cssi/SciSciGPT-SciSciNet huggingface dataset:
More thoughts on the physician's constitutional role in abortion and related choices.

This sequel to a 1985 article pursues the idea that the doctor rather than the woman seeking the abortion stands at the center of the Court’s cases protecting a constitutional right to abortion. How does this idea play out in a range of more particularized contexts? The essay concludes that recentering the analysis to focus on the woman, decoupled from the doctor, would help resolve questions posed by special informed consent requirements for abortion, the advent of medication abortion, restrictions on fetal tissue transplantation, nonconsensual Caesarian deliveries, and limitations on access to assisted reproductive technologies.
Improving the quality of software quality determination processes

Abstract This paper suggests a systematic, orderly, process-based approach to stating software qual- ity objectives and knowing if and when they have been achieved. We suggest that quality in software is a complex, multifaceted array of characteristics, and that it is important to establish specific objectives along various software quality dimensions as requirements for software quality assurance determination processes. We propose that process technology be used to design, code, execute, evaluate, and migrate processes that are demonstrably effective in achieving required software product quality objectives. Recently there have been numerous highly visible efforts to codify the assessment of software processes, and to use assessment results to improve them. In this paper we argue that these efforts function as testplans for software processes. We borrow some of the notions proposed in these efforts, and indicate how they can be used to construct a discipline of measuring and evaluating how well processes can be expected to deliver specific knowledge about software product qualities. We look towards the gradual, but eventual, establishment of an orderly discipline of software quality demonstration process development that should ultimately support a marketplace in which definitive knowledge about the nature of software products can be bought and sold.
Optimal Production Inputs with Varying Quality and Yield Components: Irrigation Termination of Upland

We utilize Classification and Regression Tree analysis to categorize the return of extending the season for upland. High, medium, and low values for cost of water, lint prices, and quality discount/premiums were applied to the lint yield and quality differentials realized from 198 irrigation termination experiments conducted in central Arizona for the crop years of 1991, 1992, 1994, 1996, 1996, 1997, and 2000. The progression of each crop was analyzed using heat units (86/55 F). The relative ranking results of CART, where the most important variable is normalized on 100, were: variety (100), additional heat units after IT-1 (94), yield of IT-1 (93), crop year (83), micronaire associated with IT-1 (68), HUAP for IT-1 (67), lint price (5), water cost (2), and the quality discount/premium year (.09). Significant yield variation from extending the season was found. In addition, agronomic signals for predicting micronaire changes were very important for determining profitability since quality is impacted for both base and any additional yields attained. These are the primary reasons why agronomic factors were found to be more influential than the economic factors considered for explaining the profitability of extending the season for upland.
The Mystery of Missing Real Spillovers in Southern Africa: Some Facts and Possible Explanations

Anecdotal evidence suggests that the economies of South Africa and its neighbors (Botswana, Lesotho, Mozambique, Namibia, Swaziland, and Zimbabwe) are tightly integrated with each other. There are important institutional linkages. Across the region there are also large flows of goods and capital, significant financial sector interconnections, as well as sizeable labor movements and associated remittance flows. These interconnections suggest that South Africa’s GDP growth rate should affect positively its neighbors’, a point we illustrate formally with the help of numerical simulations of the IMF’s GIMF model. However, our review and update of the available econometric evidence suggest that there is no strong evidence of real spillovers in the region after 1994, once global shocks are controlled for. More generally, we find no evidence of real spillovers from South Africa to the rest of the continent post-1994. We investigate the possible reasons for this lack of spillovers. Most importantly, the economies of South Africa and the rest of Sub-Saharan Africa might have de-coupled in the mid-1990s. That is when international sanctions on South Africa ended and the country re-integrated with the global economy, while growth in the rest of the continent accelerated due to a combination of domestic and external factors.
Effectiveness of Preference Elicitation in Combinatorial Auctions

Combinatorial auctions where agents can bid on bundles of items are desirable because they allow the agents to express complementarity and substitutability between the items. However, expressing one's preferences can require bidding on all bundles. Selective incremental preference elicitation by the auctioneer was recently proposed to address this problem [4], but the idea was not evaluated. In this paper we show, experimentally and theoretically, that automated elicitation provides a large benefit. In all of the elicitation schemes under study, as the number of items for sale increases, the amount of information elicited is a vanishing fraction of the information collected in traditional "direct revelation mechanisms" where bidders reveal all their valuation information. Most of the elicitation schemes also maintain the benefit as the number of agents increases. We develop more effective elicitation policies for existing query types. We also present a new query type that takes the incremental nature of elicitation to a new level by allowing agents to give approximate answers that are refined only on an as-needed basis. In the process, we present methods for evaluating different types of elicitation policies.
Robustness of null broadening against source motion

Adaptive array beamforming achieves high resolution and sidelobe suppression by producing sharp nulls in the adaptive beampattern when using sample matrix inversion (SMI). In the presence of source motion, the adaptive processor often cannot provide sufficient nulling of the interferer, given the number of snapshots available, and this results in a masking of the desired target signal. The null broadening approach, originally developed to improve the robustness of adaptive beamforming for a stationary problem, is extended to the snapshot-deficient problem arising from the nonstationarity of the background interference. Null broadening allows strong interferers to move through resolution cells and increases the number of degrees of freedom, thereby improving the detection of weak stationary signals. Numerical simulations demonstrate the robustness of the null broadening approach.
Nonlinear prediction of the aerodynamic loads on lifting surfaces

A numerical procedure is used to predict the nonlinear aerodynamic characteristics of lifting surfaces of low aspect ratio at high angles of attack for low subsonic Mach numbers. The procedure utilizes a vortex-lattice method and accounts for separation at sharp tips and leading edges. The shapes of the wakes emanating from the edges are predicted, and hence the nonlinear characteristics are calculated. Parallelogram and delta wings are presented as numerical examples. The numerical results are in good agreement with the experimental data.
Government Liability In Tort

It is when we come to the municipal corporation as an agency of the public power that we find the greatest confusion to prevail, not only as to the substantive liability or immunity of the corporation in tort, but as to the grounds upon which the liability or immunity, as the case may be, properly rests. In few, if any, branches of the law have the courts labored more abjectly under the supposed inexorable donination of formulas, phrases and terminology, with the result that facts have often been tortured into the framework of a formula, lacking in many cases any sound basis of reason or policy. This is notably the case in the effort to apply the supposedly settled rule that the municipal corporation is not liable for torts conunitted by its agents in the performance of governmental, political or public functions, whereas it is liable when the tort is committed in the performance of corporate, private or ministerial functions. Not all courts, however, are equally submissive to the commands of a ritual; so that we find the utmost confusion among the courts in the attempt to classify particular acts of state agents as governmental or corporate. Disagreement among the courts as to many customary municipal acts and functions may almost be said to be more common than agreement and the elaboration of the varying justifications for their classification is even less satisfying to any demand for principle in the law. Indeed, so hopeless did the effort of the courts to make an appropriate classification of functions appear to the Supreme Court of South Carolina that they determined to abandon the distinction between governmental and corporate acts.'87 But instead of holding the municipality liable in tort in all cases, as the late Judge Wanamaker of the Ohio Supreme Court recently suggested as desirable,188 the South Carolina court decided to
Do high and volatile levels of public investment suggest misconduct ? the role of institutional quality

This paper investigates the impact of institutional quality on public investment levels over the period 1984-2008. Moreover, it studies how the volatility of public investment and the quality of infrastructure are affected by institutional quality, and explores the contribution of other critical factors. The findings suggest an inverse relationship between public investment levels and institutional quality, supporting the idea that governments use public investment as a vehicle for rent-seeking or to compensate for the fall in private investment due to the poor business environment. In addition, aid flows, revenues and abundance of natural resources contribute positively to the level of capital spending. The author also finds that high volatility of public investment is associated with a lower quality of governance. An increase in revenues is associated with a reduction in the volatility of capital spending, suggesting that proper macroeconomic management smoothes the investment cycle. Finally, the paper provides some tentative evidence of a positive relationship between institutional quality and the quality of infrastructure.
A REVIEW OF RAIL—WHEEL CONTACT STRESS PROBLEMS

ABSTRACT From its earliest days, railroad technology has been limited by an inadequate understanding of the mechanics of load transfer between wheel and rail. It is the purpose of this paper to indicate the major problems in this area, and to review the progress made to date in the solution thereof. Attention is focussed upon investigations of the stresses (normal pressure and tangential shear) on the contact patch, rather than upon studies of bending stresses in the rail. The physical basis of Hertz's widely used analysis is outlined, and the assumptions and limitations of that analysis are indicated. The need is shown for the development of solutions to important non-Hertzian problems such as: conformai contact (e.g. between worn wheels and track), contact of rough bodies, rolling friction, adhesion, and creep. The literature on these problems, as well as work in progress, is reviewed. A detailed mathematical treatment is avoided, but the principal results of much of the theory are illustrated through geometrical and physical descriptions. Recent works on the effects of surface waviness, plastic deformation, and residual stresses in rail, are reviewed.
A Spectrum Sharing Scheme in Two Cellular Wireless Networks

In this paper, we propose and investigate a spectrum sharing scheme in two cellular wireless networks. This scheme specifies various considerations of how to share the licensed radio spectrum of one network with another, including how to rent out the spectrum to another network and how to withdraw the original spectrum from the renting network. For each network, we figure out explicit expressions for important system performance measures, which include blocking probability of new calls and handoff calls and system throughput. We also show how to adjust our spectrum sharing scheme to achieve a better result for each of above performance measures.
Coloring Triple Systems with Local Conditions

We produce an edge-coloring of the complete 3-uniform hypergraph on n vertices with eOloglogn colors such that the edges spanned by every set of five vertices receive at least three distinct colors. This answers the first open case of a question of Conlon-Fox-Lee-Sudakov Int Math Res Not, to appeari¾? who asked whether such a coloring exists with logno1 colors.
Convergence Time for Unbiased Quantized Consensus Over Static and Dynamic Networks

In this paper, the question of expected time to convergence is addressed for unbiased quantized consensus on undirected connected graphs, and some strong results are obtained. The paper first provides a tight expression for the expected convergence time of the unbiased quantized consensus over general but fixed networks. It is shown that the maximum expected convergence time lies within a constant factor of the maximum hitting time of an appropriate lazy random walk, using the theory of harmonic functions for reversible Markov chains. Following this, and using electric resistance analogy of the reversible Markov chains, the paper provides an upper bound of $O(nmD\log n)$ for the expected convergence time to consensus, where $n$ , $m$ and $D$ , denote, respectively, the number of nodes, the number of edges, and the diameter of the network. Moreover, the paper shows that the above upper bound is tight up to a factor of $\log n$ for some simple graphs such as line graph and cycle. Finally, the results are extended to bound the expected convergence time of the underlying dynamics in time-varying networks. Modeling such dynamics as the evolution of a time inhomogeneous Markov chain, the paper derives an upper bound for the expected convergence time of the dynamics using the spectral representation of the networks. This upper bound is significantly better than earlier ones given for different quantized consensus protocols over time-varying graphs.
Urbanization without growth in historical perspective

The world is becoming more and more urbanized at every income level, and there has been a dramatic increase in the number of mega-cities in the developing world. This has led scholars to believe that development and urbanization are not always correlated, either across space or over time. In this paper, we use historical data at both the country level and city level over the five centuries between 1500–2010 to revisit the topic of “urbanization without growth” (Fay and Opal, 2000). In particular, we first establish that, although urbanization and income remain highly correlated within any given year, urbanization is 25–30 percentage points higher in 2010 than in 1500 at every level of income per capita. Second, while historically this shift in urbanization rates was more noticeable at the upper tail of the income distribution, i.e. for richer countries, it is now particularly visible at the lower tail, i.e. for poorer countries. Third, these patterns suggest that different factors may have explained the shift in different periods of time. We use the discussion of these factors as an opportunity to provide a survey of the literature and summarize our knowledge of what drives the urbanization process over time.
Splitting Tax Refunds and Building Savings: An Empirical Test

Families are more likely to save if they can commit to savings before funds are in-hand (and subject to spending temptations). For low- and moderate-income U.S. families, an important savings opportunity arises annually, during income tax season. We study a group of low-income individuals in Tulsa, Okalahoma, who, at the time of tax filing, were encouraged to save parts of their federal refunds. Those who agreed directed a portion of their refund to a savings account, and arranged to have the rest sent to them in the form of a check. Eligible individuals could also open low-cost savings accounts. We document the demand for these services, the characteristics of those who sought to participate, the savings goals of those who participated, the immediate savings generated by the program, and the disposition of savings a few months after receipt. This pilot study suggests that there may be demand among low-income families for a refund-splitting program that supports emergency needs as well as asset building, especially if a basic savings product is available to all at the time of tax filing.
Basic fibroblast growth factor-induced activation of novel CREB kinase during the differentiation of immortalized hippocampal cells.

Growth factors bind to their specific receptors on the responsive cell surface and thereby initiate dramatic changes in the proliferation, differentiation, and survival of their target cells. In the present study we have examined the mechanism by which growth factor-induced signals are propagated to the nucleus, leading to the activation of transcription factor, cis-acting cAMP response element (CRE)-binding protein (CREB), in immortalized hippocampal progenitor cells (H19-7). During the differentiation of H19-7 cells by basic fibroblast growth factor (bFGF) a critical regulatory Ser133 residue of CREB was phosphorylated followed by an increase of CRE-mediated gene transcription. Expression of S133A CREB mutants blocked the differentiation of H19-7 cells by bFGF. Although the kinetics of CREB phosphorylation by EGF was transient, bFGF induced a prolonged pattern of CREB phosphorylation. Interestingly, bFGF-induced CREB phosphorylation and subsequent CRE-mediated gene transcription is not likely to be mediated by any of previously known signaling pathways that lead to phosphorylation of CREB, such as mitogen-activated protein kinases, protein kinase A, protein kinase C, phosphatidylinositol 3-kinase-p70S6K, calcium/calmodulindependent protein kinase, and casein kinase 2. By using in vitro in gel kinase assay the presence of a novel 120-kDa bFGF-inducible CREB kinase was identified. These findings identify a new growth factor-activated signaling pathway that regulates gene expression at the CRE.
Assessment of the aromaticity of borepin rings by spectroscopic, crystallographic and computational methods: a historical overview

This review presents a chronological discussion of the evolution of our conceptual and experimental understanding of aromaticity as pertaining to the borepin ring structure. Borepin is the boron-containing charge-neutral analogue of the carbocyclic tropylium ion, and many molecular variations involving the borepin motif have been synthesized over the past half century. The aromaticity of the borepin system has been probed with ultraviolet–visible (UV–vis), photoluminescence and infrared (IR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, X-ray crystallography and computational analysis. Recently, the focus of borepin-containing compounds has shifted to π-electron materials, building on the foundation of a firm understanding of the physical organic properties of the borepin motif that will allow for electronic fine-tuning toward desired applications. Copyright © 2015 John Wiley & Sons, Ltd.
New Approaches to Password Authenticated Key Exchange Based on RSA

We investigate efficient protocols for password-authenticated key exchange based on the RSA public-key cryptosystem. To date, most of the published protocols for password-authenticated key exchange were based on Diffie-Hellman key exchange. It seems difficult to design efficient password-authenticated key exchange protocols using RSA and other public-key cryptographic techniques. In fact, many of the proposed protocols for password-authenticated key exchange based on RSA have been shown to be insecure; the only one that remains secure is the SNAPI protocol. Unfortunately, the SNAPI protocol has to use a prime public exponent e larger than the RSA modulus n. In this paper, we present a new password-authenticated key exchange protocol, called PEKEP, which allows using both large and small prime numbers as RSA public exponent. Based on number-theoretic techniques, we show that the new protocol is secure against the e-residue attack, a special type of off-line dictionary attack against RSA-based password-authenticated key exchange protocols. We also provide a formal security analysis of PEKEP under the RSA assumption and the random oracle model. On the basis of PEKEP, we present a computationally-efficient key exchange protocol to mitigate the burden on communication entities.
The Neutrino Mass Matrix - New Developments

With the recent experimental advance in our precise knowledge of the neutrino oscillation parameters, the correct form of the 3 x 3 neutrino mass matrix is now approximately known. I discuss how this may be obtained from symmetry principles, using as examples the finite groups A 4 and Z 4, predicting as a result three nearly degenerate Majorana neutrino masses in the 0.2 eV range.
Submillimeter heterodyne spectroscopy and remote sensing of the upper atmosphere

It is noted that remote sensing by submillimeter-wave heterodyne spectroscopy can provide measurements for studying global change and processes in the Earth's atmosphere. The characteristics of stratospheric submillimeter spectra are discussed, and the planned submillimeter Microwave Limb Sounder experiment for the Earth Observing System is briefly considered. >
Conformal Models and Fingerprints of Pseudo-lemniscates

We prove that every meromorphic function on the closure of an analytic Jordan domain that is sufficiently well-behaved on the boundary is conformally equivalent to a rational map whose degree is smallest possible. We also show that the minimality of the degree fails in general without the boundary assumptions. As an application, we generalize a theorem of Ebenfelt, Khavinson, and Shapiro by characterizing fingerprints of polynomial pseudo-lemniscates.
Infrastructure, growth, and inequality : an overview

Academics and policy makers have long considered an adequate supply of infrastructure services to be essential for economic development. This paper reviews recent theoretical and empirical literature on the effects of infrastructure development on growth and income distribution. The theoretical literature has employed a variety of analytical settings regarding the drivers of income growth, the degree to which infrastructure represents a public or a private good, and the extent of market distortions, notably in capital markets. In turn, the empirical literature has used various econometric methodologies on time-series and cross-section macro and microeconomic data to test for the effects of infrastructure development. However, these empirical tests face challenging issues of measurement, identification, and heterogeneity. Overall, the literature finds positive effects of infrastructure development on income growth and, more tentatively, on distributive equity. Still, the precise mechanisms through which these effects accrue, and their full impact on welfare, remain relatively unexplored.
Mechanism of incipient oxidation of bulk chemical vapor deposited Si3N4

X-ray photoelectron spectroscopy was employed, in conjunction with ion bombardment, to analyze the chemical composition profile across thin (less than 50 nm) oxide films on chemically vapor deposited Si3N4. The thermal oxides were grown in dry oxygen at 1100 C on samples with or without native oxide film (formed in room air). The results show that the thermal oxidation product was silicon oxynitride of graded N:O ratio, and that the presence of a native oxide film promotes the formation of a SiO2 crust over the oxynitride. It is proposed that the fundamental mechanism of Si3N4 oxidation is progressive O-for-N substitution in the silicon oxynitride unit tetrahedron, which is best designated SiN(2-x)O(2+x), where x is also an index of depth. The corresponding equation for nonstoichiometric oxidation of Si3N4 describes a bulk (rather than an interface) reaction process, with significant implications for O2 and N2 fluxes and diffusivities.
Using Shortlists to Support Decision Making and Improve Recommender System Performance

In this paper, we study shortlists as an interface component for recommender systems with the dual goal of supporting the user's decision process, as well as improving implicit feedback elicitation for increased recommendation quality. A shortlist is a temporary list of candidates that the user is currently considering, e.g., a list of a few movies the user is currently considering for viewing. From a cognitive perspective, shortlists serve as digital short-term memory where users can off-load the items under consideration -- thereby decreasing their cognitive load. From a machine learning perspective, adding items to the shortlist generates a new implicit feedback signal as a by-product of exploration and decision making which can improve recommendation quality. Shortlisting therefore provides additional data for training recommendation systems without the increases in cognitive load that requesting explicit feedback would incur. We perform an user study with a movie recommendation setup to compare interfaces that offer shortlist support with those that do not. From the user studies we conclude: (i) users make better decisions with a shortlist; (ii) users prefer an interface with shortlist support; and (iii) the additional implicit feedback from sessions with a shortlist improves the quality of recommendations by nearly a factor of two.
Balancing Environmental Protection and Energy Production in the Federal Hydropower Licensing Process

The U.S. Federal Energy Regulatory Commission (FERC) must balance environmental protection of riverine resources with the nation's growing demand for power production every time it issues a hydroelectric license. This paper models the bureaucratic agency's decision-making process in issuing these licenses. Data on nearly 500 hydro-power licenses issued from 1983 to 2005 are utilized. It is discovered that legislative and institutional constraints are, by far, the largest influences on FERC's regulatory decisions, implying that if the current allocation of surface water in the United States is considered inefficient, the most effective way to alter this allocation is by passing new legislation, or by implementing institutional reform at FERC.
An analysis and design method for discrete-time linear systems under nested saturation

The paper considers a discrete time linear system under nested saturation. Nested saturation arises, for example, in systems with actuators subject to both magnitude and rate saturation. A condition is derived in terms of a set of auxiliary feedback gains for determining if a given ellipsoid is contractively invariant. Moreover, this condition is shown to be equivalent to linear matrix inequalities (LMIs) in the actual and auxiliary feedback gains. As a result, the estimation of the domain of attraction for a given set of feedback gains is formulated as an optimization problem with LMI constraints. By viewing the feedback gains as extra free parameters, the optimization problem can be used for controller design.
Pharmacologically relevant intake during chronic, free-choice drinking rhythms in selectively bred high alcohol-preferring mice.

Multiple lines of High Alcohol Preferring (HAP) mice were selectively bred for their intake of 10% ethanol (v/v) during 24-h daily access over a four-week period, with the highest drinking lines exhibiting intakes in excess of 20 g/kg/day. We observed circadian drinking patterns and resulting blood ethanol concentrations in the HAP lines. We also compared the drinking rhythms and corresponding blood ethanol concentrations (BEC) of the highest drinking HAP lines to those of the C57BL/6J (B6) inbred strain. Adult male and female crossed HAP (cHAP), HAP replicate lines 1, 2, 3, and B6 mice had free-choice access to 10% ethanol and water for 3 weeks prior to bi-hourly assessments of intake throughout the dark portion of the light-dark cycle. All HAP lines reached and maintained a rate of alcohol intake above the rate at which HAP1 mice metabolize alcohol, and BECs were consistent with this finding. Further, cHAP and HAP1 mice maintained an excessive level of intake throughout the dark portion of the cycle, accumulating mean BEC levels of 261.5 ± 18.09 and 217.9 ± 25.02 mg/dl, respectively. B6 mice drank comparatively modestly, and did not accumulate high BEC levels (53.63 + 8.15 mg/dl). Free-choice drinking demonstrated by the HAP1 and cHAP lines may provide a unique opportunity for modeling the excessive intake that often occurs in alcohol-dependent individuals, and allow for exploration of predisposing factors for excessive consumption, as well as the development of physiological, behavioral, and toxicological outcomes following alcohol exposure.
On computability of equilibria in markets with production

Even though production is an integral part of the Arrow-Debreu market model, most of the work in theoretical computer science has so far concentrated on markets without production, i.e., the exchange economy. This paper takes a significant step towards understanding computational aspects of markets with production.For markets with separable, piecewise-linear concave (SPLC) utilities and SPLC production, we obtain a linear complementarity problem (LCP) formulation that captures exactly the set of equilibria, and we further give a complementary pivot algorithm for finding an equilibrium. This settles a question asked by Eaves in 1975 [14]. Since this is a path-following algorithm, we obtain a proof of membership of this problem in PPAD, using Todd, 1976. We also obtain an elementary proof of existence of equilibrium (i.e., without using a fixed point theorem), rationality, and odd-ness of the number of equilibria. We further give a proof of PPAD-hardness for this problem and also for its restriction to markets with linear utilities and SPLC production. Experiments show that our algorithm is practical. Also, it is strongly polynomial when the number of goods or the number of agents and firms is constant. This extends the result of Devanur and Kannan (2008) to markets with production.Finally, we show that an LCP-based approach cannot be extended to PLC (non-separable) production, by constructing an example which has only irrational equilibria.
Chandra X-Ray Observatory Study of the Orion Nebula Cluster and BN/KL Region

About 1000 X-ray emitting young pre–main-sequence (PMS) stars distributed in mass from ~0.05 M☉ brown dwarfs to a ~50 M☉ O star are detected in an image of the Orion Nebula obtained with the Advanced CCD Imaging Spectrometer on board the Chandra X-Ray Observatory. This is the richest field of sources ever obtained in X-ray astronomy. Individual X-ray luminosities in the Orion Nebula cluster range from the sensitivity limit of 2 × 10^(28) ergs s^(-1) to ~10^(32) ergs s^(-1). ACIS sources include 85%–90% of V < 20 stars, plus a lower but substantial fraction of deeply embedded stars with extinctions as high as A_V ≃ 60. The relationships between X-ray and other PMS stellar properties suggest that X-ray luminosity of lower-mass PMS stars depends more on mass, and possibly stellar rotation, than on bolometric luminosity, as widely reported. In a subsample of 17 unabsorbed stars with mass ≃ 1 M☉, X-ray luminosities are constant at a high level around L_x ≃ 2 × 10^(30) ergs s^(-1) for the first ≃ 2 Myr while descending the convective Hayashi track, but diverge during the 2–10 Myr phase with X-ray emission plummeting in some stars but remaining high in others. This behavior is consistent with the distribution of X-ray luminosities on the zero-age main sequence and with current theories of their rotational history and magnetic dynamos. The sources in the Becklin-Neugebauer/Kleinman-Low region of massive star formation are discussed in detail. They include both unabsorbed and embedded low-mass members of the Orion Nebula cluster, the luminous infrared Source n, and a class of sources without optical or infrared counterparts that may be new magnetically active embedded PMS stars. Several X-ray sources are also variable radio emitters, an association often seen in magnetically active PMS stars. Faint X-ray emission is seen close to, but apparently not coincident with, the Becklin-Neugebauer object. Its nature is not clear.
Extending space colonization tree modeling for artistic control and environmental interactions

There are a growing number of modeling techniques and algorithms for creating and modifying tree structures, both quickly and realistically. Many of these tools are part of larger software packages used for architecture or landscaping designs. In these tools the tree models are static and come from a library selection. In other areas, such as 3D modeling and design in film and animation, the tree creation tools are more open for artistic creativity and freedom of control. Much research has also been done on growing trees that are sensitive to some environment. That is, growing tree models where genus type, and natural and artificial environment factors are taken into heavy consideration. In this paper, we present an approach that facilitates user creativity while still providing a realistic response to environment factors. Our system adapts the Space Colonization Tree Modeling approach to allow for continued branch addition as well as environmental interaction. Feedback from experienced modelers who participated in a user study revealed that our approach generated the tree skeleton structures they intended and also provided realistic interaction with the environment.
Voices of Teacher Candidates: Positive Changes in Multicultural Attitudes and Knowledge

The author explored changes in teacher candidates' multicultural attitudes and knowledge as well as the factors that contributed positively to those changes. Teacher candidates were followed during their teacher preparation program. Data were collected from 2 questionnaires and 9 interviews. The author used repeated measures analysis and percentages to explore changes in multicultural attitudes and knowledge. She also used percentages to identify factors that the participants believed influenced those changes. Findings suggest that teacher candidates' multicultural attitudes and knowledge changed in a positive direction while the candidates attended a teacher preparation program. Changes seemed to be influenced by fieldwork experiences in culturally/ethnically diverse settings, courses in multicultural and bilingual education, and classmates.
Shrinking binary and planetary orbits by Kozai cycles with tidal friction

At least two arguments suggest that the orbits of a large fraction of binary stars and extrasolar planets shrank by 1-2 orders of magnitude after formation: (1) the physical radius of a star shrinks by a large factor from birth to the main sequence, yet many main-sequence stars have companions orbiting only a few stellar radii away, and (2) in current theories of planet formation, the region within ~0.1 AU of a protostar is too hot and rarefied for a Jupiter-mass planet to form, yet many hot Jupiters are observed at such distances. We investigate orbital shrinkage by the combined effects of secular perturbations from a distant companion star (Kozai oscillations) and tidal friction. We integrate the relevant equations of motion to predict the distribution of orbital elements produced by this process. Binary stars with orbital periods of 0.1-10 days, with a median of ~2 days, are produced from binaries with much longer periods (10 to ~105 days), consistent with observations indicating that most or all short-period binaries have distant companions (tertiaries). We also make two new testable predictions: (1) For periods between 3 and 10 days, the distribution of the mutual inclination between the inner binary and the tertiary orbit should peak strongly near 40? and 140?. (2) Extrasolar planets whose host stars have a distant binary companion may also undergo this process, in which case the orbit of the resulting hot Jupiter will typically be misaligned with the equator of its host star.
Polyvalent pneumococcal polysaccharide vaccines

Summary It has been shown that polyvalent pneumococcal polysaccharide vaccine, now commercially available, is safe, antigenic, and provides protection against pneumonias caused by the pneumococcal serotypes which are present in the vaccine. Early studies also show protection against otitis media caused by these organisms (Makela, 1979). The vaccine is effective in persons with anatomical or functional splenic deficiency but there is a lowered antibody response in immunodepressed patients. Pneumococcal vaccine can be given simultaneously with influenza virus vaccine without significant depression in antibody response to either vaccine and without any increase in reactogenicity. The vaccine contains 14 serotypes that cause approximately 80 per cent of all pneumococcal illnesses, and it shows 80 per cent or greater protective efficacy against pneumonias caused by those serotypes present in the vaccine. Reactions to the vaccine are self-limited and consist generally of mild local and systemic responses. Children of two years of age or older generally respond well to the vaccine; those less than two years of age respond poorly to a majority of the serotypes. It appears that this deficiency may be overcome in part by giving two doses of vaccine at optimally spaced intervals that still remain to be defined. Immunity is expected to last for at least three years at which time booster immunisation might be considered. Reimmunisation at a 12–18 month interval showed no elevation in antibody and there was increased local reaction, apparently due to an ‘Arthus-like' reaction at the site of injection. This may be overcome by reduced dosage on revaccination but no firm recommendations can be formulated at this time.
Differential Harnack Estimates for Time-Dependent Heat Equations with Potentials

In this paper, we prove a differential Harnack inequality for positive solutions of time-dependent heat equations with potentials. We also prove a gradient estimate for the positive solution of the time-dependent heat equation.
The economic instrumentality of work: An examination of the moderating effects of financial requirements and sex on the pay-life satisfaction relationship.

Abstract Congruent with an attempt to better understand the economic instrumentality of work, it was hypothesized that (1) pay satisfaction and life satisfaction are correlated positively; (2) the pay-life satisfaction relationship is moderated by financial requirements such that the relationship is stronger for those with high requirements; and (3) the pay-life satisfaction relationship is jointly moderated by financial requirements and sex such that the relationship is stronger for males with high requirements. Among a sample of managerial and professional workers employed by an insurance company, support for each hypothesis was obtained. The results are discussed in terms of the need to consider further the impact of family configuration and the breadwinner role on workers' reactions to their jobs.
Cooperative Catalyst Effects in Palladium-Mediated Cyanation Reactions of Aryl Halides and Triflates

Substoichiometric quantities of copper or zinc species dramatically improve both conversion rate and efficiency of Pd(0)-catalyzed cyanation reactions. The optimum reaction conditions involve the use of a nitrile solvent, NaCN, and a catalyst system employing the combination of cuprous iodide with tetrakis(triphenylphosphine)palladium(0), [Pd(PPh3)4]. Beneficial effects were observed for the conversion of aryl halides, aryl triflates, and a vinyl bromide to the corresponding nitriles. The process was demonstrated on preparative scale with a broad range of aromatic and heteroaromatic substrates containing diverse functionality. A dual catalytic cycle is proposed to explain the profound influences of the cocatalyst system.
Commotio cordis. The single, most common cause of traumatic death in youth baseball.

• Two cases of blunt chest trauma caused by a baseball are reported, including one death. At least one of these was in consequence of cardiac concussion or commotio cordis, an entity not described in the pediatric literature. Concussion of the heart is a functional injury, in contrast to cardiac contusion or cardiac rupture, which pertains to structural injury. However, a cardiac concussion appears more likely to have immediate, dire consequences than the structural injury of cardiac contusion. Both of the cases presented occurred in the Little League baseball setting. Blunt chest trauma is reported to cause two to three deaths in youth baseball each year. There appears to be an increased pediatric susceptibility to this type of injury. Unfortunately, these cases are quite resistant to resuscitative therapy. Devices and techniques for primary and secondary prevention exist, but have yet to be systematically verified and implemented. ( AJDC. 1991;145:1279-1282)
Optimum Design and Control of Active Constrained Layer Damping

Conventional Passive Constrained Layer Damping (PCLD) treatments with viscoelastic cores are provided with built-in sensing and actuation capabilities to actively control and enhance their vibration damping characteristics. The design parameters and control gains of the resulting Active Constrained Layer Damping (ACLD) treatments are optimally selected, in this paper, for fully-treated beams using rational design procedures. The optimal thickness and shear modulus of the passive visco-elastic core are determined first to maximize the modal damping ratios and minimize the total weight of the damping treatment. The control gains of the ACLD are then selected using optimal control theory to minimize a weighted sum of the vibrational and control energies. The theoretical performance of beams treated with the optimally selected ACLD treatment is determined at different excitation frequencies and operating temperatures. Comparisons are made with the performance of beams treated with optimal PCLD treatments and untreated beams which are controlled only by conventional Active Controllers (AC). The results obtained emphasize the potential of the optimally designed ACLD as an effective means for providing broad-band attenuation capabilities over wide range or operating temperatures as compared to PCLD treatments.
Clouds and chemistry: Ultracool dwarf atmospheric properties from optical and infrared colors

The optical and infrared colors of L and T dwarfs are sensitive to cloud sedimentation and chemical equilibrium processes in their atmospheres. The i'-z' versus J-K color-color diagram provides a window into diverse atmospheric processes mainly because different chemical processes govern each color, and cloud opacity largely affects J-K but not i'-z'. Using theoretical atmosphere models that include for the first time a self-consistent treatment of cloud formation, we present an interpretation of the i'-z' versus J-K color trends of known L and T dwarfs. We find that the i'-z' color is extremely sensitive to chemical equilibrium assumptions; chemical equilibrium models accounting for cloud sedimentation predict redder i'-z' colors—by up to 2 mag—than models that neglect sedimentation. We explore the previously known J-K color trends in which objects first become redder, then bluer with decreasing effective temperature. Only models that include sedimentation of condensates are able to reproduce these trends. We find that the exact track of a cooling brown dwarf in J-K (and i'-z') is very sensitive to the details of clouds, in particular to the efficiency of sedimentation of condensates in its atmosphere. We also find that clouds still affect the strength of the J-, H-, and K-band fluxes of even the coolest T dwarfs. In addition, we predict the locus in the i'-z' versus J-K color-color diagram of brown dwarfs cooler than yet discovered.
An experimental investigation of cusped magnetic field discharge chambers

Several features of a proposed model of ion thruster performance are tested experimentally. The experiment conducted demonstrates the effects of variation in thruster operating parameters on the average plasma ion energy costs and extracted ion fractions of various ring and line cusp discharge chambers. The results indicate that the model correctly predicts the variation in the plasma ion energy cost resulting from changes in: propellant gas, grid transparency to neutral atoms, beam extraction area, and discharge voltage. In addition, the model is shown to be applicable to both ring and line cusp designs. Measurements of the extracted ion fraction indicate that this parameter tends to increase with decreasing discharge voltage and is generally higher for operation with argon as opposed to krypton propellant. Results suggest that to use the proposed thruster performance model as an aid in thruster design the performance may be described in terms of four thruster configuration dependent constants and two operating parameters.
Rent Vouchers and the Price of Low-Income Housing

Since the early 1980s, low-income housing subsidies have increasingly shifted towards vouchers which allow recipients to rent in the private market. By 1993, vouchers subsidized as many households as lived in traditional housing projects, although most low-income households did not receive any subsidies. This study investigates whether this policy has raised rents for unsubsidized poor households, as many analysts predicted when the program was conceived. The main finding is that low-income households in metropolitan areas with more vouchers have experienced faster rent increases than those where vouchers are less abundant. In the 90 biggest metropolitan areas, vouchers have raised rents by 16 percent on average, a large effect consistent with a low supply elasticity in the low quality rental housing market. Considered as a transfer program, this result implies that vouchers have caused a $8.2 billion increase in the total rent paid by low-income non-recipients, while only providing a subsidy of $5.8 billion to recipients, resulting in a net loss of $2.4 billion to low-income households.
Systemic Mastocytosis in the Elderly

"Later onset" of systemic mastocytosis (SM) has been associated with a poorer prognosis. We examined clinical and laboratory findings, associated disorders, and survival in an older mastocytosis population. After receiving Mayo Clinic Institutional Review Board approval, we identified 42 patients aged 70 years and older at the time of diagnosis of SM. Associated disorders, cytogenetic abnormalities, laboratory findings, and survival were recorded. Only 10 patients had no associated hematologic disorder. Single or multiple chromosomal abnormalities, exclusive of the KIT Asp816Val mutation, were detected in eight patients (19%). KIT Asp816Val mutation was present in 14 patients, negative in three, and not tested in 25. Slight to marked bone marrow hypercellularity was observed in 33 patients (79%). Concurrent hematologic abnormalities included chronic myelomonocytic leukemia (n = 7), acute myelocytic leukemia (n = 1), myelodysplastic syndrome (MDS; n = 7), eosinophilia (n = 7), myelofibrosis (n = 1), myeloproliferative disorder (n = 1), multiple myeloma (n = 1), B-cell lymphoma (n = 1), and thrombocytopenia (n = 4). Eight patients had a hematologic disorder that preceded the diagnosis of SM. Tryptase levels were elevated in 38 of 39 patients tested. Survival from the diagnosis of SM was poor for patients with associated thrombocytopenia, leukemias, and MDS. In conclusion, patients with SM diagnosed at age 70 or older have an increased risk of secondary hematologic disorders and abnormal laboratory findings. Cytogenetic abnormalities are common, and survival is short in many SM patients with associated leukemias, MDS, or eosinophilia.