cssi/SciSciGPT-SciSciNet huggingface dataset:
Adaptive Bayesian density regression for high-dimensional data

Density regression provides a flexible strategy for modeling the distribution of a response variable Y given predictors X = (X1 ,...,X p) by letting that the conditional density of Y given X as a completely unknown function and allowing its shape to change with the value of X. The number of predictors p may be very large, possibly much larger than the number of observations n, but the conditional density is assumed to depend only on a much smaller number of predictors, which are unknown. In addition to estimation, the goal is also to select the important predictors which actually affect the true conditional density. We consider a nonparametric Bayesian approach to density regression by constructing a random series prior based on tensor products of spline functions. The proposed prior also incorporates the issue of variable selection. We show that the posterior distribution of the conditional density contracts adaptively at the truth nearly at the optimal oracle rate, determined by the unknown sparsity and smoothness levels, even in the ultra highdimensional settings where p increases exponentially with n. The result is also extended to the anisotropic case where the degree of smoothness can vary in different directions, and both random and deterministic predictors are considered. We also propose a technique to calculate posterior moments of the conditional density function without requiring Markov chain Monte Carlo methods.
Significant enhancement of compositional and superconducting homogeneity in Ti rather than Ta-doped Nb3Sn

Nb3Sn wire is now very close to its final optimization, but despite its classical nature, a detailed understanding of the role of Ta and Ti doping in the A15 is not fully developed. Long thought to be essentially equivalent in their influence on Hc2, they were interchangeably applied. Here, we show that Ti produces significantly more homogeneous chemical and superconducting properties. Despite Ta-doped samples having a slightly higher Tc onset in zero-field, they always have a wider Tc-distribution. In particular, whereas the Ta-doped A15 has a Tc-distribution extending from 18 down to 5–6 K (the lowest expected Tc for the binary A15 phase), the Ti-doped samples have no A15 phase with Tc below ∼12 K. The much narrower Tc distribution in the Ti-doped samples has a positive effect on their in-field Tc-distribution too, leading to an extrapolated μ0Hc2(0) 2 T larger than the Ta-doped wire. Ti-doping also appears to be very homogeneous even when the Sn content is reduced in order to inhibit breakdown of the d...
Boosted HCCI for High Power without Engine Knock and with Ultra-Low NOx Emissions - using Conventional Gasoline

The potential of boosted HCCI for achieving high loads has been investigated for intake pressures (P in) from 100 kPa (naturally aspirated) to 325 kPa absolute. Experiments were conducted in a single-cylinder HCCI research engine (0.98 liters) equipped with a compression-ratio 14 piston at 1200 rpm. The intake charge was fully premixed well upstream of the intake, and the fuel was a research-grade (R+M)/2 = 87-octane gasoline with a composition typical of commercial gasolines. Beginning with P in = 100 kPa, the intake pressure was systematically increased in steps of 20 - 40 kPa, and for each P in, the fueling was incrementally increased up to the knock/stability limit, beyond which slight changes in combustion conditions can lead to strong knocking or misfire. A combination of reduced intake temperature and cooled EGR was used to compensate for the pressure-induced enhancement of autoignition and to provide sufficient combustion-phasing retard to control knock. The maximum attainable load increased progressively with boost from a gross indicated mean effective pressure (IMEP g) of about 5 bar for naturally aspirated conditions up to 16.34 bar for P in = 325 kPa. For this high-load point, combustion and indicated thermal efficiencies were 99% and 47%, respectively, and NOx emissions were < 0.1 g/kg-fuel. Maximum pressure-rise rates were kept sufficiently low to prevent knock, and the COV of the IMEP g was < 1.5%. Central to achieving these results was the ability to retard combustion phasing (CA50) as late as 19°after TDC with good stability under boosted conditions. Detailed examination of the heat release rates shows that this substantial CA50 retard was possible because intake boosting significantly enhances the early autoignition reactions, keeping the charge temperature rising toward the hot-ignition point despite the high rate of expansion at these late crank angles. Overall, the investigation showed that well-controlled boosted HCCI has a strong potential for achieving power levels close to those of turbo-charged diesel engines. Copyright © 2010 SAE International.
Anisotropy of transverse sound in the heavy fermion superconductor UPt3.

We report the first measurements of the attenuation of ultrasound in the basal plane of superconducting UPt3. Transverse sound propagating along the b axis shows a marked anisotropy in its temperature dependence when the polarization is rotated in and out of the basal plane. For polarization in the basal plane the attenuation varies linearly with temperature down to 35 mK and the slope scales as the square of the frequency. Our results appear to indicate the presence of an additional attenuation mechanism when compared with recent theories of anisotropic superconductors in the dirty limit.
Almost Global Existence for the Prandtl Boundary Layer Equations

We consider the Prandtl boundary layer equations on the half plane, with initial datum that lies in a weighted H1 space with respect to the normal variable, and is real-analytic with respect to the tangential variable. The boundary trace of the horizontal Euler flow is taken to be a constant. We prove that if the Prandtl datum lies within \({\varepsilon}\) of a stable profile, then the unique solution of the Cauchy problem can be extended at least up to time \({T_{\varepsilon} \geqq {\rm exp}(\varepsilon^{-1} / {\rm log}(\varepsilon^{-1}))}\).
The Chemistry of Organophosphorus Chemical Warfare Agents

1 Introduction 2 Historical Development 3 Synthesis 4 Chemical and Physical Properties 5 Decontamination 6 Spectroscopic Analysis 7 Chromatographic Analysis 8 Trace Analysis of Nerve Agents and their Degradation Products in Verification 9 Generic Detection of Nerve Agents 10 Mechanism of Action 11 Toxicodynamics 12 Therapy and Pretreatment 13 Structure—Toxicity Relationships 14 Control Under the Chemical Weapons Convention Keywords: chemistry of organophosphorus chemical warfare agents; methylphosphonofluoridates; classical methods of synthesis; V-agents; enzyme methods; chemical and physical properties; DFP and Tabun synthesis; Resolution—V-agents, G-agents
On the Extent of Strategic Voting

Social scientists have long speculated about individuals' tendencies to misrepresent their preferences in order to affect the outcome of social choice mechanisms. The fact that preference orderings are generally unobserved, however, has made it very difficult to document strategic behavior empirically. Exploiting the incentive structure of Germany's voting system to solve the fundamental identification problem, this paper estimates the extent of strategic voting in large, real-world elections. The evidence indicates that approximately 35% of voters abandon their most preferred candidate if she is not in contention for victory. As predicted by theory, tactical behavior has a non-trivial impact on individual races. Yet, as one aggregates across districts, these distortions partially offset each other, resulting in considerably more modest effects on the overall distribution of seats.
Generalized discrete timed automata: decidable approximations for safety verification

We consider generalized discrete timed automata with general linear relations over clocks and parameterized constants as clock constraints and with parameterized durations. We look at three approximation techniques (i.e., the r-reset-bounded approximation, the B-bounded approximation, and the 〈B, r〉-crossing-bounded approximation), and derive automata-theoretic characterizations of the binary reachability under these approximations. The characterizations allow us to show that the safety analysis problem is decidable for generalized discrete timed automata with unit durations and for deterministic generalized discrete timed automata with parameterized durations. An example specification written in ASTRAL is used to run a number of experiments using one of the approximation techniques.
Learning multifractal structure in large networks

Using random graphs to model networks has a rich history. In this paper, we analyze and improve the multifractal network generators (MFNG) introduced by Palla et al. We provide a new result on the probability of subgraphs existing in graphs generated with MFNG. This allows us to quickly compute moments of an important set of graph properties, such as the expected number of edges, stars, and cliques for graphs generated using MFNG. Specifically, we show how to compute these moments in time complexity independent of the size of the graph and the number of recursive levels in the generative model. We leverage this theory to propose a new method of moments algorithm for fitting MFNG to large networks. Empirically, this new approach effectively simulates properties of several social and information networks. In terms of matching subgraph counts, our method outperforms similar algorithms used with the Stochastic Kronecker Graph model. Furthermore, we present a fast approximation algorithm to generate graph instances following the multifractal structure. The approximation scheme is an improvement over previous methods, which ran in time complexity quadratic in the number of vertices. Combined, our method of moments and fast sampling scheme provide the first scalable framework for effectively modeling large networks with MFNG.
Completeness of scattering states for rough interfaces

Abstract Using energy conservation and causality considerations, the completeness of scattering states is established for plane waves impinging on an irregular interface. Provided certain limiting operations commute with differentiation, it is shown that surface waves need not be explicity included in the Weyl representation of the Green's function in the presence of a rough interface. Rather, surface waves are implicity included through the poles of the scattering amplitudes. This result was used implicitly in a recently developed scheme to treat scattering in a duct using half-space scattering amplitudes (Berman, J. Acoust. Soc. Am. 92 (1992), 309–314).
1046 A Stool-Based MicroRNA and DNA Marker Panel for the Detection of Pancreatic Cancer

and obese patients without CP (0.13% (47/34323)). Conclusion: Amongst patients with new onset DM, non-obese patients with history of chronic pancreatitis have markedly higher risk of an underlying pancreatic cancer and probably be considered for a definitive test to diagnose pancreatic cancer. Use of this strategy to further enrich the cohort however results in exclusion of the vast majority of pancreatic cancers in NODM patients.
Heading for higher ground: factors affecting real and hypothetical hurricane evacuation behavior

The purpose of this paper is to assess the determinants of hurricane evacuation behavior of North Carolina coastal households during Hurricane Bonnie and a future hypothetical hurricane. We use the data from a telephone survey of North Carolina coastal residents. Hypothetical questions are used to assess whether respondents will evacuate and where in the case of a future hurricane with varying intensities. We examine the social, economic, and risk factors that affect the decisions to evacuate and whether to go to a shelter or motel/hotel relative to other destinations. The most important predictor of evacuation is storm intensity. Households are more likely to evacuate when given evacuation orders, when they perceive a flood risk, and when they live in mobile homes. Households who own pets are less likely to evacuate. Non-white households, pet owners and those with more education are less likely to go to either a motel/hotel or shelter, preferring instead to stay with friends or family.
Deep Mid-Infrared Silicate Absorption as a Diagnostic of Obscuring Geometry toward Galactic Nuclei

The silicate cross section peak near 10 μm produces emission and absorption features in the spectra of dusty galactic nuclei observed with the Spitzer Space Telescope. Especially in ultraluminous infrared galaxies, the observed absorption feature can be extremely deep, as IRAS 08572+3915 illustrates. A foreground screen of obscuration cannot reproduce this observed feature, even at a large optical depth. Instead, the deep absorption requires a nuclear source to be deeply embedded in a smooth distribution of material that is both geometrically and optically thick. In contrast, a clumpy medium can produce only shallow absorption or emission, which are characteristic of optically identified active galactic nuclei. In general, the geometry of the dusty region and the total optical depth, rather than the grain composition or heating spectrum, determine the silicate feature's observable properties. The apparent optical depth calculated from the ratio of line to continuum emission generally fails to accurately measure the true optical depth. The obscuring geometry, not the nature of the embedded source, also determines the far-IR spectral shape.
The Nature of the Ultraluminous Oxygen-Rich Supernova Remnant in NGC 4449

Optical images and spectra, both ground based and taken by Hubble Space Telescope (HST), of the young, luminous O-rich supernova remnant in the irregular galaxy NGC 4449 are presented. HST images of the remnant and its local region were obtained with the ACS/WFC using filters F435W, F555W, F814W (B, V, and I, respectively), F502N ([O III]), F658N (Hα + [N II]), F660N ([N II]), and F550M (line-free continuum). These images show an unresolved remnant (FWHM < 0.05'') located within a rich cluster of OB stars which itself is enclosed by a nearly complete interstellar shell seen best in Hα + [N II] emission approximately 8'' × 6'' (150 pc × 110 pc ) in size. The remnant and its associated OB cluster are isolated from two large nearby H II regions. The ACS [O III] image shows the remnant may be partially surrounded by a clumpy ring of emission approximately 1'' (~20 pc) in diameter. Recent ground-based spectra of the remnant reveal (1) the emergence of broad, blueshifted emission lines of [S II] λλ6716, 6731, [Ar III] λ7136, and [Ca II] λλ7291, 7324 which were not observed in spectra taken in 1978-1980; (2) faint emission at 6540-6605 A centered about Hα and [N II] λλ6548, 6583 with an expansion velocity of 500 ± 100 km s−1; and (3) excess emission around 4600-4700 A suggestive of a Wolf-Rayet population in the remnant's star cluster. We use these new data to re-interpret the origin of the remnant's prolonged and bright luminosity and propose that the remnant is strongly interacting with dense, circumstellar wind loss material from a 20 M☉ progenitor star.
Halo white dwarfs, thick disks and a sanity check

The recent discovery of a population of high proper-motion white dwarfs by Oppenheimer and coworkers has caused a lot of speculation as to the origin of these stars. I show that the age distribution of the white dwarfs offers a kind of sanity check in these discussions. In particular, the majority of the identified population appears to have a similar age distribution to those in the standard, thin-disk white dwarf population. This is not what is expected for either the halo or thick disk, which are thought to be old populations. A subset of the Oppenheimer "halo" sample does indeed possess an age distribution consistent with a halo origin, but the density is smaller and consistent with the results of Gould, Flynn, & Bahcall for a high-end mass function slope of -0.9.
Efficient, Pareto-improving processes

Abstract We give two optimization programs for determining whether Pareto improving local changes are possible. When they are, the programs compute them. Any procedure generating efficient and Pareto improving changes can be replicated by these programs. The two programs are dual to each other. We apply the programs to Pareto improving exchange processes and to Pareto-improving tax-tariff reforms.
Exact results in SO(11) SUSY gauge theories with spinor and vector matter

Abstract We investigate the confining phase vacuum structure of supersymmetric SO (11) gauge theories with one spinor matter field and N f ≤ 6 vectors. We describe several useful tricks and tools that facilitate the analysis of these chiral models and many other theories of similar type. The forms of the N f = 5 and N f = 6 quantum moduli spaces are deduced by requiring that they reproduce known results for SU (5) SUSY QCD along the spinor flat direction. After adding mass terms for vector fields and integrating out heavy degrees of freedom, we also determine the dynamically generated superpotentials in the N f ≤ 4 quantum theories. We close with some remarks regarding magnetic duals to the N f ≥ 7 electric SO (11) theories.
The Spoils of War

In After the Last Sky, Edward Said famously invoked a frequently cited, and frequently disputed, comparison between the Palestinian situation after 1967 and the Jewish situation after the Holocaust...
Quantum Statistical Dynamics of Laser Amplifiers

Abstract : A quantum statistical procedure for analyzing radiation fields interacting with other systems has been developed and applied to a model laser operating as a linear amplifier.
Electrochemical study of gold electrodes with anodic oxide films—II. Inhibition of electrochemical redox reactions by monolayers of surface oxides

Abstract The anodically first formed oxide on gold (oxide I) reaches two complete monolayers, ie 1.5 mC cm −2 oxide charge, before a second type of oxide (oxide II) starts to form. Electrochemical redox reactions with redox couples such as the tris( o -phenantroline) ferrous/ferric ion couple and others which are well known to behave reversibly on bare gold are inhibited completely by gold covered with this critical coverage of two monolayers of oxide I. Up to nearly completion of this two monolayer coverage, the redox reactions behave reversibly. In the transition to the completion of two monolayers the reaction appears to be increasingly irreversible. This behaviour is explained on the basis of diffusion layer thickness, heterogeneous rate constants and the size and distribution of the active bare gold sites as well as of the inhibiting oxide covered sites on the surface. The inhibition by two complete monolayers of gold oxide seems to be of general character for redox couples independent of pH and electrolyte.
Effect of noise on the standard mapping

Abstract The effect of a small amount of noise on the standard mapping is considered. Whenever the standard mapping possesses accelerator modes (where the action increases approximately linearly with time), the diffusion coefficient contains a term proportional to the reciprocal of the variance of the noise term. At large values of the stochasticity parameter, the accelerator modes exhibit a universal behavior. As a result the dependence of the diffusion coefficient on the stochasticity parameter also shows some universal behavior.
Chromatic polynomials, Potts models and all that☆

The q-state Potts model can be defined on an arbitrary finite graph, and its partition function encodes much important information about that graph, including its chromatic polynomial, flow polynomial and reliability polynomial. The complex zeros of the Potts partition function are of interest both to statistical mechanicians and to combinatorists. I give a pedagogical introduction to all these problems, and then sketch two recent results: (a) Construction of a countable family of planar graphs whose chromatic zeros are dense in the whole complex q-plane except possibly for the disc |q−1|<1. (b) Proof of a universal upper bound on the q-plane zeros of the chromatic polynomial (or antiferromagnetic Potts-model partition function) in terms of the graph's maximum degree.
Thermodynamic ionization constants for crown ether carboxylic acids in aqueous dioxane

Abstract Thermodynamic ionization constants have been determined in 70% dioxane-water (by volume) for nine macrocyclic polyether (crown ether) compounds which have pendant carboxylic acid functions. The influence of structural variation within the crown ether carboxylic acid upon the thermodynamic ionization constant is assessed.
High resolution electron microscopy of interfaces in fcc materials

Abstract Modern high-resolution electron microscopy (HREM) instruments, which are capable of a point-to-point resolution of better than 0.2 nm, have allowed atomic-scale observations of a variety of internal interfaces. The application of the HREM technique to fcc model systems for the purpose of addressing a number of interface issues will be examined in this paper. Atomic structure observations for heterophase interfaces of metal/metal and metal/metal-oxide systems as well as HREM studies of grain boundaries in NiO and Au will be discussed with emphasis on generic structural features and the role of the interface plane. Comparisons between observed interface structures and atomistic computer modeling results have shown agreements for some interfaces, and certain differences in others. A number of structural features are common to both metal and oxide grain boundaries, as well as certain heterophase boundaries. Of particular importance in close-packed solids appears to be the tendency to preserve, as much as possible, local atomic coordination, giving rise to atomically well-matched regions that alternate along the interface with regions of misfit. It is commonly observed that heterophase interfaces are preferentially formed on dense-packed planes. Low-index planes are also frequently observed in asymmetric grain boundaries. In addition to the observation of misfit dislocations in heterophase boundaries, misfit-dislocation-like defects have also been found in asymmetric, incommensurate grain boundaries. The tendency for maintaining coherence between dense-packed planes across the interface has resulted in the formation of novel three-dimensional grain boundary structures. HREM observations have brought new insights into the correlations between macroscopic geometry, interfacial energy, and microscopic atomic relaxations.
Standard Oil and Predatory Pricing: Myth Paralleling Fact

The Supreme Court in 1911, on the occasion of the first major test of the Sherman Act, ordered the dissolution of the Standard Oil Trust. In his 1958 paper John McGee argued that predatory pricing is, in general, irrational and, relying solely on the information in the Trial Record related to that decision, concluded that Standard Oil did not engage in predatory pricing. His paper has had an extraordinary influence on both antitrust policy in the United States and economic lore. This paper documents the breadth and scope of the influence of McGee’s paper and offers several possible explanations for it. We suggest four reasons: (1) the lack of a theoretical challenge for 25 years, (2) the failure of scholars to replicate McGee’s empirical findings, (3) the unique status of the Standard Oil case in the history of American antitrust and (4) the influence of the Chicago School on economic and legal thinking.
A unifying model for planform straightness of ripples and dunes in air and water

Abstract Geologists, physicists, and mathematicians have studied ripples and dunes for more than a century, but despite considerable effort, no general model has been proposed to explain perhaps the most fundamental property of their morphology: why are some bedforms straight, continuous, parallel, and uniform in planform geometry (i.e. two-dimensional) whereas others are irregular (three-dimensional)? Here we argue that physical coupling along the crest of a bedform is required to produce straight crests and that along-crest flow and sand transport provide effective physical mechanisms for that coupling. Ripples and dunes with the straightest and most continuous crests include longitudinal and oblique dunes in unidirectional flows, wave ripples, dunes in reversing flows, wind ripples, and ripples migrating along a slope. At first glance, these bedforms appear quite different (ripples and dunes; air and water; transverse, oblique, and longitudinal orientations relative to the net sand-transport direction), but they all have one property in common: a process that increases the amount of along-crest sand transport (that lengthens and straightens their crests) relative to the across-crest transport (that makes them migrate and take the more typical and more three-dimensional planform geometry). In unidirectional flows that produce straight bedforms, along-crest transport of sand is caused by along-crest flow (non-transverse bedform orientation), gravitational transport along an inclined crest, or ballistic splash in air. Bedforms in reversing flows tend to be straighter than their unidirectional counterparts, because reverse transport across the bedform crest reduces the net across-crest transport (that causes the more typical irregular geometry) relative to the along-crest transport (that smoothes and straightens planform geometry).
Aerodynamic design optimization using sensitivity analysis and computational fluid dynamics

An investigation was conducted from October 1, 1990 to May 31, 1994 on the development of methodologies to improve the designs (more specifically, the shape) of aerodynamic surfaces of coupling optimization algorithms (OA) with Computational Fluid Dynamics (CFD) algorithms via sensitivity analyses (SA). The study produced several promising methodologies and their proof-of-concept cases, which have been reported in the open literature.
Channel noise and synchronization in excitable membranes

Using a stochastic generalization of the Hodgkin–Huxley model, we consider the influence of intrinsic channel noise on the synchronization between the spiking activity of the excitable membrane and an externally applied periodic signal. For small patches, i.e., when the channel noise dominates the excitable dynamics, we find the phenomenon of intrinsic coherence resonance. In this case, the relatively regular spiking behavior is practically independent of the applied external driving; therefore no synchronization occurs. Synchronization takes place, however, only for sufficiently large ion channel assemblies. The neuronal signal processing is thus likely rooted in the collective properties of optimally large assemblies of ion channels.
Planning applications in image analysis

We describe two interim results from an ongoing effort to automate the acquisition, analysis, archiving, and distribution of satellite earth science data. Both results are applications of Artificial Intelligence planning research to the automatic generation of processing steps for image analysis tasks. First, we have constructed a linear conditional planner (CPed), used to generate conditional processing plans. Second, we have extended an existing hierarchical planning system to make use of durations, resources, and deadlines, thus supporting the automatic generation of processing steps in time and resource-constrained environments.
Observation of quantum-measurement backaction with an ultracold atomic gas

Current research on micromechanical resonators strives for quantum-limited detection of the motion of macroscopic objects. Prerequisite to this goal is the observation of measurement backaction consistent with quantum metrology limits. However, thermal noise currently dominates measurements and precludes ground-state preparation of the resonator. Here, we establish the collective motion of an ultracold atomic gas confined tightly within a Fabry–Perot optical cavity as a system for investigating the quantum mechanics of macroscopic bodies. The cavity-mode structure selects a particular collective vibrational motion that is measured by the cavity’s optical properties, actuated by the cavity optical field and subject to backaction by the quantum force fluctuations of this field. Experimentally, we quantify such fluctuations by measuring the cavity-light-induced heating of the intracavity atomic ensemble. These measurements represent the first observation of backaction on a macroscopic mechanical resonator at the standard quantum limit. Nanoscale beams are one platform for exploring quantum-mechanical phenomena in ever-larger systems. The collective motion of a macroscopic ensemble of ultracold atoms confined in an optical cavity is established as an alternative approach.
Nonlinear and postbuckling responses of curved composite panels with cutouts

Abstract The results of a detailed study of the nonlinear and postbuckling responses of curved unstiffened composite panels with central circular cutouts are presented. The panels are subjected to applied edge displacements and temperature changes. The analysis is based on a first-order shear-deformation Sanders-Budiansky type theory with the effects of large displacements, moderate rotations, transverse shear deformation and laminated anisotropic material behavior included. A mixed formulation is used with the fundamental unknowns consisting of the generalized displacements and the stress resultants of the panel. The nonlinear displacements, strain energy, transverse shear stresses, transverse shear strain energy density, and their hierarchical sensitivity coefficients are evaluated. The hierarchical sensitivity coefficients measure the sensitivity of the nonlinear response to variations in three sets of interrelated parameters; namely, the panel stiffnesses, the material properties of the individual layers, and the material properties of the constituents (fibers, matrix, interface and interphase). Numerical results are presented for cylindrical panels with central circular cutouts subjected to edge shortening and uniform temperature change, showing the effects of variations in the panel curvature, hole diameter, laminate stacking sequence and fiber orientation, on the nonlinear and postbuckling panel responses, and their sensitivity to changes in the various panel, layer and micromechanical parameters.
Helium abundance variations

Using observations of the solar wind by Explorers 34 and 43, the relationship is confirmed between the relative abundance of helium n sub alpha/n sub p and the bulk speed U of the wind, recently described by Hirschberg, Asbridge and Robbins. Use of this relationship n sub alpha/n sub p = a(t)+bU allows the dependence of the relative abundance of helium upon solar activity to be separated from its bulk speed dependence. The proportion of helium in the solar wind at a given bulk speed is found to increase with increasing sunspot number, averaged over the period of observation. It is shown that the relationship between average relative abundance and temperature, deduced using the bulk speed - temperature relation, is consistent with the data. The relative abundance of helium is not found to increase with increasing solar wind flux. This confirms the result of Hirschberg et al, and contradicts the theoretical prediction of Geiss.
Efficient cost-based scheduling for scalable media streaming

The number of media streams that can be supported concurrently is highly constrained by the stringent requirements of real-time playback and high transfer rates. To address this problem, media delivery techniques, such as Batching and Stream Merging, utilize the multicast facility to increase resource sharing. The achieved resource sharing depends greatly on how the waiting requests are scheduled for service. Scheduling has been studied extensively when Batching is applied, but up to our knowledge, it has not been investigated in the context of stream merging techniques, which achieve much better resource sharing. In this study, we analyze scheduling when stream merging is employed and propose a simple, yet highly effective scheduling policy, called Minimum Cost First (MCF). MCF exploits the wide variation in stream lengths by favoring the requests that require the least cost. We present two alternative implementations of MCF: MCF-T and MCF-P. We compare various scheduling policies through extensive simulation and show that MCF achieves significant performance benefits in terms of both the number of requests that can be serviced concurrently and the average waiting time for service.
MoteTrack: a robust, decentralized approach to RF-based location tracking

In this paper, we present a robust, decentralized approach to RF-based location tracking. Our system, called MoteTrack, is based on low-power radio transceivers coupled with a modest amount of computation and storage capabilities. MoteTrack does not rely upon any back-end server or network infrastructure: the location of each mobile node is computed using a received radio signal strength signature from numerous beacon nodes to a database of signatures that is replicated across the beacon nodes themselves. This design allows the system to function despite significant failures of the radio beacon infrastructure. In our deployment of MoteTrack, consisting of 23 beacon nodes distributed across our Computer Science building, we achieve a 50th percentile and 80th percentile location-tracking accuracy of 0.9 and 1.6 m respectively. In addition, MoteTrack can tolerate the failure of up to 60% of the beacon nodes without severely degrading accuracy, making the system suitable for deployment in highly volatile conditions. We present a detailed analysis of MoteTrack's performance under a wide range of conditions, including variance in the number of obstructions, beacon node failure, radio signature perturbations, receiver sensitivity, and beacon node density.
Mass spectroscopic evidence for the formation of mixed-metal octahedral clusters [MonW6−nCl14]2−

Abstract Mixed-metal clusters containing molybdenum and tungsten have been prepared by reducing MoCl5 and WCl6 with aluminum in a NaClAlCl3 melt. Liquid secondary ion mass spectra of the product indicates the presence of seven-metal clusters across the full range, n=0 to 6 for [MonW6−nCl14]2−. The distribution of molybdenum and tungsten in the clusters is dependent on the Mo/W ratio in the starting melt, and is biased in favor of molybdenum.
On the moduli space of deformations of bihamiltonian hierarchies of hydrodynamic type

We investigate the deformation theory of the simplest bihamiltonian structure of hydrodynamic type, that of the dispersionless KdV hierarchy. We prove that all of its deformations are quasi-trivial in the sense of B. Dubrovin and Y. Zhang, that is, trivial after allowing transformations where the first partial derivative ?u of the field is inverted. We reformulate the question about deformations as a question about the cohomology of a certain double complex, and calculate the appropriate cohomology group.
A search for core-collapse supernova progenitors in Hubble Space Telescope images

ABSTRACT Identifying the massive progenitor stars that give rise to core‐collapse supernovae (SNe) is one of the main pursuits of supernova and stellar evolution studies. Using ground‐based images of recent, nearby SNe obtained primarily with the Katzman Automatic Imaging Telescope, astrometry from the Two Micron All Sky Survey, and archival images from the Hubble Space Telescope, we have attempted the direct identification of the progenitors of 16 Type II and Type Ib/c SNe. We may have identified the progenitors of the Type II SNe 1999br in NGC 4900, 1999ev in NGC 4274, and 2001du in NGC 1365 as supergiant stars with \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \no...
Imaging-based parametric resonance in an optical dipole-atom trap

We report sensitive detection of parametric resonances in a high-density sample of ultracold $^{87}\text{R}\text{b}$ atoms confined to a far-off-resonance optical dipole trap. Fluorescence imaging of the expanded ultracold atom cloud after a period of parametric excitation shows significant modification of the atomic spatial distribution and has high sensitivity compared with traditional measurements of parametrically driven trap loss. Using this approach, a significant shift of the parametric resonance frequency is observed and attributed to the anharmonic shape of the dipole trap potential.
Probabilistic and Other Neural Nets in Multi-Hole Probe Calibration and Flow Angularity Pattern Recognition

The use of probabilistic (PNN) and multilayer feedforward (MLFNN) neural networks is investigated for the calibration of multi-hole pressure probes and the prediction of associated flow angularity patterns in test flow fields. Both types of network are studied in detail for their calibration and prediction characteristics. The current formalism can be applied to any multi-hole probe, however the test results for the most commonly used five-hole Cone and Prism probe types alone are reported in this paper.
Modulatory effects of binocular disparity and aging upon the perception of speed

Abstract Two experiments investigated modulatory effects of a surround upon the perceived speed of a moving central region. Both the surround’s depth and velocity (relative to the center) were manipulated. The abilities of younger observers (mean age was 23.1 years) were evaluated in Experiment 1, while Experiment 2 was devoted to older participants (mean age was 71.3 years). The results of Experiment 1 revealed that changes in the perceived depth of a surround (in this case caused by changes in binocular disparity) significantly influence the perceived speed of a central target. In particular, the center’s motion was perceived as fastest when the surround possessed uncrossed binocular disparity relative to the central target. This effect, that targets that are closer than their background are perceived to be faster, only occurred when the center and surround moved in the same directions (and did not occur when center and surround moved in opposite directions). The results of Experiment 2 showed that the perceived speeds of older adults are different: older observers generally perceive nearer targets as faster both when center and surround move in the same direction and when they move in opposite directions. In addition, the older observers’ judgments of speed were less precise. These age-related changes in the perception of speed are broadly consistent with the results of recent neurophysiological investigations that find age-related changes in the functionality of cortical area MT.
Earth-Based Remote Sensing of Planetary Surfaces And Atmospheres at Radio Wavelengths

Radio observations of the planets are providing much valuable information about these remote environments. Most of these objects are black bodies emitting thermal radiation which appears brighter at short wavelengths but we generally wish to investigate the effects of atmospheric absorption and subsurface heat conduction on them which requires observations using a wide variety of astronomical techniques over a large range of wavelengths. Most parameters change only slowly with wavelength so that continuum radiometry at selected wavelengths is sufficient in most cases. Many of the planetary signals are weak and it is very important to accurately separate their emission from that of the background sky and nearby confusing sources. This involves continuous comparison with the nearby background by various switching, on-off, and scanning techniques plus reobservation of the same spot in the sky after the planet has moved away. Often, over 2/3 of the time required for an observation is actually spent on comparison rather than looking at the actual target planet. Recently, aperture synthesis observations using interferometers have provided very-high-resolution pictures of some of the planets and removed many of the background problems. Another important concern is calibration of the results so we can have accurate values of the absolute temperatures of these bodies. This requires measurement of the antenna parameters and also the effects of the Earth's atmosphere upon the incoming signals.
Asymmetrically filled slits in a metal film that split a light beam into two depending on its wavelength

By applying a scattering-wave theory, the electromagnetic response of an arbitrary array of multiple slits perforated on a metallic film and filled with different slit dielectric materials can be studied in an analytical way. Here, the wavelength-dependent splitting of a light beam into two by asymmetrically filled slits in a metal film using intraslit and interslit dual-wave interferences is fully explored. We consider a triple-slit structure perforated on a gold film, where the middle slit is used for the surface-plasmon (SP) excitation by a narrow Gaussian beam while the two side slits are used for the detection of a transmitted SP wave propagated from the middle opaque slit either at a particular wavelength or at double that wavelength, respectively. For this proposed simple structure, we show that only one of the two side observation slits can be in a passing state for a particular wavelength, but the other blocked slit will change to a passing state at double that wavelength with a specific design for the slit depth, slit dielectric, and interslit distance in the deep subwavelength regime. In this sense, SP mediated light transmission becomes wavelength sensitive in our model, and a single light beam can be separated into two according to its wavelength in the transverse direction parallel to the array. This provides us with a unique way for direct optical reading in the near-field region using a nonspectroscopic approach.
Dual payoff scenario warnings on credit card statements elicit suboptimal payoff decisions

U.S. Federal regulation from 2009 requires credit card companies to convey information regarding payoff scenarios, i.e., details such as total amount paid and time to pay off when only a minimum payment is made (over time). Across seven studies, the present research shows that consumers who were given a dual payoff scenario (i.e., how much is paid in total based on the minimum payment and also based on a 3-year payoff window) on credit card statements recommended lower payments than those given a single payoff scenario (when the 3-year payment amount was less than what they would have paid otherwise), and were less likely to pay off the balance in full. The effect is driven by a tendency of consumers to infer that the 3-year payment amount is the most appropriate. The dual-scenario effect is minimized by an intervention that draws attention away from the 3-year payment amount. Theoretical and public policy implications are considered.
Options and sunspots in a simple monetary economy

We study sunspot immunity in a dynamic monetary economy in which consumers are allowed to trade put and call option contracts on the general price level. We define the concept of strong sunspot immunity to characterize economies that have no sunspot equilibria regardless of the number of extrinsic states and their probabilities of occurrence. We show that a small number of option contracts can make an economy strongly sunspot immune. In addition, we demonstrate how asset re-trading opportunities, and the associated capital gains and losses, reduce the number of options needed for this result to obtain.
Addition–deletion networks

We study structural properties of growing networks where both addition and deletion of nodes are possible. Our model network evolves via two independent processes. With rate r, a node is added to the system and this node links to a randomly selected existing node. With rate 1, a randomly selected node is deleted and its parent node inherits the links of its immediate descendants. We show that the in-component size distribution decays algebraically, ck ~ k−β as k → ∞. The exponent β = 2 + (r − 1)−1 varies continuously with the addition rate r. Structural properties of the network including the height distribution, the diameter of the network, the average distance between two nodes and the fraction of dangling nodes are also obtained analytically. Interestingly, the deletion process leads to a giant hub, a single node with a macroscopic degree whereas all other nodes have a microscopic degree.
Initial Clinical Evaluation of the NovaScan Carbon Dioxide Laser Handpiece

background. This report summarizes an institutional review board-approved 6-month study with the NovaPulse carbon dioxide (CO2) laser utilizing the NovaScan handpiece in facial skin resurfacing applications. objective. This study comprised the initial clinical evaluation (pre-FDA approval) of this device. methods. A total of 54 patients underwent 56 laser procedures: 36 full face and 20 regional procedures. results. Following healing, there was a 91% satisfaction rate. The mean laser-on times were: full face, 27 min; perioral, 7 min; periorbital, 3 min; glabellar, 2.5 min; scar, 5 min; and epidermal lesions, 6 min. conclusions. The NovaScan CO2 laser handpiece is a safe tool for skin resurfacing. In its initial use over a 6-month period there were no device-related complications.
Renormalization group theory for fluid and plasma turbulence

Abstract For the last several decades, renormalization group (RG, or RNG) methods have been applied to a wide variety of problems of turbulence in hydrodynamics and plasma physics. A comprehensive review of this work will be presented, covering RG methods in hydrodynamic turbulence and in turbulent systems with coupled fluctuating fields like magnetohydrodynamic (MHD) turbulence. This review will attempt to specifically consider several questions about RG: (1) Does RG provide an improvement over previous analytical theories like the direct interaction approximation, or is RG a useful simplification of those theories? (2) How are nonlocal, or ‘sweeping’ effects treated in RG formalisms, or are they ignored entirely? (3) Can RG theories treat both local and nonlocal interactions in turbulence?
Negative avalanche feedback detectors for photon-counting optical communications

Negative Avalanche Feedback photon counting detectors with near-infrared spectral sensitivity offer an alternative to conventional Geiger mode avalanche photodiode or phototube detectors for free space communications links at 1 and 1.55 microns. These devices demonstrate linear mode photon counting without requiring any external reset circuitry and may even be operated at room temperature. We have now characterized the detection efficiency, dark count rate, after-pulsing, and single photon jitter for three variants of this new detector class, as well as operated these uniquely simple to use devices in actual photon starved free space optical communications links.
Direct formation of organomanganese bromides using rieke manganese

Abstract The direct formation of organomanganese bromides can be accomplished under mild conditions from the direct oxidative addition of Rieke manganese to alkyl and thienyl bromides.