cssi/SciSciGPT-SciSciNet huggingface dataset:
Syntheses, structure, magnetism, and optical properties of the interlanthanide sulfides δ-Ln2−xLuxS3 (Ln=Ce, Pr, Nd)

Abstract δ-Ln2−xLuxS3 (Ln=Ce, Pr, Nd; x=0.67–0.71) compounds have been synthesized through the reaction of elemental rare-earth metals and S using a Sb2S3 flux at 1000 °C. These compounds are isotypic with CeTmS3, which has a complex three-dimensional structure. It includes four larger Ln3+ sites in eight- and nine-coordinate environments, two disordered seven-coordinate Ln3+/Lu3+ positions, and two six-coordinate Lu3+ ions. The structure is constructed from one-dimensional chains of LnSn (n=6–9) polyhedra that extend along the b-axis. These polyhedra share faces or edges with two neighbors within the chains, while in the [ac] plane they share edges and corners with other chains. Least square refinements gave rise to the formulas of δ-Ce1.30Lu0.70S3, δ-Pr1.29Lu0.71S3 and δ-Nd1.33Lu0.67S3, which are consistent with the EDX analysis and magnetic susceptibility data. δ-Ln2−xLuxS3 (Ln=Ce, Pr, Nd; x=0.67–0.71) show no evidence of magnetic ordering down to 5 K. Optical properties measurements show that the band gaps for δ-Ce1.30Lu0.70S3, δ-Pr1.29Lu0.71S3, and δ-Nd1.33Lu0.67S3 are 1.25, 1.38, and 1.50 eV, respectively. Crystallographic data: δ-Ce1.30Lu0.70S3, monoclinic, space group P21/m, a=11.0186(7), b=3.9796(3), c=21.6562(15) A, β=101.6860(10), V=929.93(11), Z=8; δ-Pr1.29Lu0.71S3, monoclinic, space group P21/m, a=10.9623(10), b=3.9497(4), c=21.5165(19) A, β=101.579(2), V=912.66(15), Z=8; δ-Nd1.33Lu0.67S3, monoclinic, space group P21/m, a=10.9553(7), b=3.9419(3), c=21.4920(15) A, β=101.5080(10), V=909.47(11), Z=8.
Effect of anisotropy on morphological instability in the freezing of a hypercooled melt

Abstract Considered is the morphological instability of a rapid-solidification front propagating in a hypercooled melt when the solidification process is controlled by kinetics and there are cubic anisotropies of surface tension and attachment kinetics. It is shown that, due to anisotropy, the threshold of morphological instability depends on the direction of the crystal growth and generates, in the general case, traveling cells (waves) propagating on the solidification front in a preferred direction determined by the anisotropy coefficients. Weakly nonlinear analysis of the waves is carried out in the vicinity of the instability threshold and it is shown that the evolution of the waves is usually governed by an anisotropic dissipation-modified Korteweg-de Vries equation. In special cases it is governed by an anisotropic Kuramoto-Sivashinsky equation that describes stationary cells. Regions in the parameter space are found where the stationary and traveling cells are stable and could be observed in experiment. The characteristics of the cells are studied as functions of the direction of the crystal growth.
Magnetic field effects on multiple scattering lifetimes

Abstract We have calculated the splitting of the multiple scattering longitudinal and transverse lifetimes of the excited states of a gas due to impressed magnetic fields.
Higher order mode acoustic transmission through the walls of rectangular ducts

Abstract As an extension of previous work on low frequency fundamental mode acoustic transmission through the walls of rectangular ducts, results are presented here on the transmission of internally propagated higher order acoustic modes through the duct walls. Subject to various assumptions, it is possible to obtain a closed form solution to the structural wave equation governing the motion of the duct's walls, and this is used to predict the response of the walls to the internal pressure field. The resultant acoustic radiation is estimated here by assuming that the duct radiates like a circular cylinder with the same surface velocity distribution. Both experimental and theoretical results are given and agreement between the two is tolerably good.
Modeling the appearance of special effect pigment coatings

Metallic and pearlescent coatings are becoming increasingly important in automotive, currency, and cosmetic applications. These coatings consist of metallic or dielectric platelets suspended in a binder, and are often applied between a pigmented basecoat, and a transparent topcoat. The scattering properties of these composite coatings vary depending upon the incident and viewing directions, as well as the wavelength. The complex nature of the scattering arises from the competition between multiple scattering sources: front surface reflection from the topcoat, reflection from the platelets, diffuse scattering from the pigmented undercoat, and scattering between platelets. The complex interplay between multiple scattering sources affects the ability to achieve quality control during the preparation of these coatings. In addition, the topcoat surface morphology, the properties of the pigmented basecoat, and the intrinsic properties, concentration, and angular distribution of the platelets influence the final appearance of the coating. In this paper, we will present models for light scattering from front surface facet reflection, subsurface flake reflection, and diffuse subsurface scattering. Experimental scattering measurements on pearlescent coatings show that the polarization can be well described in different geometry regimes by these different scattering sources. The models can be used to extract the slope distribution function of the flakes from the intensity data, but some aspects of the results behave inconsistently. Comparison is also made between experimental and calculated diffuse reflectance spectra. These results are intended to enable improved characterization of special effect coatings necessary for quality control and appearance modeling applications.
Beam induced RF cavity transient voltage

Abstract We calculate the transient voltage induced in a radio frequency (RF) cavity by the injection of a relativistic bunched beam into a circular accelerator. A simplified model of the beam induced voltage, using a single tone current signal, is generated and compared with the voltage induced by a more realistic model of a point-like bunched beam. The high Q limit of the bunched beam model is shown to be related simply to the simplified model. Both models are shown to induce voltages at the resonant frequency ωr of the cavity and at an integer multiple of the bunch revolution frequency (i.e. the accelerating frequency for powered cavity operation) hω0. The presence of two nearby frequencies in the cavity leads to a modulation of the carrier wave exp(jhω0t). A special emphasis is placed in this paper on studying the modulation function. These models prove useful for computing the transient voltage induced in superconducting RF cavities, which was the motivation behind this research. The modulation of the transient cavity voltage discussed in this paper is the physical basis of the recently observed and explained new kind of longitudinal rigid dipole mode which differs from the conventional Robinson mode.
Capitalists of All Russia, Unite! Business Mobilization Under Debilitated Dirigisme

Political mobilization of business forces in the post-communist world has crucial implications for economic development and civil society. The emergence of strong cross-sectoral business associations during Putin's presidency challenges the prevailing view of Russia's political economy as an informal, particularistic state–business exchange. At the theoretical level, collective action by socio-economic groups is linked to severe principal-agent dilemmas common to many ex-socialist bureaucracies. Given institutionally incoherent state structures, the state as principal facilitates collective action by business actors to create a parallel, non-state platform for policy formation and implementation. Such a dynamic of “debilitated dirigisme” should be understood in the comparative contexts of business mobilization in Latin America, Asia, and the advanced industrialized world. The argument developed here stands in contrast to two conventional approaches to business mobilization, “threat theory,” in which firms organize to resist various anti-capitalist forces, and “political entrepreneurship theory,” which holds that business is the passive object of mobilization by the state.
Digital Processing Of Synthetic Aperture Optical Imagery

A synthetic-aperture approach offers one method for obtaining high resolution optical imagery with low-mass, satellite-based optical telescopes. Images recorded sequentially with different aperture configurations are sampled and digitized, and appropriate spatial-frequency-domain processing is performed on a computer to obtain the desired high-resolution imagery. Special steps can be introduced in these post-detection processing operations that allow a substantial reduction in the optical tolerances that must be maintained by the aperture elements in the imaging process.
THE PROGENITOR OF THE TYPE Ia SUPERNOVA THAT CREATED SNR 0519-69.0 IN THE LARGE MAGELLANIC CLOUD

Models for the progenitor systems of Type Ia supernovae can be divided into double-degenerate systems, which contain two white dwarfs, and single-degenerate systems, which contain one white dwarf plus one companion star (either a red giant, a subgiant, or a >1.16 M ☉ main-sequence star). The white dwarf is destroyed in the supernova explosion, but any non-degenerate companion remains intact. We present the results of a search for an ex-companion star in SNR 0519-69.0, located in the Large Magellanic Cloud, based on images taken with the Hubble Space Telescope with a limiting magnitude of V = 26.05. SNR 0519-69.0 is confidently known to be from a Type Ia supernova based on its light echoes and X-ray spectra. The geometric center of the remnant (based on the Hα and X-ray shell) is at 05:19:34.83, –69:02:06.92 (J2000). Accounting for the measurement uncertainties, the orbital velocity, and the kick velocity, any ex-companion star must be within 47 of this position at the 99.73% confidence level. This circle contains 27 main-sequence stars brighter than V = 22.7, any one of which could be the ex-companion star left over from a supersoft source progenitor system. The circle contains no post-main-sequence stars, and this rules out the possibility of all other published single-degenerate progenitor classes (including symbiotic stars, recurrent novae, helium donors, and the spin-up/spin-down models) for this particular supernova. The only remaining possibility is that SNR 0519-69.0 was formed from either a supersoft source or a double-degenerate progenitor system.
Fatigue failure analysis of a leg press exercise machine

Abstract The following paper is an engineering failure analysis of an adjustment pin used in a leg press exercise machine. The pin is used to allow adjustment of the machine for people of different heights. It was modeled as a cantilever beam subjected to varying forces depending on the weight stack setting. The fracture occurred at a point of localized stress concentration. The analysis shows an elastic stress concentration of 1.67 which would cause plastic deformation and a fatigue stress concentration of 1.38 that led to the eventual fatigue failure. Based on actual user data, a block loading analysis was used to calculate a pin lifetime of approximately one year. The pin actually failed after 1 years of use. Design changes are recommended to reduce the size of the stress concentration and subsequently increase the life of the adjustment pin.
Evolving sets, mixing and heat kernel bounds

We show that a new probabilistic technique, recently introduced by the first author, yields the sharpest bounds obtained to date on mixing times of Markov chains in terms of isoperimetric properties of the state space (also known as conductance bounds or Cheeger inequalities). We prove that the bounds for mixing time in total variation obtained by Lovasz and Kannan, can be refined to apply to the maximum relative deviation |p n (x,y)/π(y)−1| of the distribution at time n from the stationary distribution π. We then extend our results to Markov chains on infinite state spaces and to continuous-time chains. Our approach yields a direct link between isoperimetric inequalities and heat kernel bounds; previously, this link rested on analytic estimates known as Nash inequalities.
Oscillations in propellant flames with edges

Abstract We examine the combustion of periodic sandwich propellants, alternating slices of ammonium perchlorate (AP) and binder. A fully-coupled combustion code, 2-D, unsteady, is used to examine the behavior for highly fuel-lean configurations for which the binder slice is thin, and the diffusion flame supported by binder gases and AP decomposition flame products generates but a small fraction of the gas-phase heat output. Under these circumstances, unexpected unsteady behavior—perhaps an instability—is uncovered and is described in detail for a pressure of 20 atm. It appears to arise partly because the AP decomposition flame has an edge and is quite distinct from the well-known instability that can arise in a 1-D flame (sans edge) supported by a homogeneous propellant.
System impacts of temperature-dependent transmission line models

This paper discusses system-level impacts of temperature-dependent transmission line models based on given ambient temperature profiles. In order to capture nonuniformity of line parameters caused by ambient temperature gradients, a line model characterized by multiple nonuniform segments is used. An automated tool has been developed to obtain appropriate system models, given a set of temperature measurements and their locations along each system branch. Using these models, the impacts of temperature variations are investigated with respect to line terminal behavior (bus voltage) and maximum power transfer characteristics. Results for the IEEE 30-bus test system are presented.
A metamaterial absorber for the terahertz regime: Design, fabrication and characterization

We present a metamaterial that acts as a strongly resonant absorber at terahertz frequencies. Our design consists of a bilayer unit cell which allows for maximization of the absorption through independent tuning of the electrical permittivity and magnetic permeability. An experimental absorptivity of 70% at 1.3 terahertz is demonstrated. We utilize only a single unit cell in the propagation direction, thus achieving an absorption coefficient α=2000 cm-1. These metamaterials are promising candidates as absorbing elements for thermally based THz imaging, due to their relatively low volume, low density, and narrow band response.
Strider: a black-box, state-based approach to change and configuration management and support

Abstract We describe a new approach, called Strider, to Change and Configuration Management and Support (CCMS). Strider is a black-box approach: without relying on specifications, it uses state differencing to identify potential causes of differing program behaviors, uses state tracing to identify actual, run-time state dependencies, and uses statistical behavior modeling for noise filtering. Strider is a state-based approach: instead of linking vague, high level descriptions and symptoms to relevant actions, it models management and support problems in terms of individual, named pieces of low level configuration state and provides precise mappings to user-friendly information through a computer genomics database. We use troubleshooting of configuration failures to demonstrate that the Strider approach reduces problem complexity by several orders of magnitude, making root-cause analysis possible.
The derived category with respect to a generator

Let \({\mathcal {G}}\) be any Grothendieck category along with a choice of generator \(G\), or equivalently a generating set \(\{G_i\}\). We introduce the derived category \({\mathcal {D}}(G)\), which kills all \(G\)-acyclic complexes, by putting a suitable model structure on the category \(\text {Ch}({\mathcal {G}})\) of chain complexes. It follows that the category \({\mathcal {D}}(G)\) is always a well-generated triangulated category. It is compactly generated whenever the generating set \(\{G_i\}\) has each \(G_i\) finitely presented, and in this case, we show that two recollement situations hold. The first is when passing from the homotopy category \(K({\mathcal {G}})\) to \({\mathcal {D}}(G)\). The second is a \(G\)-derived analog of a recollement due to Krause. We describe several examples ranging from pure and clean derived categories to quasi-coherent sheaves on the projective line.
Congruences for coefficients of modular functions

We examine canonical bases for weakly holomorphic modular forms of weight $$0$$ and level $$p = 2, 3, 5, 7, 13$$ with poles only at the cusp at $$\infty $$ . We show that many of the Fourier coefficients for elements of these canonical bases are divisible by high powers of $$p$$ , extending results of the first author and Andersen. Additionally, we prove similar congruences for elements of a canonical basis for the space of modular functions of level $$4$$ , and give congruences modulo arbitrary primes for coefficients of such modular functions in levels 1, 2, 3, 4, 5, 7, and 13.
Clinical Usefulness of Urinary Control Urethral Insert Devices

Urinary control urethral insert devices have been introduced as a non-surgical remedy to treat female urinary incontinence. Several early clinical trials have demonstrated the degrees of safety and efficacy, and have defined the morbidity and complications of these urethral inserts. This is a descriptive review of urethral insert devices in clinical use or currently undergoing clinical investigation.
Oligopolistic price competition and adverse price effect in online retailing markets

Abstract: The majority of theoretical vertical differentiation models in the literature derive equilibrium prices that exhibit what we call an ''adverse price effect:'' for a low quality firm, the equilibrium price may decrease when the product quality increases. This seemingly counterintuitive theoretical result has received little attention in the literature. In order to check whether this result is simply an artifact of model assumptions (such as a duopoly under absence of differentiation costs), we present an oligopoly model with a general cost structure, and derive closed-form solutions for two special cases. Our model shows that the adverse price effect continues to hold in a more general setting and we derive conditions under which such an adverse price effect occurs. We then attempt to find empirical evidence of this phenomenon using data from the online retailing (e-tailing) industry where e-tailers selling identical products mainly differentiate with their service offerings. Our analytical and empirical results offer guidelines to e-tailers on how to price their products and decide their service offerings. The results may also have implications for firms in other industries that are characterized by vertical differentiation.
Towards a framework for high-speed communication in a heterogeneous networking environment

The issues that are specific to heterogeneous networks are addressed. Some background on both the current ARPA internet model and high-speed packet switching is provided. This discussion includes: the internet components; the internet protocol hierarchy, popularly known as the transmission control protocol/internet protocol (TCP/IP) protocol suite; and the internet strengths and weaknesses. The major elements of an extended internet model that allows internetworking of new high-speed packet networks with a wide range of other networks, including current data networks and national telephone networks, are outlined. Some end-to-end and host interface issues are examined. >
On the growth of the Betti sequence of the canonical module

We study the growth of the Betti sequence of the canonical module of a Cohen–Macaulay local ring. It is an open question whether this sequence grows exponentially whenever the ring is not Gorenstein. We answer the question of exponential growth affirmatively for a large class of rings, and prove that the growth is in general not extremal. As an application of growth, we give criteria for a Cohen–Macaulay ring possessing a canonical module to be Gorenstein.
N-P pairing in nuclei

Variational wavefunctions for treating N-P pairing in the T=1 and T=0 channels are presented. Alpha-like correlations are explicitly included in the wavefunctions and arbitrary single-particle energy level spacings are allowed. A triple projection before variation procedure is used to obtain these wavefunctions. Taking a model system with equally spaced single-particle levels, several features of nuclei near the N=Z line are calculated. A new type of multiple degeneracy is found in nuclei near the N=Z line.
Topology of nonarchimedean analytic spaces and relations to complex algebraic geometry

This note surveys basic topological properties of nonarchimedean analytic spaces, in the sense of Berkovich, including the recent tameness results of Hrushovski and Loeser. We also discuss interactions between the topology of nonarchimedean analytic spaces and classical algebraic geometry.
Superconductivity in the rare-earth-free Tl–Ba–Cu–O system above liquid-nitrogen temperature

The initial discovery by Bednorz and Muller1 of 35-K superconductivity in the La-Ba-Cu-O system has stimulated worldwide activity in searching for higher-temperature superconductors. Elemental substitution has proved to be most effective in raising transition temperature. Substitution of Sr for Ba has produced 40-K superconductivity2–5and substitution of Y for La has produced a new high-temperature superconductor with transition temperature above liquid-nitrogen temperature6. A class of superconducting compounds of the form RBa2Cu307-x has been explored by further substitutions of other rare earths (Y is considered in the rare-earth [RI category here) for Y7-13. To date, a rare earth, an alkaline earth, copper and oxygen have been required for all high-temperature superconductors14,15. (Zhanget al 14reported 90-K superconductivity in the Th-Ba-Pb(Zr)-Cu-O system. Panetal15reported 50-K superconductivity in the Y-Ba-Ag-O system. As Th is a member of the actinide series which belongs to the same Group 3B in the periodic table as the lanthanide series and Ag belongs to the same Group 1B as Cu, high-temperature supercon-ductors are still thought to be closed in the Group 3B—Group 2A-Group 1B—oxygen system. ) Only partial substitutions ha. e led to superconductors, but with no significant rise of transition tem-perature (the only exception is 40-K superconductivity in La2CuO4-x , refs 16, 17). Here we report superconductivity in the rare-earth-free TI-Ba-Cu-O system. We have obsened sharp drops of resistance starting above 90 K with zero resistance at 81 K in this system. Magnetic measurements have confirmed that these sharp drops of resistance in the TI-Ba-Cu-O samples origi-nate from superconductivity. The samples are stable in air for at least two months, and their preparation is easily reproduced.
Synthesis of Polycyclic Nitrogen Heterocycles via Alkene Aminopalladation/Carbopalladation Cascade Reactions

A new method for the synthesis of tricyclic nitrogen heterocycles from N,2-diallylaniline derivatives is described. These transformations proceed via sequential alkene aminopalladation of an intermediate L(n)Pd(Ar)(NRR') species followed by alkene carbopalladation of the resulting L(n)Pd(Ar)(R) complex. Both alkene insertion steps occur in preference to C-N or C-C bond-forming reductive elimination. An unusual 1,3-palladium shift occurs when 2-Allyl-N-(2-vinylphenyl)aniline is employed as substrate, which yields a tetracyclic molecule with three contiguous stereocenters.
Nonequilibrium critical phenomena

Abstract We discuss the nonequilibrium critical phenomena in liquids, and the models for thesephenomena based on local equilibrium and extended scaling assumptions. Special situations areproposed for experimental tests of the theory. Near-critical steady and transient states are re-viewed.Inanear-criticalsteadystatecharacterizedbyatemperaturegradient,thetheorypredictsstrong nonequilibrium uctuations at very large length scales. Close to the critical point, thisresults in a nonlinear regime of heat conductivity. A transient nonequilibrium state triggeredby a rapid and large spatially uniform perturbation of the critical liquid is considered. A stepaway from criticality generates a free eld with strong and decaying correlations in initial state,while a step towards criticality initiates the increase of uctuations and of their correlation atthe large-scale edge of the critical range. The approach to equilibrium is characterized by anequilibration length eq that depends on time t. The theory predicts a power-law approach ofthe temperature to the new equilibrium; the new critical exponents depend on whether the tem-perature is initially increased or decreased.
Optimal Damped Vibration Absorber: Including Multiple Modes and Excitation Due to Rotating Unbalance

Optimal vibration absorbers are designed using the definition of H-infinity norm and numerical optimization. The cases of both constant amplitude excitation, and rotating unbalance excitation are considered. The design procedure is quite general, and can easily handle multiple modes of vibration. A general procedure to construct a root loci plot is also developed. Using a cantilever beam, numerical results are presented.Copyright © 2014 by ASME
Junction-temperature measurements in GaN UV light-emitting diodes using the diode forward voltage

A theoretical model for the dependence of the diode forward voltage (V/sub f/) on junction temperature (T) is developed. A new expression for dV/sub f//dT is derived that takes into account all relevant contributions to the temperature dependence of the forward voltage including the intrinsic carrier concentration, the bandgap energy, and the effective density of states. Experimental results on the junction temperature of GaN UV LEDs are presented. Excellent agreement between the theoretical and experimental temperature coefficient of the forward voltage (dV/sub f//dT) is found. The experimentally found linear dependence of the junction temperature on forward current is explained by a thermal conduction model. A thermal resistivity of 342.2 K/W is found for the UV LED.
Hyperstrong Radio-Wave Scattering in the Galactic Center. I. A Survey for Extragalactic Sources Seen Through the Galactic Center

The scattering diameters of Sgr A* and several nearby OH masers (≈ 1'' at 1 GHz) indicate that a region of enhanced scattering is along the line of sight to the Galactic center (GC). The scattering diameter of an extragalactic source seen through this scattering region will be larger by the ratio of the Sun-GC distance to the GC-scattering region separation. This ratio could be a factor of a few, if the scattering region is far from the GC and only a random superposition with it, to more than 100, if the scattering region is within the GC. We have used the VLA to survey 10 (11) fields at 20 cm (6 cm) that are between 7' and 137' from Sgr A*. Our objective was to identify extragalactic sources and measure their scattering diameters so as to constrain the GC-scattering region separation. In order to find sources within these fields, we have employed pdfCLEAN, a source detection algorithm in which sources are identified in an image by comparing the intensity histogram of the image to that expected from a noise-only image. We found over 100 sources, with the faintest sources being approximately 3 mJy. The average number of sources per field is approximately 10, though fields close to Sgr A* tend to contain fewer sources. In a companion paper we combine our survey with previous observations of the GC, and we assess the likelihood that the scattering region is so close to the GC that the resulting scattering diameters cause extragalactic sources to be resolved out by our observations. A number of Galactic sources are included in our source catalog. We discuss the double-lobed source 1LC 359.872+0.178, potentially an X-ray quiet version of 1E 1740.7-2942, a shell-like structure with a central point source, and a possible radio transient.
Catalytic C−H Amination for the Preparation of Substituted 1,2-Diamines

Rhodium-catalyzed C−H insertion of hydroxylamine-derived sulfamate esters makes possible the synthesis of unique oxathiadiazinane heterocycles, which upon mild reduction furnish differentially substituted 1,2-diamine products. This highly chemo- and diastereoselective transformation underscores the power of catalytic C−H functionalization as a general approach to C−N bond construction.
Stopping relativistic Xe, Ho, Au, and U nuclei in nuclear emulsions

Nuclei of /sub 54/Xe, /sub 67/Ho, /sub 79/Au, and /sub 92/U accelerated at the Lawrence Berkeley Laboratory Bevalac to energies between 1200 and 900 MeV/n have been stopped in nuclear emulsions. The observed residual ranges have been compared with those calculated from various models of energy loss and shown to be most consistent with a calculation that includes those higher-order correction terms proposed previously to describe the energy loss of highly charged particles, for which the first Born approximation is not valid.
Vertebrate faunas 49 to 36 million years ago and additions to the species of Leptoreodon (Mammalia: Artiodactyla) found in Texas

ABSTRACT A comparison of parts of the fossil mammalian faunas of southern California and western Texas with those of the northern Rocky Mountain states, combined with K/Ar dates, permits a division of the Duchesnean land-mammal age into early and late subages. The early Duchesnean fauna is more closely related to the Uintan and the late Duchesnean fauna is more closely related to that of the Chadronian. Leptoreodon major, L. pusillus, L. edwardsi, and L. leptolophus are recognized in late Eocene faunas of western Texas. A lower jaw fragment of L. leptolophus from the Laredo Formation, Claiborne Group, of the Texas Coastal Plain is described.
A Seyfert-2-like Spectrum in the High-mass X-Ray Binary Microquasar V4641 Sgr

We present an analysis of three archival Chandra observations of the black hole V4641 Sgr, performed during a decline into quiescence. The last two observations in the sequence can be modeled with a simple power law. The first spectrum, however, is remarkably similar to spectra observed in Seyfert-2 active galactic nuclei, which arise through a combination of obscuration and reflection from distant material. This spectrum of V4641 Sgr can be fit extremely well with a model including partial-covering absorption and distant reflection. This model recovers a Γ 2.0 power-law incident spectrum, typical of black holes at low Eddington fractions. The implied geometry is plausible in a high-mass X-ray binary like V4641 Sgr, and may be as compelling as explanations invoking Doppler-split line pairs in a jet, and/or unusual Comptonization. We discuss potential implications and means of testing these models.
Transacetalation: a convenient, nonaqueous method for effecting the deprotection of isopropylidene and benzylidene derivatives of sugars

Abstract Sugar isopropylidene and benzylidene derivatives can be readily deprotected under nonaqueous conditions by treatment of a dichloromethane solution of the protected sugar with an excess of a sacrificial glycol in the presence of a catalytic amount of p -toluenesulfonic acid. The reaction is conveniently monitored by GLC, and the fully or partially deprotected product precipitates from solution.
Magnetic fields and fractional statistics in boundary conformal field theory

Abstract We study conformal field theories describing two massless one-dimensional fields interacting at a single spatial point. The interactions we include are periodic functions of the bosonized fields separately plus a “magnetic” interaction that mixes the two fields. Such models arise in open-string theory and dissipative quantum mechanics and perhaps in edge state tunneling in the fractional quantized Hall effect. The partition function for such theories is a Coulomb gas with interchange phases arising from the magnetic field. These “fractional statistics” have a profound effect on the phase structure of the Coulomb gas. In this paper we present new exact and approximate results for this type of generalized Coulomb gas.
Chemical Evolution in Hierarchical Models of Cosmic Structure. I. Constraints on the Early Stellar Initial Mass Function

I present a new Galactic chemical evolution model motivated by and grounded in the hierarchical theory of galaxy formation, as expressed by a halo merger history of the Galaxy. This model accurately reproduces the metallicity distribution function (MDF) for Population II stars residing today in the Galactic halo. Model MDFs are calculated for a fiducial Galaxy formation scenario and a range of assumptions about the astrophysics of star formation and chemical enrichment at early times. The observed MDF and the apparent absence of true Population III stars from the halo strongly imply that there is some critical metallicity, Zcr 10-4 Z?, below which low-mass star formation is inhibited and perhaps impossible. The observed constraints from the halo MDF, relative metal abundances from extremely metal-poor Galactic halo stars, and the ionizing photon budget needed to reionize the IGM together imply a stellar IMF below Zcr that is peaked in the range of massive stars that experience core-collapse supernovae, with mean mass M = 8-42 M?. This mass range is similar to the masses predicted by models of primordial star formation that account for formation feedback. A set of five plausible IMF cases is presented, ranging from broadly peaked with mean mass ~15 M? to narrowly peaked at mean mass ~70 M?. These IMF cases cannot be distinguished formally by the available constraints, but the models with lower characteristic mass produce overall better fits to the available data. The model also implies that metal-poor halo stars below [Fe/H] -3 had only 1-10 metal-free stars as their supernova precursors, such that the relative abundances in these halo stars exhibit IMF-weighted averages over the intrinsic yields of the first supernovae. This paper is the first part of a long-term project to connect the high-redshift in situ indicators of early star formation with the low-z, old remnants of the first stars.
Combinatorial treatments enhance recovery following facial nerve crush

Objectives/Hypothesis: To investigate the effects of various combinatorial treatments, consisting of a tapering dose of prednisone (P), a brief period of nerve electrical stimulation (ES), and systemic testosterone propionate (TP) on improving functional recovery following an intratemporal facial nerve crush injury. Study Design: Prospective, controlled animal study. Methods: After a right intratemporal facial nerve crush, adult male Sprague-Dawley rats were divided into the following eight treatment groups: 1) no treatment, 2) P only, 3) ES only, 4) ES + P, 5) TP only, 6) TP + P, 7) ES + TP, and 8) ES + TP + P. For each group n = 4–8. Recovery of the eyeblink reflex and vibrissae orientation and movement were assessed. Changes in peak amplitude and latency of evoked response, in response to facial nerve stimulation, was also recorded weekly. Results: Brief ES of the proximal nerve stump most effectively accelerated the initiation of functional recovery. Also, ES or TP treatments enhanced recovery of some functional parameters more than P treatment. When administered alone, none of the three treatments improved recovery of complete facial function. Only the combinatorial treatment of ES + TP, regardless of the presence of P, accelerated complete functional recovery and return of normal motor nerve conduction. Conclusions: Our findings suggest that a combinatorial treatment strategy of using brief ES and TP together promises to be an effective therapeutic intervention for promoting regeneration following facial nerve injury. Administration of P neither augments nor hinders recovery. Laryngoscope, 2010
Preparation, electrochemical oxidation, and XPS studies of unsymmetrical ruthenocenes bearing the pentamethylcyclopentadienyl ligand

La reaction d'oligomere du dichloro(pentamethylcyclopentadienyl) ruthenium(III) avec des sels de metaux alcalins d'une variete de derives cyclopentadienyles fournit une voie d'acces a des ruthenocenes non symetriques
PCCI Control Authority of a Modern Diesel Engine Outfitted with Flexible Intake Valve Actuation

Premixed charge compression ignition (PCCI), an advanced mode combustion strategy, promises to simultaneously deliver the fuel efficiency of diesel combustion and the ultralow NO x emissions that usually require advanced exhaust aftertreatment. A flexible, computationally efficient, and whole engine simulation model for a 2007 6.7 l diesel engine with exhaust gas recirculation (EGR), variable geometry turbocharging (VGT), and common rail fuel injection was validated after extensive experimentation. This model was used to develop strategies for highly fuel-efficient and ultralow NO x emission PCCI. The primary aim of this modeling investigation is to determine the PCCI control authority present on a modern diesel engine outfitted with both conventional actuators (multi-pulse fuel injectors, EGR valve, and VGT) and flexible intake valve closure modulation, which dictates the effective compression ratio. The results indicate that early fuel injection coupled with ECR reduction and modest amounts of EGR yield a well-timed PCCI exhibiting 70% + reductions in NO x with no fuel consumption penalty over a significant portion of the engine operating range.
The synthesis of dithyreanitrile

Abstract An efficient synthesis of dithyreantrile ( 1 ), a novel insect antifeedant, is presented.
FEDRAM: A capacitor-less DRAM based on ferroelectric-gated field-effect transistor

A capacitor-less DRAM cell based on ferroelectric-gate memory transistor structure, FErroelectric-DRAM (FEDRAM), is introduced. Compared to the conventional DRAM cell, it offers much simpler cell structure, longer retention time, better scalability, and lower power consumption. Cell size of 4F 2 can be realized. It is also most suitable for embedded applications. Recent developments of the HfO 2 -based ferroelectrics have overcome the shortcomings of PZT and SBT for FEDRAM technology, and make the commercialization of FEDRAM much closer to reality.
Completeness of a relational calculus for program schemes

Abstract The relational calculus MU was presented in Willem-Paul de Roever's dissertation as a framework for describing and proving properties of programs. MU is axiomatized by de Roever in stages. The next-to-last stage is the calculus MU 2 , namely MU without the recursive μ -operator. Its axioms include typed versions of Tarski's axioms for the calculus of relations, together with axioms for the projection functions. For MU there is, in addition, an axiom expressing the least-fixed-point property of terms containing the μ -operator, and Scott's induction rule. Thus MU 2 is a calculus for nonrecursive program schemes. Around 1976 David Park conjectured that de Roever's axiomatization for MU 2 is complete. In this paper, we confirm Park's conjecture.
Integer cells in convex sets

Abstract Every convex body K in R n has a coordinate projection PK that contains at least vol ( 1 6 K ) cells of the integer lattice P Z n , provided this volume is at least one. Our proof of this counterpart of Minkowski's theorem is based on an extension of the combinatorial density theorem of Sauer, Shelah and Vapnik–Chervonenkis to Z n . This leads to a new approach to sections of convex bodies. In particular, fundamental results of the asymptotic convex geometry such as the Volume Ratio Theorem and Milman's duality of the diameters admit natural versions for coordinate sections.
Scattering of a plane acoustic wave by a spherical elastic shell near a free surface

Abstract The acoustic scattering by a submerged spherical elastic shell near a free surface, which is insonified by plane waves at arbitrary angles of incidence is analyzed in an exact fashion using the classical separation of variables technique. To satisfy the boundary conditions at the free surface as well as on the surface of the spherical elastic shell, the mathematical problem is formulated using the image method. The scattered wave fields are expanded in terms of the classical modal series of spherical wave functions utilizing the translational addition theorem. Quite similar to the problem of scattering by multiple spheres, numerical computation of the scattered wave pressure involves the solution of an ill-conditioned complex matrix system the size of which depends on how many terms of the modal series are required for convergence. This in turn depends on the value of the frequency, and on the proximity of the spherical elastic shell to the free surface. The ill-conditioned matrix equation is solved using the Gauss-Seidel iteration method and Twersky's method of successive iteration cross checking each other. Backscattered echoes from the spherical elastic shell are extensively calculated and displayed. The result also demonstrates that the large amplitude low frequency resonances of the echoes of the submerged elastic shell shift upward with proximity to the free surface. This can be attributed to the decrease of added mass for the shell vibration. The present benchmark solution could eventually be used to validate those found by numerical schemes.
Synthesis and biology of N-thiolated β-lactams

Abstract N-Thiolated β-lactams are an interesting new family of bioactive agents having antibacterial, antifungal, and anticancer capabilities. Our interest in these β-lactams stems from their highly unusual structure–activity profiles and selectivity toward only a few genera of pathogenic bacteria, including Staphylococcus aureus, Bacillus anthracis, and Micrococcus. Here, we provide a complete outline on our work in the discovery and ongoing development of these compounds, starting from our initial, unexpected finding of antimicrobial activity for one of the lead compounds, to a more complete understanding of their chemical and biological mode of action and potential utility as antibacterial compounds.
Institutions and Development in Latin America: A Comparative Analysis

We review the theoretical literature on the concept of institutions and its relationship to national development, propose a definition of the concept, and advance six hypotheses about institutional adequacy and contributions to national development. We then present results of a comparative empirical study of existing institutions in three Latin American countries and examine their organizational similarities and differences. Employing the qualitative comparative method (QCA) proposed by Ragin, we then test the six hypotheses. Results converge in showing the importance of meritocracy, immunity to corruption, absence of “islands of power,” and proactivity in producing effective institutions. Findings strongly support Peter Evans’ theory of developmental apparatuses.
Overview of K theory applied to strings

K-theory provides a framework for classifying Ramond-Ramond (RR) charges and fields. K-theory of manifolds has a natural extension to K-theory of noncommutative algebras, such as the algebras considered in noncommutative Yang-Mills theory or in open string field theory. In a number of concrete problems, the K-theory analysis proceeds most naturally if one starts out with an infinite set of D-branes, reduced by tachyon condensation to a finite set. This suggests that string field theory should be reconsidered for N=∞.
TIME DISCOUNTING FOR PRIMARY AND MONETARY REWARDS

This paper reports a positive and statistically significant relation between short-term discount rates elicited with a monetary and a primary reward (chocolate). The relation is most evident among people who like chocolate and are hungry. This finding suggests that high short-term discount rates are related to an underling individual trait, consistent with models of presentbiased preferences.
Disulfide formation via sulfenamides

A phosphine-mediated one-step disulfide formation from S-nitrosothiols has been developed. This reaction can convert unstable S-nitrosothiols to stable disulfidesviasulfenamide intermediates under very mild conditions. It has the potential to be used for the detection ofS-nitrosothiols.
OBSTRUCTION-FLAT ASYMPTOTICALLY LOCALLY EUCLIDEAN METRICS

We show that any asymptotically locally Euclidean (ALE) metric which is obstruction-flat or extended obstruction-flat must be ALE of a certain optimal order. Moreover, our proof applies to very general elliptic systems and in any dimension n ≥ 3. The proof is based on the technique of Cheeger–Tian for Ricci-flat metrics. We also apply this method to obtain a singularity removal theorem for (extended) obstruction-flat metrics with isolated C 0-orbifold singular points.
The promotion of unhealthy habits in gay, lesbian, and straight intimate partnerships

Abstract Health habits are linked to nearly half of U.S. and British deaths annually. While a legacy of research suggests that marriage has important positive consequences for health habits, recent work emphasizes that intimate ties can also deter from healthy habits and promote unhealthy habits. However, few studies examine the mechanisms through which unhealthy habits are promoted in marriage. Moreover, little research explores how unhealthy habits are promoted in intimate ties other than marriage—such as in gay and lesbian cohabiting relationships. The present study analyzes the mechanisms through which gay, lesbian, and straight long-term partners ( N = 120) contribute to one another's unhealthy habits. Three distinct mechanisms emerge. First, respondents identify a process of unilateral health habit diffusion wherein one partner's health habits directly influence the other partners' habits. Second, respondents describe bilateral unhealthy habit diffusion, wherein both partner's unhealthy habits are reinforced via mutual pleasure seeking or mutual failed motivation. Third, respondents describe a discourse of personal responsibility , wherein both partners purposefully fail to deter one another's unhealthy habits. Analysis further illustrates how these mechanisms operate differently for men and women in gay, lesbian, and straight relationships.
Full Spectral Survey of Active Galactic Nuclei in the Rossi X-ray Timing Explorer Archive

We have analyzed spectra for all active galactic nuclei (AGNs) in the Rossi X-ray Timing Explorer archive. We present long-term average values of absorption, Fe line equivalent width (EW), Compton reflection, and photon index, and calculate fluxes and luminosities in the 2-10 keV band for 100 AGN with sufficient brightness and overall observation time to yield high-quality spectral results. We compare these parameters across the different classifications of Seyferts and blazars. Our distributions of photon indices for Seyfert 1s and 2s are consistent with the idea that Seyferts share a common central engine; however, our distributions of Compton reflection hump strengths do not support the classical picture of absorption by a torus and reflection off a Compton-thick disk with type depending only on inclination angle. We conclude that a more complex reflecting geometry such as a combined disk and torus or clumpy torus is likely a more accurate picture of the Compton-thick material. We find that Compton reflection is present in ~85% of Seyferts and by comparing Fe line EW's to Compton reflection hump strengths we have found that on average 40% of the Fe line arises in Compton thick material; however, this ratio was not consistent from object to object and did not seem to be dependent on optical classification.
A novel reagent for the synthesis of geminal di-sulfones

Abstract A novel reagent (diisopropoxyphosphorylmethanesulfonylmethanesulfonylmethyl)-phosphonic acid diisopropyl ester ( 8 ) capable of forming symmetrical and non-symmetrical α,β unsaturated gem -disulfones is reported. Both aromatic and aliphatic aldehydes react in good yields to give exclusively the trans isomer. Selectivity for the mono-olefin can be achieved by varying the stoichiometry of reagents.