cssi/SciSciGPT-SciSciNet huggingface dataset:
Coulomb enhancement of the third-order nonlinearities in the mesoscopic semiconductor structures

The prospects for the enhancement of the third-order optical nonlinearity in the mesoscopic semiconductor structures: quantum wells, wires, and boxes are analyzed. It is shown, that if the structures are designed in such a way that the ground state and the excited states wavefunctions are spatially separated, then the electrostatic Coulomb interactions will result in the enhancement of the optical nonlinearity. The enhancement factor has been analyzed for the structures of different shapes and material compositions. It was found that the possible enhancement factor ranges from 2 for quantum wells to 10 for quantum wires and boxes.
Construction of exact multimonopole solutions

The newly found exact axially symmetric multimonopole solutions of arbitrary topological charge are constructed and proven to be real. Arguments supporting the regularity of the solutions are presented.
Emulator-assisted reduced-rank ecological data assimilation for nonlinear multivariate dynamical spatio-temporal processes

Abstract As ecological data sets increase in spatial and temporal extent with the advent of new remote sensing platforms and long-term monitoring networks, there is increasing interest in forecasting ecological processes. Such forecasts require realistic initial conditions over complete spatial domains. Typically, data sources are incomplete in space, and the processes include complicated dynamical interactions across physical and biological variables. This suggests that data assimilation, whereby observations are fused with mechanistic models, is the most appropriate means of generating complete initial conditions. Often, the mechanistic models used for these procedures are very expensive computationally. We demonstrate a rank-reduced approach for ecological data assimilation whereby the mechanistic model is based on a statistical emulator. Critically, the rank-reduction and emulator construction are linked and, by utilizing a hierarchical framework, uncertainty associated with the dynamical emulator can be accounted for. This provides a so-called “weak-constraint” data assimilation procedure. This approach is demonstrated on a high-dimensional multivariate coupled biogeochemical ocean process.
The use of CBr4 and SiBr4 doping in MOMBE and application to InP-based heterojunction bipolar transistor structures

Abstract The use of silicon tetrabromide and carbon tetrabromide for n- and p-type doping respectively of In 0.53 Ga 0.47 As and InP materials grown by metalorganic molecular beam epitaxy (MOMBE) has been investigated. Controllable n-type doping concentrations from 1 × 10 16 cm −3 to 6 × 10 19 cm −3 have been obtained in InP using SiBr 4 and tertiarybutylphosphine (TBP). Silicon doping concentrations from n = 1 × 10 16 cm −3 to 1 × 10 19 cm −3 have been obtained in InGaAs grown using tertiarybutylarsine (TBA). Slightly lower concentrations were obtained when using tris-dimethylaminoarsenic (DMAAs) as the arsenic source. A memory effect has been observed when transitioning from heavily to lightly doped layers, and is attributed to accumulated SiBr 4 evaporating from uncooled surfaces in the growth chamber. Carbon doping of InGaAs to carrier concentrations of 8 × 10 19 cm −3 have been obtained with CBr 4 and TBA; however, significantly lower p-type doping levels are obtained when DMAAs is used as the arsenic source. We attribute this behavior to the DMAAs decomposition products reacting with carbon on the wafer surface. Secondary ion mass spectroscopy (SIMS) profiling of heavily Si- and C-doped materials indicates that bromine incorporation is below the detection level of our instrument ( 15 cm −3 ). These dopant sources have been used for the growth of InP-based heterojunction bipolar transistor (HBT) structures. Both single- and double-heterojunction device structures have been produced with f t of 69–91 GHz and f max of 163–166 GHz, which are comparable to the same structures grown using conventional dopant sources.
Excitation cross sections for electron scattering from K + ions

The $B$-spline Breit-Pauli $R$-matrix method is used to investigate electron scattering from singly ionized potassium in the energy range from threshold to $400\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$. The primary aim of the present work is to resolve discrepancies between the available experimental and theoretical cross sections for excitation of the ${\mathrm{K}}^{+}$ resonance lines. The multiconfiguration Hartree-Fock method with term-dependent nonorthogonal orbitals is employed for an accurate representation of the target wavefunctions. The close-coupling expansion includes 43 bound levels of ${\mathrm{K}}^{+}$ covering all possible terms of the lowest configurations $3{p}^{6}$, $3{p}^{5}4s$, $3{p}^{5}3d$, $3{p}^{5}4p$, $3{p}^{5}5s$, and $3{p}^{5}4d$. Our results confirm that the apparent cross section for the $(60.1+60.8+61.3)\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ emission line from the $3{p}^{5}(4s+3d)$ levels in the crossed-beams experiment of Zapesochny et al. {Zh. Eksp. Teor. Fiz. 90, 1972 (1986) [Sov. Phys. JETP 63, 1155 (1986)]} was normalized with an error of about a factor of 4. We also present the cross sections for excitation of the $3{p}^{5}4p$, $3{p}^{5}5s$, and $3{p}^{5}4d$ levels and discuss the cascade contribution from higher excited levels to the $3{p}^{5}4s$ and $3{p}^{5}3d$ levels.
Extracting the pore size distribution of compliant materials from nitrogen adsorption

Abstract Adsorption of nitrogen at 77.4 K is a well-established technique for the characterization of mesopores. However, this method has been questioned in the case of compliant materials, as the capillary pressures upon sorption can be as large as several MPa's and thus high deformations are expected upon analysis. Simultaneous recording of nitrogen sorption data and linear length changes for silica aerogels, a class of highly porous, compliant materials, reveals a new type of isotherm, that is characteristic for compliant materials in general. Comparison of dilatation and sorption data shows that the bulk modulus of a compliant material can be calculated from its nitrogen sorption isotherm alone. Using this information together with a model that describes the relationship between macroscopic deformation and changes in pore size and volume, the isotherm can be corrected for the contraction of the sample during analysis. The corresponding pore size distribution is found to be in excellent agreement with results deduced from small angle X-ray scattering.
Turbulent Flow Heat Transfer and Friction in a Rectangular Channel With Varying Number of Ribbed Walls

An experimental study of wall heat transfer and friction characteristics of a fully developed turbulent air flow in a rectangular channel with transverse ribs on one, two, and four walls is reported. Tests were performed for Reynolds numbers ranging from 10,000 to 80,000. The pitch-to-rib height ratio, P/e, was kept at 8 and rib height-to-channel hydraulic diameter ratio, e/D h , was kept at 0.0625. The channel length-to-hydraulic diameter ratio, L/D h , was 15. The heat transfer coefficient and friction factor values were enhanced with the increase in the number of ribbed walls. The friction roughness function, R(e + ), was almost constant over the entire range of tests performed and was within comparable limits of the previously published data. The heat transfer roughness function, G(e + ), decreased with additional ribbed walls and compared well with previous work in this area. Friction data obtained experimentally for the case with four ribbed walls compared well with the values predicted by the assumed theoretical relationship used in the present study and past publications. Results of this investigation could be used in various applications of internal channel turbulent flows involving different numbers of roughened walls.
Human factors and education: evolution and contributions.

Objective: The major contributions of human factors to education are highlighted. Background: Over the past 50 years, the education of human factors specialists has evolved, as well as the application of human factors and ergonomic knowledge to education. Method: Human factors and ergonomics professional documentation and literature were reviewed to identify major events relevant to human factors education or the application of human factors to education. Results: Human factors education has evolved from training in experimental psychology to highly specialized accredited human factors programs and a number of undergraduate programs, leading to program accreditation and the certification of professionals. In addition, human factors specialists have applied their knowledge to human factors education and, more recently, to educational systems in general. The greatest focus has been on technology such as multimedia. Others have evaluated the design of the physical environment, focusing primarily on seating. ...
Mechanism of Transcriptional Repression of E2F by the Retinoblastoma Tumor Suppressor Protein

The retinoblastoma tumor suppressor protein (pRB) is a transcriptional repressor, critical for normal cell cycle progression. We have undertaken studies using a highly purified reconstituted in vitro transcription system to demonstrate how pRB can repress transcriptional activation mediated by the E2F transcription factor. Remarkably, E2F activation became resistant to pRB-mediated repression after the establishment of a partial (TFIIA/TFIID) preinitiation complex (PIC). DNase I footprinting studies suggest that E2F recruits TFIID to the promoter in a step that also requires TFIIA and confirm that recruitment of the PIC by E2F is blocked by pRB. These studies suggest a detailed mechanism by which E2F activates and pRB represses transcription without the requirement of histone-modifying enzymes.
Of Miracles and Interventions

In Making Things Happen, James Woodward influentially combines a causal modeling analysis of actual causation with an interventionist semantics for the counterfactuals encoded in causal models. This leads to circularities, since interventions are defined in terms of both actual causation and interventionist counterfactuals. Circularity can be avoided by instead combining a causal modeling analysis with a semantics along the lines of that given by David Lewis, on which counterfactuals are to be evaluated with respect to worlds in which their antecedents are realized by miracles. I argue, pace Woodward, that causal modeling analyses perform just as well when combined with the Lewisian semantics as when combined with the interventionist semantics. Reductivity therefore remains a reasonable hope.
Androgen receptors in ventral prostate glands of zinc deficient rats.

Abstract Androgen binding has been studied in the prostate cytosol of zinc deficient rats by charcoal assays. Rats were housed individually in plastic cages and maintained on a zinc deficient diet for 3 months. The cytosol fraction of prostate gland was incubated with various concentrations of tritiated methyltrienolone ( 3 H-R1881, a synthetic androgen) alone or in the presence of 500-fold excess of radioinert R1881. Scatchard analysis of the data revealed that the number of androgen binding sites in the cytosol fraction of the zinc deficient rat prostate was 31 ± 5.2 fmol/mg cytosol protein. This was significantly lower than that (84 ± 11.5 fmol/mg protein) of the controls. Their dissociation constant (Kd = 1.6 ± 0.6 nM) on the other hand was not different from that (1.7 ± 0.7 nM) of control animals. This decrease in the concentration of cytosol receptor sites in the zinc deficient state suggests that this metal is involved in the androgen-binding process in the target cells.
Collaborating to Improve Students’ Transitions From High School Mathematics to College: Characteristics and Outcomes of a Cross-Sector Professional Development Project

In this article, the authors discuss the characteristics and outcomes of a secondary-postsecondary collaborative professional development project. This project was initiated to address the issue of students’ difficulties transitioning from secondary mathematics to postsecondary courses. Key characteristics include a climate of mutual respect, the opportunity to share perspectives on instructional approaches and student work over an extended time, and commitment to identifying and trying “little changes” based on their context and beliefs.
Rachel’s literacy stories: unpacking one preservice teacher’s moral perspectives on literacy teaching

While teacher educators agree that teaching is a profoundly moral activity, little attention has been placed on the moral perspectives about teaching and learning of those entering the teaching workforce. As a way of illustrating the importance of helping both future teachers become aware of their own moral compasses and teacher educators to understand ways in which such knowledge can support their students, I use methods of qualitative inquiry to explore the life history of one European American preservice elementary teacher in the USA. In recounting the events of her life, Rachel Rosenberg demonstrates how she uses her own life experiences to frame the moral aspects of her future role as a teacher and especially her perspectives on literacy teaching and learning. The methods used here to elicit and analyse Rachel’s story can be useful to teacher educators who want to understand how the moral perspectives embedded in teachers’ stories influence the ways in which teachers approach and enact the work of te...
Textures for realistic image synthesis

Abstract An important aspect in generating images of real materials and surfaces is the contribution of the visual effects of textures. This study presents methods for simulating a variety of different textures. Two general types of texture, geometric and spectral, are simulated. Geometric textures incorporate the irregularities and variations which can be found in the shape and form of real surfaces. Spectral textures involve variations of the properties of materials which cause the absorption of specific wavelengths of light. An integrated system for image synthesis which is based on ray tracing is used as the testbed for the texturing research. Previous methods of texturing are adapted by ray tracing, and some new methods for simulating heterogeneous materials are presented.
Evaluation of satellite rainfall products through hydrologic simulation in a fully distributed hydrologic model

[1] The goal of this study is to evaluate the accuracy of four global high-resolution satellite rainfall products (CMORPH, TMPA 3B42RT, TMPA 3B42, and PERSIANN) through the hydrologic simulation of a 1656 km2 mountainous watershed in the fully distributed MIKE SHE hydrologic model. This study shows that there are significant biases in the satellite rainfall estimates and large variations in rainfall amounts, leading to large variations in hydrologic simulations. The rainfall algorithms that use primarily microwave data (CMORPH and TMPA 3B42RT) show consistent and better performance in streamflow simulation (bias in the order of −53% to −3%, Nash-Sutcliffe efficiency (NSE) from 0.34 to 0.65); the rainfall algorithm that uses primarily infrared data (PERSIANN) shows lower performance (bias from −82% to −3%, Nash-Sutcliffe efficiency from −0.39 to 0.43); and the rainfall algorithm that merges the satellite data with rain gage data (TMPA 3B42) shows inconsistencies and the lowest performance (bias from −86% to 0.43%, Nash-Sutcliffe efficiency from −0.50 to 0.27). A dilemma between calibrating the hydrologic model with rain gage data and calibrating it with the corresponding satellite rainfall data is presented. Calibrating the model with corresponding satellite rainfall data increases the performance of satellite streamflow simulation compared to the model calibrated with rain gage data, but decreases the performance of satellite evapotranspiration simulation.
Nearest-neighbor diffusion-based pan-sharpening algorithm for spectral images

Commercial multispectral satellite datasets, such as WorldView-2 and Geoeye-1 images, are often delivered with a high-spatial resolution panchromatic image (PAN) as well as a corresponding lower resolution multispectral image (MSI). Certain fine features are only visible on the PAN but are difficult to discern on the MSI. To fully utilize the high-spatial resolution of the PAN and the rich spectral information from the MSI, a pan-sharpening process can be carried out. However, difficulties arise in maintaining radiometric accuracy, particularly for applications other than visual assessment. We propose a fast pan-sharpening process based on nearest-neighbor diffusion with the aim to enhance the salient spatial features while preserving spectral fidelity. Our approach assumes that each pixel spectrum in the pan-sharpened image is a weighted linear mixture of the spectra of its immediate neighboring superpixels; it treats each spectrum as its smallest element of operation, which is different from the most existing algorithms that process each band separately. Our approach is shown to be capable of preserving salient spatial and spectral features. We expect this algorithm to facilitate fine feature extraction from satellite images.
Pituitary Responsiveness to LRF in Castrated Male Hamsters Exposed to Different Photoperiodic Conditions

The effect of various doses of LRF on pituitary LH and FSH release was examined in castrated adult male hamsters with different photoperiodic histories. Gonadotropin (Gn) release in response to LRF wa
Hyperfine magnetic fields in cubic uranium compounds from 238U Mössbauer spectroscopy

Abstract The hyperfine fields at the uranium nucleus in magnetically ordered US and UP were found to be (3300 ± 300) kOe and (3600 ± 300) kOe, respectively. Combining this with earlier data on UO2 and USb, and with known values of the magnetic moment on the uranium ion, it is found that J-mixing is not dominant in these cubic uranium compounds.
Production and purification of novel secreted human proteins

Abstract Our objective during the last year was to produce and purify 50–80 novel, secreted human proteins identified via high throughput cDNA sequencing and computer analysis. We chose the baculovirus expression vector system in order to obtain secreted, correctly folded, bioactive proteins. Recombinant (re-)baculoviruses (BV) were plaque purified, and pulse-labeling was used to verify the synthesis and secretion of the re-proteins. N-terminal microsequencing was performed to simultaneously confirm the identity of the protein(s) as well as the signal peptide (SP) cleavage site(s). Following sequence confirmation, the proteins were purified to homogeneity and functional assays carried out to determine potential therapeutic applications. We identified proteins with antiviral activity, several novel growth factors, proteins influencing the differentiation of specific cell types, novel proteases and protease inhibitors among others. Certain proteins were expressed both in insect cells and in CHO stable cell lines. In the cases analyzed, we found that the same SP cleavage site was utilized in the two expression systems. Significant differences were observed in the carbohydrate moieties attached to the proteins, though no effects on the biological activity due to these differences have been demonstrated. The BV system has served as a viable alternative for the high throughput, high fidelity expression of many novel secreted human genes. To date, more than 75 new genes have been expressed, and the re-proteins purified. This expression system combines many favorable traits including relative speed, moderate cost but perhaps most importantly, the production of biologically active proteins.
Differential-geometric model-based control (DGMBC): A software package for controller design

This paper presents a new software package, called differential-geometric model-based control (DGMBC), which carries out symbolic manipulations to automatically generate differential-geometric, model-based controllers and subsequently tests the designed controller. This prototype software was developed to simplify the industrial implementation and testing of differential-geometric, model-based controllers on lumped-parameter processes. DGMBC has a user-friendly interface that allows a user to enter process model equations and parameters easily. The user interface was developed using Visual Basic and linked to MATHEMATICA using MathLink. The user enters the process model (set of ordinary differential equations), and the software generates an analytical model-based controller, if an analytical solution exists. The resulting analytical model-based controller (set of ordinary differential and algebraic equations) can be in FORTRAN, C, or MATLAB format. DGMBC can also simulate the closed-loop process responses. The application and implementation of DGMBC 1.0 are shown using three chemical and biochemical process examples with varying levels of complexity. An analytical model-based controller is designed for each of the processes, and simulation results showing the closed-loop process responses are presented.
Jerry Morris: pathfinder for health through an active and fit way of life

We extend greetings and best wishes to Jeremy Noah Morris on the occasion of his 90th birthday celebration, 6 May 2000. Professor Morris, better known as Jerry, was born in Liverpool, educated in Glasgow and London, and today is Emeritus Professor of Public Health at the London School of Hygiene and Tropical Medicine. He is a renowned physician-epidemiologist who has made landmark scientific contributions to our understanding of physical exercise and dietary intake as they affect risk of developing coronary heart disease (CHD, or heart attack), and to our understanding of the role of social inequalities in risk of disease. As a protagonist, he has worked tirelessly to develop public policies to prevent disease, promote good health, and overcome those social factors that predispose to disease and limit access to health care. Based on three long term studies over the last half century, one of London transport workers and two of executive grade British civil servants, Jerry Morris has demonstrated conclusively that a physically active …
Organization of the Human ζ-Crystallin/Quinone Reductase Gene (CRYZ)

zeta-Crystallin is a protein highly expressed in the lens of guinea pigs and camels, where it comprises about 10% of the total soluble protein. It has recently been characterized as a novel quinone oxidoreductase present in a variety of mammalian tissues. We report here the isolation and characterization of the human zeta-crystallin gene (CRYZ) and its processed pseudogene. The functional gene is composed of nine exons and spans about 20 kb. The 5'-flanking region of the gene is rich in G and C (58%) and lacks TATA and CAAT boxes. Previous analysis of the guinea pig gene revealed the presence of two different promoters, one responsible for the high lens-specific expression and the other for expression at the enzymatic level in numerous tissues. Comparative analysis with the guinea pig gene shows that a region of approximately 2.5 kb that includes the promoter responsible for the high expression in the lens in guinea pig is not present in the human gene.
Retinal receptors in rodents maximally sensitive to ultraviolet light

HIGH sensitivity to near-ultraviolet light is a fundamental feature of vision in many invertebrates1,2. Among vertebrates there are some amphibians, birds and fishes that are also sensitive to near-ultraviolet wavelengths3–6. This sensitivity can be achieved through a class of cone photoreceptor containing an ultraviolet-sensitive pigment7–9. Although these receptors were thought not to exist in the eyes of mammals, we now report that some rodents have a retinal mechanism that is maximally sensitive to ultraviolet light.
Buckling and postbuckling of magnetoelastic flat plates carrying an electric current

The basic equations of a fully nonlinear theory of electromagnetically conducting flat plates carrying an electric cur- rent and exposed to a magnetic field of arbitrary orientation are derived. The relevant equations have been obtained by considering that both the elastic and electromagnetic media are homogeneous and isotropic. The geometrical nonlin- earities are considered in the von-Karman sense, and the soft ferromagnetic material of the plate is assumed to feature negligible hysteretic losses. Based on the electromagnetic and elastokinetic field equations, by using the standard aver- aging methods, the 3-D coupled problem is reduced to an equivalent 2-D one, appropriate to the theory of plates. Having in view that the elastic structures carrying an electric current are prone to buckling, by using the presently devel- oped theory, the associated problems of buckling and postbuckling are investigated. In this context, the problem of the electrical current inducing the buckling instability of the plate, and its influence on the postbuckling behavior are analyzed. In the same context, the problem of the natural frequency-electrical current interaction of flat plates, as influ- enced by a magnetic field is also addressed. � 2005 Published by Elsevier Ltd.
Ice-Nucleating Active Bacteria Decrease the Cold-Hardiness of Stored Grain Insects

This report provides further evidence that a freeze-dried, concentrated form of Pseudomonas syringae , an ice-nucleating active bacteria, reduces the cold tolerance of stored grain insect pests. Application of ice-nucleating bacteria to wheat or corn that contained insect pests decreased the insects’ supercooling capacity: after treatment with 100 ppm of P. syringae the mean supercooling points of five insect species increased from 4.7 to 11.9°C above untreated controls. Treatment with P. syringae also decreased the capacity of insects to survive a 24-h exposure to subzero temperatures. Decreases in cold tolerance were observed in eight species of stored grain pests: Indianmeal moth larvae, Plodia interpullctella (Hubner); red flour beetle adults, Tribolium castaneum (Herbst); flat grain beetle adults, Cryptolestes pusillus (Schon herr); rusty grain beetle adults, Cryptolestes ferrugineus (Stephens); Gibbium psylloides (Czenpinski); lesser grain borer adults, Rhyzopertha dominica (F.); yellow meal worm larvae, Tenebrio molitor (L.); and granary weevil adults, Sitophilus granarius granarius (L.). Results of this study provide further support for the use of ice-nucleating active bacteria as biological insecticides to kill overwintering insects by decreasing their low temperature tolerance. The approach may be particularly appropriate for the control of a variety of insect pests in restricted areas such as grain bins.
Density matrix descriptions for electromagnetically induced transparency and related pump-probe optical phenomena in moving atomic systems

Reduced density matrix descriptions are developed for linear and non-linear electromagnetic interactions of moving atomic systems, taking into account applied magnetic fields as well as atomic collisions together with other environmental decoherence and relaxation processes. Applications of interest include electromagnetically induced transparency and related pump-probe optical phenomena in warm atomic vapors. Time-domain (equation-of-motion) and frequency-domain (resolvent-operator) formulations are developed in a unified manner. The standard Born (lowestorder perturbation-theory) and Markov (short-memory-time) approximations are systematically introduced within the framework of the general non-perturbative and non-Markovian formulations. A preliminary semiclassical treatment of the electromagnetic interaction is adopted. However, the need for a fully quantum mechanical approach is emphasized. Compact Liouville-space operator expressions are derived for the linear and the general (n'th order) non-linear macroscopic electromagnetic-response tensors occurring in a perturbation-theory treatment of the semiclassical electromagnetic interaction. These expressions can be evaluated for coherent initial atomic excitations and for the full tetradic-matrix form of the Liouville-space self-energy operator representing the environmental interactions in the Markov approximation. Collisional interactions between atoms can be treated in various approximations for the selfenergy operator, and the influence of Zeeman coherences on the macroscopic electromagnetic response can be investigated.
Coming to the Cultural “In-Between”: Nursing Insights From a Hmong Birth Case Study

This article discusses the historical background and traditional beliefs of the Hmong. Cultural conflict occurs when traditional Hmong beliefs and Western health care ideologies are misunderstood. A specific case study focuses on care of a Hmong woman and her husband after a precipitous birth, hemorrhage, and surgical intervention. Nursing insights are identified from "in-between" the cultures. Establishing cultural awareness is an essential first step toward cultural competence.
A CCSD(T) and ccCA study of mixed silicon hydrides and halides: Structures and thermochemistry

Abstract A set of 24 mixed silicon hydrides and halides (SiH n X m − n , where X = F, Cl; m = 1–4; and n = 0– m ) has been investigated using; (1) CCSD(T) with the correlation consistent basis sets of double-through quintuple-ζ quality; (2) CCSD(T) with the augmented tight d form of the correlation consistent basis sets for the second row atoms (Si and Cl); and (3) the recently developed correlation consistent composite approach (ccCA). Optimized geometries and harmonic vibrational frequencies are reported, as well as enthalpies of formation, free energies of formation, and dissociation reaction enthalpies. Relativistic effects, including atomic spin-orbit coupling and scalar relativistic effects, and core-valence correlation, have been accounted for via the ccCA formulism. As demonstrated in previous studies, the tight d basis sets accelerate the convergence, as compared to the standard correlation consistent basis sets, of CCSD(T)-computed geometries and energetics of molecular species containing second row, main group atoms. The ccCA enthalpies of formation are shown to be similar and, on average, better than the corresponding CCSD(T) enthalpies of formation for the silicon species. Further, large DKH-CCSD(T) computations with explicit inclusion of core-valence and scalar relativistic effects have been performed to predict the enthalpies of formation of SiHF, SiHCl, SiH 2 F, SiHF 2 , SiH 2 Cl, and SiHCl 2 .
Strategies for Avoiding Recommendations for Additional Imaging Through a Comprehensive Comparison With Prior Studies

Abstract Purpose To determine the frequency and characteristics of recommendations for additional imaging and/or intervention (RAIs) in abdominal CT and MRI interpretations that might be avoided through comprehensive comparison with all available prior examinations. Methods A total of 1,006 RAIs in abdominopelvic CT and MRI reports were retrospectively evaluated. Reports and images from each patient's prior imaging examinations, including those of all relevant body parts and modalities, were reviewed to determine if the RAI could have been avoided based on prior imaging. Frequency and characteristics of such "avoidable" RAIs were evaluated. Results A total of 41 of 1,006 (4.1%) RAIs were avoidable. The key prior examination that established the RAI as avoidable was a different modality in 53.7% (22 of 41) and on a different body area in 41.5% (17 of 41) of cases, including chest imaging in 31.7% (13 of 41). A total of 83.3% (5 of 6) adrenal RAIs, and 80.0% (4 of 5) liver RAIs were avoidable based on prior chest imaging. The key finding was present on the prior images but was not described in the report in 46.3% (19 of 41) of cases. A greater number of prior examinations were available in cases of avoidable RAIs (mean, 12.2 ± 16.7) than in those of nonavoidable RAIs (mean, 5.7 ± 9.5) ( P Conclusions A small fraction of RAIs can be avoided by performing a thorough evaluation of all prior imaging examinations, including different modalities and body parts. Nearly half of the key prior examinations did not report the finding, highlighting the importance of directly reviewing relevant images, particularly chest imaging for evaluation of indeterminate upper-abdominal findings. Configuration of PACS for optimized selection and display of relevant examination reports and images may facilitate such comparisons.
PARALLEL SUBSPACE PROJECTION BEAMFORMING FOR AUTONOMOUS, PASSIVE SONAR SIGNAL PROCESSING

Adaptive techniques can be applied to improve performance of a beamformer in a cluttered environment. The sequential implementation of an adaptive beamformer, for many sensors and over a wide band of frequencies, presents a serious computational challenge. By coupling each transducer node with a microprocessor, in-situ parallel processing applied to an adaptive beamformer on a distributed system can glean advantages in execution speed, fault tolerance, scalability, and cost. In this paper, parallel algorithms for Subspace Projection Beamforming (SPB), using QR decomposition on distributed systems, are introduced for in-situ signal processing. Performance results from parallel and sequential algorithms are presented using a distributed system testbed comprised of a cluster of computers connected by a network. The execution times, parallel efficiencies, and memory requirements of each parallel algorithm are presented and analyzed. The results of these analyses demonstrate that parallel in-situ processing holds the potential to meet the needs of future advanced beamforming algorithms in a scalable fashion.
Grinding and pozzolanic reactivity of quartz powders

Abstract Cement-based materials are in wide use — partly in the belief that their reactivity is due to their glassy nature. The question we wish to investigate is: how specific is the link between the pozzolanic reaction and glassy materials? In order to answer it, we take the case of quartz, a material often used in cement-based matrices, reputed to be chemically inert due to its crystalline structure. Our tests have shown the pozzolanic reaction of quartz to be a complex dissolution–precipitation reaction involving multiple parameters. One of these, we find, has particular importance: above a certain critical particle diameter, the reaction becomes barely perceptible.
Anisotropy of the Gray-Tin Γ 8 + Conduction Band

The angular dependences of the Shubnikov-de Haas periods and effective masses of the ${{\ensuremath{\Gamma}}_{8}}^{+}$ conductionband electrons in gray tin are analyzed in terms of a mathematical model similar to that of Dresselhaus, Kip, and Kittel for the ${{\ensuremath{\Gamma}}_{8}}^{+}$ valence bands of Ge. The observed 5% variations in periods and masses are accounted for by $〈111〉$ protrusions on a nearly spherical Fermi surface. The degree of nonsphericity, as measured by the nonsphericity parameter $F$, is independent of the ${{\ensuremath{\Gamma}}_{8}}^{+}$ electron concentration. The absolute value of $F$ for gray tin agrees closely with that for the ${{\ensuremath{\Gamma}}_{8}}^{+}$ bands of Ge. The $A$, $B$, and ${C}^{2}$ coefficients of Dresselhaus et al. and the related matrix-element sums ${F}^{\ensuremath{'}}$, ${H}_{1}$, and $G$ are evaluated. They are generally consistent in both sign and magnitude with the Groves-Paul band-structure model. The one exception is the positive matrix-element sum involving the ${\ensuremath{\Gamma}}_{12}$ band.
Azimuthal anisotropy of longwave and infrared window radiances from the Clouds and the Earth's Radiant Energy System on the Tropical Rainfall Measuring Mission and Terra satellites

[1] Shadowing by vegetation, landforms, or clouds can reduce the surface temperature relative to unshadowed portions of the same land area. This shading effect can cause azimuthal variation of the outgoing infrared radiance that is currently not taken into account in remote sensing and Earth radiation budget analyses. In this paper, multiangle longwave (LW) (5–200 μm) and window (WN) (8–12 μm) radiances taken by the Clouds and the Earth's Radiant Energy System (CERES) rotating azimuth plane scanner on the Tropical Rainfall Measuring Mission (TRMM) and Terra satellites are used to determine the azimuthal anisotropy of LW and WN fields over all solar zenith angles and surface types in clear and cloudy conditions. The azimuthal component of the anisotropy is isolated by constructing limb-darkening models for each category of surface type and topography in each solar zenith angle (SZA) bin. The viewing zenith angle dependence of WN and LW radiances in clear scenes depends on the SZA, possibly because of changes in the boundary layer temperature structure during the day. The observed mean radiances, in general, are greater when viewing the sunlit hemisphere (backscattering) than when viewing the shaded (forward scattering) hemisphere. This forward-back contrast increases with increasing terrain roughness and is stronger for surfaces with open vegetation such as shrubs and grass than for contiguous vegetation like forests. The anisotropy is less well defined for barren deserts. Maximum anisotropy occurs for SZAs between 48° and 70°. This paper provides the first evidence that clouds also induce longwave azimuthal anisotropy. Strong forward-back radiance contrast is evident for partly, mostly, and overcast scenes for SZA < 48°. The contrast disappears for overcast scenes and decreases for partly and mostly cloudy scenes at higher SZAs. The TRMM sampling is limited and causes some biases at particular angle sets but overall provides a reasonable depiction of the anisotropy at all SZAs. Terra yields a more accurate anisotropy characterization but only for SZAs between 48° and 70°. A simple model constructed from the TRMM results for clear scenes reduces clear-sky temperature prediction RMS errors by 38% or more while minimizing the biases associated with azimuthal anisotropy. The model should yield similar or better reductions in the errors associated with retrievals of skin temperature or LW fluxes, especially those from geostationary satellites. In addition, future analyses of combined TRMM, Terra, and Aqua CERES data will likely provide more accurate correction models that could further reduce errors in surface skin temperature and radiative flux for both clear and cloudy scenes.
The contribution of emotional characteristics to breast cancer screening among women from six ethnic groups.

Background. This study was designed to determine which of several emotional propensities were associated with the frequency of mammograms and clinical breast exams among six groups of minority women. Three emotion-related variables that have been identified in the previous literature as influencing screening were examined: Repression, cancer worry, and embarrassment. However, these variables have never been examined within the same study, nor where relevant background variables are controlled. Methods. 1364 African American, US-born white, English-speaking Carribean, Haitian, Dominican, and Eastern European women were recruited via stratified-cluster sampling. Participants provided demographics and measures of beliefs and knowledge. Results. As expected, self-regulation and cancer worry were both positively associated with mammogram and clinical breast exam frequency, while embarrassment regarding having a mammogram was negatively associated with screening. These results held even after controlling for demographic variables and the presence or absence of physician recommendation. Screening rates for African American women equaled or exceeded the rates for European Americans. Other minority subpopulations had even lower screening rates, including women from the English-speaking Caribbean and Haitians. Conclusions. Results are discussed in terms of their implications for screening intervention, models of health behavior, and the need for more precise operationalizations of ethnicity in screening research.
The stability of thiamine hydrochloride and mono-nitrate in parenteral vitamin B complex and iron solutions

Vitamin B1, in parenteral solutions in admixture with riboflavin and niacinamide, exhibits maximum stability with respect to potency and clarity of solution at pH 4 under a nitrogen atmosphere. In admixture with iron compounds, vitamin Bi is more stable in the presence of ferrous gluconate than of iron peptonate or ferric ammonium citrate. The optimum pH is 4. Of the specific grades studied, thiamine mononitrate is somewhat more stable than the hydrochloride in the above solutions.
Overview of resistant gram-positive pathogens in the surgical patient.

Staphylococci and enterococci are the most common pathogens in surgical-site and bloodstream infections. The emergence of drug resistance among these gram-positive bacteria thus poses a substantial...
Improved IR image generator for real-time scene simulation

Technology Service Corporation (TSC) improved the image generator portion of an IR scene simulator that is used for dynamic, real-time, hardware-in-the-loop testing of an IR sensor system. This paper describes the IR simulator prior to its improvement, the goals that were set for the image generator upgrade, and the resultant improved IR simulator, including its new features (e.g., antialiasing, smooth shading, and texture). The steps involved in computing an IR scene are also discussed, as are the software models used to generate the IR scene and an alternative test equipment configuration that was devised for the simulator.
THE MOLECULAR STRUCTURE AND PSEUDOROTATIONAL MOTION OF GASEOUS DECAMETHYL CYCLOPENTASILANE

The molecular structure of decamethyl cyclopentasilane has been determined in the gas phase at a nozzle temperature of 85°C. The geometrical parameters obtained from least squares refinements are: r(SiSi) = 2.358(3) A, r(Si1bC) = 1.898(2) A, q=0.68(4)A, < CSiC = 110(2)°, < HCSi = 111(1)°, and t(HCSiSi) = 28(8)°. The data are consistent with a pseudorotational model and a model with the presence of both the twist and envelope forms.
The electronic properties of high Tc superconductors probed by positron annihilation

The discovery of superconductivity at 30K in Ba{sub .6}K{sub .4} BiO{sub 3} has generated considerable excitement in view of the contrasting properties of the Ba-K-Bi-O system when compared to the well known Cu-O based high temperature superconductors. Positron annihilation spectroscopy, which is a sensitive local probe of the electronic and defect properties of a solid, has been extensively applied in the study of Cu-O based superconductors. In the present paper, the results of positron lifetime as a function of temperature in Ba-K-Bi-O are presented and compared with the known results in the cuprate superconductors. Plausible reasons for the observed temperature dependence of positron lifetime are presented. 7 refs., 2 figs.
Die NO‐katalysierte Isomerisierung von 3‐Methylen‐1,5,5‐trimethyl‐cyclohexen zu 1,3,5,5‐Tetramethyl‐1,3‐cyclohexadien in der Gas‐Phase. Thermodynamische Daten aus Gleichgewichtsmessungen

The composition of equilibrated gaseous mixtures of 3-methylene-1,5,5-trimethylcyclohexene (MTC) and 1,3,5,5-tetramethyl-1,3-cyclohexadiene (TECD) have been measured for temperatures ranging between 302 and 410°C. Nitrogen oxide was used as catalyst. Equilibrium was approached from either side. The least squares regression analysis of the observed temperature dependence of the equilibrium constants K1.2 = k1/k2 = (TECD)eq./(MTC)eq. yields (with standard errors) This results in ΔH1.2(300°K) = 0.4 ± 0.3 kcal/mole and ΔS1.2(300°K) = 1.4 ± 0.8 cal/°-mole. The fact that the reaction is practically thermoneutral implies that the secondary, «biallylic» CH bond in MTC is equally strong as the primary «biallylic» CH bond of the 1-methyl group in TECD. The observed enthalpy and entropy differences between the two isomers are in agreement with prediction based on the concept of additivity of thermodynamic increment properties (ref. [5]). The results of this work also yield a value of 23.7 cal/°-mole for the entropy contribution characteristic of the 1,3-cyclohexadiene ring structure. When combined with the ARRHENIUS parameters, reported earlier [1] for k1, the results of this work yield for the back reaction log k2 (1/mole-s) = 8.25–30.2/4.58 × 10−3T(°K).
Equines and their human companions

Abstract Previous research related to marketing describes deep emotional bonds that develop between humans and their pets (primarily cats and dogs). Another multi-billion-dollar international market that needs exploration flows from the highly-involving bonds between humans and their horses. Horses are not pets, but the study of equine relationships with humans generates insights into animal-companion interactions. This article reports results of an interpretive phenomenological investigation of the relationship between humans and their horses, using participant observations, in-depth interviews, and written open-ended questions including the critical-incident technique. Analysis of the data first addresses a priori themes from the animal-companionship literature and identifies themes found, themes with a twist, and themes not found. The article then discusses seven emergent themes unique to human–horse relationships — including physicality, partnership, bonding through adversity, flow experience, communitas, spirituality, and life lessons.
Interaction effects of performance and money on self-perception of intrinsic motivation

Abstract The self-perception hypothesis that payment for performance of an interesting task decreases intrinsic motivation was tested on a roadracing task under various conditions of performance. Performance was controlled to give subjects the experience of reaching criterion after producing either many errors (poor performance) or few errors (good performance). Good performers reported liking and enjoying the task more when not paid for their performance than when paid; poor performers reported greater liking and enjoyment when paid than when not. On the other hand, good performers were more satisfied with their performance when paid than when not and attributed their performance more to their personal strategies; the opposite was the case for poor performers. This latter finding contradicts the hypothesis that subjects decrease their intrinsic motivation when paid because payment detracts from their feeling of personal causation. An alternative interpretation is that subjects are less intrinsically motivated when the task is perceived as easy relative to their ability. Supporting that interpretation, the present study found that good performing low error subjects perceived the task as less difficult than poor performing high error subjects, and, in addition, paid subjects perceived their experience on the task to be greater than did unpaid subjects.
Frequency control in unstable and pulse combustors

The main objective of the experimental and theoretical investigations reported in this paper has been to develop capabilities for controlling the behavior of unstable and pulse combustors. In pursuit of this objective, the dependence of an unsteady combustor behavior upon the phase difference between the heat release rate and pressure oscillations has been investigated. Propane-air mixtures were burned in a two dimensional combustor and the phase of the heat release rate oscillations was varied by changing the relative positions of two circular flame holders which stabilized the combustion process. The combustor performance was determined from CH radiation and acoustic pressure measurements. Simultaneously, a theoretical model of the investigated combustor has been developed and used to predict the dependence of the excited combustor pressure oscillations upon the unsteady heat release rate. Trends predicted by the model are in qualitative agreement with measured data. The results of this study are consistent with existing approaches for controlling the oscillations in unstable and pulse combustors.