cssi/SciSciGPT-SciSciNet huggingface dataset:
THE uBVI PHOTOMETRIC SYSTEM. II. STANDARD STARS

Paper I of this series described the design of a CCD-based photometric system that is optimized for ground-based measurements of the size of the Balmer discontinuity in stellar spectra. This "uBVI" system combines the Thuan-Gunn u filter with the standard Johnson-Kron-Cousins BVI filters and can be used to discover luminous yellow supergiants in extragalactic systems and post–asymptotic giant branch stars in globular clusters and galactic halos. In the present paper we use uBVI observations obtained on 54 nights with 0.9 m telescopes at Kitt Peak and Cerro Tololo to construct a catalog of standardized u magnitudes for standard stars taken from the 1992 catalog of Landolt. We describe the selection of our 14 Landolt fields and give details of the photometric reductions, including red leak and extinction corrections, transformation of all the observations onto a common magnitude system, and the establishment of the photometric zero point. We present a catalog of u magnitudes of 103 stars suitable for use as standards. We show that data obtained with other telescopes can be transformed to our standard system with better than 1% accuracy.
Control of Eukaryotic Cell Migration Through Modulation of Extracellular Chemoattractant Gradients

Cell migration is fundamental to a wide range of biological and physiological functions including: wound healing, immune defense, cancer metastasis, as well as the formation and development of biological structures such as vascular and neural networks. In these diverse processes, cell migration is influenced by a broad set of external mechanical and biochemical cues, particularly the presence of (time dependent) spatial gradients of soluble chemoattractants in the extracellular domain. Many biological models have been proposed to explain the mechanisms leading to the migratory response of cells as a function of these external cues. Based on such models, here we propose approaches to controlling the chemotactic response of eukaryotic cells by modulating their micro-environments in vitro (for example, using a microfluidic chemotaxis chamber). By explicitly modeling i) chemoattractant-receptor binding kinetics, ii) diffusion dynamics in the extracellular domain, and iii) the chemotactic response of cells, models for the migration processes arise. Based on those models, optimal control formulations are derived. We present simulation results, and suggest experimental approaches to controlling cellular motility in vitro, which can be used as a basis for cellular manipulation and control.Copyright © 2010 by ASME
FeCl3-Catalyzed aminohalogenation of arylmethylenecyclopropanes and arylvinylidenecyclopropanes and corresponding mechanistic studies.

The aminochlorination of methylenecyclopropanes (MCPs) 1 and vinylidenecyclopropanes (VCPs) has been explored with use of FeCl3 (20 mol %) as a Lewis acid catalyst in acetonitrile under convenient mild conditions. The stereochemistry has been unambiguously confirmed by X-ray structural analysis. The aziridinium-based mechanism, accounting for both regio- and stereoselectivity, has been carefully studied. A linear free-energy relationship study of this reaction confirms consistency with the Hammet equation.
Dual-state augmentation for minimizing conformance test costs

This paper discusses the dual-state augmentation method to generate the minimum-length test sequences using the multiple UIO sequences of minimal and nonminimal lengths. In dual-state augmentation, all UIO sequences (minimum-length or not) can be used to minimize the test sequence length. The resulting test sequences are significantly shorter than the test sequences generated by the existing methods which only use the minimum-length UIO sequences. As a case study, the dual-state augmentation technique is applied to a subset of the ISDN Network Layer protocol for supplementary voice services. Significant savings on test sequence length are observed.
Positive, Negative, or Null? The Effects of Maternal Incarceration on Children’s Behavioral Problems

We use data from the Fragile Families and Child Wellbeing Study to consider the effects of maternal incarceration on 21 caregiver- and teacher-reported behavioral problems among 9-year-old children. The results suggest three primary conclusions. First, children of incarcerated mothers are a disadvantaged group that exhibit high levels of caregiver- and teacher-reported behavioral problems. Second, after we adjust for selection, the effects of maternal incarceration on children’s behavioral problems are consistently null (for 19 of 21 outcomes) and rarely positive (1 of 21) or negative (1 of 21), suggesting that the poor outcomes of these children are driven by disadvantages preceding maternal incarceration rather than incarceration. These effects, however, vary across race/ethnicity, with maternal incarceration diminishing caregiver-reported behavioral problems among non-Hispanic whites. Finally, in models considering both maternal and paternal incarceration, paternal incarceration is associated with more behavioral problems, which is consistent with previous research and suggests that the null effects of maternal incarceration are not artifacts of our sample or analytic decisions.
Improved dead reckoning using caster wheel sensing on a differentially steered three-wheeled autonomous vehicle

A differentially steered three-wheeled vehicle has proven to be an effective platform for outdoor navigation. Many applications for this vehicle configuration, including planetary exploration and landmine/UXO location, require accurate localization. In spite of known problems, odometry, also called dead reckoning, remains one of the least expensive and most popular methods for localization. This paper presents the results of an investigation into the benefits of instrumenting the rear caster wheel to supplement the drive wheel encoders in odometry. A linear observer is used to fuse the data between the drive wheel encoders and the caster data. This method can also be extended using the standard form of the Kalman filter to allow for noise. Improvements in position estimation in the face of common problems such as slip and dimensional errors are quantified.
Multiple Matching of Rectangular Patterns

We describe the first worst-case efficient algorithm for simultaneously matching multiple rectangular patterns of varying sizes and aspect ratios in a rectangular text. Efficient means significantly more efficient asymptotically than applying known algorithms that handle one height (or width or aspect ratio) at a time for each height. Our algorithm features an interesting use of multidimensional range searching, as well as new adaptations of several known techniques for two-dimensional string matching. We also extend our algorithm to a dynamic setting where the set of patterns can change over time.
Radial, Turbulent Flow of a Fluid Between Two Coaxial Disks

An experimental study to determine the flow characteristics of an incompressible fluid in turbulent, radially outward flow between two coaxial, stationary disks was conducted employing a split film anemometer probe. Instantaneous velocity components in the radial and axial directions were measured; from these measurements, average velocity profiles, turbulence intensities, Reynolds stresses, energy spectra and probability density functions for the fluctuating components were computed. It is observed that the law of the wall may not be applicable everywhere. A criterion established earlier for reverse transition to laminar flow may be valid with a value of the constant smaller than suggested. A few other aspects of the flow are also discussed.
Factorization vs. flavor SU(3) in charmless B decays

Abstract Two types of predictions for charmless B decays are compared. One involves estimates based on factorization and models for form factors, while the other involves the use of flavor SU(3), sometimes with assumptions about the smallness of certain amplitudes. After a comparison of some factorization predictions with recent data, specific decays of B mesons to two charmless mesons are discussed.
Study of the Electric Field inside Microchannel Plate Multipliers

Electric field inside high gain microchannel plate multipliers was studied. The calculations were based directly on the solution of the Maxwell equations applied to the microchannel plate (MCP) rather than on the conventional lumped RC model. The results are important to explain the performance of MCP's, i) under a pulsed bias tension and, ii) at high rate conditions. The results were tested experimentally and a new method of MCP operation free from the positive ion feedback was demonstrated.
Russian Jewish Immigrants in the United States: The Adjustment of their English Language Proficiency and Earnings in the American Community Survey

This paper is concerned with the determinants of the English language proficiencies and labor market earnings of adult Russian Jewish male and female immigrants to the United States, compared to other immigrants, using the pooled files of the American Community Survey (2005–09). Although at arrival the Russian Jewish immigrants report lower levels of English skills and earnings, they experience a more rapid improvement over time, and eventually attain parity or higher levels than other immigrants. Moreover, they appear to obtain greater earnings (compared to other immigrants) in the US labor market from their schooling, their time in the United States, and their English proficiency. These findings mirror those found in earlier post-war data (1980–2000 Census) and, to the extent comparable, late 19th and early 20th century studies of Russian Jewish immigrants. An earlier version of this paper was presented at the Conference on Contemporary Russian-Speaking Jewish Diaspora, Harvard University, November 13–15, 2011.
Glycosyl transfer: a history of the concept's development and view of its major contributions to biochemistry.

Abstract Humans have fewer protein-coding genes than expected for all the inherent complexities of development. Supplementary factors include the post-translational modification of proteins by glycosylation. The latter term plus transglycosylation, glycosyltransferases, and ‘to glycosylate’ are used in biochemistry as though they always existed. Instead they have a history that can bring new insights in this science area to younger investigators. The present account describes five decades of findings and ideas on enzymic saccharide synthesis leading, finally to a rational theory that will surely continue to serve the biosciences well in the future.
Enantioselective total and formal syntheses of paroxetine (PAXIL) via phosphine-catalyzed enone α-arylation using arylbismuth(V) reagents: a regiochemical complement to Heck arylation

Abstract Exposure of dihydropyridinone 1 to the arylbismuth(V) reagent (p-F-Ph)3BiCl2 in the presence of substoichiometric quantities of tributylphosphine (10 mol %) results in aryl transfer to the transiently generated (β-phosphonio)enolate to provide the α-arylated enone 2. This transformation, which represents a regiochemical complement to the Mizoroki–Heck arylation, is used strategically in concise formal and enantioselective total syntheses of the blockbuster antidepressant (−)-paroxetine (PAXIL).
Copper(II)‐Catalyzed Silylation of Activated Alkynes in Water: Diastereodivergent Access to E‐ or Z‐β‐Silyl‐α,β‐Unsaturated Carbonyl and Carboxyl Compounds

Copper(II)-catalyzed silylation of substituted alkynylcarbonyl compounds was investigated. Through the activation of Me2PhSiBpin in water at room temperature and open atmosphere, vinylsilanes conjugated to carbonyl groups are synthesized in high yield. A surprising diastereodivergent access to olefin geometry was discovered using a silyl conjugate addition strategy: aldehydes and ketones were Z selective while esters and amides were exclusively transformed into the E products.
Adaptation of the impedance tube technique for the measurement of combustion process admittances

Abstract This paper describes the development and application of the impedance tube technique in the measurement of localized combustion process admittances. The latter are needed for combustor stability analyses. The experimental set-up consists of a tube with the combustion process to be investigated at one end and an acoustic driver at the other end. The latter is used to excite a standing wave in the tube whose structure depends upon its interaction with the combustion process. The needed combustion process admittance is determined from acoustic pressure measurements taken at several locations along the tube. The paper discusses the theoretical foundation of the experiment and the developed data reduction procedure which accounts for the presence of steady state temperature gradient, mean flow gradient and gas-phase losses in the tube. Results showing the applicability of the developed experimental technique are provided.
Ingestive taste reactivity as licking behavior

Abstract In ingestive taste reactivity analysis, the rhythmic oral motor responses observed during intraoral infusion of fluids normally ingested by rats are categorized and counted. These rhythmic movements can be likened to spout-licking in several respects. Both are emitted in the same frequency range (5–8 Hz), organized in a burst/pause pattern, and serve the function of intraoral transport of fluid into position for swallowing. The parallel suggests that a temporal pattern analysis, based on the spout-licking literature, can be fruitfully applied to the rhythmic movements that attend intraoral infusion. We provide a demonstration of such an analysis using an electromyographic (EMG) recording-based method for automated event detection. Eight rats received a 37.5% glucose solution (1.0 ml/min) in a series of 120 s infusion trials (45 s intertrial intervals) that was extended until the fluid was rejected. Movement counts declined 19.1% from the first to the last complete trial. Parameters derived from the pattern analysis (number of bursts, mean burst duration, pause durations, coefficient of variation for the distribution of within-burst intermovement intervals) were affected to a greater extent. The results indicate the potential value of temporal pattern analysis for various applications of the taste reactivity paradigm.
The intentionality of intention and action

Cognitive Science is likely to make little progress in the study of human behavior until we have a clear account of what a human action is. The aim of this paper is to present a sketch of a theory of action. I will locate the relation of intention to action within a general theory of Intentionality. I will introduce a distinction between prior intentions and intentions in actions; the concept of the experience of acting; and the thesis that both prior intentions and intentions in action are causally selfreferential. Each of these is independently motivated, but together they enable me to suggest solutions to several outstanding problems within action theory (deviant causal chains, the accordian effect, basic actions, etc.), to show how the logical structure of intentional action is strikingly like the logical structure of perceptions, and to construct an account of simple actions. A successfully performed intentional action characteristically consists of an intention in action together with the bodily movement or state of the agent which is its condition of satisfaction and which is caused by it. The account is extended to complex actions.
Copula Density Estimation by Total Variation Penalized Likelihood

Copulas are full measures of dependence among random variables. They are increasingly popular among academics and practitioners in financial econometrics for modeling comovements between markets, risk factors, and other relevant variables. A copula's hidden dependence structure that couples a joint distribution with its marginals makes a parametric copula non-trivial. An approach to bivariate copula density estimation is introduced that is based on a penalized likelihood with a total variation penalty term. Adaptive choice of the amount of regularization is based on approximate Bayesian Information Criterion (BIC) type scores. Performance are evaluated through the Monte Carlo simulation.
Ethical issues in managed care

The emergence and expected dominance of managed care has transformed every dimension of health care and created new ethical and policy questions. In particular, it has reshaped the physician-patient relationship and threatens the physician's role as a patient advocate. The paper discusses some ethical and financial issues of the managed care revolution.
Mechanical properties of compliant piezoelectric composites

The potential applications of pure piezoelectric ceramics as embedded sensors are limited by the stiffness and brittleness of these materials. To achieve a more compliant sensor, composites have been developed which incorporate calcium-modified lead titanate particles in an polymer matrix. Such compliant sensors, in thin film form, may be useful within thick composite structures such as tank hulls and helicopter blades. The mechanical response of 0 - 3 composite films of Ca-modified lead titanate in polyvinylidene fluoride-trifluoroethylene and Epon828 epoxy matrices is investigated in this work. The electrical response of these composites is currently being studied by Wenger et al. The viscoelastic properties of these thin film composites with various volume fractions have been measured over a wide range of frequencies and temperatures. The observed mechanical response of these heterogeneous materials is compared with the predictions of several simple models for such composites. Preliminary piezoelectric results are also presented.
The mixed mode crack problem in a nonhomogeneous elastic medium

Abstract A nonhomogeneous elastic medium containing a crack arbitrarily oriented with respect to the direction of property gradient is considered. The problem is solved under plane strain or generalized plane stress conditions. This is a highly simplified version of a class of physical problems that may arise in fracture mechanics studies of ceramic coatings, metal/ceramic composites and interfacial zones with continuously varying volume fractions or graded properties. The main results of the paper are the calculated mode I and II stress intensity factors. Among the questions studied are the effects of the material nonhomogeneity constant, the crack orientation, the loading conditions and the Poisson's ratio on the stress intensity factors. The stress state near the crack tip and the crack opening displacement are also briefly discussed.
Aerodynamic and Inlet Flow Characteristics of Several Hypersonic Airbreathing Missile Concepts

Four conceptual hypersonic missile configurations were examined experimentally and theoretically. Two of the concepts employed twin module bottom-mounted engines and two were designed for upper-surface inlets or engines with the intent of reducing the vehicle observables. The tests were conducted at Mach 6 and Reynolds numbers of 6 to 7.5 x 106/ft. Flowfield surveys in the vicinity of the engine inlet were made on all configurations and force and moment tests were conducted on three of the vehicles. Stability and control characteristics of the bottom-mounted engine configurations which incorporated low, slender wings were dominated by strong vortices that promoted severe pitchup tendencies. The shock layer and flow quality in the vicinity of the bottommounted engine inlets were dependent on nose shape. The spatula-like upper-surface engine concept demonstrated good performance and had uniform flow entering the engine inlet, while the upper-surface inlet concept with a highly swept forebody incurred large gradients due to interactions with leading-edge shocks.
Synthetic approaches to 2-(4-hydroxy-7-chromanyl)benzoic acids as antagonists of leukotriene B4.

Abstract Structural modification of 1 led to a series of 2-(4-hydroxy-7-chromanyl)benzoic acid LTB 4 antagonists exemplified by 2 and 3 . The use of an organostannane biaryl coupling, a non stereoselective reduction and a chromatographic resolution limited the utility of this synthetic route. To address these issues, a new synthetic route was developed utilizing a palladium catalyzed coupling of aryl oxazolines in tandem with a stereospecific enone reduction as key synthetic steps. Resolution was achieved by fractional crystallization of a ( S )-(−)- α -methylbenzylamine salt.
Stronger inflammatory/cytotoxic T-cell response in women identified by microarray analysis

Women develop chronic inflammatory autoimmune diseases more often than men. The mechanisms causing the increased susceptibility are incompletely understood. Chronic immune stimulation characterizes many autoimmune disorders. We hypothesized that repeated stimulation may cause a different T-cell response in women than in men. Microarrays were used to compare gene expression in T cells from healthy men and women with and without repeated stimulation. Four days after a single stimulation, only 25% of differentially expressed, gender-biased genes were expressed at higher levels in women. In contrast, after restimulation, 72% were more highly expressed in women. Immune response genes were significantly over-represented among the genes upregulated in women and among the immune response genes, the inflammatory/cytotoxic effector genes interferon-γ (IFN-γ), lymphotoxin β (LTβ), granzyme A (GZMA), interleukin-12 receptor β2 (IL12Rβ2), and granulysin (GNLY) were among those overexpressed to the highest degree. In contrast, IL17A was the only effector gene more highly expressed in men. Estrogen response elements were identified in the promoters of half the overexpressed immune genes in women, and in <10% of the male-biased genes. The differential expression of inflammatory/cytotoxic effector molecules in restimulated female T cells may contribute to the differences in autoimmune diseases between women and men.
Copolymer 1 reduces relapse rate and improves disability in relapsing‐remitting multiple sclerosis Results of a phase III multicenter, double‐blind, placebo‐controlled trial

We studied copolymer 1 (Copaxone) in a multicenter (11-university) phase III trial of patients with relapsing-remitting multiple sclerosis (MS). Two hundred fifty-one patients were randomized to receive copolymer 1 (n = 125) or placebo (n = 126) at a dosage of 20 mg by daily subcutaneous injection for 2 years. The primary end point was a difference in the MS relapse rate. The final 2-year relapse rate was 1.19 +/- 0.13 for patients receiving copolymer 1 and 1.68 +/- 0.13 for those receiving placebo, a 29% reduction in favor of copolymer 1 (p = 0.007) (annualized rates = 0.59 for copolymer 1 and 0.84 for placebo). Trends in the proportion of relapse-free patients and median time to first relapse favored copolymer 1. Disability was measured by the Expanded Disability Status Scale (EDSS), using a two-neurologist (examining and treating) protocol. When the proportion of patients who improved, were unchanged, or worsened by > or = 1 EDSS step from baseline to conclusion (2 years) was evaluated, significantly more patients receiving copolymer 1 were found to have improved and more receiving placebo worsened (p = 0.037). Patient withdrawals were 19 (15.2%) from the copolymer 1 group and 17 (13.5%) from the placebo group at approximately the same intervals. The treatment was well tolerated. The most common adverse experience was an injection-site reaction. Rarely, a transient self-limited systemic reaction followed the injection in 15.2% of those receiving copolymer 1 and 3.2% of those receiving placebo.(ABSTRACT TRUNCATED AT 250 WORDS)
The upper bound of Frobenius related length functions

Abstract In this paper, we study the asymptotic behavior of lengths of Tor modules of homologies of complexes under the iterations of the Frobenius functor in positive characteristic. We first give upper bounds to this type of length functions in lower dimensional cases and then construct a counterexample to the general situation. The motivation of studying such length functions arose initially from an asymptotic length criterion given in [S.P. Dutta, Intersection multiplicity of modules in the positive characteristics, J. Algebra 280 (2004) 394–411] which is a sufficient condition to a special case of nonnegativity of χ ∞ . We also provide an example to show that this sufficient condition does not hold in general.
Valuing Illiquid Common Stock

Illiquid common stock is worth less than stock that can be readily sold because the investor incurs an opportunity cost by being locked into the investment. Quantifying the amount of this illiquidity discount is an important issue in valuing certain common stock, especially for estate valuations. We examine whether a previously developed analytical model for valuing the lost “option to sell” when a stock is illiquid is a useful, practical tool for valuing illiquid common stock.
SHOULD PERSONS WITH DIABETES BE LICENSED TO DRIVE TRUCKS? -- RISK MANAGEMENT

How should a regulatory agency interpret a risk analysis that concludes there is a small increase in risk? The agency must decide on behalf of society whether the increased risk is large enough to justify banning the risky activity or taking some other step to lessen the risks. In a companion paper (Songer et al.), we conclude that licensing insulin using persons to drive commercial motor vehicles in interstate commerce would result in 42 additional crashes each year. Here we address risk management issues by interpreting the number of additional crashes and the relative risks of the prospective handicapped drivers. Are the number of additional crashes (42) significant? Is the increase in the annual crash risk (from 0.00785 to 0.032 for non-insulin dependent and 0.048 for insulin dependent persons) significant? Are the relative risks significant for all insulin using drivers (4.7)? For drivers with a history of severe hypoglycemic reactions (19.8)? How should society tradeoff risk increases for increases in opportunity for these handicapped persons? We review other social decisions concerning highway safety: Accepting the increasing risks of letting 16 year olds drive, allowing extremely light cars, allowing some unsafe highways, and allowing extremely unsafe driving conditions at some times of day. We conclude that the additional risks from insulin using persons are well within the current accepted range of risks.(ABSTRACT TRUNCATED AT 250 WORDS) Language: en
The influence of inhalation injury and pneumonia on burn mortality

In order to assess the specific effects of inhalation injury and pneumonia on mortality in burn patients, the records of 1058 patients treated at a single institution over a five-year period, 1980-1984, were reviewed. Of these patients, 373 (35%) had inhalation injury diagnosed by bronchoscopy and/or ventilation perfusion lung scan. Of the 373 patients, 141 (38%) had subsequent pneumonia. Among the patients without inhalation injury, pneumonia occurred in 60 of 685 (8.8%). A multiple logistic equation was developed to estimate expected mortality at any age and burn size for patients without either inhalation injury or pneumonia, with either alone, or with both. Subtraction of the expected mortality without either inhalation injury or pneumonia from the expected mortality in the presence of either or both permitted the estimation of additional mortality attributable to these complications. Inhalation injury alone increased mortality by a maximum of 20% and pneumonia by a maximum of 40%, with a maximum increase of approximately 60% when both were present. The influence on mortality was maximal in the midrange of expected mortality without these complications for any age group. These data indicate that inhalation injury and pneumonia have significant, independent, additive effects on burn mortality and that these effects vary with age and burn size in a predictable manner.
A Relaxation Solution for Transonic Flow over Three-Dimensional Jet-Flapped Wings

An algorithm has been developed which treats transonic flow over jet-flapped wings of general plan form within a small disturbance framework. The numerical method represents a generalization of the relaxation solutions developed by Bailey and Ballhaus for unblown wings and the authors' previous work for twodimensional jet-flapped airfoils, and it incorporates a new far field which accounts for the vorticity on the jet. Supercritical results presented for a variety of blown planforms indicate repeal of the Kutta condition, as in two dimensions, appreciable spanwise load carryover for partial span blowing, and reduction in lift augmentation due to sweepback. Comparison of lift coefficients with experimental values shows good agreement for various planforms.
Economics of a conceptual 75 MW hot dry rock geothermal electric power-station

Man-made, Hot Dry Rock (HDR) geothermal energy reservoirs have been investigated for over ten years. As early as 1977 a research-sized reservoir was created at a depth of 2.9 km near the Valles Caldera, a dormant volcanic complex in New Mexico, by connecting two wells with hydraulic fractures. Thermal power was generated at rates of up to 5 MW(t) and the reservoir was operated for nearly a year with a thermal drawdown less than 10/sup 0/C. A small 60kW(e) electrical generation unit using a binary cycle (hot geothermal water and a low boiling point organic fluid, R-114) was operated. Interest is now worldwide with field research being conducted at sites near Le Mayet de Montagne, France; Falkenberg and Urach, Federal Republic of Germany; Yakedake, Japan; and Rosemanowes quarry in Cornwall, United Kingdom. To assess the commercial viability of future HDR electrical generating stations, an economic modeling study was conducted for a conceptual 75 MW(e) generating station operating at conditions similar to those prevailing at the New Mexico HDR site. The reservoir required for 75 MW(e), equivalent to 550 MW of thermal energy, uses at least 9 wells drilled to 4.3 km and the temperature of the water produced should averagemore » 230/sup 0/C. Thermodynamic considerations indicate that a binary cycle should result in optimum electricity generation and the best organic fluids are refrigerants R-22, R-32, R-115 or R-600a (Isobutane). The break-even bus bar cost of HDR electricity was computed by the levelized life-cycle method, and found to be competitive with most alternative electric power stations in the US.« less
An analysis of kin-provided child care in the context of intrafamily exchanges: Linking components of family support for parents raising young children

Little is known about why parents choose kin-provided child care and less is known about how kin-provided child care is related to other forms of in-kind support from relatives close-at-hand. Previous models of the choice of kin-provided child care assumed that the presence of other forms of in-kind support from relatives nearby was inconsequential to estimating effects of economic and demographic factors on the decision to use kin-provided child care. Using data from the National Longitudinal Survey of the Class of 1972, this study shows that this assumption is incorrect because use of kin-provided child care and intrafamily in-kind resource exchanges are interrelated. When the association between use of kin-provided child care and the presence of other family in-kind exchanges is ignored, the study shows that estimated effects for income, the price of child care, and maternal characteristics are underestimated. The findings provide a better understanding of why parents choose kin-provided child care by confirming that this decision is a part of a larger set of parental decisions about involvement in resource exchanges within extended families. My findings support recent child care bills aiming to increase parental choice of child care provider, broaden the definition of a provider to include non-coresident relatives, and expand price subsidies for kin-provided child care.
Tissue Doppler echocardiography

Tissue Doppler echocardiography (TDE) is a relatively recent addition to the diagnostic ultrasonographic examination. This is similar to routine Doppler ultrasonography to assess blood flow, but technologic features focus on lower velocity frequency shifts. Two techniques are used to assess myocardial function: pulsed TDE and color-coded TDE. A great deal of data has been generated on TDE over the last 5 years, and this review allows for only a small portion of these emerging data to be discussed. One clinical application is to assess peak systolic mitral annular velocity from the apical windows as an index of global ventricular function. The six-site average for peak systolic mitral annular velocity by the color-coded TDE method of greater than 5.4 cm/sec is predictive of an ejection fraction greater than 50% with an 88% sensitivity and a 97% specificity. An emerging application is to use pulsed-TDE to assess ventricular filling pressures. The mitral annular to inflow ratio (E/Ea) greater than 10 is predictive of a mean pulmonary capillary wedge pressure greater than 15 mm Hg with a 92% sensitivity and 80% specificity. Another application is to use peak early diastolic velocity to help differentiate constrictive pericarditis from restrictive cardiomyopathy. Peak early diastolic velocity is blunted with restrictive cardiomyopathy and preserved with constrictive pericarditis. These are just a few of the many evolving clinical applications of this new quantitative diagnostic ultrasonographic method.
Direct Leuckart-type reductive amination of aldehydes and ketones: a facile one-pot protocol for the preparation of secondary and tertiary amines

A high-yielding and facile one-pot Leuckart-type reaction for rapid access to a number of 2° and 3° amines is described.
The price of admission: Who gets into private school, and how much do they pay?

Abstract I analyze how elementary and secondary private schools decide which students to admit from their applicant pool using mechanism design theory. The problem for an individual private school of who to admit and how much to charge in tuition, is complicated by the existence of peer-effects: the value students place on attending school is increasing with the average ability of the entire class at that school. This feature, coupled with the fact that students can always attend public school for free, places constraints on the types of classes the private school can admit. In my model, students have an ability type that is known to the school through testing, as well as a wealth type that is private information. Students report their wealth to the school and on the basis of the results from the ability test and wealth reports, the school institutes an allocation rule and a payment rule. Allocation rules which only admit all high ability students and no others, or all high wealth students and no others are not feasible. I utilize a simple example to show how in a revenue-maximizing allocation, the private school always under-admits the highest ability students relative to the allocation rule that maximizes social welfare.
THE DIURNAL PRESSURE OSCILLATION ON A HEATED MOUNTAIN ISLAND

Abstract A theory is developed for the 24-hr component of the diurnal pressure oscillation and compared with observations on Haleakala Mountain, Hawaii. Using the linearized hydrodynamic equations, the theory for flow over an unheated mountain is combined with the theory for flow over a flat heated island and applied to a diurnally heated mountain ridge of infinite extent perpendicular to an undisturbed current. An appropriate heating function is deduced whose variation in the vertical embodies the eddy conduction of heat. The development is also applied to an infinite ridge oriented parallel to the undisturbed current. The two ridge models are then superposed to obtain a surface more closely approximating an isolated mountain, and the distribution of the pressure perturbation over this surface is calculated. Measurements of the 24-hr component of the diurnal pressure oscillation at ten stations on Haleakala are presented. It is demonstrated that an accurate measure of the 24-hr component may be obtained ...
The 2001 Los Angeles Mayoral Election: Implications for Deracialization and Biracial Coalition Theories

In this study, we analyze the voting behavior of Whites, African Americans, and Latinos during the 2001 Los Angeles mayoral race within the context of deracialization and biracial coalition theories. We examine two questions: Why did the majority of African American voters reject a liberal, multiracial coalition for a Latino candidate in favor of a coalition of conservative Whites and Asian Americans in support of a White candidate? What implications does this campaign have for deracialized campaigns, for multiracial coalitions, and generally for the role of race in American elections? We find that effective deracialized campaigns do not always result in victories. In June 2001, James Hahn ran a successful campaign by capitalizing upon the divisions among two groups, African Americans and Latinos, which traditionally have joined coalitions in support of liberal candidates.
FOREIGN AFFILIATE ACTIVITY AND U.S. SKILL UPGRADING.

There has been little analysis of the impact of inward foreign direct investment (FDI) on U.S. wage inequality, even though the presence of foreign-owned affiliates in the United States has arguably grown more rapidly in significance for the U.S. economy than trade flows. Using U.S. manufacturing data from 1977 to 1994, we find that inward FDI has not contributed to U.S. within-industry skill upgrading. In fact, the 1980s wave of Japanese greenfield investments was significantly correlated with lower, not higher, relative demand for skilled labor. This casts doubt upon one possible channel of skill-biased technological change that was previously unexplored.
Probing dark matter substructure with pulsar timing

We demonstrate that pulsar timing measurements may potentially be able to detect the presence of dark matter substructure within our own Galaxy. As dark matter substructure transits near the line of sight between a pulsar and an observer, the change in the gravitational field will result in a delay of the light travel-time of photons. We calculate the effect of this delay due to transiting dark matter substructure and find that the effect on pulsar timing ought to be observable over decadal time-scales for a wide range of substructure masses and density profiles. We find that transiting dark matter substructure with masses above 10 -2 M ⊙ ought to be detectable at present by these means. With improved measurements, this method may be able to distinguish between baryonic, thermal non-baryonic, and non-thermal non-baryonic types of dark matter. Additionally, information about structure formation on small scales and the density profiles of Galactic dark matter substructure can be extracted via this method.
Crystal and molecular structures of tetranuclear metal clusters of copper(I) trithioperoxybenzoates

Abstract Two new tetrameric orange–red copper(I) cluster compounds, tetrakis[2,4,6-trimethyltrithioperoxybenzoato]tetracopper(I), Cu4[2,4,6-(CH3)3C6H2CS2S]4 (1) and tetrakis[o-methyltrithioperoxybenzoato]tetracopper(I), Cu4[o-CH3C6H4CS2S]4 (2) have been synthesized and their crystal and molecular structures determined by single crystal X-ray diffraction. The anionic ligands used for the syntheses were dithiobenzoates and the starting copper reagent was divalent copper. Thus oxidation of the ligand by the copper preceded cluster formation. The molecules of each cluster consist of four roughly tetrahedrally disposed, possibly weakly bonded, copper atoms each coordinated, and more clearly bonded, to three sulfur atoms.
Stability analysis of multiloop, multirate sampled systems.

Two analytical procedures are presented for determining the stability of multirate systems. These procedures are oriented toward digital computer implementation and offer substantial advantages over existing techniques from the computational standpoint. Frequency domain identities are developed which allow the expression of a system's sampled variables in terms of one basic sampling rate. The first method is restricted to systems whose sampling rates are such that the ratio of any two of them is an integer (or its reciprocal). A closed form of the system characteristic equation is obtained by applying the identities to expressions relating the various sampled quantities. Application of the second method requires only that the ratio of any two sampling rates be a rational number. The sampling identities are applied to the system closed-loop relation. Successive shifts in the Laplace variable are introduced to obtain a set of independent algebraic equations that are written in matrix form. The determinant of the matrix is the characteristic equation of the system. Nyquist stability techniques are employed to determine the stability of the system through the numerical evaluation of the characteristic determinant. Both procedures are illustrated by applying them to an example of a multiloop, multirate feedback system.
Admittance Spectroscopy of Polycrystalline ZnO‐Bi2O3 and ZnO‐BaO Systems

Admittance spectroscopy was used to characterize the bulk electron traps in polycrystalline ZnO-Bi2O3 and ZnO-BaO systems. Temperatures from 30 to 350 K and a frequency range from 1.0 to 33.3 kHz were used. Admittance spectra for the ZnO-Bi2O3 system showed large variations with sintering atmosphere and heat treatment. A trap is observed at 0.33 eV below the conduction band edge in both systems. This trap is likely to be associated with an ionized oxygen vacancy. A possible explanation of primitive varistor characteristics in terms of the roles of the electronic defects is presented.
Optimal bandwidth choice for density-weighted averages☆

Abstract This paper characterizes the optimal bandwidth value for estimating density-weighted averages, statistics that arise in semiparametric estimation methods for index models and models of selected samples based on nonparametric kernel estimators. The optimal bandwidth is derived by minimizing the leading terms of mean squared error of the density-weighted average. The optimal bandwidth formulation is developed by comparison to the optimal pointwise bandwidth of a naturally associated nonparametric estimation problem, highlighting the role of sample size and the structure of nonparametric estimation bias. The methods are illustrated by estimators of average density, density-weighted average derivatives, and conditional covariances, and bandwidth values are calculated for normal designs. A simple ‘plug-in’ estimator for the optimal bandwidth is proposed. Finally, the optimal bandwidth for estimating ratios of density-weighted averages is derived, showing that the earlier optimal formulae can be implemented directly using naturally defined ‘residual’ values.
The Energy Distribution of Gamma-Ray Bursts

The distribution of the apparent total energy emitted by a gamma-ray burst reflects not only the distribution of the energy actually released by the burst engine, but also the distribution of beaming angles. Using the observed energy fluences, the detection thresholds, and burst redshifts for three burst samples, I calculate the best-fit parameters for lognormal and power-law distributions of the apparent total energy. Two of the samples include a small number of bursts with spectroscopic redshifts, while the third sample has 220 bursts with redshifts determined by the proposed variability-luminosity correlation. I find different sets of parameter values for the three burst samples. The Bayesian odds ratio cannot distinguish between the two model distribution functions for the two smaller burst samples with spectroscopic redshifts, but does favor the lognormal distribution for the larger sample with variability-derived redshifts. The data do not rule out a distribution with a low-energy tail that is currently unobservable. I find that neglecting the burst detection threshold biases the fitted distribution to be narrower with a higher average value than the true distribution; this demonstrates the importance of determining and reporting the effective detection threshold for bursts in a sample.
Sterile neutrino states

Neutrino masses are likely to be a manifestation of the right-handed, or sterile neutrinos. The number of sterile neutrinos and the scale of their Majorana masses are unknown. We explore theoretical arguments in favor of the high and low scale seesaw mechanisms, review the existing experimental results, and discuss the astrophysical hints regarding sterile neutrinos.
Predicting Cyber Attack Rates With Extreme Values

It is important to understand to what extent, and in what perspectives, cyber attacks can be predicted. Despite its evident importance, this problem was not investigated until very recently, when we proposed using the innovative methodology of gray-box prediction. This methodology advocates the use of gray-box models, which accommodate the statistical properties/phenomena exhibited by the data. Specifically, we showed that gray-box models that accommodate the long-range dependence phenomenon can predict the attack rate (i.e., the number of attacks per unit time) 1-h ahead-of-time with an accuracy of 70.2%–82.1%. To the best of our knowledge, this is the first result showing the feasibility of prediction in this domain. We observe that the prediction errors are partly caused by the models’ incapability in predicting the large attack rates, which are called extreme values in statistics. This motivates us to analyze the extreme-value phenomenon, using two complementary approaches: 1) the extreme value theory (EVT) and 2) the time series theory (TST). In this paper, we show that EVT can offer long-term predictions (e.g., 24-h ahead-of-time), while gray-box TST models can predict attack rates 1-h ahead-of-time with an accuracy of 86%–87.9%. We explore connections between the two approaches, and point out future research directions. Although our prediction study is based on specific cyber attack data, our methodology can be equally applied to analyze any cyber attack data of its kind.
Refined intersection products and limiting linear subspaces of hypersurfaces

Let $X$ be a hypersurface of degree $d$ in $\Bbb P^n$ and $F_X$ be the scheme of $\Bbb P^r$'s contained in $X$. If $X$ is generic, then $F_X$ will have the expected dimension (or empty) and its class in the Chow ring of $G(r+1,n+1)$ is given by the top Chern class of the vector bundle $S^dU^*$, where $U$ is the universal subbundle on the Grassmannian $G(r+1,n+1)$. When we deform a generic $X$ into a degenerate $X_0$, the dimension of $F_X$ can jump. In this case, there is a subscheme $F_{lim}$ of $F_{X_0}$ with the expected dimension which consists of limiting $\Bbb P^r$'s in $X_0$ with respect to a general deformation. The simplest example is the well-known case of $27$ lines in a generic cubic surface. If we degenerate the surface into the union of a plane and a quadric, then there are infinitely many lines in the union. Which $27$ lines are the limiting ones and how many of them are in the plane and how many of them are in the quadric? The goal of this paper is to study $F_{lim}$ in general.
Making sense of surface structure

Abstract Electronic-structure calculations based on the local-density-functional approximation generally agree with measured surface atomic geometries and electron energy-level dispersions. Such calculations provide insight, not easily accessible from experiment alone, into the nature of bonding at surfaces. The result is that we can often interpret and sometimes even predict both static surface geometry and the mechanisms of surface dynamical processes.
Polarization Optimality of Equally Spaced Points on the Circle for Discrete Potentials

We prove a conjecture of Ambrus, Ball and Erdelyi that equally spaced points maximize the minimum of discrete potentials on the unit circle whenever the potential is of the form $$\begin{aligned} \sum _{k=1}^n f(d(z,z_k)), \end{aligned}$$źk=1nf(d(z,zk)),where $$f:[0,\pi ]\rightarrow [0,\infty ]$$f:[0,ź]ź[0,ź] is non-increasing and convex and $$d(z,w)$$d(z,w) denotes the geodesic distance between z and w on the circle.