cssi/SciSciGPT-SciSciNet huggingface dataset:
Parallel processing architectures for rank order and stack filters

Many architectures have been proposed for rank order and stack filtering. To achieve additional speedup in these structures requires the use of parallel processing techniques such as pipelining and block processing. Pipelining is well understood but few block architectures have been developed for rank order and stack filtering. Block processing is essential for additional speedup when the original architecture has reached the throughput limits caused by the underlying technology. A trivial block structure simply repeats a single input, single output structure to generate a multiple input, multiple output structure. Therefore the architecture can achieve speedups equal to the number of multiple outputs or the block size. However, unlike linear filters, the rank order and stack filter outputs are calculated using comparisons. It is possible to share these comparisons within the block structure and thus substantially reduce the size of the block structure. The authors introduce a systematic method for applying block processing to rank order filters and stack filters. This method takes advantage of shared comparisons within the block structure to generate a block filter with shared substructures whose complexity is reduced by up to one-third compared to the original filter structure times the block size. Furthermore, block processing is important for the generation of low power designs. A block structure can trade its increased speedup for a throughput equal to the original single output architecture but with a significantly lower power requirement. The power reduction in the trivial block structures is limited by the power supply voltage. They demonstrate how block structures with shared substructures allow them to continue decreasing the power consumption beyond the limit imposed by the supply voltage. >
aDORe: A Modular, Standards-Based Digital Object Repository

This paper describes the aDORe repository architecture designed and implemented for ingesting, storing, and accessing a vast collection of Digital Objects at the Research Library of the Los Alamos National Laboratory. The aDORe architecture is highly modular and standards-based. In the architecture, the MPEG-21 Digital Item Declaration Language is used as the XML-based format to represent Digital Objects that can consist of multiple datastreams as Open Archival Information System Archival Information Packages (OAIS AIPs). Through an ingestion process, these OAIS AIPs are stored in a multitude of autonomous repositories. A Repository Index keeps track of the creation and location of all the autonomous repositories, whereas an Identifier Locator reflects in which autonomous repository a given Digital Object or OAIS AIP resides. A front-end to the complete environment---the OAI-PMH Federator---is introduced for requesting OAIS Dissmination Information Packages (OAIS DIPs). These OAIS DIPs can be the stored OAIS AIPs themselves, or transformations thereof. This front-end allows OAI-PMH harvesters to recurrently and selectively collect batches of OAIS DIPs from aDORe, and hence to create multiple, parallel services using the collected objects. Another front-end---the OpenURL Resolver---is introduced for requesting OAIS Result Sets. An OAIS Result Set is a dissemination of an individual Digital Object or of its constituent datastreams. Both front-ends make use of an MPEG-21 Digital Item Processing engine to apply those services to OAIS AIPs, Digital Objects, or constituent datastreams that were specified in a dissemination request.
Cheap Talk Reconsidered: New Evidence from CVM

Abstract Two recent studies have shown that “cheap talk” is an effective means of eliminating positive hypothetical bias in experimental and field-auction settings. We further investigate the ability of cheap talk to mitigate positive hypothetical bias in a contingent-valuation phone survey administered to over 4000 households. Positive hypothetical bias is detected in our data by contrasting revealed and stated preference information. However, a short, neutral cheap-talk script appears to exacerbate rather than mitigate the bias. Based on this and mixed evidence from earlier studies, we suggest caution in using cheap talk as an ex ante control for hypothetical bias.
Neveu-Schwarz five-branes and Matrix string theory on K3

Abstract The Matrix theory description of Type IIA string theory on a compact K3 surface as the theory of Neveu-Schwarz five-branes on K3 ×S 1 is analyzed. The full multiplet of space-time BPS states is identified in the five-brane world-volume as fluxes.
Generic Spectrum and Ionization Efficiency of a Heavy Initial Mass Function for the First Stars

We calculate the generic spectral signature of an early population of massive stars at high redshifts. For metal-free stars with mass above 300 M☉, we find that the combined spectral luminosity per unit stellar mass is almost independent of the mass distribution of these stars. To zeroth order, the generic spectrum resembles a blackbody with an effective temperature of ~105 K, making these stars highly efficient at ionizing hydrogen and helium. The production rate of ionizing radiation per stellar mass by stars more massive than ~300 M☉ is larger by ~1 order of magnitude for hydrogen and He I and by ~2 orders of magnitude for He II than the emission from a standard initial mass function. This would result in unusually strong hydrogen and helium recombination lines from the surrounding interstellar medium. It could also alleviate the current difficulty of ionizing the intergalactic medium at z 6 with the cosmic star formation rate inferred at somewhat lower redshifts.
Sn 1984a and delayed detonation models of type ia supernovae

SN 1984A shows unusually large expansion velocities in lines from freshly synthesized material, relative to typical Type Ia supernovae (SNe Ia). SN 1984A is an example of a group of SNe Ia which have very large blueshifts of the P Cygni features but otherwise normal spectra. We have modeled several early spectra of SN 1984A with the multipurpose non-LTE (NLTE) model atmosphere and spectrum synthesis code PHOENIX. We have used as input two delayed-detonation models: CS15DD3 (Iwamoto et al.) and DD21c (Hoflich, Wheeler, & Thielemann). These models show line-expansion velocities which are larger than that for a typical deflagration model like W7, which we have previously shown to fit the spectra of normal SNe Ia quite well. We find these delayed-detonation models to be reasonable approximations to large absorption feature blueshift SNe Ia, like SN 1984A. Higher densities of newly synthesized intermediate-mass elements at higher velocities, v > 15,000 km s-1, are found in delayed-detonation models than in deflagration models. We find that this increase in density at high velocities is responsible for the larger blueshifts in the synthetic spectra. We show that the variations in line width in observed SNe Ia are likely due to density variations in the outer, high-velocity layers of their atmospheres.
Structure of the Conical Flowfield about External Axial Corners

A theoretical and experimental investigation of the flowfield about symmetrical and asymmetrical external axial corners formed by the juncture of swept compressive wedges is presented. A study is made of the nature of inviscid conical cross-flow stagnation points, and the dependence of the streamline pattern on certain flow parameters is derived. The importance of imposing the physically relevant boundary condition for numerical simulations is discussed. For the asymmetrical wedge configuration, the proper boundary condition along the axial corner is shown to be a conical analog of Prandtl-Meyer flow. For the symmetrical configuration, a local solution of the irrotational equations is obtained. The solution is shown to be applicable to cones and internal and external corners. For symmetrical internal corners, the solution is unique; the corner is a nodal point of streamlines. The possible multiple solutions for external corners and cones are discussed. Further insight into the flow structure is revealed by the experimental results. The consistency of the derived flow models with the Euler limit of the Navier-Stokes equations is substantiated by the experimental data.
A Review of “Bath Salts”: Evolving Designer Drugs of Abuse

The abuse of “bath salts” is a fairly new trend amongst teenagers and young adults. These substances, which are sold under various brand names, contain any one, or mixtures of, several synthetic cathinones such as 3,4-methylenedioxypyrovalerone (MDPV). The users of these substances may present with delusions, hallucinations, severe psychomotor agitation, and various other physiological effects. Special screens are required to detect these substances in users. Management is mostly supportive and has involved the use of benzodiazepines, antipsychotics, and general anesthesia in extreme cases. The use of beta blockers in users with elevated blood pressure is contraindicated as it may cause dangerous paradoxical increase in blood pressure.
Magnetar Spin-Down

We examine the effects of a relativistic wind on the spin-down of a neutron star and apply our results to the study of soft gamma repeaters (SGRs), which are thought to be neutron stars with magnetic fields greater than 1014 G. We derive a spin-down formula that includes torques from both dipole radiation and episodic or continuous particle winds. We find that if SGR 1806-20 puts out a continuous particle wind of 1037 ergs s-1, then the pulsar age is consistent with that of the supernova remnant, but the derived surface dipole magnetic field is only 3x1013 G, in the range of normal radio pulsars. If instead the particle wind flows are episodic with small duty cycle, then the observed period derivatives imply magnetar-strength fields, while still allowing characteristic ages within a factor of 2 of the estimated supernova remnant age. Close monitoring of the periods of SGRs will allow us to establish or place limits on the wind duty cycle and thus the magnetic field and age of the neutron star.
Luttinger stripes in antiferromagnets

We propose a model for the physics of stripes in antiferromagnets in which the stripes are described by Luttinger liquids hybridized with antiferromagnetic domains. Using bosonization techniques we study the model in the limit where the magnetic correlation length is larger than the inter-stripe distance and propose an explanation for the commensurate-incommensurate phase transition seen in neutron scattering in the underdoped regime of La2-χx Srχx Cu O4. The explanation is based on a phase to anti-phase domain transition in the spin configuration which is associated with the transverse motion of the stripes. Using a non-linear σ model to describe the antiferromagnetic regions we conjecture the crystalization of the stripes in the magnetically ordered phase.
Configurationally stable, enantioenriched organometallic nucleophiles in stereospecific Pd-catalyzed cross-coupling reactions: an alternative approach to asymmetric synthesis

Several research groups have recently developed methods to employ configurationally stable, enantioenriched organometallic nucleophiles in stereospecific Pd-catalyzed cross-coupling reactions. By establishing the absolute configuration of a chiral alkyltin or alkylboron nucleophile prior to its use in cross-coupling reactions, new stereogenic centers may be rapidly and reliably generated with preservation of the known initial stereochemistry. While this area of research is still in its infancy, such stereospecific cross-coupling reactions may emerge as simple, general methods to access diverse, optically active products from common enantioenriched organometallic building blocks. This minireview highlights recent progress towards the development of general, stereospecific Pd-catalyzed cross-coupling reactions using configurationally stable organometallic nucleophiles.
Bioethics, Vulnerability, and Protection

What makes individuals, groups, or even entire countries vulnerable? And why is vulnerability a concern in bioethics? A simple answer to both questions is that vulnerable individuals and groups are subject to exploitation, and exploitation is morally wrong. This analysis is limited to two areas. First is the context of multinational research, in which vulnerable people can be exploited even if they are not harmed, and harmed even if they are not exploited. The type of multinational research likely to raise the most ethical concerns is that in which the investigators or sponsors are from a powerful industrialised country or a giant pharmaceutical company and the research is conducted in a developing country. Second is the situation of women, who are made vulnerable in cultural settings or in entire countries in which they are oppressed and powerless. In the face of cultural values and practices, or governmental policies, these women suffer serious consequences for their health and even lives. Examples are provided, and it is suggested that in some cases vulnerable individuals can be harmed but not exploited. On the positive side, recent developments reveal a new awareness of exploitation and efforts to enhance the ability of developing countries to protect themselves and their citizens from exploitation at the hands of powerful sponsors of research. In addition, human rights principles are increasingly being used to monitor the actions (or inaction) of governments regarding women's reproductive rights and vulnerability with respect to HIV/AIDS, and to take remedial actions.
Detector discovery in the wild: Joint multiple instance and representation learning

We develop methods for detector learning which exploit joint training over both weak (image-level) and strong (bounding box) labels and which transfer learned perceptual representations from strongly-labeled auxiliary tasks. Previous methods for weak-label learning often learn detector models independently using latent variable optimization, but fail to share deep representation knowledge across classes and usually require strong initialization. Other previous methods transfer deep representations from domains with strong labels to those with only weak labels, but do not optimize over individual latent boxes, and thus may miss specific salient structures for a particular category. We propose a model that subsumes these previous approaches, and simultaneously trains a representation and detectors for categories with either weak or strong labels present. We provide a novel formulation of a joint multiple instance learning method that includes examples from classification-style data when available, and also performs domain transfer learning to improve the underlying detector representation. Our model outperforms known methods on ImageNet-200 detection with weak labels.
Dynamic Analysis of a Deployable Space Structure

A mathematical model and a corresponding simulation code have been developed for investigating the freevibration and forced-response behavior of a deployable space structure. Specifically, the structure considered was the NASA Solar Array Flight Experiment configuration (that has undergone testing on a recent Shuttle flight) where the mast was modeled as an Euler beam column and the solar array was modeled as a membrane. The resulting partial differential equations of motion were transformed such that the boundary conditions were time-invariant. Subsequent use of the Galerkin method resulted in an infinite set of second-order differential equations that were truncated and solved for the frequency and forced-response behavior of the coupled structural components. It is demonstrated that accurate results for frequency and mode-shape characteristics can be obtained with only a small number of generalized coordinates and, thus, appears to be a more computationally efficient algorithm than the finite element method for this type of structure. Similarly, the truncated set of equations was numerically integrated to obtain response histories of certain pertinent variables from a packaged structure, through full deployment, to complete retraction.
Supersymmetry: from the Fermi scale to the Planck scale

The physics of supersymmetry is reviewed from the perspective of physics at ever increasing energies. Starting from the minimal supersymmetric extension of the standard model at the electroweak scale, we proceed to higher energies seeking to understand the origin of the many model parameters. Supersymmetric grand unification, supergravity, and superstrings are introduced sequentially, and their contribution to the sought explanations is discussed. Typical low-energy supersymmetric models are also presented, along with their possible experimental consequences via direct and indirect processes at high-energy physics experimental facilities.
Optimal Allocation of Gold Standard Testing under Constrained Availability: Application to Assessment of HIV Treatment Failure.

The World Health Organization (WHO) guidelines for monitoring the effectiveness of human immunodeficiency virus (HIV) treatment in resource-limited settings are mostly based on clinical and immunological markers (e.g., CD4 cell counts). Recent research indicates that the guidelines are inadequate and can result in high error rates. Viral load (VL) is considered the “gold standard,” yet its widespread use is limited by cost and infrastructure. In this article, we propose a diagnostic algorithm that uses information from routinely collected clinical and immunological markers to guide a selective use of VL testing for diagnosing HIV treatment failure, under the assumption that VL testing is available only at a certain portion of patient visits. Our algorithm identifies the patient subpopulation, such that the use of limited VL testing on them minimizes a predefined risk (e.g., misdiagnosis error rate). Diagnostic properties of our proposed algorithm are assessed by simulations. For illustration, data from th...
Preparations and characterizations of μ3-oxo-hexakis(μ2-carboxylatopyridine-O,O)triaquatrichromium(III) perchlorates

Abstract The preparations of 2- and 4-carboxylatopyridine (HPyCO2) complexes of the type [Cr3O(HPyCO2)6(H2O)3] (ClO4)7·XNaClO4·YHPyCO2·ZH2O are reported. A single-crystal X-ray structural characterization of the 2-HPyCO2 species (X=1, Y=0, Z=6) is described. [Cr3O(C6H5NO2)6(H2O)3](ClO4)7·NaClO4·6H2O, M=1885.35, P63/m, a=13.978(1), c=24.506(3) A, V=4146.3(11) A3, Z=2, D=1.510 g/cm3, λ (Mo Kα)=0.71073 A, F(000)=1902, T=0298 K, final R=0.034 for 1024 reflections with I> 2σ(I). The complex lies on a 6 symmetry operator. The three Oh chromium atoms share a common vertex O(3) at 1.918(2) A; two picolinic acid zwitterions bridge each pair of Cr(III) ions through the carboxylate oxygen atoms, CrObr=1.961(7) A; and terminal water molecules round out the Oh geometry, CrOt=2.058(10) A. Vis-UV-IR absorption spectra for the 2-, 3-, and 4-HPyCO2 complexes are reported. These data are discussed in terms of the corresponding properties of ‘basic chromic acetate’ and related species.
Surface Temperatures in Sliding Systems—A Finite Element Analysis

Finite element equations are developed for studying surface temperatures resulting from frictional heating in sliding systems. The equations include the effect of velocity of moving components, an effect which is found to be quite significant, even at low sliding velocities. A program was written using the equations and it was applied to the study of surface temperatures in two different sliding systems: dry or boundary lubricated sleeve bearings and a labyrinth gas path seal configuration. Very good agreement was achieved between analytical predictions using the program and experimental temperature measurements. The program was used to study the influence of various material parameters on surface temperatures in the two sliding systems.
Maitotoxin: An Inspiration for Synthesis

Maitotoxin holds a special place in the annals of natural products chemistry as the largest and most toxic secondary metabolite known to date. Its fascinating, ladder-like, polyether molecular structure and diverse spectrum of biological activities elicited keen interest from chemists and biologists who recognized its uniqueness and potential as a probe and inspiration for research in chemistry and biology. Synthetic studies in the area benefited from methodologies and strategies that were developed as part of chemical synthesis programs directed toward the total synthesis of some of the less complex members of the polyether marine biotoxin class, of which maitotoxin is the flagship. This account focuses on progress made in the authors’ laboratories in the synthesis of large maitotoxin domains with emphasis on methodology development, strategy design, and structural comparisons of the synthesized molecules with the corresponding regions of the natural product. The article concludes with an overview of maitotoxin’s biological profile and future perspectives.
Intrinsic random functions and universal kriging on the circle

Abstract Intrinsic random functions (IRF) provide a versatile approach when the assumption of second-order stationarity is not met. Here, we develop the IRF theory on the circle with its universal kriging application. Unlike IRF in Euclidean spaces, where differential operations are used to achieve stationarity, our result shows that low-frequency truncation of the Fourier series representation of the IRF is required for such processes on the circle. All of these features and developments are presented through the theory of reproducing kernel Hilbert space. In addition, the connection between kriging and splines is also established, demonstrating their equivalence on the circle.
Stability of a one-dimensional discrete-time asynchronous swarm

In this correspondence, we consider a discrete time one-dimensional asynchronous swarm. First, we describe the mathematical model for motions of the swarm members. Then, we analyze the stability properties of that model. The stability concept that we consider, which matches exactly with stability of equilibria in control theory, characterizes stability of a particular position (relative arrangement) of the swarm members. We call that position the comfortable position (with comfortable intermember distances). Our swarm model and stability analysis are different from other asynchronous swarm models considered in the literature. In particular, in our analysis we employ results on contractive mappings from the parallel and distributed computation literature. The application of these results to the swarm coordination problem is important by itself since they might prove useful also in n-dimensional swarms.
THE PRECISION AND ACCURACY OF EARLY EPOCH OF REIONIZATION FOREGROUND MODELS: COMPARING MWA AND PAPER 32-ANTENNA SOURCE CATALOGS

As observations of the Epoch of Reionization (EoR) in redshifted 21 cm emission begin, we assess the accuracy of the early catalog results from the Precision Array for Probing the Epoch of Reionization (PAPER) and the Murchison Wide-field Array (MWA). The MWA EoR approach derives much of its sensitivity from subtracting foregrounds to <1% precision, while the PAPER approach relies on the stability and symmetry of the primary beam. Both require an accurate flux calibration to set the amplitude of the measured power spectrum. The two instruments are very similar in resolution, sensitivity, sky coverage, and spectral range and have produced catalogs from nearly contemporaneous data. We use a Bayesian Markov Chain Monte Carlo fitting method to estimate that the two instruments are on the same flux scale to within 20% and find that the images are mostly in good agreement. We then investigate the source of the errors by comparing two overlapping MWA facets where we find that the differences are primarily related to an inaccurate model of the primary beam but also correlated errors in bright sources due to CLEAN. We conclude with suggestions for mitigating and better characterizing these effects.
The Thurston polytope for four-stranded pretzel links

The Thurston norm is a fundamental measure of the complexity of second homology classes in a three-manifold. When the manifold is a knot complement, the second homology is spanned by any Seifert surface for the knot K , and the genus of K is defined to be the least genus of any Seifert surface for K . In the case of a link in the three-sphere, the analogous objects are surfaces whose boundaries lie on the components of the link. In this paper we study the two-component pretzel links P. 2r1 1;2q1; 2q2;2r2C1/;ri;qi2 Z C , which we denote by Pq1;r1;q2;r2 , and we determine the dual Thurston polytopes of their complements. Let B T .Pq1;r1;q2;r2 / be the unit ball with respect to the dual Thurston norm on H1.S 3 Pq1;r1;q2;r2 IR/. We specify as a basis for H1.S 3 Pq1;r1;q2;r2 IR/ the set of oriented meridians of the link components. Identify the meridians with the coordinate vectors of R 2 so that the meridian of the unknotted component U is the vector .1;0/, and the meridian of the knotted component K is the vector .0;1/. Let rBD max.r1;r2/, rS D min.r1;r2/, qB D max.q1;q2/, and qS D min.q1;q2/. In the special case q1D q2D q and r1D r2D r , we denote Pq1;r1;q2;r2 by Pq;r .
Separation of Circulating Tokens

Self-stabilizing distributed control is often modeled by token abstractions. For a cyber-physical system, tokens may represent physical objects whose movement is controlled. The problem studied in this paper is to ensure that a synchronous system with m circulating tokens has at least d distance between tokens. This problem is first considered in a ring where d is given whilst m and the ring size n are unknown. The protocol solving this problem can be uniform, with all processes running the same program, or it can be non-uniform, with some processes acting only as token relays. The protocol for this first problem is simple, and can be expressed with Petri net formalism. A second problem is to maximize d when m is given, and n is unknown. For the second problem, the paper presents a non-uniform protocol with a single corrective process.
Dynamic Snap-Through of Thin-Walled Structures by a Reduced-Order Method

The goal of this investigation is to further develop nonlinear modal numerical simulation methods for application to geometrically nonlinear response of structures exposed to combined high intensity random pressure fluctuations and thermal loadings. The study is conducted on a flat aluminum beam, which permits a comparison of results obtained by a reduced-order analysis with those obtained from a numerically intensive simulation in physical degrees-of-freedom. A uniformly distributed thermal loading is first applied to investigate the dynamic instability associated with thermal buckling. A uniformly distributed random loading is added to investigate the combined thermal-acoustic response. In the latter case, three types of response characteristics are considered, namely: (i) small amplitude vibration around one of the two stable buckling equilibrium positions, (ii) intermittent snap-through response between the two equilibrium positions, and (iii) persistent snap-through response between the two equilibrium positions. For the reduced order analysis, four categories of modal basis functions are identified including those having symmetric transverse (ST), anti-symmetric transverse (AT), symmetric in-plane (SI), and anti-symmetric in-plane (AI) displacements. The effect of basis selection on the quality of results is investigated for the dynamic thermal buckling and combined thermal-acoustic response. It is found that despite symmetric geometry, loading, and boundary conditions, the AT and SI modes must be included in the basis as they participate in the snap-through behavior.
Effect of Client Reputation on Audit Fees at the Office Level: An Examination of S&P 500 Index Membership

SUMMARY: Prior studies have examined the effect of a decline in the auditor's or client's reputation on auditor switching, market shares, and stock prices. We extend these studies by examining the effect of an unexpected increase in a client's reputation on audit fees at the office level. We argue that association with a reputed client will enhance the auditor's reputation and establish a brand name, thus enabling the auditor to charge higher fees from other clients. Using a client's inclusion into the prestigious S&P 500 index as a proxy for the client's change in reputation, we find that the audit fees are discounted for this S&P client when it enters the index. The audit fee for this client increases following its exit from the index. We posit that changes in the audit fees for the S&P 500 clients are attributable to the changes in the reporting quality of these firms following their entry to and exit from the index. We also find increases in the audit fees of non-S&P clients of the audit office aroun...
THE COSMIC MICROWAVE BACKGROUND AND PARTICLE PHYSICS

▪ Abstract In forthcoming years, connections between cosmology and particle physics will become increasingly important with the advent of a new generation of cosmic microwave background (CMB) experiments. Here, we review a number of these links. Our primary focus is on new CMB tests of inflation. We explain how the inflationary predictions for the geometry of the Universe and primordial density perturbations will be tested by CMB temperature fluctuations, and how the gravitational waves predicted by inflation can be pursued with the CMB polarization. The CMB signatures of topological defects and primordial magnetic fields from cosmological phase transitions are also discussed. Furthermore, we review current and future CMB constraints on various types of dark matter (e.g. massive neutrinos, weakly interacting massive particles, axions, vacuum energy), decaying particles, the baryon asymmetry of the Universe, ultra-high-energy cosmic rays, exotic cosmological topologies, and other new physics.
Combustion Performance of Biodiesel and Diesel-Vegetable Oil Blends in a Simulated Gas Turbine Burner

Recent increases in fuel costs, concerns for global warming, and limited supplies of fossil fuels have prompted wide spread research on renewable liquid biofuels produced domestically from agricultural feedstock. In this study, two types of biodiesels and vegetable oil (VO) are investigated as potential fuels for gas turbines to generate power. Biodiesels produced from VO and animal fat were considered in this study. The problems of high viscosity and poor volatility of VO (soybean oil) were addressed by using diesel-VO blends with up to 30% VO by volume. Gas chromatography/mass spectrometry, thermogravimetric analysis, and density, kinematic viscosity, surface tension, and water content measurements were used to characterize the fuel properties. The combustion performance of different fuels was compared experimentally in an atmospheric pressure burner with an air-assist injector and swirling primary air around it. For different fuels, the effect of the atomizing airflow rate on Sauter mean diameter was determined from a correlation for air-assist atomizers. Profiles of nitric oxides (NO x ) and carbon monoxide (CO) emissions were obtained for different atomizing airflow rates, while the total airflow rate was kept constant. The results show that despite the compositional differences, the physical properties and emissions of the two biodiesel fuels are similar. Diesel-VO fuel blends resulted in slightly higher CO emissions compared with diesel, while the NO x emissions correlated well with the flame temperature. The results show that the CO and NO x emissions are determined mainly by fuel atomization and fuel/air mixing processes, and that the fuel composition effects are of secondary importance for fuels and operating conditions of the present study.
Surface representations of two- and three-dimensional fluid flow topology

We discuss our work using critical point analysis to generate representations of the vector field topology of numerical flow data sets. Critical points are located and characterized in a two-dimensional domain, which may be either a two-dimensional flow field or the tangential velocity field near a three-dimensional body. Tangent curves are then integrated out along the principal directions of certain classes of critical points. The points and curves are linked to form a skeleton representing the two-dimensional vector field topology.When generated from the tangential velocity field near a body in a three-dimensional flow, the skeleton includes the critical points and curves which provide a basis for analyzing the three-dimensional structure of the flow separation. The points along the separation curves in the skeleton are used to start tangent curve integrations to generate surfaces representing the topology of the associated flow separations.
Influence of stapler size used at ileal pouch–anal anastomosis on anastomotic leak, stricture, long-term functional outcomes, and quality of life

Abstract Background The aim of this study was to evaluate whether stapler size used at ileal pouch–anal anastomosis (IPAA) influences outcomes. Methods Data of patients undergoing stapled IPAA (1983–2007) were obtained. Differences between groups A (stapler size 28–29 mm) and B (31–33 mm) for pre- and perioperative factors, stricture, leak, quality of life (QOL), and function were compared. Associations between stapler size and stricture or leak were assessed with a multivariable Cox model. Results Groups A (n = 1,221) and B (n = 899) had comparable age, diagnosis, body mass index (BMI), and albumin level. Group B had more males ( P P P = .08) or stricture (1.9% vs 2.7%, P = .1) for groups A and B. On multivariate analysis, female gender was associated with stricture, while greater BMI and male gender were associated with leak. Group A had greater urgency at 1 year and nighttime pad use at 15 years. The other determinants of function and QOL were similar. Conclusions There was no significant association between the size of stapler used at IPAA and long-term complications.
Critical path analysis of TCP transactions

Improving the performance of data transfers in the Internet (such as Web transfers) requires a detailed understanding of when and how delays are introduced. Unfortunately, the complexity of data transfers like those using HTTP is great enough that identifying the precise causes of delays is difficult. In this paper, we describe a method for pinpointing where delays are introduced into applications like HTTP by using critical path analysis. By constructing and profiling the critical path, it is possible to determine what fraction of total transfer latency is due to packet propagation, network variation (e.g., queueing at routers or route fluctuation), packet losses, and delays at the server and at the client. We have implemented our technique in a tool called tcpeval that automates critical path analysis for Web transactions. We show that our analysis method is robust enough to analyze traces taken for two different TCP implementations (Linux and FreeBSD). To demonstrate the utility of our approach, we present the results of critical path analysis for a set of Web transactions taken over 14 days under a variety of server and network conditions. The results show that critical path analysis can shed considerable light on the causes of delays in Web transfers, and can expose subtleties in the behavior of the entire end-to-end system.
Two simple approximations to the distributions of quadratic forms

Man yt est statistics are asymptotically equivalent to quadratic forms of normal variables, which are further equivalent to T ¼ P d ¼ 1 l i z 2 with z i being independent and following N ð 0 ; 1 Þ .T wo approximations to the distribution of T have been implemented in popular software and are widely used in evaluating various models. It is important to know how accurate these approximations ar ew hen compare dt oe ach other and to the exact distribution of T .T he paper systematically studies the quality of the two approximations and examines the effect of the l i and the degree so ff reedom d by analysis and Monte Carlo .T he results imply that the adjusted distribution for T can be as good as knowing its exact distribution. When the coefficient of variation of the l i is small, the rescaled statistic T R ¼ dT= ð P d i ¼ 1 l i Þ is also adequate for practical model inference. But comparing T R against x 2 will inflate type Ie rrors when substantial differences exist among the l i ,e specially ,w hen d is also large.
Financial development and the end-use of migrants' remittances

This study examines how the level of financial development in a community affects households’ decisions over how remittance income is spent. My findings suggest that in communities without banks remittances are more likely to be used for productive investments or to purchase assets. Increasing the size of the financial sector in communities with banks present increases the likelihood that remittances are used for productive investment and decreases the likelihood that remittances are used for general consumption. Finally, I find that the services offered by banks also affect the likelihood of using remittances for productive investment, purchasing assets, and general consumption. F24; G21; D19.
Optimal auctions via the multiplicative weight method

We show that the multiplicative weight update method provides a simple recipe for designing and analyzing optimal Bayesian Incentive Compatible (BIC) auctions, and reduces the time complexity of the problem to pseudo-polynomial in parameters that depend on single agent instead of depending on the size of the joint type space. We use this framework to design computationally efficient optimal auctions that satisfy ex-post Individual Rationality in the presence of constraints such as (hard, private) budgets and envy-freeness. We also design optimal auctions when buyers and a seller's utility functions are non-linear. Scenarios with such functions include (a) auctions with "quitting rights", (b) cost to borrow money beyond budget, (c) a seller's and buyers' risk aversion. Finally, we show how our framework also yields optimal auctions for variety of auction settings considered in Alaei et al and Cai et al, albeit with pseudo-polynomial running times.
Seismic velocity structures in the southern California plate-boundary environment from double-difference tomography

SUMMARY We present tomographic images of crustal structures in the southern California plate-boundary area, with a focus on the San Jacinto fault zone (SJFZ), based on double-difference inversions of earthquake arrival times. Absolute arrival times of 247 472 P and 105 448 S wave phase picks for 5493 earthquakes recorded at 139 stations in southern California are used. Starting with a layered 1-D model, and continuing in later iterations with various updated initial models, we invert the data for Vp and Vs in a 270 km long, 105 km wide and 35 km deep volume around the SJFZ using a spatially variable grid with higher density around the SJFZ. The examined volume stretches from Cajon Pass to the northernmost Imperial Fault Zone and includes portions of the southern San Andreas Fault (SAF), the Elsinore Fault and the Brawley Seismic Zone in the Salton Trough. Because differential traveltimes used in the double-difference inversions are most sensitive to near-source structures, we obtain high resolution around the earthquake sources. After 30 iterations we improve the average traveltime misfit by a factor of 16. Though ray coverage is limited at shallow depths, we obtain detailed images of seismic velocities from 3 to 20 km throughout much of the study area. Our final velocity results show zones of low-velocity and anomalous Vp/Vs ratios associated with various fault strands and sedimentary basins, along with clear velocity contrasts across the SJFZ and the southern SAF. The velocity reductions in fault zone regions are generally highest in geometrically complex areas (up to 30–50 per cent in the top few kilometres), are higher for Vs than for Vp, and follow a flower-type pattern with depth. In the central section of the SJFZ, from the San Jacinto valley to the trifurcation area, the northeast side of the fault has generally higher seismic velocities than the southwest block. The obtained contrasts of Vp are more persistent and higher (up to 20 per cent) than the contrasts of Vs (up to 15 per cent), although the differences may stem (at least partially) from the higher resolution of Vp images. In the SJFZ sections to the northwest and southeast, there are patches with reversed velocities contrasts especially in the shallow crust near the San Jacinto Valley and other basins. Along the Banning fault there is no clear velocity contrast. For the southern SAF, the northeast side has generally lower seismic velocities in the seismogenic zone with patches of contrast reversals in the shallow crust. In the Brawley Seismic Zone, the northeast side has somewhat lower velocities in the ∼20 km section near the southern SAF and higher velocities farther to the southwest. The imaged features have important implications for various aspects of earthquake and crustal dynamics in the region.
The Local Interstellar Ultraviolet Radiation Field

I have used the Hipparcos Input Catalogue, together with Kurucz model stellar atmospheres and information on the strength of the interstellar extinction, to create a model of the expected intensity and spectral distribution of the local interstellar ultraviolet radiation field, under various assumptions concerning the albedo a of the interstellar grains. (This ultraviolet radiation field is of particular interest because of the fact that ultraviolet radiation is capable of profoundly affecting the chemistry of the interstellar medium.) By comparing my models with the observations, I am able to conclude that the albedo a of the interstellar grains in the far-ultraviolet is very low, perhaps a = 0.1. I also advance arguments that my present determination of this albedo is much more reliable than any of the many previous (and conflicting) ultraviolet interstellar grain albedo determinations. Beyond this, I show that the ultraviolet background radiation that is observed at high Galactic latitudes must be extragalactic in origin, as it cannot be backscatter of the interstellar radiation field.
Six-year experience: long-term disease control outcomes for partial breast irradiation using MammoSite balloon brachytherapy

BACKGROUND: This report describes estimated 4-year tumor bed and ipsilateral breast recurrence-free intervals, event-free survival, disease-specific survival, and overall survival in a cohort of MammoSite brachytherapy (MBT) patients with mature follow-up treated at a single institution over a 6-year period. METHODS AND MATERIALS: An analysis of MBT cases was performed by using a prospectively collected quality-assurance database, departmental chart review, and electronic medical records. Patient-, tumor-, treatment-, and outcome-specific data were extracted and recorded into a research database. Patients were eligible for inclusion in this analysis if they were at least 6 months post-MBT. RESULTS: From May 2002 through March 2008, 111 MBT patients have been treated and were eligible for the present analysis. With a median follow-up of 46 months, the estimated 4-year outcomes for the entire cohort were tumor bed control 99%, ipsilateral breast control 95%, event-free survival 88%, disease-specific survival 97%, and overall survival 92%. CONCLUSIONS: The present study shows low rates of local and ipsilateral breast disease failure in a well-defined cohort of MBT patients with mature follow-up.
Identification of second trimester screen positive pregnancies at increased risk for congenital heart defects.

Objective To examine whether second trimester biomarkers could be used to identify screen positive pregnancies at increased risk for congenital heart defects (CHDs) and measure the effect of using different biomarker cut points on the detection of CHDs and on the performance of predictive models. Methods Included were 19,402 pregnancies without chromosomal defects, which were screen positive for Down syndrome or other birth defects based on maternal serum measurements of alpha-fetoprotein (AFP), human chorionic gonadotrophin (hCG), and unconjugated estriol (uE3). Logistic regression models were built that compared biomarkers for CHD cases compared to controls. Results CHD cases were more likely to be screen positive for trisomy-18, to have a nuchal fold (NF) ≥ 5 mm, and/or to have an hCG multiple of the median (MoM) ≥ 95th percentile in models that considered screen positive grouping. In models that did not consider screen positive grouping, cases were more likely to have a NF ≥ 5 mm, an AFP MoM ≤10th percentile, an hCG MoM ≤25th percentile, and/or an hCG MoM ≥ 75th percentile. Conclusion Along with NF, second trimester maternal serum biomarkers may be useful indicators for fetal and newborn evaluation for CHDs in screen positive pregnancies without identified chromosomal defects. Copyright © 2009 John Wiley & Sons, Ltd.
Practical load balancing for content requests in peer-to-peer networks

This paper studies the problem of balancing the demand for content in a peer-to-peer network across heterogeneous peer nodes that hold replicas of the content. Previous decentralized load balancing techniques in distributed systems base their decisions on periodic updates containing information about load or available capacity observed at the serving entities. We show that these techniques do not work well in the peer-to-peer context; either they do not address peer node heterogeneity, or they suffer from significant load oscillations which result in unutilized capacity. We propose a new decentralized algorithm, Max-Cap, based on the maximum inherent capacities of the replica nodes. We show that unlike previous algorithms, it is not tied to the timeliness or frequency of updates, and consequently requires significantly less update overhead. Yet, Max-Cap can handle the heterogeneity of a peer-to-peer environment without suffering from load oscillations.
Highly enantioselective and regioselective nickel-catalyzed coupling of allenes, aldehydes, and silanes.

A complex derived from Ni(cod)2 and NHC−IPr catalyzes a three-component coupling reaction involving allenes, aldehydes, and organosilanes and transfers the axial chirality of the allene to a stereogenic center in the product with very high fidelity. An unexpected regioselectivity is observed; favored are allylic rather than homoallylic alcohol derivatives, corresponding to the unusual process of coupling two electrophilic atoms: the allene sp and aldehyde carbon atoms. In all cases, high enantioselectivity, high Z/E selectivity, and, with differentially substituted allenes, high site selectivity are observed. This transformation represents the first enantioselective multicomponent coupling process of allenes.
Rhodium(II)-Catalyzed Nondirected Oxidative Alkenylation of Arenes: Arene Loading at One Equivalent†

A bimetallic Rh(II) catalyst promoted the C-H alkenylation of simple arenes at 1.0 equivalent without the use of a directing group. A phosphine ligand as well as cooperative reoxidation of Rh(II) with Cu(TFA)2 and V2O5 proved essential in providing monoalkenylated products in good yields and selectivities, especially with di- and trisubstituted arenes.