bluuebunny/crossref_metadata_2025_split huggingface dataset:
Supergravity on a three-torus: quantum linearization instabilities with a supergroup
Authors: Higuchi Atsushi , Schmieding Lasse 
Published: May 2020

Abstract
It is well known that linearized gravity in spacetimes with compact Cauchy surfaces and continuous symmetries suffers from linearization instabilities: solutions to classical linearized gravity in such a spacetime must satisfy so-called linearization stability conditions (or constraints) for them to extend to solutions in the full non-linear theory. Moncrief investigated implications of these conditions in linearized quantum gravity in such background spacetimes and found that the quantum linearization stability constraints lead to the requirement that all physical states must be invariant under the symmetries generated by these constraints. He studied these constraints for linearized quantum gravity in flat spacetime with the spatial sections of toroidal topology in detail. Subsequently, his result was reproduced by the method of group-averaging. In this paper the quantum linearization stability conditions are studied for

N
=
1

simple supergravity in this spacetime. In addition to the linearization stability conditions corresponding to the spacetime symmetries, i.e. spacetime translations, there are also fermionic linearization stability conditions corresponding to the background supersymmetry. We construct all states satisfying these quantum linearization stability conditions, including the fermionic ones, and show that they are obtained by group-averaging over the supergroup of the global supersymmetry of this theory.
Stationary quantum entanglement between a massive mechanical membrane and a low frequency LC circuit
Authors: Li Jie , Gröblacher Simon 
Published: May 2020

Abstract
We study electro-mechanical entanglement in a system where a massive membrane is capacitively coupled to a low frequency LC resonator. In opto- and electro-mechanics, the entanglement between a megahertz (MHz) mechanical resonator and a gigahertz (GHz) microwave LC resonator has been widely and well explored, and recently experimentally demonstrated. Typically, coupling is realized through a radiation pressure-like interaction, and entanglement is generated by adopting an appropriate microwave drive. Through this approach it is however not evident how to create entanglement in the case where both the mechanical and LC oscillators are of low frequency, e.g., around 1 MHz. Here we provide an effective approach to entangling two low-frequency resonators by further coupling the membrane to an optical cavity. The cavity is strongly driven by a red-detuned laser, sequentially cooling the mechanical and electrical modes, which results in stationary electro-mechanical entanglement at experimentally achievable temperatures. The entanglement directly originates from the electro-mechanical coupling itself and due to its quantum nature will allow testing quantum theories at a more macroscopic scale than currently possible.
Emerging spectra characterization of catastrophic instabilities in complex systems
Authors: Chakraborti Anirban , Sharma Kiran , Pharasi Hirdesh K , Bakar K Shuvo , Das Sourish , Seligman Thomas H 
Published: May 2020

Abstract
Random matrix theory has been widely applied in physics, and even beyond physics. Here, we apply such tools to study catastrophic events, which occur rarely but cause devastating effects. It is important to understand the complexity of the underlying dynamics and signatures of catastrophic events in complex systems, such as the financial market or the environment. We choose the USA S&P-500 and Japanese Nikkei-225 financial markets, as well as the environmental ozone system in the USA. We study the evolution of the cross-correlation matrices and their eigen spectra over different short time-intervals or ‘epochs’. A slight non-linear distortion is applied to the correlation matrix computed for any epoch, leading to the emerging spectrum of eigenvalues, mainly around zero. The statistical properties of the emerging spectrum are intriguing—the smallest eigenvalues and the shape of the emerging spectrum (characterized by the spectral entropy) capture the system instability or criticality. Importantly, the smallest eigenvalue could also signal a precursor to a market catastrophe as well as a ‘market bubble’. We demonstrate in two paradigms the capacity of the emerging spectrum to understand the nature of instability; this is a new and robust feature that can be broadly applied to other physical or complex systems.
An ultracold heavy Rydberg system formed from ultra-long-range molecules bound in a stairwell potential
Authors: Hummel F , Schmelcher P , Ott H , Sadeghpour H R 
Published: May 2020

Abstract
We propose a scheme to realize a heavy Rydberg system (HRS), a bound pair of oppositely charged ions, from a gas of ultracold atoms. The intermediate step to achieve large internuclear separations is the creation of a unique class of ultra-long-range Rydberg molecules bound in a stairwell potential energy curve. Here, a ground-state atom is bound to a Rydberg atom in an oscillatory potential emerging due to attractive singlet p-wave electron scattering. The utility of our approach originates in the large electronic dipole transition element between the Rydberg and the ionic molecule, while the nuclear configuration of the ultracold gas is preserved. The Rabi coupling between the Rydberg molecule and the heavy Rydberg system is typically in the MHz range and the permanent electric dipole moments of the HRS can be as large as one kilo-Debye. We identify specific transitions which place the creation of the heavy Rydberg system within immediate reach of experimental realization.
Bose–Einstein-like condensation due to diffusivity edge under periodic confinement
Authors: Mahault Benoît , Golestanian Ramin 
Published: May 2020

Abstract
A generic class of scalar active matter, characterized at the mean field level by the diffusivity vanishing above some threshold density, was recently introduced [Golestanian R 2019 Phys. Rev. E
100 010601(R)]. In the presence of harmonic confinement, such ‘diffusivity edge’ was shown to lead to condensation in the ground state, with the associated transition exhibiting formal similarities with Bose–Einstein condensation (BEC). In this work, the effect of a diffusivity edge is addressed in a periodic potential in arbitrary dimensions, where the system exhibits coexistence between many condensates. Using a generalized thermodynamic description of the system, it is found that the overall phenomenology of BEC holds even for finite energy barriers separating each neighbouring pair of condensates. Shallow potentials are shown to quantitatively affect the transition, and introduce non-universality in the values of the scaling exponents.
Aluminum cluster size effects in the phase diagram of disordered Fe-Al alloys
Authors: Santos-Filho J. B. , Santos Sá A. V. , de Araujo Batista T. S. , Plascak J. A. 
Published: May 2020

Abstract
A spin-1/2 Ising model, with nearest-neighbor exchange and next-nearest-neighbor superexchange interactions, is proposed to describe the phase diagram of disordered Fe
p
-Al
q
(p + q = 1) alloys in the body centered cubic lattice. The size of the aluminum clusters have been taken into account in order to induce a superexchange interaction among the Fe atoms. Extensive Monte Carlo simulations have been employed by using a hybrid algorithm consisting of Metropolis spin flip and Wolff cluster algorithm, together with single histograms techniques. A good fit to the experimental phase diagram has been achieved, including the anomalous region for Al concentration in the range q ≤ 0.2.
Tailoring the orientation of perovskite crystals via adding two-dimensional polymorphs for perovskite solar cells
Authors: Guo Renjun , Buyruk Ali , Jiang Xinyu , Chen Wei , Reb Lennart K , Scheel Manuel A , Ameri Tayebeh , Müller-Buschbaum Peter 
Published: May 2020

Abstract
Organic-inorganic perovskite materials are attracting increasing attention for their use in high-performance solar cells due to their outstanding properties, such as long diffusion lengths, low recombination rate, and tunable bandgap. Finding an effective method of defect passivation is thought to be a promising route for improvements toward narrowing the distribution of the power conversion efficiency (PCE) values, given by the spread in the PCE over different devices fabricated under identical conditions, for easier commercialization. In this work, we add 2‐(4‐fluoroph-enyl)ethyl ammonium iodide (p-f-PEAI) into the bulk of a mixed cation lead halide perovskite (CH3NH3PbBr3)0.15(HC(NH2)2PbI3)0.85 thin film. We investigate the influence of different p-f-PEAI concentrations on the optical properties, morphology, crystal orientation, charge carrier dynamics, and device performance. We observe that introducing the proper amount of p-f-PEAI changes the preferential orientation of the perovskite crystals, promotes the strength of the crystal textures, and suppresses non-radiative charge recombination. Thus, we obtain a narrower distribution of the PCE of perovskite solar cells (PSCs) without sacrificing the PCE values reached. This is an important step toward better reproducibility to realize the commercialization of PSCs.
Shedding light on photosynthesis in carnivorous plants. A commentary on: ‘Nepenthes × ventrata photosynthesis under different nutrient applications’
Authors: Thorogood Chris , Bauer Ulrike 
Published: May 2020

This article comments on:Sebastià Capó-Bauçà, Marcel Font-Carrascosa, Miquel Ribas-Carbó, Andrej Pavlovč and Jeroni Galmés, Biochemical and mesophyll diffusional limits to photosynthesis are determined by prey and root nutrient uptake in the carnivorous pitcher plant Nepenthes × ventrata, Annals of Botany, Volume 126, Issue 1, 29 June 2020, Pages 25–37, https://doi.org/10.1093/aob/mcaa041.
Out in the open: behavior’s effect on predation risk and thermoregulation by aposematic caterpillars
Authors: Nielsen Matthew E , Mappes Johanna 
Published: May 2020

AbstractWarning coloration should be under strong stabilizing selection but often displays considerable intraspecific variation. Opposing selection on color by predators and temperature is one potential explanation for this seeming paradox. Despite the importance of behavior for both predator avoidance and thermoregulation, its role in mediating selection by predators and temperature on warning coloration has received little attention. Wood tiger moth caterpillars, Arctia plantaginis, have aposematic coloration, an orange patch on the black body. The size of the orange patch varies considerably: individuals with larger patches are safer from predators, but having a small patch is beneficial in cool environments. We investigated microhabitat preference by these caterpillars and how it interacted with their coloration. We expected caterpillar behavior to reflect a balance between spending time exposed to maximize basking and spending time concealed to avoid detection by predators. Instead, we found that caterpillars preferred exposed locations regardless of their coloration. Whether caterpillars were exposed or concealed had a strong effect on both temperature and predation risk, but caterpillars in exposed locations were both much warmer and less likely to be attacked by a bird predator (great tits, Parus major). This shared optimum may explain why we observed so little variation in caterpillar behavior and demonstrates the important effects of behavior on multiple functions of coloration.
Socially foraging bats discriminate between group members based on search-phase echolocation calls
Authors: Kohles Jenna E , Carter Gerald G , Page Rachel A , Dechmann Dina K N 
Published: May 2020

Abstract
Animals have evolved diverse strategies to use social information for increasing foraging success and efficiency. Echolocating bats, for example, can eavesdrop on bats foraging nearby because they shift from search-phase calls to feeding buzzes when they detect prey. Feeding buzzes can directly convey information about prey presence, but it is unknown whether search-phase calls also convey social information. Here, we investigated whether search-phase echolocation calls, distinct calls produced by some bat species to scan large open areas for prey, can additionally convey individual identity. We tested this in Molossus molossus, a neotropical insectivorous bat that forages with group members, presumably to find ephemeral insect swarms more efficiently. We caught M. molossus from six different social groups and recorded their search-phase calls during a standardized release procedure, then recaptured and tested 19 marked bats with habituation–dishabituation playback experiments. We showed that they can discriminate between group members based on search-phase calls, and our statistical analysis of call parameters supported the presence of individual signatures in search-phase calls. Individual discrimination is a prerequisite of individual recognition, which may allow M. molossus to maintain contact with group members while foraging without using specialized signals for communication.
FastTargetPred: a program enabling the fast prediction of putative protein targets for input chemical databases
Authors: Chaput Ludovic , Guillaume Valentin , Singh Natesh , Deprez Benoit , Villoutreix Bruno O 
Published: May 2020

Abstract

Summary
Several web-based tools predict the putative targets of a small molecule query compound by similarity to molecules with known bioactivity data using molecular fingerprints. In numerous situations, it would however be valuable to be able to run such computations on a local computer. We present FastTargetPred, a new program for the prediction of protein targets for small molecule queries. Structural similarity computations rely on a large collection of confirmed protein–ligand activities extracted from the curated ChEMBL 25 database. The program allows to annotate an input chemical library of ∼100k compounds within a few hours on a simple personal computer.

Availability and implementation
FastTargetPred is written in Python 3 (≥3.7) and C languages. Python code depends only on the Python Standard Library. The program can be run on Linux, MacOS and Windows operating systems. Pre-compiled versions are available at https://github.com/ludovicchaput/FastTargetPred. FastTargetPred is licensed under the GNU GPLv3. The program calls some scripts from the free chemistry toolkit MayaChemTools.

Contact
bruno.villoutreix@inserm.fr

Supplementary information
Supplementary data are available at Bioinformatics online.
Key long-proboscid fly pollinator overlooked: morphological and molecular analyses reveal a new Prosoeca (Nemestrinidae) species
Authors: Theron Genevieve L , Grenier Florent , Anderson Bruce C , Ellis Allan G , Johnson Steven D , Midgley John M , van der Niet Timotheüs 
Published: May 2020

Abstract
Long-proboscid nemestrinid flies are keystone pollinators of dozens of Southern African plants and, consequently, their taxonomic status might have important consequences for insect and plant conservation. We focus on Prosoeca peringueyi, considered to be a single, morphologically variable species, upon which a guild of ~28 plants in the winter rainfall region depends for pollination. We quantified morphological variation and established whether it was associated with genetic variation within and among sites. Phylogenetic analyses of the mitochondrial COI gene revealed two well-supported clades. One clade contains long-proboscid individuals that conform morphologically to the holotype of P. peringueyi. The sister clade contains individuals that frequently occur sympatrically with P. peringueyi and have shorter proboscides, with additional diagnostic characters that set it apart from P. peringueyi. A haplotype analysis based on nuclear ribosomal 28S DNA sequences of a subset of individuals corroborated these results. Based on our results, we propose the recognition of two species: P. peringueyi and Prosoeca torquata sp. nov., which is described here. Future research is required to quantify the interaction networks of these two fly species and the plant guilds with which they interact, to facilitate conservation in the global biodiversity hotspot where they occur.
On testing marginal versus conditional independence
Authors: Guo F Richard , Richardson Thomas S 
Published: May 2020

SummaryWe consider testing marginal independence versus conditional independence in a trivariate Gaussian setting. The two models are nonnested, and their intersection is a union of two marginal independences. We consider two sequences of such models, one from each type of independence, that are closest to each other in the Kullback–Leibler sense as they approach the intersection. They become indistinguishable if the signal strength, as measured by the product of two correlation parameters, decreases faster than the standard parametric rate. Under local alternatives at such a rate, we show that the asymptotic distribution of the likelihood ratio depends on where and how the local alternatives approach the intersection. To deal with this nonuniformity, we study a class of envelope distributions by taking pointwise suprema over asymptotic cumulative distribution functions. We show that these envelope distributions are well behaved and lead to model selection procedures with rate-free uniform error guarantees and near-optimal power. To control the error even when the two models are indistinguishable, rather than insist on a dichotomous choice, the proposed procedure will choose either or both models.
Are Minorities Subjected to, or Insulated from, Racialized Policing in Majority–Minority Community Contexts?
Authors: Gaston Shytierra , Brunson Rod K , Grossman Leigh S 
Published: May 2020

AbstractRacial conflict theories suggest that racialized policing should wane in areas where people of colour are the majority and Whites, the minority. This article examines community-level predictors of racial/ethnic differences in drug arrests from 2011 to 2016 across 86 census tracts in Newark, NJ, a city where most officers and residents are persons of colour. We examine whether racial conflict indicators predict Black, White and Hispanic drug arrests, accounting for other factors. Findings indicate that racialized policing prevails within this majority–minority context. Officers tend to arrest Blacks in communities with greater White and Hispanic residents and Whites in predominantly Black areas. In contrast, Hispanic arrests are not attributable to racialized policing. We conclude with recommendations for future theoretical redevelopment.
The Dilemma Between the Freedom to Use and the Proscription against Appropriating Outer Space and Celestial Bodies
Authors: Zannoni Diego 
Published: May 2020

Abstract
Although a large-scale extraction of resources from outer space does not seem feasible yet, associated legal debates are already underway. Indeed, anticipating a race for space resources, some States are taking the lead in enacting legislation regulating future exploitation by their subjects. Sales of “extraterrestrial real estate” by private entities have been taking place for decades. This article addresses the topic of exploitation of space resources from an international law perspective—regardless of whether it will be firmly on the agenda tomorrow or in thirty years’ time. The crucial issue is to establish if, and eventually how, it is possible to conciliate the two principles at stake here: freedom to use outer space and celestial bodies, which arguably includes exploitation, and the impermissibility of their appropriation. It will be pointed out that, rather than proposing a comprehensive and rigid mechanism, the Outer Space Treaty and the Moon Agreement could represent a starting point, a proactive framework for achieving consensus among States and for seeking multilateral solutions for the exploitation of space resources.
Identifying and Quantifying Cannabinoids in Biological Matrices in the Medical and Legal Cannabis Era
Authors: Karschner Erin L , Swortwood-Gates Madeleine J , Huestis Marilyn A 
Published: May 2020

AbstractBackgroundCannabinoid analyses generally included, until recently, the primary psychoactive cannabis compound, Δ9-tetrahydrocannabinol (THC), and/or its inactive metabolite, 11-nor-9-carboxy-THC, in blood, plasma, and urine. Technological advances revolutionized the analyses of major and minor phytocannabinoids in diverse biological fluids and tissues. An extensive literature search was conducted in PubMed for articles on cannabinoid analyses from 2000 through 2019. References in acquired manuscripts were also searched for additional articles.ContentThis article summarizes analytical methodologies for identification and quantification of multiple phytocannabinoids (including THC, cannabidiol, cannabigerol, and cannabichromene) and their precursors and/or metabolites in blood, plasma, serum, urine, oral fluid, hair, breath, sweat, dried blood spots, postmortem matrices, breast milk, meconium, and umbilical cord since the year 2000. Tables of nearly 200 studies outline parameters including analytes, specimen volume, instrumentation, and limits of quantification. Important diagnostic and interpretative challenges of cannabinoid analyses are also described. Medicalization and legalization of cannabis and the 2018 Agricultural Improvement Act increased demand for cannabinoid analyses for therapeutic drug monitoring, emergency toxicology, workplace and pain-management drug testing programs, and clinical and forensic toxicology applications. This demand is expected to intensify in the near future, with advances in instrumentation performance, increasing LC-MS/MS availability in clinical and forensic toxicology laboratories, and the ever-expanding knowledge of the potential therapeutic use and toxicity of phytocannabinoids.SummaryCannabinoid analyses and data interpretation are complex; however, major and minor phytocannabinoid detection windows and expected concentration ranges in diverse biological matrices improve the interpretation of cannabinoid test results.