cssi/SciSciGPT-SciSciNet huggingface dataset:
Strobes: shared-time repair of big electronic systems

The trend towards larger, more elaborate, and more complex computer systems is gradually modifying many programming and engineering techniques. The sheer bulk of equipment required by contemporary computer centers, in itself, creates new and severe problems in many areas. In particular, the maintenance of big systems has been complicated by three important characteristics: redundancy, complexity, and expense.
RR LYRAE VARIABLES IN THE LOCAL GROUP DWARF GALAXY NGC 147

We investigate the RR Lyrae (RRL) population in NGC 147, a dwarf satellite galaxy of M31 (Andromeda). We used both Thuan-Gunn g-band ground-based photometry from the literature and Hubble Space Telescope Wide Field Planetary Camera 2 archival data in the F555W and F814W passbands to investigate the pulsation properties of RRL variable candidates in NGC 147. These data sets represent the two extreme cases often found in RRL studies with respect to the phase coverage of the observations and the quality of the photometric measurements. Extensive artificial variable star tests for both cases were performed. We conclude that neither data set is sufficient to confidently determine the pulsation properties of the NGC 147 RRLs. Thus, while we can assert that NGC 147 contains RRL variables, and therefore a population older than approx10 Gyr, it is not possible at this time to use the pulsation properties of these RRLs to study other aspects of this old population. Our results provide a good reference for gauging the completeness of RRL variable detection in future studies.
A no-go theorem for one-layer feedforward networks

It is often hypothesized that a crucial role for recurrent connections in the brain is to constrain the set of possible response patterns, thereby shaping the neural code. This implies the existence of neural codes that cannot arise solely from feedforward processing. We set out to find such codes in the context of one-layer feedforward networks and identified a large class of combinatorial codes that indeed cannot be shaped by the feedforward architecture alone. However, these codes are difficult to distinguish from codes that share the same sets of maximal activity patterns in the presence of subtractive noise. When we coarsened the notion of combinatorial neural code to keep track of only maximal patterns, we found the surprising result that all such codes can in fact be realized by one-layer feedforward networks. This suggests that recurrent or many-layer feedforward architectures are not necessary for shaping the (coarse) combinatorial features of neural codes. In particular, it is not possible to infer a computational role for recurrent connections from the combinatorics of neural response patterns alone. Our proofs use mathematical tools from classical combinatorial topology, such as the nerve lemma and the existence of an inverse nerve. An unexpected corollary of our main result is that any prescribed (finite) homotopy type can be realized by a subset of the form , where is a polyhedron.
Dynamic Loss Minimization Using Improved Deadbeat-Direct Torque and Flux Control for Interior Permanent-Magnet Synchronous Machines

Direct torque control (DTC) has become a widely acceptable alternative to field-oriented control. Deadbeat-direct torque and flux control (DB-DTFC) is a significant improvement over the classical DTC methods and provides opportunities for fast torque control and dynamic loss minimization control. The existing high-switching DB-DTFC solution is based on approximate discrete-time models. This paper presents a more accurate model so that, even at low switching frequencies, proper DB-DTFC control can be achieved. The instantaneous dynamic loss model, which is a function of volt-second selection in each switching period, containing nonlinear effects such as minor hysteresis loops is theoretically derived and evaluated by both FEA simulation and experiments. With this calibrated dynamic loss model, deadbeat dynamic loss minimization control is implemented and integrated in DB-DTFC. Finally, the dynamic loss minimization control is evaluated experimentally and compared with the existing steady-state loss minimization control.
A relative rate study of the reaction of Cl atoms with a series of alkyl nitrates and nitro alkanes in air at 295±2 K

The relative rate technique has been used to measure rate constants for the reaction of chlorine atoms with nitro methane, nitro ethane, nitro propane, nitro butane, nitro pentane, ethyl nitrate, isopropyl nitrate, n-propyl nitrate, 2-pentyl nitrate, and 2-heptyl nitrate. Decay rates of these organic species were measured relative to one or more of the following reference compounds; n-butane, ethane, chloroethane, and methane. Using rate constants of 2.25 × 10−10 5.7 × 10−11, 8.04 × 10−12, and 1.0 × 10−13 cm3 molecule−1 s−1 for the reaction of Cl atoms with n-butane, ethane, chloroethane, and methane, respectively, the following rate constants were derived, in units of cm3 molecule−1 s−1: nitro methane, <7 × 10−15; nitro ethane, (2.05 ± 0.14) × 10−13; nitro propane, (1.13 ± 0.05) × 10−11; nitro butane, (5.13 ± 0.68) × 10−11; nitro pentane, (1.40 ± 0.14) × 10−10; ethyl nitrate, (3.70 ± 0.24) × 10−12; n-propyl nitrate, (2.15 ± 0.13) × 10−11; i-propyl nitrate, (3.94 ± 0.48) × 10−12; 2-pentyl nitrate, (1.00 ± 0.06) × 10−10; and 2-heptyl nitrate, (2.84 ± 0.50) × 10−10. Quoted errors represent 2σ and do not include possible systematic errors due to errors in the reference rate constants. Experiments were performed at 295 ± 2 K and atmospheric pressure (≃740 torr) of synthetic air. The results are discussed with respect to the previous literature data and to the modeling of these compounds in the atmosphere.
Necessary and sufficient conditions for collision-free hashing

This paper determines an exact relationship between collision-free hash functions and other cryptographic primitives. Namely, it introduces a new concept, the pseudopermutation, and shows that the existence of collision-free hash functions is equivalent to the existence of claw-free pairs of pseudopermutations. We also give a simple construction of collision-free hash functions from everywhere-defined claw-free (pseudo-) permutations.
Regional atmospheric circulation change in the North Pacific during the Holocene inferred from lacustrine carbonate oxygen isotopes, Yukon Territory, Canada

Analyses of sediment cores from Jellybean Lake, a small, evaporation-insensitive groundwater-fed lake, provide a record of changes in North Pacific atmospheric circulation for the last ∼7500 yr at 5- to 30-yr resolution. Isotope hydrology data from the southern Yukon indicate that the oxygen isotope composition of water from Jellybean Lake reflects the composition of mean-annual precipitation, δ18Op. Recent changes in the δ18O of Jellybean sedimentary calcite (δ18Oca) correspond to changes in the North Pacific Index (NPI), a measure of the intensity and position of the Aleutian Low (AL) pressure system. This suggests that δ18Op variability was related to the degree of fractionation during moisture transport from the Gulf of Alaska across the St. Elias Mountains and that Holocene shifts were controlled by the intensity and position of the AL. Following this model, between ∼7500 and 4500 cal yr B.P., long-term trends suggest a predominantly weaker and/or westward AL. Between ∼4500 and 3000 cal yr B.P. the AL shifted eastward or intensified before shifting westward or weakening between ∼3000 and 2000 cal yr B.P. Rapid shifts eastward and/or intensification occurred ∼1200 and 300 cal yr B.P. Holocene changes in North Pacific atmospheric circulation inferred from Jellybean Lake oxygen isotopes correspond with late Holocene glacial advances in the St. Elias Mountains, changes in North Pacific salmon abundance, and shifts in atmospheric circulation over the Beaufort Sea.
The effect of menarcheal age on anthropometric, limb length, and bone measures in Hutterite and non-Hutterite women

The age women reach menarche may affect bone length and mass. Some studies show an earlier menarcheal age (MA) results in a shorter stature and increased body fat. We hypothesized that Hutterite women have a shorter height and limb length, but greater bone mass and areal bone mineral density (aBMD) than non-Hutterites. Results are from a secondary analysis of 344 (198 Hutterite) healthy, pre-menopausal women aged 20240 years who participated in the South Dakota Rural Bone Health Study. Bone measures were obtained by DXA (spine, hip and total body) and pQCT (4 and 20% distal radius). MA correlated with year of birth (r 52 0.10, P 5 0.08) indicating a trend to- ward a younger MA for women born in more recent years. MA was inversely associated with current weight (r 5 20.11, P < 0.05), percent body fat (r 52 0.16, P < 0.01), femoral neck BMC (r 52 0.18, P 5 0.003), femoral neck aBMD (r 52 0.21, P < 0.001), hip aBMD (r 52 0.22, P < 0.001) and trabecular volumetric BMD (vBMD) (r 52 0.14, P 5 0.03). Hutterite women had a younger MA than non-Hutterite women (12.3 6 1.3 vs. 13.0 6 1.3 yr, P < 0.001). In final regression models controlling for diet and activity patterns, Hutterite compared to non-Hutterite women had shorter standing height (162 6 0.4 vs. 166 6 0.4 cm, P < 0.001), forearm length (258 6 0.8 vs. 261 6 0.9 mm, P 5 0.04); and leg length (76 6 0.2 vs. 77 6 0.3 cm, P < 0.01) as hypothesized, but MA did not predict these outcomes. In conclusion, younger MA in Hutterite women did not explain their shorter standing height and limb lengths, but total hip aBMD was inversely associated with MA and greater in Hutterite than non-Hutterite women. Am. J. Hum. Biol. 20:693-699, 2008. ' 2008 Wiley-Liss, Inc.
Focused iterative testing: a test automation case study

Timing-related defects are among the most difficult types of defects to catch while testing software. They are by definition difficult to reproduce and hence difficult to debug. Not all components of a software system have timing-related defects. For example, either a parser can analyze an input or it cannot. However, systems that have concurrent threads such as database systems are prone to timing-related defects. As a result, software developers must tailor testing to exploit vulnerabilities that occur because of threading. This paper presents the Focused Iterative Testing (FIT) approach, which uses a repetitive and iterative approach to find timing-related defects and target product areas with multithreaded characteristics by executing system tests with a multi-user test suite.
Uncovering Planetary Nebulae in Early-Type Galaxies using the Rutgers Fabry-Pérot

We report on observations of four early-type galaxies performed with the Rutgers Fabry-P?rot in order to search for planetary nebulae (PNe) in these systems. The aim is to use the PNe as kinematic tracers of the galaxy potential. We describe our data reduction and analysis procedure and show that the proper calibration of our detection statistic is crucial in getting down to our limiting magnitude of m5007 = 26.1. In the case of the two Leo galaxies, we find moderately sized samples: 54 PNe in NGC 3379 and 50 PNe in NGC 3384; NGC 4636 (two PNe) and NGC 1549 (six PNe) are included for completeness. We present our samples in tabular form, as well as the spectrum for each PN. We constructed simple nonparametric spherical mass models for NGC 3379 using a Monte Carlo Markov chain method to explore the space of likely mass models. We find a remarkably constant mass-to-light ratio within five half-light radii with an overall B-band mass-to-light ratio of ~5. A simple mass-to-light ratio estimate for NGC 3384 yields B ~ 11, but it is likely an overestimate.
CONVECTION DURING THE LATE STAGES OF SIMMERING IN TYPE Ia SUPERNOVAE

Following the unstable ignition of carbon, but prior to explosion, a white dwarf (WD) in a Type Ia supernova (SN Ia) undergoes a simmering phase. During this time, a central convective region grows and encompasses ~1 M☉ of the WD over a timescale of ~103 yr, which sets the thermal and turbulent profile for the subsequent explosion. We study this time-dependent convection and summarize some of the key features that differ from the traditional, steady-state case. We show that the long conductive timescale above the convective zone and the extraction of energy to heat the WD core lead to a decrease of the convective luminosity and the characteristic velocities near the convective zone's top boundary. In addition, differences in the composition between the convective core and the conductive exterior will significantly alter the location of this boundary. In this respect, we find the biggest effect to be due to complete 22Ne sedimentation prior to carbon ignition. These effects add diversity to the possible WD models, which may alter the properties of SN Ia explosions.
Time-analysis of logical processes in man

Pattern recognition in man is assumed to be mediated by a hierarchical organization of specialized systems, each of which abstracts a certain property from its input. Some characteristics of the overall organization can be inferred from the times that are needed to carry out various information processes. These times can be determined independently of reaction factors by a scanning method. Preliminary results with the method demonstrate the flexibility of the processing hierarchy in man. They also suggest that parallel processing is used under some conditions, while sequential procedures are dominant in others.
Lateral mode discrimination in surface emitting DBR lasers with cylindrical symmetry

The effective reflectivity and the threshold gain of all lateral modes in a surface emitting DBR laser with cylindrical symmetry are analyzed using the coupled-mode approach. Our results indicate that when a cavity is designed for operation in the odd modes, all even modes are effectively eliminated. A small perturbation is introduced into the complex dielectric constant of the active region to suppress the unwanted lateral modes of odd symmetry. The model predicts that lasing will occur in a single mode with a narrow far-field pattern. >
MULTIBUS® continues to evolve to meet the challenges of the VLSI revolution

MULTIBUS is the world's most popular microprocessor system architecture. The success of the MULTIBUS is attributable to its compatible evolution, always meeting the demands of new VLSI microprocessors without forsaking compatibility with existing products. New system architecture's need for the use of large amounts of high performance memory is the motivation for continued MULTIBUS evolution. This need is addressed through the introduction of the Local Bus Extention (iLBX™). Whereas the local bus under the previous definition was physically limited to on-board execution, the iLBX evolution allows the local bus to span up to five separate boards. The benefit of the LBX is the ability to achieve on-board performance when operating out of physically separate boards. Intel's iSBC(R) 286/10 single board computer combines the latest VLSI with the iLBX extension, creating a new level of microcomputer system performance. This new board vividly demonstrates that the MULTIBUS continues to evolve to meet the challenges of the VLSI revolution.
The British State and the Irish Rebellion of 1916: An Intelligence Failure Or a Failure of Response?

The teleological narrative that has dominated the handling of intelligence by the British state in the events that led up to the 1916 Irish Rebellion in Dublin has been characterised as a cocktail of incompetence and mendacity. Using new and existing archive material this article argues that both the cabinet in London and key members of the Irish Executive in Dublin were supplied with accurate and timely intelligence by the Admiralty's signals intelligence unit, the Royal Irish Constabulary and the Dublin Metropolitan Police with respect to this event. Far from being a failure of intelligence here is evidence to show that there occurred a failure of response on behalf of key decision-makers. The warnings that were given by intelligence organisations were filtered through the existing policy preferences and assumptions. As a result of these factors accurate evaluations and sound judgement were not exercised by key officials, such as Sir Matthew Nathan, in Dublin Castle.
Exterminator: Automatically correcting memory errors with high probability

Programs written in C and C++ are susceptible to memory errors, including buffer overflows and dangling pointers. These errors, which can lead to crashes, erroneous execution, and security vulnerabilities, are notoriously costly to repair. Tracking down their location in the source code is difficult, even when the full memory state of the program is available. Once the errors are finally found, fixing them remains challenging: even for critical security-sensitive bugs, the average time between initial reports and the issuance of a patch is nearly 1 month. We present Exterminator, a system that automatically corrects heap-based memory errors without programmer intervention. Exterminator exploits randomization to pinpoint errors with high precision. From this information, Exterminator derives runtime patches that fix these errors both in current and subsequent executions. In addition, Exterminator enables collaborative bug correction by merging patches generated by multiple users. We present analytical and empirical results that demonstrate Exterminator's effectiveness at detecting and correcting both injected and real faults.
Direct numerical simulations of type Ia supernovae flames II: The Rayleigh-Taylor instability

A Type Ia supernova explosion likely begins as a nuclear runaway near the center of a carbon-oxygen white dwarf. The outward propagating flame is unstable to the Landau-Darrieus, Rayleigh-Taylor, and Kelvin-Helmholtz instabilities, which serve to accelerate it to a large fraction of the speed of sound. We investigate the Rayleigh-Taylor unstable flame at the transition from the flamelet regime to the distributed-burning regime, around densities of 10e7 gm/cc, through detailed, fully resolved simulations. A low Mach number, adaptive mesh hydrodynamics code is used to achieve the necessary resolution and long time scales. As the density is varied, we see a fundamental change in the character of the burning--at the low end of the density range the Rayleigh-Taylor instability dominates the burning, whereas at the high end the burning suppresses the instability. In all cases, significant acceleration of the flame is observed, limited only by the size of the domain we are able to study. We discuss the implications of these results on the potential for a deflagration to detonation transition.
Noninvasive Doppler blood pressure monitoring in the monoplace hyperbaric chamber.

We describe a noninvasive method of monitoring blood pressure in the monoplace hyperbaric chamber. A standard blood pressure cuff was placed on the patient's arm. A Doppler probe, linked to an ultrasonic Doppler flow detector outside the chamber, was secured over the patient's radial artery. Cuff inflation tubing and the Doppler probe wires were passed into the chamber by modifying a standard disposable hyperbaric intravenous pass-through. Blood pressure readings were determined by inflating and slowly deflating the cuff from outside the chamber while observing the sphygmomanometer within the chamber and listening for the first audible flow signal from the Doppler detector, corresponding to the systolic blood pressure. To minimize the risk of fire in the oxygen-filled monoplace hyperbaric chamber, the patient, Doppler detector, and chamber were grounded. Doppler readings obtained from nine normal subjects whose arterial pressures were being measured with indwelling radial arterial catheters (approved as part of another study by the hospital's Investigational Review Board) compare closely with the subject's blood pressures measured with this noninvasive method: 114±7.6 mm Hg (mean±1 SD) compared to 112±8.1 mm Hg, respectively (n=92 measurements in 8 subjects). We conclude that this noninvasive method of monitoring blood pressure within the monoplace hyperbaric chamber is accurate and suitable for monoplace clinical purposes.
Computing the Fundamental Matrix for a Reducible Markov Chain

We present a new partitioning algorithm for computing the fundamental matrix for a nonirreducible Markov chain. The algorithm, called matrix reduction, has three steps: (1) augmentation; (2) stochastic complementation; and (3) a backward pass. We show that matrix reduction is equivalent to performing matrix inversion with Gaussian elimination to compute the fundamental matrix. We execute matrix reduction without subtractions to enhance numerical stability. We apply matrix reduction to a small example problem modeling patient flow in a hospital.
The Influence of Massive Planet Scattering on Nascent Terrestrial Planets

In most extrasolar planetary systems, the present orbits of known giant planets admit the existence of stable terrestrial planets. Those same giant planets, however, have typically eccentric orbits that hint at violent early dynamics less benign for low-mass planet formation. Under the assumption that massive planet eccentricities are the endpoint of gravitational scattering in multiple planet systems, we study the evolution of the building blocks of terrestrial planets during the scattering process. We find that, typically, evolutionary sequences that result in a moderately eccentric giant planet orbiting at a 2.5 AU eject over 95% of the material initially present within the habitable zone. Crossing orbits largely trigger the ejection and leave the surviving material with a wide dispersion in semimajor axis, eccentricity, and inclination. Based on these results, we predict that radial velocity follow-up of terrestrial planet systems found by Kepler will find that these are anticorrelated with the presence of eccentric giant planets orbiting at a few AU.
Thouless energy and correlations of QCD Dirac eigenvalues

Eigenvalues and eigenfunctions of the QCD Dirac operator are studied for gauge field configurations given by a liquid of instantons. We find that for energy differences δE below an energy scale Ec the eigenvalue correlations are given by random matrix theories with the chiral symmetries of the QCD partition function. For eigenvalues near zero this energy scale shows a weak volume dependence that is not consistent with Ec ∼ 1L2 which might be expected from the pion Compton wavelength and from the behavior of the Thouless energy in mesoscopic systems. However, the numerical value of Ec for our largest volumes is in rough agreement with estimates from the pion Compton wavelength. A scaling behavior consistent with Ec ∼ 1/L2 is found in the bulk of the spectrum. For δE > Ec the number variance shows a linear dependence with a slope which is larger than the non-zero multifractality index of the wave functions. Finally, the average spectral density and the scalar susceptibilities are discussed in the context of quenched chiral perturbation theory. We argue that a non-zero value of the disconnected scalar susceptibility requires a linear dependence of the number variance on δE. © 1998 Elsevier Science B.V.
Spatial modeling of agricultural land use change at global scale

Abstract Long-term modeling of agricultural land use is central in global scale assessments of climate change, food security, biodiversity, and climate adaptation and mitigation policies. We present a global-scale dynamic land use allocation model and show that it can reproduce the broad spatial features of the past 100 years of evolution of cropland and pastureland patterns. The modeling approach integrates economic theory, observed land use history, and data on both socioeconomic and biophysical determinants of land use change, and estimates relationships using long-term historical data, thereby making it suitable for long-term projections. The underlying economic motivation is maximization of expected profits by hypothesized landowners within each grid cell. The model predicts fractional land use for cropland and pastureland within each grid cell based on socioeconomic and biophysical driving factors that change with time. The model explicitly incorporates the following key features: (1) land use competition, (2) spatial heterogeneity in the nature of driving factors across geographic regions, (3) spatial heterogeneity in the relative importance of driving factors and previous land use patterns in determining land use allocation, and (4) spatial and temporal autocorrelation in land use patterns. We show that land use allocation approaches based solely on previous land use history (but disregarding the impact of driving factors), or those accounting for both land use history and driving factors by mechanistically fitting models for the spatial processes of land use change do not reproduce well long-term historical land use patterns. With an example application to the terrestrial carbon cycle, we show that such inaccuracies in land use allocation can translate into significant implications for global environmental assessments. The modeling approach and its evaluation provide an example that can be useful to the land use, Integrated Assessment, and the Earth system modeling communities.
The Developing World is Poorer than We Thought, But No Less Successful in the Fight Against Poverty

A new data set on national poverty lines is combined with new price data and almost 700 household surveys to estimate absolute poverty measures for the developing world. We find that 25% of the population lived in poverty in 2005, as judged by what “poverty” typically means in the world's poorest countries. This is higher than past estimates. Substantial overall progress is still indicated—the corresponding poverty rate was 52% in 1981—but progress was very uneven across regions. The trends over time and regional profile are robust to various changes in methodology, though precise counts are more sensitive.
AN EFFICIENT AMIDE-FORMING REACTION USING TRIBUTYLTRICHLOROMETHYLPHOSPHONIUM CHLORIDE

An efficient and expeditious amide-forming reaction is described via a combination of tributylphosphine and carbon tetrachloride (in situ generation of tributyltrichloromethylphosphonium chloride) in the absence of tertiary amines.
Band-Limited Localized Parseval Frames and Besov Spaces on Compact Homogeneous Manifolds

In the last decade, methods based on various kinds of spherical wavelet bases have found applications in virtually all areas where analysis of spherical data is required, including cosmology, weather prediction, and geodesy. In particular, the so-called needlets (= band-limited Parseval frames) have become an important tool for the analysis of Cosmic Microwave Background (CMB) temperature data. The goal of the present paper is to construct band-limited and highly localized Parseval frames on general compact homogeneous manifolds. Our construction can be considered as an analogue of the well-known φ-transform on Euclidean spaces.
Teaching Post Keynesian exchange rate theory

The goal of this paper is to provide a model and method for those wishing to include the Post Keynesian perspective when teaching exchange rate theory. It begins by reviewing neoclassical approaches (purchasing power parity, the monetary model, and the Dornbusch model) and then develops a graphical Post Keynesian model that is based on Keynes's Z-D diagram, endogenous money, a currency market driven by portfolio capital flows, and no assumption of a tendency toward full employment or balanced trade. The model is then used to look at historical examples and policy.
Method of Measuring Deep Sea Tides

IN the course of a conversation with William Beebe regarding plans for work to be done on his oceanic expedition, my attention was directed to the fact that no method had been devised up to the present time for recording the rise and fall of the tides except in comparatively shallow waters. It appeared that the Hydrographic Office was very anxious to have data regarding the tides at localities where the depth of the ocean was measured in miles.
CYCLOTRON MODELING PHASE-RESOLVED INFRARED SPECTROSCOPY OF POLARS. III. AM HERCULIS AND ST LEO MINORIS

We present phase-resolved low-resolution infrared spectra of AM Her and ST LMi, two low-field polars that we observed with SPEX on the IRTF. Optical/NIR light curves are also published to help constrain the viewing geometry and brightness of the objects at the time they were observed. Currently, only limited IR spectra have been published for these objects, and none with the phase-coverage presented here. In both cases, the resulting spectra are dominated by emission from the secondary star in the NIR. However, the emission regions are also self-eclipsed, allowing us to isolate the cyclotron emission through subtraction of the dim-phase spectrum. We use a constant-lambda prescription to model the changing cyclotron features seen in the resulting data. For AM Her, we find a best-fit model of B = 13.6 MG, kT = 4.0 keV, and log Λ = 5.0. The cyclotron derived accretion geometry is consistent with i = 50° and β = 85°. For ST LMi, B = 12.1 MG, kT = 3.3 keV, and log Λ = 5.7, with i = 55° and β = 128°.
NUCLEON STRUCTURE AND PARITY-VIOLATING ELECTRON SCATTERING

We review the area of strange quark contributions to nucleon structure. In particular, we focus on current models of strange quark vector currents in the nucleon and the associated parity-violating elastic electron scattering experiments from which vector and axial-vector currents are extracted.
Nonbinary quantum Reed-Muller codes

We construct nonbinary quantum codes from classical generalized Reed-Muller codes and derive the conditions under which these quantum codes can be punctured. We provide a partial answer to a question raised by Grassl, Beth and Rotteler on the existence of q-ary quantum MDS codes of length n with q les n les q2 - 1
The Effect of Spatially Correlated Roughness and Boundary Conditions on the Conduction of Heat Through a Slab

The nominally one-dimensional conduction of heat through a slab becomes two dimensional when one of the surfaces is rough or when the boundary conditions are spatially nonuniform. This paper develops the stochastic equations for a slab whose surface roughness or convective boundary condition is spatially correlated with correlation lengths ranging from 0 (white noise) to a length long in comparison to the slab thickness. The effect is described in terms of the standard deviation and the resulting spatial correlation of the heat flux as a function of depth into the slab. In contrast to the expectation that the effect is monotonic with respect to the correlation length, it is shown that the effect is maximized at an intermediate correlation length. It is also shown that roughness or a random convective heat transfer coefficient have essentially the same effects on the conducted heat, but that the combination results in a much deeper penetration than does each effect individually. In contrast to the usual methods of solving stochastic problems, both the case of a rough edge and a smooth edge with stochastic convective heat transfer coefficients can only be treated with reasonable computational expense by using direct Monte Carlo simulations.
Rural poverty dynamics: development policy implications

This article explores the useful distinction between chronic and transitory poverty in understanding rural welfare dynamics, highlighting the possibility of poverty traps and their implications for “cargo net” policies to build up productive assets and “safety net” policies to protect such assets. We discuss the methodological difficulties in identifying and explaining either poverty traps or the critical thresholds that are their defining feature. A few empirical examples from sub-Saharan Africa illustrate the likely existence of poverty traps that help to explain chronic rural poverty.
On Krammer's representation of the braid group

A connection is made between the Krammer representation and the Birman-Murakami-Wenzl algebra. Inspired by a dimension argument, a basis is found for a certain irrep of the algebra, and relations which generate the matrices are found. Following a rescaling and change of parameters, the matrices are found to be identical to those of the Krammer representation. The two representations are thus the same, proving the irreducibility of one and the faithfulness of the other.
Chandra High-Resolution X-Ray Spectroscopy of the Fe K Line in the Seyfert 1 Galaxy NGC 3783

We report on the results of detailed X-ray spectroscopy of the Fe K region in the Seyfert 1 galaxy NGC 3783 using the Chandra High Energy Grating Transmission Spectrometer (HETGS). There were five observations over an interval of ~125 days in 2001, each with an exposure time of ~170 ks. The combined data constitute the highest signal-to-noise Fe K spectrum having the best velocity resolution in the Fe K band to date (FWHM ~ 1860 km s-1). The combined data show a resolved Fe Kα line core (FWHM = 1700 km s-1) with a center energy of 6.397 ± 0.003 keV, consistent with an origin in neutral or lowly ionized Fe, located between the BLR and NLR, as found by Kaspi et al. in 2002. We also find that excess flux around the base of the Fe Kα line core can be modeled with either a Compton-scattering "shoulder" or an emission line (with about the same flux as the line core) from a relativistic accretion disk, having an inclination angle of 11° or less. This disk-line model is as good as a Compton-shoulder model for the base of the Fe Kα line core. In the latter model, we measured the column density to be 7.5 × 1023 cm-2, which corresponds to a Thomson optical depth of ~0.60, so the line-emitting matter is not quite Compton-thick. An intrinsic width of 1500 km s-1 FWHM is still required in this model. Moreover, more complicated scenarios involving both a Compton shoulder and a disk line cannot be ruled out. We confirm an absorption feature due to He-like Fe (FWHM = 6405 km s-1) found in previous studies.
Comparative Pharmacokinetics of Coumarin Anticoagulants XLIV: Dose-dependent Pharmacokinetics of Warfarin in Rats

The purpose of this investigation was to determine the effect of dose on warfarin pharmacokinetics in rats. First, in a crossover experiment, rats received 14C-warfarin, 0.2 mg/kg iv, 12 hr after an injection of either nonradioactive warfarin (0.5 mg/kg) or saline solution. Warfarin concentrations in plasma declined triexponentially as a function of time. Pharmacokinetic analysis revealed that pretreatment with warfarin significantly decreased the apparent volume of distribution, total plasma clearance, and intrinsic plasma clearance of the drug. In the second part of the investigation, rats received single intravenous warfarin injections in the order of 0.1-1.0-0.1 or 1.0-0.1-1.0 mg/kg at 2-week intervals. The apparent volume of distribution, total plasma clearance, and intrinsic plasma clearance of the 1.0-mg/kg warfarin dose were appreciably lower than those of the 0.1-mg/kg dose. The decrease in the apparent volume of distribution of warfarin with increasing dose is consistent with the previously observed concentration dependence in hepatic uptake of the drug.
I-brane dynamics

We study the dynamics near a 1+1 dimensional intersection of two orthogonal stacks of fivebranes in type IIB string theory, using an open string description valid at weak coupling, and a closed string description valid at strong coupling. The weak coupling description suggests that this system is invariant under eight supercharges with a particular chirality in 1+1 dimensions, and its spectrum contains chiral fermions localized at the intersection. The closed string description leads to a rather different picture — a three dimensional Poincare invariant theory with a gap and sixteen supercharges. We show that this dramatic change in the behavior of the system is partly due to anomaly inflow. Taking it into account leads to a coherent picture, both when the fivebranes in each stack are coincident and when they are separated.
The monitoring role of insiders

Abstract Conventional wisdom suggests that giving monitored agents an oversight role may blunt the effectiveness of the monitoring process. In contrast, I show that less independent boards can sometimes be more effective at monitoring. Fully independent boards have incentives to shirk monitoring ex post, after the agents’ productive inputs are sunk, if the boards cannot commit ex ante to monitoring. However, boards with inside directors may have incentives to monitor the agents ex post. The demand for insiders thus arises endogenously as they allow boards to indirectly commit to monitoring and thereby facilitate the monitoring process.
Ground State Structure of a Coupled 2-Fermion System in Supersymmetric Quantum Mechanics

Abstract We prove the uniqueness of the ground state for a supersymmetric quantum mechanical system of two fermions and two bosons, which is closely related to theN=1 WZ-model. The proof is constructive and gives detailed information on what the ground state looks like
Inelastic electron scattering by collective charge density excitations at the surface of a semiconductor superlattice

Abstract Using linear response theory and the diagonal approximation we calculate exactly and analytically surface response of a semi-infinite semiconductor superlattice to an electron moving in the vacuum. This response determines the scattering process. The electron energy loss spectrum due to surface intra- and intersubband plasmons is predicted for the first time.
Scattering in tight atom waveguides

Using the Theory of Scattering in Restricted Geometries developed by A. Lupu-Sax as a starting point, we present a comprehensive multi-channel theory of atom-atom scattering in tight atom waveguides.
A Farey Fraction Spin Chain

We introduce a new number-theoretic spin chain and explore its thermodynamics and connections with number theory. The energy of each spin configuration is defined in a translation-invariant manner in terms of the Farey fractions, and is also expressed using Pauli matrices. We prove that the free energy exists and a phase transition occurs for positive inverse temperature β= 2. The free energy is the same as that of related, non-translation-invariant number-theoretic spin chain. Using a number-theoretic argument, the low-temperature (β > 3) state is shown to be completely magnetized for long chains. The number of states of energy E= log(n) summed over chain length is expressed in terms of a restricted divisor problem. We conjecture that its asymptotic form is (n log n), consistent with the phase transition at β= 2, and suggesting a possible connection with the Riemann ζ-function. The spin interaction coefficients include all even many-body terms and are translation invariant. Computer results indicate that all the interaction coefficients, except the constant term, are ferromagnetic.
high-performance equation solvers and their impact on finite element analysis

The role of equation solvers in modern structural analysis software is described. Direct and iterative equation solvers which exploit vectorization on modern high-performance computer systems are described and compared. The direct solvers are two Cholesky factorization methods. The first method utilizes a novel variable-band data storage format to achieve very high computation rates and the second method uses a sparse data storage format designed to reduce the number od operations. The iterative solvers are preconditioned conjugate gradient methods. Two different preconditioners are included; the first uses a diagonal matrix storage scheme to achieve high computation rates and the second requires a sparse data storage scheme and converges to the solution in fewer iterations that the first. The impact of using all of the equation solvers in a common structural analysis software system is demonstrated by solving several representative structural analysis problems.
Synthesis of 2',3'-dideoxy-3'-fluoro-L-ribonucleosides as potential antiviral agents from D-sorbitol.

Abstract 2′,3′-Dideoxy-3′-fluoro- l -ribonucleosides were synthesized as potential antiviral agents. The key intermediate, methyl 5-O-benzoyl-2,3-dideoxy-3-fluoro- l -ribofuranoside, which was prepared from d -sorbitol, was condensed with pyrimidine and purine bases to obtain the respective nucleosides. Among them, the cytosine analogue 2′,3′-dideoxy-3′-fluoro-α- l -cytidine showed a moderate anti-HBV activity.
Edge Nonlinear Optics on a MoS2 Atomic Monolayer

The translational symmetry breaking of a crystal at its surface may form two-dimensional (2D) electronic states. We observed one-dimensional nonlinear optical edge states of a single atomic membrane of molybdenum disulfide (MoS2), a transition metal dichalcogenide. The electronic structure changes at the edges of the 2D crystal result in strong resonant nonlinear optical susceptibilities, allowing direct optical imaging of the atomic edges and boundaries of a 2D material. Using the symmetry of the nonlinear optical responses, we developed a nonlinear optical imaging technique that allows rapid and all-optical determination of the crystal orientations of the 2D material at a large scale. Our technique provides a route toward understanding and making use of the emerging 2D materials and devices.
The Vinylogous Intramolecular Morita−Baylis−Hillman Reaction: Synthesis of Functionalized Cyclopentenes and Cyclohexenes with Trialkylphosphines as Nucleophilic Catalysts

The development of the vinylogous intramolecular Morita−Baylis−Hillman reaction for the synthesis of functionalized cyclopentenes and cyclohexenes is described. The reaction involves the trialkyphosphine-catalyzed cyclization of 1,6- or 1,7-diactivated 1,5-hexadienes or 1,6-heptadienes, containing carboxyaldehyde, methyl ketone, or methoxycarbonyl as the olefin activating groups. A representative example of this reaction is the Me3P-catalyzed cyclization of 1a in tert-amyl alcohol, which provides the substituted cyclopentene 2a in 95% yield and with 97:3 regioselectivity.
S-brane thermodynamics

The description of string-theoretic s-branes at gs = 0 as exact worldsheet CFTs with a ?cosh X0 or ?e?X0 boundary interaction is considered. Due to the imaginary-time periodicity of the interaction under X0?X0+2?i, these configurations have intriguing similarities to black hole or de Sitter geometries. For example, the open string pair production as seen by an Unruh detector is thermal at temperature T = 1/4?. It is shown that, despite the rapid time dependence of the s-brane, there exists an exactly thermal mixed state of open strings. The corresponding boundary state is constructed for both the bosonic and superstring cases. This state defines a long-distance euclidean effective field theory whose light modes are confined to the s-brane. At the critical value of the coupling ? = 1/2, the boundary interaction simply generates an SU(2) rotation by ? from Neumman to Dirichlet boundary conditions. The ? = 1/2 s-brane reduces to an array of sD-branes (D-branes with a transverse time dimension) on the imaginary time axis. The long range force between a (bosonic) sD-brane and an ordinary D-brane is shown from the annulus diagram to be 11/12 times the force between two D-branes. The linearized time-dependent RR field Fp+2 = dCp+1 produced by an sDp-brane in superstring theory is explicitly computed and found to carry a half unit of s-charge Qs = ??8?p*Fp+2 = 1/2, where ?8?p is any transverse spacelike slice.
Reduced Effort Control Laws for Underactuated Rigid Spacecraft

A nonsmooth, time-invariant feedback control law can be used to rotate an axisymmetric rigid spacecraft to the zero equilibriumusingonly twocontroltorques.Thismethod,however, may requireasignie cantamountofcontrol effort, especially for initial conditions close to an equilibrium manifold corresponding to rotations about the unactuated principal axis.Acontrollawisproposedin thiswork thatreducesthecontroleffortrequired toperformrestto-restmaneuversforinitialconditionsclosetothisequilibrium manifold.Specie cally,thephasespaceofthesystem is divided into two parts, one corresponding to initial conditions producing large control effort (the “ bad” region ) and theothercorresponding to initialconditionsproducing small control signals (the“ good” region ). Theproposed control lawthen rendersthisundesirableequilibrium manifold unstable, driving the trajectoriesof theclosed-loop system into the good region, where the original control law is subsequently used. Numerical simulations indicate reduction of the control magnitude on theorder of 80 ‐90% for initial conditions close to theequilibrium manifold.
Asymmetric Synthesis of Hydrobenzofuranones via Desymmetrization of Cyclohexadienones Using the Intramolecular Stetter Reaction

Dearomatization of phenols followed by oxidation affords cyclohexadienyloxyacetaldehydes, which produce hydrobenzofuranones via asymmetric intramolecular Stetter reaction in good to excellent yield. Quaternary as well as up to three contiguous stereocenters may be formed in good to excellent enantioselectivities and high diastereoselectivities.
Rook numbers and the normal ordering problem

For an element w in the Weyl algebra generated by D and U with relation DU = UD + 1, the normally ordered form is w = Σci,j Ui Dj. We demonstrate that the normal order coefficients ci,j of a word w are rook numbers on a Ferrers board. We use this interpretation to give a new proof of the rook factorization theorem, which we use to provide an explicit formula for the coefficients ci,j. We calculate the Weyl binomial coefficients: normal order coefficients of the element (D + U)n in the Weyl algebra. We extend these results to the q-analogue of the Weyl algebra. We discuss further generalizations using i-rook numbers.
Continuous family groupoids.

In this paper, we define and investigate the properties of continuous family groupoids. This class of groupoids is necessary for investigating the groupoid index theory arising from the equivariant Atiyah-Singer index theorem for families, and is also required in noncommutative geometry. The class includes that of Lie groupoids, and the paper shows that, like Lie groupoids, continuous family groupoids always admit (an essentially unique) continuous left Haar system of smooth measures. We also show that the action of a continuous family groupoid G on a continuous family G-space fibered over another continuous family Gspace Y can always be regarded as an action of the continuous family � !
ArF lithography reticle crystal growth contributing factors

The formation of photoinduced crystals and haze has become a challenge for 193nm photolithography high volume manufacturing (1-6). Extensive work has been performed to develop alternative to piranha chemistry for photomask cleaning processes in an attempt to eliminate the incidence of clean induced ammonium sulfate crystal formation (9-13). However, additional factors are impacting 193nm reticle optical quality. Sources of molecular contaminants such as environmental factors, outgasing from pellicle and reticle storage material can generate varieties of photoinduced crystals over the reticle useable lifetime (5-6). This paper will quantify and rank contributing factors for crystals generated under high energy UV exposure. A broad range of analytical and metrology techniques (FTIR, IC, TD-GC/MS, Inorganics impinger, AIMSTM, KLA Starlight, UV 172nm) and improvements in technique sensitivity were developed in order to identify crystal structure, quantify photogenerated contaminants levels and assess wafer printability impact. Engineering systems aimed at minimizing organic and inorganic molecular contaminants levels will be suggested.