cssi/SciSciGPT-SciSciNet huggingface dataset:
A time-series analysis of unemployment and health. The case of birth outcomes in New York City.

Abstract The paper presents an aggregate time-series analysis of unemployment and infant health that improves on previous work in several ways. First, the data is monthly as opposed to annual. Second, the measure of health, the percentage of low-birthweight births, and the health inputs are rare-specific. Third, because a pregnancy is limited to at most ten months, we can specify a lag length with a greater degree of confidence. We find no cyclical variation in the percentage of low-birthweight births. The results are insensitive to changes in lag length, health inputs, and functional form.
Research and Productivity

We propose an informational theory of how research raises productivity. We model research as a signal on an unknown parameter of a technology. Such a signal teaches the firm how to operate the technology it uses now, or one that it intends to use in the future. The paper deals with two topics. The first is the construction of the firm’s knowledge stock, and the second is the interpretation of existing estimates of the rate of return to basic and applied research.
Present-bias, procrastination and deadlines in a field experiment

Abstract We study procrastination in the context of a field experiment involving students who must exert costly effort to complete certain tasks by a fixed deadline. We document a robust demand for commitment, in the form of self-imposed deadlines. On the other hand, deadlines do not increase completion rates in our experiment. Furthermore, while we find that present-bias is widespread in the sample, and present-biased students procrastinate in single task treatments, we find that they successfully manage to self-control in repeated task treatments. Finally, we find evidence that students do not set deadlines optimally and that deadlines may hurt them, due to various behavioral components of students' anticipation formation mechanisms; specifically, partial naivete at the deadline setting stage and over-confidence about the ability to complete the task and to persevere on a task after a failed attempt.
Spinors, Inflation, and Non-Singular Cyclic Cosmologies

We consider toy cosmological models in which a classical, homogeneous, spinor field provides a dominant or sub-dominant contribution to the energy-momentum tensor of a flat Friedmann-Robertson-Walker universe. We find that, if such a field were to exist, appropriate choices of the spinor self-interaction would generate a rich variety of behaviors, quite different from their widely studied scalar field counterparts. We first discuss solutions that incorporate a stage of cosmic inflation and estimate the primordial spectrum of density perturbations seeded during such a stage. Inflation driven by a spinor field turns out to be unappealing as it leads to a blue spectrum of perturbations and requires considerable fine-tuning of parameters. We next find that, for simple, quartic spinor self-interactions, non-singular cyclic cosmologies exist with reasonable parameter choices. These solutions might eventually be incorporated into a successful past- and future-eternal cosmological model free of singularities. In an Appendix, we discuss the classical treatment of spinors and argue that certain quantum systems might be approximated in terms of such fields.
Born with a silver spoon : inequality in educational achievement across the world

This paper assesses inequality of opportunity in educational achievement using the Human Opportunity Index methodology on data from the Programme for International Student Assessment. The findings suggest that there are large inequalities in learning outcomes as measured by demonstrated proficiency in Programme for International Student Assessment test scores in math, reading, and science. Differences in wealth, parental education, and area of residence explain a bulk of this inequality in most of the countries in the sample. Consistent with what has been documented previously in the literature, the paper also finds a strong and stable correlation between inequality of opportunity and public spending on school education. An exploration of the changes in inequality of opportunity between the 2009 and 2012 rounds of the Programme for International Student Assessment, using parametric and nonparametric techniques, suggests that there has been little progress.
Hedging-Effectiveness of Milk Futures Using Value-At-Risk Procedures

Summary and Conclusions Milk price risk was defined as the deviation of the actual milk price from the expected milk price, and uniform hedges triggered at $11 per cwt or $12 per cwt were simulated using constant and time-varying minimum variance hedge ratios. The results indicated that uniform futures hedging has the potential to reduce substantially the VaR of milk producers’ mailbox price in Wisconsin, the Northeast, and to a smaller extent in California. Ultimately the relative decrease in cash VaR with uniform hedging depends on producer preferences toward risk. A certain VaR reduction may be sufficient to justify hedging for some producers but not others. For a dairy producer, a reduction in the VaR implies that the size of potential adverse price movement has diminished. Most of the VaR statistics computed at the 90% and 95% confidence intervals suggest that adverse large changes in mailbox price risk are lower when a uniform hedging strategy is performed than when a cash-only strategy is adopted. In this article, the hedging effectiveness measure with VaR seems to be more sensitive to the hedge length and the price that the producers choose to lock in than to the assumption regarding the hedge ratio. Consistent with most studies using alternative VaR methodologies, the results indicated some disparity in the VaR of milk mailbox price depending on whether the parametric method, the historical simulation method, or the Monte Carlo simulation method was used. The sensitivity of VaR estimates to the method used for its calculation is reported in Manfredo and Leuthold (1998), and in Mahoney (1995).
Analysis of stratified flow mixing

The Creare one-fifth-scale Phase II experiments, which model fluid and thermal mixing of relatively cold high-pressure injection water into a cold leg of a full-scale pressurized water reactor havi...
Observing the First Stars and Black Holes

The high sensitivity of JWST will open a new window on the end of the cosmological dark ages. Small stellar clusters, with a stellar mass of several × 106 M⊙, and low-mass black holes (BHs), with a mass of several $× 105 M⊙ should be directly detectable out to redshift z = 10, and individual supernovae (SNe) and gamma ray burst GRB afterglows are bright enough to be visible beyond this redshift. Dense primordial gas, in the process of collapsing from large scales to form protogalaxies, may also be possible to image through diffuse recombination line emission, possibly even before stars or BHs are formed. In this article, I discuss the key physical processes that are expected to have determined the sizes of the first star–clusters and black holes, and the prospect of studying these objects by direct detections with JWST and with other instruments. The direct light emitted by the very first stellar clusters and intermediate-mass black holes at z > 10 will likely fall below JWST’s detection threshold. However, JWST could reveal a decline at the faint-end of the high-redshift luminosity function, and thereby shed light on radiative and other feedback effects that operate at these early epochs. JWST will also have the sensitivity to detect individual SNe from beyond z = 10. In a dedicated survey lasting for several weeks, thousands of SNe could be detected at z > 6, with a redshift distribution extending to the formation of the very first stars at z ≳ 15. Using these SNe as tracers may be the only method to map out the earliest stages of the cosmic star–formation history. Finally, we point out that studying the earliest objects at high redshift will also offer a new window on the primordial power spectrum, on ∼100 times smaller scales than probed by current large-scale structure data.
Uniqueness of the 2-universality Criterion

En Kim, Kim, and Oh gave a minimal criterion for the 2-universality of positivedefinite integer-matrix quadratic forms. We show that this 2-universality criterion is unique in the sense of the uniqueness of the Conway-Schneeberger Fifteen Theorem.
Adaptive Cut Generation Algorithm for Improved Linear Programming Decoding of Binary Linear Codes

Linear programming (LP) decoding approximates maximum-likelihood (ML) decoding of a linear block code by relaxing the equivalent ML integer programming (IP) problem into a more easily solved LP problem. The LP problem is defined by a set of box constraints together with a set of linear inequalities called “parity inequalities” that are derived from the constraints represented by the rows of a parity-check matrix of the code and can be added iteratively and adaptively. In this paper, we first derive a new necessary condition and a new sufficient condition for a violated parity inequality constraint, or “cut,” at a point in the unit hypercube. Then, we propose a new and effective algorithm to generate parity inequalities derived from certain additional redundant parity check (RPC) constraints that can eliminate pseudocodewords produced by the LP decoder, often significantly improving the decoder error-rate performance. The cut-generating algorithm is based upon a specific transformation of an initial parity-check matrix of the linear block code. We also design two variations of the proposed decoder to make it more efficient when it is combined with the new cut-generating algorithm. Simulation results for several low-density parity-check (LDPC) codes demonstrate that the proposed decoding algorithms significantly narrow the performance gap between LP decoding and ML decoding.
PATTERN SPEEDS OF SPIRAL GALAXIES USING THE TREMAINE-WEINBERG METHOD

Long-lasting spiral structure in galaxies is established when density waves form a pattern that rotates at a constant angular frequency Ωp, the pattern speed. This quantity, critical to understanding spiral structure, galaxy evolution, and the connection, if any, between bars and spirals in galaxies, is not directly measurable. Most determinations of pattern speeds have relied on identifying morphological features at certain radii as resonances, but this depends significantly on knowledge of the behavior of stars and gas at these resonances. The Tremaine-Weinberg (TW) method allows for the determination of pattern speeds based on kinematic observations in a way completely independent of resonance identification, or theories of spiral structure, relying on the identification of a tracer that obeys the continuity equation as it orbits through the pattern. This work expands on previous studies of the TW method applied to galaxies with molecularor HI-dominated ISMs. In galaxies where the ISM is found to be dominated by one phase, it is assumed that this component satisfies the continuity requirement; for galaxies with H2 dominated ISMs, for instance, the TW method has successfully been applied using CO(1-0) emission as a tracer for the molecular gas surface density (Rand & Wallin 2004).
Taylor Rules and the Euro

This paper uses real-time data to analyze whether the variables that normally enter central banks’ interest-ratesetting rules, which we call Taylor rule fundamentals, can provide evidence of out-of-sample predictability for the United States Dollar/Euro exchange rate from the inception of the Euro in 1999 to the end of 2007. The major result of the paper is that the null hypothesis of no predictability can be rejected against an alternative hypothesis of predictability with Taylor rule fundamentals for a wide variety of specifications that include inflation and a measure of real economic activity in the forecasting regression. We also present less formal evidence that, with real-time data, the Taylor rule provides a better description of ECB than of Fed policy during this period. While the evidence of predictability is only found for specifications that do not include the real exchange rate in the forecasting regression, the results are robust to whether or not the coefficients on inflation and the real economic activity measure are constrained to be the same for the U.S. and the Euro Area and to whether or not there is interest rate smoothing. The evidence of predictability is stronger for realtime than for revised data, about the same with inflation forecasts as with inflation rates, and weakens if output gap growth is included in the forecasting regression. Bad news about inflation and good news about real economic activity both lead to out-of-sample predictability through forecasted exchange rate appreciation.
Effects of job instruction on maintenance task performance

Written documentation has been implemented in aviation maintenance errors so that documentation becomes an important safety issue. A restricted technical language for job instruction, Simplified English was tested to determine whether or not it reduced error rate in a maintenance task. Experienced and inexperienced participants performed on easy and a difficult maintenance task on a small internal combustion engine using three languages of job instruction: original, Simplified English and a hybrid. Task errors were reduced with Simplified English but increased with the hybrid version. While the easy task and the experienced participants made fewer errors, neither participant expertise nor task difficulty interacted with instruction language. Hence, Simplified English can be recommended, but hybrid instructions should be avoided.
Incomplete contracts and the theory of the firm

"The Nature of the Firm" (together with Coase's later paper, "The Problem of Social Cost") has had an enormous influence on the development of research in the theory of organization, even if for a long time it was, in Coase's words, "much cited and little used." The situation has changed in the last ten to fifteen years, however, with the publication of a number of contributions which have refined and extended Coase's ideas about the firm. My plan in this paper is to reflect on recent developments and to offer a perspective on where the field stands and also where it may be going. I will begin with a brief summary of the main ideas and issues as they have grown out of Coase's work.' I will then discuss how the firm as an institution can be thought of as arising from the incompleteness of contracts and the need to allocate residual control rights. Finally, I will return to a comparison of this view of the firm with others that have been advanced in the literature.
Missive: fast application launch from an untrusted buffer cache

The Embassies system [18] turns the web browser model inside out: the client is ultra-minimal, and hence strongly isolates pages and apps; every app carries its own libraries and provides itself OS-like services. A typical Embassies app is 100 MiB of binary code. We have found that the first reaction most people have upon learning of this design is: how can big apps start quickly in such a harsh, mutually-untrusting environment? The key is the observation that, with appropriate system organization, the performance enhancements of a shared buffer cache can be supplied by an untrusted component. The benefits of sharing depend on availability of commonality; this paper measures a hundred diverse applications to show that applications indeed exhibit sufficient commonality to enable fast start, reducing startup data from 64MiB to 1MiB. Exploiting that commonality requires careful packaging and appropriate application of conventional deduplication and incremental start techniques. These enable an untrusted client-side cache to rapidly assemble an app image and transfer it--via IP--to the bootstrapping process. The result is proof that big apps really can start in a few hundred milliseconds from a shared but untrusted buffer cache.
A Survey on Cognitive Radio Networks

The limitation of the spectrum bands is a major bottleneck for the development of next generation wireless networks. Cognitive Radio (CR) aims at improving the spectrum utilization by taking advantage of licensed but currently unused spectrum. CR has broad applications including dynamic spectrum access and interference management, which will largely impact the next generation of wireless devices and networks. In this paper, we conducted a survey on CR networks from various aspects such as waveform, spectrum management and sensing, testbeds, performance evaluations and etc.
A Scenario-Based Approach for the Air Traffic Flow Management Problem with Stochastic Capacities

In this paper, we investigate the strategic stochastic air traffic flow management problem which seeks to balance airspace capacity and demand under weather disruptions. The goal is to reduce the need for myopic tactical decisions that do not account for probabilistic knowledge about the NAS near-future states. We present and discuss a scenario-based modeling approach based on a time-space stochastic process to depict weather disruption occurrences in the NAS. A solution framework is also proposed along with a distributed implementation aimed at overcoming scalability problems. Issues related to this implementation are also discussed.
Semantic Optimization of Preference Queries

Preference queries are relational algebra or SQL queries that contain occurrences of the winnow operator (find the most preferred tuples in a given relation). We present here a number of semantic optimization techniques applicable to preference queries. The techniques make it possible to remove redundant occurrences of the winnow operator and to apply a more efficient algorithm for the computation of winnow. We also study the propagation of integrity constraints in the result of the winnow. We have identified necessary and sufficient conditions for the applicability of our techniques, and formulated those conditions as constraint satisfiability problems.
CONTRACTIVE PROJECTIONS AND OPERATOR SPACES

Parallel to the study of finite-dimensional Banach spaces, there is a growing interest in the corresponding local theory of operator spaces. We define a family of Hilbertian operator spaces H k n, 1 < k < n, generalizing the row and column Hilbert spaces R n and C n , and we show that an atomic subspace X C B(H) that is the range of a contractive projection on B(H) is isometrically completely contractive to an ∞-sum of the H k n and Cartan factors of types 1 to 4. In particular, for finite-dimensional X, this answers a question posed by Oikhberg and Rosenthal. Explicit in the proof is a classification up to complete isometry of atomic w*-closed JW*-triples without an infinite-dimensional rank 1 w*-closed ideal.
Temporal Stability of Molecular Diversity Measures in Natural Populations of Drosophila pseudoobscura and Drosophila persimilis

Many molecular ecological and evolutionary studies sample wild populations at a single point in time, but that data represents genetic variation from a potentially unrepresentative snapshot in time. Variation across time in genetic parameters may occur quickly in species that produce multiple generations of offspring per year. Here, we compare genetic diversity in wild caught populations of Drosophila persimilis and Drosophila pseudoobscura collected 16 years apart at the same time of year and same site at 4 X-linked and 2 mitochondrial loci to assess genetic stability. We found no major changes in nucleotide diversity in either species, but we observed a drastic shift in Tajima’s D between D. pseudoobscura timepoints at 1 locus associated with increased abundance of a set of related haplotypes. Our data also suggests that D. persimilis may have recently accelerated its demographic expansion. While the changes we observed were modest, this study reinforces the importance of considering potential temporal variation in genetic parameters within single populations over short evolutionary timescales.
Sustainable and smart cities

This paper explores the challenges and opportunities that government officials face in designing coherent 'rules of the game' for achieving urban sustainability during times of growth. Sustainability is judged by three criteria. The first involves elements of day-to-day quality of life, such as having clean air and water and green space. The provision of these public goods has direct effects on the urban public's health and productivity. The second focuses on the city's greenhouse gas emissions. Developing cities are investing in new infrastructure, from highways and public transit systems to electricity generation and transmission. They are building water treatment, water delivery, and sewage disposal systems. Residents of these cities are simultaneously making key decisions about where they live and work and whether to buy such energy-consuming durables as private vehicles and home air-conditioning units. Given the long-lived durability of the capital stock, short-term decisions will have long-term effects on the city's carbon footprint. The third criterion is a city's resilience to natural disasters and extreme weather events. This subsection focuses on how the urban poor can be better equipped to adapt to the anticipated challenges of climate change.
Characterization of the effects of phorbol esters on rat mast cell secretion.

When applied to the skin, phorbol esters (PEs) elicit signs of acute inflammation, suggesting they may induce the release of mediators from mast cells. Therefore, we have studied the effects of PEs on purified rat peritoneal and thoracic mast cells both alone and in conjunction with the calcium ionophore, A23187, and various other secretagogues that interact with immunoglobulin E (e.g., anti-IgE and Con A) or other cell surface receptors, e.g., somatostatin and compd 48/80. PEs alone caused little or no release of histamine. However, the PE 12-O-tetradecanoylphorbol-13-acetate (TPA, 10 ng/ml) tremendously potentiated release induced by the calcium ionophore A23187, reducing the EC50 for A23187 from 832 ng/ml to 56 ng/ml. In the presence of suboptimal A23187 (50 ng/ml), only active tumor promoting PEs elicited histamine release. The EC50 values of the various active PEs were: TPA 5 ng/ml; 4 beta-PDD, 83 ng/ml; and 4-O-methyl-TPA, 807 ng/ml, with maximal histamine release ranging from 54 to 80%. TPA synergistically enhanced stimulation of histamine release by anti-IgE and Con A over the entire concentration-response range. In contrast, this synergism was absent when cells were stimulated with somatostatin and compd 48/80. Phorbol esters may act by increasing the activity of a calcium/phospholipid-dependent protein kinase (Ca/PL-PK). Mast cells do have Ca/PL-PK activity, and TPA in the presence of suboptimal A23187 induces protein phosphorylation comparable with other secretagogues. These results suggest that in the purified mast cell, PE-induced mediator release increases the sensitivity of release mechanisms for calcium, acts syngergistically with secretagogues interacting with IgE, and as suggested from structure-activity relationships, occurs via a specific mechanism of action perhaps involving the Ca/PL-PK.
Resident-generated versus instructor-generated cases in ethics and professionalism training.

Background The emphasis on ethics and professionalism in medical education continues to increase. Indeed, in the United States the ACGME will require residency programs to include professionalism training in all curricula by 2007. Most courses focus on cases generated by the course instructors rather than on cases generated by the trainees. To date, however, there has been no assessment of the utility of these two case discussion formats. In order to determine the utility of instructor-generated cases (IGCs) versus resident-generated cases (RGCs) in ethics and professionalism training, the author developed an innovative course that included both case formats. The IGCs were landmark cases and cases from the experience of the course instructors, while the RGCs were selected by the residents themselves. Residents were then surveyed to assess the strengths and weaknesses of each format.
The Optimal Combination of Corruption Reforms: Is a Comprehensive Approach a Good Idea?

The earlier work on corruption reform often argues that a broader set of reforms be implemented. The main purpose of the paper is to examine the validity of this argument by formalizing the analysis of the interactions of procurement reforms. The model not only supports well-known interaction effects but also shows a new interaction effect: even if two reforms are substitute, they may be complementary if combined further with another reform. It also shows that it is optimal to carry out a reform alone in certain conditions although it is optimal to combine all reforms in other conditions. More specifically, we examine the single and combination effects of different kinds of possible reform policies: delegation (delegating authority on contracting with the firm to the agency), administrative reforms (improving the agency's monitoring ability), incentive reforms (introducing incentive contracts with the agency) and legal reforms (enhancing legal systems). The following is our results: i) Incentive reforms are anti-corruption policies while administrative reforms and delegation are corruption-accommodating policies, if they are implemented singly. ii) Incentive reforms are complementary to delegation but substitute with administrative reforms. iii) The substitution effect between incentive and administrative reforms disappears if they are further combined with delegation. It follows that if delegation is not costly to implement, it is optimal to combine all reform policies. On the other hand, if delegation is too costly to implement and administrative reforms are not costly, it is optimal to implement them singly. This paper has some implications for the optimal sequence of reforms. It can also account for the persistence and deepening of corruption in some societies over time even if those societies continue to implement optimal reform policy (combination).
A composite genome approach to identify phylogenetically informative data from next-generation sequencing

Improvements in sequencing technology now allow easy acquisition of large datasets; however, analyzing these data for phylogenetics can be challenging. We have developed a novel method to rapidly obtain homologous genomic data for phylogenetics directly from next-generation sequencing reads without the use of a reference genome. This software, called SISRS, avoids the time consuming steps of de novo whole genome assembly, multiple genome alignment, and annotation. For simulations SISRS is able to identify large numbers of loci containing variable sites with phylogenetic signal. For genomic data from apes, SISRS identified thousands of variable sites, from which we produced an accurate phylogeny. Finally, we used SISRS to identify phylogenetic markers that we used to estimate the phylogeny of placental mammals. We recovered eight phylogenies that resolved the basal relationships among mammals using datasets with different levels of missing data. The three alternate resolutions of the basal relationships are consistent with the major hypotheses for the relationships among mammals, all of which have been supported previously by different molecular datasets. SISRS has the potential to transform phylogenetic research. This method eliminates the need for expensive marker development in many studies by using whole genome shotgun sequence data directly. SISRS is open source and freely available at https://github.com/rachelss/SISRS/releases .
Systemic and Idiosyncratic Sovereign Debt Crises

The theoretical literature on sovereign defaults has focused on adverse shocks to debtors’ economies, suggesting that defaults are of an idiosyncratic nature. Still, sovereign debt crises are also of a systemic nature, clustered around panics in the financial center such as the European Sovereign Debt Crisis in the aftermath of the U.S. Subprime Crisis in 2008. Crises in the financial centers are rare disasters and thus, their effects on the periphery can only be captured by examining long episodes. This paper examines sovereign defaults from 1820 to the Great Depression, with a focus on Latin America. We find that 63% of the crises are of a systemic nature. These crises are different. Both the international collapse of liquidity and the growth slowdown in the financial centers are at their core. These global shocks trigger longer default spells and larger investors’ losses.
CORL: a continuous-state offset-dynamics reinforcement learner

Continuous state spaces and stochastic, switching dynamics characterize a number of rich, real-world domains, such as robot navigation across varying terrain. We describe a reinforcement-learning algorithm for learning in these domains and prove for certain environments the algorithm is probably approximately correct with a sample complexity that scales polynomially with the state-space dimension. Unfortunately, no optimal planning techniques exist in general for such problems; instead we use fitted value iteration to solve the learned MDP, and include the error due to approximate planning in our bounds. Finally, we report an experiment using a robotic car driving over varying terrain to demonstrate that these dynamics representations adequately capture real-world dynamics and that our algorithm can be used to efficiently solve such problems.
Ferritin: At the Crossroads of Iron and Oxygen Metabolism

Iron and oxygen are central to terrestrial life. Aqueous iron and oxygen chemistry will produce a ferric ion trillions of times less soluble than cell iron concentrations, along with radical forms of oxygen that are toxic. In the physiological environment, many proteins have evolved to transport iron or modulate the redox chemistry of iron that transforms oxygen in useful biochemical reactions. Only one protein, ferritin, evolved to concentrate iron to levels needed in aerobic metabolism. Reversible formation and dissolution of a solid nanomineral-hydrated, iron oxide is the main function of ferritin, which additionally detoxifies excess iron and possibly dioxygen and reactive oxygen. Ferritin is a large multifunctional, multisubunit protein with eight Fe transport pores, 12 mineral nucleation sites and up to 24 oxidase sites that produce mineral precursors from ferrous iron and oxygen. Regulation of ferritin synthesis in animals uses both DNA and mRNA controls and genes encoding two types of related subunits with: 1) catalytically active (H) or 2) inactive (L) oxidase sites. Ferritin with varying H/L ratios is related to cell-specific iron and oxygen homeostasis. H-ferritin oxidase activity accelerates rates of iron mineralization in ferritins and, in animals, ferritin produces H(2)O(2) as a byproduct. Properties of ferritin mRNA and ferritin protein pore structure are new targets for manipulating iron homeostasis. Recent observations of the high bioavailability of iron in soybean ferritin and efficient utilization of soybean and ferritin iron by iron-deficient animals, and of soybean iron by humans with borderline deficiency, indicate a role for ferritin in managing global iron deficiency in humans.
Microwave spectra, quadrupole coupling constants, and structure of germyl bromide

The microwave spectra from 26.5 to 39.0 GHz of 74GeH2D79Br, 74GeH2D81Br, 74GeHD2 79Br, 74GeHD2 81Br, 74GeD3 79Br, and 74GeD3 81Br have been measured and assigned. From these data, along with the data obtained earlier for the ’’light’’ compound, the rs structural parameters were determined to be r(Ge–H) = 1.527±0.001 A, r(Ge–Br) = 2.297±0.001 A, and ∢HGeBr = 106.3±0.1 °. From a diagnostic least‐squares adjustment to fit 16 rotational constants, the following r0 structural parameters were obtained: r(Ge–H) = 1.526±0.002 A, r(Ge–Br) = 2.299±0.001 A, and ∢HGeBr = 106.2±0.1 °. The centrifugal distortion and quadrupolar coupling constants have been obtained and compared to those previously reported. The results are compared to similar quantities in related molecules.
Abundances of Baade’s Window Giants from Keck HIRES Spectra. II. The Alpha and Light Odd Elements*

We report detailed abundances of O, Na, Mg, Al, Si, Ca, and Ti—elements produced by massive stars—for 27 red giants toward the Galactic bulge in Baade's window. These species are overabundant in the bulge relative to the disk, consistent with enhancement by Type II SN ejecta. [Mg/Fe] = +0.3 dex over the full range of [Fe/H], while O, Si, Ca, and Ti are elevated but follow more disklike trends. We propose that the decline in [O/Fe] is due to metallicity-dependent oxygen yields from massive stars, perhaps connected with the Wolf-Rayet phenomenon. The elements Si, Ca, and Ti, believed to be produced during explosive nucleosynthesis, possess identical trends with [Fe/H]. We attribute the decline of these elements to metallicity-dependent yields in Type II SNe. The trend of [Al/Fe] is found to vary strikingly with environment; the range from the Sgr dwarf to the bulge is 0.7 dex. The disjoint composition of the thick/thin disk and bulge stars is inconsistent with models in which the bulge formed from the thickening of the disk, while the elevated alpha elements are consistent with a rapid bulge formation timescale. The starkly smaller scatter of [SiCaTi/Fe] with [Fe/H] in the bulge compared with the halo is consistent with the expectation that the bulge should have efficiently mixed. The metal-poor bulge [SiCaTi/Fe] ratios are higher than ~80% of the halo; the bulge could not have formed from gas with the present-day halo composition.
Dilepton production in proton-nucleus and nucleus-nucleus collisions at SPS energies

Abstract Dilepton production in proton- and nucleus-induced reactions is studied in the relativistic transport model using initial conditions determined by the string dynamics from RQMD. It is found that both the CERES and HELIOS-3 data for dilepton spectra in proton-nucleus reactions can be well described by the ‘conventional’ mechanism of Dalitz decay and direct vector meson decay. However, to provide a quantitative explanation of the observed dilepton spectra in central S+Au and S+W collisions requires contributions other than these direct decays. Introducing a decrease of vector meson masses in hot and dense medium, we find that these heavy-ion data can also be satisfactorily explained. This agrees with our earlier conclusions based on a fire-cylinder model. We also give predictions for Pb+Au collisions at 160 GeV/nucleon using current CERES mass resolution and acceptance.
SOME COMMENTS ON SSC PHYSICS

This talk discusses some topics of current interest with regard to SSC physics. Uncertainties in rate estimates are discussed as is the status of proposals to search for the Higgs boson. 36 references, 13 figures.
Privacy in the global e-village

Embed responsibility for privacy into radio-frequency identification tags and other information technology designed to network the physical world.
A Method for Determining the Physical Properties of the Coldest Known Brown Dwarfs

We present a method for measuring the physical parameters of the coldest T-type brown dwarfs using lowresolution near-infrared spectra. By comparing H_(2)O and H_2-sensitive spectral ratios between empirical data and theoretical atmosphere models, and calibrating these ratios to measurements for the well-characterized 2–5 Gyr companion brown dwarf Gliese 570D, we derive estimates of the effective temperatures and surface gravities for 13 mid- and late-type field T dwarfs. We also deduce the first quantitative estimate of subsolar metallicity for the peculiar T dwarf 2MASS 0937+2931. Derived temperatures are consistent with prior estimates based on parallax and bolometric luminosity measurements, and examination of possible systematic effects indicate that the results are robust. Two recently discovered late-type T dwarfs, 2MASS 09392448 and 2MASS 11142618, both appear to be ≳50 K cooler than the latest type T dwarf, 2MASS 04150935, and are potentially the coldest and least luminous brown dwarfs currently known. We find that, in general, higher surface gravity T dwarfs have lower effective temperatures and luminosities for a given spectral type, explaining previously observed scatter in the T_(eff) /spectral type relation for these objects. Masses, radii, and ages are estimated for the T dwarfs in our sample using the evolutionary models of Burrows et al.; we also determine masses and radii independently for eight T dwarfs with measured luminosities. These two determinations are largely consistent, lending support to the validity of evolutionary models at late ages. Our method is well suited to large samples of faint brown dwarfs and can ultimately be used to directly measure the substellar mass function and formation history in the Galaxy.
Oxyfunctionalization of (5β)-Bile Acids by Dimethyldioxirane: Hydroxylation at C-5, C-14, and C-17

Abstract Dimethyldioxirane in chloroform solution is an efficient reagent for the tertiary hydroxylation of a series of methyl ester peracetate (5β)-bile acid derivatives. 5β-Hydroxylation was observed in all cases, but the presence of a 7-acetyloxy substituent reduced reactivity of the 5β position allowing competitive 14α- and 17α-functionalization subject to steric and electronic constraints.
Postbuckling failure of composite plates with holes

This paper summarizes a study focused on understanding the failure mechanisms present in a plate with a centrally located circular hole loaded inplane into the postbuckling range of deflections. The study was numerical and experimental in nature and had as a goal the a priori prediction of failure using existing failure data from several sources, together with a stress analysis. The maximum stress failure criterion was used to predict failure and both intra- and interlaminar stresses were considered. Four laminates were considered. The phenomenon of modal interaction, or the jumping from one deformed configuration to another, is discussed. With this jumping, the plate configuration may change from one half-wave in the loading direction to two half-waves in the loading direction. The study concludes that the failure in (+/-45/0/90)2s and (+/-45/2(2))2s laminates is due to fiber compression failure and is predictable. The failure load is, for the most part, independent of response configuration. The (+/-45/0/(6))s laminate fails due to interlaminar shear along the simple support, while the response and failure of the (+/-45)4s laminate is governed to a large degree by material nonlinearities and progressive failure.
Buckling of Oil Storage Tanks in SPPL Tank Farm During the 1979 Imperial Valley Earthquake

An oil storage tank that suffered damage during the 1979 Imperial Valley earthquake is studied using a laboratory model. The tank is unanchored and includes a floating roof. The tank is subjected to a single horizontal axis base excitation. Buckling is studied under both harmonic and simulated earthquake base motion. The model buckling results are in reasonable agreement with the field observations. It was also found that the floating roof has no effect on the buckling behavior. Comparison with the API design provisions shows that the empirical model used as the basis of the code for both tip-over and bucking have little resemblance to the actual tank behavior.
$\ell^2$-homology and planar graphs

In his 1930 paper, Kuratowksi categorized planar graphs, proving that a finite graph $\Gamma$ is planar if and only if it does not contain a subgraph that is homeomorphic to $K_5$, the complete graph on 5 vertices, or $K_{3,3}$, the complete bipartite graph on six vertices. In their 2001 paper, Davis and Okun point out that the $K_{3,3}$ graph can be understood as the nerve of a right-angled Coxeter system and prove that this graph is not planar using results from $\ell^2$-homology. In this paper, we employ a similar method proving $K_5$ is not planar.
Algebraic Stein Varieties

It is well-known that the associated analytic space of an affine variety defined over $\mathbb{C}$ is Stein but the converse is not true, that is, an algebraic Stein variety is not necessarily affine. In this paper, we give sufficient and necessary conditions for an algebraic Stein variety to be affine. One of our results is that an irreducible quasi-projective variety $Y$ defined over $\mathbb{C}$ with dimension $d$ ($d\geq 1$) is affine if and only if $Y$ is Stein, $H^i(Y, {\mathcal{O}}_Y )=0$ for all $i>0$ and $\kappa(D, X)= d$ (i.e., $D$ is a big divisor), where $X$ is a projective variety containing $Y$ and $D$ is an effective divisor with support $X-Y$. If $Y$ is algebraic Stein but not affine, we also discuss the possible transcendental degree of the nonconstant regular functions on $Y$. We prove that $Y$ cannot have $d-1$ algebraically independent nonconstant regular functions. The interesting phenomenon is that the transcendental degree can be even if the dimension of $Y$ is even and the degree can be odd if the dimension of $Y$ is odd.
Maturation-stimulating effect of brain extract and dibutyryl cyclic AMP on dissociated embryonic brain cells in culture☆

Abstract Extracts from adult rat brains contain a macromolecular factor capable of transforming dissociated embryonic rat brain cells in a monolayer culture. The factor simulates the activity of dibutyryl cyclic AMP but is not identical with either cyclic AMP or prostaglandin.
Flight Effects on the Far-Field Noise of a Heated Supersonic Jet

The influence of forward flight on the far-field noise of an underexpanded heated supersonic jet has been studied experimentally with a 12.5-cm-diam convergent nozzle operated in the NASA Ames Research Center 12.2 x 24.4 m (40 x 80 ft) wind tunnel. The nozzle was operated at nozzle pressure ratios up to 4.5 and stagnation temperature ratios from 2.45 to 3.45. The resulting velocity (based on fully expanded condition) range is from 586 to 858 m/s. The freestream Mach number was varied from 0 to 0.32. Far-field narrow band spectra were obtained at angles (measured from the inlet axis) covering a range from 30 to 155 deg. A small amplification of the overall sound-pressure level (2 dB) due to forward flight is observed in the forward quadrant. The mixing noise reduction in the aft quadrant due to forward flight is much smaller than that observed in corresponding cold jets.
Robust transmission of non-Gaussian entanglement over optical fibers

We show how the entanglement in a wide range of continuous variable non-Gaussian states can be preserved against decoherence for long-range quantum communication through an optical fiber. We apply protection via decoherence-free subspaces and quantum dynamical decoupling to this end. The latter is implemented by inserting phase shifters at regular intervals {delta} inside the fiber, where {delta} is roughly the ratio of the speed of light in the fiber to the bath high-frequency cutoff. Detailed estimates of relevant parameters are provided using the boson-boson model of system-bath interaction for silica fibers and {delta} is found to be on the order of a millimeter.
Implementation prototypes in the development of programming language features

This paper describes the experiences of the authors in the application of prototyping techniques to the development of programming languages with "advanced" features such as coroutines and abstract data types. The essence of the approach described here is the careful extension of a suitable base language (Pascal was used in all the experiments described here) by one new facility at a time and the production of a prototype implementation of the new language by modifying an existing implementation of the base language. Criteria for choosing a base language, the central role of formal semantic models in the approach and alternative strategies for producing a new prototype implementation from an existing one are all discussed in some detail.
Interval bounds on the solutions of semi-explicit index-one DAEs. Part 2: computation

This article presents two methods for computing interval bounds on the solutions of nonlinear, semi-explicit, index-one differential-algebraic equations (DAEs). Part 1 presents theoretical developments, while Part 2 discusses implementation and numerical examples. The primary theoretical contributions are (1) an interval inclusion test for existence and uniqueness of a solution, and (2) sufficient conditions, in terms of differential inequalities, for two functions to describe componentwise upper and lower bounds on this solution, point-wise in the independent variable. The first proposed method applies these results sequentially in a two-phase algorithm analogous to validated integration methods for ordinary differential equations (ODEs). The second method unifies these steps to characterize bounds as the solutions of an auxiliary system of DAEs. Efficient implementations of both are described using interval computations and demonstrated on numerical examples.
Renal Artery Dissection Causing Renal Infarction in Otherwise Healthy Men

Arterial dissection is usually associated with pathological states such as malignant hypertension, severe atherosclerosis, severe trauma, Marfan syndrome, or Ehlers-Danlos syndrome. However, we report three cases in which renal artery dissection occurred in otherwise healthy, normotensive men. In two cases, the onset of symptoms of renal artery dissection was coincident with an unusual degree of physical activity. In the third case, the symptoms occurred while the patient was sitting but during a stressful business meeting. In each case, the patient experienced severe unilateral flank pain. Urolithiasis was suspected, but intravenous pyelography showed only ipsilateral impaired renal cortical perfusion, and the urinalyses showed no hematuria. The diagnosis of renal artery dissection was established by arteriography in two cases and by nephrectomy in one case. The latter case showed fibromuscular dysplasia by arteriography performed after the nephrectomy. The other two cases showed no evidence of fibromuscular dysplasia. We conclude that spontaneous renal artery dissection can occur in otherwise healthy individuals. Our experience and the reports of others indicate that this condition occurs mainly in men, conservative (nonsurgical) management is generally indicated, and the long-term prognosis is generally excellent. In some patients, an unusual degree of physical exertion might be the cause of renal artery dissection.
Optimization of detector pixel size for stent visualization in x-ray fluoroscopy.

Pixel size is of great interest in the flat-panel detector design because of its potential impact on image quality. In the particular case of angiographic x-ray fluoroscopy, small pixels are required in order to adequately visualize interventional devices such as guidewires and stents which have wire diameters as small as 200 and 50 {mu}m, respectively. We used quantitative experimental and modeling techniques to investigate the optimal pixel size for imaging stents. Image quality was evaluated by the ability of subjects to perform two tasks: detect the presence of a stent and discriminate a partially deployed stent from a fully deployed one in synthetic images. With measurements at 50, 100, 200, and 300 {mu}m, the 100 {mu}m pixel size gave the maximum contrast sensitivity for the detection experiment with the idealized direct detector. For an idealized indirect detector with a scintillating layer, an optimal pixel size was obtained at 200 {mu}m pixel size. A channelized human observer model predicted a peak at 150 and 170 {mu}m, for the idealized direct and indirect detectors, respectively. With regard to the stent deployment task for both detector types, smaller pixel sizes are favored and there is a steep drop in performance with larger pixels.more » In general, with the increasing exposures, the model and measurements give the enhanced contrast sensitivities and a smaller optimal pixel size. The effects of electronic noise and fill factor were investigated using the model. We believe that the experimental results and human observer model predications can help guide the flat-panel detector design. In addition, the human observer model should work on the similar images and be applicable to the future model and actual flat-panel implementations.« less