cssi/SciSciGPT-SciSciNet huggingface dataset:
Should control theory be used for economic stabilization

Abstract In a genetic-historical view of the fundamental revolution in outlook which represents the real beginning of modern natural science was the discovery that the inert objects of nature are not like men, i.e., subject to persuasion, exhortation, coercion, deception, etc., but are “inexorable.” The position which we have to combat seems to rest upon an inference, characteristically drawn by the “best minds” of our race, that since natural objects are not like men, men must be like natural objects (Knight, 1941, p. 121).
The validity of using a quasi-steady state approximation for the reversible Michaelis-Menten mechanism of enzyme action.

For most enzyme-catalyzed mechanisms there is an error introduced when one uses the quasi-steady state approximation. For k 1 > k −2 in scheme I a maximum value for this error is 4/27 of the ratio of the total concentration of enzyme active centers divided by the instantaneous substrate concentration remaining when the experimental data is collected. For k 1 k −2 in scheme I the maximum value for this error is amplified by the ratio of k −2 / k 1 .
Infection of HIV-specific CD4 T helper cells and the clonal composition of the response.

Abstract A hallmark of human immunodeficiency virus is its ability to infect CD4+ T helper cells, thus impairing helper cell responses and consequently effector responses whose maintenance depends on help (such as killer T cells and B cells). In particular, the virus has been shown to infect HIV-specific helper cells preferentially. Using mathematical models, we investigate the consequence of this assumption for the basic dynamics between HIV and its target cells, assuming the existence of two independently regulated helper cell clones, directed against different epitopes of the virus. In contrast to previous studies, we examine a relatively simple scenario, only concentrating on the interactions between the virus and its target cells, not taking into account any helper-dependent effector responses. Further, there is no direct competition for space or antigenic stimulation in the model. Yet, a set of interesting outcomes is observed that provide further insights into factors that shape helper cell responses. Despite the absence of competition, a stronger helper cell clone can still exclude a weaker one because the two clones are infected by the same pathogen, an ecological concept called “apparent competition”. Moreover, we also observe “facilitation”: if one of the helper cell clones is too weak to become established in isolation, the presence of a stronger clone can provide enhanced antigenic stimulation, thus allowing the weaker clone to persist. The dependencies of these outcomes on parameters is explored. Factors that reduce viral infectivity and increase the death rate of infected cells promote coexistence, which is in agreement with the observation that stronger immunity correlates with broader helper cell responses. The basic model is extended to explicitly take into account helper-dependent CTL responses and direct competition. This study sheds further light onto the factors that can influence the clonal composition of HIV-specific helper cell responses, which has implications for the overall pattern of disease progression.
Small amplitude vibration compensation for precision diamond turning

Abstract The inherent vibration in a precision diamond turning machine at the natural frequency of the slide cannot be compensated for by the slide drive. In order to provide in-process error correction a higher bandwidth actuator such as a tool servo proved to be an efficient way to prevent these vibrations of the machine from being transferred into the surface of diamond turned parts. This study investigates the sources of small amplitude vibration errors that are translated into the precision finished parts and proposes an efficient method of eliminating those types of errors. The error correction process includes real time monitoring and compensation of the disturbances that improves the final surface quality. This method could theoretically be useful in correcting less precise machines for use as precision finishing machines.
Taylor stability of a thermoviscoelastic fluid in couette flow

Abstract Taylor stability in Couette flow of a thermoviscoelastic fluid between two rotating coaxial circular cylinders is investigated employing the constitutive theory of Eringen and Koh. The stability problem is reduced to a characteristic value problem which is solved to obtain stability criteria in terms of critical Values of Taylor numbers. The results are compared with those of the classical viscous fluids and viscoinelastic fluids and the stabilizing effects of the thermoviscoelastic nature of the fluid are discussed.
New Methodology for Crevice-Corrosion Testing of Welds with Reinforcements

Abstract Weld zones in fabricated structures may exhibit preferential corrosion, especially under crevice-corrosion conditions. However, it is difficult to produce crevice conditions in the laboratory because of the nonflat surfaces associated with weld reinforcements. A new methodology has been developed for testing welds with this common geometry. Its application has proven successful in evaluating the effects of weld material, surface condition, and temperature on the crevice-corrosion characteristics of weld zones with reinforcements.
The Impacts of Social Capital on Infant Mortality in the U.S.: A Spatial Investigation

One of the leading health mysteries in the U.S. is why the infant mortality rate is one of the highest among industrialized countries. Although the relationships of both maternal health and socioeconomic characteristics to infant mortality rates are well documented, little is known about whether the social environment is associated with infant health. Moreover, few ecological studies of infant mortality in the literature have adopted a spatial approach to handle the spatial dependence embedded in the data. This study is designed to fill these gaps by connecting the concept of social capital with infant mortality in the U.S. at the county level. In so doing, it employs a spatial Poisson methodology to manage spatial dependence. The major conclusions are: (1) Though structural social capital index alone is predictive of infant health, this effect disappears when residential stability and neighborhood safety (cognitive social capital) are considered. Both could better explain why infant mortality varies by county. (2) The adverse effect of low birth weight on infant health could be attenuated by social capital and other socioeconomic conditions. (3) Our study illustrates that a spatial approach is necessary, especially for ecological studies; otherwise, spatial dependence would lead to biased estimates and incorrect conclusions.
Inhibition of Fried Meat-Induced Colorectal DNA Damage and Altered Systemic Genotoxicity in Humans by Crucifera, Chlorophyllin, and Yogurt

Dietary exposures implicated as reducing or causing risk for colorectal cancer may reduce or cause DNA damage in colon tissue; however, no one has assessed this hypothesis directly in humans. Thus, we enrolled 16 healthy volunteers in a 4-week controlled feeding study where 8 subjects were randomly assigned to dietary regimens containing meat cooked at either low (100°C) or high temperature (250°C), each for 2 weeks in a crossover design. The other 8 subjects were randomly assigned to dietary regimens containing the high-temperature meat diet alone or in combination with 3 putative mutagen inhibitors: cruciferous vegetables, yogurt, and chlorophyllin tablets, also in a crossover design. Subjects were nonsmokers, at least 18 years old, and not currently taking prescription drugs or antibiotics. We used the Salmonella assay to analyze the meat, urine, and feces for mutagenicity, and the comet assay to analyze rectal biopsies and peripheral blood lymphocytes for DNA damage. Low-temperature meat had undetectable levels of heterocyclic amines (HCAs) and was not mutagenic, whereas high-temperature meat had high HCA levels and was highly mutagenic. The high-temperature meat diet increased the mutagenicity of hydrolyzed urine and feces compared to the low-temperature meat diet. The mutagenicity of hydrolyzed urine was increased nearly twofold by the inhibitor diet, indicating that the inhibitors enhanced conjugation. Inhibitors decreased significantly the mutagenicity of un-hydrolyzed and hydrolyzed feces. The diets did not alter the levels of DNA damage in non-target white blood cells, but the inhibitor diet decreased nearly twofold the DNA damage in target colorectal cells. To our knowledge, this is the first demonstration that dietary factors can reduce DNA damage in the target tissue of fried-meat associated carcinogenesis.
Hydrogen as a migrating group in some pinacol ­rearrangements: a DFT study

DFT calculations at the Becke3LYP/6–31G* level were employed to demonstrate that the pinacol rearrangement of ethylene glycol and the 1,1-dimethyl and 1,1,2-trimethyl analogs undergo pinacol rearrangements by a concerted hydrogen-bridged transition structure. No evidence for a bridged intermediate was found. Calculations by two methods on the ethylene glycol system were repeated with the various structures embedded in a solvent cavity with the medium dielectric constant set for water. The ratio of rates for the two methylated glycols was calculated with good agreement with the experimental value. The kinetic isotope effect for the rearrangement of 1,1,2-trimethylethylene glycol was calculated (2.8) in fair agreement with the experimental value of 1.6. Sources of error are briefly discussed. Copyright © 1999 John Wiley & Sons, Ltd.
Enduring Lessons and Opportunities Lost from the San Fernando Earthquake of February 9, 1971

Twenty-five years have passed since the San Fernando earthquake of February 9, 1971. The paper reviews the lessons learned and not learned from this notable event. Most of the major lessons were reported within a few weeks of the earthquake by a panel appointed by the National Academies of Sciences and of Engineering. In this paper, the status of each of the eighteen general lessons cited by the panel is reviewed, plus two additional lessons selected from other studies of the earthquake. The lessons learned ranged broadly and concerned measures needed to reduce future earthquake hazards, as well as recommended scientific and engineering efforts. Although all of the lessons learned were not heeded, the San Fernando earthquake represented a turning point in public awareness and in actions taken to reduce earthquake hazard. Recent earthquakes have shown, however, that much remains to be done.
Evolving concepts in the management of hypertension

Currently, a plethora of antihypertensive medications exists. One concern about the long-term use of many of these agents is that adverse effects may offset their benefits. Despite the availability of many newer agents, blood pressure continues to be inadequately controlled in the majority of treated hypertensive patients, and many still remain at higher risk of premature death than the general population. More than 60% of treated hypertensive patients fail to attain blood pressures of < 140/90 mmHg. The major factors that permit a rational choice of medication include demographic considerations such as race and age, coexisting diseases, safety, patient acceptance (quality of life), potential drug interactions, and additional salutary effects. The role of nondiuretic monotherapy is an integral component of this discussion. Preliminary data indicate that the use of calcium-channel blockers, converting-enzyme inhibitors, and All-receptor antagonists constitutes excellent therapy in many patients. The effects of medication on the metabolic and lipid profiles are also considered.
Effects of Anesthetics on the Response of Submaxillary and Pancreatic Glands to Prostigmine and Physostigmine

Summary and ConclusionsProstigmine and physostigmine were administered intravenously in doses ranging from 0.005 mg to 0.2 mg per kilo to dogs anesthetized with either sodium pentobarbital, chloralose, or paraldehyde. The effects on pancreatic and salivary secretion and on the blood pressure and heart rate were recorded.1. In the lower doses prostigmine is a more potent excitant of pancreatic and submaxillary secretion than physostigmine. A “reversal” in the response of the pancreas occurred when the dose of prostigmine was increased above 0.06 mg per kilo, and of the submaxillary gland in doses above 0.1 mg per kilo.2. Chloralose anesthesia markedly diminishes the secretory response of the pancreas and submaxillary secretion to prostigmine and physostigmine; the same is true of paraldehyde anesthesia.
Comparison of μ2‐scaled Hückel theory and Hartree–Fock theory of boranes and carboranes

The μ2‐scaled Huckel method is used to calculate the electronic energy surfaces of the four boranes BnH2−n (n=8–11) and the carborane C2B8H2−10. These electronic energy surfaces and their minimum energy geometries are directly compared to both the single crystal x‐ray determined structures and to Hartree–Fock optimized geometries. Bond distances differ on the average by 0.04 A between alternate methods. It is shown that μ2‐scaled Huckel results may be directly interpreted by analysis of the highest occupied and lowest unoccupied molecular orbitals. Also studied by the μ2‐scaled Huckel and Hartree–Fock methods are the isomerization pathways of B8H2−8, B11H2−11, and C2B8H2−10. Reaction barriers and transition state geometries found by the two different calculational methods are in fair agreement with each other and known literature values. Using the μ2‐scaled Huckel method one can readily deduce that the B8H2−8 and B11H2−11 isomerizations are Woodward–Hoffmann allowed reactions. In the case of B8H2−8 this allowed mechanism is contrasted to an alternate Woodward–Hoffmann forbidden pathway. Hartree–Fock calculations on the C2B8H2−10 confirm earlier μ2‐scaled Huckel based findings, that a second less stable isomer of C2B8H2−10 exists which, in contradiction to Wade’s rules of electron deficient clusters, has a pair of open square faces in the cluster.
Temperature Distribution in Two-Layered Composites

The thermal wave propagation behavior within a two-layered anisotropic substrate is investigated in this study using a two-dimensional hyperbolic heat conduction model. The governing equations are solved by a flux splitting algorithm based on the Godunov numerical scheme. Special attention is given to the nature of heat propagation and reflection within the composite substrate after an instantaneous release of energy. The influences of the thermal lagging behavior, anisotropic thermal conductivity, and material interfacial effect on temperature distributions are investigated. Comparisons are made between results obtained by the thermal diffusion and wave models.Copyright © 2003 by ASME
TGFβ-Inducible Early Gene (TIEG) Also Codes for Early Growth Response α (EGRα): Evidence of Multiple Transcripts from Alternate Promoters ☆

Abstract TGFβ-inducible early gene (TIEG) and early growth response α (EGRα) are putative transcription factors based on homology to known zinc finger proteins SP1, EGR1, BTEB, and Wilm tumor. Here we report that TIEG and EGRα are expressed from alternative promoters of the same gene. The TIEG/EGRα gene spans 8 kb and contains five exons. Use of alternative first exons results in TIEG having 12 unique amino acids on its N-terminus. Computer analysis of the 5′ upstream regions of either TIEG (exon 1a) or EGRα (exon 1b) does not identify a TATA box or initiator sequencebut shows consensus sequence similarities to binding sites for several transcription factors including SP1,JunB, and aromatic hydrocarbon/receptor–ligand complexes. Analysis of constructs containing 5′-flanking regions show that both the TIEG and the EGRα promoters have significant activity in human fetal osteoblast cells. Northern analysis of mRNA from various human tissues and several cell lines reveals that TIEG is the predominant transcript produced and regulated by growth factors from the TIEG/EGRα gene.
Optimization of simulation responses in a multicomputing environment

This paper describes the application of experimental design techniques to computer simulation in a multicomputing environment. Three principal areas of experimental design are considered: (1) factor screening experiments; (2) experiments of comparison; and (3) response surface methodology.
Structural Relaxation and Structural Memory at Amorphous Silicon Dangling Bonds

We examine the energy and time scales of configurational relaxation around the dangling bond defect, D, in hydrogenated Amorphous silicon (a-Si:H). After D captures or emits charge, its bond angle, electron energy eigenvalues and local structural environment all change. This determines the measured electronic energy levels; we use previous theoretical results and experimental data to estimate the density of gap states in the different atomic configurations of D. We also describe D relaxation effects observed in experiments, including the very slow relaxations found in recent transient capacitance measurements. To explain the unusual T-independent kinetics of transient capacitance carrier emission, we propose a model of “structural memory” in a-Si:H. After carrier capture, neighbors of D retain memory of their pre-capture configuration for seconds at 300K. The rate-limiting step to carrier emission is an effectively one-dimensional random walk of these neighbors through their configuration space and back to the pre-capture configuration. The final, activated, step of emission is very rapid. We describe analytic and monte Carlo calculations that support the structural memory Model and propose possible microscopic Mechanisms.
Immigration Reform, Homeland Defense, and Metropolitan Economies in the Post 9-11 Environment

(2002). Immigration Reform, Homeland Defense, and Metropolitan Economies in the Post 9-11 Environment. Urban Geography: Vol. 23, No. 3, pp. 201-212.
Zoning in minnesota; eminent domain vs. police power

The development of zoning law in Minnesota is a cross section of the history of zoning in the United States
Delooping classifying spaces in algebraic K-theory

FOR ANY associative ring with identity A let BGL(A)+ denote the “classifying space” for algebraic K-theory given in [I51 where a definition for the higher K-theory functors Ki, i >, 1, is proposed by Quillen as K,(A) = n,(BGL(A)+). This K, and KZ agree with the K, of Bass [2] and the K2 of Milnor [ 141 and the theory has other very pleasant properties [ 151. Now Anderson [l] and Segal [17] have shown how to associate a generalized cohomology theory K’(X; q) to any category %? with a “commutative” and “associative” internal operation ?? x %’ -+ e. If one takes the category 9’ of finitely generated projective modules over A with morphisms the isomorphisms and internal operation the direct sum, then K,(A) = K-‘(pt; 9’) for i 2 0. See [18]. Our purpose here is to show that
The association of pre-existing left atrial fibrosis with clinical variables in patients referred for catheter ablation of atrial fibrillation.

Introduction: Atrial fibrillation (AF) recurrence after ablation is associated with left atrial (LA) fibrosis on late gadolinium enhanced (LGE) magnetic resonance imaging (MRI). We sought to determine pre-ablation, clinical characteristics that associate with the extent of LA fibrosis in patients undergoing catheter ablation for AF. Methods and results: Consecutive patients presenting for catheter ablation of AF were enrolled and underwent LGE-MRI prior to initial AF ablation. The extent of fibrosis as a percentage of total LA myocardium was calculated in all patients prior to ablation. The cohort was divided into quartiles based on the percentage of fibrosis. Of 60 patients enrolled in the cohort, 13 had ,5% fibrosis (Group 1), 15 had 5–7% fibrosis (Group 2), 17 had 8–13% fibrosis (Group 3), and 15 had 14–36% fibrosis (Group 4). The extent of LA fibrosis was positively associated with time in continuous AF, and the presence of persistent or longstanding persistent AF. However, no statistically significant difference was observed in the presence of comorbid conditions, age, BMI, LA volume, or family history of AF among the four groups. After adjusting for diabetes and hypertension in a multivariable linear regression model, paroxysmal AF remained independently and negatively associated with the extent of fibrosis (-4.0 ± 1.8, P = 0.034). Conclusion: The extent of LA fibrosis in patients undergoing AF ablation is associated with AF type and time in continuous AF. Our results suggest that the presence and duration of AF are primary determinants of increased atrial LGE.
Blocking O-Linked GlcNAc Cycling in Drosophila Insulin-producing Cells Perturbs Glucose-Insulin Homeostasis

A dynamic cycle of O-linked GlcNAc (O-GlcNAc) addition and removal is catalyzed by O-GlcNAc transferase and O-GlcNAcase, respectively, in a process that serves as the final step in a nutrient-driven "hexosamine-signaling pathway." Evidence points to a role for O-GlcNAc cycling in diabetes and insulin resistance. We have used Drosophila melanogaster to determine whether O-GlcNAc metabolism plays a role in modulating Drosophila insulin-like peptide (dilp) production and insulin signaling. We employed transgenesis to either overexpress or knock down Drosophila Ogt(sxc) and Oga in insulin-producing cells (IPCs) or fat bodies using the GAL4-UAS system. Knockdown of Ogt decreased Dilp2, Dilp3, and Dilp5 production, with reduced body size and decreased phosphorylation of Akt in vivo. In contrast, knockdown of Oga increased Dilp2, Dilp3, and Dilp5 production, increased body size, and enhanced phosphorylation of Akt in vivo. However, knockdown of either Ogt(sxc) or Oga in the IPCs increased the hemolymph carbohydrate concentration. Furthermore, phosphorylation of Akt stimulated by extraneous insulin in an ex vivo cultured fat body of third instar larvae was diminished in strains subjected to IPC knockdown of Ogt or Oga. Knockdown of O-GlcNAc cycling enzymes in the fat body dramatically reduced neutral lipid stores. These results demonstrate that altered O-GlcNAc cycling in Drosophila IPCs modulates insulin production and influences the insulin responsiveness of peripheral tissues. The observed phenotypes in O-GlcNAc cycling mimic pancreatic β-cell dysfunction and glucose toxicity related to sustained hyperglycemia in mammals.
Ultrastructural aging of the RPE-Bruch's membrane-choriocapillaris complex in the D-galactose-treated mouse.

PURPOSE. Low-dose D-galactose treatment in mice induces accelerated aging due to advanced glycation endproduct (AGEs) formation. The purpose of this study was to identify ultrastructural aging in the retinal pigment epithelium (RPE)-Bruch's membrane- choriocapillaris. METHODS. Five-month-old C57B16 mice were injected daily with D-galactose or control buffer for 8 weeks. Eighteen-month-old mice were also treated with control buffer for 8 weeks. Eyes were prepared for electron microscopy and AGE-specific fluorescence at ex = 370 nm/em = 440 nm and ex = 330 nm/ex = 390 nm. RESULTS. D-Galactose treatment induced AGE-specific fluorescence in lens and RPE/choroid compared to buffer-treated controls. In D-galactose-treated animals, the RPE had dilated and fewer basolateral infoldings. Bruch's membrane had alterations that included significant thickening, sub-RPE and prominent outer collagenous layer deposits, and choriocapillaris basement membrane duplication/splitting and thickening. The choriocapillaris endothelium displayed fenestration loss. CONCLUSIONS. Ultrastructural aging to the RPE-Bruch's membrane- choriocapillaris developed in mice treated with low-dose D-galactose. These changes could contribute to age-related changes that promote early age-related disease.
Predicting 3D spatial temperature uniformity in food storage systems from inlet temperature distribution

Abstract A temperature uniformity index (UI) was used to quantify the spatial homogeneity of temperature in a ventilated airspace (3 m × 2 m × 1.5 m) by using a 3D-grid of temperature sensors. An airflow pattern sensor, developed to control airflow pattern in ventilated buildings, was used to predict UI in the room at different conditions. The objective of this study was to investigate the relation between the 2D inlet temperature distribution measured by the airflow pattern sensor and 3D uniformity index in the room for different ventilation rates and inlet flap positions in a room filled with empty or potato filled crates. Regression analysis was used to model the UI from the temperature measurements obtained from the airflow pattern sensor. Using 10 temperature sensors on the airflow pattern sensor, R 2 -values of 0.81 and 0.73 were found with an average standard error of 5 and 7% for UI from 15 to 96%, in a room filled with empty or potato filled crates, respectively. Results showed that 2D inlet temperature measurements can be used to predict 3D uniformity of temperature in a mechanically ventilated space.
Subellular distribution of S-adenosylamenthionine decarboxylase in rat liver. Evidence of decarboxylation of S-adenosylmenthionine separate from synthesis of spermidine

Abstract The acitivity of S -adenosylmethionine decarboxylase in rat liver homogenates is localized chiefly in the crude nuclear fraction, probably associated with membrane fragments, with the remainder in the supernatant fraction. This distribution is not paralleled by the activity of the cytoplasmic enzyme, lactate dehydrogenase. The spermidine-synthesizing activity of whole homogenate is recovered entirely in the supernatant fraction. Measurement of various kinetic parameters in crude fractions provided no positive evidence for isozymes of S -adenosylmethionine decarboxylase. Some species do not possess a sedimentable fraction of S -adenosylmethionine decarboxylase activity in liver. In those species all activity present in the whole homogenate of liver is released into the supernatant fraction.
Graves' hyperthyroidism is antibody-mediated but is predominantly a Th1-type cytokine disease.

We wish to comment on an assumption commonly made that Graves' disease and Hashimoto's thyroiditis are distinguished by immune responses involving T-cell helper type 1 and type 2 (Th1 and Th2), respectively. For example, the title of a paper recently published in the JCEM refers to this perceived Th1/Th2 dichotomy in thyroid autoimmune disorders (1). In the abstract, Marique et al (1) state that “Hashimoto's thyroiditis and Graves' disease are thyroid disorders driven by Th1 and Th2 responses, respectively,” and subsequently they state that Graves' disease “is driven by the humoral immune response and Th2 cytokines (IL-4 and IL-10)”. The authors are not alone in adopting this viewpoint which we, ourselves, did in earlier years. Subsequently, we (and possibly others) have been unsuccessful in convincing the thyroid community that these assumptions are incorrect. The purpose of this Commentary is to summarize key points of information in order to enhance insight into the pathogenesis of these complex, fascinating, and extremely common disorders.
Comparison of various technologies used for distribution transformers from an eco standpoint

This paper provides some elements of a life cycle analysis for distribution transformers manufactured in different technologies. The detailed study was made for three phase 2.6 MVA, 36 kV transformer commonly used in wind turbine application in three design options: dry-type cast resin, conventional liquid-immersed and compact liquid-immersed (such as commercially available SLIM® transformer). As a part of the study described in the paper, the methodology and tools were developed to analyze main activities in transformer manufacturing process and main components of transformer design responsible for eco-footprint. Comparative exploratory Life Cycle Impact Assessment was made. Rather significant difference was observed between cast resin transformer and liquid-immersed options. This was mainly related to the weight of transformer components. Resulting losses are also higher for cast resin transformer; hence the use phase of this type of design has more environmental impact, too. The conclusions may become a guideline for selection of transformer technology at procurement stage in case environmental aspects are to become more and more critical. (4 pages)
Recent developments in carbon nanotubes

Unique and interesting nanotube properties directly result from their special topologies. Intrinsic electronic and transport properties are only now starting to be understood and demonstrate a wide variety of geometrical structure-dependent behaviors. High-temperature Aharonov-Bohm oscillations have been observed and exceptionally high current densities have been attained. Nanotube transistors and flat panel displays have been demonstrated. These recent discoveries point towards important applications and new insights into nanotube properties.
Ir studies of disordered zincblende semiconductors III-V-II-VI alloys and GaAs-Ga 2/3 Se

This paper presents the ir reflectance spectra of several III-V — II-VI alloys, GaAs-ZnSe, GaP-ZnSe and GaAs-ZnS, and the III-V — III2 -VI3 system, GaAs-Ga2/3 Se. GaAs-ZnSe and GaP-ZnSe alloys each display two reflectivity peaks, where-as the GaAs-ZnS system displays a single feature. These behaviors are explained using a linear chain model which considers both mass and force constant differences and which assumes pairing of the III-V and II-VI constituents. The spectrum of Ga2 Se3 is dominated by disorder induced features associated with the vacancies. Alloying with GaAs reduces the number of vacancies and is accompanied by im-portant changes in both the intensity and shape of the spectral features.
On the distribution of a symmetric statistic from a mixed population

The density of a symmetric statistic T = g(X 1, X 2, …, Xn ), for a random sample from a mixed population with density f(x) = pf 1(x) + pf 2), is a binomial mixture of the densities of the statist.ics Tk = g(Xk1 , Xk2 , Xkn ), k = 0, 1, … n. where Xki 's are independent with density f 1(x) if i ≤ k and density f 2(x) if i > k. It is shown how to find the distributions of some important symmetric statistics like sample mean, sample variance, and order statistics by using Tk 's. The results are applied to normal and exponential mixtures.
Early Childhood Precursors and Adolescent Sequelae of Grade School Peer Rejection and Victimization

This study examined the early childhood precursors and adolescent outcomes associated with grade school peer rejection and victimization among children oversampled for aggressive-disruptive behaviors. A central goal was to better understand the common and unique developmental correlates associated with these two types of peer adversity. There were 754 participants (46% African American, 50% European American, 4% other; 58% male; average age=5.65 at kindergarten entry) followed into seventh grade. Six waves of data were included in structural models focused on three developmental periods. Parents and teachers rated aggressive behavior, emotion dysregulation, and internalizing problems in kindergarten and Grade 1 (Waves 1-2); peer sociometric nominations tracked "least liked" and victimization in Grades 2, 3, and 4 (Waves 3-5); and youth reported on social problems, depressed mood, school adjustment difficulties, and delinquent activities in early adolescence (Grade 7, Wave 6). Structural models revealed that early aggression and emotion dysregulation (but not internalizing behavior) made unique contributions to grade school peer rejection; only emotion dysregulation made unique contributions to grade school victimization. Early internalizing problems and grade school victimization uniquely predicted adolescent social problems and depressed mood. Early aggression and grade school peer rejection uniquely predicted adolescent school adjustment difficulties and delinquent activities. Aggression and emotion dysregulation at school entry increased risk for peer rejection and victimization, and these two types of peer adversity had distinct as well as shared risk and adjustment correlates. Results suggest that the emotional functioning and peer experiences of aggressive-disruptive children deserve further attention in developmental and clinical research.
X-ray scatter correction method for dedicated breast computed tomography.

Purpose: To improve image quality and accuracy in dedicated breast computed tomography (BCT) by removing the x-ray scatter signal included in the BCT projections. Methods: The previously characterized magnitude and distribution of x-ray scatter in BCT results in both cupping artifacts and reduction of contrast and accuracy in the reconstructions. In this study, an image processing method is proposed that estimates and subtracts the low-frequency x-ray scatter signal included in each BCT projection postacquisition and prereconstruction. The estimation of this signal is performed using simple additional hardware, one additional BCT projection acquisition with negligible radiation dose, and simple image processing software algorithms. The high frequency quantum noise due to the scatter signal is reduced using a noise filter postreconstruction. The dosimetric consequences and validity of the assumptions of this algorithm were determined using Monte Carlo simulations. The feasibility of this method was determined by imaging a breast phantom on a BCT clinical prototype and comparing the corrected reconstructions to the unprocessed reconstructions and to reconstructions obtained from fan-beam acquisitions as a reference standard. One-dimensional profiles of the reconstructions and objective image quality metrics were used to determine the impact of the algorithm. Results: The proposed additional acquisition results in negligiblemore » additional radiation dose to the imaged breast ({approx}0.4% of the standard BCT acquisition). The processed phantom reconstruction showed substantially reduced cupping artifacts, increased contrast between adipose and glandular tissue equivalents, higher voxel value accuracy, and no discernible blurring of high frequency features. Conclusions: The proposed scatter correction method for dedicated breast CT is feasible and can result in highly improved image quality. Further optimization and testing, especially with patient images, is necessary to characterize its impact on clinical performance.« less
Congenital and Developmental Abnormalities of the Cervical Spine Encountered in Athletes

Patients with congenital or developmental anomalies of the cervical spine are encouraged to be active and participate in sports for their overall health. This population has unique anatomic considerations that preclude standard participation guidelines from being relevant. A conscientious evaluation of these patients coupled with an understanding of consensus recommendations for participation in sporting activities should allow for their injury-free participation in sporting activities. After appropriate evaluation a subset of patients with Os odontoideum, Klippel–Feil syndrome, and Down syndrome can safely participate in sporting activities.
Predicting response to selection on a quantitative trait: a comparison between models for mixed-mating populations.

Two different theoretical frameworks have been developed to predict response to selection in a mixed mating population (in which reproduction occurs by a mixture of outcrossing and self-fertilization). The genotypic covariance model (GCM) and the structured linear model (SLM) rely on the same assumptions regarding quantitative trait inheritance, but use different genetic summary statistics. Here, we demonstrate the algebraic relationships between the various genetic metrics used in each theory. This is accomplished by reformulating the GCM in terms of the Wright-Kempthorne equation. We use stochastic simulations to investigate the relative accuracy of each theory for a range of selfing rates. The SLM is generally more accurate than the GCM, the most pronounced differences emerging in simulations with inbreeding depression for fitness. In fact, with strong inbreeding depression and high selfing rates, evolution can occur opposite the direction predicted by the GCM. The simulations also indicate that direct application of random mating models to partially selfing populations can produce very inaccurate predictions if quantitative trait loci exhibit dominance.
Experimental investigation of small helium clusters: magic numbers and the onset of condensation

Clusters of He atoms formed in a supersonic free jet expansion have been studied by electron-bombardment ionization and mass spectrometry. Distinct magic-number enhancements of ion intensity are observed for clusters of 7, 10, 14, and 30 atoms for both helium isotopes, and for 23 atoms of $^{4}\mathrm{He}$. Dramatic differences in the onset of cluster formation between the two isotopes may be related to the stability of $^{4}\mathrm{He}$ dimers.
Repeated measures of vocal fundamental frequency perturbation obtained using the Visi-Pitch.

Summary This article reports on a study of intrasubject variability for a measure of vocal fundamental frequency perturbation in a group of young, normal speakers. Measurements of relative average perturbation (RAP) obtained using a Visi-Pitch were examined for the vowels /a/, /i/, and /u/ produced by 25 women and 24 men on two occasions, ∼1 week apart. Important findings consisted of higher levels of RAP for women than men and greater variability of RAP over the time period studied for women than men. Conclusions include the need for additional normative data regarding the use of the Visi-Pitch for the purpose of examining jitter.
The extraction of laminar flow from certain Brownian motions

Using the concept of average velocity, we show that laminar flow can be extracted from Brownian motion. The flows studied are those around a flat, two dimensional plate on the molecular level. Flows of both water vapor and air are simulated.
Effect of acrolein and glutathione depleting agents on thioredoxin

Acrolein is a widespread environmental pollutant that reacts rapidly with nucleophiles, especially cellular thiols. In addition to glutathione (GSH), thioredoxin (Trx) and thioredoxin reductase (TR) contain thiol groups and may react with electrophiles. In the present study, A549 cells treated with 5-25 microM acrolein for 30 min lost cellular Trx activity in a dose-dependent fashion. Over 90% of Trx activity was lost at concentrations of 25 microM or greater. In contrast, Trx protein content, as assessed by western blotting, was not altered immediately after the 30 min acrolein treatment. Both Trx activity and protein levels increased 4h after the acrolein treatment. However, Trx activity remained below control levels at 24h. A similar dose-response relationship was seen with TR in A549 cells exposed to acrolein. There was, however, a rapid recovery of TR activity such that it attained normal levels by 4h after doses < or = 75 microM acrolein. Diethyl maleate (DEM), a common but not highly specific, agent used to deplete GSH, also inactivated Trx. A 2 h exposure of A549 cells to 1 mM DEM depleted cellular GSH by ~50% and diminished Trx activity by over 67%. Lower DEM doses (0.125 mM and 0.25 mM) for 1h had no significant effect on GSH but significantly decreased Trx activity 12 and 23%, respectively. Similar to immediately after acrolein exposure, DEM did not affect Trx protein levels. A Trx-1-GFP fusion protein was transfected into A549 cells. While the fusion protein was expressed, the Trx component was inactive by the insulin reducing assay. In summary, Trx and TR are inactivated by acrolein. In addition, the GSH depleting agent DEM inactivates Trx somewhat more effectively than it depletes GSH. The Trx-1-GFP fusion protein, while readily expressed, appears to have little or no activity, perhaps because the small size of Trx-1 (12 kDa) is affected by the larger GFP.
Implementing CC2001: a breadth-first introductory course for a just-in-time curriculum design

A first course in computer science that loosely follows the Computing Curricula 2001 report is described. This course blends theory and practice, highlights algorithm design, introduces a modest amount of imperative programming, and uses an Internet algorithmics theme to tie the topics together and keep the course both challenging and interesting to those with and without previous computing experience.
Composition of the Secondary Particles Produced in Nuclear Interactions at ~10 12 eV

Twenty-two proton, neutron, and alpha jets (${N}_{h}\ensuremath{\le}3$, $2\ifmmode\times\else\texttimes\fi{}{10}^{11} \mathrm{eV}lEl1.5\ifmmode\times\else\texttimes\fi{}{10}^{13} \mathrm{eV}$), found in a 22-liter emulsion stack flown for 13 h at an altitude of 116 000 feet, have been analyzed to identify the nature of the particles emitted in the extreme backward c.m. cone. Among 82 tracks analyzed, out of 149 tracks traced (total length of the secondaries traced was 20.4 m and 74 interactions were found), 53 secondaries were attributed to pions, 18 to kaons, 10 to protons, and one to a hyperon. The relative composition of the 82 secondaries has a dependence on the c.m. emission angle $\overline{\ensuremath{\theta}}$. For $\overline{\ensuremath{\theta}}\ensuremath{\ge}175\ifmmode^\circ\else\textdegree\fi{}$, there were $7 \ensuremath{\pi}$, $9 K$, $10 p$, and $1 Y$; for $\overline{\ensuremath{\theta}}l175\ifmmode^\circ\else\textdegree\fi{}$, there were $46 \ensuremath{\pi}$, $9 K$, and no baryons. A similar distinction existed for the average c.m. momenta $〈\overline{p}〉$ and the average transverse momenta $〈{p}_{t}〉$ in the extreme backward c.m. emission angle; $〈\overline{p}〉$ becomes large and $〈{p}_{t}〉$ becomes small. The baryons carried the average fraction 0.5\ifmmode\pm\else\textpm\fi{}0.2 of the total available energy in the c.m. system. Concerning the $\frac{K}{\ensuremath{\pi}}$ ratio, ${p}_{t}$ distribution, and $〈\overline{p}〉$ at $\ensuremath{\theta}l175\ifmmode^\circ\else\textdegree\fi{}$, the hydro-dynamical theory with a critical temperature $k{T}_{c}\ensuremath{\cong}{m}_{\ensuremath{\pi}}{c}^{2}$ predicts the correct behavior. In this region, the c.m. momentum distribution of pions fits the form $\mathrm{dN}\ensuremath{\propto}{\overline{p}}^{n}d\overline{p}$ with $n=\ensuremath{-}0.8\ifmmode\pm\else\textpm\fi{}0.4$. But for the extreme backward c.m. emission angle region, $\overline{\ensuremath{\theta}}\ensuremath{\ge}175\ifmmode^\circ\else\textdegree\fi{}$, the smallness of $〈{p}_{t}〉$ and concentration of kaons and baryons favor an interpretation in terms of the Heisenberg theory.
SPAL: a speedy packet lookup technique for high-performance routers

This work introduces and evaluates a technique for speedy packet lookups, called SPAL, in high-performance routers, realized by fragmenting the BGP routing table into subsets. Such a router contains multiple line cards (LCs), each of which is equipped with a forwarding engine (FE) to perform table lookups locally based on its forwarding table (which is a fragmented subset). The number of table entries in each FE drops as the number of LCs in a router grows. This reduction in the forwarding table size drastically lowers the amount of SRAM (e.g., L3 data cache) required in each LC to hold the trie constructed according to the matching algorithm. SPAL calls for caching the lookup result of a given IP address at its home LC (denoted by LC/sub ho/, using the LR-cache), such that the result can satisfy the lookup requests for the same address from not only LC/sub ho/ but also other LCs quickly, when the switching fabric for interconnecting LCs has a low latency. Lookup results obtained from remote LCs are also held in the LR-cache of a local LC. Our trace-driven simulation reveals that SPAL indeed leads to substantial improvement in mean lookup performance. SPAL may possibly shorten the worst-case lookup time (thanks to fewer memory accesses during longest-prefix matching search) when compared with a current router without partitioning the routing table. It takes no specific traffic into consideration when selecting the partitioning bits, promising good scalability and a small mean lookup time per packet.
DIFFERENTIAL REINFORCEMENT THEORY EXAMINED

It is argued that the attempts of Burgess and Akers and of Adams to formulate Sutherland's differential association theory in the language of operant conditioning theory fail to preserve Sutherland's interesting insights by reducing his theory to the mere claim that criminal behavior is operant conditioning behavior. Questions are then raised about the truth of even this claim. Some attention is also given to the question of the verification of both Sutherland's original theory and the operant Conditioning reformulations of it.
Self-assembly of microcapsules regulated via the repressilator signaling network.

One of the intriguing challenges in designing active matter is devising systems that not only self-organize, but also exhibit self-regulation. Inspired by biological regulatory networks, we design a collection of self-organizing, self-regulating microcapsules that move in response to self-generated chemical signals. Three microcapsules act as localized sources of distinct chemicals that diffuse through surrounding fluid. Production rates are modulated by the “repressilator” regulatory network motif: each chemical species represses the production of the next in a cycle. Depending on the maximum production rates and capsule separation distances, we show that immobile capsules either exhibit steady or oscillatory chemical production. We then consider movement of the microcapsules over the substrate, induced by gradients in surface energy due to adsorbed chemicals. We numerically simulate this advection–diffusion–reaction system with solid–fluid interactions by combining lattice Boltzmann, immersed boundary and finite difference methods, and thereby, construct systems where the three capsules spontaneously assemble to form a close-packed triad. Chemical oscillations are shown to be critical to this assembly. By adjusting parameters, the triad can either remain stationary or translate as a cohesive group. Stationary triads can also be made to “turn off”, producing chemicals at minimal rates after assembly. These findings provide design rules for creating synthetic material systems that encompass biomimetic feedback loops, which enable dynamic collective behavior.