cssi/SciSciGPT-SciSciNet huggingface dataset:
Pixton's double ramification cycle relations

We prove a conjecture of Pixton, namely that his proposed formula for the double ramification cycle on Mg,n vanishes in codimension beyond g. This yields a collection of tautological relations in the Chow ring of Mg,n. We describe, furthermore, how these relations can be obtained from Pixton’s 3–spin relations via localization on the moduli space of stable maps to an orbifold projective line.
QUASI-EXCEPTIONAL DOMAINS

Exceptional domains are domains on which there exists a positive harmonic function, zero on the boundary and such that the normal derivative on the boundary is constant. Recent results classify (under some mild additional assumptions) exceptional domains as belonging to either a certain one-parameter family of simply periodic domains or one of its scaling limits. We introduce quasi-exceptional domains by allowing the boundary values to be different constants on each boundary component. This relaxed definition retains the interesting property of being an arclength quadrature domain, and also preserves the connection to the hollow vortex problem in fluid dynamics. We give a partial classification of such domains in terms of certain Abelian differentials. We also provide a new two-parameter family of periodic quasi-exceptional domains. These examples generalize the hollow vortex array found by Baker, Saffman, and Sheffield (1976). A degeneration of regions of this family provides doubly-connected examples. 2010 AMS Subject Class: 35R35, 76B47, 30C20, 31A05
The genus filtration in the smooth concordance group

We define a filtration of the smooth concordance group based on the genus of representative knots. We use the Heegaard Floer epsilon and Upsilon invariants to prove the quotient groups with respect to this filtration are infinitely generated. Results are applied to three infinite families of topologically slice knots.
Analyticity, unitarity and one-loop graviton corrections to Compton scattering

We compute the difference between the helicity flip and nonflip cross sections for graviton photoproduction on a spin-1/2 target of finite mass. Using this tree-level result, we find one-loop graviton correction to the spin-flip low-energy forward Compton scattering amplitude by using Gerasimov-Drell-Hearn sum rule. We show that this result agrees with the corresponding perturbative computations, implying the validity of the sum rule at one-loop level, contrary to the previous claims. We discuss possible effects from the black hole production and string Regge trajectory exchange at very high energies. Finally, we relate these observations with the models that involve extra dimensions.
Universal Thermodynamic Bounds on Nonequilibrium Response with Biochemical Applications

A collection of thermodynamic equalities and inequalities valid far from equilibrium constrain the response of nonequilibrium systems in terms of a driving force, offering insight into the energetic requirements of common biochemical processes.
Conformal spacelike-timelike correspondence in QCD

This paper is a study of a spacelike-timelike conformal correspondence in QCD. When the times at vertices are fixed in an A+ = 0 gauge calculation the distribution of gluons in a highly virtual decay have an exact correspondence with the gluons in the lightcone wavefunction of a high energy dipole with the identification of angles in the timelike case and transverse coordinates in the lightcone wavefunction. Divergences show up when the time integrals are done. A procedure for dropping these divergences, analogous to the Gell-Mann Low procedure in QED, allows one to define a conformal QCD, at least through NLO. Possible uses of such a conformal QCD are discussed.
An Invariant of Topologically Ordered States Under Local Unitary Transformations

For an anyon model in two spatial dimensions described by a modular tensor category, the topological S-matrix encodes the mutual braiding statistics, the quantum dimensions, and the fusion rules of anyons. It is nontrivial whether one can compute the S-matrix from a single ground state wave function. Here, we define a class of Hamiltonians consisting of local commuting projectors and an associated matrix that is invariant under local unitary transformations. We argue that the invariant is equivalent to the topological S-matrix. The definition does not require degeneracy of the ground state. We prove that the invariant depends on the state only, in the sense that it can be computed by any Hamiltonian in the class of which the state is a ground state. As a corollary, we prove that any local quantum circuit that connects two ground states of quantum double models (discrete gauge theories) with non-isomorphic abelian groups must have depth that is at least linear in the system’s diameter. As a tool for the proof, a manifestly Hamiltonian-independent notion of locally invisible operators is introduced. This gives a sufficient condition for a many-body state not to be generated from a product state by any small depth quantum circuit; this is a many-body entanglement witness.
The Euler current and relativistic parity odd transport

For a spacetime of odd dimensions endowed with a unit vector field, we introduce a new topological current that is identically conserved and whose charge is equal to the Euler character of the even dimensional spacelike foliations. The existence of this current allows us to introduce new Chern-Simons-type terms in the effective field theories describing relativistic quantum Hall states and (2 + 1) dimensional superfluids. Using effective field theory, we calculate various correlation functions and identify transport coefficients. In the quantum Hall case, this current provides the natural relativistic generalization of the Wen-Zee term, required to characterize the shift and Hall viscosity in quantum Hall systems. For the superfluid case this term is required to have nonzero Hall viscosity and to describe superfluids with non s-wave pairing.
Black Hole Ringdown: The Importance of Overtones

It is possible to infer the mass and spin of the remnant black hole from binary black hole mergers by comparing the ringdown gravitational wave signal to results from studies of perturbed Kerr spacetimes. Typically, these studies are based on the fundamental quasinormal mode of the dominant l=m=2 harmonic. By modeling the ringdown of accurate numerical relativity simulations, we find, in agreement with previous findings, that the fundamental mode alone is insufficient to recover the true underlying mass and spin, unless the analysis is started very late in the ringdown. Including higher overtones associated with this l=m=2 harmonic resolves this issue and provides an unbiased estimate of the true remnant parameters. Further, including overtones allows for the modeling of the ringdown signal for all times beyond the peak strain amplitude, indicating that the linear quasinormal regime starts much sooner than previously expected. This result implies that the spacetime is well described as a linearly perturbed black hole with a fixed mass and spin as early as the peak. A model for the ringdown beginning at the peak strain amplitude can exploit the higher signal-to-noise ratio in detectors, reducing uncertainties in the extracted remnant quantities. These results should be taken into consideration when testing the no-hair theorem.
Geometric equations for matroid varieties

Abstract Each point x in Gr ( r , n ) corresponds to an r × n matrix A x which gives rise to a matroid M x on its columns. Gel'fand, Goresky, MacPherson, and Serganova showed that the sets { y ∈ Gr ( r , n ) | M y = M x } form a stratification of Gr ( r , n ) with many beautiful properties. However, results of Mnev and Sturmfels show that these strata can be quite complicated, and in particular may have arbitrary singularities. We study the ideals I x of matroid varieties, the Zariski closures of these strata. We construct several classes of examples based on theorems from projective geometry and describe how the Grassmann-Cayley algebra may be used to derive non-trivial elements of I x geometrically when the combinatorics of the matroid is sufficiently rich.
Detaching embedded points

Suppose that XYP N differ at finitely many points: when is Y a flat limit of X union isolated points? Our main result says that this is possible when X is a local complete intersection of codimension 2 and the multiplicities are at most 3. We show by example that no hypothesis can be weakened: the conclusion fails for (a) embedded points of multiplicity > 3, (b) local complete intersections X of codimension > 2 and (c) non-local complete intersections of codimension 2. As applications, we determine the irreducible components of Hilbert schemes of space curves with high arithmetic genus and show the smoothness of the Hilbert component whose general member is a plane curve union a point in P 3 .
BPS states and algebras from quivers

We discuss several aspects of D-brane moduli spaces and BPS spectra near orbifold points. We give a procedure to determine the decay products on a line of marginal stability, and we define the algebra of BPS states in terms of quivers. These issues are illustrated in detail in the case of type-IIA theory on 2/N. We also show that many of these results can be extended to arbitrary points in the compactification moduli space using Π-stability.
Decision theory and information propagation in quantum physics

In recent papers, Zurek [(2005). Probabilities from entanglement, Born's rule pk=|ψk|2 from entanglement. Physical Review A, 71, 052105] has objected to the decision-theoretic approach of Deutsch [(1999) Quantum theory of probability and decisions. Proceedings of the Royal Society of London A, 455, 3129–3137] and Wallace [(2003). Everettian rationality: defending Deutsch's approach to probability in the Everett interpretation. Studies in History and Philosophy of Modern Physics, 34, 415–438] to deriving the Born rule for quantum probabilities on the grounds that it courts circularity. Deutsch and Wallace assume that the many worlds theory is true and that decoherence gives rise to a preferred basis. However, decoherence arguments use the reduced density matrix, which relies upon the partial trace and hence upon the Born rule for its validity. Using the Heisenberg picture and quantum Darwinism—the notion that classical information is quantum information that can proliferate in the environment pioneered in Ollivier et al. [(2004). Objective properties from subjective quantum states: Environment as a witness. Physical Review Letters, 93, 220401 and (2005). Environment as a witness: Selective proliferation of information and emergence of objectivity in a quantum universe. Physical Review A, 72, 042113]—I show that measurement interactions between two systems only create correlations between a specific set of commuting observables of system 1 and a specific set of commuting observables of system 2. This argument picks out a unique basis in which information flows in the correlations between those sets of commuting observables. I then derive the Born rule for both pure and mixed states and answer some other criticisms of the decision theoretic approach to quantum probability.
Personal Food Model

Food is central to life. Food provides us with energy and foundational building blocks for our body and is also a major source of joy and new experiences. A significant part of the overall economy is related to food. Food science, distribution, processing, and consumption have been addressed by different communities using silos of computational approaches. In this paper, we adopt a person-centric multimedia and multimodal perspective on food computing and show how multimedia and food computing are synergistic and complementary. Enjoying food is a truly multimedia experience involving sight, taste, smell, and even sound, that can be captured using a multimedia food logger. The biological response to food can be captured using multimodal data streams using available wearable devices. Central to this approach is the Personal Food Model. Personal Food Model is the digitized representation of the food-related characteristics of an individual. It is designed to be used in food recommendation systems to provide eating-related recommendations that improve the user's quality of life. To model the food-related characteristics of each person, it is essential to capture their food-related enjoyment using a Preferential Personal Food Model and their biological response to food using their Biological Personal Food Model. Inspired by the power of 3-dimensional color models for visual processing, we introduce a 6-dimensional taste-space for capturing culinary characteristics as well as personal preferences. We use event mining approaches to relate food with other life and biological events to build a predictive model that could also be used effectively in emerging food recommendation systems.
Sieving for closest lattice vectors (with preprocessing)

Lattice-based cryptography has recently emerged as a prime candidate for efficient and secure post-quantum cryptography. The two main hard problems underlying its security are the shortest vector problem (SVP) and the closest vector problem (CVP). Various algorithms have been studied for solving these problems, and for SVP, lattice sieving currently dominates in terms of the asymptotic time complexity: one can heuristically solve SVP in time \(2^{0.292d + o(d)}\) in high dimensions d [Becker–Ducas–Gama–Laarhoven, SODA’16]. Although several SVP algorithms can also be used to solve CVP, it is not clear whether this also holds for heuristic lattice sieving methods. The best time complexity for CVP is currently \(2^{0.377d + o(d)}\) [Becker–Gama–Joux, ANTS’14].
Intermediate-level crossings of a first-passage path

We investigate some simple and surprising properties of a one-dimensional Brownian trajectory with diffusion coefficient D that starts at the origin and: (i) is at X at time T, or (ii) first reaches X at time T. We determine the most likely location of the first-passage trajectory from (0, 0) to (X, T) and its distribution at any intermediate time t < T. A first-passage path typically starts out by being repelled from its final location when X2/DT 1. We also determine the distribution of times when the trajectory first crosses and last crosses an arbitrary intermediate position x < X. The distribution of first-crossing times may be unimodal or bimodal, depending on whether X2/DT 1 or X2/DT 1. The form of the first-crossing probability in the bimodal regime is qualitatively similar to, but more singular than, the well-known arcsine law.
Worldwide use and impact of the NASA Astrophysics Data System digital library

The NASA Astrophysics Data System (ADS), along with astronomy's journals and data centers (a collaboration dubbed URANIA), has developed a distributed online digital library which has become the dominant means by which astronomers search, access, and read their technical literature. Digital libraries permit the easy accumulation of a new type of bibliometric measure: the number of electronic accesses (“reads”) of individual articles. By combining data from the text, citation, and reference databases with data from the ADS readership logs we have been able to create second-order bibliometric operators, a customizable class of collaborative filters that permits substantially improved accuracy in literature queries. Using the ADS usage logs along with membership statistics from the International Astronomical Union and data on the population and gross domestic product (GDP), we have developed an accurate model for worldwide basic research where the number of scientists in a country is proportional to the GDP of that country, and the amount of basic research done by a country is proportional to the number of scientists in that country times that country's per capita GDP. We introduce the concept of utility time to measure the impact of the ADS/URANIA and the electronic astronomical library on astronomical research. We find that in 2002 it amounted to the equivalent of 736 full-time researchers, or $250 million, or the astronomical research done in France.
New insights into quantum gravity from gauge/gravity duality

Using gauge/gravity duality, we deduce several nontrivial consequences of quantum gravity from simple properties of the dual
On the interpretation of the Nernst effect measurements in the cuprates

We consider the large Nernst signal discovered by Ong and collaborators in hole-doped cuprates, in particular in the pseudogap regime. Based on our previous quantitative calculations together with Huse [Phys. Rev. Lett.89, 287001 (2002)], we discuss the interpretation of the experimental observations as arising from superconducting fluctuations and its relation to the vortex scenario proposed by Ong. We also comment on the implications of the Nernst analysis for understanding the full range of pseudogap phenomena.
Visuo-Linguistic Question Answering (VLQA) Challenge

Understanding images and text together is an important aspect of cognition and building advanced Artificial Intelligence (AI) systems. As a community, we have achieved good benchmarks over language and vision domains separately, however joint reasoning is still a challenge for state-of-the-art computer vision and natural language processing (NLP) systems. We propose a novel task to derive joint inference about a given image-text modality and compile the Visuo-Linguistic Question Answering (VLQA) challenge corpus in a question answering setting. Each dataset item consists of an image and a reading passage, where questions are designed to combine both visual and textual information i.e., ignoring either modality would make the question unanswerable. We first explore the best existing vision-language architectures to solve VLQA subsets and show that they are unable to reason well. We then develop a modular method with slightly better baseline performance, but it is still far behind human performance. We believe that VLQA will be a good benchmark for reasoning over a visuo-linguistic context. The dataset, code and leaderboard is available at https://shailaja183.github.io/vlqa/.
Resummed thermodynamic perturbation theory for bond cooperativity in associating fluids with small bond angles: Effects of steric hindrance and ring formation

In this paper we develop a thermodynamic perturbation theory for two site associating fluids which exhibit bond cooperativity (system energy is non-pairwise additive). We include both steric hindrance and ring formation such that the equation of state is bond angle dependent. Here, the bond angle is the angle separating the centers of the two association sites. As a test, new Monte Carlo simulations are performed, and the theory is found to accurately predict the internal energy as well as the distribution of associated clusters as a function of bond angle.
The Nature of a Broad-Line Radio Galaxy: Simultaneous RXTE and Chandra HETG Observations of 3C 382

We present the results from simultaneous Chandra and RXTE observations of the X-ray bright broad-line radio galaxy (BLRG) 3C 382. The long (120 ks) exposure with Chandra HETG allows a detailed study of the soft X-ray continuum and of the narrow component of the Fe Kα line. The RXTE PCA data are used to put an upper limit on the broad-line component and constrain the hard X-ray continuum. A strong soft excess below 1 keV is observed in the time-averaged HETG spectrum, which can be parameterized with a steep power law or a thermal model. The flux variability at low energies indicates that the origin of the soft excess cannot be entirely ascribed to the circumnuclear diffuse emission, detected by Chandra on scales of 20''-30'' (22-33 kpc). A narrow (σ < 90 eV) Fe Kα line (with EW< 100 eV) is observed by the Chandra HEG. Similar values for the line parameters are measured by the RXTE PCA, suggesting that the contribution from a broad-line component is negligible. The fact that the exposure is split into two observations taken 3 days apart allows us to investigate the spectral and temporal evolution of the source on different timescales. Significant flux variability associated with spectral changes is observed on timescales of hours and days. The spectral variability is similar to that observed in radio-quiet AGN ruling out a jet-dominated origin of the X-rays.
Loo.py: from fortran to performance via transformation and substitution rules

A large amount of numerically-oriented code is written and is being written in legacy languages. Much of this code could, in principle, make good use of data-parallel throughput-oriented computer architectures. Loo.py, a transformation-based programming system targeted at GPUs and general data-parallel architectures, provides a mechanism for user-controlled transformation of array programs. This transformation capability is designed to not just apply to programs written specifically for Loo.py, but also those imported from other languages such as Fortran. It eases the trade-off between achieving high performance, portability, and programmability by allowing the user to apply a large and growing family of transformations to an input program. These transformations are expressed in and used from Python and may be applied from a variety of settings, including a pragma-like manner from other languages.
Spectral DiffuserCam: lensless snapshot hyperspectral imaging with a spectral filter array

Hyperspectral imaging is useful for applications ranging from medical diagnostics to agricultural crop monitoring; however, traditional scanning hyperspectral imagers are prohibitively slow and expensive for widespread adoption. Snapshot techniques exist but are often confined to bulky benchtop setups or have low spatio-spectral resolution. In this paper, we propose a novel, compact, and inexpensive computational camera for snapshot hyperspectral imaging. Our system consists of a tiled spectral filter array placed directly on the image sensor and a diffuser placed close to the sensor. Each point in the world maps to a unique pseudorandom pattern on the spectral filter array, which encodes multiplexed spatio-spectral information. By solving a sparsity-constrained inverse problem, we recover the hyperspectral volume with sub-super-pixel resolution. Our hyperspectral imaging framework is flexible and can be designed with contiguous or non-contiguous spectral filters that can be chosen for a given application. We provide theory for system design, demonstrate a prototype device, and present experimental results with high spatio-spectral resolution.
Graphs on surfaces and Khovanov homology

Oriented ribbon graphs (dessins d’enfant) are graphs embedded in oriented surfaces. A quasi-tree of a ribbon graph is a spanning subgraph with one face, which is described by an ordered chord diagram. We show that for any link diagram L, there is an associated ribbon graph whose quasi-trees correspond bijectively to spanning trees of the graph obtained by checkerboard coloring L. This correspondence preserves the bigrading used for the spanning tree model of Khovanov homology, whose Euler characteristic is the Jones polynomial of L. Thus, Khovanov homology can be expressed in terms of ribbon graphs, with generators given by ordered chord diagrams.
The strength of regolith and rubble pile asteroids

We explore the hypothesis that, due to small van der Waals forces between constituent grains, small rubble pile asteroids have a small but non-zero cohesive strength. The nature of this model predicts that the cohesive strength should be constant independent of asteroid size, which creates a scale dependence with relative strength increasing as size decreases. This model counters classical theory that rubble pile asteroids should behave as scale-independent cohesionless collections of rocks. We explore a simple model for asteroid strength that is based on these weak forces, validate it through granular mechanics simulations and comparisons with properties of lunar regolith, and then explore its implications and ability to explain and predict observed properties of small asteroids in the NEA and Main Belt populations, and in particular of asteroid 2008 TC3. One conclusion is that the population of rapidly rotating asteroids could consist of both distributions of smaller grains (i.e., rubble piles) and of monolithic boulders.
Three-loop cusp anomalous dimension and a conjecture for n loops

I present analytical expressions for the massive cusp anomalous dimension in QCD through three loops, first calculated in 2014, in terms of elementary functions and ordinary polylogarithms. I observe interesting relations between the results at different loops and provide a conjecture for the n-loop cusp anomalous dimension in terms of the lower-loop results. I also present numerical results and simple approximate formulas for the cusp anomalous dimension relevant to top-quark production.
Differentiability of quasiconvex functions on separable Banach spaces

We investigate the differentiability properties of a real-valued quasiconvex function f defined on a separable Banach space X. Continuity is only assumed to hold at the points of a dense subset. If so, this subset is automatically residual.
Catastrophes, connectivity, and Allee effects in the design of marine reserve networks

Catastrophic events, like oil spills and hurricanes, occur in many marine systems. One potential role of marine reserves is buffering populations against disturbances, including the potential for disturbance-driven population collapses under Allee effects. This buffering capacity depends on reserves in a network providing rescue effects, with a potential trade-off in spacing between individual reserves to balance rescue via connectivity and independence of disturbances experienced. We use a set of population models to examine how dispersal ability and the disturbance regime interact to determine the optimal reserve spacing. We incorporate fishing in a spatially-explicit model to understand the consequences of objective choice (i.e. conservation versus fisheries yield) on the optimal reserve spacing. We show that the optimal spacing between reserves increases when accounting for catastrophes. This result is accentuated when Allee effects interact with catastrophes to increase the probability of extinction. We also show that classic tradeoffs between conservation and fishing objectives disappear in the presence of catastrophes. Specifically, we found that at intermediate levels of disturbance, it is optimal to spread out reserves in order to increase population persistence and to maximize spillover into non-reserve areas.
Grape seed proanthocyanidins inhibit UV radiation-induced oxidative stress and activation of MAPK and NF-κB signaling in human epidermal keratinocytes

2271 Solar ultraviolet (UV) radiation-induced oxidative stress has been implicated in various skin diseases including melanoma and nonmelanoma skin cancers. Since the use of protective clothing and sunscreens is inadequate to protect the skin from UV radiation, the use of dietary botanical supplements has received considerable interest to protect the skin from adverse biological effects of UV radiation. Earlier, we have shown that dietary grape seed proanthocyanidins (GSPs) prevent UV radiation-induced skin carcinogenesis in terms of tumor incidence, tumor multiplicity and malignant transformation of papillomas to carcinomas in mice. To define the anti-photocarcinogenic mechanism of GSPs, here we report the photoprotective effect of GSPs on UV-induced oxidative stress, and activation of mitogen-activated protein kinases (MAPK) and nuclear factor-kappa B (NF-κB) signaling pathways using normal human epidermal keratinocytes (NHEK). Treatment of NHEK with GSPs (10-50 μg/mL) inhibited UVB (10-60 mJ/cm2)-induced hydrogen peroxide (H2O2), lipid peroxidation, protein oxidation and DNA damage in the form of 8-OHdG in NHEK. GSPs have the ability to scavenge hydroxyl radicals and superoxide anions in cell-free system. GSPs also prevented UVB-induced depletion of antioxidant defense components, such as, glutathione peroxidase, catalase, superoxide dismutase and endogenous antioxidant glutathione. As UV-induced oxidative stress mediates activation of MAPK and NF-κB signaling which are involved in various skin disorders, we determined the effect of GSPs on these pathways. Treatment of NHEK with GSPs inhibited UVB-induced phosphorylation of extracellular signal-regulated kinase (ERK1/2), c-Jun N-terminal kinase (JNK) and p38 proteins of MAPK family at different time points studied. Since UV-induced H2O2 plays a major role in activation of MAPK proteins, NHEK were treated with H2O2 with or without GSPs and other known antioxidants viz., (-)-epigallocatechin-3-gallate, silymarin, ascorbic acid and N-acetylcysteine to determine their effect on H2O2-induced activation of MAPK proteins. It was observed that H2O2-induced phosphorylation of ERK1/2, JNK, and p38 was decreased by these antioxidants. Under identical conditions, GSPs also inhibited UVB-induced activation of NF-κB/p65 which was mediated through inhibition of degradation and activation of IκBα and IKKα, respectively. Taken together, it is suggested that GSPs could be useful in attenuation of UV radiation-induced oxidative stress, and oxidative stress-mediated skin diseases in human skin, however more studies are required to validate these findings in in vivo system.
Matrix measures and finite rank perturbations of self-adjoint operators

Matrix-valued measures provide a natural language for the theory of finite rank perturbations. In this paper we use this language to prove some new perturbation theoretic results. Our main result is a generalization of the Aronszajn--Donoghue theorem about the mutual singularity of the singular parts of the spectrum for rank one perturbations to the case of finite rank perturbations. Simple direct sum type examples indicate that an exact generalization is not possible. However, in this paper we introduce the notion of \emph{vector mutual singularity} for the matrix-valued measures and show that if we use this notion, the mutual singularity still holds for the finite rank perturbations. As for the scalar spectral measures and the classical mutual singularity, we show that the singular parts are mutually singular for almost all perturbations. One of the ways to prove that is to use a generalization of the Aleksandrov's spectral averaging to the matrix-valued measures, which is also one of the main results of this paper. Finally, the spectral representation of the perturbed operator is obtained. The matrix Muckenhoupt $A_2$ condition appears naturally there, and it plays an important role in establishing the vector mutual singularity of the spectral measures.
Accuracy and Performance Comparison of Video Action Recognition Approaches

Over the past few years, there has been significant interest in video action recognition systems and models. However, direct comparison of accuracy and computational performance results remain clouded by differing training environments, hardware specifications, hyperparameters, pipelines, and inference methods. This article provides a direct comparison between fourteen “off-the-shelf” and state-of-the-art models by ensuring consistency in these training characteristics in order to provide readers with a meaningful comparison across different types of video action recognition algorithms. Accuracy of the models is evaluated using standard Top-1 and Top-5 accuracy metrics in addition to a proposed new accuracy metric. Additionally, we compare computational performance of distributed training from two to sixty-four GPUs on a state-of-the-art HPC system.
Scalable Autonomous Vehicle Safety Validation through Dynamic Programming and Scene Decomposition

An open question in autonomous driving is how best to use simulation to validate the safety of autonomous vehicles. Existing techniques rely on simulated rollouts, which can be inefficient for finding rare failure events, while other techniques are designed to only discover a single failure. In this work, we present a new safety validation approach that attempts to estimate the distribution over failures of an autonomous policy using approximate dynamic programming. Knowledge of this distribution allows for the efficient discovery of many failure examples. To address the problem of scalability, we decompose complex driving scenarios into subproblems consisting of only the ego vehicle and one other vehicle. These subproblems can be solved with approximate dynamic programming and their solutions are recombined to approximate the solution to the full scenario. We apply our approach to a simple two-vehicle scenario to demonstrate the technique as well as a more complex five-vehicle scenario to demonstrate scalability. In both experiments, we observed an increase in the number of failures discovered compared to baseline approaches.
Influence of Plant Host and Organ, Management Strategy, and Spore Traits on Microbiome Composition

Microbiomes from maize and soybean were characterized in a long-term three-crop rotation research site, under four different land management strategies, to begin unraveling the effects of common fa...
Quantum Mechanical Out-Of-Time-Ordered-Correlators for the Anharmonic (Quartic) Oscillator

Out-of-time-ordered correlators (OTOCs) have been suggested as a means to study quantum chaotic behavior in various systems. In this work, I calculate OTOCs for the quantum mechanical anharmonic oscillator with quartic potential, which is classically integrable and has a Poisson-like energy-level distribution. For low temperature, OTOCs are periodic in time, similar to results for the harmonic oscillator and the particle in a box. For high temperature, OTOCs exhibit a rapid (but power-like) rise at early times, followed by saturation consistent with 2〈x$^{2}$〉$_{T}$〈p$^{2}$〉$_{T}$ at late times. At high temperature, the spectral form factor decreases at early times, bounces back and then reaches a plateau with strong fluctuations.
ApoE4 Impairs Neuron-Astrocyte Coupling of Fatty Acid Metabolism

Alzheimer's disease (AD) risk gene ApoE4 perturbs brain lipid homeostasis and energy transduction. However, the cell-type-specific mechanism of ApoE4 in modulating brain lipid metabolism is unclear. Here, we describe a detrimental role of ApoE4 in regulating fatty acid (FA) metabolism across neuron and astrocyte in tandem with their distinctive mitochondrial phenotypes. ApoE4 disrupts neuronal function by decreasing FA sequestering in lipid droplets (LDs). FAs in neuronal LDs are exported and internalized by astrocytes, with ApoE4 diminishing the transport efficiency. Further, ApoE4 lowers FA oxidation and leads to lipid accumulation in both astrocyte and the hippocampus. Importantly, diminished capacity of ApoE4 astrocytes in eliminating neuronal lipids and degrading FAs accounts for their compromised metabolic and synaptic support to neurons. Collectively, our findings reveal a mechanism of ApoE4 disruption to brain FA and bioenergetic homeostasis that could underlie the accelerated lipid dysregulation and energy deficits and increased AD risk for ApoE4 carriers.
The Dynamics of Social Responsibility: Processes, Positions, and Paths in the Oil and Gas Industry

I use corporate strategy concepts and tools to focus on the dynamics of firm social initiatives and actions over time. I examine the different paths and positions taken by firms, and the processes that may underlie such paths and positions. My sample comprises 19 firms in the oil and gas industry, and covers the decade from 1991–2000. I use an exploratory approach that mixes qualitative and quantitative cluster analysis as the primary tools to examine this industry, and to isolate and examine distinct social responsibility positions and paths taken by these firms. I also provide evidence about which theoretical processes seem to best explain these choices.
Competition and Business Strategy in Historical Perspective

A review of theories of competition and business strategy over the last half-century reveals a fairly linear development of early work by academics and consultants into efforts to understand the determinants of industry profitability and competitive position and, more recently, to add a time or historical dimension to the analysis. The possible implications of the emergence of a market for such ideas are also discussed. trategy” is a term that can be traced back to the ancient Greeks, for whom it meant a chief magistrate or a military commander in chief. The use of the term in business, however, dates only to the twentieth century, and its use in a self-consciously competitive context is even more recent. After providing some historical background, this essay focuses on how the evolution of ideas about business strategy was influenced by competitive thinking in the second half of the twentieth century. The review aims not to be comprehensive but, instead, to focus on some key topical issues in applying competitive thinking to business strategy. Particular attention is paid to the role of three institutions —Harvard Business School and two consulting firms, the Boston Consulting Group and McKinsey & Company —in looking at the historical development and diffusion of theories of business competition and strategy. The essay concludes with some discussion of how the emergence of a market for ideas in this broad domain is likely to affect future developments in this area.
A tight approximation for an EOQ model with supply disruptions

Abstract We consider a continuous-review inventory model for a firm that faces deterministic demand but whose supplier experiences random supply disruptions. The supplier experiences “wet” and “dry” (operational and disrupted) periods whose durations are exponentially distributed. The firm follows an EOQ-like policy during wet periods but may not place orders during dry periods; any demands occurring during dry periods are lost if the firm does not have sufficient inventory to meet them. This paper introduces a simple but effective approximation for this model that maintains the tractability of the classical EOQ and permits analysis similar to that typically performed for the EOQ. We provide analytical and numerical bounds on the approximation error in both the cost function and the optimal order quantity. We prove that the optimal power-of-two policy has a worst-case error bound of 6%. Finally, we demonstrate numerically that the results proved for the approximate cost function hold, at least approximately, for the original exact function.
Five Views of the Great Lakes and Why They Might Matter

Compared to many of the world's contested international watersheds such as the Amu Darya in Central Asia, the Colorado River, or the Nile Basin, the Canadian-United States Great Lakes Basin is a paradox: the level of controversy about the management and use of the waters is inverse to the amount of water in the basin. The lakes themselves contain twenty percent of the world's fresh water). However, comparatively little of this water is currently withdrawn, and only about five percent of that amount is consumed and not returned to the watershed. In 2002, the International Joint Commission (IJC), the Canadian-United States body which administers the 1909 Boundary Waters Treaty, revised its previous consumptive use estimates downward by eighteen percent. Out-of-basin diversions are even smaller. The major transbasin diversion is the Chicago diversion. Chicago and its lakeshore suburbs are authorized by a United States Supreme Court decree to with-draw 3,200 cubic feet per second from Lake Michigan. Only the fact that the Mississippi watershed encompasses most of the metropolitan Chicago area makes this a transbasin diversion. The other major transwatershed diversion, the Long Lake and Ogoki diversions, actually add water to Lake Superior. However, despite the modest levels of present and projected consumptive use and the vast amount of water in the lakes, fears about future in-basin consumptive uses and transbasin diversions have been a major political and legal issue in the basin for more than two decades.
Competition and Efficiency in Congested Markets

We study the efficiency of oligopoly equilibria (OE) in congested markets. The motivating examples are the allocation of network flows in a communication network or of traffic in a transportation network. We show that increasing competition among oligopolists can reduce efficiency, measured as the difference between users' willingness to pay and delay costs. We characterize a tight bound of 5/6 on efficiency in pure strategy equilibria when there is zero latency at zero flow and a tight bound of 2√2 - 2 with positive latency at zero flow. These bounds are tight even when the numbers of routes and oligopolists are arbitrarily large.
The New Energy Geopolitics?: China, Renewable Energy, and the "Greentech Race"

Programs in China promoting development of new renewable energy capacity have produced astonishing achievements in a short period of time. Evoking the “space race” between the United States and the U.S.S.R. after the launch of the Sputnik satellite in 1957, observers contend that the United States and China are in a “greentech race” to secure international leadership in the development and deployment of renewable energy. This article finds that China’s programs and initiatives are indeed leading to considerable success, but, using three different metrics (growth of China’s greentech industry, levels of government support and financing, and installed capacity figures), finds that claims that China is “winning” the “greentech race” are currently overstated. Continuing on to discuss the link between climate change and national security, the article concludes that the “greentech race” metaphor is counterproductive, and the “race” rhetoric should be downplayed for two major reasons. First, it would hamper continued cooperation between the United States and China on climate matters, which is essential given the world’s pressing needs to address climate change. Second, using a detailed description of the security threat posed in each situation, the article finds that the national security background to the growth of renewable energy is considerably different from that which prompted the growth of the United States’ space industry after the Sputnik launch, and concludes that the “race” metaphor is an inappropriate fit to the present situation. Finally, the article finds that the most productive response to concerns about the growth of renewable energy sector in China would be stronger programs and initiatives to encourage the renewable energy industry in the United States.
"And to the Republic for Which It Stands": Guaranteeing a Republican Form of Government

Most scholars who have addressed voter initiatives suggest only that the Guarantee Clause requires that the Supreme Court take a more active role in reviewing the constitutionality of state initiative measures. In contrast, we argue in this Essay that the Guarantee Clause establishes a per se prohibition against state initiatives. Part I of this Essay briefly examines the historical origins of the Guarantee Clause and the Founders’ apprehensions of direct democracy. Part II observes how modern state initiatives provide contemporary illustrations of the Founders’ philosophical concerns about direct democracy. Part III concludes that state initiative measures constitute per se violations of the Guarantee Clause and, accordingly, must be summarily rejected. In so concluding, this Essay rejects proposals that courts review direct legislation or certain genres of direct legislation under heightened scrutiny.
Too-Systemic-to-Fail: What Option Markets Imply about Sector-Wide Government Guarantees

We examine the pricing of financial crash insurance during the 2007– 2009 financial crisis in US option markets, and we show that a large amount of aggregate tail risk is missing from the cost of financial sector crash insurance during the crisis. The difference in costs between out-of-the-money put options for individual banks and puts on the financial sector index increases four-fold from its precrisis 2003–2007 level. We provide evidence that a collective government guarantee for the financial sector lowers index put prices far more than those of individual banks and explains the increase in the basket-index put spread. (JEL E44, G01, G13, G21, G28, H81)
Response-adaptive designs for clinical trials: Simultaneous learning from multiple patients

Abstract Clinical trials have traditionally followed a fixed design, in which randomization probabilities of patients to various treatments remains fixed throughout the trial and specified in the protocol. The primary goal of this static design is to learn about the efficacy of treatments. Response-adaptive designs, on the other hand, allow clinicians to use the learning about treatment effectiveness to dynamically adjust randomization probabilities of patients to various treatments as the trial progresses. An ideal adaptive design is one where patients are treated as effectively as possible without sacrificing the potential learning or compromising the integrity of the trial. We propose such a design, termed Jointly Adaptive, that uses forward-looking algorithms to fully exploit learning from multiple patients simultaneously. Compared to the best existing implementable adaptive design that employs a multiarmed bandit framework in a setting where multiple patients arrive sequentially, we show that our proposed design improves health outcomes of patients in the trial by up to 8.6 percent, in expectation, under a set of considered scenarios. Further, we demonstrate our design’s effectiveness using data from a recently conducted stent trial. This paper also adds to the general understanding of such models by showing the value and nature of improvements over heuristic solutions for problems with short delays in observing patient outcomes. We do this by showing the relative performance of these schemes for maximum expected patient health and maximum expected learning objectives, and by demonstrating the value of a restricted-optimal-policy approximation in a practical example.
Do Short Sellers Target Firms with Poor Earnings Quality? Evidence from Earnings Restatements

We study the behavior of short sellers around earnings restatements. We find that short sellers accumulate positions in restating firms several months in advance of the restatement and subsequently unwind these positions after the drop in share price induced by the restatement. The increase in short interest is larger for firms with high levels of accruals prior to restatement. We document that heavily shorted firms experience poor subsequent performance and a higher rate of delisting. Overall, these results suggest that the motive for short selling is, at least in part, related to suspect financial reporting and that short sellers pay attention to information being conveyed by accruals.
Does the five-factor model of personality relate to goal orientation?

Abstract Although the personality-motivation link has been studied previously, this literature has largely overlooked goal orientation. Using a field sample, this study explored the linkages between the five-factor model of personality and goal orientation. Results indicated that the “Big Two” (Extraversion and Neuroticism) were important correlates of goal orientation. Specifically, Extraversion was significantly related to learning goal orientation and proving goal orientation. Neuroticism was marginally related to proving goal orientation and significantly related to avoiding goal orientation. Theoretical and practical implications of the results are discussed.
In Harm's Way? Payday Loan Access and Military Personnel Performance

Does borrowing at 400% APR do more harm than good? The U.S. Department of Defense thinks so and successfully lobbied for a 36% APR cap on loans to servicemen. But existing evidence on how access to high-interest debt affects borrowers is inconclusive. We estimate effects of payday loan access on enlisted personnel using exogenous variation in Air Force rules assigning personnel to bases across the United States, and within-state variation in lending laws over time. Airmen job performance and retention declines with payday loan access, and severely poor readiness increases. These effects are strongest among relatively inexperienced and financially unsophisticated airmen.