cssi/SciSciGPT-SciSciNet huggingface dataset:
Toda lattice, cohomology of compact Lie groups and finite Chevalley groups

In this paper, we describe a connection that exists among (a) the number of singular points along the trajectory of Toda flow, (b) the cohomology of a compact subgroup $K$, and (c) the number of points of a Chevalley group $K({\mathbb F}_q)$ related to $K$ over a finite field ${\mathbb F}_q$. The Toda lattice is defined for a real split semisimple Lie algebra $\mathfrak g$, and $K$ is a maximal compact Lie subgroup of $G$ associated to $\mathfrak g$. Relations are also obtained between the singularities of the Toda flow and the integral cohomology of the real flag manifold $G/B$ with $B$ the Borel subgroup of $G$ (here we have $G/B=K/T$ with a finite group $T$). We also compute the maximal number of singularities of the Toda flow for any real split semisimple algebra, and find that this number gives the multiplicity of the singularity at the intersection of the varieties defined by the zero set of Schur polynomials.
Overbanked and Credit-Starved: A Paradox of the Transition

Abstract This paper demonstrates how the behavior of credit markets in a transition-like environment can be a function of the market structure in the commercial lending sector that was inherited from the prereform economy. Using a game theoretic model, we investigate one possible explanation for how a more crowded banking sector can diminish the scale of commercial lending in a market in which information on borrower quality and third party contract enforcement are lacking initially. The model sheds additional light on the stunted development of commercial bank lending in post-Soviet Russia. J. Comp. Econ. , March 2002, 30 (1), pp. 25–50. Middlebury College, Middlebury, Vermont 05753. © 2002 Elsevier Science (USA). Journal of Economic Literature Classification Numbers: P34, G21, L13.
Dividend Payout and Future Earnings Growth

Because dividends reduce the funds available for investment, many market observers and investors associate high dividend payout with weak future earnings growth. Tests using aggregate market data, however, provided evidence that contradicts that view. Because aggregate results may not apply at the company level, we conducted a company-by-company analysis of the relationship between payout and future earnings growth. Our tests also show that high-dividend-payout companies tend to experience strong, not weak, future earnings growth. These results are robust to alternative measures of payout and earnings, sample composition, mean reversion in earnings, the effects of particular industries, time periods, and share repurchases.
Chandra multi‐wavelength plane (ChaMPlane) survey: design and initial results

The Chandra Multiwavength Plane (ChaMPlane) Survey of the galactic plane incorporates serendipitous sources from selected Chandra pointings in or near the galactic plane (b 10-100), neutron stars and black holes (quiescent low mass X-ray binaries) to constrain their space densities and thus origin and evolution. Secondary objectives are to identify Be stars in high mass X-ray binaries and constrain their space densities, and to survey the H-R diagram for stellar coronal sources. A parallel optical imaging under the NOAO Long Term Survey program provides deep optical images using the Mosaic imager on the CTIO and KPNO 4-m telescopes. The 36′ × 36′ optical images (Hα, R, V and I) cover ∼ 5× the area of each enclosed Chandra ACIS FOV, providing an extended survey of emission line objects for comparison with Chandra. Spectroscopic followup of optical counterparts is then conducted, thus far with WIYN and Magellan. The X-ray preliminary results from both the Chandra and optical surveys will be presented, including logN-logS vs. galactic position (l,b) and optical identifications.
Intramolecular addition of alkyllithiums to acetylenes: Regiospecific 4-, 5-, and 6-exo-dig cyclizations

Abstract Primary acetylenic alkyllithiums bearing a phenyl substituent on the triple bond, which may be prepared in virtually quantitative yield by low-temperature lithium-iodine interchange, undergo regiospecific exo-dig cyclization via stereoselective syn-addition of CH 2 Li to the carbon-carbon triple bond to give four-, five-, and six-membered carbocycles bearing an easily functionalized exocyclic lithiomethylidene moiety. Cyclization of the analogous alkyl substituted acetylenic alkyllithiums is confined to the 5- exo-dig mode.
Bond modulus and stability of covalent solids

The chemical stabilities of molecules are determined by their LUMO–HOMO energy gaps. For solids, the analogues of these are their energy band gaps. However, solids are aggregates of molecules, so an energy alone cannot characterize their stabilities. An intensive parameter is needed. Such a parameter is the gap energy per molecular volume. The author has coined the name ‘bond modulus’ for this parameter because it tends to be proportional to elastic moduli and it has the same dimensions. It applies primarily to covalent solids with localized bonding. It is proportional to chemical hardnesses and bulk moduli, as well as octahedral shear moduli and inverse polarizabilities.
The cooling and condensation of flare coronal plasma

A model is investigated for the decay of flare heated coronal loops in which rapid radiative cooling at the loop base creates strong pressure gradients which, in turn, generate large (supersonic) downward flows. The coronal material cools and 'condenses' onto the flare chromosphere. The features which distinguish this model from previous models of flare cooling are: (1) most of the thermal energy of the coronal plasma may be lost by mass motion rather than by conduction or coronal radiation; (2) flare loops are not isobaric during their decay phase, and large downward velocities are present near the footpoints; (3) the differential emission measure q has a strong temperature dependence.
Risk factors for noncompliance with glaucoma follow-up visits in a residents’ eye clinic

Abstract Objective This study aimed to identify factors associated with compliance with glaucoma follow-up visits. Design Computer records of a university residents' eye clinic were reviewed to identify a random sample of all persons who had an examination with International Classification of Disease (ICD) 9 coding (ICD9) for glaucoma suspect or glaucoma during a 2-year period (1991-1993) to undergo telephone interview. Participants Those who were seen at least every 6 months regardless of earlier return instructions were defined as compliant with follow-up (controls, n=362). Those who had any lapse between visits of longer than 6 months were defined as noncompliant (cases, n=362). Results Interviews were completed for 196 cases and 242 controls. Noncompliant persons were significantly more likely to be suspects for glaucoma rather than to have definite glaucoma and to be dissatisfied with waiting time in the clinic (29.1% vs. 17.8%, P P Conclusion Compliance with follow-up visits for glaucoma is associated with markers for early disease. Attempts to improve compliance might focus on improved communication of the seriousness of the disease and improvements in clinic waiting time.
Characteristics of Deep Centers Observed in n-GaN Grown by Reactive Molecular Beam Epitaxy

Deep centers in Si-doped n-GaN samples grown on sapphire by reactive molecular beam epitaxy, using different ammonia flow rates (AFRs), have been studied by deep level transient spectroscopy. In addition to five electron traps, which were also found in n-GaN layers grown by both metalorganic chemical-vapor deposition and hydride vapor-phase epitaxy, two new centers C1 (0.43-0.48 eV) and E1 (0.25 eV) have been observed. C1, whose parameters show strong electric-field effects and anomalous electron capture kinetics, might be associated with dislocations. E1, which is very dependent on the AFR, exhibits an activation energy close to that of a center created by electron irradiation and is believed to be a defect complex involving VN.
The KOH terms and classes of unimodal N-modular diagrams

We show how certain suitably modified N-modular diagrams of integer partitions provide a nice combinatorial interpretation for the general term of Zeilberger@?s KOH identity. This identity is the reformulation of O@?Hara@?s famous proof of the unimodality of the Gaussian polynomial as a combinatorial identity. In particular, we determine, using different bijections, two main natural classes of modular diagrams of partitions with bounded parts and length, having the KOH terms as their generating functions. One of our results greatly extends recent theorems of J. Quinn et al., which presented striking applications to quantum physics.
The attenuation of sound propagating through a radial diffuser with absorptive walls

Abstract An analytical model for acoustic propagation through an idealized radial diffuser under zero flow conditions has been developed. The model has been used to generate a computer program which is capable of predicting radial attenuation for a variety of diffuser wall impedance combinations. Numerical results are presented for the following three cases: (i) one hard diffuser wall and one finite impedance wall, (ii) equal finite impedance diffuser walls, and (iii) unequal finite impedance diffuser walls. The results for cases (i) and (ii) are found to be in good agreement with analytical results from the literature.
Carbenes in Synthesis and Homogeneous Catalysis

N-heterocyclic carbenes are excellent supporting ligands for Rh and Ir complexes that can act as catalysts for hydrogen transfer and Heck reactions. Recent developments on synthesis of ligands and complexes and on catalytic applications from our group are reviewed. Design of imidazolium salts to facilitate chelation is discussed as well as abnormal binding of NHCs.
Verifying programs which operate on data structures

In order to prove the correctness of a computer program, one must be able to characterize the data in the program. Proofs by the inductive assertion method require the construction of concise, precise assertions to describe the data. This paper presents some techniques for characterizing data structures which can be used to build adequate assertions. New primitive relations are introduced for describing intra-structural relationships. These primitives form the basis for two important concepts: The invariant of a structure is a concise characterization of a structural class. A representation function is a mapping from a structure to a corresponding abstract data object; this concept provides a means for expressing relationships between a structure and other data, and among the values of a structure over time. By means of verification lemmas, these concepts can be integrated into proofs of correctness, and the proofs as well as the assertions can be dramatically simplified. An example program is presented which demonstrates the use of these concepts in constructing the assertions, and the resulting proof of correctness is outlined.
Guanabenz-related amidinohydrazones: potent non-azole inhibitors of aldosterone biosynthesis

Abstract A new series of potent, guanabenz-derived, non-steroidal aldosterone biosynthesis inhibitors are presented. Salient features of the structure-activity relationship indicate the requirement of a hydrophobic core, presence of a hydrophilic (or basic) peripheral appendage, and, in some cases, profound dependence on hydrazone stereochemistry. The most potent compound of the series, 29, was 2 orders of magnitude more potent than guanabenz as an aldosterone biosynthesis inhibitor.
Taking Terrain Literally: Grounding Local Adaptation to Corporate Social Responsibility in the Extractive Industries

Since the early 1990s, the extractive industries have increasingly valued corporate social responsibility (CSR) in the communities where they operate. More recently, these industries have begun to recognize the importance of adapting CSR efforts to unique local contexts rather than applying a one-size-fits-all model. However, firms understand local context to mean culture and treat the physical properties of the host region—topography, geology, hydrology, and climate—as the exclusive purview of mineral geologists and engineers. In this article, we examine the organization of CSR at two industrial-scale gold mines in Guatemala, owned by the same firm, which yielded starkly distinct levels of support among host community residents. We develop the idea of social terrain to convey the way in which the biophysical environment informs local social relations and imbues phenomena with particular social meanings. We argue that firms must account for social terrain in organizing for CSR. The literature struggles to provide guidelines for identifying and understanding stakeholders. Social terrain, we argue, can begin to bridge this gap between theory and practice.
FERMIONIC CHARACTER SUMS AND THE CORNER TRANSFER MATRIX

We present a "natural finitization" of the fermionic q-series (certain generalizations of the Rogers–Ramanujan sums) which were recently conjectured to be equal to Virasoro characters of the unitary minimal conformal field theory (CFT) ℳ (p, p + 1). Within the quasi-particle interpretation of the fermionic q-series this finitization amounts to introducing an ultraviolet cutoff, which — contrary to a lattice spacing — does not modify the linear dispersion relation. The resulting polynomials are conjectured (proven, for p = 3, 4) to be equal to corner transfer matrix (CTM) sums which arise in the computation of order parameters in regime III of the r = p + 1 RSOS model of Andrews, Baxter and Forrester. Following Schur's proof of the Rogers–Ramanujan identities, these authors have shown that the infinite lattice limit of the CTM sums gives what later became known as the Rocha–Caridi formula for the Virasoro characters. Thus we provide a proof of the fermionic q-series representation for the Virasoro characters for p = 4 (the case p = 3 is "trivial"), in addition to extending the remarkable connection between CFT and off-critical RSOS models. We also discuss finitizations of the CFT modular-invariant partition functions.
Optical resolution of rotenoids

Optical resolution of selected rotenoids containing 1-3 asymmetric centers in dihydrobenzopyranofuroben-zopyranone and dihydrobisbenzopyranopyranone series has been achieved on two chiral high-performance liquid chromatographic (hplc) stationary phases. In most cases, the absolute stereochemistry at the cis-B/C ring junction of the rotenoidal antipodes can be related to their elution order. Generally, the 6aα,12aα-enantiomers were more strongly retained by the chiral substrate than their corresponding optical antipodes. The elution-configuration relationship provides potential utility for predicting the absolute configuration of related rotenoidal compounds. Chiral phase hplc on amino-acid-bonded-silica yielded results explicable in terms of Pirkle's bonding schemes for chiral recognition. Resolution data for 12a-hydroxy-, 12a-methoxy-, and 12-hydroxyiminorotenoids further corroborate the mechanistic rationale, and demonstrate that nonpolar π-π interactions appeared to be important for enantiomeric separation on helic poly-triphenylmethylacryl-ate-silica (CPOT). In the latter system, steric effects and conformational factors in association with the modification of E-ring structures might play significant roles in the chiral separation process in view of the reversal to the elution order observed for all methoxylated rotenoids and elliptone derivatives including the parent deguelin. The unique separability (α = 1.44) of 12a-hydroxyelliptone on CPOT was suggestive of structural effects of the 5′-side chain on the resolution of the rotenoids having a five-membered-E-ring. The results obtained with two different types of chiral phases are complementary and useful for optical resolution of a wide variety of natural and synthetic rotenoidal compounds.
Sinterability of Agglomerated Powders

A concept is presented which relates the sinterability of a powder compact to its particle arrangement as defined by the distribution of pore coordination numbers, i.e., the number of touching particles surrounding and defining each void space. Previous thermodynamic arguments suggest that pores will disappear only when their coordination numbers are less than a critical value. The coordination-number distribution of an agglomerated powder is discussed with respect to the size of the multiple-particle packing unit, consolidation forces, and phenomena occurring during sintering. One pertinent conclusion is that the multiple-particle packing units densify and support grain growth as sintering initiates. Grain growth and rearrangement processes decrease the coordination number of remaining pores to allow them to disappear during latter states of sintering. Porosimetry and direct observations of powder compacts of <1 μm Al2O3 heat-treated between 600° and 1600°C support this concept.
Footprints of statistical anisotropies

We propose and develop a formalism to describe and constrain statistically anisotropic primordial perturbations. Starting from a decomposition of the primordial power spectrum in spherical harmonics, we find how the temperature fluctuations observed in the CMB sky are directly related to the coefficients in this harmonic expansion. Although the angular power spectrum does not discriminate between statistically isotropic and anisotropic perturbations, it is possible to define analogous quadratic estimators that are direct measures of statistical anisotropy. As a simple illustration of our formalism we test for the existence of a preferred direction in the primordial perturbations using full-sky CMB maps. We do not find significant evidence supporting the existence of a dipole component in the primordial spectrum.
A Methodology for LISP Program Construction from Examples

An automatic programming system, THESYS, for constructing recursive LISP programs from examples of what they do is described. The construction methodology is illustrated as a series of transformations from the set of examples to a program satisfying the examples. The transformations consist of (1) deriving the specific computation associated with a specific example, (2) deriving control flow predicates, and (3) deriving an equivalent program specification in the form of recurrence relations. Equivalence between certain recurrence relations and various program schemata is proved. A detailed description of the construction of four programs is presented to illustrate the application of the methodology.
Algorithmic mechanism design for load balancing in distributed systems

Computational grids are promising next-generation computing platforms for large-scale problems in science and engineering. Grids are large-scale computing systems composed of geographically distributed resources (computers, storage etc.) owned by self interested agents or organizations. These agents may manipulate the resource allocation algorithm in their own benefit, and their selfish behavior may lead to severe performance degradation and poor efficiency. In this paper, we investigate the problem of designing protocols for resource allocation involving selfish agents. Solving this kind of problems is the object of mechanism design theory. Using this theory, we design a truthful mechanism for solving the static load balancing problem in heterogeneous distributed systems. We prove that using the optimal allocation algorithm the output function admits a truthful payment scheme satisfying voluntary participation. We derive a protocol that implements our mechanism and present experiments to show its effectiveness.
The historical development, and predicted state-of-the-art of the general-purpose digital computer

Some of the important characteristics of all the general-purpose digital computers that have ever been built, or are in the process of being built, have been collected together in order to show the changes in performance and characteristics during the passage of time. These collected data, as well as information regarding recent development work, have been used to extrapolate the characteristics and performance figures into the 1960--1965 era. The report considers such characteristics as add and multiply times, memory characteristics, pulse repetition rates, and internal system parameters.The collected data seems to suggest that the majority of the computers developed between now and 1965 will show very little change in performance from that which was obtained during the last five years. However, a few research machines will definitely advance the technology, possibly as much as one order of magnitude for some of the characteristics. In appendix B there is a listing of approximately 300 different computers, in an attempt to provide an initial directory of the world's computers.
Finite element embedding with optical interference

Abstract A convenient algorithm for calculating the overall reflectivity from, and the absorptivity in each layer of, a multi-thin-film array is reported. To account properly for interference the radiative transfer problem is formulated in terms of the amplitude of the electric field vector rather than the radiant flux or intensity. Commencing with a substrate, the system coefficients are constructed by finite element embedding. When the embedding builds to the top of the array, the field amplitude is assigned a normalized value of unity, and the remaining amplitudes are back calculated step by step. The Poynting Theorem permits the normalized fluxes to be found, and differencing then gives the absorptivity of each layer. Absorbing media, polarization, interference, and oblique incidence are all fully included. The absorptivity-per-layer values are needed in analyzing the cooling requirements of laser mirrors and absorbers used with high concentration solar collectors.
Mourning, Yearning, Cruising: Ernesto Pujol's Memorial Gestures

This paper analyzes Ernesto Pujol's performance titled 'Memorial Gestures: Mourning and Yearning at the Rotunda,' performed at the Chicago Cultural Center in October 2007. The central theme of the twelve-hour, silent performance was the mourning of soldiers lost in war, but the work invoked larger narratives of rapport and loss in order to address this theme. Focusing on the use of bodily communication used by the performers to maintain and adapt the work, this essay shows how Pujol's development of this mode of practice drew on analogous types of non-verbal intimacies associated with cruising. Through an analysis of the logistics of the performance practice, the essay shows how the tactics of public, non-verbal communication in cruising were extrapolated to provide a moving rendition of the larger theme of loss. Both mourning and cruising find in silence a space in which the intimate is produced in and as public, and this essay shows how the experiences of queer sexualities can be understood as a resource in the development of public and accessible modes of artistic practice.
Nanowire-organic thin film transistor integration and scale up towards developing sensor array for biomedical sensing applications

Exploratory research works have demonstrated the capability of conducting nanowire arrays in enhancing the sensitivity and selectivity of bio-electrodes in sensing applications. With the help of different surface manipulation techniques, a wide range of biomolecules have been successfully immobilized on these nanowires. Flexible organic electronics, thin film transistor (TFT) fabricated on flexible substrate, was a breakthrough that enabled development of logic circuits on flexible substrate. In many health monitoring scenarios, a series of biomarkers, physical properties and vital signals need to be observed. Since the nano-bio-electrodes are capable of measuring all or most of them, it has been aptly suggested that a series of electrode (array) on single substrate shall be an excellent point of care tool. This requires an efficient control system for signal acquisition and telemetry. An array of flexible TFTs has been designed that acts as active matrix for controlled switching of or scanning by the sensor array. This array is a scale up of the flexible organic TFT that has been fabricated and rigorously tested in previous studies. The integration of nanowire electrodes to the organic electronics was approached by growing nanowires on the same substrate as TFTs and fl ip chip packaging, where the nanowires and TFTs are made on separate substrates. As a proof of concept, its application has been explored in various multi-focal biomedical sensing applications, such as neural probes for monitoring neurite growth, dopamine, and neuron activity; myocardial ischemia for spatial monitoring of myocardium.
The role of exchange rates in intertemporal risk–return relations

Abstract This paper investigates the significance of an intertemporal relation between expected returns on countries’ stock market portfolios and their risk exposures to the world market portfolio. We find that the intertemporal risk–return relation differs significantly under different currency denominations. The slope coefficient is the largest at around seven when the returns are denominated in Japanese yen, moderate at about five when the returns are denominated in the Canadian or US dollars, and the smallest at around three when the returns are denominated in pound or euro and its predecessors. The ranking of the risk–return coefficients across different currency denominations remains the same when we replace country equity indices with global industry portfolios in estimating the intertemporal relations, when we change the return frequency from monthly to daily, and when we consider different specifications for the conditional covariance process.
GLS-detrending and regime-wise stationarity testing in small samples

Abstract The proposed version of the DF-GLS test incorporates up to two breaks in the intercept. While the asymptotic properties of the DF-GLS test remain valid, the changes in the intercept have an impact on the small sample properties of the test.
Length changes of the hamstrings and adductors resulting from derotational osteotomies of the femur

Derotational osteotomies of the femur are frequently performed to treat persons with cerebral palsy who walk with excessive internal rotation of the hip. However, whether these procedures stretch or slacken the surrounding muscles appreciably is unknown. Determination of how muscle lengths are altered by derotational osteotomies is difficult because the length changes depend not only on the osteotomy site and the degree of derotation, but also on the anteversion angle of the femur and the rotational position of the hip. We have developed a three-dimensional computer simulation of derotational osteotomies, tested by anatomical experiments, to examine how femoral anteversion, hip internal rotation, and derotation affect the lengths of the semitendinosus, semimembranosus, biceps femoris long head, adductor longus, adductor brevis, and gracilis muscles. Simulation of derotational osteotomies at the intertrochanteric, subtrochanteric, or supracondylar levels decreased the origin-to-insertion lengths of the hamstrings and gracilis in our model by less than 8 mm (1.8%). Hence, the lengths of the hamstrings and gracilis are not likely to be altered substantially by these procedures. The origin-to-insertion lengths of the adductor longus and adductor brevis decreased less than 4 mm (1.9%) with subtrochanteric correction in our model, but the length of adductor brevis increased 8 mm (6.3%) with 60 degrees of intertrochanteric derotation. These muscles are also unlikely to be affected by derotational osteotomies, unless a large degree of intertrochanteric derotation is performed.
An improved data stream summary: the count-min sketch and its applications

We introduce a new sublinear space data structure--the count-min sketch--for summarizing data streams. Our sketch allows fundamental queries in data stream summarization such as point, range, and inner product queries to be approximately answered very quickly; in addition, it can be applied to solve several important problems in data streams such as finding quantiles, frequent items, etc. The time and space bounds we show for using the CM sketch to solve these problems significantly improve those previously known--typically from 1/e2 to 1/e in factor.
Vortex-phase filtering technique for extracting spatial information from unresolved sources

A white light vortex coronagraph was used to experimentally achieve sub-resolution detection. The angular location of the centroid γ, and the angular extent of circular pinhole sources Θ, were measured to within errors of δγ=±0.015λ/D and δΘ=±0.026λ/D. This technique has two advantages over conventional imaging: simple power measurements are made and shorter exposure times may be required to achieve a sufficient signal-to-noise ratio.
Gauge invariant and gauge fixed D-brane actions

Abstract The first part of this paper presents actions for Dirichlet p-branes embedded in a flat tendimensional space-time. The fields of the (p + 1) -dimensional world-volume theories are the I OD space-time coordinates X, a pair of Majorana-Weyl spinors θ 1 and 02, and a U(1) gauge field A μ . The N = 2A or 2B super-Poincare group in ten dimensions is realized as a global symmetry. In addition the theories have local symmetries consisting of general coordinate invariance of the world-volume, a local fermionic symmetry (called “kappa”), and U(1) gauge invariance. A detailed proof of the kappa symmetry is given that applies to all cases (p = 0, 1, . . . , 9). The second part of the paper presents gauge-fixed versions of these theories. The fields of the IOD ( p = 9) gauge-fixed theory are a single Majorana-Weyl spinor A and the U(1) gauge field A μ . This theory, whose action turns out to be surprisingly simple, is a supersymmetric extension of 10D Born-Infeld theory. It has two global supersymmetries: one represents an unbroken symmetry, and the second corresponds to a broken symmetry for which A is the Goldstone fermion. The gauge-fixed supersymmetric D-brane theories with p > 9 can be obtained from the 10D one by dimensional reduction.
Supersymmetric completion of Gauss-Bonnet combination in five dimensions

Based on superconformal tensor calculus in five dimensions, we construct the supersymmetric completion of Gauss-Bonnet combination. We study the vacuum solutions with AdS 2 × S 3 and AdS 3 × S 2 structures. We also analyze the spectrum around a maximally supersymmetric Minkowski5.
Revealing the Supernova Remnant Population of M33 with Chandra

We present results of a search for supernova remnants (SNRs) in archival Chandra images of M33. We have identified X-ray SNRs by comparing the list of Chandra X-ray sources in M33 with tabulations of SNR candidates identified from (1) elevated [S II]/Hα ratios in the optical and (2) radio spectral indices. In addition, we have searched for optical counterparts to soft sources in the Chandra images and X-ray SNR candidates identified in the XMM-Newton survey of M33. Of the 98 optically known SNRs in M33, 22 have been detected at >3 σ level in the soft band (0.35–1.1 keV). At least four of these SNR candidates are spatially extended based on a comparison of the data to simulated images of point sources. Aside from the optically matching SNRs, we have found one soft X-ray source in M33 that exhibits no optical emission and is coincident with a known radio source. The radio spectral index of this source is consistent with particle acceleration in shocks, leading us to suggest that it is a nonradiative SNR. We have also found new optical counterparts to two soft X-ray SNRs in M33. These counterparts exhibit enhanced [S II]/Hα ratios characteristic of radiative shocks. Pending confirmation from optical spectroscopy, the identification of these two optical counterparts increases the total number of known optically emitting SNRs in M33 to 100. This brings the total number of identified SNRs with X-ray counterparts, including those exclusively detected by the XMM-Newton survey of M33, to 37 SNRs. We find that while there are a similar number of confirmed X-ray SNRs in M33 and the LMC with X-ray luminosities in excess of 1035 ergs s-1, nearly 40% of the LMC SNRs are brighter than 1036 ergs s-1, while only 13% of the M33 sample exceed this luminosity. Including X-ray SNR candidates from the XMM-Newton survey (objects lacking optical counterparts) increases the fraction of M33 SNRs brighter than 1036 ergs s-1 to 22%, still only half the LMC fraction. The differences in luminosity distributions cannot be fully explained by uncertainty in spectral model parameters and are not fully accounted for by abundance differences between the galaxies.
The Loewner Equation: Maps and Shapes

An approach called Schramm–Loewner evolution (SLE) provides a new method for dealing with a wide variety of scale-invariant problems in two dimensions. This approach is based upon an older method called Loewner Evolution (LE), which connects analytic and geometrical constructions in the complex plane. In this paper, the bases of LE and SLE are described and some simple applications are discussed in relatively non-technical form. A bibliography of the subject is presented.
Dynamic scaling of I–V data for the neutral 2D Coulomb gas

Abstract The value of the dynamic critical exponent z has been studied for experimental two-dimensional superconducting and Josephson junction array systems in zero magnetic field via the Fisher–Fisher–Huse dynamic scaling analysis. We found z≃5.6±0.3, a relatively large value indicative of non-diffusive dynamics. We extend this work here to simulational I–V curves that are also found to be characterized by the same large value of z.
Peer effects and the Freshman 15: Evidence from a natural experiment

Abstract This study investigates the importance of peer effects in explaining weight gain among freshman college students. We exploit a natural experiment that takes place on most college campuses in the US – randomized roommate assignments. While previous studies suggest that having an obese spouse, friend, or sibling increases one's likelihood of becoming obese, these social interactions are clearly non-random. We collect data from female students living on campus at a private Midwestern university at the beginning and end of their first year of college. Our findings suggest that the amount of weight gained during the freshman year is strongly and negatively correlated to the roommate's initial weight. Further, our analysis of behaviors suggests that female students adopt some of their roommates’ weight-loss behaviors which cause them to gain less weight than they otherwise would have. In particular, we find evidence that this effect may be through influences in eating, exercise, and use of weight loss supplements.
A Ricardo Model with Economies of Scale

Abstract This paper extends the analysis of the classical n-good two-country Ricardo model of international trade to the case where the production functions have economies of scale. It addresses the technical difficulties inherent in economies of scale by new integer programming and linear programming methods. The analysis reveals the existence of a well defined region which fills in solidly with equilibrium points as the number of goods becomes large. New economic conclusions follow from the ability to analyze these large models, among them that, in the presence of economies of scale, considerable conflict exists between the interests of the two trading partners. Journal of Economic Literature Classification Numbers: C61, C62, C68, F12.
The Effect of NAFTA on Energy and Environmental Efficiency in Mexico

Prior to Mexico's entry to the North American Free Trade Agreement (NAFTA), predictions of the consequent impact on the environment in that country ranged from the dire to very optimistic. This article investigates NAFTA's outcomes in terms of energy use and the emission of atmospheric pollutants. Specifically, has entry into NAFTA led to a convergence or divergence in indicators of emissions, environmental efficiency, and emissions-specific technology in Mexico, the United States, and Canada? A battery of tests is applied to these indicators for energy use and carbon, sulfur, and NOx emissions in the three countries. The results show that the extreme predictions of the outcomes of NAFTA have not materialized. Rather, trends that were already present before the introduction of NAFTA continue and, in some cases, improve post-NAFTA, but not yet in a dramatic way. There is strong evidence of convergence across the three countries toward a lower intensity of energy use and emissions per unit of GDP. Although intensity is rising initially for some variables in Mexico, it eventually begins to fall post-NAFTA. Per capita emissions of sulfur and NOx also show convergence, but this is not the case for energy and carbon, and the latter variables also drift moderately upwards. The state of technology in energy efficiency and sulfur abatement is improving in all countries, although there is little, if any, sign of convergence and NAFTA has no effect on the rate of technology diffusion. However, total energy use and carbon emissions increase both pre- and post-NAFTA and total NOx emissions increase in Mexico. Only total sulfur emissions are stable and falling in all three NAFTA partners.
Effect of Workpart Curvature on the Stiffness Properties of Circular Filamentary Brushes

In this paper the role which workpart geometry plays in the stiffness properties and contact zone characteristics of circular filamentary brushes is investigated. The problem is examined by employing a recently developed mechanics-based procedure for evaluating large filament deformation, in conjunction with appropriate kinematic constraints for filament tip contact with a smooth, rigid workpart of prescribed constant curvature. Numerical examples for a circular filamentary brush system are presented and discussed for the purpose of illustrating the basic nature of brush stiffness response characteristics for a range of prescribed constant-curvature workpart surfaces.
TV-min and greedy pursuit for constrained joint sparsity and application to inverse scattering

This paper proposes a general framework for compressed sensing of constrained joint sparsity (CJS) which includes total variation minimization (TV-min) as an example. TV- and 2-norm error bounds, independent of the ambient dimension, are derived for the CJS version of Basis Pursuit and Orthogonal Matching Pursuit. As an application the results extend Cand`es, Romberg and Tao's proof of exact recovery of piecewise constant objects with noiseless incomplete Fourier data to the case of noisy data.
Phase Relations between the Polytitanates of Barium and the Barium Borates, Vanadates, and Molybdates

Phase equilibria in ternary systems involving BaO, TiO2, and the low melting oxides B2O3, V2O5, and Mo03 are reported. The low-temperature phases BaTi2O5 and BaTi5O11 were not obtained in equilibrium in any of the studied systems. It has been found that the compound reported with the composition Ba3Ti3V4O19 has in fact the composition Ba3TiV4O15. It decomposes at 995 ± 5°C (Ba3TiV4O15→liq+ Ba2V2O7). A new ternary compound Ba2Ti2B2O9 which decomposes into BaTiO3 and a liquid at ∼950°C was also found. Alternative ways to synthesize BaTi4O9 and Ba2Ti9O20 have been found. These compounds can be obtained by heating at relatively low temperature appropriate compositions in the system BaO-TiO2-V2O5 or BaO-TiO2-MoO3 and dissolving the excess phases in dilute HCI. Ba2Ti9O2o can also be prepared at low temperature in the BaO-TiO2-B2O3 system, in which it may show a limited solid solution, offering the possibility of obtaining dense ceramics at low temperature.
Screening consumers through alternative pricing mechanisms

This paper addresses the optimal design of optional nonlinear tariffs. Two particular solutions commonly used in telecommunications and other industries are fully characterized. These optimal outlay schedules illustrate how the tariff design is altered when there exists a time lag between tariff choice and consumption. In this model, consumers' uncertainty is resolved in the interim, between the tariff choice and the usage decision, through changes in their types. The paper studies whether the monopolist may profit from screening consumers according to different information sets, and it shows that expected profits are higher under an ex-post tariff if the variance of the ex-ante type distribution is large enough. The paper also shows that no results regarding social efficiency may be obtained in general. Welfare comparison of optional tariffs will be very sensitive to type distributions, how types enter demand specifications, and the relative variance of the type components.
Posture sway and the transition rate for a fall

Abstract Postural body sway displacements for quiet standing subjects (measured with a new ultrasonic device) are reported. Two of the well-known strategies for balancing, namely ankle and hip movements, were probed. The data are modeled using a Fokker–Planck–Langevin stochastic theory. Both analytic and computer simulation techniques are employed. The Kramers transition rate for a fall is expressed as a function of experimental parameters. The root mean square velocity is especially important for determining the fall probability.
Improving the exact security of digital signature schemes

We put forward a new method of constructing Fiat-Shamir-like signature schemes that yields better "exact security" than the original Fiat-Shamir method. (We also point out, however, that such tight security does not make our modified schemes always preferable to the original ones. Indeed, there exist particularly efficient Fiat-Shamir-like schemes that, though only enjoying "loose security," by using longer keys may provably provide more security at a lower computational cost than their "tight-security" counterparts.)
Satellite navigation: Present and future

The Global Positioning System serves one billion civil users with applications including: navigation for cars, aircraft, ships, spacecraft, pedestrians and emergency services; time transfer for telecommunications, finance and power delivery; and a breadth of scientific uses. Cognizant of this utility, the Russians are rejuvenating their satellite navigation system, and new systems are being fielded by China, Japan, India and Europe. Taken together, this Global Navigation Satellite System will provide geometric diversity with over one hundred navigation satellites all with triple frequency diversity for civil use. This paper and talk will briefly describe the technology with a focus on aviation applications.
Large universal deformation rings

We provide a series of examples of finite groups G and mod p representations V of G whose stable endomorphisms are all given by scalars such that V has a universal deformation ring R(G,V) which is large in the sense that R(G,V)/pR(G,V) is isomorphic to a power series algebra in one variable.
The Disk Population of the Taurus Star-Forming Region

We have analyzed nearly all images of the Taurus star-forming region at 3.6, 4.5, 5.8, 8.0, and 24??m that were obtained during the cryogenic mission of the Spitzer Space Telescope (46 deg2) and have measured photometry for all known members of the region that are within these data, corresponding to 348 sources, or 99% of the known stellar population. By combining these measurements with previous observations with the Spitzer Infrared Spectrograph and other facilities, we have classified the members of Taurus according to whether they show evidence of circumstellar disks and envelopes (classes I, II, and III). Through these classifications, we find that the disk fraction in Taurus, N(II)/N(II+III), is ~75% for solar-mass stars and declines to ~45% for low-mass stars and brown dwarfs (0.01-0.3 M ?). This dependence on stellar mass is similar to that measured for Chamaeleon I, although the disk fraction in Taurus is slightly higher overall, probably because of its younger age (1?Myr versus 2-3?Myr). In comparison, the disk fraction for solar-mass stars is much lower (~20%) in IC 348 and ? Ori, which are denser than Taurus and Chamaeleon I and are roughly coeval with the latter. These data indicate that disk lifetimes for solar-mass stars are longer in star-forming regions that have lower stellar densities. Through an analysis of multiple epochs of Spitzer photometry that are available for ~200 Taurus members, we find that stars with disks exhibit significantly greater mid-infrared (mid-IR) variability than diskless stars, which agrees with the results of similar variability measurements for a smaller sample of stars in Chamaeleon I. The variability fraction for stars with disks is higher in Taurus than in Chamaeleon I, indicating that the IR variability of disks decreases with age. Finally, we have used our data in Taurus to refine the observational criteria for primordial, evolved, and transitional disks. The ratio of the number of evolved and transitional disks to the number of primordial disks in Taurus is 15/98 for spectral types of K5-M5, indicating a timescale of 0.15 ? ?primordial ~ 0.45?Myr for the clearing of the inner regions of optically thick disks. After applying the same criteria to older clusters and associations (2-10?Myr) that have been observed with Spitzer, we find that the proportions of evolved and transitional disks in those populations are consistent with the measurements in Taurus when their star formation histories are properly taken into account.
The Effectiveness of Survey Recruitment Methods in Second Life

Online virtual worlds are 3D graphical environments in which users create avatars that live, work, and play-some are actual games; others are social networking sites. These worlds offer significant potential for expanding the study of social and economic behavior. One of these worlds, Second Life (SL), began in 2003 and now has more than millions of unique accounts held by virtual residents and approximately 800,000 users who log in each month. Although few results from SL surveys have been published, automated surveys are common in the virtual world. They are conducted through links to web surveys, by in-world âsurvey botsâ (programs that administer questionnaires), and through e-mail invitation to panel members recruited through SL. This article evaluates the effectiveness of recruitment techniques to complete a self-administered survey within SL. The authors tested several techniques: a billboard in an SL public space, classified ads in SL publications, paid search engine advertisements, and SL web forum posts. All survey recruits completed the same survey administered at the RTI SL facility kiosk. Our findings suggest that a diverse convenience sample can be obtained in SL at a minimal cost.