cssi/SciSciGPT-SciSciNet huggingface dataset:
Circular dichroism in non-chiral metal halide perovskites

We demonstrate theoretically that non-chiral perovskite layers can exhibit circular dichroism (CD) in the absence of a magnetic field and without chiral activation by chiral molecules. The effect is shown to be due to splitting of helical excitonic states which can form in structures of orthorhombic or lower symmetry that exhibit Rashba spin effects. The selective coupling of these helical exciton states to helical light is shown to give rise to circular dichroism. Polarization dependent absorption is shown to occur due to the combined effect of Rashba splitting, in-plane symmetry breaking, and the effect of the exciton momentum on its fine structure, which takes the form of Zeeman splitting in an effective magnetic field. This phenomenon, which can be considered as a manifestation of extrinsic chirality, results in significant CD with an anisotropy factor of up to 30% in orthorhombic perovskite layers under off-normal, top illumination conditions, raising the possibility of its observation in non-chiral perovskite structures.
Predictive model with analysis of the initial spread of COVID-19 in India.

Abstract Objective The Coronavirus Disease 2019 (COVID-19) has currently ravaged through the world, resulting in over thirteen million confirmed cases and over five hundred thousand deaths, a complete change in daily life as we know it, worldwide lockdowns, travel restrictions, as well as heightened hygiene measures and physical distancing. Being able to analyse and predict the spread of this epidemic-causing disease is hence of utmost importance now, especially as it would help in the reasoning behind important decisions drastically affecting countries and their people, as well as in ensuring efficient resource and utility management. However, the needs of the people and specific conditions of the spread are varying widely from country to country. Hence, this article has two fold objectives: (i) conduct an in-depth statistical analysis of COVID-19 affected patients in India, (ii) propose a mathematical model for the prediction of spread of COVID-19 cases in India. Materials and method There has been limited research in modeling and predicting the spread of COVID-19 in India, owing both to the ongoing nature of the pandemic and limited availability of data. Currently famous SIR and non-SIR based Gauss-error-function and Monte Carlo simulation models do not perform well in the context of COVID-19 spread in India. We propose a ‘change-factor’ or ‘rate-of-change’ based mathematical model to predict the spread of the pandemic in India, with data drawn from hundreds of sources. Results Average age of affected patients was found to be 38.54 years, with 66.76% males, and 33.24% females. Most patients were in the age range of 18–40 years. Optimal parameter values of the prediction model are identified (α = 1.35, N = 3 and T = 10) by extensive experiments. Over the entire course of time since the outbreak started in India, the model has been 90.36% accurate in predicting the total number of cases the next day, correctly predicting the range in 150 out of the 166 days looked at. Conclusion The proposed system showed an accuracy of 90.36% for prediction since the first COVID-19 case in India, and 96.67% accuracy over the month of April. Predicted number of cases for the next day is found to be a function of the numbers over the last 3 days, but with an ‘increase’ factor influenced by the last 10 days. It is noticed that males are affected more than females. It is also noticed that in India, the number of people in each age bucket is steadily decreasing, with the largest number of adults infected being the youngest ones—a departure from the world trend. The model is self-correcting as it improves its predictions every day, by incorporating the previous day's data into the trend-line for the following days. This model can thus be used dynamically not only to predict the spread of COVID-19 in India, but also to check the effect of various government measures in a short span of time after they are implemented.
Morphological and Phylogenetic Resolution of Diplodia corticola and D. quercivora, Emerging Canker Pathogens of Oak (Quercus spp.), in the United States.

In Mediterranean Europe and the United States, oak species (Quercus spp.) have been in various states of decline for the past several decades. Several insect pests and pathogens contribute to this ...
A Survey of Racks and Quandles: Some recent developments

This short survey contains some recent developments of the algebraic theory of racks and quandles. We report on some elements of representation theory of quandles and ring theoretic approach to qua...
Influences on Attitudes Regarding Potential COVID-19 Vaccination in the United States

The COVID-19 pandemic continues to ravage the world, with the United States being highly affected. A vaccine provides the best hope for a permanent solution to controlling the pandemic. However, to be effective, a vaccine must be accepted and used by a large majority of the population. The aim of this study was to understand the attitudes towards and obstacles facing vaccination with a potential COVID-19 vaccine. To measure these attitudes a survey was administered to 316 respondents across the United States by a survey corporation. Structural equation modeling was used to analyze the relationships of several factors with attitudes toward potential COVID-19 vaccination. Prior vaccine usage and attitudes predicted attitudes towards COVID-19 vaccination. Assessment of the severity of COVID-19 for the United States was also predictive. Approximately 68% of all respondents were supportive of being vaccinated for COVID-19, but side effects, efficacy and length of testing remained concerns. Longer testing, increased efficacy and development in the United States were significantly associated with increased vaccine acceptance. Messages promoting COVID-19 vaccination should seek to alleviate the concerns of those who are already vaccine-hesitant. Messaging directed at the benefits of vaccination for the United States as a country would address the second predictive factor. Enough time should be taken to allay concerns about both short- and long-term side effects before a vaccine is released.
Genetic, morphological, and niche variation in the widely hybridizing Rhus integrifolia-Rhus ovata species complex

Hybridization and introgression are common processes among numerous plant species that present both challenges and opportunities for studies of species delimitation, phylogenetics, taxonomy, and adaptation. Rhus integrifolia and R. ovata are two ecologically important shrubs native to the southwestern USA and Mexico, and are known to hybridize frequently, but the morphological, genetic, and ecological implications of hybridization in these species are poorly studied on a broad geographic scale. Analyses were conducted using leaf morphology, genetic variation of plastid and nuclear loci, and species distribution models for both species and their putative hybrid introgressants across 19 localities in California and Arizona, USA. These analyses revealed evidence for morphological and genetic distinction among localities comprising putative parental species, but a high degree of morpho-genetic intermediacy among localities with putative hybrids. Comparison of morphological and genetic population structure among localities revealed evidence for putative local adaptation or widespread phenotypic plasticity. Multiple regression models identified a weak but statistically significant negative association between leaf area and precipitation. Finally, species distribution modeling inferred northward range shifts over time, with both species predicted to occupy more coastal regions in the future, possibly increasing the frequency of hybridization among them. These findings underscore the importance of integrative assessment of multiple data sources in the study of hybridizing species and highlight the Rhus integrifolia-ovata complex as a powerful model for investigating the adaptive implications of hybridization.
Comparison of Constrained and Unconstrained Human Grasp Forces Using Fingernail Imaging and Visual Servoing

Fingernail imaging has been proven to be effective in prior works [1], [2] for estimating the 3D fingertip forces with a maximum RMS estimation error of 7%. In the current research, fingernail imaging is used to perform unconstrained grasp force measurement on multiple fingers to study human grasping. Moreover, two robotic arms with mounted cameras and a visual tracking system have been devised to keep the human fingers in the camera frame during the experiments. Experimental tests have been conducted for six human subjects under both constrained and unconstrained grasping conditions, and the results indicate a significant difference in force collaboration among the fingers between the two grasping conditions. Another interesting result according to the experiments is that in comparison to constrained grasping, unconstrained grasp forces are more evenly distributed over the fingers and there is less force variation (more steadiness) in each finger force. These results validate the importance of measuring grasp forces in an unconstrained manner in order to study how humans naturally grasp objects.
The Silver Fox Domestication Experiment

For the last sixty years, a team of Russian geneticists have been running one of the most important biology experiments of the 20th, and now 21st, century. Each year they have selected the calmest foxes—foxes that are most prosocial to humans—to mimic the early stages of domestication. After providing an overview of how the silver fox domestication study began, I will discuss: 1) work on social cognition in the domesticated silver foxes, 2) work on the molecular genetics of domestication in the silver foxes, including work on changes in allele frequencies and changes in gene expression patterns, 3) a new hypothesis for how selection on tameness leads to the domestication syndrome via changes in the number and migration patterns of neural crest cells very early on in development, and 4) how the silver fox domestication experiment has led to new hypotheses about self-domestication in primates, including humans.
Implementation of screening, brief intervention, and referral to treatment (SBIRT) by nurses on acute care units: A qualitative descriptive study.

Screening, Brief Intervention, and Referral to Treatment (SBIRT) is an evidence-based intervention for patients with substance use disorders, but this intervention is under-utilized. Little is know...
A synergism between dimethyl trisulfide and methyl thiolacetate in attracting carrion-frequenting beetles demonstrated by use of a chemically-supplemented minimal trap

Volatile organic compounds derived from microbes recruit insects to carrion, shaping community assembly and ecological succession. The importance of individual volatiles and interactions between volatiles are difficult to assess in the field because of (1) the myriad compounds from decomposing animals and (2) the likelihood that complex volatile blends are important for the final approach to carrion. On the assumption that searching carrion-frequenting beetles may use simpler cues to orient at a distance, we employed a chemically-supplemented minimal trap that uses test chemicals associated with active decay to attract from a distance and a minimal carrion bait (a small fresh mouse carcass) to induce trap entry. Traps supplemented with both methyl thiolacetate (MeSAc) and dimethyl trisulfide (DMTS) attracted greater numbers of beetles including adult silphids (Necrophila americana and Oiceoptoma noveboracense) and the histerid Euspilotus assimilis than the combined totals of DMTS-only and MeSAc-only traps, demonstrating a synergism. The attraction of larval Necrophila americana to traps left in the field for less than 24 h suggests that larvae move between carrion sources. The use of such species for forensic applications requires caution.
Social media and COVID-19: Can social distancing be quantified without measuring human movements?

The COVID-19 outbreak has posed significant threats to international health and the economy. In the absence of treatment for this virus, public health officials asked the public to practice social distancing to reduce the number of physical contacts. However, quantifying social distancing is a challenging task and current methods are based on human movements. We propose a time and cost-effective approach to measure how people practice social distancing. This study proposes a new method based on utilizing the frequency of hashtags supporting and encouraging social distancing for measuring social distancing. We have identified 18 related hashtags and tracked their trends between Jan and May 2020. Our evaluation results show that there is a strong correlation (p < .05) between our findings and the Google social distancing report.
Advanced age attenuates the antihyperalgesic effect of morphine and decreases μ-opioid receptor expression and binding in the rat midbrain periaqueductal gray in male and female rats.

Abstract The present study investigated the impact of advanced age on morphine modulation of persistent inflammatory pain in male and female rats. The impact of age, sex, and pain on μ-opioid receptor (MOR) expression and binding in the ventrolateral periaqueductal gray (vlPAG) was also examined using immunohistochemistry and receptor autoradiography. Intraplantar administration of complete Freund's adjuvant induced comparable levels of edema and hyperalgesia in adult (2–3 mos) and aged (16–18 mos) male and female rats. Morphine potency was highest in adult males, with a greater than two-fold increase in morphine EC50 observed in adult versus aged males (3.83 mg/kg vs. 10.16 mg/kg). Adult and aged female rats also exhibited significantly higher EC50 values (7.76 mg/kg and 8.74 mg/kg, respectively) than adult males. The upward shift in EC50 from adult to aged males was paralleled by a reduction in vlPAG MOR expression and binding. The observed age-related reductions in morphine potency and vlPAG MOR expression and binding have significant implications in pain management in the aged population.
Sparse Mixture of Local Experts for Efficient Speech Enhancement.

In this paper, we investigate a deep learning approach for speech denoising through an efficient ensemble of specialist neural networks. By splitting up the speech denoising task into non-overlapping subproblems and introducing a classifier, we are able to improve denoising performance while also reducing computational complexity. More specifically, the proposed model incorporates a gating network which assigns noisy speech signals to an appropriate specialist network based on either speech degradation level or speaker gender. In our experiments, a baseline recurrent network is compared against an ensemble of similarly-designed smaller recurrent networks regulated by the auxiliary gating network. Using stochastically generated batches from a large noisy speech corpus, the proposed model learns to estimate a time-frequency masking matrix based on the magnitude spectrogram of an input mixture signal. Both baseline and specialist networks are trained to estimate the ideal ratio mask, while the gating network is trained to perform subproblem classification. Our findings demonstrate that a fine-tuned ensemble network is able to exceed the speech denoising capabilities of a generalist network, doing so with fewer model parameters.
Leading and Non-Leading Singularities in Gauge Theory Hard Scattering

Interest in perturbative methods for QCD and related gauge theories arises from the phenomenology of high energy scattering, and also from the study of weak-strong duality, as inspired by string theory. In the following, I’ll review some methods and techniques that have a long history but remain of continuing interest, along with a few recent advances. The talk starts with a perspective on the place of perturbation theory in an asymptotically free theory, goes on to recall ideas of factorization and resummation in pQCD, which leads to a review of one of its classic successes, so-called QT resummation. It concludes with applications of these same ideas to dimensionally-regulated amplitudes for the scattering of massless partons, which have been the subject of much recent work.
Quivers with potentials associated to triangulated surfaces

We attempt to relate two recent developments: cluster algebras associated to triangulations of surfaces by Fomin-Shapiro-Thurston, and quivers with potentials and their mutations introduced by Derksen-Weyman-Zelevinsky. To each ideal triangulation of a bordered surface with marked points we associate a quiver with potential, in such a way that whenever two ideal triangulations are related by a flip of an arc, the respective quivers with potentials are related by a mutation with respect to the flipped arc. We prove that if the surface has non-empty boundary, then the quivers with potentials associated to its triangulations are rigid and hence non-degenerate.
Certificate Transparency with Privacy

Certificate transparency (CT) is an elegant mechanism designed to detect when a certificate authority (CA) has issued a certificate incorrectly. Many CAs now support CT and it is being actively deployed in browsers. However, a number of privacy-related challenges remain. In this paper we propose practical solutions to two issues. First, we develop a mechanism that enables web browsers to audit a CT log without violating user privacy. Second, we extend CT to support non-public subdomains.
Exact second-order structure-function relationships

Equations that follow from the Navier–Stokes equation and incompressibility but with no other approximations are ‘exact’. Exact equations relating second- and third- order structure functions are studied, as is an exact incompressibility condition on the second-order velocity structure function. Opportunities for investigations using these equations are discussed. Precisely defined averaging operations are required to obtain exact averaged equations. Ensemble, temporal and spatial averages are all considered because they produce different statistical equations and because they apply to theoretical purposes, experiment and numerical simulation of turbulence. Particularly simple exact equations are obtained for the following cases: (i) the trace of the structure functions, (ii) DNS that has periodic boundary conditions, and (iii) an average over a sphere in r-space. Case (iii) introduces the average over orientations of r into the structure-function equations. The energy dissipation rate e appears in the exact trace equation without averaging, whereas in previous formulations e appears after averaging and use of local isotropy. The trace mitigates the effect of anisotropy in the equations, thereby revealing that the trace of the third-order structure function is expected to be superior for quantifying asymptotic scaling laws. The orientation average has the same property.
On matrix models of M5 branes

We compare the (0,2) theory of the single M5 brane decoupled from gravity in the lightcone with transverse R4, and a matrix nmodel description in terms of quatum mechanics on instanton moduli space. We give some tests of the Matrix model in the case of multi-5-branes on R4. We We extract constraints on the operator content of the field theory of the multi-5-brane system by analyzing the Matrix model. We also begin a study of compactifications of the (0,2) theory in this framework, arguing that, for large compactification scale, the (0,2) theory is described by super-quantum mechanics on appropriate instanton moduli spaces.
Interloper bias in future large-scale structure surveys

Next-generation spectroscopic surveys will map the large-scale structure of the observable universe, using emission line galaxies as tracers. While each survey will map the sky with a specific emission line, interloping emission lines can masquerade as the survey's intended emission line at different redshifts. Interloping lines from galaxies that are not removed can contaminate the power spectrum measurement, mixing correlations from various redshifts and diluting the true signal. We assess the potential for power spectrum contamination, finding that an interloper fraction worse than 0.2% could bias power spectrum measurements for future surveys by more than 10% of statistical errors, while also biasing power spectrum inferences. We also construct a formalism for predicting cosmological parameter measurement bias, demonstrating that a 0.15%–0.3% interloper fraction could bias the growth rate by more than 10% of the error, which can affect constraints on gravity from upcoming surveys. We use the COSMOS Mock Catalog (CMC), with the emission lines rescaled to better reproduce recent data, to predict potential interloper fractions for the Prime Focus Spectrograph (PFS) and the Wide-Field InfraRed Survey Telescope (WFIRST). We find that secondary line identification, or confirming galaxy redshifts by finding correlated emission lines, can remove interlopers for PFS. For WFIRST, we use the CMC to predict that the 0.2% target can be reached for the WFIRST Hα survey, but sensitive optical and near-infrared photometry will be required. For the WFIRST [O iii] survey, the predicted interloper fractions reach several percent and their effects will have to be estimated and removed statistically (e.g., with deep training samples). These results are optimistic as the CMC does not capture the full set of correlations of galaxy properties in the real Universe, and they do not include blending effects. Mitigating interloper contamination will be crucial to the next generation of emission line surveys.
Tensorization of the strong data processing inequality for quantum chi-square divergences

It is well-known that any quantum channel $\mathcal{E}$ satisfies the data processing inequality (DPI), with respect to various divergences, e.g., quantum $\chi^2_{\kappa}$divergences and quantum relative entropy. More specifically, the data processing inequality states that the divergence between two arbitrary quantum states $\rho$ and $\sigma$ does not increase under the action of any quantum channel $\mathcal{E}$. For a fixed channel $\mathcal{E}$ and a state $\sigma$, the divergence between output states $\mathcal{E}(\rho)$ and $\mathcal{E}(\sigma)$ might be strictly smaller than the divergence between input states $\rho$ and $\sigma$, which is characterized by the strong data processing inequality (SDPI). Among various input states $\rho$, the largest value of the rate of contraction is known as the SDPI constant. An important and widely studied property for classical channels is that SDPI constants tensorize. In this paper, we extend the tensorization property to the quantum regime: we establish the tensorization of SDPIs for the quantum $\chi^2_{\kappa_{1/2}}$ divergence for arbitrary quantum channels and also for a family of $\chi^2_{\kappa}$ divergences (with $\kappa \ge \kappa_{1/2}$) for arbitrary quantum-classical channels.
Characterizing TES power noise for future single optical-phonon and infrared-photon detectors

In this letter, we present the performance of a 100 μm × 400 μm × 40 nm W Transition-Edge Sensor with a critical temperature of 40 mK. This device has a noise equivalent power of 1.5×10-18 W/Hz, in a bandwidth of 2.6 kHz, indicating a resolution for Dirac delta energy depositions of 40 ± 5 meV (rms). The performance demonstrated by this device is a critical step toward developing a O(100) meV threshold athermal phonon detector for low-mass dark matter searches.
On the energy landscape of the mixed even p-spin model

We investigate the energy landscape of the mixed even p-spin model with Ising spin configurations. We show that for any given energy level between zero and the maximal energy, with overwhelming probability there exist exponentially many distinct spin configurations such that their energies stay near this energy level. Furthermore, their magnetizations and overlaps are concentrated around some fixed constants. In particular, at the level of maximal energy, we prove that the Hamiltonian exhibits exponentially many orthogonal peaks. This improves the results of Chatterjee (Disorder chaos and multiple valleys in spin glasses, 2009) and Ding et al. (Ann Probab 43(6):3468–3493, 2015), where the former established a logarithmic size of the number of the orthogonal peaks, while the latter proved a polynomial size. Our second main result obtains disorder chaos at zero temperature and at any external field. As a byproduct, this implies that the fluctuation of the maximal energy is superconcentrated when the external field vanishes and obeys a Gaussian limit law when the external field is present.
Spectral isolation of naturally reductive metrics on simple Lie groups

We show that within the class of left-invariant naturally reductive metrics $${\mathcal{M}_{{\rm Nat}}(G)}$$ on a compact simple Lie group G, every metric is spectrally isolated. We also observe that any collection of isospectral compact symmetric spaces is finite; this follows from a somewhat stronger statement involving only a finite part of the spectrum.
A Diphoton Resonance from Bulk RS

Recent LHC data hinted at a 750 GeV mass resonance that decays into two photons. A significant feature of this resonance is that its decays to any other Standard Model particles would be too low to be detected so far. Such a state has a compelling explanation in terms of a scalar or a pseudoscalar that is strongly coupled to vector states charged under the Standard Model gauge groups. Such a scenario is readily accommodated in bulk RS with a scalar localized in the bulk away from but close to the Higgs. Turning this around, we argue that a good way to find the elusive bulk RS model might be the search for a resonance with prominent couplings to gauge bosons.
HYPERBOLIC GROUPS WHICH FIBER IN INFINITELY MANY WAYS

We construct examples of free-by-cyclic hyperbolic groups which ber in innitely many ways over Z. The construction involves adding a specialized square 2-cell to a non-positively curved, squared 2-complex dened by labeled ori- ented graphs. The fundamental groups of the resulting complexes are hyperbolic, free-by-cyclic and can be mapped onto Z in innitely many ways.
A proof of the instability of AdS for the Einstein-null dust system with an inner mirror

In 2006, Dafermos and Holzegel formulated the so-called AdS instability conjecture, stating that there exist arbitrarily small perturbations to AdS initial data which, under evolution by the Einstein vacuum equations for Λ 0 and study the evolution of this system on the exterior domain {r≥r0}. The structure of the maximal development and the Cauchy stability properties of general initial data in this setting are studied in our companion paper (2017, arXiv: 1704.08685). The statement of the main theorem is as follows: We construct a family of mirror radii r0𝜀>0 and initial data 𝒮𝜀, 𝜀∈(0,1], converging, as 𝜀→0, to the AdS initial data 𝒮0 in a suitable norm, such that, for any 𝜀∈(0,1], the maximal development (ℳ𝜀,g𝜀) of 𝒮𝜀 contains a black hole region. Our proof is based on purely physical space arguments and involves the arrangement of the null dust into a large number of beams which are successively reflected off {r=r0𝜀} and ℐ, in a configuration that forces the energy of a certain beam to increase after each successive pair of reflections. As 𝜀→0, the number of reflections before a black hole is formed necessarily goes to +∞. We expect that this instability mechanism can be applied to the case of more general matter fields.
An Efficient Adversarial Attack for Tree Ensembles

We study the problem of efficient adversarial attacks on tree based ensembles such as gradient boosting decision trees (GBDTs) and random forests (RFs). Since these models are non-continuous step functions and gradient does not exist, most existing efficient adversarial attacks are not applicable. Although decision-based black-box attacks can be applied, they cannot utilize the special structure of trees. In our work, we transform the attack problem into a discrete search problem specially designed for tree ensembles, where the goal is to find a valid "leaf tuple" that leads to mis-classification while having the shortest distance to the original input. With this formulation, we show that a simple yet effective greedy algorithm can be applied to iteratively optimize the adversarial example by moving the leaf tuple to its neighborhood within hamming distance 1. Experimental results on several large GBDT and RF models with up to hundreds of trees demonstrate that our method can be thousands of times faster than the previous mixed-integer linear programming (MILP) based approach, while also providing smaller (better) adversarial examples than decision-based black-box attacks on general $\ell_p$ ($p=1, 2, \infty$) norm perturbations. Our code is available at this https URL.
Slicing the Torus: Obscuring Structures in Quasars

Quasars and Active Galactic Nuclei (AGNs) are often obscured by dust and gas. It is normally assumed that the obscuration occurs in an oblate obscuring torus, that begins at the radius at which the most refractive dust can remain solid. The most famous form of this torus is a donut-shaped region of molecular gas with a large scale-height. While this model is elegant and accounts for many phenomena at once, it does not hold up to detailed tests. Instead the obscuration in AGNs must occur on a wide range of scales and be due to a minimum of three physically distinct absorbers. Slicing the torus into these three regions will allow interesting physics of the AGN to be extracted.
A paucity of bulk entangling surfaces: AdS wormholes with de Sitter interiors

We study and construct spacetimes, dubbed planar AdS–dS-wormholes, satisfying the null energy condition and having two asymptotically AdS boundaries connected through a (non-traversable) inflating wormhole. As for other wormholes, it is natural to expect dual descriptions in terms of two disconnected conformal field theories (CFTs) in appropriate entangled states. But for our cases, certain expected bulk entangling surfaces used by the Hubeny–Rangamani–Takayanagi (HRT) prescription to compute CFT entropy do not exist. In particular, no real codimension-2 extremal surface can run from one end of the wormhole to the other. According to HRT, the mutual information between any two finite-sized subregions (one in each CFT) must then vanish at leading order in large N—though the leading-order mutual information per unit area between the two CFTs taken as wholes may be nonzero. Some planar AdS–dS-wormholes also fail to have plane-symmetric surfaces that would compute the total entropy of either CFT. We suggest this to remain true of less-symmetric surfaces so that the HRT entropy is ill-defined and some modified prescription is required. It may be possible to simply extend HRT or the closely-related maximin construction by a limiting procedure, though complex extremal surfaces could also play an important role.
Enhancement of Optical Response in Nanowires by Negative-Tone PMMA Lithography

The method of negative-tone polymethyl methacrylate (PMMA) electron-beam lithography is investigated to improve the performance of nanowire-based superconducting detectors. Using this approach, the superconducting nanowire single-photon detectors (SNSPDs) have been fabricated from 5-nm-thick NbN film sputtered at room temperature. To investigate the impact of this process, SNSPDs were prepared by positive-tone- and negative-tone-PMMA lithography, and their electrical and photodetection characteristics at 4.2 K were compared. The SNSPDs made by negative-tone-PMMA lithography show higher critical-current density and higher photon count rate at various wavelengths. Our results suggest a higher negative-tone-PMMA technology may be preferable to the standard positive-tone-PMMA lithography for this application.
Reduction of gravity-matter and dS gravity to hypersurface

The quantization scheme based on reduction of the physical states [11] is extended to two gravity-matter systems and pure dS gravity. For the gravity-matter systems we focus on quantization in a at background for simplicity, and renormalizability is established through conversion of matter degrees of freedom to the metric degrees of freedom. Quantization of pure dS gravity has several new novel features. It is noted that the infrared divergence does not arise in the present scheme of quantization. The lapse function constraint plays a crucial role.
Streamer-blowout Coronal Mass Ejections: Their Properties and Relation to the Coronal Magnetic Field Structure

We present a comprehensive analysis of a particular class of coronal mass ejection (CME) event called streamer-blowout CMEs (SBOs). The events are characterized by a gradual swelling of the overlying streamer, lasting hours to days, followed by a slow, wide CME, generally exhibiting a three-part structure, which leaves the streamer significantly depleted in its wake. We identify 909 SBO events in the LASCO/C2 observations between 1996 and 2015. The average blowout lasts for 40.5 hr, but the evacuation can take days for some events. The SBO CMEs are wider and more massive than the average CME. Their properties generally vary during and between solar cycles. Their minimum (maximum) monthly occurrence rate of one (six) events in cycle 23 has doubled in cycle 24—a probable manifestation of the weaker global fields in the current cycle. The locations of SBOs follow the tilt of the global dipole (but not from 2014 onward), do not correlate with sunspot numbers, and exhibit flux rope morphology at a much higher rate (61%) than regular CMEs (40%). We propose that these characteristics are consistent with SBOs arising from extended polarity inversion lines outside active regions (e.g., quiet Sun and polar crown filaments) through the release via reconnection of magnetic energy, likely accumulated via differential rotation.
Quantization of contact manifolds and thermodynamics

Abstract The physical variables of classical thermodynamics occur in conjugate pairs such as pressure/volume, entropy/temperature, chemical potential/particle number. Nevertheless, and unlike in classical mechanics, there are an odd number of such thermodynamic co-ordinates. We review the formulation of thermodynamics and geometrical optics in terms of contact geometry. The Lagrange bracket provides a generalization of canonical commutation relations. Then we explore the quantization of this algebra by analogy to the quantization of mechanics. The quantum contact algebra is associative, but the constant functions are not represented by multiples of the identity: a reflection of the classical fact that Lagrange brackets satisfy the Jacobi identity but not the Leibnitz identity for derivations. We verify that this ‘quantization’ describes correctly the passage from geometrical to wave optics as well. As an example, we work out the quantum contact geometry of odd-dimensional spheres.
Optimal Jammer Placement in UAV-assisted Relay Networks

We consider the relaying application of unmanned aerial vehicles (UAVs), in which UAVs are placed between two transceivers (TRs) to increase the throughput of the system. Instead of studying the placement of UAVs as pursued in existing literature, we focus on investigating the placement of a jammer or a major source of interference on the ground to effectively degrade the performance of the system, which is measured by the maximum achievable data rate of transmission between the TRs. We demonstrate that the optimal placement of the jammer is in general a non-convex optimization problem, for which obtaining the solution directly is intractable. Afterward, using the inherent characteristics of the signal-to-interference ratio (SIR) expressions, we propose a tractable approach to find the optimal position of the jammer. Based on the proposed approach, we investigate the optimal positioning of the jammer in both dual-hop and multi-hop UAV relaying settings. Numerical simulations are provided to evaluate the performance of our proposed method.
ACTIVE REGION TRANSITION REGION LOOP POPULATIONS AND THEIR RELATIONSHIP TO THE CORONA

The relationships among coronal loop structures at different temperatures are not settled. Previous studies have suggested that coronal loops in the core of an active region (AR) are not seen cooling through lower temperatures and therefore are steadily heated. If loops were cooling, the transition region would be an ideal temperature regime to look for a signature of their evolution. The Extreme-ultraviolet Imaging Spectrometer on Hinode provides monochromatic images of the solar transition region and corona at an unprecedented cadence and spatial resolution, making it an ideal instrument to shed light on this issue. Analysis of observations of AR 10978 taken in 2007 December 8-19 indicates that there are two dominant loop populations in the AR: (1) core multitemperature loops that undergo a continuous process of heating and cooling in the full observed temperature range 0.4-2.5 MK and even higher as shown by the X-Ray Telescope and (2) peripheral loops which evolve mostly in the temperature range 0.4-1.3 MK. Loops at transition region temperatures can reach heights of 150 Mm in the corona above the limb and develop downflows with velocities in the range of 39-105 km s–1.
Large Degree Asymptotics and the Reconstruction Threshold of the Asymmetric Binary Channels

In this paper, we consider a broadcasting process in which information is propagated from a given root node on a noisy tree network, and answer the question that whether the symbols at the nth level of the tree contain non-vanishing information of the root as n goes to infinity. Although the reconstruction problem on the tree has been studied in numerous contexts including information theory, mathematical genetics and statistical physics, the existing literatures with rigorous reconstruction thresholds established are very limited. In the remarkable work of Borgs et al. (in: 47th Annual IEEE Symposium on Foundations of Computer Science, FOCS, IEEE Computer Society, 2006), the exact threshold for the reconstruction problem for a binary asymmetric channel on the d-ary tree is establish, provided that the asymmetry is sufficiently small, which is the first exact reconstruction threshold obtained in roughly a decade. In this paper, by means of refined analyses of moment recursion on a weighted version of the magnetization, and concentration investigations, we rigorously give a complete answer to the question of how small it needs to be to establish the tightness of the reconstruction threshold and further determine its asymptotics of large degrees.
SYMMETRIC COLLECTIVE ATTACKS FOR THE EAVESDROPPING OF SYMMETRIC QUANTUM KEY DISTRIBUTION

We consider the collective eavesdropping of the BB84 and six-state protocols. Since these protocols are symmetric in the eigenstates of conjugate bases, we consider collective attacks having the same kind of symmetry. We then show how these symmetric collective attacks are sufficiently strong in order to minimize the Devetak–Winter rates. In fact, it is quite easy to construct simple examples able to reach the unconditionally secure key rates of these protocols.
Pontryagin classes of locally symmetric manifolds

In this note we compute low degree rational Pontryagin classes for every closed locally symmetric manifold of noncompact type. In particular, we answer the question: Which locally symmetric M have at least one nonzero Pontryagin class?
Tachyon potentials, star products and universality

We develop an efficient recursive method to evaluate the tachyon potential using the relevant universal subalgebra of the open string star algebra. This method, using off-shell versions of Virasoro Ward identities, avoids explicit computation of conformal transformations of operators and does not require a choice of background. We illustrate the procedure with a pedagogic computation of the level six tachyon potential in an arbitrary gauge, and the evaluation of a few simple star products. We give a background independent construction of the so-called identity of the star algebra, and show how it fits into family of string fields generating a commutative subalgebra.
Static and Dynamic Robust PCA and Matrix Completion: A Review

Principal component analysis (PCA) is one of the most widely used dimension reduction techniques. Robust PCA (RPCA) refers to the problem of PCA when the data may be corrupted by outliers. Recent work by Cands, Wright, Li, and Ma defined RPCA as a problem of decomposing a given data matrix into the sum of a low-rank matrix (true data) and a sparse matrix (outliers). The column space of the low-rank matrix then gives the PCA solution. This simple definition has led to a large amount of interesting new work on provably correct, fast, and practical solutions to RPCA. More recently, the dynamic (time-varying) version of the RPCA problem has been studied and a series of provably correct, fast, and memory-efficient tracking solutions have been proposed. Dynamic RPCA [or robust subspace tracking RST)] is the problem of tracking data lying in a (slowly) changing subspace, while being robust to sparse outliers. This paper provides an exhaustive review of the last decade of literature on RPCA and its dynamic counterpart (RST), along with describing their theoretical guarantees, discussing the pros and cons of various approaches, and providing empirical comparisons of performance and speed. A brief overview of the newer (lowrank) matrix completion (MC) literature is also provided. This refers to the problem of completing a low-rank matrix when only a subset of its entries are observed. It can be interpreted as a simpler special case of RPCA in which the indices of the outlier corrupted entries are known.
Metadata and Data Management for the Keck Observatory Archive

A collaboration between the W. M. Keck Observatory (WMKO) in Hawaii and the NASA Exoplanet Science Institute (NExScI) in California, the Keck Observatory Archive (KOA) was commissioned in 2004 to archive observing data from WMKO, which operates two classically scheduled 10 m ground-based telescopes. The observing data from Keck is not suitable for direct ingestion into the archive since the metadata contained in the original FITS headers lack the information necessary for proper archiving. Coupled with different standards among instrument builders and the heterogeneous nature of the data inherent in classical observing, in which observers have complete control of the instruments and their observations, the data pose a number of technical challenges for KOA. For example, it is often difficult to determine if an observation is a science target, a sky frame, or a sky flat. It is also necessary to assign the data to the correct owners and observing programs, which can be a challenge for time-domain and target-of-opportunity observations, or on split nights, during which two or more principle investigators share a given night. In addition, having uniform and adequate calibrations are important for the proper reduction of data. Therefore, KOA needs to distinguish science files from calibration files, identify the type of calibrations available, and associate the appropriate calibration files with each science frame. We describe the methodologies and tools that we have developed to successfully address these difficulties, adding content to the FITS headers and "retrofitting" the metadata in order to support archiving Keck data, especially those obtained before the archive was designed. With the expertise gained from having successfully archived observations taken with all eight currently active instruments at WMKO, we have developed lessons learned from handling this complex array of heterogeneous metadata that help ensure a smooth ingestion of data not only for current but also future instruments, as well as a better experience for the archive user.
Azimuthal anisotropies at high momentum from purely non-hydrodynamic transport

In the limit of short mean free path, relativistic kinetic theory gives rise to hydrodynamics through a systematically improvable gradient expansion. In the present work, a systematically improvable expansion in the opposite limit of large mean free path is considered, describing the dynamics of particles which are almost, but not quite, non-interacting. This non-hydrodynamic “eremitic” expansion does not break down for large gradients, and may be useful in situations where a hydrodynamic treatment is not applicable. As applications, azimuthal anisotropies at high transverse momenta in Pb + Pb and p + Pb collisions at $$\sqrt{s}=5.02$$ TeV are calculated from the first order eremitic expansion of kinetic theory in the relaxation time approximation.
A Bernstein problem for special Lagrangian equations

where λis are the eigenvalues of the Hessian D2u. Namely, any global convex solution to (1.1) in Rn must be a quadratic polynomial. Recall the classical result, any global convex solution in Rn to the Laplace equation u = λ1 + · · · + λn = c or the Monge-Ampere equation log det D2u = log λ1 + · · · + log λn = c must be quadratic. Equation (1.1) originates from special Lagrangian geometry [HL]. The (Lagrangian) graph (x, u (x)) ⊂ Rn ×Rn is called special when the argument of the complex number ( 1 +−1λ1 ) · · · (1 +√−1λn) is constant c or u satisfies (1.1), and it is special if and only if (x, u (x)) is a minimal surface in Rn × Rn [HL, Theorem 2.3, Proposition 2.17]. In terms of minimal surface, our result is the following
Doubling Inequality and Nodal Sets for Solutions of Bi-Laplace Equations

We investigate the doubling inequality and nodal sets for the solutions of bi-Laplace equations. A polynomial upper bound for the nodal sets of solutions and their gradient is obtained based on the recent development of nodal sets for Laplace eigenfunctions by Logunov. In addition, we derive an implicit upper bound for the nodal sets of solutions. We show two types of doubling inequalities for the solutions of bi-Laplace equations. As a consequence, the rate of vanishing is given for the solutions.
Few-shot Image Generation with Elastic Weight Consolidation

Few-shot image generation seeks to generate more data of a given domain, with only few available training examples. As it is unreasonable to expect to fully infer the distribution from just a few observations (e.g., emojis), we seek to leverage a large, related source domain as pretraining (e.g., human faces). Thus, we wish to preserve the diversity of the source domain, while adapting to the appearance of the target. We adapt a pretrained model, without introducing any additional parameters, to the few examples of the target domain. Crucially, we regularize the changes of the weights during this adaptation, in order to best preserve the information of the source dataset, while fitting the target. We demonstrate the effectiveness of our algorithm by generating high-quality results of different target domains, including those with extremely few examples (e.g., <10). We also analyze the performance of our method with respect to some important factors, such as the number of examples and the dissimilarity between the source and target domain.
Action spectroscopy of SrCl+ using an integrated ion trap time-of-flight mass spectrometer

The photodissociation cross-section of SrCl+ is measured in the spectral range of 36 000–46 000 cm−1 using a modular time-of-flight mass spectrometer (TOF-MS). By irradiating a sample of trapped SrCl+ molecular ions with a pulsed dye laser, X1Σ+ state molecular ions are electronically excited to the repulsive wall of the A1Π state, resulting in dissociation. Using the TOF-MS, the product fragments are detected and the photodissociation cross-section is determined for a broad range of photon energies. Detailed ab initio calculations of the SrCl+ molecular potentials and spectroscopic constants are also performed and are found to be in good agreement with experiment. The spectroscopic constants for SrCl+ are also compared to those of another alkaline earth halogen, BaCl+, in order to highlight structural differences between the two molecular ions. This work represents the first spectroscopy and ab initio calculations of SrCl+.