TY - JOUR AB - Plants can regenerate their bodies via de novo establishment of shoot apical meristems (SAMs) from pluripotent callus. Only a small fraction of callus cells is eventually specified into SAMs but the molecular mechanisms underlying fate specification remain obscure. The expression of WUSCHEL (WUS) is an early hallmark of SAM fate acquisition. Here, we show that a WUS paralog, WUSCHEL-RELATED HOMEOBOX 13 (WOX13), negatively regulates SAM formation from callus in Arabidopsis thaliana. WOX13 promotes non-meristematic cell fate via transcriptional repression of WUS and other SAM regulators and activation of cell wall modifiers. Our Quartz-Seq2–based single cell transcriptome revealed that WOX13 plays key roles in determining cellular identity of callus cell population. We propose that reciprocal inhibition between WUS and WOX13 mediates critical cell fate determination in pluripotent cell population, which has a major impact on regeneration efficiency. AU - Ogura, Nao AU - Sasagawa, Yohei AU - Ito, Tasuku AU - Tameshige, Toshiaki AU - Kawai, Satomi AU - Sano, Masaki AU - Doll, Yuki AU - Iwase, Akira AU - Kawamura, Ayako AU - Suzuki, Takamasa AU - Nikaido, Itoshi AU - Sugimoto, Keiko AU - Ikeuchi, Momoko ID - 13259 IS - 27 JF - Science Advances TI - WUSCHEL-RELATED HOMEOBOX 13 suppresses de novo shoot regeneration via cell fate control of pluripotent callus VL - 9 ER - TY - JOUR AB - Conflicts and natural disasters affect entire populations of the countries involved and, in addition to the thousands of lives destroyed, have a substantial negative impact on the scientific advances these countries provide. The unprovoked invasion of Ukraine by Russia, the devastating earthquake in Turkey and Syria, and the ongoing conflicts in the Middle East are just a few examples. Millions of people have been killed or displaced, their futures uncertain. These events have resulted in extensive infrastructure collapse, with loss of electricity, transportation, and access to services. Schools, universities, and research centers have been destroyed along with decades’ worth of data, samples, and findings. Scholars in disaster areas face short- and long-term problems in terms of what they can accomplish now for obtaining grants and for employment in the long run. In our interconnected world, conflicts and disasters are no longer a local problem but have wide-ranging impacts on the entire world, both now and in the future. Here, we focus on the current and ongoing impact of war on the scientific community within Ukraine and from this draw lessons that can be applied to all affected countries where scientists at risk are facing hardship. We present and classify examples of effective and feasible mechanisms used to support researchers in countries facing hardship and discuss how these can be implemented with help from the international scientific community and what more is desperately needed. Reaching out, providing accessible training opportunities, and developing collaborations should increase inclusion and connectivity, support scientific advancements within affected communities, and expedite postwar and disaster recovery. AU - Wolfsberger, Walter AU - Chhugani, Karishma AU - Shchubelka, Khrystyna AU - Frolova, Alina AU - Salyha, Yuriy AU - Zlenko, Oksana AU - Arych, Mykhailo AU - Dziuba, Dmytro AU - Parkhomenko, Andrii AU - Smolanka, Volodymyr AU - Gümüş, Zeynep H. AU - Sezgin, Efe AU - Diaz-Lameiro, Alondra AU - Toth, Viktor R. AU - Maci, Megi AU - Bortz, Eric AU - Kondrashov, Fyodor AU - Morton, Patricia M. AU - Łabaj, Paweł P. AU - Romero, Veronika AU - Hlávka, Jakub AU - Mangul, Serghei AU - Oleksyk, Taras K. ID - 13976 JF - GigaScience TI - Scientists without borders: Lessons from Ukraine VL - 12 ER - TY - JOUR AB - We construct families of log K3 surfaces and study the arithmetic of their members. We use this to produce explicit surfaces with an order 5 Brauer–Manin obstruction to the integral Hasse principle. AU - Lyczak, Julian ID - 13973 IS - 2 JF - Annales de l'Institut Fourier SN - 0373-0956 TI - Order 5 Brauer–Manin obstructions to the integral Hasse principle on log K3 surfaces VL - 73 ER - TY - JOUR AB - The Tverberg theorem is one of the cornerstones of discrete geometry. It states that, given a set X of at least (d+1)(r−1)+1 points in Rd, one can find a partition X=X1∪⋯∪Xr of X, such that the convex hulls of the Xi, i=1,…,r, all share a common point. In this paper, we prove a trengthening of this theorem that guarantees a partition which, in addition to the above, has the property that the boundaries of full-dimensional convex hulls have pairwise nonempty intersections. Possible generalizations and algorithmic aspects are also discussed. As a concrete application, we show that any n points in the plane in general position span ⌊n/3⌋ vertex-disjoint triangles that are pairwise crossing, meaning that their boundaries have pairwise nonempty intersections; this number is clearly best possible. A previous result of Álvarez-Rebollar et al. guarantees ⌊n/6⌋pairwise crossing triangles. Our result generalizes to a result about simplices in Rd, d≥2. AU - Fulek, Radoslav AU - Gärtner, Bernd AU - Kupavskii, Andrey AU - Valtr, Pavel AU - Wagner, Uli ID - 13974 JF - Discrete and Computational Geometry SN - 0179-5376 TI - The crossing Tverberg theorem ER - TY - JOUR AB - We consider the spectrum of random Laplacian matrices of the form Ln=An−Dn where An is a real symmetric random matrix and Dn is a diagonal matrix whose entries are equal to the corresponding row sums of An. If An is a Wigner matrix with entries in the domain of attraction of a Gaussian distribution, the empirical spectral measure of Ln is known to converge to the free convolution of a semicircle distribution and a standard real Gaussian distribution. We consider real symmetric random matrices An with independent entries (up to symmetry) whose row sums converge to a purely non-Gaussian infinitely divisible distribution, which fall into the class of Lévy–Khintchine random matrices first introduced by Jung [Trans Am Math Soc, 370, (2018)]. Our main result shows that the empirical spectral measure of Ln converges almost surely to a deterministic limit. A key step in the proof is to use the purely non-Gaussian nature of the row sums to build a random operator to which Ln converges in an appropriate sense. This operator leads to a recursive distributional equation uniquely describing the Stieltjes transform of the limiting empirical spectral measure. AU - Campbell, Andrew J AU - O’Rourke, Sean ID - 13975 JF - Journal of Theoretical Probability SN - 0894-9840 TI - Spectrum of Lévy–Khintchine random laplacian matrices ER - TY - JOUR AB - The magnetotropic susceptibility is the thermodynamic coefficient associated with the rotational anisotropy of the free energy in an external magnetic field and is closely related to the magnetic susceptibility. It emerges naturally in frequency-shift measurements of oscillating mechanical cantilevers, which are becoming an increasingly important tool in the quantitative study of the thermodynamics of modern condensed-matter systems. Here we discuss the basic properties of the magnetotropic susceptibility as they relate to the experimental aspects of frequency-shift measurements, as well as to the interpretation of those experiments in terms of the intrinsic properties of the system under study. AU - Shekhter, A. AU - Mcdonald, R. D. AU - Ramshaw, B. J. AU - Modic, Kimberly A ID - 13257 IS - 3 JF - Physical Review B SN - 2469-9950 TI - Magnetotropic susceptibility VL - 108 ER - TY - JOUR AB - This Special Collection is dedicated to the field of photocatalytic synthesis and contains a diverse selection of original research contributions. It includes studies on catalyst development, mechanistic investigations, method development and the use of enabling technologies, illustrating the many facets of state-of-the-art research in photocatalytic synthesis. Further, emerging topics are surveyed and discussed in three reviews and a concept article. AU - Næsborg, Line AU - Pieber, Bartholomäus AU - Wenger, Oliver S. ID - 13972 JF - ChemCatChem SN - 1867-3880 TI - Special Collection: Photocatalytic synthesis ER - TY - JOUR AB - The use of multimodal readout mechanisms next to label-free real-time monitoring of biomolecular interactions can provide valuable insight into surface-based reaction mechanisms. To this end, the combination of an electrolyte-gated field-effect transistor (EG-FET) with a fiber optic-coupled surface plasmon resonance (FO-SPR) probe serving as gate electrode has been investigated to deconvolute surface mass and charge density variations associated to surface reactions. However, applying an electrochemical potential on such gold-coated FO-SPR gate electrodes can induce gradual morphological changes of the thin gold film, leading to an irreversible blue-shift of the SPR wavelength and a substantial signal drift. We show that mild annealing leads to optical and electronic signal stabilization (20-fold lower signal drift than as-sputtered fiber optic gates) and improved overall analytical performance characteristics. The thermal treatment prevents morphological changes of the thin gold-film occurring during operation, hence providing reliable and stable data immediately upon gate voltage application. Thus, the readout output of both transducing principles, the optical FO-SPR and electronic EG-FET, stays constant throughout the whole sensing time-window and the long-term effect of thermal treatment is also improved, providing stable signals even after 1 year of storage. Annealing should therefore be considered a necessary modification for applying fiber optic gate electrodes in real-time multimodal investigations of surface reactions at the solid-liquid interface. AU - Hasler, Roger AU - Steger-Polt, Marie Helene AU - Reiner-Rozman, Ciril AU - Fossati, Stefan AU - Lee, Seungho AU - Aspermair, Patrik AU - Kleber, Christoph AU - Ibáñez, Maria AU - Dostalek, Jakub AU - Knoll, Wolfgang ID - 13968 JF - Frontiers in Physics TI - Optical and electronic signal stabilization of plasmonic fiber optic gate electrodes: Towards improved real-time dual-mode biosensing VL - 11 ER - TY - JOUR AB - Long-time and large-data existence of weak solutions for initial- and boundary-value problems concerning three-dimensional flows of incompressible fluids is nowadays available not only for Navier–Stokes fluids but also for various fluid models where the relation between the Cauchy stress tensor and the symmetric part of the velocity gradient is nonlinear. The majority of such studies however concerns models where such a dependence is explicit (the stress is a function of the velocity gradient), which makes the class of studied models unduly restrictive. The same concerns boundary conditions, or more precisely the slipping mechanisms on the boundary, where the no-slip is still the most preferred condition considered in the literature. Our main objective is to develop a robust mathematical theory for unsteady internal flows of implicitly constituted incompressible fluids with implicit relations between the tangential projections of the velocity and the normal traction on the boundary. The theory covers numerous rheological models used in chemistry, biorheology, polymer and food industry as well as in geomechanics. It also includes, as special cases, nonlinear slip as well as stick–slip boundary conditions. Unlike earlier studies, the conditions characterizing admissible classes of constitutive equations are expressed by means of tools of elementary calculus. In addition, a fully constructive proof (approximation scheme) is incorporated. Finally, we focus on the question of uniqueness of such weak solutions. AU - Bulíček, Miroslav AU - Málek, Josef AU - Maringová, Erika ID - 14042 IS - 3 JF - Journal of Mathematical Fluid Mechanics SN - 1422-6928 TI - On unsteady internal flows of incompressible fluids characterized by implicit constitutive equations in the bulk and on the boundary VL - 25 ER - TY - JOUR AB - Tissue morphogenesis and patterning during development involve the segregation of cell types. Segregation is driven by differential tissue surface tensions generated by cell types through controlling cell-cell contact formation by regulating adhesion and actomyosin contractility-based cellular cortical tensions. We use vertebrate tissue cell types and zebrafish germ layer progenitors as in vitro models of 3-dimensional heterotypic segregation and developed a quantitative analysis of their dynamics based on 3D time-lapse microscopy. We show that general inhibition of actomyosin contractility by the Rho kinase inhibitor Y27632 delays segregation. Cell type-specific inhibition of non-muscle myosin2 activity by overexpression of myosin assembly inhibitor S100A4 reduces tissue surface tension, manifested in decreased compaction during aggregation and inverted geometry observed during segregation. The same is observed when we express a constitutively active Rho kinase isoform to ubiquitously keep actomyosin contractility high at cell-cell and cell-medium interfaces and thus overriding the interface-specific regulation of cortical tensions. Tissue surface tension regulation can become an effective tool in tissue engineering. AU - Méhes, Elod AU - Mones, Enys AU - Varga, Máté AU - Zsigmond, Áron AU - Biri-Kovács, Beáta AU - Nyitray, László AU - Barone, Vanessa AU - Krens, Gabriel AU - Heisenberg, Carl-Philipp J AU - Vicsek, Tamás ID - 14041 JF - Communications Biology TI - 3D cell segregation geometry and dynamics are governed by tissue surface tension regulation VL - 6 ER - TY - JOUR AB - Membranes are essential for life. They act as semi-permeable boundaries that define cells and organelles. In addition, their surfaces actively participate in biochemical reaction networks, where they confine proteins, align reaction partners, and directly control enzymatic activities. Membrane-localized reactions shape cellular membranes, define the identity of organelles, compartmentalize biochemical processes, and can even be the source of signaling gradients that originate at the plasma membrane and reach into the cytoplasm and nucleus. The membrane surface is, therefore, an essential platform upon which myriad cellular processes are scaffolded. In this review, we summarize our current understanding of the biophysics and biochemistry of membrane-localized reactions with particular focus on insights derived from reconstituted and cellular systems. We discuss how the interplay of cellular factors results in their self-organization, condensation, assembly, and activity, and the emergent properties derived from them. AU - Leonard, Thomas A. AU - Loose, Martin AU - Martens, Sascha ID - 14039 IS - 15 JF - Developmental Cell SN - 1534-5807 TI - The membrane surface as a platform that organizes cellular and biochemical processes VL - 58 ER - TY - JOUR AB - Robust oxygenic photosynthesis requires a suite of accessory factors to ensure efficient assembly and repair of the oxygen-evolving photosystem two (PSII) complex. The highly conserved Ycf48 assembly factor binds to the newly synthesized D1 reaction center polypeptide and promotes the initial steps of PSII assembly, but its binding site is unclear. Here we use cryo-electron microscopy to determine the structure of a cyanobacterial PSII D1/D2 reaction center assembly complex with Ycf48 attached. Ycf48, a 7-bladed beta propeller, binds to the amino-acid residues of D1 that ultimately ligate the water-oxidising Mn4CaO5 cluster, thereby preventing the premature binding of Mn2+ and Ca2+ ions and protecting the site from damage. Interactions with D2 help explain how Ycf48 promotes assembly of the D1/D2 complex. Overall, our work provides valuable insights into the early stages of PSII assembly and the structural changes that create the binding site for the Mn4CaO5 cluster. AU - Zhao, Ziyu AU - Vercellino, Irene AU - Knoppová, Jana AU - Sobotka, Roman AU - Murray, James W. AU - Nixon, Peter J. AU - Sazanov, Leonid A AU - Komenda, Josef ID - 14040 JF - Nature Communications TI - The Ycf48 accessory factor occupies the site of the oxygen-evolving manganese cluster during photosystem II biogenesis VL - 14 ER - TY - CONF AB - A classic solution technique for Markov decision processes (MDP) and stochastic games (SG) is value iteration (VI). Due to its good practical performance, this approximative approach is typically preferred over exact techniques, even though no practical bounds on the imprecision of the result could be given until recently. As a consequence, even the most used model checkers could return arbitrarily wrong results. Over the past decade, different works derived stopping criteria, indicating when the precision reaches the desired level, for various settings, in particular MDP with reachability, total reward, and mean payoff, and SG with reachability.In this paper, we provide the first stopping criteria for VI on SG with total reward and mean payoff, yielding the first anytime algorithms in these settings. To this end, we provide the solution in two flavours: First through a reduction to the MDP case and second directly on SG. The former is simpler and automatically utilizes any advances on MDP. The latter allows for more local computations, heading towards better practical efficiency.Our solution unifies the previously mentioned approaches for MDP and SG and their underlying ideas. To achieve this, we isolate objective-specific subroutines as well as identify objective-independent concepts. These structural concepts, while surprisingly simple, form the very essence of the unified solution. AU - Kretinsky, Jan AU - Meggendorfer, Tobias AU - Weininger, Maximilian ID - 13967 SN - 1043-6871 T2 - 38th Annual ACM/IEEE Symposium on Logic in Computer Science TI - Stopping criteria for value iteration on stochastic games with quantitative objectives VL - 2023 ER - TY - JOUR AB - Many modes and mechanisms of epigenetic inheritance have been elucidated in eukaryotes. Most of them are relatively short-term, generally not exceeding one or a few organismal generations. However, emerging evidence indicates that one mechanism, cytosine DNA methylation, can mediate epigenetic inheritance over much longer timescales, which are mostly or completely inaccessible in the laboratory. Here we discuss the evidence for, and mechanisms and implications of, such long-term epigenetic inheritance. We argue that compelling evidence supports the long-term epigenetic inheritance of gene body methylation, at least in the model angiosperm Arabidopsis thaliana, and that variation in such methylation can therefore serve as an epigenetic basis for phenotypic variation in natural populations. AU - Hollwey, Elizabeth AU - Briffa, Amy AU - Howard, Martin AU - Zilberman, Daniel ID - 13965 IS - 8 JF - Current Opinion in Genetics and Development SN - 0959-437X TI - Concepts, mechanisms and implications of long-term epigenetic inheritance VL - 81 ER - TY - THES AB - Females and males across species are subject to divergent selective pressures arising from di↵erent reproductive interests and ecological niches. This often translates into a intricate array of sex-specific natural and sexual selection on traits that have a shared genetic basis between both sexes, causing a genetic sexual conflict. The resolution of this conflict mostly relies on the evolution of sex-specific expression of the shared genes, leading to phenotypic sexual dimorphism. Such sex-specific gene expression is thought to evolve via modifications of the genetic networks ultimately linked to sex-determining transcription factors. Although much empirical and theoretical evidence supports this standard picture of the molecular basis of sexual conflict resolution, there still are a few open questions regarding the complex array of selective forces driving phenotypic di↵erentiation between the sexes, as well as the molecular mechanisms underlying sexspecific adaptation. I address some of these open questions in my PhD thesis. First, how do patterns of phenotypic sexual dimorphism vary within populations, as a response to the temporal and spatial changes in sex-specific selective forces? To tackle this question, I analyze the patterns of sex-specific phenotypic variation along three life stages and across populations spanning the whole geographical range of Rumex hastatulus, a wind-pollinated angiosperm, in the first Chapter of the thesis. Second, how do gene expression patterns lead to phenotypic dimorphism, and what are the molecular mechanisms underlying the observed transcriptomic variation? I address this question by examining the sex- and tissue-specific expression variation in newly-generated datasets of sex-specific expression in heads and gonads of Drosophila melanogaster. I additionally used two complementary approaches for the study of the genetic basis of sex di↵erences in gene expression in the second and third Chapters of the thesis. Third, how does intersex correlation, thought to be one of the main aspects constraining the ability for the two sexes to decouple, interact with the evolution of sexual dimorphism? I develop models of sex-specific stabilizing selection, mutation and drift to formalize common intuition regarding the patterns of covariation between intersex correlation and sexual dimorphism in the fourth Chapter of the thesis. Alltogether, the work described in this PhD thesis provides useful insights into the links between genetic, transcriptomic and phenotypic layers of sex-specific variation, and contributes to our general understanding of the dynamics of sexual dimorphism evolution. AU - Puixeu Sala, Gemma ID - 14058 SN - 2663-337X TI - The molecular basis of sexual dimorphism: Experimental and theoretical characterization of phenotypic, transcriptomic and genetic patterns of sex-specific adaptation ER - TY - JOUR AB - The regulatory architecture of gene expression is known to differ substantially between sexes in Drosophila, but most studies performed so far used whole-body data and only single crosses, which may have limited their scope to detect patterns that are robust across tissues and biological replicates. Here, we use allele-specific gene expression of parental and reciprocal hybrid crosses between 6 Drosophila melanogaster inbred lines to quantify cis- and trans-regulatory variation in heads and gonads of both sexes separately across 3 replicate crosses. Our results suggest that female and male heads, as well as ovaries, have a similar regulatory architecture. On the other hand, testes display more and substantially different cis-regulatory effects, suggesting that sex differences in the regulatory architecture that have been previously observed may largely derive from testis-specific effects. We also examine the difference in cis-regulatory variation of genes across different levels of sex bias in gonads and heads. Consistent with the idea that intersex correlations constrain expression and can lead to sexual antagonism, we find more cis variation in unbiased and moderately biased genes in heads. In ovaries, reduced cis variation is observed for male-biased genes, suggesting that cis variants acting on these genes in males do not lead to changes in ovary expression. Finally, we examine the dominance patterns of gene expression and find that sex- and tissue-specific patterns of inheritance as well as trans-regulatory variation are highly variable across biological crosses, although these were performed in highly controlled experimental conditions. This highlights the importance of using various genetic backgrounds to infer generalizable patterns. AU - Puixeu Sala, Gemma AU - Macon, Ariana AU - Vicoso, Beatriz ID - 14077 IS - 8 JF - G3: Genes, Genomes, Genetics KW - Genetics (clinical) KW - Genetics KW - Molecular Biology SN - 2160-1836 TI - Sex-specific estimation of cis and trans regulation of gene expression in heads and gonads of Drosophila melanogaster VL - 13 ER - TY - JOUR AB - Most permissionless blockchains inherently suffer from throughput limitations. Layer-2 systems, such as side-chains or Rollups, have been proposed as a possible strategy to overcome this limitation. Layer-2 systems interact with the main-chain in two ways. First, users can move funds from/to the main-chain to/from the layer-2. Second, layer-2 systems periodically synchronize with the main-chain to keep some form of log of their activity on the main-chain - this log is key for security. Due to this interaction with the main-chain, which is necessary and recurrent, layer-2 systems impose some load on the main-chain. The impact of such load on the main-chain has been, so far, poorly understood. In addition to that, layer-2 approaches typically sacrifice decentralization and security in favor of higher throughput. This paper presents an experimental study that analyzes the current state of Ethereum layer-2 projects. Our goal is to assess the load they impose on Ethereum and to understand their scalability potential in the long-run. Our analysis shows that the impact of any given layer-2 on the main-chain is the result of both technical aspects (how state is logged on the main-chain) and user behavior (how often users decide to transfer funds between the layer-2 and the main-chain). Based on our observations, we infer that without efficient mechanisms that allow users to transfer funds in a secure and fast manner directly from one layer-2 project to another, current layer-2 systems will not be able to scale Ethereum effectively, regardless of their technical solutions. Furthermore, from our results, we conclude that the layer-2 systems that offer similar security guarantees as Ethereum have limited scalability potential, while approaches that offer better performance, sacrifice security and lead to an increase in centralization which runs against the end-goals of permissionless blockchains. AU - Neiheiser, Ray AU - Inacio, Gustavo AU - Rech, Luciana AU - Montez, Carlos AU - Matos, Miguel AU - Rodrigues, Luis ID - 13988 JF - IEEE Access KW - General Engineering KW - General Materials Science KW - General Computer Science KW - Electrical and Electronic Engineering SN - 2169-3536 TI - Practical limitations of Ethereum’s layer-2 VL - 11 ER - TY - DATA AB - Datasets of the publication "Sex-specific estimation of cis and trans regulation of gene expression in heads and gonads of Drosophila melanogaster". AU - Puixeu Sala, Gemma ID - 12933 TI - Data from: Sex-specific estimation of cis and trans regulation of gene expression in heads and gonads of Drosophila melanogaster ER - TY - JOUR AB - We establish effective counting results for lattice points in families of domains in real, complex and quaternionic hyperbolic spaces of any dimension. The domains we focus on are defined as product sets with respect to an Iwasawa decomposition. Several natural diophantine problems can be reduced to counting lattice points in such domains. These include equidistribution of the ratio of the length of the shortest solution (x,y) to the gcd equation bx−ay=1 relative to the length of (a,b), where (a,b) ranges over primitive vectors in a disc whose radius increases, the natural analog of this problem in imaginary quadratic number fields, as well as equidistribution of integral solutions to the diophantine equation defined by an integral Lorentz form in three or more variables. We establish an effective rate of convergence for these equidistribution problems, depending on the size of the spectral gap associated with a suitable lattice subgroup in the isometry group of the relevant hyperbolic space. The main result underlying our discussion amounts to establishing effective joint equidistribution for the horospherical component and the radial component in the Iwasawa decomposition of lattice elements. AU - Horesh, Tal AU - Nevo, Amos ID - 14245 IS - 2 JF - Pacific Journal of Mathematics SN - 0030-8730 TI - Horospherical coordinates of lattice points in hyperbolic spaces: Effective counting and equidistribution VL - 324 ER - TY - JOUR AB - The model of a ring threaded by the Aharonov-Bohm flux underlies our understanding of a coupling between gauge potentials and matter. The typical formulation of the model is based upon a single particle picture, and should be extended when interactions with other particles become relevant. Here, we illustrate such an extension for a particle in an Aharonov-Bohm ring subject to interactions with a weakly interacting Bose gas. We show that the ground state of the system can be described using the Bose-polaron concept—a particle dressed by interactions with a bosonic environment. We connect the energy spectrum to the effective mass of the polaron, and demonstrate how to change currents in the system by tuning boson-particle interactions. Our results suggest the Aharonov-Bohm ring as a platform for studying coherence and few- to many-body crossover of quasi-particles that arise from an impurity immersed in a medium. AU - Brauneis, Fabian AU - Ghazaryan, Areg AU - Hammer, Hans-Werner AU - Volosniev, Artem ID - 14246 JF - Communications Physics KW - General Physics and Astronomy SN - 2399-3650 TI - Emergence of a Bose polaron in a small ring threaded by the Aharonov-Bohm flux VL - 6 ER - TY - JOUR AB - Given a resolution of rational singularities π:X~→X over a field of characteristic zero, we use a Hodge-theoretic argument to prove that the image of the functor Rπ∗:Db(X~)→Db(X) between bounded derived categories of coherent sheaves generates Db(X) as a triangulated category. This gives a weak version of the Bondal–Orlov localization conjecture [BO02], answering a question from [PS21]. The same result is established more generally for proper (not necessarily birational) morphisms π:X~→X , with X~ smooth, satisfying Rπ∗(OX~)=OX . AU - Mauri, Mirko AU - Shinder, Evgeny ID - 14239 JF - Forum of Mathematics, Sigma TI - Homological Bondal-Orlov localization conjecture for rational singularities VL - 11 ER - TY - JOUR AB - For the Fröhlich model of the large polaron, we prove that the ground state energy as a function of the total momentum has a unique global minimum at momentum zero. This implies the non-existence of a ground state of the translation invariant Fröhlich Hamiltonian and thus excludes the possibility of a localization transition at finite coupling. AU - Lampart, Jonas AU - Mitrouskas, David Johannes AU - Mysliwy, Krzysztof ID - 14192 IS - 3 JF - Mathematical Physics, Analysis and Geometry KW - Geometry and Topology KW - Mathematical Physics SN - 1385-0172 TI - On the global minimum of the energy–momentum relation for the polaron VL - 26 ER - TY - JOUR AB - We demonstrate that a sodium dimer, Na2(13Σ+u), residing on the surface of a helium nanodroplet, can be set into rotation by a nonresonant 1.0 ps infrared laser pulse. The time-dependent degree of alignment measured, exhibits a periodic, gradually decreasing structure that deviates qualitatively from that expected for gas-phase dimers. Comparison to alignment dynamics calculated from the time-dependent rotational Schrödinger equation shows that the deviation is due to the alignment dependent interaction between the dimer and the droplet surface. This interaction confines the dimer to the tangential plane of the droplet surface at the point where it resides and is the reason that the observed alignment dynamics is also well described by a 2D quantum rotor model. AU - Kranabetter, Lorenz AU - Kristensen, Henrik H. AU - Ghazaryan, Areg AU - Schouder, Constant A. AU - Chatterley, Adam S. AU - Janssen, Paul AU - Jensen, Frank AU - Zillich, Robert E. AU - Lemeshko, Mikhail AU - Stapelfeldt, Henrik ID - 14238 IS - 5 JF - Physical Review Letters SN - 0031-9007 TI - Nonadiabatic laser-induced alignment dynamics of molecules on a surface VL - 131 ER - TY - JOUR AB - Toscana virus is a major cause of arboviral disease in humans in the Mediterranean basin during summer. However, early virus-host cell interactions and entry mechanisms remain poorly characterized. Investigating iPSC-derived human neurons and cell lines, we found that virus binding to the cell surface was specific, and 50% of bound virions were endocytosed within 10 min. Virions entered Rab5a+ early endosomes and, subsequently, Rab7a+ and LAMP-1+ late endosomal compartments. Penetration required intact late endosomes and occurred within 30 min following internalization. Virus entry relied on vacuolar acidification, with an optimal pH for viral membrane fusion at pH 5.5. The pH threshold increased to 5.8 with longer pre-exposure of virions to the slightly acidic pH in early endosomes. Strikingly, the particles remained infectious after entering late endosomes with a pH below the fusion threshold. Overall, our study establishes Toscana virus as a late-penetrating virus and reveals an atypical use of vacuolar acidity by this virus to enter host cells. AU - Koch, Jana AU - Xin, Qilin AU - Obr, Martin AU - Schäfer, Alicia AU - Rolfs, Nina AU - Anagho, Holda A. AU - Kudulyte, Aiste AU - Woltereck, Lea AU - Kummer, Susann AU - Campos, Joaquin AU - Uckeley, Zina M. AU - Bell-Sakyi, Lesley AU - Kräusslich, Hans Georg AU - Schur, Florian Km AU - Acuna, Claudio AU - Lozach, Pierre Yves ID - 14255 IS - 8 JF - PLoS Pathogens SN - 1553-7366 TI - The phenuivirus Toscana virus makes an atypical use of vacuolar acidity to enter host cells VL - 19 ER - TY - JOUR AB - Lateral roots are typically maintained at non-vertical angles with respect to gravity. These gravitropic setpoint angles are intriguing because their maintenance requires that roots are able to effect growth response both with and against the gravity vector, a phenomenon previously attributed to gravitropism acting against an antigravitropic offset mechanism. Here we show how the components mediating gravitropism in the vertical primary root—PINs and phosphatases acting upon them—are reconfigured in their regulation such that lateral root growth at a range of angles can be maintained. We show that the ability of Arabidopsis lateral roots to bend both downward and upward requires the generation of auxin asymmetries and is driven by angle-dependent variation in downward gravitropic auxin flux acting against angle-independent upward, antigravitropic flux. Further, we demonstrate a symmetry in auxin distribution in lateral roots at gravitropic setpoint angle that can be traced back to a net, balanced polarization of PIN3 and PIN7 auxin transporters in the columella. These auxin fluxes are shifted by altering PIN protein phosphoregulation in the columella, either by introducing PIN3 phosphovariant versions or via manipulation of levels of the phosphatase subunit PP2A/RCN1. Finally, we show that auxin, in addition to driving lateral root directional growth, acts within the lateral root columella to induce more vertical growth by increasing RCN1 levels, causing a downward shift in PIN3 localization, thereby diminishing the magnitude of the upward, antigravitropic auxin flux. AU - Roychoudhry, S AU - Sageman-Furnas, K AU - Wolverton, C AU - Grones, Peter AU - Tan, Shutang AU - Molnar, Gergely AU - De Angelis, M AU - Goodman, HL AU - Capstaff, N AU - JPB, Lloyd AU - Mullen, J AU - Hangarter, R AU - Friml, Jiří AU - Kepinski, S ID - 14339 JF - Nature Plants SN - 2055-0278 TI - Antigravitropic PIN polarization maintains non-vertical growth in lateral roots VL - 9 ER - TY - JOUR AB - Mitochondrial networks remodel their connectivity, content, and subcellular localization to support optimized energy production in conditions of increased environmental or cellular stress. Microglia rely on mitochondria to respond to these stressors, however our knowledge about mitochondrial networks and their adaptations in microglia in vivo is limited. Here, we generate a mouse model that selectively labels mitochondria in microglia. We identify that mitochondrial networks are more fragmented with increased content and perinuclear localization in vitro vs. in vivo. Mitochondrial networks adapt similarly in microglia closest to the injury site after optic nerve crush. Preventing microglial UCP2 increase after injury by selective knockout induces cellular stress. This results in mitochondrial hyperfusion in male microglia, a phenotype absent in females due to circulating estrogens. Our results establish the foundation for mitochondrial network analysis of microglia in vivo, emphasizing the importance of mitochondrial-based sex effects of microglia in other pathologies. AU - Maes, Margaret E AU - Colombo, Gloria AU - Schoot Uiterkamp, Florianne E AU - Sternberg, Felix AU - Venturino, Alessandro AU - Pohl, Elena E. AU - Siegert, Sandra ID - 14363 IS - 10 JF - iScience TI - Mitochondrial network adaptations of microglia reveal sex-specific stress response after injury and UCP2 knockout VL - 26 ER - TY - JOUR AB - The total energy of an eigenstate in a composite quantum system tends to be distributed equally among its constituents. We identify the quantum fluctuation around this equipartition principle in the simplest disordered quantum system consisting of linear combinations of Wigner matrices. As our main ingredient, we prove the Eigenstate Thermalisation Hypothesis and Gaussian fluctuation for general quadratic forms of the bulk eigenvectors of Wigner matrices with an arbitrary deformation. AU - Cipolloni, Giorgio AU - Erdös, László AU - Henheik, Sven Joscha AU - Kolupaiev, Oleksii ID - 14343 JF - Forum of Mathematics, Sigma TI - Gaussian fluctuations in the equipartition principle for Wigner matrices VL - 11 ER - TY - JOUR AB - We introduce extension-based proofs, a class of impossibility proofs that includes valency arguments. They are modelled as an interaction between a prover and a protocol. Using proofs based on combinatorial topology, it has been shown that it is impossible to deterministically solve -set agreement among processes or approximate agreement on a cycle of length 4 among processes in a wait-free manner in asynchronous models where processes communicate using objects that can be constructed from shared registers. However, it was unknown whether proofs based on simpler techniques were possible. We show that these impossibility results cannot be obtained by extension-based proofs in the iterated snapshot model and, hence, extension-based proofs are limited in power. AU - Alistarh, Dan-Adrian AU - Aspnes, James AU - Ellen, Faith AU - Gelashvili, Rati AU - Zhu, Leqi ID - 14364 IS - 4 JF - SIAM Journal on Computing SN - 0097-5397 TI - Why extension-based proofs fail VL - 52 ER - TY - JOUR AB - For a locally finite set in R2, the order-k Brillouin tessellations form an infinite sequence of convex face-to-face tilings of the plane. If the set is coarsely dense and generic, then the corresponding infinite sequences of minimum and maximum angles are both monotonic in k. As an example, a stationary Poisson point process in R2 is locally finite, coarsely dense, and generic with probability one. For such a set, the distributions of angles in the Voronoi tessellations, Delaunay mosaics, and Brillouin tessellations are independent of the order and can be derived from the formula for angles in order-1 Delaunay mosaics given by Miles (Math. Biosci. 6, 85–127 (1970)). AU - Edelsbrunner, Herbert AU - Garber, Alexey AU - Ghafari, Mohadese AU - Heiss, Teresa AU - Saghafian, Morteza ID - 14345 JF - Discrete and Computational Geometry SN - 0179-5376 TI - On angles in higher order Brillouin tessellations and related tilings in the plane ER - TY - JOUR AB - Branching morphogenesis is a ubiquitous process that gives rise to high exchange surfaces in the vasculature and epithelial organs. Lymphatic capillaries form branched networks, which play a key role in the circulation of tissue fluid and immune cells. Although mouse models and correlative patient data indicate that the lymphatic capillary density directly correlates with functional output, i.e., tissue fluid drainage and trafficking efficiency of dendritic cells, the mechanisms ensuring efficient tissue coverage remain poorly understood. Here, we use the mouse ear pinna lymphatic vessel network as a model system and combine lineage-tracing, genetic perturbations, whole-organ reconstructions and theoretical modeling to show that the dermal lymphatic capillaries tile space in an optimal, space-filling manner. This coverage is achieved by two complementary mechanisms: initial tissue invasion provides a non-optimal global scaffold via self-organized branching morphogenesis, while VEGF-C dependent side-branching from existing capillaries rapidly optimizes local coverage by directionally targeting low-density regions. With these two ingredients, we show that a minimal biophysical model can reproduce quantitatively whole-network reconstructions, across development and perturbations. Our results show that lymphatic capillary networks can exploit local self-organizing mechanisms to achieve tissue-scale optimization. AU - Ucar, Mehmet C AU - Hannezo, Edouard B AU - Tiilikainen, Emmi AU - Liaqat, Inam AU - Jakobsson, Emma AU - Nurmi, Harri AU - Vaahtomeri, Kari ID - 14378 JF - Nature Communications TI - Self-organized and directed branching results in optimal coverage in developing dermal lymphatic networks VL - 14 ER - TY - JOUR AB - Whether one considers swarming insects, flocking birds, or bacterial colonies, collective motion arises from the coordination of individuals and entails the adjustment of their respective velocities. In particular, in close confinements, such as those encountered by dense cell populations during development or regeneration, collective migration can only arise coordinately. Yet, how individuals unify their velocities is often not understood. Focusing on a finite number of cells in circular confinements, we identify waves of polymerizing actin that function as a pacemaker governing the speed of individual cells. We show that the onset of collective motion coincides with the synchronization of the wave nucleation frequencies across the population. Employing a simpler and more readily accessible mechanical model system of active spheres, we identify the synchronization of the individuals’ internal oscillators as one of the essential requirements to reach the corresponding collective state. The mechanical ‘toy’ experiment illustrates that the global synchronous state is achieved by nearest neighbor coupling. We suggest by analogy that local coupling and the synchronization of actin waves are essential for the emergent, self-organized motion of cell collectives. AU - Riedl, Michael AU - Mayer, Isabelle D AU - Merrin, Jack AU - Sixt, Michael K AU - Hof, Björn ID - 14361 JF - Nature Communications TI - Synchronization in collectively moving inanimate and living active matter VL - 14 ER - TY - JOUR AB - Only recently has it been possible to construct a self-adjoint Hamiltonian that involves the creation of Dirac particles at a point source in 3d space. Its definition makes use of an interior-boundary condition. Here, we develop for this Hamiltonian a corresponding theory of the Bohmian configuration. That is, we (non-rigorously) construct a Markov jump process $(Q_t)_{t\in\mathbb{R}}$ in the configuration space of a variable number of particles that is $|\psi_t|^2$-distributed at every time t and follows Bohmian trajectories between the jumps. The jumps correspond to particle creation or annihilation events and occur either to or from a configuration with a particle located at the source. The process is the natural analog of Bell's jump process, and a central piece in its construction is the determination of the rate of particle creation. The construction requires an analysis of the asymptotic behavior of the Bohmian trajectories near the source. We find that the particle reaches the source with radial speed 0, but orbits around the source infinitely many times in finite time before absorption (or after emission). AU - Henheik, Sven Joscha AU - Tumulka, Roderich ID - 14421 IS - 44 JF - Journal of Physics A: Mathematical and Theoretical SN - 1751-8113 TI - Creation rate of Dirac particles at a point source VL - 56 ER - TY - JOUR AB - We consider the problem of computing the maximal probability of satisfying an -regular specification for stochastic, continuous-state, nonlinear systems evolving in discrete time. The problem reduces, after automata-theoretic constructions, to finding the maximal probability of satisfying a parity condition on a (possibly hybrid) state space. While characterizing the exact satisfaction probability is open, we show that a lower bound on this probability can be obtained by (I) computing an under-approximation of the qualitative winning region, i.e., states from which the parity condition can be enforced almost surely, and (II) computing the maximal probability of reaching this qualitative winning region. The heart of our approach is a technique to symbolically compute the under-approximation of the qualitative winning region in step (I) via a finite-state abstraction of the original system as a -player parity game. Our abstraction procedure uses only the support of the probabilistic evolution; it does not use precise numerical transition probabilities. We prove that the winning set in the abstract -player game induces an under-approximation of the qualitative winning region in the original synthesis problem, along with a policy to solve it. By combining these contributions with (a) a symbolic fixpoint algorithm to solve -player games and (b) existing techniques for reachability policy synthesis in stochastic nonlinear systems, we get an abstraction-based algorithm for finding a lower bound on the maximal satisfaction probability. We have implemented the abstraction-based algorithm in Mascot-SDS, where we combined the outlined abstraction step with our tool Genie (Majumdar et al., 2023) that solves -player parity games (through a reduction to Rabin games) more efficiently than existing algorithms. We evaluated our implementation on the nonlinear model of a perturbed bistable switch from the literature. We show empirically that the lower bound on the winning region computed by our approach is precise, by comparing against an over-approximation of the qualitative winning region. Moreover, our implementation outperforms a recently proposed tool for solving this problem by a large margin. AU - Majumdar, Rupak AU - Mallik, Kaushik AU - Schmuck, Anne Kathrin AU - Soudjani, Sadegh ID - 14400 JF - Nonlinear Analysis: Hybrid Systems SN - 1751-570X TI - Symbolic control for stochastic systems via finite parity games VL - 51 ER - TY - JOUR AB - Water adsorption and dissociation processes on pristine low-index TiO2 interfaces are important but poorly understood outside the well-studied anatase (101) and rutile (110). To understand these, we construct three sets of machine learning potentials that are simultaneously applicable to various TiO2 surfaces, based on three density-functional-theory approximations. Here we show the water dissociation free energies on seven pristine TiO2 surfaces, and predict that anatase (100), anatase (110), rutile (001), and rutile (011) favor water dissociation, anatase (101) and rutile (100) have mostly molecular adsorption, while the simulations of rutile (110) sensitively depend on the slab thickness and molecular adsorption is preferred with thick slabs. Moreover, using an automated algorithm, we reveal that these surfaces follow different types of atomistic mechanisms for proton transfer and water dissociation: one-step, two-step, or both. These mechanisms can be rationalized based on the arrangements of water molecules on the different surfaces. Our finding thus demonstrates that the different pristine TiO2 surfaces react with water in distinct ways, and cannot be represented using just the low-energy anatase (101) and rutile (110) surfaces. AU - Zeng, Zezhu AU - Wodaczek, Felix AU - Liu, Keyang AU - Stein, Frederick AU - Hutter, Jürg AU - Chen, Ji AU - Cheng, Bingqing ID - 14425 JF - Nature Communications TI - Mechanistic insight on water dissociation on pristine low-index TiO2 surfaces from machine learning molecular dynamics simulations VL - 14 ER - TY - JOUR AB - Squall lines are substantially influenced by the interaction of low-level shear with cold pools associated with convective downdrafts. Beyond an optimal shear amplitude, squall lines tend to orient themselves at an angle with respect to the low-level shear. While the mechanisms behind squall line orientation seem to be increasingly well understood, uncertainties remain on the implications of this orientation. Roca and Fiolleau (2020, https://doi.org/10.1038/s43247-020-00015-4) show that long lived mesoscale convective systems, including squall lines, are disproportionately involved in rainfall extremes in the tropics. This article investigates the influence of the interaction between low-level shear and squall line outflow on squall line generated precipitation extrema in the tropics. Using a cloud resolving model, simulated squall lines in radiative convective equilibrium amid a shear-dominated regime (super optimal), a balanced regime (optimal), and an outflow dominated regime (suboptimal). Our results show that precipitation extremes in squall lines are 40% more intense in the case of optimal shear and remain 30% superior in the superoptimal regime relative to a disorganized case. With a theoretical scaling of precipitation extremes (C. Muller & Takayabu, 2020, https://doi.org/10.1088/1748-9326/ab7130), we show that the condensation rates control the amplification of precipitation extremes in tropical squall lines, mainly due to its change in vertical mass flux (dynamic component). The reduction of dilution by entrainment explains half of this change, consistent with Mulholland et al. (2021, https://doi.org/10.1175/jas-d-20-0299.1). The other half is explained by increased cloud-base velocity intensity in optimal and superoptimal squall lines. AU - Abramian, Sophie AU - Muller, Caroline J AU - Risi, Camille ID - 14453 IS - 10 JF - Journal of Advances in Modeling Earth Systems TI - Extreme precipitation in tropical squall lines VL - 15 ER - TY - JOUR AB - Inversions are thought to play a key role in adaptation and speciation, suppressing recombination between diverging populations. Genes influencing adaptive traits cluster in inversions, and changes in inversion frequencies are associated with environmental differences. However, in many organisms, it is unclear if inversions are geographically and taxonomically widespread. The intertidal snail, Littorina saxatilis, is one such example. Strong associations between putative polymorphic inversions and phenotypic differences have been demonstrated between two ecotypes of L. saxatilis in Sweden and inferred elsewhere, but no direct evidence for inversion polymorphism currently exists across the species range. Using whole genome data from 107 snails, most inversion polymorphisms were found to be widespread across the species range. The frequencies of some inversion arrangements were significantly different among ecotypes, suggesting a parallel adaptive role. Many inversions were also polymorphic in the sister species, L. arcana, hinting at an ancient origin. AU - Reeve, James AU - Butlin, Roger K. AU - Koch, Eva L. AU - Stankowski, Sean AU - Faria, Rui ID - 14463 JF - Molecular Ecology SN - 0962-1083 TI - Chromosomal inversion polymorphisms are widespread across the species ranges of rough periwinkles (Littorina saxatilis and L. arcana) ER - TY - JOUR AU - Narzisi, Antonio AU - Halladay, Alycia AU - Masi, Gabriele AU - Novarino, Gaia AU - Lord, Catherine ID - 14455 JF - Frontiers in Psychiatry TI - Tempering expectations: Considerations on the current state of stem cells therapy for autism treatment VL - 14 ER - TY - JOUR AB - In the paper, we establish Squash Rigidity Theorem—the dynamical spectral rigidity for piecewise analytic Bunimovich squash-type stadia whose convex arcs are homothetic. We also establish Stadium Rigidity Theorem—the dynamical spectral rigidity for piecewise analytic Bunimovich stadia whose flat boundaries are a priori fixed. In addition, for smooth Bunimovich squash-type stadia we compute the Lyapunov exponents along the maximal period two orbit, as well as the value of the Peierls’ Barrier function from the maximal marked length spectrum associated to the rotation number 2n/4n+1. AU - Chen, Jianyu AU - Kaloshin, Vadim AU - Zhang, Hong Kun ID - 14427 JF - Communications in Mathematical Physics SN - 0010-3616 TI - Length spectrum rigidity for piecewise analytic Bunimovich billiards ER - TY - JOUR AB - Given a triangle Δ, we study the problem of determining the smallest enclosing and largest embedded isosceles triangles of Δ with respect to area and perimeter. This problem was initially posed by Nandakumar [17, 22] and was first studied by Kiss, Pach, and Somlai [13], who showed that if Δ′ is the smallest area isosceles triangle containing Δ, then Δ′ and Δ share a side and an angle. In the present paper, we prove that for any triangle Δ, every maximum area isosceles triangle embedded in Δ and every maximum perimeter isosceles triangle embedded in Δ shares a side and an angle with Δ. Somewhat surprisingly, the case of minimum perimeter enclosing triangles is different: there are infinite families of triangles Δ whose minimum perimeter isosceles containers do not share a side and an angle with Δ. AU - Ambrus, Áron AU - Csikós, Mónika AU - Kiss, Gergely AU - Pach, János AU - Somlai, Gábor ID - 14464 IS - 7 JF - International Journal of Foundations of Computer Science SN - 0129-0541 TI - Optimal embedded and enclosing isosceles triangles VL - 34 ER - TY - JOUR AB - The rapid development of machine learning (ML) techniques has opened up the data-dense field of microbiome research for novel therapeutic, diagnostic, and prognostic applications targeting a wide range of disorders, which could substantially improve healthcare practices in the era of precision medicine. However, several challenges must be addressed to exploit the benefits of ML in this field fully. In particular, there is a need to establish “gold standard” protocols for conducting ML analysis experiments and improve interactions between microbiome researchers and ML experts. The Machine Learning Techniques in Human Microbiome Studies (ML4Microbiome) COST Action CA18131 is a European network established in 2019 to promote collaboration between discovery-oriented microbiome researchers and data-driven ML experts to optimize and standardize ML approaches for microbiome analysis. This perspective paper presents the key achievements of ML4Microbiome, which include identifying predictive and discriminatory ‘omics’ features, improving repeatability and comparability, developing automation procedures, and defining priority areas for the novel development of ML methods targeting the microbiome. The insights gained from ML4Microbiome will help to maximize the potential of ML in microbiome research and pave the way for new and improved healthcare practices. AU - D’Elia, Domenica AU - Truu, Jaak AU - Lahti, Leo AU - Berland, Magali AU - Papoutsoglou, Georgios AU - Ceci, Michelangelo AU - Zomer, Aldert AU - Lopes, Marta B. AU - Ibrahimi, Eliana AU - Gruca, Aleksandra AU - Nechyporenko, Alina AU - Frohme, Marcus AU - Klammsteiner, Thomas AU - Pau, Enrique Carrillo De Santa AU - Marcos-Zambrano, Laura Judith AU - Hron, Karel AU - Pio, Gianvito AU - Simeon, Andrea AU - Suharoschi, Ramona AU - Moreno-Indias, Isabel AU - Temko, Andriy AU - Nedyalkova, Miroslava AU - Apostol, Elena Simona AU - Truică, Ciprian Octavian AU - Shigdel, Rajesh AU - Telalović, Jasminka Hasić AU - Bongcam-Rudloff, Erik AU - Przymus, Piotr AU - Jordamović, Naida Babić AU - Falquet, Laurent AU - Tarazona, Sonia AU - Sampri, Alexia AU - Isola, Gaetano AU - Pérez-Serrano, David AU - Trajkovik, Vladimir AU - Klucar, Lubos AU - Loncar-Turukalo, Tatjana AU - Havulinna, Aki S. AU - Jansen, Christian AU - Bertelsen, Randi J. AU - Claesson, Marcus Joakim ID - 14449 JF - Frontiers in Microbiology TI - Advancing microbiome research with machine learning: Key findings from the ML4Microbiome COST action VL - 14 ER - TY - JOUR AB - The quantum approximate optimization algorithm (QAOA) is a variational quantum algorithm, where a quantum computer implements a variational ansatz consisting of p layers of alternating unitary operators and a classical computer is used to optimize the variational parameters. For a random initialization, the optimization typically leads to local minima with poor performance, motivating the search for initialization strategies of QAOA variational parameters. Although numerous heuristic initializations exist, an analytical understanding and performance guarantees for large p remain evasive.We introduce a greedy initialization of QAOA which guarantees improving performance with an increasing number of layers. Our main result is an analytic construction of 2p + 1 transition states—saddle points with a unique negative curvature direction—for QAOA with p + 1 layers that use the local minimum of QAOA with p layers. Transition states connect to new local minima, which are guaranteed to lower the energy compared to the minimum found for p layers. We use the GREEDY procedure to navigate the exponentially increasing with p number of local minima resulting from the recursive application of our analytic construction. The performance of the GREEDY procedure matches available initialization strategies while providing a guarantee for the minimal energy to decrease with an increasing number of layers p. AU - Sack, Stefan AU - Medina Ramos, Raimel A AU - Kueng, Richard AU - Serbyn, Maksym ID - 13125 IS - 6 JF - Physical Review A SN - 2469-9926 TI - Recursive greedy initialization of the quantum approximate optimization algorithm with guaranteed improvement VL - 107 ER - TY - JOUR AB - We prove the following quantitative Borsuk–Ulam-type result (an equivariant analogue of Gromov’s Topological Overlap Theorem): Let X be a free ℤ/2-complex of dimension d with coboundary expansion at least ηk in dimension 0 ≤ k < d. Then for every equivariant map F: X →ℤ/2 ℝd, the fraction of d-simplices σ of X with 0 ∈ F (σ) is at least 2−d Π d−1k=0ηk. As an application, we show that for every sufficiently thick d-dimensional spherical building Y and every map f: Y → ℝ2d, we have f(σ) ∩ f(τ) ≠ ∅ for a constant fraction μd > 0 of pairs {σ, τ} of d-simplices of Y. In particular, such complexes are non-embeddable into ℝ2d, which proves a conjecture of Tancer and Vorwerk for sufficiently thick spherical buildings. We complement these results by upper bounds on the coboundary expansion of two families of simplicial complexes; this indicates some limitations to the bounds one can obtain by straighforward applications of the quantitative Borsuk–Ulam theorem. Specifically, we prove • an upper bound of (d + 1)/2d on the normalized (d − 1)-th coboundary expansion constant of complete (d + 1)-partite d-dimensional complexes (under a mild divisibility assumption on the sizes of the parts); and • an upper bound of (d + 1)/2d + ε on the normalized (d − 1)-th coboundary expansion of the d-dimensional spherical building associated with GLd+2(Fq) for any ε > 0 and sufficiently large q. This disproves, in a rather strong sense, a conjecture of Lubotzky, Meshulam and Mozes. AU - Wagner, Uli AU - Wild, Pascal ID - 14445 IS - 2 JF - Israel Journal of Mathematics SN - 0021-2172 TI - Coboundary expansion, equivariant overlap, and crossing numbers of simplicial complexes VL - 256 ER - TY - JOUR AB - Auxin belongs among major phytohormones and governs multiple aspects of plant growth and development. The establishment of auxin concentration gradients, determines, among other processes, plant organ positioning and growth responses to environmental stimuli. Herein we report the synthesis of new NBD- or DNS-labelled IAA derivatives and the elucidation of their biological activity, fluorescence properties and subcellular accumulation patterns in planta. These novel compounds did not show auxin-like activity, but instead antagonized physiological auxin effects. The DNS-labelled derivatives FL5 and FL6 showed strong anti-auxin activity in roots and hypocotyls, which also occurred at the level of gene transcription as confirmed by quantitative PCR analysis. The auxin antagonism of our derivatives was further demonstrated in vitro using an SPR-based binding assay. The NBD-labelled compound FL4 with the best fluorescence properties proved to be unsuitable to study auxin accumulation patterns in planta. On the other hand, the strongest anti-auxin activity possessing compounds FL5 and FL6 could be useful to study binding mechanisms to auxin receptors and for manipulations of auxin-regulated processes. AU - Bieleszová, Kristýna AU - Hladík, Pavel AU - Kubala, Martin AU - Napier, Richard AU - Brunoni, Federica AU - Gelová, Zuzana AU - Fiedler, Lukas AU - Kulich, Ivan AU - Strnad, Miroslav AU - Doležal, Karel AU - Novák, Ondřej AU - Friml, Jiří AU - Žukauskaitė, Asta ID - 14447 JF - Plant Growth Regulation SN - 0167-6903 TI - New fluorescent auxin derivatives: anti-auxin activity and accumulation patterns in Arabidopsis thaliana ER - TY - JOUR AB - Mosaic analysis with double markers (MADM) technology enables the generation of genetic mosaic tissue in mice and high-resolution phenotyping at the individual cell level. Here, we present a protocol for isolating MADM-labeled cells with high yield for downstream molecular analyses using fluorescence-activated cell sorting (FACS). We describe steps for generating MADM-labeled mice, perfusion, single-cell suspension, and debris removal. We then detail procedures for cell sorting by FACS and downstream analysis. This protocol is suitable for embryonic to adult mice. For complete details on the use and execution of this protocol, please refer to Contreras et al. (2021).1 AU - Amberg, Nicole AU - Cheung, Giselle T AU - Hippenmeyer, Simon ID - 14683 IS - 1 JF - STAR Protocols KW - General Immunology and Microbiology KW - General Biochemistry KW - Genetics and Molecular Biology KW - General Neuroscience SN - 2666-1667 TI - Protocol for sorting cells from mouse brains labeled with mosaic analysis with double markers by flow cytometry VL - 5 ER - TY - JOUR AB - This paper is concerned with the problem of regularization by noise of systems of reaction–diffusion equations with mass control. It is known that strong solutions to such systems of PDEs may blow-up in finite time. Moreover, for many systems of practical interest, establishing whether the blow-up occurs or not is an open question. Here we prove that a suitable multiplicative noise of transport type has a regularizing effect. More precisely, for both a sufficiently noise intensity and a high spectrum, the blow-up of strong solutions is delayed up to an arbitrary large time. Global existence is shown for the case of exponentially decreasing mass. The proofs combine and extend recent developments in regularization by noise and in the Lp(Lq)-approach to stochastic PDEs, highlighting new connections between the two areas. AU - Agresti, Antonio ID - 12486 JF - Stochastics and Partial Differential Equations: Analysis and Computations SN - 2194-0401 TI - Delayed blow-up and enhanced diffusion by transport noise for systems of reaction-diffusion equations ER - TY - JOUR AB - We derive lower bounds on the maximal rates for multiple packings in high-dimensional Euclidean spaces. For any N > 0 and L ∈ Z ≥2 , a multiple packing is a set C of points in R n such that any point in R n lies in the intersection of at most L - 1 balls of radius √ nN around points in C . This is a natural generalization of the sphere packing problem. We study the multiple packing problem for both bounded point sets whose points have norm at most √ nP for some constant P > 0, and unbounded point sets whose points are allowed to be anywhere in R n . Given a well-known connection with coding theory, multiple packings can be viewed as the Euclidean analog of list-decodable codes, which are well-studied over finite fields. We derive the best known lower bounds on the optimal multiple packing density. This is accomplished by establishing an inequality which relates the list-decoding error exponent for additive white Gaussian noise channels, a quantity of average-case nature, to the list-decoding radius, a quantity of worst-case nature. We also derive novel bounds on the list-decoding error exponent for infinite constellations and closed-form expressions for the list-decoding error exponents for the power-constrained AWGN channel, which may be of independent interest beyond multiple packing. AU - Zhang, Yihan AU - Vatedka, Shashank ID - 14665 JF - IEEE Transactions on Information Theory SN - 0018-9448 TI - Multiple packing: Lower bounds via error exponents ER - TY - CONF AB - Lucas sequences are constant-recursive integer sequences with a long history of applications in cryptography, both in the design of cryptographic schemes and cryptanalysis. In this work, we study the sequential hardness of computing Lucas sequences over an RSA modulus. First, we show that modular Lucas sequences are at least as sequentially hard as the classical delay function given by iterated modular squaring proposed by Rivest, Shamir, and Wagner (MIT Tech. Rep. 1996) in the context of time-lock puzzles. Moreover, there is no obvious reduction in the other direction, which suggests that the assumption of sequential hardness of modular Lucas sequences is strictly weaker than that of iterated modular squaring. In other words, the sequential hardness of modular Lucas sequences might hold even in the case of an algorithmic improvement violating the sequential hardness of iterated modular squaring. Second, we demonstrate the feasibility of constructing practically-efficient verifiable delay functions based on the sequential hardness of modular Lucas sequences. Our construction builds on the work of Pietrzak (ITCS 2019) by leveraging the intrinsic connection between the problem of computing modular Lucas sequences and exponentiation in an appropriate extension field. AU - Hoffmann, Charlotte AU - Hubáček, Pavel AU - Kamath, Chethan AU - Krňák, Tomáš ID - 14693 SN - 0302-9743 T2 - 21st International Conference on Theory of Cryptography TI - (Verifiable) delay functions from Lucas sequences VL - 14372 ER - TY - CONF AB - Continuous Group-Key Agreement (CGKA) allows a group of users to maintain a shared key. It is the fundamental cryptographic primitive underlying group messaging schemes and related protocols, most notably TreeKEM, the underlying key agreement protocol of the Messaging Layer Security (MLS) protocol, a standard for group messaging by the IETF. CKGA works in an asynchronous setting where parties only occasionally must come online, and their messages are relayed by an untrusted server. The most expensive operation provided by CKGA is that which allows for a user to refresh their key material in order to achieve forward secrecy (old messages are secure when a user is compromised) and post-compromise security (users can heal from compromise). One caveat of early CGKA protocols is that these update operations had to be performed sequentially, with any user wanting to update their key material having had to receive and process all previous updates. Late versions of TreeKEM do allow for concurrent updates at the cost of a communication overhead per update message that is linear in the number of updating parties. This was shown to be indeed necessary when achieving PCS in just two rounds of communication by [Bienstock et al. TCC’20]. The recently proposed protocol CoCoA [Alwen et al. Eurocrypt’22], however, shows that this overhead can be reduced if PCS requirements are relaxed, and only a logarithmic number of rounds is required. The natural question, thus, is whether CoCoA is optimal in this setting. In this work we answer this question, providing a lower bound on the cost (concretely, the amount of data to be uploaded to the server) for CGKA protocols that heal in an arbitrary k number of rounds, that shows that CoCoA is very close to optimal. Additionally, we extend CoCoA to heal in an arbitrary number of rounds, and propose a modification of it, with a reduced communication cost for certain k. We prove our bound in a combinatorial setting where the state of the protocol progresses in rounds, and the state of the protocol in each round is captured by a set system, each set specifying a set of users who share a secret key. We show this combinatorial model is equivalent to a symbolic model capturing building blocks including PRFs and public-key encryption, related to the one used by Bienstock et al. Our lower bound is of order k•n1+1/(k-1)/log(k), where 2≤k≤log(n) is the number of updates per user the protocol requires to heal. This generalizes the n2 bound for k=2 from Bienstock et al.. This bound almost matches the k⋅n1+2/(k-1) or k2⋅n1+1/(k-1) efficiency we get for the variants of the CoCoA protocol also introduced in this paper. AU - Auerbach, Benedikt AU - Cueto Noval, Miguel AU - Pascual Perez, Guillermo AU - Pietrzak, Krzysztof Z ID - 14691 SN - 0302-9743 T2 - 21st International Conference on Theory of Cryptography TI - On the cost of post-compromise security in concurrent Continuous Group-Key Agreement VL - 14371 ER - TY - CONF AB - The generic-group model (GGM) aims to capture algorithms working over groups of prime order that only rely on the group operation, but do not exploit any additional structure given by the concrete implementation of the group. In it, it is possible to prove information-theoretic lower bounds on the hardness of problems like the discrete logarithm (DL) or computational Diffie-Hellman (CDH). Thus, since its introduction, it has served as a valuable tool to assess the concrete security provided by cryptographic schemes based on such problems. A work on the related algebraic-group model (AGM) introduced a method, used by many subsequent works, to adapt GGM lower bounds for one problem to another, by means of conceptually simple reductions. In this work, we propose an alternative approach to extend GGM bounds from one problem to another. Following an idea by Yun [EC15], we show that, in the GGM, the security of a large class of problems can be reduced to that of geometric search-problems. By reducing the security of the resulting geometric-search problems to variants of the search-by-hypersurface problem, for which information theoretic lower bounds exist, we give alternative proofs of several results that used the AGM approach. The main advantage of our approach is that our reduction from geometric search-problems works, as well, for the GGM with preprocessing (more precisely the bit-fixing GGM introduced by Coretti, Dodis and Guo [Crypto18]). As a consequence, this opens up the possibility of transferring preprocessing GGM bounds from one problem to another, also by means of simple reductions. Concretely, we prove novel preprocessing bounds on the hardness of the d-strong discrete logarithm, the d-strong Diffie-Hellman inversion, and multi-instance CDH problems, as well as a large class of Uber assumptions. Additionally, our approach applies to Shoup’s GGM without additional restrictions on the query behavior of the adversary, while the recent works of Zhang, Zhou, and Katz [AC22] and Zhandry [Crypto22] highlight that this is not the case for the AGM approach. AU - Auerbach, Benedikt AU - Hoffmann, Charlotte AU - Pascual Perez, Guillermo ID - 14692 SN - 0302-9743 T2 - 21st International Conference on Theory of Cryptography TI - Generic-group lower bounds via reductions between geometric-search problems: With and without preprocessing VL - 14371 ER - TY - JOUR AB - Generalized multifractality characterizes system size dependence of pure scaling local observables at Anderson transitions in all 10 symmetry classes of disordered systems. Recently, the concept of generalized multifractality has been extended to boundaries of critical disordered noninteracting systems. Here we study the generalized boundary multifractality in the presence of electron-electron interaction, focusing on the spin quantum Hall symmetry class (class C). Employing the two-loop renormalization group analysis within the Finkel'stein nonlinear sigma model, we compute the anomalous dimensions of the pure scaling operators located at the boundary of the system. We find that generalized boundary multifractal exponents are twice larger than their bulk counterparts. Exact symmetry relations between generalized boundary multifractal exponents in the case of noninteracting systems are explicitly broken by the interaction. AU - Babkin, Serafim AU - Burmistrov, I ID - 14690 IS - 20 JF - Physical Review B SN - 2469-9950 TI - Boundary multifractality in the spin quantum Hall symmetry class with interaction VL - 108 ER -