cssi/SciSciGPT-SciSciNet huggingface dataset:
A Bayesian Calibration–Prediction Method for Reducing Model-Form Uncertainties with Application in RANS Simulations

Model-form uncertainties in complex mechanics systems are a major obstacle for predictive simulations. Reducing these uncertainties is critical for stake-holders to make risk-informed decisions based on numerical simulations. For example, Reynolds-Averaged Navier-Stokes (RANS) simulations are increasingly used in the design, analysis, and safety assessment of mission-critical systems involving turbulent flows. However, for many practical flows the RANS predictions have large model-form uncertainties originating from the uncertainty in the modeled Reynolds stresses. Recently, a physics-informed Bayesian framework has been proposed to quantify and reduce model-form uncertainties in RANS simulations for flows by utilizing sparse observation data. However, in the design stage of engineering systems, when the system or device has not been built yet, measurement data are usually not available. In the present work we extend the original framework to scenarios where there are no available data on the flow to be predicted. In the proposed method, we first calibrate the model discrepancy on a related flow with available data, leading to a statistical model for the uncertainty distribution of the Reynolds stress discrepancy. The obtained distribution is then sampled to correct the RANS-modeled Reynolds stresses for the flow to be predicted. The extended framework is a Bayesian calibration–prediction method for reducing model-form uncertainties. The merits of the proposed method are demonstrated on two flows that are challenging to standard RANS models. By not requiring observation data on the flow to be predicted, the present calibration–prediction method will gain wider acceptance in practical engineering design and analysis compared to the original framework. While RANS modeling is chosen to demonstrate the merits of the proposed framework, the methodology is generally applicable to other complex mechanics models involving solids, fluids flows, or the coupling between the two (e.g., mechanics models for the cardiovascular systems), where model-form uncertainties are present in the constitutive relations.
Automated lifespan determination across Caenorhabditis strains and species reveals assay-specific effects of chemical interventions

The goal of the Caenorhabditis Intervention Testing Program is to identify robust and reproducible pro-longevity interventions that are efficacious across genetically diverse cohorts in the Caenorhabditis genus. The project design features multiple experimental replicates collected by three different laboratories. Our initial effort employed fully manual survival assays. With an interest in increasing throughput, we explored automation with flatbed scanner-based Automated Lifespan Machines (ALMs). We used ALMs to measure survivorship of 22 Caenorhabditis strains spanning three species. Additionally, we tested five chemicals that we previously found extended lifespan in manual assays. Overall, we found similar sources of variation among trials for the ALM and our previous manual assays, verifying reproducibility of outcome. Survival assessment was generally consistent between the manual and the ALM assays, although we did observe radically contrasting results for certain compound interventions. We found that particular lifespan outcome differences could be attributed to protocol elements such as enhanced light exposure of specific compounds in the ALM, underscoring that differences in technical details can influence outcomes and therefore interpretation. Overall, we demonstrate that the ALMs effectively reproduce a large, conventionally scored dataset from a diverse test set, independently validating ALMs as a robust and reproducible approach toward aging-intervention screening.
The Kelmans-Seymour conjecture IV: A proof

Abstract A well known theorem of Kuratowski in 1932 states that a graph is planar if, and only if, it does not contain a subdivision of K 5 or K 3 , 3 . Wagner proved in 1937 that if a graph other than K 5 does not contain any subdivision of K 3 , 3 then it is planar or it admits a cut of size at most 2. Kelmans and, independently, Seymour conjectured in the 1970s that if a graph does not contain any subdivision of K 5 then it is planar or it admits a cut of size at most 4. In this paper, we give a proof of the Kelmans-Seymour conjecture. We also discuss several related results and problems.
On Einstein Manifolds of Positive Sectional Curvature

Let (M, g) be a compact oriented four-dimensional Einstein manifold. If M has positive intersection form and g has non-negative sectional curvature, we show that, up to rescaling and isometry, (M, g) is ℂℙ2, with its standard Fubini–Study metric.
Precise timing is ubiquitous, consistent, and coordinated across a comprehensive, spike-resolved flight motor program

Sequences of action potentials, or spikes, carry information in the number of spikes and their timing. Spike timing codes are critical in many sensory systems, but there is now growing evidence that millisecond-scale changes in timing also carry information in motor brain regions, descending decision-making circuits, and individual motor units. Across all of the many signals that control a behavior, how ubiquitous, consistent, and coordinated are spike timing codes? Assessing these open questions ideally involves recording across the whole motor program with spike-level resolution. To do this, we took advantage of the relatively few motor units controlling the wings of a hawk moth, Manduca sexta. We simultaneously recorded nearly every action potential from all major wing muscles and the resulting forces in tethered flight. We found that timing encodes more information about turning behavior than spike count in every motor unit, even though there is sufficient variation in count alone. Flight muscles vary broadly in function as well as in the number and timing of spikes. Nonetheless, each muscle with multiple spikes consistently blends spike timing and count information in a 3:1 ratio. Coding strategies are consistent. Finally, we assess the coordination of muscles using pairwise redundancy measured through interaction information. Surprisingly, not only are all muscle pairs coordinated, but all coordination is accomplished almost exclusively through spike timing, not spike count. Spike timing codes are ubiquitous, consistent, and essential for coordination.
Polariton Assisted Down-Conversion of Photons via Nonadiabatic Molecular Dynamics: A Molecular Dynamical Casimir Effect.

Quantum dynamics of the photoisomerization of a single 3,3'-diethyl-2,2'-thiacynine iodide molecule embedded in an optical microcavity was theoretically studied. The molecular model consisting of two electronic states and the reaction coordinate was coupled to a single cavity mode via the quantum Rabi Hamiltonian, and the corresponding time-dependent Schrodinger equation starting with a purely molecular excitation was solved using the Multiconfigurational Time-Dependent Hartree Method (MCTDH). We show that, for single-molecule strong coupling with the photon mode, nonadiabatic molecular dynamics produces mixing of polariton manifolds with differing number of excitations, without the need of counter-rotating light-matter coupling terms. Therefore, an electronic excitation of the molecule at the cis configuration is followed by the generation of two photons in the trans configuration upon isomerization. Conditions for this phenomenon to be operating in the collective strong light-matter coupling regime are discussed and found to be unfeasible for the present system, based on simulations of two molecules inside the microcavity. Yet, our finding suggests a new mechanism that, without ultrastrong coupling, achieves photon down-conversion by exploiting the emergent molecular dynamics arising in polaritonic architectures.
Labor Market Dynamics: A Hidden Markov Approach

This paper proposes a hidden state Markov model (HMM) that incorporates workers’ unobserved labor market attachment into the analysis of labor market dynamics. Unlike previous literature, which typically assumes that a worker’s observed labor force status follows a first-order Markov process, the proposed HMM allows workers with the same labor force status to have different history-dependent transition probabilities. I show that the estimated HMM generates labor market transition probabilities that match those observed in the data, while the first-order Markov model (FOM) and its many-state extensions cannot. Even compared with the extended FOM, the HMM improves the fit of the empirical transition probabilities by a factor of 30. I apply the HMM to (1) calculate the long-run consequences of separation from stable employment, (2) study evolutions of employment stability across different demographic groups over the past several decades, (3) compare the dynamics of labor market flows during the Great Recession to those during the 1981 recession, and (4) highlight the importance of looking beyond distributions of current labor force status.
The cohomology of semi-infinite Deligne–Lusztig varieties

We prove a 1979 conjecture of Lusztig on the cohomology of semi-infinite Deligne--Lusztig varieties attached to division algebras over local fields. We also prove the two conjectures of Boyarchenko on these varieties. It is known that in this setting, the semi-infinite Deligne--Lusztig varieties are ind-schemes comprised of limits of certain finite-type schemes $X_h$. Boyarchenko's two conjectures are on the maximality of $X_h$ and on the behavior of the torus-eigenspaces of their cohomology. Both of these conjectures were known in full generality only for division algebras with Hasse invariant $1/n$ in the case $h = 2$ (the "lowest level") by the work of Boyarchenko--Weinstein on the cohomology of a special affinoid in the Lubin--Tate tower. We prove that the number of rational points of $X_h$ attains its Weil--Deligne bound, so that the cohomology of $X_h$ is pure in a very strong sense. We prove that the torus-eigenspaces of $H_c^i(X_h)$ are irreducible representations and are supported in exactly one cohomological degree. Finally, we give a complete description of the homology groups of the semi-infinite Deligne--Lusztig varieties attached to any division algebra, thus giving a geometric realization of the unramified supercuspidal representations of these groups. We expect that the techniques developed in this paper will be useful in studying these constructions for reductive groups over local fields in general.
Remarks on enveloping semigroups

The local structures of enveloping semigroups of simple groups are investigated. All J-coirreducible connected stabilizer submonoids are determined. The notion of a navel of a reductive monoid is i...
Material characterization and precise finite element analysis of fiber reinforced thermoplastic composites for 4D printing

Abstract Four-dimensional (4D) printing, a new technology emerged from additive manufacturing (3D printing), is widely known for its capability of programming post-fabrication shape-changing into artifacts. Fused deposition modeling (FDM)-based 4D printing, in particular, uses thermoplastics to produce artifacts and requires computational analysis to assist the design processes of complex geometries. However, these artifacts are weak against structural loads, and the design quality can be limited by less accurate material models and numerical simulations. To address these issues, this paper propounds a composite structure design made of two materials – polylactic acid (PLA) and carbon fiber reinforced PLA (CFPLA) – to increase the structural strength of 4D printed artifacts and a workflow composed of several physical experiments and series of dynamic mechanical analysis (DMA) to characterize materials. We apply this workflow to 3D printed samples fabricated with different printed parameters to accurately characterize the materials and implement a sequential finite element analysis (FEA) to achieve accurate simulations. The accuracy of deformation induced by the triggering process is both computationally and experimentally verified with several creative design examples and is measured to be at least 95%, with a confidence interval of ( 0 . 972 , 0 . 985 ) . We believe the presented workflow is essential to the combination of geometry, material mechanism and design, and has various potential applications.
The Challenge of Reducing Patient Falls in Hospitals.

Greeley and colleagues' systematic review highlighted the paucity of evidence on the effectiveness of sitters and alternatives to sitters in preventing falls among patients in acute care hospitals....
Satellite ruling polynomials, DGA representations, and the colored HOMFLY-PT polynomial

We establish relationships between two classes of invariants of Legendrian knots in $\mathbb{R}^3$: Representation numbers of the Chekanov-Eliashberg DGA and satellite ruling polynomials. For positive permutation braids, $\beta \subset J^1S^1$, we give a precise formula in terms of representation numbers for the $m$-graded ruling polynomial $R^m_{S(K,\beta)}(z)$ of the satellite of $K$ with $\beta$ specialized at $z=q^{1/2}-q^{-1/2}$ with $q$ a prime power, and we use this formula to prove that arbitrary $m$-graded satellite ruling polynomials, $R^m_{S(K,L)}$, are determined by the Chekanov-Eliashberg DGA of $K$. Conversely, for $m\neq 1$, we introduce an $n$-colored $m$-graded ruling polynomial, $R^m_{n,K}(q)$, in strict analogy with the $n$-colored HOMFLY-PT polynomial, and show that the total $n$-dimensional $m$-graded representation number of $K$ to $\mathbb{F}_q^n$, $\mbox{Rep}_m(K,\mathbb{F}_q^n)$, is exactly equal to $R^m_{n,K}(q)$. In the case of $2$-graded representations, we show that $R^2_{n,K}=\mbox{Rep}_2(K, \mathbb{F}_q^n)$ arises as a specialization of the $n$-colored HOMFLY-PT polynomial.
Boronic, diboronic and boric acid esters of 1,8-naphthalenediol - synthesis, structure and formation of boronium salts.

The 1,8-naphthalenediolate [1,8-O2C10H8] supported boronic and boric acid esters of general formula X-B(1,8-O2C10H8), where X = C6H5 (1a), C6F5 (2a), 3,4,5-F3-C6H2 (3a), 2,4,6-F3-C6H2 (4a), 2,6-F2-C6H3 (5a), 2,6-Cl2-C6H3 (6a), 2,4,6-Me3-C6H2 (7a), 2,6-(MeO)3-C6H3 (8a), Bun (9a), MeO (10a), OH (11a) and Cl (13a), were synthesized, NMR spectroscopically characterized, and the solid-state structures of 1a–5a, 8a and 10a determined by X-ray crystallography. The acceptor numbers of 1a–7a and 13a were determined and found to be similar to their catecholate analogues, R-Bcat, indicating similar Lewis acidities of these two classes of boronic acid esters. The reaction of B2(NMe2)4 with 1,8-naphthalenediol, followed by addition of HCl furnished the diboronic acid ester B2(1,8-O2C10H8)4 (16a) in ca. 70% yield. Cl-B(1,8-O2C10H8) (13a) was shown to react with OPEt3, DMAP, 1,10-phenanthroline and 2,2′-bipyridine, resp., to give the boronium salts [(Et3PO)2B(1,8-O2C10H8)]Cl (18a), [(DMAP)2B(1,8-O2C10H8)]Cl (22a), [(2,2′-bipyridine)B(1,8-O2C10H8)]Cl (23a) and [(1,10-phenanthroline)B(1,8-O2C10H8)]Cl (24a), which were characterized by NMR spectroscopy and X-ray crystallography.
Nonlinear Uncertainty Control with Iterative Covariance Steering

This paper considers the problem of steering the state distribution of a nonlinear stochastic system from an initial Gaussian to a terminal distribution with a specified mean and covariance, subject to probabilistic path constraints. An algorithm is developed to solve this problem by iteratively solving an approximate linearized problem as a convex program. This method, which we call iterative covariance steering (iCS), is numerically demonstrated by controlling a double integrator with quadratic drag force subject to additive Brownian noise while satisfying probabilistic path constraints.
Dissociation between frontal and temporal-parietal contributions to connected speech in acute stroke

Humans are uniquely able to retrieve and combine words into syntactic structure to produce connected speech. Previous identification of focal brain regions necessary for production focused primarily on associations with the content produced by speakers with chronic stroke, where function may have shifted to other regions after reorganization occurred. Here, we relate patterns of brain damage with deficits to the content and structure of spontaneous connected speech in 52 speakers during the acute stage of a left hemisphere stroke. Multivariate lesion behaviour mapping demonstrated that damage to temporal-parietal regions impacted the ability to retrieve words and produce them within increasingly complex combinations. Damage primarily to inferior frontal cortex affected the production of syntactically accurate structure. In contrast to previous work, functional-anatomical dissociations did not depend on lesion size likely because acute lesions were smaller than typically found in chronic stroke. These results are consistent with predictions from theoretical models based primarily on evidence from language comprehension and highlight the importance of investigating individual differences in brain-language relationships in speakers with acute stroke.
Transcriptome profiling of Variovorax paradoxus EPS under different growth conditions reveals regulatory and structural novelty in biofilm formation

We used transcriptome analysis by paired-end strand-specific RNA-seq to evaluate the specific changes in gene expression associated with the transition to static biofilm growth in the rhizosphere plant growth-promoting bacterium Variovorax paradoxus EPS. Triplicate biological samples of exponential growth, stationary phase and static biofilm samples were examined. DESeq2 and Rockhopper were used to identify robust and widespread shifts in gene expression specific to each growth phase. We identified 1711 protein-coding genes (28%) using DESeq2 that had altered expression greater than twofold specifically in biofilms compared to exponential growth. Fewer genes were specifically differentially expressed in stationary-phase culture (757, 12%). A small set of genes (103/6020) were differentially expressed in opposing fashions in biofilm and stationary phase, indicating potentially substantial shifts in phenotype. Gene-ontology analysis showed that the only class of genes specifically upregulated in biofilms was associated with nutrient transport, highlighting the importance of nutrient uptake in the biofilm. The biofilm-specific genes did not overlap substantially with the loci identified by mutagenesis studies, although some were present in both sets. The most highly upregulated biofilm-specific gene is predicted to be a part of the RNA degradosome, which indicates that RNA stability is used to regulate the biofilm phenotype. Two small putative proteins, Varpa_0407 and Varpa_3832, are highly expressed specifically in biofilms and are predicted to be secreted DNA-binding proteins, which may stabilize extracellular DNA as a component of the biofilm matrix. An flp/tad type-IV pilus locus (Varpa_5148-60) is strongly downregulated specifically in biofilms, in contrast with results from other systems for these pili. Mutagenesis confirms that this locus is important in surface motility rather than biofilm formation. These experimental results suggest that V. paradoxus EPS biofilms have substantial regulatory and structural novelty.
Proteoglycan IMPG2 Shapes the Interphotoreceptor Matrix and Modulates Vision

Photoreceptor neurons are surrounded by an extracellular matrix, called the interphotoreceptor matrix (IPM). Activities crucial to vision occur within the IPM, including trafficking of nutrients and metabolites, retinal attachment, and interactions needed for normal outer segment phagocytosis. The IPM includes the following two unique proteoglycans: IPM proteoglycan 1 (IMPG1) and IMPG2. Patients with mutations in IMPG1/IMPG2 develop visual deficits with subretinal material accumulation, highlighting the critical role of the IPM in vision. To determine the role of these proteoglycans in retinal physiology and the pathologic mechanisms that lead to vision loss, we generated mouse models lacking IMPG1/IMPG2. In normal retina, IMPG1 and IMPG2 occupy distinct IPM compartments, represent the main source of chondroitin sulfate and are fundamental for the constitution of the cone-specific glycocalyx stained by the PNA (peanut agglutinin) lectin marker. No evident morphologic or functional deficits were found in mice lacking IMPG1. In the absence of IMPG2, IMPG1 abnormally accumulated at the subretinal space need, likely leading to the formation of subretinal lesions and reduced visual function. Interestingly, mice lacking both IMPG1 and IMPG2, regardless of sex, showed normal retinal structure and function, demonstrating that the aberrant IMPG1 distribution is the main cause of the visual alterations observed in the absence of IMPG2. In conclusion, our results show the dependence of secreted proteoglycans such as IMPG1 on the extracellular environment to properly integrate into the matrix, demonstrate the role of IMPG2 in shaping the IPM, and shed light on the potential mechanisms leading to the development of subretinal lesions and vision loss.SIGNIFICANCE STATEMENT The photoreceptors are specialized neurons that drive phototransduction in the mammalian retina. These cells are organized and surrounded by an extracellular matrix, the interphotoreceptor matrix (IPM). Mutations in IPM proteoglycans are associated with blindness in humans. Our studies show that two specific proteoglycans of the IPM, IPM proteoglycan 1 (IMPG1) and IMPG2, form a dynamic structure with distinct localization and dependency. When IMPG2 is absent, IMPG1 cannot integrate into the IPM, leading to abnormal proteoglycan accumulation and visual deficits. This work adds a new layer of understanding to IPM physiology and describes the pathologic events following deficits in proteoglycans, providing novel possibilities for visual restoration in patients with IMPG-related pathologies.
Optimizing for Distributional Goals in School Choice Problems

I investigate three goals of school choice: welfare, encouraging neighborhood schools, and diversity. I use optimization problems to find the best stable and incentive compatible match for any comb...
Parallel vector processing of multidimensional orthogonal transforms for digital signal processing applications

This paper presents vector and parallel algorithms and implementations of one- and two-dimensional orthogonal transforms. The speed performances are evaluated on Cray X-MP/48 vector computer. The sinusoidal orthogonal transforms are computed using fast real Fourier transform (FFT) kernel. The non-sinusoidal orthogonal transform algorithms are derived by using direct factorizations of transform matrices. Concurrent processing is achieved by using the multitasking capability of Cray X-MP/48 to transform long data vectors and two-dimensional data vectors. The discrete orthogonal transforms discussed in this paper include: Fourier transform (DFT), cosine transform (DCT), sine transform (DST), Hartley transform (DHT), Walsh transform (DWHT) and Hadamard transform (DHDT). The factors affecting the speedup of vector and parallel processing of these transforms are considered. The vectorization techniques are illustrated by an FFT example.
High-speed interferometric imaging reveals dynamics of neuronal deformation during the action potential

Neurons undergo nanometer-scale deformations during action potentials, and the underlying mechanism has been actively debated for decades. Previous observations were limited to a single spot or the cell boundary, while movement across the entire neuron during the action potential remained unclear. Here we report full-field imaging of cellular deformations accompanying the action potential in mammalian neuron somas (-1.8 to 1.4 nm) and neurites (-0.7 to 0.9 nm), using high-speed quantitative phase imaging with a temporal resolution of 0.1 ms and an optical path length sensitivity of <4 pm per pixel. The spike-triggered average, synchronized to electrical recording, demonstrates that the time course of the optical phase changes closely matches the dynamics of the electrical signal. Utilizing the spatial and temporal correlations of the phase signals across the cell, we enhance the detection and segmentation of spiking cells compared to the shot-noise-limited performance of single pixels. Using three-dimensional (3D) cellular morphology extracted via confocal microscopy, we demonstrate that the voltage-dependent changes in the membrane tension induced by ionic repulsion can explain the magnitude, time course, and spatial features of the phase imaging. Our full-field observations of the spike-induced deformations shed light upon the electromechanical coupling mechanism in electrogenic cells and open the door to noninvasive label-free imaging of neural signaling.
Static and dynamic functional connectivity analysis of cerebrovascular reactivity: An fMRI study

BACKGROUND Cerebrovascular reactivity (CVR) is an important aspect of brain function, and as such it is important to understand relationship between CVR and functional connectivity. METHODS This research studied the role of CVR, or the brain's ability to react to vasoactive stimuli on brain functional connectivity by scanning subjects with blood-oxygenation-level-dependent (BOLD) functional magnetic resonance imaging (fMRI) while they periodically inhale room air and a CO 2-enriched gas mixture. We developed a new metric to measure the effect of CVR on each intrinsic connectivity network (ICN), which contrasts to voxel-wise CVR. We also studied the changes in whole-brain connectivity patterns using both static functional network connectivity (sFNC) and dynamic FNC (dFNC). RESULTS We found that network connectivity is generally weaker during vascular dilation, which is supported by previous research. The dFNC analysis revealed that participants did not return to the pre-CO 2 inhalation state, suggesting that one-minute periods of room-air inhalation is not enough for the CO 2 effect to fully dissipate. CONCLUSIONS Cerebrovascular reactivity is one tool that the cerebrovascular system uses to ensure the constant, finely-tuned flow of oxygen to function properly. Understanding the relationship between CVR and brain dynamism can provide unique information about cerebrovascular diseases and general brain function. We observed that CVR has a wide, but consistent relationship to connectivity patterns between functional networks.
Predicting Student Performance in an Educational Game Using a Hidden Markov Model

Contributions: Prior studies on education have mostly followed the model of the cross-sectional study, namely, examining the pretest and the posttest scores. This article shows that students’ knowledge throughout the intervention can be estimated by time-series analysis using a hidden Markov model (HMM). Background: Analyzing time series and the interaction between the students and the game data can result in valuable information that cannot be gained by only cross-sectional studies of the exams. Research Questions: Can an HMM be used to analyze the educational games? Can an HMM be used to make a prediction of the students’ performance? Methodology: The study was conducted on ( $N=854$ ) students who played the Save Patch game. Students were divided into class 1 and class 2. Class 1 students are those who scored lower in the posttest than class 2 students. The analysis is done by choosing various features of the game as the observations. Findings: The state trajectories can predict the students’ performance accurately for both classes 1 and 2.
Runs versus Lemons: Information Disclosure and Fiscal Capacity

We study the optimal use of disclosure and fiscal backstops during financial crises. Providing information can reduce adverse selection in credit markets, but negative disclosures can also trigger inefficient bank runs. In our model, governments are thus forced to choose between runs and lemons. A fiscal backstop mitigates the cost of runs and allows a government to pursue a high disclosure strategy. Our model explains why governments with strong fiscal positions are more likely to run informative stress tests, and, paradoxically, how they can end up spending less than governments that are more fiscally constrained.
Recent hybrids recapitulate ancient hybrid outcomes

Genomic outcomes of hybridization depend on selection and recombination in hybrids. Whether these processes have similar effects on hybrid genome composition in contemporary hybrid zones versus ancient hybrid lineages is unknown. Here we show that patterns of introgression in a contemporary hybrid zone in Lycaeides butterflies predict patterns of ancestry in geographically adjacent, older hybrid populations. We find a particularly striking lack of ancestry from one of the hybridizing taxa, Lycaeides melissa, on the Z chromosome in both the old and contemporary hybrids. The same pattern of reduced L. melissa ancestry on the Z chromosome is seen in two other ancient hybrid lineages. More generally, we find that patterns of ancestry in old or ancient hybrids are remarkably predictable from contemporary hybrids, which suggests selection and recombination affect hybrid genomes in a similar way across disparate time scales and during distinct stages of speciation and species breakdown.
Neutron scattering studies of the actinides

Abstract The electronic structure of actinide materials presents a unique example of the interplay between localized and band electrons. Together with a variety of other techniques, especially magnetization and the Mossbauer effect, neutron studies have helped us to understand the systematics of many actinide compounds that order magnetically. A direct consequence of the localization of 5 f electrons is the spin-orbit coupling and subsequent spin-lattice interaction that often leads to strongly anisotropic behavior. The unusual phase transition in UO 2 , for example, arises from interactions between quadrupole moments. On the other hand, in the monopnictides and monochalcogenides, the anisotropy is more difficult to understand, but probably involves an interaction between actinide and anion wave functions. A variety of neutron experiments, including form-factor studies, critical scattering and measurements of the elementary excitations have now been performed, and the conceptual picture emerging from these studies will be discussed.
Widths of the K α 1 and K α 2 X-Ray Lines for Z > 50

A Cauchois-type transmission bent-crystal spectrometer has been used to measure the full width at half-maximum of the $K{\ensuremath{\alpha}}_{1}$ and $K{\ensuremath{\alpha}}_{2}$ x rays of 36 elements from $_{51}\mathrm{Sb}$ to $_{95}\mathrm{Am}$. The x-ray lines were fitted by folding a Lorentzian natural line shape with a Gaussian instrumental response and integrating over the detector-slit width. The present results are systematically somewhat higher than the values deduced from recent theoretical calculations of the radiative widths and the appropriate experimental fluorescent yields.
Network Reliability and Fault-Tolerance

This article begins with a discussion of network availability and performability, followed by an examination of survivable network design. It also covers the issues of fault detection, isolation, restoration, and preplanning. Keywords: network reliability; performability; capacity design; packet-switched network; fault detection; software attack
Starch: Uses of Native Starch

Native starch has a long history of use as a food source, but because of its abundance, nonfood applications have been developed. Available starches are mostly isolated from either corn, wheat, potato, or cassava. Starch is composed of two polymers of glucose: amylose and amylopectin. The ratio of amylose to amylopectin varies with the botanical source. Many applications of starch rely on rheological and textural properties that are influenced by its amylose and amylopectin content. Starch is used in many industrial products and its function ranges from being an adhesive, binder, flocculent, filler, and fermentation ingredient to being a viscosity modifier. The largest industrial user of starch is the paper industry. Currently, less than 30% of the starch produced in the United States and Europe goes into food. Starch serves many functions in food, but its primary function is to control viscosity.
Incompatibility, Product Attributes and Consumer Welfare: Evidence from ATMs

Incompatibility in market with network effects reduces consumers’ ability to “mix and match” components offered by different sellers, but can also spur changes in product attributes that might beneÞt consumers. In this paper, we estimate the effects of incompatibility on consumers in a classic hardware/software market: ATM cards and machines. We Þnd that while ATM fees ceteris paribus reduce the network beneÞt from other banks’ ATMs, a surge in ATM deployment accompanies the shift to surcharging. This is valuable to consumers and often completely offsets the harm from higher fees. The results suggest that policy discussions of incompatibility must consider not only its direct effect on consumers, but also its effect on product attributes.
The Welfare Losses from Price-Matching Policies

Several recent papers argue that price-matching policies raise equilibrium prices. We add to this literature by considering potential welfare losses, which have two sources: Harberger triangles from high prices and Posner rectangles from over-entry. We compare price-matching markets with entry to monopoly and price-matching markets without entry, and find that price matching with entry creates greater welfare losses than monopoly in markets with a low ratio of fixed to marginal cost. We illustrate this result using parameters from the US wholesale gasoline and air travel markets, and relate our model to price matching among NASDAQ market makers.
Tin Telluride (SnTe)

Publisher Summary The binary compound semiconductor tin telluride (SnTe) is isomorphous with rock salt. SnTe has direct interband optical transitions at the L point in the Brillouin zone. The band structure near the fundamental gap is more complicated than in the lead salts. For large-hole concentrations, one should observe a positive temperature coefficient of the fundamental gap. The temperature coefficient of the gap changes its sign from negative to positive with increasing hole concentration in the temperature region between 50 and 150 K. This chapter reviews the studies performed on the reflectivity of SnTe and analyzes the previous measurement works carried out on the near-normal reflectivity of polycrystalline SnTe over the photon-energy range 0.5–21 eV at room temperature, the absorption coefficient and the index of refraction of SnTe at 300 K over the photon-energy range between 0.14 and 0.64 eV, and the absorption spectra of crystalline SnTe films in the 2–120 eV region using synchrotron radiation at liquid-nitrogen temperature. The chapter further highlights an ellipsometry study of SnTe in the infrared and visible spectral regions and provides a list of values of n and k obtained from various references.
CONTEST DESIGN: AN EXPERIMENTAL INVESTIGATION

This paper experimentally compares the performance of four simultaneous lottery contests: a grand contest, two multiple prize settings (equal and unequal prizes), and a contest which consists of two subcontests. Consistent with the theory, the grand contest generates the highest effort levels among all simultaneous contests. In multiprize settings, equal prizes produce lower efforts than unequal prizes. The results also support the argument that joint contests generate higher efforts than an equivalent number of subcontests. Contrary to the theory, there is significant over-dissipation. This over-dissipation can be partially explained by strong endowment size effects. Subjects who receive higher endowments tend to over-dissipate, whereas such overdissipation disappears when the endowments are lower. This behavior is consistent with the predictions of a quantal response equilibrium. We also find that less risk-averse subjects over-dissipate more. (JEL C72, C91, D72)
Environmental Effects of Space Systems

The potential impacts of the U.S. Space Shuttle program and the proposed Satellite Power System on the earth's upper atmosphere and magnetosphere are discussed. Major impacts of these systems would occur from power transmission through space, the injection of rocket effluents and ablated materials into various regions of the upper atmosphere, and the actual presence of large structures in orbit. Possible effects include compositional changes in the atmosphere, an alteration of magnetospheric and plasmaspheric structure and dynamics, and a perturbation of Van Allen radiation belt stability. However, in light of current knowledge, the potential atmospheric effects of large space systems and their significance for the terrestrial environment should be regarded as uncertain.
Melt filaments in n+pn+ lateral bipolar ESD protection devices

Abstract Lateral bipolar n+pn+ devices, with thick field oxide (TFO) separating the collector and emitter, are often used in snapback mode as protection devices for MOS ESD circuit protection. ESD testing for human body model (HBM), machine model (MM) and charged device model (CDM) waveforms was performed on a family of TFO cells which varied the gate length (bipolar base width) as the experimental parameter. For MM and CDM, the data showed a dependence of withstand voltage on the gate length, indicating that longer gate lengths improve performance; while for HBM, withstand voltage was independent of the gate length. The devices exhibited failure modes that manifested as low-level current leakage. Failure analysis identified the current leakage sites as melt filaments primarily localized at the TFO ends. Filament distribution was seen to be a function of gate length for MM. Two possible mechanisms are presented to account for the observed filament distribution and follow-up experiments are suggested to test the validity of each.
Harvesting and seeding of stochastic populations: analysis and numerical approximation

We study an ecosystem of interacting species that are influenced by random environmental fluctuations. At any point in time, we can either harvest or seed (repopulate) species. Harvesting brings an economic gain while seeding incurs a cost. The problem is to find the optimal harvesting-seeding strategy that maximizes the expected total income from harvesting minus the cost one has to pay for the seeding of various species. In Hening et al. (J Math Biol 79(2):533-570, 2019b) we considered this problem when one has absolute control of the population (infinite harvesting and seeding rates are possible). In many cases, these approximations do not make biological sense and one must consider what happens when one, or both, of the seeding and harvesting rates are bounded. The focus of this paper is the analysis of these three novel settings: bounded seeding and infinite harvesting, bounded seeding and bounded harvesting, and infinite seeding and bounded harvesting. Even one dimensional harvesting problems can be hard to tackle. Once one looks at an ecosystem with more than one species analytical results usually become intractable. In order to gain information regarding the qualitative behavior of the system we develop rigorous numerical approximation methods. This is done by approximating the continuous time dynamics by Markov chains and then showing that the approximations converge to the correct optimal strategy as the mesh size goes to zero. By implementing these numerical approximations, we are able to gain qualitative information about how to best harvest and seed species in specific key examples. We are able to show through numerical experiments that in the single species setting the optimal seeding-harvesting strategy is always of threshold type. This means there are thresholds [Formula: see text] such that: (1) if the population size is 'low', so that it lies in [Formula: see text], there is seeding using the maximal seeding rate; (2) if the population size 'moderate', so that it lies in [Formula: see text], there is no harvesting or seeding; (3) if the population size is 'high', so that it lies in the interval [Formula: see text], there is harvesting using the maximal harvesting rate. Once we have a system with at least two species, numerical experiments show that constant threshold strategies are not optimal anymore. Suppose there are two competing species and we are only allowed to harvest or seed species 1. The optimal strategy of seeding and harvesting will involve lower and upper thresholds [Formula: see text] which depend on the density [Formula: see text] of species 2.
Notes on the Sociological Study of Language

The SSRC’s Committee on Sociolinguistics (1963–1979) was formed to explore how the nascent interdisciplinary field of sociolinguistics could deepen scholarly understanding of the intersection of language with social, cultural, and political questions. In this 1963 piece, John Useem, a committee member, explains how “developing the sociological study of language” would advance social science. He emphasizes the potential contribution to social knowledge through research on how language is used across cultural contexts and social divides of class, geography, race, and ethnicity.
Brain regional gene expression network analysis identifies unique interactions between chronic ethanol exposure and consumption.

Progressive increases in ethanol consumption is a hallmark of alcohol use disorder (AUD). Persistent changes in brain gene expression are hypothesized to underlie the altered neural signaling producing abusive consumption in AUD. To identify brain regional gene expression networks contributing to progressive ethanol consumption, we performed microarray and scale-free network analysis of expression responses in a C57BL/6J mouse model utilizing chronic intermittent ethanol by vapor chamber (CIE) in combination with limited access oral ethanol consumption. This model has previously been shown to produce long-lasting increased ethanol consumption, particularly when combining oral ethanol access with repeated cycles of intermittent vapor exposure. The interaction of CIE and oral consumption was studied by expression profiling and network analysis in medial prefrontal cortex, nucleus accumbens, hippocampus, bed nucleus of the stria terminalis, and central nucleus of the amygdala. Brain region expression networks were analyzed for ethanol-responsive gene expression, correlation with ethanol consumption and functional content using extensive bioinformatics studies. In all brain-regions studied the largest number of changes in gene expression were seen when comparing ethanol naive mice to those exposed to CIE and drinking. In the prefrontal cortex, however, unique patterns of gene expression were seen compared to other brain-regions. Network analysis identified modules of co-expressed genes in all brain regions. The prefrontal cortex and nucleus accumbens showed the greatest number of modules with significant correlation to drinking behavior. Across brain-regions, however, many modules with strong correlations to drinking, both baseline intake and amount consumed after CIE, showed functional enrichment for synaptic transmission and synaptic plasticity.
Multidimensional hydrogel models reveal endothelial network angiocrine signals increase glioblastoma cell number, invasion, and temozolomide resistance

Glioblastoma (GBM) is the most common primary malignant brain tumor. The tissue microenvironment adjacent to vasculature, termed the perivascular niche, has been implicated in promoting biological processes involved in glioblastoma progression such as invasion, proliferation, and therapeutic resistance. However, the exact nature of the cues that support tumor cell aggression in this niche is largely unknown. Soluble angiocrine factors secreted by tumor-associated vasculature have been shown to support such behaviors in other cancer types. Here, we exploit macroscopic and microfluidic gelatin hydrogel platforms to profile angiocrine factors secreted by self-assembled endothelial networks and evaluate their relevance to glioblastoma biology. Aggregate angiocrine factors support increases in U87-MG cell number, migration, and therapeutic resistance to temozolomide. We also identify a novel role for TIMP1 in facilitating glioblastoma tumor cell migration. Overall, this work highlights the use of multidimensional hydrogel models to evaluate the role of angiocrine signals in glioblastoma progression.
Negative-energy contributions to transition amplitudes in heliumlike ions

We derive the leading term in an aZ expansion for the negative-energy ~virtual electron-positron pair! contributions to the transition amplitudes of heliumlike ions. The resulting expressions allow us to perform a general analysis of the negative-energy contributions to electric- and magnetic-multipole transition amplitudes. We observe a strong dependence on the choice of the zeroth-order Hamiltonian, which defines the negativeenergy spectrum. We show that for transitions between states with different values of total spin, the negativeenergy contributions calculated in a Coulomb basis vanish in the leading order while they remain finite in a Hartree basis. The ratio of negative-energy contributions to the total transition amplitudes for some of nonrelativistically forbidden transitions is shown to be of order 1/ Z. In the particular case of the magnetic-dipole transition 3 3 S1!2 3 S1 , we demonstrate that the neglect of negative-energy contributions, in an otherwise exact no-pair calculation, would lead one to underestimate the decay rate in helium by a factor of 1.5 in calculations using a Hartree basis and by a factor of 2.9 using a Coulomb basis. Finally, we tabulate revised values of the line strength S for the magnetic-quadrupole ( M 2) transition 2 3 P2!1 1 S0 . These values include negative-energy contributions from higher partial waves, which were neglected in our previous calculations. @S1050-2947~98!03512-4#
Constrained Thompson Sampling for Real-Time Electricity Pricing With Grid Reliability Constraints

We consider the problem of an electricity aggregator attempting to learn customers’ electricity usage models while implementing a load shaping program by means of broadcasting dispatch signals in real-time. We adopt a multi-armed bandit problem formulation to account for the stochastic and unknown nature of customers’ responses to dispatch signals. We propose a constrained Thompson sampling heuristic, Con-TS-RTP, as a solution to the load shaping problem of the electricity aggregator attempting to influence customers’ usage to match various desired demand profiles (i.e., to reduce demand at peak hours, integrate more intermittent renewable generation, track a desired daily load profile, etc). The proposed Con-TS-RTP heuristic accounts for day-varying target load profiles (i.e., multiple target load profiles reflecting renewable forecasts and desired demand patterns) and takes into account the operational constraints of a distribution system to ensure that customers receive adequate service and to avoid potential grid failures. We provide a discussion on the regret bounds for our algorithm as well as a discussion on the operational reliability of the distribution system’s constraints being upheld throughout the learning process.
Response to a comment on Dessert et al. "The dark matter interpretation of the 3.5 keV line is inconsistent with blank-sky observations"

Abstract The dark matter explanation of the 3.5 keV line is strongly disfavored by our work in Dessert et al. (2020). Boyarsky et al. (2004) questions that conclusion: modeling additional background lines is claimed to weaken the limit sufficiently to re-allow a dark matter interpretation. We respond as follows. (1) A more conservative limit is obtained by modeling additional lines; this point appeared in its entirety in our work in Dessert et al. (2020), though we also showed that the inclusion of such lines is not necessary. (2) Despite suggestions in Boyarsky et al. (2004), even the more conservative limits strongly disfavor a decaying dark matter origin of the 3.5 keV line.