cssi/SciSciGPT-SciSciNet huggingface dataset:
New approaches to the asymmetric synthesis of non-proteinogenic α-amino acids and dipeptides through chiral β-lactam intermediates

Abstract Novel and effective routes to optically pure aromatic α-amino acids, α-methyl-α-amino acids and their derivatives including dipeptides are developed via homochiral β-lactams which are obtained through asymmetric [2+2] cycloadditions of ketenes to imines.
Controlled confinement and release of gases in single-walled carbon nanotube bundles.

A simple procedure is described that locks small quantities of SF6, CO2, and 13CO2 into opened single-walled carbon nanotube (SWNT) bundles and keeps the gas in the SWNTs above the desorption temperature of these molecules. The technique involves opening the SWNTs with ozonolysis at 300 K followed by vacuum-annealing at 700 K. Gases are then cryogenically adsorbed into the opened SWNTs and locked into the SWNT pores by functionalizing the sample with a low-temperature ozone treatment. The low-temperature ozone treatment functionalizes the entry ports into the SWNT pores, which in turn create a physical barrier for gases trying to desorb through these functionalized ports. The samples are stable under vacuum for periods of at least 24 h, and the trapped gases can be released by vacuum-heating to 700 K. Reduced quantities of the trapped gases remain in the SWNTs even after exposure to room air. Fourier transform infrared spectroscopy is used to monitor the functionalities resulting from the ozone treatment ...
Optimal Lower Bounds for Locality-Sensitive Hashing (Except When q is Tiny)

We study lower bounds for Locality-Sensitive Hashing (LSH) in the strongest setting: point sets in {0,1}d under the Hamming distance. Recall that H is said to be an (r, cr, p, q)-sensitive hash family if all pairs x, y ∈ {0,1}d with dist(x, y) ≤ r have probability at least p of collision under a randomly chosen h ∈ H, whereas all pairs x, y ∈ {0, 1}d with dist(x, y) ≥ cr have probability at most q of collision. Typically, one considers d → ∞, with c > 1 fixed and q bounded away from 0.For its applications to approximate nearest-neighbor search in high dimensions, the quality of an LSH family H is governed by how small its ρparameterρ = ln(1/p)/ln(1/q) is as a function of the parameter c. The seminal paper of Indyk and Motwani [1998] showed that for each c ≥ 1, the extremely simple family H = {x ↦ xi : i ∈ [d]} achieves ρ ≤ 1/c. The only known lower bound, due to Motwani et al. [2007], is that ρ must be at least ( e1/c - 1)/(e1/c + 1) ≥ .46/c (minus od(1)). The contribution of this article is twofold. (1) We show the “optimal” lower bound for ρ: it must be at least 1/c (minus od(1)). Our proof is very simple, following almost immediately from the observation that the noise stability of a boolean function at time t is a log-convex function of t. (2) We raise and discuss the following issue: neither the application of LSH to nearest-neighbor search nor the known LSH lower bounds hold as stated if the q parameter is tiny. Here, “tiny” means q = 2-Θ(d), a parameter range we believe is natural.
Worldsheet Descriptions of Wrapped NS Five-Branes

We provide a world-sheet description of Neveu-Schwarz five-branes wrapped on a complex projective space. It is an orbifold of the product of an Script N = 2 minimal model and the IR fixed point of a certain linear sigma model. We show how the naked singularity in the supergravity description is resolved by the world-sheet CFT. Applying mirror symmetry, we show that the low-energy theory of NS5-branes wrapped on Bbb CBbb P1 in Eguchi-Hanson space is described by the Seiberg-Witten prepotential for Script N = 2 super-Yang-Mills, with the gauge group given by the ADE-type of the five-brane. The world-sheet CFT is generically regular, but singularities develop precisely at the Argyres-Douglas points and massless monopole points of the space-time theory. We also study the low-energy theory of NS5-branes wrapped on Bbb CBbb P2 in a Calabi-Yau 3-fold and its relation to (2,2) super-Yang-Mills theory in two dimensions.
Statistical identifiability and convergence evaluation for nonlinear pharmacokinetic models with particle swarm optimization

The statistical identifiability of nonlinear pharmacokinetic (PK) models with the Michaelis-Menten (MM) kinetic equation is considered using a global optimization approach, which is particle swarm optimization (PSO). If a model is statistically non-identifiable, the conventional derivative-based estimation approach is often terminated earlier without converging, due to the singularity. To circumvent this difficulty, we develop a derivative-free global optimization algorithm by combining PSO with a derivative-free local optimization algorithm to improve the rate of convergence of PSO. We further propose an efficient approach to not only checking the convergence of estimation but also detecting the identifiability of nonlinear PK models. PK simulation studies demonstrate that the convergence and identifiability of the PK model can be detected efficiently through the proposed approach. The proposed approach is then applied to clinical PK data along with a two-compartmental model.
Dawn′s exploration of Vesta

Abstract On 16 July 2011, after completing nearly four years of interplanetary flight, Dawn entered orbit around (4) Vesta, the second most massive body in the main asteroid belt. Dawn used solar electric propulsion to spiral to six different orbits to accomplish its science campaign. Although the transfers to progressively lower orbits presented significant challenges, all were executed smoothly. During its nearly 14 months in orbit, Dawn spiraled down to 210 km above the surface and back up before initiating the gradual departure to travel to dwarf planet (1) Ceres for a 2015 rendezvous. Dawn′s exploration of Vesta has shown it to be geologically complex and fascinating, resembling terrestrial planets more than typical asteroids. Among the principal features is a 500-km-diameter impact basin within which is the second tallest mountain known in the solar system. This paper presents Dawn′s operations at Vesta and summarizes the principal findings.
Antipodal acoustic thermometry: 1960, 2004

Abstract On 21 March 1960, sounds from three 300-lb depth charges deployed at 5.5-min intervals off Perth, Australia were recorded by the SOFAR station at Bermuda. The recorded travel time of these signals, about 13,375 s, is a historical measure of the ocean temperature averaged across several ocean basins. The 1960 travel time measurement has about 3-s precision. High-resolution global ocean state estimates for 2004 from the “Estimating the Circulation and Climate of the Ocean, Phase II” (ECCO2) project were combined with ray tracing to determine the paths followed by the acoustic signals. The acoustic paths are refracted geodesics that are slightly deflected by either small-scale topographic features in the Southern Ocean or the coast of Brazil. The refractive influences of intense, small-scale oceanographic features, such as Agulhas Rings or eddies in the Antarctic Circumpolar Current, greatly reduce the necessary topographic deflection and cause the acoustic paths to meander in time. The ECCO2 ocean state estimates, which are constrained by model dynamics and available data, were used to compute present-day travel times. Measured and computed arrival coda were in good agreement. Based on recent estimates of warming of the upper ocean, the travel-time change over the past half-century was nominally expected to be about −9 s, but little difference between measured (1960) and computed (2004) travel times was found. Taking into account uncertainties in the 1960 measurements, the 2004 ocean state estimates, and other approximations, the ocean temperature averaged along the sound channel axis over the antipodal paths has warmed at a rate less than about 4.6 m °C yr−1 (95% confidence). At this time, the estimated uncertainties are comparable in size to the expected warming signal, however.
Complete intersection singularities of splice type as universal abelian covers

It has long been known that every quasi-homogeneous normal complex surface singularity with Q–homology sphere link has universal abelian cover a Brieskorn complete intersection singularity. We describe a broad generalization: First, one has a class of complete intersection normal complex surface singularities called “splice type singularities,” which generalize Brieskorn complete intersections. Second, these arise as universal abelian covers of a class of normal surface singularities with Q–homology sphere links, called “splice-quotient singularities.” According to the Main Theorem, splice-quotients realize a large portion of the possible topologies of singularities with Q–homology sphere links. As quotients of complete intersections, they are necessarily Q–Gorenstein, and many Q– Gorenstein singularities with Q–homology sphere links are of this type. We conjecture that rational singularities and minimally elliptic singularities with Q–homology sphere links are splice-quotients. A recent preprint of T Okuma presents confirmation of this conjecture. AMS Classification numbers Primary: 32S50, 14B05 Secondary: 57M25, 57N10
Extending simulation learning experiences to patients with chronic health conditions.

As articulated by the Institute of Medicine and reinforced by the recent health reform law, the United States is fostering a deliberate shift toward a more population-based approach to promoting health. Juxtaposed with this shift is the increasing number of persons in the United States with multiple chronic conditions. Thus, the opportunity has never been better and the demand has never been greater to identify and promote a key element of population-based health: supporting individuals and their family caregivers in the self-management of chronic health conditions.
Shape and vibration control of active laminated plates for RF and optical applications

Active shape and vibration control of large structures have long been desired for many practical applications. PVDF being one of the most suitable materials for these applications due to its strong piezoelectric properties and availability in thin sheets has been the focal point of most researchers in this area. Most of the research has been done to find an open loop solution, which would be able to shape the structure as per the desired requirements in an ideal atmosphere. Unmodeled dynamics and external disturbances prevent the open loop (no feedback) solution from achieving the desired shape. This research develops a dynamic model of a laminated plate consisting of two layers of PVDF film joined with a layer of epoxy. The orthotropic properties of PVDF have been modeled and the epoxy layer is considered to be isotropic. A general control model is developed, which would work for most boundary conditions and developed for a simply supported beam with patch actuators. The methodology is then extended for a simply supported laminated plate. This model could be used for real time dynamic disturbance rejection and shape and vibration control of the structure.
Eigenvalues and energy functionals with monotonicity formulae under Ricci flow

In this note, we construct families of functionals of the type of $${\mathcal{F}}$$ -functional and $${\mathcal{W}}$$ -functional of Perelman. We prove that these new functionals are nondecreasing under the Ricci flow. As applications, we give a proof of the theorem that compact steady Ricci breathers must be Ricci-flat. Using these new functionals, we also give a new proof of Perelman’s no non-trivial expanding breather theorem. Furthermore, we prove that compact expanding Ricci breathers must be Einstein by a direct method. In this note, we also extend Cao’s methods of eigenvalues (in Math Ann 337(2), 2007) and improve their results.
The generalized no-ghost theorem for N=2 SUSY critical strings

Abstract We prove the no-ghost theorem for the N=2 SUSY strings in (2, 2) dimensional flat Minkowski space. We propose a generalization of this theorem for an arbitrary geometry of the N=2 SUSY string theory taking advantage of the N=4 SCA generators present in this model. Physical states are found to be the highest weight states of the N=4 SCA.
Chemistry of aldolate dianions. β-Silyloxy silyl enol ethers as bifunctional nucleophilic equivalents for oxygen heterocycle synthesis

Abstract A variety of β-silyloxy silyl enol ethers ( 3 ) are easily produced by double deprotonation of readily available β-hydroxyketones. These substances undergo cyclization reactions with dioxenium cations to provide 2-alkoxy-tetrahydropyranones, thus confirming the use of 3 as bifuncfional reagents for oxygen heterocycle synthesis.
Error recovery through programming

The requirement for error recovery procedures has existed as long as computers themselves. Since the earliest computers, one of the goals of design has been to increase the reliability and availability of the computer to the user. While great strides have been made in this direction, the need of error recovery is still as present today as ever and at this time, the need is actually amplified and more pressing than ever before.
Chemical Synthesis of N-Aryl Glycosides

Along with the O- and C-aryl glycosides, N-aryl glycosides represent an important class of carbohydrate and heterocyclic aryl conjugates that possess diverse applications and implications of biological interest. However, most of the synthetic efforts have been directed toward the preparation of O- and C-aryl glycosides. This review focuses on the various strategies that have been employed to synthesize N-aryl glycosides, most of which developed in the past 20 years. Besides having their unique applications, these N-aryl glycosides can also be treated as the analogs of O- and C-aryl glycosides. Wide ranges of reaction conditions are discussed for the optimum conditions.
Estimation in the mixture of markov chains moving with different speeds

This article considers a new mixture of time-homogeneous finite Markov chains where the mixing is on the rate of movement and develops the EM algorithm for maximum likelihood estimation of the parameters of the mixture. Continuous- and discrete-time versions of the mixture are defined, and their estimation is considered separately. The developed methods are illustrated with an application to modeling bond ratings migration. The class of mixture models proposed in this article provides a framework for modeling population heterogeneity with respect to the rate of movement. The proposed mixture subsumes the mover–stayer model, which has been widely used in applications.
Demand shocks and the cyclical behavior of the real wage: Some international evidence

The focus of this investigation is on the cyclical response of the real wage to demand shocks. This response differentiates the empirical validity of major New Keynesian explanations of business cycles. The empirical evidence, across industrial countries, highlights a moderate positive correlation between nominal wage and price flexibility in response to various demand shocks. Nonetheless, higher price flexibility moderates the effect of demand shocks on real output, while higher nominal wage flexibility increases, or does not determine, the effects of demand shocks on real output across countries. An increase in the response of the real wage to demand shocks therefore exacerbates their real effect on output, as predicted by sticky-price models. Further, demand shocks do not determine the difference in wage variability. Nominal wage variability increases, in turn, output variability across countries. In contrast, demand shocks differentiate price variability. Price variability moderates, in turn, output variability across countries. JEL classification codes: E31, E32, E24
Higher order approximation of isochrons

Phase reduction is a commonly used techinque for analysing stable oscillators, particularly in studies concerning synchronization and phase lock of a network of oscillators. In a widely used numerical approach for obtaining phase reduction of a single oscillator, one needs to obtain the gradient of the phase function, which essentially provides a linear approximation of the local isochrons. In this paper, we extend the method for obtaining partial derivatives of the phase function to arbitrary order, providing higher order approximations of the local isochrons. In particular, our method in order 2 can be applied to the study of dynamics of a stable oscillator subjected to stochastic perturbations, a topic that will be discussed in a future paper. We use the Stuart–Landau oscillator to illustrate the method in order 2.
Numerical analysis of the non-uniform sampling problem

We give an overview of recent developments in the problem of reconstructing a band-limited signal from nonuniform sampling from a numerical analysis view point. It is shown that the appropriate design of the finite-dimensional model plays a key role in the numerical solution of the nonuniform sampling problem. In the one approach (often proposed in the literature) the finite-dimensional model leads to an ill-posed problem even in very simple situations. The other approach that we consider leads to a well-posed problem that preserves important structural properties of the original infinite-dimensional problem and gives rise to efficient numerical algorithms. Furthermore, a fast multilevel algorithm is presented that can reconstruct signals of unknown bandwidth from noisy nonuniformly spaced samples. We also discuss the design of efficient regularization methods for ill-conditioned reconstruction problems. Numerical examples from spectroscopy and exploration geophysics demonstrate the performance of the proposed methods.
Elliptical orbits in the Bloch sphere

As is well known, when an SU(2) operation acts on a two-level system, its Bloch vector rotates without change of magnitude. Considering a system composed of two two-level systems, it is proven that for a class of nonlocal interactions of the two subsystems including (with ) and the Heisenberg interaction, the geometric description of the motion is particularly simple: each of the two Bloch vectors follows an elliptical orbit within the Bloch sphere. The utility of this result is demonstrated in two applications, the first of which bears on quantum control via quantum interfaces. By employing nonunitary control operations, we extend the idea of controllability to a set of points which are not necessarily connected by unitary transformations. The second application shows how the orbit of the coherence vector can be used to assess the entangling power of Heisenberg exchange interaction.
Three-dimensional imaging in ultrasound

Ultrasonic three-dimensional images are constructed by “stacking” B-scan tomograms or ultrasonic CAT scans with a computer algorithm for subsequent perspective or sectional display. Perspective images of surfaces representing Doppler measurements of fluid velocity are illustrated in combination with isovelocity contours for flows through a flexible tube in vitro. Isospeed contours calculated from a dynamically moving epicardial surface are mapped onto the heart surface illustrating the combination of quantitative parametric data with a qualitative surface display. The efficacy of three-dimensional displays for increasing the information density and comprehensibility of pictoral representations of ultrasonic data sets is discussed.
Langmuir-Blodgettry of nanocrystals and nanowires.

Although nanocrystals and nanowires have proliferated new scientific avenues in the study of their physics and chemistries, the bottom-up assembly of these small-scale building blocks remains a formidable challenge for device fabrication and processing. An attractive nanoscale assembly strategy should be cheap, fast, defect tolerant, compatible with a variety of materials, and parallel in nature, ideally utilizing the self-assembly to generate the core of a device, such as a memory chip or optical display. Langmuir−Blodgett (LB) assembly is a good candidate for arranging vast numbers of nanostructures on solid surfaces. In the LB technique, uniaxial compression of a nanocrystal or nanowire monolayer floating on an aqueous subphase causes the nanostructures to assemble and pack over a large area. The ordered monolayer can then be transferred to a solid surface en masse and with fidelity. In this Account, we present the Langmuir−Blodgett technique as a low-cost method for the massively parallel, controlled ...
Relatedness in Trait Group Models of Social Evolution

Abstract Genetic relatedness is a central concept in the study of social evolution. Though originally defined in terms of genealogy, the modern version of relatedness accommodates genetic similarity of any origin. This paper examines relatedness in group structured modes, in which a trait affects the fitness of all group members. Such traits can be divided into two types, based on whether their group fitness effects encompass all group members including the actor (“whole-group traits”), or only group members other than the actor (“other-only traits”). Both trait types are common in nature as well as in theoretical models, but they have rarely been distinguished clearly. The average relatedness of recipients to actors differs for the two trait types within the same population and even the same individual, leading to different selection pressures and evolutionary outcomes. Total relatedness in group-structured models can be partitioned into two components: structural relatedness due to the size and number of groups in the population, and assortative relatedness due to the distribution of genotypes among groups. Each component differs for whole-group vs. other-only traits, both in terms of their values and the factors that influence them. Some key differences include: positive relatedness requires positive assortment for other-only but not for whole-group traits; negative relatedness is possible for other-only but not whole-group traits; relatedness depends on average group size for whole-group but not other-only traits, and non-random assortment into groups affects relatedness more strongly for other-only than whole-group traits. Recognizing the distinction between these trait types resolves some apparent contradictions in the literature, and clarifies the limits of some previous results.
The Origin of Soft X-rays in DQ Herculis

DQ Herculis (Nova Herculis 1934) is a deeply eclipsing cataclysmic variable containing a magnetic white dwarf primary. The accretion disk is thought to block our line of sight to the white dwarf at all orbital phases due to its extreme inclination angle. Nevertheless, soft X-rays were detected from DQ Her with ROSAT PSPC. To probe the origin of these soft X-rays, we have performed Chandra ACIS observations. We confirm that DQ Her is an X-ray source. The bulk of the X-rays are from a point-like source and exhibit a shallow partial eclipse. We interpret this as due to scattering of the unseen central X-ray source, probably in an accretion disk wind. At the same time, we detect weak extended X-ray features around DQ Her, which we interpret as an X-ray emitting knot in the nova shell.
Geometric phase in the classical continuous antiferromagnetic Heisenberg spin chain.

We show that the time evolution of a space curve is associated with a geometric phase. This phase arises from the path dependence of the rotation of the natural Frenet-Serret triad with respect to a nonrotating (Fermi-Walker) frame. We derive a general expression in 1+1 dimension for the phase and the associated gauge potential, and discuss the application of this formalism to the classical, continuous, antiferromagnetic Heisenberg spin chain.
On the Number of t-Ary Trees with a Given Path Length

We show that the number of t-ary trees with path length equal to p is $$\exp({{(\alpha {p}/{\log p})}(1+o(1))}),$$ where \(\alpha=h(t^{-1})t\log t\) and \(h(x)={-}x\log x {-}(1{-}x)\log (1{-}x).\) Besides its intrinsic combinatorial interest, the question recently arose in the context of information theory, where the number of t-ary trees with path length p estimates the number of universal types, or, equivalently, the number of different possible Lempel-Ziv '78 dictionaries for sequences of length p over an alphabet of size t.
On the nature of robot workspace

This paper demonstrates that workspace analysis is not merely a tool of volumetric analysis. In order to emphasize its broad implications in the configuration synthesis of robot manipulators, we use the term workspace theory. After re viewing some recent research on robot workspaces, it is shown that workspace theory leads to an anthropological observation in biomanipulation, qualitative transformations of holes and voids (central or toroidal), the geometric inversion method for the prediction of the number of solution sets, the existence of solution transition boundaries within the workspace (dex terous or total), and the influence oTjoint variable limits on the workspace and the multiplicity of solution sets.
Load sharing in tungsten fiber reinforced Kanthal composites

The load sharing in three tungsten fiber reinforced Kanthal matrix composites (with fiber volume fractions of 10, 20 and 30%) have been determined using in situ neutron diffraction measurements. The expected iso-strain region was limited in the 20 and 30% composites due to thermal residual stresses. The experimental data have been used to validate the predictions of a unit-cell finite element model. The model was able to accurately predict the measured in situ loading data for all three composites using the same material properties for all calculations.
A facile synthesis of 2,7‐diazapyrene

2,7-Diazapyrene is synthesized in three high-yield steps from commercially available 1,4,5,8-naphthalene tetracarboxylic dianhydride, which first reacts with concentrated ammonium hydroxide solution at room temperature to give 1,4,5,8-naphthalenetetracarboxylic diimide (96%). The latter compound is subsequently reduced with borane in refluxing tetrahydrofuran to give 1,2,3,6,7,8-hexahydro-2,7-diazapyrene (77%), which in turn is oxidized with manganese dioxide in refluxing benzene giving 2,7-diazapyrene (71%).
Euler solutions for an unbladed jet engine configuration

A Euler solution for an axisymmetric jet engine configuration without blade effects is presented. The Euler equations are solved on a multiblock grid which covers a domain including the inlet, bypass duct, core passage, nozzle, and the far field surrounding the engine. The simulation is verified by considering five theoretical properties of the solution. The solution demonstrates both multiblock grid generation techniques and a foundation for a full jet engine throughflow calculation.
Intramolecular variants of aminomethano desilylation: Reactions of in situ generated immonium ions with allylsilanes

Abstract Intramolecular condensation of immonium ions with allylsilanes in aqueous tetrahydrofuran at ambient temperature gives rise to five, six, seven, and eight-membered rings containing nitrogen.
A Principled Approach to Grammars for Controlled Natural Languages and Predictive Editors

Controlled natural languages (CNL) with a direct mapping to formal logic have been proposed to improve the usability of knowledge representation systems, query interfaces, and formal specifications. Predictive editors are a popular approach to solve the problem that CNLs are easy to read but hard to write. Such predictive editors need to be able to "look ahead" in order to show all possible continuations of a given unfinished sentence. Such lookahead features, however, are difficult to implement in a satisfying way with existing grammar frameworks, especially if the CNL supports complex nonlocal structures such as anaphoric references. Here, methods and algorithms are presented for a new grammar notation called Codeco, which is specifically designed for controlled natural languages and predictive editors. A parsing approach for Codeco based on an extended chart parsing algorithm is presented. A large subset of Attempto Controlled English has been represented in Codeco. Evaluation of this grammar and the parser implementation shows that the approach is practical, adequate and efficient.
Electron-transfer photochemistry of benzocyclobutenes stereospecific electrocyclic reactions of their cation radicals

The facile activation of cis- and trans-1,2-diphenylbenzocyclobutene (DBC) either by charge-transfer irradiation of the electron donor-acceptor complex with tetracyanoethylene or by chloranil photosensitization leads to a series of rapid [4 + 2] cycloadditions. The role of the cation radical DBC+. as the reactive intermediate which undergoes a stereospecific, conrotatory cycloreversion is delineated, especially with regard to “contact” and “solvent-separated” ion pairs. Such cycloadditions induced by electron transfer are discussed in the context of the thermal valence tautomerization of DBC previously established by Huisgen, Quinkert, and co-workers. Elektron-Transfer-Photochemie von Benzocyclobutenen. – Stereospezifische elektrocyclische Reaktionen ihrer Kation-Radikale Die leichte Aktivierung von cis- und trans-1,2-Diphenylbenzocyclobuten (DBC) entweder durch Bestrahlung der Charge-transfer-Verbindung mit Tetracyanethylen oder durch Photosensibilisierung mit Chloranil fuhrt zu einer Serie schneller [4 + 2]-Cycloadditionen. Die Rolle des Kationradikals DBC+. als reaktives Zwischenprodukt, das eine stereospezifische conrotatorische Cycloreversion eingeht, wird vorwiegend uber „Kontakt”- oder „Losungsmittel-getrennte” Ionen-Paare erklart. Solche Cycloadditionen, die durch einen Elektronentransfer eingeleitet werden, werden im Zusammenhang mit einer thermischen Valenztautomerie von DBC diskutiert, wie sie fruher von Huisgen, Quinkert und Mitarbeitern begrundet wurden.
Intra-aortic Balloon Counterpulsation as a ‘Bridge’ to Cardiac Transplantation: Effects in Nonischemic and Ischemic Cardiomyopathy

Intra-aortic balloon (IAB) counterpulsation has been utilized as an effective “bridge” to transplantation in patients with end-stage heart failure. To determine if patients with heart failure with nonischemic cardiomyopathy (NICM) derive the same benefit from IAB support as those with ischemic cardiomyopathy (ISCM), we evaluated 27 patients with NICM and 16 patients with ISCM who required IAB support while awaiting transplantation. Hemodynamic changes, effects on organ function (renal and hepatic), frequency of complications, and clinical outcomes were analyzed. Baseline demographics and hemodynamics were comparable in both groups (p=NS). Hemodynamics improved in both groups, immediately (15 to 30 min) following IAB insertion, with greater improvement (p
Bundling and Optimal Auctions of Multiple Products

We study the optimal (i.e. revenue maximizing) auction of multiple products. We make three major points. First, we extend the relationship between price discrimination and optimal auctions from the single-product case to the multiple-product case. A monopolist setting prices for multiple products may offer discounts on purchases of bundles of products; similarly, the optimal auction of multiple products facilitates price discrimination by allocating products inefficiently to customers who are willing to purchase both products. Second, we demonstrate that optimal auctions are qualitatively distinct from monopoly sales of multiple products. Because of uncertainty about the values of other consumers, two products are bundled probabilistically in an optimal auction for a customer who is willing to buy both of them. A customer may then receive a discount on a lower-valued product without receiving a higher-valued product. Third, we show that in an optimal auction of two products the allocation of one product may vary with the amount of competition for the other product.
Heavy-ion collisions: Direct and indirect probes of the density and temperature dependence of Esym

Heavy-ion collisions provide a versatile terrestrial probe of the nuclear equation of state through the formation of nuclear matter at a wide variety of temperatures, densities, and pressures. Direct and indirect approaches for constraining the density dependence of the symmetry energy using heavy-ion collisions have been developed. The direct approach relies on scaling methods which attempt to connect isotopic fragment distributions to the symmetry energy. Using the indirect approach constraints on the equation of state are extracted from comparison of experimental results and theoretical transport calculations which utilize effective nucleon-nucleon interactions. Besides exploring the density dependence of the equation of state, heavy-ion collisions are simultaneously probing different temperature gradients of nuclear matter allowing for the temperature dependence of the symmetry energy to be examined. The current progress and open questions related to constraining the density and temperature dependence of the symmetry energy with heavy-ion collisions are discussed in this paper.
Deltahedral Clusters in Neat Solids: Synthesis and Structure of the Zintl Phase Cs4Pb9 with Discrete Pb94- Clusters

Isolated clusters of Pb94- with the shape of monocapped square antiprisms are found in Cs4Pb9 made by direct fusion of the elements. A “close-packed” layer of clusters viewed along c of the monoclinic cell is shown to the right (b is vertical).
Requirement for Hydrogen-Bonding Cooperativity in Small Polyamides: A Combined VT-NMR and VT-IR Investigation.

A study of intramolecular hydrogen bonding in chloroform for a small combinatorial library of nine triamides with varying connecting chain length has been completed. The starting materials for the triamides are three diacids (succinic, glutaric, and adipic acid) and three amino acids (glycine, β-alanine, and γ-aminobutyric acid). The preferences for the head-to-tail type of folding pattern are identified for the smaller triamides (1 and 4). The preference for the head-to-tail folding pattern can be explained by the energetic superiority of an optimal hydrogen bond geometry in which the NH---O bond angle is near linearity. The β-alanine containing triamides 2, 5, and 8 are resistant to intramolecular hydrogen bonding, especially to nearest neighbor hydrogen bonding. At lower temperatures, triamides 2 and 5 exhibit a small population of head-to-tail type of folding, while triamide 8 shows a significant population of bifurcated conformation. Triamide 6, 7, and 9 prefer bicyclic structures involving nearest n...
On H. Alfvén's theory of the effect of magnetic storms on cosmic ray intensity☆

Abstract H. Alfven's theory envisages a stream of gas shot out from a place on the sun where there is a large magnetic field. The gas, supposed highly conducting, carries the magnetic field H with it, and the field is supposed to be perpendicular to the velocity v . A stationary observer observes an electric polarization perpendicular to H and v , and the potential change across the beam of width h is calculated as Hvh/C . A cosmic ray crossing the beam is supposed to change its energy by Hvhe/C , and by making H or h large this change of energy can be made as great as is desired. Alfven calculates a 10 per cent change for the energy of a 3 × 10 10 e.v. ray on crossing a beam of width 5 × 10 12 cm. carrying a magnetic field of 3 × 10 −4 gauss and travelling with a velocity of 2 × 10 8 cm./sec. The present paper recognizes that an observer moving with the beam observes no change of energy, and by a relativity transformation, it is shown that a fixed observer cannot observe a change of energy greater than 2 vW / C , where W is the energy of the cosmic ray. This change amounts to only about 1.4 per cent. The discrepancy between the conclusions from relativity and those drawn by Alfven are shown to arise from the fact that the cosmic ray path in the example considered by Alfven would have, in the beam, a radius of curvature 15 times smaller than the beam width and so could never cross it. Thus relativity gives for the change of energy of the beam an upper limit of the order 2 v / C times the energy of the beam, and this limit can never be exceeded, however large H or h may be chosen. An analysis of the considerations resulting from the assumption of a finite conductivity for the space external to the beam shows that the existence of such a conductivity does not change the conclusions.
Acyl Transfer Catalysis with 1,2,4-Triazole Anion

1,2,4-Triazole anion has been identified as an active acyl transfer catalyst suitable for the aminolysis and transesterification of esters.
Cutting the Gordian Knot: What can be done with the contaminated sediments in the Hudson Estuary and the New York Bight apex?

The sediments of the Hudson Estuary, along with its tributaries and embayments, are contaminated with heavy metals and organic compounds. These contaminants do not break down - or break down only very slowly - and may be toxic to, or may bioaccumulate in, estuary and marine organisms. The article looks at the coordinated efforts oc U.S. Army Corps of Engineers, the Port Authority of New York and New Jersey, and terminal operators to improve the almost-crisis situation.
Accelerated Curing of Silica-Fume Concrete

Silica fume is a common addition to high-performance concrete mix designs. The use of silica fume in concrete leads to increased water demand. For this reason, Florida Department of Transportation (FDOT) allows only a 72-h continuous moist cure process for concrete containing silica fume. Accelerated curing has been shown to be effective in producing high-performance characteristics at early ages in silica-fume concrete. However, the heat greatly increases the moisture loss from exposed surfaces, which may cause shrinkage problems. An experimental study was undertaken to determine the feasibility of steam curing of FDOT concrete with silica fume in order to reduce precast turn around time. Various steam-curing durations were utilized with small laboratory specimens. The concrete compressive strength, surface resistivity, and shrinkage were determined for various durations of steam curing. Results indicate that steam cured silica-fume concrete met all FDOT requirements for the 12, 18, and 24 h of curing periods. All steam cured samples demonstrated excellent durability up to 1 year of age. It was recommended that FDOT allow 12 h steam curing for concrete with silica fume.
Generalization of Schensted insertion algorithm to the cases of hooks and semi-shuffles

Given an rc-graph R of permutation w and an rc-graph Y of a permutation v, we provide an insertion algorithm which defines an rc-graph R ← Y in the case when v is a shuffle with the descent at r and w has no descents greater than r or in the case when v is a shuffle whose shape is a hook. This algorithm gives a combinatorial rule for computing the generalized Littlewood--Richardson coefficients cwvu in the two cases mentioned above.
Sailing research vessels and the Arctic schooner Bowdoin

In a long-range plan for ocean sciences, the National Science Foundation (NSF) recently emphasized a growing need for large research ships with global capabilities (Eos, October 1, 1985, p. 682). On a smaller scale, some research in coastal and shelf seas may benefit more from improved instruments than from grander vessels. A new generation of compact ocean instruments will encourage the use of ships of opportunity as effective alternatives to specialized ships with exotic facilities. In a curious mix, some of the new technology may be well matched with the unique capabilities of traditional sailing vessels.
Preparation of tetrazoles from organic nitriles and sodium azide in micellar media

An effective method for the preparation of 5-substituted tetrazoles from the corresponding nitriles in micellar media is described. It was demonstrated that almost quantitative yields of tetrazoles can be obtained if the amount of water-surfactant is optimized. The advantages of the methods presented over many others currently used are the simplicity, facility of isolation of tetrazole products and elimination of using relatively expensive solvents and reagents.
Close call at sea: Delaware's coastal zone act weathers a constitutional challenge

Abstract Delaware's Coastal Zone Act, in effect since 1971, has survived a recent constitutional challenge under the dormant Commerce Clause, brought by the Norfolk Southern Corporation. Norfolk Southern had sought to establish a coal transfer operation in the Delaware Bay, an activity that was found to be prohibited under the Coastal Zone Act. The Delaware law, which is incorporated into an approved coastal management program, prohibits new heavy industry and bulk product transfer facilities within the coastal zone. Whereas the U.S. Department of Commerce had approved the state's program, it chose to join Norfolk Southern as a “friend of the court.”; In the final decision, the law was upheld. However, the basis on which the decision was made raises some disturbing questions about the future of this and similar state coastal regulatory statutes. This paper presents a synopsis of the history of the case, followed by an in‐depth examination of the issues surrounding dormant Commerce Clause review, using the...
Quantum Barnes Function as the Partition Function of the Resolved Conifold

We give a short new proof of large duality between the Chern-Simons invariants of the 3-sphere and the Gromov-Witten/Donaldson-Thomas invariants of the resolved conifold. Our strategy applies to more general situations, and it is to interpret the Gromov-Witten, the Donaldson-Thomas, and the Chern-Simons invariants as different characterizations of the same holomorphic function. For the resolved conifold, this function turns out to be the quantum Barnes function, a natural -deformation of the classical one that in its turn generalizes the Euler gamma function. Our reasoning is based on a new formula for this function that expresses it as a graded product of -shifted multifactorials.
Minimal polynomials of singular moduli

Given a properly normalized parametrization of a genus-0 modular curve, the complex multiplication points map to algebraic numbers called singular moduli. In the classical case, the maps can be given analytically. However, in the Shimura curve cases, no such analytical expansion is possible. Fortunately, in both cases there are known algorithms for algebraically computing the rational norms of the singular moduli. We demonstrate a method of using these norm algorithms to algebraically determine the minimal polynomial of the singular moduli below a discriminant threshold. We then use these minimal polynomials to compute the algebraic $abc$-ratios for the singular moduli.
The data-text system: an application language for the social sciences

The enormous growth of special applications software has been the subject of much speculation and debate. While many of the developments are natural expansions into new application areas, many computer specialists argue that applications programming is a prime example of the tendency to reinvent the wheel. No area receives this accusation more than that of statistical packages or languages, particularly those developed for applications in the social and behavioral sciences. A recent study by Hugh F. Cline shows that in 130 universities which grant higher degrees in these fields, there are over 170 such packages or languages in use. This is more than one per university! No one could possibly maintain that all of these systems are unique; the duplication of effort has been rampant.
Sutured Heegaard diagrams for knots

We define sutured Heegaard diagrams for null-homologous knots in 3‐manifolds. These diagrams are useful for computing the knot Floer homology at the top filtration level. As an application, we give a formula for the knot Floer homology of a Murasugi sum. Our result echoes Gabai’s earlier works. We also show that for socalled “semifibred" satellite knots, the top filtration term of the knot Floer homology is isomorphic to the counterpart of the companion. 57R58, 57M27; 53D40
Novel triarylimidazole redox catalysts: synthesis, electrochemical properties, and applicability to electrooxidative C-H activation.

A new class of metal-free, easy to synthesize redox catalysts based on a triarylimidazole framework is described. With those synthesized thus far, one can access a potential range of ca. 410 mV. They proved to be useful mediators for the activation of benzylic C–H bonds under mild conditions.
Highlights of non-equilibrium, non-isobaric, non-isothermal desorption of nitrogen from a LiX zeolite column by rapid pressure reduction and rapid purge by oxygen

The effects of adsorption kinetics, column pressure drop, gas phase mass and heat dispersions, gas–solid heat transfer resistance, and adsorber adiabaticity on desorption of N2 from a LiX zeolite column by O2 purge as well as pressurization–depressurization of the column using pure N2 were recently studied using a numerical model of these processes [Chai et al. in Ind Eng Chem Res 50:8703, 2011, Chai et al. in Adsorption 18:87, 2012, Chai et al. in AIChE J 59:365 2013; Rama Rao et al. in Adsorption 2013]. The role of adsorbent particle size and column length to diameter ratio in determining the durations and efficiency of these processes were also investigated. These studies revealed several important limiting and optimum conditions for optimum operation of these processes which can be useful in design of a practical rapid pressure swing adsorption (RPSA) process for medical oxygen concentrator (MOC) application. The purpose of this short review article is to consolidate and re-emphasize these important results in a single article to be used as a guideline for design of a RPSA-MOC unit.
Star Formation Thresholds and Galaxy Edges: Why and Where

We study global star formation thresholds in the outer parts of galaxies by investigating the stability of disk galaxies embedded in dark halos. The disks are self-gravitating, contain metals and dust, and are exposed to UV radiation. We find that the critical surface density for the existence of a cold interstellar phase depends only weakly on the parameters of the model and coincides with the empirically derived surface density threshold for star formation. Furthermore, it is shown that the drop in the thermal velocity dispersion associated with the transition from the warm to the cold gas phase triggers gravitational instability on a wide range of scales. The presence of strong turbulence does not undermine this conclusion if the disk is self-gravitating. Models based on the hypothesis that the onset of thermal instability determines the star formation threshold in the outer parts of galaxies can reproduce many observations, including the threshold radii, the column densities, and the sizes of stellar disks as a function of disk scale length and mass. Finally, prescriptions are given for implementing star formation thresholds in (semi-)analytic models and three-dimensional hydrodynamical simulations of galaxy formation.
The development cycle of a pharmaceutical discovery chemi-informatics system.

The rate at which we now produce, test, and warehouse new compound structures in the Discovery process strains our ability to evaluate and comprehend the information that results [Fayyad U. Database Programming and Design 1998;11(3):24]. With the advent of robotic systems and specialized software tools, the profusion of data yielded by the pharmaceutical discovery process is testing the manageability and usefulness of the information resource. Clearly, the challenge faced by Discovery today lies not in the generation of data, but in the generation of software tools that provide the means to store, extract, analyze, and display the data contained within the this expanding resource, and thereby meet the needs of the disciplines participating in the Discovery process. In this review a schematic of a chemi-informatics system, that aids our adaptation to the evolving Discovery process and the expanded flow of pharmaceutical data, is discussed. © 1999 John Wiley & Sons, Inc. Med Res Rev, 19, No. 3, 209–221,1999.