@article{7436, abstract = {For an ordinary K3 surface over an algebraically closed field of positive characteristic we show that every automorphism lifts to characteristic zero. Moreover, we show that the Fourier-Mukai partners of an ordinary K3 surface are in one-to-one correspondence with the Fourier-Mukai partners of the geometric generic fiber of its canonical lift. We also prove that the explicit counting formula for Fourier-Mukai partners of the K3 surfaces with Picard rank two and with discriminant equal to minus of a prime number, in terms of the class number of the prime, holds over a field of positive characteristic as well. We show that the image of the derived autoequivalence group of a K3 surface of finite height in the group of isometries of its crystalline cohomology has index at least two. Moreover, we provide a conditional upper bound on the kernel of this natural cohomological descent map. Further, we give an extended remark in the appendix on the possibility of an F-crystal structure on the crystalline cohomology of a K3 surface over an algebraically closed field of positive characteristic and show that the naive F-crystal structure fails in being compatible with inner product. }, author = {Srivastava, Tanya K}, issn = {1431-0643}, journal = {Documenta Mathematica}, pages = {1135--1177}, publisher = {EMS Press}, title = {{On derived equivalences of k3 surfaces in positive characteristic}}, doi = {10.25537/dm.2019v24.1135-1177}, volume = {24}, year = {2019}, } @article{72, abstract = {We consider the totally asymmetric simple exclusion process (TASEP) with non-random initial condition having density ρ on ℤ− and λ on ℤ+, and a second class particle initially at the origin. For ρ<λ, there is a shock and the second class particle moves with speed 1−λ−ρ. For large time t, we show that the position of the second class particle fluctuates on a t1/3 scale and determine its limiting law. We also obtain the limiting distribution of the number of steps made by the second class particle until time t.}, author = {Ferrari, Patrick and Ghosal, Promit and Nejjar, Peter}, issn = {0246-0203}, journal = {Annales de l'institut Henri Poincare (B) Probability and Statistics}, number = {3}, pages = {1203--1225}, publisher = {Institute of Mathematical Statistics}, title = {{Limit law of a second class particle in TASEP with non-random initial condition}}, doi = {10.1214/18-AIHP916}, volume = {55}, year = {2019}, } @inproceedings{6646, abstract = {We demonstrate robust retention of valley coherence and its control via polariton pseudospin precession through the optical TE-TM splitting in bilayer WS2 microcavity exciton polaritons at room temperature.}, author = {Khatoniar, Mandeep and Yama, Nicholas and Ghazaryan, Areg and Guddala, Sriram and Ghaemi, Pouyan and Menon, Vinod}, booktitle = {CLEO: Applications and Technology}, isbn = {9781943580576}, location = {San Jose, CA, United States}, publisher = {Optica Publishing Group}, title = {{Room temperature control of valley coherence in bilayer WS2 exciton polaritons}}, doi = {10.1364/cleo_at.2019.jtu2a.52}, year = {2019}, } @inproceedings{7233, abstract = {We demonstrate electro-optic frequency comb generation using a doubly resonant system comprising a whispering gallery mode disk resonator made of lithium niobate mounted inside a three dimensional copper cavity. We observe 180 sidebands centred at 1550 nm.}, author = {Rueda Sanchez, Alfredo R and Sedlmeir, Florian and Leuchs, Gerd and Kumari, Madhuri and Schwefel, Harald G.L.}, booktitle = {Nonlinear Optics, OSA Technical Digest}, isbn = {9781557528209}, location = {Waikoloa Beach, Hawaii (HI), United States}, publisher = {Optica Publishing Group}, title = {{Resonant electro-optic frequency comb generation in lithium niobate disk resonator inside a microwave cavity}}, doi = {10.1364/NLO.2019.NM2A.5}, year = {2019}, } @article{6240, abstract = {For a general class of large non-Hermitian random block matrices X we prove that there are no eigenvalues away from a deterministic set with very high probability. This set is obtained from the Dyson equation of the Hermitization of X as the self-consistent approximation of the pseudospectrum. We demonstrate that the analysis of the matrix Dyson equation from (Probab. Theory Related Fields (2018)) offers a unified treatment of many structured matrix ensembles.}, author = {Alt, Johannes and Erdös, László and Krüger, Torben H and Nemish, Yuriy}, issn = {0246-0203}, journal = {Annales de l'institut Henri Poincare}, number = {2}, pages = {661--696}, publisher = {Institut Henri Poincaré}, title = {{Location of the spectrum of Kronecker random matrices}}, doi = {10.1214/18-AIHP894}, volume = {55}, year = {2019}, } @article{7399, abstract = {Long non-coding (lnc) RNAs are numerous and found throughout the mammalian genome, and many are thought to be involved in the regulation of gene expression. However, the majority remain relatively uncharacterised and of uncertain function making the use of model systems to uncover their mode of action valuable. Imprinted lncRNAs target and recruit epigenetic silencing factors to a cluster of imprinted genes on the same chromosome, making them one of the best characterized lncRNAs for silencing distant genes in cis. In this study we examined silencing of the distant imprinted gene Slc22a3 by the lncRNA Airn in the Igf2r imprinted cluster in mouse. Previously we proposed that imprinted lncRNAs may silence distant imprinted genes by disrupting promoter-enhancer interactions by being transcribed through the enhancer, which we called the enhancer interference hypothesis. Here we tested this hypothesis by first using allele-specific chromosome conformation capture (3C) to detect interactions between the Slc22a3 promoter and the locus of the Airn lncRNA that silences it on the paternal chromosome. In agreement with the model, we found interactions enriched on the maternal allele across the entire Airn gene consistent with multiple enhancer-promoter interactions. Therefore, to test the enhancer interference hypothesis we devised an approach to delete the entire Airn gene. However, the deletion showed that there are no essential enhancers for Slc22a2, Pde10a and Slc22a3 within the Airn gene, strongly indicating that the Airn RNA rather than its transcription is responsible for silencing distant imprinted genes. Furthermore, we found that silent imprinted genes were covered with large blocks of H3K27me3 on the repressed paternal allele. Therefore we propose an alternative hypothesis whereby the chromosome interactions may initially guide the lncRNA to target imprinted promoters and recruit repressive chromatin, and that these interactions are lost once silencing is established.}, author = {Andergassen, Daniel and Muckenhuber, Markus and Bammer, Philipp C. and Kulinski, Tomasz M. and Theussl, Hans-Christian and Shimizu, Takahiko and Penninger, Josef M. and Pauler, Florian and Hudson, Quanah J.}, issn = {1553-7404}, journal = {PLoS Genetics}, number = {7}, publisher = {Public Library of Science}, title = {{The Airn lncRNA does not require any DNA elements within its locus to silence distant imprinted genes}}, doi = {10.1371/journal.pgen.1008268}, volume = {15}, year = {2019}, } @article{7103, abstract = {Origin and functions of intermittent transitions among sleep stages, including short awakenings and arousals, constitute a challenge to the current homeostatic framework for sleep regulation, focusing on factors modulating sleep over large time scales. Here we propose that the complex micro-architecture characterizing the sleep-wake cycle results from an underlying non-equilibrium critical dynamics, bridging collective behaviors across spatio-temporal scales. We investigate θ and δ wave dynamics in control rats and in rats with lesions of sleep-promoting neurons in the parafacial zone. We demonstrate that intermittent bursts in θ and δ rhythms exhibit a complex temporal organization, with long-range power-law correlations and a robust duality of power law (θ-bursts, active phase) and exponential-like (δ-bursts, quiescent phase) duration distributions, typical features of non-equilibrium systems self-organizing at criticality. Crucially, such temporal organization relates to anti-correlated coupling between θ- and δ-bursts, and is independent of the dominant physiologic state and lesions, a solid indication of a basic principle in sleep dynamics.}, author = {Wang, Jilin W. J. L. and Lombardi, Fabrizio and Zhang, Xiyun and Anaclet, Christelle and Ivanov, Plamen Ch.}, issn = {1553-7358}, journal = {PLoS Computational Biology}, number = {11}, publisher = {Public Library of Science}, title = {{Non-equilibrium critical dynamics of bursts in θ and δ rhythms as fundamental characteristic of sleep and wake micro-architecture}}, doi = {10.1371/journal.pcbi.1007268}, volume = {15}, year = {2019}, } @inproceedings{6569, abstract = {Knowledge distillation, i.e. one classifier being trained on the outputs of another classifier, is an empirically very successful technique for knowledge transfer between classifiers. It has even been observed that classifiers learn much faster and more reliably if trained with the outputs of another classifier as soft labels, instead of from ground truth data. So far, however, there is no satisfactory theoretical explanation of this phenomenon. In this work, we provide the first insights into the working mechanisms of distillation by studying the special case of linear and deep linear classifiers. Specifically, we prove a generalization bound that establishes fast convergence of the expected risk of a distillation-trained linear classifier. From the bound and its proof we extract three keyfactors that determine the success of distillation: data geometry – geometric properties of the datadistribution, in particular class separation, has an immediate influence on the convergence speed of the risk; optimization bias– gradient descentoptimization finds a very favorable minimum of the distillation objective; and strong monotonicity– the expected risk of the student classifier always decreases when the size of the training set grows.}, author = {Bui Thi Mai, Phuong and Lampert, Christoph}, booktitle = {Proceedings of the 36th International Conference on Machine Learning}, location = {Long Beach, CA, United States}, pages = {5142--5151}, publisher = {ML Research Press}, title = {{Towards understanding knowledge distillation}}, volume = {97}, year = {2019}, } @inproceedings{6590, abstract = {Modern machine learning methods often require more data for training than a single expert can provide. Therefore, it has become a standard procedure to collect data from external sources, e.g. via crowdsourcing. Unfortunately, the quality of these sources is not always guaranteed. As additional complications, the data might be stored in a distributed way, or might even have to remain private. In this work, we address the question of how to learn robustly in such scenarios. Studying the problem through the lens of statistical learning theory, we derive a procedure that allows for learning from all available sources, yet automatically suppresses irrelevant or corrupted data. We show by extensive experiments that our method provides significant improvements over alternative approaches from robust statistics and distributed optimization. }, author = {Konstantinov, Nikola H and Lampert, Christoph}, booktitle = {Proceedings of the 36th International Conference on Machine Learning}, location = {Long Beach, CA, USA}, pages = {3488--3498}, publisher = {ML Research Press}, title = {{Robust learning from untrusted sources}}, volume = {97}, year = {2019}, } @article{6999, abstract = {Plasmodesmata (PD) are plant-specific membrane-lined channels that create cytoplasmic and membrane continuities between adjacent cells, thereby facilitating cell–cell communication and virus movement. Plant cells have evolved diverse mechanisms to regulate PD plasticity in response to numerous environmental stimuli. In particular, during defense against plant pathogens, the defense hormone, salicylic acid (SA), plays a crucial role in the regulation of PD permeability in a callose-dependent manner. Here, we uncover a mechanism by which plants restrict the spreading of virus and PD cargoes using SA signaling by increasing lipid order and closure of PD. We showed that exogenous SA application triggered the compartmentalization of lipid raft nanodomains through a modulation of the lipid raft-regulatory protein, Remorin (REM). Genetic studies, superresolution imaging, and transmission electron microscopy observation together demonstrated that Arabidopsis REM1.2 and REM1.3 are crucial for plasma membrane nanodomain assembly to control PD aperture and functionality. In addition, we also found that a 14-3-3 epsilon protein modulates REM clustering and membrane nanodomain compartmentalization through its direct interaction with REM proteins. This study unveils a molecular mechanism by which the key plant defense hormone, SA, triggers membrane lipid nanodomain reorganization, thereby regulating PD closure to impede virus spreading.}, author = {Huang, D and Sun, Y and Ma, Z and Ke, M and Cui, Y and Chen, Z and Chen, C and Ji, C and Tran, TM and Yang, L and Lam, SM and Han, Y and Shu, G and Friml, Jiří and Miao, Y and Jiang, L and Chen, X}, issn = {1091-6490}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, number = {42}, pages = {21274--21284}, publisher = {Proceedings of the National Academy of Sciences}, title = {{Salicylic acid-mediated plasmodesmal closure via Remorin-dependent lipid organization}}, doi = {10.1073/pnas.1911892116}, volume = {116}, year = {2019}, }