cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Optimal interlayer hopping and high temperature Bose-Einstein condensation of local pairs in quasi 2D superconductors
Creators: name: Kornilovitch, P. E.
name: Hague, J. P.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Both FeSe and cuprate superconductors are quasi 2D materials with high transition temperatures and local fermion pairs. Motivated by such systems, we investigate real space pairing of fermions in an anisotropic lattice model with intersite attraction, V, and strong local Coulomb repulsion, U, leading to a determination of the optimal conditions for superconductivity from Bose-Einstein condensation. Our aim is to gain insight as to why high temperature superconductors tend to be quasi 2D. We make both analytically and numerically exact solutions for two body local pairing applicable to intermediate and strong V. We find that the Bose Einstein condensation temperature of such local pairs is maximal when hopping between layers is intermediate relative to in-plane hopping, indicating that the quasi 2D nature of unconventional superconductors has an important contribution to their high transition temperatures.
description: Published version. New title
Transmission and Lesion Progression of Treponeme-Associated Hoof Disease in Captive Elk (Cervus Canadensis)
Creators: name: Robinson, Zachary B
Publisher: name: Washington State University
Year: 2024
Subjects: Cervus canadensis
elk
experimental transmission
transmission
Treponeme-associated hoof disease
wildlife disease
Animal diseases

description: Treponeme-associated hoof disease (TAHD) is a debilitating disease of free-ranging elk (Cervus canadensis) in the northwestern U.S. While Treponema spp. is associated with lesions, the etiology and transmissibility between elk are unknown. Our objective was to determine whether the disease can be environmentally transmitted to captive elk. Four individually housed treatment elk and two control elk were challenged with soil mixed with inoculum prepared from free-ranging elk hooves from TAHD-positive elk or autoclaved hooves from normal elk, respectively. The challenge material for each group was applied to the interdigital space (IDS) and added to pre-existing soil in each stall. Eight challenges were conducted at 1–4-week intervals and lesion development was assessed during a 138-day challenge period that was followed by a 170-day monitoring period to document lesion progression. All treatment elk, but no control elk, developed gross and histologic lesions consistent with TAHD. Treponema spp. were detected using 16S amplicon sequencing from lesions in all treatment elk, but no control elk, during the challenge period. Lesions progressed from ulcerations in the interdigital space to extensive ulceration and underrunning of the hoof capsule by 35- and 173-days post-study initiation, respectively. Lameness in treatment elk was correlated to lesion development (R=0.702, p<0.001), and activity in infected elk was reduced during the challenge (p<0.001) and monitoring periods (p=0.004). Body condition at each individual elk’s study endpoint was significantly lower in treatment than control elk (p=0.006). Three of four treatment elk were euthanized when they reached humane endpoints, and one elk recovered. These results provide direct evidence that TAHD is a transmissible infectious disease in elk. As such, actions that reduce transmission risk can support disease management and prevention.
Topology in shallow-water waves: A spectral flow perspective
Creators: name: Tauber, Clément
name: Thiang, Guo Chuan
Publisher: name: arXiv
Year: 2021
Subjects: subject: Mathematical Physics (math-ph)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: In the context of topological insulators, the shallow-water model was recently shown to exhibit an anomalous bulk-edge correspondence. For the model with a boundary, the parameter space involves both longitudinal momentum and boundary conditions, and exhibits a peculiar singularity. We resolve the anomaly in question by defining a new kind of edge index as the spectral flow around this singularity. Crucially, this edge index samples a whole family of boundary conditions, and we interpret it as a boundary-driven quantized pumping. Our edge index is stable due to the topological nature of spectral flow, and we prove its correspondence with the bulk Chern number index using scattering theory and a relative version of Levinson's theorem. The full spectral flow structure of the model is also investigated.
A RETROSPECTIVE STUDY OF LAW ENFORCEMENT ACADEMY RECRUIT FITNESS OVER A 15 YEAR PERIOD
Creators: name: Gonzales, Stephen M.
Publisher: name: Zenodo
Year: 2023
Subjects: law enforcement
recruits
law enforcement academy
police
obesity
BMI

description: To prepare for the unpredictability of law enforcement as an occupation, law enforcement agencies develop curriculum with the intention of improving a recruit’s physical fitness so that they can effectively perform occupational tasks. Muscular strength, endurance, flexibility, and aerobic capacity are a few components of fitness that academies will address. However, like other tactical professions, law enforcement draws from the general population for its recruiting needs. In the past two decades, obesity and physical inactivity have increased in the adult population, potentially limiting the ability of recruits to successfully graduate from a law enforcement academy (LEA). This retrospective, cross-sectional study examined fitness and anthropometric trends at one law enforcement academy over four time periods (2003, 2006, 2009 and 2018) to determine if recruits in recent years were of poorer fitness than those of earlier years. Recruits were grouped by years and several univariate analyses of covariance (ANCOVA) (p < 0.05), with sex and age as covariates were used to determine if there were significant differences between groups. If the ANCOVA was significant, a Bonferroni post hoc adjustment for multiple pairwise comparisons were utilized. 2018 recruits had significantly higher body mass index (p < 0.05) and longer 2.4 km run times (p < 0.05) compared to all other years and worse sit-and-reach scores than 2003 (p < 0.001). Yet, 2018 recruits performed significantly better in the combined grip strength (p < 0.001), push-up (p < 0.05), sit-up (p < 0.005) and physical ability tests (p < 0.05). Training staff at LEAs should implement preliminary analysis of fitness and design an appropriate physical training plan prior to start dates.
MDERank: A Masked Document Embedding Rank Approach for Unsupervised Keyphrase Extraction
Creators: name: Zhang, Linhan
name: Chen, Qian
name: Wang, Wen
name: Deng, Chong
name: Zhang, Shiliang
name: Li, Bing
name: Wang, Wei
name: Cao, Xin
Publisher: name: arXiv
Year: 2021
Subjects: subject: Computation and Language (cs.CL)
subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences

description: Keyphrase extraction (KPE) automatically extracts phrases in a document that provide a concise summary of the core content, which benefits downstream information retrieval and NLP tasks. Previous state-of-the-art (SOTA) methods select candidate keyphrases based on the similarity between learned representations of the candidates and the document. They suffer performance degradation on long documents due to discrepancy between sequence lengths which causes mismatch between representations of keyphrase candidates and the document. In this work, we propose a novel unsupervised embedding-based KPE approach, Masked Document Embedding Rank (MDERank), to address this problem by leveraging a mask strategy and ranking candidates by the similarity between embeddings of the source document and the masked document. We further develop a KPE-oriented BERT (KPEBERT) model by proposing a novel self-supervised contrastive learning method, which is more compatible to MDERank than vanilla BERT. Comprehensive evaluations on six KPE benchmarks demonstrate that the proposed MDERank outperforms state-of-the-art unsupervised KPE approach by average 1.80 $F1@15$ improvement. MDERank further benefits from KPEBERT and overall achieves average 3.53 $F1@15$ improvement over the SOTA SIFRank. Our code is available at \url{https://github.com/LinhanZ/mderank}.
description: 13 pages, 5 figures
Branching processes with resetting as a model for cell division
Creators: name: Genthon, Arthur
name: García-García, Reinaldo
name: Lacoste, David
Publisher: name: arXiv
Year: 2021
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We study the Stochastic Thermodynamics of cell growth and division using a theoretical framework based on branching processes with resetting. Cell division may be split into two sub-processes: branching, by which a given cell gives birth to an identical copy of itself, and resetting, by which some properties of the daughter cells (such as their size or age) are reset to new values following division. We derive the first and second laws of Stochastic Thermodynamics for this process, and identify separate contributions due to branching and resetting. We apply our framework to well-known models of cell size control, such as the sizer, the timer, and the adder. We show that the entropy production of resetting is negative and that of branching is positive for these models in the regime of exponential growth of the colony. This property suggests an analogy between our model for cell growth and division and heat engines, and the introduction of a thermodynamic efficiency, which quantifies the conversion of one form of entropy production to another.
A Great Escape: resource availability and density-dependence shape population dynamics along trailing range edges
Creators: name: Siren, Alexej
Publisher: name: Zenodo
Year: 2023

description: Populations along geographical range limits are often exposed to unsuitable climate and low resource availability relative to core populations. As such, there has been a renewed focus on understanding the factors that determine range limits to better predict how species will respond to global change. Using recent theory on range limits and classical understanding of density dependence, we evaluated the influence of resource availability on the snowshoe hare Lepus americanus along its trailing range edge. We estimated variation in population density, habitat use, survival, and parasite loads to test the Great Escape Hypothesis (GEH), i.e. that density dependence determines, in part, a species' persistence along trailing edges. We found that variability in resource availability affected density and population fluctuations and led to trade-offs in survival for snowshoe hare populations in the northeastern USA. Hares living in resource-limited environments had lower and less variable population density, yet higher survival and lower parasitism compared to populations living in resource-rich environments. We suggest that density-dependent dynamics, elicited by resource availability, provide hares a unique survival advantage and partly explain persistence along their trailing edge. We hypothesize that this low-density escape from predation and parasitism occurs for other prey species along trailing edges, but the extent to which it occurs is likely conditional on the quality of matrix habitat. Our work indicates that biotic factors play an important role in shaping species' trailing edges and more detailed examination of non-climatic factors is warranted to better inform conservation and management decisions.
description: The open source software program R were used for all statistical analyses. All R packages used are listed in the manuscript or in the R files associated with the Dryad submission for this paper. We politely request to be contacted by parties interested in data reuse to discuss collaboration.Funding provided by: U.S. Fish and Wildlife Service
Crossref Funder Registry ID: http://dx.doi.org/10.13039/100000202
Award Number: Funding provided by: U.S. Forest Service
Crossref Funder Registry ID: http://dx.doi.org/10.13039/100006959
Award Number: Funding provided by: National Science Foundation
Crossref Funder Registry ID: http://dx.doi.org/10.13039/100000001
Award Number: Funding provided by: New Hampshire Fish and Game Department*
Crossref Funder Registry ID:
Award Number:
description: See methods in provided in the published paper.
Waveguide-QED-based measurement of a reservoir spectral density
Creators: name: Ciccarello, Francesco
Publisher: name: arXiv
Year: 2014
Subjects: subject: Quantum Physics (quant-ph)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: The spectral density (SD) function has a central role in the study of open quantum systems (OQSs). We discover a method allowing for a "static" measurement of the SD - i.e., it requires neither the OQS to be initially excited nor its time evolution tracked in time - which is not limited to the weak-coupling regime. This is achieved through one-dimensional photon scattering for a zero-temperature reservoir coupled to the OQS via the rotating wave approximation. We find that the SD profile is a universal simple function of the photon's reflectance and transmittance. As such, it can be straightforwardly inferred from photon's reflection and transmission spectra.
description: 6 pages, 1 figure
Activity-regulated growth of motoneurons at the neuromuscular junction is mediated by NADPH oxidases.
Creators: name: Sobrido-Cameán, Daniel
name: Oswald, Matthew C W
name: Bailey, David M D
name: Mukherjee, Amrita
name: Landgraf, Matthias
Publisher: name: Apollo - University of Cambridge Repository
Year: 2022
Subjects: Drosophila
Reactive oxygen species
Motoneuron
NADPH oxidase
Plasticity
Nox
Dual Oxidase
Aquaporin Genes

description: Neurons respond to changes in the levels of activity they experience in a variety of ways, including structural changes at pre- and postsynaptic terminals. An essential plasticity signal required for such activity-regulated structural adjustments are reactive oxygen species (ROS). To identify sources of activity-regulated ROS required for structural plasticity in vivo we used the Drosophila larval neuromuscular junction as a highly tractable experimental model system. For adjustments of presynaptic motor terminals, we found a requirement for both NADPH oxidases, Nox and dual oxidase (Duox), that are encoded in the Drosophila genome. This contrasts with the postsynaptic dendrites from which Nox is excluded. NADPH oxidases generate ROS to the extracellular space. Here, we show that two aquaporins, Bib and Drip, are necessary ROS conduits in the presynaptic motoneuron for activity regulated, NADPH oxidase dependent changes in presynaptic motoneuron terminal growth. Our data further suggest that different aspects of neuronal activity-regulated structural changes might be regulated by different ROS sources: changes in bouton number require both NADPH oxidases, while activity-regulated changes in the number of active zones might be modulated by other sources of ROS. Overall, our results show NADPH oxidases as important enzymes for mediating activity-regulated plasticity adjustments in neurons.
Chirality-induced one-way quantum steering between two waveguide-mediated ferrimagnetic microspheres
Creators: name: Zhan, Huiping
name: Sun, Lihui
name: Tan, Huatang
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: One-way quantum steering is of importance for quantum technologies, such as secure quantum teleportation. In this paper, we study the generation of one-way quantum steering between two distant yttrium iron garnet (YIG) microspheres in chiral waveguide electromagonics. We consider that the magnon mode with the Kerr nonlinearity in each YIG sphere is chirally coupled to left- and right-propagating guided photons in the waveguide. We find that quantum steering between the magnon modes is absent with non-chirality but is present merely in the form of one way (i.e., one-way steering) when the chirality occurs. The maximal achievable steering is obviously improved as the chirality degree increases. We further find that when the waveguide's outputs are subjected to continuous homodyne detection, the steering can be considerably enhanced and asymmetric steering with strong entanglement can also be achieved by tuning the chirality. Our study shows that chirality can be explored to effectively realize one-way quantum steering. Compared to other studies on achieving asymmetric steering via controlling intrinsic dissipation, e.g. cavity loss rates, our scheme merely depends on the chirality enabled via positioning the micromagnets in the waveguide and is continuously adjustable and experimentally more feasible.
description: 12 pages, 8 figures
Cylindrical contact homology and topological entropy
Creators: name: Alves, Marcelo R. R.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Dynamical Systems (math.DS)
subject: Symplectic Geometry (math.SG)
subject: FOS: Mathematics
subject: 53D42, 37J05

description: We establish a relation between the growth of the cylindrical contact homology of a contact manifold and the topological entropy of Reeb flows on this manifold. We show that if a contact manifold $(M,ξ)$ admits a hypertight contact form $λ_0$ for which the cylindrical contact homology has exponential homotopical growth rate, then the Reeb flow of every contact form on $(M,ξ)$ has positive topological entropy. Using this result, we provide numerous new examples of contact 3-manifolds on which every Reeb flow has positive topological entropy.
description: 42 pages, 2 figures. Exposition improved. Comments are welcome!
Improving the quality of generative models through Smirnov transformation
Creators: name: González-Prieto, Ángel
name: Mozo, Alberto
name: Gómez-Canaval, Sandra
name: Talavera, Edgar
Publisher: name: arXiv
Year: 2021
Subjects: subject: Machine Learning (cs.LG)
subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences
subject: I.2.m

description: Solving the convergence issues of Generative Adversarial Networks (GANs) is one of the most outstanding problems in generative models. In this work, we propose a novel activation function to be used as output of the generator agent. This activation function is based on the Smirnov probabilistic transformation and it is specifically designed to improve the quality of the generated data. In sharp contrast with previous works, our activation function provides a more general approach that deals not only with the replication of categorical variables but with any type of data distribution (continuous or discrete). Moreover, our activation function is derivable and therefore, it can be seamlessly integrated in the backpropagation computations during the GAN training processes. To validate this approach, we evaluate our proposal against two different data sets: a) an artificially rendered data set containing a mixture of discrete and continuous variables, and b) a real data set of flow-based network traffic data containing both normal connections and cryptomining attacks. To evaluate the fidelity of the generated data, we analyze both their results in terms of quality measures of statistical nature and also regarding the use of these synthetic data to feed a nested machine learning-based classifier. The experimental results evince a clear outperformance of the GAN network tuned with this new activation function with respect to both a naïve mean-based generator and a standard GAN. The quality of the data is so high that the generated data can fully substitute real data for training the nested classifier without a fall in the obtained accuracy. This result encourages the use of GANs to produce high-quality synthetic data that are applicable in scenarios in which data privacy must be guaranteed.
description: 28 pages, 16 Figures, 4 Tables
Donald Lynden-Bell Bibliography from Donald Lynden-Bell. 5 April 1935— 6 February 2018
Creators: name: Evans, Neil Wyn
Publisher: name: The Royal Society
Year: 2020
Subjects: Astrophysics

description: Donald Lynden-Bell's many contributions to astrophysics encompass general relativity, galactic dynamics, telescope design and observational astronomy. In the 1960s, his papers on stellar dynamics led to fundamental insights into the equilibria of elliptical galaxies, the growth of spiral patterns in disc galaxies and the stability of differentially rotating, self-gravitating flows. Donald introduced the ideas of 'violent relaxation' and 'the gravothermal catastrophe' in pioneering work on the thermodynamics of galaxies and negative heat capacities. He shared the inaugural Kavli Prize in Astrophysics in 2008 for his contributions to our understanding of quasars. His prediction that dead quasars or supermassive black holes may reside in the nuclei of nearby galaxies has been confirmed by multiple pieces of independent evidence. His work on accretion discs led to new insights into their workings, as well as the realization that the infrared excess in T Tauri stars was caused by protostellar discs around these young stars. He introduced the influential idea of monolithic collapse of a gas cloud as a formation mechanism for the Milky Way Galaxy. As this gave way to modern ideas of merging and accretion as drivers of galaxy formation, Donald was the first to realize the importance of tidal streams as measures of the past history and present-day gravity field of the Galaxy. Though primarily a theorist, Donald participated in one of the first observational programmes to measure the large-scale streaming of nearby galaxies. This led to the discovery of the 'Great Attractor'. The depth and versatility of his contributions mark Donald out as one of the most influential and pre-eminent astronomers of his day.
Succinct Description and Efficient Simulation of Non-Markovian Open Quantum Systems
Creators: name: Li, Xiantao
name: Wang, Chunhao
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Non-Markovian open quantum systems represent the most general dynamics when the quantum system is coupled with a bath environment. The quantum dynamics arising from many important applications are non-Markovian. Although for special cases, such as Hamiltonian evolution and Lindblad evolution, quantum simulation algorithms have been extensively studied, efficient quantum simulations for the dynamics of non-Markovian open quantum systems remain underexplored. The most immediate obstacle for studying such systems is the lack of a universal succinct description of their dynamics. In this work, we fulfill the gap of studying such dynamics by 1) providing a succinct representation of the dynamics of non-Markovian open quantum systems with quantifiable error, and 2) developing an efficient quantum algorithm for simulating such dynamics with cost $O(t\, \mathrm{polylog}(t/ε))$ for evolution time $t$ and precision $ε$. Our derivation of the succinct representation is based on stochastic Schrödinger equations, which could lead to new alternatives to deal with open quantum systems as well.
description: 39 pages, no figures. To appear in Communications in Mathematical Physics
On Vertically Global, Horizontally Local Models for Astrophysical Disks
Creators: name: McNally, Colin P.
name: Pessah, Martin E.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Disks with a barotropic equilibrium structure, for which the pressure is only a function of the density, rotate on cylinders in the presence of a gravitational potential, so that the angular frequency of such a disk is independent of height. Such disks with barotropic equilibria can be approximately modeled using the shearing box framework, representing a small disk volume with height-independent angular frequency. If the disk is in baroclinic equilibrium, the angular frequency does generally depend on height, and it is thus necessary to go beyond the standard shearing box approach. In this paper, we show that given a global disk model, it is possible to develop approximate models that are local in horizontal planes without an expansion in height with shearing-periodic boundary conditions. We refer to the resulting framework as the vertically global shearing box (VGSB). These models can be non-axisymmetric for globally barotropic equilibria but should be axisymmetric for globally baroclinic equilibria. We provide explicit equations for this VGSB which can be implemented in standard magnetohydrodynamic codes by generalizing the shearing-periodic boundary conditions to allow for a height-dependent angular frequency and shear rate. We also discuss the limitations that result from the radial approximations that are needed in order to impose height-dependent shearing periodic boundary conditions. We illustrate the potential of this framework by studying a vertical shear instability and examining the modes associated with the magnetorotational instability.
description: 24 pages, 8 figures, updated to match published version
General Boundary Formulation for $n$-Dimensional Classical Abelian Theory with Corners
Creators: name: Díaz-Marín, Homero G.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences
subject: 81T13, 70S15, 81T45 (Primary), 49S05 (Secondary)

description: We propose a general reduction procedure for classical field theories provided with abelian gauge symmetries in a Lagrangian setting. These ideas come from an axiomatic presentation of the general boundary formulation (GBF) of field theories, mostly inspired by topological quantum field theories (TQFT). We construct abelian Yang-Mills theories using this framework. We treat the case for space-time manifolds with smooth boundary components as well as the case of manifolds with corners. This treatment is the GBF analogue of extended TQFTs. The aim for developing this classical formalism is to accomplish, in a future work, geometric quantization at least for the abelian case.
Fidelity-optimized quantum state estimation
Creators: name: Kalev, Amir
name: Hen, Itay
Publisher: name: arXiv
Year: 2014
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We describe an optimized, self-correcting procedure for the Bayesian inference of pure quantum states. By analyzing the history of measurement outcomes at each step, the procedure returns the most likely pure state, as well as the optimal basis for the measurement that is to follow. The latter is chosen to maximize, on average, the fidelity of the most likely state after the measurement. We also consider a practical variant of this protocol, where the available measurement bases are restricted to certain limited sets of bases. We demonstrate the success of our method by considering in detail the single-qubit and two-qubit cases, and comparing the performance of our method against other existing methods.
description: 9 pages, 4 figures, 1 table
The Circular Unitary Ensemble and the Riemann zeta function: the microscopic landscape and a new approach to ratios
Creators: name: Chhaibi, Reda
name: Najnudel, Joseph
name: Nikeghbali, Ashkan
Publisher: name: arXiv
Year: 2014
Subjects: subject: Probability (math.PR)
subject: Mathematical Physics (math-ph)
subject: Number Theory (math.NT)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: We show in this paper that after proper scalings, the characteristic polynomial of a random unitary matrix converges almost surely to a random analytic function whose zeros, which are on the real line, form a determinantal point process with sine kernel. Our scaling is performed at the so-called "microscopic" level, that is we consider the characteristic polynomial at points which are of order $1/n$ distant. We prove this in the framework of virtual isometries to circumvent the fact that the rescaled characteristic polynomial does not even have a moment of order one, hence making the classical techniques of random matrix theory difficult to apply. The strong convergence results in this setup provide us with a new approach to ratios: we are able to solve open problems about the limiting distribution of ratios of characteristic polynomials evaluated at points of the form $\exp(2 i πα/n)$ and related objects (such as the logarithmic derivative). We also explicitly describe the dependence relation for the logarithm of the characteristic polynomial evaluated at several points on the microscopic scale. On the number theory side, inspired by the Keating-Snaith philosophy, we conjecture some new limit theorems for the value distribution of the Riemann zeta function on the critical line at the stochastic process level.
description: 71 pages; v1: New expanded version of arXiv:1403.7814 with new applications and a different point of view; v2: New approach to ratios formulas; v3: Added relevant references
WorldGen: A Large Scale Generative Simulator
Creators: name: Singh, Chahat Deep
name: Kumari, Riya
name: Fermüller, Cornelia
name: Sanket, Nitin J.
name: Aloimonos, Yiannis
Publisher: name: arXiv
Year: 2022
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Robotics (cs.RO)
subject: FOS: Computer and information sciences

description: In the era of deep learning, data is the critical determining factor in the performance of neural network models. Generating large datasets suffers from various difficulties such as scalability, cost efficiency and photorealism. To avoid expensive and strenuous dataset collection and annotations, researchers have inclined towards computer-generated datasets. Although, a lack of photorealism and a limited amount of computer-aided data, has bounded the accuracy of network predictions. To this end, we present WorldGen -- an open source framework to autonomously generate countless structured and unstructured 3D photorealistic scenes such as city view, object collection, and object fragmentation along with its rich ground truth annotation data. WorldGen being a generative model gives the user full access and control to features such as texture, object structure, motion, camera and lens properties for better generalizability by diminishing the data bias in the network. We demonstrate the effectiveness of WorldGen by presenting an evaluation on deep optical flow. We hope such a tool can open doors for future research in a myriad of domains related to robotics and computer vision by reducing manual labor and the cost of acquiring rich and high-quality data.
The influence of congenital corneal opacity on ERGs obtained using an abbreviated protocol
Creators: name: Liasis, Alkiviades
name: Franco, Elena
name: Eldib, Amgad
name: Handley, Sian
name: Scanga, Hannah L.
name: Nischal, Ken K.
Publisher: name: Taylor & Francis
Year: 2022
Subjects: subject: Space Science
subject: Medicine
subject: Neuroscience
subject: Physiology
subject: FOS: Biological sciences
subject: 69999 Biological Sciences not elsewhere classified
subject: Science Policy

description: Visual electrophysiology may be used to assess visual potential in infants with congenital corneal opacities (CCO). It is essential to recognize confounding effects from these opacities on the flash electroretinogram (ERG). ERGs were recorded in awake children employing skin electrodes placed at the lower eyelid crease, both referred to a midfrontal electrode (Fz). A hand-held stimulator was used to present a mixed rod-cone and a dim white stimulus. Recordings were carried out before and after penetrating keratoplasty (PK), when performed. Five infants under the age of 12 months with visually significant CCO were evaluated. In all cases, initial ERGs employing the mixed rod-cone stimulus showed well-defined a-wave with reduced amplitude b-wave. Reduction of stimulus intensity resulted in an increase in the b-wave and normalization of the b:a ratio from 1.1 (range 0.7 to 1.3) to 2.8 (range 1.5 to 4.3). In three cases who underwent PK, the postoperative ERGs recorded with a mixed rod-cone stimulus were normal in waveform shape with a mean b:a ratio of 2.0 (range 1.7 to 3.0). Selective reduction of the scotopic bright flash ERG b-wave is typically caused by retinal dysfunction that is post-phototransduction or inner retinal. In infants with CCO, scotopic ERGs to bright flashes can show a reduced b:a ratio that improves or normalizes either after PK or stimulus intensity reduction. The study highlights that media opacity can contribute to the generation of an ERG with reduced b-wave in the absence of inner retinal dysfunction.
A generating set for the palindromic Torelli group
Creators: name: Fullarton, Neil J.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Geometric Topology (math.GT)
subject: Group Theory (math.GR)
subject: FOS: Mathematics

description: A palindrome in a free group F_n is a word on some fixed free basis of F_n that reads the same backwards as forwards. The palindromic automorphism group ΠA_n of the free group F_n consists of automorphisms that take each member of some fixed free basis of F_n to a palindrome; the group ΠA_n has close connections with hyperelliptic mapping class groups, braid groups, congruence subgroups of GL(n,Z), and symmetric automorphisms of free groups. We obtain a generating set for the subgroup of ΠA_n consisting of those elements acting trivially on the abelianisation of F_n, the palindromic Torelli group PI_n. The group PI_n is a free group analogue of the hyperelliptic Torelli subgroup of the mapping class group of an oriented surface. We obtain our generating set by constructing a simplicial complex on which PI_n acts in a nice manner, adapting a proof of Day-Putman. The generating set leads to a finite presentation of the principal level 2 congruence subgroup of GL(n,Z).
Some results on Berge's conjecture and Begin-End conjecture
Creators: name: Freitas, Lucas Ismaily Bezerra
name: Lee, Orlando
Publisher: name: arXiv
Year: 2021
Subjects: subject: Combinatorics (math.CO)
subject: FOS: Mathematics

description: Let $D$ be a digraph. A subset $S$ of $V(D)$ is a stable set if every pair of vertices in $S$ is non-adjacent in $D$. A collection of disjoint paths $\mathcal{P}$ of $D$ is a path partition of $V(D)$, if every vertex in $V(D)$ is on a path of $\mathcal{P}$. We say that a stable set $S$ and a path partition $\mathcal{P}$ are orthogonal if each path of $P$ contains exactly one vertex of $S$. A digraph $D$ satisfies the $α$-property if for every maximum stable set $S$ of $D$, there exists a path partition $\mathcal{P}$ such that $S$ and $\mathcal{P}$ are orthogonal. A digraph $D$ is $α$-diperfect if every induced subdigraph of $D$ satisfies the $α$-property. In 1982, Claude Berge proposed a characterization of $α$-diperfect digraphs in terms of forbidden anti-directed odd cycles. In 2018, Sambinelli, Silva and Lee proposed a similar conjecture. A digraph $D$ satisfies the Begin-End-property or BE-property if for every maximum stable set $S$ of $D$, there exists a path partition $\mathcal{P}$ such that (i) $S$ and $\mathcal{P}$ are orthogonal and (ii) for each path $P \in \mathcal{P}$, either the start or the end of $P$ lies in $S$. A digraph $D$ is BE-diperfect if every induced subdigraph of $D$ satisfies the BE-property. Sambinelli, Silva and Lee proposed a characterization of BE-diperfect digraphs in terms of forbidden blocking odd cycles. In this paper, we show some structural results for $α$-diperfect and BE-diperfect digraphs. In particular, we show that in every minimal counterexample $D$ to both conjectures, the size of a maximum stable set is smaller than $\vert V(D)\vert /2$. As an application we use these results to prove both conjectures for arc-locally in-semicomplete and arc-locally out-semicomplete digraphs.
title: Horst Antes’ Kopffüßler
Creators: name: Rapp, Christof
Publisher: name: Center for Advanced Studies LMU
Year: 2020
Subjects: subject: 750 Paintings and paintings (museums)
subject: FOS: Art (arts, history of arts, performing arts, music)

description: In Zusammenarbeit mit dem Franz Marc Museum in Kochel stellt das Center for Advanced Studies der Ludwig-Maximilians-Universität München fast vierzig Werke des deutschen Künstlers Horst Antes (geb. 1936) aus.
ERIC A BARNARD - Bibliography from DONALD LYNDEN-BELL CBE. 5 April 1935— 6 February 2018
Creators: name: Evans, Neil Wyn
Publisher: name: The Royal Society
Year: 2020
Subjects: Astrophysics

description: Donald Lynden-Bell's many contributions to astrophysics encompass general relativity, galactic dynamics, telescope design and observational astronomy. In the 1960s, his papers on stellar dynamics led to fundamental insights into the equilibria of elliptical galaxies, the growth of spiral patterns in disc galaxies and the stability of differentially rotating, self-gravitating flows. Donald introduced the ideas of ‘violent relaxation’ and ‘the gravothermal catastrophe’ in pioneering work on the thermodynamics of galaxies and negative heat capacities. He shared the inaugural Kavli Prize in Astrophysics in 2008 for his contributions to our understanding of quasars. His prediction that dead quasars or supermassive black holes may reside in the nuclei of nearby galaxies has been confirmed by multiple pieces of independent evidence. His work on accretion discs led to new insights into their workings, as well as the realization that the infrared excess in T Tauri stars was caused by protostellar discs around these young stars. He introduced the influential idea of monolithic collapse of a gas cloud as a formation mechanism for the Milky Way Galaxy. As this gave way to modern ideas of merging and accretion as drivers of galaxy formation, Donald was the first to realize the importance of tidal streams as measures of the past history and present-day gravity field of the Galaxy. Though primarily a theorist, Donald participated in one of the first observational programmes to measure the large-scale streaming of nearby galaxies. This led to the discovery of the ‘Great Attractor’. The depth and versatility of his contributions mark Donald out as one of the most influential and pre-eminent astronomers of his day.
Learning from the Dark: Boosting Graph Convolutional Neural Networks with Diverse Negative Samples
Creators: name: Duan, Wei
name: Xuan, Junyu
name: Qiao, Maoying
name: Lu, Jie
Publisher: name: arXiv
Year: 2022
Subjects: subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: Graph Convolutional Neural Networks (GCNs) has been generally accepted to be an effective tool for node representations learning. An interesting way to understand GCNs is to think of them as a message passing mechanism where each node updates its representation by accepting information from its neighbours (also known as positive samples). However, beyond these neighbouring nodes, graphs have a large, dark, all-but forgotten world in which we find the non-neighbouring nodes (negative samples). In this paper, we show that this great dark world holds a substantial amount of information that might be useful for representation learning. Most specifically, it can provide negative information about the node representations. Our overall idea is to select appropriate negative samples for each node and incorporate the negative information contained in these samples into the representation updates. Moreover, we show that the process of selecting the negative samples is not trivial. Our theme therefore begins by describing the criteria for a good negative sample, followed by a determinantal point process algorithm for efficiently obtaining such samples. A GCN, boosted by diverse negative samples, then jointly considers the positive and negative information when passing messages. Experimental evaluations show that this idea not only improves the overall performance of standard representation learning but also significantly alleviates over-smoothing problems.
Particle momentum variation under interaction with wavepackets of finite spatial width
Creators: name: Bournelis, Theodoros
name: Kominis, Yannis
Publisher: name: arXiv
Year: 2022
Subjects: subject: Plasma Physics (physics.plasm-ph)
subject: Chaotic Dynamics (nlin.CD)
subject: FOS: Physical sciences

description: The single and collective particle interaction with spatially localized wavepackets is analytically and numerically studied. The role of the finite spatial width of the wavepacket on the momentum and energy variation of particles passing through the wavepacket is investigated. The range of validity of analytical results, based on a perturbative approach, is investigated and clearly defined. Strongly nonlinear effects are shown to qualitatively differentiate the collective particle dynamics, for larger interaction strengths. These effects are manifested through the complex dependency of averaged momentum variations on the initial particle momentum, as shown by dissecting a particle distribution in terms of partitioning the ensemble of particles with respect to their initial momentum. The results provide understanding on the relation between single and collective particle dynamics and the emerging of complexity for weak and strong particle interactions with localized wavepackets.
description: 21 pages, 9 figures, to appear in Physica Sripta
A Dynamic Model for Bus Arrival Time Estimation based on Spatial Patterns using Machine Learning
Creators: name: Ashwini, B. P.
name: Sumathi, R.
name: Sudhira, H. S.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Machine Learning (cs.LG)
subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences

description: The notion of smart cities is being adapted globally to provide a better quality of living. A smart city's smart mobility component focuses on providing smooth and safe commuting for its residents and promotes eco-friendly and sustainable alternatives such as public transit (bus). Among several smart applications, a system that provides up-to-the-minute information like bus arrival, travel duration, schedule, etc., improves the reliability of public transit services. Still, this application needs live information on traffic flow, accidents, events, and the location of the buses. Most cities lack the infrastructure to provide these data. In this context, a bus arrival prediction model is proposed for forecasting the arrival time using limited data sets. The location data of public transit buses and spatial characteristics are used for the study. One of the routes of Tumakuru city service, Tumakuru, India, is selected and divided into two spatial patterns: sections with intersections and sections without intersections. The machine learning model XGBoost is modeled for both spatial patterns individually. A model to dynamically predict bus arrival time is developed using the preceding trip information and the machine learning model to estimate the arrival time at a downstream bus stop. The performance of models is compared based on the R-squared values of the predictions made, and the proposed model established superior results. It is suggested to predict bus arrival in the study area. The proposed model can also be extended to other similar cities with limited traffic-related infrastructure.
The little sibling of the big rip singularity
Creators: name: Bouhmadi-Lopez, Mariam
name: Errahmani, Ahmed
name: Martin-Moruno, Prado
name: Ouali, Taoufik
name: Tavakoli, Yaser
Publisher: name: arXiv
Year: 2014
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We present a new cosmological event, which we named the little sibling of the big rip. This event is much smoother than the big rip singularity. When the little sibling of the big rip is reached, the Hubble rate and the scale factor blow up but the cosmic derivative of the Hubble rate does not. This abrupt event takes place at an infinite cosmic time where the scalar curvature explodes. We show that a doomsday á la little sibling of the big rip is compatible with an accelerating universe, indeed at present it would mimic perfectly a LCDM scenario. It turns out that eventhough the event seems to be harmless as it takes place in the infinite future, the bound structures in the universe would be unavoidably destroyed on a finite cosmic time from now. The model can be motivated by considering that the weak energy condition should not be abusibely violated in our Universe, and it could give us some hints about the status of recently formulated nonlinear energy conditions.
description: 20 pages, 4 figures, clarifications included
MERTK missense variants in three patients with retinitis pigmentosa
Creators: name: Poli, Federica E.
name: Yusuf, Imran H.
name: Clouston, Penny
name: Shanks, Morag
name: Whitfield, Jennifer
name: Issa, Peter Charbel
name: MacLaren, Robert E.
Publisher: name: Taylor & Francis
Year: 2022
Subjects: subject: Medicine
subject: Genetics
subject: FOS: Biological sciences
subject: Immunology
subject: FOS: Clinical medicine
subject: 69999 Biological Sciences not elsewhere classified
subject: 110309 Infectious Diseases
subject: FOS: Health sciences
subject: 60506 Virology
subject: Computational Biology

description: MERTK (MER proto-oncogene, tyrosine kinase) is a transmembrane protein essential in regulating photoreceptor outer segment phagocytosis. Biallelic mutations in MERTK cause retinal degeneration. Here we present the retinal phenotype of three patients with missense variants in MERTK. All patients underwent a full clinical examination, fundus photography, short-wavelength fundus autofluorescence and optical coherence tomography imaging. Two patients also underwent Goldmann visual field testing and electroretinography was undertaken for the third patient. Molecular genetic testing was undertaken using next generation or whole-exome sequencing with all variants confirmed by Sanger sequencing. The first patient was a 29-year-old female heterozygous for a missense variant (c.1133C>T, p.Thr378 Met) and a nonsense variant (c.1744_1751delinsT, p.Ile582Ter) in MERTK. The second patient was a 26-year-old male homozygous for a c.2163T>A, p.His721Gln variant in MERTK. The third patient was an 11-year-old female heterozygous for a deletion of exons 5–19 and a missense variant (c.1866 G>C, p.Lys622Asn) in MERTK. Reduced night vision was the initial symptom in all patients. Fundoscopy revealed typical signs of retinitis pigmentosa (RP) with early-onset macular atrophy. All three MERTK missense variants affect highly conserved residues within functional domains, have low population frequencies and are predicted to be pathogenic in silico. We report three missense variants in MERTK and present the associated phenotypic data, which are supportive of non-syndromic RP. MERTK is a promising candidate for viral-mediated gene replacement therapy. Moreover, one variant represents a single nucleotide transition, which is theoretically targetable with CRISPR-Cas9 base-editing.