cssi/SciSciGPT-SciSciNet huggingface dataset:
Extending JML for modular specification and verification of multi-threaded programs

The Java Modeling Language (JML) is a formal specification language for Java that allows developers to specify rich software contracts for interfaces and classes, using pre- and postconditions and invariants. Although JML has been widely studied and has robust tool support based on a variety of automated verification technologies, it shares a problem with many similar object-oriented specification languages—it currently only deals with sequential programs. In this paper, we extend JML to allow for effective specification of multi-threaded Java programs. The new constructs rely on the non-interference notion of method atomicity, and allow developers to specify locking and other non-interference properties of methods. Atomicity enables effective specification of method pre- and postconditions and supports Hoare-style modular reasoning about methods. Thus the new constructs mesh well with JML's existing features. We validate the specification language design by specifying the behavior of a number of complex Java classes designed for use in multi-threaded programs. We also demonstrate that it is amenable to automated verification using model checking technology.
Optimal Timing of Control-Law Updates for Unstable Systems with Continuous Control

The optimal control of a linear system is studied relative to a periodic unstable trajectory using continuous control. Gaussian state uncertainties induce a statistical cost of controlling the state over a long period of time. The length of time between control-law updates directly impacts this cost, and in a hyperbolically unstable system, the time between control updates can take an optimal value. If the amount of uncertainty is fixed, there is an optimal distribution between position and velocity uncertainty. We apply these ideas to study the statistical cost of controlling a spacecraft in the vicinity of a relative equilibrium point and a Halo orbit in the Hill three-body problem.
In traffic flow, cellular automata = kinematic waves

This paper proves that the vehicle trajectories predicted by (i) a simple linear car-following model, CF(L), (ii) the kinematic wave model with a triangular fundamental diagram, KW(T), and (iii) two cellular automata models CA(L) and CA(M) match everywhere to within a tolerance comparable with a single “jam spacing”. Thus, CF(L) = KW(T) = CA(L, M).
Controllability/observability analysis of digital circuits

The testability of a digital circuit is directly related to the difficulty of controlling and observing the logical values of internal nodes from circuit inputs and outputs, respectively. This paper presents a method for analyzing digital circuits in terms of six functions which characterize combinational and sequential controllability and observability.
On convergence analysis of fractionally spaced adaptive blind equalizers

In this paper, we study the convergence analysis of fractionally spaced adaptive blind equalizers. We show that based on the trivial and nontrivial nullspaces of a channel convolution matrix, all equilibria can be classified as channel dependent equilibria (CDE) or algorithm dependent equilibria (ADE). Because oversampling provides channel diversity, the nullspace of the channel convolution matrix is affected. We show that fractionally spaced equalizers (FSEs) do not possess any CDE if a length-zero condition is satisfied. The convergence behavior of these FSE are clearly determined by the specific choice of cost function alone. We characterize the global convergence ability of several popular algorithms simply based on their ADE. We also present an FSE implementation of the super-exponential algorithm. We show that the FSE implementation does not introduce any nonideal approximation. Simulation results are also presented to illustrate the robustness and the improved performance of FSE under the super-exponential algorithm.
Are You Being Served? Political Accountability and Quality of Government

This paper explores, both formally and empirically, the political accountability mechanisms that lie behind the varying levels of public corruption and of effective governance taking place across nations. The first section develops a principal-agent model in which good governance is a function of the extent to which citizens can hold political officials accountable for their actions. Although policy-makers may have strong incentives to appropriate parts of the citizens' income, well-designed institutions (those increasing both informational flows and elite competitiveness) boost political accountability and reduce the space left for the appropriation of rents. The following sections of the paper test the model. The presence of democratic mechanisms of control and an increasingly informed electorate, measured through the frequency of newspaper readership, explain considerably well the distribution of corrupt practices and governmental ineffectiveness in three types of data sets: a large cross-section of countries in the late 1990s for which an extensive battery of governance indicators has been recently developed by Kaufmann et al. (1999a); a panel data set for the period 1980-95 and about 100 nations on corruption and bureaucratic quality based on experts' rankings; and corruption data for the cross-section of US states in the period 1977-95.
Adaptive control of a manipulator with a flexible link

An adaptive controller for a manipulator with one rigid link and one flexible link is presented. The performance and robustness of the controller are demonstrated by numerical simulation results. In the simulations, the manipulator moves in a gravitational field and a finite element model represents the flexible link.
Maximal models of assertion graph in GSTE

Generalized symbolic trajectory evaluation (GSTE) is an extension of symbolic trajectory evaluation (STE). In GSTE, assertion graphs are used to specify properties in a special form of regular automata with antecedent and consequent pairs. This paper presents a new model characterization, called maximal models, for an assertion graph with important properties. Besides their own theoretical significance, maximal models are used to show the implication of two assertion graphs in GSTE. We show that, contrary to the general belief, an assertion graph may have more than one maximal model. We present a provable algorithm to find all maximal models of a linear assertion graph. We devise an algorithm for finding a maximal model for an arbitrary assertion graph.
Interactive property valuations

This paper estimates models of social interactions within residential neighborhoods using data on neighborhood clusters for standard metropolitan areas in the United States from the American Housing Survey for 1985 and 1989. It examines eects of social interactions in the form of reaction functions for homeowners’ valuation of their properties at the level of the immediate residential neighborhood, with neighborhoods consisting of a randomly chosen dwelling unit and about ten nearest neighbors. The paper identifies the eect of endogenous social interactions to be significant and large, ranging from 0.587 to 0.770, and much more important then the dynamic (autoregressive) structure of the model when both variables are present and both are significant. The interactive regressions that it reports improve upon commonly used hedonic regressions as well. The paper provides empirical support for the notion, common in the real estate world, of the importance of neighboring properties in property valuations.
The rate of convergence of AdaBoost

The AdaBoost algorithm was designed to combine many "weak" hypotheses that perform slightly better than random guessing into a "strong" hypothesis that has very low error. We study the rate at which AdaBoost iteratively converges to the minimum of the "exponential loss." Unlike previous work, our proofs do not require a weak-learning assumption, nor do they require that minimizers of the exponential loss are finite. Our first result shows that the exponential loss of AdaBoost's computed parameter vector will be at most e more than that of any parameter vector of l1-norm bounded by B in a number of rounds that is at most a polynomial in B and 1/e. We also provide lower bounds showing that a polynomial dependence is necessary. Our second result is that within C/e iterations, AdaBoost achieves a value of the exponential loss that is at most e more than the best possible value, where C depends on the data set. We show that this dependence of the rate on e is optimal up to constant factors, that is, at least Ω(1/e) rounds are necessary to achieve within e of the optimal exponential loss.
Development of a practical synthesis of novel, pyrrole-based HMG-CoA reductase inhibitors

This paper describes the development of an efficient and scalable second generation synthesis of novel, pyrrole-based HMG-CoA reductase inhibitors. Compound 1 was identified as part of a discovery program aimed at finding improved treatments for hypercholesterolemia. Herein, we describe an efficient synthesis of its highly functionalized pyrrole core followed by attachment of the 3,5-dihydroxyhexanoic acid side chain via ylide olefination chemistry.
Constraint Satisfaction over a Non-Boolean Domain: Approximation Algorithms and Unique-Games Hardness

We study the approximability of the MAX k-CSP problem over non-boolean domains, more specifically over {0,1,...,qi¾? 1} for some integer q. We extend the techniques of Samorodnitsky and Trevisan [19] to obtain a UGC hardness result when qis a prime. More precisely, assuming the Unique Games Conjecture, we show that it is NP-hard to approximate the problem to a ratio greater than q2k/qk. Independent of this work, Austrin and Mossel [2] obtain a more general UGC hardness result using entirely different techniques. We also obtain an approximation algorithm that achieves a ratio of C(q) ·k/qkfor some constant C(q) depending only on q, via a subroutine for approximating the value of a semidefinite quadratic form when the variables take values on the corners of the q-dimensional simplex. This generalizes an algorithm of Nesterov [16] for the ±1-valued variables. It has been pointed out to us [15] that a similar approximation ratio can be obtained by reducing the non-boolean case to a boolean CSP.
Estimating the Payoff to Attending a More Selective College: An Application of Selection on Observables and Unobservables

There are many estimates of the effect of college quality on students' subsequent earnings. One difficulty interpreting past estimates, however, is that elite colleges admit students, in part, based on characteristics that are related to their earnings capacity. Since some of these characteristics are unobserved by researchers who later estimate wage equations, it is difficult to parse out the effect of attending a selective college from the students' pre-college characteristics. This paper uses information on the set of colleges at which students were accepted and rejected to remove the effect of unobserved characteristics that influence college admission. Specifically, we match students in the newly colleted College and Beyond (C&B) Data Set who were admitted to and rejected from a similar set of institutions, and estimate fixed effects models. As another approach to adjust for selection bias, we control for the average SAT score of the schools to which students applied using both the C&B and National Longitudinal Survey of the High School Class of 1972. We find that students who attended more selective colleges do not earn more than other students who were accepted and rejected by comparable schools but attended less selective colleges. However, the average tuition charged by the school is significantly related to the students' subsequent earnings. Indeed, we find a substantial internal rate of return from attending a more costly college. Lastly, the payoff to attending an elite college appears to be greater for students from more disadvantaged family backgrounds.
rSW-seq: Algorithm for detection of copy number alterations in deep sequencing data

Recent advances in sequencing technologies have enabled generation of large-scale genome sequencing data. These data can be used to characterize a variety of genomic features, including the DNA copy number profile of a cancer genome. A robust and reliable method for screening chromosomal alterations would allow a detailed characterization of the cancer genome with unprecedented accuracy. We develop a method for identification of copy number alterations in a tumor genome compared to its matched control, based on application of Smith-Waterman algorithm to single-end sequencing data. In a performance test with simulated data, our algorithm shows >90% sensitivity and >90% precision in detecting a single copy number change that contains approximately 500 reads for the normal sample. With 100-bp reads, this corresponds to a ~50 kb region for 1X genome coverage of the human genome. We further refine the algorithm to develop rSW-seq, (recursive Smith-Waterman-seq) to identify alterations in a complex configuration, which are commonly observed in the human cancer genome. To validate our approach, we compare our algorithm with an existing algorithm using simulated and publicly available datasets. We also compare the sequencing-based profiles to microarray-based results. We propose rSW-seq as an efficient method for detecting copy number changes in the tumor genome.
Exceptional geometry and Borcherds superalgebras

We study generalized diffeomorphisms in exceptional geometry with U-duality group E n(n) from an algebraic point of view. By extending the Lie algebra $$ {\mathfrak{e}}_n $$ to an infinite-dimensional Borcherds superalgebra, involving also the extension to $$ {\mathfrak{e}}_{n+1} $$ , the generalized Lie derivatives can be expressed in a simple way, and the expressions take the same form for any n ≤ 7. The closure of the transformations then follows from the Jacobi identity and the grading of $$ {\mathfrak{e}}_{n+1} $$ with respect to $$ {\mathfrak{e}}_n $$ .
Basic features of coherent radiation generated by relativistic charge bunches

Abstract Radiation generated by relativistic charges can be analyzed and described in exquisite detail. One reason that such detailed analysis is possible is because the phases of radiated photons often are determined completely by the initial conditions of the relativistic charges and the radiating system. The phase relationships between the initial charges and the radiated photons represent coherence in the emitted radiation. A previous paper decribed how this coherence could affect the spatial and spectral distributions of radiation generated by a single charge in a periodic radiator. The present paper discusses a complementary issue; namely, how the temporal shape of a relativistic charge bunch can emphasize specific features of the radiation generated at a single interaction site.
Defining Sustainability In The Business Setting

Sustainability has become a buzzword in organizational research and ecological science. Much has been said about the role of sustainability for organizational development and markets. Thousands of organizations worldwide have adopted sustainability strategies to boost their productivity and develop a competitive advantage. Yet the concept of sustainability is so complex that it is virtually impossible to ensure a standardized definition or for one organization to understand all its facets in detail. Moreover, under the influence of its own popularity, the concept of sustainability constantly evolves and changes meaning. More often than not, organizations and leaders develop a narrow view of sustainability. They consider only the aspects of sustainability that are directly related to their sphere of performance. In this article, three elements of the definition of sustainability are discussed: longevity, maintenance of core principles or purposes, and responsibility to external needs. The term organization is used because the principles are often applicable to governmental and non-profit organizations as well as businesses.
Reporting Discretion and Private Information Communication through Earnings

We model a two-period pure exchange economy where a risk averse manager, who has private information regarding future earnings, is required to issue an earnings report to investors at the end of each period. While the manager is prohibited from directly disclosing her private information, she is allowed to bias reported earnings in the first period, subject to GAAP rules that require that a specified proportion of the bias be reversed subsequently. We show there is a minimum threshold of reversal, such that, when the proportion of required reversal is above this threshold, the manager smooths income and communicates her private information through reported earnings. Consequently, the market attaches greater weight to reported earnings than under a regime that allows no discretion. When the required reversal is below the minimum threshold, the manager increases reported earnings without limit and the equilibrium degenerates. When the manager is not endowed with any private information, the market unravels the “true” earnings and price is unaffected by earnings management. Our results underscore the importance of both allowing and restricting reporting discretion through formal mechanisms.
Climate, Affluence, and Trust Revisiting Climatoeconomic Models of Generalized Trust With Cross-National Longitudinal Data, 1981-2009

Recent theory predicts that climatic demands in conjunction with wealth-based resources serve to enhance socio-psychological functioning and facilitate the development of cognitive processes such as generalized trust. Past research, however, has provided only cross-sectional evidence to support this theory. In this study, I analyzed a repeated cross-sectional data set that included representative data from 123 societies spread over a 29-year time period. Unbalanced random-effects models and ordinary least squares regression showed that thermal climate and wealth-based resources interacted in their influence on generalized trust. Although the observed associations were robust to potential sources of bias, conditional marginal effect sizes for thermal climate were significantly reduced with the inclusion of confounding control variables. The findings support climatic demands–resource theory of generalized trust, invite new research directions, and yield important implications for trust research and theory.
A DYNAMIC MODEL OF THE U.S. ALLIGATOR INDUSTRY: LESSONS FOR SUSTAINABLE USE AND FARM MANAGEMENT

The American alligator has made a remarkable comeback from the brink of extinction. Commercial alligator production is emerging as an important industry in the South. The industry shows similarities to other livestock industries. This paper draws comparisons with other livestock industries to motivate a structural model of the alligator industry.
From convex optimization to randomized mechanisms: toward optimal combinatorial auctions

We design an expected polynomial time, truthful in expectation, (1-1/e)-approximation mechanism for welfare maximization in a fundamental class of combinatorial auctions. Our results apply to bidders with valuations that are matroid rank sums (MRS), which encompass most concrete examples of submodular functions studied in this context, including coverage functions and matroid weighted-rank functions. Our approximation factor is the best possible, even for known and explicitly given coverage valuations, assuming P ≠ NP. Ours is the first truthful-in-expectation and polynomial-time mechanism to achieve a constant-factor approximation for an NP-hard welfare maximization problem in combinatorial auctions with heterogeneous goods and restricted valuations.Our mechanism is an instantiation of a new framework for designing approximation mechanisms based on randomized rounding algorithms. A typical such algorithm first optimizes over a fractional relaxation of the original problem, and then randomly rounds the fractional solution to an integral one. With rare exceptions, such algorithms cannot be converted into truthful mechanisms. The high-level idea of our mechanism design framework is to optimize directly over the (random) output of the rounding algorithm, rather than over the input to the rounding algorithm. This approach leads to truthful-in-expectation mechanisms, and these mechanisms can be implemented efficiently when the corresponding objective function is concave. For bidders with MRS valuations, we give a novel randomized rounding algorithm that leads to both a concave objective function and a (1-1/e)-approximation of the optimal welfare.
A priori estimates for fluid interface problems

We consider the regularity of an interface between two incompressible and inviscid fluid flows in the presence of surface tension. We obtain local-in-time estimates on the interface in H(3/2)k + 1 and the velocity fields in H(3/2)k. These estimates are obtained using geometric considerations which show that the Kelvin-Helmholtz instabilities are a consequence of a curvature calculation. © 2007 Wiley Periodicals, Inc.
A Miniature Two-Axis Fluxgate Magnetometer

A two-axis miniature fluxgate magnetometer for sounding rocket applications is described. The distinctive feature is that this instrument simultaneously measures, with a single sensing element, two orthogonal components of an external magnetic field. Observed performance is accurately predicted by means of a quantitative linear mathematical model. The dependence of the output voltage on several design parameters is obtained by a Fourier analysis of the output waveform. Computer-aided analyses are presented for core materials of 4-79 Mo-Permalloy and 50-50 Ni-Fe.
Oxidation of Silicon Carbide in Environments Containing Potassium Salt Vapor

At high temperatures in clean oxidizing environments, SiC forms a very protective SiO{sub 2} film, but, in environments containing low levels of gaseous alkali salt contaminants or where condensed salts may deposit on the surface, the resistance of the film is significantly reduced. Oxidation kinetics of SiC were measured by continuous thermogravimetric analysis in a controlled environment containing CO{sub 2}, H{sub 2}O, and O{sub 2} plus low levels of potassium-containing salts. Potassium was found to be incorporated into the SiO{sub 2} scale and to significantly change its transport properties and its morphology. The rate of scale formation was found to increase directly in proportion to K in the scale. A change in mechanism was observed when water vapor was added to the reacting gas stream.
State Regulatory Spending: Boon or Brake for New Enterprise Creation and Income?:

This article addresses a public policy question: Does state government regulation foster or deter economic development? The authors estimate a system of simultaneous equations for income growth, regulation growth, and growth in the number of new enterprises. It is found that regulation does not provide efficient solutions to conflicts and, therefore, does not foster economic development. It is also found that new enterprise formation does not necessarily indicate income growth and economic development.
Identifying plausible adverse drug reactions using knowledge extracted from the literature

Display Omitted We evaluate PSI-based identification of relationships between drugs and ADRs.PSI can incorporate relations and concepts and infer reasoning pathways.PSI is more predictive than a co-occurrence based model.Reasoning pathways suggest supporting evidence from literature for review. Pharmacovigilance involves continually monitoring drug safety after drugs are put to market. To aid this process; algorithms for the identification of strongly correlated drug/adverse drug reaction (ADR) pairs from data sources such as adverse event reporting systems or Electronic Health Records have been developed. These methods are generally statistical in nature, and do not draw upon the large volumes of knowledge embedded in the biomedical literature. In this paper, we investigate the ability of scalable Literature Based Discovery (LBD) methods to identify side effects of pharmaceutical agents. The advantage of LBD methods is that they can provide evidence from the literature to support the plausibility of a drug/ADR association, thereby assisting human review to validate the signal, which is an essential component of pharmacovigilance. To do so, we draw upon vast repositories of knowledge that has been extracted from the biomedical literature by two Natural Language Processing tools, MetaMap and SemRep. We evaluate two LBD methods that scale comfortably to the volume of knowledge available in these repositories. Specifically, we evaluate Reflective Random Indexing (RRI), a model based on concept-level co-occurrence, and Predication-based Semantic Indexing (PSI), a model that encodes the nature of the relationship between concepts to support reasoning analogically about drug-effect relationships. An evaluation set was constructed from the Side Effect Resource 2 (SIDER2), which contains known drug/ADR relations, and models were evaluated for their ability to "rediscover" these relations. In this paper, we demonstrate that both RRI and PSI can recover known drug-adverse event associations. However, PSI performed better overall, and has the additional advantage of being able to recover the literature underlying the reasoning pathways it used to make its predictions.
A New Reactivity Mode for the Diazo Group: Diastereoselective 1,3‐Aminoalkylation Reaction of β‐Amino‐α‐Diazoesters To Give Triazolines

A novel mode of reactivity for the diazo group, the 1,3-addition of a nucleophile and an electrophile to the diazo group, has been realized in the intramolecular aminoalkylation of β-amino-α-diazoesters to form tetrasubstituted 1,2,3-triazolines. The reaction exhibited a broad scope, good functional group tolerance, and excellent diastereoselectivity. In addition, a new Au-catalyzed intramolecular transannulation reaction of the obtained propargyl triazolines to give pyrroles has been discovered.
Opportunistic network coding for video streaming over wireless

In this paper, we study video streaming over wireless networks with network coding capabilities. We build upon recent work, which demonstrated that network coding can increase throughput over a broadcast medium, by mixing packets from different flows into a single packet, thus increasing the information content per transmission. Our key insight is that, when the transmitted flows are video streams, network codes should be selected so as to maximize not only the network throughput but also the video quality. We propose video-aware opportunistic network coding schemes that take into account both aspects, namely (i) the decodability of network codes by several receivers and (ii) the distortion values and playout deadlines of video packets. Simulation results show that our schemes significantly improve both video quality and throughput.
Nonlinear Vortex Interactions on Wing-Canard Configurations

Abstract : Close-coupled wing-canard configurations are ideally suited to applications in which high aircraft maneuverability is required at moderate speeds. The SAAB Viggen has exploited the advantages of placing canard and wing close together, but no theory has been capable of predicting the aerodynamics of this aircraft. In this investigation Sacks' method of simulating vortex sheets with distributions of discrete vortices has been applied to the study of the interaction of a slender wing with a nearly canard surface. The canard is detrimental to both lift and static longitudinal stability. The extent of canard wake roll-up is important in the interaction, and the flatter the wake the more adverse is the interaction. Downward canard deflection may lead to increases in lift of the entire configuration, and it is observed that for small vertical separations between the surfaces the forward portion of the wing is ineffective in producing lift. It is demonstrated that the canard can directly affect the pressure distribution on the wing and application of this configuration to direct lift control and control configured aircraft are noted. (Author)
A Simple DNA Gate Motif for Synthesizing Large-Scale Circuits

The prospects of programming molecular systems to perform complex autonomous tasks has motivated research into the design of synthetic biochemical circuits. Of particular interest to us are cell-free nucleic acid systems that exploit non-covalent hybridization and strand displacement reactions to create cascades that implement digital and analog circuits. To date, circuits involving at most tens of gates have been demonstrated experimentally. Here, we propose a DNA catalytic gate architecture that appears suitable for practical synthesis of large-scale circuits involving possibly thousands of gates.
5-Azidoepibatidine: an exceptionally potent photoaffinity ligand for neuronal α4β2 and α7 nicotinic acetylcholine receptors

Racemic 5-azidoepibatidine [(+/-)-1] was synthesized via 5-aminoepibatidine as a candidate photoaffinity ligand with exceptionally high affinity at the mammalian neuronal nicotinic receptors (K(i) values of 0.027 nM for alpha 4 beta 2 and 9.7 nM for alpha 7) and excellent photoreactivity.
Second Generation Fluorous DEAD Reagents Have Expanded Scope in the Mitsunobu Reaction and Retain Convenient Separation Features

First generation fluorous DEAD reagent bis(perfluorohexylethyl)azo dicarboxylate (C6F13(CH2)2O2CNNCO2(CH2)2C6F13, F-DEAD-1) has been shown to underperform relative to diisopropylazodicarboxylate in difficult Mitsunobu reactions involving hindered alcohols or less acidic pronucleophiles (phenols). Two new second generation fluorous reagents bearing propylene spacers instead of the ethylene spacers show expanded reaction scope while retaining the easy fluorous separation features. Byproducts from “half fluorous” reagent perfluorooctylpropyl tert-butyl azo dicarboxylate (C8F17(CH2)3O2CNNCO2tBu, F-DEAD-2) can be removed by fluorous flash chromatography, and byproducts from bis(perfluorohexylpropyl)azo dicarboxylate (C6F13(CH2)3O2CNNCO2(CH2)3C6F13, F-DEAD-3) can be removed by fluorous solid-phase extraction. The new reagents promise to provide general and complementary solutions for separation problems in Mitsunobu reactions without restricting reaction scope.
Allosteric potentiators of the metabotropic glutamate receptor 2 (mGlu2). Part 1: Identification and synthesis of phenyl-tetrazolyl acetophenones

Abstract We have identified and synthesized a series of aryl-tetrazoyl acetophenones as positive allosteric potentiators of the metabotropic glutamate receptor 2. Structure activity relationship studies directed toward improving the potency and level of potentiation led to the discovery of 22 (EC50 = 93 nM, 128% potentiation).
Racial Differences in the Transactional Relationship Between Depression and Alcohol Use From Elementary School to Middle School.

OBJECTIVE: The aim of this investigation was to test hypothesized reverse prospective relationships between alcohol consumption and depressive symptomatology as a function of race among youth. METHOD: In a two-wave prospective study, 328 European American, 328 African American, and 144 Hispanic American youth were studied at the end of fifth grade (last year of elementary school) and the end of sixth grade (first year of middle school). RESULTS: A positive correlation was observed between alcohol consumption and depressive symptoms among all youth. However, the predictive relationship differed based on race. For European American and Hispanic American youth, depressive symptom levels at the end of elementary school predicted alcohol consumption at the end of the first year of middle school, but the converse relationship was not observed. For African American youth, the opposite pattern was found. Alcohol consumption at the end of elementary school predicted depressive symptom levels at the end of the first year of middle school, and the converse relationship was not observed. CONCLUSIONS: These findings suggest the possibility that etiological relationships between depression and alcohol use vary by race, thus highlighting the importance of considering race when studying the risk process. Language: en
The Early Treatment of Close-range Shotgun Wounds to the Extremities

Some of the elementary ballistics of the shotgun have been presented in the hope that an understanding of this weapon and the missiles it fires will aid in the surgical care of shotgun wounds.Variations in the wounds inflicted with this weapon are described as well as the apparent differences in sus
Creasing of an everted elastomer tube

A cylindrical elastomer tube can stay in an everted state without any external forces. If the thickness of the tube is small, the everted tube, except for the regions close to the free ends of the tube, maintains a cylindrical shape, and if the thickness is larger than a critical value, the cross-section of the everted tube becomes noncircular, which is caused by mechanical instability. Although eversion-induced instability in an elastomer tube has been reported several decades ago, a satisfying explanation of the phenomenon is still unavailable. In all previous studies, linear analyses have been adopted to predict the critical thickness of the tube for eversion-induced instability. The discrepancy between prediction and experiment is significant. In this communication, based on experiments and theoretical analyses, we show that crease formation on the inner surface of an everted tube is the mechanical instability mode, which cannot be captured by linear stability analyses. Instead, a combination of energetic analyses and numerical simulations of finite deformation in an everted tube enables us to correctly predict both the critical tube thickness for the onset of creases and the profile of the noncircular cross-section of an everted tube.
Learning under fear of floating

Abstract In recent years a large fraction of economies overcame the fear of floating. We study a model that describes the policy of a Central Bank uncertain about whether currency depreciations cause output to expand (textbook model) or contract (balance-sheet model). We conclude that the movement away from fear of floating may not be explained by Bayesian or Robust policies. When the private sector anticipates the Central Bank's policy and endogenously determines the model, Central Banks may fall in a learning trap. An increase in financial volatility provides an escape to such trap that replicates patterns in the data.
Perioperative management of patients on chronic antithrombotic therapy

Perioperative management of antithrombotic therapy is a situation that occurs frequently and requires consideration of the patient, the procedure, and an expanding array of anticoagulant and antiplatelet agents. Preoperative assessment must address each patient's risk for thromboembolic events balanced against the risk for perioperative bleeding. Procedures can be separated into those with a low bleeding risk, which generally do not require complete reversal of the antithrombotic therapy, and those associated with an intermediate or high bleeding risk. For patients who are receiving warfarin who need interruption of the anticoagulant, consideration must be given to whether simply withholding the anticoagulant is the optimal approach or whether a perioperative "bridge" with an alternative agent, typically a low-molecular-weight heparin, should be used. The new oral anticoagulants dabigatran and rivaroxaban have shorter effective half-lives, but they introduce other concerns for perioperative management, including prolonged drug effect in patients with renal insufficiency, limited experience with clinical laboratory testing to confirm lack of residual anticoagulant effect, and lack of a reversal agent. Antiplatelet agents must also be considered in the perioperative setting, with particular consideration given to the potential risk for thrombotic complications in patients with coronary artery stents who have antiplatelet therapy withheld.
A quantum correction to chaos

We use results on Virasoro conformal blocks to study chaotic dynamics in CFT2 at large central charge c. The Lyapunov exponent λ L , which is a diagnostic for the early onset of chaos, receives 1/c corrections that may be interpreted as $$ {\lambda}_L=\frac{2\pi }{\beta}\left(1+\frac{12}{c}\right) $$ . However, out of time order correlators receive other equally important 1/c suppressed contributions that do not have such a simple interpretation. We revisit the proof of a bound on λ L that emerges at large c, focusing on CFT2 and explaining why our results do not conflict with the analysis leading to the bound. We also comment on relationships between chaos, scattering, causality, and bulk locality.
Triacetic acid lactone as a common intermediate for the synthesis of 4-hydroxy-2-pyridones and 4-amino-2-pyrones

Abstract At ambient temperature, triacetic acid lactone reacts with amines to produce 4-amino-2-pyrones. If the temperature is raised to 100 °C, 4-hydroxy-2-pyridones are generated.
Genetic Variation, Not Cell Type of Origin, Underlies the Majority of Identifiable Regulatory Differences in iPSCs

The advent of induced pluripotent stem cells (iPSCs) revolutionized human genetics by allowing us to generate pluripotent cells from easily accessible somatic tissues. This technology can have immense implications for regenerative medicine, but iPSCs also represent a paradigm shift in the study of complex human phenotypes, including gene regulation and disease. Yet, an unresolved caveat of the iPSC model system is the extent to which reprogrammed iPSCs retain residual phenotypes from their precursor somatic cells. To directly address this issue, we used an effective study design to compare regulatory phenotypes between iPSCs derived from two types of commonly used somatic precursor cells. We find a remarkably small number of differences in DNA methylation and gene expression levels between iPSCs derived from different somatic precursors. Instead, we demonstrate genetic variation is associated with the majority of identifiable variation in DNA methylation and gene expression levels. We show that the cell type of origin only minimally affects gene expression levels and DNA methylation in iPSCs, and that genetic variation is the main driver of regulatory differences between iPSCs of different donors. Our findings suggest that studies using iPSCs should focus on additional individuals rather than clones from the same individual.
On the Existence of Epipolar Matrices

This paper considers the foundational question of the existence of a fundamental (resp. essential) matrix given m point correspondences in two views. We present a complete answer for the existence of fundamental matrices for any value of m. We disprove the widely held beliefs that fundamental matrices always exist whenever $$m \le 7$$m≤7. At the same time, we prove that they exist unconditionally when $$m \le 5$$m≤5. Under a mild genericity condition, we show that an essential matrix always exists when $$m \le 4$$m≤4. We also characterize the six and seven point configurations in two views for which all matrices satisfying the epipolar constraint have rank at most one.
Reporting Heterogeneity and Health Disparities Across Gender and Education Levels: Evidence From Four Countries

I use anchoring vignettes from Indonesia, the United States, England, and China to study the extent to which differences in self-reported health across gender and education levels can be explained by the use of different response thresholds. To determine whether statistically significant differences between groups remain after adjusting thresholds, I calculate standard errors for the simulated probabilities, largely ignored in previous literature. Accounting for reporting heterogeneity reduces the gender gap in many health domains across the four countries, but to varying degrees. Health disparities across education levels persist and even widen after equalizing thresholds across the two groups.
Development of a Northern Continental Air Standard Reference Material

The National Institute of Standards and Technology (NIST) recently began to develop standard mixtures of greenhouse gases as part of a broad program mandated by the 2009 United States Congress to support research in climate change. To this end, NIST developed suites of gravimetrically assigned primary standard mixtures (PSMs) comprising carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) in a dry-natural air balance at ambient mole fraction levels. In parallel, the National Oceanic and Atmospheric Administration (NOAA) in Boulder, Colorado, charged 30 aluminum gas cylinders with northern hemisphere air at Niwot Ridge, Colorado. These mixtures, which constitute NIST Standard Reference Material (SRM) 1720 Northern Continental Air, were certified by NIST for ambient mole fractions of CO2, CH4, and N2O relative to NIST PSMs. NOAA-assigned values are also provided as information in support of the World Meteorological Organization (WMO) Global Atmosphere Watch (GAW) Program for CO2, CH4, and N2O, since...
On the geometry of real or complex supersolvable line arrangements

Given a rank 3 real arrangement A of n lines in the projective plane, the Dirac-Motzkin conjecture (proved by Green and Tao in 2013) states that for n sufficiently large, the number of simple intersection points of A is greater than or equal to n / 2 . With a much simpler proof we show that if A is supersolvable, then the conjecture is true for any n (a small improvement of original conjecture). The Slope problem (proved by Ungar in 1982) states that n non-collinear points in the real plane determine at least n - 1 slopes; we show that this is equivalent to providing a lower bound on the multiplicity of a modular point in any (real) supersolvable arrangement. In the second part we find connections between the number of simple points of a supersolvable line arrangement, over any field of characteristic 0, and the degree of the reduced Jacobian scheme of the arrangement. Over the complex numbers even though the Sylvester-Gallai theorem fails to be true, we conjecture that the supersolvable version of the Dirac-Motzkin conjecture is true.
The Social Value of Financial Expertise

I study expertise acquisition in a model of trading under asymmetric information. I propose and implement a method to measure r, the ratio of the marginal social value to the marginal private value of expertise. This can be decomposed into three sufficient statistics: traders' average profits, the fraction of bad assets among traded assets, and the elasticity of good assets traded with respect to capital inflows. I measure r = 0.16 for the junk bond underwriting market. Since this is less than 1, it implies that marginal investments in expertise destroy surplus.
Signal/noise optimization strategies for stochastically estimated correlation functions

Numerical studies of quantum field theories usually rely upon an accurate determination of stochastically estimated correlation functions in order to extract information about the spectrum of the theory and matrix elements of operators. The reliable determination of such correlators is often hampered by an exponential degradation of signal/noise at late time separations. We demonstrate that it is sometimes possible to achieve significant enhancements of signal/noise by appropriately optimizing correlators with respect to the source and sink interpolating operators, and highlight the large range of possibilities that are available for this task. The ideas are discussed for both a toy model, and single hadron correlators in the context of quantum chromodynamics.
Quasi Linear Codes: Application to point-to-point and multi-terminal source coding

A new ensemble of structured codes is introduced. These codes are called Quasi Linear Codes (QLC). The QLC's are constructed by taking subsets of linear codes. They have a looser structure compared to linear codes and are not closed under addition. We argue that these codes provide gains in terms of achievable Rate-Distortions (RD) in different multi-terminal source coding problems. We derive the necessary covering bounds for analyzing the performance of QLC's. We then consider the Multiple-Descriptions (MD) problem, and prove through an example that the application of QLC's gives an improved achievable RD region for this problem. Finally, we derive an inner bound to the achievable RD region for the general MD problem which strictly contains all of the previous known achievable regions.
Sector heterogeneity and credit market imperfections in emerging markets

This paper shows that the impact of country interest rate shocks on emerging markets' economic activities can be associated with credit market imperfections affecting principally non-tradable activities. I present novel evidence documenting that tradable and non-tradable activities respond asymmetrically to changes in credit conditions in emerging markets. I show that country interest rate shocks are amplified through non-tradable activities, and that local credit substantially explains their output growth. Unlike the non-tradable sector, tradable activities are not significantly affected by changes in local credit conditions. To rationalize these findings, I introduce a small open economy model with heterogeneous access to international borrowing that accounts for the asymmetric response of tradable and non-tradable activities.
Rapid, Regioconvergent, Solvent-Free Alkene Hydrosilylation with a Cobalt Catalyst

Alkene hydrosilylation is typically performed with Pt catalysts, but inexpensive base-metal catalysts would be preferred. We report a Co catalyst for anti-Markovnikov alkene hydrosilylation that can be used without added solvent at low temperatures with low loadings, and can be generated in situ from an air-stable precursor that is simple to synthesize from low-cost, commercially available materials. In addition, a mixture of Co catalysts performs a tandem catalytic alkene isomerization/hydrosilylation reaction that converts multiple isomers of hexene to the same terminal product. This regioconvergent reaction uses isomerization as a benefit rather than a hindrance.
Jimbo: a collaborative IDE with live preview

Team collaboration plays a key role in the success of any multi- user activity. Software engineering is a highly collaborative activity, where multiple developers and designers work together to solve a common problem. Meaningful and effective designer- developer collaboration improves the user experience, which can improve the chances of success for the project. Learning to program is another activity that can be implemented in a more collaborative way, students can learn in an active style by working with others. The growth of online classes, from small structured seminars to massive open online courses (MOOCs), and the isolation and impoverished learning experience some students report in these, points to an urgent need for tools that support remote pair programming in a distributed educational setting. In this paper, we describe Jimbo, a collaborative integrated development environment (IDE) that we believe is beneficial and effective in both aforementioned activities. Jimbo integrates many features that support better collaboration and communication between designers and developers, to bridge communication gaps and develop mutual understanding. These novel features can improve today’s CS education by bringing students closer to each other and their instructors as well as training them to collaborate which is consistent with current practices in software engineering.