TY - JOUR
AB - We study properties of the volume of projections of the n-dimensional
cross-polytope $\crosp^n = \{ x \in \R^n \mid |x_1| + \dots + |x_n| \leqslant 1\}.$ We prove that the projection of $\crosp^n$ onto a k-dimensional coordinate subspace has the maximum possible volume for k=2 and for k=3.
We obtain the exact lower bound on the volume of such a projection onto a two-dimensional plane. Also, we show that there exist local maxima which are not global ones for the volume of a projection of $\crosp^n$ onto a k-dimensional subspace for any n>k⩾2.
AU - Ivanov, Grigory
ID - 9098
IS - 5
JF - Discrete Mathematics
SN - 0012365X
TI - On the volume of projections of the cross-polytope
VL - 344
ER -
TY - JOUR
AB - We show that on an Abelian variety over an algebraically closed field of positive characteristic, the obstruction to lifting an automorphism to a field of characteristic zero as a morphism vanishes if and only if it vanishes for lifting it as a derived autoequivalence. We also compare the deformation space of these two types of deformations.
AU - Srivastava, Tanya K
ID - 9099
JF - Archiv der Mathematik
SN - 0003889X
TI - Lifting automorphisms on Abelian varieties as derived autoequivalences
ER -
TY - JOUR
AB - Marine environments are inhabited by a broad representation of the tree of life, yet our understanding of speciation in marine ecosystems is extremely limited compared with terrestrial and freshwater environments. Developing a more comprehensive picture of speciation in marine environments requires that we 'dive under the surface' by studying a wider range of taxa and ecosystems is necessary for a more comprehensive picture of speciation. Although studying marine evolutionary processes is often challenging, recent technological advances in different fields, from maritime engineering to genomics, are making it increasingly possible to study speciation of marine life forms across diverse ecosystems and taxa. Motivated by recent research in the field, including the 14 contributions in this issue, we highlight and discuss six axes of research that we think will deepen our understanding of speciation in the marine realm: (a) study a broader range of marine environments and organisms; (b) identify the reproductive barriers driving speciation between marine taxa; (c) understand the role of different genomic architectures underlying reproductive isolation; (d) infer the evolutionary history of divergence using model‐based approaches; (e) study patterns of hybridization and introgression between marine taxa; and (f) implement highly interdisciplinary, collaborative research programmes. In outlining these goals, we hope to inspire researchers to continue filling this critical knowledge gap surrounding the origins of marine biodiversity.
AU - Faria, Rui
AU - Johannesson, Kerstin
AU - Stankowski, Sean
ID - 9100
IS - 1
JF - Journal of Evolutionary Biology
SN - 1010061X
TI - Speciation in marine environments: Diving under the surface
VL - 34
ER -
TY - JOUR
AB - Behavioral predispositions are innate tendencies of animals to behave in a given way without the input of learning. They increase survival chances and, due to environmental and ecological challenges, may vary substantially even between closely related taxa. These differences are likely to be especially pronounced in long-lived species like crocodilians. This order is particularly relevant for comparative cognition due to its phylogenetic proximity to birds. Here we compared early life behavioral predispositions in two Alligatoridae species. We exposed American alligator and spectacled caiman hatchlings to three different novel situations: a novel object, a novel environment that was open and a novel environment with a shelter. This was then repeated a week later. During exposure to the novel environments, alligators moved around more and explored a larger range of the arena than the caimans. When exposed to the novel object, the alligators reduced the mean distance to the novel object in the second phase, while the caimans further increased it, indicating diametrically opposite ontogenetic development in behavioral predispositions. Although all crocodilian hatchlings face comparable challenges, e.g., high predation pressure, the effectiveness of parental protection might explain the observed pattern. American alligators are apex predators capable of protecting their offspring against most dangers, whereas adult spectacled caimans are frequently predated themselves. Their distancing behavior might be related to increased predator avoidance and also explain the success of invasive spectacled caimans in the natural habitats of other crocodilians.
AU - Reber, Stephan A.
AU - Oh, Jinook
AU - Janisch, Judith
AU - Stevenson, Colin
AU - Foggett, Shaun
AU - Wilkinson, Anna
ID - 9101
JF - Animal Cognition
SN - 14359448
TI - Early life differences in behavioral predispositions in two Alligatoridae species
ER -
TY - JOUR
AB - “Hydrogen economy” could enable a carbon-neutral sustainable energy chain. However, issues with safety, storage, and transport of molecular hydrogen impede its realization. Alcohols as liquid H2 carriers could be enablers, but state-of-the-art reforming is difficult, requiring high temperatures >200 °C and pressures >25 bar, and the resulting H2 is carbonized beyond tolerance levels for direct use in fuel cells. Here, we demonstrate ambient temperature and pressure alcohol reforming in a fuel cell (ARFC) with a simultaneous electrical power output. The alcohol is oxidized at the alkaline anode, where the resulting CO2 is sequestrated as carbonate. Carbon-free H2 is liberated at the acidic cathode. The neutralization energy between the alkaline anode and the acidic cathode drives the process, particularly the unusually high entropy gain (1.27-fold ΔH). The significantly positive temperature coefficient of the resulting electromotive force allows us to harvest a large fraction of the output energy from the surrounding, achieving a thermodynamic efficiency as high as 2.27. MoS2 as the cathode catalyst allows alcohol reforming even under open-air conditions, a challenge that state-of-the-art alcohol reforming failed to overcome. We further show reforming of a wide range of alcohols. The ARFC offers an unprecedented route toward hydrogen economy as CO2 is simultaneously captured and pure H2 produced at mild conditions.
AU - Manzoor Bhat, Zahid Manzoor
AU - Thimmappa, Ravikumar
AU - Dargily, Neethu Christudas
AU - Raafik, Abdul
AU - Kottaichamy, Alagar Raja
AU - Devendrachari, Mruthyunjayachari Chattanahalli
AU - Itagi, Mahesh
AU - Makri Nimbegondi Kotresh, Harish
AU - Freunberger, Stefan Alexander
AU - Ottakam Thotiyl, Musthafa
ID - 9113
JF - ACS Sustainable Chemistry and Engineering
TI - Ambient condition alcohol reforming to hydrogen with electricity output
ER -
TY - JOUR
AB - Cesium lead halides have intrinsically unstable crystal lattices and easily transform within perovskite and nonperovskite structures. In this work, we explore the conversion of the perovskite CsPbBr3 into Cs4PbBr6 in the presence of PbS at 450 °C to produce doped nanocrystal-based composites with embedded Cs4PbBr6 nanoprecipitates. We show that PbBr2 is extracted from CsPbBr3 and diffuses into the PbS lattice with a consequent increase in the concentration of free charge carriers. This new doping strategy enables the adjustment of the density of charge carriers between 1019 and 1020 cm–3, and it may serve as a general strategy for doping other nanocrystal-based semiconductors.
AU - Calcabrini, Mariano
AU - Genc, Aziz
AU - Liu, Yu
AU - Kleinhanns, Tobias
AU - Lee, Seungho
AU - Dirin, Dmitry N.
AU - Akkerman, Quinten A.
AU - Kovalenko, Maksym V.
AU - Arbiol, Jordi
AU - Ibáñez, Maria
ID - 9118
IS - 2
JF - ACS Energy Letters
TI - Exploiting the lability of metal halide perovskites for doping semiconductor nanocomposites
VL - 6
ER -
TY - JOUR
AB - We present DILS, a deployable statistical analysis platform for conducting demographic inferences with linked selection from population genomic data using an Approximate Bayesian Computation framework. DILS takes as input single‐population or two‐population data sets (multilocus fasta sequences) and performs three types of analyses in a hierarchical manner, identifying: (a) the best demographic model to study the importance of gene flow and population size change on the genetic patterns of polymorphism and divergence, (b) the best genomic model to determine whether the effective size Ne and migration rate N, m are heterogeneously distributed along the genome (implying linked selection) and (c) loci in genomic regions most associated with barriers to gene flow. Also available via a Web interface, an objective of DILS is to facilitate collaborative research in speciation genomics. Here, we show the performance and limitations of DILS by using simulations and finally apply the method to published data on a divergence continuum composed by 28 pairs of Mytilus mussel populations/species.
AU - Fraisse, Christelle
AU - Popovic, Iva
AU - Mazoyer, Clément
AU - Spataro, Bruno
AU - Delmotte, Stéphane
AU - Romiguier, Jonathan
AU - Loire, Étienne
AU - Simon, Alexis
AU - Galtier, Nicolas
AU - Duret, Laurent
AU - Bierne, Nicolas
AU - Vekemans, Xavier
AU - Roux, Camille
ID - 9119
JF - Molecular Ecology Resources
SN - 1755098X
TI - DILS: Demographic inferences with linked selection by using ABC
ER -
TY - JOUR
AB - We show that the energy gap for the BCS gap equation is
Ξ=μ(8e−2+o(1))exp(π2μ−−√a)
in the low density limit μ→0. Together with the similar result for the critical temperature by Hainzl and Seiringer (Lett Math Phys 84: 99–107, 2008), this shows that, in the low density limit, the ratio of the energy gap and critical temperature is a universal constant independent of the interaction potential V. The results hold for a class of potentials with negative scattering length a and no bound states.
AU - Lauritsen, Asbjørn Bækgaard
ID - 9121
JF - Letters in Mathematical Physics
KW - Mathematical Physics
KW - Statistical and Nonlinear Physics
SN - 0377-9017
TI - The BCS energy gap at low density
VL - 111
ER -
TY - JOUR
AB - While several tools have been developed to study the ground state of many-body quantum spin systems, the limitations of existing techniques call for the exploration of new approaches. In this manuscript we develop an alternative analytical and numerical framework for many-body quantum spin ground states, based on the disentanglement formalism. In this approach, observables are exactly expressed as Gaussian-weighted functional integrals over scalar fields. We identify the leading contribution to these integrals, given by the saddle point of a suitable effective action. Analytically, we develop a field-theoretical expansion of the functional integrals, performed by means of appropriate Feynman rules. The expansion can be truncated to a desired order to obtain analytical approximations to observables. Numerically, we show that the disentanglement approach can be used to compute ground state expectation values from classical stochastic processes. While the associated fluctuations grow exponentially with imaginary time and the system size, this growth can be mitigated by means of an importance sampling scheme based on knowledge of the saddle point configuration. We illustrate the advantages and limitations of our methods by considering the quantum Ising model in 1, 2 and 3 spatial dimensions. Our analytical and numerical approaches are applicable to a broad class of systems, bridging concepts from quantum lattice models, continuum field theory, and classical stochastic processes.
AU - De Nicola, Stefano
ID - 9158
IS - 1
JF - Journal of Statistical Mechanics: Theory and Experiment
KW - Statistics
KW - Probability and Uncertainty
KW - Statistics and Probability
KW - Statistical and Nonlinear Physics
SN - 1742-5468
TI - Disentanglement approach to quantum spin ground states: Field theory and stochastic simulation
VL - 2021
ER -
TY - JOUR
AB - Interspecific crossing experiments have shown that sex chromosomes play a major role in reproductive isolation between many pairs of species. However, their ability to act as reproductive barriers, which hamper interspecific genetic exchange, has rarely been evaluated quantitatively compared to Autosomes. This genome-wide limitation of gene flow is essential for understanding the complete separation of species, and thus speciation. Here, we develop a mainland-island model of secondary contact between hybridizing species of an XY (or ZW) sexual system. We obtain theoretical predictions for the frequency of introgressed alleles, and the strength of the barrier to neutral gene flow for the two types of chromosomes carrying multiple interspecific barrier loci. Theoretical predictions are obtained for scenarios where introgressed alleles are rare. We show that the same analytical expressions apply for sex chromosomes and autosomes, but with different sex-averaged effective parameters. The specific features of sex chromosomes (hemizygosity and absence of recombination in the heterogametic sex) lead to reduced levels of introgression on the X (or Z) compared to autosomes. This effect can be enhanced by certain types of sex-biased forces, but it remains overall small (except when alleles causing incompatibilities are recessive). We discuss these predictions in the light of empirical data comprising model-based tests of introgression and cline surveys in various biological systems.
AU - Fraisse, Christelle
AU - Sachdeva, Himani
ID - 9168
IS - 2
JF - Genetics
SN - 1943-2631
TI - The rates of introgression and barriers to genetic exchange between hybridizing species: Sex chromosomes vs autosomes
VL - 217
ER -
TY - JOUR
AB - We show that Hilbert schemes of points on supersingular Enriques surface in characteristic 2, Hilbn(X), for n ≥ 2 are simply connected, symplectic varieties but are not irreducible symplectic as the hodge number h2,0 > 1, even though a supersingular Enriques surface is an irreducible symplectic variety. These are the classes of varieties which appear only in characteristic 2 and they show that the hodge number formula for G¨ottsche-Soergel does not hold over haracteristic 2. It also gives examples of varieties with trivial canonical class which are neither irreducible symplectic nor Calabi-Yau, thereby showing that there are strictly more classes of simply connected varieties with trivial canonical class in characteristic 2 than over C as given by Beauville-Bogolomov decomposition theorem.
AU - Srivastava, Tanya K
ID - 9173
IS - 03
JF - Bulletin des Sciences Mathematiques
SN - 0007-4497
TI - Pathologies of the Hilbert scheme of points of a supersingular Enriques surface
VL - 167
ER -
TY - JOUR
AB - Genomic imprinting is an epigenetic mechanism that results in parental allele-specific expression of ~1% of all genes in mouse and human. Imprinted genes are key developmental regulators and play pivotal roles in many biological processes such as nutrient transfer from the mother to offspring and neuronal development. Imprinted genes are also involved in human disease, including neurodevelopmental disorders, and often occur in clusters that are regulated by a common imprint control region (ICR). In extra-embryonic tissues ICRs can act over large distances, with the largest surrounding Igf2r spanning over 10 million base-pairs. Besides classical imprinted expression that shows near exclusive maternal or paternal expression, widespread biased imprinted expression has been identified mainly in brain. In this review we discuss recent developments mapping cell type specific imprinted expression in extra-embryonic tissues and neocortex in the mouse. We highlight the advantages of using an inducible uniparental chromosome disomy (UPD) system to generate cells carrying either two maternal or two paternal copies of a specific chromosome to analyze the functional consequences of genomic imprinting. Mosaic Analysis with Double Markers (MADM) allows fluorescent labeling and concomitant induction of UPD sparsely in specific cell types, and thus to over-express or suppress all imprinted genes on that chromosome. To illustrate the utility of this technique, we explain how MADM-induced UPD revealed new insights about the function of the well-studied Cdkn1c imprinted gene, and how MADM-induced UPDs led to identification of highly cell type specific phenotypes related to perturbed imprinted expression in the mouse neocortex. Finally, we give an outlook on how MADM could be used to probe cell type specific imprinted expression in other tissues in mouse, particularly in extra-embryonic tissues.
AU - Pauler, Florian
AU - Hudson, Quanah
AU - Laukoter, Susanne
AU - Hippenmeyer, Simon
ID - 9188
IS - 5
JF - Neurochemistry International
KW - Cell Biology
KW - Cellular and Molecular Neuroscience
SN - 0197-0186
TI - Inducible uniparental chromosome disomy to probe genomic imprinting at single-cell level in brain and beyond
VL - 145
ER -
TY - JOUR
AB - Transposable elements exist widely throughout plant genomes and play important roles in plant evolution. Auxin is an important regulator that is traditionally associated with root development and drought stress adaptation. The DEEPER ROOTING 1 (DRO1) gene is a key component of rice drought avoidance. Here, we identified a transposon that acts as an autonomous auxin‐responsive promoter and its presence at specific genome positions conveys physiological adaptations related to drought avoidance. Rice varieties with high and auxin‐mediated transcription of DRO1 in the root tip show deeper and longer root phenotypes and are thus better adapted to drought. The INDITTO2 transposon contains an auxin response element and displays auxin‐responsive promoter activity; it is thus able to convey auxin regulation of transcription to genes in its proximity. In the rice Acuce, which displays DRO1‐mediated drought adaptation, the INDITTO2 transposon was found to be inserted at the promoter region of the DRO1 locus. Transgenesis‐based insertion of the INDITTO2 transposon into the DRO1 promoter of the non‐adapted rice variety Nipponbare was sufficient to promote its drought avoidance. Our data identify an example of how transposons can act as promoters and convey hormonal regulation to nearby loci, improving plant fitness in response to different abiotic stresses.
AU - Zhao, Y
AU - Wu, L
AU - Fu, Q
AU - Wang, D
AU - Li, J
AU - Yao, B
AU - Yu, S
AU - Jiang, L
AU - Qian, J
AU - Zhou, X
AU - Han, L
AU - Zhao, S
AU - Ma, C
AU - Zhang, Y
AU - Luo, C
AU - Dong, Q
AU - Li, S
AU - Zhang, L
AU - Jiang, X
AU - Li, Y
AU - Luo, H
AU - Li, K
AU - Yang, J
AU - Luo, Q
AU - Li, L
AU - Peng, S
AU - Huang, H
AU - Zuo, Z
AU - Liu, C
AU - Wang, L
AU - Li, C
AU - He, X
AU - Friml, Jiří
AU - Du, Y
ID - 9189
JF - Plant, Cell & Environment
SN - 0140-7791
TI - INDITTO2 transposon conveys auxin-mediated DRO1 transcription for rice drought avoidance
ER -
TY - GEN
AB - Formal design of embedded and cyber-physical systems relies on mathematical
modeling. In this paper, we consider the model class of hybrid automata whose
dynamics are defined by affine differential equations. Given a set of
time-series data, we present an algorithmic approach to synthesize a hybrid
automaton exhibiting behavior that is close to the data, up to a specified
precision, and changes in synchrony with the data. A fundamental problem in our
synthesis algorithm is to check membership of a time series in a hybrid
automaton. Our solution integrates reachability and optimization techniques for
affine dynamical systems to obtain both a sufficient and a necessary condition
for membership, combined in a refinement framework. The algorithm processes one
time series at a time and hence can be interrupted, provide an intermediate
result, and be resumed. We report experimental results demonstrating the
applicability of our synthesis approach.
AU - Garcia Soto, Miriam
AU - Henzinger, Thomas A
AU - Schilling, Christian
ID - 9200
KW - hybrid automaton
KW - membership
KW - system identification
T2 - arXiv
TI - Synthesis of hybrid automata with affine dynamics from time-series data
ER -
TY - GEN
AB - We associate a certain tensor product lattice to any primitive integer lattice and ask about its typical shape. These lattices are related to the tangent bundle of Grassmannians and their study is motivated by Peyre's programme on "freeness" for rational points of bounded height on Fano
varieties.
AU - Browning, Timothy D
AU - Horesh, Tal
AU - Wilsch, Florian Alexander
ID - 9199
T2 - arXiv
TI - Equidistribution and freeness on Grassmannians
ER -
TY - JOUR
AB - Cryo-EM grid preparation is an important bottleneck in protein structure determination, especially for membrane proteins, typically requiring screening of a large number of conditions. We systematically investigated the effects of buffer components, blotting conditions and grid types on the outcome of grid preparation of five different membrane protein samples. Aggregation was the most common type of problem which was addressed by changing detergents, salt concentration or reconstitution of proteins into nanodiscs or amphipols. We show that the optimal concentration of detergent is between 0.05 and 0.4% and that the presence of a low concentration of detergent with a high critical micellar concentration protects the proteins from denaturation at the air-water interface. Furthermore, we discuss the strategies for achieving an adequate ice thickness, particle coverage and orientation distribution on free ice and on support films. Our findings provide a clear roadmap for comprehensive screening of conditions for cryo-EM grid preparation of membrane proteins.
AU - Kampjut, Domen
AU - Steiner, Julia
AU - Sazanov, Leonid A
ID - 9205
IS - 3
JF - iScience
TI - Cryo-EM grid optimization for membrane proteins
VL - 24
ER -
TY - JOUR
AB - The precise engineering of thermoelectric materials using nanocrystals as their building blocks has proven to be an excellent strategy to increase energy conversion efficiency. Here we present a synthetic route to produce Sb-doped PbS colloidal nanoparticles. These nanoparticles are then consolidated into nanocrystalline PbS:Sb using spark plasma sintering. We demonstrate that the introduction of Sb significantly influences the size, geometry, crystal lattice and especially the carrier concentration of PbS. The increase of charge carrier concentration achieved with the introduction of Sb translates into an increase of the electrical and thermal conductivities and a decrease of the Seebeck coefficient. Overall, PbS:Sb nanomaterial were characterized by two-fold higher thermoelectric figures of merit than undoped PbS.
AU - Cadavid, Doris
AU - Wei, Kaya
AU - Liu, Yu
AU - Zhang, Yu
AU - Li, Mengyao
AU - Genç, Aziz
AU - Berestok, Taisiia
AU - Ibáñez, Maria
AU - Shavel, Alexey
AU - Nolas, George S.
AU - Cabot, Andreu
ID - 9206
IS - 4
JF - Materials
TI - Synthesis, bottom up assembly and thermoelectric properties of Sb-doped PbS nanocrystal building blocks
VL - 14
ER -
TY - JOUR
AB - In this paper we experimentally study the transitional range of Reynolds numbers in
plane Couette–Poiseuille flow, focusing our attention on the localized turbulent structures
triggered by a strong impulsive jet and the large-scale flow generated around these
structures. We present a detailed investigation of the large-scale flow and show how
its amplitude depends on Reynolds number and amplitude perturbation. In addition,
we characterize the initial dynamics of the localized turbulent spot, which includes the
coupling between the small and large scales, as well as the dependence of the advection
speed on the large-scale flow generated around the spot. Finally, we provide the first
experimental measurements of the large-scale flow around an oblique turbulent band.
AU - Klotz, Lukasz
AU - Pavlenko, A. M.
AU - Wesfreid, J. E.
ID - 9207
JF - Journal of Fluid Mechanics
SN - 0022-1120
TI - Experimental measurements in plane Couette-Poiseuille flow: Dynamics of the large- and small-scale flow
VL - 912
ER -
TY - CONF
AB - We propose a novel hybridization method for stability analysis that over-approximates nonlinear dynamical systems by switched systems with linear inclusion dynamics. We observe that existing hybridization techniques for safety analysis that over-approximate nonlinear dynamical systems by switched affine inclusion dynamics and provide fixed approximation error, do not suffice for stability analysis. Hence, we propose a hybridization method that provides a state-dependent error which converges to zero as the state tends to the equilibrium point. The crux of our hybridization computation is an elegant recursive algorithm that uses partial derivatives of a given function to obtain upper and lower bound matrices for the over-approximating linear inclusion. We illustrate our method on some examples to demonstrate the application of the theory for stability analysis. In particular, our method is able to establish stability of a nonlinear system which does not admit a polynomial Lyapunov function.
AU - Garcia Soto, Miriam
AU - Prabhakar, Pavithra
ID - 9202
T2 - 2020 IEEE Real-Time Systems Symposium
TI - Hybridization for stability verification of nonlinear switched systems
ER -
TY - JOUR
AB - Plant fitness is largely dependent on the root, the underground organ, which, besides its anchoring function, supplies the plant body with water and all nutrients necessary for growth and development. To exploit the soil effectively, roots must constantly integrate environmental signals and react through adjustment of growth and development. Important components of the root management strategy involve a rapid modulation of the root growth kinetics and growth direction, as well as an increase of the root system radius through formation of lateral roots (LRs). At the molecular level, such a fascinating growth and developmental flexibility of root organ requires regulatory networks that guarantee stability of the developmental program but also allows integration of various environmental inputs. The plant hormone auxin is one of the principal endogenous regulators of root system architecture by controlling primary root growth and formation of LR. In this review, we discuss recent progress in understanding molecular networks where auxin is one of the main players shaping the root system and acting as mediator between endogenous cues and environmental factors.
AU - Cavallari, Nicola
AU - Artner, Christina
AU - Benková, Eva
ID - 9212
JF - Cold Spring Harbor Perspectives in Biology
SN - 1943-0264
TI - Auxin-regulated lateral root organogenesis
ER -
TY - THES
AB - In this thesis, we consider several of the most classical and fundamental problems in static analysis and formal verification, including invariant generation, reachability analysis, termination analysis of probabilistic programs, data-flow analysis, quantitative analysis of Markov chains and Markov decision processes, and the problem of data packing in cache management.
We use techniques from parameterized complexity theory, polyhedral geometry, and real algebraic geometry to significantly improve the state-of-the-art, in terms of both scalability and completeness guarantees, for the mentioned problems. In some cases, our results are the first theoretical improvements for the respective problems in two or three decades.
AU - Goharshady, Amir Kafshdar
ID - 8934
SN - 2663-337X
TI - Parameterized and algebro-geometric advances in static program analysis
ER -
TY - JOUR
AB - When short-range attractions are combined with long-range repulsions in colloidal particle systems, complex microphases can emerge. Here, we study a system of isotropic particles, which can form lamellar structures or a disordered fluid phase when temperature is varied. We show that, at equilibrium, the lamellar structure crystallizes, while out of equilibrium, the system forms a variety of structures at different shear rates and temperatures above melting. The shear-induced ordering is analyzed by means of principal component analysis and artificial neural networks, which are applied to data of reduced dimensionality. Our results reveal the possibility of inducing ordering by shear, potentially providing a feasible route to the fabrication of ordered lamellar structures from isotropic particles.
AU - Pȩkalski, J.
AU - Rzadkowski, Wojciech
AU - Panagiotopoulos, A. Z.
ID - 7956
IS - 20
JF - The Journal of chemical physics
TI - Shear-induced ordering in systems with competing interactions: A machine learning study
VL - 152
ER -
TY - JOUR
AB - Neurodevelopmental disorders (NDDs) are a class of disorders affecting brain development and function and are characterized by wide genetic and clinical variability. In this review, we discuss the multiple factors that influence the clinical presentation of NDDs, with particular attention to gene vulnerability, mutational load, and the two-hit model. Despite the complex architecture of
mutational events associated with NDDs, the various proteins involved appear to converge on common pathways, such as synaptic plasticity/function, chromatin remodelers and the mammalian target of rapamycin (mTOR) pathway. A thorough understanding of the mechanisms behind these pathways will hopefully lead to the identification of candidates that could be targeted for treatment approaches.
AU - Parenti, Ilaria
AU - Garcia Rabaneda, Luis E
AU - Schön, Hanna
AU - Novarino, Gaia
ID - 7957
IS - 8
JF - Trends in Neurosciences
SN - 01662236
TI - Neurodevelopmental disorders: From genetics to functional pathways
VL - 43
ER -
TY - JOUR
AB - Let A={A1,…,An} be a family of sets in the plane. For 0≤i2b be integers. We prove that if each k-wise or (k+1)-wise intersection of sets from A has at most b path-connected components, which all are open, then fk+1=0 implies fk≤cfk−1 for some positive constant c depending only on b and k. These results also extend to two-dimensional compact surfaces.
AU - Kalai, Gil
AU - Patakova, Zuzana
ID - 7960
JF - Discrete and Computational Geometry
SN - 01795376
TI - Intersection patterns of planar sets
VL - 64
ER -
TY - JOUR
AB - A string graph is the intersection graph of a family of continuous arcs in the plane. The intersection graph of a family of plane convex sets is a string graph, but not all string graphs can be obtained in this way. We prove the following structure theorem conjectured by Janson and Uzzell: The vertex set of almost all string graphs on n vertices can be partitioned into five cliques such that some pair of them is not connected by any edge (n→∞). We also show that every graph with the above property is an intersection graph of plane convex sets. As a corollary, we obtain that almost all string graphs on n vertices are intersection graphs of plane convex sets.
AU - Pach, János
AU - Reed, Bruce
AU - Yuditsky, Yelena
ID - 7962
IS - 4
JF - Discrete and Computational Geometry
SN - 01795376
TI - Almost all string graphs are intersection graphs of plane convex sets
VL - 63
ER -
TY - CONF
AB - For 1≤m≤n, we consider a natural m-out-of-n multi-instance scenario for a public-key encryption (PKE) scheme. An adversary, given n independent instances of PKE, wins if he breaks at least m out of the n instances. In this work, we are interested in the scaling factor of PKE schemes, SF, which measures how well the difficulty of breaking m out of the n instances scales in m. That is, a scaling factor SF=ℓ indicates that breaking m out of n instances is at least ℓ times more difficult than breaking one single instance. A PKE scheme with small scaling factor hence provides an ideal target for mass surveillance. In fact, the Logjam attack (CCS 2015) implicitly exploited, among other things, an almost constant scaling factor of ElGamal over finite fields (with shared group parameters).
For Hashed ElGamal over elliptic curves, we use the generic group model to argue that the scaling factor depends on the scheme's granularity. In low granularity, meaning each public key contains its independent group parameter, the scheme has optimal scaling factor SF=m; In medium and high granularity, meaning all public keys share the same group parameter, the scheme still has a reasonable scaling factor SF=√m. Our findings underline that instantiating ElGamal over elliptic curves should be preferred to finite fields in a multi-instance scenario.
As our main technical contribution, we derive new generic-group lower bounds of Ω(√(mp)) on the difficulty of solving both the m-out-of-n Gap Discrete Logarithm and the m-out-of-n Gap Computational Diffie-Hellman problem over groups of prime order p, extending a recent result by Yun (EUROCRYPT 2015). We establish the lower bound by studying the hardness of a related computational problem which we call the search-by-hypersurface problem.
AU - Auerbach, Benedikt
AU - Giacon, Federico
AU - Kiltz, Eike
ID - 7966
SN - 0302-9743
T2 - Advances in Cryptology – EUROCRYPT 2020
TI - Everybody’s a target: Scalability in public-key encryption
VL - 12107
ER -
TY - JOUR
AB - Organic materials are known to feature long spin-diffusion times, originating in a generally small spin–orbit coupling observed in these systems. From that perspective, chiral molecules acting as efficient spin selectors pose a puzzle that attracted a lot of attention in recent years. Here, we revisit the physical origins of chiral-induced spin selectivity (CISS) and propose a simple analytic minimal model to describe it. The model treats a chiral molecule as an anisotropic wire with molecular dipole moments aligned arbitrarily with respect to the wire’s axes and is therefore quite general. Importantly, it shows that the helical structure of the molecule is not necessary to observe CISS and other chiral nonhelical molecules can also be considered as potential candidates for the CISS effect. We also show that the suggested simple model captures the main characteristics of CISS observed in the experiment, without the need for additional constraints employed in the previous studies. The results pave the way for understanding other related physical phenomena where the CISS effect plays an essential role.
AU - Ghazaryan, Areg
AU - Paltiel, Yossi
AU - Lemeshko, Mikhail
ID - 7968
IS - 21
JF - The Journal of Physical Chemistry C
SN - 1932-7447
TI - Analytic model of chiral-induced spin selectivity
VL - 124
ER -
TY - JOUR
AB - Multilayer graphene lattices allow for an additional tunability of the band structure by the strong perpendicular electric field. In particular, the emergence of the new multiple Dirac points in ABA stacked trilayer graphene subject to strong transverse electric fields was proposed theoretically and confirmed experimentally. These new Dirac points dubbed “gullies” emerge from the interplay between strong electric field and trigonal warping. In this work, we first characterize the properties of new emergent Dirac points and show that the electric field can be used to tune the distance between gullies in the momentum space. We demonstrate that the band structure has multiple Lifshitz transitions and higher-order singularity of “monkey saddle” type. Following the characterization of the band structure, we consider the spectrum of Landau levels and structure of their wave functions. In the limit of strong electric fields when gullies are well separated in momentum space, they give rise to triply degenerate Landau levels. In the second part of this work, we investigate how degeneracy between three gully Landau levels is lifted in the presence of interactions. Within the Hartree-Fock approximation we show that the symmetry breaking state interpolates between the fully gully polarized state that breaks C3 symmetry at high displacement field and the gully symmetric state when the electric field is decreased. The discontinuous transition between these two states is driven by enhanced intergully tunneling and exchange. We conclude by outlining specific experimental predictions for the existence of such a symmetry-breaking state.
AU - Rao, Peng
AU - Serbyn, Maksym
ID - 7971
IS - 24
JF - Physical Review B
SN - 2469-9950
TI - Gully quantum Hall ferromagnetism in biased trilayer graphene
VL - 101
ER -
TY - JOUR
AB - The goal of limiting global warming to 1.5 °C requires a drastic reduction in CO2 emissions across many sectors of the world economy. Batteries are vital to this endeavor, whether used in electric vehicles, to store renewable electricity, or in aviation. Present lithium-ion technologies are preparing the public for this inevitable change, but their maximum theoretical specific capacity presents a limitation. Their high cost is another concern for commercial viability. Metal–air batteries have the highest theoretical energy density of all possible secondary battery technologies and could yield step changes in energy storage, if their practical difficulties could be overcome. The scope of this review is to provide an objective, comprehensive, and authoritative assessment of the intensive work invested in nonaqueous rechargeable metal–air batteries over the past few years, which identified the key problems and guides directions to solve them. We focus primarily on the challenges and outlook for Li–O2 cells but include Na–O2, K–O2, and Mg–O2 cells for comparison. Our review highlights the interdisciplinary nature of this field that involves a combination of materials chemistry, electrochemistry, computation, microscopy, spectroscopy, and surface science. The mechanisms of O2 reduction and evolution are considered in the light of recent findings, along with developments in positive and negative electrodes, electrolytes, electrocatalysis on surfaces and in solution, and the degradative effect of singlet oxygen, which is typically formed in Li–O2 cells.
AU - Kwak, WJ
AU - Sharon, D
AU - Xia, C
AU - Kim, H
AU - Johnson, LR
AU - Bruce, PG
AU - Nazar, LF
AU - Sun, YK
AU - Frimer, AA
AU - Noked, M
AU - Freunberger, Stefan Alexander
AU - Aurbach, D
ID - 7985
IS - 14
JF - Chemical Reviews
SN - 0009-2665
TI - Lithium-oxygen batteries and related systems: Potential, status, and future
VL - 120
ER -
TY - CONF
AB - We prove general topological Radon-type theorems for sets in ℝ^d, smooth real manifolds or finite dimensional simplicial complexes. Combined with a recent result of Holmsen and Lee, it gives fractional Helly theorem, and consequently the existence of weak ε-nets as well as a (p,q)-theorem. More precisely: Let X be either ℝ^d, smooth real d-manifold, or a finite d-dimensional simplicial complex. Then if F is a finite, intersection-closed family of sets in X such that the ith reduced Betti number (with ℤ₂ coefficients) of any set in F is at most b for every non-negative integer i less or equal to k, then the Radon number of F is bounded in terms of b and X. Here k is the smallest integer larger or equal to d/2 - 1 if X = ℝ^d; k=d-1 if X is a smooth real d-manifold and not a surface, k=0 if X is a surface and k=d if X is a d-dimensional simplicial complex. Using the recent result of the author and Kalai, we manage to prove the following optimal bound on fractional Helly number for families of open sets in a surface: Let F be a finite family of open sets in a surface S such that the intersection of any subfamily of F is either empty, or path-connected. Then the fractional Helly number of F is at most three. This also settles a conjecture of Holmsen, Kim, and Lee about an existence of a (p,q)-theorem for open subsets of a surface.
AU - Patakova, Zuzana
ID - 7989
SN - 18688969
T2 - 36th International Symposium on Computational Geometry
TI - Bounding radon number via Betti numbers
VL - 164
ER -
TY - CONF
AB - Given a finite point set P in general position in the plane, a full triangulation is a maximal straight-line embedded plane graph on P. A partial triangulation on P is a full triangulation of some subset P' of P containing all extreme points in P. A bistellar flip on a partial triangulation either flips an edge, removes a non-extreme point of degree 3, or adds a point in P ⧵ P' as vertex of degree 3. The bistellar flip graph has all partial triangulations as vertices, and a pair of partial triangulations is adjacent if they can be obtained from one another by a bistellar flip. The goal of this paper is to investigate the structure of this graph, with emphasis on its connectivity. For sets P of n points in general position, we show that the bistellar flip graph is (n-3)-connected, thereby answering, for sets in general position, an open questions raised in a book (by De Loera, Rambau, and Santos) and a survey (by Lee and Santos) on triangulations. This matches the situation for the subfamily of regular triangulations (i.e., partial triangulations obtained by lifting the points and projecting the lower convex hull), where (n-3)-connectivity has been known since the late 1980s through the secondary polytope (Gelfand, Kapranov, Zelevinsky) and Balinski’s Theorem. Our methods also yield the following results (see the full version [Wagner and Welzl, 2020]): (i) The bistellar flip graph can be covered by graphs of polytopes of dimension n-3 (products of secondary polytopes). (ii) A partial triangulation is regular, if it has distance n-3 in the Hasse diagram of the partial order of partial subdivisions from the trivial subdivision. (iii) All partial triangulations are regular iff the trivial subdivision has height n-3 in the partial order of partial subdivisions. (iv) There are arbitrarily large sets P with non-regular partial triangulations, while every proper subset has only regular triangulations, i.e., there are no small certificates for the existence of non-regular partial triangulations (answering a question by F. Santos in the unexpected direction).
AU - Wagner, Uli
AU - Welzl, Emo
ID - 7990
SN - 18688969
T2 - 36th International Symposium on Computational Geometry
TI - Connectivity of triangulation flip graphs in the plane (Part II: Bistellar flips)
VL - 164
ER -
TY - CONF
AB - We define and study a discrete process that generalizes the convex-layer decomposition of a planar point set. Our process, which we call homotopic curve shortening (HCS), starts with a closed curve (which might self-intersect) in the presence of a set P⊂ ℝ² of point obstacles, and evolves in discrete steps, where each step consists of (1) taking shortcuts around the obstacles, and (2) reducing the curve to its shortest homotopic equivalent. We find experimentally that, if the initial curve is held fixed and P is chosen to be either a very fine regular grid or a uniformly random point set, then HCS behaves at the limit like the affine curve-shortening flow (ACSF). This connection between HCS and ACSF generalizes the link between "grid peeling" and the ACSF observed by Eppstein et al. (2017), which applied only to convex curves, and which was studied only for regular grids. We prove that HCS satisfies some properties analogous to those of ACSF: HCS is invariant under affine transformations, preserves convexity, and does not increase the total absolute curvature. Furthermore, the number of self-intersections of a curve, or intersections between two curves (appropriately defined), does not increase. Finally, if the initial curve is simple, then the number of inflection points (appropriately defined) does not increase.
AU - Avvakumov, Sergey
AU - Nivasch, Gabriel
ID - 7991
SN - 18688969
T2 - 36th International Symposium on Computational Geometry
TI - Homotopic curve shortening and the affine curve-shortening flow
VL - 164
ER -
TY - CONF
AB - Let K be a convex body in ℝⁿ (i.e., a compact convex set with nonempty interior). Given a point p in the interior of K, a hyperplane h passing through p is called barycentric if p is the barycenter of K ∩ h. In 1961, Grünbaum raised the question whether, for every K, there exists an interior point p through which there are at least n+1 distinct barycentric hyperplanes. Two years later, this was seemingly resolved affirmatively by showing that this is the case if p=p₀ is the point of maximal depth in K. However, while working on a related question, we noticed that one of the auxiliary claims in the proof is incorrect. Here, we provide a counterexample; this re-opens Grünbaum’s question. It follows from known results that for n ≥ 2, there are always at least three distinct barycentric cuts through the point p₀ ∈ K of maximal depth. Using tools related to Morse theory we are able to improve this bound: four distinct barycentric cuts through p₀ are guaranteed if n ≥ 3.
AU - Patakova, Zuzana
AU - Tancer, Martin
AU - Wagner, Uli
ID - 7992
SN - 18688969
T2 - 36th International Symposium on Computational Geometry
TI - Barycentric cuts through a convex body
VL - 164
ER -
TY - CONF
AB - In the recent study of crossing numbers, drawings of graphs that can be extended to an arrangement of pseudolines (pseudolinear drawings) have played an important role as they are a natural combinatorial extension of rectilinear (or straight-line) drawings. A characterization of the pseudolinear drawings of K_n was found recently. We extend this characterization to all graphs, by describing the set of minimal forbidden subdrawings for pseudolinear drawings. Our characterization also leads to a polynomial-time algorithm to recognize pseudolinear drawings and construct the pseudolines when it is possible.
AU - Arroyo Guevara, Alan M
AU - Bensmail, Julien
AU - Bruce Richter, R.
ID - 7994
SN - 18688969
T2 - 36th International Symposium on Computational Geometry
TI - Extending drawings of graphs to arrangements of pseudolines
VL - 164
ER -
TY - JOUR
AB - When divergent populations are connected by gene flow, the establishment of complete reproductive isolation usually requires the joint action of multiple barrier effects. One example where multiple barrier effects are coupled consists of a single trait that is under divergent natural selection and also mediates assortative mating. Such multiple‐effect traits can strongly reduce gene flow. However, there are few cases where patterns of assortative mating have been described quantitatively and their impact on gene flow has been determined. Two ecotypes of the coastal marine snail, Littorina saxatilis , occur in North Atlantic rocky‐shore habitats dominated by either crab predation or wave action. There is evidence for divergent natural selection acting on size, and size‐assortative mating has previously been documented. Here, we analyze the mating pattern in L. saxatilis with respect to size in intensively sampled transects across boundaries between the habitats. We show that the mating pattern is mostly conserved between ecotypes and that it generates both assortment and directional sexual selection for small male size. Using simulations, we show that the mating pattern can contribute to reproductive isolation between ecotypes but the barrier to gene flow is likely strengthened more by sexual selection than by assortment.
AU - Perini, Samuel
AU - Rafajlović, Marina
AU - Westram, Anja M
AU - Johannesson, Kerstin
AU - Butlin, Roger K.
ID - 7995
IS - 7
JF - Evolution
SN - 00143820
TI - Assortative mating, sexual selection, and their consequences for gene flow in Littorina
VL - 74
ER -
TY - THES
AB - Quantum computation enables the execution of algorithms that have exponential complexity. This might open the path towards the synthesis of new materials or medical drugs, optimization of transport or financial strategies etc., intractable on even the fastest classical computers. A quantum computer consists of interconnected two level quantum systems, called qubits, that satisfy DiVincezo’s criteria. Worldwide, there are ongoing efforts to find the qubit architecture which will unite quantum error correction compatible single and two qubit fidelities, long distance qubit to qubit coupling and
calability. Superconducting qubits have gone the furthest in this race, demonstrating an algorithm running on 53 coupled qubits, but still the fidelities are not even close to those required for realizing a single logical qubit. emiconductor qubits offer extremely good characteristics, but they are currently investigated across different platforms. Uniting those good characteristics into a single platform might be a big step towards the quantum computer realization.
Here we describe the implementation of a hole spin qubit hosted in a Ge hut wire double quantum dot. The high and tunable spin-orbit coupling together with a heavy hole state character is expected to allow fast spin manipulation and long coherence times. Furthermore large lever arms, for hut wire devices, should allow good coupling to superconducting resonators enabling efficient long distance spin to spin coupling and a sensitive gate reflectometry spin readout. The developed cryogenic setup (printed circuit board sample holders, filtering, high-frequency wiring) enabled us to perform low temperature spin dynamics experiments. Indeed, we measured the fastest single spin qubit Rabi frequencies reported so far, reaching 140 MHz, while the dephasing times of 130 ns oppose the long decoherence predictions. In order to further investigate this, a double quantum dot gate was connected directly to a lumped element
resonator which enabled gate reflectometry readout. The vanishing inter-dot transition signal, for increasing external magnetic field, revealed the spin nature of the measured quantity.
AU - Kukucka, Josip
ID - 7996
TI - Implementation of a hole spin qubit in Ge hut wires and dispersive spin sensing
ER -
TY - JOUR
AB - Linking epigenetic marks to clinical outcomes improves insight into molecular processes, disease prediction, and therapeutic target identification. Here, a statistical approach is presented to infer the epigenetic architecture of complex disease, determine the variation captured by epigenetic effects, and estimate phenotype-epigenetic probe associations jointly. Implicitly adjusting for probe correlations, data structure (cell-count or relatedness), and single-nucleotide polymorphism (SNP) marker effects, improves association estimates and in 9,448 individuals, 75.7% (95% CI 71.70–79.3) of body mass index (BMI) variation and 45.6% (95% CI 37.3–51.9) of cigarette consumption variation was captured by whole blood methylation array data. Pathway-linked probes of blood cholesterol, lipid transport and sterol metabolism for BMI, and xenobiotic stimuli response for smoking, showed >1.5 times larger associations with >95% posterior inclusion probability. Prediction accuracy improved by 28.7% for BMI and 10.2% for smoking over a LASSO model, with age-, and tissue-specificity, implying associations are a phenotypic consequence rather than causal.
AU - Trejo Banos, D
AU - McCartney, DL
AU - Patxot, M
AU - Anchieri, L
AU - Battram, T
AU - Christiansen, C
AU - Costeira, R
AU - Walker, RM
AU - Morris, SW
AU - Campbell, A
AU - Zhang, Q
AU - Porteous, DJ
AU - McRae, AF
AU - Wray, NR
AU - Visscher, PM
AU - Haley, CS
AU - Evans, KL
AU - Deary, IJ
AU - McIntosh, AM
AU - Hemani, G
AU - Bell, JT
AU - Marioni, RE
AU - Robinson, Matthew Richard
ID - 7999
JF - Nature Communications
SN - 2041-1723
TI - Bayesian reassessment of the epigenetic architecture of complex traits
VL - 11
ER -
TY - JOUR
AB - Post-tetanic potentiation (PTP) is an attractive candidate mechanism for hippocampus-dependent short-term memory. Although PTP has a uniquely large magnitude at hippocampal mossy fiber-CA3 pyramidal neuron synapses, it is unclear whether it can be induced by natural activity and whether its lifetime is sufficient to support short-term memory. We combined in vivo recordings from granule cells (GCs), in vitro paired recordings from mossy fiber terminals and postsynaptic CA3 neurons, and “flash and freeze” electron microscopy. PTP was induced at single synapses and showed a low induction threshold adapted to sparse GC activity in vivo. PTP was mainly generated by enlargement of the readily releasable pool of synaptic vesicles, allowing multiplicative interaction with other plasticity forms. PTP was associated with an increase in the docked vesicle pool, suggesting formation of structural “pool engrams.” Absence of presynaptic activity extended the lifetime of the potentiation, enabling prolonged information storage in the hippocampal network.
AU - Vandael, David H
AU - Borges Merjane, Carolina
AU - Zhang, Xiaomin
AU - Jonas, Peter M
ID - 8001
IS - 3
JF - Neuron
SN - 0896-6273
TI - Short-term plasticity at hippocampal mossy fiber synapses is induced by natural activity patterns and associated with vesicle pool engram formation
VL - 107
ER -
TY - JOUR
AB - Wound healing in plant tissues, consisting of rigid cell wall-encapsulated cells, represents a considerable challenge and occurs through largely unknown mechanisms distinct from those in animals. Owing to their inability to migrate, plant cells rely on targeted cell division and expansion to regenerate wounds. Strict coordination of these wound-induced responses is essential to ensure efficient, spatially restricted wound healing. Single-cell tracking by live imaging allowed us to gain mechanistic insight into the wound perception and coordination of wound responses after laser-based wounding in Arabidopsis root. We revealed a crucial contribution of the collapse of damaged cells in wound perception and detected an auxin increase specific to cells immediately adjacent to the wound. This localized auxin increase balances wound-induced cell expansion and restorative division rates in a dose-dependent manner, leading to tumorous overproliferation when the canonical TIR1 auxin signaling is disrupted. Auxin and wound-induced turgor pressure changes together also spatially define the activation of key components of regeneration, such as the transcription regulator ERF115. Our observations suggest that the wound signaling involves the sensing of collapse of damaged cells and a local auxin signaling activation to coordinate the downstream transcriptional responses in the immediate wound vicinity.
AU - Hörmayer, Lukas
AU - Montesinos López, Juan C
AU - Marhavá, Petra
AU - Benková, Eva
AU - Yoshida, Saiko
AU - Friml, Jiří
ID - 8002
IS - 26
JF - Proceedings of the National Academy of Sciences
SN - 0027-8424
TI - Wounding-induced changes in cellular pressure and localized auxin signalling spatially coordinate restorative divisions in roots
VL - 117
ER -
TY - JOUR
AB - Relaxation to a thermal state is the inevitable fate of nonequilibrium interacting quantum systems without special conservation laws. While thermalization in one-dimensional systems can often be suppressed by integrability mechanisms, in two spatial dimensions thermalization is expected to be far more effective due to the increased phase space. In this work we propose a general framework for escaping or delaying the emergence of the thermal state in two-dimensional arrays of Rydberg atoms via the mechanism of quantum scars, i.e., initial states that fail to thermalize. The suppression of thermalization is achieved in two complementary ways: by adding local perturbations or by adjusting the driving Rabi frequency according to the local connectivity of the lattice. We demonstrate that these mechanisms allow us to realize robust quantum scars in various two-dimensional lattices, including decorated lattices with nonconstant connectivity. In particular, we show that a small decrease of the Rabi frequency at the corners of the lattice is crucial for mitigating the strong boundary effects in two-dimensional systems. Our results identify synchronization as an important tool for future experiments on two-dimensional quantum scars.
AU - Michailidis, Alexios
AU - Turner, C. J.
AU - Papić, Z.
AU - Abanin, D. A.
AU - Serbyn, Maksym
ID - 8011
IS - 2
JF - Physical Review Research
SN - 2643-1564
TI - Stabilizing two-dimensional quantum scars by deformation and synchronization
VL - 2
ER -
TY - CONF
AB - Asynchronous programs are notoriously difficult to reason about because they spawn computation tasks which take effect asynchronously in a nondeterministic way. Devising inductive invariants for such programs requires understanding and stating complex relationships between an unbounded number of computation tasks in arbitrarily long executions. In this paper, we introduce inductive sequentialization, a new proof rule that sidesteps this complexity via a sequential reduction, a sequential program that captures every behavior of the original program up to reordering of coarse-grained commutative actions. A sequential reduction of a concurrent program is easy to reason about since it corresponds to a simple execution of the program in an idealized synchronous environment, where processes act in a fixed order and at the same speed. We have implemented and integrated our proof rule in the CIVL verifier, allowing us to provably derive fine-grained implementations of asynchronous programs. We have successfully applied our proof rule to a diverse set of message-passing protocols, including leader election protocols, two-phase commit, and Paxos.
AU - Kragl, Bernhard
AU - Enea, Constantin
AU - Henzinger, Thomas A
AU - Mutluergil, Suha Orhun
AU - Qadeer, Shaz
ID - 8012
SN - 9781450376136
T2 - Proceedings of the 41st ACM SIGPLAN Conference on Programming Language Design and Implementation
TI - Inductive sequentialization of asynchronous programs
ER -
TY - THES
AB - Algorithms in computational 3-manifold topology typically take a triangulation as an input and return topological information about the underlying 3-manifold. However, extracting the desired information from a triangulation (e.g., evaluating an invariant) is often computationally very expensive. In recent years this complexity barrier has been successfully tackled in some cases by importing ideas from the theory of parameterized algorithms into the realm of 3-manifolds. Various computationally hard problems were shown to be efficiently solvable for input triangulations that are sufficiently “tree-like.”
In this thesis we focus on the key combinatorial parameter in the above context: we consider the treewidth of a compact, orientable 3-manifold, i.e., the smallest treewidth of the dual graph of any triangulation thereof. By building on the work of Scharlemann–Thompson and Scharlemann–Schultens–Saito on generalized Heegaard splittings, and on the work of Jaco–Rubinstein on layered triangulations, we establish quantitative relations between the treewidth and classical topological invariants of a 3-manifold. In particular, among other results, we show that the treewidth of a closed, orientable, irreducible, non-Haken 3-manifold is always within a constant factor of its Heegaard genus.
AU - Huszár, Kristóf
ID - 8032
SN - 2663-337X
TI - Combinatorial width parameters for 3-dimensional manifolds
ER -
TY - JOUR
AB - When tiny soft ferromagnetic particles are placed along a liquid interface and exposed to a vertical magnetic field, the balance between capillary attraction and magnetic repulsion leads to self-organization into well-defined patterns. Here, we demonstrate experimentally that precessing magnetic fields induce metachronal waves on the periphery of these assemblies, similar to the ones observed in ciliates and some arthropods. The outermost layer of particles behaves like an array of cilia or legs whose sequential movement causes a net and controllable locomotion. This bioinspired many-particle swimming strategy is effective even at low Reynolds number, using only spatially uniform fields to generate the waves.
AU - Collard, Ylona
AU - Grosjean, Galien M
AU - Vandewalle, Nicolas
ID - 8036
JF - Communications Physics
TI - Magnetically powered metachronal waves induce locomotion in self-assemblies
VL - 3
ER -
TY - JOUR
AB - Microelectromechanical systems and integrated photonics provide the basis for many reliable and compact circuit elements in modern communication systems. Electro-opto-mechanical devices are currently one of the leading approaches to realize ultra-sensitive, low-loss transducers for an emerging quantum information technology. Here we present an on-chip microwave frequency converter based on a planar aluminum on silicon nitride platform that is compatible with slot-mode coupled photonic crystal cavities. We show efficient frequency conversion between two propagating microwave modes mediated by the radiation pressure interaction with a metalized dielectric nanobeam oscillator. We achieve bidirectional coherent conversion with a total device efficiency of up to ~60%, a dynamic range of 2 × 10^9 photons/s and an instantaneous bandwidth of up to 1.7 kHz. A high fidelity quantum state transfer would be possible if the drive dependent output noise of currently ~14 photons s^−1 Hz^−1 is further reduced. Such a silicon nitride based transducer is in situ reconfigurable and could be used for on-chip classical and quantum signal routing and filtering, both for microwave and hybrid microwave-optical applications.
AU - Fink, Johannes M
AU - Kalaee, M.
AU - Norte, R.
AU - Pitanti, A.
AU - Painter, O.
ID - 8038
IS - 3
JF - Quantum Science and Technology
TI - Efficient microwave frequency conversion mediated by a photonics compatible silicon nitride nanobeam oscillator
VL - 5
ER -
TY - JOUR
AB - In the present work, we report a solution-based strategy to produce crystallographically textured SnSe bulk nanomaterials and printed layers with optimized thermoelectric performance in the direction normal to the substrate. Our strategy is based on the formulation of a molecular precursor that can be continuously decomposed to produce a SnSe powder or printed into predefined patterns. The precursor formulation and decomposition conditions are optimized to produce pure phase 2D SnSe nanoplates. The printed layer and the bulk material obtained after hot press displays a clear preferential orientation of the crystallographic domains, resulting in an ultralow thermal conductivity of 0.55 W m–1 K–1 in the direction normal to the substrate. Such textured nanomaterials present highly anisotropic properties with the best thermoelectric performance in plane, i.e., in the directions parallel to the substrate, which coincide with the crystallographic bc plane of SnSe. This is an unfortunate characteristic because thermoelectric devices are designed to create/harvest temperature gradients in the direction normal to the substrate. We further demonstrate that this limitation can be overcome with the introduction of small amounts of tellurium in the precursor. The presence of tellurium allows one to reduce the band gap and increase both the charge carrier concentration and the mobility, especially the cross plane, with a minimal decrease of the Seebeck coefficient. These effects translate into record out of plane ZT values at 800 K.
AU - Zhang, Yu
AU - Liu, Yu
AU - Xing, Congcong
AU - Zhang, Ting
AU - Li, Mengyao
AU - Pacios, Mercè
AU - Yu, Xiaoting
AU - Arbiol, Jordi
AU - Llorca, Jordi
AU - Cadavid, Doris
AU - Ibáñez, Maria
AU - Cabot, Andreu
ID - 8039
IS - 24
JF - ACS Applied Materials and Interfaces
TI - Tin selenide molecular precursor for the solution processing of thermoelectric materials and devices
VL - 12
ER -
TY - JOUR
AB - We consider systems of N bosons in a box of volume one, interacting through a repulsive two-body potential of the form κN3β−1V(Nβx). For all 0<β<1, and for sufficiently small coupling constant κ>0, we establish the validity of Bogolyubov theory, identifying the ground state energy and the low-lying excitation spectrum up to errors that vanish in the limit of large N.
AU - Boccato, Chiara
AU - Brennecke, Christian
AU - Cenatiempo, Serena
AU - Schlein, Benjamin
ID - 8042
IS - 7
JF - Journal of the European Mathematical Society
SN - 14359855
TI - The excitation spectrum of Bose gases interacting through singular potentials
VL - 22
ER -
TY - JOUR
AB - With decreasing Reynolds number, Re, turbulence in channel flow becomes spatio-temporally intermittent and self-organises into solitary stripes oblique to the mean flow direction. We report here the existence of localised nonlinear travelling wave solutions of the Navier–Stokes equations possessing this obliqueness property. Such solutions are identified numerically using edge tracking coupled with arclength continuation. All solutions emerge in saddle-node bifurcations at values of Re lower than the non-localised solutions. Relative periodic orbit solutions bifurcating from branches of travelling waves have also been computed. A complete parametric study is performed, including their stability, the investigation of their large-scale flow, and the robustness to changes of the numerical domain.
AU - Paranjape, Chaitanya S
AU - Duguet, Yohann
AU - Hof, Björn
ID - 8043
JF - Journal of Fluid Mechanics
SN - 00221120
TI - Oblique stripe solutions of channel flow
VL - 897
ER -
TY - JOUR
AB - Water-in-salt electrolytes based on highly concentrated bis(trifluoromethyl)sulfonimide (TFSI) promise aqueous electrolytes with stabilities approaching 3 V. However, especially with an electrode approaching the cathodic (reductive) stability, cycling stability is insufficient. While stability critically relies on a solid electrolyte interphase (SEI), the mechanism behind the cathodic stability limit remains unclear. Here, we reveal two distinct reduction potentials for the chemical environments of ‘free’ and ‘bound’ water and that both contribute to SEI formation. Free-water is reduced ~1V above bound water in a hydrogen evolution reaction (HER) and responsible for SEI formation via reactive intermediates of the HER; concurrent LiTFSI precipitation/dissolution establishes a dynamic interface. The free-water population emerges, therefore, as the handle to extend the cathodic limit of aqueous electrolytes and the battery cycling stability.
AU - Bouchal, Roza
AU - Li, Zhujie
AU - Bongu, Chandra
AU - Le Vot, Steven
AU - Berthelot, Romain
AU - Rotenberg, Benjamin
AU - Favier, Frederic
AU - Freunberger, Stefan Alexander
AU - Salanne, Mathieu
AU - Fontaine, Olivier
ID - 8057
IS - 37
JF - Angewandte Chemie
SN - 0044-8249
TI - Competitive salt precipitation/dissolution during free‐water reduction in water‐in‐salt electrolyte
VL - 132
ER -
TY - GEN
AB - We present a generative model of images that explicitly reasons over the set
of objects they show. Our model learns a structured latent representation that
separates objects from each other and from the background; unlike prior works,
it explicitly represents the 2D position and depth of each object, as well as
an embedding of its segmentation mask and appearance. The model can be trained
from images alone in a purely unsupervised fashion without the need for object
masks or depth information. Moreover, it always generates complete objects,
even though a significant fraction of training images contain occlusions.
Finally, we show that our model can infer decompositions of novel images into
their constituent objects, including accurate prediction of depth ordering and
segmentation of occluded parts.
AU - Anciukevicius, Titas
AU - Lampert, Christoph
AU - Henderson, Paul M
ID - 8063
T2 - arXiv
TI - Object-centric image generation with factored depths, locations, and appearances
ER -
TY - GEN
AB - With the lithium-ion technology approaching its intrinsic limit with graphite-based anodes, lithium metal is recently receiving renewed interest from the battery community as potential high capacity anode for next-generation rechargeable batteries. In this focus paper, we review the main advances in this field since the first attempts in the
mid-1970s. Strategies for enabling reversible cycling and avoiding dendrite growth are thoroughly discussed, including specific applications in all-solid-state (polymeric and inorganic), Lithium-sulphur and Li-O2 (air) batteries. A particular attention is paid to review recent developments in regard of prototype manufacturing and current state-ofthe-art of these battery technologies with respect to the 2030 targets of the EU Integrated Strategic Energy Technology Plan (SET-Plan) Action 7.
AU - Varzi, Alberto
AU - Thanner, Katharina
AU - Scipioni, Roberto
AU - Di Lecce, Daniele
AU - Hassoun, Jusef
AU - Dörfler, Susanne
AU - Altheus, Holger
AU - Kaskel, Stefan
AU - Prehal, Christian
AU - Freunberger, Stefan Alexander
ID - 8067
KW - Battery
KW - Lithium metal
KW - Lithium-sulphur
KW - Lithium-air
KW - All-solid-state
SN - 2664-1690
TI - Current status and future perspectives of Lithium metal batteries
ER -