cssi/SciSciGPT-SciSciNet huggingface dataset:
Querying logical databases

Abstract We study here the complexity of evaluating quaries in logical databases. We focus on Reither's model of closed-world databases with unknown values. We show that in this setting query evaluation is harder than query evaluation for physical databases. For example, while 1st-order queries over physical databases can be evaluated in logarithmic space, evaluation of 1st-order queries in the studied model is co-NP-complete. We describe an approximation algorithm for query evaluation that enables one to implement a logical database on the top of a standard database management system.
Westernization of Asian Diets and the transformation of food systems: Implications for research and policy

Abstract Rapid economic and income growth, urbanization, and globalization are leading to a dramatic shift of Asian diets away from staples and increasingly towards livestock and dairy products, vegetables and fruit, and fats and oils. While the diversification of diets away from the traditional dominance of rice with rising incomes is expected and observed, current food consumption patterns are showing signs of convergence towards a Western diet. The diet transition is characterized by increased consumption of: wheat; temperate fruit and vegetables and high protein and energy dense food. Globalization and the consequent global interconnectedness of the urban middle class, is the driving force behind the convergence of diets. The rapid spread of global supermarket chains and fast food restaurants is reinforcing the above trends. The growing demand for diet diversity cannot be met solely by the traditional food supply chain. It requires the modernisation of the food retail sector, and the vertical integration of the food supply chain, in effect linking the consumers’ plate to the farmers’ plow. As a consequence, Asian agriculture is on an irreversible path leading away from its traditional pre-occupation with cereal crop production, especially rice, towards a production system that is becoming increasingly commercialized and diversified. This paper describes the determinants and trends in the diversification and Westernization of Asian diets. Implications of the evolving demand trends for food supply and retail systems are presented. The paper discusses the prospects for small farmer participation in the emerging food supply system, with a particular emphasis on Asian rice production systems. Finally, the paper considers emerging challenges for food policy, small holder welfare, and agricultural research and development priorities.
Windows on the axion

Abstract Peccei-Quinn symmetry is a very compelling, and perhaps the most minimal, extension of the standard model, in that it provides a very elegant solution to the nagging strong CP problem associated with the Θ-vacuum structure of QCD. Peccei-Quinn symmetry is spontaneously broken at an energy scale ƒ PQ and as a consequence there should be a light, pseudo-scalar particle—the axion—whose mass m a ∝ ƒ PQ −1 . At present, particle physics gives little guidance as to the mass of the axion (equivalently ƒ PQ ); a priori, the plausible values span the range: 10 −12 eV ≲ m a ≲ 10 6 eV, some eighteen orders of magnitude. Laboratory experiments have excluded masses greater than about 10 4 eV, leaving unprobed some sixteen orders of magnitude. Fortunately, this very large “window” can—and has been—pared down by using the “Heavenly Laboratory”. Axions have a host of interesting astrophysical and cosmological effects, among them modifying the evolution of stars of all types (our sun, red giants, white dwarfs, and neutron stars), contributing significantly to the mass density of the Universe today, and producing detectable line radiation through the decays of relic axions. Consideration of these effects has probed fourteen orders of magnitude in axion mass, and has left open only two windows for further exploration: 10 −6 eV ≲ m a ≲ 10 −3 eV and 2 eV ≲ m a ≲ 5 eV (hadronic axions only). Both of these windows are accessible to heavenly experiments. and a variety of very interesting experiments are being planned or are underway.
SRAM dynamic stability estimation using MPFP and its applications

In this paper, an accurate approach for estimating the dynamic stability of static random access memory (SRAM) is proposed. The conventional methods of SRAM stability estimation suffer from two major drawbacks: (1) using static failure criteria, such as SNM, which does not capture the transient and dynamic behavior of SRAM operation, and (2) using quasi-Monte-Carlo simulation, which approximates the failure distribution, resulting in large errors at the tails where the desired failure probabilities exist. These drawbacks are eliminated by employing accurate simulation-based dynamic failure criteria along with a new distribution-independent, Most-probable-failure-point search technique for accurate probability calculation. Compared to previously published techniques, the proposed dynamic stability technique offers orders of magnitude improvement in accuracy. Furthermore, the proposed dynamic stability technique enables the correct evaluation of stability in real operation conditions and for different dynamic circuit techniques, such as dynamic write back, where the conventional methods are not applicable.
The Application of “Strain Range Partitioning Method” to Torsional Creep-Fatigue Interaction

The method of strain range partitioning was applied to a series of torsional fatigue tests conducted on tubular 304 stainless steel specimens at 1200 F (649 C). Creep strain was superimposed on cycling strain, and the resulting strain range was partitioned into four components; completely reversed plastic shear strain followed by creep strain, creep strain followed by plastic strain and completely reversed creep strain. Each strain component was related to the cyclic life of the material. The paper describes the experimental procedure used to achieve strain partitioning and the torsional test results are compared to those obtained from axial tests. The damaging effects of the individual strain components were expressed by a linear life fraction rule. The shear strain plastic component showed the least detrimental factor when compared to creep strain reversal by plastic strain. In the latter case, a reduction of torsional fatigue life in the order of magnitude of 1.5 was observed.
Modified long-period behavior due to tesseral harmonics.

Von Zeipel method and Hamiltonian perturbation mechanics used for orbits at resonance with tesseral harmonics of geopotential
On the stability of the geostatistical method

A thorough geostatistical analysis of spatial data, observed at given spatial locations, includes exploratory data analysis, spatial-model building, diagnosing the model fit, and inference on unknown model parameters or unobserved values (at known locations). Using results from mathematical analysis, exact and asymptotic distribution theory, and simulation studies, we argue that, when used sensibly, the geostatistical method is reassuringly stable.
Detectability of CMB tensor B modes via delensing with weak lensing galaxy surveys

We analyze the possibility of delensing cosmic microwave background (CMB) polarization maps using foreground weak lensing (WL) information. We build an estimator of the CMB lensing potential out of optimally combined projected-potential estimators to different source redshift bins. Our estimator is most sensitive to the redshift depth of the WL survey, less so to the shape noise level. Estimators built using galaxy surveys like the Large Synoptic Survey Telescope and the Supernova Acceleration Probe recover up to 80%-90% of the potential fluctuations power at l{ 20. The delensing gains are lost if the CMB beam exceeds {approx}20 arcmin. The delensing gains and useful z{sub max} depend acutely on the CMB map noise level, but beam sizes below 10 arcmin do not help. Delensing via foreground sources does not require arc-minute-resolution CMB observations, a substantial practical advantage over the use of CMB observables for delensing.« less
Nonrelativistic Kapitza-Dirac scattering

We use techniques of singular perturbation theory to investigate the scattering of nonrelativistic charged particles by a standing light wave (Kapitza-Dirac scattering). Unlike previous treatments, we give explicit results for the effects of the time-dependent part of the field. For low field intensity or low particle energy, we show that the leading-order effects can be found from an averaged equation, and we compute corrections. For the strong fields that can be produced by modern lasers and/or high particle energies, we show that the time dependence of the potential leads to focusing. Our methods can be applied to other problems with time-periodic potentials.
Atomic motion of dopant during interfacial silicide formation

Abstract The redistribution of implanted dopant atoms during silicide formation has attracted much interest recently because of its important implications for shallow junction device technology. Ion channeling and electrical measurements have shown that dopant atoms are pushed ahead in front of the moving silicide-silicon interface during the growth of near-noble metal silicides. However, dopant redistribution has not been observed with refractory metal silicides. This unique feature of near-noble metal silicides is discussed in conjunction with the growth kinetics of these silicides.
Precision navigation and timing enabled by microtechnology: Are we there yet?

This paper reviews currently recognized needs for advances in precision navigation and timing technology, summarizes ongoing efforts, and discusses future technological developments being pursued under the aggregated DARPA/MTO Microtechnology for Positioning, Navigation, and Timing (micro-PNT) program.
Cohesiveness, productivity, and wage dispersion

Abstract When work groups support the goals of the firm, firms will want to increase group cohesiveness. If narrowing wage dispersion increases cohesiveness, then companies will pay an efficiency wage to the low end of the wage distribution. This variant of efficiency wages predicts firm wage effects, and predicts that unemployment will be concentrated among low-wage workers. Furthermore, workers at cohesive firms will have higher marginal products than will similar workers at other firms; thus, policies to encourage the growth of cohesive firms will increase national output.
N =2 harmonic superforms, multiplets and actions

In this paper we develop the formalism to study superforms in N = 2 harmonic superspace. We perform a thorough (if not complete) analysis of the superforms starting from 0-form and moving all the way up to 6-form. Like the N = 1 case we find that the lower superforms (0,1,2,3) describe the various important N = 2 supermultiplets. Also, the forms form chains, the field strength of 0-form being related to the gauge form of the 1-form, and so on. However, an important difference with the N = 1 case is that there is now more than one chain. Our main aim was to study the higher-forms (4,5,6) to obtain the various N = 2 action formulas via the ectoplasmic approach. Indeed, we reproduce the three known action formulas involving a volume integral, a contour integral and no integral over the harmonic subspace from the 6, 5 and 4-form analysis, respectively. The next aim is to generalize the analysis to curved space-time (supergravity).
On the Role of Minor Galaxy Mergers in the Formation of Active Galactic Nuclei

The large-scale (~100 kpc) environments of Seyfert galaxies are not significantly different from those of non-Seyfert galaxies. In the context of the interaction model of the formation of active galactic nuclei (AGNs), it has thus been proposed that AGNs form via "minor mergers" of large disk galaxies with smaller companions. We test this hypothesis by comparing the nuclear spectra of 105 bright nearby galaxies with measurements of their R- or r-band morphological asymmetries at three successive radii. We find no significant differences between these asymmetries among the 13 Seyfert galaxies in the sample and galaxies having other nuclear spectral types (absorption, H II region-like, LINER), nor is there strong qualitative evidence that such mergers have occurred among any of the Seyfert galaxies or LINERs. Thus, either any minor mergers began 1 Gyr ago and are essentially complete, or they did not occur at all, and AGNs form independently of any type of interaction. Support for the latter interpretation is provided by the growing evidence that supermassive black holes exist in the cores of most elliptical and early-type spiral galaxies, which in turn suggests that nuclear activity represents a normal phase in the evolution of the bulges of massive galaxies. Galaxy mergers may increase the luminosity of Seyfert nuclei to the level of QSOs, which could explain why the latter objects appear to be found in rich environments and in interacting systems.
Impact of risk aversion and belief heterogeneity on trading of defaultable claims

This paper studies the problem of pricing and trading of defaultable claims among investors with heterogeneous risk preferences and market views. Based on the utility-indifference pricing methodology, we construct the bid-ask spreads for risk-averse buyers and sellers, and show that the spreads widen as risk aversion or trading volume increases. Moreover, we analyze the buyer’s optimal static trading position under various market settings, including (i) when the market pricing rule is linear, and (ii) when the counterparty—single or multiple sellers—may have different nonlinear pricing rules generated by risk aversion and belief heterogeneity. For defaultable bonds and credit default swaps, we provide explicit formulas for the optimal trading positions, and examine the combined effect of risk aversions and beliefs. In particular, we find that belief heterogeneity, rather than the difference in risk aversion, is crucial to trigger a trade.
Optimal Wireless Networks Based on Local Channel State Information

This paper considers distributed algorithms to optimize random access multihop wireless networks in the presence of fading. Since the associated optimization problem is neither convex nor amenable to distributed implementation, a problem approximation is introduced. This approximation is still not convex but it has zero duality gap and can be solved and decomposed into local subproblems in the dual domain. The solution method is through a stochastic subgradient descent algorithm that operates without knowledge of the fading's probability distribution and leads to an architecture composed of layers and layer interfaces. With limited amount of message passing among terminals and small computational cost, the proposed algorithm converges almost surely in an ergodic sense. Numerical results on a randomly generated network corroborate theoretical results.
Carbon nanotubes with single-layer walls

Macroscopic quantities of single-layer carbon nanotubes have recently been synthesized by co-condensing atomic carbon and iron group or lanthanide metal vapors in an inert gas atmosphere. The nanotubes consist solely of carbon, sp 2 -bonded as in graphene strips rolled to form closed cylinders. The structure of the nanotubes has been studied using high-resolution transmission electron microscopy. Iron group catalysts, such as Co, Fe, and Ni, produce single-layer nanotubes with diameters typically between 1 and 2 nm and lengths on the order of micrometers. Groups of shorter nanotubes with similar diameters can grow radially from the surfaces of lanthanide carbide nanoparticles that condense from the gas phase. If the elements S, Bi, or Pb (which by themselves do not catalyze nanotube production) are used together with Co, the yield of nanotubes is greatly increased and tubules with diameters as large as 6 nm are produced. Single-layer nanotubes are anticipated to have novel mechanical and electrical properties, including very high tensile strength and one-dimensional conductivity. Theoretical calculations indicate that the properties of single-layer tubes will depend sensitively on their detailed structure. Other novel structures, including metallic crystallites encapsulated in graphitic polyhedra, are produced under the conditions that lead to nanotube growth.
HBM tester waveforms, equivalent circuits, and socket capacitance

Abstract The Tektronix CT2 current probe is used to acquire more accurate Human Body Model waveforms with 0 Ω and 500 Ω tester loads than a CT1, owing to the CT2’s low-frequency performance. The integrals and centroids of these waveforms then readily yield precise values of tester circuit elements and effective socket capacitance. Expressions are derived for effective socket capacitance resulting from distributed capacitance along a transmission line connecting to an unmatched load. These lead to options for reducing the effective socket capacitance while retaining the lines for delivering the HBM pulse.
Numerical Simulation of Tip Clearance Effects in Turbomachinery

The numerical formulation developed here includes an efficient grid generation scheme, particularly suited to computational grids for the analysis of turbulent turbomachinery flows and tip clearance flows, and a semi-implicit, pressure-based computational fluid dynamics scheme that directly includes artificial dissipation, and is applicable to both viscous and inviscid flows. The value of this artificial dissipation is optimized to achieve accuracy and convergency in the solution. The numerical model is used to investigate the structure oftip clearance flows in a turbine nozzle. The structure of leakage flow is captured accurately, including blade-to-blade variation of all three velocity components, pitch and yaw angles, losses and blade static pressures in the tip clearance region. The simulation also includes evaluation of such quantities as leakage mass flow, vortex strength, losses, dominant leakage flow regions, and the spanwise extent affected by the leakage flow. It is demonstrated, through optimization of grid size and artificial dissipation, that the tip clearance flow field can be captured accurately.
Investment in manufacturing, exchange-rates and external exposure

Abstract This paper introduces a new measure of external exposure, which emphasizes exposure to external markets both through export sales and imported inputs into production, and uses this measure to explore the linkage between exchange rates and investment in US industry. On average, manufacturing sectors have evolved to being primarily import-exposed by the early 1980s. In low price-over-cost markup sectors, markups are relatively unresponsive to exchange rate changes, whereas sectoral investment patterns are strongly affected. By contrast, high markup industries absorb much of the exchange rate fluctuations in markups and pass relatively little through to real investment.
Proximity sensor technology for manipulator end effectors

Optical proximity sensing devices suitable for hand mounting on a manipulator are described, which use near IR LED light sources operating at 0.94 micron and silicon detectors, with appropriate signal processing so that the data are unaffected by ambient light. Laboratory tests with simple proximity sensors are described. Extension of the same techniques to yield multipoint or digital sensors is also discussed. A cooperative proximity sensor concept is described, which employs a composite mirror attached to the work piece to generate an unambiguous set of position and orientation signals. A very rudimentary experiment in local control of a manipulator with a pair of hand mounted proximity sensors is also described.
Very longwavelength lowpass interference filters

The extension of metallic mesh interference filter techniques to wavelengths longer than 2000 μm is discussed. The problems associated with design considerations and removal of leaks is considered in some detail. Successful filters were produced with edges at 6.3 cm−1 and 4.3 cm−1. When used in series and with a specific optical system, good rejection of unwanted radiation was achieved.
Kadell's two conjectures for Macdonald polynomials

This paper contains the proof of difference counterparts of the conjectures due to Keven Kadell on symmetric and anti-symmetric Macdonald polynomials.
Estimation of the density of regression errors

Estimation of the density of regression errors is a fundamental issue in regression analysis and it is typically explored via a parametric approach. This article uses a nonparametric approach with the mean integrated squared error (MISE) criterion. It solves a long-standing problem, formulated two decades ago by Mark Pinsker, about estimation of a nonparametric error density in a nonparametric regression setting with the accuracy of an oracle that knows the underlying regression errors. The solution implies that, under a mild assumption on the differentiability of the design density and regression function, the MISE of a data-driven error density estimator attains minimax rates and sharp constants known for the case of directly observed regression errors. The result holds for error densities with finite and infinite supports. Some extensions of this result for more general heteroscedastic models with possibly dependent errors and predictors are also obtained: in the latter case the marginal error density is estimated. In all considered cases a blockwise-shrinking Efromovich-Pinsker density estimate, based on plugged-in residuals, is used. The obtained results imply a theoretical justification of a customary practice in applied regression analysis to consider residuals as proxies for underlying regression errors. Numerical and real examples are presented and discussed, and the S-PLUS software is available.
Stereospecific Friedel-Crafts alkylation of benzene with 4-mesyloxy-L-prolines. A new synthesis of 4-phenylprolines

Abstract The reaction of benzene with cis - and trans -N-benzoyl-4-mesyloxy-L-proline ( 11 and 12 ) in the presence of AlCl 3 stereospecifically produces the corresponding trans - and cis -4-phenylproline derivatives.
Benzofurans. Ketene intermediates in the perkin reaction

The intermediacy of ketenes in the intramolecular reaction of ketoacids with sodium acetate in acetic anhydride to form benzofurans is demonstrated. The Perkin reaction conditions are superior to the classical ketene generation method of triethylamine dehydrochlorination of the acid chloride.
Does operating performance really improve following corporate acquisitions

Abstract Previous research indicates that operating performance improves following corporate acquisitions relative to industry-median firms. Such performance results are likely to be biased because acquiring firms undertake acquisitions following a period of superior performance and they are generally larger than industry-median firms. Using firms matched on performance and size as a benchmark, I find no evidence that operating performance improves following acquisitions. I also analyze if performance is higher in cash acquisitions as suggested by various studies. The results indicate that cash flows increase significantly following acquisitions that are made with cash, but decline for stock acquisitions.
Dark Force Detection in Low Energy e-p Collisions

We study the prospects for detecting a light boson X with mass mX ≾ 100 MeV at a low energy electron-proton collider. We focus on the case where X dominantly decays to e+e− as motivated by recent “dark force” models. In order to evade direct and indirect constraints, X must have small couplings to the standard model (αX ≾ 10−8) and a sufficiently large mass (mX ≳ 10 MeV). By comparing the signal and background cross sections for the e−p e+e− final state, we conclude that dark force detection requires an integrated luminosity of around 1 ab−1, achievable with a forthcoming JLab proposal.
The adolescent pragmatics screening scale: A comparison of language‐impaired students, bilingual/Hispanic students, and regular education students

This study compares the pragmatic performance of adolescent students from three groups: language‐impaired students, bilingual/limited‐English‐proficient (LEP) students, and regular education students. A developed pragmatic screening scale (i.e., Adolescent Pragmatics Screening Scale) was used to measure pragmatic performance. The findings of this study indicate that the language‐impaired students had difficulty expressing themselves, establishing greetings, initiating and maintaining conversations, and listening to a speaker. These difficulties may place language‐impaired students at risk for failure to follow and complete classroom lessons and failure to participate in classroom discussions. Bilingual/Hispanic students had difficulties making requests of others and listening to a speaker. These difficulties may place the bilingual/Hispanic students at risk for failure in cooperative learning situations in the classroom. Implications of this study for the speech‐language pathologist and for future researc...
Reverend Charles to the aid of Major Percy and Fields-Medalist Enrico

Voltaire said that Archimedes had more imagination than Homer. Unfortunately, most of mathematicians' creativity can be appreciated only by mathematicians themselves. Sometimes, however, mathematicians employ their imagination to do non-mathematical activity. Notable examples are Multi-Millionaire Richard Garfield, the Reverend Charles Dodgson, and Major Percy MacMahon, who respectively developed: 'Magic: The Gathering' (the game of our decade), Alice, and an early version of Instant Insanity. This is not to say that their imagination did not also help mathematics proper. In this quickie, I observe how Dodgson's rule for evaluating determinants [D] (for any n x n matrix A, let Ar(k, I) be the r x r submatrix whose upper leftmost corner is the entry ak l),
The making of the USA Patriot Act I: The legislative process and dynamics

Abstract On September 11, 2001, terrorists attacked America without warning, killing 2752 in New York City alone. The President declared war on terrorism and pledged to use all resources at United States’ disposal to conquer the enemy. On October 26, 2001, President Bush signed into law the USA PATRIOT ACT, giving the law enforcement officials expansive powers and security agencies increased resources to fight terrorism, at home and abroad. A cursory review of the legal literature shows that the USA PATRIOT ACT was “rushed” passed Congress by the Bush administration without following the usual legislative procedure. Throughout the entire legislative process, neither the Congress nor the Administration has systematically investigated and critically debated the merit—necessity and efficacy, costs and benefits, and the impact and implications of the ACT on the Constitution, on the society, on the people. More mystifyingly, neither the general public nor the mass media took the government to task for a want of due diligence in scrutinizing the ACT. How could this have happened? To date, no serious attempt has been made to explain how and why the USA PATRIOT ACT was adopted without any serious contest and effective challenge. This is a first attempt to do so. This article, based on a larger research project (“The Impact and Implications of USA PATRIOT Act on American Society”) investigated into the legislative history of the USA PATRIOT ACT, broadly defined. This article is first of a two part series reporting upon: “The Making of the USA PATRIOT ACT”. It is subtitled: “Legislative Process and Dynamics”. The article to follow is subtitled: “Public sentiments, legislative climate, political gamesmanship, media patriotism.” This article examined the Congressional records, tracked the floor debates and monitored newspaper accounts to document the process and detail the dynamics as to how the USA PATRIOT ACT was passed. The subsequent article would be looking into the public sentiments, legislative climate, political gamesmanship and media patriotism attending to and accounting for USA PATRIOT ACT's speedy and uncritical passage.
Graviton-Scalar Interaction in the pp-Wave Background

We compute the graviton two scalar off-shell interaction vertex at tree level in Type IIB superstring theory on the pp-wave background using the light-cone string field theory formalism. We then show that the tree level vertex vanishes when all particles are on-shell and conservation of p+ and p- are imposed. We reinforce our claim by calculating the same vertex starting from the corresponding SUGRA action expanded around the pp-wave background in the light-cone gauge.
DISTINGUISHED LINE BUNDLES FOR COMPLEX SURFACE AUTOMORPHISMS

We equate dynamical properties (e.g., positive entropy, existence of a periodic curve) of complex projective surface automorphisms with properties of the pull-back actions of such automorphisms on line bundles. We use the properties of the cohomological actions to describe the measures of maximal entropy for automorphisms with positive entropy.
Giacobinid Meteors in 1939 and 1940

On October 9, 1933, when the earth passed through the region occupied eighty days earlier by the faint, short-period comet Giacobini-Zinner, the strongest meteor shower of the century appeared for a few hours. The best available orbit for the comet indicates that it will again pass near the earth's orbit on February 23, 1940; thus in 1939 the earth will precede the comet to the nodal point by 136 days and in 1940 follow it by 229 days. It therefore appears probable that some recurrence of the shower, but of a quite unpredictable intensity, may be anticipated on October 9 or 10 in either or both of these years1. Observations from widely separated localities are of great value in the investigation of the internal structure of meteoric swarms, hence a request is made for reports from anyone detecting the shower. The radiant will be in the head of the constellation Draco, north and west of the bright star Vega. In 1939 the moon, aged twenty-five days, will not interfere; but in 1940, aged eight days, it will illuminate the evening sky.
On the Linearized Balescu–Lenard Equation

The Balescu–Lenard equation from plasma physics is widely considered to include a highly accurate correction to Landau's fundamental collision operator. Yet so far it has seen very little mathematical study. We perform an extensive linearized analysis of this equation, which includes determining the asymptotic behavior of the new components of the linearized operator and establishing time decay rates for the linearized equation.
TOTAL CROSS SECTIONS OF PROTONS, ANTIPROTONS, $pi$ MESONS AND K MESONS ON HYDROGEN AND DEUTERIUM IN THE MOMENTUM RANGE 6-22 Gev/c

The total cross sections ${\ensuremath{\sigma}}_{T}$ of $p$, $\overline{p}$, ${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$, and ${K}^{\ifmmode\pm\else\textpm\fi{}}$ on hydrogen and deuterium have been measured between 6 and 22 $\frac{\mathrm{GeV}}{c}$ at intervals of $2\frac{\mathrm{GeV}}{c}$ to an accuracy greater than previously reported. The method utilized was a conventional good-geometry transmission experiment with scintillation counters subtending various solid angles at targets of liquid ${\mathrm{H}}_{2}$ and ${\mathrm{D}}_{2}$. With the increase in statistical accuracy of the data, it was found that a previously adopted procedure of linearly extrapolating to zero solid angle the partial cross sections measured at finite solid angles was not a sufficiently accurate procedure from which to deduce ${\ensuremath{\sigma}}_{T}$. The particle-neutron cross sections are derived by applying the Glauber screening correction to the difference between the particle-deuteron and particle-proton cross sections. The cross sections ${\ensuremath{\sigma}}_{T}({\ensuremath{\pi}}^{+}d)$ and ${\ensuremath{\sigma}}_{T}({\ensuremath{\pi}}^{\ensuremath{-}}d)$ are equal at all measured momenta, which confirms the validity of charge symmetry up to $20\frac{\mathrm{GeV}}{c}$. Results are presented showing the variation of cross sections with momentum; evidence is presented for a small but significant decrease in ${\ensuremath{\sigma}}_{T}(\mathrm{pp})$ [and ${\ensuremath{\sigma}}_{T}(\mathrm{pn})$] in the momentum region above $12\frac{\mathrm{GeV}}{c}$.
Public grid computing participation: An exploratory study of determinants

Using the Internet, ''public'' computing grids can be assembled using ''volunteered'' PCs. To achieve this, volunteers download and install a software application capable of sensing periods of low local processor activity. During such times, this program on the local PC downloads and processes a subset of the project's data. At the completion of processing, the results are uploaded to the project and the cycle repeats. Public grids are being used for a wide range of endeavors, from searching for signals suggesting extraterrestrial life to finding a cure for cancer. Despite the potential benefits, however, participation has been relatively low. The work reported here, drawing from technology acceptance and volunteer literature, suggests that the grid operator's reputation, the project's perceived need, and the level of volunteering activity of the PC owner are significant determinants of participation in grid projects. Attitude, in addition to personal innovativeness and level of volunteering activity, predicted intentions to join the project. Thus, methods traditionally used for motivating volunteer behavior may be effective in promoting the use of grid computing.
First order quark - gluon / hadron transition may affect cosmological nucleosynthesis

Abstract In a model of a first order quark-gluon/hadron phase transition in which the hadronic phase is considered as vacuum bubbles growing in the quark-gluon background with chiral symmetry broken inside the bubble, we find the estimate for the length scale associated with inhomogeneities originated during the transition, 10 m ≲ l ≲ 40 m, being sufficient to produce significant effects on cosmological nucleosynthesis.
New approaches in heteroepitaxy and related devices

Abstract In recent years epitaxy without close lattice matching has become rather popular. This allows an additional degree of freedom to tailor the heterojunction properties among others which are finding their niches. In this paper three cases will be reviewed. One case deals with a compound semiconductor on an elemental semiconductor having very small lattice mismatch, a case in point being the interesting GaAs/Ge/GaAs system. The second one has to do with compound semiconductors on elemental Si with substantial lattice mismatch. Examples are GaAs, InP, GaSb and InSb on Si substrates. The third case deals with heterojunction systems that would normally exhibit lattice mismatch in their relaxed state. Grown very thin, below a critical thickness, these systems are coherent but strained. For example the InGaAs/(Al,Ga) As system which has been used to produced very high frequency devices and high quality low threshold and/or high power lasers, falls into this category.
Exotics and all that

This invited contribution summarizes some of the more important aspects of exotics. We review theoretical expectations for exotic and nonexotic hybrid mesons, and briefly discuss the leading experimental candidate for an exotic, the $\pi_1(1600)$ .
Conservation of the D-Mannose-Adhesion Protein Among Type 1 Fimbriated Members of the Family Enterobacteriaceae

A variety of genera and species of the family Enterobacteriaceae bear surface fimbriae that enable them to bind to D-mannose residues on eukaryotic cells. Until recently, it was thought that the D-mannose binding site was located in the major structural subunit (FimA), of relative molecular mass (Mr) 17,000 (17 K), of these organelles in Escherichia coli. New evidence indicates that this binding site resides instead in a minor protein Mr 28-31 K (FimH) located at the tips and at long intervals along the length of the fimbriae, and is reminiscent of the minor tip adhesion proteins of pyelonephritis-associated pili (Pap) and S fimbriae. In contrast to the antigenic heterogeneity of the major FimA subunit, the antigenic structure of FimH is conserved among different strains of E. coli. Here, we report an even broader conservation of this minor adhesion protein extending to other genera and species of type 1 fimbriated Enterobacteriaceae. Our results may have implications for the development of broadly protective vaccines against Gram-negative bacillary infections in animals and perhaps in man.
Soft X-ray diffraction tomography: Simulations and first experimental results

Diffraction tomography allows us to obtain high-resolution 3D phase and amplitude reconstructions of thick specimens. Here we report on some difficuties arising in the experimental realization of diffraction tomography. These initial experiments together with computer simulations are presented and first results obtained by incorporating the suggested modifications are shown for a collection of μm diameter latex spheres and a 3 μm diameter gold dot.
Influence of temperature and humidity on adhesion of underfills for flip chip packaging

This paper systematically discusses the influence of temperature and humidity on the adhesion performance of underfill material (epoxy cured with acid anhydride), which was evaluated by die shear test after exposure to various conditions. The inherent adhesion strength between the underfill and passivation is not affected significantly by thermal cycling between -55/spl deg/C and 125/spl deg/C for 1000 cycles. The adhesion strength of underfill material decreases with the increase of test temperature in the investigated range, due to the decrease of modulus of the underfill with the increase of temperature. A sharp decrease in adhesion strength occurs as temperature increases toward the glass transition temperature of the underfill material. Adhesion strength of underfill with different passivation materials decreases after aging in a high temperature and high humidity environment. The extent of the decrease depends on underfill formulation and the hydrophilicity of the passivation material. Hydrophilic passivation such silicon oxide (SiO/sub 2/) and silicon nitride (Si/sub 3/N/sub 4/) shows much more severe adhesion degradation than hydrophobic passivation such as benzocyclobutene (BCB) and polyimide (PI). Adhesion degradation is slower than moisture diffusion. The adhesion stability for hydrophilic passivation can be successfully improved by use of a coupling agent such as silane that introduces stable chemical bonds at interface.
Ionization efficiencies for highly charged stable and radioactive ions in the AECR-U ion source

Abstract Ionization efficiencies for high charge state ions have been measured with the LBNL AECR-U ion source for ion beams produced from stable and radioactive gases. Various calibrated gas leaks from stable CO, CO2, O2, Ne, Ar, CHF3, Kr and Xe were used in the measurements. Ionization efficiencies as high as 25% or higher were measured for 16O6+ and 12C4+ ion beams and more than 10% for high charge state stable ion beams of Ar, Kr and Xe. In addition, ionization efficiency measurements for radioactive species of 11C and 14O were carried out in which an efficiency of more than 10% for 11C4+ was achieved.
Synthetic Approaches to 5:8-Fused Heterocyclic Systems. A Novel Rearrangement During the Synthesis of Imidazo[4,5-e][1,2,4]triazocine Ring System

Abstract The attempted ring-closure of 4-amino-1-benzyl-5-[(N2-benzyl-N2-methoxy-carbonyl)hydrazinomethylenecarbonyl]imidazole (5b) in sodium hydride/dimethyl sulfoxide at 50–60 °C afforded 1,7-dibenzylxanthine (6) instead of the anticipated 5:8-fused heterocycle 4b. A tentative reaction pathway has been proposed for the observed transformation.
Rh-Catalyzed Intermolecular Reactions of Alkynes with α-Diazoesters That Possess β-Hydrogens: Ligand-Based Control over Divergent Pathways

A general method for Rh-catalyzed cyclopropenation is described, as is a Rh-catalyzed intermolecular alkyne insertion/Buchner ring expansion cascade. Ligand choice governs control over these divergent reaction pathways.
Incentive auctions and information revelation

We study an incentive auction in which multiple principals bid for the exclusive services, or effort, of a single agent. Each principal has private information about her valuation for these services, and the agent has private information about his disutility of providing them. We characterize the equilibrium of this auction and examine the agent's incentives to reveal information about his type. We show that the effort level taken by the agent is smaller than in the standard auction for a known agent type and greater than in the single-principal, single-agent model. Additionally, inexperienced analysts are less likely to issue timely forecasts, and they revise their forecasts more frequently. These findings are broadly consistent with existing career concern motivated herding theories.
Catalytic Asymmetric γ-Alkylation of Carbonyl Compounds via Stereoconvergent Suzuki Cross-Couplings

With the aid of a chiral nickel catalyst, enantioselective γ- (and δ-) alkylations of carbonyl compounds can be achieved through the coupling of γ-haloamides with alkylboranes. In addition to primary alkyl nucleophiles, for the first time for an asymmetric cross-coupling of an unactivated alkyl electrophile, an arylmetal, a boronate ester, and a secondary (cyclopropyl) alkylmetal compound are shown to couple with significant enantioselectivity. A mechanistic study indicates that cleavage of the carbon–halogen bond of the electrophile is irreversible under the conditions for asymmetric carbon–carbon bond formation.
Logarithmic operators in conformal field theory

Conformal field theories with correlation functions which have logarithmic singularities are considered. It is shown that those singularities imply the existence of additional operators in the theory which together with ordinary primary operators form the basis of the Jordan cell for the operator L0. An example of the field theory possessing such correlation functions is given.
Survival among U.S. women with invasive epithelial ovarian cancer.

Abstract Objective. Invasive epithelial ovarian cancer is a highly fatal disease, diagnosed at advanced stages when survival is poor. Relatively little is known about the variation in survival across U.S. women of different race/ethnicities. To investigate this issue, we evaluated pathological characteristics and death rates due to invasive epithelial ovarian cancer in a population-based sample of patients from six racial/ethnic groups. Methods. The analysis included 38,012 women diagnosed with primary invasive epithelial ovarian cancer between 1973 and 1997 in the Surveillance, Epidemiology and End Results Program of the National Cancer Institute. Results. Filipina patients were younger at diagnosis, more likely to have localized disease, and had more mucinous cancers than whites. African-Americans were more likely than whites to be diagnosed at older ages, with distant disease and with undifferentiated/unclassified cancers. After adjusting for age at diagnosis, stage of disease at diagnosis, and cancer histology, we found that, compared to whites, death rates were significantly elevated among African-Americans and significantly reduced among Hispanics and Filipina. We also found that death rates declined significantly with time since diagnosis among women with advanced disease. Conclusion. The declining death rates in women with advanced disease suggest the presence of considerable prognostic heterogeneity among these women, which could reflect differences in quality of care. This issue, as well as the survival disadvantage for African-American women and survival advantages for Hispanic and Filipina women, needs investigation.
A novel clay-based catalytic material—preparation and properties

Abstract A novel acid-leached calcined kaolin has been prepared by careful control of the calcination and acid leach conditions. A narrow calcination window gives an extremely acid-reactive calcined kaolin, which develops high surface areas at a rate much faster than that of samples calcined outside this range. This more acid active calcined kaolin also allows the use of extremely low levels of acid, which results in most of the alumina being in the solid phase during the entire leach step. Al 27 NMR results indicate the most acid-reactive calcined clay has the lowest level of octahedral and the highest level of five-coordinate Al. Acids containing anions that do not complex with aluminum such as hydrochloric, nitric, or aluminum chloride work in this process, while acids containing anions that complex with aluminum such a sulfuric or phosphoric do not lead to the same high surface area, catalytically active products. Properly calcined and leached materials show a broad distribution of pores centered at about 40 A.
Infrared radiometry of thermal transients on surfaces: An approach to the study of thermal effects caused by gas-solid interactions

Abstract A radiometer was used to study the sorption of O2 on SiO2-supported Ni. The measurements are based on the premise that the energy produced by the gas-solid interaction heats the surface of the solid, the radiation emitted by the heated surface then being detected. Rapid thermal transients were observed. The method and some preliminary results are discussed.
Palladium-catalyzed silylation of aryl bromides leading to functionalized aryldimethylsilanols.

A mild and general palladium-catalyzed insertion of 1,2-diethoxy-1,1,2,2-tetramethyldisilane into a variety of aryl bromides affords the aryldimethylsilyl ethers in high yields. Hydrolysis of the ethers under pH-optimized conditions results in the exclusive formation of the desired aryldimethylsilanols.
On the Formation of Gas Giant Planets on Wide Orbits

A new suite of three-dimensional radiative, gravitational hydrodynamical models is used to show that gas giant planets are unlikely to form by the disk-instability mechanism at distances of ~100-200 AU from young stars. A similar result seems to hold for the core accretion mechanism. These results appear to be consistent with the paucity of detections of gas giant planets on wide orbits by infrared imaging surveys, and they also imply that if the object orbiting GQ Lupus is a gas giant planet, it most likely did not form at a separation of ~100 AU. Instead, a wide planet around GQ Lup must have undergone a close encounter with a third body that tossed the planet outward to its present distance from its protostar. If it exists, the third body may be detectable by NASA's Space Interferometry Mission.
Optical interconnection using photorefractive dynamic holograms

On decrit une nouvelle methode pour definir une nouvelle configuration des interconnexions optiques en utilisant des hologrammes dynamiques dans des cristaux photorefractifs
Indirect observation of unobservable interstellar molecules.

It is suggested that the abundances of neutral non-polar interstellar molecules unobservable by radio astronomy can be systematically determined by radio observation of the protonated ions. As an example, observed N2H(+) column densities are analyzed to infer molecular nitrogen abundances in dense interstellar clouds. The chemistries and expected densities of the protonated ions of O2, C2, CO2, C2H2 and CH4 are then discussed. Microwave transition frequencies fo HCO2(+) and C2H3(+) are estimated, and a preliminary astronomical search for HCO2(+) is described.
The Synthesis of Amidine Acetals as Intermediates for the Preparation of Naturally Occurring Cyclic Amidine Antibiotics

Abstract Regioselective 1,3-dipolar cycloaddition of (phenylsulfonyl)nitrile oxide to acrolein dimethylacetal gave the isoxazole 3. Nucleophilic displacement of the phenylsulfonyl moiety followed by reductive N-O bond cleavage gave the amidine acetal 6.