cssi/SciSciGPT-SciSciNet huggingface dataset:
Is there a lowest upper bound for superconductive transition temperatures

Abstract I show that for high temperature ceramic cuprates there is a smooth master curve T c max ( 〈 R 〉 ) for the highest superconductive transition temperatures T c ’s as a function of the average number 〈 R 〉 of Pauling resonating bonds/atom in the parent (undoped) insulator. The existence of such an 〈 R 〉-dependent optimized T c is suggested by analogies with the microscopic theory of optimized molecular glass networks (such as window glass). The chemical model is part of a larger nanoscopically mixed multiphase structural model that also explains the canonical cuprate phase diagrams, as well as recent dynamical fs pump/ps probe optical relaxation experiments.
Matrix Completion in Colocated MIMO Radar: Recoverability, Bounds & Theoretical Guarantees

It was recently shown that low rank Matrix Completion (MC) theory can support the design of new sampling schemes in the context of MIMO radars, enabling significant reduction of the volume of data required for accurate target detection and estimation. Based on the data received, a matrix can be formulated, which can then be used in standard array processing methods for target detection and estimation. For a small number of targets relative to the number of transmission and reception antennas, the aforementioned data matrix is low-rank and thus can be recovered from a small subset of its elements using MC. This allows for a sampling scheme that populates the data matrix in a uniformly sparse fashion. This paper studies the applicability of MC theory on the type of data matrices that arise in colocated MIMO radar systems. In particular, for the case in which uniform linear arrays are considered for transmission and reception, it is shown that the coherence of the data matrix is both asymptotically and approximately optimal with respect to the number of antennas, and further, the data matrix is recoverable using a subset of its entries with minimal cardinality. Sufficient conditions guaranteeing low matrix coherence and consequently satisfactory matrix completion performance are also presented. These results are then generalized to the arbitrary 2-dimensional array case, providing more general but yet easy to use sufficient conditions ensuring low matrix coherence.
Cloud profiling radar for the CloudSat mission

The cloud profiling radar (CPR) for the upcoming CloudSat mission is a spaceborne 94-GHz nadir-looking radar that measures the power backscattered by clouds as a function of distance from the radar. This sensor is expected to provide cloud measurements at a 500-m vertical resolution and a 1.5-km horizontal resolution. CPR operates in a short-pulse mode and yields measurements at a minimum detectable sensitivity of-28 dBZ.
Quotient Types: A Modular Approach

In this paper we introduce a new approach to axiomatizing quotient types in type theory. We suggest replacing the existing monolithic rule set by a modular set of rules for a specially chosen set of primitive operations. This modular formalization of quotient types turns out to be much easier to use and free of many limitations of the traditional monolithic formalization. To illustrate the advantages of the new approach, we show how the type of collections (that is known to be very hard to formalize using traditional quotient types) can be naturally formalized using the new primitives. We also show how modularity allows us to reuse one of the new primitives to simplify and enhance the rules for the set types.
Local features of the Fermi surface curvature and the anomalous skin effect in metals

In this paper we present a theoretical analysis of the effect of local geometrical structure of the Fermi surface on the surface impedance of a metal under the anomalous skin effect. We show that when the Fermi surface includes nearly cylindrical and/or flattened segments it may significantly change both the magnitude and frequency dependence of the surface impedance. Being observed in experiments these unusual frequency dependences could bring additional information concerning fine geometrical features of the Fermi surfaces of metals.
Management objectives and the causes of mass transit deficits

Based on data for the period from 1948 to 1997, exogenous decreases in demand and increases in costs are estimated to have reduced the annual profitability of the Chicago Transit Authority (CTA) by $1 billion. Half of this decline was recouped by reductions in service, increased fares and increased productivity. Even more would have been recouped had the CTA not given away earlier productivity gains during the 1970s. This was during a period when subsidies were increasing rapidly, and seemingly without constraint. When faced with financial challenges, management has preferred to increase fares rather than reduce service levels to the detriment of social welfare. 2003 Elsevier Ltd. All rights reserved.
Geometry-Aware Deep Transform

Many recent efforts have been devoted to designing sophisticated deep learning structures, obtaining revolutionary results on benchmark datasets. The success of these deep learning methods mostly relies on an enormous volume of labeled training samples to learn a huge number of parameters in a network, therefore, understanding the generalization ability of a learned deep network cannot be overlooked, especially when restricted to a small training set, which is the case for many applications. In this paper, we propose a novel deep learning objective formulation that unifies both the classification and metric learning criteria. We then introduce a geometry-aware deep transform to enable a non-linear discriminative and robust feature transform, which shows competitive performance on small training sets for both synthetic and real-world data. We further support the proposed framework with a formal (K,&#x03B5;)-robustness analysis.
ON SASAKIAN–EINSTEIN GEOMETRY

We introduce a multiplication ⋆ (we call it a join) on the space of all compact Sasakian-Einstein orbifolds and show that has the structure of a commutative associative topological monoid. The set of all compact regular Sasakian–Einstein manifolds is then a submonoid. The set of smooth manifolds in is not closed under this multiplication; however, the join of two Sasakian–Einstein manifolds is smooth under some additional conditions which we specify. We use this construction to obtain many old and new examples of Sasakain–Einstein manifolds. In particular, in every odd dimension greater that five we obtain spaces with arbitrary second Betti number.
An XML based access control architecture for pervasive computing

There is a huge prevalence of mobile devices being connected to the Internet because of high demands for information access and dissemination. It is now well understood that XML plays a vital role as a means for information representation, exchange, and storage. Naturally, XML data is exchanged and stored as these mobile devices communicate with each other, and over the web. A major concern for one device requesting data (objects, services or raw data) from another device is security. Access control policies are important models that control access to data for authorized devices. In an XML setting, access control policies are necessary to control access to parts of XML documents. It becomes challenging in pervasive computing environment as the devices have small memory foot print, disconnection, low battery powers, etc. In this paper, we propose an XML based access control along with cryptography for secure transmission of XML data in pervasive environments.
Mesoionic Carbene‐Gold(I) Catalyzed Bis‐Hydrohydrazination of Alkynes with Parent Hydrazine

A novel synthetic route gives access to mesoionic carbene and cyclopropenylidene supported gold chloride complexes. The corresponding cationic MIC-gold complex obtained by chloride abstraction allows for the first transition metal-catalyzed functionalization of both nitrogens of parent hydrazine.
Fault-tolerant switched reluctance motor drive using adaptive fuzzy logic controller

An adaptive fuzzy controller has been designed to develop a high-performance fault-tolerant switched reluctance motor (SRM) drive. The fuzzy controller continuously adapts its properties to regulate the machine torque as desired by the drive system even under fault conditions. The adaptation of the fuzzy membership functions results in extended conduction period and increased peak current of the healthy phases to deliver the commanded torque, as much as possible. The adaptive fuzzy controller provides smooth torque output with minimum ripple, even under fault conditions, yielding a high-performance SRM drive with fault-tolerant capability.
Tracing Galaxy Formation with Stellar Halos. I. Methods

If the favored hierarchical cosmological model is correct, then the Milky Way system should have accreted � 100– 200 luminous satellite galaxies in the past � 12 Gyr. We model this process using a hybrid semianalytic plus N-body approach that distinguishes explicitly between the evolution of light and dark matter in accreted satellites. This distinction is essential to our ability to produce a realistic stellar halo, with mass and density profile much like that of our own Galaxy, and a surviving satellite population that matches the observed number counts and structural parameter distributions of the satellite galaxies of the Milky Way. Our accreted stellar halos have density profiles that typically drop off with radius faster than the dark matter and follow power laws at rk30 kpc with � / r � � , � ’ 3 4. They are well fit by Hernquist profiles over the full radial range. We find that stellar halos are assembled from the inside out, with the majority of mass (� 80%) coming from the � 15 most massive accretion events. The satellites that contributetothestellarhalohavemedianaccretiontimes of � 9Gyrinthepast,whilesurvivingsatellitesystems have median accretion times of � 5 Gyr in the past. This implies that stars associated with the inner halo should be quite differentchemicallyfromstarsinsurvivingsatellitesandalsofromstarsintheouterhaloorthoseliberatedinrecent disruptionevents.Webrieflydiscusstheexpectedspatialstructureandphase-spacestructureforhalosformedinthismanner. Searches for this type of structure offer a direct test of whether cosmology is indeed hierarchical on small scales. Subject headingg dark matter — galaxies: dwarf — galaxies: evolution — galaxies: formation — galaxies: halos — galaxies: kinematics and dynamics — Galaxy: evolution — Galaxy: formation — Galaxy: halo — Galaxy: kinematics and dynamics — Local Group
SPECTRAL FORMATION IN X-RAY PULSARS: BULK COMPTONIZATION IN THE ACCRETION SHOCK

Accretion-powered X-ray pulsars are among the most luminous X-ray sources in the Galaxy. However, despite decades of theoretical and observational work since their discovery, no satisfactory model for the formation of the observed X-ray spectra has emerged. In particular, the previously available theories are unable to reproduce the power-law variation observed at high energies in many sources. In this paper we present the first self-consistent calculation of the spectrum emerging from a pulsar accretion column that includes an explicit treatment of the energization occurring in the shock. Using a rigorous eigenfunction expansion method based on the exact dynamical solution for the velocity profile in the column, we obtain a closed-form expression for the Green's function describing the upscattering of radiation injected into the column from a monochromatic source located at the top of the thermal mound, near the base of the flow. The Green's function is convolved with a Planck distribution to calculate the radiation spectrum resulting from the reprocessing of blackbody photons emitted by the thermal mound. We demonstrate that the energization of the photons in the shock naturally produces an X-ray spectrum with a power-law shape at high energies and a blackbody shape at low energies, in agreement with many observations of accreting X-ray pulsars.
Sources of alliance partner trustworthiness: Integrating calculative and relational perspectives

Research on the sources of organizational trustworthiness remains bifurcated. Some scholars have adopted a calculative perspective, stressing the primacy of actors' rational calculations, while others have approached trustworthiness from a relational perspective, focusing on its social underpinnings. We help to reconcile these seemingly disparate views by adopting an integrative approach that allows us to clarify the boundaries of both perspectives. Based on dyadic survey data from 171 strategic alliances, we find that the calculative perspective (represented by contractual safeguards) has higher predictive power when the partner lacks a favorable reputation. In contrast, the relational perspective (represented by organizational culture) predicts trustworthiness more strongly when familiarity with the partner organization is high.
Enabling Confidentiality of Data Delivery in an Overlay Broadcasting System

In this paper, we present an extensive study of key dissemination schemes in an overlay multicast context, and the first to involve actual implementation, real traces, and performance in Internet environments. Given that rekey traffic has stronger resilience requirements and is burstier than data traffic, we consider whether data and keys must be distributed using the same overlay or using two separate dissemination structures. Our key findings are: (i) a coupled architecture is effective in achieving resilient key dissemination. Using TCP in each hop of the dissemination structure (an opportunity unique to overlays) is effective in achieving resiliency in end-to-end key delivery. The performance can be further enhanced if convergence properties of overlays are considered; and (ii) a coupled architecture optimized for data delivery has high overheads, while a coupled architecture optimized for key delivery may not honor access bandwidth constraints of nodes. Distributing data and keys using separate overlays achieves low overhead for key dissemination while honoring access bandwidth constraints of nodes.
Subacute toxicity of radioactive phosphorus as related to the composition of the diet.

SummaryIn mice on a 10% casein, 32% fat diet, the LD50 dose at the 21st day lies between 4 and 6 microcuries per g of body weight. Neither the fatty infiltration of the liver (induced by a deficiency of lipotropic factors, with or without partial poisoning with OCl4), or its prevention (by supplementing the diet with choline) changes the survival figures. The time of 50% deaths, the percentage of survivors at the 21st day and the average survival time of mice injected with P32 are highest with a diet low in fat and in protein, and are significantly decreased when the level of the fat, or of the protein, or both, are increased in the diet. Enrichment of the diets with inorganic phosphate seems to afford a moderate, but significant degree of protection against the injurious action of P32.
Modeling and simulation of the quasi-static compressive behavior of Al/Cu hybrid open-cell foams

The development and manufacturing of hybrid metal foams through nanocrystalline electrodeposited metal coatings has recently received increased attention for their promise for tailored performance. The performance of nano-reinforced foams has been demonstrated and assessed experimentally. However, methods to numerically study and simulate the behavior of metal hybrid foams are not well established. Further, clear explanation of the mechanisms behind their unique behavior is still lacking. Finite element method approaches considering both coating and base material damage are used in this study to investigate the failure mechanisms and mechanical performance of nanocrystalline hybrid open cell foams at micro and macro scales. The numerical models agree well with experimental results and have provide insight into the behavior and failure mechanisms of hybrid foams. It was found that the low ductility capacity of nanocrystalline coatings can cause early fracture of composite ligaments and localized damage at the macro scale and thus reduce the load carrying capacity. The numerical results also indicate that the performance of hybrid foams can be enhanced by improving the ductility capacity of the coating material.
Quenched point-to-point free energy for random walks in random potentials

We consider a random walk in a random potential on a square lattice of arbitrary dimension. The potential is a function of an ergodic environment and steps of the walk. The potential is subject to a moment assumption whose strictness is tied to the mixing of the environment, the best case being the i.i.d. environment. We prove that the infinite volume quenched point-to-point free energy exists and has a variational formula in terms of entropy. We establish regularity properties of the point-to-point free energy, and link it to the infinite volume point-to-line free energy and quenched large deviations of the walk. One corollary is a quenched large deviation principle for random walk in an ergodic random environment, with a continuous rate function.
Coping with power-limited transverse stochastic cooling systems

The authors present the formulas relevant to the behavior of (transverse) stochastic cooling systems which operate under the not uncommon condition that performance is limited by available output power. They contrast the operation of such systems with that of nonpower-limited ones. In particular, it is shown that, for power-limited systems, the two most effective improvements are the use of pickups/kickers which operate in both planes simultaneously and/or plunging of the cooling system electrodes. The results are applied to the proposed upgrade of the Fermilab debuncher ring. It is concluded that biplanarity and plunging offer comparable improvements in performance and, for power-limited situations, such as that which exists at the Fermilab debuncher ring, offer performance improvements greater than those resulting from an increase in operating frequency. >
Irredundant sequential machines via optimal logic synthesis

It is shown that optimal sequential logic synthesis can produce irredundant, fully testable finite-state machines. Synthesizing a sequential circuit from a state-transition-graph description involves the steps of state minimization, state assignment, and logic optimization. It is also shown that 100% testability can be ensured without the addition of extra logic and without constraints on the state assignment and logic optimization. There is no area/performance penalty associated with this approach. This technique can be used in conjunction with previous approaches to ensure that the synthesized machine is easily testable. Given a state-transition-graph specification, a logic-level automation that is fully testable for all single stuck-at faults in the combinational logic without access to the memory elements can be synthesized. These procedures represent an alternative to a scan-design methodology, without the latter's usual area and performance penalty. >
The median-voter hypothesis, income inequality, and income redistribution: an empirical test with the required data

The median-voter hypothesis has been central to an extensive literature on consequences of income redistribution. For example, it has been proposed that greater inequality is associated with lower growth, because of the greater redistribution that is sought by the median voter when income distribution is less equal. There have however been no proper tests of the median-voter hypothesis concerning redistribution, because of previous absence . of data on factor-income distribution that is, incomes before taxes and transfers across households, and thus on the gains by poorer households from redistribution. The study reported in this paper is based on the required data, with 79 observations drawn from household budget surveys from 24 democracies. The results strongly support the conclusion that countries with greater inequality of factor income redistribute more to the poor. This is so even when we control for the share of the elderly in the population and for pension transfers. The evidence that the median-voter hypothesis adequately describes the collec- tive-choice mechanism is however considerably weaker. Although middle-income groups . gain moreror lose less through redistribution in countries where initial factor income distribution is more unequal, this regularity is all but lost when, by excluding pensions, we
The public economics of self control

This paper analyzes self-control problems in intertemporal consumption of a sin good where current consumption imposes a negative externality on one’s future selves due to the existence of present-biased preferences. We introduce the negative externality dubbed ‘internality’, which is augmented by the cumulative distribution function of the sum of previous consumption. We show that the shot-run self with self-control problem over consumes the sin good compared to that of the long-run self without present-biased preferences. Further, we investigate the effectiveness of self-bargaining with the presence of an external control devise as possible punishment. The short-run self faces three possible options: do nothing, accept the long-run self’s offer, or reject the offer. In the latter case an external control devices is implemented. It is shown that successful self-bargaining depends on the efficiency of the control device.
Effects of plasma spatial profile on conversion efficiency of laser-produced plasma sources for EUV lithography

Extreme ultraviolet (EUV) lithography devices that use laser-produced plasma (LPP), discharge-produced plasma (DPP), and hybrid devices need to be optimized to achieve sufficient brightness with minimum debris generation to support the throughput requirements of high-volume manufacturing lithography exposure tools with a long lifetime. Source performance, debris mitigation, and reflector system are all critical to efficient EUV collection and component lifetime. Enhanced integrated models continue to be developed using the High Energy Interaction with General Heterogeneous Target Systems (HEIGHTS) computer package to simulate EUV photon emission, debris generation, and transport in both single and multiple laser beam interaction systems with various targets. A new Center for Materials under Extreme Environments (CMUXE) was recently established to benchmark HEIGHTS models for various EUV-related issues. The models being developed and enhanced were used to study the effect of plasma hydrodynamics evolution on the EUV radiation emission for planar and spherical geometry of a tin target and explain the higher conversion efficiency of a planar target in comparison to a spherical target. HEIGHTS can study multiple laser beams, various target geometries, and pre-pulses to optimize EUV photon production. Recent CMUXE and other experimental results are in good agreement with HEIGHTS simulation.
Relationship between dispersion metric and properties of PMMA/SWNT nanocomposites

Abstract Particle spatial dispersion is a crucial characteristic of polymer composite materials and this property is recognized as especially important in nanocomposite materials due to the general tendency of nanoparticles to aggregate under processing conditions. We introduce dispersion metrics along with a specified dispersion scale over which material homogeneity is measured and consider how the dispersion metrics correlate quantitatively with the variation of basic nanocomposite properties. We then address the general problem of quantifying nanoparticle spatial dispersion in model nanocomposites of single-walled carbon nanotubes (SWNTs) dispersed in poly(methyl methacrylate) (PMMA) at a fixed SWNT concentration of 0.5% using a ‘coagulation’ fabrication method. Two methods are utilized to measure dispersion, UV–vis spectroscopy and optical confocal microscopy. Quantitative spatial dispersion levels were obtained through image analysis to obtain a ‘relative dispersion index’ (RDI) representing the uniformity of the dispersion of SWNTs in the samples and through absorbance. We find that the storage modulus, electrical conductivity, and flammability property of the nanocomposites correlate well with the RDI. For the nanocomposites containing the same amount of SWNTs, the relationships between the quantified dispersion levels and physical properties show about four orders of magnitude variation in storage modulus, almost eight orders of magnitude variation in electric conductivity, and about 70% reduction in peak mass loss rate at the highest dispersion level used in this study. The observation of such a profound effect of SWNT dispersion indicates the need for objective dispersion metrics for correlating and understanding how the properties of nanocomposites are determined by the concentration, shape and size of the nanotubes.
Kinematic precision of gear trains

Kinematic precision is affected by errors which are the result of either intentional adjustments or accidental defects in manufacturing and assembly of gear trains. A method for the determination of kinematic precision of gear trains is described. The method is based on the exact kinematic relations for the contact point motions of the gear tooth surfaces under the influence of errors. An approximate method is also explained. Example applications of the general approximate methods are demonstrated for gear trains consisting of involute (spur and helical) gears, circular arc (Wildhaber-Novikov) gears, and spiral bevel gears. Gear noise measurements from a helicopter transmission are presented and discussed with relation to the kinematic precision theory.
Modelling Quasicrystals at Positive Temperature

We consider a two-dimensional lattice model of equilibrium statistical mechanics, using nearest neighbor interactions based on the matching conditions for an aperiodic set of 16 Wang tiles. This model has uncountably many ground state configurations, all of which are nonperiodic. The question addressed in this paper is whether nonperiodicity persists at low but positive temperature. We present arguments, mostly numerical, that this is indeed the case. In particular, we define an appropriate order parameter, prove that it is identically zero at high temperatures, and show by Monte Carlo simulation that it is nonzero at low temperatures.
Changing threat perceptions and the efficient provisioning of international security

This paper proposes a mechanism for structuring international institutions to efficiently provision global security against the threat of a rogue nation. The effects of security effort by an alliance member are assumed to be non-rival and non-excludable for other members. Specifically, this effort has both positive and negative effects, as security measures prevent attacks by the rogue nation, but also involves loss of commercial and diplomatic benefits. Further, the alliance members are assumed to have heterogeneous tastes regarding the desired security level. The allies act strategically vis-a-vis one another with regard to security provision, and the alliance a whole acts strategically with respect to the rogue nation, which strategizes in turn. Importantly, this paper investigates how the evolution of public opinion, in the respective countries facing the rogue nation's threat, impacts the proposed mechanism.
Nonclassical Kinetics in Constrained Geometries: Initial Distribution Effects

We present a detailed study of the effects of the initial distribution on the kinetic evolution of the irreversible reaction A+B→0 in one dimension. Our analytic as well as numerical work is based on a reaction–diffusion model of this reaction. We focus on the role of initial density fluctuations in the creation of the macroscopic patterns that lead to the well-known kinetic anomalies in this system. In particular, we discuss the role of the long wavelength components of the initial fluctuations in determining the long-time behavior of the system. We note that the frequently studied random initial distribution is but one of a variety of possible distributions leading to interesting anomalous behavior. Our discussion includes an initial distribution with correlated A-B pairs and one in which the initial distribution forms a fractal pattern. The former is an example of a distribution whose long wavelength components are suppressed, while the latter exemplifies one whose long wavelength components are enhanced, relative to those of the random distribution.
The Neural Basis of Addiction: A Pathology of Motivation and Choice

Objective: A primary behavioral pathology in drug addiction is the overpowering motivational strength and decreased ability to control the desire to obtain drugs. In this review the authors explore how advances in neurobiology are approaching an understanding of the cellular and circuitry underpinnings of addiction, and they describe the novel pharmacotherapeutic targets emerging from this understanding. Method: Findings from neuroimaging of addicts are integrated with cellular studies in animal models of drug seeking.
Robust maintenance policies for Markovian systems under model uncertainty

Asset management systems help public works agencies decide when and how to maintain and rehabilitate infrastructure facilities in a cost-effective manner. Many sources of error, some difficult to quantify, can limit the ability of asset management systems to accurately predict how built systems will deteriorate. This article introduces the use of robust optimization to deal with epistemic uncertainty. The Hurwicz criterion is employed to ensure management policies are never "too conservative." An efficient solution algorithm is developed to solve robust counterparts of the asset management problem. A case study demonstrates how the consideration of uncertainty alters optimal management policies and shows how the proposed approach may reduce maintenance and rehabilitation (M&R) expenditures.
Active Intermediation in Overlapping Generations Economies with Production and Unsecured Debt

It is well known that the first welfare theorem can fail for overlapping generations economies with private production and unsecured debt. This paper demonstrates that the reason for this failure is that intermediation is modeled as a purely passive coordination activity implemented by a Walrasian Auctioneer. When intermediation is modeled instead as a contestable activity carried out by a corporate intermediary owned by consumer-shareholders and operated in their interest, every equilibrium is Pareto efficient. In broader terms, these findings caution that the inefficiency observed in standard modelings of overlapping generations economies may not be the reflection of an intrinsic market failure. Rather, the observed inefficiency could instead be due to a fundamental incompleteness in the model specification â€” the presumed inability of private agents to exploit the earnings opportunities associated with incurring and forever rolling over debt.
Gaussian beam and physical optics iteration technique for wideband beam waveguide feed design

A novel approach is demonstrated which involves iterating Gaussian beam and beam waveguide (BWG) parameters to obtain a wideband BWG feed. The result is further improved by making a comparison with the physical-optics result and repeating the iteration. The basic goal was to design a BWG feed system with good performance from 2 to 32 GHz, utilizing mirror sizes of 20 lambda at the low frequency. The BWG antenna performance (e.g. gain, efficiency, noise temperature) at S, X, and Ka-bands is presented. It is noted that higher-gain horns are needed for higher frequencies. >
Applications of the classical umbral calculus

We describe applications of the classical umbral calculus to bilinear generating functions for polynomial sequences, identities for Bernoulli and related numbers, and Kummer congruences.
GENERIC VANISHING THEORY VIA MIXED HODGE MODULES

We extend most of the results of generic vanishing theory to bundles of holomorphic forms and rank-one local systems, and more generally to certain coherent sheaves of Hodge-theoretic origin associated with irregular varieties. Our main tools are Saito’s mixed Hodge modules, the Fourier‐Mukai transform for D-modules on abelian varieties introduced by Laumon and Rothstein, and Simpson’s harmonic theory for flat bundles. In the process, we also discover two natural categories of perverse coherent sheaves.
Laws versus Contracts: Shareholder Protections and Ownership Concentration in Brazil, 1890–1950

This article examines some of the institutional conditions that facilitated the development of equity markets in Brazil. A critical factor was the addition to corporate bylaws of protections for investors, which enabled relatively large corporations in Brazil to attract investors in large numbers. By availing themselves of this strategy, the firms generated a relatively low concentration of ownership before 1910. Archival evidence, such as company statutes and shareholder lists, reveals that the addition of voting rights to their bylaws, particularly maximum-vote provisions and graduated voting scales (which stipulated that less-than-proportional votes increase in parallel with shareholdings), allowed many Brazilian corporations to balance the relative voting power of their small and large investors. In companies that made such arrangements, the concentration of ownership and control was sharply lower than in the average company. Judging by the Brazilian companies examined for this article, it also appears that the concentration of control was significantly lower before 1910 than it is today.
Accurate rotor position detection and sensorless control of SRM for super-high speed operation

Based on the general nonlinear magnetizing model (GNMM) from our previous research work, an improved method of detecting rotor position for sensorless control of SRMs in super-high speed operation has been developed. With minimum input data, the approximated GNMM is obtained and the rotor speed estimated. Then the rotor position is detected by the motion equation. To remove rotor position error, the proposed scheme updates the reference at critical points using the flux observation. Further, the GNMM is adaptively tuned based on the updated information. The improved rotor position detection method has been implemented by fully exploring the computation power of the modern DSP. Laboratory verification on different types of SRMs with sensorless control up to 20000 rpm is accomplished.
A semi-classical limit of the gauge/string correspondence

Abstract A world-sheet sigma model approach is applied to string theories dual to four-dimensional gauge theories, and semi-classical soliton solutions representing highly excited string states are identified which correspond to gauge theory operators with relatively small anomalous dimensions. The simplest class of such states are strings on the leading Regge trajectory, with large spin in AdS 5 . These correspond to operators with many covariant derivatives, whose anomalous dimension grows logarithmically with the space–time spin. In the gauge theory, the logarithmic scaling violations are similar to those found in perturbation theory. Other examples of highly excited string states are also considered.
A methodology for measuring engineering knowledge worker productivity

In contrast with hourly manufacturing and service workers, the productivity of salaried knowledge workers such as engineers can be difficult to measure. In particular, hourly workers may practice p...
Performance bounds on compressed sensing with Poisson noise

This paper describes performance bounds for compressed sensing in the presence of Poisson noise when the underlying signal, a vector of Poisson intensities, is sparse or compressible (admits a sparse approximation). The signal-independent and bounded noise models used in the literature to analyze the performance of compressed sensing do not accurately model the effects of Poisson noise. However, Poisson noise is an appropriate noise model for a variety of applications, including low-light imaging, where sensing hardware is large or expensive, and limiting the number of measurements collected is important. In this paper, we describe how a feasible positivity-preserving sensing matrix can be constructed, and then analyze the performance of a compressed sensing reconstruction approach for Poisson data that minimizes an objective function consisting of a negative Poisson log likelihood term and a penalty term which could be used as a measure of signal sparsity.
Triptycene-Based, Carboxylate-Bridged Biomimetic Diiron(II) Complexes

A triptycene-based bis(benzimidazole) ester ligand, L3, was designed to enhance the electron donating ability of the heterocyclic nitrogen atoms relative to those of the first generation bis(benzoxazole) analogs, L1 and L2. A convergent synthesis of L3 was designed and executed. Three-component titration experiments using UV-visible spectroscopy revealed that the desired diiron(II) complex could be obtained with a 1:2:1 ratio of L3:Fe(OTf)2(MeCN)2:external carboxylate reactants. X-ray crystallographic studies of two diiron complexes derived in this manner from L3 revealed their formulas to be [Fe2L3(μ-OH)(μ-O2CR)(OTf)2], where R = 2,6-bis(p-tolyl)benzoate (7) or triphenylacetate (8). The structures are similar to that of a diiron complex derived from L1, [Fe2L1(μ-OH)(μ-O2CArTol)(OTf)2] (9) with a notable difference being that, in 7 and 8, the geometry at iron more closely resembles square-pyramidal than trigonal-bipyramidal. Mossbauer spectroscopic analyses of 7 and 8 indicate the presence of high-spin diiron(II) cores. These results demonstrate the importance of substituting benzimidazole for benzoxazole for assembling biomimetic diiron complexes with syn disposition of two N-donor ligands, as found in O2-activating carboxylate-bridged diiron centers in biology.
Applications of Event-by-Event Fission Modeling with FREYA

The recently developed codeFREYA (Fission Reaction Event Yield Algo- rithm) generates large samples of complete fission events, consisting of two receding product nuclei as well as a number of neutrons and photons, all with complete kinematic information. Thus it is possible to calculate arbitrary correlation observables whose behav- ior may provide unique insight into the fission process. We first discuss the present status ofFREYA, which has now been extended to include spontaneous fission. Concentrating on 239 Pu(n th,f), 240 Pu(sf) and 252 Cf(sf), we discuss the neutron multiplicity correlations, the dependence of the neutron energy spectrum on the neutron multiplicity, and the relation- ship between the fragment kinetic energy and the number of neutrons and their energies. We also suggest novel fission observables that could be measured with modern detectors.
T cell anergy

T cell anergy is a tolerance mechanism in which the lymphocyte is intrinsically functionally inactivated following an antigen encounter, but remains alive for an extended period of time in a hyporesponsive state. Models of T cell anergy affecting both CD4(+) and CD8(+) cells fall into two broad categories. One, clonal anergy, is principally a growth arrest state, whereas the other, adaptive tolerance or in vivo anergy, represents a more generalized inhibition of proliferation and effector functions. The former arises from incomplete T cell activation, is mostly observed in previously activated T cells, is maintained by a block in the Ras/MAP kinase pathway, can be reversed by IL-2 or anti-OX40 signaling, and usually does not result in the inhibition of effector functions. The latter is most often initiated in naive T cells in vivo by stimulation in an environment deficient in costimulation or high in coinhibition. Adaptive tolerance can be induced in the thymus or in the periphery. The cells proliferate and differentiate to varying degrees and then downregulate both functions in the face of persistent antigen. The state involves an early block in tyrosine kinase activation, which predominantly inhibits calcium mobilization, and an independent mechanism that blocks signaling through the IL-2 receptor. Adaptive tolerance reverses in the absence of antigen. Aspects of both of the anergic states are found in regulatory T cells, possibly preventing them from dominating initial immune responses to foreign antigens and shutting down such responses prematurely.
Source Detection by Model-Order Selection in State Space

This paper evaluates the performance of a source detection procedure that uses Akaike's minimum Final Prediction Error criterion. The procedure selects the order of a state-space model of the array signal, which, in turn, forms the basis of Hinfin optimal single-snapshot direction finding. The authors analyze source detection as a sequential binary hypothesis test and estimate its effective "false alarm rate." The paper also presents detection results from synthetic data generated by the Sonar Simulation Toolset, which corroborate the authors' findings.
High Resolution, Long Term Characterization of Bacterial Motility Using Optical Tweezers

We present a single-cell motility assay1, which allows the quantification of bacterial swimming in a well-controlled environment, for durations of up to an hour and with a temporal resolution greater than the flagellar rotation rates of ∼100 Hz. The assay is based on an instrument combining optical tweezers, light and fluorescence microscopy, and a microfluidic chamber. Using this device we characterized the long-term statistics of the run-tumble time series in individual Escherichia coli cells. We also quantified higher-order features of bacterial swimming, such as changes in velocity and reversals of swimming direction.[1] Min, T.L., Mears, P.J., Chubiz, L.M., Rao, C.V., Golding, I. & Chemla, Y.R. (2009) High-resolution, long-term characterization of bacterial motility using optical tweezers. Nature Methods (in press)View Large Image | View Hi-Res Image | Download PowerPoint Slide
Constrained dynamics of universally coupled massive spin 2-spin 0 gravities

The 2-parameter family of massive variants of Einsteins gravity (on a Minkowski background) found by Ogievetsky and Polubarinov by excluding lower spins can also be derived using universal coupling. A Dirac-Bergmann constrained dynamics analysis seems not to have been presented for these theories, the Freund-Maheshwari-Schonberg special case, or any other massive gravity beyond the linear level treated by Marzban, Whiting and van Dam. Here the Dirac-Bergmann apparatus is applied to these theories. A few remarks are made on the question of positive energy. Being bimetric, massive gravities have a causality puzzle, but it appears soluble by the introduction and judicious use of gauge freedom.
Regiospecific bromination of 3-methylindoles with N-bromosuccinimide

Abstract The regiospecific bromination of various substituted 3-methylindoles at either C(2) or the C(3) alkyl moiety was accomplished via an electrophilic or free radical bromination process to provide intermediates for indole alkaloid total synthesis. The regiospecificity of the bromination could be controlled by variation of both the substituent and the N(1) protecting group on the indole ring.
Electrical fiber brushes-theory and observations

The performance limits of electrical fiber brushes are assessed by means of an expanded, refined theory. Measurements back to 1979 are in accord with the theory, including 1993 measurements on a set of 64 fiber brushes in a homopolar motor at the U.S. Navy Annapolis Laboratory, At /spl nu/=7.6 m/s velocity and j=1 MA/m/sup 2/ the electric loss was 0.026 W/A, and after a 20 h test the brushes showed no detectable wear. On the other end of the scale, electrical brushes are being developed for a maglev train system (American Maglev Tech of Florida, Inc.) to operate up to 150 m/s. According to the theory, this will be possible in the open atmosphere with dimensionless wear rates smaller than 10/sup -8/ at current densities up to a few MA/m/sup 2/. At speeds to 300 m/s, projected losses may range up to 4.3 W/A at flash temperatures at and below 100/spl deg/C. The newest fiber brushes preserve the high contact spot density at the ends of individually flexible fibers, independent of amount of wear. Correspondingly, with 10 cm long brushes, for example, the projected maglev brushes should last at least for a New York-Los Angeles return trip. Also, on account of the changed method of construction, manufacturing costs have decreased by more than a factor of ten in the past two years. Prospects are that with industrial manufacturing techniques the cost of fiber brushes, based on ampere hours conducted, will become easily competitive with monolithic graphite brushes. Pending further practical experience, it is therefore expected that: (1) metal fiber brushes will expand the range of sliding brush applicability and (2) ultimately displace graphite brushes for most of their present applications.
Treatment-Resistant Hypertension and the Incidence of Cardiovascular Disease and End-Stage Renal Disease Results From the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT)

Apparent treatment-resistant hypertension (aTRH) is defined as uncontrolled hypertension despite the use of ≥3 antihypertensive medication classes or controlled hypertension while treated with ≥4 antihypertensive medication classes. Although a high prevalence of aTRH has been reported, few data are available on its association with cardiovascular and renal outcomes. We analyzed data on 14 684 Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) participants to determine the association between aTRH (n=1870) with coronary heart disease, stroke, all-cause mortality, heart failure, peripheral artery disease, and end-stage renal disease. We defined aTRH as blood pressure not at goal (systolic/diastolic blood pressure ≥140/90 mm Hg) while taking ≥3 classes of antihypertensive medication or taking ≥4 classes of antihypertensive medication with blood pressure at goal during the year 2 ALLHAT study visit (1996-2000). Use of a diuretic was not required to meet the definition of aTRH. Follow-up occurred through 2002. The multivariable adjusted hazard ratios (95% confidence intervals) comparing participants with versus without aTRH were as follows: coronary heart disease (1.44 [1.18-1.76]), stroke (1.57 [1.18-2.08]), all-cause mortality (1.30 [1.11-1.52]), heart failure (1.88 [1.52-2.34]), peripheral artery disease (1.23 [0.85-1.79]), and end-stage renal disease (1.95 [1.11-3.41]). aTRH was also associated with the pooled outcomes of combined coronary heart disease (hazard ratio, 1.47; 95% confidence interval, 1.26-1.71) and combined cardiovascular disease (hazard ratio, 1.46; 95% confidence interval, 1.29-1.64). These results demonstrate that aTRH increases the risk for cardiovascular disease and end-stage renal disease. Studies are needed to identify approaches to prevent aTRH and reduce risk for adverse outcomes among individuals with aTRH.
Brand Extension as Informational Leverage

The marketing literature refers to the concept of brand capital and provides empirical evidence that firms with a large stock of well-established brands have an advantage in introducing new products. This paper develops a theory of brand extension as a mechanism for informational leverage in which a firm leverages off a good's reputation in one market to alleviate the problem of informational asymmetry encountered in other markets. It is shown that brand extension helps a multi-product monopolist introduce a new experience good with less price distortion. Thus, the paper provides a theoretical foundation for the concept of brand capital.