cssi/SciSciGPT-SciSciNet huggingface dataset:
The Aggregate Effect of School Choice: Evidence from a Two-Stage Experiment in India

We present experimental evidence on the impact of a school choice program in the Indian state of Andhra Pradesh that provided students with a voucher to finance attending a private school of their choice. The study design featured a unique two-stage lottery-based allocation of vouchers that created both student-level and market-level experiments, which allows us to study the individual and the aggregate effects of school choice (including spillovers). After two and four years of the program, we find no difference between test scores of lottery winners and losers on Telugu (native language), math, English, and science/social studies, suggesting that the large cross-sectional differences in test scores across public and private schools mostly reflect omitted variables. However, private schools also teach Hindi, which is not taught by the public schools, and lottery winners have much higher test scores in Hindi. Furthermore, the mean cost per student in the private schools in our sample was less than a third of the cost in public schools. Thus, private schools in this setting deliver slightly better test score gains than their public counterparts (better on Hindi and same in other subjects), and do so at a substantially lower cost per student. Finally, we find no evidence of spillovers on public school students who do not apply for the voucher, or on private school students, suggesting that the positive effects on voucher winners did not come at the expense of other students. JEL Codes: C93, H44, H52, I21, O15.
Graphical description of the action of Clifford operators on stabilizer states

We introduce a graphical representation of stabilizer states and translate the action of Clifford operators on stabilizer states into graph operations on the corresponding stabilizer-state graphs. Our stabilizer graphs are constructed of solid and hollow nodes, with (undirected) edges between nodes and with loops and signs attached to individual nodes. We find that local Clifford transformations are completely described in terms of local complementation on nodes and along edges, loop complementation, and change of node type or sign. Additionally, we show that a small set of equivalence rules generates all graphs corresponding to a given stabilizer state; we do this by constructing an efficient procedure for testing the equality of any two stabilizer graphs.
Magnetic field generation by the stationary accretion shock instability

By adding a weak magnetic field to a spherically symmetric fluid configuration that caricatures a stalled shock in the post-bounce supernova environment, we explore the capacity of the stationary accretion shock instability (SASI) to generate magnetic fields. The SASI develops upon perturbation of the initial condition, and the ensuing flow generates—in the absence of rotation—dynamically significant magnetic fields (~ 1015 G) on a time scale that is relevant for the explosion mechanism of core collapse supernovae. We describe our model, present some recent results, and discuss their potential relevance for supernova models.
Indoloquinones from azomethine ylides via the 4-oxazoline route

Abstract Internal trapping of the azomethine ylide 12 affords the bicyclic pyrrole 14 after deprotection. Further conversion of 14 into indoloquinone 17 is described.
Gamma ray lines from dark matter annihilation

Abstract If direct annihilation of dark matter particles into a pair of photons occurs in the galactic halo, a narrow γ-ray line can be discovered at future γ-ray detectors sensitive to the GeV region. The signals predicted by different dark matter candidates are analyzed.
Relooking at services science and services innovation

In lots of countries, service economy has become the dominant economy. Modern services industries require talents skillful at multidiscipline subjects including IT services, business models, management skills, psychology, etc. There is the rise of services science, service-oriented computing, and services computing. The multidiscipline features bring new challenges for services science. In this paper, we go beyond the traditional view of services and propose a three-layer framework for services science and services innovation. The framework covers service needs, service competencies, and service resources. We believe that these are the common building blocks and foundations for modern services industries. We use Amazon as an example to show the relevant of the framework for analyzing patterns of services innovation. We also use this framework to derive a set of service curricula for training talents for modern services.
Asymmetric synthesis of α-hydroxy- phosphonamides, phosphonates and phosphonic acids

Abstract The addition of the anion of the bicyclic chiral phosphorous acid diamide 1a to aldehydes in THF solution gave α-hydroxy phosphonamides in good yield and good diastereoselectivity (54–93% de). The phosphonamides were hydrolyzed with aqueous HCl in dioxane to give α-hydroxy phosphonic acids. Methylation of the resulting phosphonic acids with diazomethane gave α-hydroxy dimethyl phosphonates without loss of stereochemical integrety.
Synthesis of 9-(2-Deoxy-β-D-ribofuranosyl)purine-2-thione

Abstract A synthesis of 9-(2-deoxy-β-D-ribofuranosyl)purine-2-thione was performed by desulfurization of 2′-deoxy-6-thioguanine to give 2-amino-9-(2-deoxy-β-D-ribofuranosyl)purine, diazotization with chloride replacement to give 2-chloro-9-(2-deoxy-β-D-ribofuranosyl)purine, and the replacement of chloride with sulfur using thiolacetic acid and deacetylation.
Activity-guided isolation of constituents of Cerbera manghas with antiproliferative and antiestrogenic activities.

Abstract Two new cardenolides, (−)-14-hydroxy-3β-(3- O -methyl-6-deoxy-α- l -rhamnosyl)-11α,12α-epoxy-(5β,14β,17βH)-card-20(22)-enolide ( 1 ), (−)-14-hydroxy-3β-(3- O -methyl-6-deoxy-α- l -glucopyranosyl)-11α,12α-epoxy-(5β,14β,17βH)-card-20(22)-enolide ( 2 ), and a known cardenolide, (−)-17β-neriifolin ( 3 ), were isolated from the roots of Cerbera manghas as antiproliferative and antiestrogenic principles when evaluated against a human colon cancer cell line (Col2) and the Ishikawa cell line, respectively. Two known lignans, (−)-olivil ( 4 ) and (−)-cycloolivil ( 5 ), were also isolated but were inactive in the assay systems used.
Distortion Minimization During Gas Quenching Process

Abstract During gas quenching, independent process parameters include the preheat temperature of the component and the temperature of the circulated gas. One of the most important dependent process parameters is the heat transfer coefficient between the component and the circulated gas. The heat transfer coefficient has significant influence on the quenching results, such as distortion, residual stresses, and hardness distribution. Large distortions after quenching will increase the cost due to the post-quenching processes, such as the grinding and hot rectification. The objective in this research is to minimize the distortion caused by quenching. In this paper, the surface of a component is divided into several regions, and different values of the heat transfer coefficient are imposed on each region. Constraints on the residual stresses and surface hardness distribution are imposed to improve the service properties. The heat transfer coefficients are ideal design variables to optimize the gas quenching process. The commercial finite element software, DEFORM-HT, is used to predict the material response during the quenching process. The response surface method is used to obtain the analytical models of the objective function and constraints in terms of the design variables. Once the closed-form response surface models are obtained, a commercially available design optimization tool, design optimization tool (DOT), is used to search for the optimum design point. This paper summarizes the methodology used to optimize the gas quenching process together with an application of a steel disk example.
Bayesian Modeling of Temporal Dependence in Large Sparse Contingency Tables

It is of interest in many applications to study trends over time in relationships among categorical variables, such as age group, ethnicity, religious affiliation, political party, and preference for particular policies. At each time point, a sample of individuals provides responses to a set of questions, with different individuals sampled at each time. In such settings, there tend to be an abundance of missing data and the variables being measured may change over time. At each time point, we obtained a large sparse contingency table, with the number of cells often much larger than the number of individuals being surveyed. To borrow information across time in modeling large sparse contingency tables, we propose a Bayesian autoregressive tensor factorization approach. The proposed model relies on a probabilistic Parafac factorization of the joint pmf characterizing the categorical data distribution at each time point, with autocorrelation included across times. We develop efficient computational methods th...
A verifiable protection system

This paper reports on the design and implementation of the UCLA Virtual Machine System, a multiuser operating system base that has been developed to provide ultra high reliability protection and security. Details are presented of the UCLA-VM system, a prototype of which now exists. Concepts which have influenced its structure are discussed, including program verification, security kernels, virtual machines, virtual memory, and the need for flexible information sharing facilities. A new mechanism, capability faulting, is developed in order to remove much of the virtual memory support from the security kernel. Flexible, reliable control of sharing is obtained by extensions to several of these concepts, especially through the use of levels of kernels.
A look at mesomerism in nitrobenzene

Abstract There is considerable evidence against the involvement of resonance structures I-III in describing the ground state properties of nitrobenzenes. It was found that RHF calculations, even with extended basis sets, do a poor job of reproducing important properties of nitrobenzene such as the geometry, rotational barrier, and dipole moment. Mulliken populations supplemented by a bond point characterization were found to be more consistent with a π-polarization effect. Consideration of experimental data showed that mesomeric resonance forms of the sort indicated m I-III were not important in describing many ground state properties. Thus the structural predictions of I-III are not observed. The rotational barrier for nitrobenzene is not very large, contrary to expectations from I-III. In addition, 3- and 4-fluorobenzene do not show rotational barriers that can be rationalized with mesomerism. The mesomeric contribution to the dipole moment has been shown to be small and possibly attributable to other factors. Finally, there is no thermochemical evidence of stabilization from mesomerism. The utility of any model lies m its capability to rationalize observed chemical behavior and properties and to make predictions. Mesomeric structures rationalize some data quite well. Dipole moments of mutually conjugated compounds, for example, and no new explanation of this phenomenon is offered here. Nevertheless, commonly used (actually overused) structures I-III, VII, and VIII and probably similar ones are quite misleading. Mesomerism is clearly not a dominating effect for determining many chemical properties. We suggest that structure V or VI represents a more accurate description of the charge distribution in nitrobenzene without being misleading.
An ultraminiature CMOS pressure sensor for a multiplexed cardiovascular catheter

A multiplexed ultraminiature pressure sensor designed for use in a cardiovascular catheter is described. The sensor operates from only two loads, which are shared by two sensors per catheter. The sensing chip is 350 mu m wide by 1.4 mm long by 100 mu m thick. CMOS readout circuitry at the sensing site converts applied pressure to a frequency variation in the supply current, which is detected at the end of the catheter by a microprocessor-controlled interface. The nominal pressure sensitivity is 2 kHz/fF about a zero-pressure output frequency of 2.7 MHz. This on-site circuitry contains two reference capacitors which allow external compensation for nonlinearity and temperature sensitivity and has an idle-state power dissipation of less than 50 mu W. With the transducer sealed at ambient pressure, the device can resolve pressure variations of about 3 mmHg, while vacuum-sealed devices do considerably better and should permit >
Using Common-Pool Resource Principles to Design Local Government Fiscal Sustainability

This article analyzes local government fiscal sustainability as a common-pool resource (CPR) problem. Comparing the experiences of Los Angeles County, San Bernardino City, and San Bernardino County, California, the analysis applies a framework developed from three decades of CPR research to show the importance of six micro-situational variables—communications with the full set of participants, known reputations of participants, high marginal per capita return, entry or exit capabilities, longer time horizon, and agreed-upon sanctioning capabilities—in shaping collective action dynamics and building the trust and reciprocity among stakeholders needed to achieve fiscal sustainability. The underlying contextual conditions for these micro-situational variables vary based on specific socioeconomic and political settings, but the findings suggest that institutions and processes can be designed based on several well-tested principles in CPR governance to encourage stakeholders to look beyond their immediate self-interests and make decisions that account for the community's long-term fiscal sustainability.
X-RAY AND SUNYAEV-ZEL'DOVICH EFFECT MEASUREMENTS OF THE GAS MASS FRACTION IN GALAXY CLUSTERS

We present gas mass fractions of 38 massive galaxy clusters at redshifts 0.14 ≤ z ≤ 0.89, derived from Chandra X-ray and OVRO/BIMA interferometric Sunyaev-Zel'dovich effect (SZE) measurements. We use three models for the gas distribution: (1) an isothermal β-model fit jointly to the X-ray data at radii beyond 100 kpc and to all of the SZE data, (2) a nonisothermal double β-model in hydrostatic equilibrium with a Navarro-Frenk-White (NFW) dark matter distribution, fit jointly to all of the X-ray and SZE data, and (3) an isothermal β-model fit only to the SZE spatial data. We show that the isothermal model well characterizes the intracluster medium outside the cluster core and provides good fits to clusters with a range of morphological properties. X-ray and SZE mean gas mass fractions for model 1 are f_(gas)(X-ray) = 0.110 ± 0.003^(+0.006)_(-0.018) and f_(gas)(SZE) = 0.116 ± 0.005^(+0.009)_(-0.027) assuming (Ω_M, Ω_Λ, h) = (0.3, 0.7, 0.7); uncertainties are statistical followed by systematic at 68% confidence. For model 2, f_(gas)(X-ray) = 0.119 ± 0.003^(+0.007)_(-0.014) and f_(gas)(SZE) = 0.121 ± 0.005^(+0.009)_(-0.016). For model 3, f_(gas)(SZE) = 0.120 ± 0.009^(+0.009)_(-0.027). The agreement in the results shows that the core can be accounted for satisfactorily by either excluding it from fits to the X-ray data or modeling the intracluster gas with a nonisothermal double β-model. We find that the SZE is largely insensitive to core structure. Our results indicate that the ratio of gas mass fraction within r_(2500) to the cosmic baryon fraction, f_(gas)/(Ω_(B)/Ω_(M)) is 0.68^(+0.10)_(-0.16), where statistical and systematic uncertainties are included at 68% confidence. By assuming that cluster gas mass fractions are independent of redshift, we find that the results agree with standard ΛCDM cosmology and are inconsistent with a flat matter-dominated (Ω_M = 1) universe.
Loss of a Conserved tRNA Anticodon Modification Perturbs Cellular Signaling

Transfer RNA (tRNA) modifications enhance the efficiency, specificity and fidelity of translation in all organisms. The anticodon modification mcm5s2U34 is required for normal growth and stress resistance in yeast; mutants lacking this modification have numerous phenotypes. Mutations in the homologous human genes are linked to neurological disease. The yeast phenotypes can be ameliorated by overexpression of specific tRNAs, suggesting that the modifications are necessary for efficient translation of specific codons. We determined the in vivo ribosome distributions at single codon resolution in yeast strains lacking mcm5s2U. We found accumulations at AAA, CAA, and GAA codons, suggesting that translation is slow when these codons are in the ribosomal A site, but these changes appeared too small to affect protein output. Instead, we observed activation of the GCN4-mediated stress response by a non-canonical pathway. Thus, loss of mcm5s2U causes global effects on gene expression due to perturbation of cellular signaling.
Robust Design of Third-Level Packaging in Portable Electronics: Solder Joint Reliability Under Dynamic Mechanical Loading

Solder joint reliability issues that can be identified only at the system level are notoriously difficult to resolve in a timely manner using trial and error experimentation alone. The particular case of solder joint reliability of a side switch in a phone subjected to drop-impact is addressed. An approach employing Response Surface Methodology (RSM) is proposed to solve reliability and robust design problems in advanced packaging. A 10x improvement in the drop test failure rate is demonstrated with a minimum of trial and error experimentation. Technical contributions are a) a novel drop life response function derived from strain energy principles, and b) an approach to address package reliability issues at the system level.
Sugar in the Caribbean: Adjusting to Eroding Preferences

Sugar exporters of the Caribbean depend on preferential sales of sugar to the European Union and United States at prices that are two to three times the world market price. Without these preferences, sugar export revenues would decline significantly. These preferences are likely to erode in the next several years as the sugar programs of both the European Union and the United States are under pressure to reform as part of already agreed international commitments, internal pressures, and the ongoing Doha Round of multilateral trade negotiations. The European Commission has already proposed reforms that would reduce internal sugar prices by 39 percent, directly affecting Caribbean sugar exporters. This presents a serious challenge to the sugar producers of the Caribbean who are mostly high-cost producers who will find it difficult to compete in the world market. St. Kitts & Nevis have recently announced plans to close their sugar industry and Trinidad & Tobago began a major restructuring program in 2003. Other sugar producers of the Caribbean will need to become more competitive by reducing costs and adding value to their sugar industries through cogeneration of energy and other activities. Those that cannot reduce costs sufficiently will need to diversify into other crops, such as fruits, vegetables, and meats, for the growing local demand, the tourist industry, or export. International assistance will be important to help countries with these adjustments and the European Union has already proposed an adjustment program.
On Relativistic Generalization of Gravitational Force

In relativistic theories, the assumption of proper mass constancy generally holds. We study gravitational relativistic mechanics of point particle in the novel approach of proper mass varying under Minkowski force action. The motivation and objective of this work are twofold: first, to show how the gravitational force can be included in the Special Relativity Mechanics framework, and, second, to investigate possible consequences of the revision of conventional proper mass concept (in particular, to clarify a proper mass role in the divergence problem). It is shown that photon motion in the gravitational field can be treated in terms of massless refracting medium, what makes the gravity phenomenon compatible with SR Mechanics framework in the variable proper mass approach. Specifically, the problem of point particle in the spherical symmetric stationary gravitational field is studied in SR-based Mechanics, and equations of motion in the Lorentz covariant form are obtained in the relativistic Lagrangean problem formulation. The dependence of proper mass on potential field strength is derived from the Euler-Lagrange equations as well. One of new results is the elimination of conventional 1/r divergence, which is known to be not removable in Schwarzschild gravitomechanics. Predictions of particle and photon gravitational properties are in agreement with GR classical tests under weak-field conditions; however, deviations rise with potential field strength. The conclusion is made that the approach of field-dependent proper mass is perspective for development of SR gravitational mechanics and further studies of gravitational problems.
Should Event Organizers Prevent Resale of Tickets

We are interested in whether preventing resale of tickets benefits the capacity providers for sporting and entertainment events. Common wisdom suggests that ticket resale is harmful to event organizers' revenues, and event organizers have tried to prevent resale of tickets. For instance, Ticketmaster recently proposed paperless nontransferrable ticketing, which would severely limit the opportunity to resell tickets. We consider a model that allows resale from both consumers and speculators with different transaction costs for each party. Surprisingly, we find that this wisdom is incorrect when event organizers use fixed pricing policies; in fact, event organizers benefit from reductions in consumers' and speculators' transaction costs of resale. Even when multiperiod pricing policies are used, we find that an event organizer may still benefit from ticket resale if his capacity is small. Although paperless ticketing is suggested as a way to reduce ticket resale and prevent speculators from buying tickets, our results suggest that it may reduce the capacity providers' revenues in many situations. Instead, we propose ticket options as a novel ticket pricing mechanism. We show that ticket options where consumers would initially buy an option to buy a ticket and then exercise at a later date naturally reduce ticket resale significantly and result in significant increases in event organizers' revenues. Furthermore, since a consumer only risks the option price and not the whole ticket price if she cannot attend the event, options may face less consumer resistance than paperless tickets. This paper was accepted by Serguei Netessine, operations management.
Stock and Bond Liquidity and its Effect on Prices and Financial Policies

An asset is liquid if it can be traded at the prevailing market price quickly and at low cost. We show that in addition to risk, liquidity affects asset prices and returns. Theories of asset pricing suggest that the expected return of an asset is increasing in its risk, because risk-averse investors require compensation for bearing more risk. Because investors are also averse to the costs of illiquidity and want to be compensated for bearing them, asset returns are increasing in illiquidity. Thus, asset prices should depend on two asset characteristics: risk and liquidity. This paper surveys research on the effects of liquidity on asset prices and returns, showing that liquidity is an important factor in capital asset pricing.
Convenient preparations of azo-dye labeled amino acids and amines

N-(4-Arylazobenzoyl)-1H-benzotriazoles 3 react with amino acids 4 and amines 6 to give azo-dye labeled amino acids (5a–m) and amines (7a–n) in high yields (74–100%) with retention of chirality.
Large Eddy Simulation of Premixed Combustion With a Thickened-Flame Approach

A Thickened Flame (TF) modeling approach is combined with a Large Eddy Simulation (LES) methodology to model premixed combustion and the accuracy of these model predictions is evaluated by comparing with the piloted premixed stoichiometric methane-air flame data of Chen et al. [Combust. Flame 107 (1996) 223–226] at a Reynolds number Re = 24,200. In the TF model, the flame front is artificially thickened to resolve it on the computational LES grid. Since the flame front is resolved, the combustion chemistry can be incorporated directly without closure approximations for the reaction rate. The response of the thickened flame to turbulence is taken care of by incorporating an efficiency function in the governing equations. The efficiency function, which is also known as a sub-grid flame wrinkling parameter, is a function of local turbulence and of the premixed flame characteristics, such as laminar flame speed and thickness. Three variants of the TF model are examined: the original Thickened Flame model, the Power-law flame wrinkling model, and the dynamically modified TF model. Reasonable agreement is found when comparing predictions with the experimental data and with computations reported using a probability distribution function (PDF) modeling approach by Lindstedt et al. [Combust. Flame 145 (2006) 495–511] and G-equation approach by Duchamp et al. [Annual Research Briefs, CTR (2000) 105–116].Copyright © 2008 by ASME
Adiabatic embedment of nanomechanical resonators in photonic microring cavities

We report a cavity optomechanical system in which a nanomechanical resonator is adiabatically embedded inside an optical ring resonator with ultralow transition loss and nearly uncompromised optical quality factor after release of the beam.
Determination of surface recombination velocity and bulk lifetime in detector grade silicon and germanium crystals

The utility of a noncontact photoconductive decay (PCD) technique is demonstrated in measuring the bulk lifetime, /spl tau//sub B/, and surface recombination velocity, S, in detector grade silicon and germanium crystals. We show that the simple analytical equations which relate the observed effective lifetimes in PCD transients to /spl tau//sub B/ and S have a limited range of applicability. The noncontact PCD technique is used to determine the effect of several surface treatments on the observed effective lifetimes in Si and Ge. A degradation of the effective lifetime in Si is reported as a result of the growth of a thin layer of native oxide at room temperature under atmospheric conditions. >
Prescribing symmetric functions of the eigenvalues of the Ricci tensor

We study the problem of conformally deforming a metric to a prescribed symmetric function of the eigenvalues of the Ricci tensor. We prove an existence theorem for a wide class of symmetric functions on manifolds with positive Ricci curvature, provided the conformal class admits an admissible metric.
NLO QCD predictions for internal jet shapes in DIS at HERA

Abstract The transverse momentum flow inside jets is a sensitive measure of internal jet structure. For the current jets in deep inelastic scattering this jet shape measure is determined at order α s 2 , i.e. with up to three partons inside a single jet. The scale dependence of jet shapes in various jet algorithms is discussed. Results agree well with recent measurements by the ZEUS Collaboration, without introducing the hadronization parameter R sep .
A system model and inversion for synthetic aperture radar imaging

A system model and its corresponding inversion for synthetic aperture radar (SAR) imaging are presented. The system model incorporates the spherical nature of a radar's radiation pattern at far field. The inverse method based on this model performs a spatial Fourier transform (Doppler processing) on the recorded signals with respect to the available coordinates of a translational radar (SAR) or target (inverse SAR). It is shown that the transformed data provide samples of the spatial Fourier transform of the target's reflectivity function. The inverse method can be modified to incorporate deviations of the radar's motion from its prescribed straight line path. The effects of finite aperture on resolution, reconstruction, and sampling constraints for the imaging problem are discussed. >
Commentary: Barriers and Opportunities to Changing the Research Agenda to Support Precaution and Primary Prevention

Abstract Conceptual research to define the Precautionary Principle and its role in science, science policy, and public health is making substantial progress. In September 2001, participants at the International Summit on Science and the Precautionary Principle developed a vision for science to address the complexity of contemporary health risks in a way that could lead to more precautionary, preventive decisions under uncertainty. Its components include: (1) a more effective linkage between research on hazards and research on primary prevention; (2) increased use of interdisciplinary approaches including better integration of qualitative and quantitative data; (3) innovative methods for analyzing cumulative and interactive effects, populations and systems and vulnerable sub-populations; (4) systems for continuous monitoring to avoid unintended consequences of actions and to identify early warnings of risks; (5) more comprehensive techniques for analyzing and communicating hazards and uncertainties; and (6...
Evaluation of Tavorite-Structured Cathode Materials for Lithium-Ion Batteries Using High-Throughput Computing

Cathode materials with structure similar to the mineral tavorite have shown promise for use in lithium-ion batteries, but this class of materials is relatively unexplored. We use high-throughput density-functional-theory calculations to evaluate tavorite-structured oxyphosphates, fluorophosphates, oxysulfates, and fluorosulfates for use as cathode materials in lithium-ion batteries. For each material we consider the insertion of both one and two lithium ions per redox-active metal, calculating average voltages and stability relative to a database of nearly 100,000 previously calculated compounds. To evaluate lithium mobility, we calculate the activation energies for lithium diffusion through the known tavorite cathode materials LiVO(PO4), LiV(PO4)F, and LiFe(SO4)F. Our calculations indicate that tavorite-structured materials are capable of very high rates of one-dimensional lithium diffusion, and several tavorite-structured materials may be capable of reversibly inserting two lithium ions per redox-active...
K. Saito's Conjecture for nonnegative eta products and analogous results for other infinite products ✩

We prove that the Fourier coefficients of a certain general eta product considered by K. Saito are nonnegative. The proof is elementary and depends on a multidimensional theta function identity. The z=1 case is an identity for the generating function for p-cores due to Klyachko [A.A. Klyachko, Modular forms and representations of symmetric groups, J. Soviet Math. 26 (1984) 1879–1887] and Garvan, Kim and Stanton [F. Garvan, D. Kim, D. Stanton, Cranks and t-cores, Invent. Math. 101 (1990) 1–17]. A number of other infinite products are shown to have nonnegative coefficients. In the process a new generalization of the quintuple product identity is derived.
The Long-Term Legacy of the Khmer Rouge Period in Cambodia

The author studies the long-term impact of genocide during the period of the Khmer Rouge (1975-79) in Cambodia and contributes to the literature on the economic analysis of conflict. Using mortality data for siblings from the Cambodia Demographic and Health Survey in 2000, he shows that excess mortality was extremely high and heavily concentrated during 1974-80. Adult males had been the most likely to die, indicating that violent death played a major role. Individuals with an urban or educated background were more likely to die. Infant mortality was also at very high levels during the period, and disability rates from landmines or other weapons were high for males who, given their birth cohort, were exposed to this risk. The very high and selective mortality had a major impact on the population structure of Cambodia. Fertility and marriage rates were very low under the Khmer Rouge but rebounded immediately after the regime's collapse. Because of the shortage of eligible males, the age and education differences between partners tended to decline. The period had a lasting impact on the educational attainment of the population. The education system collapsed during the period, so individuals-especially males-who were of schooling age during this interval had a lower educational attainment than the preceding and subsequent birth cohorts.
Spectral Learning of Latent-Variable PCFGs

We introduce a spectral learning algorithm for latent-variable PCFGs (Petrov et al., 2006). Under a separability (singular value) condition, we prove that the method provides consistent parameter estimates.
Systemic Activation and Antigen-Driven Oligoclonal Expansion of T Cells in a Mouse Model of Colitis

Transfer of CD4+CD45RBhigh T cells into immunodeficient mice results in both the expansion of the transferred T cells and colitis. Here we show that colitis pathogenesis requires expression of MHC class II molecules by the immune-deficient host. Analysis of the TCRβ repertoire of the cells found in the large intestine of diseased mice revealed a population with restricted TCR diversity. Furthermore, nucleotide sequence analysis demonstrated the selection for particular CDR3β amino acid sequence motifs. Collectively, these data indicate that the expansion of T cells in the intestine and colitis pathogenesis are likely to require the activation of Ag-specific T cells, as opposed to nonspecific or superantigen-mediated events. There is relatively little overlap, however, when the TCR repertoires of different individuals are compared, suggesting that a number of Ags can contribute to T cell expansion and the generation of a T cell population in the intestine. Surprisingly, many of the expanded clones found in the large intestine also were found in the spleen and elsewhere, although inflammation is localized to the colon. Additionally, donor-derived T cells appear to be activated in both the intestine and the spleen at early time points after cell transfer. Together, these results strongly suggest that disease induction in this model involves either the early and systemic activation of antigen-specific T cells or the rapid dispersal of T cells activated at a particular site.
On boundary value problems for Einstein metrics

On any given compact manifold M nC1 with boundary @M , it is proved that the moduli space E of Einstein metrics on M , if non-empty, is a smooth, infinite dimensional Banach manifold, at least when 1.M;@M/D 0. Thus, the Einstein moduli space is unobstructed. The usual Dirichlet and Neumann boundary maps to data on @M are smooth, but not Fredholm. Instead, one has natural mixed boundaryvalue problems which give Fredholm boundary maps. These results also hold for manifolds with compact boundary which have a finite number of locally asymptotically flat ends, as well as for the Einstein equations coupled to many other fields. 58J05, 58J32; 53C25
A Novel Route to 2,3-Pyrazol-1(5H)-ones via Palladium-Catalyzed Carbonylation of 1,2-Diaza-1,3-butadienes

A novel Pd(0)-catalyzed carbonylation of both isolable 1,2-diaza-1,3-butadienes and those generated in situ by extrusion of SO2 and CO2 from heterocyclic precursors is described. The reaction proceeds at room temperature to 110 °C under 1−2 atm of CO to afford 2,3-pyrazol-1(5H)-ones in good to excellent yields. The effect of catalyst structure and stability on the carbonylation reaction is evaluated.
Can continuous speech recognizers handle isolated speech

Abstract Continuous speech is far more natural and efficient than isolated speech for communication. However, for current state-of-the-art automatic speech recognition systems, isolated speech recognition (ISR) is far more accurate than continuous speech recognition (CSR). It is common practice in the speech research community to build CSR systems using only CS data. However, slowing of the speaking rate is a natural reaction for a user faced with the high error rates of current CSR systems. Ironically, CSR systems typically have a much higher word error rate when speakers slow down since the acoustic models are usually derived exclusively from continuous speech corpora. In this paper, we summarize our efforts to improve the robustness of our speaker-independent CSR system against speaking styles, without suffering a recognition accuracy penalty. In particular the multi-style trained system described in this paper attains a 7.0% word error rate for a test set consisting of both isolated and continuous speech, in contrast to the 10.9% word error rate achieved by the same system trained only on continuous speech.
Testbed Evaluation of Virtual Environment Interaction Techniques

As immersive virtual environment (VE) applications become more complex, it is clear that we need a firm understanding of the principles of VE interaction. In particular, designers need guidance in choosing three-dimensional interaction techniques. In this paper, we present a systematic approach, testbed evaluation, for the assessment of interaction techniques for VEs. Testbed evaluation uses formal frameworks and formal experiments with multiple independent and dependent variables to obtain a wide range of performance data for VE interaction techniques. We present two testbed experiments, covering techniques for the common VE tasks of travel and object selection/manipulation. The results of these experiments allow us to form general guidelines for VE interaction and to provide an empirical basis for choosing interaction techniques in VE applications. Evaluation of a real-world VE system based on the testbed results indicates that this approach can produce substantial improvements in usability.
CORRELATIONS IN ECONOMIC TIME SERIES

A financial index of the New York stock exchange, the SP here f× is called the crossover frequency. (iii) We confirm these results using the DFA (detrended fluctuation analysis) method (see Fig. 2b), which allows accurate estimates of exponents independent of local trends
Forgone Earnings from Smoking : Evidence for a Developing Country

The authors estimate the economic losses related to the negative effect of smoking on wages in a context of a developing country. Using data from the 2005 Albania Living Standards Monitoring Survey, they jointly estimate a system of three equations: the smoking decision and two separate wage equations for smokers and nonsmokers. The results show that, after controlling for observed characteristics and taking into account unobserved heterogeneity in personal characteristics, smoking has a substantial negative impact on wages. On average smokers' wages are 20 percent lower than the wages of similar nonsmokers, providing strong evidence for the potential policy relevance of tobacco control initiatives for developing countries.
An Efficient and Trustworthy P2P and Social Network Integrated File Sharing System

Efficient and trustworthy file querying is important to the overall performance of peer-to-peer (P2P) file sharing systems. Emerging methods are beginning to address this challenge by exploiting online social networks (OSNs). However, current OSN-based methods simply cluster common-interest nodes for high efficiency or limit the interaction between social friends for high trustworthiness, which provides limited enhancement or contradicts the open and free service goal of P2P systems. Little research has been undertaken to fully and cooperatively leverage OSNs with integrated consideration of proximity and interest. In this work, we analyze a BitTorrent file sharing trace, which proves the necessity of proximity- and interest-aware clustering. Based on the trace study and OSN properties, we propose a social network integrated P2P file sharing system with enhanced efficiency and trustworthiness (SOCNET) to fully and cooperatively leverage the common-interest, proximity-close, and trust properties of OSN friends. SOCNET uses a hierarchical distributed hash table (DHT) to cluster common-interest nodes, then further cluster proximity-close nodes into a subcluster, and connects the nodes in a subcluster with social links. Thus, when queries travel along trustable social links, they also gain higher probability of being successfully resolved by proximity-close nodes, and it simultaneously enhances efficiency and trustworthiness. We further propose different strategies to guide nodes to forward a file query to friends that are more trustworthy and more likely to resolve the queries or forward the query to file holders. We also propose follower- and cluster-based file replication algorithms to enhance file search efficiency. The results of trace-driven experiments on the real-world PlanetLab testbed demonstrate the higher efficiency, trustworthiness, and dynamism-resilience of SOCNET compared with other systems. Experimental results also confirm the effectiveness of the proposed strategies to improve SOCNET’s performance.
Secure Wireless Communication and Optimal Power Control Under Statistical Queueing Constraints

In this paper, secure transmission of information over fading broadcast channels is studied in the presence of statistical queueing constraints. Effective capacity is employed as a performance metric to identify the secure throughput of the system, i.e., effective secure throughput. It is assumed that perfect channel side information (CSI) is available at both the transmitter and the receivers. Initially, the scenario in which the transmitter sends common messages to two receivers and confidential messages to one receiver is considered. For this case, the effective secure throughput region, which is the region of constant arrival rates of common and confidential messages that can be supported by the buffer-constrained transmitter and fading broadcast channel, is defined. It is proven that this effective throughput region is convex implying that time-sharing between any two viable transmission and power control strategies results in effective throughput values inside the region. Then, the optimal power control policies that achieve the boundary points of the effective secure throughput region are investigated and an algorithm for the numerical computation of the optimal power adaptation schemes is provided. Additionally, the throughput region achieved by time-division multiplexing of common and confidential messages is explored. Subsequently, the special case in which the transmitter sends only confidential messages to one receiver is addressed in more detail. For this case, effective secure throughput is formulated and two different power adaptation policies are studied. These power adaptation policies are compared with the opportunistic ones that are optimal in the absence of quality of service (QoS) constraints. It is shown that opportunistic schemes, in which data transmission with high rates and high power occurs only when the main channel is much better than the eavesdropper channel, are no longer optimal under buffer constraints, and the transmitter should send the data at a certain moderate rate and power even when the main channel strength is comparable to that of the eavesdropper channel to avoid buffer overflows.
SPITZER REVEALS HIDDEN QUASAR NUCLEI IN SOME POWERFUL FR II RADIO GALAXIES

We present a Spitzer mid-infrared survey of 42 Fanaroff-Riley class II radio galaxies and quasars from the 3CRR catalog at redshift z 8 × 10 to the 43rd ergs s^-1, indicating strong thermal emission from hot dust in the active galactic nucleus. Our results demonstrate the power of Spitzer to unveil dust-obscured quasars. The ratio of "mid-IR luminous" narrow-line radio galaxies to quasars indicates a mean dust covering fraction of 0.56 ± 0.15, assuming relatively isotropic emission. We analyze Spitzer spectra of the 14 mid-IR luminous narrow-line radio galaxies thought to host hidden quasar nuclei. Dust temperatures of 210–660 K are estimated from single-temperature blackbody fits to the low- and high-frequency ends of the mid-IR bump. Most of the mid-IR luminous radio galaxies have a 9.7 µm silicate absorption trough with optical depth <0.2, attributed to dust in a molecular torus. Forbidden emission lines from high-ionization oxygen, neon, and sulfur indicate a source of far-UV photons in the hidden nucleus. However, we find that the other 55% ± 13% of narrow-line FR II radio galaxies are weak at 15µm, contrary to single-population unification schemes. Most of these galaxies are also weak at 30µm. Mid-IR weak radio galaxies may constitute a separate population of nonthermal, jet-dominated sources with low accretion power.
Fixed-order H∞ compensator design

A method is presented for the construction of fixed-order compensators to provide H∞ norm constraint for linear control systems with exogenous disturbances. The method is based on the celebrated bounded-real lemma that predicates the H∞ norm constraint via a Riccati inequality. The synthesis of fixed-order controllers whose dimensions are less than the order of a given plant, is demonstrated by a set of sufficient conditions along with a numerical algorithm.
Stress-Intensity Factors for Internal Surface Cracks in Cylindrical Pressure Vessels

The paper presents stress-intensity factors for a wide range of semi-elliptical surface cracks on the inside of pressurized cylinders. The ratio of crack depth to crack length ranged from 0.2 to 1; the ratio of crack depth to wall thickness ranged from 0.2 to 0.8; and the ratio of wall thickness to vessel radius was 0.1 to to 0.25. The stress-intensity factors were calculated by a three-dimensional finite-element method using singularity elements along the crack front and linear-strain elements elsewhere. An equation for the stress-intensity factors was obtained which applies over a wide range of configuration parameters and was within about 5 percent of the present results. A comparison was also made between the results and other analyses of internal surface cracks in cylinders. The results from a boundary-integral equation method were in agreement and those from another finite-element method were in fair agreement (+ or - 8 percent) with the results.
Self-assembly of 2D membranes from mixtures of hard rods and depleting polymers

We combine simulations and experiments to elucidate the molecular forces leading to the assembly of two dimensional membrane-like structures composed of a one rod-length thick monolayer of aligned rods from an immiscible suspension of hard rods and depleting polymers. Computer simulations predict that monolayer membranes are thermodynamically stable above a critical rod aspect ratio and below a critical depletion interaction length scale. Outside of these conditions alternative structures such as stacked smectic columns or nematic droplets are thermodynamically stable. These predictions are confirmed by subsequent experiments using a model system of virus rod-like molecules and non-adsorbing polymer. Our work demonstrates that collective molecular protrusion fluctuations alone are sufficient to stabilize membranes composed of homogenous rods with simple excluded volume interactions.
Metal Triflate–Catalyzed Friedel–Crafts Acetylation of 3-Phenylsydnone

Abstract Friedel–Crafts acetylation at the 4-position of 3-phenylsydnone (1) was achieved via thermal heating overnight in moderate to good yields by employing various metal triflate catalysts (5–20 mol%), lithium perchlorate (0–20 mol%), and acetic anhydride (4 equivalents) using either acetonitrile or acetic anhydride, in excess, as solvent. Six commercially available, homogeneous metal triflate catalysts were investigated, and optimal conditions were determined. The best yields overall were achieved with indium triflate. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications ® to view the free supplemental file.