cssi/SciSciGPT-SciSciNet huggingface dataset:
Genetic deletion of Sphk2 confers protection against Pseudomonas aeruginosa mediated differential expression of genes related to virulent infection and inflammation in mouse lung

Pseudomonas aeruginosa (PA) is an opportunistic Gram-negative bacterium that causes serious life threatening and nosocomial infections including pneumonia. PA has the ability to alter host genome to facilitate its invasion, thus increasing the virulence of the organism. Sphingosine-1- phosphate (S1P), a bioactive lipid, is known to play a key role in facilitating infection. Sphingosine kinases (SPHK) 1&2 phosphorylate sphingosine to generate S1P in mammalian cells. We reported earlier that Sphk2−/− mice offered significant protection against lung inflammation, compared to wild type (WT) animals. Therefore, we profiled the differential expression of genes between the protected group of Sphk2−/− and the wild type controls to better understand the underlying protective mechanisms related to the Sphk2 deletion in lung inflammatory injury. Whole transcriptome shotgun sequencing (RNA-Seq) was performed on mouse lung tissue using NextSeq 500 sequencing system. Two-way analysis of variance (ANOVA) analysis was performed and differentially expressed genes following PA infection were identified using whole transcriptome of Sphk2−/− mice and their WT counterparts. Pathway (PW) enrichment analyses of the RNA seq data identified several signaling pathways that are likely to play a crucial role in pneumonia caused by PA such as those involved in: 1. Immune response to PA infection and NF-κB signal transduction; 2. PKC signal transduction; 3. Impact on epigenetic regulation; 4. Epithelial sodium channel pathway; 5. Mucin expression; and 6. Bacterial infection related pathways. Our genomic data suggests a potential role for SPHK2 in PA-induced pneumonia through elevated expression of inflammatory genes in lung tissue. Further, validation by RT-PCR on 10 differentially expressed genes showed 100% concordance in terms of vectoral changes as well as significant fold change. Using Sphk2−/− mice and differential gene expression analysis, we have shown here that S1P/SPHK2 signaling could play a key role in promoting PA pneumonia. The identified genes promote inflammation and suppress others that naturally inhibit inflammation and host defense. Thus, targeting SPHK2/S1P signaling in PA-induced lung inflammation could serve as a potential therapy to combat PA-induced pneumonia.
Proton Light Yield of Fast Plastic Scintillators for Neutron Imaging

Plastic, organic scintillators have been tailored in composition to achieve an ultrafast temporal response, thereby enabling the design and development of fast neutron detection systems with high timing resolution. Eljen Technology’s plastic, organic scintillators—EJ-230, EJ-232, and EJ-232Q—are prospective candidates for use in emerging neutron imaging systems, where fast timing is paramount. To support the neutron response characterization of these materials, the relative proton light yields (PLYs) of EJ-230, EJ-232, and EJ-232Q were measured at the 88-Inch Cyclotron at the Lawrence Berkeley National Laboratory. Using a broad-spectrum neutron source and a double-time-of-flight technique, the PLY relations were obtained over a proton recoil energy range of approximately 300 keV to 4 MeV. The EJ-230, EJ-232, and EJ-232Q scintillators exhibited similar PLY relations to each other and to other plastic scintillators with the same polymer base material. A comparison of the relative PLY of different sized cylindrical EJ-232 and EJ-232Q scintillators also revealed consistent results. This article provides key input data for the realistic computational modeling of neutron detection technologies employing these materials, thereby supporting new capabilities in near-field radionuclide detection for national security applications.
Dynamic and Programmable Cellular-Scale Granules Enable Tissue-like Materials

Summary Living tissues are an integrated, multiscale architecture consisting of dense cellular ensembles and extracellular matrices (ECMs). The cells and ECMs cooperate to enable specialized mechanical properties and dynamic responsiveness. However, the mechanical properties of living tissues are difficult to replicate. A particular challenge is identification of a cell-like synthetic component, which is tightly integrated with its matrix and also responsive to external stimuli. Here, we demonstrate that cellular-scale hydrated starch granules, an underexplored component in materials science, can turn conventional hydrogels into tissue-like materials when composites are formed. By using several synchrotron-based X-ray techniques, we reveal the mechanically induced organization and training dynamics of the starch granules in the hydrogel matrix. These dynamic behaviors enable multiple tissue-like properties such as programmability, anisotropy, strain-stiffening, mechanochemistry, and self-healability.
The Factorization Problem in Jackiw-Teitelboim Gravity

In this note we study the 1 + 1 dimensional Jackiw-Teitelboim gravity in Lorentzian signature, explicitly constructing the gauge-invariant classical phase space and the quantum Hilbert space and Hamiltonian. We also semiclassically compute the Hartle-Hawking wave function in two different bases of this Hilbert space. We then use these results to illustrate the gravitational version of the factorization problem of AdS/CFT: the Hilbert space of the two-boundary system tensor-factorizes on the CFT side, which appears to be in tension with the existence of gauge constraints in the bulk. In this model the tension is acute: we argue that JT gravity is a sensible quantum theory, based on a well-defined Lorentzian bulk path integral, which has no CFT dual. In bulk language, it has wormholes but it does not have black hole microstates. It does however give some hint as to what could be added to rectify these issues, and we give an example of how this works using the SYK model. Finally we suggest that similar comments should apply to pure Einstein gravity in 2 + 1 dimensions, which we’d then conclude also cannot have a CFT dual, consistent with the results of Maloney and Witten.
Cumulative Effects of Social Stress on Reward-Guided Actions and Prefrontal Cortical Activity.

Abstract Background When exposed to chronic social stress, animals display behavioral changes that are relevant to depressive-like phenotypes. However, the cascading relationship between incremental stress exposure and neural dysfunctions over time remains incompletely understood. Methods We characterized the longitudinal effect of social defeat on goal-directed actions and prefrontal cortical activity in mice using a novel head-fixed sucrose preference task and two-photon calcium imaging. Results Behaviorally, stress-induced loss of reward sensitivity intensifies over days. Motivational anhedonia, the failure to translate positive reinforcements into future actions, requires multiple sessions of stress exposure to become fully established. For neural activity, individual layer 2/3 pyramidal neurons in the cingulate and medial secondary motor subregions of the medial prefrontal cortex have heterogeneous responses to stress. Changes in ensemble activity differ significantly between susceptible and resilient mice after the first defeat session and continue to diverge following successive stress episodes before reaching persistent abnormal levels. Conclusions Collectively, these results demonstrate that the cumulative impact of an ethologically relevant stress can be observed at the level of cellular activity of individual prefrontal neurons. The distinct neural responses associated with resilience versus susceptibility suggests the hypothesis that the negative impact of social stress is neutralized in resilient animals, in part through an adaptive reorganization of prefrontal cortical activity.
Systematic Integration of Structural and Functional Data into Multi-scale Models of Mouse Primary Visual Cortex.

Summary Structural rules underlying functional properties of cortical circuits are poorly understood. To explore these rules systematically, we integrated information from extensive literature curation and large-scale experimental surveys into a data-driven, biologically realistic simulation of the awake mouse primary visual cortex. The model was constructed at two levels of granularity, using either biophysically detailed or point neurons. Both variants have identical network connectivity and were compared to each other and to experimental recordings of visual-driven neural activity. While tuning these networks to recapitulate experimental data, we identified rules governing cell-class-specific connectivity and synaptic strengths. These structural constraints constitute hypotheses that can be tested experimentally. Despite their distinct single-cell abstraction, both spatially extended and point models perform similarly at the level of firing rate distributions for the questions we investigated. All data and models are freely available as a resource for the community.
Reasonable Doubt: Experimental Detection of Job‐Level Employment Discrimination

This paper develops methods for detecting discrimination by individual employers using correspondence experiments that send fictitious resumes to real job openings. We establish identification of higher moments of the distribution of job-level callback rates as a function of the number of resumes sent to each job and propose shape-constrained estimators of these moments. Applying our methods to three experimental datasets, we find striking job-level heterogeneity in the extent to which callback probabilities differ by race or sex. Estimates of higher moments reveal that while most jobs barely discriminate, a few discriminate heavily. These moment estimates are then used to bound the share of jobs that discriminate and the posterior probability that each individual job is engaged in discrimination. In a recent experiment manipulating racially distinctive names, we find that at least 85% of jobs that contact both of two white applications and neither of two black applications are engaged in discrimination. To assess the potential value of our methods for regulators, we consider the accuracy of decision rules for investigating suspicious callback behavior in various experimental designs under a simple two-type model that rationalizes the experimental data. Though we estimate that only 17% of employers discriminate on the basis of race, we find that an experiment sending 10 applications to each job would enable detection of 7-10% of discriminatory jobs while yielding Type I error rates below 0.2%. A minimax decision rule acknowledging partial identification of the distribution of callback rates yields only slightly fewer investigations than a Bayes decision rule based on the two-type model. These findings suggest illegal labor market discrimination can be reliably monitored with relatively small modifications to existing correspondence designs.
New candidates for regulated gene integrity revealed through precise mapping of integrative genetic elements.

Integrative genetic elements (IGEs) are mobile multigene DNA units that integrate into and excise from host bacterial genomes. Each IGE usually targets a specific site within a conserved host gene, integrating in a manner that preserves target gene function. However, a small number of bacterial genes are known to be inactivated upon IGE integration and reactivated upon excision, regulating phenotypes of virulence, mutation rate, and terminal differentiation in multicellular bacteria. The list of regulated gene integrity (RGI) cases has been slow-growing because IGEs have been challenging to precisely and comprehensively locate in genomes. We present software (TIGER) that maps IGEs with unprecedented precision and without attB site bias. TIGER uses a comparative genomic, ping-pong BLAST approach, based on the principle that the IGE integration module (i.e. its int-attP region) is cohesive. The resultant IGEs from 2168 genomes, along with integrase phylogenetic analysis and gene inactivation tests, revealed 19 new cases of genes whose integrity is regulated by IGEs (including dut, eccCa1, gntT, hrpB, merA, ompN, prkA, tqsA, traG, yifB, yfaT and ynfE), as well as recovering previously known cases (in sigK, spsM, comK, mlrA and hlb genes). It also recovered known clades of site-promiscuous integrases and identified possible new ones.
Machine Learning the Phenomenology of COVID-19 From Early Infection Dynamics

We present a robust data-driven machine learning analysis of the COVID-19 pandemic from its early infection dynamics, specifically infection counts over time. The goal is to extract actionable public health insights. These insights include the infectious force, the rate of a mild infection becoming serious, estimates for asymtomatic infections and predictions of new infections over time. We focus on USA data starting from the first confirmed infection on January 20 2020. Our methods reveal significant asymptomatic (hidden) infection, a lag of about 10 days, and we quantitatively confirm that the infectious force is strong with about a 0.14% transition from mild to serious infection. Our methods are efficient, robust and general, being agnostic to the specific virus and applicable to different populations or cohorts.
Poisson Kernel-Based Clustering on the Sphere: Convergence Properties, Identifiability, and a Method of Sampling

Spherical or directional data arise in many applications of interest. Furthermore, many nondirectional datasets can be usefully re-expressed in the form of directions and analyzed as spherical data...
Randomization Tests for Weak Null Hypotheses in Randomized Experiments

The Fisher randomization test (FRT) is appropriate for any test statistic, under a sharp null hypothesis that can recover all missing potential outcomes. However, it is often sought after to test a...
Leader Value Added : Assessing the Growth Contribution of Individual National Leaders

Previous literature suggests that leaders matter for growth in general. This paper asks which leaders matter and develops a methodology to estimate the growth contribution of individual leaders and calculate its precision. The findings show that few leaders have statistically significant contributions; it is difficult to know who is good for growth and who is not. The paper also finds that the most intuitive estimate of a leader's contribution -- the average growth rate during tenure -- is largely useless for measuring his or her true contribution. Consequently, many leaders with statistically significant growth effects are surprises. Moreover, leaders in non-democratic countries are no more likely to be statistically significant than leaders in democratic ones.
Assessment of enrollment characteristics for Children’s Oncology Group (COG) upfront therapeutic clinical trials 2004-2015

Background Improvements in pediatric cancer survival are attributed to cooperative clinical trials. Under-representation of specific demographic groups has been described in adult and pediatric cancer trials and poses a threat to the generalizability of results. An evaluation of data provided by the Children’s Oncology Group (COG) of upfront trial enrollment for US patients 0 to 29 years old between 2004 and 2015 was performed. Methods US cancer cases were estimated using incidence data and US population estimates from the Surveillance, Epidemiology, and End Results Program and compared to observed COG cases. Percent enrollment and standardized ratios of enrollment were calculated across demographic, disease, and socioeconomic groups. The COG website was utilized to quantify available trials and assess age eligibility. Results 19.9% of estimated US cancer patients age 0 to 19 years enrolled on COG trials. Younger patients were more represented across diseases and races/ethnicities. Patients with hematologic malignancies were more represented compared to solid and central nervous system (CNS) tumors. Conclusion COG trial enrollment rates are declining when compared to previously published data, potentially from challenges in pediatric drug development, difficulty designing feasible trials for highly curable diagnoses, and issues ensuring trial availability for the heterogeneous group of solid and CNS tumors. Though racial/ethnic groups and county-level socioeconomic factors were proportionally represented, under representation of the adolescent/young adult (AYA) population and younger patients with solid and CNS tumors remains a concern. Targeted efforts should focus on these subgroups and further research should evaluate AYA enrollment rates across all available trials.
Expanding the domain of policy-relevant scholarship in the social sciences

In this paper the author argues that social scientists need to do more to provide policy-relevant research. Rapid technological and economic change raise new issues about how policy should adjust that are not adequately addressed by older and narrower approaches. The author suggests two ways in which the domain of policy-relevant scholarship can be expanded. First, social scientists should be more flexible about the kinds of data they use and the ways they use them. Preliminary data can suggest new hypotheses, which can widen debate, and ethnographic and other qualitative methods can uncover patterns of behaviour invisible in quantitative sources. Second, social theories, concepts and ideas should play a greater role in the policy arena, shaping the way policy actors think about how the world works.
Paying the Price for a Broken Healthcare System: Rethinking Employment, Labor, and Work in a Post-Pandemic World

Even before the word pandemic reentered the lexicon, pressures stemming from institutional and technological change challenged policymakers and provider organizations to rethink core features of the manner in which we deliver healthcare. This essay introduces a special issue devoted to the consequences of change on the healthcare sector’s varied stakeholders. It does so in the context of our eventual, post-coronavirus reemergence and a renewed interest in remaking the healthcare system in light of its obvious deficiencies. Towards that end, we introduce the five papers composing this special issue, each of which informs the ways that change actually transpires in healthcare organizations and systems.
Policy sciences perspectives on implementation processes

Implementation, from which flows operational policy, is an integral part of the policymaking process. This phenomenon is examined briefly as a socio-political process, an administrative task, a follow-on from systematic analysis, a problem in the diffusion and utilization of knowledge, and a basic capacity which is differentially distributed among organizations and subject to deliberate change. A three-dimensional framework for assessing the nature of implementation tasks and for making strategic choices in planning implementation is proposed and illustrated. Finally, implementation processes in a federalistic system are described as requiring multi-level participation of four classes of participants: administrative-bureaucratic, political leadership, rational-analytic and constituent elites. A variety of functions must be performed at federal, regional, and local levels to assure policy execution consistent with both policy designs and local contingencies.
3 – Heat Exchangers

This chapter provides a review of the methods used in the thermal analysis of heat exchangers. Equipment used in double-pipe (hairpin), shell-and-tube, and plate heat exchangers is described. The overall heat-transfer coefficient, fouling factors, LMTD (logarithmic mean temperature difference) correction factor, and heat-exchanger effectiveness are introduced and examples of their use are given. The thermal analysis of a double-pipe heat exchanger is illustrated in detail, as is the thermal rating of a shell-and-tube exchanger. Alternate approaches for providing fouling allowance in heat exchanger design are also discussed.
Chapter 5 – Ecosystem Change

Impacts of climate change on any individual species can cascade through biological systems, affecting other species, many of which may be responding to climate change themselves. These complex ecosystem impacts are among the most important in climate change biology because they impact the services these ecosystems deliver for human well-being and livelihoods. Impacts on tropical forests, marine fisheries, coral reefs and other systems are explored.
9 – Static Induction Devices

Publisher Summary This chapter describes several devices from the static induction family such as static induction transistor (SIT), static induction diode (SID), static induction thyristor, lateral punch-through transistor (LPTT), static induction transistor logic (SITL), static induction MOS transistor (SIMOS), and space charge limiting load (SCLL). The CMT conductivity modulation transistor has a unique ability of controlling ac current flow without a significant distortion of the sinusoidal waveforms of flowing current. The bipolar mode of operation of the SIT can also be used to obtain diodes with low forward voltage drop and negligible carrier storage effect. Fabrications of SI transistors usually require very sophisticated technology. It is much simpler to fabricate a lateral punch-through transistor, which operates on the same principle and has similar characteristics. The SI transistor can also be used instead of a Schottky diode to protect a bipolar junction transistor against saturation. Power MOS transistors are being used for fast switching power supplies and for switching power converters. They can be driven with relatively small power, and switching frequencies could be very high.
Revisiting the Classical View of Benefit-Based Taxation

This paper explores how the persistently popular "classical" logic of bene…t based taxation, in which an individual’s bene…t from public goods is tied to his or her income-earning ability, can be incorporated into modern optimal tax theory. If Lindahl’s methods are applied to that view of bene…ts, …rst-best optimal policy can be characterized analytically as depending on a few potentially estimable statistics, in particular the coe¢ cient of complementarity between public goods and innate talent. Constrained optimal policy with a Pareto-e¢ cient objective that strikes a balance–controlled by a single parameter–between this principle and the familiar utilitarian criterion can be simulated using conventional constraints and methods. A wide range of optimal policy outcomes can result, including those that match well several features of existing policies. To the extent that such an objective re‡ects the mixed normative reasoning behind prevailing
Political monetary cycles and a de facto ranking of central bank independence

This paper examines the extent to which monetary policy is manipulated for political purposes by testing for the presence of political monetary cycles between 1972 and 2001. This is the first study of its kind to include not only advanced countries but also a large sample of developing nations where these cycles are more likely to exist. We estimate panel regressions of a monetary policy indicator on an election dummy and control variables. We do not find evidence of political monetary cycles in advanced countries but find strong evidence in developing nations. Based on our results, we construct a new de facto ranking of central bank independence derived from the extent to which monetary policy varies with the election cycle. Our ranking of CBI is therefore based on the behavior of central banks during election cycles when their independence is likely to be challenged or their lack of independence is likely to be revealed. The ranking also avoids well-known problems with existing measures of central bank independence.
A fault-tolerance shim for serverless computing

Serverless computing has grown in popularity in recent years, with an increasing number of applications being built on Functions-as-a-Service (FaaS) platforms. By default, FaaS platforms support retry-based fault tolerance, but this is insufficient for programs that modify shared state, as they can unwittingly persist partial sets of updates in case of failures. To address this challenge, we would like atomic visibility of the updates made by a FaaS application. In this paper, we present aft, an atomic fault tolerance shim for serverless applications. aft interposes between a commodity FaaS platform and storage engine and ensures atomic visibility of updates by enforcing the read atomic isolation guarantee. aft supports new protocols to guarantee read atomic isolation in the serverless setting. We demonstrate that aft introduces minimal overhead relative to existing storage engines and scales smoothly to thousands of requests per second, while preventing a significant number of consistency anomalies.
Singular limits of sign-changing weighted eigenproblems

Consider the eigenvalue problem generated by a fixed differential operator with a sign-changing weight on the eigenvalue term. We prove that as the negative part of the weight is rescaled towards negative infinity on some subregion, the spectrum converges to that of the original problem restricted to the complementary region. On the interface between the regions the limiting problem acquires Dirichlet-type boundary conditions. Our main theorem concerns eigenvalue problems for sign-changing bilinear forms on Hilbert spaces. We apply our results to a wide range of PDEs: second and fourth order equations with both Dirichlet and Neumann-type boundary conditions, and a problem where the eigenvalue appears in both the equation and the boundary condition.
Public infrastructure investments, productivity and welfare in fixed geographic areas

Abstract Measures of the value of public investments are critical inputs into the policy process, and aggregate production and cost functions have become the dominant methods of evaluating these benefits. This paper examines the limitations of these approaches in light of applied production and spatial equilibrium theories. A spatial equilibrium model of an economy with nontraded, localized public goods like infrastructure is proposed, and a method for identifying the role of public capital in firm production and household preferences is derived. Empirical evidence from a sample of large US cities suggests that public capital provides significant marginal benefits. But the marginal productivity of public capital is low, and aggregate city willingness to pay for large increases in public capital is less than their cost. The paper concludes with a brief discussion of the political economy of urban infrastructure investment.
FDI, exports, and GDP in East and Southeast Asia—Panel data versus time-series causality analyses

Abstract Using time-series and panel data from 1986 to 2004, this paper examines the Granger causality relations between GDP, exports, and FDI among China, Korea, Taiwan, Hong Kong, Singapore, Malaysia, Philippines, and Thailand, the eight rapidly developing East and Southeast Asian economies. After reviewing the current literature and testing the properties of individual time-series data, we estimate the VAR of the three variables to find various Granger causal relations for each of the eight economies. We found each country has different causality relations and does not yield general rules. We then construct the panel data of the three variables for the eight economies as a group and then use the fixed effects and random effects approaches to estimate the panel data VAR equations for Granger causality tests. The panel data causality results reveal that FDI has unidirectional effects on GDP directly and also indirectly through exports, and there also exists bidirectional causality between exports and GDP for the group. Our results indicate that the panel data causality analysis has superior results over the time-series causality analysis. Economic and policy implications of our analyses are then explored in the conclusions.
Cognitive and Structural Antecedents of Innovation: A Large-Sample Study

This paper studies how cognitive and structural antecedents affect adaptation to disruptive innovations. We do so by analyzing how video game firms adapted to the free-to-play business model around...
Gender Differences in the Effects of Support Exchanges on Self-Esteem and Mastery for Mid- to Late-Life Adults

Applying social psychological theories of social exchange and gender socialization perspectives, we assess gender differences in the effects of receiving and giving social support on self-esteem an...
CD56 regulates human NK cell cytotoxicity through Pyk2

Human natural killer (NK) cells are defined as CD56+CD3-. Despite its ubiquitous expression on human NK cells the role of CD56 (NCAM) in human NK cell cytotoxic function has not been defined. In non-immune cells, NCAM can induce signaling, mediate adhesion, and promote exocytosis through interactions with focal adhesion kinase (FAK). Here we demonstrate that deletion of CD56 on the NK92 cell line leads to impaired cytotoxic function. CD56-knockout (KO) cells fail to polarize during immunological synapse (IS) formation and have severely impaired exocytosis of lytic granules. Phosphorylation of the FAK family member Pyk2 at tyrosine 402 is decreased in NK92 CD56-KO cells, demonstrating a functional link between CD56 and signaling in human NK cells. Cytotoxicity, lytic granule exocytosis, and the phosphorylation of Pyk2 are rescued by the reintroduction of CD56. These data highlight a novel functional role for CD56 in stimulating exocytosis and promoting cytotoxicity in human NK cells.
Arcjet Ablation of Stony and Iron Meteorites

A test campaign was conducted placing meteorites in the 60 MW plasma Arcjet Interaction Heating Facility at NASA Ames Research Center, with the aim to achieve flight-relevant conditions for asteroid impacts in Earth's atmosphere and to provide insight into how meteoritic materials respond to extreme entry heating environments. The test conditions at heat flux of 4000 W/m2 and 140 kPa stagnation pressure are comparable to those experienced by a 30-meter diameter asteroid moving at 20 km/s velocity at 65 km altitude in the Earth's atmosphere. Test objects were a stony type H5 ordinary chondrite (Tamdakht) and an iron type IAB-MG meteorite (Campo Del Cielo), and included the terrestrial analogs Dense Flood Basalt and Fused Silica. All samples were exposed for only a few seconds in the plasma stream. Significant melt flow and vaporization was observed for both the stony and iron meteorites during exposure. Mass loss from spallation of fragments was also observed. Vapor emitted atomic lines from alkali metals and iron, but did not emit the expected MgO molecular band emissions. The meteoritic melts flowed more rapidly, indicating lower viscosity, than those of Fused Silica. The surface recession was mapped. The effective heat of ablation derived from this showed that ablation under these conditions occurred in the melt-dominated regime. Ablation parameters have an effect on ground damage estimates. A bias in ablation parameters towards the melt-dominated regime would imply that impacting asteroids survive to lower altitude, and therefore could possibly have airbursts with a larger ground damage footprint.
New analysis pipeline for high-throughput domain–peptide affinity experiments improves SH2 interaction data

Protein domain interactions with short linear peptides, such as those of the Src homology 2 (SH2) domain with phosphotyrosine-containing peptide motifs (pTyr), are ubiquitous and important to many biochemical processes of the cell. The desire to map and quantify these interactions has resulted in the development of high-throughput (HTP) quantitative measurement techniques, such as microarray or fluorescence polarization assays. For example, in the last 15 years, experiments have progressed from measuring single interactions to covering 500,000 of the 5.5 million possible SH2–pTyr interactions in the human proteome. However, high variability in affinity measurements and disagreements about positive interactions between published data sets led us here to reevaluate the analysis methods and raw data of published SH2–pTyr HTP experiments. We identified several opportunities for improving the identification of positive and negative interactions and the accuracy of affinity measurements. We implemented model-fitting techniques that are more statistically appropriate for the nonlinear SH2–pTyr interaction data. We also developed a method to account for protein concentration errors due to impurities and degradation or protein inactivity and aggregation. Our revised analysis increases the reported affinity accuracy, reduces the false-negative rate, and increases the amount of useful data by adding reliable true-negative results. We demonstrate improvement in classification of binding versus nonbinding when using machine-learning techniques, suggesting improved coherence in the reanalyzed data sets. We present revised SH2–pTyr affinity results and propose a new analysis pipeline for future HTP measurements of domain–peptide interactions.
From Arguments to Key Points: Towards Automatic Argument Summarization

Generating a concise summary from a large collection of arguments on a given topic is an intriguing yet understudied problem. We propose to represent such summaries as a small set of talking points, termed key points, each scored according to its salience. We show, by analyzing a large dataset of crowd-contributed arguments, that a small number of key points per topic is typically sufficient for covering the vast majority of the arguments. Furthermore, we found that a domain expert can often predict these key points in advance. We study the task of argument-to-key point mapping, and introduce a novel large-scale dataset for this task. We report empirical results for an extensive set of experiments with this dataset, showing promising performance.
X-ray evidence for electron-ion equilibrium and ionization nonequilibrium in Young supernova remnants

X-ray emission up to 25 keV from the supernova remnants Cas A and Tycho has been detected with the A-2 spectroscopy experiment on HEAO 1. The spectra must include continuum components with effective temperature of about 10 to the 8th K which could arise from optically thin plasmas in the collisionless shock fronts. This is the first indication of electron-ion temperature equilibrium in the expanding shell of young remnants. The equivalent widths of the K-alpha and K-beta iron line blends in Cas A have also been measured and it is found that their ratio is not compatible with the measured X-ray temperature in the collisional ionization equilibrium model. Finally, an unsuccessful search has been conducted for hard X-ray pulsars in both remnants.
A Modified Random Phase Approximation of Polyelectrolyte Solutions

We compute the phase diagrams of salt-free polyelectrolyte solutions, using a modified Debye−Huckel approach. We introduce the chain connectivity via the random phase approximation with three modifications. First, we modify the electrostatic potential at short distances to include a boundary on the electrostatic attractions at the distance of closest approach between charges, which is important in semidilute solutions. This modification is shown to act as a hard core contribution in solutions of simple electrolytes. Second, we introduce a cutoff on the integration of the modes of wavelength smaller than the size over which the electrostatic attractions cannot be linearized and strongly perturbed chain are expected. A concentration-dependent cutoff is shown to be essential to predict physically reasonable phase diagrams. Third, ion condensation is included self-consistently. The modification does not give correct phase diagrams without the concentration-dependent cutoff. The combined modifications give pha...
Visual Response Characteristics in Lateral and Medial Subdivisions of the Rat Pulvinar.

Abstract The pulvinar is a higher-order thalamic relay and a central component of the extrageniculate visual pathway, with input from the superior colliculus and visual cortex and output to all of visual cortex. Rodent pulvinar, more commonly called the lateral posterior nucleus (LP), consists of three highly-conserved subdivisions, and offers the advantage of simplicity in its study compared to more subdivided primate pulvinar. Little is known about receptive field properties of LP, let alone whether functional differences exist between different LP subdivisions, making it difficult to understand what visual information is relayed and what kinds of computations the pulvinar might support. Here, we characterized single-cell response properties in two V1 recipient subdivisions of rat pulvinar, the rostromedial (LPrm) and lateral (LPl), and found that a fourth of the cells were selective for orientation, compared to half in V1, and that LP tuning widths were significantly broader. Response latencies were also significantly longer and preferred size more than three times larger on average than in V1; the latter suggesting pulvinar as a source of spatial context to V1. Between subdivisons, LPl cells preferred higher temporal frequencies, whereas LPrm showed a greater degree of direction selectivity and pattern motion detection. Taken together with known differences in connectivity patterns, these results suggest two separate visual feature processing channels in the pulvinar, one in LPl related to higher speed processing which likely derives from superior colliculus input, and the other in LPrm for motion processing derived through input from visual cortex. Significance Statement The pulvinar has a perplexing role in visual cognition as no clear link has been found between the functional properties of its neurons and behavioral deficits that arise when it is damaged. The pulvinar, called the lateral posterior nucleus (LP) in rats, is a higher order thalamic relay with input from the superior colliculus and visual cortex and output to all of visual cortex. By characterizing single-cell response properties in anatomically distinct subdivisions we found two separate visual feature processing channels in the pulvinar, one in lateral LP related to higher speed processing which likely derives from superior colliculus input, and the other in rostromedial LP for motion processing derived through input from visual cortex.
Counting Perfect Matchings and the Eight-Vertex Model

We study the approximation complexity of the partition function of the eight-vertex model on general 4-regular graphs. For the first time, we relate the approximability of the eight-vertex model to the complexity of approximately counting perfect matchings, a central open problem in this field. Our results extend those in [Jin-Yi Cai et al., 2018]. In a region of the parameter space where no previous approximation complexity was known, we show that approximating the partition function is at least as hard as approximately counting perfect matchings via approximation-preserving reductions. In another region of the parameter space which is larger than the region that is previously known to admit Fully Polynomial Randomized Approximation Scheme (FPRAS), we show that computing the partition function can be reduced to counting perfect matchings (which is valid for both exact and approximate counting). Moreover, we give a complete characterization of nonnegatively weighted (not necessarily planar) 4-ary matchgates, which has been open for several years. The key ingredient of our proof is a geometric lemma. We also identify a region of the parameter space where approximating the partition function on planar 4-regular graphs is feasible but on general 4-regular graphs is equivalent to approximately counting perfect matchings. To our best knowledge, these are the first problems that exhibit this dichotomic behavior between the planar and the nonplanar settings in approximate counting.
Experimental Design in Two-Sided Platforms: An Analysis of Bias

We develop an analytical framework to study experimental design in two-sided platforms. In the settings we consider, customers rent listings; rented listings are occupied for some amount of time, then become available. Platforms typically use two common designs to study interventions in such settings: customer-side randomization (CR), and listing-side randomization (LR), along with associated estimators. We develop a stochastic model and associated mean field limit to capture dynamics in such systems, and use our model to investigate how the performance of these estimators is affected by interference effects between listings and between customers. Good experimental design depends on market balance: we show that in highly demand-constrained markets, CR is unbiased, while LR is biased; conversely, in highly supply-constrained markets, LR is unbiased, while CR is biased. We also study a design based on two-sided randomization (TSR) where both customers and listings are randomized to treatment and control, and show that appropriate choices of such designs can be unbiased in both extremes of market balance, and also yield low bias in intermediate regimes of market balance. Full paper available at: https://arxiv.org/abs/2002.05670.
Deep Reinforcement Learning for Intelligent Reflecting Surfaces: Towards Standalone Operation

The promising coverage and spectral efficiency gains of intelligent reflecting surfaces (IRSs) are attracting increasing interest. To adopt these surfaces in practice, however, several challenges need to be addressed. One of these main challenges is how to configure the reflecting coefficients on these passive surfaces without requiring massive channel estimation or beam training overhead. Earlier work suggested leveraging supervised learning tools to predict the IRS reflection matrices. While this approach has the potential of reducing the beam training overhead, it requires collecting large datasets for training the neural network models. In this paper, we propose a novel deep reinforcement learning framework for predicting the IRS reflection matrices with minimal beam training overhead. Simulation results show that the proposed online learning framework can converge to the optimal rate that assumes perfect channel knowledge. This represents an important step towards realizing a standalone IRS operation, where the surface configures itself without any control from the infrastructure.
Adults' difficulties in identifying concealment among children interviewed with the putative confession instructions

The putative confession (PC) instructions (“[suspect] told me everything that happened and wants you to tell the truth”) increases children’s honesty. However, research has shown that children who maintain secrecy despite the PC are more convincing. We examined whether (a) the PC undermines adults’ deception detection abilities or (b) children who conceal despite the PC are better deceivers. Adults evaluated truthful and deceptive children interviewed with the PC where the PC portion of the interview was either present or absent. Adults’ deception detection was no worse when the PC was present; in fact, it was slightly better. Rather than negatively affecting adults’ ability to detect deception, the PC selects an unusually convincing group of concealers.
Measuring Racial/Ethnic Retirement Wealth Inequality

As the US population becomes more diverse, it will be increasingly important for policymakers addressing Social Security’s solvency to understand how reliant various racial and ethnic groups will be on the program versus other sources of retirement wealth. Yet, to date, studies on retirement wealth have tended not to focus on race and ethnicity, have largely ignored the role of Social Security, or have excluded the most recent cohort approaching retirement—the Late Boomers. This project uses data from the Health and Retirement Study (HRS) to document the retirement resources of White, Black, and Hispanic households at various points in the wealth distribution for five HRS cohorts of 51- to 56-year-olds between 1992 and 2016. TOPICS:Retirement, wealth management, social security Key Findings ▪ In 2016, the typical Black household had 46 percent of the retirement wealth of the typical White household; the typical Hispanic household had 49 percent. This inequality would be much higher but for the presence of Social Security. ▪ The 1992 to 2010 HRS cohorts showed little change in retirement wealth inequality, although a decline in 51- to 56-year-old White households’ retirement wealth between 2010 and 2016 narrowed the racial and ethnic gaps in retirement wealth slightly. ▪ The progressivity of Social Security, combined with lower average incomes for minority households, means that replacement rates are more equal than wealth—in 2016, the replacement rate of Black households was 82 percent of White households and Hispanic households was 95 percent.
Kruskal-Based Approximation Algorithm for the Multi-Level Steiner Tree Problem

We study the multi-level Steiner tree problem: a generalization of the Steiner tree problem in graphs where terminals T require varying priority, level, or quality of service. In this problem, we seek to find a minimum cost tree containing edges of varying rates such that any two terminals u, v with priorities P(u), P(v) are connected using edges of rate min{P(u),P(v)} or better. The case where edge costs are proportional to their rate is approximable to within a constant factor of the optimal solution. For the more general case of non-proportional costs, this problem is hard to approximate with ratio c log log n, where n is the number of vertices in the graph. A simple greedy algorithm by Charikar et al., however, provides a min{2(ln |T|+1), 𝓁 ρ}-approximation in this setting, where ρ is an approximation ratio for a heuristic solver for the Steiner tree problem and 𝓁 is the number of priorities or levels (Byrka et al. give a Steiner tree algorithm with ρ≈1.39, for example). In this paper, we describe a natural generalization to the multi-level case of the classical (single-level) Steiner tree approximation algorithm based on Kruskal’s minimum spanning tree algorithm. We prove that this algorithm achieves an approximation ratio at least as good as Charikar et al., and experimentally performs better with respect to the optimum solution. We develop an integer linear programming formulation to compute an exact solution for the multi-level Steiner tree problem with non-proportional edge costs and use it to evaluate the performance of our algorithm on both random graphs and multi-level instances derived from SteinLib.
Ion-specific clustering of metal–amphiphile complexes in rare earth separations

The nanoscale structure of a complex fluid can play a major role in the selective adsorption of ions at the nanometric interfaces, which is crucial in industrial and technological applications. Here we study the effect of anions and lanthanide ions on the nanoscale structure of a complex fluid formed by metal-amphiphile complexes, using small angle X-ray scattering. The nano- and mesoscale structures we observed can be directly connected to the preferential transfer of light (La and Nd) or heavy (Er and Lu) lanthanides into the complex fluid from an aqueous solution. While toluene-based complex fluids containing trioctylmethylammonium-nitrate (TOMA-nitrate) always show the same mesoscale hierarchical structure regardless of lanthanide loading and prefer light lanthanides, those containing TOMA-thiocyanate show an evolution of the mesoscale structure as a function of the lanthanide loading and prefer heavy lanthanides. The hierarchical structure indicates the presence of attractive interactions between ion-amphiphile aggregates, causing them to form clusters. A clustering model that accounts for the hard sphere repulsions and short-range attractions between the aggregates has been adapted to model the X-ray scattering results. The new model successfully describes the nanoscale structure and helps in understanding the mechanisms responsible for amphiphile assisted ion transport between immiscible liquids. Accordingly, our results imply different mechanisms of lanthanide transport depending on the anion present in the complex fluid and correspond with anion-dependent trends in rare earth separations.