cssi/SciSciGPT-SciSciNet huggingface dataset:
Higher-Weight Heegner Points

In this paper we formulate a conjecture that partially generalizes the Gross–Kohnen–Zagier theorem to higher-weight modular forms. For ƒ ∊ S 2k (N) satisfying certain conditions, we construct a map from the Heegner points of level N to a complex torus /L ƒ defined by ƒ. We define higher-weight analogues of Heegner divisors on /L ƒ. We conjecture that they all lie on a line and that their positions are given by the coefficients of a certain Jacobi form corresponding to ƒ. In weight 2, our map is the modular parameterization map (restricted to Heegner points), and our conjectures are implied by Gross–Kohnen–Zagier. For any weight, we expect that our map is the Abel–Jacobi map on a certain modular variety, and so our conjectures are consistent with the conjectures of Beilinson–Bloch. We have verified that our map is the Abel–Jacobi map for weight 4. We provide numerical evidence to support our conjecture for a variety of examples.
Soft X-Ray Scattering and Halos from Dust

Small-angle scatterings of X-rays by interstellar dust particles create halos around X-ray sources. The halo intensity and its projected radial distribution around a source can provide important information on the spatial distribution of the dust along the line of sight to the source and on the physical properties of the scattering dust particles. Halos around X-ray point sources have been used by several authors to infer that the scattering dust particles are fluffy in nature, consisting of aggregates of smaller refractory particles with vacuum occupying a significant fraction of their volume. The nature and morphology of interstellar dust particles has recently gained new importance, since fluffy, composite dust particles have been suggested as a possible solution to the interstellar carbon "crisis." This crisis results from the discrepancy between the abundance of carbon in the interstellar medium available for creating dust and the significantly larger amount of carbon that must be in dust in order to account for the UV-optical interstellar extinction in the diffuse ISM. Previous studies of X-ray scattering have used the Rayleigh-Gans (RG) approximation to the differential scattering cross section to calculate halo properties. However, the validity of the RG approximation fails for energies below 1 keV. We use the exact Mie solution for the differential scattering cross section and find that, for these energies, the scattering becomes much less efficient than is predicted by the RG approximation. Furthermore, the effects of K and L shell absorption by atoms in the dust become important. The net effect is that the RG approximation systematically and substantially overestimates the intensity of the halo below 1 keV, relative to the Mie solution result. In particular, Mathis and coworkers used the weaker than expected halo intensity observed around Nova Cygni 1992 to conclude that interstellar dust must be fluffy. Using the Mie solution to the scattering intensity and including the effects of absorption, we find that, contrary to the conclusion of Mathis and coworkers, the halo around Nova Cygni 1992 does not require interstellar dust grains to be fluffy in nature and that the data are consistent with scattering from a mixture of bare refractory silicate and carbon grains as well.
Generation of esters from carboxylic acids using Appel's salt (4,5-dichloro-1,2,3-dithiazolium chloride)

Abstract Esters can be generated directly in good yields under mild conditions from the corresponding carboxylic acid and alcohol using Appel's salt (4,5-dichloro-1,2,3-dithiazolium chloride) and 2,6-lutidine.
Inequalities of correlation type for symmetric stable random vectors

Abstract We point out a certain class of functions f and g for which random variables f ( X 1 , …, X m ) and g ( X m + 1 , …, X k ) are non-negatively correlated for any symmetric jointly stable random variables X i . We also show another result that is related to the correlation problem for Gaussian measures of symmetric convex sets.
Markov chain approximations to singular stable-like processes

Abstract We consider the Markov chain approximations for a class of singular stable-like processes. First, we obtain properties of some Markov chains. Then we construct the approximating Markov chains and give a sufficient condition for the weak convergence of these chains to the singular stable-like processes.
Improved damage-tolerance analysis methodology

A computerized damage tolerance analysis methodology, which can be reliably used to predict the fatigue crack growth behavior and lives of various types of cracks contained in metallic structures, subjected to complex spectrum loadings, has been developed This analysis method was developed primarily for the performance of the damage-tolerance analysis in the detail design stage of any aircraft system A state of the art load interaction model, which accounts for both retardation and acceleration, as well as their coupling effect to crack growth behavior, has been incorporated in this analysis methodology in order to predict fatigue crack lives more ac curately A two dimensional growth option is provided to account for the shape change effect of part through cracks (PTC) such as surface flaws and corner cracks at holes. A linear approximation technique is used as the damage accumulation scheme for saving computation costs This methodology has been implemented into a new computer code, the CRKGRO program A series of crack growth data correlation studies has been conducted using CRKGRO Results demonstrated that this damage tolerance analysis methodology provides reliable predictions on fatigue crack growth lives for cracked specimens subjected to spectrum loadings of various classes of aircraft
Sodium methylthiolate as an efficient deprotecting agent for dicobalt hexacarbonyl complexes of acetylenes

Abstract Various dicobalt hexacarbonyl acetylene complexes were efficiently converted to the unprotected acetylene by the reaction of two molar equivalents of sodium methylthiolate. Yields and reaction times depend upon the choice of solvent. DMF proved to be the most efficient solvent, with the reaction proceeding at >80% conversion in 5 minutes at room temperature.
Hydrogen abstraction from trichlorosilane by the trichloromethyl and 1,1‐dichlorotrifluoroethyl radicals

The Arrhenius parameters for the reactions and have been measured. Reaction (2a) was generated and studied by the photolysis of tetrachloromethane in the presence of trichlorosilane and reaction(2b) by the photolysis of 1,1,1,-trichlorotrifluoroethane in the presence of trichlorosilane. The measured data are given by the expressions .
Feedback from galactic stellar bulges and hot gaseous haloes of galaxies

We demonstrate that the feedback from stellar bulges can, in principle, play an essential role in shaping the halo gas of galaxies with substantial bulge components by conducting 1D hydrodynamical simulations. The feedback model we consider consists of two distinct phases: (i) an early starburst during the bulge formation and (ii) a subsequent long-lasting mass and energy injection from stellar winds of low-mass stars and Type Ia supemovae. An energetic outward blastwave is initiated by the starburst and maintained and enhanced by the long-lasting stellar feedback. For a Milky Way like galactic bulge, this blastwave heats up the circum-galactic medium to a scale much beyond the virial radius, thus the gas accretion into the halo can be completely stopped. In addition to that, the long-lasting feedback in the later phase powers a galactic bulge wind that is reverse-shocked at a large radius in the presence of circum-galactic medium and hence maintains a hot gaseous halo. As the mass and energy injection decreases with time, the feedback evolves to a subsonic and quasi-stable outflow, which is enough to prevent halo gas from cooling. The two phases of the feedback thus re-enforce each other's impact on the gas dynamics. The simulation results demonstrate that the stellar bulge feedback may provide a plausible solution to the long-standing problems in understanding the Milky Way type galaxies, such as the 'missing stellar feedback' problem and the 'overcooling' problem. The central point of the present model is that the conspiracy of the two-phase feedback keeps a low density and a high temperature for the circum-galactic medium so that its X-ray emission is significantly lowered and the radiative cooling is largely suppressed. The simulations also show that the properties of the hot gas in the subsonic outflow state depend sensitively on the environment and the formation history of the bulge. This dependence and variance may explain the large dispersion in the X-ray to B-band luminosity ratio of the low L X /L B elliptical galaxies.
The acutely infected diabetic foot is not adequately evaluated in an inpatient setting

OBJECTIVE To evaluate the standard of evaluation and treatment of the infected diabetic foot ulceration at a 551-bed university teaching institution. DESIGN A retrospective review of a 4-year consecutive sample (1991-1994). POPULATION Two hundred fifty-five patients who were admitted to a hospital for care of an infected diabetic foot ulceration. Patients were subdivided into the following 4 dichotomous variables: (1) whether the patient underwent a lower-extremity amputation, (2) whether the patient was admitted once or multiple times, (3) whether the patient underwent intraoperative debridement, and (4) whether the patient was admitted to medical or surgical services. RESULTS All groups that were evaluated had undergone a less than adequate foot examination. Of the admitted patients, 31.4% did not have their pedal pulses documented; 59.7% of the admitted patients were not evaluated for the presence or absence of protective sensation. Nearly 90% of the wounds were not evaluated for involvement of underlying structures, and foot radiographs were not performed in 32.9% of the patients. There were more blood cultures ordered (62.0%) than wound cultures (51.4%). CONCLUSION The results of this study highlight the need for a systematic, detailed lower-extremity examination for every diabetic patient who is admitted to a hospital, particularly those who are admitted with a primary diagnosis that involves a foot complication.
Loose laplacian spectra of random hypergraphs

Let H = (V, E) be an r-uniform hypergraph with the vertex set V and the edge set E. For 1 ≤ s ≤ r/2, we define a weighted graph G(s) on the vertex set \documentclass{article}\usepackage{mathrsfs, amsmath, amssymb}\pagestyle{empty}\begin{document}${V\choose s}$\end{document}**image** as follows. Every pair of s-sets I and J is associated with a weight w(I, J), which is the number of edges in H containing I and J if I ∩ J = ∅, and 0 if I ∩ J ≠ ∅. The s-th Laplacian \documentclass{article}\usepackage{mathrsfs, amsmath, amssymb}\pagestyle{empty}\begin{document}$\mathcal L^{(s)}$\end{document} **image** of H is defined to be the normalized Laplacian of G(s). The eigenvalues of \documentclass{article}\usepackage{mathrsfs, amsmath, amssymb}\pagestyle{empty}\begin{document}$\mathcal L^{(s)}$\end{document} **image** are listed as \documentclass{article}\usepackage{mathrsfs, amsmath, amssymb}\pagestyle{empty}\begin{document}$\lambda^{(s)}_0, \lambda^{(s)}_1, \ldots, \lambda^{(s)}_{{n\choose s}-1}$\end{document} **image** in non-decreasing order. Let \documentclass{article}\usepackage{mathrsfs, amsmath, amssymb}\pagestyle{empty}\begin{document}$\bar\lambda^{(s)}(H)=\max_{i\neq 0}\{|1-\lambda^{(s)}_i|\}$\end{document} **image** . The parameters \documentclass{article}\usepackage{mathrsfs, amsmath, amssymb}\pagestyle{empty}\begin{document}$\bar\lambda^{(s)}(H)$\end{document} **image** and λ**math-image**(H), which were introduced in our previous paper, have a number of connections to the mixing rate of high-ordered random walks, the generalized distances/diameters, and the edge expansions. For 0 \documentclass{article}\usepackage{mathrsfs, amsmath, amssymb}\pagestyle{empty}\begin{document}$p(1-p)\gg \frac{\log^4 n}{n^{r-s}}$\end{document} **image** , and \documentclass{article}\usepackage{mathrsfs, amsmath, amssymb}\pagestyle{empty}\begin{document}$1-p\gg \frac{\log n}{n^2}$\end{document} **image** , we prove that almost surely \documentclass{article}\usepackage{mathrsfs, amsmath, amssymb}\pagestyle{empty}\begin{document}\begin{align*} \bar\lambda^{(s)}(H^r(n,p))\leq \frac{s}{n-s}+ (3+o(1))\sqrt{\frac{1-p}{{n-s\choose r-s}p}}.\end{align*}\end{document} We also prove that the empirical distribution of the eigenvalues of \documentclass{article}\usepackage{mathrsfs, amsmath, amssymb}\pagestyle{empty}\begin{document}$\mathcal L^{(s)}$\end{document} **image** for Hr(n, p) follows the Semicircle Law if \documentclass{article}\usepackage{mathrsfs, amsmath, amssymb}\pagestyle{empty}\begin{document}$p(1-p)\gg \frac{\log^{1/3} n}{n^{r-s}}$\end{document} **image** and \documentclass{article}\usepackage{mathrsfs, amsmath, amssymb}\pagestyle{empty}\begin{document}$1-p\gg \frac{\log n}{n^{2+2r-2s}}$\end{document} **image** . © 2012 Wiley Periodicals, Inc. Random Struct. Alg., 2012 © 2012 Wiley Periodicals, Inc.
ON PRODUCTS OF QUASICONVEX SUBGROUPS IN HYPERBOLIC GROUPS

An interesting question about quasiconvexity in a hyperbolic group concerns finding classes of quasiconvex subsets that are closed under finite intersections. A known example is the class of all quasiconvex subgroups [1]. However, not much is yet learned about the structure of arbitrary quasiconvex subsets. In this work we study the properties of products of quasiconvex subgroups; we show that such sets are quasiconvex and their finite intersections have a similar algebraic representation and, thus, are quasiconvex too.
The underdevelopment of health or the health of underdevelopment: an analysis of the distribution of human health resources in Latin America.

In this presentation it is postulated that the present maldistribution of human health resources in Latin America is brought about by the same determinants that cause the underdevelopment of most of that continent. It is indicated that contrary to the theories of development prevalent in the corridors of power and academic circles of developed countries (as well as in the leading circles of developing countries and in the international agencies) underdevelopment and the uneven distribution of resources both inside and outside the health sector is not due to the absence of cultural and technologic diffusion from developed to developing countries; or to the scarcity of capital in poor nations; or to the presence of dual economies in underdeveloped countries (the urban-entrepreneurial economy and the rural primitive economy). On the contrary underdevelopment and the concomitant maldistribution of resources is caused by the existence of the assumed "conditions" of development; i.e. the cultural technologic and the economic dependency of developing countries and economic and political control of resources by specific interests and social groups--the national lumpen-bourgeoisie and its foreign counterparts. Moreover these 2 factors bring about the so-called dual economies in those countries. The uneven distribution by type of health care region social class and by subsectors (private public social security) of human health resources described in this article is shown to be explained by the same determinants which cause underdevelopment in Latin America. (authors)
Synthesis, structure and properties of a new intermetallic compound, Ca7Ni4Sn13

Abstract Crystals of a new intermetallic compound, Ca7Ni4Sn13, have been prepared. The refined structure was solved in the P4/m space group, Z = 1 with lattice constants a = 11.200(1) A and c = 4.594(1) A , R = 2.8% and Rw = 2.4%. This new structure type consists of an Sn-Ni network forming channels parallel to the c axis which are filled with calcium atoms. Temperature-dependent magnetic and conductivity studies show Ca7Ni4Sn13 to be Pauli paramagnetic with simple metallic behavior.
Analysis of acoustic emission signals in machining

Acoustic emission (AE) signals are emerging as promising means for monitoring machining processes, but understanding their generation is presently a topic of active research; hence techniques to analyze them are not completely developed. In this paper, we present a novel methodology based on chaos theory, wavelets and neural networks, for analyzing AE signals. Our methodology involves a thorough signal characterization, followed by signal representation using wavelet packets, and state estimation using multilayer neural networks. Our methodology has yielded a compact signal representation, facilitating the extraction of tight set of features for flank wear estimation.
Hydrothermal crystal growth of the potassium niobate and potassium tantalate family of crystals

Single crystals of KNbO{sub 3} (KN), KTaO{sub 3} (KT), and KTa{sub 1-x}Nb{sub x}O{sub 3} (x=0.44, KTN) have been prepared by hydrothermal synthesis in highly concentrated KOH mineralizer solutions. The traditional problems of inhomogeneity, non-stoichiometry, crystal striations and crystal cracking resulting from phase transitions associated with this family compounds are minimized by the hydrothermal crystal growth technique. Crystals of good optical quality with only minor amounts of metal ion reduction can be grown this way. Reactions were also designed to provide homogeneous distribution of tantalum and niobium metal centers throughout the KTN crystal lattice to maximize its electro-optic properties. Synthesis was performed at relatively low (500-660 {sup o}C) temperatures in comparison to the flux and Czochralski techniques. This work represents the largest crystals of this family of compounds grown by hydrothermal methods to date. -- Graphical Abstract:
Discrete Dynamical Models Showing Pattern Formation in Subaqueous Bedforms

A new class of “toy models” for subaqueous bedform formation are proposed and examined. These models all show a similar mechanism of wavelength selection via bedform unification, and they may have applications to bedform stratigraphy. The models are also useful for exploring general issues of pattern formation and complexity in stochastically driven far-from-equilibrium systems.
Projective Modules Over Frobenius Algebras and Hopf Comodule Algebras

This note presents some results on projective modules and the Grothendieck groups K 0 and G 0 for Frobenius algebras and for certain Hopf Galois extensions. Our principal technical tools are the Higman trace for Frobenius algebras and a product formula for Hattori-Stallings ranks of projectives over Hopf Galois extensions.
Practical Field Alignment of Parabolic Trough Solar Concentrators

In this paper a new technique for parabolic trough mirror alignment based on the use of an innovative theoretical overlay photographic (TOP) approach is described. The technique is a variation on methods used to align mirrors on parabolic dish systems. It involves overlaying theoretical images of the heat collection element (HCE) in the mirrors onto carefully surveyed photographic images and adjustment of mirror alignment until they match. From basic geometric principles, for any given viewer location the theoretical shape and location of the reflected HCE image in the aligned mirrors can be predicted. The TOP approach promises to be practical and straightforward, and inherently aligns the mirrors to the HCE. Alignment of an LS-2 mirror module on the rotating platform at the National Solar Thermal Test Facility (NSTTF) with the TOP technique along with how it might be implemented in a large solar field is described. Comparison of the TOP alignment to the distant observer approach on the NSTTF LS-2 is presented and the governing equations used to draw the theoretical overlays are developed. Alignment uncertainty associated with this technique is predicted to be less than the mirror slope error.
Directional heterogeneity in distance profiles in hedonic property value models

Abstract In environmental economics, hedonic property value (HPV) models have often employed distance from a localized environmental disamenity as a proxy for perceived risk. The magnitude of a distance effect on housing prices, however, may depend upon the direction in which it is being measured. We generalize conventional distance models to allow for continuously varying directional effects by converting from Cartesian to polar coordinates. A simple empirical example (for housing prices around Woburn, Massachusetts, between 1988 and 1996) illustrates how failure to allow for directional heterogeneity can obscure otherwise statistically significant distance effects in HPV.
A 2- mu m BiCMOS process utilizing selective epitaxy

The authors describe a BiCMOS process that incorporates a high-performance n-p-n bipolar structure with a cutoff frequency (f/sub T/) of 5 GHz and an isolated nonoptimized vertical p-n-p bipolar structure to a 2- mu m twin-well CMOS process with poly-to-n/sup +/ capacitors. These high-performance structures are incorporated with only two additional masking steps without affecting the performance of the NMOS and PMOS transistors of the original CMOS process. The device characteristics for the NMOS and PMOS transistors are similar to those of the MOS transistors of the original CMOS process. The device characteristics of the vertical n-p-n and p-n-p transistors, as well as the NMOS and PMOS transistors, are described. >
Quantum chaos in open versus closed quantum dots: Signatures of interacting particles

Abstract This paper reviews recent studies of mesoscopic fluctuations in transport through ballistic quantum dots, emphasizing differences between conduction through open dots and tunneling through nearly isolated dots. Both the open dots and the tunnel-contacted dots show random, repeatable conductance fluctuations with universal statistical properties that are accurately characterized by a variety of theoretical models including random matrix theory, semiclassical methods and nonlinear sigma model calculations. We apply these results in open dots to extract the dephasing rate of electrons within the dot. In the tunneling regime, electron interaction dominates transport since the tunneling of a single electron onto a small dot may be sufficiently energetically costly (due to the small capacitance) that conduction is suppressed altogether. How interactions combine with quantum interference are best seen in this regime.
Some special aspects of the stereochemistry of coordination compounds

Presentation de differents types de coordination dans des complexes metalliques. Synthese bibliographique
Factor Endowments and the Returns to Skill: New Evidence from the American Past

Existing skill-biased technical change theory predicts that differences in factor endowments will affect technology adoption and the return to skill. We document regional variation in endowments in the American past. We then estimate the returns to education using a new data source: a report from the Commissioner of Education in 1909. We find significant variation in the returns to schooling aligned with differences in resource endowments, with large (within-occupation) returns in the Midwest and Southwest but much lower returns in the South and West. Our results appear generalizable to broader returns to education in the United States.
Anesthetic implications for the management of patients with acute myocardial infarction: a matched cohort study of patients undergoing emergency myocardial revascularization.

Emergency coronary artery bypass grafting (CABG) is advocated as a treatment of acute myocardial infarction (AMI). To attempt to define anesthetic management problems in this patient group, a retrospective study was conducted comparing the perioperative courses of 23 patients undergoing emergency CABG during AMI with 23 elective patients, individually matched for gender, operating surgeon, ejection fraction, and aortic crossclamp time. The 23 AMI patients were anesthetized 5.98 +/- 3.0 (range 1.5 to 11.0) hours after the onset of chest pain. Anesthetic agents were similar for both groups. Induction of anesthesia was well tolerated by AMI patients. Tolerance of cardioplegic arrest was impaired in the AMI group as evidenced by the sharp increase in frequency of inotropic support required to discontinue bypass in the AMI group compared to elective patients (12/23 v 3/23; P less than .005). Fifteen AMI patients who received preoperative streptokinase had greater postoperative bleeding. Three AMI patients died postoperatively. The number of patients requiring prolonged postoperative ventilation and extended ICU care was higher in the AMI group. It is concluded that patients undergoing emergency CABG during AMI represent a greater risk than elective patients. They have a higher incidence of myocardial dysfunction following cardioplegic arrest during bypass. Those who receive preoperative thrombolytic therapy exhibit greater bleeding tendencies.
Tandem reduction–reductive alkylation of azido sugars

Abstract Catalytic hydrogenation of azido sugars has been conducted in the presence of different aldehydes to bring about a tandem reduction–reductive alkylation sequence. The reaction sequence proceeds in generally high yields, and tolerates some benzyl and benzylidene protecting groups that are sensitive to hydrogenolysis.
Type inference for record concatenation and multiple inheritance

Abstract We show that the type inference problem for a lambda calculus with records, including a record concatenation operator, is decidable. We show that this calculus does not have principal types, but does have finite complete sets of types: that is, for any term M in the calculus, there exists an effectively generable finite set of type schemes such that every typing for M is an instance of one of the schemes in the set. We show how a simple model of object-oriented programming, including hidden instance variables and multiple inheritance, may be coded in this calculus. We conclude that type inference is decidable for object-oriented programs, even with multiple inheritance and classes as first-class values.
Observational Constraints on the Ages of Molecular Clouds and the Star Formation Timescale: Ambipolar-Diffusion-controlled or Turbulence-induced Star Formation?

We revisit the problem of the star formation timescale and the ages of molecular clouds. The apparent overabundance of star-forming molecular clouds over clouds without active star formation has been thought to indicate that molecular clouds are "short-lived" and that star formation is "rapid." We show that this statistical argument lacks self-consistency and, even within the rapid star formation scenario, implies cloud lifetimes ≈10 Myr. We discuss additional observational evidence from external galaxies that indicate lifetimes of molecular clouds and a timescale of star formation of ≈107. These long cloud lifetimes, in conjunction with the rapid (≈1 Myr) decay of supersonic turbulence, present severe difficulties for the scenario of turbulence-controlled star formation. By contrast, we show that all 31 existing observations of objects for which the line width, the size, and the magnetic field strength have been reliably measured are in excellent quantitative agreement with the predictions of the ambipolar-diffusion theory. Within the ambipolar-diffusion-controlled star formation theory, the line widths may be attributed to large-scale nonradial cloud oscillations (essentially standing large-amplitude, long-wavelength Alfven waves), and the predicted relation between the line width, the size, and the magnetic field is a natural consequence of magnetic support of self-gravitating clouds.
Reynolds-Averaged Navier-Stokes Simulations of Airfoils and Wings with Ice Shapes

Numerical simulations using the Reynolds-averaged Navier‐Stokes equations were conducted to investigate the effect of simulated ridge and leading-edge ice shapes on the aerodynamic performance of airfoils and wings. A range of Reynolds numbers and Mach numbers, as well as ice-shape sizes and ice-shape locations, were examined for the NACA 23012, the NLF 0414, and the NACA 3415 airfoils. The results were compared to experiments completed recently at NASA Langley and University of Illinois. Additional two thinner airfoil models and a tapered NACA 23012 wing were also studied to investigate ice-shape location effect for various geometries. Comparisons between simulation results and experimental force data showed favorable comparison up to the stall conditions, with improved fidelity for forward and smaller ice shapes. At and past stall condition strong separation occurs, and the aerodynamic forces were typically not predicted accurately for large upper-surface ice shapes. To alleviate this problem, a lift-break (pseudostall) condition was defined based on the lift-curve slope change. The lift break compared reasonably well with experimental stall conditions and indicated that the upper-surface critical ice-shape location tended to be near (and often in between) the location of minimum pressure and the location of the most adverse pressure gradient.
Fluctuations of Matrix Entries of Regular Functions of Wigner Matrices

We study the fluctuations of the matrix entries of regular functions of Wigner random matrices in the limit when the matrix size goes to infinity. In the case of the Gaussian ensembles (GOE and GUE) this problem was considered by A. Lytova and L. Pastur (J. Stat. Phys. 134:147–159, 2009). Our results are valid provided the off-diagonal matrix entries have finite fourth moment, the diagonal matrix entries have finite second moment, and the test functions have four continuous derivatives in a neighborhood of the support of the Wigner semicircle law. Moreover, if the marginal distributions satisfy the Poincare inequality our results are valid for Lipschitz continuous test functions.
Official Exchange Rate Arrangements and Real Exchange Rate Behavior

We study the behavior of real exchange rates under various official designations of exchange rate arrangements. Examining many currencies, we find important differences across the designations. Most notably, real exchange rate mean reversion is fastest when nominal exchange rates are officially pegged. We also find a large nonlinear effect: adjustment is fastest when the real exchange rate deviates greatly from its mean. This nonlinear effect is also most striking among officially pegged currencies. Finally, we find that nominal exchange rates, rather than prices, do most of the adjusting.
The Many Streams of the Magellanic Stream

We present results from neutral hydrogen (H I) observations of the tip of the Magellanic Stream (MS), obtained with the Arecibo telescope as a part of the ongoing survey by the consortium for Galactic studies with the Arecibo L-band Feed Array. We find four large-scale, coherent H I streams, extending continuously over a length of 20°, each stream possessing different morphology and velocity gradients. The newly discovered streams provide strong support for the tidal model of the MS formation by Connors et al. (2006), who suggested a spatial and kinematic bifurcation of the MS. The observed morphology and kinematics suggest that three of these streams could be interpreted as a three-way splitting of the main MS filament, while the fourth stream appears much younger and may have originated from the Magellanic Bridge. We find an extensive population of H I clouds at the tip of the MS. Two-thirds of clouds have an angular size in the range 3.5'-10'. We interpret this as being due to thermal instability, which would affect a warm tail of gas trailing through the Galactic halo over a characteristic timescale of a few Myr to a few hundred Myr. We show that thermal fragments can survive in the hot halo for a long time, especially if surrounded by a <106 K halo gas. If the observed clumpy structure is mainly due to thermal instability, then the tip of the MS is at a distance of ~70 kpc. A significant fraction of H I clouds at the tip of the MS show multiphase velocity profiles, indicating the coexistence of cooler and warmer gas.
Localization Lengths and Boltzmann Limit for the Anderson Model at Small Disorders in Dimension 3

We prove lower bounds on the localization length of eigenfunctions in the three-dimensional Anderson model at weak disorders. Our results are similar to those obtained by Schlag, Shubin and Wolff, [J. Anal. Math. 88 (2002)], for dimensions one and two. We prove that with probability one, most eigenfunctions have localization lengths bounded from below by \(O \left({\lambda^{-2} \over \log {1 \over \lambda}}\right)\), where λ is the disorder strength. This is achieved by time-dependent methods which generalize those developed by Erdos and Yau [Commun. Pure Appl. Math. LIII: 667–753 (2003)] to the lattice and non-Gaussian case. In addition, we show that the macroscopic limit of the corresponding lattice random Schrodinger dynamics is governed by a linear Boltzmann equation.
Selective laser ionization for mass-spectral isotopic analysis

Resonant enhancement of the ionization process can provide a high degree of elemental selectivity, thus eliminating or drastically reducing the interference problem. In addition, extension of this method to isotopically selective ionization has the potential for greatly increasing the range of isotope ratios that can be determined experimentally. This gain can be realized by reducing or eliminating the tailing of the signal from the high-abundance isotope into that of the low-abundance isotope, augmenting the dispersion of the mass spectrometer. We briefly discuss the hardware and techniques used in both our pulsed and cw RIMS experiments. Results are presented for both cw ionization experiments on Lu/Yb mixtures, and spectroscopic studies of multicolor RIMS of Tc. Lastly, we discuss practical limits of cw RIMS analysis in terms of detection limits and measurable isotope ratios.
Database querying under changing preferences

We present here a formal foundation for an iterative and incremental approach to constructing and evaluating preference queries. Our main focus is query modification: a query transformation approach which works by revising the preference relation in the query. We provide a detailed analysis of the cases where the order-theoretic properties of the preference relation are preserved in the revision. We consider a number of different revision operators: union, prioritized and Pareto composition. We also formulate algebraic laws that enable incremental evaluation of preference queries. Finally, we consider two variations of the basic framework: finite restrictions of preference relations and weak-order extensions of strict partial order preference relations.
Solid-State Structural Characterization of a Rigid Framework of Lacunary Heteropolyniobates

In our ongoing investigations of heteropolyniobate chemistry, a phase featuring decorated, A-type trivacant alpha-Keggin ions linked by their charge-balancing sodium cations has been isolated and structurally characterized. This is the first heteropolyniobate reported that has a true lacunary structure type. Na15[(PO2)3PNb9O34] x 22 H2O (1) [triclinic space group P1 (No. 2); a = 12.242 (2) A, b = 12.291 (3) A, c = 22.056 (4) A; alpha = 93.12 (3) degrees, beta = 99.78 (3) degrees, gamma = 119.84 (3) degrees; Z = 4, V = 2799.2 (10) A3] is composed of bilayers of the heteropolyanions alternating with layers of hydrated Na+ cations. Sodium cations also bridge the clusters within their layers through Na-O(t)-Nb, Na-O(b)-Nb2, and Na-O(t)-P bonds (t = terminal and b = bridging). This phase is poorly soluble in water, suggesting that it is more characteristic of a framework of linked heteropolyanions rather than a water-soluble heteropolyanion salt. Two-dimensional solid-state 23Na multiple-quantum magic angle spinning (MAS) NMR of 1 reveals five distinctive chemical and structural environments for sodium, which agrees with the crystallographic data. The 23Na and 1H MAS NMR studies further illustrate the rigid and immobile nature of this framework of cations and anions.
A high-performance cathode for the next generation of solid-oxide fuel cells

Fuel cells directly and efficiently convert chemical energy to electrical energy. Of the various fuel cell types, solid-oxide fuel cells (SOFCs) combine the benefits of environmentally benign power generation with fuel flexibility. However, the necessity for high operating temperatures (800–1,000 °C) has resulted in high costs and materials compatibility challenges. As a consequence, significant effort has been devoted to the development of intermediate-temperature (500–700 °C) SOFCs. A key obstacle to reduced-temperature operation of SOFCs is the poor activity of traditional cathode materials for electrochemical reduction of oxygen in this temperature regime2. Here we present Ba_(0.5_Sr_(0.5)Co_(0.8)Fe_(0.2)O_(3-delta) (BSCF) as a new cathode material for reduced-temperature SOFC operation. BSCF, incorporated into a thin-film doped ceria fuel cell, exhibits high power densities (1,010 mW cm^(-2) and 402 mW cm^(-2) at 600 °C and 500 °C, respectively) when operated with humidified hydrogen as the fuel and air as the cathode gas. We further demonstrate that BSCF is ideally suited to 'single-chamber' fuel-cell operation, where anode and cathode reactions take place within the same physical chamber. The high power output of BSCF cathodes results from the high rate of oxygen diffusion through the material. By enabling operation at reduced temperatures, BSCF cathodes may result in widespread practical implementation of SOFCs.
Natural convection-radiation interaction in boundary-layer flow over horizontal surfaces

Analyse mathematique de l'interaction entre la convection naturelle et le rayonnement thermique dans un ecoulement de couche limite laminaire sur une plaque horizontale isotherme. Presentation de resultats numeriques pour des gaz avec une valeur du nombre de Prandtl de 0,7
Supine Empty Stress Test as a Predictor of Low Valsalva Leak Point Pressure

Our objective was to determine whether a positive supine empty stress test is predictive of a low Valsalva leak point pressure (< or =60 cm of water). Evaluation was carried out on 179 patients with a history of genuine stress incontinence confirmed with urodynamic testing. All patients had a supine stress test performed after voiding. Residual urine determinations were all <100 cc. A vesical Valsalva leak point pressure determination (cough and strain) was performed during multichannel urodynamics with 150 cc in the bladder. Urethral profilometry was performed at maximum capacity. There was a statistically significant relationship between a low leak point pressure and a positive supine empty stress test (P < 0.000). The supine empty stress test had a sensitivity of 79% and a specificity of 62.5% for the detection of a low leak point pressure. The negative predictive value was high at 90%. For the age group 50 years and younger the negative predictive value was 95%. However, there was no significant relationship between a positive supine empty stress test and a low maximal urethral closure pressure. We conclude that the supine empty stress test is a useful screening test for a low leak point pressure but not a low urethral closure pressure. Its high negative predictive value is useful in excluding the presence of a low leak point pressure and may help the clinician to determine which patients with genuine stress incontinence need further assessment of the dynamic function of the urethral sphincter.
EXTREME PARTICLE ACCELERATION IN MAGNETIC RECONNECTION LAYERS: APPLICATION TO THE GAMMA-RAY FLARES IN THE CRAB NEBULA

The gamma-ray space telescopes AGILE and Fermi detected short and bright synchrotron gamma-ray flares at photon energies above 100 MeV in the Crab Nebula. This discovery suggests that electron-positron pairs in the nebula are accelerated to PeV energies in a milligauss magnetic field, which is difficult to explain with classical models of particle acceleration and pulsar wind nebulae. We investigate whether particle acceleration in a magnetic reconnection layer can account for the puzzling properties of the flares. We numerically integrate relativistic test-particle orbits in the vicinity of the layer, including the radiation reaction force, and using analytical expressions for the large-scale electromagnetic fields. As they get accelerated by the reconnection electric field, the particles are focused deep inside the current layer where the magnetic field is small. The electrons suffer less from synchrotron losses and are accelerated to extremely high energies. Population studies show that, at the end of the layer, the particle distribution piles up at the maximum energy given by the electric potential drop and is focused into a thin fan beam. Applying this model to the Crab Nebula, we find that the emerging synchrotron emission spectrum peaks above 100 MeV and is close to the spectral shapemore » of a single electron. The flare inverse Compton emission is negligible and no detectable emission is expected at other wavelengths. This mechanism provides a plausible explanation for the gamma-ray flares in the Crab Nebula and could be at work in other astrophysical objects such as relativistic jets in active galactic nuclei.« less
Characterization of neodymium trichloride hydrates and neodymium hydroxychloride

Abstract Neodymium trichloride hexahydrate (NdCl3 · 6H2O) was dehydrated by heating it in either air, argon, HCl or argon-HCl mixtures to germinate the intermediate species. The hexahydrate (NdCl3 · 6H2O) was found to decompose to pentahydrate (NdCl3 · 5H2O) which in turn decomposed to tetrahydrate (NdCl3 · 4H2O). The latter decomposed to monohydrate (NdCl3 · H2O) as the dehydration proceeded towards anhydrous NdCl3. Simultaneously to dehydration, formation of neodymium oxychloride (NdOCl) and neodymium hydroxychloride (Nd(OH)2Cl) took place. Nd(OH)2Cl was isolated and characterized by X-ray diffraction. Its decomposition temperature was determined to be 376°C by differential thermal analysis. Its heat of decomposition to NdOCl and H2O was determined by differential scanning calorimetry to be 23479 cal mol−1 (98283 J mol−1). Its density was found to be 4.596 g cm−3 at 25 °C.
Regular expression constrained sequence alignment

We introduce regular expression constrained sequence alignment as the problem of finding the maximum alignment score between given strings S"1 and S"2 over all alignments such that in these alignments there exists a segment where some substring s"1 of S"1 is aligned to some substring s"2 of S"2, and both s"1 and s"2 match a given regular expression R, i.e. s"1,s"[email protected]?L(R) where L(R) is the regular language described by R. For complexity results we assume, without loss of generality, that n=|S"1|>=|m|=|S"2|. A motivation for the problem is that protein sequences can be aligned in a way that known motifs guide the alignments. We present an O(nmr) time algorithm for the regular expression constrained sequence alignment problem where r=O(t^4), and t is the number of states of a nondeterministic finite automaton N that accepts L(R). We use in our algorithm a nondeterministic weighted finite automaton M that we construct from N. M has O(t^2) states where the transition-weights are obtained from the given costs of edit operations, and state-weights correspond to optimum alignment scores we compute using the underlying dynamic programming solution for sequence alignment. If we are given a deterministic finite automaton D accepting L(R) with t"d states then our construction creates a deterministic finite automaton M"d with t"d^2 states. In this case, our algorithm takes O(t"d^2nm) time. Using M"d results in faster computation than using M when t"d
Automatic data processing in larger manufacturing plants

If you have ever tried to drag a small child through a toy department, while trying to catch a train, you will have some feeling for the troubles of the Production Control Manager. He is faced with a never ending stream of unexpected troubles, all of which tend to keep him from making good his schedule. Development of ingenious methods to solve this problem has helped some, but in many cases, both the problem and ulcers remain.
Global solutions to special Lagrangian equations

We show that any global solution to the special Lagrangian equations with the phase larger than a critical value must be quadratic.
Is the Path to Higher Exports in India Paved with Export Zones

Enclave based policies to promote exports, and consequently economic growth, are not new to India. India’s first export zone started in 1964 and six more central government zones were operational by the mid 1990s. However, these zones explain only a fraction of export growth rates in India. Statistics show that during the pre-reform years, these zones contributed to less than five per cent of total exports and even now contribute to less than fifteen per cent of total exports from India. There seems to be no obvious correlation between export growth and export zones that warrants the spate of new zones in the country. Partial trade liberalisation since the mid 1980s and general reforms since 1991 seems to better explain export growth.
Probing lepton gluonic couplings at the LHC

Abstract In an effective Lagrangian description of physics beyond the standard model, gluonic couplings of leptons that respect the symmetries of the standard model occur in operators of dimension eight. Normally the effect of such operators is much suppressed in processes that occur at energies below the scale of new physics. For this reason usual studies of the effective Lagrangian are limited to the lowest dimension operators which is typically six. We point out that the large parton luminosity for gluon–gluon interactions at the LHC places these gluonic couplings to leptons within observable reach for a new physics scale near one TeV.
Computers in architectural education

It is perhaps difficult to understand that even today the design of the built environment is best described as an "art" rather than a "science." The designer or architect is an artist who relies heavily on creativity and intuition to solve technological problems.
Impact of the 87Rb singlet scattering length on suppressing inelastic collisions

A computation of $^{87}\mathrm{\ensuremath{-}}^{87}$Rb spin-exchange rate constants as functions of the two-body singlet scattering length ${\mathrm{a}}_{\mathrm{s}}$ demonstrates that the inelastic collision rate is suppressed over a small range of the possible values for ${\mathrm{a}}_{\mathrm{s}}$. A two-channel model relates this inelastic suppression to an interference phenomenon, manifested in the near coincidence of the singlet and triplet scattering lengths. This mechanism explains the diminished rates measured in recent ``double-trap'' experiments. Combining information extracted from these rates and from previous scattering length measurements allows us to place bounds on the $^{87}\mathrm{Rb}$ singlet scattering length (74--102 a.u.).
Phosphinate-containing heterocycles: A mini-review

This review provides an overview of recent efforts towards the synthesis of phosphinate heterocycles R1R2P(O)(OR). Our laboratory and others’ have been involved in this field and as a result new P–C, P–N, and P–O containing heterocyclic motifs are now available through a variety of methods. While developing rapidly, this area is still in its infancy so that biological testing of the compounds has not yet been conducted and applications are rare. The growing availability of synthetic methods will undoubtedly change this situation in the near future.