cssi/SciSciGPT-SciSciNet huggingface dataset:
Solvent effects in the substitution reactions of trans-Pt(C5H5N)2Cl2

Abstract The rates of nucleophilic substitution in trans -Pt(C 5 H 5 N) 2 Cl 2 were determined as a function of solvent composition in dimethylsulfoxide (DMSO) and dimethylsulfoxide-water mixture. The results of these measurements combined with an investigation of solvent isotope effect suggest that leaving group solvation, or some similar process involving hydrogen bonding, plays a kinetically important role in these reactions. For example, the second-order rate constants for thiourea as a nucleophile are 0·64, 0·71, and 0·991. mole −1 sec −1 in DMSO and DMSOD 2 O or DMSOH 2 O containing 0·18 mole fraction of the aqueous component respectively.
Actin polymerization overshoots and ATP hydrolysis as assayed by pyrene fluorescence.

We investigate via stochastic simulation the overshoots observed in the fluorescence intensity of pyrene-labeled actin during rapid polymerization. We show that previous assumptions about pyrene intensity that ignore the intensity differences between subunits in different ATP hydrolysis states are not consistent with experimental data. This strong sensitivity of intensity to hydrolysis state implies that a measured pyrene intensity curve does not immediately reveal the true polymerization kinetics. We show that there is an optimal range of hydrolysis and phosphate release rate combinations simultaneously consistent with measured polymerization data from previously published severing and Arp2/3 complex-induced branching experiments. Within this range, we find that the pyrene intensity curves are described very accurately by the following average relative intensity coefficients: 0.37 for F-ATP actin; 0.55 for F-ADP + Pi actin; and 0.75 for F-ADP actin. Finally, we present an analytic formula, which properly accounts for the sensitivity of the pyrene assay to hydrolysis state, for estimation of the concentration of free barbed ends from pyrene intensity curves.
CWD After “the Fire”: Six Reasons Why Hunters Resisted Wisconsin's Eradication Effort

Eight years after undertaking an unprecedented attempt to eradicate chronic wasting disease (CWD) from its free-ranging white-tailed deer (Odocoileus virginianus) population, Wisconsin wildlife man...
Ethnic identity and acculturation in Hispanic early adolescents: Mediated relationships to academic grades, prosocial behaviors, and externalizing symptoms.

This study examined acculturative stress and self-esteem as mediators of the association of ethnic identity and acculturation with psychosocial outcomes. The study sample consisted of 347 Hispanic adolescents in a "new" immigrant-receiving community in the Midwest. The authors expected acculturation to influence psychosocial adjustment through acculturative stress and ethnic identity to influence psychosocial adjustment through self-esteem. Results indicated that relationships of ethnic identity to academic grades and to externalizing symptoms were mediated by self-esteem and that both U.S. and Hispanic acculturation orientations were directly associated with prosocial behavior. The relationships of U.S. cultural orientation to academic grades and to behavior problems were mediated through acculturative stress and self-esteem. Implications of these findings for the study of Hispanics in more monocultural receiving communities are discussed.
Large Stark effects for transitions from local states to global states in quantum well structures

The electric-field dependence of the optical absorption for the type of quantum well structure in which one or more small wells are embedded in a big well is discussed. In such structures, local energy states confined by the small well(s) and global states confined by the big well have different electric-field dependences while their wave functions remain overlapped. Thus, a large Stark effect (large energy shift and oscillator strength) can be achieved for the optical transition from a local state to a global state. This concept of using the local and global states can be applied to both interband and intersubband transitions. For intersubband transitions, a typical 10-20 meV shift is predicted, compared to a reported 1.1 meV blue shift at the field 30 kV/cm. For interband transitions, the Stark shift is larger than that in the single quantum wells. >
Spatially resolved temperature measurements of electrically heated carbon nanotubes.

Spatially resolved Raman spectra of individual pristine suspended carbon nanotubes are observed under electrical heating. The Raman G+ and G- bands show unequal temperature profiles. The preferential heating is more pronounced in short nanotubes (2 µm) than in long nanotubes (5 µm). These results are understood in terms of the decay and thermalization of nonequilibrium phonons, revealing the mechanism of thermal transport in these devices. The measurements also enable a direct estimate of thermal contact resistances and the spatial variation of thermal conductivity.
Exposure latitude requirements for high yield with photon flux-limited laser sources

This paper presents an analysis of quantum statistical limits on photolithographic imaging of very large arrays of semiconductor features. In flux limited imaging systems the photon counting statistics contribute to the overall process variation. There is a direct relationship between exposure latitude and sensitivity to photon counting statistics. For example, in an array of 1 million 90 nm contact holes imaged with 20 mJ/cm 2 of 157nm light 1350 of these holes will receive a total dose less than 98% of the mean dose. If the exposure latitude is 4% then these 1350 contacts will print out-of-spec as a result of the Poisson statistical distribution of photon-limited light sources (sometimes called shot-noise). High yield for volume semiconductor manufacturing requires failure rates well below this level. Each new device generation requires more functional transistors than the previous one, increasing approximately linearly. As the imaging wavelength decreases the net number of photons available decreases linearly (assuming constant laser power). The area of a contact hole decreases as the square of the critical dimension. Thus the fraction of chips with at least one contact hole receiving inadequate dose increases approximately as the fourth power of the wavelength. This presents serious implications for 157nm lithography semiconductor yield. Electron imaging systems are not immune to this either, Poisson limited intensity uniformity is nearly identical with that of optical imaging. 157 nm lithography is marginal to photon-statistics limited yield, and 13 nm EUV lithography yield is almost certainly photon limited. In addition, as transistor array size increases the 0.987 ppb failure rate of a 6-sigma process will not be sufficient for high yield. Thus 8 or 9-sigma processing will be needed along with significant improvement in exposure latitude and optimized resist sensitivity will be necessary.
Cell Sensing and Response to Micro- and Nanostructured Surfaces Produced by Chemical and Topographic Patterning

Chemical and topographic substrate surface patterning is recognized as a powerful tool for regulating cell functions. We discuss the relative role of scale and pattern of chemically and topographically patterned surfaces in regulating cell behavior. Chemical patterning achieved using spatial cell-adhesive molecular organization regulates different cell functions depending on its scale (micropattern for cell patterning and derived cell functions, nanopattern for collective cell functions such as adhesion, proliferation, and differentiation). In chemical patterning, a direct and specific cell-sensing mechanism such as integrin-ligand binding governs. Alternatively, topographic modification affects different cell functions depending on its pattern (anisotropic ridges and grooves for contact-guided cell alignment, isotropic textures having randomly or evenly distributed topographic features for collective functions). For all topographic patterns, micro- or nanotopographic scale determines whether specific cel...
Just a cog in the machine: participatory robotics as a tool for understanding collaborative learning and decision-making

We will demonstrate the integration of a software-based multi-agent modeling platform with a participatory simulation environment and a real-time control system for a physical robotic agent. Both real and virtual participants will be able to act collaboratively in a simulation that will control a physical agent. The backbone of this demonstration is a widely used, freely available, mature modeling platform (NetLogo). We posit that this technological platform can be of use for researchers interested in investigating collaborative learning and decision-making, as well as to design collaborative learning activities. We will present preliminary findings from pilot studies with the tool.
AN ECONOMIC ANALYSIS OF INDUSTRIAL REVENUE BONDS AND THE DEMAND FOR LABOR

In this paper the standard theory of the derived demand for inputs for the firm has been used to examine the effect on employment of a subsidy to the capital input via an industrial revenue bond. While the effect theoretically is ambiguous in sign, an empirical examination of the industrial revenue bond program in Chicago suggests that, ceteris paribus, employment does increase in firms selected for the program. The estimates of the arc crosselasticity of demand for labor for the groups of firms that participated in the Chicago program range from −.27 to −1.07. Systematic variations in the cross elasticity of demand for labor are found.
The Pleiades and α Persei Clusters

The upper–main-sequence members of the Pleiades and α Persei clusters, considered as members of the Local Association, yield mean parallaxes that are only 4% larger than the mean values from Hipparcos observations. The (log Teff, MV) diagram reveals that in the temperature range from 6000 to 8000 K, the Hyades and α Persei main-sequence members are nearly identical and several tenths of a magnitude brighter than similar stars on the Pleiades main sequence. The departure of the Pleiades main sequence cannot be traced to either age or heavy-element abundance differences in the range thought to apply to these clusters. A 50% increase in the helium abundance of Pleiades over Hyades stars could account for the luminosity difference. Alternative explanations are that the Pleiades cluster is rejected from supercluster membership and/or that the Hipparcos parallax results for the Pleiades are in error by some 10%.
Predictors of African American Representation in Municipal Government

This article presents the results of a path analysis that investigates the explanatory power of five new predictors of African American representation in city government against eight traditional predictors of representation in municipal government. The findings generally indicate that the percentage of African Americans in the city population and African American personnel directors are the most consistent predictors of African American representation in municipal civil service. African American actors in the internal environment of the personnel game—personnel directors, administrators, mayors, and council members—are also generally more predictive of African American representation in city government than variables in the external environments of municipalities.
Characterization of Starburst Dendrimers by the EPR Technique. Copper(II) Ions Binding Full-Generation Dendrimers

Cu(II) was used as a probe to investigate the structure and ion binding ability of full-generation poly(amidoamine) starburst dendrimers (nSBDs). Computer-aided analysis of the EPR spectra provided information on the formation of copper complexes in various internal or external locations of the dendrimers, as well as the nSBD structure as a function of the size (generation) of the dendrimers, pH, temperature, Cu(II) concentration, and aging of the samples. At low pH, Cu2+ competes with protons for binding with external amino groups, which become available for complexation at pH > 3.5. The Cu(H2O)62+ complexes are localized in proximity to the SBD surface, where structural modifications of the water solution prevented the occurrence of a freezing transition. A portion (about 20%) of Cu(H2O)62+ resides in the water pools in the open structure of the earlier generation dendrimers (G < 4) and are capable of undergoing a freezing transition. Progressive penetration of Cu2+ ions into the SBD structure occurs wi...
The application of fluid inclusions to migration of oil and diagenesis in petroleum reservoirs

Abstract Fluid inclusions can be used to interpret thermal history and petroleum maturation and migration relative to burial history. Temperature, pressure and composition data collected from fluid inclusions are used to determine the environment of diagenesis and the timing of cementation and migration. Cements in petroleum reservoirs contain both oil and aqueous fluid inclusions. Fluorescence spectroscopy is used to identify oil inclusions and to determine the maturity of entrapped oil. The lifetime of fluorescence induced by a pulsed laser is related to the API gravity of entrapped oil. Interpretation of fluid inclusion data depends on knowing the origin of fluid inclusions and the probability that they survive in the burial environment. Those aspects of fluid inclusion study are investigated by synthesizing oil and aqueous inclusions in calcite crystals in laboratory experiments. Examples of how fluid inclusions are used to determine the physico-chemical environments of diagenesis in petroleum reservoirs and the timing of cementation and migration are given for the Wealden Basin, England, the Mishrif Formation, Dubai, the Smackover Formation, Gulf Coast, U.S.A. and Jurassic sandstones, offshore Norway. In the Wealden Basin, temperature data from fluid inclusions are used to determine that oil migration occurred in the Cretaceous and that the reservoir rocks have been uplifted to varying degrees at a time after migration. Distribution of oil inclusions indicates that generation and migration of oil was principally in the western part of the basin. The geochemistry of oil inclusions in calcite cements from the Mishrif Formation, Dubai, are used to determine the type and maturity of entrapped oil. Temperature data from oil and water inclusions are used to relate reservoir diagenesis to burial history and the migration of oil. In deep Smackover reservoirs oil contains H 2 S. The origin of the H 2 S is examined by study of fluid inclusions containing H 2 S. In Jurassic sandstones, offshore Norway, fluid inclusion studies show that silica cementation is related to burial depth whereas a later calcite cementation originated from invasion of a hot fluid.
Index-based object recognition in pictorial data management

We have been involved with formulating query processing strategies for an object-oriented, integrated, textual/iconic database management system. For this task, model-based representations of images by content are being used, as well as a new, efficient object recognition approach which also permits the efficients insertion and deletion of object models, called data-driven indexed hypotheses. This paper emphasizes the data management aspects of this approach: the insertion and deletion of object models, a performance/space trade-off which can be used to improve the recognition capabilities of our approach, and a secondary memory implementation of our approach
Chronic atrial fibrillation unrelated to organic heart disease: Follow-up study of five cases

Abstract Five cases of chronic functional atrial fibrillation observed for periods ranging from 11 months to 14 years are reported. Evidence for organic heart disease has not been substantiated. Four of the patients require permanent digitalis therapy, one of whom had been in frank congestive failure. Each of the patients reported has a personality disorder confirmed by psychiatric evaluation. The literature pertaining to idiopathic atrial fibrillation has been reviewed.
Mushroom-Derived Maitake PETfraction as Single Agent for the Treatment of Lymphoma in Dogs

Background: Maitake PETfraction is a standardized essence extracted from the mushroom Maitake (Grifola frondosd) that has antitumor activity in tumor-bearing mice. In addition, PETfraction induces apoptosis in human prostate and bladder cancer cells and suppresses the proliferation in vitro of several canine tumor cell lines, such as lymphoma (Cl-1), mammary gland (CF33), and connective tissue (CF21). Hypothesis: Maitake PETfraction is effective as a single agent in dogs with lymphoma. Animals: Fifteen dogs with confirmed intermediate or high-grade lymphoma were enrolled into this prospective, noncontrolled, clinical trial. Inclusion criteria were an expected survival time of at least 2 weeks and no major organ dysfunction. Methods: Maitake PETfraction was administered at a dose of 3 drops/kg/day divided into 2 doses given 1 hour before feeding. Dogs were evaluated by physical examination with tumor measurement, body weight, CBC, and chemistry profile before treatment and after 2, 4, 8, and 12 weeks. At each visit, owners completed a questionnaire addressing overall quality of life, appetite, and any adverse effects noted. Results: A decrease in lymph node size of greater than 50% (objective response) was not seen in any of the dogs. Thirteen dogs developed progressive disease before the 4th week. The median treatment duration was 27 days (range, 9–228). PETfraction was well accepted, and minimal adverse effects were observed. Two dogs developed hyphema. It was not known if this was related to progressive lymphoma or was an adverse effect of treatment. Conclusions: No objective responses were observed to administration of Maitake PETfraction, and the drug was well tolerated in these dogs.
Reducing polynomial matrices to canonical form

Abstract A canonical form for polynomial matrices first proposed by Eckberg is examined and simplified. Three distinct algorithms to reduce a polynomial matrix to this canonical form are proposed and shown to converge in a finite number of steps. Further it is shown that any such reduction algorithm based upon column subtraction will be finite. The computer implementation of the three algorithms is discussed and the results of a large number of test examples are presented. Attention is focused on the dual problems of operation count and numerical stability of the algorithms.
Effects of a Lumbar Belt on Neuromotor Transmission of Whole Body Vibration

Whole body vibration (WBV) has been identified as a risk factor for low back musculoskeletal disorders and injuries. One potential mechanism by which WBV may lead to low back injury is through stimulation of muscle spindle organs and repetitive activation of the stretch-reflex neuromotor response. Such repetitive activation could lead to muscular fatigue and/or neuromotor adaptation. Understanding mechanical transmission of vibration to the neuromotor system and the resulting neuromotor activation is critical to understanding these mechanisms. In this study, it was theorized that activation of the extensor musculature of the low back is a response to the lengthening and shortening of the extensor musculature. This lengthening and shortening of the extensor musculature may be the result of flexion-extension rotation in the lumbar spine. By measuring lumbar flexion and extension, the amplitude and phase of this lengthening and shortening were assessed. Using electromyographic data from the erector spinae muscle groups at the L2/L3 lumbar level, the cyclic activation of the extensor musculature was also measured. Neuromotor transmission was observed over a frequency range of 3–20 Hz and vibration magnitudes of 1 and 2 m/s^2 RMS. Resonance peaks in lumbar flexion-extension and the integrated electromyographic data were observed at 4 Hz and 10–12 Hz. A lumbar belt was used to reduce transmission of axial seat-pan vibration to lumbar flexion-extension and to observe the changes in cyclic electromyographic activity. The lumbar belt was found to decrease both lumbar flexion-extension and paraspinal muscle activity demonstrating a link between axial seatpan vibration, lumbar flexion-extension and the cyclic activation of the neuromotor system. These results provide information on the neuromotor effects of WBV and may be used to design better low back injury prevention methods.© 2007 ASME
General Aptitude Test Battery Factor Structures for Saudi Arabian and American Samples : A Comparison:

The General Aptitude Test Battery (GATB) has been used in America for over 45 years and administered abroad in 13 languages in 35 countries, including an Arabic version. Correlation matrices for the 12 GATB tests for samples of 4,000 Americans and 749 Saudi Arabians were analysed by factor and cluster analysis. The resulting factor structures and group mean score profiles are contrasted. Three similar factors emerged (Cognitive, Psychomotor and Spatial Perception) for both samples and factorial equivalence established. The profiles of mean scores for the two groups are similar in both shape and amplitude.One can have confidence in the results when an Arabic version of the GATB is administered to Saudi Arabian males. Further study should be made of tests measuring the Spatial Perception construct, so that this important ability dimension can be used with greater precision with Saudi Arabian males for selection, counselling, and training.
Implementing New Dietary Guidelines of the National Cholesterol Education Program

The aggregate cost of coronary heart disease in the United States is between $50 billion and $100 billion per year. The most cost-effective method of reducing this is by health education. In 1993, the National Cholesterol Education Program released its second report containing the updated recommendations for the evaluation and treatment of people with high levels of total cholesterol and low-density lipoprotein cholesterol. The new guidelines emphasize the importance of maximizing the benefits of nondrug therapies (e.g., diet, weight loss, and exercise) before adding pharmacologic therapy. The nutrition counselor teaches clients the National Cholesterol Education Program dietary guidelines through assessing, motivating, implementing, and monitoring adherence and therapeutic response. It is important to stress which foods to use or decrease and to give specific examples that apply in everyday life. The addition of drug therapy should be considered carefully and reserved for high-risk patients, only after sufficient application of dietary therapy, weight control, and physical exercise have been attempted.
Thermal Destruction of Cysteine and Cystine Residues of Soy Protein under Conditions of Gelation

Thermal destruction of cysteine and cystine residues of soy proteins was investigated under gelation conditions. Significant cysteine and cystine were lost as a function of heating time. The rate and extent of loss was affected by heating temperature, pH, salt concentration and viscosity of the protein solution. Greatest effects were from heating temperature, pH and viscosity. A significant amount was lost even at pH 7.0 at 100°C. Amino acid analysis revealed that thermal destruction of cysteine and cystine at high protein concentration and near neutral pH did not result in formation of lysinoalanine. The results can be useful to preserve nutritional quality in thermal processing of soy proteins.
SPADE: A rock‐crushing and sample‐handling system developed for Mars missions

[1] A novel system has been developed to access and analyze the interior of rocks on Mars by crushing rocks. A miniature rock crusher has been prototyped along with a method for distribution of the fines and fragments produced by the rock crusher to inspection and analysis instruments. The science goals and advantages of this approach are substantial with respect to understanding the geologic and climate history of Mars via the investigation of its mineralogy and petrology. The system is described in detail, and results of various performance metrics are reported. Engineering considerations, constraints on functionality, fault tolerance, and its previously-planned deployment on the 2009 Mars Science Laboratory mission are described.
On the computation of mixing coefficients between discrete-valued random variables

Mixing coefficients between two random variables act as a measure of their dependence. For stochastic processes mixing is another way of saying that the process is asymptotically independent. To measure mixing different types of mixing coefficients are introduced. In the literature, three kinds of mixing coefficients are commonly used, namely α-, β- and φ-mixing coefficients. While it is easy to derive an explicit closed-form formula for the β-mixing coefficient, no such formulas exist for the a- and the φ-mixing coefficients. We study the case where the two random variables assume values in a finite set. Under this setup, we show that the computation of alpha-mixing coefficient is NP-hard. Moreover, by using a semi-definite relaxation we obtain lower and upper bounds for the alpha-mixing coefficient. We also derive a closed form expression for the phi-mixing coefficient between two random variables. These results generalize earlier results by the authors.
Interferometric versus confocal techniques for imaging microstructures in turbid biological media

In this paper we compare the performance of confocal and optical- coherence (OC) microscopes designed for imaging structures in a dense biological tissue, like skin, to depths greater than several hundred micrometers. Simple theoretical models, supplemented by Monte-Carlo simulations, are developed for evaluating the optical-sectioning capabilities of the two types of microscopes. The OC microscope is shown to exhibit superior rejection of undesired scattered light when the available angular field of view is restricted. Results of experimental studies with tissue phantoms show a progressive degradation with optical depth in the contrast of objects viewed by a confocal microscope compared to that achieved with the heterodyne technique. We conclude by making a few observations and generalizations regarding the suitability of OC and confocal techniques for potential in-vivo applications.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
The Assemblage of Birds Foraging in Native West Indian Pine (Pinus occidentalis) Forests of the Dominican Republic during the Nonbreeding Season1

We studied avian resource use in a native West Indian pine (Pinus occidentalis) forest in the Cordillera Central of the Dominican Republic during the nonbreeding season. The forest is characterized by a fairly open pine canopy and a dense mixed-broadleaf and pine understory. We used a principal components analysis of 23 foraging characters for 23 bird species, including foraging height, the proportional use of 5 different foraging methods, 3 horizontal positions and foliage densities, and 11 foraging substrates. Five principal components accounted for 74 percent of the total variance of the assemblage variables and resulted in the delineation of at least 5 foraging guilds. 78 percent of bird species had mean foraging heights of 5.0–10.0 m, corresponding to the region of overlap of pine and broadleaf vegetation. As a result, the diversity of foraging substrates and maneuvers used by birds, rather than foraging height, appears to be the primary means by which birds that exploit this habitat separate ecologically. Migrant wood warblers (Parulinae) are probably able to integrate into the community because of little diet overlap between residents and migrants, and the fairly specialized nature of their largely insectivorous foraging habits. Avian foraging in this habitat may reflect the effects of frequent disturbance such as hurricanes. RESUMEN Estudiamos el uso de recursos por aves en un bosque de pino nativo (Pinus occidentalis) en la Cordillera Central de la Republica Dominicana durante la epoca de no-reproduccion. El bosque se caracteriza por un dosel de pino bastante abierto, con pinos y arbustos mixtos y densos en las clases de vegetacion de alturas mas bajas. Utilizamos un analisis de componentes principales de 23 caracteres de comportamientos alimenticios para 23 especies, incluyendo la altura de alimentacion, el uso proporcional de cinco metodos de comportamientos alimenticios, tres posiciones horizontales y clases de densidades de los arbustos, y once substratos de alimentos. Cinco componentes principales explicaban 74 por ciento de la variacion total entre las 23 especies y delineaban por lo menos cinco guildas de alimentaciones. 78 por ciento de las especies de aves tenian una altura media de alimentacion de 5.0–10.0 m, coincidiendo con la region de traslapo de pinos y arbustos. Como consecuencia, la diversidad de substratos de alimentos y metodos de comportamientos alimenticios utilizados por las aves, en vez de la altura de comportamientos alimenticios, es la manera principal en que las aves utilizando este habitat separaban los nichos ecologicos. Aves migratorias (Parulinae) probablamente pueden integrarse en la comunidad porque hay poco traslapo de alimentaciones entre los residentes y migrantes, y sus comportamientos alimenticios estan bastante especializado. Es posible que el comportamiento alimenticio de aves en este habitat refleja los efectos de perturbaciones frecuentes como huracanes.
Prostate-specific antigen levels in relation to cadmium exposure and zinc intake: results from the 2001-2002 National Health and Nutrition Examination Survey.

BACKGROUND. Cadmium exposure has been suggested as a risk factor for prostate cancer, and experimental literature suggests that the carcinogenic effect of cadmium is modified by the presence of zinc. We evaluated total prostate-specific antigen (PSA) levels in relation to urinary cadmium concentrations and dietary zinc intake. METHODS. PSA levels were determined in 1,320 men over the age of 40 in the 2001-2002 National Health and Nutrition Examination Survey (NHANES). Urinary cadmium concentrations were measured in about one-third of the sample population, whereas dietary zinc intake was based on participants' 24-hr recall. Information on all three variables was available for 422 men in the 2001-2002 NHANES survey. We performed linear regressions to evaluate the relationships these factors after accounting for age and other covariates. RESULTS. Little evidence for an association between cadmium and elevated PSA level was observed. However, the data provide suggestive evidence for an interaction between zinc intake and cadmium exposure (P for interaction = 0.09). Among men with zinc intake less than the median level of 12.67 mg/day, an increase in 1 μg/g creatinine cadmium exposure was associated with a 35% increase in PSA level. In contrast, among men with greater than median zinc intake, little evidence for an association between cadmium and PSA was found. CONCLUSIONS. These findings suggest a protective effect of zinc intake on cadmium-induced prostatic injury, and may provide further rationale for investigating the impact of these factors individually and jointly on the etiology of prostate cancer.
SU‐E‐I‐12: Analysis of Image Noise in 3D Scatter Corrected Cone Beam CT Images as a Function of Object Size

Purpose: To characterize the spatial correlation of quantum noise of a cone beam CT(CBCT) system for breast imaging under scatter and non‐scatter corrected conditions as a function of object radius. Methods: Experiments were conducted using a conical phantom under scatter and non‐scatter corrected conditions. The cone phantom filled with 700ml of water was positioned near the isocenter of the quasi‐monochromatic CBCTimaging system. 360 projections were acquired and beam‐stop measured scatter correction was performed. Both scatter and non‐scatter corrected projections were reconstructed with an iterative ordered subsets convex (OSC) algorithm. NPS measurements were made at several cone radii (6–12cm) using 4 overlapping 50×50 pixel ROI's with a 50% overlap between adjacent ROIs. An ensemble average of NPS measurements was taken over 5 slices at each radius. Results: For both scatter and non‐scatter corrected data overall noise is higher with increasing object radius. Each 1‐D NPS area under the curve was found to be within the standard deviation of the respective ROI variance. The variance of scatter corrected images is higher at each radius. The 1‐D NPS indicates a decrease in peak value for both scatter and non‐scatter corrected images as radius increases. Scatter corrected NPS shows a slight shift in the peak towards higher spatial frequencies, and a larger spread of noise over all spatial frequencies as radius increases. Conclusions: This work demonstrates that scatter correction increases noise at each spatial frequency at various object radii. owever as radius increases, lower frequency noise decreases and concomitantly higher frequency noise increases. As a Result of this equalization of noise across spatial frequencies, the noise texture appears more uniform at larger radii under scatter corrected conditions. These results and methodology can be used to determine optimal detection of low contrast signals in phantoms of different radii and with clinical breast data.
Preschool programs in historical perspective

This paper compares two fundamentally different types of preschool programs—the academic preschool and the modern American nursery school—with a view to identifying issues that contribute to divergent points of view about early education. Discussion includes the influences from other fields of study and the points of convergence and divergence in the two models. The author sees the major differences as the interpretation of the role played by the teacher in the learning experience, of the child. Other differences emerge from the manner in which this concept is implemented. The history of the development of the teacher-child relationship emphasis is a significant aspect of the paper.
A sensitive qualitative test for sulphoxides on paper chromatograms.

A NUMBER of sulphoxides have been found to occur naturally in plants1 (for example, alliin, s-methyl-L-cysteine sulphoxide, glucoiberin). To aid in the detection of sulphoxides on paper chromatograms, a specific sensitive test has been devised. The test, which is based on the reaction of sulphoxides with hydriodic acid to form iodine2, is presented here.
Measurement of the optical constants of crystal quartz in the far infrared with the asymmetric Fourier-transform method

The optical constants of crystal quartz in the far infrared (10–400 cm−1) are presented along with the dispersion parameters for the two ordinary-ray bands measured in this study. The asymmetric Fourier-transform method was used for the quantitative measurement of the refractive indices of quartz. The advantages of this method as compared with the channeled-spectrum method usually employed for refractive-index measurements in the far infrared are discussed. The extrapolated, zero-frequency refractive indices of quartz are n0(0)=2.106±0.001 and ne(0)=2.154±0.001. A pseudocoherence effect is described which permits the measurement of the difference of the principle refractive indices in a birefringent sample without the use of a polarizer.
Examining the link between forms of bullying behaviors and perceptions of safety and belonging among secondary school students

Research suggests that students who bully may perceive the school climate less favorably. Person-centered analyses were used to identify distinct groupings of bullying behaviors and related social–emotional factors (i.e., victimization, internalizing, and perception of school and bullying climate). Latent class analyses were conducted on a sample of 10,254 middle and 2509 high school students and indicated four classes in middle school (Low Involvement, Verbal, High Physical/High Verbal, and High Involvement) and three classes in high school (Low Involvement, Verbal, and High Involvement). A Low Involvement bullying class characterized most students and was related to positive adjustment, whereas a High Involvement bullying class represented the smallest proportion of the sample (1.6% middle school and 7.3% in high school). Students in the High Involvement class reported increased victimization and internalizing problems, feeling less safe and less belonging, and perceiving the school climate to be more supportive of bullying (i.e., perceiving adults' prevention and intervention efforts as ineffective). In middle school, the High Physical/High Verbal class reported significantly higher levels of victimization as compared to the Verbal class. Findings highlight heterogeneity in bullying behaviors and underscore the importance of prevention and intervention programming that addresses safety and belonging.
Cytomegalovirus-induced sensorineural hearing loss with persistent cochlear inflammation in neonatal mice

Congenital cytomegalovirus (CMV) infection is the leading cause of sensorineural hearing loss (SNHL) in children. During murine (M)CMV-induced encephalitis, the immune response is important for both the control of viral dissemination and the clearance of virus from the brain. While the importance of CMV-induced SNHL has been described, the mechanisms surrounding its pathogenesis and the role of inflammatory responses remain unclear. This study presents a neonatal mouse model of profound SNHL in which MCMV preferentially infected both cochlear perilymphatic epithelial cells and spiral ganglion neurons. Interestingly, MCMV infection induced cochlear hair cell death by 21 days post-infection, despite a clear lack of direct infection of hair cells and the complete clearance of the virus from the cochlea by 14 dpi. Flow cytometric, immunohistochemical, and quantitative PCR analysis of MCMV-infected cochlea revealed a robust and chronic inflammatory response, including a prolonged increase in reactive oxygen species production by infiltrating macrophages. These data support a pivotal role for inflammation during MCMV-induced SNHL.
Self-consistent tight-binding method

A self-consistent tight-binding formalism is described. The self-consistency is achieved by the introduction of a chemical hardness matrix and a generalization of the H\"uckel model to make the tight-binding Hamiltonian an implicit functional of the charge density. Studies of the band structures of diamond and face-centered cubic Si demonstrate that the method has very good transferability and shows promise for applications to systems involving large charge transfer. Also, the method can easily be implemented to study spin-polarized systems.
Association between SLC2A9 transporter gene variants and uric acid phenotypes in African American and white families

Objectives. SLC2A9 gene variants associate with serum uric acid in white populations, but little is known about African American populations. Since SLC2A9 is a transporter, gene variants may be expected to associate more closely with the fractional excretion of urate, a measure of renal tubular transport, than with serum uric acid, which is influenced by production and extrarenal clearance. Methods. Genotypes of single nucleotide polymorphisms (SNPs) distributed across the SLC2A9 gene were obtained in the Genetic Epidemiology Network of Arteriopathy cohorts. The associations of SNPs with serum uric acid, fractional excretion of urate and urine urate-to-creatinine ratio were assessed with adjustments for age, sex, diuretic use, BMI, homocysteine and triglycerides. Results. We identified SLC2A9 gene variants that were associated with serum uric acid in 1155 African American subjects (53 SNPs) and 1132 white subjects (63 SNPs). The most statistically significant SNPs in African American subjects (rs13113918) and white subjects (rs11723439) were in the latter half of the gene and explained 2.7 and 2.8% of the variation in serum uric acid, respectively. After adjustment for this SNP in African Americans, 0.9% of the variation in serum uric acid was explained by an SNP (rs1568318) in the first half of the gene. Unexpectedly, SLC2A9 gene variants had stronger associations with serum uric acid than with fractional excretion of urate. Conclusions. These findings support two different loci by which SLC2A9 variants affect uric acid levels in African Americans and suggest SLC2A9 variants affect serum uric acid level via renal and extrarenal clearance.
Investigation of common fluorophores for the detection of nitrated explosives by fluorescence quenching

Previous studies have indicated that nitrated explosives may be detected by fluorescence quenching of pyrene and related compounds. The use of pyrene, however, invokes numerous health and waste disposal hazards. In the present study, ten safer fluorophores are identified for quenching detection of target nitrated compounds. Initially, Stern-Volmer constants are measured for each fluorophore with nitrobenzene and 4-nitrotoluene to determine the sensitivity of the quenching interaction. For quenching constants greater than 50 M(-1), sensitivity and selectivity are investigated further using an extended set of target quenchers. Nitromethane, nitrobenzene, 4-nitrotoluene, and 2,6-dinitrotoluene are chosen to represent nitrated explosives and their degradation products; aniline, benzoic acid, and phenol are chosen to represent potential interfering compounds. Among the fluorophores investigated, purpurin, malachite green, and phenol red demonstrate the greatest sensitivity and selectivity for nitrated compounds. Correlation of the quenching rate constants for these fluorophores to Rehm-Weller theory suggests an electron-transfer quenching mechanism. As a result of the large quenching constants, purpurin, malachite green, and phenol red are the most promising for future detection of nitrated explosives via fluorescence quenching.
Personal information management practices of teachers

Teaching is an information-rich profession with increasing demands on accountability and performance. Ideally, a well-managed information space provides teachers with relevant information when they need it, thus increasing their efficiency and efficacy and conceivably improving teaching quality. Little is known about teacher personal information management (PIM). This exploratory study employed interviews to establish a context to study teacher PIM. The study found that teachers draw information from a variety of physical and digital sources, and while they were aware of sources that had valuable information, especially digital libraries and their school library media centers, they rarely used them. Teachers used distinctive personal organization schemes to manage their information, sorting information alphabetically, topically, and by educational standards. This study introduced the observed phenomenon of “information heritage,” where teachers were handed down information from their predecessors and then had to choose what to do with it and how to incorporate it into their PIM practices. Teachers store their information physically in cabinets, closets, and shelves, and digitally on their computer hard drives, school group drives, and using bookmarks. Ephemeral information created by teachers often has time management purposes.
Microclump effects in magnetically-immersed electron diodes

Summary form only given. Magnetically-immersed electron diodes are being developed to produce needle-like, high-current, electron beams for radiography applications. An immersed diode consists of a needle cathode and a planar anode/bremmstrahlung converter which are both immersed in a strong solenoidal magnetic field (12-50 T); nominal parameters are 10 MV, 40 kA, 0.5 mm radius cathode, and 5-35 cm anode-cathode gaps. A physical picture of normal and abnormal diode behavior is emerging. Normal diode behavior occurs for times 0/spl les/t/spl les//spl tau/, where the transition time /spl tau/ is typically 30 ns; during this time, bipolar space-charge limited flow occurs, which scales well to desired radiography parameters of high dose and small spot size. Abnormal diode behavior occurs for t/spl ges//spl tau/, which results in substantial increases in spot size and current (impedance reduction). This abnormal behavior appears to be caused by an increase in ion charge in the gap, which may result from poor vacuum, impurity ions undergoing ion-ion stripping collisions during transit, or microclumps undergoing stripping collisions during transit. The potential effects of microclumps on diode behavior are reported here.
Learning style preferences and course performance in an undergraduate physiology class

Learning styles may be classified according to the sensory modality that one most prefers to use when internalizing information. The four major sensory modalities are visual, aural or auditory, rea...
State constraints in the linear regulator problem: a case study

An optimal control problem for a double integrator with state constraints is considered. By appropriately approximating the constraints we reduce the problem to a convex finite dimensional optimization problem. >
Behavioral problems in stroke rehabilitation patients: A prospective pilot study

Thirty-two patients undergoing rehabilitation after stroke were prospectively evaluated in a pilot study to determine the frequency and significance of behavioral problems interfering with rehabilitation. Based on prior experience within the rehabilitation unit, we studied depression, as well as somnolence, irritability, anxiety, confusion, delusions, denial of deficit, impulsivity, inappropriate sexual behavior, and pain. Depression was present in 31% of patients, and other behavioral problems occurred in up to 41% of patients. Although the sample size was small, significant associations were noted between somnolence and left hemisphere infarct, between the number of behavioral problems and rehabilitation outcome, and between certain behavioral problems and neurologic variables. Behavioral problems other than depression are common after stroke, and such problems correlate with specific neurologic variables. Rehabilitation outcome can be hindered by these identified behavior problems.
Emerging biological observations in prostate cancer.

Emerging biological observations in prostate cancer provide the opportunity for the development of novel approaches to prevention, detection and treatment. Two observations selected for discussion in this review revolve around the mechanisms of action of signaling through the androgen receptor (AR) and the TMPRSS2:ERG chromosomal rearrangement, a fusion protein seen in nearly 50% of prostate cancers. Despite being called androgen-independent, these prostate cancers continue to depend on AR signaling despite low serum androgen levels. AR reactivation in recurrent tumors is hypothesized to occur through multiple mechanisms: AR amplification, AR mutation, active AR signaling (despite low levels of androgen), AR coactivators, ligand-independent AR activation, enhanced local production of androgens, alternative sources of androgen and upregulation in antiapoptotic genes in prostate cancer cells. A major breakthrough in prostate cancer was the identification of recurrent fusions between the androgen-regulated g...
Reliability-Constrained Optimum Placement of Reclosers and Distributed Generators in Distribution Networks Using an Ant Colony System Algorithm

Optimal placement of protection devices and distributed generators (DGs) in radial feeders is important to ensure power system reliability. Distributed generation is being adopted in distribution networks with one of the objectives being enhancement of system reliability. In this paper, an ant colony system algorithm is used to derive the optimal recloser and DG placement scheme for radial distribution networks. A composite reliability index is used as the objective function in the optimization procedure. Simulations are carried out based on two practical distribution systems to validate the effectiveness of the proposed method. Furthermore, comparative studies in relation to genetic algorithm are also conducted.