cssi/SciSciGPT-SciSciNet huggingface dataset:
MOSS: multiple orthogonal strand system

This paper describes an overset approach that comprised virtual boundary-layer-like near-body grid coupled with an off-body adaptive mesh refinement far-field mesh for viscous fluids simulations. Unlike most a priori grid generation systems for the Reynolds-Averaged Navier---Stokes equations, the strand meshing paradigm is automatic, fast and requires little memory to provide boundary-layer coverage. In addition, the stacks of elements implied by the strands can be used to the simulation's advantage, where they naturally provide a line direction for semi-implicit solving.
Chemoselective construction of substituted conjugated dienes using an olefin cross-metathesis protocol.

Various substituted conjugated dienes have been made by olefin cross-metathesis. Using either electronic or steric “protection,” one of the olefins of the conjugated diene was deactivated relative to the other for cross-metathesis. The reactions proceed with very high chemoselectivity and, when steric deactivation is used, very high diastereoselectivity.
Using home buyers’ revealed preferences to define the urban–rural fringe

The location of new homes defines the urban–rural fringe and determines many facets of the urban–rural interaction set in motion by construction of new homes in previously rural areas. Home, neighborhood and school district characteristics play a crucial role in determining the spatial location of new residential construction, which in turn defines the boundary and spatial extent of the urban–rural fringe. We develop and apply a spatial hedonic variant of the Blinder (J Hum Resour 8:436–455, 1973) and Oaxaca (Int Econ Rev 9:693–709, 1973) price decomposition to newer versus older home sales in the Columbus, Ohio metropolitan area during the year 2000. The preferences of buyers of newer homes are compared to those who purchased the nearest neighboring older home located in the same census block group, during the same year. Use of the nearest older home purchased in the same location represents a methodology to control for various neighborhood, social–economic-demographic and school district characteristics that influence home prices. Since newer homes reflect current preferences for home characteristics while older homes reflect past preferences for these characteristics, we use the price differentials between newer and older home sales in the Blinder–Oaxaca decomposition to assess the relative significance of various house characteristics to home buyers.
Formation of Disubstituted β-Lactones Using Bifunctional Catalysis

Acid chlorides and aromatic aldehydes react in the presence of a stoichiometric amount of a tertiary amine and catalytic amounts of a cinchona alkaloid derivative and a Lewis acid to produce β-lactones in high diastereo- and enantioselectivity. The sense of the diastereoselectivity depends on the substitution of the acid chloride, with the reactions of aliphatic acid chlorides giving predominantly the trans-isomer and those of alkoxyacetyl chlorides favoring formation of the cis-isomer.
Thermal alteration of nontronite and montmorillonite: Implications for the martian surface

Abstract To test the effects of meteorite impacts on martian phyllosilicate deposits, we heated two smectites (nontronite and montmorillonite) to temperatures ranging from 350 °C to 1150 °C for durations of 4–24 h in two different atmospheres, under air and a steady flow of CO 2 . Samples were analyzed using X-ray diffraction (XRD) and near-infrared (NIR) and mid-infrared (MIR) reflectance spectroscopy. Interlayer water was lost after heating to temperatures of ∼400 °C. Between 400 °C and 700 °C, nontronite converted to an intermediary phase which conserved the XRD pattern of untreated nontronite with the exception of the 0 0 1 peak. Nanocrystalline high-temperature phases formed for both smectites at temperatures between 700 °C and 1000 °C. Finally, after being heated to temperatures above ∼1100 °C, the samples melted and recrystallized into secondary phases. Secondary high-temperature phases included sillimanite and cristobalite for both smectites plus hematite for nontronite. NIR and MIR reflectance spectra significantly evolved with increasing temperature. NIR spectra of smectites showed that 1.4 and 1.9 μm bands decrease in intensity and disappear above 700 °C. Similarly, the 2.2–2.3 μm metal–OH band showed a decrease in intensity as well as an overall shift towards lower wavelengths (for nontronite) due to the thermal resistance of the Al–OH bond compared to the Fe–OH bond. NIR spectra of montmorillonite showed a gradual increase in band depth up to temperatures between 500 °C and 600 °C, then decreased with increasing temperature. In the MIR spectra of samples heated to temperatures above ∼1100 °C, newly formed bands confirmed the secondary phases identified by XRD. Similarities between the NIR spectra of our heated samples and the phyllosilicates in some martian craters imply that these phyllosilicates were altered by the impact-generated heat and thus were not formed post-impact. In addition, NIR reflectance spectra provide a proxy for shock temperatures of smectites up to 700 °C while MIR is optimum for identification of high-temperature phases of smectites above 700 °C.
Orbit determination using dual crossing arc altimetry

Accurate knowledge of the position of an altimetric satellite is required for the altimeter range data to be effective in measuring ocean topography. This study addresses the use of high-precision altimeter data from NASA's TOPEX Mission in reducing the radial component of the orbit of the U.S. Navy's N-ROSS satellite. Simulated altimeter crossing arc residuals between the TOPEX and N-ROSS orbits are minimized using both geometric and dynamic techniques in an effort to reduce the N-ROSS radial error to a level comparable to that of TOPEX. Tracking of N-ROSS by the Navy's NAVSPASUR system is simulated, and crossover residuals are created from the TOPEX and N-ROSS orbits. A simple geometric fit is shown to reduce the radial component of the NAVSPASUR N-ROSS orbit error from 350 m RMS to below 10 m RMS. In comparison, the dynamic approach of estimating the initial conditions of the N-ROSS orbit using a twentieth degree and order gravity field and a combined data set of tracking and altimeter crossover data yields a 6 m RMS residual error. Sub-meter accuracy can be attained by geometrically fitting these residuals to remove long wavelength orbit error.
New examples of non-symmetric Einstein solvmanifolds of negative Ricci curvature

We obtain new examples of non-symmetric Einstein solvmanifolds by combining two techniques. In Tamaru (Parabolic subgroups of semisimple Lie groups and einstein solvmanifolds. Math Ann 351(1):51–66, 2011) constructs new attached solvmanifolds, which are submanifolds of the solvmanifolds correspond to noncompact symmetric spaces, endowed with a natural metric. Extending this construction, we apply it to associated solvmanifolds, described in (Ann Global Anal Geom 19(1):75–101, 2001), obtained by modifying the algebraic structure of the solvable Lie algebras corresponding to noncompact symmetric spaces. Our new examples are Einstein solvmanifolds with nilradicals of high nilpotency, which are geometrically distinct from noncompact symmetric spaces and their submanifolds.
Approximations for hypervelocity nonequilibrium radiating, reacting,and conducting stagnation regions

An approximate solution which includes the effects of chemical and thermal nonequilibrium and nonequilibrium nongray radiative transfer and which is suitable for rapidly obtaining approximate solutions for flowfield structure and estimates of radiative heat transfer is presented. Comparisons are made with Fire 2 data and example applications to a hypothetical Mars return AOTV are presented. Parametric results indicate that further studies of VUV processes and radiation models are needed.
Derived length and products of conjugacy classes

Let G be a supersolvable group and A be a conjugacy class of G. Observe that for some integer η(AA−1) > 0, AA−1 = {ab−1: a, b ∈ A} is the union of η(AA−1) distinct conjugacy classes of G. Set CG(A) = {g ∈ G: ag = a for all a ∈ A. Then the derived length of G/CG(A) is less or equal than 2η(AA−1) − 1.
Detecting neglected parameter heterogeneity with Chow tests

The paper demonstrates through a number of Monte Carlo experiments that, for the type of cross-section data sets typically encountered in applied economics, Chow tests on sorted variations of the data matrix can detect neglected parameter heterogeneity. The paper focuses on heterogeneity in the behavioural responses of economic actors that belong to different economically meaningful groups, such as the young, middle-aged, and old. Since the suggested methodology is easy to implement yet powerful, its routine use by applied economists would be desirable given the very significant estimation bias that can result from neglecting parameter heterogeneity.
First-principles Study of Back Contact Effects on CdTe Thin Film Solar Cells

Forming a chemically stable low-resistance back contact for CdTe thin film solar cells is critically important to the cell performance. This paper reports theoretical study of the effects of the back contact material, Sb2Te3, on the performance of the CdTe solar cells. First-principles calculations show that Sb impurities in p-type CdTe are donors and can diffuse with low diffusion barrier. There properties are clearly detrimental to the solar cell performance. The Sb segregation into the grain boundaries may be required to explain the good efficiencies for the CdTe solar cells with Sb2Te3 back contacts.
Modeling Work for Cognitive Work Support System Design in Operational Control Centers

The design of cognitive work support systems for operational control centers is an emerging challenge for human factors practitioners. This paper presents an example of applying techniques derived from the interactive design tradition to a context-of-use analysis, including both knowledge elicitation and modeling, to inform the design of a cognitive work support system. The paper integrates insights from the Cognitive Control Model—specifically, contextual control modes—into the cognitive analysis of work. The inclusion of COCOM in contextual inquiry helps to identify important contextual factors and brings meaning and organization to the different patterns of activity observed. Specifically, the paper presents the results of a contextual inquiry for airline operation control centers in the form of work models that have been extended to account for contextual control modes.
Wiresweep Reduction via Direct Cavity Injection During Encapsulation of Stacked Chip-Scale Packages

As packaging continues to offer challenges with variable stacked die configurations of increasing complexity, traditional transfer mold encapsulation faces challenges in defining a robust process window. A major concern is the problem of "wiresweep," wherein deformation of the wirebond during the mold process can potentially cause shortcircuiting. Several prior studies have focused on qualifying the effects of various wirebond and mold process parameters on package wiresweep, but most of these studies are restricted to single (discrete) die packages. This paper attempts to fill this gap of knowledge by experimenting with a variety of test vehicles with different stacking configurations. Specifically, the effects of varying loop height, stack height, and mold compound type are quantified in terms of maximum wiresweep. We find that loop height can have a considerable effect on wiresweep, with the maximum wiresweep being reduced by half (from around 6% to less than 3%) simply by reducing the loop height. Additionally, the study finds that for a given mold process, higher die stacks tend to increase wiresweep, although a threshold stack height exists beyond which further stacking can reduce wiresweep. Lastly, the data suggest that the choice of mold compound can adversely impact wiresweep, especially for test vehicles with traditionally high wiresweep. Having identified these trends, semianalytical models from the literature are used to investigate the cause behind these observations. The analysis suggests that the mold front velocity has the major root impact on package wiresweep. To validate this hypothesis, the series of tests conducted earlier is repeated for a compression mold process, which provides greater control over the mold front velocity. As predicted by the model, significant reduction in wiresweep is achieved. Thus, the compression mold process seems to offer the opportunity for reducing wiresweep without any compromise in the complexity of the die stack.
Gas-Grain Models for Interstellar Anion Chemistry

Long-chain hydrocarbon anions C(sub n) H(-) (n = 4, 6, 8) have recently been found to be abundant in a variety of interstellar clouds. In order to explain their large abundances in the denser (prestellar/protostellar) environments, new chemical models are constructed that include gas-grain interactions. Models including accretion of gas-phase species onto dust grains and cosmic-ray-induced desorption of atoms are able to reproduce the observed anion-to-neutral ratios, as well as the absolute abundances of anionic and neutral carbon chains, with a reasonable degree of accuracy. Due to their destructive effects, the depletion of oxygen atoms onto dust results in substantially greater polyyne and anion abundances in high-density gas (with n(sub H2) approx > / cubic cm). The large abundances of carbon-chain-bearing species observed in the envelopes of protostars such as L1527 can thus be explained without the need for warm carbon-chain chemistry. The C6H(-) anion-to-neutral ratio is found to be most sensitive to the atomic O and H abundances and the electron density. Therefore, as a core evolves, falling atomic abundances and rising electron densities are found to result in increasing anion-to-neutral ratios. Inclusion of cosmic-ray desorption of atoms in high-density models delays freeze-out, which results in a more temporally stable anion-to-neutral ratio, in better agreement with observations. Our models include reactions between oxygen atoms and carbon-chain anions to produce carbon-chain-oxide species C6O, C7O, HC6O, and HC7O, the abundances of which depend on the assumed branching ratios for associative electron detachment
A glimpse of Cre-mediated controversies in epicardial signalling.

Among the many important aspects of cardiac development, formation of the epicardium and the underlining signalling pathways that direct the mobilization and differentiation of epicardial cells have been one of the highly pursued research subjects within the past decade. These epicardium-derived cells (EPDCs) are reported to contribute to several critical cell types which include cardiac myofibroblasts and coronary smooth muscle contributing to the formation of the coronary vasculature network within the developing embryonic heart.1 Recent data suggesting that epicardial progenitor cells (EPCs) can contribute to newly formed cardiomyocytes in injured hearts2,3 has drawn further attention into the mechanisms of epicardiogenesis, as the successful use of epicardial cells in cell replacement therapies will undoubtedly have a high clinical impact on treating heart disease. To achieve this goal, a better understanding of the molecular mechanism that drive epicardiogenesis will be required. As the outermost cell layer of the vertebrate heart, the epicardium is derived from the proepicardial organ (PE), which originates from splanchnic mesenchyme within the septum transversum that is juxtaposed near the venous pole of the embryonic day 9.5 (E9.5) mouse heart (E22 for human). EPCs detach from the PE, migrate into pericardial cavity, and adhere to the myocardial surface where they rapidly spread to form a mesothelial monolayer covering the atria, atrioventricular canal, and ventricles, and in doing so, establish a primary epicardium by E10.5 in the mouse. Two days later, at E12.5, some of the primary epicardial cells undergo an epithelial to mesenchymal transition to convert into highly mobile and developmentally plastic EPDCs ( Figure 1 ). These EPDCs proceed to invade the subepicardial matrix and subsequently migrate into the myocardium, where they differentiate into interstitial …
Residence time control of systems subject to measurement noise

Abstract The residence time control problem is considered for linear systems that are subject to both input and measurement noise disturbances. It is shown that the maximal residence time is bounded and an upper bound is derived. Necessary and sufficient conditions for the existence of controllers that achieve the upper bound are derived and design techniques for residence time controllers are considered. Connections with optimal output feedback control are explored. The approach is based on an asymptotic version of the large deviations theory.
My sister's keeper?: genomic research and the identifiability of siblings

Genomic sequencing of SNPs is increasingly prevalent, though the amount of familial information these data contain has not been quantified. We provide a framework for measuring the risk to siblings of a patient's SNP genotype disclosure, and demonstrate that sibling SNP genotypes can be inferred with substantial accuracy. Extending this inference technique, we determine that a very low number of matches at commonly varying SNPs is sufficient to confirm sib-ship, demonstrating that published sequence data can reliably be used to derive sibling identities. Using HapMap trio data, at SNPs where one child is homozygotic major, with a minor allele frequency ≤ 0.20, (N = 452684, 65.1%) we achieve 91.9% inference accuracy for sibling genotypes. These findings demonstrate that substantial discrimination and privacy risks arise from use of inferred familial genomic data.
The New Face of Rhodium Alloys: Revealing Ordered Structures from First Principles

The experimental and computational data on rhodium binary alloys is sparse despite its importance in numerous applications, especially as an alloying agent in catalytic materials. Half of the Rh-transition metal systems (14 out of 28) are reported to be phase separating or are lacking experimental data. Comprehensive high-throughput first-principles calculations predict stable ordered structures in 9 of those 14 binary systems. They also predict a few unreported compounds in the known compound-forming systems. These results indicate the need for an extensive revision of our current understanding of Rh alloys through a combination of theoretical predictions and experimental validations.
Quantum corrections from nonresonant WW scattering

Abstract An estimate is presented of the leading radiative corrections to low energy electroweak precision measurements from strong nonresonant WW scattering at the TeV energy scale. The estimate is based on a novel representation of nonresonant scattering in terms of the exchange of an effective scalar propagator with simple poles in the complex energy plane. The resulting corrections have the form of the corrections from the standard model Higgs boson with the mass set to the unitarity scale for strong WW scattering.
Massless composite fermions in two-dimensions and the overlap

Abstract There exist chiral gauge models in two dimensions that have massless composite fermions. Two examples are presented and it is suggested that they be accepted as benchmark test-cases for generic proposals of non-perturbatively regulating chiral gauge theories in any dimension. We apply the overlap to the simpler of the two benchmarks and present the results of a numerical simulation of modest size.
Heavy Ion Induced Upsets in Semiconductor Devices

Heavy ions produced at various accelerator facilities have been employed to measure the effect of cosmic rays on semiconductor devices in space. An ion transmission counter, a solid state detector, and a position sensitive detector comprise the beam-monitor system used to measure the flux in real time and to monitor the spatial beam uniformity. An LSI 11/23 computer exercises the semiconductor devices under test. The technique of the experiment especially involving ever increasing complexity of devices will be described along with the upset results obtained from some devices.
The orientation of satellite galaxies : Evidence of elongation in the direction of the host

We use the fourth data release of the Sloan Digital Sky Survey to investigate the orientations of 4289 satellite galaxies with respect to their hosts. The orientation of the satellites is inconsistent with a random distribution at the 99.94% confidence level, and the satellites show a preference for elongation in the direction of their hosts. Further, on scales <50 kpc the major axes of the host galaxies and their satellites are preferentially aligned. Phrased in the terminology of weak lensing, the images of the satellites have a mean shear of γT = -0.045 ± 0.010, averaged over scales 10 kpc ≤ rP ≤ 50 kpc. In a galaxy-galaxy lensing study in which lenses and sources are separated solely on the basis of apparent magnitude, we estimate that on scales 250 kpc satellite galaxies account for between 10% and 15% of the objects that are identified as sources. In such studies, elongation of the satellites will cause a reduction of the galaxy-galaxy lensing shear by of order 25%-40%. Hence, the elongation of satellite galaxies in the direction of their hosts is a potentially important effect for precision studies of galaxy-galaxy lensing and argues strongly in favor of the use of accurate photometric redshifts in order to identify lenses and sources in future studies.
Magic, sorcery, and football among urban Zulu: a case of reinterpretation under acculturation

In discussing beliefs in witchcraft in Africa, Gluckman (2) points out that native beliefs in witchcraft not only persist in the face of continuing acculturation but often expand and change to meet the exigencies of new life situations. In fact, the impact of science, and particularly the impact of modem medicine, on previously nonliterate Africans actually inhibits their traditional beliefs and practices much less than might be expected; and although it would be incorrect to assert that Africans have rejected moder medicine-rejected, say modem germ theories of disease-the fact remains that they sustain the basic structure of their traditional
Lymphatics of the heart.

The anatomy of the cardiac lymphatic system of pigs, dogs, and humans has been studied by topical application of hydrogen peroxide and also by injection technics. In general, all three species have extensive subepicardial and subendocardial networks with collecting channels directed toward large ducts in the AV sulcus continuous with the main cardiac lymph duct. The subepicardial and subendocardial systems in dogs and pigs communicate via transmyocardial channels and channels in the supporting structures of the AV valves; in humans these communications have not been identified with certainty. Lymphatics are seen in both AV valves of dogs and pigs but have been seen only in the mitral valves of humans. The possible significance of these observations has been discussed.
The Timing of Bid Placement and Extent of Multiple Bidding: An Empirical Investigation Using eBay Online Auctions

Online auctions are fast gaining popularity in today’s electronic commerce. Relative to offline auctions, there is a greater degree of multiple bidding and late bidding in online auctions, an empirical finding by some recent research. These two behaviors (multiple bidding and late bidding) are of “strategic” importance to online auctions and hence important to investigate. In this article we empirically measure the distribution of bid timings and the extent of multiple bidding in a large set of online auctions, using bidder experience as a mediating variable. We use data from the popular auction site www.eBay.com to investigate more than 10,000 auctions from 15 consumer product categories. We estimate the distribution of late bidding and multiple bidding, which allows us to place these product categories along a continuum of these metrics (the extent of late bidding and the extent of multiple bidding). Interestingly, the results of the analysis distinguish most of the product categories from one another with respect to these metrics, implying that product categories, after controlling for bidder experience, differ in the extent of multiple bidding and late bidding observed in them. We also find a nonmonotonic impact of bidder experience on the timing of bid placements. Experienced bidders are “more” active either toward the close of auction or toward the start of auction. The impact of experience on the extent of multiple bidding, though, is monotonic across the auction interval; more experienced bidders tend to indulge “less” in multiple bidding.
Long-term outcomes of radiotherapy for stage II testicular seminoma--the Mayo Clinic experience.

Abstract Objectives To report long-term outcomes of patients with stage II testicular seminoma treated with radiotherapy (RT). Materials and methods A retrospective review was performed of 52 patients who received megavoltage RT for stage II testicular seminoma at Mayo Clinic between 1974 and 2007. Forty-eight patients (92%) had computed tomography staging. Overall survival (OS), relapse-free survival (RFS), and cause-specific survival (CSS) were determined using the Kaplan-Meier method. Major cardiac event (MCE) was defined as myocardial infarction, coronary artery bypass grafting or stenting, or valve replacement. Second malignancy (SM) was defined as biopsy-confirmed malignancy occurring in the RT field. Results The median patient age at diagnosis was 36 years. Stage was IIA ( n = 24), IIB ( n = 7), IIC ( n = 17), and II not otherwise specified (NOS, n = 4). The median infradiaphragmatic RT dose was 30.7 Gy. Twenty-six patients (50%) received prophylactic mediastinal/supraclavicular (MSCV) RT. The median follow-up was 19 years. Estimates of OS, RFS, and CSS were 94%, 80%, and 96% at 10 years, and 83%, 72%, and 96% at 20 years, respectively. RFS at 10 years for stage IIA, IIB, IIC, and II NOS were 83%, 54%, 81%, and 100%, respectively (log-rank P = 0.21). Ten patients (19%) experienced disease relapse in the MSCV region ( n = 7), para-aortic lymph nodes ( n = 1), lung ( n = 1), or peritoneal cavity ( n = 1). Eight patients were successfully salvaged with chemotherapy and/or surgery, while 2 died of seminoma. Risk of MSCV relapse was significantly lower in patients who received MSCV RT vs. those who did not (10-year estimates: 4% vs. 21%, respectively, log-rank P = 0.01). MCE occurred in 10 patients (19%) at a median of 18 years (range 7–30) after RT. SM occurred in 5 patients (10%) at a median of 27 years (range 20–34) after RT. Conclusions In patients with stage II testicular seminoma treated with RT, relapse in the irradiated site was uncommon. Infradiaphragmatic RT alone was associated with a significant risk of MSCV failure. Most MCE and SM events occurred more than 20 years after RT, highlighting the importance of vigilant long-term follow-up.
Higher-order time integration of Coulomb collisions in a plasma using Langevin equations

The extension of Langevin-equation Monte-Carlo algorithms for Coulomb collisions from the conventional Euler-Maruyama time integration to the next higher order of accuracy, the Milstein scheme, has been developed, implemented, and tested. This extension proceeds via a formulation of the angular scattering directly as stochastic differential equations in the fixed-frame spherical-coordinate velocity variables. Results from the numerical implementation show the expected improvement [O(@Dt) vs. O(@Dt^1^/^2)] in the strong convergence rate both for the speed |v| and angular components of the scattering. An important result is that this improved convergence is achieved for the angular component of the scattering if and only if the ''area-integral'' terms in the Milstein scheme are included. The resulting Milstein scheme is of value as a step towards algorithms with both improved accuracy and efficiency. These include both algorithms with improved convergence in the averages (weak convergence) and multi-time-level schemes. The latter have been shown to give a greatly reduced cost for a given overall error level when compared with conventional Monte-Carlo schemes, and their performance is improved considerably when the Milstein algorithm is used for the underlying time advance versus the Euler-Maruyama algorithm. A new method for sampling the area integrals is given which is a simplification of an earlier direct method and which retains high accuracy. This method, while being useful in its own right because of its relative simplicity, is also expected to considerably reduce the computational requirements for the direct conditional sampling of the area integrals that is needed for adaptive strong integration.
Halenaquinone and xestoquinone derivatives, inhibitors of Cdc25B phosphatase from a Xestospongia sp.

Abstract Separation of an extract of a Xestospongia sp., guided by bioassay against Cdc25B, led to the isolation of nine compounds, halenaquinone ( 1 ), xestoquinone ( 2 ), adociaquinones A ( 3 ) and B ( 4 ), 3-ketoadociaquinones A ( 5 ) and B ( 6 ), tetrahydrohalenaquinones A ( 7 ) and B ( 8 ), and 13- O -methyl xestoquinol sulfate ( 9 ). The structures of the new natural products 6 and 9 were established on the basis of extensive one- and two-dimensional NMR studies. Compounds 1 , 4 , and 6 inhibited recombinant human Cdc25B in vitro with IC 50 values of 0.7, 0.07, and 0.2 μM, respectively, and were 19- to 150-fold less active against two related protein phosphatases. Compound 4 blocked cell cycle progression through mitosis.
HEAVY-ELEMENT ENRICHMENT OF A JUPITER-MASS PROTOPLANET AS A FUNCTION OF ORBITAL LOCATION

One possible mechanism for giant planet formation is disk instability in which the planet is formed as a result of gravitational instability in the protoplanetary disk surrounding the young star. The final composition and core mass of the planet will depend on the planet's mass, environment, and the planetesimal accretion efficiency. We calculate heavy-element enrichment in a Jupiter-mass protoplanet formed by disk instability at various radial distances from the star, considering different disk masses and surface density distributions. Although the available mass for accretion increases with radial distance (a) for disk solid surface density (σ) functions σ = σ0 a –α with α< 2, the accretion timescale is significantly longer at larger radial distances. Efficient accretion is limited to the first ~105 years of planetary evolution, when the planet is extended and before gap opening and type II migration take place. The accreted mass is calculated for disk masses of 0.01, 0.05, and 0.1 M ☉ with α = 1/2, 1, and 3/2. We show that a Jupiter-mass protoplanet can accrete 1-110 M ⊕ of heavy elements, depending on the disk properties. Due to the limitation on the accretion timescale, our results provide lower bounds on heavy-element enrichment. Our results can explain the large variation in heavy-element enrichment found in extrasolar giant planets. Since higher disk surface density is found to lead to larger heavy-element enrichment, our model results are consistent with the correlation between heavy-element enrichment and stellar metallicity. Our calculations also suggest that Jupiter could have formed at a larger radial distance than its current location while still accreting the mass of heavy elements predicted by interior models. We conclude that in the disk instability model the final composition of a giant planet is strongly determined by its formation environment. The heavy-element abundance of a giant planet does not discriminate between its origin by either disk instability or core accretion.
Turbulence modeling in a hypersonic inlet

A study is conducted to analyze the performance of different turbulence models when applied to flow through a Mach 7.4 hypersonic inlet. The analysis, which is two-dimensional, is done by comparing computational results from a Parabolized Navier-Stokes code and a full Navier-Stokes code with experimantal data. The McDonaldCamarate (MC) and Baldwin-Lomax (BL) models were the two zero-equation models used in the study. The Turbulent Kinetic Energy (TKE) model was chosen as a representative higher-order model. The MC model, when run with user-specified transition of the boundary layer, provides a solution that compares excellently with the data. The BL model predicts separation of flow in the inlet, which contradicts experimental findings. The TKE model does not perform any better than the MC and BL models, despite the fact that it is a higher-order turbulence model.
Nuclear correlations in the 13C(π+, π0)13N reaction

Abstract Pauli and short range correlations are studied and shown to be important in the 13 C (π + , π 0 ) 13 N reaction near the resonance, helping to reduce appreciably the discrepancies between the experiment and previous theoretical results.
0.1 eV HgCdTe photoconductive detector performance

Abstract Progress in the development of 0.1 eV HgCdTe photoconductive detectors has resulted in D ∗ and responsivity performance approaching the theoretical thermal limit predicted by Auger recombination theory over a wide temperature range, together with significant improvements in l/f noise, array uniformity and bake stability. Simple Auger theory also accounts for the measured variation of ɡ- r noise with temperature above 70°K.
Geometric applications of a matrix-searching algorithm

LetA be a matrix with real entries and letj(i) be the index of the leftmost column containing the maximum value in rowi ofA.A is said to bemonotone ifi 1 >i 2 implies thatj(i 1) ≥J(i 2).A istotally monotone if all of its submatrices are monotone. We show that finding the maximum entry in each row of an arbitraryn xm monotone matrix requires Θ(m logn) time, whereas if the matrix is totally monotone the time is Θ(m) whenm≥n and is Θ(m(1 + log(n/m))) whenm<n. The problem of finding the maximum value within each row of a totally monotone matrix arises in several geometric algorithms such as the all-farthest-neighbors problem for the vertices of a convex polygon. Previously only the property of monotonicity, not total monotonicity, had been used within these algorithms. We use the Θ(m) bound on finding the maxima of wide totally monotone matrices to speed up these algorithms by a factor of logn.
Distributed channel quantization for two-user interference networks

We introduce conferencing-based distributed channel quantizers for two-user interference networks where interference signals are treated as noise. Compared with the conventional distributed quantizers where each receiver quantizes its own channel independently, the proposed quantizers allow multiple rounds of feedback communication in the form of conferencing between receivers. We take the network outage probabilities of sum rate and minimum rate as performance measures and consider quantizer design in the transmission strategies of time sharing and interference transmission. First, we propose distributed quantizers that achieve the optimal network outage probability of sum rate for both time sharing and interference transmission strategies with an average feedback rate of only two bits per channel state. Then, for the time sharing strategy, we propose a distributed quantizer that achieves the optimal network outage probability of minimum rate with finite average feedback rate; conventional quantizers require infinite rate to achieve the same performance. For the interference transmission strategy, a distributed quantizer that can approach the optimal network outage probability of minimum rate closely is also proposed. Numerical simulations confirm that our distributed quantizers based on conferencing outperform the conventional ones.
Nonlinear Response of Gas-Lubricated Shrouded Rayleigh-Step Thrust Pad

Quasi-static pressure characteristics of gas lubricated thrust bearing with shrouded Rayleigh step pads, solving nonlinear equation of motion
Safety and efficacy of digital rectal examination in patients with acute myocardial infarction

Safety and efficacy of digital rectal examination in patients with acute myocardial infarction
The cost of computer privacy

A little over one year ago, Honeywell Information Systems accepted an invitation to sponsor an important research project at Harvard University dealing with the subject of computer privacy. This work which was completed recently was performed by Dr. Robert C. Goldstein as partial fulfillment of his Doctoral Degree at Harvard.
Upsilon decay to a pair of bottom squarks

Abstract We calculate the rate for ϒ decay into a pair of bottom squarks as a function of the masses of the bottom squark and the gluino. Data from decays of the ϒ states could provide significant new bounds on the existence and masses of these supersymmetric particles.
Information-theoretic stochastic optimal control via incremental sampling-based algorithms

This paper considers optimal control of dynamical systems which are represented by nonlinear stochastic differential equations. It is well-known that the optimal control policy for this problem can be obtained as a function of a value function that satisfies a nonlinear partial differential equation, namely, the Hamilton-Jacobi-Bellman equation. This nonlinear PDE must be solved backwards in time, and this computation is intractable for large scale systems. Under certain assumptions, and after applying a logarithmic transformation, an alternative characterization of the optimal policy can be given in terms of a path integral. Path Integral (PI) based control methods have recently been shown to provide elegant solutions to a broad class of stochastic optimal control problems. One of the implementation challenges with this formalism is the computation of the expectation of a cost functional over the trajectories of the unforced dynamics. Computing such expectation over trajectories that are sampled uniformly may induce numerical instabilities due to the exponentiation of the cost. Therefore, sampling of low-cost trajectories is essential for the practical implementation of PI-based methods. In this paper, we use incremental sampling-based algorithms to sample useful trajectories from the unforced system dynamics, and make a novel connection between Rapidly-exploring Random Trees (RRTs) and information-theoretic stochastic optimal control. We show the results from the numerical implementation of the proposed approach to several examples.
Intelligent Packet Dropping for Optimal Energy-Delay Tradeoffs in Wireless Downlinks

We explore the advantages of intelligently dropping a small fraction of packets that arrive for transmission over a time varying wireless downlink. Without packet dropping, the optimal energy-delay tradeoff conforms to a square root tradeoff law, as shown by Berry and Gallager (2002). We show that intelligently dropping any non-zero fraction of the input rate dramatically changes this relation from a square root tradeoff law to a logarithmic tradeoff law. Further, we demonstrate an innovative algorithm for achieving this logarithmic tradeoff without requiring a-priori knowledge of arrival rates or channel probabilities. The algorithm can be implemented in real time and easily extends to yield similar performance for multi-user systems.
Non-perturbative superpotentials in string theory

Abstract The non-perturbative superpotential can be effectively calculated in M-theory compactification to three dimensions on a Calabi-Yau four-fold X. For certain X, the superpotential is identically zero, while for other X, a non-perturbative superpotential is generated. Using F-theory, these results carry over to certain Type IIB and heterotic string compactifications to four dimensions with N = 1 supersymmetry. In the heterotic string case, the non-perturbative superpotential can be interpreted as coming from space-time and world-sheet instantons; in many simple cases contributions come only from finitely many values of the instanton numbers.
On the Union of Cylinders in Three Dimensions

We show that the combinatorial complexity of the union of n infinite cylinders in ℝ3, having arbitrary radii, is O(n 2+e ), for any e>0; the bound is almost tight in the worst case, thus settling a conjecture of Agarwal and Sharir (Discrete Comput. Geom. 24:645–685, 2000), who established a nearly-quadratic bound for the restricted case of nearly congruent cylinders. Our result extends, in a significant way, the result of Agarwal and Sharir (Discrete Comput. Geom. 24:645–685, 2000), in particular, a simple specialization of our analysis to the case of nearly congruent cylinders yields a nearly-quadratic bound on the complexity of the union in that case, thus significantly simplifying the analysis in Agarwal and Sharir (Discrete Comput. Geom. 24:645–685, 2000). Finally, we extend our technique to the case of “cigars” of arbitrary radii (that is, Minkowski sums of line-segments and balls) and show that the combinatorial complexity of the union in this case is nearly-quadratic as well. This problem has been studied in Agarwal and Sharir (Discrete Comput. Geom. 24:645–685, 2000) for the restricted case where all cigars have (nearly) equal radii. Based on our new approach, the proof follows almost verbatim from the analysis for infinite cylinders and is significantly simpler than the proof presented in Agarwal and Sharir (Discrete Comput. Geom. 24:645–685, 2000).
Constructing Usable Documentation: A Study of Communicative Practices and the Early Uses of Mainframe Computing in Industry.

This study suggests that documentation is a complex technical communication genre, encompassing all the texts that mediate between complex human activities and computer processes. Drawing on a historical study, it demonstrates that the varied forms given to documentation have a long history, extending back at least to the early days of commercial mainframe computing. The data suggest that (1) early forms of documentation were borrowed from existing genres, and (2) official and unofficial documentation existed concurrently, despite efforts to consolidate these divergent texts. The study thus provides a glimpse into the early experimental nature of documentation as writers struggled to find a meaningful way to communicate information about their organization's developing computer technology.
Black holes at future colliders and in cosmic rays

One of the most dramatic consequences of low-scale (~ 1 TeV) quantum gravity would be copious production of mini black holes at future accelerators and in ultra-high-energy cosmic ray interactions. Hawking radiation of these black holes is constrained mainly to our (3+1)-dimensional world and results in their rapid evaporation. We review selected topics in the mini-black-hole phenomenology, such as production rates at colliders and in cosmic rays, Hawking radiation as a sensitive probe of the dimensionality of extra space, as well as an exciting possibility of finding new physics in the decays of black holes. PACS: 04.70.-s Physics of black holes – 04.50.+h Gravity in more than four dimensions – 11.25.Wx String and brane phenomenology – 14.80.-j Other particles
Intonation contour and syntactic structure as predictors of apparent segmentation.

The relative contributions of intonation and syntax to the segmentation or “chunking” of speech stimuli was examined using the “click migration” technique. In the first experiment normal‐hearing subjects perceptually located clicks in syntactic and nonsyntactic stimuli in which intonation pattern was varied. The tendency for the perception of interrupting stimuli to cluster was significantly greater at boundaries that were marked by both syntactic and prosodic cues than at those marked by intonation alone. In the second experiment sentences in which intonation pattern was varied were presented on videotape to deaf and normal‐hearing lip readers. Subjects were required to locate a visual flash embedded in the spoken sentence without auditory cues to intonation pattern. The normal‐hearing subjects failed to show significant perceptual migration of interrupting flashes. Deaf subjects, however, showed significant perceptual migration toward the major syntactic boundary when it coincided with the intonation boundary. Deaf subjects' performance on the lip‐reading task strongly resembled that of normal subjects on the auditory task. [Work supported by NIH.]
Ground ring of two-dimensional string theory

Abstract String theories with two-dimensional space-time target spaces are characterized by the existence of a “ground ring” of operators of spin (0, 0). By understanding this ring, one can understand the symmetries of the theory and illuminate the relation of the critical string theory to matrix models. The symmetry groups that arise are, roughly, the area-preserving diffeomorphisms of a two-dimensional phase space that preserve the Fermi surface (of the matrix model) and the volume-preserving diffeomorphisms of a three-dimensional cone. The three dimensions in question are the matrix eigenvalue, its canonical momentum, and the time of the matrix model.
Optimal risk sharing through renegotiation of simple contracts

Abstract We frequently observe that contracts do not include all of the contingencies that would seem to be necessary for optimal risk sharing between the parties to the contract. One reason may be that the possibility of renegotiation makes the contract more contingent than it appears. A simple contracting problem is used to show how even a simple contract may achieve optimal risk sharing if new information arrives slowly relatively to the speed of renegotiation.
A facile synthesis of cyanoguanidines from thioureas

Abstract A facile synthesis of cyanoguanidines from corresponding thioureas is reported using 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (water soluble carbodiimide).
Unsteady Separation over Maneuvering Bodies

Abstract : Development of a new boundary layer code has reached the status to permit meaningful applications. Computations have been carried out for the initiation of separation in the symmetry plane of a prolate spheroid of slenderness ratio 1/4, impulsively started into forward motion at zero incidence and also at 50 degrees angle. This case serves as validation by comparing with previously published results of Xu and Wang (ref.1), and also demonstrates that our method gives information of flow near the rear stagnation point not available in the literature. More studies have been performed on the optimization of surface suction to delay or prevent the unsteady separation for an impulsively started circular cylinder. Here the methodology should be of interest. Work on an unsteady three-dimensional thin-layer Navier-Stokes code, however, is progressing slowly. Keywords: Unsteady separation, three dimensional moving body, Separation control.
Restructurable control using proportional-integral implicit model following

Studies of a proportional-integral implicit modelfollowing control law are presented. The research focuses on the ability of the control law to recover the performance of a failed system to its pre-failure level. Properties of the implicit model-following strategy are examined, and conditions for control reconfiguration are stated. The control law is applied to the lateral-directional model of a fighter aircraft, and control restructuring is shown for changes in control and system matrices. It is concluded that the implicit-model following scheme is a good candidate for control reconfiguration.