AU - Zhang, Haonan
ID - 8670
IS - 10
JF - Journal of Mathematical Physics
SN - 00222488
TI - Equality conditions of data processing inequality for α-z Rényi relative entropies
VL - 61
ER -
TY - JOUR
AB - We study relations between evidence theory and S-approximation spaces. Both theories have their roots in the analysis of Dempsterchr('39')s multivalued mappings and lower and upper probabilities, and have close relations to rough sets. We show that an S-approximation space, satisfying a monotonicity condition, can induce a natural belief structure which is a fundamental block in evidence theory. We also demonstrate that one can induce a natural belief structure on one set, given a belief structure on another set, if the two sets are related by a partial monotone S-approximation space.
AU - Shakiba, A.
AU - Goharshady, Amir Kafshdar
AU - Hooshmandasl, M.R.
AU - Alambardar Meybodi, M.
ID - 8671
IS - 2
JF - Iranian Journal of Mathematical Sciences and Informatics
SN - 17354463
TI - A note on belief structures and s-approximation spaces
VL - 15
ER -
TY - JOUR
AB - Cell fate transitions are key to development and homeostasis. It is thus essential to understand the cellular mechanisms controlling fate transitions. Cell division has been implicated in fate decisions in many stem cell types, including neuronal and epithelial progenitors. In other stem cells, such as embryonic stem (ES) cells, the role of division remains unclear. Here, we show that exit from naive pluripotency in mouse ES cells generally occurs after a division. We further show that exit timing is strongly correlated between sister cells, which remain connected by cytoplasmic bridges long after division, and that bridge abscission progressively accelerates as cells exit naive pluripotency. Finally, interfering with abscission impairs naive pluripotency exit, and artificially inducing abscission accelerates it. Altogether, our data indicate that a switch in the division machinery leading to faster abscission regulates pluripotency exit. Our study identifies abscission as a key cellular process coupling cell division to fate transitions.
AU - Chaigne, Agathe
AU - Labouesse, Céline
AU - White, Ian J.
AU - Agnew, Meghan
AU - Hannezo, Edouard B
AU - Chalut, Kevin J.
AU - Paluch, Ewa K.
ID - 8672
IS - 2
JF - Developmental Cell
SN - 15345807
TI - Abscission couples cell division to embryonic stem cell fate
VL - 55
ER -
TY - JOUR
AB - Extrasynaptic actions of glutamate are limited by high-affinity transporters expressed by perisynaptic astroglial processes (PAPs): this helps maintain point-to-point transmission in excitatory circuits. Memory formation in the brain is associated with synaptic remodeling, but how this affects PAPs and therefore extrasynaptic glutamate actions is poorly understood. Here, we used advanced imaging methods, in situ and in vivo, to find that a classical synaptic memory mechanism, long-term potentiation (LTP), triggers withdrawal of PAPs from potentiated synapses. Optical glutamate sensors combined with patch-clamp and 3D molecular localization reveal that LTP induction thus prompts spatial retreat of astroglial glutamate transporters, boosting glutamate spillover and NMDA-receptor-mediated inter-synaptic cross-talk. The LTP-triggered PAP withdrawal involves NKCC1 transporters and the actin-controlling protein cofilin but does not depend on major Ca2+-dependent cascades in astrocytes. We have therefore uncovered a mechanism by which a memory trace at one synapse could alter signal handling by multiple neighboring connections.
AU - Henneberger, Christian
AU - Bard, Lucie
AU - Panatier, Aude
AU - Reynolds, James P.
AU - Kopach, Olga
AU - Medvedev, Nikolay I.
AU - Minge, Daniel
AU - Herde, Michel K.
AU - Anders, Stefanie
AU - Kraev, Igor
AU - Heller, Janosch P.
AU - Rama, Sylvain
AU - Zheng, Kaiyu
AU - Jensen, Thomas P.
AU - Sanchez-Romero, Inmaculada
AU - Jackson, Colin J.
AU - Janovjak, Harald L
AU - Ottersen, Ole Petter
AU - Nagelhus, Erlend Arnulf
AU - Oliet, Stephane H.R.
AU - Stewart, Michael G.
AU - Nägerl, U. VAlentin
AU - Rusakov, Dmitri A.
ID - 8674
IS - 5
JF - Neuron
SN - 08966273
TI - LTP induction boosts glutamate spillover by driving withdrawal of perisynaptic astroglia
VL - 108
ER -
TY - JOUR
AB - A central goal of artificial intelligence in high-stakes decision-making applications is to design a single algorithm that simultaneously expresses generalizability by learning coherent representations of their world and interpretable explanations of its dynamics. Here, we combine brain-inspired neural computation principles and scalable deep learning architectures to design compact neural controllers for task-specific compartments of a full-stack autonomous vehicle control system. We discover that a single algorithm with 19 control neurons, connecting 32 encapsulated input features to outputs by 253 synapses, learns to map high-dimensional inputs into steering commands. This system shows superior generalizability, interpretability and robustness compared with orders-of-magnitude larger black-box learning systems. The obtained neural agents enable high-fidelity autonomy for task-specific parts of a complex autonomous system.
AU - Lechner, Mathias
AU - Hasani, Ramin
AU - Amini, Alexander
AU - Henzinger, Thomas A
AU - Rus, Daniela
AU - Grosu, Radu
ID - 8679
JF - Nature Machine Intelligence
TI - Neural circuit policies enabling auditable autonomy
VL - 2
ER -
TY - JOUR
AB - Animal development entails the organization of specific cell types in space and time, and spatial patterns must form in a robust manner. In the zebrafish spinal cord, neural progenitors form stereotypic patterns despite noisy morphogen signaling and large-scale cellular rearrangements during morphogenesis and growth. By directly measuring adhesion forces and preferences for three types of endogenous neural progenitors, we provide evidence for the differential adhesion model in which differences in intercellular adhesion mediate cell sorting. Cell type–specific combinatorial expression of different classes of cadherins (N-cadherin, cadherin 11, and protocadherin 19) results in homotypic preference ex vivo and patterning robustness in vivo. Furthermore, the differential adhesion code is regulated by the sonic hedgehog morphogen gradient. We propose that robust patterning during tissue morphogenesis results from interplay between adhesion-based self-organization and morphogen-directed patterning.
AU - Tsai, Tony Y.-C.
AU - Sikora, Mateusz K
AU - Xia, Peng
AU - Colak-Champollion, Tugba
AU - Knaut, Holger
AU - Heisenberg, Carl-Philipp J
AU - Megason, Sean G.
ID - 8680
IS - 6512
JF - Science
KW - Multidisciplinary
SN - 0036-8075
TI - An adhesion code ensures robust pattern formation during tissue morphogenesis
VL - 370
ER -
TY - GEN
AB - It is known that the Brauer--Manin obstruction to the Hasse principle is vacuous for smooth Fano hypersurfaces of dimension at least 3 over any number field. Moreover, for such varieties it follows from a general conjecture of Colliot-Thélène that the Brauer--Manin obstruction to the Hasse principle should be the only one, so that the Hasse principle is expected to hold. Working over the field of rational numbers and ordering Fano hypersurfaces of fixed degree and dimension by height, we prove that almost every such hypersurface satisfies the Hasse principle provided that the dimension is at least 3. This proves a conjecture of Poonen and Voloch in every case except for cubic surfaces.
AU - Browning, Timothy D
AU - Boudec, Pierre Le
AU - Sawin, Will
ID - 8682
T2 - arXiv
TI - The Hasse principle for random Fano hypersurfaces
ER -
TY - JOUR
AB - Given l>2ν>2d≥4, we prove the persistence of a Cantor--family of KAM tori of measure O(ε1/2−ν/l) for any non--degenerate nearly integrable Hamiltonian system of class Cl(D×Td), where D⊂Rd is a bounded domain, provided that the size ε of the perturbation is sufficiently small. This extends a result by D. Salamon in \cite{salamon2004kolmogorov} according to which we do have the persistence of a single KAM torus in the same framework. Moreover, it is well--known that, for the persistence of a single torus, the regularity assumption can not be improved.
AU - Koudjinan, Edmond
ID - 8691
IS - 6
JF - Journal of Differential Equations
KW - Analysis
SN - 0022-0396
TI - A KAM theorem for finitely differentiable Hamiltonian systems
VL - 269
ER -
TY - JOUR
AB - We develop algorithms and techniques to compute rigorous bounds for finite pieces of orbits of the critical points, for intervals of parameter values, in the quadratic family of one-dimensional maps fa(x)=a−x2. We illustrate the effectiveness of our approach by constructing a dynamically defined partition 𝒫 of the parameter interval Ω=[1.4,2] into almost 4×106 subintervals, for each of which we compute to high precision the orbits of the critical points up to some time N and other dynamically relevant quantities, several of which can vary greatly, possibly spanning several orders of magnitude. We also subdivide 𝒫 into a family 𝒫+ of intervals, which we call stochastic intervals, and a family 𝒫− of intervals, which we call regular intervals. We numerically prove that each interval ω∈𝒫+ has an escape time, which roughly means that some iterate of the critical point taken over all the parameters in ω has considerable width in the phase space. This suggests, in turn, that most parameters belonging to the intervals in 𝒫+ are stochastic and most parameters belonging to the intervals in 𝒫− are regular, thus the names. We prove that the intervals in 𝒫+ occupy almost 90% of the total measure of Ω. The software and the data are freely available at http://www.pawelpilarczyk.com/quadr/, and a web page is provided for carrying out the calculations. The ideas and procedures can be easily generalized to apply to other parameterized families of dynamical systems.
AU - Golmakani, Ali
AU - Koudjinan, Edmond
AU - Luzzatto, Stefano
AU - Pilarczyk, Pawel
ID - 8694
IS - 7
JF - Chaos
TI - Rigorous numerics for critical orbits in the quadratic family
VL - 30
ER -
TY - GEN
AB - A look at international activities on Open Science reveals a broad spectrum from individual institutional policies to national action plans. The present Recommendations for a National Open Science Strategy in Austria are based on these international initiatives and present practical considerations for their coordinated implementation with regard to strategic developments in research, technology and innovation (RTI) in Austria until 2030. They are addressed to all relevant actors in the RTI system, in particular to Research Performing Organisations, Research Funding Organisations, Research Policy, memory institutions such as Libraries and Researchers. The recommendation paper was developed from 2018 to 2020 by the OANA working group "Open Science Strategy" and published for the first time in spring 2020 for a public consultation. The now available final version of the recommendation document, which contains feedback and comments from the consultation, is intended to provide an impetus for further discussion and implementation of Open Science in Austria and serves as a contribution and basis for a potential national Open Science Strategy in Austria. The document builds on the diverse expertise of the authors (academia, administration, library and archive, information technology, science policy, funding system, etc.) and reflects their personal experiences and opinions.
AU - Mayer, Katja
AU - Rieck, Katharina
AU - Reichmann, Stefan
AU - Danowski, Patrick
AU - Graschopf, Anton
AU - König, Thomas
AU - Kraker, Peter
AU - Lehner, Patrick
AU - Reckling, Falk
AU - Ross-Hellauer, Tony
AU - Spichtinger, Daniel
AU - Tzatzanis, Michalis
AU - Schürz, Stefanie
ID - 8695
TI - Empfehlungen für eine nationale Open Science Strategie in Österreich / Recommendations for a National Open Science Strategy in Austria
ER -
TY - JOUR
AB - In the computation of the material properties of random alloys, the method of 'special quasirandom structures' attempts to approximate the properties of the alloy on a finite volume with higher accuracy by replicating certain statistics of the random atomic lattice in the finite volume as accurately as possible. In the present work, we provide a rigorous justification for a variant of this method in the framework of the Thomas–Fermi–von Weizsäcker (TFW) model. Our approach is based on a recent analysis of a related variance reduction method in stochastic homogenization of linear elliptic PDEs and the locality properties of the TFW model. Concerning the latter, we extend an exponential locality result by Nazar and Ortner to include point charges, a result that may be of independent interest.
AU - Fischer, Julian L
AU - Kniely, Michael
ID - 8697
IS - 11
JF - Nonlinearity
SN - 09517715
TI - Variance reduction for effective energies of random lattices in the Thomas-Fermi-von Weizsäcker model
VL - 33
ER -
TY - JOUR
AB - The brain represents and reasons probabilistically about complex stimuli and motor actions using a noisy, spike-based neural code. A key building block for such neural computations, as well as the basis for supervised and unsupervised learning, is the ability to estimate the surprise or likelihood of incoming high-dimensional neural activity patterns. Despite progress in statistical modeling of neural responses and deep learning, current approaches either do not scale to large neural populations or cannot be implemented using biologically realistic mechanisms. Inspired by the sparse and random connectivity of real neuronal circuits, we present a model for neural codes that accurately estimates the likelihood of individual spiking patterns and has a straightforward, scalable, efficient, learnable, and realistic neural implementation. This model’s performance on simultaneously recorded spiking activity of >100 neurons in the monkey visual and prefrontal cortices is comparable with or better than that of state-of-the-art models. Importantly, the model can be learned using a small number of samples and using a local learning rule that utilizes noise intrinsic to neural circuits. Slower, structural changes in random connectivity, consistent with rewiring and pruning processes, further improve the efficiency and sparseness of the resulting neural representations. Our results merge insights from neuroanatomy, machine learning, and theoretical neuroscience to suggest random sparse connectivity as a key design principle for neuronal computation.
AU - Maoz, Ori
AU - Tkačik, Gašper
AU - Esteki, Mohamad Saleh
AU - Kiani, Roozbeh
AU - Schneidman, Elad
ID - 8698
IS - 40
JF - Proceedings of the National Academy of Sciences of the United States of America
SN - 00278424
TI - Learning probabilistic neural representations with randomly connected circuits
VL - 117
ER -
TY - JOUR
AB - In the high spin–orbit-coupled Sr2IrO4, the high sensitivity of the ground state to the details of the local lattice structure shows a large potential for the manipulation of the functional properties by inducing local lattice distortions. We use epitaxial strain to modify the Ir–O bond geometry in Sr2IrO4 and perform momentum-dependent resonant inelastic X-ray scattering (RIXS) at the metal and at the ligand sites to unveil the response of the low-energy elementary excitations. We observe that the pseudospin-wave dispersion for tensile-strained Sr2IrO4 films displays large softening along the [h,0] direction, while along the [h,h] direction it shows hardening. This evolution reveals a renormalization of the magnetic interactions caused by a strain-driven cross-over from anisotropic to isotropic interactions between the magnetic moments. Moreover, we detect dispersive electron–hole pair excitations which shift to lower (higher) energies upon compressive (tensile) strain, manifesting a reduction (increase) in the size of the charge gap. This behavior shows an intimate coupling between charge excitations and lattice distortions in Sr2IrO4, originating from the modified hopping elements between the t2g orbitals. Our work highlights the central role played by the lattice degrees of freedom in determining both the pseudospin and charge excitations of Sr2IrO4 and provides valuable information toward the control of the ground state of complex oxides in the presence of high spin–orbit coupling.
AU - Paris, Eugenio
AU - Tseng, Yi
AU - Paerschke, Ekaterina
AU - Zhang, Wenliang
AU - Upton, Mary H
AU - Efimenko, Anna
AU - Rolfs, Katharina
AU - McNally, Daniel E
AU - Maurel, Laura
AU - Naamneh, Muntaser
AU - Caputo, Marco
AU - Strocov, Vladimir N
AU - Wang, Zhiming
AU - Casa, Diego
AU - Schneider, Christof W
AU - Pomjakushina, Ekaterina
AU - Wohlfeld, Krzysztof
AU - Radovic, Milan
AU - Schmitt, Thorsten
ID - 8699
IS - 40
JF - Proceedings of the National Academy of Sciences of the United States of America
SN - 00278424
TI - Strain engineering of the charge and spin-orbital interactions in Sr2IrO4
VL - 117
ER -
TY - JOUR
AB - Translation termination is a finishing step of protein biosynthesis. The significant role in this process belongs not only to protein factors of translation termination but also to the nearest nucleotide environment of stop codons. There are numerous descriptions of stop codons readthrough, which is due to specific nucleotide sequences behind them. However, represented data are segmental and don’t explain the mechanism of the nucleotide context influence on translation termination. It is well known that stop codon UAA usage is preferential for A/T-rich genes, and UAG, UGA—for G/C-rich genes, which is related to an expression level of these genes. We investigated the connection between a frequency of nucleotides occurrence in 3' area of stop codons in the human genome and their influence on translation termination efficiency. We found that 3' context motif, which is cognate to the sequence of a stop codon, stimulates translation termination. At the same time, the nucleotide composition of 3' sequence that differs from stop codon, decreases translation termination efficiency.
AU - Sokolova, E. E.
AU - Vlasov, Petr
AU - Egorova, T. V.
AU - Shuvalov, A. V.
AU - Alkalaeva, E. Z.
ID - 8700
IS - 5
JF - Molecular Biology
SN - 00268933
TI - The influence of A/G composition of 3' stop codon contexts on translation termination efficiency in eukaryotes
VL - 54
ER -
TY - JOUR
AB - Translation termination is a finishing step of protein biosynthesis. The significant role in this process belongs not only to protein factors of translation termination but also to the nearest nucleotide environment of stop codons. There are numerous descriptions of stop codons readthrough, which is due to specific nucleotide sequences behind them. However, represented data are segmental and don’t explain the mechanism of the nucleotide context influence on translation termination. It is well known that stop codon UAA usage is preferential for A/T-rich genes, and UAG, UGA—for G/C-rich genes, which is related to an expression level of these genes. We investigated the connection between a frequency of nucleotides occurrence in 3' area of stop codons in the human genome and their influence on translation termination efficiency. We found that 3' context motif, which is cognate to the sequence of a stop codon, stimulates translation termination. At the same time, the nucleotide composition of 3' sequence that differs from stop codon, decreases translation termination efficiency.
AU - Sokolova, E. E.
AU - Vlasov, Petr
AU - Egorova, T. V.
AU - Shuvalov, A. V.
AU - Alkalaeva, E. Z.
ID - 8701
IS - 5
JF - Molekuliarnaia biologiia
SN - 00268984
TI - The influence of A/G composition of 3' stop codon contexts on translation termination efficiency in eukaryotes
VL - 54
ER -
TY - CONF
AB - Even though Delaunay originally introduced his famous triangulations in the case of infinite point sets with translational periodicity, a software that computes such triangulations in the general case is not yet available, to the best of our knowledge. Combining and generalizing previous work, we present a practical algorithm for computing such triangulations. The algorithm has been implemented and experiments show that its performance is as good as the one of the CGAL package, which is restricted to cubic periodicity.
AU - Osang, Georg F
AU - Rouxel-Labbé, Mael
AU - Teillaud, Monique
ID - 8703
SN - 18688969
T2 - 28th Annual European Symposium on Algorithms
TI - Generalizing CGAL periodic Delaunay triangulations
VL - 173
ER -
TY - CONF
AB - Traditional robotic control suits require profound task-specific knowledge for designing, building and testing control software. The rise of Deep Learning has enabled end-to-end solutions to be learned entirely from data, requiring minimal knowledge about the application area. We design a learning scheme to train end-to-end linear dynamical systems (LDS)s by gradient descent in imitation learning robotic domains. We introduce a new regularization loss component together with a learning algorithm that improves the stability of the learned autonomous system, by forcing the eigenvalues of the internal state updates of an LDS to be negative reals. We evaluate our approach on a series of real-life and simulated robotic experiments, in comparison to linear and nonlinear Recurrent Neural Network (RNN) architectures. Our results show that our stabilizing method significantly improves test performance of LDS, enabling such linear models to match the performance of contemporary nonlinear RNN architectures. A video of the obstacle avoidance performance of our method on a mobile robot, in unseen environments, compared to other methods can be viewed at https://youtu.be/mhEsCoNao5E.
AU - Lechner, Mathias
AU - Hasani, Ramin
AU - Rus, Daniela
AU - Grosu, Radu
ID - 8704
SN - 10504729
T2 - Proceedings - IEEE International Conference on Robotics and Automation
TI - Gershgorin loss stabilizes the recurrent neural network compartment of an end-to-end robot learning scheme
ER -
TY - JOUR
AB - We consider the quantum mechanical many-body problem of a single impurity particle immersed in a weakly interacting Bose gas. The impurity interacts with the bosons via a two-body potential. We study the Hamiltonian of this system in the mean-field limit and rigorously show that, at low energies, the problem is well described by the Fröhlich polaron model.
AU - Mysliwy, Krzysztof
AU - Seiringer, Robert
ID - 8705
IS - 12
JF - Annales Henri Poincare
SN - 1424-0637
TI - Microscopic derivation of the Fröhlich Hamiltonian for the Bose polaron in the mean-field limit
VL - 21
ER -
TY - JOUR
AB - As part of the Austrian Transition to Open Access (AT2OA) project, subproject TP1-B is working on designing a monitoring solution for the output of Open Access publications in Austria. This report on a potential Open Access monitoring approach in Austria is one of the results of these efforts and can serve as a basis for discussion on an international level.
AU - Danowski, Patrick
AU - Ferus, Andreas
AU - Hikl, Anna-Laetitia
AU - McNeill, Gerda
AU - Miniberger, Clemens
AU - Reding, Steve
AU - Zarka, Tobias
AU - Zojer, Michael
ID - 8706
IS - 2
JF - Mitteilungen der Vereinigung Österreichischer Bibliothekarinnen und Bibliothekare
TI - „Recommendation“ for the further procedure for open access monitoring. Deliverable of the AT2OA subproject TP1-B
VL - 73
ER -