cssi/SciSciGPT-SciSciNet huggingface dataset:
Leveraged volume sampling for linear regression

Suppose an n x d design matrix in a linear regression problem is given, but the response for each point is hidden unless explicitly requested. The goal is to sample only a small number k << n of the responses, and then produce a weight vector whose sum of squares loss over *all* points is at most 1+epsilon times the minimum. When k is very small (e.g., k=d), jointly sampling diverse subsets of points is crucial. One such method called "volume sampling" has a unique and desirable property that the weight vector it produces is an unbiased estimate of the optimum. It is therefore natural to ask if this method offers the optimal unbiased estimate in terms of the number of responses k needed to achieve a 1+epsilon loss approximation. Surprisingly we show that volume sampling can have poor behavior when we require a very accurate approximation -- indeed worse than some i.i.d. sampling techniques whose estimates are biased, such as leverage score sampling. We then develop a new rescaled variant of volume sampling that produces an unbiased estimate which avoids this bad behavior and has at least as good a tail bound as leverage score sampling: sample size k=O(d log d + d/epsilon) suffices to guarantee total loss at most 1+epsilon times the minimum with high probability. Thus, we improve on the best previously known sample size for an unbiased estimator, k=O(d^2/epsilon). Our rescaling procedure leads to a new efficient algorithm for volume sampling which is based on a "determinantal rejection sampling" technique with potentially broader applications to determinantal point processes. Other contributions include introducing the combinatorics needed for rescaled volume sampling and developing tail bounds for sums of dependent random matrices which arise in the process.
A Generative-Discriminative Basis Learning Framework to Predict Clinical Severity from Resting State Functional MRI Data

We propose a matrix factorization technique that decomposes the resting state fMRI (rs-fMRI) correlation matrices for a patient population into a sparse set of representative subnetworks, as modeled by rank one outer products. The subnetworks are combined using patient specific non-negative coefficients; these coefficients are also used to model, and subsequently predict the clinical severity of a given patient via a linear regression. Our generative-discriminative framework is able to exploit the structure of rs-fMRI correlation matrices to capture group level effects, while simultaneously accounting for patient variability. We employ ten fold cross validation to demonstrate the predictive power of our model on a cohort of fifty eight patients diagnosed with Autism Spectrum Disorder. Our method outperforms classical semi-supervised frameworks, which perform dimensionality reduction on the correlation features followed by non-linear regression to predict the clinical scores.
Gene Birth Contributes to Structural Disorder Encoded by Overlapping Genes.

The same nucleotide sequence can encode two protein products in different reading frames. Overlapping gene regions encode higher levels of intrinsic structural disorder (ISD) than nonoverlapping genes (39% vs. 25% in our viral dataset). This might be because of the intrinsic properties of the genetic code, because one member per pair was recently born de novo in a process that favors high ISD, or because high ISD relieves increased evolutionary constraint imposed by dual-coding. Here, we quantify the relative contributions of these three alternative hypotheses. We estimate that the recency of de novo gene birth explains 32 % or more of the elevation in ISD in overlapping regions of viral genes. While the two reading frames within a same-strand overlapping gene pair have markedly different ISD tendencies that must be controlled for, their effects cancel out to make no net contribution to ISD. The remaining elevation of ISD in the older members of overlapping gene pairs, presumed due to the need to alleviate evolutionary constraint, was already present prior to the origin of the overlap. Same-strand overlapping gene birth events can occur in two different frames, favoring high ISD either in the ancestral gene or in the novel gene; surprisingly, most de novo gene birth events contained completely within the body of an ancestral gene favor high ISD in the ancestral gene (23 phylogenetically independent events vs. 1). This can be explained by mutation bias favoring the frame with more start codons and fewer stop codons.
Economic Impact Analysis of Control Plane Architectures in Software Defined Networking (SDN)

Economical and operational facets of networks drive the necessity for significant changes towards fundamentals of networking architectures. Recently, the momentum of programmable networking attempts illustrates the significance of economic aspects of network technologies. Software Defined Networking (SDN) has got the attention of researchers from both academia and industry as a means to decrease network costs and generate revenue for service providers due to features it promises in networking. In this article, we perform an economic analysis of SDN about different popular SDN control plane architectures: Centralized Control Plane (CCP), Distributed Control Plane with Local View (DCP_LV), and Hierarchical Control Plane (HCP) model. In particular, we investigate the economic impact of these control plane architectures about the unit cost for a service with bandwidth QoS parameter as well as Total Cost of Ownership (TCO) and network revenue for network owners under different traffic patterns. We characterize the unit cost for a service concerning CAPEX, OPEX, and workload of a network in a certain time period and apply the calculation methods in different SDN control plane models. Our experiments and analysis show that CCP model shows the highest TCO while DCP_LV model results in lowest amount among them. In addition, HCP model shows the lowest unit cost for a service among all models while CCP gives the highest cost for the same service tier. This work aims at being a useful primer to providing insights regarding the economic impact of control plane architectures in SDN for network researchers and owners to plan their investments.
A versatile hybrid agent-based, particle and partial differential equations method to analyze vascular adaptation.

Failure of peripheral endovascular interventions occurs at the intersection of vascular biology, biomechanics, and clinical decision making. It is our hypothesis that most of the endovascular treatments share the same driving mechanisms during post-surgical follow-up, and accordingly, a deep understanding of them is mandatory in order to improve the current surgical outcome. This work presents a versatile model of vascular adaptation post vein graft bypass intervention to treat arterial occlusions. The goal is to improve the computational models developed so far by effectively modeling the cell-cell and cell-membrane interactions that are recognized to be pivotal elements for the re-organization of the graft’s structure. A numerical method is here designed to combine the best features of an Agent-Based Model and a Partial Differential Equations model in order to get as close as possible to the physiological reality while keeping the implementation both simple and general.
Responsibility Centers, Decision Rights, and Synergies

ABSTRACT We consider the optimal allocation of decision rights over noncontractible specific investments. Risk-averse business unit managers each engage in general (stand-alone) operations and inve...
Dynamics of the Gender Gap in High Math Achievement

This paper examines the dynamics of the gender gap in high math achievement over the high school years using data from the American Mathematics Competition. A clear gender gap is already present by 9th grade and the gender gap widens over the high school years. High-achieving students must substantially improve their performance from year to year to maintain their within-cohort rank, but there is nonetheless a great deal of persistence in the rankings. Several gender-related differences in the dynamics contribute to the widening of the gender gap, including differences in dropout rates and in the mean and variance of year-to-year improvements among continuing students. A decomposition indicates that the most important difference is that fewer girls make large enough gains to move up substantially in the rankings. An analysis of students on the margin of qualifying for a prestigious second stage exam provides evidence of a discouragement effect: some react to falling just short by dropping out of participating in future years, and this reaction is more common among girls.
Introduction to RF simulation and its application

Radio-frequency (RF) circuits exhibit several distinguishing characteristics that make them difficult to simulate using traditional SPICE transient analysis. The various extensions to the harmonic balance and shooting method simulation algorithms are able to exploit these characteristics to provide rapid and accurate simulation for these circuits. This paper is an introduction to RF simulation methods and how they are applied to make common RF measurements. It describes the unique characteristics of RF circuits, the methods developed to simulate these circuits, and the application of these methods.
Rapid embryonic cell cycles defer the establishment of heterochromatin by Eggless/SetDB1 in Drosophila.

Acquisition of chromatin modifications during embryogenesis distinguishes different regions of an initially naive genome. In many organisms, repetitive DNA is packaged into constitutive heterochromatin that is marked by di/trimethylation of histone H3K9 and the associated protein HP1a. These modifications enforce the unique epigenetic properties of heterochromatin. However, in the early Drosophila melanogaster embryo, the heterochromatin lacks these modifications, which appear only later, when rapid embryonic cell cycles slow down at the midblastula transition (MBT). Here we focus on the initial steps restoring heterochromatic modifications in the embryo. We describe the JabbaTrap, a technique for inactivating maternally provided proteins in embryos. Using the JabbaTrap, we reveal a major requirement for the methyltransferase Eggless/SetDB1 in the establishment of heterochromatin. In contrast, other methyltransferases contribute minimally. Live imaging reveals that endogenous Eggless gradually accumulates on chromatin in interphase but then dissociates in mitosis, and its accumulation must restart in the next cell cycle. Cell cycle slowing as the embryo approaches the MBT permits increasing accumulation and action of Eggless at its targets. Experimental manipulation of interphase duration shows that cell cycle speed regulates Eggless. We propose that developmental slowing of the cell cycle times embryonic heterochromatin formation.
Combining the Causal Judgments of Experts with Possibly Different Focus Areas.

In many real-world settings, a decision-maker must combine information provided by different experts in order to decide on an effective policy. Alrajeh, Chockler, and Halpern [2018] showed how to combine causal models that are compatible in the sense that, for variables that appear in both models, the experts agree on the causal structure. In this work we show how causal models can be combined in cases where the experts might disagree on the causal structure for variables that appear in both models due to having different focus areas. We provide a new formal definition of compatibility of models in this setting and show how compatible models can be combined. We also consider the complexity of determining whether models are compatible. We believe that the notions defined in this work are of direct relevance to many practical decision making scenarios that come up in natural, social, and medical science settings.
A phylogenomic framework, evolutionary timeline and genomic resources for comparative studies of decapod crustaceans.

Comprising over 15 000 living species, decapods (crabs, shrimp and lobsters) are the most instantly recognizable crustaceans, representing a considerable global food source. Although decapod system...
Capacity Pooling in Hospitals: The Hidden Consequences of Off-Service Placement

Hospital managers struggle with the day-to-day variability in patient admissions to different clinical services, each of which typically has a fixed allocation of hospital beds. In response, many h...
Measured Performance of Building Integrated Photovoltaic Panels—Round 2

Architects, building designers, and building owners presently lack sufficient resources for thoroughly evaluating the economic impact of building integrated photovoltaics (BIPV). The National Institute of Standards and Technology (NIST) is addressing this deficiency by evaluating computer models used to predict the electrical performance of BIPV components. To facilitate this evaluation, NIST is collecting long-term BIPV performance data that can be compared against predicted values. The long-term data, in addition, provides insight into the relative merits of different building integrated applications, helps to identify performance differences between cell technologies, and reveals seasonal variations. This paper adds to the slowly growing database of long-term performance data on BIPV components. Results from monitoring eight different building-integrated panels over a 12-month period are summarized. The panels are installed vertically, face true south, and are an integral part of the building's shell. The eight panels comprise the second set of panels evaluated at the NIST test facility. Cell technologies evaluated as part of this second round of testing include single-crystalline silicon, polycrystalline silicon, and two thin film materials: tandem-junction amorphous silicon (2-a-Si) and copper-indium-diselenide (CIS). Two 2-a-Si panels and two CIS panels were monitored. For each pair of BIPV panels, one was insulated on its back side while the back side of the second panel was open to the indoor conditioned space. The panel with the back side thermal insulation experienced higher midday operating temperatures. The higher operating temperatures caused a greater dip in maximum power voltage. The maximum power current increased slightly for the 2-a-Si panel but remained virtually unchanged for the CIS panel. Three of the remaining four test specimens were custom-made panels having the same polycrystalline solar cells but different glazings. Two different polymer materials were tested along with 6 mm-thick, low-iron float glass. The two panels having the much thinner polymer front covers consistently outperformed the panel having the glass front. When compared on an annual basis, the energy production of each polymer-front panel was 8.5% higher than the glass-front panel. Comparison of panels of the same cell technology and comparisons between panels of different cell technologies are made on daily, monthly, and annual bases. Efficiency based on coverage area, which excludes the panel's inactive border, is used for most between panel comparisons. Annual coverage-area conversion efficiencies for the vertically-installed BIPV panels range from a low of 4.6% for the 2-a-Si panels to a high of 12.2% for the two polycrystalline panels having the polymer front covers. The insulated single crystalline panel only slightly outperformed the insulated CIS panel, 10.1% versus 9.7%.
Mother-friendly companies, work-life balance, and emotional well-being: is there a relationship to financial performance and risk level?

Research in philosophy, sociology, history, and business indicates that the family is the key building block of a nation or culture. In families, parents often struggle with time allocation between their jobs and family life. The pursuit of career and wealth can easily become over-prioritised to the detriment of family. Even in ancient times, this was a problem, as indicated by the wise king Solomon, who warned: "Those who love money will never have enough." In recent decades, the proportion of women in the labour force has greatly increased. Being mother-friendly may be ethically right and socially desirable, but what is the financial impact on companies with human resource policies that facilitate the mother role of female employees? Findings of this study provide support that mother-friendly firms experience better financial performance; specifically, higher market value of equity. This is a notable finding, suggesting that the capital markets value firms with 'mother friendly' attributes. This affirms prior research that shows enhancing work-life balance, which facilitates emotional well-being, is associated with improved job performance, which in turn is associated with better company financial performance.
Iterative Relevance Feedback for Answer Passage Retrieval with Passage-Level Semantic Match

Relevance feedback techniques assume that users provide relevance judgments for the top k (usually 10) documents and then re-rank using a new query model based on those judgments. Even though this is effective, there has been little research recently on this topic because requiring users to provide substantial feedback on a result list is impractical in a typical web search scenario. In new environments such as voice-based search with smart home devices, however, feedback about result quality can potentially be obtained during users’ interactions with the system. Since there are severe limitations on the length and number of results that can be presented in a single interaction in this environment, the focus should move from browsing result lists to iterative retrieval and from retrieving documents to retrieving answers. In this paper, we study iterative relevance feedback techniques with a focus on retrieving answer passages. We first show that iterative feedback is more effective than the top-k approach for answer retrieval. Then we propose an iterative feedback model based on passage-level semantic match and show that it can produce significant improvements compared to both word-based iterative feedback models and those based on term-level semantic similarity.
Patients With Chronic Liver Disease Suggestive of Nonalcoholic Fatty Liver Disease May Be at Higher Risk for Drug-Induced Liver Injury

To date, there have been no studies that systematically examined if individuals with nonalcoholic fatty liver disease (NAFLD) have an increased risk of drug-induced liver injury (DILI). We conducted a study to test if the frequency of suspected DILI from prescription agents is higher in individuals with chronic liver disease (CLD) suggestive of NAFLD.
Joint Alignment of Multiple Protein-Protein Interaction Networks via Convex Optimization.

Motivation: High-throughput experimental techniques have been producing more and more protein-protein interaction (PPI) data. PPI network alignment greatly benefits the understanding of evolutionary relationship among species, helps identify conserved sub-networks and provides extra information for functional annotations. Although a few methods have been developed for multiple PPI network alignment, the alignment quality is still far away from perfect and thus, new network alignment methods are needed. Result: In this paper, we present a novel method, denoted as ConvexAlign, for joint alignment of multiple PPI networks by convex optimization of a scoring function composed of sequence similarity, topological score and interaction conservation score. In contrast to existing methods that generate multiple alignments in a greedy or progressive manner, our convex method optimizes alignments globally and enforces consistency among all pairwise alignments, resulting in much better alignment quality. Tested on both synthetic and real data, our experimental results show that ConvexAlign outperforms several popular methods in producing functionally coherent alignments. ConvexAlign even has a larger advantage over the others in aligning real PPI networks. ConvexAlign also finds a few conserved complexes among 5 species which cannot be detected by the other methods.
Tumor Cavity Recurrence after Stereotactic Radiosurgery of Surgically Resected Brain Metastases: Implication of Deviations from Contouring Guidelines.

BACKGROUND Significant heterogeneity exists in target volumes for postoperative stereotactic radiosurgery (SRS) for brain metastases. A set of contouring guidelines was recently published, and we investigated the impact of deviations. METHODS Patients (n = 41) undergoing single-fraction Gamma Knife SRS following surgical resection of brain metastases from 2011 to 2017 were retrospectively reviewed. SRS included the entire contrast-enhancing cavity with heterogeneity in inclusion of the surgical tract and no routine margin along the dura or clinical target volume margin. Follow-up MR imaging was fused with SRS plans to assess patterns of failure. RESULTS The median follow-up was 11.1 months with a median prescription of 18 Gy. There were 5 local failures: infield (n = 3, 60%), surgical tract (n = 1, 20%), and marginal > 5 mm from the resection cavity (n = 1, 20%). No marginal failures < 5 mm or dural margin failures were noted. For deep lesions (n = 13), 62% (n = 8) had the entire tract covered. The only tract recurrence was in a deep lesion without coverage of the surgical tract (n = 1/5). CONCLUSION In this small preliminary experience, despite no routine inclusion of the dural tract or bone flap, no failures were noted in these locations. Omission of the surgical tract in deep lesions may increase failure rates.
Explain3D: explaining disagreements in disjoint datasets

Data plays an important role in applications, analytic processes, and many aspects of human activity. As data grows in size and complexity, we are met with an imperative need for tools that promote understanding and explanations over data-related operations. Data management research on explanations has focused on the assumption that data resides in a single dataset, under one common schema. But the reality of today's data is that it is frequently unintegrated, coming from different sources with different schemas. When different datasets provide different answers to semantically similar questions, understanding the reasons for the discrepancies is challenging and cannot be handled by the existing single-dataset solutions.In this paper, we propose explain3D, a framework for explaining the disagreements across disjoint datasets (3D). Explain3D focuses on identifying the reasons for the differences in the results of two semantically similar queries operating on two datasets with potentially different schemas. Our framework leverages the queries to perform a semantic mapping across the relevant parts of their provenance; discrepancies in this mapping point to causes of the queries' differences. Exploiting the queries gives explain3D an edge over traditional schema matching and record linkage techniques, which are query-agnostic. Our work makes the following contributions: (1) We formalize the problem of deriving optimal explanations for the differences of the results of semantically similar queries over disjoint datasets. Our optimization problem considers two types of explanations, provenance-based and value-based, defined over an evidence mapping, which makes our solution interpretable. (2) We design a 3-stage framework for solving the optimal explanation problem. (3) We develop a smart-partitioning optimizer that improves the efficiency of the framework by orders of magnitude. (4) We experiment with real-world and synthetic data to demonstrate that explain3D can derive precise explanations efficiently, and is superior to alternative methods based on integration techniques and single-dataset explanation frameworks.
On the asymptotic performance of threshold-based acquisition systems in multipath fading channels

The asymptotic performance of timing acquisition systems having fixed dwell time in multipath fading channels is investigated. The detrimental effect of the multipath channel fading on the acquisition performance is isolated by considering the asymptotic performance as the average signal-to-noise ratio (SNR) increases. It is found that for any threshold such that the average probability of false alarm is less than a given tolerance, the channel fading results in a lower bound on the asymptotic average probability of miss which is nontrivial for a variety of fading scenarios. A threshold-based direct-sequence spread-spectrum signal acquisition system is considered and it is found that the detrimental effect of channel fading on asymptotic acquisition performance, albeit nontrivial, is not very significant. The asymptotic acquisition performance of two threshold-based acquisition schemes for ultra-wideband (UWB) signals with time-hopping (TH) spreading are also evaluated and compared. For both schemes, the detrimental effect of the channel fading on the asymptotic acquisition performance turns out to be significant.
Elbow flexion in neonatal brachial plexus palsy: a meta-analysis of graft versus transfer

Functional elbow flexion recovery is one of the main goals of neonatal brachial plexus palsy (NBPP) reconstruction. The current neurosurgical treatment options include nerve grafting and nerve transfer. The present study sought to examine the literature for comparison of functional elbow flexion recovery in NBPP following nerve grafting or nerve transfer. We conducted a systematic literature review and meta-analysis according to PRISMA guidelines. A search was conducted on Pubmed/Medline and Cochrane for eligible studies published until November of 2018. Odd ratios (OR) and 95% confidence intervals (CI) were calculated to compare functional elbow flexion outcomes between nerve graft and nerve transfer. A random effects model meta-analysis was conducted. A Medical Research Council (MRC) score ≥ 3 or Active Movement Scale (AMS) ≥ 5 was considered a functional recovery of elbow flexion. The present study included 194 patients from 1990 to 2015 across five observational trials. Only pediatric patients with obstetric brachial plexus injury were included. The mean patient age at surgery varied between studies from 5.7 months to 11.9 months and mean follow-up from 12 to 70 months. No complications or cases of donor site morbidity were reported. From the included studies, 118 patients were reported with MRC or AMS scoring usable for odd ratio comparison. Functional recovery occurred with nerve transfer in 95.2% of patients (n = 59/62) and with nerve grafting in 96.4% of patients (n = 54/56). Overall, the outcomes for elbow flexion between the groups appeared similar (OR 1.15, 95% CI 0.19–7.08, I2 2.9%). Comparing nerve grafting and nerve transfer for NBPP, there is no statistically significant difference in functional elbow flexion recovery.
Scalable Fair Clustering

We study the fair variant of the classic $k$-median problem introduced by Chierichetti et al. [2017]. In the standard $k$-median problem, given an input pointset $P$, the goal is to find $k$ centers $C$ and assign each input point to one of the centers in $C$ such that the average distance of points to their cluster center is minimized. In the fair variant of $k$-median, the points are colored, and the goal is to minimize the same average distance objective while ensuring that all clusters have an "approximately equal" number of points of each color. Chierichetti et al. proposed a two-phase algorithm for fair $k$-clustering. In the first step, the pointset is partitioned into subsets called fairlets that satisfy the fairness requirement and approximately preserve the $k$-median objective. In the second step, fairlets are merged into $k$ clusters by one of the existing $k$-median algorithms. The running time of this algorithm is dominated by the first step, which takes super-quadratic time. In this paper, we present a practical approximate fairlet decomposition algorithm that runs in nearly linear time. Our algorithm additionally allows for finer control over the balance of resulting clusters than the original work. We complement our theoretical bounds with empirical evaluation.
Efficient real-time routing for autonomous vehicles through Bayes correlated equilibrium: An information design framework

Abstract In this paper, we propose an information-based approach to eliminate inefficiency in traffic systems in the era of autonomous vehicles. We build up theoretical models to coordinate vehicles through Waze, a pervasive crowdsourcing mapping app. We apply the idea of Bayesian persuasion (Kamenica and Gentzkow, 2011) in the basic model of a single vehicle and implement the unified information design framework (Bergemann and Morris, 2017) in the general model. Since the reliability of the information source (Waze) is crucial, we also incorporate queueing theory into the congestion model to obtain more accurate predictions of the traffic conditions. We demonstrate the significant efficiency improvement of implementing theoretical economic approach in the robotic area.
What do mean impacts miss? Distributional effects of corporate diversification

Abstract Corporate diversification is one of the most debated topics in finance over the past two decades. While it is widely believed that there exists a discount in the stock market valuation of conglomerate firms, the extant research based on least squares methods points to different directions. We argue that the existing empirical analyses ignore some important data features, especially cross sectional heterogeneity, predicted by both theories and casual observations on corporate diversification, and thus cannot provide a complete picture of the diversification discount. Using a quantile regression analysis on U.S. public firms, we investigate the importance of heterogeneity of diversification as well as other firm characteristics. Estimated quantile treatment effects exhibit substantial heterogeneity as predicted. Thus mean impacts miss a great deal. We also tie back differences in the effect of diversification in high-valued and low-valued firms to observable agency characteristics; the most interesting finding is that CEOs seem to play vastly different roles in high-valued and low-valued firms. We conclude that the effect of diversification is likely more varied and more extensive than has been recognized.
Children Exposed to Maternal Obesity or Gestational Diabetes Mellitus During Early Fetal Development Have Hypothalamic Alterations That Predict Future Weight Gain

OBJECTIVE Exposure in utero to maternal obesity or gestational diabetes mellitus (GDM) is linked to a high risk for obesity in offspring. Animal studies suggest that these exposures disrupt the development of the hypothalamus, a brain region that regulates body weight, predisposing offspring to develop obesity. This study tested the hypothesis in humans that in utero exposure to maternal obesity and/or GDM is associated with alterations in the hypothalamic response to glucose, and the altered hypothalamic response would predict greater increases in child adiposity 1 year later. RESEARCH DESIGN AND METHODS Participants were 91 children aged 7–11 years with and without in utero exposure to GDM. Maternal prepregnancy BMI and GDM exposures were determined from electronic medical records. Arterial spin labeling MRI was used to determine the child’s hypothalamic blood flow response to oral glucose. Anthropometric mea-sures were acquired in all children at their initial visit and again 1 year later in a subset of 44 children. RESULTS Children exposed to GDM diagnosed ≤26 weeks gestation had increased hypothalamic blood flow (a marker of hypothalamic activation) in response to glucose when compared with unexposed children, and results remained after adjustments for child age, sex, BMI, and maternal prepregnancy BMI. Maternal prepregnancy BMI was positively associated with the child’s hypothalamic response to glucose. Greater hypothalamic response to glucose predicted greater increases in child’s BMI 1 year later. CONCLUSIONS Increased glucose-linked hypothalamic activation during childhood represents a possible mechanism by which exposure to maternal metabolic disorders during fetal development increases future risk for obesity.
Are populations like a circuit? Comparing isolation by resistance to a new coalescent‐based method

A number of methods commonly used in landscape genetics use an analogy to electrical resistance on a network to describe and fit barriers to movement across the landscape using genetic distance data. These are motivated by a mathematical equivalence between electrical resistance between two nodes of a network and the 'commute time', which is the mean time for a random walk on that network to leave one node, visit the other, and return. However, genetic data are more accurately modelled by a different quantity, the coalescence time. Here, we describe the differences between resistance distance and coalescence time, and explore the consequences for inference. We implemented a Bayesian method to infer effective movement rates and population sizes under both these models, and found that inference using commute times could produce misleading results in the presence of biased gene flow. We then used forwards-time simulation with continuous geography to demonstrate that coalescence-based inference remains more accurate than resistance-based methods on realistic data, but difficulties highlight the need for methods that explicitly model continuous, heterogeneous geography.
Quantitation of perfluoroalkyl acids, parabens and cotinine from single low volume serum sample by validated analytical method

In this paper, we present the results of an analytical method that has been recently developed, validated and successfully applied in a biomonitoring approach. In the environmental pollutant studie...
Should We Tax Sugar-Sweetened Beverages? An Overview of Theory and Evidence

Taxes on sugar-sweetened beverages are growing in popularity and have generated an active public debate. Are they a good idea? If so, how high should they be? Are such taxes regressive? People in the United States and some other countries consume remarkable quantities of sugar-sweetened beverages, and the evidence suggests that this generates significant health costs. Building on recent work, we review the basic economic principles that determine the socially optimal sugar-sweetened beverage tax. The optimal tax depends on (1) externalities, or uninternalized health system costs from diseases caused by sugary drink consumption; (2) internalities, or costs consumers impose on themselves by consuming too many sugary drinks due to poor nutrition knowledge and/or lack of self-control; and (3) regressivity, or how much the financial burden and the internality benefits from the tax fall on the poor. We summarize the empirical evidence about the key parameters that determine how large the tax should be. Our calculations suggest that sugar-sweetened beverage taxes are welfare enhancing and indeed that the optimal sugar-sweetened beverage tax rate may be higher than the 1 cent per ounce rate most commonly used in US cities. We end with seven concrete suggestions for policymakers considering a sugar-sweetened beverage tax.
Synthesis of the C1-C21 Fragment of the Serine/Threonine Phosphatase Inhibitor Tautomycin.

Compound 40 containing the C-1−C-21 region of tautomycin has been synthesized. The two halves (4 and 5) of this spirocyclic section were each constructed using Matteson's chloromethylene insertion reaction. Cr/Ni-mediated coupling of compounds 4 and 5 resulted in a structure containing the C-1−C-21 section of tautomycin. Oxidation of the resultant allylic alcohol to the ketone and removal of the α,β unsaturation yielded compound 39. Treatment with DDQ removed both PMB protecting groups and allowed the spirocyclic ketal to form producing compound 40, ready for further extension to the natural product tautomycin.
Tosylmethylamines as “Nonstabilized” α-Aminocarbanion Synthon Equivalents: Advantages and Limitations

Tosylmethylamines (1) are advantageous synthon equivalents for “nonstabilized” α-aminocarbanions of aromatic amines. Clean reactions and high yields are observed provided one-step procedures are ut...
Large-scale chemical–genetics yields new M. tuberculosis inhibitor classes

New antibiotics are needed to combat rising levels of resistance, with new Mycobacterium tuberculosis (Mtb) drugs having the highest priority. However, conventional whole-cell and biochemical antibiotic screens have failed. Here we develop a strategy termed PROSPECT (primary screening of strains to prioritize expanded chemistry and targets), in which we screen compounds against pools of strains depleted of essential bacterial targets. We engineered strains that target 474 essential Mtb genes and screened pools of 100–150 strains against activity-enriched and unbiased compound libraries, probing more than 8.5 million chemical–genetic interactions. Primary screens identified over tenfold more hits than screening wild-type Mtb alone, with chemical–genetic interactions providing immediate, direct target insights. We identified over 40 compounds that target DNA gyrase, the cell wall, tryptophan, folate biosynthesis and RNA polymerase, as well as inhibitors that target EfpA. Chemical optimization yielded EfpA inhibitors with potent wild-type activity, thus demonstrating the ability of PROSPECT to yield inhibitors against targets that would have eluded conventional drug discovery. A high-throughput chemical–genetic screening approach for the discovery of targets and chemicals to treat Mycobacterium tuberculosis yields tenfold more hit compounds than conventional whole-cell screening methods.
Charge and spin diffusion in mesoscopic metal wires and at ferromagnet/nonmagnet interfaces

Issues related to ``charge-spin coupling'' and the diffusive transport of nonequilibrium spin polarized electrons in nonmagnetic materials and at the interface between ferromagnetic and nonmagnetic materials are discussed theoretically. Equations that govern charge and spin transport in three dimensions are derived and appropriate boundary conditions are discussed. These results are applied to a numerical calculation of spin accumulation and diffusion in a two-dimensional Van der Pauw cross. A detailed model of spin transport at ferromagnetic-nonmagnetic metal interfaces is reviewed, the limiting cases of high and low interface conductance are treated, and the relevance of ``resistance mismatch'' for a variety of experimental systems is analyzed.
Syntheses, Structures, and Properties of Six Novel Alkali Metal Tin Sulfides: K2Sn2S8, α-Rb2Sn2S8, β-Rb2Sn2S8, K2Sn2S5, Cs2Sn2S6, and Cs2SnS14

Six alkali metal tin polysulfides and one monosulfide, K 2 Sn 2 S 8 (I), α-Rb 2 Sn 2 S 8 (II), β-Rb 2 Sn 2 S 8 (III), K 2 Sn 2 S 5 (IV), Cs 2 Sn 2 S 6 (V), and Cs 2 SnS 14 (VI), respectively, were synthesized by a molten salt technique. I and IV were made by heating mixtures of Sn/K 2 S/S (molar ratio 1/2/8) at 275 and 320 o C, respectively, for 4-6 days. II and III were made by heating mixtures of Sn/Rb 2 S/S (molar ratio 1/2/12 for II and 1/1/8 for III) at 330 and 450 o C, respectively, for 4-6 days. V and VI were made by heating mixtures of Sn/C 2 S/S (molar ratio 1/3/8 for V and 1/2/8-12 for VI) at 275°C for 4-6 days
Chemical Reaction Mechanisms of Diamond Growth

It is becoming increasingly apparent that future progress in diamond chemical vapor deposition depends on deeper understanding of the underlying mechanism of surface processes. Substantial efforts toward this goal have led to several conclusions on which consensus is beginning to emerge. Among them are the mediating role of hydrogen atoms, generic features of the growth kinetics, thermodynamic stability of reconstructed (100) surfaces, and the insertion reaction of methyl into (100)-(2×l) dimers. Despite these efforts, an overall picture of diamond growth in terms of elementary processes is still lacking. In this paper, the current state of mechanistic understanding is reviewed, emphasizing common themes, and new results are presented. Among the latter are the effect of reaction reversibility on surface morphology, surface migration, and a new mechanism for diamond growth from acetylene.
Synthesis of C-aryl and C-alkyl glycosides using glycosyl phosphates.

Mannosyl and glucosyl phosphate donors were successfully used in constructing C-aryl linkages common to many natural products via a Lewis acid induced Fries-like rearrangement. The rearrangement was stereo- and regiospecific, yielding only one C-glycoside product. C-Alkyl glycoside carbohydrate mimetics were generated by using silicon-derived C-nucleophiles and glycosyl phosphates.
Non-thermal behavior in conformal boundary states

Cardy has recently observed that certain carefully tuned states of 1+1 CFTs on a timelike strip are periodic with period set by the light-crossing time. The states in question are dened by Euclidean time evolution of conformal boundary states associated with the particular boundary conditions imposed on the edges of the strip. We explain this behavior, and the associated lack of thermalization, by showing that such states are Lorentz-signature conformal transformations of the strip ground state. Taking the long- strip limit implies that states used to model thermalization on the Minkowski plane admit non-thermal conformal extensions beyond future innity of the Minkowski plane, and thus retain some notion of non-thermal behavior at late times. We also comment on the holo- graphic description of these states.
Federalism, Partial Prohibition, and Cross-Border Sales: Evidence from Recreational Marijuana

Abstract Marijuana is partially prohibited: though banned federally, it is available to 1 in 4 U.S. adults under state statutes. We measure the size of the interstate trade generated by state-level differences in legal status with a natural experiment: Oregon allowed stores to sell marijuana for recreational use on October 1, 2015, next to Washington where stores had been selling recreational marijuana since July 2014. Using administrative data covering the universe of Washington's sales and a differences-in-discontinuities approach, we find retailers along the Oregon border experienced a 36% decline in sales immediately after Oregon's market opened. We investigate the home location of recent online reviewers of marijuana retailers and find similar cross-border patterns. By the end of Washington's 2018 fiscal year, our results imply that Washington had earned between $44 million and $75 million in tax revenue from cross-border shoppers. These cross-border incentives may create a “race to legalize.”
All-electrochemical synthesis of submicrometer Cu structures on electrochemically machined p-Si substrates

A maskless all-electrochemical method for the deposition of micro- and nanoscale Cu structures on p-Si is reported. The first step involves the electrochemical machining of p-type Si in HF by applying nanosecond voltage pulses between a tool and a Si electrode. This process generates a localized defect structure, which is successively utilized to achieve selective metal electrodeposition. The resolution of the process is limited mainly by the tool dimensions and by the time constants involved in electrochemical machining, which lead to a limited spread of the defect region on the Si surface. Copper isolated islands with 500 nm diameter have been grown by electrodeposition, with high selectivity. This process has the potential to become a preferred technique for the placement and growth of submicrometer metal islands on semiconductor surfaces.
The stereospecific preparation of (E)-1-aryl-F-1,3-butadienes

Abstract The Pd (PPh 3 ) 4 /Cu(I)I catalyzed cross coupling of ( Z )-1-tri- n -butylstannyl-1,2,3,4,4-pentafluoro-1,3-butadiene with substituted aryl iodides provides a useful stereospecific route to ( E )-1-aryl-1,2,3,4,4-pentafluoro-1,3-butadienes. Substituents, such as 4-nitro, 2-nitro, H, 3-CF 3 , 3-OCH 3 , 2-CH 3 , 1- i Pr react stereospecifically with the dienyl stannane synthon. Only with a bulky electron-withdrawing substuent, such as 2-CF 3 , did significant isomerization occur in isolation of the aryl diene. The bis-coupled product is formed stereospecifically with 1,4-diiodobenzene. The methodology could be extended to stereospecifically prepared the 1-triethylsilyl-1 E ,3 E ,-1,2,3,4,5,6,6-heptafluoro-1,3,5-hexatriene synthon.
Highly Stable Catalysts for the Stereospecific Polymerization of Styrene

The synthesis of eight new catalyst precursors is described, and their catalysis of syndiospecific styrene polymerization when activated by methylaluminoxane (MAO) is compared with IndTiCl3. Phenyl substitution increases polymerization activity (A) in the order 1,3-Ph2Ind < 2-PhInd < 1-PhInd; the opposite trend was observed for the yield (SY) of syndiotactic polystyrene (s-PS). The optimum polymerization temperature (Tp) is 50 °C; an increase of Tp decreases A, SY, and molecular weight (MW) of s-PS. Benz[e]IndTiCl3 (6a) as well as the 2-methyl (6b) and 1,2,3-trimethyl (11) derivatives have been synthesized. Complexes 6a/MAO and 6b/MAO have exceedingly high values of A ≈ 1.8 × 108 g of PS/(mol of Ti·mol of styrene·h) for a turnover rate of 450 s-1, SY over 92%, and MW ≈ 5 × 105. These parameters were only slightly lowered at Tp = 100 °C, indicating very thermally stable, catalytically active species. These catalyst precursors are stable in solution toward air and moisture up to 48 h and are indefinitely st...
One-Pot Synthesis of 2-Deoxy-β-oligosaccharides

A new one-pot method using glycosyl phosphites for the synthesis of 2-deoxy-β-oligosaccharides is described.
Simple synthesis of endo-2-bromo-5-thiabicyclo[2.1.1]hexane†

A brief synthesis of endo-2-bromo-5-thiabicyclo [2.1.1]hexane (9) has been developed involving conversion of 3-cyclopentenol (6) to 3-thioacetoxycyclopentene (7), bromination of this giving trans-1,2-dibromo-4-thioacetoxycyclopentane (8), and treatment of the latter with base. Compound 9 is oxidized to its S-oxide 10 and S, S-dioxide 11. Comparative 13C and 1H NMR data are given for 9–11.
Second generation instruments for the Laser Interferometer Gravitational Wave Observatory (LIGO)

The interferometers being planned for second generation LIGO promise an order of magnitude increase in broadband strain sensitivity-with the corresponding cubic increase in detection volume-and an extension of the observation band to lower frequencies. In addition, one of the interferometers may be designed for narrowband performance, giving further improved sensitivity over roughly an octave band above a few hundred Hertz. This article discusses the physics and technology of these new interferometer designs, and presents their projected sensitivity spectra.
DIRECTIONAL SUPERPARAMAGNETISM AND PHOTOLUMINESCENCE IN CLUSTERS OF MAGNETITE AND CADMIUM SELENIDE NANOPARTICLES

ZnO microcrystals, Ca2Nb3O10 nanoplates, and LiMo3Se3 nanowires were used to chemically assemble CdSe and magnetite nanoparticles into discrete nanostructures. The CdSe-containing clusters exhibit ...
Preparation of low-dimensional cluster materials: Synthesis, structure, and properties of A2Ti2Nb6Cl14O5 (A = K, Rb, Cs), a series of one-dimensional titanium niobium oxychlorides

In the course of our systematic investigation of metal oxychloride systems aimed at the preparation of low-dimensional compounds, a new series of niobium oxychloride cluster compounds, A2Ti2Nb6Cl14O5 (A = K, Rb, Cs), was obtained from stoichiometric amounts of ACl (A = K, Rb, Cs), Ti, Nb2O5, NbCl5, and Nb, heated at 750 °C. The crystal structures of the series were determined by single-crystal X-ray diffraction techniques. The compounds crystallize in the monoclinic system, space group C2/c, with unit cell parameters a = 21.503(3) A, b = 8.816(1) A, c = 15.710(2) A, β = 116.21(1)°, V = 2672.1(6) A3, and Z = 4 for A = Rb. The full-matrix least-squares refinement against F 2 converged to R1 = 0.043 (Fo > 4σ(Fo)) and wR2 = 0.089 (all data for A = Rb). The crystal structure of A2Ti2Nb6Cl14O5 has one-dimensional character. It is based on chains formed by (Nb6 ) octahedral niobium clusters connected to each other through apical chloride ligands and titanium counterions. The chains are held together by alkali ...