cssi/SciSciGPT-SciSciNet huggingface dataset:
The relationship between baryons and dark matter in extended galaxy halos

The relationship between gas-rich galaxies and Lyα absorbers is addressed in this paper in the context of the baryonic content of galaxy halos. Deep Arecibo H I observations are presented of two gas-rich spiral galaxies within 125 h kpc projected distance of a Lyα absorber at a similar velocity. The galaxies investigated are close to edge-on, and the absorbers lie almost along their major axes, allowing for a comparison of the Lyα absorber velocities with galactic rotation. This comparison is used to examine whether the absorbers are diffuse gas rotating with the galaxies' halos, outflow material from the galaxies, or intergalactic gas in the low-redshift cosmic web. The results indicate that if the gas resides in the galaxies' halos, it is not rotating with the system and is possibly counterrotating. In addition, simple geometry indicates that the gas was not ejected from the galaxies, and there are no gas-rich satellites detected down to 3.6-7.5 × 106 M⊙ or remnants of satellites to 5-6 × 1018 cm-2. The gas could potentially be infalling from large radii, but the velocities and distances are rather high compared to the high-velocity clouds around the Milky Way. The most likely explanation is that the galaxies and absorbers are not directly associated, despite the vicinity of the spiral galaxies to the absorbers (58-77 h kpc from the H I edge). The spiral galaxies reside in a filament of intergalactic gas, and the gas detected by the absorber has not yet come into equilibrium with the galaxy.
On the nature and origin of complexity in discrete, homogeneous, locally-interacting systems

The observed complexity of nature is often attributed to an intrinsic propensity of matter to self-organize under certain (e.g., dissipative) conditions. In order better to understand and test this vague thesis, we define complexity as “logical depth,” a notion based on algorithmic information and computational time complexity. Informally, logical depth is the number of steps in the deductive or causal path connecting a thing with its plausible origin. We then assess the effects of dissipation, noise, and spatial and other symmetries of the initial conditions and equations of motion on the asymptotic complexity-generating abilities of statistical-mechanical model systems. We concentrate on discrete, spatially-homogeneous, locally-interacting systems such as kinetic Ising models and cellular automata.
Proton life-time problem in finite grand unified theories

We study proton decay in finite supersymmetric SU(5) grand unified theories. We find that the dimension-five operators due to color triplet higgsino induce too rapid a proton decay. This behaviour can be traced to the large Yukawa couplings to the first generation that are necessary for finiteness.
Dynamics of Biofuel Stock Prices: A Bayesian Approach

We use Bayesian Markov Chain Monte Carlo methods to investigate the linkage between the volatility of ethanol security prices and the uncertainty surrounding the profitability of ethanol production and the price variations of non-ethanol energy securities. The joint evolution of return and volatility is modeled as a stochastic process that incorporates jumps in both return and volatility. While a strong and significant correlation is found between the volatility of ethanol securities and profit uncertainty from June 2005 to July 2008, the dynamic pattern of ethanol stock volatility is strikingly similar to that of the S&P 500 energy sector index in the more recent period. Our evidence lends support to the findings in the literature on rational learning from uncertainty in determining the equity price and volatility during the adoption and development of a technological innovation.
Structure, strength, and fracture of electrodeposited nickel and Ni-Co alloys

Massive electrodeposits of nickel and Ni−Co alloys ranging up to 43 pct Co were examined microstructurally and tested to determine tensile properties and static and dynamic fracture toughness. Specimens were also tested after being annealed at 575 K. Annealing increased grain size, decreased yield, and ultimate strengths, and increased ductility and dynamic toughness. The as-plated Ni-43 Co was the only material to exhibit validK IC values, averaging about 38 MN/m3/2. In instrumented dynamic tests on precracked Charpy bars, the same material exhibited aK Id of 50 MN/m3/2. The yield strength of the Ni-43 Co alloy was 1154 MN/m2. All the materials tested showed dimpled, ductile rupture fracture surfaces. The Hall-Petch behavior of the nickel indicated that it is much easier to initiate flow in normal grain boundary structures than in structures composed of dislocation cell walls.
Agency rulemaking, political influences, regulation, and industry compliance

This article empirically examines the impact of congressional oversight and agency rulemaking on firm compliance behavior in FDA-regulated industries. Congressional oversight hearings provide signals to firms about future changes in regulatory enforcement strategies. Agency rulemaking influences firms' incentives to comply with regulation because firms must invest significant resources to keep up with changing agency policy. This analysis uses three-stage least squares to simultaneously estimate both the numbers of FDA inspections and industry violators between 1972 and 1994. Results show that congressional oversight deters industry noncompliance. The effect of agency rulemaking on noncompliance differs between industries. For instance, an increasing stock of human drug rules has raised compliance among drug firms because newer more, cost-effective rules have replaced older, more costly rules. In contrast, the increasing stock of medical device rules has reduced industry compliance among device firms because these rules have increased the complexity and the scope of regulation. Copyright 1999 by Oxford University Press.
Factorization of alternating sums of Virasoro characters

G. Andrews proved that if n is a prime number then the coefficients a"k and a"k"+"n of the product (q,q)"~/(q^n,q^n)"[email protected]?"ka"kq^k have the same sign, see [G. Andrews, On a conjecture of Peter Borwein, J. Symbolic Comput. 20 (1995) 487-501]. We generalize this result in several directions. Our results are based on the observation that many products can be written as alternating sums of characters of Virasoro modules.
Analysis of Flowfields over Four-Engine DC-X Rockets

The objective of this study is to validate a computational methodology for the aerodynamic performance of an advanced conical launch vehicle configuration. The computational methodology is based on a three-dimensional, viscous flow, pressure-based computational fluid dynamics formulation. Both wind-tunnel and ascent flight-test data are used for validation. Emphasis is placed on multiple-engine power-on effects. Computational characterization of the base drag in the critical subsonic regime is the focus of the validation effort; until recently, almost no multiple-engine data existed for a conical launch vehicle configuration. Parametric studies using high-order difference schemes are performed for the cold-flow tests, whereas grid studies are conducted for the flight tests. The computed vehicle axial force coefficients, forebody, aftbody, and base surface pressures compare favorably with those of tests. The results demonstrate that with adequate grid density and proper distribution, a high-order difference scheme, finite rate afterburning kinetics to model the plume chemistry, and a suitable turbulence model to describe separated flows, plume/air mixing, and boundary layers, computational fluid dynamics is a tool that can be used to predict the low-speed aerodynamic performance for rocket design and operations.
The robotics bus: A local communications bus for robots

We address the development of a local bus architecture for robot systems that facilitates modular development, and increases the reliability of systems composed of heterogeneous sensors and actuators. The communications bus is based on Control Area Network (CAN), and supports distributed processing in physically separate nodes. Modular cabling and a modular software interface facilitate assembly and modification, and all bus communication is browseable for configuration and troubleshooting. We demonstrate two implementations of this system, and discuss its performance and capabilities compared to alternate communication architectures, with specific emphasis on mobile robots.
Kernel-Based Aggregation of Marker-Level Genetic Association Tests Involving Copy-Number Variation

Genetic association tests involving copy-number variants (CNVs) are complicated by the fact that CNVs span multiple markers at which measurements are taken. The power of an association test at a single marker is typically low, and it is desirable to pool information across the markers spanned by the CNV. However, CNV boundaries are not known in advance, and the best way to proceed with this pooling is unclear. In this article, we propose a kernel-based method for aggregation of marker-level tests and explore several aspects of its implementation. In addition, we explore some of the theoretical aspects of marker-level test aggregation, proposing a permutation-based approach that preserves the family-wise error rate of the testing procedure, while demonstrating that several simpler alternatives fail to do so. The empirical power of the approach is studied in a number of simulations constructed from real data involving a pharmacogenomic study of gemcitabine and compares favorably with several competing approaches.
Dirac fermions in a power-law–correlated random vector potential

We study localization properties of two-dimensional Dirac fermions subject to a power-law–correlated random vector potential describing, e.g., the effect of ripples in a free standing graphene. By using a variety of techniques (low-order perturbation theory, self-consistent Born approximation, replicas, and supersymmetry) we compute the low-energy density of states and discuss a possible (pre)localization of the entire single-particle spectrum.
Toward the Theory of the Supply Chain

As our discipline has matured, we have begun to develop theories of supply chain management. However, we submit that a major omission of theory development in the supply chain management discipline is that we have failed to develop a theory of what we are managing—a theory of the supply chain. Using a conceptual theory building approach, we introduce foundational premises about the structure and boundary of the supply chain, which can serve as the basis for much needed, additional development of the theory of the supply chain.
A Novel Method for the Preparation of Nucleoside Diphosphates

Sugar nucleoside diphosphates have been prepared using an efficient phosphate coupling reaction that employs a highly reactive zwitterionic phosphoramidate intermediate as the phosphorylating species.
The Cassini/Huygens Mission to Saturn

The Cassini/Huygens mission is an international cooperative effort between NASA, the European Space Agency, and the Italian Space Agency to conduct a scientific investigation of the Saturnian system. The spacecraft, which was launched in October of 1997, will use a Venus-Venus-Earth-Jupiter gravity assisted trajectory to arrive at Saturn in July of 2004. The spacecraft, composed of an orbiter and an atmospheric entry probe, will be placed in orbit about Saturn, after which the Huygens probe will be released to enter the atmosphere of Titan, the largest moon of Saturn. The probe data is transmitted during its descent and possible survival on the surface to the orbiter overhead, where it is stored and later relayed to Earth. The orbiter then continues in a four-year mission about Saturn, conducting detailed studies of the atmosphere, the rings, the magnetosphere, Titan, and the icy satellites. The probe carries six instruments to explore the atmosphere and surface of Titan; the orbiter carries twelve instruments for its investigations. This paper characterizes the performance of the Cassini/Huygens spacecraft during its first year and three-quarters of flight, up through the second of the two Venus flybys. The flight system, including the 18 scientific instruments, is described, as well as the detailed overall objectives of the mission.
X-ray study of the electric double layer at the n-hexane/nanocolloidal silica interface

The spatial structure of the transition region between an insulator and an electrolyte solution was studied with x-ray scattering. The electron-density profile across the n-hexane/silica sol interface (solutions with 5, 7, and 12 nm colloidal particles) agrees with the theory of the electrical double layer and shows separation of positive and negative charges. The interface consists of three layers, i.e., a compact layer of Na(+), a loose monolayer of nanocolloidal particles as part of a thick diffuse layer, and a low-density layer sandwiched between them. Its structure is described by a model in which the potential gradient at the interface reflects the difference in the potentials of "image forces" between the cationic Na(+) and anionic nanoparticles and the specific adsorption of surface charge. The density of water in the large electric field (approximately 10(9)-10(10) Vm) of the transition region and the layering of silica in the diffuse layer is discussed.
Synthesis of cyclopropanes by Pd-catalyzed activation of alkyl C–H bonds

Abstract A novel synthesis of cyclopropanes has been developed via palladium-catalyzed C–H activation in which two new carbon–carbon bonds are formed in a single step. This method involves palladium-catalyzed activation of normally unreactive secondary alkyl C–H bonds and provides an efficient way to access cyclopropapyrrolo[1,2- a ]indoles, analogues of mitomycin and cyclopropamitosenes.
The effect of high-frequency periodic disturbances on axisymmetric wake diffusion flames

Axisymmetric wake diffusion flame response to HF periodic velocity oscillations at combustor boundaries
Transplacental/perinatal babesiosis

in gastric tissue. McNul ty and Wise s reported that Christensen 2% urea broth had a sensitivity of 88% for diagnosing C. pyloridis in 112 patients. Morris et al. 9 have used a commercially available "Campylobacter-like organism test" to diagnose c. pyloridis infection within 24 hours, with a 96% sensitivity in 70 patients. Our study demonstrated that the Stuart urease broth is a simple, efficient, and inexpensive method for the rapid identification of C. pyloridis. It is not necessary to grind the biopsy specimen before placing it into the broth; in fact, our preliminary dat~i suggest that such grinding decreases the sensitivity of this test. An additional advantage of the Stuart broth is that the biopsy material can be removed after the testing for urease activity and cultured for C. pyloridis. There is evidence that patients with C. pyloridisassociated gastroduodenal disease represent an important subset of gastroduodenal disease that does not respond to standard therapy. Eradication of the organism and healing of the gastric lesions have been reported after treatment with a combination of antibiotics and orally administered bismuth. A rapid diagnostic test performed at endoscopy would determine the incidence of C. pyloridis gastroduodenal disease in the pediatric population, and help the physician plan immediate therapy. Thus far, definitive diagnosis of C. pyloridis-associated gastritis has required careful histologic examination of the gastric mucosa using hematoxylin and eosin stain; the microscopic visualization of the organisms is enhanced with Warthin-Starry silver stain. Stuart urease test broth allows for rapid and accurate diagnosis of C. pyloridi~ associated gastritis.
The Mormon Question: Polygamy and Constitutional Conflict in Nineteenth-Century America

My research into the “Mormon Question” has blurred disciplinary boundaries, demonstrating that legal history occurs outside the confines of law books, out in the world of popular culture, political cartooning, and sermonizing, and even in outbreaks of violence. This article is designed to illustrate how an entire body of constitutional law was made in opposition to the marital and sexual arrangements of Mormons in the Utah Territory in the nineteenth century.
Asymmetric synthesis of (+)-loline, a pyrrolizidine alkaloid from rye grass and tall fescue

(+)-Loline (1) was synthesized via a pathway that employed intramolecular [4 + 2] cycloaddition of an acylnitrosodiene, 25 or 26, as a key step. The acylnitrosodienes, which were used in situ, were obtained by oxidation of the corresponding hydroxamic acids, 17 and 24, and these were prepared from either glucose via aldehyde 9 or more directly from (S)-malic acid (18). The endo dihydrooxazines 27 and 29, obtained in a mixture with their exo stereoisomer, were transformed by reductive N–O bond cleavage and reannulation into pyrrolizines 34 and 35. The latter was subjected to Sharpless aminohydroxylation in the presence of (DHQD)2PHAL to give 50 along with its regioisomer 51. N-Methylation of tosyl amide 50, followed by mesylation of alcohol 52 and reduction of the γ-lactam 53 with borane, afforded pyrrolizidine 54. Cleavage of the p-methoxybenzyl ether and subsequent thermal treatment of 55 resulted in intramolecular etherification to yield N-tosylloline (57). Final reductive cleavage of the N-tosyl residue produced (+)-loline, characterized as its dihydrochloride.
Acute pain at discharge from hospitalization is a prospective predictor of long-term suicidal ideation after burn injury

Abstract Edwards RR, Magyar-Russell G, Thombs B, Smith MT, Holavanahalli RK, Patterson DR, Blakeney P, Lezotte DC, Haythornthwaite JA, Fauerbach JA. Acute pain at discharge from hospitalization is a prospective predictor of long-term suicidal ideation after burn injury. Objective To determine the extent to which pain contributes to risk for suicidal ideation after burn injury. Design This longitudinal cohort study evaluated participants at discharge, 6 months, and 1 year after burn injury. Setting Inpatient rehabilitation units of multiple regional burn centers. Participants Survivors of major burns (N=128). Interventions Not applicable. Main Outcome Measures Pain severity, assessed using the Medical Outcomes Study 36-Item Short-Form Health Survey bodily pain subscale, and passive and active suicidal ideation, assessed by self-report. Results At each time point, approximately one quarter to one third of the sample reported some form of suicidal ideation. In logistic regression analyses, pain severity at discharge was the sole consistent predictor of suicidal ideation at follow-up, with greater pain severity being associated with enhanced risk for both passive and active suicidal ideation. These associations were observed even after controlling for discharge mental health. Conclusions These are the first findings to suggest an association between acute pain severity and the development and maintenance of suicidal ideation in burn patients. Further research in this area, including the study of improved pain management programs as a prophylaxis against suicidal ideation, may benefit those who are at elevated suicide risk as a consequence of burn injuries.
HRM: A Management Science in Need of Discipline*

Human resource management (HRM), as a subdiscipline of management science, is in its infancy. HRMpractices are often utopian in expectation and fail to incorporate a realistic view of existing knowledge bases in the psychological, social, and biological sciences. The HRM discipline relies upon theoretical approaches (e.g., theories of motivation, satisfaction, and performance) which are: 1) almost invariably linear in conceptualization and depend largely upon correlational evidence, 2) frequently validated within non-representative contexts that are overly constrained by researchers, and 3) overly simplistic in that the constraints and patterns imposed by our biological, psychological, and social systems are frequently ignored or assumed to constitute random error within the models. This frequently translates into HRM practices which map reasonably well onto theory yet fall short of yielding expected outcomes. The theories do not match the realties observed. We point to non-linear dynamics and chaos theory as a way of conceptualizing how common HRM practices may translate into observable outcomes. Such an approach will force managers to pull back from simple reliance on linear predictions and realize that truly effective HRM practices should be sensitive to the unique, complex, and less systematically predictable patterns of human behaviour.
Kinematics of the Hercules Supercluster

?????The Hercules supercluster consists of the Abell clusters A2147, A2151, and A2152. Previous studies of the kinematics have been confounded by the difficulty of correctly assigning galaxies to the individual clusters, which are not well separated. Our study has a total of 468 available velocities for galaxies in the region, 175 of them new. There are 414 galaxies in the supercluster, about 3 times the number used in the previous supercluster study. We verify the existence of the three individual clusters and compute their individual dynamical parameters. We investigate several techniques for assigning galaxy membership to clusters in this crowded field. We use the KMM mixture-modeling algorithm to separate the galaxies into clusters; we find that A2152 has a higher mean velocity than previous studies have reported. A2147 and A2152 also have lower velocity dispersions: 821 and 715 km s-1, respectively. The assignment of galaxies to either A2152 or A2147 requires velocity and position information. We study the kinematics of the supercluster using the two-body formalism of Beers, Geller, & Huchra and conclude that A2147 and A2151 are probably bound to each other and that the supercluster as a whole may also be bound. The mass of the supercluster, if bound, is (7.6 ? 2.0) ? 1015 h-1 M?; with the supercluster luminosity, (1.4 ? 0.2) ? 1013 h-2 L?, this yields ? ? 0.34 ? 0.1.
Protein microarrays for genome-wide posttranslational modification analysis

Protein microarray technology has emerged as a powerful tool for comparing binding interactions, expression level, substrate specificities, and posttranslational modifications (PTMs) of different proteins in a parallel and high-throughput manner. The ability to immobilize proteins to a solid surface and register the specific address of each protein has bridged major limitations for investigating the proteome in biological samples, namely, the wide dynamic range of protein concentrations and the perturbation of the physical and chemical properties of proteins by their modification. Recent advances introduced the use of functional mammalian cell extracts to assay PTMs under different cellular conditions. This assay offers a new approach for performing large-scale complex biochemical analysis of protein modifications. Here, we review studies of PTM profiling using protein microarrays and discuss the limitations and potential applications of the system. We believe that the information generated from such proteomic studies may be of significant value in our elucidation of the molecular mechanisms that govern human physiology.
On the integral systems related to Hardy-Littlewood-Sobolev inequality

We prove all the maximizers of the sharp Hardy-Littlewood-Sobolev inequality are smooth. More generally, we show all the nonnegative critical functions are smooth, radial with respect to some points and strictly decreasing in the radial direction. In particular, we resolve all the cases left open by previous works of Chen, Li and Ou on the corresponding integral systems.
Catalytic enantioselective allenylation reactions of aldehydes with tethered bis(8-quinolinolato) (TBOx) chromium complex.

The utility of the new class of chiral ligand, tethered bis(8-quinolinol) (TBOxH), is further explored. Its chromium complex, TBOxCr(III)Cl, effectively catalyzes the asymmetric allenylation reactions of various aldehydes at room temperature with high yields (up to 91%) and high enantioselectivities (up to 97% ee). The scope of the present method is shown to be wide, and this method represents an efficient access to chiral α-allenic alcohols.
A minimum entropy principle of high order schemes for gas dynamics equations

The entropy solutions of the compressible Euler equations satisfy a minimum principle for the specific entropy (Tadmor in Appl Numer Math 2:211–219, 1986). First order schemes such as Godunov-type and Lax-Friedrichs schemes and the second order kinetic schemes (Khobalatte and Perthame in Math Comput 62:119–131, 1994) also satisfy a discrete minimum entropy principle. In this paper, we show an extension of the positivity-preserving high order schemes for the compressible Euler equations in Zhang and Shu (J Comput Phys 229:8918–8934, 2010) and Zhang et al. (J Scientific Comput, in press), to enforce the minimum entropy principle for high order finite volume and discontinuous Galerkin (DG) schemes.
General analysis of B decays to two pseudoscalars for EWP, rescattering and color suppression effects

Abstract A general analysis for B decays to two pseudoscalars, involving ten modes, is presented. A simple model for final state interactions and rescattering effects is proposed. We show how the data can be used to deduce important information on electroweak penguins (EWP), rescattering and color suppression effects and on the CKM parameters in a largely model independent way by using χ 2 -minimization. We find that the current data suggests the presence of color-suppressed tree at levels somewhat larger than simple theoretical estimates. Once the data improves the extraction of α and/or γ may become feasible with this method as we illustrate with the existing data.
Signaling With Imperfect Channel State Information: A Battery Power Efficiency Comparison

Due to complexity considerations, pulse-based modulations such as pulse position modulation (PPM) and on-off keying (OOK) are well suited for wireless sensor networks (WSNs) since they provide the possibility of carrier-less signaling and, more importantly, noncoherent reception bypassing channel estimation at the receiver. In this paper, we compare PPM and OOK in terms of their battery power efficiencies, using a nonlinear battery model, and under the same bandwidth occupancy, bandwidth efficiency and cutoff rate requirement. Cutoff rate is used as our comparison criterion because it leads to a tractable analysis that is often impossible through direct evaluation of random coding exponent or capacity. In addition, cutoff rate gives a universal expression for both coherent and noncoherent detection by simply setting various channel state information (CSI) qualities. Our system model integrates typical WSN transmission and reception modules with realistic nonlinear battery models. Circuit power consumption, dc-dc converter efficiency, and power amplifier efficiency are also taken into consideration. Our analytical results characterize the signal-to-noise ratio (SNR)-cutoff rate-CSI region where PPM is more power efficient than OOK, and vice versa. We provide an interpretation in terms of the transmission range and symbol set size. Numerical results are also provided to verify the analysis.
Skewed shear-layer mixing within a duct

In the experiments highlighted here, incompressible skewed shear-layer mixing is studied. The mixing region is confined in the sense that the streams impinge somewhat on the side walls of the duct into which the two streams flow. Generally there are differences in the two streams'relative speeds in both the streamwise and spanwise directions, and therefore fluxes of two vorticity components separate from the splitter plate. The mass flow ratio is varied for a fixed amount of skewing, and mixing development within the duct is investigated.
Inside the critical window for cohomology of random k‐complexes

We prove sharper versions of theorems of Linial–Meshulam and Meshulam–Wallach which describe the behavior for -cohomology of a random k-dimensional simplicial complex within a narrow transition window. In particular, we show that if Y is a random k-dimensional simplicial complex with each k-simplex appearing i.i.d. with probability with and fixed, then the dimension of cohomology is asymptotically Poisson distributed with mean . In the k = 2 case we also prove that in an accompanying growth process, with high probability, vanishes exactly at the moment when the last -simplex gets covered by a k-simplex, a higher-dimensional analogue of a “stopping time” theorem about connectivity of random graphs due to Bollobas and Thomason. Random Struct. Alg., 2015
Three-dimensional small-signal analysis of a free electron laser

Abstract We present a three-dimensional analysis of the cw free electron laser amplifier in the small-signal domain. The formalism is used to derive expressions for the power gain in both small-gain (perturbative) and large-gain (non-perturbative) situations, and differences from the corresponding formulas of the one-dimensional theory are studied in detail. In the small-gain case diffraction causes a lowering of the frequency of maximum gain and a distortion in the shape of the gain profile relative to the one-dimensional results. In the large gain case the primary effect of diffraction of wave fields is to shift the effective resonance frequency and the overall phase locally at each space point by amounts that depend on the radial distance of the point from the beam axis. This leads to the results that a resonant optical beam amplifying in the electron-wiggler system undergoes a small diffractive spreading than what it would have in free space, whereas off-resonant or broard-bandwidth pulsed beams may experience transverse spatial instabilities.
Optimal nonlinear income taxation with a finite population

Abstract In the standard optimal income taxation problem, tax payments depend only on each consumer's own actions. Piketty [J. Econ. Theory 61 (1993) 23–41] shows that, if one individual's tax schedule depends on others’ actions and the government knows the exact ability distribution, it can implement any undistorted allocation as the unique revelation game outcome. If some individuals misreveal their types, Piketty's mechanism may assign infeasible allocations. We require that tax schedules must balance the government budget for every possible vector of revelations. When individuals reveal their type by simple announcements, all undistorted allocations can be still implemented, even with off-equilibrium feasibility constraints.
Verification of TG-61 dose for synchrotron-produced monochromatic x-ray beams using fluence-normalized MCNP5 calculations.

Purpose: Ion chamber dosimetry is being used to calibrate dose for cell irradiations designed to investigate photoactivated Auger electron therapy at the Louisiana State University Center for Advanced Microstructures and Devices (CAMD) synchrotron facility. This study performed a dosimetry intercomparison for synchrotron-produced monochromatic x-ray beams at 25 and 35 keV. Ion chamber depth-dose measurements in a polymethylmethacrylate (PMMA) phantom were compared with the product of MCNP5 Monte Carlo calculations of dose per fluence and measured incident fluence. Methods: Monochromatic beams of 25 and 35 keV were generated on the tomography beamline at CAMD. A cylindrical, air-equivalent ion chamber was used to measure the ionization created in a 10 Multiplication-Sign 10 Multiplication-Sign 10-cm{sup 3} PMMA phantom for depths from 0.6 to 7.7 cm. The American Association of Physicists in Medicine TG-61 protocol was applied to convert measured ionization into dose. Photon fluence was determined using a NaI detector to make scattering measurements of the beam from a thin polyethylene target at angles 30 Degree-Sign -60 Degree-Sign . Differential Compton and Rayleigh scattering cross sections obtained from xraylib, an ANSI C library for x-ray-matter interactions, were applied to derive the incident fluence. MCNP5 simulations of the irradiation geometry provided the dose depositionmore » per photon fluence as a function of depth in the phantom. Results: At 25 keV the fluence-normalized MCNP5 dose overestimated the ion-chamber measured dose by an average of 7.2 {+-} 3.0%-2.1 {+-} 3.0% for PMMA depths from 0.6 to 7.7 cm, respectively. At 35 keV the fluence-normalized MCNP5 dose underestimated the ion-chamber measured dose by an average of 1.0 {+-} 3.4%-2.5 {+-} 3.4%, respectively. Conclusions: These results showed that TG-61 ion chamber dosimetry, used to calibrate dose output for cell irradiations, agreed with fluence-normalized MCNP5 calculations to within approximately 7% and 3% at 25 and 35 keV, respectively.« less
Towards constraining Affleck-Dine baryogenesis

Affleck-Dine baryogenesis is preconditioned on a certain structure of nonrenormalizable operators in the Kahler potential. In this paper, we geometrically characterize the resulting constraint on the field space Kahler geometry and survey the Lagrangian for correlated predictions. The Affleck-Dine field backreacts on the inflaton, and by mapping the backreacted potential to an inflaton potential with a step, we find that current CMB data severely constrain some versions of the scenario.
Tax incidence in Madagascar : an analysis using household data

This article discusses tax incidence in Madagascar and asks who pays the taxes that finance government spending. Its main concern is to identify the progressivity of different taxes levied in Madagascar, based on the consumption and income patterns found in the 1994 Enquete Permanente aupres des Menages, a nationally representative survey. The results suggest that most taxes are progressive, meaning that wealthy households pay proportionately more of these taxes relative to their expenditures than do poor households. Two notable exceptions are taxes on kerosene and export duties on vanilla, both of which are regressive. These results are consistent with those of a study of Ghana, the only other comparable research on tax incidence in Africa. That study found taxes on kerosene and cocoa exports to be the most regressive taxes in Ghana. Making firm policy recommendations for tax reform would require an analysis of the economic efficiency and administrative efficacy of different taxes to complement this article's work on their equity implications. Nevertheless, the results suggest that the movement away from trade taxes, especially export duties, and toward broadly based value added or income taxes would be more equitable and more economically efficient. The only legitimate impediment to such reforms in Madagascar is administrative, that is, the government's ability to collect different taxes effectively. Although administrative efficiency may be a problem for value added or income taxes, taxes on petroleum products (except kerosene) are highly progressive and provide a good tax handle.
Campaign Spending in Proportional Electoral Systems: Incumbents Versus Challengers Revisited

This article (a) argues that campaign spending is no more effective for challengers than incumbents in congressional elections using candidate-centered forms of proportional representation (PR), (b...
Has ECOWAS Promoted Trade among Its Members

This paper reports the results of an examination of the direction of trade within the Economic Community of West African States (ECOWAS). The examination was conducted in order to determine whether ECOWAS is effective in enlarging trade among its members. Such an effect would indicate that the type of integration efforts that promote trade among industrial countries may also be applicable in less-developed regions. The paper provides an overview of ECOWAS and contains a description of recent directional trade patterns within the region using the trade intensity index (TII). That measure, in turn, is analysed using a spatial interaction model specified as a tobit regression. Our measure of TII indicates that trade flows within the region are strong when considered on a relative basis. However, a comparison of recent trade flows to earlier ones indicates that a very similar pattern of trade flows existed before ECOWAS was formed. Our primary finding, therefore, is that ECOWAS has not been effective in promoting trade among its members. Copyright 1998 by Oxford University Press.
Lamb Wave Tomography and Its Application in Pipe Erosion/Corrosion Monitoring

Abstract Ultrasonic Lamb wave techniques are widely used in a number of NDE applications. To excite Lamb waves, mode conversion of bulk waves or photoacoustic excitation often are used. Both of these approaches suffer from the need for liquid couplant or ablation of materials to reach a good signal-to-noise ratio. In this paper, we propose a novel technique that utilizes point source excitation and detection of Lamb waves through dry, elastic contacts to monitor velocity changes. A pair of pin transducers is used to excite and detect the A 0 mode Lamb wave in the pipe wall, and the wave velocity is obtained by time-of-flight measurement. Any change in the pipe wall thickness can be detected by the change in the Lamb wave velocity due to the dispersive nature of the A 0 mode. We demonstrate the power of this approach in ultrasonic pipe erosion/corrosion monitoring and its potential application in aircraft skin defect imaging. We present results of measurements of plate thickness and erosion/corrosion in a ...
Incorporation of strontium into reef coral skeletal carbonate

Abstract Two thousand and twenty well-characterized coral specimens from 17 localities have been analyzed for Sr. Seventy-three genera and subgenera, mostly hermatypic scleractinians, are represented. For some genera, specimens living in surface reef environments are compared with those from 18.3 m depths on the same reefs. Growth rates for some species have also been measured at these depths at one of the sampling sites. Skeletal strontium for a given genus decreases with increasing water temperature, a relationship which previously eluded detection. Aragonite deposited by corals living on the reef at a depth of 18.3 m contains more strontium than the skeletal aragonite of the same coral genera from shallow-water, surface environments. Quantitative treatment of the data for Acropora, one of the most abundant and widely distributed of the reef-building corals, suggests that the observed strontium variations may reflect variations in the rate of skeletal calcification, rather than direct dependence upon temperature or water depth. There is evidence for ‘species effects’, apparently unrelated to growth rate differences, in that certain coral genera are consistently enriched or depleted in skeletal strontium content relative to other genera living in the same reef environments under identical ambient conditions. Temperature, salinity, water depth, seawater composition, and/or other such parameters may in part determine the levels of trace element concentration in carbonates deposited by corals and other marine invertebrates, but it would appear that these variables more directly affect physiological processes which in turn control skeletal chemistry.
Do early and voluntary filers of financial information in XBRL format signal superior corporate governance and operating performance

On March 16, 2005, the SEC issued Final Rule 33-8529 encouraging registrants to voluntarily file tagged financial statement information on the EDGAR reporting System using XBRL format. In this paper, we examine whether early and voluntary filers of financial information in XBRL format demonstrate superior corporate governance and operating performance relative to their non-adopting peers. We investigate performance, market, and structure-related firm variables. Our results suggest that corporate governance is significantly and positively associated with a firm's decision to be an early and voluntary filer of financial information in XBRL format. At the same time, firm performance factors including liquidity and firm size are also associated with the early and voluntary XBRL filing decision. Our findings should be particularly interesting for the SEC, as it considers the corporate governance and firm-performance related associations between certain registrants' early and voluntary response and its call for XBRL-based filings.
Comment: Quantifying Information Loss in Survival Studies

In their paper, Nicolae, Meng, and Kong (henceforth NMK) propose several very interesting methods for quantifying the fraction of missing information in a sample, and focus their attention on genetic studies. Survival analysis is another area in Statistics where missing information plays an important role. Here, censoring complicates study design, for example when we want to determine how big a clinical trial should be in order to have a good chance of detecting a treatment effect in a Cox model. Most current methods for dealing with this difficult problem involve two stages, where in the first stage we make a projection of what the variance of the coefficient of the treatment effect would be if there was no censoring, and in the second stage we make a correction to adjust for the censoring. Often this is done under restrictive parametric (e.g. exponential) assumptions for the underlying distributions. It would be desirable to use the methods proposed by NMK in the survival analysis setting. I tried to carry over their methods to the Cox model, and encountered some problems. The difficulties I discovered led me to consider modifications of their proposals, which I believe work well. Below I discuss the setup I consider, my experiences, the issues, and some approaches I think are promising.
Birth Weight Among Women of Different Ethnic Groups

Differences in mean birth weight and low birth weight (less than 2.5 kg) are analyzed among Asians, blacks, Hispanics, and whites who were enrolled in the Northern California Kaiser-Permanente Birth Defects Study, a prospective study of 29,415 pregnancy outcomes. Large differences in birth weight among babies of different ethnic groups persist after controlling for the joint effects of maternal smoking and alcohol use during pregnancy, sex of child, parity, length of prenatal care, and maternal weight-for-height percentile. Compared with whites, the relative mean differences in birth weight are estimated as -246 g for blacks, -210 g for Asians, -105 g for Hispanics, and -140 g for others. The low-birth-weight rates and crude odds ratios are 7.70% (2.17) for blacks; 5.57% (1.57) for Asians; 5.52% (1.55) for others; 4.00% (1.13) for Hispanics; and 3.55% (1.00) for whites. After controlling for the effects of 22 factors, the odds ratios for a low-birth-weight infant are 2.41 for blacks, 1.37 for Asians, 1.93 for others, and 1.25 for Hispanics. It is concluded that factors currently used to control for ethnic differences in birth weight are insufficient to explain the observed differences.
Synthesis of 7-membered cyclic oxamides: Novel HIV-1 protease inhibitors

Abstract An intermediate with three chiral centers, constructed by two key reactions viz. asymmetric allylboration and Sharpless epoxidation, has been used for the synthesis of novel 7-membered cyclic oxamides.
The Mass Distribution of SDSS J1004$+$4112 Revisited

We present a strong lens analysis of SDSS J1004+4112, a unique quasar lens produced by a massive cluster of galaxies at z = 0.68, using newly developed software for gravitational lensing. We find that our parametric mass model well reproduces all observations, including the positions of quasar images as well as those of multiply imaged galaxies with measured spectroscopic redshifts, time delays between quasar images, and the positions of faint central images. The predicted large total magnification of � � 70 suggests that the lens system is indeed a useful site for studying the fine structure of a distant quasar and its host galaxy. The dark halo component is found to be unimodal, centered on the brightest cluster galaxy and the Chandra X-ray surface brightness profile. In addition, the orientation of the halo component is quite consistent with those of the brightest cluster galaxy and member galaxy distribution, implying that the lensing cluster is a relaxed system. The radial profile of the best-fit mass model is in good agreement with a mass profile inferred from the X-ray observation. While the inner radial slope of the dark halo component is consistent with being � 1, a clear dependence of the predicted A–D time delay on the slope indicates that an additional time-delay measurement will improve constraints on the mass model.
Duopoly information equilibrium: Cournot and bertrand

Abstract In a duopoly model where firms have private information about an uncertain linear demand, it is shown that if the goods are substitutes (not) to share information is a dominant strategy for each firm in Bertrand (Cournot) competition. If the goods are complements the result is reversed. Furthermore the following welfare results are obtained: 1. (i) With substitutes in Cournot competition the market outcome is never optimal with respect to information sharing but it may be optimal in Bertrand competition if the products are good substitutes. With complements the market outcome is always optimal. 2. (ii) Bertrand competition is more efficient than Cournot competition. 3. (iii) The private value of information to the firms is always positive but the social value of information is positive in Cournot and negative in Bertrand competition.
A 2D Barcode Validation System for Mobile Commerce

The wide deployment of wireless networks and mobile technologies and the significant increase in the number of mobile device users has created a very strong demand for emerging mobile commerce applications and services. Barcode-based identification and validation solutions are considered an important part of electronic commerce systems, particularly in electronic supply chain systems. This paper reports a mobile-based 2D barcode validation system as part of mobile commerce systems. This barcode-based validation solution is developed based on the Data Matrix 2D-Barcode standard to support barcode-based validation in mobile commerce systems on mobile devices. The paper demonstrates its application by building a mobile movie ticketing system.
Magnetotransport properties of thin C–Fe films

Abstract The magnetotransport properties of C–Fe films formed by e-beam vapor deposition onto glass substrates are presented in the temperature region of 2 K to 300 K. Hall effect measurements reveal a significant anomalous Hall voltage whose magnitude increases with increasing temperature. Measurements of the ordinary Hall coefficient in 10 nm-thick films reveal a charge carrier density ranging from n ≅ 3.0 × 1029 m−3 at 2 K to approximately half that value at 290 K. A comparison between anomalous Hall effect and parallel field magneto-optic Kerr effect measurements reveals a highly anisotropic coercive field with the easy direction lying in the plane of the film. Magnetoresistance measurements show that the films posses isotropic linear positive magnetoresistance beyond their saturation magnetization. The presence of carbon nanotubes formed during the e-beam process is confirmed via atomic force microscopy.
Did Hayek and Robbins Deepen the Great Depression

Contrary to some accounts, the Hayek-Robbins (“Austrian”) theory of the business cycle did not prescribe a monetary policy of “liquidationism” in the sense of passive indifference to sharp deflation during the early years of the Great Depression. There is no evidence that Hayek or Robbins influenced any “liquidationist” in the Hoover administration or the Federal Reserve System. Federal Reserve policy during the Great Depression was instead influenced by the real bills doctrine, which (despite some apparent similarities) was diametrically opposed in key respects to Hayek’s norms for central bank policy.
Effects of Diet on Urinary Bladder Carcinogenesis and Cancer Prevention

Urine plays a major role in bladder carcinogenesis, acting as a transport mechanism for carcinogens, containing several growth factors stimulating cell proliferation, and indirectly affecting chemicals by alterations in concentrations of normal urinary components such as electrolytes, water and proteins. These latter effects are greatly modified by diet composition and consumption and also by water consumption. Several examples of these effects are presented.