cssi/SciSciGPT-SciSciNet huggingface dataset:
Ion Stability in Bunched Electron Beams

Accumulation of ions can adversely affect the performance of an electron storage ring. Stability of ion motion under the influence of passing bunches is often used to predict if ion accumulation will occur in a particular storage ring design. This stability question has been previously studied with a linear model. We present a nonlinear numerical tool to study ion motion in a beam of short bigaussian electron bunches. Results of ion trapping studies on a model electron storage ring are presented. We find that including nonlinear effects may not significantly alter the conclusions of the linear model, and that in a ring containing many bunches a gap in the bunch train effectively destabilizes ion motion.
Application of structured singular value synthesis to a fighter aircraft

The results of a design study to examine the control of a fighter aircraft at high angles of attack are presented. The flight condition considered represents an extreme point along a demanding large angle maneuver. Control laws are developed for a linear model of the aircraft using structure singular value synthesis to take the parameter uncertainty structure into account. The control objective is to attain acceptable flying qualities despite variations and uncertainty in the aircraft's aerodynamic coefficients. Desired flying qualities are embedded in ideal models of the angle of attack, sideslip angle, and stability axis roll rate responses to pilot inputs. The control objective is met by minimizing the weighted error between the ideal model outputs and the plant outputs while including structured parameter uncertainty in the design model.
Gold-Catalyzed Hydroamination of C–C Multiple Bonds

The development of general and efficient methods for the addition of an N–H bond across a C–C multiple bond (hydroamination) represents a significant challenge in both organic synthesis and homogeneous catalysis. Although a diverse range of transition-metal complexes have been employed as catalysts for hydroamination, examples of gold-catalyzed hydroamination were exceedingly rare prior to 2001. However, over the past five years gold complexes have been applied as catalysts for a number of selective organic transformations including the hydroamination of unactivated alkenes, alkynes, allenes, and 1,3-dienes. This Microreview provides a brief overview of the gold-catalyzed hydroamination of C–C multiple bonds. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Taking Heinz Private: Managing Value Realization Risk

On February 14, 2013, it was announced that Heinz was being taken private by Berkshire Hathaway and their Brazilian private equity partner, 3G Capital, at a price approximately 20% higher than Heinz’s February 13, 2013, stock price—which was eight times Heinz’s book value. To assess this deal’s price, we employ the modern Graham and Dodd valuation approach, a school of thought with which Warren E. Buffett has long been affiliated. This approach sheds significant light on this deal’s risks and value. How to manage these risks, specifically with respect to value realization, is explored via deal terms and conditions and rigorous post-deal operational management. Given low interest rates and the resulting higher valuations, our findings on joint contractual and operational value realization risk management could prove useful to future private equity acquirers.
Hidden identity-based signatures

This study introduces hidden identity-based signatures (Hidden-IBS), a type of digital signatures that provide mediated signer-anonymity on top of Shamir's identity-based signatures. The motivation of the new signature primitive is to resolve an important issue with the kind of anonymity offered by ‘group signatures’ where it is required that either the group membership list be public for opening signatures or that the opening authority be dependent on the group manager for its operation. Contrary to this, Hidden-IBS does not require the maintenance of a group membership list for opening signatures and they enable an opening authority that is totally independent of the group manager. As the authors argue this makes Hidden-IBS much more attractive than group signatures for a number of applications. In this study, the authors provide a formal model of Hidden-IBS as well as two efficient constructions that realise the new primitive. To demonstrate the power of the new primitive, the authors apply it to solve a problem of current onion-routing systems focusing on the Tor system in particular.
Dynamic optimization without dynamic programming

Abstract To solve a multiperiod optimization problem with a differentiable and concave objective function and a differentiable function for the dynamic process, this paper suggests an alternative to dynamic programming. It extends the method of Lagrange multipliers and Pontryagin's maximum principle to the stochastic case and proposes to solve for a Lagrangian function rather than the value function in dynamic programming. Since the value function is a solution to the partial differential equations given by the Lagrange functions, the method proposed is analytically simpler and computationally more efficient. Numerical methods of optimization using Lagrange multipliers and an illustrative example from the study of real business cycles are provided.
Coming alive in school math and beyond

In spite of ever-increasing efforts, the failure of schools to help children learn mathematics in a relevant and useful manner continues. We know that the enforced rote learning is a direct cause of this, so we try to promote better teaching methods. But having given up on the children, believing most of them incapable, we continue teaching everything with drill and testing, thus ensuring the continued rote learning and confirming our beliefs. Thus the children's power of thought, vitality and responsibility remain wiped out.
Nanophotonic interconnection networks for performance-energy optimized computing

As computing performance continues to grow through the increasing number of processing cores, the interconnection network has become the central subsystem for providing the communications infrastructure. Electronic interconnects are increasingly bound by the associated power dissipation of high-bandwidth data movement. Recent advances in chip-scale silicon photonic technologies have created the potential for developing optical interconnects that can offer highly energy efficient communications. This talk will examine the design and performance of photonic networks-on-chip architectures that support both on-chip and memory access communication in an energy efficient manner.
Dynamic response of dielectric elastomers

Abstract Dielectric elastomers have received a great deal of attention recently for effectively transforming electrical energy to mechanical work. Their large strains and conformability make them enticing materials for many new types of actuators. Unfortunately, their non-linear material behavior and large deformations make actual devices difficult to model. However, the reason for this difficulty can also be used to design actuators that utilize these material and geometric non-linearities to obtain multiple stable equilibria. In this work, we investigate one of the simplest possible configurations, a spherical membrane, using a model that incorporates both mechanical and electrostatic pressure as well as inertial effects that become important when transitioning from one equilibrium to another.
LiOOt-Bu as a terminal oxidant in a titanium alkoxide-mediated [2+2+2] reaction cascade

Abstract LiOO t -Bu is an effective oxidant for converting the penultimate organometallic intermediate generated in a titanium alkoxide-mediated [2+2+2] reaction cascade to an allylic alcohol. Oxidation of the presumed allylic titanium species is highly regioselective, providing direct access to substituted hydrindanes containing a primary allylic alcohol. In addition to demonstrating the feasibility of this oxidation process, we document the ability to convert the primary allylic alcohol products to angularly substituted cis -fused hydrindanes.
Enhanced Cooperativity in Hydrolytic Kinetic Resolution of Epoxides using Poly(styrene) Resin‐Supported Dendronized Co‐(Salen) Catalysts

Excellent enantioselectivities and isolated yields have been achieved for the hydrolytic kinetic resolution of epoxides using a resin-supported dendronized R,R-(salen)Co catalyst with catalyst loadings as low as 0.04 mol%, the lowest metal loadings of any heterogeneous resin-supported (salen)Co catalyst reported to date. In addition, the supported catalysts can be recycled and reused with comparable enantioselectivities. It is hypothesized that the high catalytic activity can be attributed to the flexible linker and the dendronized framework supporting the (salen)Co moieties on the resin thereby promoting cooperativity between two metal centers. This work opens up new opportunities for the design of highly active resin-supported catalysts that catalyze transformations through a bimetallic pathway.
Radical Deoxygenation of Hydroxyl Groups via Phosphites

A highly efficient, two-step sequence method for the deoxygenation of hydroxyl groups has been developed. The method involves the preparation of the 2-(2-iodophenyl)ethyl methyl phosphite derivative of an alcohol using methyl dichlorophosphite and 2-(2-iodophenyl)ethanol. Treatment of the phosphite intermediate with (n-Bu)3SnH/AIBN in refluxing benzene cleanly produces the deoxygenation product of the original alcohol.
Charged Higgs boson production in bottom-gluon fusion

We compute the complete next-to-leading order SUSY-QCD corrections for the associated production of a charged Higgs boson with a top quark via bottom-gluon fusion. We investigate the applicability of the bottom parton description in detail. The higher order corrections can be split into real and virtual corrections for a general two Higgs doublet model and into additional massive supersymmetric loop contributions. We find that the perturbative behavior is well under control. The supersymmetric contributions consist of the universal bottom Yukawa coupling corrections and nonfactorizable diagrams. Over most of the relevant supersymmetric parameter space the Yukawa coupling corrections are sizable, while the remaining supersymmetric loop contributions are negligible.
Managerial Legal Liability Coverage and Earnings Conservatism

Abstract This paper examines the effect of managerial legal liability coverage on earnings conservatism. Using directors’ and officers’ (D&O) liability insurance coverage and cash for indemnification as a proxy for managerial legal liability coverage, we find that the higher the managerial liability coverage, which reduces the expected legal liability of managers, the less conservative the firm's earnings. We also find that managerial legal liability coverage has a stronger influence on earnings conservatism in a legal regime with higher litigation risk. Our results are consistent with the threat of litigation conditioning managers to practice conservative accounting.
Consistent sphere reductions and universality of the Coulomb branch in the domain-wall/QFT correspondence

Abstract We prove that any D -dimensional theory comprising gravity, an antisymmetric n -index field strength and a dilaton can be consistently reduced on S n in a truncation in which just n scalar fields and the metric are retained in ( D − n )-dimensions, provided only that the strength of the coupling of the dilaton to the field strength is appropriately chosen. A consistent reduction can then be performed for n ≤5; with D being arbitrary when n ≤3, whilst D ≤11 for n =4 and D ≤10 for n =5. (Or, by Hodge dualisation, n can be replaced by ( D − n ) in these conditions.) We obtain the lower-dimensional scalar potentials and construct associated domain wall solutions. We use the consistent reduction ansatz to lift domain-wall solutions in the ( D − n )-dimensional theory back to D dimensions, where we show that they become certain continuous distributions of ( D − n −2)-branes. We also examine the spectrum for a minimally-coupled scalar field in the domain-wall background, showing that it has a universal structure characterised completely by the dimension n of the compactifying sphere.
Elastic scattering and energy theorems for a doubly periodic planar array of elastic obstacles.

Mixed vector-dyadic equations derived earlier [V. Twersky, J. Math. Phys. 16, 633 (1973)] for multiple scattering of elastic waves are applied to a doubly periodic planar array of elastic obstacles. Different approximations for the multiple-scattering wave and amplitudes are given. Three groups of four energy theorems are discussed. Results for identical rigid elastic scatterers are derived
RESOLVING THE FORMATION OF PROTOGALAXIES. I. VIRIALIZATION

Galaxies form in hierarchically assembling dark matter halos. With cosmological three dimensional adaptive mesh refinement simulations, we explore in detail the virialization of baryons in the concordance cosmology, including optically thin primordial gas cooling. We focus on early protogalaxies with virial temperatures of 10 4 K and their progenitors. Without cooling, virial heating occurs in shocks close to the virial radius for material falling in from voids. Material in dense filaments penetrates deeper to about half that radius. With cooling the virial shock position shrinks and also the filaments reach scales as small as a third the virial radius. The temperatures in protogalaxies found in adiabatic simulations decrease by a factor of two from the center and show flat entropy cores. In cooling halos the gas reaches virial equilibrium with the dark matter potential through its turbulent velocities. We observe turbulent Mach numbers ranging from one to three in the cooling cases. This turbulence is driven by the large scale merging and interestingly remains supersonic in the centers of these early galaxies even in the absence of any feedback processes. The virial theorem is shown to approximately hold over 3 orders of magnitude in length scale with the turbulent pressure prevailing over the thermal energy. The turbulent velocity distributions are Maxwellian and by far dominate the small rotation velocities associated with the total angular momentum of the galaxies. Decomposing the velocity field using the Cauchy-Stokes theorem, we show that ample amounts of vorticity are present around shocks even at the very centers of these objects. In the cold flow regime of galaxy formation for halo masses below 10 12 M⊙, this dominant role of virialization driven turbulence should play an important role in for star formation as well as the build up of early magnetic fields. Subject headings: Cosmology: high-redshift—galaxy formation—star formation
Conceptual design of a flight validation mission for a Hypervelocity Asteroid Intercept Vehicle

Abstract Near-Earth Objects (NEOs) are asteroids and comets whose orbits approach or cross Earth׳s orbit. NEOs have collided with our planet in the past, sometimes to devastating effect, and continue to do so today. Collisions with NEOs large enough to do significant damage to the ground are fortunately infrequent, but such events can occur at any time and we therefore need to develop and validate the techniques and technologies necessary to prevent the Earth impact of an incoming NEO. In this paper we provide background on the hazard posed to Earth by NEOs and present the results of a recent study performed by the NASA/Goddard Space Flight Center׳s Mission Design Lab (MDL) in collaboration with Iowa State University׳s Asteroid Deflection Research Center (ADRC) to design a flight validation mission for a Hypervelocity Asteroid Intercept Vehicle (HAIV) as part of a Phase 2 NASA Innovative Advanced Concepts (NIAC) research project. The HAIV is a two-body vehicle consisting of a leading kinetic impactor and trailing follower carrying a Nuclear Explosive Device (NED) payload. The HAIV detonates the NED inside the crater in the NEO׳s surface created by the lead kinetic impactor portion of the vehicle, effecting a powerful subsurface detonation to disrupt the NEO. For the flight validation mission, only a simple mass proxy for the NED is carried in the HAIV. Ongoing and future research topics are discussed following the presentation of the detailed flight validation mission design results produced in the MDL.
TIRE TRACK GEOMETRY: VARIATIONS ON A THEME

We study closed smooth convex plane curves Λ enjoying the following property: a pair of pointsx, y can traverse Λ so that the distances betweenx andy along the curve and in the ambient plane do not change; such curves are calledbicycle curves. Motivation for this study comes from the problem how to determine the direction of the bicycle motion by the tire tracks of the bicycle wheels; bicycle curves arise in the (rare) situation when one cannot determine which way the bicycle went.
On the Existence of Absolutely Simple Abelian Varieties of a Given Dimension over an Arbitrary Field

Abstract We prove that for every field k and every positive integer n there exists an absolutely simple n -dimensional abelian variety over k . We also prove an asymptotic result for finite fields: For every finite field k and positive integer n , we let S ( k , n ) denote the fraction of the isogeny classes of n -dimensional abelian varieties over k that consist of absolutely simple ordinary abelian varieties. Then for every n we have S ( F q , n )→1 as q →∞ over the prime powers.
A Dynamic Theory of Resource Wars

We develop a dynamic theory of resource wars and study the conditions under which such wars can be prevented. Our focus is on the interaction between the scarcity of resources and the incentives for war in the presence of limited commitment. We show that a key parameter determining the incentives for war is the elasticity of demand. Our first result identifies a novel externality that can precipitate war: price-taking firms fail to internalize the impact of their extraction on military action. In the case of inelastic resource demand, war incentives increase over time and war may become inevitable. Our second result shows that in some situations, regulation of prices and quantities by the resource-rich country can prevent war, and when this is the case, there will also be slower resource extraction than the Hotelling benchmark (with inelastic demand). Our third result is that because of limited commitment and its implications for armament incentives, regulation of prices and quantities might actually precipitate war even in some circumstances where wars would not have arisen under competitive markets. Copyright 2012, Oxford University Press.
Identification and Characterization of a Mammalian 39-kDa Poly(ADP-ribose) Glycohydrolase

ADP-ribosylation is a post-translational modification resulting from transfer of the ADP-ribose moiety of NAD to protein. Mammalian cells contain mono-ADP-ribosyltransferases that catalyze the formation of ADP-ribose-(arginine) protein, which can be cleaved by a 39-kDa ADP-ribose-(arginine) protein hydrolase (ARH1), resulting in release of free ADP-ribose and regeneration of unmodified protein. Enzymes involved in poly(ADP-ribosylation) participate in several critical physiological processes, including DNA repair, cellular differentiation, and carcinogenesis. Multiple poly(ADP-ribose) polymerases have been identified in the human genome, but there is only one known poly(ADP-ribose) glycohydrolase (PARG), a 111-kDa protein that degrades the (ADP-ribose) polymer to ADP-ribose. We report here the identification of an ARH1-like protein, termed poly(ADP-ribose) hydrolase or ARH3, which exhibited PARG activity, generating ADP-ribose from poly-(ADP-ribose), but did not hydrolyze ADP-ribose-arginine, -cysteine, -diphthamide, or -asparagine bonds. The 39-kDa ARH3 shares amino acid sequence identity with both ARH1 and the catalytic domain of PARG. ARH3 activity, like that of ARH1, was enhanced by Mg(2+). Critical vicinal acidic amino acids in ARH3, identified by mutagenesis (Asp(77) and Asp(78)), are located in a region similar to that required for activity in ARH1 but different from the location of the critical vicinal glutamates in the PARG catalytic site. All findings are consistent with the conclusion that ARH3 has PARG activity but is structurally unrelated to PARG.
Destruction of the pinnae of white mice by high intensity air-borne sound.

The pinnae of white mice, when exposed to high intensity airborne sound waves, exhibit an immediate inflammation followed by degeneration. Treated pinnae were compared histologically with normal pinnae, with pinnae treated with high temperatures, and with pinnae of mice which were depilated around the ears and treated with sound so that no heat could be produced by absorption of sound in the fur. The results showed that the major factor in destruction of the pinnae is heating in the fur, but some of the effects produced by sound are probably the results of mechanical agitation or a combination of heating and mechanical agitation.
Demand Reduction from Plain and Pictorial Cigarette Warning Labels: Evidence from Experimental Auctions

We report the results of experimental auctions with U.S. smokers, assessing the percentage of U.S. smokers whose demand for cigarettes decreases when bidding on packs with text and pictorial warnings, relative to packs with text-only warnings. We find that pictorial labels and pictorial labels accompanied by plain packaging are more effective at reducing demand for cigarettes than only a front text warning label. We also find that pictorial labels were most effective at encouraging younger smokers to reduce their demand for cigarettes, and plain packaging was most effective at reducing demand among less educated smokers. Copyright 2013, Oxford University Press.
Solvothermal synthesis of nanocrystalline copper nitride from an energetically unstable copper azide precursor.

Nonaqueous solvothermal chemical reactions have found extensive utility in the growth of inorganic non-oxide materials. This report describes the successful use of organic solvothermal environments to synthesize energetically unstable copper azide precursors that are then decomposed in situ to crystalline metastable copper nitride at temperatures below 200 °C. A comparison of Cu3N products formed from nonpolar (toluene) and coordinating (THF) solvents is described. The cubic Cu3N products are nanocrystalline with aggregated particle-like extended structures and were characterized by X-ray diffraction, electron microscopy, IR spectroscopy, and mass spectrometry. The thermal stability and composition of Cu3N was examined by thermogravimetric analysis and bulk elemental analysis. The particle surfaces contain bound residual solvent species that can be removed by heating. The poorly coordinating solvent, toluene, lead to a more crystalline product containing less residual organic content. Benchtop reactions w...
Spam and Beyond: An Information-Economic Analysis of Unwanted Commercial Messages

The phenomenon of unwanted commercial messages (UCM), including e-mail spam and emerging forms that target other Internet communications facilities, is analyzed from an information-economics perspective. UCM traffic pays off for its senders when it is noticed and consumed by Internet users; the industry is, therefore, dependent on a common-pool resource that is accessed through an information asset. An analytical model of the industry is derived and solved computationally, and two dimensions of information quality held by the senders of UCM traffic are manipulated in the model. It is shown that such manipulations can moderate over time both the number of UCM campaigns undertaken and the amount of Internet bandwidth consumed by UCM. Manipulations of the information-quality dimensions affected by e-mail filtering reduce the amount of traffic that penetrates an Internet user's attention space but increase the amount of Internet bandwidth consumed. This is consistent with data reported by e-mail security prov...
Application of Measured Loads to Wind Turbine Fatigue and Reliability Analysis

Cyclic loadings produce progressive damage that can ultimately result in wind turbine structural failure. There are many issues that must be dealt with in turning load measurements into estimates of component fatigue life. This paper deals with how the measured loads can be analyzed and processed to meet the needs of both fatigue life calculations and reliability estimates. It is recommended that moments of the distribution of rainflow-range load amplitudes be calculated and used to characterize the fatigue loading. These moments reflect successively more detailed physical characteristics of the loading (mean, spread, tail behavior). Moments can be calculated from data samples and functional forms can be fitted to wind conditions, such as wind speed and turbulence intensity, with standard regression techniques. Distributions of load amplitudes that accurately reflect the damaging potential of the loadings can be estimated from the moments at any wind condition of interest. Fatigue life can then be calculated from the estimated load distributions, and the overall, long-term, or design spectrum can be generated for any particular wind-speed distribution. Characterizing the uncertainty in the distribution of cyclic loads is facilitated by using a small set of descriptive statistics for which uncertainties can be estimated. The effects of loading parameter uncertainty can then be transferred to the fatigue life estimate and compared with other uncertainties, such as material durability.
Exact superpotentials in N = 1 theories with flavor and their matrix model formulation

Abstract In this Letter we investigate the effective superpotential of an N =1 U ( N c ) gauge theory with one adjoint chiral multiplet and N f fundamental chiral multiplets. We propose a matrix model prescription in which only matrix model diagrams with less than two boundaries contribute to the gauge theory effective superpotential. This prescription reproduces exactly the known gauge theory physics for all N f and N c . For N f ⩽ N c −1 this is given by the Affleck–Dine–Seiberg superpotential. For N f ⩾ N c +1 we present arguments leading to the conclusion that the dynamics of these theories is also reproduced by the matrix model.
Toward understanding heterogeneity in computing

Heterogeneity complicates the efficient use of multicomputer platforms, but does it enhance their performance? their cost effectiveness? How can one measure the power of a heterogeneous assemblage of computers (“cluster,” for short), both in absolute terms (how powerful is this cluster) and relative terms (which cluster is more powerful)? What makes one cluster more powerful than another? Is one better off with a cluster that has one super-fast computer and the rest of “average” speed or with a cluster all of whose computers are “moderately” fast? If you could replace just one computer in your cluster with a faster one, which computer would you choose: the fastest? the slowest? How does one even ask questions such as these in a rigorous, yet tractable manner? A framework is proposed, and some answers are derived, a few rather surprising. Three highlights: (1) If one can replace only one computer in a cluster by a faster one, it is provably (almost) always most advantageous to replace the fastest one. (2) If the computers in two clusters have the same mean speed, then, empirically, the cluster with the larger variance in speed is (almost) always the faster one. (3) Heterogeneity can actually lend power to a cluster!
Model Atmospheres for RR Lyrae Stars

RR Lyrae gap stellar model atmospheres including radiation spectra, temperature radiation and convection, etc
Total Synthesis of ent-Dioxepandehydrothyrsiferol via a Bromonium-Initiated Epoxide-Opening Cascade

In the first total synthesis of ent-dioxepandehydrothyrsiferol, the signature trans-anti-trans 7,7,6-fused tricyclic polyether framework was constructed in a single bromonium-initiated epoxide-opening cascade that incorporates both endo- and exo-selective epoxide openings, each directed by the substitution pattern of the epoxide (methyl groups). This study thus demonstrates the feasibility of a possible biogenesis.
Prioritizing Practice in Ombudsman and ADR Programs

This article examines ways in which the Office of the Ombudsman/Center for Cooperative Resolution (OO/CCR) at the National Institutes of Health pursues activities that comprise an orientation toward practice and supports development of an “activist” ombudsman orientation. The article opens by describing challenges that alternative dispute resolution (ADR) organizations face, contrasts them with the experience of OO/CCR, details elements of a practice orientation as experienced at OO/CCR, and suggests ways in which ADR and ombudsman organizations may address their own challenges and pursue a practice orientation.
IMPROVEMENT IN SEVERE KIDNEY DYSFUNCTION AFTER IMPLANTATION OF CONTINUOUS-FLOW LEFT VENTRICULAR ASSIST DEVICES

Purpose Severe renal dysfunction is common among patients with advanced heart failure and is a contraindication for isolated heart transplantation. Left ventricular assist device (LVAD) may improve circulation and renal function in these patients. This study aimed to determine the effect of severe renal dysfunction on outcomes after LVAD implantation. Methods and Materials A retrospective analysis of 72 consecutive patients implanted with HeartMate II LVAD was conducted. Patients were divided into two groups based on GFR during pre- LVAD hemodynamic optimization: 1-GFR > 40 and 2- GFR ≤ 40 ml. Results In all patients, GFR increased at 1 and 3 months after LVAD implantation and declined at 6 month to the pre-operative value. In the GFR ≤ 40 group improvement in GFR over 6 months was statistically significant compared to pre-operative value.[table1]Post-LVAD survival at 1, 3, and 6 month was 94%, 85% and 65% for the GFR > 40 group, and 100%, 70% and 57% for the GFR ≤ 40 group (p=0.11). Notably, renal function worsened in 21 (29%) patients at 1 month after LVAD implantation. Severe right ventricle dysfunction before and early after LVAD independently predicted worsening in renal function; these patients also had significantly lower post-LVAD survival (p Conclusions Severe renal dysfunction improved after LVAD implantation. Worsening renal function at 1 month after LVAD is predicted by right ventricle dysfunction before and early after LVAD implantation and is associated with poorer survival. Changes in Kidney Function Overall GFR (n=72) GFR >40 (n=57) GFR ≤ 40 (n=15) Pre LVAD 60 +/− 26 68 +/− 26 35 +/− 3 1 month post LVAD (p) 73 +/−25 (0.001) 75 +/− 24 (0.06) 63 +/− 26 (0.002) 3 months post LVAD (p) 76 +/− 33 (0.001) 79 +/− 34 (0.04) 61 +/− 24 (0.009) 6 months post LVAD (p) 63 +/− 26 (0.058) 65 +/− 26 (0.5) 54 +/− 25 (0.02)
Neutralino-stop coannihilation in the CMSSM

Abstract Neutralino as the lightest supersymmetric particle (LSP) is a candidate for supersymmetric dark matter. It is known that coannihilation effects could be important in neutralino relic density calculation. Here we present some results on neutralino-stop coannihilation in the CMSSM. In this model, the stop t 1 can be degenerate with the lightest neutralino χ when |A0| ≠ 0 and large, more specifically when the lighter stop mass is suppressed by large off diagonal terms in the stop square mass matrix. In the region where t 1 is slightly heavier than χ, the coannihilation effect brings the relic density into the range favored by cosmology. While the χ − t 1 coannihilation channels do not increase the range of mχ, they do extend the cosmologically preferred region to larger values of m0.
A formal model of trade-off between optimization and execution costs in semantic query optimization

Abstract Conventional query optimizers assume that the cost of optimization is negligible. This assumption does not hold for much larger search spaces (of possible execution plans) such as those encountered during semantic query optimization. In particular, the optimization cost can become comparable to the execution cost, and thus a significant fraction of the response time for interactive queries [1]. This paper discusses the trade-off between the two costs in the context of semantic query optimization with regard to a set of integrity constraints, and reports a heuristic search algorithm which minimizes a weighted sum of both the costs. A detailed analysis of an experiment is presented to strengthen the claim. The optimization considered in this paper is with respect to a set of semantic integrity constraints.
The Institutional Framing of Policy Debates: Economics Versus the Environment

By framing the economics versus environment debate as a mixed-motive situation, opportunities become visible that allow greater benefits to all interests in the debate. Yet, social, cultural, and institutional arrangements frame how these interests see these opportunities, creating a barrier to mixed-motive analyses. In this article, the authors use an institutional perspective to analyze how the economics versue environment debate emerges from institutions as presently structured. They present an analysis of its present framing based on three aspects of institutions—regulative, normative, and cognitive—and consider the prescriptive implications they expose at the managerial and organizational level of action. The authors conclude with an analysis of possible solutions to overcome them.
Synthesis of a cyclic urea as a nonnatural biopolymer scaffold

A cyclic urea trimer was synthesized from readily available amino acid derivatives using a simple, iterative approach. A selective amide reduction using borane (BH3-THF) and a triphosgenemediated cyclization are the key features in a synthesis of the cyclic urea trimer 2.
Observation of Long Decoherence Times in a Quantum Logic Gate using Trapped Ba137 Ions

We have measured a coherence lifetime > 1 millisecond for the phonons in a Cirac-Zoller quantum logic gate using the Ba137 ion. The microtrap of 80 microns radius does not show an anomalously fast decay.
Study of external dynamic flap loads on a 6 percent B-1B model

The origin of dynamic pressure loads on external divergent engine nozzle flaps of the B-1B aircraft was investigated in the NASA/LaRC 16 foot transonic tunnel using a 6 percent full span model with powered engine nacelles. External flap dynamic loads and afterbody drag associated with flap removal were measured using this model. Both dry and max. A/B power nozzles were evaluated in this study. As a result of this study, the principal mechanisms responsible for high dynamic external flap loads were determined along with performance penalty associated with flap removal.
Plasma detachment from a magnetic nozzle

Magnetic nozzles are used to convert plasma pressure into directed flow, thereby providing thrust for propulsion. The detachment of the flow from the magnetic field must be highly directed or the thrust efficiency will be low. A simple model of flowing, cold plasma in an axisymmetric nozzle is considered to determine the fundamental physics and scaling of separation in the limiting case that it is determined by plasma inertia. Ion and electron motions are coupled by the ambipolar electric field. In the limit of negligible meridional electric current, separation from the field is determined by the hybrid (electron-ion) Larmor radius evaluated at the initial magnetic flux and flow velocity. It is shown that the detachment is thereby significantly constrained, but that significant improvement can be obtained if electric currents can flow across the magnetic field either in walls or as plasma currents, or if dissipative effects are sufficiently strong.
A Stability Investigation for an Incompressible Simple Fluid with Fading Memory

The nonlinear equations of motion for an incompressible simple fluid, occupying a fixed bounded container, are formulated on the basis of the “finitelinear” viscoelasticity theory for materials with fading memory; this formal boundary-initial value problem is then viewed as a nonlinear abstract evolution equation on a certain Hilbert space. It is shown that a linearized version of this evolution equation is associated with a linear dynamical system on this Hilbert space, and several results for stability and asymptotic behavior for this linearized problem are proved through the use of Liapunov stability methods. On the assumption that the original nonlinear evolution equation also is associated with some dynamical system on the same space, it is shown that the rest condition of the fluid is stable and all motions are bounded. The Liapunov function employed for this purpose can be interpreted as a mechanical energy function for the fluid.
Magnetic and structural properties of NaLnMnWO6 and NaLnMgWO6 perovskites

We have prepared 14 new AA'BB'O{sub 6} perovskites which possess a rock salt ordering of the B-site cations and a layered ordering of the A-site cations. The compositions obtained are NaLnMnWO{sub 6} (Ln=Ce, Pr, Sm, Gd, Dy, and Ho) and NaLnMgWO{sub 6} (Ln=Ce, Pr, Sm, Eu, Gd, Tb, Dy, and Ho). The samples were structurally characterized by powder X-ray diffraction which has revealed metrically tetragonal lattice parameters for compositions with Ln=Ce, Pr and monoclinic symmetry for compositions with smaller lanthanides. Magnetic susceptibility vs. temperature measurements have found that all six NaLnMnWO{sub 6} compounds undergo antiferromagnetic ordering at temperatures between 10 and 13 K. Several compounds show signs of a second magnetic phase transition. One sample, NaPrMnWO{sub 6}, appears to pass through at least three magnetic phase transitions within a narrow temperature range. All eight NaLnMgWO{sub 6} compounds remain paramagnetic down to 2 K revealing that the ordering of the Ln{sup 3+} cations in the NaLnMnWO{sub 6} compounds is induced by the ordering of the Mn{sup 2+} sub-lattice. - Graphical abstract: Evidence for multiple magnetic phase transitions in the A and B-site ordered perovskite NaPrMnWO{sub 6}.
The Earnings and Employment of Nurses in an Era of Cost Containment

Previous research has shown that from the 1980s through the early 1990s, nurses enjoyed substantial wage and employment gains that stemmed, to some extent, from increased labor demand. Using indivi...
Preparation and reactions of N-thioformyl peptides from amino thioacids and isonitriles

The preparation of N-thioformyl peptides from amino thioacids and isonitriles at room temperature is described.
Aspects of graviton detection: graviton emission and absorption by atomic hydrogen

Graviton absorption cross sections and emission rates for hydrogen are calculated by both semi-classical and field theoretic methods. We point out several mistakes in the literature concerning spontaneous emission of gravitons and related phenomena, some of which are due to a subtle issue concerning gauge invariance of the linearized interaction Hamiltonian.
Inclination Effects in Spiral Galaxy Gravitational Lensing

Spheroidal components of spiral galaxies have been considered to be the only dynamically important component in gravitational lensing studies to date. Here we point out that including the disk component can have a significant effect, which depends on the disk inclination, on a variety of lensing properties that are relevant to present studies and future surveys. As an example, we look at the multiple image system B1600+434, which was recently identified as being lensed by a spiral galaxy. We find that by including the disk component, one can understand the fairly large image separation as being caused by the inclination of a typical spiral rather than the presence of a very massive halo. The fairly low magnification ratio can also be readily understood if the disk is included. We also discuss how such lensed systems might allow one to constrain parameters of spiral galaxies such as a disk-to-halo mass ratio and disk mass scale length. Another example we consider is the quasar multiple-lensing cross section, which we find can increase many-fold at high inclination for a typical spiral. Finally, we discuss the changes in the gravitational lensing effects on damped Lyα systems when disk lensing is included.
$$k$$-Double Schur functions and equivariant (co)homology of the affine Grassmannian

The Schubert bases of the torus-equivariant homology and cohomology rings of the affine Grassmannian of \(SL_{k+1}\) are realized by new families of symmetric functions called \(k\)-double Schur functions and affine double Schur functions.
WIYN OPEN CLUSTER STUDY. XXIV. STELLAR RADIAL-VELOCITY MEASUREMENTS IN NGC 6819

We present the current results from our ongoing radial-velocity (RV) survey of the intermediate-age (2.4 Gyr) open cluster NGC 6819. Using both newly observed and other available photometry and astrometry, we define a primary target sample of 1454 stars that includes main-sequence, subgiant, giant, and blue straggler stars, spanning a magnitude range of 11 ?V? 16.5 and an approximate mass range of 1.1-1.6 M ?. Our sample covers a 23 arcminute (13 pc) square field of view centered on the cluster. We have measured 6571 radial velocities for an unbiased sample of 1207 stars in the direction of the open cluster NGC 6819, with a single-measurement precision of 0.4 km s?1 for most narrow-lined stars. We use our RV data to calculate membership probabilities for stars with ?3 measurements, providing the first comprehensive membership study of the cluster core that includes stars from the giant branch through the upper main sequence. We identify 480 cluster members. Additionally, we identify velocity-variable systems, all of which are likely hard binaries that dynamically power the cluster. Using our single cluster members, we find a cluster average RV of 2.34 ? 0.05 km s?1. We use our kinematic cluster members to construct a cleaned color-magnitude diagram from which we identify rich giant, subgiant, and blue straggler populations and a well defined red clump. The cluster displays a morphology near the cluster turnoff clearly indicative of core convective overshoot. Finally, we discuss a few stars of note, one of which is a short-period red-clump binary that we suggest may be the product of a dynamical encounter.
Synthesis of marine sponge bisindole alkaloids dihydrohamacanthins.

A convergent synthesis of the marine sponge bisindole alkaloids dihydrohamacanthins is described. The synthesis centers on the construction of 3,5- and 3,6-linked pyrazinones and their reduction to the requisite piperazinones with sodium cyanoborohydride.
Oxidative reactions of cellulose initiated by free radicals

Oxidative reactions in cellulose are commonly initiated by thermal, ultraviolet, and high-energy radiations and by chemical oxidation. Long-lived free radicals, formed in cellulose on the localization of energy from thermal, ultraviolet, and high-energy radiations, and short-lived free radicals, formed in cellulose by oxidation, e.g., by ceric ion or redox reactions, were investigated by electron spin resonance spectroscopy. Dehydrogenation and oxidative depolymerization reactions of cellulose are indicated. The physical, chemical, and morphological effects of these free-radical initiated reactions on cellulose are summarized. The formation of free radicals in cellulose also increases the chemical reactivity of cellulose, particularly for chain copolymerization reactions with vinyl monomers. Preparation of cellulose-poly(vinyl) copolymers, using free-radical initiation, yields paper, film, wood, and textile products with new physical and chemical properties.
Some aspects of the source description of gravitation

Abstract We contribute to the source description of gravitation due to Schwinger by developing the necessary gravitational modifications of the couplings of various Boson fields to their sources and by providing a numerical supplement to his qualitative discussion of two-particle exchange.
Electrical contacts to carbon nanotubes down to 1nm in diameter

Rhodium (Rh) is found similar to Palladium (Pd) in making near-Ohmic electrical contacts to single-walled carbon nanotubes (SWNTs) with diameters d>∼1.6nm. Non-negligible positive Schottky barriers (SBs) exist between Rh or Pd and semiconducting SWNTs (S-SWNTs) with d<∼1.6nm. With Rh and Pd contacts, the characteristics of SWNT field-effect transistors and SB heights at the contacts are largely predictable based on the SWNT diameters, without random variations among devices. Surprisingly, electrical contacts to metallic SWNTs (M-SWNTs) also appear to be diameter dependent especially for small SWNTs. Ohmic contacts are difficult for M-SWNTs with diameters ⩽∼1.0nm possibly due to tunnel barriers resulted from large perturbation of contacting metal to very small diameter SWNTs due to high chemical reactivity of the latter.
Probe Brane Dynamics and the Cosmological Constant

Abstract Recently a brane world perspective on the cosmological constant and the hierarchy problems was presented. Here, we elaborate on some aspects of that particular scenario and discuss the stability of the stationary brane solution and the dynamics of a probe brane. Even though the brane is unstable under a small perturbation from its stationary position, such instability is harmless when the 4-D cosmological constant is very small, as is the case of our universe. One may also introduce radion stabilizing potentials in a more realistic scenario.
Efficient image database retrieval using wavelet packets and principal component analysis

With the advancement of multimedia technology and the internet, numerous applications have arisen which require the storage and retrieval of large image and video databases. A novel method (Eigenwavelet) was developed to retrieve images from a large heterogeneous image database upon a user-specified query. The queries are in the form of an image(s) that the user seeks to find similar matches to in the database. Using the queries, an efficient algorithm was developed which decomposed each image in the database using wavelet packet analysis. Along each node of the packet tree, Principal Component Analysis was applied to the database images after wavelet packet decomposition, and a set of eigenvectors were generated for each node of the packet tree. To search the image database, the query images are projected onto these eigenvectors (Eigenwavelet coefficients). A distance metric is computed between the projections of the queries and the projections of the images in the database onto the eigenwavelets. Those images with minimal distance (L1) are retrieved in response to a unique query set. Simulations with a heterogeneous image database suggest the Eigenwavelet method of image retrieval is a robust and computationally tractable method of retrieving images with a probability of detection >.8.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.