cssi/SciSciGPT-SciSciNet huggingface dataset:
CO-MOVEMENTS IN INTERNATIONAL EQUITY MARKETS

We examine the co-movements of equity returns in four major international markets by characterizing the time-varying cross-country covariances and correlations. Using a generalized positive definite multivariate GARCH model, we find that the Japanese and U.S. stock markets have significant transitory covariance, but zero permanent covariance. The other pairs of markets examined display significant permanent and transitory covariance. We also find that, while conditional correlations between returns are generally small, they change considerably over time. An event analysis suggests that basing diversification strategies on these conditional correlations is potentially beneficial.
Potential-pH behavior of plutonium solutions containing hydrous oxides

Abstract The oxidation-reduction potential decreases linearly with increasing pH in solutions that contain both tetravalent and hexavalent plutonium hydrous oxides. An equation predicting the potential is compared to an equation describing some potentials found experimentally by Rai. The corresponding slopes and intercepts of the two equations differ by only a few per cent.
Palladium-catalyzed cyclic acylmetalation of allylic electrophiles as a route to cyclopentenone derivatives

Abstract Treatment of allylic electrophiles containing an additional alkene moiety in a suitable position with CO, NEt 3 , MeOH, and a catalytic amount of a Pd catalyst, e.g., Cl 2 Pd(PPh 3 ) 2 , can induce cyclic acylmetallation followed by carbonylative esterification to produce α-methoxycarbonylmethyl cyclopentenones.
Radiative and Dynamical Forcing of the Surface and Atmospheric Temperature Anomalies Associated with the Northern Annular Mode

AbstractOn the basis of the total energy balance within an atmosphere–surface column, an attribution analysis is conducted for the Northern Hemisphere (NH) atmospheric and surface temperature response to the northern annular mode (NAM) in boreal winter. The local temperature anomaly in the European Centre for Medium-Range Weather Forecasts (ECMWF) Interim Re-Analysis (ERA-Interim) is decomposed into partial temperature anomalies because of changes in atmospheric dynamics, water vapor, clouds, ozone, surface albedo, and surface dynamics with the coupled atmosphere–surface climate feedback–response analysis method (CFRAM). Large-scale ascent/descent as part of the NAM-related mean meridional circulation anomaly adiabatically drives the main portion of the observed zonally averaged atmospheric temperature response, particularly the tropospheric cooling/warming over northern extratropics. Contributions from diabatic processes are generally small but could be locally important, especially at lower latitudes wh...
Algebraic cycles of a fixed degree

In this paper, the homotopy groups of Chow variety $C_{p,d}(P^n)$ of effective $p$-cycles of degree $d$ is proved to be stable in the sense that $p$ or $n$ increases. We also obtain a negative answer to a question by Lawson and Michelsohn on homotopy groups for the space of degree two cycles.
Thermal Stability of MOCVD and HVPE GaN Layers in H2, HCl, NH3 and N2

This work represents a complete study of GaN annealed in H2, HCl, NH3 and N2. The GaN thermal behavior was evaluated by comparison of MOCVD and HVPE samples. The MOCVD films were found to obey a dissociative sublimation mechanism with only gaseous species forming, while the HVPE films reacted with ambient gases to form condensed Ga in addition to the gaseous species. Differences in crystal quality for MOCVD and HVPE samples resulting from the different growth mechanisms account for the observed difference. This analysis of the thermal stability of GaN is extended to include how polarity affects the thermal behavior of GaN during growth and annealing of MOCVD and HVPE films.
Effect of epinephrine infusion and adrenergic blockade on glucose oxidation in conscious dogs

The effect of combined alpha- and beta-adrenergic blockade, and the effect of epinephrine infusion, on the rate of glucose oxidation has been tested in conscious dogs. The dogs were prepared seven to ten days before the experiment with chronic catheters and tracheostomy. Glucose oxidation was measured by means of the primed-constant infusion of U-14C-glucose and indirect calorimetry. Six experimental groups were tested. In all groups, insulin and glucagon concentrations were held constant throughout by the inhibition of their secretion with somatostatin and intraportal replacement at basal rates. All experiments consisted of two two-hour periods. In half of the experiments, combined alpha- and beta-adrenergic blockade was administered in the second period, and in the other experiments, epinephrine was infused in the second period. The adrenergic blockade or epinephrine infusion (E) was performed in three different groups. In one, free fatty acid (FFA) levels were allowed to change spontaneously in response to blockade or E; in a second group, liposyn and heparin were infused throughout periods 1 and 2 in order to maintain FFA levels at high, constant levels; and in a third group, FFA levels were maintained at a constant low level in periods 1 and 2 by means of an infusion of nicotinic acid. In all cases tested, epinephrine infusion caused an increase in the rate of glucose oxidation. Adrenergic blockade also caused an increase in glucose oxidation when FFA levels were allowed to spontaneously fall; but when FFA levels were held constant (either high or low), there was no effect on glucose oxidation. When changes in plasma kinetics of glucose were accounted for, no significant change in the percentage of glucose uptake oxidized was recorded in any group. We conclude that neither sympathetic nervous system activity nor epinephrine infusion causes a decrement in the ability to oxidize a given amount of glucose.
Methods and strategies of peptide ligation.

This review focuses on the concept, methods, and strategies of orthogonal peptide ligation. It updates our previous review in 1999 on the same subject matter in Biopolymers (Peptide Science, 1999, Vol. 51, p. 311). Orthogonal peptide ligation is an amino terminal specific method to couple chemically unprotected peptides or proteins derived from synthetic or biosynthetic sources. Unlike conventional chemical methods, peptide ligation methods do not require coupling reagents or protection schemes, but are achieved through a variable chemoselective capture step and then an invariable intramolecular acyl transfer reaction. It is also a convergent method with the fewest steps. More than a dozen orthogonal ligation methods have been developed based on captures by either imine or thioester chemistries to afford native and unusual amino acids at ligation sites of linear, branched, or cyclic peptides. The ligation strategies for multiple segments including sequential and tandem ligations are also discussed.
A Reciprocity Relation for WP-Bailey Pairs

We derive a new general transformation for WP-Bailey pairs by considering a certain limiting case of a WP-Bailey chain previously found by the authors, and examine several consequences of this new transformation. These consequences include new summation formulae involving WP-Bailey pairs. Other consequences include new proofs of some classical identities due to Jacobi, Ramanujan and others, and indeed extend these identities to identities involving particular specializations of arbitrary WP-Bailey pairs.
Lattices from Codes for Harnessing Interference: An Overview and Generalizations

In this paper, using compute-and-forward as an example, we provide an overview of constructions of lattices from codes that possess the right algebraic structures for harnessing interference. This includes Construction A, Construction D, and Construction $\pi_A$ (previously called product construction) recently proposed by the authors. We then discuss two generalizations where the first one is a general construction of lattices named Construction $\pi_D$ subsuming the above three constructions as special cases and the second one is to go beyond principal ideal domains and build lattices over algebraic integers.
Electron and hole effective masses for two-dimensional transport in strained-layer superlattices

Abstract The first theoretical study of the electron and hole effective masses along the layers of (100) strained-layer superlattices grown from direct and indirect gap materials is presented. The results indicate that the large layer strains in these structures can produce electron masses associated with the X valleys and hole masses which are significantly reduced from bulk values. The electron values are typically ∼ 0.2 m e and the hole values are typically e . These results have important implications for the low field transport properties of strained-layer systems.
Structure Theorem for ( d , g , h )-Maps

The (3x + 1)-Map, T, acts on the set, Π, of positive integers not divisible by 2 or 3. It is defined by \(T(x) = \frac{{3x + 1}} {{2^k }}\), where k is the largest integer for which T (x) is an integer. The (3x + 1)-Conjecture asks if for every x e Π there exists an integer, n, such that Tn (x) = 1. The Statistical (3x + 1)-Conjecture asks the same question, except for a subset of Π of density 1. The Structure Theorem proven in [S] shows that infinity is in a sense a repelling point, giving some reasons to expect that the (3x + 1)-Conjecture may be true. In this paper, we present the analogous theorem for some generalizations of the (3x + 1)-Map, and expand on the consequences derived in [S]. The generalizations we consider are determined by positive coprime integers, d and g, with g > d ≥ 2, and a periodic function, h (x). The map T is defined by the formula \(T(x) = \frac{{gx + h(gx)}} {{d^k }}\), where k is again the largest integer for which T (x) is an integer. We prove an analogous Structure Theorem for (d, g, h)-Maps, and that the probability distribution corresponding to the density converges to the Wiener measure with the drift \(\log g - \frac{d} {{d - 1}}\) and positive diffusion constant. This shows that it is natural to expect that typical trajectories return to the origin if \(\log g - \frac{d} {{d - 1}}\log d < 0\) and escape to infinity otherwise.
On Invariants of Hirzebruch and Cheeger{Gromov

We prove that, if M is a compact oriented manifold of dimension 4k +3 , where k> 0, such that 1(M) is not torsion-free, then there are innitely many manifolds that are homotopic equivalent to M but not homeomorphic to it. To show the innite size of the structure set of M ,w e construct a secondary invariant (2) : S(M ) ! R that coincides with the {invariant of Cheeger{Gromov. In particular, our result shows that the {invariant is not a homotopy invariant for the manifolds in question. AMS Classication numbers Primary: 57R67 Secondary: 46L80, 58G10
Photosensitive thin film materials and devices

Abstract Planarization of photosensitive device technology promises to expand the application options for this type of material. In this paper, we report on the production of highly photosensitive thin films, without the use of post-deposition processing, which promise compatibility and integrability with III–V and Si processing. We investigate the optical bleaching of structural defects, responsible for the photosensitive response exhibited by our materials, and assess defect thermal stability. It is seen that films deposited at a substrate temperature of 600°C demonstrate defect stability up to temperatures of approximately 550°C, whereas films deposited on ambient temperature substrates show evidence of structural relaxation at temperatures above 250°C. Such relaxation in the ambient temperature samples is accompanied by changes in the photosensitive response of the material. Finally, we demonstrate the operation of waveguide-based integrated photonic devices within our films.
Comments on the space-symmetry interpretation of the gauge orientations of the instanton in the higgs phase

Abstract We comment on introduction of the instanton collective coordinates in the theories with the spontaneously broken gauge symmetry. In distinction with the pure gauge theories some gauge-invariant quantities acquire explicit dependence on the collective coordinates associated with the gauge field orientation in the gauge group, which looks rather paradoxically. This dependence, however, is absolutely necessary for preserving the Lorentz invariance of the instanton-induced amplitudes.
Application of structural-mechanics methods to the design of large tandem-mirror fusion devices (MFTF-B)

The Mirror Fusion Test Facility (MFTF-B) at Lawrence Livermore National Laboratory requires state-of-the-art structural-mechanics methods to deal with access constraints for plasma heating and diagnostics, alignment requirements, and load complexity and variety. Large interactive structures required an integrated analytical approach to achieve a reasonable level of overall system optimization. The Tandem Magnet Generator (TMG) creates a magnet configuration for the EFFI calculation of electromagnetic-field forces that, coupled with other loads, form the input loading to magnet and vessel finite-element models. The analytical results provide the data base for detailed design of magnet, vessel, foundation, and interaction effects.
THE INITIAL VALUE PROBLEM IN NUMERICAL RELATIVITY

The conformal method for constructing initial data for Einstein's equations is presented in both the Hamiltonian and Lagrangian picture (extrinsic curvature decomposition and conformal thin sandwich formalism, respectively), and advantages due to the recent introduction of a weight-function in the extrinsic curvature decomposition are discussed. I then describe recent progress in numerical techniques to solve the resulting elliptic equations, and explore innovative approaches toward the construction of astrophysically realistic initial data for binary black hole simulations.
Comparative Analysis of Super-Kamiokande and SNO Solar-Neutrino Data and the Photospheric Magnetic Field

We carry out a comparative analysis of Super-Kamiokande, SNO, and photospheric magnetic-field data for the interval in which these datasets overlap. This proves to be the interval of operation of the D2O phase of the SNO experiment. Concerning solar-rotational modulation, we find that the magnetic-field power spectrum shows the strongest peaks at the second and sixth harmonics of the solar synodic rotation frequency [i.e., at 3νrot and 7νrot]. We find that the restricted Super-Kamiokande dataset has a strong modulation at the second harmonic, as we found to be the case for the complete Super-Kamiokande dataset. The SNO D2O dataset exhibits weak modulation at that frequency, but shows strong modulation in the band corresponding to the sixth harmonic (too high a frequency to be detectable in the Super-Kamiokande dataset, which is available only in five-day bins, whereas SNO data is available in one-day bins). We estimate the significance level of the correspondence of the Super-Kamiokande second-harmonic peak with the corresponding magnetic-field peak to be 0.0004, and the significance level of the correspondence of the SNO D2O sixth-harmonic peak with the corresponding magnetic-field peak to be 0.009. By estimating the amplitude of the modulation of the solar-neutrino flux at the second harmonic from the restricted Super-Kamiokande dataset, we find that the weak power at that frequency in the SNO D2O power spectrum is not particularly surprising. We also examine power spectra in the neighborhood of 9.43 year−1, which is the frequency of a particularly strong modulation in the entire Super-Kamiokande dataset. There is no peak at this frequency in the power spectrum formed from the restricted Super-Kamiokande dataset. It is therefore not surprising that we find (in agreement with the recent analysis by the SNO collaboration) that this peak does not show up in the SNO D2O dataset either.
Quantum degenerate Bose-Fermi mixtures on one-dimensional optical lattices

We study numerically and analytically the phases of a mixture of ultracold bosons and spin-polarized fermions in a one-dimensional lattice. In particular, along a symmetry plane in the parameter space, we obtain the exact boundary of the boson-demixing transition from the Bethe ansatz solution of the standard Hubbard model. For a region of parameter space, we prove the existence of boson-fermion mixed phase at all densities. This phase is a two-component Luttinger liquid for weak couplings or for incommensurate total density, otherwise it has a charge gap but retains a gapless mode of mixture composition fluctuations. We show that the static density correlations in these two regimes are markedly different.
A Q-Ising model application for linear-time image segmentation

A computational method is presented which efficiently segments digital grayscale images by directly applying the Q-state Ising (or Potts) model. Since the Potts model was first proposed in 1952, physicists have studied lattice models to gain deep insights into magnetism and other disordered systems. For some time, researchers have realized that digital images may be modeled in much the same way as these physical systems (i.e., as a square lattice of numerical values). A major drawback in using Potts model methods for image segmentation is that, with conventional methods, it processes in exponential time. Advances have been made via certain approximations to reduce the segmentation process to power-law time. However, in many applications (such as for sonar imagery), real-time processing requires much greater efficiency. This article contains a description of an energy minimization technique that applies four Potts (Q-Ising) models directly to the image and processes in linear time. The result is analogous to partitioning the system into regions of four classes of magnetism. This direct Potts segmentation technique is demonstrated on photographic, medical, and acoustic images.
Galactic center research: manifestations of the central black hole

This review summarizes a few of the frontiers of Galactic center research that are currently the focus of considerable activity and attention. It is aimed at providing a necessarily incomplete sketch of some of the timely work being done on phenomena taking place in, or originating in, the central few parsecs of the Galaxy, with particular attention to topics related to the Galactic black hole (GBH). We have chosen to expand on the following exciting topics: 1) the characterization and the implications for the variability of emission from the GBH, 2) the strong evidence for a powerful X-ray flare in the Galactic center within the past few hundred years, and the likelihood that the GBH is implicated in that event, 3) the prospects for detecting the “shadow” of the GBH, 4) an overview of the current state of research on the central S-star cluster, and what has been learned from the stellar orbits within that cluster, and 5) the current hypotheses for the origin of the G2 dust cloud that is projected to make a close passage by the GBH in 2013.
The relationship between the ITCZ and the Southern Hemispheric eddy‐driven jet

We study the effect of a thermal forcing confined to the midlatitudes of one hemisphere on the eddy-driven jet in the opposite hemisphere. We demonstrate the existence of an “interhemispheric teleconnection,” whereby warming (cooling) the Northern Hemisphere causes both the intertropical convergence zone (ITCZ) and the Southern Hemispheric midlatitude jet to shift northward (southward). The interhemispheric teleconnection is effected by a change in the asymmetry of the Hadley cells: as the ITCZ shifts away from the Equator, the cross-equatorial Hadley cell intensifies, fluxing more momentum toward the subtropics and sustaining a stronger subtropical jet. Changes in subtropical jet strength, in turn, alter the propagation of extratropical waves into the tropics, affecting eddy momentum fluxes and the eddy-driven westerlies. The relevance of this mechanism is demonstrated in the context of future climate change simulations, where shifts of the ITCZ are significantly related to shifts of the Southern Hemispheric eddy-driven jet in austral winter. The possible relevance of the proposed mechanism to paleoclimates is discussed, particularly with regard to theories of ice age terminations.
On the use of Godhavn H-component as an indicator of the interplanetary sector polarity

An objective method of inferring the polarity of the interplanetary magnetic field using the H-component at Godhavn is presented. The objectively inferred polarities are compared with a subjective index inferred earlier. It is concluded that no significant difference exists between the two methods. The inferred polarities derived from Godhavn H is biased by the (slp) sub q signature in the sense that during summer prolonged intervals of geomagnetic calm will result in inferred Away polarity regardless of the actual sector polarity. This bias does not significantly alter the large scale structure of the inferred sector structure.
Ruthenium(III) chloride catalyzed acylation of alcohols, phenols, thiols, and amines

Ruthenium(III) chloride catalyzes the acylation of a variety of phenols, alcohols, thiols, and amines under mild conditions. Some of the major advantages of this method are high yields, short reaction times, ease of operation, and compatibility with other protecting groups.
Oxidizer Size Distribution Effects on Propellant Combustion

The effect of the oxidizer size and size distribution on the pressure and temperature sensitivity for a nonaluminized composite solid propellant was investigated using a new mathematical model called the Petite Ensemble Model. Calculations were made using the new model, taking into account the oxidizer size and size distribution in determining the burning rates, rate exponents, and temperature sensitivities. Results were obtained for both unimodal and bimodal propellants with oxidizer particle sizes ranging from ultrafine (0.7 /*) to coarse (400 /*). For unimodal propellants, it was determined that the burning rate was higher for the smaller oxidizer sizes, as would be expected. Moreover, the rate exponent was larger for the small and large oxidizer particles with a minimum exponent obtained for some intermediate oxidizer diameter. Temperature sensitivity was found to be higher for propellants with larger oxidizer particles. However, it was found that the temperature sensitivity was constant for small particles. It was shown that for large particles, the temperature sensitivity and rate exponent decreased as the oxidizer distribution was widened.
Identifying transcription factors and microRNAs as key regulators of pathways using Bayesian inference on known pathway structures

Background Transcription factors and microRNAs act in concert to regulate gene expression in eukaryotes. Numerous computational methods based on sequence information are available for the prediction of target genes of transcription factors and microRNAs. Although these methods provide a static snapshot of how genes may be regulated, they are not effective for the identification of condition-specific regulators.
A Comparison of Face Detection Algorithms

We present a systematic comparison of the techniques used in some of the most successful neurally inspired face detectors. We report three main findings: First, we present a new analysis of how the SNoW algorithm of Roth, Yang, and Ahuja (200) achieves its high performance. Second, we find that representations based on local receptive fields such as those in Rowley, Baluja, and Kanade consistently provide better performance than full connectivity approaches. Third, we find that ensemble techniques, especially those using active sampling such as AdaBoost and Bootstrap, consistently improve performance.
Recollections of Max Born

This article is essentially the text of lectures presented September 7, 1982 at the Max Born Centenary Conference held in Edinburgh, Scotland and October 21, 1982 at the Max Born Symposium held during the Annual Meeting of the Optical Society of America.
Relative Angles-Only Navigation and Pose Estimation for Autonomous Orbital Rendezvous

This paper explores the potential of using angles-only navigation to perform various autonomous orbital rendezvous and close proximity operations. A 32-state extended Kalman filter is developed that processes angular measurements from an optical navigation camera along with gyro and star tracker data to estimate the inertial position, velocity, attitude, and angular rates of both a target and chaser vehicle. The target satellite is assumed to be passive while the chaser may perform a variety of autonomous rendezvous and close proximity maneuvers. The navigation filter’s performance is evaluated and tested by running a coded prototype in a closed loop 6 degree-of-freedom simulation tool containing the various sensors, actuators, GN&C flight algorithms, and dynamics associated with a simple rendezvous scenario. The analysis performed for this study uses standard Monte-Carlo techniques. These results not only include the navigation errors associated with implementing an angles-only navigation scheme, but they also reveal the dispersions from the nominal trajectory associated with this particular technique in a closed-loop GN&C setting. The rendezvous scenario duplicates a similar close proximity scenario analyzed using linear covariance analysis. Both methods are compared to add validity to the results and highlight the advantages and potential of each approach for autonomous orbital rendezvous and close proximity operation analysis.
Worst-Case Background Knowledge for Privacy-Preserving Data Publishing

Recent work has shown the necessity of considering an attacker's background knowledge when reasoning about privacy in data publishing. However, in practice, the data publisher does not know what background knowledge the attacker possesses. Thus, it is important to consider the worst-case. In this paper, we initiate a formal study of worst-case background knowledge. We propose a language that can express any background knowledge about the data. We provide a polynomial time algorithm to measure the amount of disclosure of sensitive information in the worst case, given that the attacker has at most k pieces of information in this language. We also provide a method to efficiently sanitize the data so that the amount of disclosure in the worst case is less than a specified threshold.
How Does Risk Management Influence Production Decisions? Evidence from a Field Experiment

Weather is a key source of income risk, especially in emerging market economies. This paper uses a randomized controlled trial involving Indian farmers to study how an innovative rainfall insurance product affects production decisions. The authors find that insurance provision induces farmers to invest more in higher-return but rainfall-sensitive cash crops, particularly among educated farmers. This shift in behavior occurs ex ante, when realized monsoon rainfall is still uncertain. The results suggest that financial innovation can mitigate the real effects of uninsured production risk.
An automated cluster finder: the adaptive matched filter

We describe an automated method for detecting clusters of galaxies in imaging and redshift galaxy surveys. The adaptive matched filter (AMF) method utilizes galaxy positions, magnitudes, and—when available—photometric or spectroscopic redshifts to find clusters and determine their redshift and richness. The AMF can be applied to most types of galaxy surveys, from two-dimensional (2D) imaging surveys, to multiband imaging surveys with photometric redshifts of any accuracy (2.5 dimensional [2½D]), to three-dimensional (3D) redshift surveys. The AMF can also be utilized in the selection of clusters in cosmological N-body simulations. The AMF identifies clusters by finding the peaks in a cluster likelihood map generated by convolving a galaxy survey with a filter based on a model of the cluster and field galaxy distributions. In tests on simulated 2D and 2½D data with a magnitude limit of r'≈23.5, clusters are detected with an accuracy of Δz≈0.02 in redshift and ~10% in richness to z0.5. Detecting clusters at higher redshifts is possible with deeper surveys. In this paper we present the theory behind the AMF and describe test results on synthetic galaxy catalogs.
Charged black hole in a canonical ensemble

We consider the thermodynamics of a charged black hole enclosed in a cavity. The charge in the cavity and the temperature at the walls are fixed, yielding a canonical ensemble. We derive the phase structure and stability of black hole equilibrium states. We compare our results to that of other work which uses asymptotically anti-de Sitter (AdS) boundary conditions to define the thermodynamics. The thermodynamic properties have extensive similarities which suggest that the idea of AdS holography is more dependent on the existence of the boundary than on the exact details of asymptotically AdS metrics.
Latitudinal motions of the aurora during substorms

Sequences of auroral images obtained with Dynamics Explorer 1 are used to investigate latitudinal motions of the aurora in substorms. Average speeds of poleward motion are about 230 m/s near local midnight for two isolated, small substorms and about 1000 m/s during an intensification within a previously active auroral oval. The speed of poleward expansion measured at about 6-min temporal resolution can differ greatly from the average speed because of the episodic development of substorms. Recovery of the high-latitude boundary of the aurora to presubstorm latitudes is first observed in the postmidnight sector. In the premidnight sector the discrete aurora can become stationary for a period of time or even continue further poleward before a retreat to lower latitudes begins. During the recovery phase, a prominent decrease in luminosities is first observed at intermediate latitudes within the auroral distribution. This region is bounded at higher latitudes by the discrete aurora and at lower latitudes by bright diffuse aurora. Given that magnetic field lines threading these auroral distributions map to the plasma sheet boundary layer and to the central plasma sheet, respectively, magnetic field lines at the intermediate auroral latitudes then map to the plasma sheet at distances of more than about 22 earth radii.
Autonomous exoskeleton reduces metabolic cost of human walking during load carriage

Many soldiers are expected to carry heavy loads over extended distances, often resulting in physical and mental fatigue. In this study, the design and testing of an autonomous leg exoskeleton is presented. The aim of the device is to reduce the energetic cost of loaded walking. In addition, we present the Augmentation Factor, a general framework of exoskeletal performance that unifies our results with the varying abilities of previously developed exoskeletons. We developed an autonomous battery powered exoskeleton that is capable of providing substantial levels of positive mechanical power to the ankle during the push-off region of stance phase. We measured the metabolic energy consumption of seven subjects walking on a level treadmill at 1.5 m/s, while wearing a 23 kg vest. During the push-off portion of the stance phase, the exoskeleton applied positive mechanical power with an average across the gait cycle equal to 23 ± 2 W (11.5 W per ankle). Use of the autonomous leg exoskeleton significantly reduced the metabolic cost of walking by 36 ± 12 W, which was an improvement of 8 ± 3% (p = 0.025) relative to the control condition of not wearing the exoskeleton. In the design of leg exoskeletons, the results of this study highlight the importance of minimizing exoskeletal power dissipation and added limb mass, while providing substantial positive power during the walking gait cycle.
Mesh routing topologies for multi-FPGA systems

There is currently great interest in using fixed arrays of FPGAs for logic emulators, custom computing devices, and software accelerators. An important part of designing such a system is determining the proper routing topology to use to interconnect the FPGAs. This topology can have a great effect on the area and delay of the resulting system. Crossbar, Hierarchical Crossbar, and Mesh interconnection schemes have all been proposed for use in FPGA-based systems. In this paper, we examine Mesh interconnection schemes, and propose several constructs for more efficient topologies. These reduce interchip delays by more than 60% over the basic four-way Mesh.
Quantum versus classical learnability

Motivated by work on quantum black-box query complexity, we consider quantum versions of two well-studied models of learning Boolean functions: Angluin's (1988) model of exact learning from membership queries and Valiant's (1984) Probably Approximately Correct (PAC) model of learning from random examples. For each of these two learning models we establish a polynomial relationship between the number of quantum versus classical queries required for learning. Our results provide an interesting contrast to known results which show that testing black-box functions for various properties can require exponentially more classical queries than quantum queries. We also show that under a widely held computational hardness assumption there is a class of Boolean functions which is polynomial-time learnable in the quantum version but not the classical version of each learning model; thus while quantum and classical learning are equally powerful from an information theory perspective, they are different when viewed from a computational complexity perspective.
Periodic One-Dimensional Hopping Model with One Mobile Directional Impurity

Analytic solution is given in the steady-state limitt→∞ for the system of master equations describing a random walk on one-dimensional periodic lattices with arbitrary hopping rates containing one mobile directional impurity (defect bond). Due to the defect, translational invariance is broken, even if all other rates are identical. The structure of master equations leads naturally to the introduction of a new entity, associated with the walker-impurity pair which we call the quasiwalker. The velocities and diffusion constants for both the random walker and impurity are given, being simply related to that of the quasiparticle through physically meaningful equations. Applications in driven diffusive systems are shown, and connections with the Duke-Rubinstein reptation models for gel electrophoresis are discussed.
On Trapping Sets and Guaranteed Error Correction Capability of LDPC Codes and GLDPC Codes

The relation between the girth and the guaranteed error correction capability of ? -left-regular low-density parity-check (LDPC) codes when decoded using the bit flipping (serial and parallel) algorithms is investigated. A lower bound on the size of variable node sets which expand by a factor of at least 3 ?/4 is found based on the Moore bound. This bound, combined with the well known expander based arguments, leads to a lower bound on the guaranteed error correction capability. The decoding failures of the bit flipping algorithms are characterized using the notions of trapping sets and fixed sets. The relation between fixed sets and a class of graphs known as cage graphs is studied. Upper bounds on the guaranteed error correction capability are then established based on the order of cage graphs. The results are extended to left-regular and right-uniform generalized LDPC codes. It is shown that this class of generalized LDPC codes can correct a linear number of worst case errors (in the code length) under the parallel bit flipping algorithm when the underlying Tanner graph is a good expander. A lower bound on the size of variable node sets which have the required expansion is established.
A survey of patient acceptance of resect and discard for diminutive polyps

Background and Aims Resect and discard is a new paradigm for management of diminutive colon polyps. Little is known regarding whether patients would accept resect and discard. We surveyed colonoscopy patients and their drivers regarding acceptance of resect and discard. Methods This was a cross-sectional survey of colonoscopy outpatients and their drivers at two outpatient academic endoscopy centers. Results Four hundred fifteen colonoscopy patients and 293 drivers completed the survey (93.5% of all invited participants). Results for the two groups were similar. Overall, 66.3% indicated they would accept resect and discard. Participants who were younger, white, and seen at the ambulatory surgery center (vs the hospital outpatient department) were more likely to accept. Those declining resect and discard were more likely to be willing to pay some amount out-of-pocket to have diminutive polyps checked by pathology (97.1% vs 44.5%). Of those unwilling to accept resect and discard, 49.8% would require a zero chance of cancer in diminutive polyps before accepting resect and discard. Conclusions Patient acceptance of resect and discard appears promising but is quite variable. Eliciting individual patient acceptance of resect and discard will be important during initial implementation into clinical practice.
Higher rank case of Dwork's conjecture

JOURNAL OF THE AMERICAN MATHEMATICAL SOCIETY Volume 00, Number 0, Xxxx XXXX, Pages 000–000 S 0894-0347(XX)0000-0 arXiv:math/0005309v1 [math.NT] 9 May 2000 HIGHER RANK CASE OF DWORK’S CONJECTURE DAQING WAN Dedicated to the memory of Bernard Dwork 1. Introduction In this series of two papers, we prove the p-adic meromorphic continuation of the pure slope L-functions arising from the slope decomposition of an overconvergent F- crystal, as conjectured by Dwork [6]. More precisely, we prove a suitable extension of Dwork’s conjecture in our more general setting of σ-modules, see section 2 for precise definitions of the various notions used in this introduction. Our main result is the following theorem. Theorem 1.1. Let X be a smooth affine variety defined over a finite field F q of characteristic p > 0. Let (M, φ) be a finite rank overconvergent σ-module over X/F q . Then, for each rational number s, the pure slope s L-function L s (φ, T ) attached to φ is p-adic meromorphic everywhere. The proof of this theorem will be completed in two papers. In the present higher rank paper, we introduce a reduction approach which reduces Theorem 1.1 to the special case when the slope s (s = 0) part of φ has rank one and the base space X is the simplest affine space A n . This part is essentially algebraic. It depends on Monsky’s trace formula, Grothendieck’s specialization theorem, the Hodge-Newton decomposition and Katz’s isogeny theorem. In our next paper [23], we will handle the rank one case over the affine space A n . The rank one case is very much analytic in nature and forces us to work in a more difficult infinite rank setting, generalizing and improving the limiting approach introduced in [19]. Dwork’s conjecture grew out of his attempt to understand the p-adic analytic variation of the pure pieces of the zeta function of a variety when the variety moves through an algebraic family. To give an important geometric example, let us con- sider the case that f : Y → X is a smooth and proper morphism over F q with a smooth and proper lifting to characteristic zero. Berthelot’s result [1] says that the relative crystalline cohomology R i f crys,∗ Z p modulo torsion is an overconvergent F-crystal M i over X. Applying Theorem 1.1, we conclude that the pure L-functions arising from these geometric overconvergent F-crystals M i are p-adic meromorphic. In particular, this implies the existence of an exact p-adic formula for geometric p-adic character sums and a suitable p-adic equi-distribution theorem for the roots of zeta functions. For more detailed arithmetic motivations and further open prob- lems, see the expository papers [20][21]. 1991 Mathematics Subject Classification. Primary 11G40, 11S40; Secondary 11M41, 14G15. Key words and phrases. L-functions, p-adic meromorphic continuation, σ-modules. This work was partially supported by NSF. c American Mathematical Society
Organocatalytic asymmetric direct vinylogous aldol reactions of γ-crotonolactone with aromatic aldehydes

The direct aldol reaction of γ-crotonolactone and various aromatic aldehydes is catalyzed by bifunctional aminothiourea and aminosquaramide organocatalysts to provide diastereomerically and enantiomerically enriched 5-substituted 2(5H) furanones (γ-butenolides). The reaction is a simple alternative to the classical vinylogous aldol reaction of silyloxy furans.
A simple mechanism for higher-order correlations in integrate-and-fire neurons.

Recent work [1] shows that common input gives rise to higher-order correlations in the Dichotomized Gaussian neuron model. Here we study a homogeneous population of integrate-and-fire neurons receiving correlated input. Each neuron receives an independent white noise input and all neurons receive a common Gaussian input. To quantify the contributions of higher-order correlations we use a maximum entropy model. The model with interactions up to second order (i.e. pairwise correlations) is known as the Ising model. The Kullbach-Leibler divergence between the Ising model and the model with interactions of all orders allows us to quantitatively describe the presence of higher-order correlations. We observe from numerical simulations that for low firing rates, the Kullbach-Leibler divergence grows with increasing correlation i.e. strength of the common input (Figure ​(Figure1A).1A). For population size N=100, the Ising model predicts a vastly different distribution of spike outputs (Figures ​(Figures11B,C). Figure 1 A, KL-divergence grows with increasing correlation between the neurons. B, Distribution of spike outputs from numerical simulation of LIF neurons. C, Predicted distribution of spike outputs from Ising model. For a leaky IF or exponential IF neuron receiving an input signal identical in all trials, and a background noise independent from trial to trial, it is possible to explicitly calculate the linear response function [2,3]. We use this linear filter to compute instantaneous firing probabilities for the N cells in our setup. This gives us a theoretical basis for our central finding that strong higher-order correlations arise naturally in integrate and fire cells receiving common inputs.
Kosha: A Peer-to-Peer Enhancement for the Network File System

The storage needs of modern scientific applications are growing exponentially, and designing economical storage solutions for such applications – especially in Grid environments – is an important research topic. This work presents Kosha, a system that aims to harvest redundant storage space on cluster nodes and user desktops to provide a reliable, shared file system that acts as a large distributed storage. Kosha utilizes peer-to-peer (p2p) mechanisms to enhance the widely-used Network File System (NFS). P2P storage systems provide location transparency, mobility transparency, load balancing, and file replication – features that are not available in NFS. On the other hand, NFS provides hierarchical file organization, directory listings, and file permissions, which are missing from p2p storage systems. By blending the strengths of NFS and p2p storage systems, Kosha provides a low overhead storage solution. Our experiments show that compared to unmodified NFS, Kosha introduces a 3.3% fixed overhead and 4.5% additional overhead as nodes are increased from two to sixteen. For larger number of nodes, the additional overhead increases slowly. Kosha achieves load balancing in distributed directories, and guarantees $99.99\%$ or better file availability.
Socioeconomic Determinants of Child Health: Empirical Evidence from Indonesia†

This paper characterizes the socioeconomic determinants of child health using height-for-age z-score (HAZ), a long-run measure of chronic nutritional deficiency. We construct a panel data that follows children between ages 3 and 59 months in 1993 through the 1997 and 2000 waves of the Indonesian Family Life Survey. We use this data to identify the various child-level, household-level and community-level factors that affect children's health. Our findings indicate that household income has a large and statistically significant role in explaining improvements in HAZ. We also find a strong positive association between parental height and HAZ. At the community level, we find that provision of electricity and the availability of paved roads are positively associated with improvements in HAZ. Finally, in comparison to community-level factors, household-level characteristics play a large role in explaining the variation in HAZ. These findings suggest that policies that address the demand-side constraints have greater potential to improve children's health outcomes in the future.
Communication Patterns as Determinants of Organizational Identification in a Virtual Organization

Recent advances in information technologies provide employees the freedom to work from any place and at any time. Such temporal and spatial dispersion, however, threatens the very meaning of firms. We suggest that organizational identification may be the critical glue linking virtual workers and their organizations. We explore the role that information technologies play in the creation and maintenance of a common identity among decoupled organization members.
Health Literacy Impact on National Healthcare Utilization and Expenditure

Background Health literacy presents an enormous challenge in the delivery of effective healthcare and quality outcomes. We evaluated the impact of low health literacy (LHL) on healthcare utilization and healthcare expenditure. Methods Database analysis used Medical Expenditure Panel Survey (MEPS) from 2005-2008 which provides nationally representative estimates of healthcare utilization and expenditure. Health literacy scores (HLSs) were calculated based on a validated, predictive model and were scored according to the National Assessment of Adult Literacy (NAAL). HLS ranged from 0-500. Health literacy level (HLL) and categorized in 2 groups: Below basic or basic (HLS <226) and above basic (HLS ≥226). Healthcare utilization expressed as a physician, nonphysician, or emergency room (ER) visits and healthcare spending. Expenditures were adjusted to 2010 rates using the Consumer Price Index (CPI). A Pvalue of 0.05 or less was the criterion for statistical significance in all analyses. Multivariate regression models assessed the impact of the predicted HLLs on outpatient healthcare utilization and expenditures. All analyses were performed with SAS and STATA®11.0 statistical software. Results The study evaluated 22 599 samples representing 503 374 648 weighted individuals nationally from 2005-2008. The cohort had an average age of 49 years and included more females (57%). Caucasian were the predominant racial ethnic group (83%) and 37% of the cohort were from the South region of the United States of America. The proportion of the cohort with basic or below basic health literacy was 22.4%. Annual predicted values of physician visits, nonphysician visits, and ER visits were 6.6, 4.8, and 0.2, respectively, for basic or below basic compared to 4.4, 2.6, and 0.1 for above basic. Predicted values of office and ER visits expenditures were $1284 and $151, respectively, for basic or below basic and $719 and $100 for above basic (P < .05). The extrapolated national estimates show that the annual costs for prescription alone for adults with LHL possibly associated with basic and below basic health literacy could potentially reach about $172 billion. Conclusion Health literacy is inversely associated with healthcare utilization and expenditure. Individuals with below basic or basic HLL have greater healthcare utilization and expendituresspending more on prescriptions compared to individuals with above basic HLL. Public health strategies promoting appropriate education among individuals with LHL may help to improve health outcomes and reduce unnecessary healthcare visits and costs.