cssi/SciSciGPT-SciSciNet huggingface dataset:
Theory and tests of two-phase turbines

A theoretical model for two-phase turbines was developed. Apparatus was constructed for testing one- and two-stage turbines (using speed decrease from stage to stage). Turbines were tested with water and nitrogen mixtures and refrigerant 22. Nozzle efficiencies were 0.78 (measured) and 0.72 (theoretical) for water and nitrogen mixtures at a water/nitrogen mixture ratio of 68, by mass; and 0.89 (measured) and 0.84 (theoretical) for refrigerant 22 expanding from 0.02 quality to 0.28 quality. Blade efficiencies (shaft power before windage and bearing loss divided by nozzle jet power) were 0.63 (measured) and 0.71 (theoretical) for water and nitrogen mixtures and 0.62 (measured) and 0.63 (theoretical) for refrigerant 22 with a single stage turbine, and 0,70 (measured) and 0.85 (theoretical) for water and nitrogen mixtures with a two-stage turbine.
PHOTO-EXCITED ZERO-RESISTANCE STATES IN THE GaAs/AlGaAs SYSTEM

The microwave-excited high mobility two-dimensional electron system exhibits, at liquid helium temperatures, vanishing resistance in the vicinity of B=[4/(4j+1)]Bf, where Bf=2πfm*/e, m* is an effec...
The Bayesian Bridge

Summary. We propose the Bayesian bridge estimator for regularized regression and classification. Two key mixture representations for the Bayesian bridge model are developed: a scale mixture of normal distributions with respect to an α-stable random variable; a mixture of Bartlett– Fejer kernels (or triangle densities) with respect to a two-component mixture of gamma random variables. Both lead to Markov chain Monte Carlo methods for posterior simulation, and these methods turn out to have complementary domains of maximum efficiency. The first representation is a well-known result due to West and is the better choice for collinear design matrices. The second representation is new and is more efficient for orthogonal problems, largely because it avoids the need to deal with exponentially tilted stable random variables. It also provides insight into the multimodality of the joint posterior distribution, which is a feature of the bridge model that is notably absent under ridge or lasso-type priors. We prove a theorem that extends this representation to a wider class of densities representable as scale mixtures of beta distributions, and we provide an explicit inversion formula for the mixing distribution. The connections with slice sampling and scale mixtures of normal distributions are explored. On the practical side, we find that the Bayesian bridge model outperforms its classical cousin in estimation and prediction across a variety of data sets, both simulated and real. We also show that the Markov chain Monte Carlo algorithm for fitting the bridge model exhibits excellent mixing properties, particularly for the global scale parameter. This makes for a favourable contrast with analogous Markov chain Monte Carlo algorithms for other sparse Bayesian models. All methods described in this paper are implemented in the R package BayesBridge. An extensive set of simulation results is provided in two on-line supplemental files.
The Role of Publication Selection Bias in Estimates of the Value of a Statistical Life

Meta-regression estimates of the value of a statistical life (VSL) controlling for publication selection bias often yield bias-corrected estimates of VSL that are substantially below the mean VSL e...
Breaking the Ties That Bind: From Corporate Sustainability to Socially Sustainable Systems

Although the recent push toward sustainability is certainly generally a positive development in business and society, we can see many problems in the execution of the theory of sustainability. Where the triple bottom line calls on companies to weigh effects on stakeholders and the environment alongside profit, in practice in many cases, sustainability has been perverted to represent sustainable profits. In these cases, environmental impact and effects on people are only important insofar as they positively contribute to a firm‘s future profits. It is not only practitioners who have often espoused this misappropriated view of sustainability but also academics have lent credibility to this view. In this work, we start by criticizing the often espoused current view of sustainability and remind academics of their responsibility to adapt a more critical view of this narrow focus. We provide examples that show how the current system of capitalism has resulted in outcomes for people and the environment that are patently unacceptable. Reasons are given as to why there is much hesitation to change the status quo. We then call on academics to reexamine what the role of businesses should be within society, what obligations business and corporations should have in society, and how we can encourage meaningful change that results in a better world for future generations.
Alkynyliodonium salts in organic synthesis. Development of a unified strategy for the syntheses of (-)-agelastatin A and (-)-agelastatin B.

The total syntheses of natural agelastatin A and agelastatin B were accomplished via a strategy that utilized an alkynyliodonium salt → alkylidenecarbene → cyclopentene transformation to convert a relatively simple amino alcohol derivative to the functionalized core of the agelastatin system. Subsequent manipulations delivered debromoagelastatin, which served as a precursor to both agelastatin A and agelastatin B. Alkylidenecarbene insertion chemoselectivity issues were explored en route to the final targets.
Failure insensitive routing for ensuring service availability

Intra-domain routing protocols employed in the Internet route around failed links by having routers detect adjacent link failures, exchange link state changes, and recompute their routing tables. Due to several delays in detection, propagation and recomputation, it may take tens of seconds to minutes after a link failure to resume forwarding of packets to the affected destinations. This discontinuity in destination reachability adversely affects the quality of continuous media applications such as Voice over IP. Moreover, the resulting service unavailability for even a short duration could be catastrophic in the world of e-commerce. Though careful tuning of the various parameters of the routing protocols can accelerate convergence, it may cause instability when the majority of the failures are transient. To improve the failure resiliency without jeopardizing the routing stability, we propose a local rerouting based approach called failure insensitive routing. Under this approach, upon a link failure, adjacent router suppresses global updating and instead initiates local rerouting. All other routers infer potential link failures from the packet's incoming interface, precompute interface specific forwarding We demonstrate that the proposed approach provides higher service availability than the existing routing schemes.
Efficient transient simulation of high-speed interconnects characterized by sampled data

In this paper, we present an algorithm for efficient simulation of high-speed interconnects characterized by sampled data. The method constructs pole-zero models of arbitrary interconnects using robust rational approximations of the measured or simulated scattering parameters. In order to obtain accurate interpolations of the data over a wide frequency range, a set of powerful techniques is applied to deal with the resulting ill-conditioned Vandermonde-like approximation matrices. By utilizing the analytic properties of the scattering parameters, the algorithm efficiently generates multiport pole-residue models. The models are combined with the lumped/distributed components for direct time- or frequency-domain simulations. The method can easily be implemented into conventional simulators such as simulation program with integrated circuit emphasis (SPICE) and advanced statistical analysis program (ASTAP) or reduced-order modeling techniques such as asymptotic waveform evaluation (AWE), complex frequency hopping (CFH), and Padd approximation via Lancros Process (PVL) for transient simulation of high-speed interconnect networks. Examples of linear and nonlinear networks are given to demonstrate the validity and accuracy of the method.
Evaluation of Time-Duration Dependent Wheel Load Criteria for Wheelclimb Derailment

This paper shows that the JNR and other time-duration dependent criteria based on wheel load measurements alone are unsuccessful in predicting derailment safety. For wheelclimb processes involving negligible lateral velocities, the derailment limit can be estimated from quasisteady analysis of wheel/rail forces. The evaluation of criteria is based on experiments with a single wheelset and a nonlinear theory for dynamic wheelclimb.
Investment Tax Incentives, Prices, and the Supply of Capital Goods

Using data on the prices of capital goods, this paper shows that much of the benefit of" investment tax incentives does not go to investing firms but rather to capital suppliers through" higher prices. The reduction in the cost of capital from a 10 percent investment tax credit" increases equipment prices 3.5-7.0 percent. This lasts several years and is largest for assets with" large order backlogs, low import competition, or with a large fraction of buyers able to use" investment subsidies. Capital goods workers' wages rise, too. Instrumental variables estimates" of the short-run supply elasticity are around 1 and can explain the traditionally small estimates of" investment demand elasticities. In absolute value, the demand elasticity implied here exceeds 1."
Random Homogenization of p-Laplacian with Obstacles in Perforated Domain

We study the homogenization of p-Laplacian with obstacles in perforated domain, where the holes are periodically distributed and have random size. And we assume that the p-capacity of each hole is stationary ergodic.
Indirect adaptive control for interconnected systems

An indirect adaptive controller for interconnected systems is introduced. Each subsystem is subject to bounded disturbances and to possibly unbounded interconnections with other subsystems. A variable dead zone is incorporated into a gradient estimation scheme to limit the effects of the interconnections and disturbances. An adaptive state feedback control law is described which stabilizes the interconnected system, forcing the input and output signals of each subsystem to remain bounded. >
An empirical equilibrium model of formal and informal credit markets in developing countries

In this paper, I develop and estimate a dynamic equilibrium model of household borrowing and savings decisions in formal and informal credit markets. The model features households with heterogeneities in productivity and wealth, and characterizes credit market access by interest rates, fixed costs, and borrowing constraints. Households have access to an exogenous formal credit market and to an informal credit market in which the interest rate is endogenously determined by the local demand and supply of credit. My application focuses on Thailand which implemented policies in 2001 that primarily encouraged borrowing. I estimate the model by simulated maximum likelihood using data from the Townsend Thai Monthly Survey. Based on the estimated model, I find that lower fixed costs increased the proportion of households borrowing formally, and that relaxed formal borrowing collateral constraints lowered informal interest rates. In terms of welfare, I find that low wealth but productive households benefited from Thai policies to expand credit access, but the gains were smaller than suggested by previous studies that ignored the informal market. Moreover, approximately 18% of households suffered welfare losses because of diminished opportunities for informal saving. Counterfactual policy simulations suggest that policies that combine borrowing and savings subsidies could yield higher average social welfare at a cost similar to the implemented policies.
Nanostructured materials for applications in heterogeneous catalysis

In this review, a brief survey is offered on the main nanotechnology synthetic approaches available to heterogeneous catalysis, and a few examples are provided of their usefulness for such applications. We start by discussing the use of colloidal, reverse micelle, and dendrimer chemistry in the production of active metal and metal oxide nanoparticles with well-defined sizes, shapes, and compositions, as a way to control the surface atomic ensembles available for selective catalysis. Next we introduce the use of sol–gel and atomic layer deposition chemistry for the production and modification of high-surface-area supports and active phases. Reference is then made to the more complex active sites that can be created or carved on such supports by using organic structure-directing agents. We follow with an examination of the ability to achieve multiple functionality in catalysis via the design of dumbbells, core@shell, and other complex nanostructures. Finally, we consider the mixed molecular-nanostructure approach that can be used to develop more demanding catalytic sites, by derivatizing the surface of solids or tethering or immobilizing homogeneous catalysts or other chemical functionalities. We conclude with a personal and critical perspective on the importance of fully exploiting the synergies between nanotechnology and surface science to optimize the search for new catalysts and catalytic processes.
Is physics in the infinite momentum frame independent of the compactification radius

Abstract With the aim of clarifying the eleven-dimensional content of Matrix theory, we examine the dependence of a theory in the infinite momentum frame (IMF) on the ppurely spatial) longitudinal compactification radius R . It is shown that in a point particle theory the generic scattering amplitude becomes independent of R in the IMF. Processes with zero longitudinal momentum transfer are found to be exceptional. The same question is addressed in a theory with extended objects. A one-loop type II string amplitude is shown to be R -independent in the IMF, and to coincide with that of the uncompantified theory. No exceptional processes exist in this case. The possible implications of these results for M theory are discussed. In particular, if amplitudes in M-theory are independent of R in the IMF, Matrix theory can be rightfully expected (in the N → ∞ limit) to describe uncompactified M-theory.
An options based bioeconomic model for biological and chemical control of invasive species

The management of non-native invasive species is a complex but crucial task given the potential for economic and environmental damages. For many invasions the development of socially optimal control strategies requires more than is offered by the single-species, single-control models that have dominated this area of research. We develop a general stochastic optimal control framework that accommodates multiple interacting species while accounting for uncertainty in the temporal population dynamics. This extension to the current line of bioeconomic control models allows for the design of optimal integrated pest management strategies that utilize both chemical and biological controls in an environment of uncertainty and irreversibility. We demonstrate the benefits of combining chemical and biological controls in long term management strategies through a case study of the hemlock wooly adelgid (Adelges tsugae) infestation in the eastern United States. In this application we find that the introduction of natural predators is usually sufficient to manage the infestation, though chemical insecticides can play an important role when detection of the infestation is delayed or when the biological control agent does not sufficiently increase mortality of the invasive species.
Microwave-promoted Suzuki coupling reactions with organotrifluoroborates in water using ultra-low catalyst loadings

The Suzuki reaction in water using parts per million concentrations of palladium is reported using potassium trifluoroborates as alternatives to boronic acids as substrates.
Studies on transannular rearrangement pathways in the bicyclo[4.4.1]undecane ring system: a novel entry into the bicyclo[4.2.1]nonene ring system

Abstract Several novel transannular bond reorganization pathways have been observed in various bicyclo[4.4.1]undecane substrates during attempted α-ketol and pinacol rearrangement reactions.
The social problem of automation

Rather than the announced title, the subject might more appropriately be: "Automation As It Has Demonstrably Affected Man's Working, Man's Playing, and Man's Thinking". The field of electronic computing which is today identified with automation, is now 10 years old. Consequently, there is no need for speculation concerning what might happen in the future. Rather, examine what has happened in the 10 years just past. Ten years ago it was thought that all manner of social problems might be created by the introduction of the electronic computer. In the light of experience, it can now be stated that given appropriate foresight and planning, the introduction of electronic computers can be accomplished in such a fashion that the fears of 10 years ago are proved groundless. Automation has extended man's capability as a worker and as a thinker.
A Combinatorial Proof of the Log-Concavity of the Numbers of Permutations with k Runs

We combinatorially prove that the number R(n,k) of permutations of length n having k runs is a log-concave sequence in k, for all n. We also give a new combinatorial proof for the log-concavity of the Eulerian numbers.
Comparison between methane and propylene as reducing agents in the SCR of NO over Pd supported on tungstated zirconia

It is now well known that when Pd is supported on acidic supports, it becomes highly selective for the reduction of NO by methane in the presence of excess oxygen. It is also known that this promoting effect not only occurs with acidic zeolite supports, but also with acidic zirconia supports, such as sulfated zirconia (SZ) and tungstated zirconias (WZ). However, this promoting effect has not been investigated for the SCR with other hydrocarbons as reducing agents. In this contribution, we have investigated the behavior of a series of Pd/WZ catalysts and compared them using methane and propylene as reducing agents. The results show some important differences when the reducing agent is changed. For example, while with CH4 the addition of W to the catalyst results in an increase in both NO and hydrocarbon conversion, with C3H6 it results in a decrease in activity. At the same time, while the presence of NO accelerates the activation of CH4, it inhibits the activation of C 3H6, moving its light-off to higher temperatures. Finally, an important difference between CH 4 and C3H6 as reducing agents is regarding the selectivity towards N2 as opposed to N2O. Using CH4 resulted in much lower production of N2O than using C3H6, over the entire temperature range investigated. © 2000 Published by Elsevier Science B.V.
Trade Wars and Trade Talks with Data

How large are optimal tariffs? What tariffs would prevail in a worldwide trade war? How costly would a breakdown of international trade policy cooperation be? And what is the scope for future multilateral trade negotiations? I address these and other questions using a unified framework which nests traditional, new trade, and political economy motives for protection. I find that optimal tariffs average 62 percent, world trade war tariffs average 63 percent, the government welfare losses from a breakdown of international trade policy cooperation average 2.9 percent, and the possible government welfare gains from future multilateral trade negotiations average 0.5 percent. (JEL F12, F13, O19) I propose a flexible framework for the quantitative analysis of noncooperative and cooperative trade policy. It is based on a multi-country multi-industry general equilibrium model of international trade featuring inter-industry trade as in Ricardo (1817), intra-industry trade as in Krugman (1980), and special interest politics as in Grossman and Helpman (1994). By combining these elements, it takes a unified view of trade policy which nests traditional, new trade, and political economy motives for protection. Specifically, it features import tariffs which serve to manipulate the terms-of-trade, shift profits away from other countries, and protect politically influential industries. It can be easily calibrated to match industry-level tariffs and trade. I use this framework to provide a first comprehensive quantitative analysis of noncooperative and cooperative trade policy, focusing on the main players in recent GATT/WTO negotiations. I begin by considering optimal tariffs, i.e., the tariffs countries would impose if they did not have to fear any retaliation. I find that each country can gain considerably at the expense of other countries by unilaterally imposing optimal tariffs. In the complete version with lobbying, the mean welfare gain of the tariff imposing government is 1.9 percent, the mean welfare loss of the other governments is −0.7 percent, and the average optimal tariff is 62.4 percent.
Remittances, Household Expenditure and Investment in Guatemala

The author uses a large household data set from Guatemala to analyze how the receipt of internal remittances (from Guatemala) and international remittances (from the United States) affects the marginal spending behavior of households on various consumption and investment goods. Contrary to other studies, the author finds that households receiving remittances actually spend less at the margin on consumption-food and consumer goods and durables-than do households receiving no remittances. Instead of spending on consumption, households receiving remittances tend to spend more on investment goods, like education, health, and housing. The analysis shows that a large amount of remittance money goes into education. At the margin, households receiving internal and international remittances spend 45 and 58 percent more, respectively, on education, than do households with no remittances. These increased expenditures on education represent investment in human capital. Like other studies, the author finds that remittance-receiving households spend more at the margin on housing. These increased expenditures on housing represent a type of investment for the migrant, as well as a means for boosting local economic development by creating new income and employment opportunities for skilled and unskilled workers.
Synthesis of Annulated γ-Carbolines and Heteropolycycles by the Palladium-Catalyzed Intramolecular Annulation of Alkynes

A variety of N-substituted 2-bromo-1H-indole-3-carboxaldehydes incorporating an alkyne-containing tether on the indole nitrogen have been converted to the corresponding tert-butylimines, which have been subjected to palladium-catalyzed intramolecular iminoannulation, affording various gamma-carboline derivatives with an additional ring fused across the 4- and 5-positions in good to excellent yields. When the tethered carbon-carbon triple bond is terminal or substituted with a triethylsilyl group, the iminoannulation generates a tert-butyl-gamma-carbolinium salt as the major product. The palladium-catalyzed intramolecular annulations of N-substituted 2-bromo-1H-indole-3-carboxaldehyde, methyl 2-iodo-1H-indole-3-carboxylate, and 2-iodo-3-phenyl-1H-indole containing a phenylpentynyl tether produce the corresponding heteropolycycles in moderate to good yields.
Quantization bounds on Grassmann manifolds of arbitrary dimensions and MIMO communications with feedback

This paper considers the quantization problem on the Grassmann manifold with dimension n and p. The unique contribution is the derivation of a closed-form formula for the volume of a metric ball in the Grassmann manifold when the radius is sufficiently small. This volume formula holds for Grassmann manifolds with arbitrary dimension n and p, while previous results are only valid for either p = 1 or a fixed p with asymptotically large n. Based on the volume formula, the Gilbert-Varshamov and Hamming bounds for sphere packings are obtained. Assuming a uniformly distributed source and a distortion metric based on the squared chordal distance, tight lower and upper bounds are established for the distortion rate tradeoff. Simulation results match the derived results. As an application of the derived quantization bounds, the information rate of a multiple-input multiple-output (MIMO) system with finite-rate channel-state feedback is accurately quantified for arbitrary finite number of antennas, while previous results are only valid for either multiple-input single-output (MISO) systems or those with asymptotically large number of transmit antennas but fixed number of receive antennas.
Impact of Information Technology Capital on Firm Scope and Performance: The Role of Asset Characteristics

This research draws on transaction cost and resource-based theory to examine how information technology (IT) capital moderates the relationship between different types of assets and firm scope--both vertical integration and diversification. The analysis suggests that IT capital enables firms with narrowly valuable assets to be less vertically integrated and less diversified, and enables firms with broadly valuable assets to be more vertically integrated and more diversified. The moderating influence of IT capital on the relationship between different types of assets and firms' vertical and product-market scope is consistent with transaction cost as well as resource-based traditions. [ABSTRACT FROM AUTHOR]
Lifting Fan Noise Studies with Superimposed Cross Flows

Experimental studies on noise radiation from a single-stage lifting fan operating at subsonic tip speeds are described. The effects on noise radiation of inlet flow distortion as a result of superimposed cross flow are presented. Under zero cross-flow conditions, narrow band analysis of the results shows the presence of discrete "shaft order tones," in addition to high-level tones at blade-passing frequencies at a subsonic tip speed of 628 fps. Propagating modes of these tones are identified with some reasonable success based on observed directivity patterns, using Tyler and Sofrin's radiation formula. Only the shaft orders at multiples of stator blade numbers giving a plane wave radiation are in evidence at lower fan speeds. Under cross-flow conditions, there is an increase of up to 10 db in the level of broadband noise. The shaft order tones become less conspicuous because of this rise in broadband noise. The radiation patterns of blade-passing tones show strong dependence on the cross flow. An unexpected reduction in peak blade-passing tone levels at some conditions of cross flow suggests the two interaction mechanisms, inflow distortion with rotor and rotor with stator, are interdependent.
GLOBAL WELL-POSEDNESS FOR THE MICROSCOPIC FENE MODEL WITH A SHARP BOUNDARY CONDITION

Abstract We prove global well-posedness for the microscopic FENE model under a sharp boundary requirement. The well-posedness of the FENE model that consists of the incompressible Navier–Stokes equation and the Fokker–Planck equation has been studied intensively, mostly with the zero flux boundary condition. In this article, we show that for the well-posedness of the microscopic FENE model ( b > 2 ) the least boundary requirement is that the distribution near boundary needs to approach zero faster than the distance function. Under this condition, it is shown that there exists a unique weak solution in a weighted Sobolev space. Moreover, such a condition still ensures that the distribution is a probability density. The sharpness of this boundary requirement is shown by a construction of infinitely many solutions when the distribution approaches zero no faster than the distance function.
How Black Holes turn Cusps into Cores

Collapsing collisionless particle systems form gravitational bound halos with cuspy density profiles. Also hierarchical merging of these systems produce remnants with cuspy central density profiles. These results lead to the assumption of cuspy NFW (Navarro et al., 1996) profiles for the density distribution in dark matter halos. However, observed rotation curves in disk galaxies suggest dark matter halos with isothermal cores. The same kind of problem can be found for globular clusters, which show cores in their density profiles but should be cuspy if they where formed through a cold collapse(King, 1962; Jenkins et al., 1998). We are showing how small, massive, and compact objects can efficiently transform cuspy stellar systems into density profiles with an isothermal core.
Air extraction in a gas turbine for integrated gasification combined cycle (IGCC): Experiments and analysis

This paper presents an investigation of extracting air from the compressor discharge of a heavy-frame gas turbine. The study aimed to verify results of an approximate analysis: whether extracting air from the turbine wrapper would create unacceptable nonuniformity in the flow field inside the compressor discharge casing. A combined experimental and computational approach was undertaken. Cold flow experiments were conducted in an approximately one-third scale model of a heavy-frame gas turbine; a closely approximated three-dimensional computational fluid dynamic analysis was also performed. This study substantiated the earlier prediction that extracting air from the turbine wrapper would be undesirable, although this method of air extraction is simple to retrofit. Prediffuser inlet is suggested as an alternate location for extracting air. The results show that not only was the problem of flow nonuniformity alleviated with this alternate scheme, but the frictional power loss in the compressor discharge casing was also reduced by a factor of two.
Generalized slow-roll conditions and the possibility of intermediate scale inflation in scalar-tensor theory

Generalized slow-roll conditions and parameters are obtained for a general form of scalar-tensor theory (with no external sources), having arbitrary functions describing a non-minimal gravitational coupling F(), a Kahler-like kinetic function k(), and a scalar potential V(). These results are then used to analyse a simple toy model example of chaotic inflation with a single scalar field and a standard Higgs potential and a simple gravitational coupling function. In this type of model inflation can occur with inflaton field values at an intermediate scale of roughly 1011 GeV when the particle physics symmetry-breaking scale is approximately 1 TeV, provided that the theory is realized within the Jordan frame. If the theory is realized in the Einstein frame, however, the intermediate scale inflation does not occur.
Inter-calibration of the CMS barrel electromagnetic calorimeter using π 0 → γγ decays

Inter-calibrating the electromagnetic calorimeter (ECAL) of the CMS detector in situ at the LHC to achieve the energy resolution approaching 0.5% at high energy is going to be important to fully exploit the physics reach of the detector, particularly for the discovery of the Higgs boson in the two-photon decay channel. In this paper we evaluate the potential of a calibration technique that makes use of photon pairs produced in neutral pion decays, π0 → γγ. Such photon pairs will be selected from the QCD events accepted by the Level-1 triggers using an online filter farm. Assuming a Level-1 trigger rate of 12.5 kHz, the rate of suitable neutral pions is found to be about 0.9 kHz. We show that 95% of the barrel electromagnetic calorimeter can be calibrated to at least a 1% (0.5%) precision after several days (weeks) of data-taking in the low-luminosity scenario of LHC, L = 2 · 1033, cm−2 s−1. In addition, we report on the successful tests of the π0 reconstruction and calibration algorithms that were carried out using π0 → γγ decays produced in π− test beams in November 2006.
The Effect Of Alpha-Element Enhancement On Surface Brightness Fluctuation Magnitudes And Broad-Band Colors

We present the effects due to alpha-element enhancement on surface brightness fluctuation magnitudes and broad-band colors in order to investigate the calibration zero-point. We study these effects at ages covering 0.1 to 13 Gyr and metallicities of Z=0.0003 to 0.04 using the Teramo group's isochrones, BaSTI. Our preliminary results indicate that alpha-enhanced models are needed to match massive red galaxies while solar-scaled models are fine for dwarf blue galaxies to reproduce their independently estimated ages and metallicities.
Propulsion options for space-based orbital transfer vehicles

A concept for a lightweight space-based orbital transfer vehicle (OTV) featuring thin, spherical, pressuredesigned aluminum liquid-oxygen and liquid-hydrogen tanks and a truss structure of composite materials is used as a baseline design for a large-cargo OTV. Vehicle sizing, fleet analysis, and parametric cost analysis are used to evaluate the effects of engine technology, vehicle staging, and high-thrust vs. low-thrust transfer. Results indicate that Earth-to-orbit launch costs and OTV engine performance are strong drivers in orbital transportation cost and that there is no significant benefit in staging vehicles. At the low values of Earth-to-orbi t cost representative of advanced launch vehicles, low-thrust and high-thrust OTV's are competitive.
No Evidence of Impaired Neurocognitive Performance in Collegiate Soccer Players

A high incidence of cerebral concussion has been reported among soccer players. We studied whether long-term or chronic neuropsychological dysfunction was present in collegiate soccer players. Two hundred forty subjects from a National Collegiate Athletic Association division I institution were stratified into three groups: soccer athletes (91), nonsoccer athletes (96 women's field hockey, women's lacrosse, and baseball players), and controls (53 college students). Subjects completed a concussion history questionnaire and underwent preseason baseline neuropsychological testing before the start of either the freshman or sophomore year. Data were collected on the results of six neuropsychological tests and from a concussion history questionnaire for number of previous concussions, Scholastic Aptitude Test results, and exposure to soccer and heading. Despite an average of 15.3 seasons of soccer exposure and a higher prevalence of previous concussions, the soccer athletes did not demonstrate impaired neurocognitive function or scholastic aptitude when compared with the nonsoccer athletes or the student nonathletes. Additionally, there was no significant relationship between a history of soccer-related concussion and either neurocognitive performance or scholastic aptitude. Neither participation in soccer nor a history of soccer-related concussions was associated with impaired performance of neurocognitive function in high-level United States soccer players.
Effective search of the energy landscape for protein folding

We propose a new algorithmic approach for global optimization in protein folding. We use the information found in various local minima to direct the search for the global minimum. In this way, we explore the energy landscape efficiently by considering only the space of local minima instead of the whole feasible space of conformations.
What happened to and in Detroit

The paper describes the fiscal status of the city of Detroit leading up to its filing for bankruptcy on 18 July 2013. Then the economic history of metropolitan Detroit and the city of Detroit from ...
Interpretation of High Energy p-p Scattering.

High energy p-p scattering has been interpreted by several authors in terms of highly singular noncentral interactions. The triplet state calculations were carried out in the Born approximation and, together with the singlet, yielded an almost isotropic (c.m. system) differential cross section. Agreement with experiment was good at large angles but the theoretical peak in the forward direction, due mostly to singlet d scattering, was too large. It is not clear however that the Born approximation should be valid for singular potentials.
Pricing and Efficiency in the Market for IP Addresses

We consider market rules for transferring IP addresses, numeric identifiers required by all computers connected to the Internet. Transfers usefully move resources from lowest- to highest-valuation networks, but transfers tend to cause socially costly growth in the Internet's routing table. We propose a market rule that avoids excessive trading and comes close to achieving social efficiency. We argue that this rule is feasible despite the limited powers of central authorities. We also offer a framework for reasoning about future prices of IP addresses, then explore the role of rentals in sharing information about the value of IP address and assuring allocative efficiency. (JEL D47, D82, D85, L86)
Toward the automatic control of robot assembly tasks via potential functions: the case of 2-D sphere assemblies

An approach to the problem of controlling automated assembly tasks using artificial potential functions is described. The authors address the automatic generation of actuator commands for a robot manipulator that result in the motion of a collection of rigid-body parts from disassembled initial configurations to an assembled final configuration. A simple class of tasks, 2D sphere assemblies, is examined. A primitive constructive theory for the control of this class of tasks is presented. Preliminary computer simulations demonstrate that the proposed approach may provide surprisingly good performance. >
Yang-Mills and D-instantons

In this paper, which is written at an elementary and pedagogical level, we discuss general aspects of (single) instantons in SU(N) Yang-Mills theory, and then specialize to the case of = 4 supersymmetry and the large-N limit. We show how to determine the measure of collective coordinates and compute instanton corrections to certain correlation functions. We then relate this to D-instantons in type IIB supergravity. By taking the D-instantons to live in an AdS5×S5 background, we perform explicit checks of the AdS-CFT correspondence.
A Four-Parameter Iwan Model for Lap-Type Joints

The constitutive behavior of mechanical joints is largely responsible for the energy dissipation and vibration damping in built-up structures. For reasons arising from the dramatically different length scales associated with those dissipative mechanisms and the length scales characteristic of the overall structure, this physics cannot be captured through direct numerical simulation (DNS) of the contact mechanics within a structural dynamics analysis. The difficulties of DNS manifest themselves either in terms of Courant times that are orders of magnitude smaller than that necessary for structural dynamics analysis or as intractable conditioning problems. The only practical method for accommodating the nonlinear nature of joint mechanisms within structural dynamic analysis is through constitutive models employing degrees of freedom natural to the scale of structural dynamics. In this way, development of constitutive models for joint response is a prerequisite for a predictive structural dynamics capability. A four-parameter model, built on a framework developed by Iwan, is used to reproduce the qualitative and quantitative properties of lap-type joints. In the development presented here, the parameters are deduced by matching joint stiffness under low load, the force necessary to initiate macroslip, and experimental values of energy dissipation in harmonic loading. All the necessary experiments can be performed on real hardware or virtually via fine-resolution, nonlinear quasistatic finite elements. The resulting constitutive model can then be used to predict the force/displacement results from arbitrary load histories.
Prospects for detection of catastrophic collisions in debris disks

We investigate the prospects for detecting dust from two-body collisions during the late stages of planet formation at 1–150 AU. We develop an analytic model to describe the formation of a dusty cloud of debris and use numerical coagulation and N-body calculations to predict observable signals from these events. In a minimum mass solar nebula, collisions of 100–1000 km objects at distances of 3–5 AU or less from the parent star are observable at mid-IR wavelengths as bright clumps or rings of dust. At 24 μm, the clumps are ~0.1–1 mag brighter than emission from dust in the background debris disk. In edge-on systems, dusty clumps produce eclipses with depths of 1.0 mag that last for ~100 orbital periods. Large-scale surveys for transits from exosolar planets, using satellites such as Kepler, can plausibly detect these eclipses and provide important constraints on the terrestrial environment for ages of 100–300 Myr.
Estimating Relative Permeability From Production Data: A Streamline Approach

One of the outstanding challenges in reservoir characterization is to build high-resolution reservoir models that satisfy static as well as dynamic data. Integration of dynamic data so far has mainly focused on estimating spatial distribution of absolute permeability. Among the various properties important for simulating reservoir behavior, the relative permeability curves may be by far the most poorly determined by present methods. Estimation of relative permeability simultaneously with absolute permeability is a strongly nonlinear and ill-posed estimation problem. In this paper we present a streamline-based approach for estimating relative permeabilities from production data. The streamline approach offers two principal advantages. First, we can analytically compute the sensitivity of the production response with respect to relative permeability parameters. The approach is extremely fast and requires a single streamline simulation run. Second, we can exploit the analogy between streamlines and seismic ray tracing to develop a formalism for efficient inversion of production data. Thus, estimation of relative permeabilities is carried out in two steps: (i) matching of breakthrough or first arrival times and (ii) matching of amplitudes of the production response. For relative permeability representations we have used the commonly used power functions and also a more flexible representation through the use of B-splines. The relative advantages of these representations are examined through inversions of water-cut data from a nine-spot pattern. Finally, we address the underlying challenges associated with the simultaneous estimation of absolute and relative permeabilities from production data. We systematically investigate the non-uniqueness associated with the inverse problem and quantitatively evaluate the role of additional data
Performance of Coordinating Concurrent Hierarchical Planning Agents Using Summary Information

Recent research has provided methods for coordinating the individually formed concurrent hierarchical plans (CHiPs) of a group of agents in a shared environment. A reasonable criticism of this technique is that the summary information can grow exponentially as it is propagated up a plan hierarchy. This paper analyzes the complexity of the coordination problem to show that in spite of this exponential growth, coordinating CHiPs at higher levels is still exponentially cheaper than at lower levels. In addition, this paper offers heuristics, including "fewest threats first" (FTF) and "expand most threats first" (EMTF), that take advantage of summary information to smartly direct the search for a global plan. Experiments showthat for a particular domain these heuristics greatly improve the search for the optimal global plan compared to a "fewest alternatives first" (FAF) heuristic that has been successful in Hierarchical Task Network (HTN) Planning.
Code aperture optimization for spectrally agile compressive imaging

Coded aperture spectral imaging (CASSI) provides a mechanism to capture a 3D spectral cube with a single shot 2D measurement. This paper extends the concept of CASSI to a system admitting multiple shot measurements which leads not only to higher quality of reconstruction, but also to spectrally selective imaging when the sequence of code aperture patterns is optimized. The aperture code optimization problem is shown to be analogous to the optimization of a constrained, multichannel filter bank. The optimal code apertures allow the decomposition of the CASSI measurements into several matrices, each having compressive information from only a few selected spectral bands. Each matrix is reconstructed separately and the results are merged if the full data cube is needed. This technique is equivalent to a filter bank decomposition of the CASSI measurements. The approach shows better quality and higher speed of reconstruction than a non-optimized multishot CASSI system. A number of simulations are developed to illustrate the spectral imaging characteristics attained by optimal aperture codes.
On Nominal Delay Minimization in LUT-Based FPGA Technology Mapping

We study the nominal delay minimization problemin LUT-based FPGA technology mapping, where interconnect delay is assumed proportional to net fanout size. We prove that the delay-optimal K-LUT mapping problem under the nominal delay model is NP-hard when K ≥ 3, and remains NP-hard for duplication-free mapping and tree-based mapping for K ≥ 5 (but is polynomial time solvable for K = 2). We also present a simple heuristic to take nominal delay into consideration during LUT mapping for delay minimization.
Minority Status and Managerial Survival in Major League Baseball

The effect of minority status on managerial survival in Major League Baseball is analyzed using survival time analysis and data envelopment analysis. Efficiency scores based on team performance and player salary data from 1985 to 2006 are computed and included as covariates in a survival time analysis. It is shown that when controlling for performance and personal characteristics minorities are on average 9.6% points more likely to return the following season. Additionally, it is shown that winning percentage has no impact on managerial survival when efficiency is controlled for.
Evaluating discrete choice prediction models when the evaluation data is corrupted: analytic results and bias corrections for the area under the ROC

There has been a growing recognition that issues of data quality, which are routine in practice, can materially affect the assessment of learned model performance. In this paper, we develop some analytic results that are useful in sizing the biases associated with tests of discriminatory model power when these are performed using corrupt ("noisy") data. As it is sometimes unavoidable to test models with data that are known to be corrupt, we also provide some guidance on interpreting results of such tests. In some cases, with appropriate knowledge of the corruption mechanism, the true values of the performance statistics such as the area under the ROC curve may be recovered (in expectation), even when the underlying data have been corrupted. We also provide estimators of the standard errors of such recovered performance statistics. An analysis of the estimators reveals interesting behavior including the observation that "noisy" data does not "cancel out" across models even when the same corrupt data set is used to test multiple candidate models. Because our results are analytic, they may be applied in a broad range of settings and this can be done without the need for simulation.