cssi/SciSciGPT-SciSciNet huggingface dataset:
Predicting MBA Student Success and Streamlining the Admissions Process

Within this study the author examines factors commonly employed as master of business administration applicant evaluation criteria to see if these criteria are important in determining an applicant's potential for success. The findings indicate that the Graduate Management Admissions Test (GMAT) is not a significant predictor of student success when considering factors such as undergraduate grade point average and work experience. Furthermore, the results suggest that prior findings in support of the GMAT are the result of missing variables in the model specification. Our results show that undergraduate grade point average alone can be employed as an admission criterion and indicator of potential success in lieu of the GMAT; adopting this criterion instead can streamline the admission process while minimizing student expenses. Within the discussion section the author offers suggestions for reducing the need for the GMAT score information in the admissions process.
Community Ecology and the Sociology of Organizations

Research on organizations is increasingly informed by analysis of community context. Community can be conceptualized as sets of relations between organizational forms or as places where organizations are located in resource space or in geography. In both modes, organizations operate interdependently with social institutions and with other units of social structure. Because such relationships channel flows of resources, opportunities are granted or withheld from social actors depending in part on their organization connections. Such considerations encourage analyses of organizations in ways that spread the relevance of results beyond organizationally defined research problem areas.
Variable-field permanent-magnet dipole

A new concept for a variable-field permanent-magnet dipole (VFPMD) has been designed, fabricated, and tested. The VFPMD is a C-shaped sector magnet with iron poles separated by a large block of magnet material (SmCo). The central field can be continuously varied from 0.07 T to 0.3 T by moving an iron shunt closer or further away from the back of the magnet. The shunt is specially shaped to make the dependence of the dipole field on the shunt position as linear as possible. The dipole has a 2.8 cm-high by 8 cm-wide aperture with /spl sim/10 cm-long poles. >
Nickel-catalyzed amination of aryl sulfamates.

Carbon–nitrogen bonds are ubiquitous in medicinal agents and natural products.[1] Transition metal-catalyzed amination reactions, pioneered by Buchwald and Hartwig, are amongst the most powerful methods available for accessing these motifs.[1] Copper- and palladium-mediated aminations of aryl halides and triflates are now well-established,[1] and examples of mesylate[2] and tosylate[3] aminations have been reported. Most recent efforts have focused on the amination of classically “inert” phenolic derivatives (i.e., arylmethyl ethers[4] and aryl pivalate esters[5]), which could potentially be used in multistep synthesis.[6, 7] With the aim of assembling polysubstituted aryl amines, motifs commonly encountered in drug scaffolds, naturally occurring small molecules, pesticides, ligands for catalysis, and materials chemistry, we sought to uncover a versatile class of phenol-derived substrates that could undergo transition metal-catalyzed amination.
Estimating the trace-free Ricci tensor in Ricci flow

An important and natural question in the analysis of Ricci flow behavior in all dimensions n ≥ 4 is this: What are the weakest conditions that guarantee that a solution remains smooth? In other words, what are the weakest conditions that provide control of the norm of the full Riemann curvature tensor? In this short paper, we show that the trace-free Ricci tensor is controlled in a precise fashion by the other components of the irreducible decomposition of the curvature tensor, for all compact solutions in all dimensions n ≥ 3, without any hypotheses on the initial data.
On selection of reference temperature of heat transfer coefficient for complicated flows

Convective heat transfer coefficient is closely related with flow and thermal conditions. To define heat transfer coefficient, a reference temperature needs to be properly selected, which can be the fluid bulk mean temperature for internal flows or the temperature at the far field for external flows. For complicated flows, the adiabatic wall temperature is commonly adopted as the reference temperature, while other options can also be applied. This paper analyzed some of the potential selections of the reference temperature for different flow settings, including film cooling, jet impingement with cross flows, and a mixing flow in a straight duct with or without internal heat source. It is observed that heat transfer coefficient changes dramatically with selection of reference temperatures. In case of constant wall temperature, using adiabatic wall temperature as reference temperature can result in negative heat transfer coefficient, which means the heat flux has a different direction with the defined driving temperature difference. To avoid the inconsistency due to the reference temperature, an innovative method is proposed to calculate the heat transfer coefficient of complicated flows.
Does the availability of parental health insurance affect the college enrollment decision of young Americans

Abstract The present study examines whether the college enrollment decision of young individuals (student full-time, student part-time, and non-student) depends on health insurance coverage via a parent's family health plan. Our findings indicate that the availability of parental health insurance can have significant effects on the probability that a young individual enrolls as a full-time student. A young individual who has access to health insurance via a parent can be up to 22% more likely to enroll as a full-time student than an individual without parental health insurance. After controlling for unobserved heterogeneity this probability drops to 5.5% but is still highly significant. We also find that the marginal effect of the availability of parental health insurance has a larger effect on older students between ages 21 and 23. We provide a brief discussion about possible implications of the Affordable Care Act of 2010 in this context.
High-speed propulsion of flexible nanowire motors: Theory and experiments

Micro/nano-scale propulsion has attracted considerable recent attention due to its promise for biomedical applications such as targeted drug delivery. In this paper, we report on a new experimental design and theoretical modelling of high-speed fuel-free magnetically-driven propellers which exploit the flexibility of nanowires for propulsion. These readily prepared nanomotors display both high dimensional propulsion velocities (up to ≈ 21 μm s−1) and dimensionless speeds (in body lengths per revolution) when compared with natural microorganisms and other artificial propellers. Their propulsion characteristics are studied theoretically using an elastohydrodynamic model which takes into account the elasticity of the nanowire and its hydrodynamic interaction with the fluid medium. The critical role of flexibility in this mode of propulsion is illustrated by simple physical arguments, and is quantitatively investigated with the help of an asymptotic analysis for small-amplitude swimming. The theoretical predictions are then compared with experimental measurements and we obtain good agreement. Finally, we demonstrate the operation of these nanomotors in a real biological environment (human serum), emphasizing the robustness of their propulsion performance and their promise for biomedical applications.
Teacher Quality in Educational Production: Tracking, Decay, and Student Achievement

Growing concerns over the inadequate achievement of U.S. students have led to proposals to reward good teachers and penalize (or fire) bad ones . The leading method for assessing teacher quality is “value added” modeling (VAM), which decomposes students’ test scores into components attributed to student heterogeneity and to teacher quality. Implicit in the VAM approach are strong assumptions about the nature of the educational production function and the assignment of students to classrooms. In this paper, I develop falsification tests for three widely used VAM specifications , based on the idea that future teachers cannot influence students’ past achievement. In da ta from North Carolina, each of the VAMs’ exclusion restrictions are dramatically viola ted. In particular, these models indicate large “effects” of 5th grade teachers on 4th grade t est score gains. I also find that conventional measures of individual teachers’ value added fade out very quickly and are at best weakly related to long-run effects. I discuss implic ations for the use of VAMs as personnel tools.
Providing Services to Children with Autism (Ages 0 to 2 Years) and Their Families

Editor's Note: The current issue of Focus on Autistic Behavior features a reprint of Barry Prizant and Amy Wetherby's article, “Providing Services to Children with Autism (Ages 0 to 2 Years) and Their Families.” The article originally appeared in Topics in Language Disorders (1988, Vol. 9, No. I, pp. 1-23). Periodically the editorial staff will recommend reprinting classic articles (i.e., those that have withstood the test of time or have had significant impact for a period of time) as well as previously published works that appear to have particular merit. Prizant and Wetherby provide a unique look at issues, assessment methods, and intervention procedures for very young children and youths with autism. They describe not only difficulties encountered by professionals who work with young autistic children and youths, but also utilitarian assessment and intervention methods and suggestions. Special emphasis is given to communication and language development, areas of particular concern for both families an...
Noncommutativity and discrete physics

This paper is an introduction to discrete physics based on a non-commutative calculus of finite differences. This gives a context for the Feynman-Dyson derivation of non-commutative electromagnetism, and for generalizations of this result. The paper discusses these ideas and their relations with quantum groups and topological quantum field theory. © 1998 Elsevier Science B.V. All rights reserved.
Cosmic-ray electron signatures of dark matter

There is evidence for an excess in cosmic-ray electrons at about 500 GeV energy, that may be related to dark-matter annihilation. I have calculated the expected electron contributions from a pulsar and from Kaluza-Klein dark matter, based on a realistic treatment of the electron propagation in the Galaxy. Pulsars younger than about 10{sup 5} years naturally cause a narrow peak at a few hundred GeV in the locally observed electron spectrum, similar to that observed. On the other hand, if electron production by dark matter is predominantly occurring in high-mass clumps (> or approx. 10{sup 3}M{sub {center_dot}}), the sharp cutoff in the contribution from Kaluza-Klein particles is sometimes more pronounced, but often smoothed out and indistinguishable from a pulsar source, and therefore the spectral shape of the electron excess is insufficient to discriminate a dark-matter origin from more conventional astrophysical explanations.
Hybrid keyword search auctions

Search auctions have become a dominant source of revenue generation on the Internet. Such auctions have typically used per-click bidding and pricing. We propose the use of hybrid auctions where an advertiser can make a per-impression as well as a per-click bid, and the auctioneer then chooses one of the two as the pricing mechanism. We assume that the advertiser and the auctioneer both have separate beliefs (called priors) on the click-probability of an advertisement. We first prove that the hybrid auction is truthful, assuming that the advertisers are risk-neutral. We then show that this auction is superior to the existing per-click auction in multiple ways: We show that risk-seeking advertisers will choose only a per-impression bid whereas risk-averse advertisers will choose only a per-click bid, and argue that both kind of advertisers arise naturally. Hence, the ability to bid in a hybrid fashion is important to account for the risk characteristics of the advertisers. For obscure keywords, the auctioneer is unlikely to have a very sharp prior on the click-probabilities. In such situations, we show that having the extra information from the advertisers in the form of a per-impression bid can result in significantly higher revenue. An advertiser who believes that its click-probability is much higher than the auctioneer's estimate can use per-impression bids to correct the auctioneer's prior without incurring any extra cost. The hybrid auction can allow the advertiser and auctioneer to implement complex dynamic programming strategies to deal with the uncertainty in the click-probability using the same basic auction. The per-click and per-impression bidding schemes can only be used to implement two extreme cases of these strategies. As Internet commerce matures, we need more sophisticated pricing models to exploit all the information held by each of the participants. We believe that hybrid auctions could be an important step in this direction. The hybrid auction easily extends to multiple slots, and is also applicable to scenarios where the hybrid bidding is per-impression and per-action (i.e. CPM and CPA), or per-click and per-action (i.e. CPC and CPA).
Choosing to Love

This essay proposes a pedagogical ethic of love based on the four brahma-viharas -- also called the divine abodes-- of Theravada Buddhism. Witnessing, Kelly Oliver’s theory of mutual subjectivity, finds practical expression in the brahma-viharas, a comprehensive way to train the mind and heart to sustain an ethic of love in all of our relationships. Together, witnessing and the brahma-viharas offer an approach whereby we may choose to love students and to cultivate more open, responsive and egalitarian relations with them, in spite of academic asymmetries of power. In perplexing or vexing interactions with students, I draw strength from three of the four divine abodes: metta (lovingkindness), karuna (compassion), and upekkha (equanimity). Consistently applying the contemplative practices associated with these states begins to disentangle the threads of complicated social relations.
Global Analysis of Agricultural Trade Liberalization: Assessing Model Validity

This paper presents a validation experiment of a global CGE trade model widely used for analysis of trade liberalization. We focus on the ability of the model to reproduce price volatility in wheat markets. The literature on model validation is reviewed with an eye towards designing an appropriate methodology for validating large scale CGE models. The validation experiment results indicate that in its current form, the GTAPAGR model is incapable of reproducing wheat market price volatility and that trade and poverty analysis taking these prices as inputs might be wrongly influenced. We conclude that model validation is tractable and an important component of analysis, as it points to areas to consider for refining analysis. In the specific case presented here, it seems that the Armington structure and trade elasticities are influential in whether the model over our under predicts price volatility for a specific region based on its net trade position for wheat.
Ground delay program planning under uncertainty in airport capacity

This paper presents an algorithm that can assign flight departure delays under probabilistic airport capacity. The algorithm dynamically adapts to weather forecasts by revising, if necessary, departure delays. The information required by the algorithm is considerably less than that required by existing stochastic dynamic optimization models. The proposed algorithm leverages state-of-the-art optimization techniques that have appeared in recent literature. It is a viable approach for planning ground delay programs at airports where probabilistic information on airport capacity are available. As a case study, the algorithm is applied to assigning departure delays to flights scheduled to arrive at San Francisco International Airport in the presence of uncertainty in the fog clearance time. The cumulative distribution function of fog clearance time was estimated from historical observations on 387 days in 2004-2007. When probabilistic weather forecasts were used to update the probabilities of fog clearance times, the expected delays obtained from the algorithm were reduced by approximately 7% compared to delays when the forecasts where not utilized. Experimental results also indicate that if the proposed algorithm is applied to assign ground delays to flights inbound at San Francisco International airport, overall delays could be reduced up to 20% compared to current level.
Computably Categorical Fields via Fermat’s Last Theorem

We construct a computable, computably categorical field of infinite transcendence degree over the rational numbers, using the Fermat polynomials and assorted results from algebraic geometry. We also show that this field has an intrinsically computable (infinite) transcendence basis.
RECONSTRUCTING DECONSTRUCTION: HIGH-VELOCITY CLOUD DISTANCE THROUGH DISRUPTION MORPHOLOGY

We present Arecibo L-band Feed Array 21 cm observations of a subcomplex of HVCs at the tip of the anticenter complex. These observations show morphological details that point to interaction with the ambient halo medium and differential drag within the cloud subcomplex. We develop a new technique for measuring cloud distances, which relies on these observed morphological and kinematic characteristics, and show that it is consistent with Hα distances. These results are consistent with distances to HVCs and halo densities derived from models in which HVCs are formed from cooling halo gas.
The Almost Sure Invariance Principle for Beta-Mixing Measures

The theorem of Shannon–McMillan–Breiman states that for every generating partition on an ergodic system of finite entropy the exponential decay rate of the measure of cylinder sets equals the metric entropy almost everywhere. In addition the measure of \(n\)-cylinders is in various settings known to be lognormally distributed in the limit. In this paper the logarithm of the measure of \(n\)-cylinder, the information function, satisfies the almost sure invariance principle in the case in which the measure is \(\beta \)-mixing. We get a similar result for the recurrence time. Previous results are due to Philipp and Stout who deduced the ASIP when the measure is strong mixing and satisfies an \(\fancyscript{L}^1\)-type Gibbs condition. We also prove the ASIP for the recurrence time.
Analysis and design of RNA sequencing experiments for identifying isoform regulation

Through alternative splicing, most human genes express multiple isoforms that often differ in function. To infer isoform regulation from high-throughput sequencing of cDNA fragments (RNA-seq), we developed the mixture-of-isoforms (MISO) model, a statistical model that estimates expression of alternatively spliced exons and isoforms and assesses confidence in these estimates. Incorporation of mRNA fragment length distribution in paired-end RNA-seq greatly improved estimation of alternative-splicing levels. MISO also detects differentially regulated exons or isoforms. Application of MISO implicated the RNA splicing factor hnRNP H1 in the regulation of alternative cleavage and polyadenylation, a role that was supported by UV cross-linking-immunoprecipitation sequencing (CLIP-seq) analysis in human cells. Our results provide a probabilistic framework for RNA-seq analysis, give functional insights into pre-mRNA processing and yield guidelines for the optimal design of RNA-seq experiments for studies of gene and isoform expression.
Cross-Layer Scheduling for Cooperative Multi-Hop Cognitive Radio Networks

In this paper, a cross-layer optimal scheduling algorithm for cooperative multi-hop Cognitive Radio Networks (CRNs) is presented, where secondary users (SUs) assist primary users' (PUs') multi-hop transmissions and in return gain an immediate time-share of the channel proportional to their assistance. While providing deterministic upper-bounds for PU queue backlogs, the proposed algorithm approaches the optimal PU throughput arbitrarily close, with a tradeoff in the average delay upper-bounds of flows. The analysis is further extended to a model with a more general "long-term reward mechanism", where a time-averaged share of the channel is guaranteed for SUs. The proposed algorithm provides order-optimal delay for the primary traffic. Distributed implementation issues have also been investigated. The properties of the proposed algorithm have also been illustrated through simulation studies.
SEARCH, LIMITED PARTICIPATION, AND MONETARY POLICY*

A model is developed that employs recent developments in the literature on search models of money to capture the distributional effects of monetary policy in a tractable way. Deterministic and stochastic versions of the model are studied. Money is not neutral, and these nonneutralities persist, whether or not the change in the money supply is anticipated or unanticipated. At the optimum, monetary policy is geared to correcting distortions in the search sector of the economy, while correcting for the persistent effects of past monetary policy actions. There is no consensus among macroeconomists concerning the role of monetary policy in the short run. However, an influential idea is that limited participation in financial markets is an important mechanism behind the short-run macroeconomic effects of central bank actions. That is, there is a component of economic activity that is centralized and interconnected. This economic activity involves financial transactions among banks and other financial intermediaries and the agents who hold the assets and liabilities of these financial intermediaries. When the central bank injects outside money into the economy, or withdraws it, the economic agents who are immediately affected by the monetary injection or withdrawal are the participants in these centralized transactions. Other economic agents, who are engaged in more decentralized and less interconnected transactions, will not be affected directly by the first-round effects of central bank actions. Thus, there will be a distributional effect of monetary injections and withdrawals, as first captured in heterogeneous agent models by Grossman and Weiss (1983) and Rotemberg (1984). This distributional effect will matter in interesting ways for the price level, nominal interest rates, aggregate output, foreign exchange rates, and the distribution of consumption across the population. The Grossman‐Weiss and Rotemberg models are not analytically tractable, because of the difficulty in tracking the distribution of wealth over time. However, Lucas (1990), Fuerst (1992), and Alvarez and Atkeson (1997), among others,
Self-report pain and symptom measures for primary dysmenorrhoea: A critical review

Primary dysmenorrhoea (PD) is highly prevalent among women of reproductive age and it can have significant short- and long-term consequences for both women and society as a whole. Validated symptom measures are fundamental for researchers to understand women's symptom experience of PD and to test symptom interventions. The objective of this paper was to critically review the content and psychometric properties of self-report tools to measure symptoms of PD. Databases including PubMed, PsychoINFO, Cumulative Index of Nursing and Allied Health Literature, and Health and Psychosocial Instruments were searched for self-report symptom measures that had been used among women with either PD or perimenstrual symptoms. A total of 15 measures met inclusion criteria and were included in the final analysis. The measures were categorized into generic pain measures, dysmenorrhoea-specific measures, and tools designed to measure perimenstrual symptoms. These measures had varying degrees of comprehensiveness of symptoms being measured, relevance to PD, multidimensionality and psychometric soundness. No single measure was found to be optimal for use, but some dysmenorrhoea-specific measures could be recommended if revised and further tested. Key issues in symptom measurement for PD are discussed. Future research needs to strengthen dysmenorrhoea-specific symptom measures by including a comprehensive list of symptoms based on the pathogenesis of PD, exploring relevant symptom dimensions beyond symptom severity (e.g., frequency, duration, symptom distress), and testing psychometric properties of the adapted tools using sound methodology and diverse samples.
Bandgap engineering of strained monolayer and bilayer MoS2.

We report the influence of uniaxial tensile mechanical strain in the range 0–2.2% on the phonon spectra and bandstructures of monolayer and bilayer molybdenum disulfide (MoS2) two-dimensional crystals. First, we employ Raman spectroscopy to observe phonon softening with increased strain, breaking the degeneracy in the E′ Raman mode of MoS2, and extract a Gruneisen parameter of ∼1.06. Second, using photoluminescence spectroscopy we measure a decrease in the optical band gap of MoS2 that is approximately linear with strain, ∼45 meV/% strain for monolayer MoS2 and ∼120 meV/% strain for bilayer MoS2. Third, we observe a pronounced strain-induced decrease in the photoluminescence intensity of monolayer MoS2 that is indicative of the direct-to-indirect transition of the character of the optical band gap of this material at applied strain of ∼1%. These observations constitute a demonstration of strain engineering the band structure in the emergent class of two-dimensional crystals, transition-metal dichalcogenides.
Improved stability analysis and gain-scheduled controller synthesis for parameter-dependent systems

We present new algorithms for robust stability analysis and gain-scheduled controller synthesis for linear systems affected by time-varying parametric uncertainties. These new techniques can also be applied to parameter-dependent nonlinear systems with real-rational nonlinearities. Sufficient conditions for robust stability, as well as conditions for the existence of a robustly stabilizing gain-scheduled controller, are given in terms of a finite number of linear matrix inequalities (LMIs); explicit formulas for constructing robustly stabilizing gain-scheduled controllers are given in terms of the feasible set of these LMIs. The improvement offered by our approach over existing methods for stability analysis and gain-scheduled controller synthesis for parameter-dependent linear systems are analyzed in theory. Numerical examples demonstrate that our approach can offer significant improvement in practice.
Impact of dry eye on reading in a population based sample of the elderly: the Salisbury Eye Evaluation

Background/aims People with dry eye often complain of difficulty reading, but this perceived deficit has not been appropriately quantified. The purpose of this study is to determine if dry eye is associated with measurable reading deficits. Methods A cross-sectional study of 1981 participants in the Salisbury Eye Evaluation, a population-based study of the elderly. Dry eye symptoms were identified by questionnaire and clinically significant dry eye was defined as the presence of dry eye symptoms and positive Schirmer testing or ocular surface staining in either eye. Spoken reading speed was measured using short text passages. Subjects self-reported if they did not read or had difficulty reading newsprint. Results 13.8% of subjects (274/1981) had dry eye symptoms and 3.1% (62/1981) had clinically significant dry eye. There was no difference in reading speed between subjects with dry eye symptoms or clinically significant dry eye and their controls (p=0.99 and 0.78, respectively) in multivariable models. Compared with asymptomatic subjects, however, subjects with dry eye symptoms were more likely to report reading difficulty (OR=1.7, 95% CI 1.3 to 2.4, p Conclusions Dry eye did not significantly affect reading speed but was associated with self-reported reading difficulty and avoidance of newspaper reading in this elderly population-based sample.
Resolving trade disputes arising from trends in food safety regulation: the role of the multilateral governance framework

New food regulations may impede international trade, but multilateral mechanisms can resolve trade conflicts when they do arise. Food safety regulation in industrialized countries during the 1990s increasingly uses risk analysis in a farm-to-table approach, promotes the Hazard Analysis and Critical Control Point (HACCP) system, and increases the stringency of standards or creates new regulations for hazards. The 1995 Agreement on the Application of Sanitary and Phytosanitary Measures (SPS Agreement), negotiated by World Trade Organization (WTO) members, establishes a framework to reduce their trade distorting aspects. Three of the principles under the SPS Agreement – science-based risk assessment, equivalence, and harmonization – directly address aspects of food safety regulation that create the potential for trade disputes. In many cases, the science requirements of the Agreement have led to the elimination of unnecessary regulatory barriers to trade. However, some high profile cases remain unresolved because of gaps in convergence around risk management principles that were not spelled out in the Agreement in deference to national sovereignty. The evidence also indicates that there has been limited progress in reducing regulatory transactions costs to trade in food through equivalence or harmonization.
Primary Seat Belt Laws and Offsetting Behavior: Empirical Evidence from Individual Accident Data ∗

According to the offsetting effect theory, since drivers wearing seat belts feel more secure, they tend to drive less carefully and may cause more accidents, including those involving pedestrians. Most previous studies have used only state-level accident data, which cannot control for individual characteristics of drivers, vehicles, and the environmental factors surrounding the accidents. This paper uses individual-level accident data to analyze how drivers respond to the laws exploiting changes in the seat belt laws in a number of US states in the last decade. I find that the laws do not cause less careful behavior by drivers. In fact, they drive more carefully when more stringent seat belt laws are in effect, and this leads to less involvement of pedestrians in accidents. These results show that the offsetting effects do not exist when all accidents, including fatal accidents, are considered.
Colliders and cosmology

Dark matter in variations of constrained minimal supersymmetric standard models will be discussed. Particular attention will be given to the comparison between accelerator and direct detection constraints.
Effective Variants of the Max-Sum Algorithm for Radar Coordination and Scheduling

Solving a coordination problem in a decentralized environment requires a large amount of resources and thus exploiting the innate system structure and external information as much as possible is necessary for such a problem to be solved in a computationally effective manner. This work proposes new techniques for saving communication and computational resources when solving distributed constraint optimization problems using the Max-Sum algorithm in an environment where system hardware resources are clustered. These techniques facilitate effective problem solving through the use of a pre-computed policy and two phase propagation on Max-Sum algorithm, one inside the clustered resources and one among clustered resources. This approach shows equivalent quality to the standard Max-Sum algorithm while reducing communication requirements on average by50\% and computation resources by 5 to 30\% depending on the specific problem instance. These experiments were performed in a realistic setting involving the scheduling of a network of as many as 192 radars in 48 clusters.
An empirical investigation of Wal-Mart's expansion into food retailing

After revolutionizing the concept of mass merchandising with its Discount Stores, Wal-Mart has entered food retailing with its Supercenters, and has become the largest food retailer in the United States. Despite its relevance, little empirical research has focused on explaining the company's entry and expansion into food retailing. Wal-Mart's expansion into food retailing through its store conversion strategy is analyzed using an industrial organization entry framework. The results show that Wal-Mart's store conversion strategy has targeted largely populated areas with low population density, a high percentage of population receiving food stamps, and where the presence of incumbents is modest. The results also provide evidence that as the company moves toward saturation of local markets and increases store conversion rates, it may be forced to reconsider some of its strategic decisions based on the exploitation of economies of density and store conversion. © 2010 Wiley Periodicals, Inc.
Aerobic Alcohol Oxidation Coupled to Palladium-Catalyzed Alkene Hydroarylation with Boronic Esters†

The Suzuki reaction, which couples an organohalide and an organoboron compound,[1] is an attractive cross-coupling reaction for use in the synthesis of natural products[2] and pharmaceuticals.[3] This utility is mainly because of the excellent functional group compatibility, ease of preparation of boronic acid derivatives, and the low toxicity of the boron byproducts.[2] The mechanistic details have been widely investigated and the reaction is thought to proceed through oxidative addition of the organohalide (R–X) to Pd0 to form R–PdII–X and then transmetalation of the organoborane (R1– B(OR)2).[1] The resulting R–PdII–R1 intermediate undergoes reductive elimination to form the product. An exogenous base is required to activate the boronic acid derivative for transmetalation, which is proposed to occur through a four-centered transition state (intermediate C, Scheme 1a).[4]
Measurement of the ultrafast temporal response of a plasmonic antenna

nd that the far-eld dispersion of light reected from the plasmonic antenna is less than that of a 1 :2mm thick glass slide. Assuming a simple oscillating dipole model this implies that the near-eld of the antenna may be used as an electron switch that responds faster than 20fs. Alternatively, ultrafast electron diraction may be used to investigate the near-eld dynamics of the plasmonic antenna.
Exploration and Exploitation in Organizational Learning

This paper considers the relation between the exploration of new possibilities and the exploitation of old certainties in organizational learning. It examines some complications in allocating resources between the two, particularly those introduced by the distribution of costs and benefits across time and space, and the effects of ecological interaction. Two general situations involving the development and use of knowledge in organizations are modeled. The first is the case of mutual learning between members of an organization and an organizational code. The second is the case of learning and competitive advantage in competition for primacy. The paper develops an argument that adaptive processes, by refining exploitation more rapidly than exploration, are likely to become effective in the short run but self-destructive in the long run. The possibility that certain common organizational practices ameliorate that tendency is assessed.
Organizational Complexity and Succession Planning

This study uses a large sample of firms to examine how human capital considerations affect the process of CEO succession. Costs and benefits of succession planning are affected by a firm's level of operational complexity and human capital requirements; firms that are more complex incur greater costs to transferring firm-specific knowledge and expertise to an outsider, and should be more likely to groom an internal candidate for the CEO position. Consistent with this, I find that a firm's propensity to groom an internal candidate for the CEO position is related to firm size, degree of diversification, and industry structure. My results also suggest that succession planning is associated with a higher probability of inside succession and voluntary succession and a lower probability of forced succession. I also provide evidence that horizon problems are mitigated to some extent by having a succession plan.
Implications of Supersymmetric Grand Unification

Unification of the interactions of the Standard Model is possible in its simplest supersymmetric extension. The implications of the λt fixed-point solution on the top mass and on Higgs phenomenology is discussed. Expected correlations between the masses of various supersymmetric particles are detailed.
Potential hazards from neutrino radiation at muon colliders

High energy muon colliders, such as the TeV-scale conceptual designs now being considered, are found to produce enough high energy neutrinos to constitute a potentially serious off-site radiation hazard in the neighbourhood of the accelerator site. A general characterization of this radiation hazard is given, followed by an order-of-magnitude calculation for the off-site annual radiation dose and a discussion of accelerator design and site selection strategies to minimize the radiation hazard.
Power-delay analysis of consensus algorithms on wireless networks with interference

We study the convergence of the average consensus algorithm in wireless networks in the presence of interference. For regular lattices with periodic boundary conditions, we characterise the convergence properties of an optimal Time Division Multiple Access (TDMA) protocol that maximises the speed of convergence on these networks. We provide analytical upper and lower bounds for the convergence rate for these networks. Our results show that in an interference-limited scenario, the fastest converging interconnection topology for the consensus algorithm crucially depends on the geometry of node placement. In particular, we prove that asymptotically in the number of nodes, increasing the transmit power to allow long-range interconnections improves the convergence rate in one-dimensional tori, while it has the opposite effect in higher dimensions.
Deracemization of Quaternary Stereocenters by Pd‐Catalyzed Enantioconvergent Decarboxylative Allylation of Racemic β‐Ketoesters

Stereochemical alchemy! Racemic allyl β-ketoesters allow the regiocontrolled formation of enolates, where the same catalyst is intimately involved in both the stereoablative (C-C bond-breaking) and stereoselective (C-C bond-forming) steps. This mechanistic and practical insight led to the formation of multiple quaternary carbon stereocenters in a single cascade reaction (see scheme).
Chromosome-Biased Binding and Gene Regulation by the Caenorhabditis elegans DRM Complex

DRM is a conserved transcription factor complex that includes E2F/DP and pRB family proteins and plays important roles in development and cancer. Here we describe new aspects of DRM binding and function revealed through genome-wide analyses of the Caenorhabditis elegans DRM subunit LIN-54. We show that LIN-54 DNA-binding activity recruits DRM to promoters enriched for adjacent putative E2F/DP and LIN-54 binding sites, suggesting that these two DNA–binding moieties together direct DRM to its target genes. Chromatin immunoprecipitation and gene expression profiling reveals conserved roles for DRM in regulating genes involved in cell division, development, and reproduction. We find that LIN-54 promotes expression of reproduction genes in the germline, but prevents ectopic activation of germline-specific genes in embryonic soma. Strikingly, C. elegans DRM does not act uniformly throughout the genome: the DRM recruitment motif, DRM binding, and DRM-regulated embryonic genes are all under-represented on the X chromosome. However, germline genes down-regulated in lin-54 mutants are over-represented on the X chromosome. We discuss models for how loss of autosome-bound DRM may enhance germline X chromosome silencing. We propose that autosome-enriched binding of DRM arose in C. elegans as a consequence of germline X chromosome silencing and the evolutionary redistribution of germline-expressed and essential target genes to autosomes. Sex chromosome gene regulation may thus have profound evolutionary effects on genome organization and transcriptional regulatory networks.
Signal coding for low power: fundamental limits and practical realizations

Transitions on high capacitance buses result in considerable system power dissipation. Therefore, various coding schemes have been proposed in the literature to encode the input signal in order to reduce the number of transitions. In this paper, we present: 1) fundamental bounds on the activity-reduction capability of any encoding scheme for a given source and 2) practical novel encoding schemes that approach these bounds. The fundamental bounds in 1) are obtained via an information theoretic approach, where a signal x(n) with entropy rate /spl Hscr/ is coded with R bits per sample on average. The encoding schemes in 2) are developed via a communication-theoretic approach, whereby a data source is passed through a decorrelating function followed by a variant of entropy coding function which reduces the transition activity. Simulation results with an encoding scheme for data busses indicate an average reduction in transition activity of 36%.
Sources of Corruption in Authoritarian Regimes

Objectives. We seek to investigate the determinants of corruption in authoritarian polities. We hypothesize that corruption in nondemocratic settings will be greater where the ruling group is personalistic rather than a political party or a military clique and that it will be greater where rulers expect to remain in power longer. We construct a new operationalization of the selectorate theory advanced by Bueno de Mesquita et al. Methods. We use cross-sectional statistical analysis (OLS) to examine a sample of 40-odd authoritarian regimes as of 2000. Results. Our results indicate that personalistic and personalistic-hybrid regimes are more prone to corruption than single-party and military regimes and also that rulers who expect to remain in power for longer are less corrupt. Corroborating previous studies, we document that the availability of natural resources and higher levels of institutionalized autocracy are associated with greater corruption and that wealthier countries experience less corruption. Our results are consistent with previous studies, including that of Bueno de Mesquita et al., but because of our reconstruction of selectorate theory in terms of real-world regime types, they are more easily interpretable. Conclusions. Our study sheds light on why African countries are so notoriously corrupt. The personalistic authoritarian regimes that have arisen there in the postcolonial period appear especially prone to corruption, whereas military and single-party dictatorships are less corrupt.
Dynamics of 3D SUSY gauge theories with antisymmetric matter

We investigate the IR dynamics ofN = 2 SUSY gauge theories in 3D with antisymmetric matter. The presence of the antisymmetric elds leads to further splitting of the Coulomb branch. Counting zero modes in the instanton background suggests that more than a single direction along the Coulomb branch may remain unlifted. We examine the case of SU(4) with one or two antisymmetric elds and various avors in detail. Using the results for the corresponding 4D theories, we nd the IR dynamics of the 3D cases via compactication and a real mass deformation. We nd that for the s-conning case with two antisymmetric elds, a second unlifted Coulomb branch direction indeed appears in the low-energy dynamics. We present several non-trivial consistency checks to establish the validity of these results. We also comment on the expected structure of general s-conning theories in 3D, which might involve several unlifted Coulomb branch directions.
Forced Motion of Cylindrical Shells — A Comparison of Shell Theory with Elasticity Theory

Die dynamische Reaktion einer frei gelagerten kreiszylindrischen Schale wird im Rahmen der dreidimensionalen Elastizitatstheorie behandelt. Fur eine spezielle Lastverteilung und Schalengeometrie wird die so gewonnene Losung mit derjenigen, die man im Rahmen der Fluggeschen und der „verbesserten” Schalentheorie erhalt, numerische verglichen. Es zeigt sich, das — gemessen an der elastizitatstheoretischen Losung — die „verbesserte” Theorie hinsichtlich der Voraussage des Reaktionsverhaltens der Schale uber Zeiten, die die Spannungs- und Verschiebungs-maxima enthalten, bessere Ergebnisse liefert als die Fluggesche Theorie und das auserdem Vorsicht am Platze ist, wenn eine der Schalentheorien auf das anfangliche Reaktionsverhalten angewendet wird. The dynamic response of a freely supported circular cylindrical shell is treated within the framework of the three dimensional theory of elasticity. A numerical comparison of this solution with corresponding solutions within the framework of the Flugge and “improved” shell theories is presented for a specific load distribution and shell geometry. When compared to the elasticity theory solution, it is shown that improved theory is better than Flugge theory in predicting the response over times which contain the maximum stresses and displacements. The results also show that caution must be used when applying either of the shell theories to the initial response.
Analysis of Power-Cycling Capability of IGBT Modules in a Conventional Matrix Converter

This paper analyzes the power-cycling capability of insulated-gate bipolar transistor (IGBT) modules in a conventional matrix converter used as a motor drive. The analysis is made under various conditions for this topology, including low-speed-operation capability, high-speed thermal- and power-cycling capabilities, etc. It was found that the power-cycling mean time to failure of IGBT in a matrix converter is low when the input and output frequencies are close to each other or when the output frequency of the converter is low. As a result, the chip size of the conventional matrix converter may be larger than the other candidates. In the end of this paper, some guidance for designing a matrix converter for long-term reliabilities is also discussed.
The density of mid-sized Kuiper belt object 2002 UX25 and the formation of the dwarf planets

The formation of the largest objects in the Kuiper belt, with measured densities of ~1.5 g cm^(–3) and higher, from the coagulation of small bodies, with measured densities below 1 g cm^(–3), is difficult to explain without invoking significant porosity in the smallest objects. If such porosity does occur, measured densities should begin to increase at the size at which significant porosity is no longer supported. Among the asteroids, this transition occurs for diameters larger than ~350 km. In the Kuiper belt, no density measurements have been made between ~350 km and ~850 km, the diameter range where porosities might first begin to drop. Objects in this range could provide key tests of the rock fraction of small Kuiper belt objects (KBOs). Here we report the orbital characterization, mass, and density determination of the 2002 UX25 system in the Kuiper belt. For this object, with a diameter of ~650 km, we find a density of 0.82 ± 0.11 g cm^(–3), making it the largest solid known object in the solar system with a measured density below that of pure water ice. We argue that the porosity of this object is unlikely to be above ~20%, suggesting a low rock fraction. If the currently measured densities of KBOs are a fair representation of the sample as a whole, creating ~1000 km and larger KBOs with rock mass fractions of 70% and higher from coagulation of small objects with rock fractions as low as those inferred from 2002 UX25 is difficult.