cssi/SciSciGPT-SciSciNet huggingface dataset:
Source Regions of the Slow Solar Wind

While the fast solar wind is generally thought to originate from coronal holes, the source of the slow solar wind is only known to be associated with the highly structured and highly variable streamer belt. There is growing evidence from multiple-station intensity scintillation measurements of solar wind velocity—often referred to as IPS for interplanetary scintillation—that the slow wind originates in localized regions of the solar corona overlying the streamer belt. In this paper, velocity structure in the corona is investigated based on estimates obtained from the power spectra of single-station intensity scintillation measurements. These measurements were conducted with the S- and X-band (13 and 3.6 cm wavelengths, respectively) radio signals of Voyager 2 during its superior conjunctions in 1979 and 1982. Unlike previous studies, simultaneous estimates of density fluctuation from the same intensity scintillation measurements were available to provide the coronal context for the velocity measurements. Solar eclipse pictures show that with increasing heliocentric distance, coronal streamers taper to narrow extensions or stalks of angular size 1–2° by a few solar radii. Prominent enhancements in density fluctuation characterizing such streamer stalks are found to coincide with the low speed wind measured by Voyager 2, leading to the first observational evidence for streamer stalks as the long sought coronal sources of the slow solar wind.
Merging photoredox with nickel catalysis: Coupling of α-carboxyl sp3-carbons with aryl halides

Over the past 40 years, transition metal catalysis has enabled bond formation between aryl and olefinic (sp(2)) carbons in a selective and predictable manner with high functional group tolerance. Couplings involving alkyl (sp(3)) carbons have proven more challenging. Here, we demonstrate that the synergistic combination of photoredox catalysis and nickel catalysis provides an alternative cross-coupling paradigm, in which simple and readily available organic molecules can be systematically used as coupling partners. By using this photoredox-metal catalysis approach, we have achieved a direct decarboxylative sp(3)-sp(2) cross-coupling of amino acids, as well as α-O- or phenyl-substituted carboxylic acids, with aryl halides. Moreover, this mode of catalysis can be applied to direct cross-coupling of C(sp³)-H in dimethylaniline with aryl halides via C-H functionalization.
Hydrodynamic simulations of bubble collapse and picosecond sonoluminescence

Numerical hydrodynamic simulations of the growth and collapse of a 10 μm air bubble in water were performed. Both the air and the water are treated as compressible fluids. The calculations show that the collapse is nearly isentropic until the final 10 ns, after which a strong spherically converging shock wave evolves and creates enormous temperatures and pressures in the inner 0.02 μm of the bubble. The reflection of the shock from the center of the bubble produces a diverging shock wave that quenches the high temperatures (≳30 eV) and pressures in less than 10 ps (full width at half maximum). The picosecond pulse widths are due primarily to spherical convergence/divergence and nonlinear stiffening of the air equation of state that occurs at high pressures. The results are consistent with recent measurements of sonoluminescence that had optical pulse widths less than 50 ps and 30 mW peak radiated power in the visible.
Nonlinear Model Tracking by Robot Manipulators

The modified model reference adaptive control (MRAC) technique is used to make a highly nonlinear and coupled n DOF robot manipulator with uncertain parameters to follow a prescribed model in a real time and on bounded work-space. The time and accuracy of the tracking may be stipulated. The corresponding adaptive laws are given in terms of exactly integrable simple linear equations and the signal adaptive feedback controller is specified in a closed form, thus making the onboard computer to work as a calculator. An RP-manipulator example illustrates the results.
Monte Carlo exploration of warped higgsless models

We have performed a detailed Monte Carlo exploration of the parameter space for a warped Higgsless model of electroweak symmetry breaking in 5 dimensions. This model is based on the SU(2)L × SU(2)R × U(1)B−L gauge group in an AdS5 bulk with arbitrary gauge kinetic terms on both the Planck and TeV branes. Constraints arising from precision electroweak measurements and collider data are found to be relatively easy to satisfy. We show, however, that the additional requirement of perturbative unitarity up to the cut-off, 10 TeV, in WL+WL− elastic scattering in the absence of dangerous tachyons eliminates all models. If successful models of this class exist, they must be highly fine-tuned.
On the Origin of the Global Schmidt Law of Star Formation

One of the most puzzling properties of observed galaxies is the universality of the empirical correlation between the star formation rate and the average gas surface density on kiloparsec scales (the Schmidt law). In this study, I present results of self-consistent cosmological simulations of high-redshift galaxy formation that reproduce the Schmidt law naturally, without assuming it, and provide some clues to this puzzle. The simulations have a dynamic range high enough to identify individual star-forming regions. The results indicate that the global Schmidt law is a manifestation of the overall density distribution of the interstellar medium. In particular, the density probability distribution function (PDF) in the simulated disks has a well-defined generic shape that can be approximated by a lognormal distribution at high densities. The PDF in a given region of the disk depends on the local average surface density Σg. The dependence is such that the fraction of gas mass in the high-density tail of the distribution scales as Σ with n ≈ 1.4, which gives rise to the Schmidt-like correlation. The high-density tail of the PDF is remarkably insensitive to the inclusion of feedback and details of the cooling and heating processes. This indicates that the global star formation rate is determined by the supersonic turbulence driven by gravitational instabilities on large scales, rather than stellar feedback or thermal instabilities on small scales.
The fascinating noncentrosymmetric copper(II) phosphates synthesized via CsCl salt-inclusion.

Two new noncentrosymmetric (NCS) solids were isolated via high-temperature, salt-inclusion reactions, Cs2Cu7(P2O7)4·6CsCl (1, CU-9) and Cs2Cu5(P2O7)3·3CsCl (2, CU-11). These copper(II) phosphates exhibit novel open-framework structures conceptually templated by extended Cs−Cl salt. The latter resides cooperatively in the channels upon the formation of the NCS Cu−P−O frameworks, leading to the formation of fascinating salt lattices centered by the NaCl-type core. These new discoveries are significant for they may give rise to a new route for the templated synthesis of NCS solids. We are to show here the structural correlation of the newly discovered hybrid solids, and the role of the chlorine atoms in the “intergrowth” of covalent/ionic sublattices.
Spherically-Actuated Platform Manipulator

This article presents the inverse and forward pose and rate kinematics solutions for a novel 6-DOF platform manipulator, actuated by two base-mounted spherical actuators. The moving platform is connected to the fixed base by two identical spherical-prismatic-universal serial chain legs. The S-joint is active, and the remaining two joints in each chain are passive. An analytical solution is presented for the inverse pose problems, a semi-analytical solution is presented for the rate problems, and the numerical Newton–Raphson technique is employed to solve the forward pose problem. Unfortunately, the passive joint variables cannot be ignored in the kinematics solutions as they can for the Gough–Stewart platform. Examples are presented and hardware has been built, using two Rosheim Omni-Wrists on loan from NASA as the spherical actuators. © 2001 John Wiley & Sons, Inc.
Strategies to Increase Student Interest in Aging

SUMMARY. Due to changing demographics, all social workers will have experience working with older clients and their families within professional roles. Unfortunately, social work education continues to lag in preparing students to be effective in practice with aging clients. Several strategies are presented with the goal of increasing student interest in the field of aging. At the program level, initiatives include using experiential learning, infusing aging content into required courses, and enhancing faculty capacity in aging. In addition, social work programs can build collaborations within the university setting and practice community. Overall, the goal is to present aging as an exciting and rewarding field of practice, and ensure that all students have the knowledge and skills to be effective in practice with older clients. [Article copies available for a fee from The Haworth Document Delivery Service: 1-800-HAWORTH. E-mail address: Website: © 2002
On the Dramatic Spin-up/Spin-Down Torque Reversals in Accreting Pulsars

Dramatic torque reversals between spin-up and spin-down have been observed in half of the persistent X-ray pulsars monitored by the BATSE all-sky monitor on the Compton Gamma Ray Observatory. Theoretical models developed to explain early pulsar timing data can explain spin-down torques via a disk-magnetosphere interaction if the star nearly corotates with the inner accretion disk. To produce the observed BATSE torque reversals, however, these equilibrium models require the disk to alternate between two mass accretion rates, with ˙M5 producing accretion torques of similar magnitude but always of opposite sign. Moreover, in at least one pulsar (GX 114) undergoing secular spin-down, the neutron star spins down faster during brief (~20 day) hard X-ray flares—this is opposite the correlation expected from standard theory, assuming that BATSE pulsed flux increases with mass accretion rate. The 10 day to 10 yr intervals between torque reversals in these systems are much longer than any characteristic magnetic or viscous timescale near the inner disk boundary and are more suggestive of a global disk phenomenon. We discuss possible explanations of the observed torque behavior. Despite the preferred sense of rotation defined by the binary orbit, the BATSE observations are urprisingly consistent with an earlier suggestion for GX 1+4: the disks in these systems somehow alternate between episodes of prograde and retrograde rotation. We are unaware of any mechanism that could produce a stable retrograde disk in a binary undergoing Roche lobe overflow, but such flip-flop behavior does occur in numerical simulations of wind-fed systems. One possibility is that the disks in some of these binaries are fed by an X-ray–excited wind.
Some remarks on a paper by L. Carlitz

We study a family of orthogonal polynomials which generalizes a sequence of polynomials considered by L. Carlitz. We show that they are a special case of the Sheffer polynomials and point out some interesting connections with certain Sobolev orthogonal polynomials.
NPACI Rocks: tools and techniques for easily deploying manageable Linux clusters

High-performance computing clusters (commodity hardware with low-latency, high-bandwidth interconnects) based on Linux are rapidly becoming the dominant computing platform for a wide range of scientific disciplines. Yet, straightforward software installation, maintenance, and health monitoring for large-scale clusters has been a consistent and nagging problem for non-cluster experts. The NPACI Rocks distribution takes a fresh perspective on management and installation of clusters to dramatically simplify software version tracking and cluster integration. NPACI Rocks incorporates the latest Red Hat distribution (including security patches) with additional cluster-specific software. Using the identical software tools used to create the base distribution, users can customize and localize Rocks for their site. Strong adherence to widely-used (de facto) tools allows Rocks to move with the rapid pace of Linux development. Version 2.2.1 of the toolkit is available for download and installation. Over 100 Rocks clusters have been built by non-cluster experts at multiple institutions (residing in various countries) providing a peak aggregate of 2 TFLOPS of clustered computing. Copyright © 2003 John Wiley & Sons, Ltd.
The origin and health risks of PCDD and PCDF

Abstract PCDD/PCDF are ubiquitous in the emissions of trash-burning incinerators. They are synthesized in the cooler parts of the incinerator, and emissions are not reduced by controlling combustion conditions. Estimates of maximum lifetime risks of PCDD/ PCDF emissions range over two orders of magnitude from a minimum of one per million. This risk is greater than that which has triggered regulatory procedures against airborne carcinogens by U.S. EPA. Computations based on PCDD/PCDF in adipose tissue of a representative sample of the U.S. population indicate a national lifetime cancer risk of 330–1400 per million depending on the choice of equivalence methodology. In comparison, U.S. EPA has regulated environmental exposure to benzene based on a national lifetime cancer risk of 71.4. Because waste-burning incinerators contribute significantly to this risk, it is the authors' opinion that their PCDD/PCDF emissions should be reduced if U.S. EPA is to be consistent in its regulatory practice.
A Survey of Maneuvering Target Tracking—Part VIb: Approximate Nonlinear Density Filtering in Mixed Time

This paper is Part VIb of a comprehensive survey of maneuvering target tracking without addressing the so-called measurement-origin uncertainty. It provides an in-depth coverage of various approximate density-based nonlinear filters in mixed time developed particularly for handling the uncertainties induced by potential target maneuvers as well as nonlinearities in the dynamical systems commonly encountered in target tracking. An emphasis is given to the more recent results, especially those with good potential for tracking applications. Approximate nonlinear filtering techniques for point estimation have been covered in a previous part. Approximate nonlinear filtering in discrete time and sampling-based nonlinear filters will be surveyed in forthcoming parts.
Competition and inter-firm credit: Theory and evidence from firm-level data in Indonesia

Abstract Using firm-level data we investigate the relationship between trade credit and suppliers' market structure and find a ∩-shaped relationship between competition and trade credit, with a discontinuous increase in credit provision between monopoly and duopoly. This “big jump” arises because monopolists are more likely to not offer any trade credit than firms in competitive environments. Our model exploits the fundamentally different nature between cash and trade credit sales, arguing that firms are unable to commit ex ante to a trade credit price. We show that monopolists will often sell only on cash, while credit is always provided in competitive environments.
PROJECT INVESTMENT ANALYSIS AND ANTICIPATED GOVERNMENT MANDATED EXPENDITURES

Dr. Trivoli is Associate Professor of Finance and Director of the Center for Business Services, University of Texas atArlington. This study was supported by a grantfrom the Organized Research Fund administered by the Graduate School, University of Texas at Arlington. Many valuable contributions were made by Paul W. Allen, General Dynamics Corp., and Jack P. Friedman, University of Texas at Arlington.
Optical Properties of Radio-selected Narrow-Line Seyfert 1 Galaxies

We present results from the analysis of the optical spectra of 47 radio-selected narrow-line Seyfert 1 galaxies (NLS1s). These objects are a subset of the First Bright Quasar Survey (FBQS) and were initially detected at 20 cm (flux density limit {approx} 1 mJy) in the VLA FIRST Survey. We run Spearman rank correlation tests on several sets of parameters and conclude that, except for their radio properties, radio-selected NLS1 galaxies do not exhibit significant differences from traditional NLS1 galaxies. Our results are also in agreement with previous studies suggesting that NLS1 galaxies have small black hole masses that are accreting very close to the Eddington rate. We have found 16 new radio-loud NLS1 galaxies, which increases the number of known radio-loud NLS1 galaxies by a factor of {approx} 5.
Detection of the Cosmic Infrared Background at 2.2 and 3.5 Microns Using DIRBE Observations

We compare data from the Diffuse Infrared Background Experiment (DIRBE) on COBE to the model of the infrared sky provided by Wainscoat and colleagues in 1992. The model is first compared with broadband K (2.2 ?m) star counts. Its success at K band lends credence to its physical approach, which is extrapolated to the L band (3.5 ?m). We have analyzed the histograms of the pixel-by-pixel intensities in the 2.2 and 3.5 ?m maps from DIRBE after subtracting the zodiacal light. The shape of these histograms agrees quite well with the histogram shape predicted using the Wainscoat model of the infrared sky, but the predicted histograms must be displaced by a constant intensity in order to match the data. This shift is the cosmic infrared background, which is 16.9 ? 4.4 kJy sr-1 or 23.1 ? 5.9 nW m-2 sr-1 at 2.2 ?m and 14.4 ? 3.7 kJy sr-1 or 12.4 ? 3.2 nW m-2 sr-1 at 3.5 ?m. Combining our near-IR results with the far-IR background detected by Hauser and colleagues in 1998 suggests that roughly half of the radiation produced by galaxies is absorbed by dust and reradiated in the far-IR.
Site-directed oxidative protein crosslinking

Abstract Many important biological processes are catalyzed by large multiprotein complexes. A central goal in the study of these “protein machines” is to characterize the organization of proteins and to determine if this organization changes during the catalytic cycle. For this purpose, methodology has been developed to deliver a latent crosslinking reagent to a particular protein in complex solutions. When activated, the crosslinking of the tagged protein to its nearest neighbors occurs without large-scale covalent modifications elsewhere in the complex. Recent technical advances in this methodology are described. The study of very large multiprotein complexes presents many technical challenges, including the elucidation of the organization of proteins and the overall architecture of the complex. Described in this report are improvements in a novel affinity crosslinking system developed recently, which allows the noncovalent delivery of an oxidative crosslinking reagent specifically to His6-tagged proteins. This allows contacts made by the tagged protein to be studied in the context of large complexes and in complex mixtures such as crude extracts.
Bound states of conical singularities in graphene-based topological insulators.

We investigate the electronic structure induced by wedge disclinations (conical singularities) in a honeycomb lattice model realizing Chern numbers $\ensuremath{\gamma}=\ifmmode\pm\else\textpm\fi{}1$. We establish a correspondence between the bound state of (i) an isolated ${\ensuremath{\Phi}}_{0}/2$ flux, (ii) an isolated pentagon ($n=1$) or heptagon ($n=\ensuremath{-}1$) defect with an external flux of magnitude $n\ensuremath{\gamma}{\ensuremath{\Phi}}_{0}/4$ through the center, and (iii) an isolated square or octagon defect without external flux, where ${\ensuremath{\Phi}}_{0}=h/e$ is the flux quantum. Because of the above correspondence, the existence of isolated electronic states bound to disclinations is robust against various perturbations. Hence, measuring these defect states offers an interesting probe of graphene-based topological insulators which is complementary to measurements of the quantized edge currents.
Optimal actuator/sensor placement for nonlinear control of the Kuramoto-Sivashinsky equation

In this paper, we use a methodology that was recently proposed by Antoniades and Christofides (2001) to compute the optimal actuator/sensor locations for the stabilization, via nonlinear static output feedback control, of the zero solution of the Kuramoto-Sivashinsky equation (KSE) for values of the instability parameter for which this solution is unstable. The theoretical results are illustrated through computer simulations of the closed-loop system using a high-order discretization of the KSE.
Synthesis of Composite Films

A new method for synthesis of composite films was developed and used to synthesize ZnO—SiO2 and Cu—SiO2 composite films where the silica particle size was varied from 40 nm to 520 nm. The process consists of sequential deposition of particles and the matrix material (using chemical vapor deposition) and can be used for any material system. The morphology of the composite films can be controlled and varied from dense to porous and laminated structures can be formed. The film formation process can be explained in terms of the Thiele modulus. In order to obtain dense films the Thiele modulus for such systems should be 1.5.
Effects of Pressure Drop in Horizontal Wells and Optimum Well Length

As the length of a horizontal well is increased, its contact with the reservoir increases. But at the same time, the resistance to flow in the well also increases, which has a direct negative effect on the productivity of the well. The overall performance of a horizontal well depends on the balance of these two opposing factors. No reliable tools are currently available that account for both these factors in the evaluation of horizontal well performance. A semi-analytical well-model is developed which can quantify the effects of both single phase oil and two-phase oil/gas flow pressure loss in the well on the overall well performance. The model is quite flexible and can incorporate any friction factor correlation. A methodology is developed to show the effects of various reservoir, fluid and well parameters on well productivity. We demonstrate that ignoring frictional effects could lead to unrealistically higher production estimates and low breakthrough times for water or gas. As a result of pressure drop in the well, breakthroughs occur first at the heel of the well. A methodology is also developed to calculate the optimum horizontal well length.
Application of the EPR spin-trapping technique to the detection of radicals produced in vivo during inhalation exposure of rats to ozone.

Abstract Ozone is known to induce lipid peroxidation of lung tissue, although no direct evidence of free radical formation has been reported. We have used the electron paramagnetic resonance (EPR) spin-trapping technique to search for free radicals produced in vivo by ozone exposure. The spin trap α-(4-pyridyl-1-oxide)- N-tert -butylnitrone (4-POBN) was administered ip to male Sprague-Dawley rats. The rats were then exposed for 2 hr to either 0, 0.5, 1.0, 1.5, or 2.0 ppm ozone with 8% CO 2 to increase their respiratory rate. A six-line 4-POBN/radical spin adduct signal ( a N = 15.02 G and a β H = 3.27 G) was detected by EPR spectroscopy in lipid extracts from lungs of rats treated with 4-POBN and then exposed to ozone. Only a weak signal was observed in the corresponding solution from rats exposed to 0 ppm ozone (air with CO 2 only). The concentration of the radical adduct increased as a function of ozone concentration. After administration of 4-POBN, rats were exposed for either 0.5, 1.0, 2.0, or 4.0 hr to either 0 or 2.0 ppm ozone (with CO 2 ). The radical adduct concentration of the ozone-exposed groups at exposure times of 2.0 and 4.0 hr was significantly different from that of the corresponding air control groups. A correlation was observed between the radical adduct concentration and the lung weight/body weight ratio. These results demonstrate that ozone induces the production of free radicals in rat lungs during inhalation exposure and that radical production may be involved in the induction of pulmonary toxicity by ozone. This is the first direct evidence for ozone-induced free radical production in vivo .
Knot Floer homology and rational surgeries

Let K be a rationally null-homologous knot in a three-manifold Y. We construct a version of knot Floer homology in this context, including a description of the Floer homology of a three-manifold obtained as Morse surgery on the knot K. As an application, we express the Heegaard Floer homology of rational surgeries on Y along a null-homologous knot K in terms of the filtered homotopy type of the knot invariant for K. This has applications to Dehn surgery problems for knots in S3. In a different direction, we use the techniques developed here to calculate the Heegaard Floer homology of an arbitrary Seifert fibered three-manifold with even first Betti number.
Value-based customer grouping from large retail data sets

In this paper, we propose OPOSSUM, a novel similarity-based clustering algorithm using constrained, weighted graph- partitioning. Instead of binary presence or absence of products in a market-basket, we use an extended 'revenue per product' measure to better account for management objectives. Typically the number of clusters desired in a database marketing application is only in the teens or less. OPOSSUM proceeds top-down, which is more efficient and takes a small number of steps to attain the desired number of clusters as compared to bottom-up agglomerative clustering approaches. OPOSSUM delivers clusters that are balanced in terms of either customers (samples) or revenue (value). To facilitate data exploration and validation of results we introduce CLUSION, a visualization toolkit for high-dimensional clustering problems. To enable closed loop deployment of the algorithm, OPOSSUM has no user-specified parameters. Thresholding heuristics are avoided and the optimal number of clusters is automatically determined by a search for maximum performance. Results are presented on a real retail industry data-set of several thousand customers and products, to demonstrate the power of the proposed technique.
Implications from Ithaca Chasma for the thermal and orbital history of Tethys

[1] Flexural modeling of Ithaca Chasma on Tethys suggests that the elastic thickness and the surface heat flux were 5–7 km and 18–30 mW/m2 respectively, when the feature formed (∼4 Gyr B.P.). Tidal heating is a plausible heat source, suggesting that Tethys' eccentricity was higher in the past. Depending on Tethys' internal structure, eccentricities in the range 0.001 to 0.02 are sufficient to have generated the inferred heat flux. Because the eccentricity damping timescale is short, <20 Myr, it is unlikely that this eccentricity was primordial. More likely, Tethys' eccentricity increased during passage through a 3:2 resonance with Dione. In equilibrium, this resonance produces ∼2.5 mW/m2 suggesting that non-equilibrium or periodic heating was important, similar to the case for Enceladus at present.
Highly effective synthesis of 4-halo-tetrahydropyrans via a highly diastereoselective in situ Prins-type cyclization reaction

Abstract The reaction of aldehyde with homoallyl alcohols mediated by indium trichloride generated 4-chlorotetrahydropyrans in high yields and with high stereoselectivity. The same type of compounds can be generated through a single step, multi-component coupling between aldehyde and allyl bromide mediated by indium
Reactivity of Mitsunobu reagent toward carbonyl compounds.

The nitrogen-based nucleophile generated from azodicarboxylate and triphenylphosphine displayed an excellent reactivity toward carbonyl compounds to generate a variety of different final products depending on the substituent pattern on the carbonyl carbon. From the structures of these adducts, a straightforward mechanistic interpretation for the formation of different products is provided.
The cotton commodity chain, women, work and agency in India and Japan: the case for feminist agro-food systems research.

Abstract This paper centers gender to advance alternative theoretical explanations in agro-food systems research and develops a methodology, feminist commodity chain research. The theory and methodology are put to work in the historical context of cotton in India and Japan to illuminate similitude and disruption when agrarian economies articulate with the global forces of colonialism. I then present a case study of contemporary south India to argue that a respect for history, differentiating between forms of transgressionary and feminist agency, and listening to women's theories, speak to the current disjuncture by acknowledging “winners,” “losers,” and new possibilities for women and workers.
LIFTING THE DUSTY VEIL WITH NEAR- AND MID-INFRARED PHOTOMETRY. III. TWO-DIMENSIONAL EXTINCTION MAPS OF THE GALACTIC MIDPLANE USING THE RAYLEIGH-JEANS COLOR EXCESS METHOD

We provide new, high-resolution A(K{sub s} ) extinction maps of the heavily reddened Galactic midplane based on the Rayleigh-Jeans Color Excess ({sup R}JCE{sup )} method. RJCE determines star-by-star reddening based on a combination of near- and mid-infrared photometry. The new RJCE-generated maps have 2' Multiplication-Sign 2' pixels and span some of the most severely extinguished regions of the Galaxy-those covered with Spitzer/IRAC imaging by the GLIMPSE-I, -II, -3D, and Vela-Carina surveys, from 256 Degree-Sign < l < 65 Degree-Sign and, in general, for |b| {<=} 1 Degree-Sign -1.{sup 0}5 (extending up to |b| {<=} 4 Degree-Sign in the bulge). Using RJCE extinction measurements, we generate dereddened color-magnitude diagrams and, in turn, create maps based on main sequence, red clump, and red giant star tracers, each probing different distances and thereby providing coarse three-dimensional information on the relative placement of dust cloud structures. The maps generated from red giant stars, which reach to {approx}18-20 kpc, probe beyond most of the Milky Way extinction in most directions and provide close to a 'total Galactic extinction' map-at minimum they provide high angular resolution maps of lower limits on A(K{sub s} ). Because these maps are generated directly from measurements of reddening by themore » very dust being mapped, rather than inferred on the basis of some less direct means, they are likely the most accurate to date for charting in detail the highly patchy differential extinction in the Galactic midplane. We provide downloadable FITS files and an IDL tool for retrieving extinction values for any line of sight within our mapped regions.« less
New Computational Methods for the Prediction and Analysis of Helicopter Noise

Abstract : This paper describes several new methods to predict and analyze rotorcraft noise. These methods are 1) a combined computational fluid dynamics and Kirchholt scheme for far-field noise predictions, 2) parallel computer implementation of the Kirchhoff integrations 3) audio and visual rendering of the computed acoustic predictions over large far-field regions, and 4) acoustic tracebacks to the Kirchhoff surface to pinpoint the sources of the rotor noise. The paper describes each method and presents sample results for three test cases. The first case consists of in-plane high-speed impulsive noise and the other two cases show idealized parallel and oblique blade-vortex interactions. The computed results show good agreement with available experimental data but convey much more information about the far-field noise propagation. When taken together, these new analysis methods exploit the power of new computer technologies and offer the potential to significantly improve our prediction and understanding of rotorcraft noise.
Sinusoidal Analysis-Synthesis of Audio Using Perceptual Criteria

This paper presents a new method for the selection of sinusoidal components for use in compact representations of narrowband audio. The method consists of ranking and selecting the most perceptually relevant sinusoids. The idea behind the method is to maximize the matching between the auditory excitation pattern associated with the original signal and the corresponding auditory excitation pattern associated with the modeled signal that is being represented by a small set of sinusoidal parameters. The proposed component-selection methodology is shown to outperform the maximum signal-to-mask ratio selection strategy in terms of subjective quality.
Cooperative Collision Warning Systems: Concept Definition and Experimental Implementation

The concept of cooperative collision warning (CCW) systems is introduced and explained, followed by presentation of experimental results showing the performance of a first prototype CCW system. The CCW concept provides warnings or situation awareness displays to drivers based on information about the motions of neighboring vehicles obtained by wireless communications from those vehicles, without use of any ranging sensors. This has the advantages of a potentially inexpensive complement of onboard vehicle equipment (compared to ranging sensors that could provide 360-degree coverage), as well as providing information from vehicles that may be occluded from direct line of sight to the approaching vehicle. The CCW concept has been tested on a fleet of five prototype vehicles, supporting a variety of safety services (forward collision warning, blind spot and lane change situation awareness, and several modes of intersection threat assessment). The performance of the vehicle position estimation and wireless communication subsystems are demonstrated using samples of experimental data from test sites with both good and bad Global Positioning System (GPS) signal availability.
RECENT DEVELOPMENTS ON THE RICCI FLOW

This article reports recent developments of the research on Hamilton's Ricci flow and its applications.
Structural modification and optical reflectivity of new gold–indide intermetallic compounds

Abstract The gold–indide SrAu 3.36(2) In 4.64 contains a novel 3D Au/In network, which can be described in terms of complex ∞ 3 [Au,In] 8 2− polyanions with strontium atoms filling hexagonal cages that are part of highly condensed infinite channels. This new intermetallic compound represents a small decrease in the indium content, i.e., as compared to SrAu 3.76(4) In 4.24 , and results in a significant orthorhombic to monoclinic structural transformation. Electronic structure calculations by Linear Muffin-Tin-Orbital (LMTO) methods show that Au–In interactions are predominant in its structural stabilization. UV–vis measurements show a generally lower reflectivity and higher absorption, as compared to elemental Au.
Imaging the solar cell P-N junction and depletion region using secondary electron contrast

We report on secondary electron (SE) images of cross-sectioned multicrystalline Si and GaAs/GaInP solar cell devices, focusing on quantifying the relationship between the apparent n+-p contrast and characteristic electronic features of the device. These samples allow us to compare the SE signal from devices which have very different physical characteristics: differing materials, diffused junction versus abrupt junction, heterojunction versus homojunction. Despite these differences, we find that the SE image contrast for both types of sample, and as a function of reverse bias across the diode, closely agrees with PC1D simulations of the bulk electrostatic potential in the device, accurately yielding the depletion edge and width. A spatial derivative of the SE data shows a local maximum at the metallurgical junction. Such data are valuable, for example, in studying the conformity of a diffused junction to the textured surface topography. These data also extend our understanding of the origin of the SE contrast.
Self-Assembly of a Threaded Molecular Loop

An efficient synthesis of a threaded molecular loop is described. The synthetic approach is notable in that it is a template-directed self-assembly process in aqueous solution. The structure of the threaded molecular loop is unprecedented since it is held intact solely by noncovalent interactions. This high yield, mild conditions, and convergent nature of the assembly process suggest that a variety of highly organized supramolecular entities can be efficiently prepared from appropriately designed subunits via noncovalent forces
A regression-based method for estimating relative permeabilities from displacement experiments

The authors address the process of estimating relative permeability curves from data collected during unsteady-state displacement experiments. They introduce B-splines for use as functional representations of relative permeability curves. With B-splines, polynomial splines of any order can be conveniently implemented in the estimation procedure. This feature allows greater flexibility for incorporating inequality constraints into the parameter-estimation process. The authors present a method for choosing an appropriate number of spline partitions for representing permeability curves. The method is based on considerations for obtaining the most accurate estimates of the relative permeability curves. They illustrate the method with both hypothetical and actual experimental data. They demonstrate that serious estimation errors may be encountered when relative permeability curves are represented with functions containing too few parameters - e.g., power-law functions.
Duration and frequency of telecenter use: once a telecommuter, always a telecommuter?

The study of temporal patterns of telecommuting is essential in understanding the adoption of telecommuting and, hence, the impacts of telecommuting on the demand for equipment and services as well as the demand for travel. This research examines, in the context of center-based telecommuting, how often individuals telecommute, the duration of their telecommuting participation, and causes of attrition among telecommuters. It also presents related findings from previous studies of home-based telecommuting. Attrition at the telecenters studied was relatively high, with 50% of all telecommuters quitting within the first 9 months. The average telecommuting frequency across the sample was 22% or about 1.1 days per week. Nearly 64% of the participants telecommuted less than 1 day per week on average. The relationship between frequency and duration appears to be complex, with partially counteracting trends. The results suggest that there is a stable segment of the sample (stayers) who are committed higher-frequency telecommuters, but that within the segment having a propensity to quit, there is a slight but statistically significant tendency for higher-frequency telecommuters to quit sooner. The motivations of participants for quitting the program were investigated. The most frequent type of reason given was job-related (cited by more than a third of all quitters). Other important reasons were supervisor-related (16%) and closure of the center (12%). No one cited dissatisfaction with telecommuting as a reason for quitting, and most quitters expressed a desire to continue telecommuting from the center.
Reformatsky reactions with propargyl bromide and Zn ? Cu couple

A Reformatsky-type reaction with propargyl bromide and ZnCu couple provides easy access to acetylenic carbinols, which can be converted into their iodo and bromo derivatives.
Light scattering from correlated ion fluctuations in ionic conductors

Abstract Inelastic light scattering spectra of CuI and AgI in the α and melt phases are reported and shown to involve two depolarized Lorentzian components centered at zero frequency. The narrow component is interpreted in terms of ionic motions and we propose that the observed depolarized scattering is caused by correlated configurations of the mobile ions.
Leak Before Break of CRA Tubing in Sour Environments

This paper demonstrates that net-section yielding controls the fracture of corrosion-resistant-alloy (CRA) tubulars. Fracture modes observed in actual tests of CRA tubes in sour environments agree with net-section yielding predictions. The paper also shows that leak before break of production tubing in certain sour environments can be achieved with commercially available CRA tubulars
A SHORT, ENANTIOSELECTIVE SYNTHESIS OF (-)-EPILUPININE FROM PROLINE VIA A SPIROCYCLIC AMMONIUM YLIDE

Abstract Diazoketone 5b, available in one step from proline benzyl ester, underwent conversion to quinolizidine 8b with high diastereoselectivity (19:1 8b/7b) and in surprisingly high enantiomeric excess (75%). The key step presumably occurs via spirocyclic ylide 6b, which undergoes [1,2]-shift with retention. Rearrangement product 8b was converted to (−)-epilupinine 2 via an efficient, 3-step sequence.
The theory, design, implementation and evaluation of a three-dimensional surface detection algorithm

In many three-dimensional imaging applications the three-dimensional scene is represented by a three-dimensional array of volume elements, or voxels for short. A subset Q of the voxels is specified by some property. The objects in the scene are then defined as subsets of Q formed by voxels which are “connected” in some appropriate sense. It is often of interest to detect and display the surface of an object in the scene, specified, say, by one of the voxels in it. In this paper, the problem of surface detection is translated into a problem of traversal of a directed graph, G. The nodes of G correspond to faces separating voxels in Q from voxels not in Q. It is proven that connected subgraphs of G correspond to surfaces of connected components of Q (i.e., of objects in the scene). Further properties of the directed graph are established which allow us to keep the number of marked nodes (needed to avoid loops in the graph traversal) to a small fraction of the total number of visited nodes. This boundary detection algorithm has been implemented. We discuss the interaction between the underlying mathematical theory and the design of the working software. We illustrate the software by some clinical studies in which the input is computed tomographic (CT) data and the output is dynamically rotating three-dimensional displays of isolated organs. Even though the medical application leads to very large-scale problems, our theory and design allows us to use our method routinely on the minicomputer of a CT scanner.
An empirical, path-oriented approach to software analysis and testing

Error flow analysis and testing techniques focus on the introduction of errors through code faults into data states of an executing program, and their subsequent cancellation or propagation to output. The goals and limitations of several error flow techniques are discussed, including mutation analysis, fault-based testing, PIE analysis, and dynamic impact analysis. The attributes desired of a good error flow technique are proposed, and a model called dynamic error flow analysis (DEFA) is described that embodies many of these attributes. A testing strategy is proposed that uses DEFA information to select an optimal set of test paths and to quantify the results of successful testing. An experiment is presented that illustrates this testing strategy. In this experiment, the proposed testing strategy outperforms mutation testing in catching arbitrary data state errors.
Stable Bromine and Activation Analysis in Protein Tracer Studies

ALTHOUGH the judicious use of radioisotopes such as iodine-131 and iodine-125 for tracing proteins in metabolic studies in man may result in very little iatrogenic exposure of the subject to radioactivity, a general method for labelling such proteins which would not expose the patient to even this small amount of radiation would be preferable, especially in infants and pregnant women. In the present investigation, the feasibility of using neutron activation in the study of the metabolism of proteins labelled with stable bromine, bromine-79 and bromine-81 was explored; the latter isotopes have suitable cross-sections for thermal neutron capture, bromine-79 being activated to bromine-80 (half-life of 4.4 h) and bromine-81 being activated to bromine-82 (half-life of 36 h) (ref. 1).
Direct Optimal Control of Nonlinear Systems Via Hamilton’s Law of Varying Action

Based on direct application of Hamilton's Law of Varying Action in conjunction with an assumed-time-modes approach for both the generalized coordinates and input functions, a direct optimal control methodology is developed for the control of nonlinear, time varying, spatially discrete mechanical systems. Expansion coefficients of admissible time modes for the dependent variables of the dynamic system and those for the inputs constitute the states and controls, respectively. This representation permits explicit a priori integration in time of the energy expressions in Hamilton's law and leads to the algebraic equations of motion for the system which replace the conventional differential state equations ; therefore the customary extremum principles of calculus of variations involving differential form constraints are also bypassed. Similarly, the standard integral form of the quadratic regulator performance measure employed in the formulation of the optimality problem is transformed into an algebraic performance measure via assumed-time-modes expansion of the generalized coordinates and the control inputs. The proposed methodology results in an algebraic optimality problem from which a closed-form explicit solution for the nonlinear feedback control law is obtained directly. Simulations of two nonlinear nonconservative systems are included.
The influence of elevated levels of sodium in drinking water on elementary and high school students in Massachusetts.

Abstract Continuing epidemiologic studies at the University of Massachusetts have examined the hypothesis that elevated levels of sodium (Na) in drinking water contribute to elevations of blood pressure (BP). Comparing tenth graders from a town with 107 mg Na/L in the drinking water to those from a town with 8 mg, Na/L, revealed statistically significant and medically important higher BP distributions among the high Na town students relative to their low Na town peers for both systolic and diastolic BP in both boys and girls. The differences were upheld when potentially confounding factors, including dietary Na intake and other water factors occurring differentially in the two water supplies, were controlled in the analysis. A replication study among third graders in the same communities showed similar results. Most recently, an experimental bottled water study assessed the effect on bloodpressure of lowering Na concentration in the water of some of the high sodium community fourth graders. For three months trios of children matched by sex, school, and baseline BP each used different water for all cooking and drinking purposes, with BP monitored bi-weekly. Pupils were randomly allocated to the three water conditions: 1) high sodium water bottled from their own community distribution system, 2) low sodium water bottled from the distribution system of the comparison community with sodium added to the level of the high sodium community water and 3) low sodium water bottled from the distribution system of the low sodium community but with no sodium added. Preliminary results indicate the BP levels of the girls on the low sodium waterexhibited marked decreases in BP over the test period when compared to the other two groups.
The covering lemma up to a Woodin cardinal

A cardinal kappa is countably closed if mu^omega < kappa whenever mu < kappa. Assume that there is no inner model with a Woodin cardinal and that every set has a sharp. Let K be the core model. Assume that kappa is a countably closed cardinal and that alpha is a successor cardinal of K with kappa < alpha < kappa^+. Then cf( alpha ) = kappa. In particular, K computes successors of countably closed singular cardinals correctly. (The hypothesis of countable closure is not required; see "Weak covering without countable closure", W. J. Mitchell and E. Schimmerling, Math. Res. Lett., Vol. 2, No. 5, Sept. 1995.)