cssi/SciSciGPT-SciSciNet huggingface dataset:
Carbon multi-walled nanotubes grown by HWCVD on a pyroelectric detector

Abstract Carbon multi-wall nanotubes (MWNTs) were grown on a lithium niobate (LiNbO3) pyroelectric detector with a nickel film as the catalyst by hot-wire chemical vapor deposition (HWCVD). Two detectors are documented, each with slightly different deposition conditions. The absolute spectral responsivity of each device was measured from 600 nm to 1800 nm and indicates that the MWNT-coating absorptance is spectrally uniform, with variations of only a few percent. We also discuss growth of MWNTs on LiTaO3 by CVD and the limitations presented by the Curie temperature of the pyroelectric material.
Integrated planning and execution for autonomous spacecraft

An autonomous spacecraft must balance long-term and short-term considerations. It must perform purposeful activities that ensure long-term science and engineering goals are achieved and ensure that it maintains positive resource margins. This requires planning in advance to avoid a series of shortsighted decisions that can lead to failure. However, it must also respond in a timely fashion to a somewhat dynamic and unpredictable environment. Thus, in terms of high-level, goal-oriented activity, spacecraft plans must often be modified due to fortuitous events such as early completion of observations and setbacks such as failure to acquire a guidestar for a science observation. This describes an integrated planning and execution architecture that supports continuous modification and updating of a current working plan in light of a changing operating context.
Characterization of surface structure in heterogeneous catalysts by high-resolution transmission electron microscopy

Abstract Model catalysts consisting of an active phase dispersed on nonporous oxide particles of submicron size with simple. geometric shapes are described. These model catalysts provide information about surface structure from the dispersed phase in heterogeneous catalysts. Morever, surface structure can be correlated with measurements of catalytic activity from the same catalyst and thereby provide better understanding of the working catalyst surface and the interaction of the active phase with the support. The use of model supports permits direct visualization of oxide dissolution and restructuring that occurs in Al 2 O 3 , TiO 2 and MgO supports when acidic precursors are used. Electron microscopic examination reveals differences in the crystal structure of Rh particles that explain how the support influences the oxidation and reduction behavior of the metal. Edge-on views demonstrate that the metal oxide formed after oxidation of the metal remains three-dimensional in shape and does not spread on the silica support.
Investigation of moving-bank multiple model adaptive algorithms

The feasibility of a moving-bank multiple model adaptive estimator/controller is examined. Compared to a conventional full-bank multiple model adaptive algorithm, a significant reduction in the number of required elemental filters is accomplished through a dynamic re-declaration of the positions in parameter space that the elemental filters occupy. Critical to the performance of the moving-bank estimator is the decision method that governs movement of the bank of elemental filters. Five such methods are developed and their performances are compared to each other and to a benchmark filter with artificial knowledge of the "true" parameter value. Three adaptive controller algorithms are also generated and evaluated. A simple but physically motivated example is used to gain insights into relative performance potential of the proposed algorithms.
Doping Dependence of Thermal Oxidation on n-Type 4H-SiC

The doping dependence of dry thermal oxidation rates in n-type 4H-SiC was investigated. The oxidation was performed in the temperature range of 1000 °C to 1200 °C for samples with nitrogen doping in the range of 6.5 × 1015 to 9.3 × 1018/cm3, showing a clear doping dependence. Samples with higher doping concentrations displayed higher oxidation rates. The results were interpreted using a modified Deal-Grove model. Linear and parabolic rate constants and activation energies were extracted. Increasing nitrogen led to an increase in the linear-rate-constant preexponential factor from 10-6 to 10-2 m/s and the parabolic-rate-constant preexponential factor from 10-9 to 10-6 m2/s. The increase in the linear rate constant was attributed to defects from doping-induced lattice mismatch, which tend to be more reactive than bulk crystal regions. The increase in the diffusion-limited parabolic rate constant was attributed to the degradation in the oxide quality originating from the doping-induced lattice mismatch. This degradation was confirmed by the observation of a decrease in the optical density of the grown oxide films from 1.4 to 1.24. The linear activation energy varied from 1.6 to 2.8 eV, while the parabolic activation energy varied from 2.7 to 3.3 eV, increasing with doping concentration. These increased activation energies were attributed to the higher nitrogen content, leading to an increase in the effective bond energy stemming from the difference in C-Si (2.82 eV) and Si-N (4.26 eV) binding energies. This paper provides crucial information in the engineering of SiO2 dielectrics for SiC metal-oxide-semiconductor structures, which typically involve regions of very different doping concentrations, and suggests that thermal oxidation at high doping concentrations in SiC may be defect mediated.
Seismic and geodetic constraints on Cascadia slow slip

[1] Automatically detected and located tremor epicenters from episodic tremor and slip (ETS) episodes in northern Cascadia provide a high-resolution map of Washington's slow slip region. Thousands of epicenters from the past four ETS events from 2004 to 2008 provide detailed map-view constraints that correlate with geodetic estimates of the simultaneous slow slip. Each of these ETS events exhibits remarkable similarity in the timing and geographic distribution of tremor density and geodetically inferred slip. Analysis of the latest 15-month inter-ETS period also reveals ageodetic tremor activity similar both in duration and extent to ETS tremor. Epicenters from both ETS and inter-ETS tremor are bounded between the 30- and 45-km plate interface depth contours and locate approximately 75 km east of previous estimates of the locked portion of the subducting Juan de Fuca plate. Inter-ETS tremor overlaps but is generally downdip of ETS tremor and does not yet correlate with geodetically observed slip, but this is likely because the slip is below current GPS detection levels. Based on the tremor and slip correlation and the tremor-duration and slip magnitude relationship, we suggest that the well-resolved, sharp updip edge of tremor epicenters reflects a change in plate interface coupling properties. The region updip of this boundary may accumulate stress with the potential for coseismic shear failure during a megathrust earthquake. Alternatively, plate convergence in this region could be accommodated by continuous slow slip with no detectable tremor or by slow slip events with sufficiently long recurrence intervals that none have been detected during the past 10 years of GPS observations.
d-wave pairing symmetry in cuprate superconductors

Abstract Phase-sensitive tests of pairing symmetry have provided strong evidence for predominantly d-wave pairing symmetry in both the hole- and electron-doped high-Tc cuprate superconductors. Temperature dependent measurements in YBa2Cu3O7-σ (YBCO) indicate that the d-wave pairing dominates, with little if any imaginary component, at all temperatures from 0.5K through Tc. In this article we review some of this evidence and discuss the implications of the universal d-wave pairing symmetry in the cuprates.
Three-flavor analysis of long-baseline experiments

We compare the analysis of existing and future neutrino oscillation long-baseline experiments, where we point out that the analysis of future experiments actually implies a 12-dimensional parameter space. Within the three-flavor neutrino oscillation framework, six of these parameters are the fit parameters, and six are the simulated parameters. This high-dimensional parameter space requires the condensation of information and the definition of performance indicators for the purpose needed. As the most sophisticated example for such an indicator, we choose the precision of the leptonic CP phase, and discuss some of the complications of its computation and interpretation.
Instability of Near-Extremal Black Holes in N=2, d=4 Supergravity

As a precursor to studying the bound states of multiple non-extremal black holes in $ \mathcal{N}=2 $ , d = 4 supergravity, we investigate the stability of a near-extremal D0-D4 black hole in the probe limit, when the parameters of the black hole solution lie within a certain regime. We determine whether it is possible to form bound states of this “core” non-extremal black hole with BPS probe particles, and whether it is possible for the “core” black hole to decay by the emission of such BPS probes either to a local minimum of the probe potential, or spatial infinity. We first carry out a qualitative analysis of the probe potential to determine when quantum tunneling of probes from the black hole is possible. We then find the wavefunction of the scattered probe by using the WKB approximation to solve the Dirac equation in the black hole background, and use this solution to compute the tunneling amplitude.
Dual expansions of N=4 super Yang–Mills theory via IIB superstring theory

Abstract We examine the dual correspondence between holographic IIB superstring theory and N =4 super Yang–Mills theory at finite values of the coupling constants. In particular we analyze a field theory strong-coupling expansion which is the S-dual of the planar expansion. This expansion arises naturally as the AdS/CFT dual of the IIB superstring scattering amplitudes given a genus truncation property due to modular invariance. The space–time structure of the contributions to the field theory four-point correlation functions obtained from the IIB scattering elements is investigated in the example of the product of four conserved stress tensors, and is expressed as an infinite sum of field theory triangle integrals. The OPE structure of these contributions to the stress tensor four-point function is analyzed and shown not to give rise to any poles. Quantization of the string in the background of a five-form field strength is performed through a covariantized background field approach, and relations to the N =4 topological string are found.
Prospects for Far Infrared Arrays

We report initial performance measurements of a 1/8 scale version of a 32x32 pixel array under development for SIRTF. This array demonstrates that we can reach the sensitivity limits set by the natural backgrounds in space while providing good imaging and photometric performance. Based on the achieved performance levels, we project the imaging capabilities of SIRTF in the far infrared to exceed by a factor of more than 10,000 those achieved by any preceding telescope.
Synthesis of Typical Environments

Envirornmental synthesis is defined as a procedure by which an electromagnetic enviromnent (including equipment types, numbers and deployments) is generated, based on partial information. There is a need for such syntheses since complete information in both current and future time periods will never be available. Another requirement arises when excessive computer time is a significant factor. Since environmental synthesis implies relatively coarse inputs and outputs, its use should be confined to those areas in which such outputs are justified. Two such areas include frequency allocation and equipment specifications, both of which involve future installations, whose location and time frame are not known precisely. Answers are required which will indicate, in general terms, whether an equipment will cause or experience harmful degradation due to unintentional interference. One type of answer, termed separation criteria, can indicate the minimum geographical spacing and/or frequency separation which will be necessary to permit two specific equipments (or equipment types) to operate in a compatible manner. There is a choice of sampling all possible environments or generating a series of typical environments. The latter approach seems more practical, economic, and meaningful. For, if a system can perform satisfactorily in a "worst case" enviromnent, it will certainly operate in less congested situations. If it does not pass the worst case test, significant problem areas can be identified and a reasonable lower bound imposed. A number of statistical distributions are described, involving deployment of equipments, propagation effects, operating frequency, and antenna gain characteristics.
Psychotropic drug therapy in children and adolescents

Abstract The author reviews the current indications and dosages of psychotropic medications for children. As part of an overall therapeutic program, various psychotropic drugs may be useful to varying degrees for attention deficit disorder, pervasive developmental disorders and schizophrenic disorders, Tourette's disorder, major depressive disorder, functional enuresis, separation anxiety, and bipolar affective disorder. The limited nature of the literature on drug treatment of some of these disorders is stressed, as is the need to balance benefits against potential side-effects.
An Improved Procedure for the Synthesis of Chiral 2-Aza-Bicyclo[2.2.1]heptane

Abstract Grieco's protocol for the synthesis of 2-aza-bicyclo[2.2.1]heptane is modified and adapted for large scale preparation. The optical purity of the material is readily upgraded by purification through a chiral salt.
Instability of the E-F coupled nighttime midlatitude ionosphere

[1] Tsunoda and Cosgrove [2001] recently pointed out that the F layer and sporadic E (Es) layers in the nighttime midlatitude ionosphere must be considered electrodynamically as a coupled system in light of the presence of a Hall polarization process in Es layers [Haldoupis et al., 1996; Tsunoda, 1998; Cosgrove and Tsunoda, 2001, 2002a] and the fact that kilometer-scale electric fields map efficiently between the E and F regions. They further noted the apparent presence of positive feedback between processes in those regions. Cosgrove and Tsunoda [2002b, 2003] have since shown that Es layers are unstable with properties not unlike those of the Perkins instability in the F region [Perkins, 1973], thus providing yet another reason to consider the behavior of the coupled system. In this paper we show mathematically that the coupled system is indeed unstable with properties that are not only related to but distinct from those of the individual instabilities. A key finding is that this coupled response significantly enhances the growth rate of F region structures, beyond that of the Perkins instability.
Meson decay constants from the valence approximation to lattice QCD

We evaluate ƒπmϱ, ƒ Kmρ, 1ƒρ, and mφ(ƒφmρ), extrapolated to physical quark mass, zero lattice spacing and infinite volume, for lattice QCD with Wilson quarks in the valence (quenched) approximation. The predicted ratios differ from experiment by amounts ranging from 12% to 17% equivalent to between 0.9 and 2.8 times the corresponding statistical uncertainties.
Modeling Aspects of the Dynamic Response of Heterogeneous Materials

In engineering applications, simulations involving heterogeneous materials where it is necessary to capture the local response coming from the heterogeneities is very difficult. The use of homogenization techniques can reduce the size of the problem but will miss the local effects. Homogenization can also be difficult if the constituents obey different constitutive laws. Additional complications arise if inelastic deformation occurs. In such cases a two-scale approach is preferred and this work addresses these issues in the context of a two-scale Finite Element Method (FEM). Examples of using two-scale FEM approaches are presented.
COLLECTIVE MODES IN COLOR SUPERCONDUCTING MATTER

The properties of plasmons, Nambu-Goldstone bosons and gapless Carlson-Goldman collective modes in color-flavor locked phase of color superconducting dense quark matter at finite temperature are reviewed. A possibility of a kaon condensation with an abnormal number of the NG bosons is also discussed.
Preparation and Melting Point of Octalithium Zirconate

Octalithium zirconate was prepared by heating a pelletized stoichiometric mixture of fused lithium oxide and zirconium dioxide under a dynamic vacuum to 863 K for 40 h. The melting point was determined to be 1568 ∼5 K. Chemical inertness and high lithium atom density, 5.93 ∼1022 atoms /cm3, make octalithium zirconate a candidate for a solid tritium breeder.
Comparison of high-accuracy numerical simulations of black-hole binaries with stationary-phase post-Newtonian template waveforms for initial and advanced LIGO

We study the effectiveness of stationary-phase approximated post-Newtonian waveforms currently used by ground-based gravitational-wave detectors to search for the coalescence of binary black holes by comparing them to an accurate waveform obtained from numerical simulation of an equal-mass non-spinning binary black hole inspiral, merger and ringdown. We perform this study for the initial- and advanced-LIGO detectors. We find that overlaps between the templates and signal can be improved by integrating the match filter to higher frequencies than used currently. We propose simple analytic frequency cutoffs for both initial and advanced LIGO, which achieve nearly optimal matches, and can easily be extended to unequal-mass, spinning systems. We also find that templates that include terms in the phase evolution up to 3.5 post-Newtonian (pN) order are nearly always better, and rarely significantly worse, than 2.0 pN templates currently in use. For initial LIGO we recommend a strategy using templates that include a recently introduced pseudo-4.0 pN term in the low-mass (M ≤ 35 M☉) region, and 3.5 pN templates allowing unphysical values of the symmetric reduced mass η above this. This strategy always achieves overlaps within 0.3% of the optimum, for the data used here. For advanced LIGO we recommend a strategy using 3.5 pN templates up to M = 12 M☉, 2.0 pN templates up to M = 21 M☉, pseudo-4.0 pN templates up to 65 M☉, and 3.5 pN templates with unphysical η for higher masses. This strategy always achieves overlaps within 0.7% of the optimum for advanced LIGO.
RADIATION FEEDBACK, FRAGMENTATION, AND THE ENVIRONMENTAL DEPENDENCE OF THE INITIAL MASS FUNCTION

The fragmentation of star-forming interstellar clouds, and the resulting stellar initial mass function (IMF), is strongly affected by the temperature structure of the collapsing gas. Since radiation feedback from embedded stars can modify this as collapse proceeds, feedback plays an important role in determining the IMF. However, the effects and importance of radiative heating are likely to depend strongly on the surface density of the collapsing clouds, which determines both their effectiveness at trapping radiation and the accretion luminosities of the stars forming within them. In this paper, we report a suite of adaptive mesh refinement radiation-hydrodynamic simulations using the ORION code in which we isolate the effect of column density on fragmentation by following the collapse of clouds of varying column density while holding the mass, initial density and velocity structure, and initial virial ratio fixed. We find that radiation does not significantly modify the overall star formation rate or efficiency, but that it suppresses fragmentation more and more as cloud surface densities increase from those typical of low-mass star-forming regions like Taurus, through the typical surface density of massive star-forming clouds in the Galaxy, up to conditions found only in super-star clusters. In regions of low surface density, fragmentation during collapse leads to the formation of small clusters rather than individual massive star systems, greatly reducing the fraction of the stellar population with masses 10 M ☉. Our simulations have important implications for the formation of massive stars and the universality of the IMF.
One-Point Statistics of the Cosmic Density Field in Real and Redshift Spaces with a Multiresolutional Decomposition

In this paper, we develop a method of performing the one-point statistics of a perturbed density field with a multiresolutional decomposition based on the discrete wavelet transform (DWT). We establish the algorithm of the one-point variable and its moments in considering the effects of Poisson sampling and selection function. We also establish the mapping between the DWT one-point statistics in redshift space and real space, i.e., the algorithm for recovering the DWT one-point statistics from the redshift distortion of bulk velocity, velocity dispersion, and selection function. Numerical tests on N-body simulation samples show that this algorithm works well on scales from a few hundreds to a few h-1 Mpc for four popular cold dark matter models. Taking the advantage that the DWT one-point variable is dependent on both the scale and the shape (configuration) of decomposition modes; one can design estimators of the redshift distortion parameter (β) from combinations of DWT modes. Compared with conventional β estimators, such as quadrupole-to-monopole ratio, the DWT β estimators are scale-decomposed. It is useful to consider scale-dependent effects. When the nonlinear redshift distortion is not negligible, the quadrupole-to-monopole ratio is a function of scale. This estimator would not work without adding information about the scale dependence, such as the power-spectrum index or the real-space correlation function of the random field. The DWT β estimators, however, do not need such extra information. Moreover, the scale-decomposed β estimators would also be able to reveal the scale dependence of the bias parameter of galaxies. Numerical tests show that the proposed DWT estimators are able to determine β robustly with less than 15% uncertainty in the redshift range 0 ≤ z ≤ 3.
Modelling the Quark Determinant in Full QCD Simulations

Abstract The computational requirements and dynamics of Monte Carlo simulations of unquenched QCD incorporating the infrared quark eigenmodes (up to ≈ Λ QCD ) exactly and UV modes via a loop representation are discussed. The accuracy of such a loop representation is studied for a variety of lattice volumes and quark masses. The method has been successfully applied for lattices up to 10 3 ×20 at a ≅0.17F with improved (clover) action, and allows simulations at or near kappa critical.
Detection and Symbol Synchronization for Multiple-Bit Per Photon Optical Communications

Methods of detection and synchronization in a highly efficient direct detection optical communication system are reported. Results of measurements on this moderate-rate demonstration system capable of transmitting 2.5 bits/detected photon in low background situations indicate that symbol slot synchronization is not a problem, and that a simple symbol detection scheme is adequate for this situation. This system is a candidate for interplanetary optical communications.
Analytic Quasi-Perodic Cocycles with Singularities and the Lyapunov Exponent of Extended Harper’s Model

We show how to extend (and with what limitations) Avila’s global theory of analytic SL(2,C) cocycles to families of cocycles with singularities. This allows us to develop a strategy to determine the Lyapunov exponent for the extended Harper’s model, for all values of parameters and all irrational frequencies. In particular, this includes the self-dual regime for which even heuristic results did not previously exist in physics literature. The extension of Avila’s global theory is also shown to imply continuous behavior of the LE on the space of analytic $${M_2(\mathbb{C})}$$ -cocycles. This includes rational approximation of the frequency, which so far has not been available.
Neutrino Oscillation Results from the Sudbury Neutrino Observatory

Abstract The Sudbury Neutrino Observatory (SNO) has determined the flavor content of the 8 B solar neutrino flux by measuring the rates of charged current and neutral neutrino interactions on deuterium. These results directly demonstrate neutrino flavor transformation at greater than 5σ significance. The total flux of 8 B neutrinos is found to be in good agreement with solar model predictions. Measurements of the day and night neutrino energy spectra probe models of neutrino oscillation. A global fit of SNO data and results from other solar neutrino experiments to neutrino oscillation models strongly favors the Large Mixing Angle (LMA) MSW solution.
The effects of GAAP regulation and bond market interaction on local government disclosure

Abstract This study examines the effects of disclosure regulation on municipal managers’ incentives to disclose financial report information to the bond market. I compare disclosure levels of municipal governments in Michigan, which requires GAAP, with those in Pennsylvania, which has unregulated disclosure. In the absence of disclosure regulation I find that managers have bond market-induced incentives to disclose information. Controlling for other incentives to disclose, the evidence implies that regulation induces additional disclosures for low-debt governments, and is not binding for high-debt governments.
Lessons for open standard policies: a case study of the Massachusetts experience

In 2003, Massachusetts embarked on a policy to transition to open standards for information technology. This policy led Massachusetts to switch the format of its electronic documents for its public records from a proprietary, to an open standard. This article documents this historic process, as Massachusetts was the first government to switch its information technology over to open standards. The article also analyzes the Massachusetts experience to develop a set of lessons learned. The resulting guidance should aid governments that are considering policies that encourage or favor open standards.
Space Shuttle Primary Onboard Software: STS-1 to Operational Use

The Shuttle primary onboard software and associated computer hardware comprise a data processing complex responsible for virtually all inters}stem data flow and vehicle external interfaces. Onboard functions related to guidance, navigation, flight control, systems monitoring, and management, as well as vehicle/crew/ ground interfaces, are handled by this primary system. The organization that prepared the software for the Shuttle orbital flight tests emphasized a disciplined design and development phase coupled with a thorough independent verification activity. Current focus is centered on tailoring the software organization, test philosophy, and maintenance and test facilities to the high flight frequencies and diverse missions expected during the Shuttle operational era. Shuttle Software Overview T HE successful completion of the first orbital flight of the Shuttle (STS-1) in April of 1981 marked the culmination of one of the most complex software development and integration activities ever undertaken. The evolution of the Shuttle's data processing system (DPS) has spanned more than eight years. Along with the orbital flight tests, the development program also included the approach and landing test (ALT) project during which a Shuttle vehicle was launched from a Boeing 747 aircraft and performed the terminal approach and landing portions of the Shuttle mission. Five such ALT flights were performed during August through October of 1977 providing an early test bed for both the DPS hardware and basic software architecture that would eventually be used for the orbital test missions. With respect to size and complexity, the software for the first orbital flight test of the Shuttle involved eight separately executable programs or memory configurations sharing a common operating system (see Fig. 1). These programs were stored on a mass memory tape device and were loaded into the onboard computers on crew request. One of the eight performed all functions necessary to the launch, ascent, and orbit insertion phases of the mission. Two others provided software to be used during on-orbit operations and included both navigation and control functions as well as system monitoring and management functions. Another memory configuration performed all functions necessary to the de-orbit, entry, and landing mission phases. The remaining four were designed to perform critical prelaunch and on-orbit vehicle checkout procedures. In all, these eight programs, including the software operating system, comprised approximately one-half million 32-bit words of data and executable instructions. All Shuttle applications software modules and a large part of the operating system included in these memory configurations were implemented in the HAL/S high-order language. The language and associated compiler, specifically developed for aerospace applications, are scientifically oriented and especially suited to real-time systems. The criticality of the software to the Shuttle is emphasized by its numerous interfaces with other vehicle subsystems. There are few functions integral to the Shuttle operation for
A COMPARISON OF THE AFTERGLOWS OF SHORT- AND LONG-DURATION GAMMA-RAY BURSTS

We present a comparative study of the observed properties of the optical and X-ray afterglows of short- and long-duration {gamma}-ray bursts (GRBs). Using a large sample of 37 short and 421 long GRBs, we find a strong correlation between the afterglow brightness measured after 11 hr and the observed fluence of the prompt emission. Both the optical (R band) and X-ray flux densities (F{sub R} and F{sub X} ) scale with the {gamma}-ray fluence, F {sub {gamma}}. For bursts with a known redshift, a tight correlation exists between the afterglow flux densities at 11 hr (rest frame) and the total isotropic {gamma}-ray energy, E {sub {gamma}}{sub ,ISO}: F {sub R,X} {proportional_to} E {sub {gamma}}{sub ,ISO} {sup {alpha}}, with {alpha} {approx_equal} 1. The constant of proportionality is nearly identical for long and short bursts, when E {sub {gamma}}{sub ,ISO} is obtained from the Swift data. Additionally, we find that for short busts with F {sub {gamma}} {approx}> 10{sup -7} erg cm{sup -2}, optical afterglows are nearly always detected by reasonably deep early observations. Finally, we show that the ratio F{sub R} /F{sub X} has very similar values for short and long bursts. These results are difficult to explain in the frameworkmore » of the standard scenario, since they require that either (1) the number density of the surrounding medium of short bursts is typically comparable to, or even larger than the number density of long bursts; (2) short bursts explode into a density profile, n(r) {proportional_to} r {sup -2}; or (3) the prompt {gamma}-ray fluence depends on the density of the external medium. We therefore find it likely that either basic assumptions on the properties of the circumburst environment of short GRBs or else the standard models of GRB emission must be re-examined. We believe that the most likely solution is that the ambient density surrounding typical short bursts is higher than has generally been expected: a typical value of {approx}1 cm{sup -3} is indicated. We discuss recent modifications to the standard binary merger model for short bursts which may be able to explain the implied density.« less
Private and public sector wages in Bulgaria

Abstract Private and public sector wage equations are estimated using 1995 Bulgarian data. We treat the sector of employment as endogenous and control for selectivity in the wage equations. We find that individuals have a lower probability of employment in the private sector if they have more experience, if they have higher education, and if they are ethnic Bulgarians. In addition they have a higher probability of employment in the private sector the more farmland they received in the restitution program. Wages of women in the private sector do not increase with experience or schooling. However, wages of men in the private sector increase with experience at a higher rate than in the public sector and increase with higher education at comparable rates in both sectors. Journal of Comparative Economics 32 (1) (2004) 56–72.
Ultrafine fibers formed in electric fields

Abstract We describe the preparation of several materials in the form of free-standing ultrafine fibers. The materials are made by evaporating material in an inert gas in the presence of electric fields. Fiber diameters are typically 100–300 A and irregular. Lengths of fibers or fiber bundles extend up to 10 cm. Materials range from transition metals, non-transition metals, semimetals and semiconductors. In most cases, they appear to be the smallest free-standing microwires of these lengths that have been made from these materials.
Spintronics and pseudospintronics in graphene and topological insulators.

Graphene and topological insulator two-dimensional electron systems are described by massless Dirac equations. Although the two systems have similar Hamiltonians, they are polar opposites in terms of spin–orbit coupling strength. The status of efforts to achieve long spin-relaxation times in weakly spin–orbit-coupled graphene, and large current-induced spin-polarizations in strongly spin–orbit-coupled topological insulator surface states are reviewed in this Progress Article.
PATTERNS OF GROWTH IN BIRDS

Summary Parameters used to characterize the course of growth are described, and calculated growth parameters are presented for 105 species of birds of many taxonomic groups from a wide range of geographical localities. Growth parameters are found to exhibit as much as 20% variation within a species with respect to geographic locality and time of the nesting season. There is also considerable local variation, irrespective of season and locality, which is related to nutrition and perhaps to an inherited variability. The application of curve-fitting as a method of analysing intraspecific variation is discussed briefly, and the importance of comparative growth studies is emphasized. Growth patterns are correlated with other parameters of the life-history to evaluate the extent of diversity in the course of growth. Low rates of growth and prolonged growth periods occur primarily in species large for their families and in oceanic species. In most others, high rates of growth are maintained for longer periods of time. The shape of the growth curve is not related to the mode of development (i.e. whether precocial or altricial). Overall relative, or weight-specific growth rates, as measured by the constants of fitted growth equations, are most highly correlated with the adult body size of the species, changing as the -0–278 power of adult body weight. Smaller variations in the rate of growth appear to be correlated with differences in nesting success; open-nesting passerines grow faster than hole-nesting species of a similar size. Growth rate is further correlated with brood size. Oceanic species with single egg clutches and tropical land-birds with small clutches have low growth rates. The asymptote of the growth curve of the young (in relation to the adult weight) is related to the foraging behaviour of the adults. Aerial feeders generally have high asymptotes while those of ground feeding species are usually below adult weight. These differences are related to the need in the former for well-developed flight at the time of fledging. The diversity of growth patterns is related to evolutionary trends which are the result of (1) selective forces acting at stages of the life-history cycle other than development, (2) factors which affect the survival of offspring during the growth period, and (3) adjustments made to balance the energy budget of the family group. The last trend is discussed in detail in relation to the correlations found in the analysis. Two hypotheses are presented. Firstly, in species which cannot gather enough food to support even one young at a normal growth rate, the pace of development is reduced to decrease the energetic requirements of the young. Secondly, in species with small clutches, where adjustments to feeding capacities are not readily made by changing brood size, growth rate may be adjusted to accomplish this. The lack of critical energetic data to test these hypotheses is emphasized as a major deficiency in our understanding of the breeding biology of birds.
Towards a Model for Protein Production Rates

In the process of translation, ribosomes read the genetic code on an mRNA and assemble the corresponding polypeptide chain. The ribosomes perform discrete directed motion which is well modeled by a totally asymmetric simple exclusion process (TASEP) with open boundaries. Using Monte Carlo simulations and a simple mean-field theory, we discuss the effect of one or two “bottlenecks” (i.e., slow codons) on the production rate of the final protein. Confirming and extending previous work by Chou and Lakatos, we find that the location and spacing of the slow codons can affect the production rate quite dramatically. In particular, we observe a novel “edge” effect, i.e., an interaction of a single slow codon with the system boundary. We focus in detail on ribosome density profiles and provide a simple explanation for the length scale which controls the range of these interactions.
Photonic crystal nanobeam cavity strongly coupled to the feeding waveguide

A deterministic design of an ultrahigh Q-factor, wavelength-scale photonic crystal nanobeam cavity is proposed and experimentally demonstrated. Using this approach, cavities with Q>106 and on-resonance transmission T>90% are designed. The devices, fabricated in silicon and capped with a low refractive index polymer, have experimental Q=80 000 and T=73%. This is, to the best of our knowledge, the highest transmission measured in deterministically designed, wavelength-scale high-Q cavities.
On the linearity of Artin functions

Abstract It was proved by Elkik that, under some smoothness conditions, the Artin functions of systems of polynomials over a Henselian pair are bounded above by linear functions. This paper gives a stronger form of this result for the class of excellent Henselian local rings. The linearity of Artin functions of systems of polynomials in one variable is also studied. Explicit calculations of Artin functions of monomials and determinantal ideals are also included.
Higher-Fock States and the Covariance of the Light-Front Quark Model

The light-front quark model has been successful in describing various meson properties. We apply the model to the meson weak decays and discuss the covariance of the model. We find that the inclusion of the higher-Fock state (i.e. nonvalence or so called Z-graph) contributions is necessary to recover the covariance of the light-front quark model. We present the possibility of the effective calculation of the higher-Fock state contributions to restore the covariance in the light-front model.
Chandra X-ray Sources in M101

A deep (98.2 ks) Chandra Cycle 1 observation has revealed a wealth of discrete X-ray sources as well as diffuse emission in the nearby face-on spiral galaxy M101. From this rich data set we have created a catalog of the 110 sources from the S3 chip detected with a significance of greater than 3 σ. This detection threshold corresponds to a flux of ~10-16 ergs cm-2 s-1 and a luminosity of ~1036 ergs s-1 for a distance to M101 of 7.2 Mpc. The sources display a distinct correlation with the spiral arms of M101 and include a variety of X-ray binaries, supersoft sources, supernova remnants, and other objects of which only ~27 are likely to be background sources. There are only a few sources in the interarm regions, and most of these have X-ray colors consistent with that of background active galactic nuclei. The derived log N- log S relation for the sources in M101 (background subtracted) has a slope of -0.80 ± 0.05 over the range of 1036-1038 ergs s-1. The nucleus is resolved into two nearly identical X-ray sources, each with a 0.5-2.0 keV flux of 4 × 1037 ergs s-1. One of these sources coincides with the optical nucleus, and the other coincides with a cluster of stars 110 pc to the south. The field includes 54 optically identified supernova remnants (SNRs), of which 12 are detected by Chandra. Two of the SNR sources are variable and hence must be compact objects. In total, eight of the X-ray sources show evidence for short-term temporal variation during this observation. Two of these variable sources are now brighter than the ROSAT detection threshold, but they were not detected in the previous ROSAT observations taken in 1992 and 1996. There are also two variable sources previously seen with ROSAT that apparently have faded below the Chandra detection threshold. The brightest source in the field shows extreme long-term and short-term temporal variability. At its peak brightness it has a super-Eddington luminosity greater than 1039 ergs s-1. There are 10 supersoft sources (SSSs) in the field, which can be divided into two distinct subclasses: the brighter class (three objects) has a luminosity of ~1038 ergs s-1 and a blackbody temperature of ~70 eV, whereas the other class (seven objects) is an order of magnitude fainter and has a blackbody temperature of only ~50 eV.
Self-dual and quasi self-dual algebras

Self-dual algebras are ones with an A bimodule isomorphism A → A∨op, where A∨ = Homk(A, k) and A∨op is the same underlying k-module as A∨ but with left and right operations by A interchanged. These are in particular quasi self-dual algebras, i.e., ones with an isomorphism H*(A,A) ≌ H*(A,A∨ op). For all such algebras H*(A,A) is a contravariant functor of A. Finite-dimensional associative self-dual algebras over a field are identical with symmetric Frobenius algebras; an example of deformation of one is given. (The monoidal category of commutative Frobenius algebras is known to be equivalent to that of 1+1 dimensional topological quantum field theories.) All finite poset algebras are quasi self-dual.
The gravitational sine−Gordon model

Abstract We use matrix-model results to investigate the sine-Gordon model coupled to two-dimensional gravity. For relevant (in the RG sense) potentials, we show that the c = 1 string, which appears in the ultraviolet limit of this model, flows to a set of decoupled c = 0 (pure gravity) models in the infrared. The torus partition sum, which was argued previously to count the number of string degrees of freedom and hence satisfy a new c -theorem, is shown to be a monotonically decreasing function of the scale (given by the quantum area of the world sheet). The model discussed describes an interesting time-dependent solution of two-dimensional string theory.
Signal Transit Velocities in a Turbulent Plane Jet

A turbulent jet is perturbed transverse to the flow direction by periodic pressure gradients near the nozzle exit. Transit velocities are defined in terms of the measured signal time delay for stations 8, 12, 16 nozzle widths downstream of the nozzle exit. Excitation frequencies to 800 cps are considered. Transit velocities are found to be much less than the jet centerline velocity. The results are related to the convection velocity of turbulence.
The determinants of women's international soccer performances

The expansion of economics to 'non-market topics', such as soccer, has received increased attention in recent years. However, most of the studies focus on men's performances, whereas this paper reports empirical evidence of women's international team performances. In line with the previous studies, which analysed the performance of men, the results reveal that economic, demographic, and climatic factors have a strong impact on teams' performances. The novelty of the paper is to investigate the impact of soccer tradition on women's team performances. It analyses whether there is a correlation between women's and men's team performances. In general, countries with a stronger football tradition not only have strong men's teams, but also women's teams. The findings also indicate that there is a certain competitive balance between the different football regions.
Strategic Deterrence Among Multipoint Competitors

Firms often encounter the same rivals in more than one market. Some conclude that these "multipoint" rivals should deter one another from competing, but find little empirical support. This paper pr...
A decomposition algorithm for N -player games

An N-player game can be decomposed by adding a coordinator who interacts bilaterally with each player. The coordinator proposes profiles of strategies to the players, and his payoff is maximized when players’ optimal replies agree with his proposal. When the feasible set of proposals is finite, a solution of an associated linear complementarity problem yields an equilibrium of the approximate game and thus an approximate equilibrium of the original game. Computational efficiency is improved by using vertices of a triangulation of the players’ strategy space for the coordinator’s pure strategies. Computational experience is reported.
Why Impacted Yarns Break at Lower Speed Than Classical Theory Predicts

Fabrics are an extremely important element of body armors and other armors. Understanding fabrics requires understanding how yarns deform. Classical theory has shown very good agreement with the deformation of a single yarn when impacted. However, the speed at which a yarn would break based on this classical theory is not correct; it has been experimentally noted that yarns break when impacted at a lower velocity. This paper explores the mechanism of yarn breakage. The problem of the strike of a yarn by a flat-faced projectile is analytically solved for early times. It is rigorously demonstrated that when a flat-faced projectile strikes a yarn, the breaking speed will always be at least 11% less than the classical-theory result. It is further shown that when the yarn material in front of the projectile is “bounced” off the front surface due to the impact, that the breaking speed is further reduced. If the yarn bounces elastically off the surface due to the impact at twice the impact velocity (the theoretical maximum), there is a 40% reduction in the breaking speed of a yarn. A beautiful theory of yarn deformation under an applied boundary condition was developed by Smith [1,2]. This theory was developed in the context of impact on yarns. There has been extensive experimental work showing that the wave propagation speeds of the longitudinal and transverse waves and the subsequent deflections are well modeled by the theory. However, numerous researchers have realized that the yarn breaking speed inferred from the classical theory is larger than what is observed in experiment. Why are the impacted yarns breaking at lower speeds than the theory predicts? Most often yarns are impacted by fragment simulating projectiles or right circular cylinders. These projectiles have flat impact faces. In our computational investigation of this phenomenon, we have noticed that the flat face impact leads to a “bounce” of the yarn off the impact surface (Fig. 1). A longitudinal and transverse wave are produced in the yarn, originating at the impactor edges, traveling both outward away from the impactor and inward where the waves from opposing impactor edges. The waves meet at the geometric center of the yarn in front of the projectile; the stress and strain in the yarn double, leading to higher stresses. After this first wave effect, we also see, during more complicated wave interactions a small increase in stress until the material is relieved to the classical (Smith) solution stress at later time.
Factoring integers with Young's N-slit interferometer.

We show that a Young's N-slit interferometer can be used to factor the integer N. The device could factor four- or five-digit numbers in a practical fashion. This work shows how number theory may arise in physical problems, and may provide some insight as to how quantum computers can carry out factoring problems by interferometric means. \textcopyright{} 1996 The American Physical Society.