cssi/SciSciGPT-SciSciNet huggingface dataset:
Contributions of Selected Transcript Information to Prediction of Law School Performance.

Graduate and professional schools usually base their admissions decisions on a combination of test scores and on an overall index of undergraduate achievement such as cumulative grade-point average or rank-in-class. The present study sought to investigate whether considering more specific indices of undergraduate performance, through a detailed analysis of college transcripts, could lead to increased accuracy in predicting law school performance. Stepwise multiple regression analyses, performed separately for each of two schools, resulted in the selection of the LSAT, social science GPA, and a moderator variable as the most useful predictors. Because of the effects of selection, however, caution was urged in interpreting the results.
Cross-cutting Cleavages and Ethnic Voting: An Experimental Study of Cousinage in Mali

Social scientists often attribute moderation of the political salience of ethnicity in ethnically diverse societies to the presence of cross-cutting cleavages—that is, to dimensions of identity or interest along which members of the same ethnic group may have diverse allegiances. Yet, estimating the causal effects of cross-cutting cleavages is difficult. In this article, we present experimental results that help explain why ethnicity has a relatively minor political role in Mali, an ethnically heterogeneous sub-Saharan African country in which ethnic identity is a poor predictor of vote choice and parties do not form along ethnic lines. We argue that the cross-cutting ties afforded by an informal institution called “cousinage” help explain the weak association between ethnicity and individual vote choice. The experimental research design we introduce may be useful in many other settings.
Expenditures and Information Disclosure in Two-Stage Political Contests

This laboratory experiment studies two-stage contests between political parties. In the first stage, parties run their primaries, and in the second stage, the winners of the primaries compete in the general election. The resource expenditures in the first stage by the winning candidates are partially or fully carried over to the second stage. Experimental results support all major theoretical predictions: the first-stage expenditures and the total expenditures increase, while the second-stage expenditures decrease in the carryover rate. Consistent with the theory, the total expenditures increase in the number of candidates and the number of parties. Contrary to the theory, however, expenditures in both stages of the competition exceed theoretical predictions. Disclosing information about the opponent’s expenditures in the first stage increases the second-stage expenditures and decreases the first-stage expenditures.
Surface waves on interface of 3D metal-wire diamond lattice for accelerator applications

We present the results of our recent research on 3D metallic lattices operating at microwave frequencies, with applications in advanced accelerating structures and radiation sources based on the Smifh-Purcell effect. Bulk and surface electromagnetic waves supported by a diamond lattice of metal wires are calculated using HFSS. The bulk modes are determined using calculation of a primitive cell of diamond lattice. The surface mode is determined using simulation of a stack of cells with the perfect-matching layer boundary in vacuum. A plasmonic waveguide is formed as a defect in a diamond lattice. The plasmonic waveguide mode can be employed for particle acceleration.
Synthesis of Mono- and Symmetrical Di-N-hydroxy- and N-Aminoguanidines

Novel mono- and symmetrical di-N-hydroxy- and N-aminoguanidines were readily prepared from the reaction of diverse hydroxylamines or hydrazines with reagent classes di(benzotriazol-1-yl)methanimine 6, (bis-benzotriazol-1-yl-methylene)amines 8a,b, benzotriazole-1-carboxamidines 10a−i, benzotriazole-1-carboximidamides 11a,b, and N‘-hydroxy-1H-1,2,3-benzotriazole-1-carboximidamide 18. The preparation is described for a variety of N-hydroxy- and N-aminoguanidines with different substitution patterns in good yields.
Synthesis and crystallographic structure of a novel photoresponsive azobenzene-containing organosilane

A novel photoresponsive azobenzene-containing organosilane was synthesized via an isocyanato-amino coupling reaction, and its crystal structure was determined by X-ray crystallography.
Approximate queries and representations for large data sequences

Many new database application domains such as experimental sciences and medicine are characterized by large sequences as their main form of data. Using approximate representation can significantly reduce the required storage and search space. A good choice of representation, can support a broad new class of approximate queries, needed in there domains. These queries are concerned with application dependent features of the data as opposed to the actual sampled points. We introduce a new notion of generalized approximate queries and a general divide and conquer approach that supports them. This approach uses families of real-valued functions as an approximate representation. We present an algorithm for realizing our technique, and the results of applying it to medical cardiology data.
Quantum dynamics in strong fluctuating fields

A large number of multifaceted quantum transport processes in molecular systems and physical nanosystems, such as e.g. nonadiabatic electron transfer in proteins, can be treated in terms of quantum relaxation processes which couple to one or several fluctuating environments. A thermal equilibrium environment can conveniently be modelled by a thermal bath of harmonic oscillators. An archetype situation provides a two-state dissipative quantum dynamics, commonly known under the label of a spin-boson dynamics. An interesting and nontrivial physical situation emerges, however, when the quantum dynamics evolves far away from thermal equilibrium. This occurs, for example, when a charge transferring medium possesses nonequilibrium degrees of freedom, or when a strong time-dependent control field is applied externally. Accordingly, certain parameters of underlying quantum subsystem acquire stochastic character. This may occur, for example, for the tunnelling coupling between the donor and acceptor states of the t...
Southeast Asian Agriculture Returns to Scale: Inferences from Cumulative Rolling Stochastic Frontier Analysis

In this paper, we estimate the time-varying betas or input elasticities and returns to scale in a stochastic frontier cumulative rolling regression analysis framework using FAO data of Southeast Asian countries from 1960-2002. Empirical results indicated returns to scale are overestimated by pooled and panel models relative to stochastic frontier models without accounting for technical inefficiencies. Second, the time-varying estimates of betas or input elasticities and returns to scale indicate variations not only between the models but also over time.
Statistical Path Selection for At-Speed Test

Process variations make at-speed testing significantly more difficult. They cause subtle delay changes that are distributed in contrast to the localized nature of a traditional fault model. Due to parametric variations, different paths can be critical in different parts of the process space, and the union of such paths must be tested to obtain good process space coverage. This paper proposes an integrated at-speed structural testing methodology, and develops a novel branch-and-bound algorithm that elegantly and efficiently solves the hitherto open problem of statistical path tracing. The resulting paths are used for at-speed structural testing. A new test quality metric is proposed, and paths which maximize this metric are selected. After chip timing has been performed, the path selection procedure is extremely efficient. Path selection for a multimillion gate chip design can be completed in a matter of seconds.
Cobaltate anion couples terminal dienes with trifluoroacetic anhydride: a direct fluoroacylation of 1,3-dienes

Perfluoroketones are useful products and intermediates in medicinal chemistry. Herein, cobalt-mediated fluoroacylation of 1,3-dienes is described using perfluorinated anhydrides such as TFAA. The reaction is thought to proceed through a fluoroacylcobalt reagent formed in situ. Perfluoroacylation of 1,3 dienes can also be performed to attain longer chain perfluorinated ketones.
Mathematical Programming and Economic Theory

This paper, which is based on the remarks offered during a plenary address at the May 1989 CORS/TIMS/ORSA meeting in Vancouver, discusses the analogy between economic institutions and algorithms for solving mathematical programming problems. The simplex method for solving linear programs can be interpreted as a search for market prices that equilibrate the demand for factors of production with their supply. A possible interpretation in terms of the internal organization of a large firm is offered for Lenstra's integer programming algorithm.
The Legacy of the Tevatron in the Area of Accelerator Science

For more than 25 years, the Tevatron was the highest-energy accelerator in the world. It provided the first access to particle collisions beyond 1 TeV and achieved an ultimate performance that was a factor of 400 beyond the original design goals. This article reviews the many formidable challenges that were overcome, and the knowledge gained, in building, operating, and improving the Tevatron during its lifetime. These challenges included the first operation of an accelerator based on superconducting magnets; production of antiprotons in sufficient numbers to support a usable luminosity; management of beam–beam, intrabeam, and other collective effects; novel manipulations of the beam longitudinal phase space; and development and application of a wide variety of innovative technologies. These achievements established the legacy of the Tevatron as the progenitor of all subsequently constructed high-energy hadron colliders.
ADAPTIVE EXPECTATIONS AND STOCK MARKET CRASHES

A theory is developed that explains how stocks can crash without fundamental news and why crashes are more common than frenzies. A crash occurs via the interaction of rational and naive investors. Naive traders believe that prices follow a random walk with serially correlated volatility. Their expectations of future volatility are formed adaptively. When the market crashes, naive traders sell stock in response to the apparent increase in volatility. Since rational traders are risk averse as well, a lower price is needed to clear the market: The crash is a self-fulfilling prophecy. Frenzies cannot occur in this model.
Catalytic Asymmetric Synthesis of 8‐Oxabicyclooctanes by Intermolecular [5+2] Pyrylium Cycloadditions

Highly enantioselective intermolecular [5+2] cycloadditions of pyrylium ion intermediates with electron-rich alkenes are promoted by a dual catalyst system composed of an achiral thiourea and a chiral primary aminothiourea. The observed enantioselectivity is highly dependent on the substitution pattern of the 5π component, and the basis for this effect is analyzed using experimental and computational evidence. The resultant 8-oxabicyclo[3.2.1]octane derivatives possess a scaffold common in natural products and medicinally active compounds and are also versatile chiral building blocks for further manipulations. Several stereoselective complexity-generating transformations of the 8-oxabicyclooctane products are presented.
Preparing university students for global workforces: Comparisons between engineering and business school students

There is a growing concern among universities that students in undergraduate and graduate engineering and business programs will be unprepared or underprepared to work in global workforces. In their 2005 publication, Engineers for 2020, the National Academy of Engineering (NAE) urged university engineering schools nationwide to embed curriculum and assessment measures into academic programs that provide opportunities and associated assessment metrics to meet this international challenge. Specifically, the NAE charges universities and colleges to prepare engineers that are leaders in global engineering fields with strong communication, leadership and interdisciplinary research, and professional skills in diverse in engineering environments. Businesses, and business school have similar globally focused charges. This paper describes a university's response to an important challenge of preparing students for global workforces. This paper describes assessment metrics related to preparedness for working in diverse globally focused engineering and business contexts. In this study, engineering and business school students received interdisciplinary globally focused training via their coursework, research and international field experiences and were assessed as to their preparedness to work in global workforces, research, and diverse environments. Accordingly, global preparedness index was developed and administered to assess the impact of diverse educational and research experiences summatively. Results of this important assessment metric were compared across programs and to students' course grades, work related efficacy, international field experiences and outcomes-based academic program success. Results of this research indicate that engineering and business students who were most globally prepared were also most efficacious, had international experiences, and received higher grades in courses. Additionally, diversity in preparedness among the subscales of the index was noted, suggesting that students with diverse socio-demographic profiles had diverse preparedness indices.
An Adaptive Initial Trust and Demand Aware Secure Resource Discovery (AID-SRD) model for pervasive environments

Traditional computer systems and small distributed networks rely on users' authentication to provide security. However, this strategy is extremely inadequate for the increased flexibility of pervasive environments, where users join and leave frequently. Here, users want to discover services dynamically and share them safely taking into account some constraints such as limited computational power and decentralized management. In this paper, we propose a solution to this using a secure resource discovery model. Most of the prior research works on resource discovery assume a constant initial trust value because assignment of initial trust is a critical issue. Even in pervasive smart space, some service sharing may need high security. The level of service security therefore needs to be incorporated in initial trust assignment. In this paper, we present an Adaptive Initial trust and Demand aware Secure Resource Discovery (AID-SRD) model for pervasive environment. We incorporate a Demand Unit in AID-SRD which enables efficient resource sharing with unknown devices. AIDSRD also assigns initial trust considering the variable security need of different services.
New dynamics and dualities in supersymmetric chiral gauge theories

We analyze the phase structure of supersymmetric chiral gauge theories with gauge group SU(N), an antisymmetric, and F ≤ N + 3 flavors, in the presence of a cubic superpotential. When F = N + 3 the theory flows to a superconformal fixed point in the infrared, and new dual descriptions of this theory are uncovered. The theory with odd N admits a self-dual magnetic description. For general N, we find an infinite family of magnetic dual descriptions, characterized by arbitrarily large gauge groups and additional classical global symmetries that are truncated by nonperturbative effects. The infrared dynamics of these theories are analyzed using a-maximization, which supports the claim that all these theories flow to the same superconformal fixed point. A very rich phase structure is found when the number of flavors is reduced below N + 3, including a new self-dual point, transitions from conformal to confining, and a nonperturbative instability for F ≤ N. We also give examples of chiral theories with antisymmetrics that have nonchiral duals.
Dealer versus auction markets: A paired comparison of execution costs on NASDAQ and the NYSE

Abstract Execution costs, as measured by the quoted spread, the effective spread (which accounts for trades inside the quotes), the realized spread (which measures revenues of suppliers of immediacy), the Roll (1984) implied spread, and the post-trade variability, are twice as large for a sample of NASDAQ stocks as they are for a matched sample of NYSE stocks. The difference is not due to differences in adverse information, in market depth, or in the frequency of even-eighth quotes. Partial explanations are provided by differences in the treatment of limit orders and commissions in the two markets. We conclude that important explanations are the internalization and preferencing of order flow and the presence of alternative interdealer trading systems, factors that limit dealers' incentives to narrow spreads on NASDAQ.
Evidence on Corporate Hedging Policy

This paper provides empirical evidence on the determinants of corporate hedging decisions. The paper examines the evidence in light of currently mandated financial reporting requirements and, in particular, the constraints placed on anticipatory hedging. Data on hedging are obtained from 1992 annual reports for a sample of 3,022 firms. Out of the 771 firms classified as hedgers, 543 firms disclose information in their annual reports on their hedging activities; the remaining 228 firms report use of derivatives but no information on hedging activities. Based on the evidence, I draw the following conclusions with respect to the models of hedging: evidence is inconsistent with financial distress cost models; evidence is mixed with respect to contracting cost, capital market imperfections, and tax-based models; and evidence uniformly supports the hypothesis that hedging activities exhibit economies of scale.
Worms at Work: Long-run Impacts of a Child Health Investment

This study estimates long-run impacts of a child health investment, exploiting community-wide experimental variation in school-based deworming. The program increased labor supply among men and education among women, with accompanying shifts in labor market specialization. Ten years after deworming treatment, men who were eligible as boys stay enrolled for more years of primary school, work 17% more hours each week, spend more time in nonagricultural self-employment, are more likely to hold manufacturing jobs, and miss one fewer meal per week. Women who were in treatment schools as girls are approximately one quarter more likely to have attended secondary school, halving the gender gap. They reallocate time from traditional agriculture into cash crops and nonagricultural self-employment. We estimate a conservative annualized financial internal rate of return to deworming of 32%, and show that mass deworming may generate more in future government revenue than it costs in subsidies.
Circulation shedding in viscous starting flow past a flat plate

Numerical simulations of viscous flow past a flat plate moving in the direction normal to itself reveal details of the vortical structure of the flow. At early times, most of the vorticity is attached to the plate. This paper introduces a definition of the shed circulation at all times and shows that it indeed represents vorticity that separates and remains separated from the plate. During a large initial time period, the shed circulation satisfies the scaling laws predicted for self-similar inviscid separation. Various contributions to the circulation shedding rate are presented. The results show that during this initial time period, viscous diffusion of vorticity out of the vortex is significant but appears to be independent of the value of the Reynolds number. At later times, the departure of the shed circulation from its large Reynolds number behaviour is significantly affected by diffusive loss of vorticity through the symmetry axis. A timescale is proposed that describes when the viscous loss through the axis becomes relevant. The simulations provide benchmark results to evaluate simpler separation models such as point vortex and vortex sheet models. A comparison with vortex sheet results is included.
Nanotechnology and Society : A discussion-based undergraduate course

Nanotechnology has emerged as a broad, exciting, yet ill-defined field of scientific research and technological innovation. There are important questions about the technology’s potential economic, social, and environmental implications. We discuss an undergraduate course on nanoscience and nanotechnology for students from a wide range of disciplines, including the natural and social sciences, the humanities, and engineering. The course explores these questions and the broader place of technology in contemporary societies. The course is built around active learning methods and seeks to develop the students’ critical thinking skills, written and verbal communication abilities, and general knowledge of nanoscience and nanoengineering concepts. Continuous assessment was used to gain information about the effectiveness of class discussions and enhancement of student understanding of the interaction between nanotechnology and society.
Smart Projectile State Estimation Using Evidence Theory

Smart projectile state estimation is a challenging task due to highly nonlinear vehicle dynamic behavior and unreliable or noisy sensor feedback. While Kalman filter-based algorithms are currently the primary means of sensor fusion and state estimation for smart weapons applications, they are limited in estimation accuracy, their ability to combine data from a wide variety of sensors, and their ability to recognize and reject erroneous feedback. This paper explores the use of Evidence Theory (or DempsterShafer theory) for projectile state estimation purposes. Evidence Theory offers a generalized framework capable of incorporating feedback from a wide variety of sensors with little a priori knowledge about sensor noise characteristics. The framework’s main strengths are its ability to manage varying levels of dynamic uncertainty between sensors and its capability to recognize and report conflicting sensor feedback. The paper begins with an overview of Evidence Theory and a discussion of its strengths when applied to projectile state estimation. Then, an Evidence Theorybased filter is described, and an example roll angle estimator is presented. Results are discussed and performance is compared to an Extended Kalman filter. The ability to identify and eliminate malfunctioning sensors from the estimation process proves to be a key advantage of the proposed design over current methods.
Penalized maximum-likelihood image reconstruction using space-alternating generalized EM algorithms

Most expectation-maximization (EM) type algorithms for penalized maximum-likelihood image reconstruction converge slowly, particularly when one incorporates additive background effects such as scatter, random coincidences, dark current, or cosmic radiation. In addition, regularizing smoothness penalties (or priors) introduce parameter coupling, rendering intractable the M-steps of most EM-type algorithms. This paper presents space-alternating generalized EM (SAGE) algorithms for image reconstruction, which update the parameters sequentially using a sequence of small "hidden" data spaces, rather than simultaneously using one large complete-data space. The sequential update decouples the M-step, so the maximization can typically be performed analytically. We introduce new hidden-data spaces that are less informative than the conventional complete-data space for Poisson data and that yield significant improvements in convergence rate. This acceleration is due to statistical considerations, not numerical overrelaxation methods, so monotonic increases in the objective function are guaranteed. We provide a general global convergence proof for SAGE methods with nonnegativity constraints. >
Public goods and government action

It is widely agreed that one of the core functions of government is to supply public goods that markets either fail to provide or cannot provide efficiently. I will suggest that arguments for government provision of public goods require fundamental moral judgments in addition to the usual economic considerations about the relative efficacy of markets and governments in supplying them. While philosophers and policymakers owe a debt of gratitude to economists for developing the theory of public goods, the link between public goods and public policy cannot be forged without moral reflection on the proper function and scope of government power.
The descriptive epidemiology of commonly occurring mental disorders in the United States.

Data are reviewed on the descriptive epidemiology of commonly occurring DSM-IV mental disorders in the United States. These disorders are highly prevalent: Roughly half the population meets criteria for one or more such disorders in their lifetimes, and roughly one fourth of the population meets criteria in any given year. Most people with a history of mental disorder had first onsets in childhood or adolescence. Later onsets typically involve comorbid disorders. Some anxiety disorders (phobias, separation anxiety disorder) and impulse-control disorders have the earliest age of onset distributions. Other anxiety disorders (panic disorder, generalized anxiety disorder, post-traumatic stress disorder), mood disorders, and substance disorders typically have later ages of onset. Given that most seriously impairing and persistent adult mental disorders are associated with child-adolescent onsets and high comorbidity, increased efforts are needed to study the public health implications of early detection and tr...
The Efficiency of the Global Markets for Final Goods and Productive Capabilities

Slow mean reversion of real exchange rates is commonly considered a result of border frictions that remain despite integration of financial and goods markets. This paper shows that even if border frictions decline, a contemporaneous decline in output shock variance can in fact slow down mean reversion. It proposes a new method of estimating border cost from time-series data only, without relying on within-country variation. Applying this method to the real exchange rate of final goods and a novel measure of the real exchange rate for productive capabilities, such as technology and know-how, gives very differential border cost estimates. During the years 1974–2008, a relocation reduces productive capability by 22% for the average country pair, whereas final goods by only 15%. The real exchange rate for final goods takes more than two years to revert to purchasing power parity, more than twice as long as productive capabilities.
Building rational cooperation

Experiments have shown that people have a natural taste for cooperation. This paper takes a first step in understanding how formal and informal institutions might be designed to utilize these private tastes to facilitate more efficient economic interactions. We examine a twice-played prisoners’ dilemma in which the total of the stakes in the two periods is fixed, but the distribution of these stakes can be varied across periods. We verify experimentally that it is best to “start small,” reserving most of the stakes for the second period.
Does Gokana really have no syllables? Or: what's so great about being universal?*

UC Berkeley Phonology Lab Annual Report (2010) Does Gokana Really Have No Syllables? (Or: What’s So Great About Being Universal?) Larry M. Hyman University of California, Berkeley May, 2010 ABSTRACT Over 25 years ago, Hyman (1983, 1985) made the claim that Gokana, an Ogoni (Niger-Congo) language of Nigeria, does not organise its consonants and vowels into syllables. This was a radical and in principle non-welcome position, given the centrality of the syllable in almost all phonological work at the time. Still, as Richard Hayward pointed out many years later, the extensive treatment of Gokana largely went unnoticed: Hyman's account of the Nigerian language Gokana and in particular his well-argued claim that Gokana represents a case where invocation of the syllable buys nothing insightful for explaining the phonology of the language should have disturbed profoundly the settled orthodoxy surrounding the universality of the syllable. That a vowel (the quintessential syllable nucleus) is not guaranteed syllable membership is a very strong proposal, but one has little sense that it has attracted overmuch comment.… In my view it would be unfortunate if Gokana were to be regarded simply as an interesting oddity, rather than as the limiting case in a clinal situation in which many languages may participate to some degree in the course of their phonologies. (Hayward 1997:78) While there was almost no response to the claim of no syllables in Gokana, the proposal of Hyman (1983, 1985) to establish moras as a central building block in phonology did gain currency, and was particularly welcome by specialists of Japanese, long viewed as exclusively moraic in its prosodic structure. Since that time work on the syllable has gone in opposite directions: While Kubozono (1999, 2003) has presented evidence that the syllable may in fact play a role in Japanese, Steriade (1999) and Blevins (2003) have argued that the syllable is less needed elsewhere, e.g. to account for phonotactic constraints and perhaps certain rhythmic effects (Steriade 2009). It seems that the status of the syllable is thus once again up for grabs, as has been the case in its rocky on-again, off-again past. In this paper I take a new look at the Gokana facts and the original claim to ask the question in my title, motivated in part by overlooked (possibly ambiguous) evidence for the syllable in Gokana. The paper will end by situating the issue within the context of recent discussions of universals vs. diversity (Evans & Levinson 2009), with my claim that English and Gokana are at the opposite ends of the “clinal situation” which Hayward suspected in the above quote. * Earlier versions of this paper were presented at the University of California, Berkeley, the Laboratoire Dynamique du Langage (Lyon), and at the Queen Mary University of London Workshop on Tones and Prosodic Constituents (March 25-6, 2010).
High-performance computing: clusters, constellations, MPPs, and future directions

In a recent paper, Gordon Bell and Jim Gray (2002) put forth a view of the past, present, and future of high-performance computing (HPC) that is both insightful and thought provoking. Identifying key trends with a grace and candor rarely encountered in a single work, the authors describe an evolutionary past drawn from their vast experience and project an enticing and compelling vision of HPC's future. Yet, the underlying assumptions implicit in their treatment, particularly those related to terminology and dominant trends, conflict with our own experience, common practices, and shared view of HPCs future directions. Taken from our vantage points of the Top500 list," the Lawrence Berkeley National Laboratory NERSC computer center, Beowulf-class computing, and research in petaflops-scale computing architectures, we offer an alternate perspective on several key issues in the form of a constructive counterpoint. One objective of this article is to restore the strength and value of the term "cluster" by degeneralizing its applicability to a restricted subset of parallel computers. We'll further consider this class in conjunction with its complementing terms constellation, Beowulf class, and massively parallel processing systems (MPPs), based on the classification used by the Top500 list, which has tracked the HPC field for more than a decade.
Rhodium-catalyzed oxidative amidation of allylic alcohols and aldehydes: effective conversion of amines and anilines into amides

The rhodium-catalyzed oxidative amidation of allylic alcohols and aldehydes is reported. In situ generated [(BINAP)Rh]BF4 catalyzes the one-pot isomerization/oxidative amidation of allylic alcohols or direct amidation of aldehydes using acetone or styrene as the hydrogen acceptor. The conditions are general, affording good to excellent yields with a wide array of amine and aniline nucleophiles, and chemoselective, other alcohols do not participate in the oxidation reaction. Utilization of biphasic conditions is critical, as they promote an equilibrium between the imine/enamine byproducts and the hemiaminal, which can undergo oxidation to the amide.
Spiral dynamics in pattern-forming systems: mean-flow effects

Abstract Mean-flow effects are discussed for two different pattern-forming systems: Rayleigh–Benard convection and Faraday instability in viscous fluid. In both systems spirals are observed in certain parameter regions. In the Rayleigh–Benard convection, the spiral-core instability is shown to occur due to the mean flow generated by the curved rolls near the core. In the Faraday instability, the mean flow which is generated by rapidly decaying surface waves near the wall, causes wave number frustration which leads to a rigid-body spiral rotation. In both cases we use phenomenological Swift–Hohenberg-type equations for the order parameter coupled to a large-scale mean flow. Numerical simulations are compared to recently reported experimental results.
Triethylborane-Initiated Room Temperature Radical Addition of Hypophosphites to Olefins: Synthesis of Monosubstituted Phosphinic Acids and Esters

A novel and practical approach to monosubstituted phosphinic acid (alkylphosphonous acid) derivatives from hypophosphite salts or esters is described. Phosphorus-centered radical formation is initi...
A New Test of Borrowing Constraints for Education

We discuss a simple model in which parents and children make investments in the childrens education, investments for other purposes, and parents can transfer cash to their children. We show that for an identifiable set of parent-child pairs, parents will rationally under-invest in their childs education. For these parent-child pairs, additional financial aid will increase educational attainment. The model highlights an important feature of higher education finance, the "expected family contribution" (EFC) that is based on income, assets, and other factors. The EFC is neither legally guaranteed nor universally offered: Our model identifies the set of families that are disproportionately likely to not provide their full EFC. Using a common proxy for financial aid, we show, in data from the Health and Retirement Study, that financial aid increases the educational attainment of children whose families are disproportionately likely to under-invest in education. Financial aid has no effect on the educational attainment of children in other families. The theory and empirical evidence identifies a set of children who face quantitatively important borrowing constraints for higher education.
Three-dimensional Compressible Hydrodynamic Simulations of Vortices in Disks

We carry out three-dimensional, high-resolution (up to 10242 × 256) hydrodynamic simulations of the evolution of vortices in vertically unstratified Keplerian disks using the shearing sheet approximation. The transient amplification of incompressible, linear amplitude leading waves (which has been proposed as a possible route to nonlinear hydrodynamic turbulence in disks) is used as one test of our algorithms; our methods accurately capture the predicted amplification, converge at second order, and are free from aliasing. Waves that are expected to reach nonlinear amplitude at peak amplification become unstable to Kelvin-Helmholtz modes when Wmax Ω (where Wmax is the local maximum of vorticity and Ω the angular velocity). We study the evolution of a power-law distribution of vorticity consistent with Kolmogorov turbulence; in two dimensions long-lived vortices emerge and decay slowly, similar to previous studies. In three dimensions, however, vortices are unstable to bending modes, leading to rapid decay. Only vortices with a length-to-width ratio smaller than 1 survive; in three dimensions the residual kinetic energy and shear stress is at least 1 order of magnitude smaller than in two dimensions. No evidence for sustained hydrodynamic turbulence and transport is observed in three dimensions. Instead, at late times the residual transport is determined by the amplitude of slowly decaying, large-scale vortices (with horizontal extent comparable to the scale height of the disk), with additional contributions from nearly incompressible inertial waves possible. Evaluating the role that large-scale vortices play in astrophysical accretion disks will require understanding the mechanisms that generate and destroy them.
Metadata aggregation and "automated digital libraries": a retrospective on the NSDL experience

Over three years ago, the Core Integration team of the National Science Digital Library (NSDL) implemented a digital library based on metadata aggregation using Dublin Core and OAI-PMH. The initial expectation was that such low-barrier technologies would be relatively easy to automate and administer. While this architectural choice permitted rapid deployment of a production NSDL, our three years of experience have contradicted our original expectations of easy automation and low people cost. We have learned that alleged "low-barrier" standards are often harder to deploy than expected. In this paper we report on this experience and comment on the general cost, the functionality, and the ultimate effectiveness of this architecture.
D-Branes And K-Theory

By exploiting recent arguments about stable nonsupersymmetric D-brane states, we argue that D-brane charge takes values in the K-theory of spacetime, as has been suspected before. In the process, we gain a new understanding of some novel objects proposed recently - such as the Type I zerobrane - and we describe some new objects - such as a -1-brane in Type I superstring theory.
Direct Simulation Based Model-Predictive Control of Flow Maldistribution in Parallel Microchannels

Flow maldistribution, resulting from bubbles or other particulate matter, can lead to drastic performance degradation in devices that employ parallel microchannels for heat transfer. In this work, direct numerical simulations of fluid flow through a prescribed parallel microchannel geometry are performed and coupled with active control of actuated microvalves to effectively identify and reduce flow maldistribution. Accurate simulation of fluid flow through a set of three parallel microchannels is achieved utilizing a fictitious-domain representation of immersed objects such as microvalves and artificially introduced bubbles. Flow simulations are validated against experimental results obtained for flow through a single high-aspect ratio microchannel, flow around an oscillating cylinder, and flow with a bubble rising in an inclined channel. Results of these simulations compare very well to those obtained experimentally, and validate the use of the solver for the parallel microchannel configuration of this study. System identification techniques are employed on numerical simulations of fluid flow through the geometry to produce a lower dimensional model that captures the essential dynamics of the full nonlinear flow, in terms of a relationship between valve angles and the exit flow rate for each channel. A model-predictive controller is developed, which employs this reduced order model to identify flow maldistribution from exit flow velocities and to prescribe actuation of channel valves to effectively redistribute the flow. Flow simulations with active control are subsequently conducted with artificially introduced bubbles. The model-predictive control methodology is shown to adequately reduce flow maldistribution by quickly varying channel valves to remove bubbles and to equalize flow rates in each channel.
Effects of LO Phase and Amplitude Imbalances and Phase Noise on $M$ -QAM Transceiver Performance

This paper presents a rigorous analytical model for analyzing the effects of local oscillator output imperfections such as phase/amplitude imbalances and phase noise on M -ary quadrature amplitude modulation (M-QAM) transceiver performance. A closed-form expression of the error vector magnitude (EVM) and an analytic expression of the symbol error rate (SER) are derived considering a single-carrier linear transceiver link with additive white Gaussian noise channel. The proposed analytical model achieves a good agreement with the simulation results based on the Monte Carlo method. The proposed QAM imperfection analysis model provides an efficient means for system and circuit designers to analyze the wireless transceiver performance and specify the transceiver block specifications.
Nonlinear dynamic maximum power theorem

The problem of maximizing the energy or average power transfer from a nonlinear dynamic source is considered. The main theorem includes, as special cases, the standard linear result where the load admittance equals the complex conjugate of the source admittance and a recent finding for linear resistive networks. An operator equation for the optimal output voltage is derived, and a numerical method for solving it is given. >
Reexamining the Role of Gifted Education and Talent Development for the 21st Century: A Four-Part Theoretical Approach.

Why and how should a society devote special resources to the development of giftedness in young people for the twenty-first century? If we agree that the goals of gifted education and talent development are to maximize young people's opportunities for self-fulfillment and increase society's reservoir of creative problem solvers and producers of knowledge, then it would seem wise that programming and services enhance students' capacity for creative productivity, not just content acquisition. This general theory for the development of human potential is discussed through an exploration of four research-based subtheories: the Three-Ring Conception of Giftedness, the Enrichment Triad Model, Operation Houndstooth, and Executive Functions. In this article, a reexamination of current gifted and talented programming is intended to generate future research, extend dialogue among scholars, and inspire continued support for programming based on theory and related research.
Retrieval from captioned image databases using natural language processing

It might appear that natural language processing should improve the accuracy of information retrieval systems, by making available a more detailed analysis of queries and documents. Although past results appear to show that this is not so, if the focus is shifted to short phrases rather than full documents, the situation becomes somewhat different. The ANVIL system uses a natural language technique to obtain high accuracy retrieval of images which have been annotated with a descriptive textual caption. The natural language techniques also allow additional contextual information to be derived from the relation between the query and the caption, which can help users to understand the overall collection of retrieval results. The techniques have been successfully used in a information retrieval system which forms both a testbed for research and the basis of a commercial system.
The multiple dimensions of male social status in an Amazonian society.

While social-status hierarchies are common to all human societies, status acquisition is relatively understudied in small-scale societies lacking significant material wealth or intergenerational inheritance. Among the Tsimane of Bolivia, a small-scale Amazonian society, we employ a photo-ranking methodology to determine the important predictors of four measures of male social status: success in dyadic physical confrontation, getting one's way in a group, community-wide influence, and respect. The predictors evaluated include age, physical size, skill in food production, level of acculturation, prosocial personality, and social support. We find that physical size best predicts rankings of dyadic fighting ability while social support best predicts getting one's way in a group, community-wide influence, and respect. Level of acculturation, furthermore, is an independent predictor of influence but not respect, and skill in food production is an independent predictor of respect but not influence. The lack of a linear relationship between age and the polyadic social-status measures is evaluated in light of the increasing exposure of the Tsimane to market economies and public education among recent age cohorts. To our knowledge, this study is the first multivariate analysis of social status that considers different determinants of status simultaneously.
Specular Surface Stereo: A New Method For Retrieving the Shape of a Water Surface

In many remote sensing applications the shape of a water surface must be determined instantaneously, and under natural lighting conditions. Most stereo image analysis techniques, however, assume surface reflectance properties which are. incompatible with the reflectance properties of water, especially in the centimeter and smaller wave lengths. To analyze the fine scale structure of the ocean surface, a new Specular Surface Stereo technique is presented that makes use of the unique optical properties of water. The method analyzes an image of the illumination source and multiple images of the water surface, and incorporates an image synthesis model that predicts the irradiance at a pixel for a given surface shape and illumination source. The surface shape is determined by solving the inverse problem of finding a surface elevation and gradient map that will result in a set of synthetic images that closely match the observed images. The performance of the Specular Surface Stereo technique and a conventional stereo analysis technique were tested by processing simulated data. Comparison of the two techniques showed that the Specular Surface Stereo method can potentially recover significantly more information than conventional stereo images analysis methods.
Minimizing Photodiode Nonlinearities by Compensating Voltage-Dependent Responsivity Effects

Two voltage-dependant responsivity effects, impact ionization and Franz-Keldysh oscillations, are shown to have opposing effects at certain wavelengths in p-i-n photodiodes. It is shown that these two effects can compensate each other and minimize photodiode nonlinearities when optimized with respect to wavelength and bias voltage.
High-brightness electron injectors: a review

The approaches now being explored for attaining intense, bright electron beams are described. The methods for producing bright electron beams include photocathode-based short-pulse injectors; DC electrostatic accelerator sources; long-pulse beams, which are then compressed in time using subharmonic bunching; combining first and third harmonics in an accelerator to attain the equivalent of high-gradient DC fields; and LaB/sub 6/ RF guns. For several of the approaches, the temporal length of the electron pulse is decreased after acceleration to relativistic energies by impressing an energy spread on the electron bunch and using a nonisochronous beam-transport system to increase the peak current. >
Microwave Imaging of Cotton Bales.

Modern moisture restoration systems are increasingly capable of adding water to cotton bales. However, research has identified large variations in internal moisture within bales that are not readily monitored by current systems. While microwave moisture sensing systems can measure average bale moisture, this can be deceptive where water is unevenly distributed. In some cases, localized internal moisture levels exceed 7.5%, the upper safe limit for cotton bale storage, as determined by the USDA, as above this level, bales degrade and lose value. A high proportion of stored bales containing excess moisture have been discovered throughout the US in increasing numbers over the past several seasons, making the detection and prevention of this occurrence a critical goal. Previous research by the authors resulted in the development of microwave moisture-sensing technology. The current study examines an extension to this technology to allow for detailed cotton bale moisture imaging. The new technique incorporates a narrow beam imaging antenna coupled to a tomographic imaging algorithm. The imaging technique was able to resolve small ( 0.99). In preliminary testing on a wet commercial UD bale, the technique was able to accurately image and resolve the location of the pre-placed internal wet layer.