cssi/SciSciGPT-SciSciNet huggingface dataset:
Vehicle mobility on highly organic soils

Abstract Current political climates have generated a renewed interest in the northern regions of the world. These areas are known to have soft marshy peat, highly organic soils, and harsh winter climates. Current capabilities for vehicle mobility modeling on this terrain is limited and existing studies do not include contemporary military vehicles. This work presents mobility experiments of modern military vehicles at multiple field sites containing peat or highly organic soils that can be used to improve mobility modeling on these soils. Field experiments are being conducted during multiple seasons, including winter, spring, and summer. The vehicle traction, motion resistance, and hard surface rolling resistance of an instrumented High Mobility Multipurpose Wheeled Vehicle (HMMWV) and a Small Unit Support Vehicle (SUSV) were examined. The first is a common multi-purpose vehicle and the second is a vehicle designed to operate in these types of environments. This data set will provide the basis for model development and validation for vehicle mobility in highly organic soils.
Resilience of the rank of random matrices

Let M be an n × m matrix of independent Rademacher (±1) random variables. It is well known that if , then even after changing the sign of (1 – e)m/2 entries, M is still of full rank with high probability. Note that this is asymptotically best possible as one can easily make any two rows proportional with at most m/2 changes. Moreover, this theorem gives an asymptotic solution to a slightly weakened version of a conjecture made by Van Vu in [17].
μCB-seq: microfluidic cell barcoding and sequencing for high-resolution imaging and sequencing of single cells

Single-cell RNA sequencing (scRNA-seq) enables the investigation of complex biological processes in multicellular organisms with high resolution. However, many phenotypic features that are critical to understanding the functional role of cells in a heterogeneous tissue or organ are not directly encoded in the genome and therefore cannot be profiled with scRNA-seq. Quantitative optical microscopy has long been a powerful approach for characterizing diverse cellular phenotypes including cell morphology, protein localization, and chemical composition. Combining scRNA-seq with optical imaging has the potential to provide comprehensive single-cell analysis, allowing for functional integration of gene expression profiling and cell-state characterization. However, it is difficult to track single cells through both measurements; therefore, coupling current scRNA-seq protocols with optical measurements remains a challenge. Here, we report microfluidic cell barcoding and sequencing (μCB-seq), a microfluidic platform that combines high-resolution imaging and sequencing of single cells. μCB-seq is enabled by a novel fabrication method that preloads primers with known barcode sequences inside addressable reaction chambers of a microfluidic device. In addition to enabling multi-modal single-cell analysis, μCB-seq improves gene detection sensitivity, providing a scalable and accurate method for information-rich characterization of single cells.
High-Speed Femto-Joule per Bit Silicon-Conductive Oxide Nanocavity Modulator

By combining the large Purcell effect of photonic crystal nanocavity and the strong plasma dispersion effect of the transparent conductive oxides, ultra-compact silicon modulators with heterogeneously integrated indium-tin-oxide (ITO) can potentially achieve unprecedented energy efficiency. In this article, we report the first high-speed silicon nanocavity modulator driven by an ITO gate, achieving 1.94 GHz bandwidth. On-off-key modulation is measured up to 3 Gb/s with only 2 V voltage swing and 18.3 fJ/bit energy efficiency. In addition, we perform in-depth analysis of the energy efficiency and high frequency simulation of the nanocavity modulator, revealing the critical role played by the semiconductor conduction path and the overlapping factor between the accumulated free carriers and the cavity resonant mode. Based on our analysis, we propose a strategy to further improve the modulation bandwidth to 23.5 GHz by node-matched doping and reduce the energy consumption to the range of hundreds of atto-joule per bit.
Nielsen realization for infinite-type surfaces

Given a finite subgroup G of the mapping class group of a surface S, the Nielsen realization problem asks whether G can be realized as a finite group of homeomorphisms of S. In 1983, Kerckhoff showed that for S a finite-type surface, any finite subgroup G may be realized as a group of isometries of some hyperbolic metric on S. We extend Kerckhoff's result to orientable, infinite-type surfaces. As applications, we classify torsion elements in the mapping class group of the plane minus a Cantor set, and also show that topological groups containing sequences of torsion elements limiting to the identity do not embed continuously into the mapping class group of S. Finally, we show that compact subgroups of the mapping class group of S are finite, and locally compact subgroups are discrete.
Analysis of ZTE MRI application to sandstone and carbonate

Techniques such as micro-tomography (µCT) and nuclear magnetic resonance (NMR) methods have been used to characterize porous media for decades. Magnetic Resonance Imaging (MRI) offers direct visualization of pore architecture through a vast number of pulse sequences. In this work, we tested the MRI pulse sequence Zero Echo Time (ZTE) in the study of sandstone and carbonate. ZTE has been used previously to image highly porous geological material with relative success. In this research, ZTE was used to study porous systems tighter than those previously reported. We show that ZTE can resolve not only pore systems, but also a combination of fractures and pores simultaneously. Additionally, Pore Cluster Analysis (PCA), combined with ZTE, can be used to analyze connectivity of relatively large volume core plugs. By combining Time-Domain NMR pore-size analysis and PCA, we show that careful selection of resolution is necessary to understand transport in porous media.
Geno: A Developer Tool for Authoring Multimodal Interaction on Existing Web Applications

Supporting voice commands in applications presents significant benefits to users. However, adding such support to existing GUI-based web apps is effort-consuming with a high learning barrier, as shown in our formative study, due to the lack of unified support for creating multi-modal interfaces. We develop Geno---a developer tool for adding the voice input modality to existing web apps without requiring significate NLP expertise. Geno provides a unified workflow for developers to specify functionalities to support by voice (intents), create language models for detecting intents and the relevant information (parameters) from user utterances, and fulfill the intents by either programmatically invoking the corresponding functions or replaying GUI actions on the web app. Geno further supports references to GUI context in voice commands (e.g., "add this to the playlist"). In a study, developers with little NLP expertise were able to add the multi-modal support for two existing web apps using Geno.
3D printing novel PPE for response to COVID-19 related shortages

COVID-19 disruptions to the global supply chain has caused a shortage of personal protective equipment (PPE) at healthcare facilities world-wide. Traditional manufacturers are unable to fill the demand for equipment. Additive manufacturing has been able to help slacken the need by creating novel PPE. Over 8000 reusable filtered masks, over 10000 face shields, and testing equipment were created with the combined efforts of healthcare organizations, academic institutions, community maker organizations, and creative industry partners.
BETWEEN A ROCK AND A HARD PLACE: IDIOPATHIC CARDIAC OSSEOUS METAPLASIA COMPLICATING SEVERE MITRAL REGURGITATION

Idiopathic cardiac osseous metaplasia (ICOM) is a rare condition often presenting challenges in clinical management and generally associated with poor outcomes. A 77 year old female with prior admissions for heart failure presented for evaluation of symptomatic severe mitral regurgitation (MR). TTE
Anosov diffeomorphisms on Thurston geometric 4-manifolds

A long-standing conjecture asserts that any Anosov diffeomorphism of a closed manifold is finitely covered by a diffeomorphism which is topologically conjugate to a hyperbolic automorphism of a nilpotent manifold. In this paper, we show that any closed 4-manifold that carries a Thurston geometry and is not finitely covered by a product of two aspherical surfaces does not support (transitive) Anosov diffeomorphisms.
Measuring Secrecy by the Probability of a Successful Guess

The secrecy of a communication system in which both the legitimate receiver and an eavesdropper are allowed some distortion is investigated. The secrecy metric considered is the exponent of the probability that the eavesdropper estimates the source sequence successfully within an acceptable distortion level. The problem is first studied when the transmitter and the legitimate receiver do not share any key and the transmitter is not subject to a rate constraint, which corresponds to a stylized model of a side channel and reveals connections to source coding with side information. The setting is then generalized to include a shared secret key between the transmitter and the legitimate receiver and a rate constraint on the transmitter, which corresponds to the Shannon cipher system. A single-letter characterization of the highest achievable exponent is provided, and asymptotically optimal strategies for both the primary user and the eavesdropper are demonstrated.
Theory of random packings

We review a recently proposed theory of random packings. We describe the volume fluctuations in jammed matter through a volume function, amenable to analytical and numerical calculations. We combine an extended statistical mechanics approach ‘a la Edwards’ (where the role traditionally played by the energy and temperature in thermal systems is substituted by the volume and compactivity) with a constraint on mechanical stability imposed by the isostatic condition. We show how such approaches can bring results that can be compared to experiments and allow for an exploitation of the statistical mechanics framework. The key result is the use of a relation between the local Voronoi volume of the constituent grains and the number of neighbors in contact that permits a simple combination of the two approaches to develop a theory of random packings. We predict the density of random loose packing (RLP) and random close packing (RCP) in close agreement with experiments and develop a phase diagram of jammed matter that provides a unifying view of the disordered hard sphere packing problem and further shedding light on a diverse spectrum of data, including the RLP state. Theoretical results are well reproduced by numerical simulations that confirm the essential role played by friction in determining both the RLP and RCP limits. Finally we present an extended discussion on the existence of geometrical and mechanical coordination numbers and how to measure both quantities in experiments and computer simulations.
Investigating Novel Verb Learning in BERT: Selectional Preference Classes and Alternation-Based Syntactic Generalization.

Previous studies investigating the syntactic abilities of deep learning models have not targeted the relationship between the strength of the grammatical generalization and the amount of evidence to which the model is exposed during training. We address this issue by deploying a novel word-learning paradigm to test BERT’s few-shot learning capabilities for two aspects of English verbs: alternations and classes of selectional preferences. For the former, we fine-tune BERT on a single frame in a verbal-alternation pair and ask whether the model expects the novel verb to occur in its sister frame. For the latter, we fine-tune BERT on an incomplete selectional network of verbal objects and ask whether it expects unattested but plausible verb/object pairs. We find that BERT makes robust grammatical generalizations after just one or two instances of a novel word in fine-tuning. For the verbal alternation tests, we find that the model displays behavior that is consistent with a transitivity bias: verbs seen few times are expected to take direct objects, but verbs seen with direct objects are not expected to occur intransitively.
All Chern-Simons invariants of 4D, N = 1 gauged superform hierarchies

We give a geometric description of supersymmetric gravity/(non-)abelian p-form hierarchies in superspaces with 4D, N = 1 super-Poincare invariance. These hierarchies give rise to Chern-Simons-like invariants, such as those of the 5D, N = 1 graviphoton and the eleven-dimensional 3-form but also generalizations such as Green-Schwarz-like/BF -type couplings. Previous constructions based on prepotential superfields are reinterpreted in terms of p-forms in superspace thereby elucidating the underlying geometry. This vastly simplifies the calculations of superspace field-strengths, Bianchi identities, and Chern-Simons invariants. Using this, we prove the validity of a recursive formula for the conditions defining these actions for any such tensor hierarchy. Solving it at quadratic and cubic orders, we recover the known results for the BF -type and cubic Chern-Simons actions. As an application, we compute the quartic invariant ∼ AdAdAdA + . . . relevant, for example, to seven-dimensional supergravity compactifications.
At what chain length do unbranched alkanes prefer folded conformations

Short unbranched alkanes are known to prefer linear conformations, whereas long unbranched alkanes are folded. It is not known with certainty at what chain length the linear conformation is no longer the global minimum. To clarify this point, we use ab initio and density functional methods to compute the relative energies of the linear and hairpin alkane conformers for increasing chain lengths. Extensive electronic structure calculations are performed to obtain optimized geometries, harmonic frequencies, and accurate single point energies for the selected alkane conformers from octane through octadecane. Benchmark CCSD(T)/cc-pVTZ single point calculations are performed for chains through tetradecane, whereas approximate methods are required for the longer chains up to octadecane. Using frozen natural orbitals to unambiguously truncate the virtual orbital space, we are able to compute composite CCSD FNO(T) single point energies for all the chain lengths. This approximate composite method has significant co...
BMS invariance and the membrane paradigm

The Bondi-van der Burg-Metzner-Sachs (BMS) group is the asymptotic symmetry group of asymptotically flat spacetime. It is infinite dimensional and entails an infinite number of conservation laws. According to the black hole membrane paradigm, null infinity (in asymptotically flat spacetime) and black hole event horizons behave like fluid membranes. The fluid dynamics of the membrane is governed by an infinite set of symmetries and conservation laws. Our main result is to point out that the infinite set of symmetries and conserved charges of the BMS group and the membrane paradigm are the same. This relationship has several consequences. First, it sheds light on the physical interpretation of BMS conservation laws. Second, it generalizes the BMS conservation laws to arbitrary subregions of arbitrary null surfaces. Third, it clarifies the identification of the superrotation subgroup of the BMS group. We briefly comment on the black hole information problem.
Self-dual vector multiplet in 3D with gauged scale covariance

We present non-trivial interactions of N = 1 self-dual massive vector multiplet in three-dimensions, with gauged scale covariance. Our multiplets are a vector multiplet (Aμ,λ) and a gauge multiplet (Bμ,χ), where the latter is used for the gauging of the scale covariance of the former. Due to the absence of supergravity, this system has no lagrangian formulation, but has only a set of field equations. The gauge multiplet can also have Dirac-Born-Infeld type interactions, even in the presence of the massive self-dual vector multiplet. As a by-product, we also show that scale covariant couplings are possible for scalar multiplet. We also try a mechanism of spontaneous breaking of scale covariance by introducing a superpotential for scalar multiplets.
On the Extension of a TCFT to the Boundary of the Moduli Space

The purpose of this paper is to describe an analogue of a construction of Costello in the context of finite-dimensional differential graded Frobenius algebras which produces closed forms on the decorated moduli space of Riemann surfaces. We show that this construction extends to a certain natural compactification of the moduli space which is associated with the modular closure of the associative operad, due to the absence of ultra-violet divergences in the finite-dimensional case. We demonstrate that this construction is equivalent to the “dual construction” of Kontsevich.
ON THE sl(2) FOAM COHOMOLOGY COMPUTATIONS

We show how to use Bar-Natan's "divide and conquer" approach to computation to efficiently compute the universal sl(2) dotted foam cohomology groups, even for big knots and links. We also describe a purely topological version of the sl(2) foam theory, in the sense that no dots are needed on foams.
Resolutions of mesh algebras: periodicity and Calabi–Yau dimensions

A triangulated category $${(\mathcal{T},\Sigma)}$$ is said to be Calabi–Yau of dimension d if Σ d is a Serre functor. We determine which stable module categories of self-injective algebras Λ of finite type are Calabi–Yau and compute their Calabi–Yau dimensions, correcting errors in previous work. We first show that the Calabi–Yau property of mod-Λ can be detected in the minimal projective resolution of the stable Auslander algebra Γ of Λ, over its enveloping algebra. We then describe the beginning of such a minimal resolution for any mesh algebra of a stable translation quiver and apply covering theory to relate these minimal resolutions to those of the (generalized) preprojective algebras of Dynkin graphs. For representation-finite self-injective algebras of torsion order t = 1, we obtain a complete description of their stable Calabi–Yau properties, but only partial results for those algebras of torsion order t = 2. We also obtain some new information about the periods of the representation-finite self-injective algebras of torsion order t > 1. Finally, we describe how these questions can also be approached by realizing the stable categories of representation-finite self-injective algebras as orbit categories of the bounded derived categories of hereditary algebras, and illustrate this technique with several explicit computations that our previous methods left unsettled.
Tilt-invariant scanned oblique plane illumination microscopy for large-scale volumetric imaging

This Letter presents the first demonstration of multi-tile stitching for large scale 3D imaging in single objective light-sheet microscopy. We show undistorted 3D imaging spanning complete zebrafish larvae and over 1 mm3 volumes for thick mouse brain sections. We use remote galvo scanning for light-sheet creation and develop a processing pipeline for 3D tiling across different axes. With the improved one photon (1p) tilt-invariant scanned oblique plane illumination (SOPi, /sōpī/) microscope presented here, we demonstrate cellular resolution imaging at depths exceeding 330 μm in optically scattering mouse brain samples and dendritic imaging in more superficial layers.
Symbol-based successive cancellation list decoder for polar codes

Polar codes is promising because they can provably achieve the channel capacity while having an explicit construction method. Lots of work have been done for the bit-based decoding algorithm for polar codes. In this paper, generalized symbol-based successive cancellation (SC) and SC list decoding algorithms are discussed. A symbol-based recursive channel combination relationship is proposed to calculate the symbolbased channel transition probability. This proposed method needs less additions than the maximum-likelihood decoder used by the existing symbol-based polar decoding algorithm. In addition, a two-stage list pruning network is proposed to simplify the list pruning network for the symbol-based SC list decoding algorithm.
A Tight Relation between N/O Ratio and Galaxy Stellar Mass Can Explain the Evolution of Strong Emission Line Ratios with Redshift

The offset of high-redshift star-forming galaxies in the [O III]/Hβ versus [N II]/Hα (O3N2) diagram in comparison with the local star-forming galaxy sequence is now well established. The physical origin of the shift is the subject of some debate and has important implications for metallicity measurements based on strong lines at all redshifts. To investigate the origin of the O3N2 offset, we use a sample of ~100,000 star-forming galaxies from the Sloan Digital Sky Survey DR12 to understand how measurable galaxy physical properties (Σ_(SFR), ionization parameter, nitrogen-to-oxygen (N/O) ratio, and stellar mass) drive galaxy position in two key diagnostic diagrams: O3N2 and [O III]/Hβ versus [S II]/Hα (O3S2). At fixed [O III]/Hβ, galaxies close to the high-redshift locus in O3N2 have higher Σ_(SFR), stellar mass, and N/O ratio. We conclude that higher N/O ratios at fixed [O III]/Hβ are the proximate cause of the O3N2 shift. We also find a tight correspondence in the distributions of stellar mass and N/O in the diagnostic diagrams. This relation, spanning a range of galaxy evolutionary states, suggests that the N/O–M* relation is more fundamental than the relation between N/O and O/H. We argue that a more fundamental N/O–M* relation is well-motivated physically. Because the mass–metallicity relation evolves more rapidly with redshift than N/O–M*, the N/O ratios of high-redshift galaxies are elevated in comparison with local galaxies with the same gas-phase O/H. The O3N2 shift and elevated N/O ratios observed in high-redshift galaxies, therefore, come about as a natural consequence of the N/O–M* relation combined with the evolution of the mass–metallicity relation.
Estimating Long GRB Jet Opening Angles and Rest-Frame Energetics

We present a method to estimate the jet opening angles of long duration Gamma-Ray Bursts (GRBs) using the prompt gamma-ray energetics and an inversion of the Ghirlanda relation, which is a correlation between the timeintegrated peak energy of the GRB prompt spectrum and the collimationcorrected energy in gamma rays. The derived jet opening angles using this method and detailed assumptions match well with the corresponding inferred jet opening angles obtained when a break in the afterglow is observed. Furthermore, using a model of the predicted long GRB redshift probability distribution observable by the Fermi Gamma-ray Burst Monitor (GBM), we estimate the probability distributions for the jet opening angle and rest-frame energetics for a large sample of GBM GRBs for which the redshifts have not been observed. Previous studies have only used a handful of GRBs to estimate these properties due to the paucity of observed afterglow jet breaks, spectroscopic redshifts, and comprehensive prompt gamma-ray observations, and we potentially expand the number of GRBs that can be used in this analysis by more than an order of magnitude. In this analysis, we also present an inferred distribution of jet breaks which indicates that a large fraction of jet breaks are not observable with current instrumentation and observing strategies. We present simple parameterizations for the jet angle, energetics, and jet break distributions so that they may be used in future studies. Subject headings: gamma rays: bursts — methods: data analysis
Radio galaxies dominate the high-energy diffuse gamma-ray background

It has been suggested that unresolved radio galaxies and radio quasars (sometimes referred to as misaligned active galactic nuclei) could be responsible for a significant fraction of the observed diffuse gamma-ray background. In this study, we use the latest data from the Fermi Gamma-Ray Space Telescope to characterize the gamma-ray emission from a sample of 51 radio galaxies. In addition to those sources that had previously been detected using Fermi data, we report here the first statistically significant detection of gamma-ray emission from the radio galaxies 3C 212, 3C 411, and B3 0309+411B. Combining this information with the radio fluxes, radio luminosity function, and redshift distribution of this source class, we find that radio galaxies dominate the diffuse gamma-ray background, generating 77.2(+25.4)(-9.4)% of this emission at energies above ~1 GeV . We discuss the implications of this result and point out that it provides support for scenarios in which IceCube's high-energy astrophysical neutrinos also originate from the same population of radio galaxies.
X-Ray Sources with Periodic Variability in a Deep Chandra Image of the Galactic Center

We report the discovery of eight X-ray sources with periodic variability in 487 ks of observations of the Galactic center with Chandra. The sources are identified from a sample of 285 objects detected with 100-4200 net counts. Their periods range from 300 s to 4.5 hr, with amplitudes between 40% and 70% rms. They have luminosities of (1-5) × 1032 ergs s-1 (2-8 keV at 8 kpc). The spectra of seven of the eight sources are consistent with Γ ≈ 0 power laws absorbed by gas and dust with a column density equal to or higher than that toward the Galactic center (6 × 1022 cm-2). Four of these sources also exhibit emission lines near 6.7 keV from He-like Fe, with equivalent widths of 600-1000 eV. These properties are consistent with both magnetically accreting cataclysmic variables and wind-accreting neutron stars in high-mass X-ray binaries. The eighth source has an absorbing column of 5 × 1021 cm-2 that places it in the foreground. Its spectrum is consistent with either a Γ = 1.4 power law or kT = 25 keV bremsstrahlung emission. Its period-folded flux profile clearly identifies it as an eclipsing polar. We place an approximate upper limit of i' > 23 mag on the optical counterpart to this source using a 5 minute exposure obtained with the Magellan Instant Camera on the Clay telescope (Magellan II) at Las Campanas.
OBSERVATION OF A RIDGE CORRELATION STRUCTURE IN HIGH MULTIPLICITY PROTON–PROTON COLLISIONS: A BRIEF REVIEW

This paper briefly reviews the striking experimental observation of a ridge-like dihadron correlation structure in high multiplicity proton–proton collisions at the Large Hadron Collider (LHC). Recent progress of both experimental and theoretical efforts on understanding the physical origin of the novel effect is reviewed. Outlook on future direction of possible new studies is discussed.
Substance over Style: Document-Level Targeted Content Transfer

Existing language models excel at writing from scratch, but many real-world scenarios require rewriting an existing document to fit a set of constraints. Although sentence-level rewriting has been fairly well-studied, little work has addressed the challenge of rewriting an entire document coherently. In this work, we introduce the task of document-level targeted content transfer and address it in the recipe domain, with a recipe as the document and a dietary restriction (such as vegan or dairy-free) as the targeted constraint. We propose a novel model for this task based on the generative pre-trained language model (GPT-2) and train on a large number of roughly-aligned recipe pairs. Both automatic and human evaluations show that our model out-performs existing methods by generating coherent and diverse rewrites that obey the constraint while remaining close to the original document. Finally, we analyze our model’s rewrites to assess progress toward the goal of making language generation more attuned to constraints that are substantive rather than stylistic.
PROBING THE SOLAR ATMOSPHERE USING OSCILLATIONS OF INFRARED CO SPECTRAL LINES

Oscillations were observed across the whole solar disk using the Doppler shift and line center intensity of spectral lines from the CO molecule near 4666 nm with the National Solar Observatory's McMath/Pierce solar telescope. Power, coherence, and phase spectra were examined, and diagnostic diagrams reveal power ridges at the solar global mode frequencies to show that these oscillations are solar p-modes. The phase was used to determine the height of formation of the CO lines by comparison with the IR continuum intensity phase shifts as measured in Kopp et al.; we find that the CO line formation height varies from 425 km {mu} > 0.5. The velocity power spectra show that while the sum of the background and p-mode power increases with height in the solar atmosphere as seen in previous work, the power in the p-modes only (background subtracted) decreases with height. The CO line center intensity weakens in regions of stronger magnetic fields, as does the p-mode oscillation power. Across most of the solar surface the phase shift is larger than the expected value of 90{sup 0} for an adiabatic atmosphere.more » We fit the phase spectra at different disk positions with a simple atmospheric model to determine that the acoustic cutoff frequency is about 4.5 mHz with only small variations, but that the thermal relaxation frequency drops significantly from 2.7 to 0 mHz at these heights in the solar atmosphere.« less
Clinical XLNet: Modeling Sequential Clinical Notes and Predicting Prolonged Mechanical Ventilation

Clinical notes contain rich information, which is relatively unexploited in predictive modeling compared to structured data. In this work, we developed a new clinical text representation Clinical XLNet that leverages the temporal information of the sequence of the notes. We evaluated our models on prolonged mechanical ventilation prediction problem and our experiments demonstrated that Clinical XLNet outperforms the best baselines consistently. The models and scripts are made publicly available.
Acylindrical group actions on quasi-trees

A group G is acylindrically hyperbolic if it admits a non-elementary acylindrical action on a hyperbolic space. We prove that every acylindrically hyperbolic group G has a generating set X such that the corresponding Cayley graph Γ is a (non-elementary) quasi-tree and the action of G on Γ is acylindrical. Our proof utilizes the notions of hyperbolically embedded subgroups and projection complexes. As an application, we obtain some new results about hyperbolically embedded subgroups and quasi-convex subgroups of acylindrically hyperbolic groups.
RECENT KTEV RESULTS

Preliminary KTEV results are presented based on the 1997 data set, and include an improved measurement of ℜ(∊′/∊), CPT tests, and precise measurements of τS and Δm.
DIRAC'S CONTOUR REPRESENTATION FOR PARAPARTICLES

Dirac's contour representation is extended to para-Bose and para-Fermi systems by use of deformed algebra techniques. In this analytic representation, the action of the para-particle annihilation operator is equivalent to a deformed differentiation which encodes the statistics of the paraparticle. In the para-Fermi case, the derivative's ket-domain is degree p polynomial.
CONSTRAINING SOURCE REDSHIFT DISTRIBUTIONS WITH GRAVITATIONAL LENSING

We introduce a new method for constraining the redshift distribution of a set of galaxies, using weak gravitational lensing shear. Instead of using observed shears and redshifts to constrain cosmological parameters, we ask how well the shears around clusters can constrain the redshifts, assuming fixed cosmological parameters. This provides a check on photometric redshifts, independent of source spectral energy distribution properties and therefore free of confounding factors such as misidentification of spectral breaks. We find that {approx}40 massive ({sigma}{sub v} = 1200 km s{sup -1}) cluster lenses are sufficient to determine the fraction of sources in each of six coarse redshift bins to {approx}11%, given weak (20%) priors on the masses of the highest-redshift lenses, tight (5%) priors on the masses of the lowest-redshift lenses, and only modest (20%-50%) priors on calibration and evolution effects. Additional massive lenses drive down uncertainties as N{sub lens}{sup -1/2}, but the improvement slows as one is forced to use lenses further down the mass function. Future large surveys contain enough clusters to reach 1% precision in the bin fractions if the tight lens-mass priors can be maintained for large samples of lenses. In practice this will be difficult to achieve, but the method maymore » be valuable as a complement to other more precise methods because it is based on different physics and therefore has different systematic errors.« less
AmbigQA: Answering Ambiguous Open-domain Questions

Ambiguity is inherent to open-domain question answering; especially when exploring new topics, it can be difficult to ask questions that have a single, unambiguous answer. In this paper, we introduce AmbigQA, a new open-domain question answering task which involves finding every plausible answer, and then rewriting the question for each one to resolve the ambiguity. To study this task, we construct AmbigNQ, a dataset covering 14,042 questions from NQ-open, an existing open-domain QA benchmark. We find that over half of the questions in NQ-open are ambiguous, with diverse sources of ambiguity such as event and entity references. We also present strong baseline models for AmbigQA which we show benefit from weakly supervised learning that incorporates NQ-open, strongly suggesting our new task and data will support significant future research effort. Our data and baselines are available at https://nlp.cs.washington.edu/ambigqa.
D-branes, derived categories, and Grothendieck groups

Abstract In this paper we describe how Grothendieck groups of coherent sheaves and locally free sheaves can be used to describe type II D-branes, in the case that all D-branes are wrapped on complex varieties and all connections are holomorphic. Our proposal is in the same spirit as recent discussions of K-theory and D-branes; within the restricted class mentioned, Grothendieck groups encode a choice of connection on each D-brane world-volume, in addition to information about the C∞ bundles. We also point out that derived categories can also be used to give insight into D-brane constructions, and analyze how a Z 2 subset of the T-duality group acting on D-branes on tori can be understood in terms of a Fourier–Mukai transformation.
ON THE MINIMUM CORE MASS FOR GIANT PLANET FORMATION AT WIDE SEPARATIONS

In the core accretion hypothesis, giant planets form by gas accretion onto solid protoplanetary cores. The minimum (or critical) core mass to form a gas giant is typically quoted as 10 M ⊕. The actual value depends on several factors: the location in the protoplanetary disk, atmospheric opacity, and the accretion rate of solids. Motivated by ongoing direct imaging searches for giant planets, this study investigates core mass requirements in the outer disk. To determine the fastest allowed rates of gas accretion, we consider solid cores that no longer accrete planetesimals, as this would heat the gaseous envelope. Our spherical, two-layer atmospheric cooling model includes an inner convective region and an outer radiative zone that matches onto the disk. We determine the minimum core mass for a giant planet to form within a typical disk lifetime of 3 Myr. The minimum core mass declines with disk radius, from ~8.5 M ⊕ at 5 AU to ~3.5 M ⊕ at 100 AU, with standard interstellar grain opacities. Lower temperatures in the outer disk explain this trend, while variations in disk density are less influential. At all distances, a lower dust opacity or higher mean molecular weight reduces the critical core mass. Our non-self-gravitating, analytic cooling model reveals that self-gravity significantly affects early atmospheric evolution, starting when the atmosphere is only ~10% as massive as the core.
Detection of Potential Transit Signals in 17 Quarters of Kepler Data: Results of the Final Kepler Mission Transiting Planet Search (DR25)

We present results of the final Kepler Data Processing Pipeline search for transiting planet signals in the full 17-quarter primary mission data set. The search includes a total of 198,709 stellar targets, of which 112,046 were observed in all 17 quarters and 86,663 in fewer than 17 quarters. We report on 17,230 targets for which at least one transit signature is identified that meets the specified detection criteria: periodicity, minimum of three observed transit events, detection statistic (i.e., signal-to-noise ratio) in excess of the search threshold, and passing grade on three statistical transit consistency tests. Light curves for which a transit signal is identified are iteratively searched for additional signatures after a limb-darkened transiting planet model is fitted to the data and transit events are removed. The search for additional planets adds 16,802 transit signals for a total of 34,032; this far exceeds the number of transit signatures identified in prior pipeline runs. There was a strategic emphasis on completeness over reliability for the final Kepler transit search. A comparison of the transit signals against a set of 3402 well-established, high-quality Kepler Objects of Interest yields a recovery rate of 99.8%. The high recovery rate must be weighed against a large number of false-alarm detections. We examine characteristics of the planet population implied by the transiting planet model fits with an emphasis on detections that would represent small planets orbiting in the habitable zone of their host stars.
THE KAKEYA SET AND MAXIMAL CONJECTURES FOR ALGEBRAIC VARIETIES OVER FINITE FIELDS

Using the polynomial method of Dvir [On the size of Kakeya sets in finite fields. Preprint], we establish optimal estimates for Kakeya sets and Kakeya maximal functions associated to algebraic varieties W over finite fields F. For instance, given an (n−1)-dimensional projective variety W⊂¶n(F), we establish the Kakeya maximal estimate for all functions f:Fn→R and d≥1, where for each w∈W, the supremum is over all irreducible algebraic curves in Fn of degree at most d that pass through w but do not lie in W, and with Cn,W,d depending only on n,d and the degree of W; the special case when W is the hyperplane at infinity in particular establishes the Kakeya maximal function conjecture in finite fields, which in turn strengthens the results of Dvir.
Cross curvature flow on a negatively curved solid torus

The classic 2 ‐Theorem of Gromov and Thurston constructs a negatively curved metric on certain 3‐manifolds obtained by Dehn filling. By Geometrization, any such manifold admits a hyperbolic metric. We outline a program using cross curvature flow to construct a smooth one-parameter family of metrics between the “2 ‐metric” and the hyperbolic metric. We make partial progress in the program, proving long-time existence, preservation of negative sectional curvature, curvature bounds and integral convergence to hyperbolic for the metrics under consideration. 53C44; 57M50, 58J35, 58J32 In this note, we outline a program that uses cross curvature flow to answer certain questions inspired by the 2 ‐Theorem of Gromov and Thurston. We begin and make partial progress toward completing this program. More specifically, we consider cross curvature flow on a class of negatively curved metrics on the solid torus, the simplest nontrivial handlebody. This is motivated by the “Dehn surgery” construction in 3‐manifold topology, of which we give a brief account below. We apply the flow to a negatively curved metric described by Gromov‐Thurston on a solid torus with prescribed Dirichlet boundary conditions. Perelman’s use of Ricci flow with surgery to prove the Geometrization Conjecture demonstrates the considerable power of geometric flows to address questions about 3‐manifolds [25; 26]. Subsequent work, that of Agol‐Storm‐Thurston [3], for example, shows that Ricci flow may give information even about 3‐manifolds known a priori to admit a metric of constant curvature. The results of [3] are obtained by using the monotonicity of volume under Ricci flow with surgery. Ricci flow is nonetheless an imperfect tool for analyzing hyperbolic 3‐manifolds ‐ those admitting metrics with constant negative sectional curvatures. According to Geometrization, such manifolds form the largest class of prime 3‐manifolds. Paradoxically, they are also the least understood class. In particular, the facts that Ricci flow
A search for pulsations in the optical light curve of the nova asassn-17HX

We present high-speed optical observations of the nova ASASSN-17hx, taken both immediately after its discovery and close to its first peak in brightness, to search for seconds -- minutes pulsations associated with the convective eddy turnover timescale within the nova envelope. We do not detect any periodic signal with greater than $3\sigma$ significance. Through injection and recovery, we rule out periodic signals of fractional amplitude $>7.08\times10^{-4}$ on timescales of 2 seconds and fractional amplitude $>1.06\times10^{-3}$ on timescales of 10 minutes. Additional observations of novae are planned to further constrain ongoing simulations of the launch and propagation of nova winds.
Planar functions and perfect nonlinear monomials over finite fields

The study of finite projective planes involves planar functions, namely, functions $$f:\mathbb {F}_q\rightarrow \mathbb {F}_q$$ f : F q ? F q such that, for each $$a\in \mathbb {F}_q^*$$ a ? F q ? , the function $$c\mapsto f(c+a)-f(c)$$ c ? f ( c + a ) - f ( c ) is a bijection on $$\mathbb {F}_q$$ F q . Planar functions are also used in the construction of DES-like cryptosystems, where they are called perfect nonlinear functions. We determine all planar functions on $$\mathbb {F}_q$$ F q of the form $$c\mapsto c^t$$ c ? c t , under the assumption that $$q\ge (t-1)^4$$ q ? ( t - 1 ) 4 . This resolves two conjectures of Hernando, McGuire and Monserrat. Our arguments also yield a new proof of a conjecture of Segre and Bartocci about monomial hyperovals in finite Desarguesian projective planes.
A large-scale empirical comparison of static and dynamic test case prioritization techniques

The large body of existing research in Test Case Prioritization (TCP) techniques, can be broadly classified into two categories: dynamic techniques (that rely on run-time execution information) and static techniques (that operate directly on source and test code). Absent from this current body of work is a comprehensive study aimed at understanding and evaluating the static approaches and comparing them to dynamic approaches on a large set of projects. In this work, we perform the first extensive study aimed at empirically evaluating four static TCP techniques comparing them with state-of-research dynamic TCP techniques at different test-case granularities (e.g., method and class-level) in terms of effectiveness, efficiency and similarity of faults detected. This study was performed on 30 real-word Java programs encompassing 431 KLoC. In terms of effectiveness, we find that the static call-graph-based technique outperforms the other static techniques at test-class level, but the topic-model-based technique performs better at test-method level. In terms of efficiency, the static call-graph-based technique is also the most efficient when compared to other static techniques. When examining the similarity of faults detected for the four static techniques compared to the four dynamic ones, we find that on average, the faults uncovered by these two groups of techniques are quite dissimilar, with the top 10% of test cases agreeing on only 25% - 30% of detected faults. This prompts further research into the severity/importance of faults uncovered by these techniques, and into the potential for combining static and dynamic information for more effective approaches.
Embedded density functional theory for covalently bonded and strongly interacting subsystems

Embedded density functional theory (e-DFT) is used to describe the electronic structure of strongly interacting molecular subsystems. We present a general implementation of the Exact Embedding (EE) method [J. Chem. Phys. 133, 084103 (2010)] to calculate the large contributions of the nonadditive kinetic potential (NAKP) in such applications. Potential energy curves are computed for the dissociation of Li^+–Be, CH_3–CF_3, and hydrogen-bonded water clusters, and e-DFT results obtained using the EE method are compared with those obtained using approximate kinetic energy functionals. In all cases, the EE method preserves excellent agreement with reference Kohn–Sham calculations, whereas the approximate functionals lead to qualitative failures in the calculated energies and equilibrium structures. We also demonstrate an accurate pairwise approximation to the NAKP that allows for efficient parallelization of the EE method in large systems; benchmark calculations on molecular crystals reveal ideal, size-independent scaling of wall-clock time with increasing system size.
New Neutron-capture Measurements in 23 Open Clusters. I. The r-Process

Neutron-capture elements, those with Z > 35, are the least well-understood in terms of nucleosynthesis and formation environments. The rapid neutron-capture, or r-process, elements are formed in the environments and/or remnants of massive stars, while the slow neutron-capture, or s-process, elements are primarily formed in low-mass AGB stars. These elements can provide much information about Galactic star formation and enrichment, but observational data is limited. We have assembled a sample of 68 stars in 23 open clusters that we use to probe abundance trends for six neutron-capture elements (Eu, Gd, Dy, Mo, Pr, and Nd) with cluster age and location in the disk of the Galaxy. In order to keep our analysis as homogenous as possible, we use an automated synthesis fitting program, which also enables us to measure multiple (3-10) lines for each element. We find that the pure r-process elements (Eu, Gd, and Dy) have positive trends with increasing cluster age, while the mixed r- and s- process elements (Mo, Pr, and Nd) have insignificant trends consistent with zero. Pr, Nd, Eu, Gd, and Dy have similar, slight (though mostly statistically significant) gradients of ~0.04 dex/kpc. The mixed elements also appear to have nonlinear relationships with Galactocentric radius.
Bidirectional holographic codes and sub-AdS locality

Tensor networks implementing quantum error correcting codes have recently been used to construct toy models of holographic duality explicitly realizing some of the more puzzling features of the AdS/CFT correspondence. These models reproduce the Ryu-Takayanagi entropy formula for boundary intervals, and allow bulk operators to be mapped to the boundary in a redundant fashion. These exactly solvable, explicit models have provided valuable insight but nonetheless suffer from many deficiencies, some of which we attempt to address in this article. We propose a new class of tensor network models that subsume the earlier advances and, in addition, incorporate additional features of holographic duality, including: (1) a holographic interpretation of all boundary states, not just those in a “code” subspace, (2) a set of bulk states playing the role of “classical geometries” which reproduce the Ryu-Takayanagi formula for boundary intervals, (3) a bulk gauge symmetry analogous to diffeomorphism invariance in gravitational theories, (4) emergent bulk locality for sufficiently sparse excitations, and (5) the ability to describe geometry at sub-AdS resolutions or even flat space.