cssi/SciSciGPT-SciSciNet huggingface dataset:
Semantic transparency and number marking in Arabic and other languages

Every language has its share of odd or idiosyncratic words, expressions, idioms, and collocational ranges for its vocabulary. For example, Arabic has many lexemes, phrases and expressions which use the plural, but which translate into English in the sg. The plural in the datum in question is overtly marked in Arabic, and what it refers to can be explained in terms of the notion of a semantically transparent plurality; e.g., filmu llahajaat (science/NOM/the dialect/PL) 'the science of dialects' = 'dialectology'. Semantic transparency can be defined as a literal cognitive mapping of an idea, thought or concept, or as 'guessability' for the native speaker. Thus, 'eye doctor' is semantically transparent, since native speakers know the meanings of 'eye' and 'doctor'; however, 'ophthalmologist' is semantically opaque since its morphemic parts are not readily discernable. Returning to the notion of'dialectology', from the viewpoint of the logic of semantic and cognitive structure, 'dialectology' studies dialects, usually many dialects - not merely one, and thus the marking of the plural makes logical sense. In other words, the Arabic plural marking instantaneously denotes reference to numerous dialects (in the plural!) - the object of the study of dialectology.
Stability of the lattice formed in first-order phase transitions to matter containing strangeness in protoneutron stars

Well into the deleptonization phase of a core collapse supernova, a first-order phase transition to matter with macroscopic strangeness content is assumed to occur and lead to a structured lattice defined by negatively charged strange droplets. The lattice is shown to crystallize for expected droplet charges and separations at temperatures typically obtained during the protoneutron star evolution. The melting curve of the lattice for small spherical droplets is presented. The one-component plasma model proves to be an adequate description for the lattice in its solid phase with deformation modes freezing out around the melting temperature. The mechanical stability against shear stresses is such that velocities predicted for convective phenomena and differential rotation during the Kelvin-Helmholtz cooling phase might prevent the crystallization of the phase transition lattice. A solid lattice might be fractured by transient convection, which could result in anisotropic neutrino transport. The melting curve of the lattice is relevant for the mechanical evolution of the protoneutron star and therefore should be included in future hydrodynamics simulations.
A generalized broadcasting schema for the mesh structures

Abstract Broadcasting in a network structure is the process of disseminating information from an originating node to the rest of the nodes in the structure, via successive data transmissions between pairs of nodes. In this paper, we propose a family of general broadcasting schemas for the 2d mesh structures that guarantee minimum delivery time at both the node and the structure level. Although it is intended for the traditional store-and-forward model, it also fits some distance sensitive special cases of the more recent wormhole model. Besides several broadcasting efficiency related quantitative properties of such a schema, such as the ratio of the number of nodes that have to deliver the message to both of its neighbors and the total number of the nodes taking part in the broadcasting process, we also study the close connection between this family of schemas and the class of effective routing paths; and discuss the construction of such a schema as guided by a minimal routing path.
Tunable dynamics of microtubule-based active isotropic gels

We investigate the dynamics of an active gel of bundled microtubules (MTs) that is driven by clusters of kinesin molecular motors. Upon the addition of ATP, the coordinated action of thousands of molecular motors drives the gel to a highly dynamical turbulent-like state that persists for hours and is only limited by the stability of constituent proteins and the availability of the chemical fuel. We characterize how enhanced transport and emergent macroscopic flows of active gels depend on relevant molecular parameters, including ATP, kinesin motor and depletant concentrations, MT volume fraction, as well as the stoichiometry of the constituent motor clusters. Our results show that the dynamical and structural properties of MT-based active gels are highly tunable. They also indicate existence of an optimal concentration of molecular motors that maximize far-from-equilibrium activity of active isotropic MT gels.
Born-Regulated Gravity in Four Dimensions

Previous work involving Born-regulated gravity theories in two dimensions is extended to four dimensions. The action we consider has two dimensionful parameters. Black hole solutions are studied for typical values of these parameters. For masses above a critical value determined in terms of these parameters, the event horizon persists. For masses below this critical value, the event horizon disappears, leaving a ``bare mass,'' though of course no singularity.
Penrose Limits and RG Flows

The Penrose-Guven limit simplifies a given supergravity solution into a pp-wave background. Aiming at clarifying its relation to renormalization group flow we study the Penrose-Guven limit of supergravity backgrounds that are dual to non-conformal gauge theories. The resulting backgrounds fall in a class simple enough that the quantum particle is exactly solvable. We propose a map between the effective time-dependent quantum mechanical problem and the RG flow in the gauge theory. As a testing ground we consider explicitly two Penrose limits of the infrared fixed point of the Pilch-Warner solution. We analyze the corresponding gauge theory picture and write down the operators which are the duals of the low lying string states. We also address RG flows of a different nature by considering the Penrose-Guven limit of a stack of N Dp-branes. We note that in the far IR (for p < 3) the limit generically has negative mass2. This phenomenon signals, in the world sheet picture, the necessity to transform to another description. In this regard, we consider explicitly the cases of M2 from D2 and F1 from D1.
The Ptolemaic gamma-ray burst universe

The BATSE experiment on GRO has demonstrated the isotropic arrival directions and flad logN vs logS of cosmic gamma-ray bursts. These data are best explained if the burst sources are distributed throughout an extended spherical galactic halo, as previously suggested by Jennings. The halo's radius is at least 40 kpc, and probably is more than 100 kpc. I consider possible origins of this halo, including primordial formation and neutron stars recoiling from their birthplaces in the galactic disc A simple geometrical model leads to a predicted relation between the dipole and quadrupole anisotropy. I suggest that neutron stars born with low recoil become millisecond publsars, while those born with high recoil become the sources of gamma-ray bursts; these populations are nearly disjoint. Quiescent counterparts of gamma-ray bursts are predicted to be undetectably faint.
Test of the gravitomagnetic field via laser-ranged satellites

We describe a new experiment to measure the gravitomagnetic field of the Earth. This field, a consequence of the general relativistic formulation of Mach's principle (WEM—Wheeler-Einstein-Mach principle), has never been detected. The idea is to measure the Lense-Thirring precession of the nodal lines of two laser-ranged satellites with supplementary inclinations. In this way it is possible to separate the relativistic nodal precession from the classical nodal precession due to the multipole moments of the Earth.
TESTING HOLOMORPHY ON CURVES

For a domain D ⊂ ℝn we construct a continuous foliation of D into one-real-dimensional curves such that any function f ∈ C1(D) which can be extended holomorphically into some neighborhood of each curve in the foliation will be holomorphic on D.
Shock Breakout in Core-Collapse Supernovae and Its Neutrino Signature

We present results from dynamical models of core-collapse supernovae in one spatial dimension, employing a newly developed Boltzmann neutrino radiation transport algorithm, coupled to Newtonian Lagrangian hydrodynamics and a consistent high-density nuclear equation of state. The transport method is multigroup, employs the Feautrier technique, uses the tangent-ray approach to resolve angles, is implicit in time, and is second-order accurate in space. We focus on shock breakout and follow the dynamical evolution of the cores of 11, 15, and 20 M☉ progenitors through collapse and the first 250 ms after bounce. The shock breakout burst is the signal event in core-collapse evolution, is the brightest phenomenon in astrophysics, and is largely responsible for the initial debilitation and stagnation of the bounce shock. As such, its detection and characterization could test fundamental aspects of the current collapse/supernova paradigm. We examine the effects on the emergent neutrino spectra, light curves, and mix of species (particularly in the early postbounce epoch) of artificial opacity changes, the number of energy groups, the weak magnetism/recoil corrections, nucleon-nucleon bremsstrahlung, neutrino-electron scattering, and the compressibility of nuclear matter. Furthermore, we present the first high-resolution look at the angular distribution of the neutrino radiation field both in the semitransparent regime and at large radii and explore the accuracy with which our tangent-ray method tracks the free propagation of a pulse of radiation in a near vacuum. Finally, we fold the emergent neutrino spectra with the efficiencies and detection processes for a selection of modern underground neutrino observatories and argue that the prompt electron-neutrino breakout burst from the next galactic supernova is in principle observable and usefully diagnostic of fundamental collapse/supernova behavior. Although we are not in this study focusing on the supernova mechanism per se, our simulations support the theoretical conclusion (already reached by others) that spherical (one-dimensional) supernovae do not explode when good physics and transport methods are employed.
Electronic and optical properties of SbSBr, SbSI and SbSeI

Abstract Band structures of SbSBr and SbSeI have been obtained by using the empirical pseudopotential method (EPM) to fit our measured optical reflectivity data and earlier gap measurements. An SbSI band structure has been determined by fitting to earlier reflectivity and Raman spectroscopic data, and the results agree better with the data than do the results of an earlier preliminary EPM calculation. Secondary conduction band minima may in part be responsible for the observed microwave oscillation (Gunn effect) in SbSI. Similar minima in SbSBr and SbSeI are reported, suggesting these crystals might also show microwave properties. The total densities of states are presented.
Assessment of nonequilibrium radiation computation methods for hypersonic flows

The present understanding of shock-layer radiation in the low density regime, as appropriate to hypersonic vehicles, is surveyed. Based on the relative importance of electron excitation and radiation transport, the hypersonic flows are divided into three groups: weakly ionized, moderately ionized, and highly ionized flows. In the light of this division, the existing laboratory and flight data are scrutinized. Finally, an assessment of the nonequilibrium radiation computation methods for the three regimes in hypersonic flows is presented. The assessment is conducted by comparing experimental data against the values predicted by the physical model.
Performance regions in compressed sensing from noisy measurements

In this paper, compressed sensing with noisy measurements is addressed. The theoretically optimal reconstruction error is studied by evaluating Tanaka's equation. The main contribution is to show that in several regions, which have different measurement rates and noise levels, the reconstruction error behaves differently. This paper also evaluates the performance of the belief propagation (BP) signal reconstruction method in the regions discovered. When the measurement rate and the noise level lie in a certain region, BP is suboptimal with respect to Tanaka's equation, and it may be possible to develop reconstruction algorithms with lower error in that region.
Geometrization of 3-dimensional Coxeter orbifolds and Singer’s conjecture

Associated to any Coxeter system (W, S), there is a labeled simplicial complex L and a contractible CW-complex Σ L (the Davis complex) on which W acts properly and cocompactly. Σ L admits a cellulation under which the nerve of each vertex is L. It follows that if L is a triangulation of $${\mathbb{S}^{n-1}}$$ , then Σ L is a contractible n-manifold. In this case, the orbit space, K L := Σ L /W, is a Coxeter orbifold. We prove a result analogous to the JSJ-decomposition for 3-dimensional manifolds: Every 3-dimensional Coxeter orbifold splits along Euclidean suborbifolds into the characteristic suborbifold and simple (hyperbolic) pieces. It follows that every 3-dimensional Coxeter orbifold has a decomposition into pieces which have hyperbolic, Euclidean, or the geometry of $${\mathbb{H}^2\,\times\,\mathbb{R}}$$ . (We leave out the case of spherical Coxeter orbifolds.) A version of Singer’s conjecture in dimension 3 follows: That the reduced l 2-homology of Σ L vanishes.
On Integral Well-rounded Lattices in the Plane

We investigate distribution of integral well-rounded lattices in the plane, parameterizing the set of their similarity classes by solutions of the family of Pell-type Diophantine equations of the form x 2+Dy 2=z 2 where D>0 is squarefree. We apply this parameterization to the study of the greatest minimal norm and the highest signal-to-noise ratio on the set of such lattices with fixed determinant, also estimating cardinality of these sets (up to rotation and reflection) for each determinant value. This investigation extends previous work of the first author in the specific cases of integer and hexagonal lattices and is motivated by the importance of integral well-rounded lattices for discrete optimization problems. We briefly discuss an application of our results to planar lattice transmitter networks.
Sintering TiO2 in HCl Atmospheres

On realise des essais de frittage de TiO 2 en atmosphere de HCl en vue d'accroitre les effets de transport de vapeur. On observe une densification considerablement reduite par rapport a un frittage dans l'air entre 1000° et 1300°C, avec une croissance de grain beaucoup plus rapide. On propose des mecanismes expliquant ces phenomenes
SURVIVAL OF VACCINE VIRUS SEPARATED FROM LIVING HOST CELLS BY COLLODION MEMBRANES.

Vaccine virus, suspended in a mixture of serum and Tyrode's solution and separated by collodion membranes from a suspension of living kidney cells in serum and Tyrode's solution, remained active at 37°C. for a longer period of time than did vaccine virus incubated only in a mixture of serum and Tyrode solution.
Chemical Cartography: Finding the Keys to the Kinetic Labyrinth

Very high resolution lasers allow spectroscopic pictures to be taken following a collision between two molecular reactants. The features of these "pictures" are the electronic, vibrational, rotational, and translational motions of the atomic particles, which relate the quantum states of the reactants to the quantum states of the products. Such state-to-state kinetic information can be used to test the shape and nature of the interaction potential that controls the collision process. The potential itself is akin to a map of the terrain through mountains and valleys where elevation is a measure of energy instead of height. Accurate mapping of this potential surface leads to an understanding of the forces which control rates and mechanisms of chemical reactions. The application of four different advanced laser techniques to the study of collisions between "hot" hydrogen(H) atoms and carbon dioxide(CO2) molecules has provided a wealth of information about both reactive and nonreactive collisions for this system. The availability of data for rotationally, vibrationally, and translationally inelastic excitation of CO2 by H atoms, when compared with data for reactive events producing OH + CO, provides insights into the dynamics of collisions between H and CO2, and illustrates the future promise of these powerful techniques for elucidating features of potential energy surfaces.
Paleoclimatic warming increased carbon dioxide concentrations

[1] If climate-carbon feedbacks are positive, then warming causes changes in carbon dioxide (CO2) sources and sinks that increase CO2 concentrations and create further warming. Previous work using paleoclimatic reconstructions has not disentangled the causal effect of interest from the effects of reverse causality and autocorrelation. The response of CO2 to variations in orbital forcing over the past 800,000 years suggests that millennial-scale climate-carbon feedbacks are significantly positive and significantly greater than century-scale feedbacks. Feedbacks are also significantly greater on 100 year time scales than on 50 year time scales over the past 1500 years. Posterior probability distributions implied by coupled models' predictions and by these paleoclimatic results give a mean of 0.03 for the nondimensional climate-carbon feedback factor and a 90% chance of its being between −0.04 and 0.09. The 70% chance that climate-carbon feedbacks are positive implies that temperature change projections tend to underestimate an emission path's consequences if they do not allow the carbon cycle to respond to changing temperatures.
Characteristic count rate profiles for a rotating modulator gamma-ray imager

Rotating modulation is a technique for indirect imaging in the hard X-ray and soft gamma-ray energy bands, which may offer an advantage over coded aperture imaging at high energies. A rotating modulator (RM) consists of a single mask of co-planar parallel slats typically spaced equidistance apart, suspended above an array of circular non-imaging detectors. The mask rotates, temporally modulating the transmitted image of the object scene. The measured count rate profiles of each detector are folded modulo the mask rotational period, and the object scene is reconstructed using pre-determined characteristic modulation profiles. The use of Monte Carlo simulation to derive the characteristic count rate profiles is accurate but computationally expensive; an analytic approach is preferred for its speed of computation. We present both the standard and a new advanced characteristic formula describing the modulation pattern of the RM; the latter is a more robust description of the instrument response developed as part of the design of a wide-field high-resolution telescope for gamma-ray astronomy. We examine an approximation to the advanced formula to simplify reconstruction software and increase computational speed, and comment on both the inherent limitations and usefulness of the approach. Finally, we show comparisons to the standard formula and demonstrate image reconstructions from Monte Carlo simulations.
ISOMETRIES AND SPECTRA OF MULTIPLICATION OPERATORS ON THE BLOCH SPACE

In this paper, we establish bounds on the norm of multiplication operators on the Bloch space of the unit disk via weighted composition operators. In doing so, we characterize the isometric multiplication operators to be precisely those induced by constant functions of modulus 1. We then describe the spectrum of the multiplication operators in terms of the range of the symbol. Lastly, we identify the isometries and spectra of a particular class of weighted composition operators on the Bloch space.
RADIO CONTINUUM EMISSION IN POLAR RING GALAXIES

We have used the Very Large Array aperture synthesis telescope to conduct a radio continuum survey of polar ring galaxies, at 20 cm and 6 cm. Forty objects were observed at 20 cm with 5'' resolution. Twenty (50%) of the program sources were detected at 20 cm, down to our 5 σ limit of 0.5 mJy beam-1. This detection rate is similar to those in surveys with comparable sensitivity for early-type galaxies without polar rings. Sixteen of the objects we detected at 20 cm were also observed at 6 cm. We show radio continuum maps for the five objects in our sample that have noticeably extended emission. Our spatial resolution was sufficient to distinguish emission originating in the host galaxy from that in the polar ring. The radio morphology of the extended sources, as well as the ratio of radio to far-infrared flux and the radio spectral indices of our detected sources, indicate that star formation, not nuclear activity, is the dominant source of the radio continuum emission in polar ring galaxies. However, the implied star formation rates are modest, and only one of our sample galaxies will consume its supply of cool gas within 500 Myr.
Administering contingent valuation surveys in developing countries

Abstract Ten years ago only a handful of very rudimentary contingent valuation (CV) studies had been conducted in developing countries; at that time the problems associated with posing hypothetical questions to low-income, perhaps illiterate respondents were assumed to be so overwhelming that one should not even try. Today it is now assumed by many environmental and resource economists and policy analysts working in developing countries that contingent valuation surveys are straightforward and easy to do. This paper examines some of the issues that have arisen and some of the lessons learned over the last 10 years about administering contingent valuation surveys in developing countries. The paper focuses on five issues in particular. 1. (a) explaining to enumerators what a contingent valuation study is all about; 2. (b) interpreting responses to contingent valuation questions; 3. (c) setting referendum prices; 4. (d) constructing joint public-private CV scenarios; 5. (e) ethical problems in conducting such surveys. It is argued that there are numerous issues that arise in contingent valuation work in developing countries that demand careful attention, but that in many respects it is easier to do high-quality contingent valuation surveys in developing countries than in industrialized countries.
Effect of sub-Tg annealing on CO2 sorption in polycarbonate

High pressure CO2 sorption data in polycarbonate (PC) are reported as a function of temperature and thermal history. The bulk physical structural changes produced by annealing at 125 and 135°C were monitored by density and thermal property changes. The sorption data are analyzed by the dual sorption model which assumes the sorption isotherm to consist of Henry's law and Langmuir sorption terms; The Langmuir capacity term C of PC can be grossly correlated with the reported volumetric parameters of the polymer. This excess volume interpretation of C has found support in the good correlation between C and the corresponding enthalpy relaxation from parallel Differential Thermal Analysis of the samples. Density measurements provide gross evidence of the free volume interpretation of C. The experimental uncertainties in the data compromise a more critical test of the relationship between C and the density of annealed samples.
Social Network and Weight Misperception among Adolescents

It is recognized that public health intervention targeted toward changing lifestyle behaviors to reduce overweight status is a considerable challenge. It is important that individuals recognize their overweight status as a health risk in order for an effective change in lifestyle behaviors to occur, and growing evidence suggests that actual weight and perception of weight status often do not match, especially among adolescents. In this article, we explore the extent to which exposure to heavier peers and parents affects misperception of their own weight status by adolescents. Using data from a nationally representative sample of adolescents, we estimated instrumental variable models with school-level fixed effects to account for bidirectionality of peer influence and environmental confounders. Our results indicate that individuals who live in an environment that exposes them to overweight/obese parents and heavier peers tend to misperceive their weight status and think of themselves to be of lower weight than they actually are. Our analysis also revealed differential effects by gender and type of peers.
The preparation of optically active δ2- isoxazolines. A model for asymmetric induction in the non lewis acid catalyzed reactions of oppolzer's chiral sultam

Abstract Good diastereoselectivity (ca. 90 10 ) is reported in the cycloaddition reactions of Oppolzer's chiral sultam with nitrile oxides. A model is proposed which may apply to other non Lewis acid promoted reactions of this sultam.
The second Gelfand-Dickey bracket as a bracket on a Poisson-Lie Grassmannian

We introduce a Poisson structure on a Grassmannian Grk(V) on which the Poisson-Lie group GL(V) acts in a Poisson-Lie way. We discuss the analytic complications connected with the infinite-dimensional caseV=C∞(ℝ) and show that an open subset of Grk(V) with this Poisson structure is isomorphic to the Gelfand-Dickey manifold of differential operators of orderk with the second Gelfand-Dickey bracket. In fact we introduce as a consequence a Poisson-Lie action of an enormous group on the Gelfand-Dickey manifold generalizing (on the semiclassical level) the Sugavara inclusion.
Flows Between Rotating Cylinders With a Porous Lining

Flow and temperature fields in an annulus between two rotating cylinders have been examined in this study. While the outer cylinder is stationary, the inner cylinder is rotating with a constant angular speed. A homogeneous and isotropic porous layer is press fit to the inner surface of the outer cylinder. The porous sleeve is saturated with the fluid that fills the annulus. The Brinkman-extended Darcy equations are used to model the flow in the porous layer while the Navier–Stokes equations are used for the fluid layer. The conditions applied at the interface between the porous and fluid layers are the continuity of temperature, heat flux, tangential velocity, and shear stress. Analytical solutions have been attempted. Through these solutions, the effects of Darcy number, Brinkman number, and porous sleeve thickness on the velocity profile and temperature distribution are studied.
Atherosclerosis and the vascular biology of aging

With advancing age, a series of structural, architectural and compositional modifications take place in the vasculature. The diameter of the vessels tends to increase, and thickening of intimal and medial layers is often observed. In the subendothelial space, blood-derived leukocytes and an increased amount of “activated” smooth muscle cells are present. Extracellular matrix accumulates and becomes particularly rich in glycosaminoglycans. Collagen content increases, while elastin fibers appear progressively disorganized, thinner, and frequently fragmented. These changes in the normal architecture of the vessel wall, that could be referred to as “the vasculopa-thy of aging”, are likely to be the consequence of adaptive mechanisms to maintain normal conditions of flow, mechanical stress and/or wall tension. Although many of these features are similar to the histological findings of the atherosclerotic vessels, atherosclerosis and age-related “vasculopathy” are two distinct phenomena. Nonetheless, several experimental observations in animal models suggest a special link between “the vascu-lopathy of aging” and atherosclerotic disease, and suggest a particular predisposition of the old vessel to develop the atherosclerotic lesion. Compared to vessels from young animals, older ones show a greater reactivity to mechanical injury and to chronic insults. This may reflect changes in the biology of the vessels that are “intrinsic” to the aging process. Indeed, aging affects the function and responsiveness of the endothelium and vascular smooth muscle cells. Endothelial permeability is increased with age, while ability to produce vasoactive substances declines. Smooth muscle cells from old individuals show a growth advantage over the young ones, and display an increased ability to migrate toward chemoattractants. Moreover, the accumulation of advanced glycation end products (AGEs) occurring with aging can trigger a series of cellular events, such as cellular oxidative stress, expression of leukocyte adhesion molecules, endothelial transmigration of monocytes, and smooth muscle cell chemotaxis, all considered important prelesional events in the atherogenesis process. Taken together, the changes occurring with aging, while unproven to initiate lesion formation per se, are likely to accelerate the development of the atherosclerotic plaque and contribute to increased severity of this disease in the elderly.
An Interpretation of Cosmic-Ray Phenomena

Schindler's data on the transition effects of the cosmic rays have been interpreted on the assumption that the equilibrium between the primary radiation and its secondary corpuscular rays is different in different media. The ionization behind any thickness of absorbing materials, assumed to be proportional to the flux of secondaries, is calculated in terms of the absorption coefficients, $\ensuremath{\nu}(m)$, of the primary radiation and the production and absorption coefficients, $\ensuremath{\beta}(m)$ and $\ensuremath{\mu}(m, m)$, respectively, of the secondary rays, these coefficients being characteristics of the media. A comparison with the data permits a determination of each of the absorption coefficients as well as the product of each of the production coefficients by the number of primary rays. The results are as follows, expressed in ${\mathrm{cm}}^{\ensuremath{-}1}$ lead equivalent: $\ensuremath{\nu}(\mathrm{Pb})=0.0064$; $\ensuremath{\nu}(\mathrm{Fe})=0.009$; $\ensuremath{\mu}(\mathrm{P}\mathrm{b},\phantom{\rule{0ex}{0ex}}\mathrm{a}\mathrm{i}\mathrm{r})$, the absorption coefficient in lead for secondaries produced in air=0.50; $\ensuremath{\mu}(\mathrm{P}\mathrm{b},\phantom{\rule{0ex}{0ex}}\mathrm{P}\mathrm{b})=0.98$; $\ensuremath{\mu}(\mathrm{F}\mathrm{e},\phantom{\rule{0ex}{0ex}}\mathrm{a}\mathrm{i}\mathrm{r})=0.30$; $\ensuremath{\mu}(\mathrm{F}\mathrm{e},\phantom{\rule{0ex}{0ex}}\mathrm{F}\mathrm{e})=0.45$; $\ensuremath{\mu}(\mathrm{P}\mathrm{b},\phantom{\rule{0ex}{0ex}}\mathrm{F}\mathrm{e})=0.72$; $\ensuremath{\mu}(\mathrm{F}\mathrm{e},\phantom{\rule{0ex}{0ex}}\mathrm{P}\mathrm{b})=0.48$; $\frac{\ensuremath{\beta}(\mathrm{Pb})}{\ensuremath{\beta}(\mathrm{Fe})}=2.0$. This determination of the absorption coefficients of the primary and secondary radiations allows the following estimates to be made. (a) The lower limit of the average energy of the secondary radiation is about 30 million volts. (b) The average number of secondaries per primary is about 100 in iron and 230 in lead. (c) The energy of a primary cosmic ray, equal to the sum of the energies of its secondaries, is about 2\ifmmode\times\else\texttimes\fi{}${10}^{10}$ volts.
Inverse productivity: land quality, labor markets, and measurement error

Abstract This paper examines the role that land quality and imperfect markets play in generating the inverse productivity relationship in the International Crop Research Institute for the Semi Arid Tropics (ICRISAT) data. Differences in land quality largely explain the “Inverse Productivity” (IP) relationship in the random effects profit regression, but not in labor demand regressions. Controlling for labor and land market failures and differences in soil quality eliminates the IP relationship for male labor, but not female labor in the random effects estimates. The inverse relationship is much stronger in fixed effects than random effects estimates, suggesting that the farm size variable may be subject to measurement error, a view supported by the results of instrumental variables estimation.
An empirical analysis of the use of money orders, the payment system of the poor

Abstract Although money orders have been available in the United States since the Civil War, until the mid 1970's and the failure of United States Navigation Company and Universal Money Orders, there had been little analysis of the money order market. This study empirically investigates the determinants of money order usage by households. The results of the study, which utilizes two large national samples, indicate that money orders are clearly an inferior good which have a high probability of being purchased by a low income, young, ethnic minority.
Reduction of hysteresis for carbon nanotube mobility measurements using pulsed characterization

We describe a pulsed measurement technique for suppressing hysteresis for carbon nanotube (CNT) device measurements in air, vacuum, and over a wide temperature range (80-453 K). Varying the gate pulse width and duty cycle probes the relaxation times associated with charge trapping near the CNT, found to be up to the 0.1-10 s range. Longer off times between voltage pulses enable consistent, hysteresis-free measurements of CNT mobility. A tunneling front model for charge trapping and relaxation is also described, suggesting trap depths up to 4-8 nm for CNTs on SiO2. Pulsed measurements will also be applicable for other nanoscale devices such as graphene, nanowires, or molecular electronics, and could enable probing trap relaxation times in a variety of material system interfaces.
Effect of water chemistry on the erosion-corrosion of aluminum in high temperature high velocity water

Abstract Laboratory experiments were conducted to simulate the erosion-corrosion of aluminum fuel cladding in water-cooled, plutonium producing, nuclear reactors. Water quality was demonstrated to be critical in causing erosion-corrosion attack on aluminum in high temperature pressurized water. Very little attack occurred in distilled water, whereas attack was progressively worse in river water and well water. The extreme attack in well water was simulated by dissolving 50 ppm CaCO3 and 10 ppm SiO2 in distilled water. A distinct corrosion enhancing synergism was apparent between dissolved bicarbonate and silicate ions. In situ recordings of electrochemical potential vs time were characteristic of the extent of erosion-corrosion which was occurring on a particular specimen. Polarization resistance measurements did not have the expected sensitivity to erosion-corrosion, probably because of the complex cell geometry imposed by the erosion-corrosion testing apparatus.
Crystallization kinetics of a solid oxide fuel cell seal glass by differential thermal analysis

Abstract Crystallization kinetics of a barium–calcium aluminosilicate glass (BCAS), a sealant material for planar solid oxide fuel cells (SOFC), have been investigated by differential thermal analysis (DTA). From variation of DTA peak maximum temperature with heating rate, the activation energy for glass crystallization was calculated to be 259 kJ/mol using a kinetic model. Development of crystalline phases on thermal treatments of the glass at various temperatures has been followed by powder X-ray diffraction. Microstructure and chemical composition of the crystalline phases were investigated by scanning electron microscopy and energy dispersive spectroscopic (EDS) analysis. BaSiO 3 and hexacelsian (BaAl 2 Si 2 O 8 ) were the primary crystalline phases whereas monoclinic celsian (BaAl 2 Si 2 O 8 ) and (Ba x Ca y )SiO 4 were also detected as minor phases. Needle-shaped BaSiO 3 crystals are formed first, followed by the formation of other phases at longer times of heat treatments. The glass does not fully crystallize even after long-term heat treatments at 750–900 °C. Devitrification of the glass seal over a long period of time during operation of the SOFC would generate thermal stresses in the seal and may have adverse effects on its mechanical performance. This may lead to cracking of the seal, resulting in mixing of the fuel and the oxidant gases.
A context-aware cross-layer broadcast model for ad hoc networks

The standard 802.11 medium access control (MAC) performs poorly for heavy broadcast traffic. We present our context-aware cross-layer (CACL) broadcast model as an alternative. The basic CACL model uses only contextual data available to the 802.11 MAC and so is usable by any routing protocol that uses the 802.11 MAC. CACL fits the total broadcasts in any two-hop neighborhood to wireless channel capacity. We compare collision rates for CACL and the 802.11 MAC and conclude that, for a wide range of network conditions, CACL offers superior single-hop transmission rates. We also present a geographically constrained extension to CACL, CACL-G and compare it against CACL in vehicular scenarios of varying node density. Our results show that CACL-G offers increasingly superior performance over the basic CACL model as node density increases.
Methyltrioxorhenium-catalyzed epoxidations in ionic liquids

Alkenes and allylic alcohols have been epoxidized in an ambient-temperature ionic liquid for the first time using methyltrioxorhenium (MTO) and urea hydrogen peroxide; excellent conversions and selectivities for the epoxides of a wide number of substrates were observed.
When both states and markets fail: asymmetric information and the role of NGOs in African health care

Abstract In African health care the “miracle of the market” has not occurred. Patients exhibit willingness to pay for quality health care and yet good private practitioners are unable to sell their services. Simultaneously nongovernmental organizations (NGOs) are running successful health facilities for which patients are willing to pay. We use a model of the demand for health care in the presence of asymmetric information that allows us to view African health care in the framework of the New Institutional Economics literature. We validate this view empirically and show that NGOs have the institutional capacity to deliver high quality health care. We show that at the same time, neither private practitioners nor regular government organizations charging fees will easily succeed.
The detachment and maturation of conserved lambda prophage DNA

Isotopically labeled Escherichia coli cells lysogenic for phage λ were infected with phage 434hy. Among the resulting phage progeny there was found a class of λ phages containing DNA made predominantly before infection. Experiments are presented which indicate that this DNA is attached to the bacterial chromosome before infection with 434hy. It is argued that the lysogenized bacterial chromosome contains a complete λ chromosome which may be detached and matured intact.
Do high interest rates defend currencies during speculative attacks

Abstract Do high interest rates defend currencies during speculative attacks? Or do they have the perverse effect of increasing the probability of a devaluation of the currency under attack? Drawing on evidence from a large sample of speculative attacks in developed and developing economies, this paper argues that the answer to both questions is ‘no’. In particular, this paper documents a striking lack of any systematic association whatsoever between interest rates and the outcome of speculative attacks. The lack of clear empirical evidence on the effects of high interest rates during speculative attacks mirrors the theoretical ambiguities on this issue.
Markov Switching in GARCH Processes and Mean-Reverting Stock-Market Volatility

This article introduces four models of conditional heteroscedasticity that contain Markov-switching parameters to examine their multiperiod stock-market volatility forecasts as predictions of options-implied volatilities. The volatility model that best predicts the behavior of the options-implied volatilities allows the Student-t degrees-of-freedom parameter to switch such that the conditional variance and kurtosis are subject to discrete shifts. The half-life of the most leptokurtic state is estimated to be a week, so expected market volatility reverts to near-normal levels fairly quickly following a spike.
Microstructure Integrated Modeling of Multiscan Laser Forming

Laser forming of steel is a hot forming process with high heating and cooling rate, during which strain hardening, dynamic recrystallization, and phase transformation take place. Numerical models considering strain rate and temperature effects only usually give unsatisfactory results when applied to multiscan laser forming operations. This is mainly due to the inadequate constitutive models employed to describe the hot flow behavior. In this work, this limitation is overcome by considering the effects of microstructure change on the flow stress in laser forming processes of low carbon steel. The incorporation of such flow stress models with thermal mechanical FEM simulation increases numerical model accuracy in predicting geometry change and mechanical properties.
Scattering of several multiply charged extremal D = 5 black holes

Abstract The moduli space metric for an arbitrary number of extremal D = 5 black holes with arbitrary relatively supersymmetric charges is found.
Complex/Symplectic Mirrors

We construct a class of symplectic non-Kaehler and complex non-Kaehler string theory vacua, extending and providing evidence for an earlier suggestion by Polchinski and Strominger. The class admits a mirror pairing by construction. Comparing hints from a variety of sources, including ten-dimensional supergravity and KK reduction on SU(3)-structure manifolds, suggests a picture in which string theory extends Reid's fantasy to connect classes of both complex non-Kaehler and symplectic non-Kaehler manifolds.
Automated direct patterned-wafer inspection

A self-reference technique is developed for detecting the location of defects in repeated pattern wafers and masks. The application area of the proposed method includes inspection of memory chips, shift registers, switch capacitors, CCD arrays, and liquid crystal displays (LCD). Using high resolution spectral estimation algorithms, the proposed technique first extracts the period and structure of repeated patterns from the image to sub-pixel resolution, and then produces a defect-free reference image for making comparison with the actual image. Since the technique acquires all its needed information from a single image, there is no need for a database image, a scaling procedure, or any a-priori knowledge about the repetition period of the patterns. Results of applying the proposed technique to real images from microlithography are presented.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
The child in epileptic status

Status epilepticus (SE) can be defined as a condition in which a patient has a seizure or cluster of seizures that last for more than 30 minutes without them regaining consciousness? Previous definitions cited a duration of 60 minutes and it is possible that in the future a shorter duration may become a more acceptable practical definition. The justification for using a shorter duration is because treatment should not be withheld until the '30 minute watershed' has been reached. In any individual who has a seizure, there is the potential for a continuum of seizure activity with SE at the severe end. It is well-recognized that, the longer the duration of the seizure, the more difficult it is to stop it. Therefore, the clear, and pragmatic, approach would be to attempt to terminate the seizure as soon as possible and realistically the minimum period within which this could be achieved would be 5 minutes. It is important to emphasize that any seizure type may develop into SE, although generalized tonicclonic (convulsive) is the most common and most serious type. The current classification of SE is as follows:
Flutter analysis of propfans using a three-dimensional Euler solver

A three-dimensional aeroelastic solver is developed and applied to investigate the flutter of a propfan. The unsteady airloads are obtained by solving three-dimensional Euler equations. An implicit-explicit hybrid scheme is used to reduce computational time for the solution of Euler equations. A finite element model is used to obtain structural properties, and a deforming grid technique is used to simulate elastic deformations of the blade. The aeroelastic equations are formulated in normal mode form and are solved for flutter using both the time and frequency domain methods. The analysis is used to calculate the dynamic aeroelastic stability of a single-rotation propfan model for which classical flutter was measured at subsonic relative flows. Comparisons with the experimental data and other calculated results are given.
Early Retirement in the Government Sector in Egypt: Preferences, Determinants, and Policy Implications

This study looks at factors affecting the decision of early retirement for Egyptian government sector employees. The empirical analysis is based on 2005 nationally representative sample of government sector workers. Among the findings of this study are: women are more likely to retire earlier than men; good health status is associated with longer stay on the job; the level of education is not a determining factor for women, but it is for men; men plan to work after their early retirement; the presence of the working wife has a positive effect on her husband to retire early, yet a working husband discourages his wife from retiring early. Policy implications discussed timing of the announcement of the plans; the potential outcome of excessive payouts, as well as the need for the government to provide early retirees with necessary skills and training to plan their after retirement years.
An econometric analysis of veterans' health care utilization using two-part models

Based on the 1992 US National Survey of Veterans, we analyzed veterans’ inpatient and outpatient health care utilization patterns by estimating count data two-part hurdle models. We also identified factors that affect veterans’ choice of health care between VA and non-VA facilities using count data selection models. Not surprisingly, we found that health condition measures are the most important factors in determining veterans’ health care utilization. Gender, disability, and employment status are also significant. Veterans with lower socio-economic status, without other health insurance coverages, or living near VA health care facilities are more likely to use VA health care system for outpatient visits and inpatient admissions. Our study underscores the role of alternative sources of health care and insurance in discerning the true effects of the explanatory variables on an individual’s total demand for health care and its allocation between alternative providers.