cssi/SciSciGPT-SciSciNet huggingface dataset:
Frugal and Truthful Auctions for Vertex Covers, Flows and Cuts

We study truthful mechanisms for hiring a team of agents in three classes of set systems: Vertex Cover auctions, k-???ow auctions, and cut auctions. For Vertex Cover auctions, the vertices are owned by selfish and rational agents, and the auctioneer wants to purchase a vertex cover from them. For k-???ow auctions, the edges are owned by the agents, and the auctioneer wants to purchase k edge-disjoint s-t paths, for given s and t. In the same setting, for cut auctions, the auctioneer wants to purchase an s-t cut. Only the agents know their costs, and the auctioneer needs to select a feasible set and payments based on bids made by the agents. We present constant-competitive truthful mechanisms for all three set systems. That is, the maximum overpayment of the mechanism is within a constant factor of the maximum overpayment of any truthful mechanism, for every set system in the class. The mechanism for Vertex Cover is based on scaling each bid by a multiplier derived from the dominant eigenvector of a certain matrix. The mechanism for k-???ows prunes the graph to be minimally (k + 1)-connected, and then applies the Vertex Cover mechanism. Similarly, the mechanism for cuts contracts the graph until all s-t paths have length exactly 2, and then applies the Vertex Cover mechanism.
Doppler Signatures of the Atmospheric Circulation on Hot Jupiters

The meteorology of hot Jupiters has been characterized primarily with thermal measurements, but recent observations suggest the possibility of directly detecting the winds by observing the Doppler shift of spectral lines seen during transit. Motivated by these observations, we show how Doppler measurements can place powerful constraints on the meteorology. We show that the atmospheric circulation?and Doppler signature?of hot Jupiters splits into two regimes. Under weak stellar insolation, the day-night thermal forcing generates fast zonal jet streams from the interaction of atmospheric waves with the mean flow. In this regime, air along the terminator (as seen during transit) flows toward Earth in some regions and away from Earth in others, leading to a Doppler signature exhibiting superposed blueshifted and redshifted components. Under intense stellar insolation, however, the strong thermal forcing damps these planetary-scale waves, inhibiting their ability to generate jets. Strong frictional drag likewise damps these waves and inhibits jet formation. As a result, this second regime exhibits a circulation dominated by high-altitude, day-to-night airflow, leading to a predominantly blueshifted Doppler signature during transit. We present state-of-the-art circulation models including non-gray radiative transfer to quantify this regime shift and the resulting Doppler signatures; these models suggest that cool planets like GJ?436b lie in the first regime, HD?189733b is transitional, while planets hotter than HD?209458b lie in the second regime. Moreover, we show how the amplitude of the Doppler shifts constrains the strength of frictional drag in the upper atmospheres of hot Jupiters. If due to winds, the ~2 km s?1 blueshift inferred on HD?209458b may require drag time constants as short as 104-106?s, possibly the result of Lorentz-force braking on this planet's hot dayside.
A Battery Management System Using an Active Charge Equalization Technique Based on a DC/DC Converter Topology

An active charge equalization technique based on a dc/dc converter topology is proposed in this paper. The technique achieves cell balancing of batteries in a stack in terms of both voltage and charge as the pack is being charged/discharged and in idle periods to maximize the energy and reliability of stack operation. A set of MOSFET switches controlled by a voltage monitoring circuit ensures that each battery module has the same output voltage by transferring charge from an individual battery module with the highest voltage to a weak module. An overvoltage and overdischarge protection circuit is presented to reduce the degradation of battery life and to operate each battery within the voltage limits.
Equity in out-of-pocket payments for hospital care: Evidence from India

Abstract Background The lack of formal health insurance and inadequate social safety nets cause families in most low-income countries to finance health spending through out-of-pocket (OOP) payments, leaving poor families unable to insure their consumption during periods of major illnesses. Objective To examine how well the Indian healthcare system protects households of differing living standards against the financial consequences of unanticipated health shocks. Data The data are drawn from the 52nd round of National Sample Survey, a nationally representative socioeconomic and health survey conducted in 1995–1996. The sample comprises 24,379 (3.84%) households where a member was hospitalized during the 1-year reference period. Methods We estimate, using ordinary least squares, the relationship between household consumption (proxy for ability to pay) and OOP payments for hospitalization. We also estimate the relationship between consumption and OOP share in consumption. Results Our results indicate that both utilization (payments) and the consequent financial burden (payment share) increases with increasing ability to pay (ATP). While this relationship is retained across the different subgroups (e.g., gender, social code, region, etc.), comparisons across groups indicate horizontal inequities including differences in both degrees of progressivity and the redistributive effect. Conclusion The finding that OOP payments do not decline with ATP could be an indication of: (1) the lack of insurance which implies that the better-off must pay from OOP to secure quality health care and (2) the absence of risk-pooling or prepayments mechanisms which poses financial impediments to the consumption of health care by the poor.
Designing warning signs and warning labels: Part II — Scientific basis for initial guidelines

This chapter discusses the design of warnings into useful guidelines for the sophisticated practitioner. These guidelines should (1) address all aspects of human behavior, including perception, comprehension, and decision-making and (2) must be operationally useful for determining when warnings should be provided. The chapter discusses existing safety signage and labeling systems along with models of the warning process and their important role in identifying and resolving warning sign and label-related design issues. Safety signage and labeling systems provide an operational set of guidelines for developing a warning sign or label. A commonly cited advantage of conforming to these systems is that they convey hazards in a rather stereotypical and explicit way. They also provide a means for practitioners who are not necessarily experts in warning sign or label design to develop warnings that meet basic perceptual requirements. The guidelines presented in the chapter are developed on the basis of such an approach and provide a starting point for combining the positive elements of traditional approaches for designing warnings with a more cognitively oriented perspective.
JR: Flexible distributed programming in an extended Java

Java provides a clean object-oriented programming model and allows for inherently system-independent programs. Unfortunately, Java has a limited concurrency model, providing only threads and remote method invocation (RMI).The JR programming language extends Java to provide a rich concurrency model, based on that of SR. JR provides dynamic remote virtual machine creation, dynamic remote object creation, remote method invocation, asynchronous communication, rendezvous, and dynamic process creation. JR's concurrency model stems from the addition of operations (a generalization of procedures) and JR supports the redefinition of operations through inheritance. JR programs are written in an extended Java and then translated into standard Java programs. The JR run-time support system is also written in standard Java.This paper describes the JR programming language and its implementation. Some initial measurements of the performance of the implementation are also included.
A Model for Large-Amplitude Internal Solitary Waves with Trapped Cores

Abstract. Large-amplitude internal solitary waves in continuously stratified systems can be found by solution of the Dubreil-Jacotin-Long (DJL) equation. For finite ambient density gradients at the surface (bottom) for waves of depression (elevation) these solutions may develop recirculating cores for wave speeds above a critical value. As typically modeled, these recirculating cores contain densities outside the ambient range, may be statically unstable, and thus are physically questionable. To address these issues the problem for trapped-core solitary waves is reformulated. A finite core of homogeneous density and velocity, but unknown shape, is assumed. The core density is arbitrary, but generally set equal to the ambient density on the streamline bounding the core. The flow outside the core satisfies the DJL equation. The flow in the core is given by a vorticity-streamfunction relation that may be arbitrarily specified. For simplicity, the simplest choice of a stagnant, zero vorticity core in the frame of the wave is assumed. A pressure matching condition is imposed along the core boundary. Simultaneous numerical solution of the DJL equation and the core condition gives the exterior flow and the core shape. Numerical solutions of time-dependent non-hydrostatic equations initiated with the new stagnant-core DJL solutions show that for the ambient stratification considered, the waves are stable up to a critical amplitude above which shear instability destroys the initial wave. Steadily propagating trapped-core waves formed by lock-release initial conditions also agree well with the theoretical wave properties despite the presence of a "leaky" core region that contains vorticity of opposite sign from the ambient flow.
Sensitivity analysis for probability assessments in Bayesian networks

When eliciting a probability model from experts, knowledge engineers may compare the results of the model with expert judgment on test scenarios, then adjust model parameters to bring the behavior of the model more in line with the experts intuition. This paper presents a methodology for analytic computation of sensitivity values in Bayesian network models. Sensitivity values are partial derivatives of output probabilities with respect to parameters being varied in the sensitivity analysis. They measure the impact of small changes in a network parameter on a target probability value or distribution. Sensitivity values can be used to focus knowledge elicitation effort on those parameters having the most impact on outputs of concern. Analytic sensitivity values are computed for an example and compared to sensitivity analysis by direct variation of parameters. >
On the performance of combined data flow and control flow systems: experiments using two iterative algorithms

Improved multiprocessor performance can be attained by combining data flow and control flow concepts. This type of combined architecture is characterized and several examples of previously proposed machines are given. A new model that permits the analysis of such systems is presented and performance measures are defined. This model is then used to analyze the performance of the algorithms under a wide variety of combined systems. The results of these experiments show that partition size is a major factor in the performance of such systems and an optimal size may be found for given system parameters.
Experimental studies of the turbulent wake behind self-propelled slender bodies

The turbulent wakes behind a drag body, a jet-propelled body, and a propeller-driven body all with the same streamlined forebody shape were studied experimentally in a subsonic wind tunnel at a nominal Reynolds number based on diameter of 6 x 10. The wakes produced by the latter two bodies were momentumless. Mean flow and turbulence data were taken at five axial stations (X/D = 2, 5, 10, 20, and 40) downstream of the sterns of these bodies. The data for the wake behind the drag body compare favorably with previous experiments and establish a rigid reference for the wakes behind the self-propelled configurations. The downstream rate of decay of the velocity defect is essentially the same for the drag and propeller-driven bodies, whereas the decay for the jet-propelled body is substantially faster. The magnitude of the axial turbulence intensity is greater for the jetpropelled model than the other models, and the absolute value of the radial shear stress is greater (beyond X/D= 2) for the propeller-driven model. The rate of decay of the axial turbulence intensity is faster for the propellerdriven model than the jet-propelled model, however the rate of decrease of radial shear stress is faster for the jet propelled model.
Molecular Imaging of Amyloidosis: Will the Heart Be the Next Target After the Brain?

Amyloidosis is a heterogeneous group of diseases with a common feature of extracellular deposition and infiltration of different types of amyloid fibrils in various organs. For example, Alzheimer’s disease is characterized by deposition of amyloid β in the brain. Radiolabeled positron emission tomography (PET) tracers, mainly derivatives of thioflavin-T, were recently introduced for identification of amyloid β plaques in Alzheimer’s patients. Such advances of amyloid β plaque imaging of the brain may shed light into imaging of other organs in amyloidosis patients, such as the heart. Cardiac infiltration of amyloid confers poor clinical outcomes, which renders early diagnosis for appropriate clinical management. At present, nuclear imaging of cardiac amyloidosis is predominantly accomplished with bone-seeking radiotracers, such as 99m-technetium-labeled pyrophosphate (99mTc-PYP), 99m-technetium-methylene diphosphonate (99mTc-MDP), and 99m-technetium-3,3,-diphosphono-1,2-propanodicarboxylic acid (99mTc-DPD), with conflicting results in terms of diagnostic performance, with the exception for 99mTc-DPD, which may differentiate light-chain amyloidosis from transthyretin-related cardiac amyloidosis. Although other non–bone-seeking radiotracers such as iodine-123-labeled amyloid P component (123I-SAP), 123-iodine-Meta-iodobenzylguanidine (123I-mIBG), 99m-technetium-labeled protease inhibitor, and indium-111-labeled amyloid antibodies have also shown some success in identifying cardiac amyloidosis, the future, however, may lie in labeling derivatives of thioflavin-T. With the recent success of visualizing deposition of amyloid β in the brain, the US Food and Drug Administration–approved PET imaging agent 18F-florbetapir may be used to target cardiac amyloidosis next.
The middle time.

The people on the road just do not understand the general need to get out of my way. Frustration and resentment are not too far under my skin after 30-odd hours of wakefulness and decision making. ...
Mineral aerosol and cloud interactions

[1] Interactions between aerosols and clouds are the subject of considerable scientific research, due to the importance of clouds in controlling climate. Here we consider the relationship between mineral aerosols and cloud properties over North Africa and the North Atlantic using monthly mean observations of mineral aerosols and clouds over 16 years. The results of this study are consistent with mineral aerosols suppressing precipitation in thin low altitude clouds and changing cloud amounts in ice phase clouds. Because we cannot eliminate either spurious correlations, or that the cloud and dust changes are both driven by the same meteorological conditions, we cannot provide definitive conclusions. However, these results suggest complicated and tantalizing feedbacks between mineral aerosols and climate. This question becomes crucial as we note that mineral aerosols from North Africa have increased substantially since the 1960s for reasons which are poorly understood but that may be linked to human activity.
Gamma-Ray Spectral States of Galactic Black Hole Candidates

OSSE has observed seven transient black hole candidates: GRO J0422+32, GX 339-4, GRS 1716-249, GRS 1009-45, 4U 1543-47, GRO J1655-40, and GRS 1915+105. Two gamma-ray spectral states are evident, and based on a limited number of contemporaneous X-ray and gamma-ray observations, these states appear to be correlated with X-ray states. The former three objects show hard spectra below 100 keV (photon number indices Γ < 2) that are exponentially cut off with folding energy ~100 keV, a spectral form that is consistent with thermal Comptonization. This breaking gamma-ray state is the high-energy extension of the X-ray low, hard state. In this state, the majority of the luminosity is above the X-ray band, carried by photons of energy ~100 keV. The latter four objects exhibit a power-law gamma-ray state, with a relatively soft spectral index (Γ ~ 2.5-3) and no evidence for a spectral break. For GRO J1655-40, the lower limit on the break energy is 690 keV. GRS 1716-249 exhibits both spectral states, with the power-law state having significantly lower gamma-ray luminosity. The power-law gamma-ray state is associated with the presence of a strong ultrasoft X-ray excess (kT ~ 1 keV), the signature of the X-ray high, soft (or perhaps very high) state. The physical process responsible for the unbroken power law is not well understood, although the spectra are consistent with bulk-motion Comptonization in the convergent accretion flow.
An ALE method for compressible multi-material flows on unstructured grids

Multi-material flows, where a moving interface exists between two immiscible fluids, can be found in a variety of engineering problems. Development of numerically accurate and computationally efficient algorithms for multi-material flow simulations remains one of the unresolved issues in computational fluid dynamics. These flow problems are characterized by the existence of material interfaces. The modeling of these complicated free boundaries poses a difficult numerical challenge, as they are either time dependent or unknown a priori and determined as part of the solution. A number of numerical methods exist for solving the interface problems: interface capturing methods (mixed cell methods), level set methods, volume of fluid and interface reconstruction methods, interface tracking methods, free-Lagrange methods. Unfortunately, there are still limitations and shortcomings attached to each of them. In general, for all these methods that allow mixed cells, the computation of thermodynamical variables such as pressure, speed of sound, and temperature on mixed cells is difficult to achieve correctly. In particular, when the equations of state for different materials are drastically different, a small error on the thermodynamical variables can lead to collapse or meaningless of the computation. For all these methods where the interface is represented and tracked explicitly either by marking it with special marker points, or by treating it like a boundary, it is difficulty to handle very complex free surface problems, especially those involving interface topological changes such as merging or breakup of the interface.
Commercial Property Rent Dynamics in U.S. Metropolitan Areas: An Examination of Office, Industrial, Flex and Retail Space

This paper is concerned with the market rental rate for space offered by commercial property and how that rental rate evolves over time. Rental rates reflect the value of the services provided by the property and can have a significant impact on the ability of its owners to make monthly debt obligations. We investigate commercial property rent dynamics for 34 large metropolitan areas in the U.S. The dynamics are studied from the second quarter of 1990 through the second quarter of 2009 and the results are compared across four property types or uses (office, industrial, flex, and retail). There is substantial heterogeneity in both the long and short run responses to changing demand and supply conditions. In general, the office market is the slowest to adjust back towards equilibrium while industrial and flex markets adjust back to the long run equilibrium very quickly. For industrial and office types, the speed of adjustment is substantially faster within quality segments and is strongest for grade A properties.
NMR Quantum Information Processing

Nuclear magnetic resonance (NMR) has provided a valuable experimental testbed for quantum information processing (QIP). Here, we briefly review the use of nuclear spins as qubits, and discuss the current status of NMR-QIP. Advances in the techniques available for control are described along with the various implementations of quantum algorithms and quantum simulations that have been performed using NMR. The recent application of NMR control techniques to other quantum computing systems are reviewed before concluding with a description of the efforts currently underway to transition to solid state NMR systems that hold promise for scalable architectures.
Hazardous waste sites and housing appreciation rates

Abstract Housing appreciation rates reflect the speed of the market's adjustment to equilibrium. The dynamic effect of a hazardous waste site is analyzed by investigating the causal relationship between housing appreciation rates and house location in relation to a hazardous waste site using resale data from individual sales transactions in Dallas County, Texas. The results indicate that residential property owners in close proximity to the hazardous waste site experienced lower housing appreciation rates after the time period when the US Environmental Protection Agency identified the site. The adjustment to equilibrium, as reflected in differential housing appreciation rates, can be quite lengthy in response to the identification and cleanup process for a hazardous waste site. The results suggest that cleanup actions are not as important as new information that the area surrounding the site is a dangerous place.
Route selection in backbone data communication networks

Abstract This paper addresses the problem of selecting a route for every pair of communicating nodes in a backbone network in order to minimize the mean delay faced by messages. The problem was previously modeled as a network of M/M/1 queues. We present a modified mathematical programming formulation of the problem. This modification facilitates a new Lagrangian relaxation of this nonlinear optimization problem. A solution procedure utilizing this relaxation is developed. Extensive computational results across a variety of networks are reported. These results indicate that the solution procedure is effective for a wide range of traffic loads.
Documentation of Intraretinal Retinal Pigment Epithelium Migration via High-Speed Ultrahigh-Resolution Optical Coherence Tomography

Purpose To describe the features of intraretinal retinal pigment epithelium (RPE) migration documented on a prototype spectral-domain, high-speed, ultrahigh-resolution optical coherence tomography (OCT) device in a group of patients with early to intermediate dry age-related macular degeneration (AMD) and to correlate intraretinal RPE migration on OCT to RPE pigment clumping on fundus photographs. Design Retrospective, noncomparative, noninterventional case series. Participants Fifty-five eyes of 44 patients seen at the New England Eye Center between December 2007 and June 2008 with early to intermediate dry AMD. Methods Three-dimensional OCT scan sets from all patients were analyzed for the presence of intraretinal RPE migration, defined as small discreet hyperreflective and highly backscattering lesions within the neurosensory retina. Fundus photographs also were analyzed to determine the presence of RPE pigment clumping, defined as black, often spiculated, areas of pigment clumping within the macula. The en face OCT images were correlated with fundus photographs to demonstrate correspondence of intraretinal RPE migration on OCT and RPE clumping on fundus photography. Main Outcome Measures Drusen, dry AMD, intraretinal RPE migration, and RPE pigment clumping. Results On OCT scans, 54.5% of eyes (61.4% of patients) demonstrated intraretinal RPE migration. Of the fundus photographs, 56.4% demonstrated RPE pigment clumping. All eyes with intraretinal RPE migration on OCT had corresponding RPE pigment clumping on fundus photographs. The RPE pigment migrated most frequently into the outer nuclear layer (66.7% of eyes) and less frequently into more anterior retinal layers. Intraretinal RPE migration mainly occurred above areas of drusen (73.3% of eyes). Conclusions The appearance of intraretinal RPE migration on OCT is a common occurrence in early to intermediate dry AMD, occurring in 54.5% of eyes, or 61.4% of patients. The area of intraretinal RPE migration on OCT always correlated to areas of pigment clumping on fundus photography. Conversely, all but 1 eye with RPE pigment clumping on fundus photography also had areas of intraretinal RPE migration on OCT. The high incidence of intraretinal RPE migration observed above areas of drusen suggests that drusen may play physical and catalytic roles in facilitating intraretinal RPE migration in dry AMD patients. Financial Disclosure(s) Proprietary or commercial disclosure may be found after the references.
Buoyancy-Driven Flow Transitions in Deep Cavities Heated From Below

A numerical investigation has been conducted of flow transitions in deep three-dimensional cavities heated from below. The first critical Rayleigh number, Ra 1 , below which the flow is at rest, and the second critical Rayleigh number, Ra 11 , for transition from steady state to oscillatory flow, have been found for cavities of aspect ratios Ar in the range 1-5. Transition to chaos has also been examined for these cases
Electrochemical atomic layer epitaxy (ECALE)

Abstract Electrodeposition holds promise as a low cost, flexible room temperature technique for the production of II-VI compound semiconductors. Previous studies, however, have resulted in the production of polycrystalline deposits in every case. This paper describes a new method, developed in this laboratory, for depositing these materials epitaxially. The method involves the alternate deposition of the component elements a monolayer at a time. To limit deposition to a monolayer, underpotential deposition (UPD) is employed. UPD occurs because of the enhanced stability provided by bond formation between the II and VI elements, relative to formation of bulk elemental deposits. This method is the electrochemical equivalent of atomic layer epitaxy (ALE), and is thus referred to as “electrochemical atomic layer epitaxy” (ECALE). This paper describes the first example of the ECALE method, involving the thin-layer electrodeposition of CdTe on a Au polycrystalline electrode.
High-Dimensional Density Estimation via SCA: An Example in the Modelling of Hurricane Tracks ✩

We present nonparametric techniques for constructing and verifying density estimates from high-dimensional data whose irregular dependence structure cannot be modelled by parametric multivariate distributions. A low-dimensional representation of the data is critical in such situations because of the curse of dimensionality. Our proposed methodology consists of three main parts: (1) data reparameterization via dimensionality reduction, wherein the data are mapped into a space where standard techniques can be used for density estimation and simulation; (2) inverse mapping, in which simulated points are mapped back to the high-dimensional input space; and (3) verification, in which the quality of the estimate is assessed by comparing simulated samples with the observed data. These approaches are illustrated via an exploration of the spatial variability of tropical cyclones in the North Atlantic; each datum in this case is an entire hurricane trajectory. We conclude the paper with a discussion of extending the methods to model the relationship between TC variability and climatic variables.
The Cascades Proposal for the Deep Underground Science and Engineering Laboratory

One of the options for creating a Deep Underground Science and Engineering Laboratory (DUSEL) is a site in the Mt. Stuart batholith, a granodiorite and tonalite rock mass in the Cascade mountain range in Washington State. The batholithʼs 100-year history in hard-rock tunneling includes the construction of the longest and deepest tunnels in the U.S., the parallel Cascade and Pioneer tunnels. The laboratory plan would utilize these two tunnels to produce a laboratory that has many desirable features, including dedicated, clean, horizontal access, container-module transport, and low operations costs. Various aspects of the site help to reduce geotechnical, environmental, and safety risks.
Zimmermann type cancellation in the free Faà di Bruno algebra

Haiman and Schmitt showed that one can use the antipode SF of the colored Faa di Bruno Hopf algebra F to compute the (compositional) inverse of a multivariable formal power series. It is shown that the antipode SH of an algebraically free analogue H of F may be used to invert non-commutative power series. Whereas F is the incidence Hopf algebra of the colored partitions of finite colored sets, H is the incidence Hopf algebra of the colored interval partitions of finite totally ordered colored sets. Haiman and Schmitt showed that the monomials in the geometric series for SF are labeled by trees. By contrast, the non-commuting monomials of SH are labeled by colored planar trees. The order of the factors in each summand is determined by the breadth first ordering on the vertices of the planar tree. Finally there is a parallel to Haiman and Schmitt's reduced tree formula for the antipode, in which one uses reduced planar trees and the depth first ordering on the vertices. The reduced planar tree formula is proved by recursion, and again by an unusual cancellation technique. The one variable case of H has also been considered by Brouder, Frabetti, and Krattenthaler, who point out its relation to Foissy's free analogue of the Connes–Kreimer Hopf algebra.
Breaking up chains: the nitridocuprates(I) Ba[CuN] Ba16[(CuN)8][Cu2N3][Cu3N4] and Ca4Ba[CuN2]2

Abstract The three title compounds were prepared from copper or copper(I) oxide and alkaline earth metals in sodium fluxes under medium nitrogen pressures and structurally characterized. Ba[CuN] crystallizes monoclinic in C 2/c (No. 15), with Z =12, a =14.462(2) A, b =5.5700(8) A, c =9.478(1) A, β =102.960(2)°. The structure contains infinite chains ∞ 1 [CuN 2/2 2− ], which are kinked alternately at the first and then the second nitrogen atom. Ba 16 [(CuN) 8 ][Cu 2 N 3 ][Cu 3 N 4 ] crystallizes monoclinic in P2 1 /c (No. 14), with Z =1, a =9.5611(4) A, b =7.2731(2) A, c =13.5225(5) A, β =93.115(2)°. It is build from infinite helical chains ∞ 1 [CuN 2/2 2− ] separated by discrete linear [Cu 2 N 3 ] 7− and Z-shaped [Cu 3 N 4 ] 9− ions. Ca 4 Ba[CuN 2 ] 2 crystallizes tetragonal in P 4/ncc (No. 130), with Z =4, a =8.2366(4) A, c =12.5731(6) A. In this compound the nitridocuprate ions are broken down to isolated linear units [CuN 2 ] 5− .
Integrable sigma models and perturbed coset models

Sigma models arise frequently in particle physics and condensed-matter physics as low-energy effective theories. In this paper I compute the exact free energy at any temperature in two hierarchies of integrable sigma models in two dimensions. These theories, the SU(N)/SO(N) models and the O(2P)/O(P) × O(P) models, are asymptotically free and exhibit charge fractionalization. When the instanton coupling θ = π, they flow to the SU(N)1 and O(2P)1 conformal field theories, respectively. I also generalize the free energy computation to massive and massless perturbations of the coset conformal field theories SU(N)k/SO(N)2k and O(2P)k/O(P)k × O(P)k.
Implementing efficient graphs in connection networks

We consider the problem of sharing the cost of a network that meets the connection demands of a set of agents. The agents simultaneously choose paths in the network connecting their demand nodes. A mechanism splits the total cost of the network formed among the participants. We introduce two new properties of implementation. The first property, Pareto Nash implementation (PNI), requires that the efficient outcome always be implemented in a Nash equilibrium and that the efficient outcome Pareto dominates any other Nash equilibrium. The average cost mechanism and other asymmetric variations are the only mechanisms that meet PNI. These mechanisms are also characterized under strong Nash implementation. The second property, weakly Pareto Nash implementation (WPNI), requires that the least inefficient equilibrium Pareto dominates any other equilibrium. The egalitarian mechanism (EG) and other asymmetric variations are the only mechanisms that meet WPNI and individual rationality. EG minimizes the price of stability across all individually rational mechanisms.
Phenomenology of the minimal supergravity SU (5) model

The minimal grand unified supergravity model is discussed. Requiring radiative breaking of the electroweak gauge symmetry, the unification ofb and τ Yukawa couplings, a sufficiently stable nucleon, and not too large a relic density of neutralinos produced in the Big Bang constrains the parameter space significantly. In particular, the soft breaking parameterm 1/2 has to be less than about 130 GeV, and the top quark Yukawa coupling has to be near its (quasi) fixed point. The former condition implies $$m_{\bar g} \leqslant 400$$ GeV and hence very large production rates for gluino pairs at the LHC, while the latter constraint implies that the lighter stop and sbottom eigenstates are significantly lighter than the other squarks, leading to characteristic signatures for gluino pair events.
Thermodynamic and conductivity studies of nonstoichiometric cerium dioxide by coulometric titration: A simultaneous measurement

Abstract Simultaneous measurements of thermodynamic properties (ΔHo2 and ΔSo2) and electrical conductivity (σ) for constant compositions in nonstoichiometric cerium dioxide (CeO2−x) were carried out by coulometric titration in the temperature range 800–945°C and oxygen-partial-pressure range 10−10 to 10−21 atm. The thermodynamic quantities, ΔHo2 and ΔSo2 were calculated in the regime 1.86 × 10−3 ⩽ x ⩽ 3.16 × 10−2. In previous studies of metal oxides (e.g., CeO2−x), the electron mobility (μ) has been determined by combining separate experimental measurement of x and σ. In this study, the electrochemical, constant-composition technique is used as a fast and direct method for obtaining thermodynamic data and simultaneous measurements of the electrical conductivity.
Hypercontractivity for Semigroups of Unital Qubit Channels

Hypercontractivity is proved for products of qubit channels that belong to self-adjoint semigroups. The hypercontractive bound gives necessary and sufficient conditions for a product of the form $${e^{-t_1 H_1}\otimes \cdots \otimes e^{- t_n H_n}}$$ to be a contraction from L p to L q , where L p is the algebra of 2 n -dimensional matrices equipped with the normalized Schatten norm, and each generator H j is a self-adjoint positive semidefinite operator on the algebra of 2-dimensional matrices. As a particular case the result establishes the hypercontractive bound for a product of qubit depolarizing channels.
Equilibrium Growth in a Small Economy Facing an Imperfect World Capital Market

A growth model of a developing economy facing an upward-sloping curve of debt is analyzed. Equilibrium is characterized by transitional dynamics in which consumption, capital, and debt converge to a common growth rate. The adjustment is through the debt-capital ratio, which drives the borrowing rate to a level at which growth rates are equalized. The economy is subject to two externalities: a production externality associated with government expenditure, and a financial externality associated with the upward-sloping supply of debt. The tax structure that enables the decentalized economy to attain the first-best equilibrium is characterized.
On Centralizer Algebras for Spin Representations

We give a presentation of the centralizer algebras for tensor products of spinor representations of quantum groups via generators and relations. In the even-dimensional case, this can be described in terms of non-standard q-deformations of orthogonal Lie algebras; in the odd-dimensional case only a certain subalgebra will appear. In the classical case q = 1 the relations boil down to Lie algebra relations.
End-Wall and Profile Losses in a Low-Speed Axial Flow Compressor Rotor

The blade-to-blade variation of relative stagnation pressure losses in the tip region inside the rotor of a single-stage, axial-flow compressor, is presented and interpreted in this paper. The losses are measured at two flow coefficients (one at the design point and the other at the near peak pressure rise point) to discern the effect of blade loading on the end-wall losses. The tip clearance losses are found to increase with an increase in the pressure rise coefficient. The losses away from the tip region and near the hub regions are measured downstream. The losses are integrated and interpreted in this paper.
Macro Scale Independently Homogenized Subcells for Modeling Braided Composites

A method is needed which has the capability to analyze the impact response of carbon fiber composites, specifically those with a triaxially braid architecture. An analytical tool can be used to meet this need. This more accurate and versatile numerical simulation tool will help to better analyze the effect of dominant composites properties on impact deformation and failure in composite structures. Composites are required to resist ballistic impact loading to be used as protective structures. It is necessary to develop a simulation tool that can systematically calculate input parameters for the accurate simulation of both ballistic limit and damage patterns. In order to capture the complex composite material systems, a top-down approach will be merged with a bottom-up approach for modeling the ballistic limit and damage patterns in large scale textile composites. The top-down portion will use global strengths obtained from macro-scale coupon level testing to characterize the material strengths. The bottom-up portion will use micro-scale fiber and matrix stiffness properties to characterize the material stiffness. By combining these two approaches, all the micromechanical mechanisms can be captured without having to individually identify and characterize them. The combination will be an advantageous approach for modeling macro-scale composite structures because the micromechanical mechanisms can be accounted for even when using larger mesh sizes.
Mesostructured germanium with cubic pore symmetry

Regular mesoporous oxide materials have been widely studied and have a range of potential applications, such as catalysis, absorption and separation. They are not generally considered for their optical and electronic properties. Elemental semiconductors with nanopores running through them represent a different form of framework material with physical characteristics contrasting with those of the more conventional bulk, thin film and nanocrystalline forms. Here we describe cubic mesostructured germanium, MSU-Ge-1, with gyroidal channels containing surfactant molecules, separated by amorphous walls that lie on the gyroid (G) minimal surface as in the mesoporous silica MCM-48 (ref. 2). Although Ge is a high-melting, covalent semiconductor that is difficult to prepare from solution polymerization, we succeeded in assembling a continuous Ge network using a suitable precursor for Ge(4-) atoms. Our results indicate that elemental semiconductors from group 14 of the periodic table can be made to adopt mesostructured forms such as MSU-Ge-1, which features two three-dimensional labyrinthine tunnels obeying Ia3d space group symmetry and separated by a continuous germanium minimal surface that is otherwise amorphous. A consequence of this new structure for germanium, which has walls only one nanometre thick, is a wider electronic energy bandgap (1.4 eV versus 0.66 eV) than has crystalline or amorphous Ge. Controlled oxidation of MSU-Ge-1 creates a range of germanium suboxides with continuously varying Ge:O ratio and a smoothly increasing energy gap.
The Classical Moment Problem as a Self-Adjoint Finite Difference Operator

Abstract This is a comprehensive exposition of the classical moment problem using methods from the theory of finite difference operators. Among the advantages of this approach is that the Nevanlinna functions appear as elements of a transfer matrix and convergence of Pade approximants appears as the strong resolvent convergence of finite matrix approximations to a Jacobi matrix. As a bonus of this, we obtain new results on the convergence of certain Pade approximants for series of Hamburger
“Color-Tripole Ice” as a Conceptual Generalization of “Spin Ice”

“Spin Ice” is an exotic type of frustrated magnet realized in “pyrochlore” materials Ho2Ti2O7, Dy2Ti2O7, Ho2Sn2O7, and so forth, in which magnetic atoms (spins) reside on a sublattice made of the vertices of corner-sharing tetrahedra. Each spin is Ising-like with respect to a local axis which connects the centers of two tetrahedra sharing the vertex occupied by the spin. The macroscopically degenerate ground states of these magnets obey the “two-in two-out” “ice rule” within each tetrahedron. Magnetic monopoles and antimonopoles emerge as elementary excitations, “fractionalizing” the constituent magnetic dipoles. This system is also a novel type of statistical mechanical system. Here we introduce a conceptual generalization of “spin ice” to what we shall call “color-tripole ice,” in which three types of “color charges” can emerge as elementary excitations, which are Abelian approximations of the color charges introduced in high energy physics. Two two-dimensional (2D) models are introduced first, where the color charges are found to be 1D and constrained 2D, respectively. Generalizations of these two models to 3D are then briefly discussed. In the second one the color charges are likely 3D. Pauling-type estimates of the “residual (or zero-point) entropy” are also made for these models.
Bethesda classification of cervicovaginal smears: Reproducibility and viral correlates

Abstract Fifty-five cervicovaginal smears from women with squamous intraepithelial lesions (SILs) were independently evaluated on two separate occasions by four cytopathologists using a binary classification system (the Bethesda system). Smears were categorized as low-grade (LSIL) or high-grade (HSIL) using previously published criteria. All women had subsequent cervical biopsies containing human papillomavirus (HPV) DNA amplified with the polymerase chain reaction and typed by restriction fragment polymorphism analysis. Three or more observers agreed on classification in 49 of 55 cases (87%); unanimous diagnoses were rendered in 31 cases (56%). Interobserver and intraobserver reproducibility ranged from fair to near-excellent (κ values 0.40 to 0.63; 0.63 to 0.74, respectively). HPV types included HPV 16 (27%), 18 (7%), 31 (9%), 35 (4%), 39 (4%), 6 (10%), 11 (2%), novel types (30%), and multiple types (4%). High-risk HPV types (16, 18, 31, 35, and 39) were significantly associated ( P = .03) with consensus HSIL diagnoses (agreement of three or more observers). This was primarily because of the strong association of HPV 16 with HSIL ( P = .001). After excluding HPV 16, the other high-risk HPV types (18, 31, 35, and 39) were no longer significantly associated with consensus HSIL diagnoses ( P > .5). Conversely, LSIL diagnoses were significantly associated with non—high-risk HPV types (all HPV types except 16, 18, 31, 35, and 39; P = .006). Binary cytological classification of cervicovaginal SILs is reproducible among cytopathologists. Such classification correlates well with most low-risk HPV types and with the prototypic high-risk HPV 16 but not with other high-risk HPV types.
Region analysis: a parallel elimination method for data flow analysis

Parallel data flow analysis methods offer the promise of calculating detailed semantic information about a program at compile-time more efficiently than sequential techniques. Previous work on parallel elimination methods (Zobel, 1990) has been hampered by the lack of control over interval size; this can prohibit effective parallel execution of these methods. To overcome this problem, we have designed the region analysis method, a new elimination method for data flow analysis. Region analysis emphasizes flow graph partitioning to enable better load balancing in a more effective parallel algorithm. We present the design of region analysis and the empirical results we have obtained that indicate: the prevalence of large intervals in flow graphs derived from real programs; and the performance improvement of region analysis over parallel Allen-Cocke interval analysis. Our implementation analyzed programs from the Perfect Benchmarks and netlib running on a Sequent Symmetry S81. >
Further Evidence for an Elliptical Instability in Rotating Fluid Bars and Ellipsoidal Stars

Using a three-dimensional nonlinear hydrodynamic code, we examine the dynamical stability of more than 20 self-gravitating, compressible, ellipsoidal fluid configurations that initially have the same velocity structure as Riemann S-type ellipsoids. Our focus is on "adjoint" configurations, in which internal fluid motions dominate over the collective spin of the ellipsoidal figure; Dedekind-like configurations are among this group. We find that, although some models are stable and some are moderately unstable, the majority are violently unstable toward the development of m = 1, m = 3, and higher-order azimuthal distortions that destroy the coherent, m = 2 barlike structure of the initial ellipsoidal configuration on a dynamical timescale. The parameter regime over which our models are found to be unstable generally corresponds with the regime over which incompressible Riemann S-type ellipsoids have been found to be susceptible to an elliptical strain instability. We therefore suspect that an elliptical instability is responsible for the destruction of our compressible analogs of Riemann ellipsoids. The existence of the elliptical instability raises concerns regarding the final fate of neutron stars that encounter the secular bar-mode instability and regarding the spectrum of gravitational waves that will be radiated from such systems.
Cyclotron resonances of ions with obliquely propagating waves in coronal holes and the fast solar wind

[1] There is a growing consensus that cyclotron resonances play important roles in heating protons and ions in coronal holes where the fast solar wind originates and throughout interplanetary space as well. Most work on cyclotron resonant interactions has concentrated on the special, but unrealistic, case of propagation along the ambient magnetic field, B0, because of the great simplification it gives. This paper offers a physical discussion of how the cyclotron resonances behave when the waves propagate obliquely to B0. We show how resonances at harmonics of the cyclotron frequency come about, and how the physics can be different depending on whether E⟂ is in or perpendicular to the plane containing k and B0 (k is wave vector, and E⟂ is the component of the wave electric field perpendicular to B0). If E⟂ is in the k-B0 plane, the resonances are analogous to the Landau resonance and arise because the particle tends to stay in phase with the wave during the part of its orbit when it is interacting most strongly with E⟂. If E⟂ is perpendicular to the k-B0 plane, then the resonances depend on the fact that the particle is at different positions during the parts of its orbit when it is interacting most strongly with E⟂. Our main results are our equations (10), (11), and (13) for the secular rate of energy gain (or loss) by a resonant particle and the unfamiliar result that ions can resonate with a purely right-hand circularly polarized wave if the propagation is oblique. We conclude with some speculations about the origin of highly obliquely propagating ion resonant waves in the corona and solar wind. We point out that there are a number of instabilities that may generate such waves locally in the corona and solar wind.