cssi/SciSciGPT-SciSciNet huggingface dataset:
Characterization of Swirl-Venturi Lean Direct Injection Designs for Aviation Gas Turbine Combustion

Injector geometry, physical mixing, chemical processes, and engine cycle conditions together govern performance, operability, and emission characteristics of aviation gas turbine combustion systems. The present investigation explores swirl-venturi lean direct injection combustor fundamentals, characterizing the influence of key geometric injector parameters on reacting flow physics and emission production trends. In this computational study, a design space exploration was performed using a parameterized swirl-venturi lean direct injector model. From the parametric geometry, 20 three-element lean direct injection combustor sectors were produced and simulated using steady-state Reynolds-averaged Navier–Stokes reacting computations. Species concentrations were solved directly using a reduced 18-step reaction mechanism for Jet A. Turbulence closure was obtained using a nonlinear κ-e model. Results demonstrate sensitivities of the geometric perturbations on axially averaged flowfield responses. Output variable...
Hidden Symmetries of Large N QCD

there is no einbein-gravitino on this theory, which makes it a 1D topological supergravity, or locally SUSY quantum mechanics. Using this symmetry, we derive the large Nc loop equation in momentum superloop space. Introducing as before the position operator XI' we argue that the superloop equation is equivalent to invariance of correlation functions of products of these operators with respect to certain quadrilinear transformation. As a consequence of this nonlinear symmetry, the coefficients of the Voiculesku expansion of the position operator satisfy recurrent equations. The generators of this symmetry are involved in the glueball spectrum, as it follows from the loop-loop correlation function equation. The correlation functions of external flavor currents in the background of constant flavor gauge field with finite density of topological charge in the chiral limit are also considered. We represent them as certain finite dimensional integrals in superspace, involving the Green's function, which is expressed in terms of XI'. The expansion in powers of external momenta k1, · · · , kn is calculable in terms of the above universal numbers in the Voiculesku expansion.
Foreign direct investment: The factors affecting the location of foreign branch plants in the United States

Broad trends in the regional dispersion, industrial composition, and source country of foreign investment in manufacturing branch plants over the 1977-1986 period are described. Regression analysis, with states as the unit of observation, is used to investigate the factors important to the location decision of foreign firms. The regression model is desegregated to look at high-tech and non-high-tech manufacturing plants, and by source country of the investment (Japan, Europe and all other countries). The results indicate that nearness to markets is the dominant factor influencing the location of foreign manufacturing branch plants in the United States. Other factors analyzed include labor market conditions, access to transportation facilities, state effort in attracting foreign industry, corporate tax rates, availability of skilled labor, and construction costs
Distributing Pollution Rights in Cap-and-Trade Programs: Are Outcomes Independent of Allocation?

Standard economic theory predicts that if property rights to pollute are clearly established, equilibrium outcomes in an efficient emissions permit market will be independent of how the emissions permits are initially distributed. This so-called independence property has important implications for policy design and implementation. Past studies document a strong positive correlation between the initial permit allocation and firm-level emissions, raising concerns that the independence property is failing to hold in real-world settings. We exploit the random assignment of firms to different permit allocation cycles in Southern California's RECLAIM program in order to test the independence of permit allocation and emissions. Our results lend empirical support to the independence hypothesis.
Vibrational spectra, methyl torsional potential functions, internal rotational potential functions, and conformational properties of ethyl vinyl ether

The vibrational spectra of ethyl vinyl ether in both the fluid and solid states have been recorded from 20 to 3500 cm−1. The 33 fundamental modes of vibration have been assigned. Three rotational isomers have been observed and their structures have been determined. The most stable conformer, s-cis/s-trans, is planar and of Cs symmetry. The two less stable rotamers, skew/s-trans and skew/gauche, are non-planar and of Ci molecular symmetry. The barrier to internal rotation of the methyl rotor has been determined for each conformation; these barriers are 3.43 kcal mol−1 (s-cis/s-trans), 3.35 kcal mol−1 (skew/s-trans) and 3.19 kcal mol−1 (skew/gauche). A potential function for each of the two asymmetric internal rotations has been calculated and barriers to conformer interconversion have been determined. From the asymmetric potential function calculations, ΔH, the enthalpy difference between the conformers, has been determined. The s-cis/s-trans conformer is 1.87 kcal mol−1 more stable than the skew/s-trans conformer; the skew/s-trans conformer is more stable than the skew/gauche conformer by 1.10 kcal mol−1. The energetics of conformer interconversion and methyl internal rotation have been described in terms of molecular geometry and non-bonded interactions. These results are compared to those found in other alkyl vinyl and dialkyl ethers.
Wnt5b–Ryk pathway provides directional signals to regulate gastrulation movement

Noncanonical Wnts are largely believed to act as permissive cues for vertebrate cell movement via Frizzled (Fz). In addition to Fz, Wnt ligands are known to regulate neurite outgrowth through an alternative receptor related to tyrosine kinase (Ryk). However, Wnt–Ryk signaling during embryogenesis is less well characterized. In this study, we report a role for Wnt5b as an instructive cue to regulate gastrulation movements through Ryk. In zebrafish, Ryk deficiency impairs Wnt5b-induced Ca2+ activity and directional cell movement. Wnt5b–Ryk signaling promotes polarized cell protrusions. Upon Wnt5b stimulation, Fz2 but not Ryk recruits Dishevelled to the cell membrane, suggesting that Fz2 and Ryk mediate separate pathways. Using co-culture assays to generate directional Wnt5b cues, we demonstrate that Ryk-expressing cells migrate away from the Wnt5b source. We conclude that full-length Ryk conveys Wnt5b signals in a directional manner during gastrulation.
Wavelength and temperature performance of polarization-transforming fiber

We have theoretically and experimentally investigated an optical fiber with circular polarization modes on one end and linear polarization modes on the other end. We call this fiber a polarization-transforming fiber because the local modes, or polarization states they represent, are converted from linear to circular, and visa versa, in the fiber. We have developed and implemented a postdraw process for making polarization-transforming fiber samples 30 mm long with losses less than 1 dB and a polarization-mode conversion from circular to linear greater than 20 dB. Also, we have modeled and measured the dependence on wavelength and temperature of polarization-transforming fiber samples. The measured normalized wavelength dependence of a sample fiber 30 mm long was approximately 1.4 x 10(-4) nm(-1), and the measured normalized temperature dependence was approximately 6 x 10(-4) degrees C(-1). These values are better in some cases than values for conventional high-birefringent fiber quarter-wave plates.
Computerized measurement of mammographic display image quality

Since the video monitor is widely believed to be the weak link in the imaging chain, it is critical, to include it in the total image quality evaluation. Yet, most physical measurements of mammographic image quality are presently limited to making measurements on the digital matrix, not the displayed image. A method is described to quantitatively measure image quality of mammographic monitors using ACR phantom-based test patterns. The image of the test pattern is digitized using a charge coupled device (CCD) camera, and the resulting image file is analyzed by an existing phantom analysis method (Computer Analysis of Mammography Phantom Images, CAMPI). The new method is called CCD-CAMPI and it yields the Signal-to-Noise-Ratio (SNR) for an arbitrary target shape (e.g., speck, mass or fiber). In this work we show the feasibility of this idea for speck targets. Also performed were physical image quality characterization of the monitor (so-called Fourier measures) and analysis by another template matching method due to Tapiovaara and Wagner (TW) which is closely related to CAMPI. The methods were applied to a MegaScan monitor. Test patterns containing a complete speck group superposed on a noiseless background were displayed on the monitor and a series of CCD images were acquired. These images were subjected to CCD-CAMPI and TW analyses. It was found that the SNR values for the CCD-CAMPI method tracked those of the TW method, although the latter measurements were considerably less precise. The TW SNR measure was also about 25% larger than the CCD-CAMPI determination. These differences could be understood from the manner in which the two methods evaluate the noise. Overall accuracy of the CAMPI SNR determination was 4.1% for single images when expressed as a coefficient of variance. While the SNR measures are predictable from the Fourier measures the number of images and effort required is prohibitive and it is not suited to Quality Control (QC). Unlike the Fourier measures and the TW method, CCD-CAMPI is capable of yielding speck SNR on a single image. This is based on preliminary work and more complete testing is underway. Based on the early promising results, we expect that the CCD-CAMI method can be adapted to routine image QC of monitors using inexpensive equipment.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
In vivo and in vitro structure-dosimetry-activity relationships of substituted phenols in developmental toxicity assays.

Abstract Structure-dosimetry-activity relationships (SDARs) of a series of substituted phenols were evaluated following exposure of gestation day 11 rats in vivo and in comparable stage embryos in vitro. In the in vivo study, 27 congeners were assayed and log P (a term used synomously with lipophilicity in this paper) and Hammett sigma values (a measure of the electronic withdrawing ability of the substituent) were shown to correlate with maternal toxicity; however, no relationships between these parameters and developmental effects were observed. In the in vitro system, 13 congeners were evaluated and molar refractivity and/or lipophilicity were shown to correlate with the ability of the phenols to induce embryonic growth retardation and structural defects in the absence of the hepatocytes. In contrast, when a metabolic activating system (primary hepatocytes) was present in the in vitro system, the potential to induce growth retardation was inversely related to lipophilicity, although the relationships were weaker than the positive relationship seen without the hepatocytes. The binding of the phenols to macromolecules in the culture medium was highly correlated with log P. Correcting the in vitro potency data for the variable amount of binding improved the predictiveness of the quantitative structure-activity relationships (QSARs). The potential to induce embryotoxicity in vitro was not well correlated with the potential to induce developmental toxicity in vivo: whereas the in vitro data demonstrates that the phenols are intrinsically embryotoxic, few of them actually produced significant developmental toxicity in the in vivo system, and there were few positive correlations between effects observed in the two systems. Embryonic dosimetry obtained for the in vitro assay system indicated that the principal determining factor in producing embryotoxicity of a phenol in vitro is the ability to gain access into the embryo, but that once in the embryo, the lipophilic phenols are more toxic on a per molecule basis. Furthermore, embryonic dosimetry data for two phenols indicated that for a given exposure, in vitro embryos will accumulate more of a phenol than will the in vivo embryos. In summary, we have undertaken a systematic study of the response of in vivo and in vitro embryos to a series of structural analogues, and attempted to relate the potency of the congeners to specific physicochemical properties. While different conclusions were reached about the potency of the phenols in the two systems, the assessment of pharmacokinetic parameters provided insight into the deposition and activity of these congeners in the embryo and have pointed us in the direction of determining the reason(s) for the differences that we observed.
A probabilistic representation of solutions of the incompressible Navier-Stokes equations in R3

A new probabilistic representation is presented for solutions of the incompressible Navier-Stokes equations in R3 with given forcing and initial velocity. This representation expresses solutions as scaled conditional expectations of functionals of a Markov process indexed by the nodes of a binary tree. It gives existence and uniqueness of weak solutions for all time under relatively simple conditions on the forcing and initial data. These conditions involve comparison of the forcing and initial data with majorizing kernels.
Information technology and privacy: conceptual muddles or privacy vacuums?

Within a given conversation or information exchange, do privacy expectations change based on the technology used? Firms regularly require users, customers, and employees to shift existing relationships onto new information technology, yet little is known as about how technology impacts established privacy expectations and norms. Coworkers are asked to use new information technology, users of gmail are asked to use GoogleBuzz, patients and doctors are asked to record health records online, etc. Understanding how privacy expectations change, if at all, and the mechanisms by which such a variance is produced will help organizations make such transitions. This paper examines whether and how privacy expectations change based on the technological platform of an information exchange. The results suggest that privacy expectations are significantly distinct when the information exchange is located on a novel technology as compared to a more established technology. Furthermore, this difference is best explained when modeled by a shift in privacy expectations rather than fully technology-specific privacy norms. These results suggest that privacy expectations online are connected to privacy offline with a different base privacy expectation. Surprisingly, out of the five locations tested, respondents consistently assign information on email the greatest privacy protection. In addition, while undergraduate students differ from non-undergraduates when assessing a social networking site, no difference is found when judging an exchange on email. In sum, the findings suggest that novel technology may introduce temporary conceptual muddles rather than permanent privacy vacuums. The results reported here challenge conventional views about how privacy expectations differ online versus offline. Traditionally, management scholarship examines privacy online or with a specific new technology platform in isolation and without reference to the same information exchange offline. However, in the present study, individuals appear to have a shift in their privacy expectations but retain similar factors and their relative importance--the privacy equation by which they form judgments--across technologies. These findings suggest that privacy scholarship should make use of existing privacy norms within contexts when analyzing and studying privacy in a new technological platform.
Gauge symmetries and amplitudes in N=2 strings

Abstract Picture-changed operators are discussed in N = 2 strings with space-time signature (2, 2). A gauge symmetry algebra is derived in a background of torus space-time T 2,2 and its simple representation on the picture-changed operators is given. Simple Ward identities associated with the gauge algebra and their consequence for three- and four-point amplitudes of arbitrary loops are also discussed.
Universal commutative operator algebras and transfer function realizations of polynomials

To each finite-dimensional operator space E is associated a commutative operator algebra UC(E), so that E embeds completely isometrically in UC(E) and any completely contractive map from E to bounded operators on Hilbert space extends uniquely to a completely contractive homomorphism out of UC(E). The unit ball of UC(E) is characterized by a Nevanlinna factorization and transfer function realization. Examples related to multivariable von Neumann inequalities are discussed.
Melting processes under microgravity conditions

Abstract The kinetics of melting pivalic acid (PVA) dendrites was observed under convection-free conditions on STS-87 as part of the United States Microgravity Payload Mission (USMP-4) flown on Columbia in 1997. Analysis of video data show that PVA dendrites melt without relative motion with respect to the quiescent melt phase. Dendritic fragments display shrinking to extinction, with fragmentation occurring at higher initial supercoblings. Individual fragments follow a characteristic time-dependence derived elsewhere. The microgravity melting kinetics against which the experimental observations are compared is based on conduction-limited quasi-static melting under shape-preserving conditions. Agreement between analytic theory and our experiments is found when the melting process occurs under shape-preserving conditions as measured using the C A ratio of individual needle-like crystal fragments.
Proteolysis, fibrinolysis, and coagulation. Significance in thrombolytic therapy.

The fibrinolytic mechanism, one of the blood protease systems, constitutes a fourth phase of clotting, which contributes to maintenance of coagulation in delicate balance. "Shwartzman"-induced in vivo coagulation, combined with fibrinolysin, produces profound clotting defects with severe hemostatic failure, in contrast to the relative innocuousness of either alone. The same defects are obtainable in vitro. The thrombin-fibrinogen interaction is blocked, simulating the in vivo "afiibrinogenemia." These observations are pertinent to thrombolytic therapy invoked for conditions where intravascular clotting may be occurring. Fibrinogen clottability is also blocked by trypsin. Apparently, fibrinolysin, thrombin, and trypsin are competitive for fibrinogen. Trypsin, as, well as other proteases, markedly activates factors II, VII, and X, resembling the action of thromboplastin. In contrast, fibrinolysin and thrombin are inert on these clotting factors, whereas on factor V they first activate and then destroy it. This explains why factor V depression is observed in thrombolytic therapy. The activating effect of trypsin on factors II, VII, and X precludes its use in thrombolytic therapy, and also draws attention to the tryptase-antitryptase equilibrium in normal and certain thrombotic states. The experimental observations help elucidate some clinical and clinicolaboratory findings in acquired "afibrinogenemia" and therapeutically induced "fibrinolytic" states. The retarded thrombin clotting time of the plasma, and reduction in prothrombic activity attributable to fibrinolytic depression of factor V, may be valuable guides to thrombolytic therapy.
Space-based hyperspectral technologies for the thermal infrared

Various approaches now exist for obtaining spectral imagery over a broad range of infrared wavelengths. One approach involves the use of a single grating element in two grating orders with dualband focal plane array (FPA) technology. This approach offers greater efficiency over the mid-wave infrared and long-wave infrared and eliminates the need for separate FPAs, dispersing elements, and optical beamsplitters. Another approach achieves similar results by exploiting an FPA which has a broad wavelength response with an innovative grating which has useable efficiency that extends beyond the single octave limits of traditional gratings. Significant advantages result, in either case, for space-based hyperspectral imagers, for which a reduction in cryo-cooled mass translates into prodigious savings in overall payload mass, cryo-cooling requirements, and waste heat removal. By contrast, longer term approaches might realize infrared “hyperspectral pixels” in two-dimensional imaging FPAs. In this case, each pixel would detect different wavelengths of radiation, at different depths, and the resulting “spectral photocurrents” would be transported to read-out circuitry through a vertical grid of electrical contacts. Although not yet realized in practice, the conceptual basis for accomplishing this, with the widely available HgCdTe detector material, has been described. With regard to employment, space-based thermal hyperspectral imaging is characterized by coarser ground resolution as a result of aperture diameter limitations and diffraction considerations at the longer infrared wavelengths. The resulting subpixel detections, based on spectral signature, are often complementary with higher resolution, shorter wavelength, panchromatic imagery.
High harmonic generation in relativistic laser-plasma interaction

High harmonics generated due to the scattering of relativistic electrons from high intensity laser light is studied. The experiments are carried out with an Nd:Glass laser system with a peak intensity of 2×1018 W cm−2 in underdense plasma. It is shown that, at high intensities, when the normalized electric field approaches unity, in addition to the conventional atomic harmonics from bound electrons there is significant contribution to the harmonic spectrum from free electrons. The characteristic signatures of this are found to be the emission of even order harmonics, linear dependence on the electron density, significant amount of harmonics even with circular polarization and a much smaller spatial region over which these harmonics are produced as compared to the atomic case. Imaging of the harmonic beam shows that it is emitted in a narrow cone with a divergence of 2 to 3 degrees.
Time-resolved microscope system to image material response following localized laser energy deposition: exit surface damage in fused silica as a case example

The dynamics of material response following initial localized energy deposition by the laser pulse on the material's surface is still largely unknown. We describe a time-resolved microscope system that enables the study of the sequence of events and the individual processes involved during the entire timeline from the initial energy deposition to the final state of the material, typically associated with the formation of a crater on the surface. To best capture individual aspects of the damage timeline, this system can be configured to multiple imaging arrangements, such as multiview image acquisition at a single time point, multi-image acquisition at different time points of the same event, and tailored sensitivity to various aspects of the process. As a case example, we present results obtained with this system during laser-induced damage on the exit surface of fused silica.
Communications options for computerized traffic control systems

This paper describes the current state of the art in communications technologies, as it applies to computerized traffic control systems. It analyzes the problems and tradeoffs required to achieve an optimal communications system linking the central processor to individual intersections of a CBD grid system as well as distributed stations along a freeway system. This report is based on a combination of analytical and practical experience gained in designing, developing, and implementing traffic control communications systems in both North America and Europe during the past 3 years.
Dupin hypersurfaces with four principal Curvatures, II

If M is an isoparametric hypersurface in a sphere S n with four distinct principal curvatures, then the principal curvatures κ1, . . . , κ4 can be ordered so that their multiplicities satisfy m 1 = m 2 and m 3 = m 4, and the cross-ratio r of the principal curvatures (the Lie curvature) equals −1. In this paper, we prove that if M is an irreducible connected proper Dupin hypersurface in R n (or S n ) with four distinct principal curvatures with multiplicities m 1 = m 2 ≥ 1 and m 3 = m 4 = 1, and constant Lie curvature r = −1, then M is equivalent by Lie sphere transformation to an isoparametric hypersurface in a sphere. This result remains true if the assumption of irreducibility is replaced by compactness and r is merely assumed to be constant.
Regioselective Intramolecular Dipolar Cycloaddition of Azides and Unsymmetrical Alkynes

Enantioenriched allenylsilanes are used in three-component propargylation reactions with aldehydes and silyl ethers to form syn-homopropargylic ethers that contain an imbedded azide. These materials then undergo thermally induced intramolecular 1,3-dipolar cycloaddition reactions, resulting in unique fused ring systems containing 1,2,3-triazoles. The ability to modify all three components of the reaction allows for expedient access to compounds containing significant structural and stereochemical variation.
Simulations of X-ray emission from Omega fill tube experiments

Abstract The capsules used in ignition experiments on the National Ignition Facility (NIF) laser will have a layer of frozen DT inside a low-Z shell. Liquid DT will be injected through a narrow fill tube that penetrates the shell and is frozen in place. The fill tube is a perturbation on the surface of the capsule and hydrodynamic instabilities will cause this perturbation to grow during an implosion. Experiments to investigate the growth of perturbations due to fill tubes have been carried out on the Omega laser. The goal of these experiments was to validate simulations at Omega energy scales and thus increase confidence in the use of simulations in planning for NIF experiments. Simulations show that the fill tube leads to a jet of shell material that penetrates into the DT fuel. Simulations will be used to pick experimental conditions in which the jet is small enough that it does not significantly reduce the yield of a NIF implosion. This paper compares experiments in which bumps and stalks were used as fill tube surrogates to 2D simulations of X-ray emission from Omega capsule implosions. Experiments and simulations are in reasonable agreement on the size of a bump or stalk required to produce a jet that is visible above the emission from a (nominally) smooth capsule.
Infinitesimal Perturbation Analysis for Quasi-Dynamic Traffic Light Controllers

Abstract We consider the traffic light control problem for a single intersection modeled as a stochastic hybrid system. We study a quasi-dynamic policy based on partial state information defined by detecting whether vehicle backlogs are above or below certain controllable thresholds. Using Infinitesimal Perturbation Analysis (IPA), we derive online gradient estimators of a cost metric with respect to these threshold parameters and use these estimators to iteratively adjust the threshold values through a standard gradient-based algorithm so as to improve overall system performance under various traffic conditions. Results obtained by applying this methodology to a simulated urban setting are also included.
"A place like that": advance directives and nursing home admissions.

Decisions about admitting a mentally incapacitated person to a nursing home raise a variety of difficult legal, ethical, and public policy issues. A strategy for anticipating and addressing this contingency prospectively, by encouraging execution of formal advance planning directives while the individual is still capable, may mitigate some of the dilemmas associated with these issues. The author discusses the contours and feasibility of such a strategy, analyzing nursing home admission on one's behalf and for refusing such admission, or placing explicit conditions on such admission, in advance of the time that the actual decision must be made.
Geometric aspects of quantum spin states

A number of interesting features of the ground states of quantum spin chains are analyzed with the help of a functional integral representation of the system's equilibrium states. Methods of general applicability are introduced in the context of the SU(2S+1)-invariant quantum spin-S chains with the interaction −P(o), whereP(o) is the projection onto the singlet state of a pair of nearest neighbor spins. The phenomena discussed here include: the absence of Neel order, the possibility of dimerization, conditions for the existence of a spectral gap, and a dichotomy analogous to one found by Affleck and Lieb, stating that the systems exhibit either slow decay of correlations or translation symmetry breaking. Our representation elucidates the relation, evidence for which was found earlier, of the −P(o) spin-S systems with the Potts and the Fortuin-Kasteleyn random-cluster models in one more dimension. The method reveals the geometric aspects of the listed phenomena, and gives a precise sense to a picture of the ground state in which the spins are grouped into random clusters of zero total spin. E.g., within such structure the dichotomy is implied by a topological argument, and the alternatives correspond to whether, or not, the clusters are of finite mean length.
Feasible optimality of vegetation patterns in river basins

[1] We examine mechanisms leading to organization of vegetation patterns within the channel network structure of a semi-arid New Mexico river basin under the controlling influence of water stress. We compare the actual pattern of water stress within the basin to patterns resulting from two algorithms of local stress optimization which proceed from an initial fully random vegetation distribution. Here we show that the distribution of vegetation and basin water stress derived from an algorithm that maintains local optimization within the network flow path exhibits considerably better agreement with the actual distribution than one that ignores the network structure of the basin. These results suggest the pattern of actual vegetation observed within the basin corresponds to a condition of feasible optimality in which organization is constrained by the stochastic nature of local interactions mediated by the network configuration. The principles of such organization have important consequences regarding the interaction between land cover change and hydrological dynamics in river basins, as well as the biogeographical evolution of landscapes.
Compensatory education and social justice

In past generations, as today, it is true that "the world is in chaos. Our own country faces the most menacing social and economic problems it has ever known. Where can it look for salvation?... Certainly we can hope to do nothing to stave off the collapse of Western civilization if we remain absorbed in the frivolous and irrelevant occupations that consume the attention of many scholars and many faculties."1
Evaluation of Performance of Bridge Deck Expansion Joints

The bridge deck expansion joint is an important element in the functioning of bridge structures. When joints fail to function properly, they can create problems out of proportion to their size. Selection of a good joint for use can create fewer bridge maintenance problems. The purpose of the study was to evaluate the performance of several types of joints currently in use on Indiana highway bridges. The types of joints investigated are compression seal, strip seal, integral abutment, poured silicone, and polymer modified asphalt. The research was accomplished through questionnaire surveys, analysis of Indiana Department of Transportation roadway management data, and expert interviews. The questionnaire survey identified the problems and their causes and the merits and potential improvements of each type of joint. The analysis of Indiana roadway management data ranked the performance of different types of joints based on the deterioration rates estimated by the regression coefficients. The expert interviews investigated the practices of Indiana and its surrounding states regarding the selection and maintenance of joints. Based on the research results, several suggestions were proposed to ensure the longer service life of expansion joints.
Windscreen Dirt and Surface Damage Effects

It is reasonable to assume that the condition of the windscreen has something to do with the ability of a driver to see through it. One study implies that seeing ability is impaired by scratched windscreens, a second evaluates cleaning methods for improving the wettabllity of the glass surface to improve the ability to see through ft, a third evaluates water repellent materials for use on aircraft windscreens and a fourth concludes from three windscreens that surface damage reduces the perceptibility of objects on the roadway. (See text.) This study was designed: (a) to obtain a population sample of automobile windscreen surface damage and dirt accumulation, (b) to evaluate the ability to see through the dirt and surface damage in a static and dynamic driving situation, and (c) to evaluate the practicability of resurfacing automobile windscreens. Language: en
Identifying Supply and Demand Elasticities of Agricultural Commodities: Implications for the US Ethanol Mandate

We present a new framework to identify supply elasticities of storable commodities where past shocks are used as exogenous price shifters. In the agricultural context, past yield shocks change inventory levels and futures prices of agricultural commodities. We use our estimated elasticities to evaluate the impact of the 2009 Renewable Fuel Standard on commodity prices, quantities, and food consumers’ surplus for the four basic staples: corn, rice, soybeans, and wheat. Prices increase 20 per cent if one-third of commodities used to produce ethanol are recycled as feedstock, with a positively skewed 95 percent confidence interval that ranges from 14 to 35 per cent. (JEL Q11, Q16, Q42, Q48)
Research Note: Athletic Graduation Rates and Simpson's Paradox.

Abstract Graduation rates for male athletes overall as well as men's football and basketball players lag behind those of male non-athletes at Division I colleges and universities. Scholarship athletes, however, are much more likely to be drawn from racial and ethnic groups with lower average graduation rates. After accounting for differences in racial composition, graduation rates for male athletes overall as well football players match or exceed those of their peers, and racial differences account for over one-quarter of the shortfall in men's basketball graduation rates. This is a classic example of Simpson's Paradox.
Endothelial actin depolymerization mediates NADPH oxidase-superoxide production during flow reversal

Slow moving blood flow and changes in flow direction, e.g., negative wall shear stress, can cause increased superoxide (O2·−) production in vascular endothelial cells. The mechanism by which shear ...
Seongomycin: A new sulfur-containing benzo[b]fluorene derived from genes clustered with those for kinamycin biosynthesis

Abstract Streptomyces lividans ZX7 transformed with a ∼40 KB fragment of S. murayamaensis DNA produces the kinamycin biosynthetic intermediates kinobscurinone (1) and stealthin C (2a), as well as seongomycin (3), which had been previously observed in S. murayamaensis UV mutant MCl.
A molecular dynamics study of grain boundary behavior at elevated temperatures using an embedded atom potential

Analyse theorique de la stabilite des joints de grains pres du point de fusion dans du cuivre
Symbolic Mobilization? The Impact of Candidate Sex in American Elections

The increase in the number of women candidates in American politics has raised questions about whether the presence of these women has an impact on the public by mobilizing attitudes and behaviors....
Seller strategies on eBay: Does size matter?

We examine seller tactics in 1177 eBay auctions. The largest volume sellers make rather homogeneous choices; smaller sellers are more heterogeneous. Some tactics, such as starting the auction with a 'Buy it Now' offer, appear to increase revenue. Perhaps due to intense competition, however, the overall impact of most tactics appears to be quite small. The main exception is the use of a secret reserve price, which raises the winning bid conditional on a sale, but reduces the probability of a sale. This can be advantageous, depending on the seller's risk aversion and impatience.
Investigation of porphyrin-forming reactions. Part 1. Pyrrole + aldehyde oligomerization in two-step, one-flask syntheses of meso-substituted porphyrins

A deep understanding of the two-step, one-flask synthesis of meso-substituted porphyrins requires characterization of the acyclic oligomers, which typically constitute ≥50% of the products. We have employed laser desorption mass spectrometry (LD-MS) to obtain a qualitative yet high resolution view of the oligomer content of crude oxidized reaction mixtures. This methodology complements other analytical methods which provide information regarding yields of porphyrin, other macrocyclic products, and unreacted aldehyde. Our findings include the following. (1) Crude oxidized porphyrin reaction mixtures provided peaks in the LD-MS spectrum which were readily assigned to oligomers (m/z 100–2000) derived from pyrrole–aldehyde condensation. The oligomers comprised one of four series depending on the ratio of pyrrole and aldehyde units. (2) Quite disparate reaction conditions that gave good yields of porphyrin also afforded a similar oligomer composition. (3) The change in the nature of the oligomers over time was readily monitored. (4) The maximum yield of porphyrin and the maximum diversity of the oligomer composition were attained at similar times. (5) The decline in yield of porphyrin at long reaction time was accompanied by truncation, not elongation, of oligomers. (6) The onset of the truncation of oligomers and the decline in yield of porphyrin were accompanied by a decrease of the aldehyde to low levels. (7) Pyrrole was incorporated into the growing oligomers more rapidly than aldehyde. Taken together, these studies show how various conditions alter the course of the pyrrole–aldehyde condensation.
Relaxin: a disulfide homolog of insulin

Relaxin, a peptide hormone responsible for the widening of the birth canal in mammals, has been purified from the ovaries of pregnant hogs. The amino acid sequences of its constituent A and B chains were determined, and the positions of the disulfide cross-links were established. Relaxin was shown to be identical to insulin with respect to its disulfide bond distribution, but significant homology was lacking in other positions. These findings suggest that relaxin and insulin were derived from a common ancestral gene. Since the intrauterine mode of propagation is synonymous with the development of mammals, the genetic distance between insulin and relaxin should therefore permit an estimate of the earliest possible time of commitment of one evolutionary branch to the development of mammals. This event was estimated to have occurred about 5 X 10(8) years ago.
The primary visual cortex fills in color

One of the most important goals of visual processing is to reconstruct adequate representations of surfaces in a scene. It is thought that surface representation is produced mainly in the midlevel vision and that area V1 (the primary visual cortex) activity is solely due to feedback from the midlevel stage. Here, we measured functional MRI signals corresponding to “neon color spreading”: an illusory transparent surface with long-range color filling-in, one of the important mediums in reconstructing a surface. The experiment was conducted with careful controls of attention, which can send feedback signals from higher visual areas. Activity for filling-in was observed only in V1, whereas activity for illusory contours was observed in multiple visual areas. These results indicate that surface representation is produced by multiple rather than single processing.
Synthesis and biological activity of folic acid and methotrexate analogues containing L-threo-(2S,4S)-4-fluoroglutamic acid and DL-3,3-difluoroglutamic acid

The stereospecific syntheses of L-threo-gamma-fluoromethotrexate (1t) and L-threo-gamma-fluorofolic acid (3t) are reported. Compounds 1t and 3t have no substrate activity with folylpoly-gamma-glutamate synthetase isolated from CCRF-CEM human leukemia cells, and compound 1t inhibits human dihydrofolate reductase at similar levels as methotrexate. The synthesis of DL-3,3-difluoroglutamic acid (6) and its incorporation into DL-beta,beta-difluorofolic acid (4) are also reported. Compound 4 acts as a better substrate for human CCRF-CEM folylpoly-gamma-glutamate synthetase than folic acid (V/K = ca. 7-fold greater). Thus, replacement of the glutamate moiety of methotrexate and folic acid with 4-fluoroglutamic acid and 3,3-difluoroglutamic acid results in folates and antifolates with altered polyglutamylation activity.
The orbifold-string theories of permutation-type: I. One twisted BRST per cycle per sector

We resume our discussion of the new orbifold-string theories of permutation-type, focusing in the present series on the algebraic formulation of the general bosonic prototype and especially the target space-times of the theories. In this first paper of the series, we construct one twisted BRST system for each cycle j in each twisted sector σ of the general case, verifying in particular the previously-conjectured algebra $ {\left[ {{{\hat{Q}}_i}\left( \sigma \right),{{\hat{Q}}_j}\left( \sigma \right)} \right]_{+} } = 0 $ of the BRST charges. The BRST systems then imply a set of extended physical-state conditions for the matter of each cycle at cycle central charge ĉ j (σ) = 26f j (σ), where f j (σ) is the length of cycle j.
Stereothresholds with simulated vergence variability and constant error

Abstract Stereothresholds are elevated by vergence constant error (fixation disparity), vergence noise, or both. This study investigated the separate and combined effects of simulated vergence constant error and variability on stereothresholds in four normal observers. Targets were 30 arc min bright vertical lines presented separately to the two eyes for 150 ms in darkness. Vergence constant error, simulated as a pedestal disparity, was induced by altering the screen positions of the stereo half-images relative to a previously visible binocular fixation point. Vergence variability was simulated simultaneously by disconjugate motion (amplitude=0–0.5 deg per eye; frequency=2 or 4 Hz) of a pair of scanning mirrors in a Wheatstone stereoscope that was used to present the images to each eye. Various combinations of pedestal disparity and simulated vergence variability produce equivalent stereothresholds whenever the calculated mean deviation ( ∑| instantaneous vergence errors |/N ) of the stimulus from the fixation plane is the same. In particular, stereothresholds are optimal for mean deviations up to approximately 1.4 arc min and then increase according to a power function with an exponent of 0.61. The results imply that vergence constant errors and vergence variability impair stereothresholds because of the resulting mean deviation from the horopter.
Acute heart failure guidelines: moving in the right direction?

In the June issue of the Journal of Cardiac Failure, the Heart Failure Society of America (HFSA) published its 2010 Comprehensive Heart Failure Practice Guideline designed to update and expand the 2006 Guideline.[1] Section 12 of the guideline, Evaluation and Management of the Patient with Acute Decompensated Heart Failure, is specifically directed at the practitioner evaluating patients with acute symptoms, including emergency physicians. This section provides guidance and recommendations for diagnosis, treatment and disposition of the patient being evaluated and treated for acute heart failure (AHF). However, a closer look at this guideline brings up several important points and suggestions about the development of subsequent guidelines for the treatment of AHF. While the Guideline offers useful recommendations for the care of the patient with AHF, it is largely based on expert consensus, retrospective in-hospital data, or observational levels of evidence, thus pointing out the evidence-base for AHF needs to be improved dramatically. For emergency physicians, this is particularly important as it relates to the early management of AHF, where there is a significant shortfall of evidence to offer guidance with Level A recommendations. This suggests the a priori collaboration by the major stakeholders, such as cardiology, EM, and internal medicine, is likely to facilitate research which will significantly improve the evidence base for bother the early and late management of the AHF patient.
Did globular clusters reionize the Universe

A problem still unsolved in cosmology is the identification of the sources of radiation able to reionize H I in the intergalactic medium (IGM) by z∼6. Theoretical work and observations seem to indicate that the fraction,(f e s c ), of HI ionizing radiation emitted from galaxies that escapes into the IGM is small in the local Universe ((f e s c )? 10 per cent). At high redshift, galaxies are more compact and probably gas-rich, implying smaller values of (f e s c ) from their discs or spheroids. However, if the sites of star formation are displaced from the disc or spheroid and the star formation efficiency of the proto-clusters is high, then (f e s c ) should be about 1. This star formation scenario is consistent with several models for globular cluster formation. Using simple arguments based on the observed number of globular cluster systems in the local Universe, and assuming that the oldest globular clusters formed before reionization and had (f e s c ) ∼1, I show that they produced enough ionizing photons to reionize the IGM at z 6.
The Role of Domestic Debt Markets in Economic Growth: An Empirical Investigation for Low-Income Countries and Emerging Markets

This paper develops a new public domestic debt database covering 93 low-income countries and emerging markets over 1975–2004 to estimate the growth impact of domestic debt. Moderate levels of noninflationary domestic debt, as a share of GDP and bank deposits, are found to exert a positive overall impact on economic growth. Granger-causality regressions suggest support for a variety of channels: improved monetary policy; broader financial market development; strengthened domestic institutions/accountability; and enhanced private savings and financial intermediation. There is some evidence that, above a ratio of 35 percent of bank deposits, domestic debt begins to undermine growth, lending credence to traditional crowding out and bank efficiency concerns. Importantly, the growth contribution of domestic debt is higher if it is marketable, bears positive real interest rates, and is held outside the banking system.
Cyclodidemnamide: A new cyclic heptapeptide from the marine ascidian Didemnum Molle

Summary Cyclodidemnamide ( 1 ), a new cyclic heptapeptide, has been isolated from the marine ascidian Didemnum molle collected in the Philippine Islands. The structure of the new, weakly cytotoxic, heptapeptide was unambiguously assigned using comprehensive NMR analysis in combination with hydrolysis and chiral GC-MS analysis of its component amino acids. Computer analysis of 1 led to assignment of a solution conformation that fully rationalized the nOe correlations and shielding effects observed by 1 H NMR.