Radiation-induced damage in GaAs particle detectors

The motivation for investigating the use of GaAs as a material for detecting particles in experiments for high-energy physics (HEP) arose from its perceived resistance to radiation damage. This is a vital requirement for detector materials that are to be used in experiments at future accelerators where the radiation environments would exclude all but the most radiation resistant of detector types     

The inactivation kinetics of H-1 parvovirus by chlorine

A newly isolated enteric virus has recently been found to be associated with large outbreaks of waterborne gastroenteritis. Most commonly referred to as the Norwalk agent, this virus appears to be morphologically and biophysically similar to the parvoviruses. In this study the parvovirus H-1, a putative human virus containing single-stranded DNA, was used as a model virus for chlorine inactivation experiments. The objective of this research was to investigate the kinetics of inactivation of this virus by low levels of free chlorine (0.05–0.20 mgl⁻¹) at pH 7 and at 5, 10, 20 and 30°C.Inactivation occurred in the usual dose-response relationship, that is, increasing the chlorine dose caused an increase in the rate of inactivation. The energy required for the inactivation reaction using 0.05 mgl⁻¹ free chlorine from 5 to 30°C was graphically determined to be 2.4 kcal mol⁻¹. The change in entropy was calculated to be -52.34 entropy units. For disinfection purposes, the time required for 99% inactivation of H-1 parvovirus at pH 7.20°C and a chlorine dose of 0.2 mgl⁻¹ free chlorine was 3.2 min. The parvovirus H-1 appeared to be less resistant to free chlorine than poliovirus type 1 (LSc).     

Shock Tube Measurements of the Equation of State of Argon

We have investigated the equation of state of argon at elevated temperatures and pressures using a new shock tube method. Temperatures in the range of 1280 to 1830 K, and pressures from 6 to 50 MPa were generated behind reflected shock waves in test gas mixtures of argon with trace amounts of CO and H₂ added. Density was determined from reflected shock pressure and incident shock speed measurements using the shock-jump relations. Temperature was determined from the modeling of the 4.7 sum infrared emission of the fundamental vibrational band of thermally-equilibrated CO. The experimentally determined argon P-p-T data points are in good agreement with the static-cell data of LeCocq and an extrapolation of the equation of state of Stewart and Jacobsen.     

Personality€nvironment constellations and alcohol use: A process-oriented study of intraindividual change during adolescence.

Tested the salience of documented risk and protective factors in contributing to intra-individual changes in alcohol use behaviors and negative consequences of use during adolescence within an interactionist and process-oriented perspective. 870 Ss from a longitudinal study of normal adolescent development completed self-report questionnaires. Ss were 12 or 15 yrs old at the 1st test and were retested twice at 3-yr intervals (92% longitudinal retest rate). Person–environment constellations comprising high impulsivity, disinhibition, and deviant peer group associations, and to a lesser extent, low parental control, most strongly influenced high-risk developmental trajectories of use intensity and problems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A computer-controlled research ventilator for small animals: designand evaluation

The understanding of the mechanical properties of the mammalian respiratory system and how they change under the influence of drugs and in disease are frequently pursued in small animals, since they can be easily obtained in large numbers as pure-bred strains. However, conventional experimental set-ups for studying small animals are generally limited in their ability to measure gas flow into the lungs. Here, the authors present a computer-controlled research ventilator for small animals which can provide conventional mechanical ventilation as well as arbitrary flow perturbations with a bandwidth from 0-55 Hz. Respiratory impedance is estimated from the displacement of the piston and the pressure it generates, thereby obviating the need for a direct flow measurement. The performance of the device was tested on mechanical loads whose impedances were calculated theoretically. The measured and predicted loads agreed within less than 5% up to 30 Hz. Furthermore, the measured impedance of two mechanical loads in series precisely matched the sum of their individual impedances     

Social information-processing patterns partially mediate the effect of early physical abuse on later conduct problems.

The authors tested the hypothesis that early physical abuse is associated with later externalizing behavior outcomes and that this relation is mediated by the intervening development of biased social information-processing patterns. They assessed 584 randomly selected boys and girls from European American and African American backgrounds for the lifetime experience of physical abuse through clinical interviews with mothers prior to the child's matriculation in kindergarten. Early abuse increased the risk of teacher-rated externalizing outcomes in Grades 3 and 4 by fourfold, and this effect could not be accounted for by confounded ecological or child factors. Abuse was associated with later processing patterns (encoding errors, hostile attributional biases, accessing of aggressive responses, and positive evaluations of aggression), which, in turn, predicted later externalizing outcomes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A nonstatistical approach to estimating confidence intervals aboutmodel parameters: application to respiratory mechanics

Estimates of parameters obtained by fitting models to physiologic data are of little use unless accompanied by confidence intervals. The standard methods for estimating confidence intervals are statistical, and make the assumption that the fitted model accounts for all the deterministic variation in the data while the residuals between the fitted model and the data reflect only stochastic noise. In practice, this is frequently not the case, as one often finds the residuals to be systematically distributed about zero. In this paper, we develop an approach for assessing confidence in a parameter estimate when the order of the model is clearly less than that of the system being modeled. Our approach does not require a parameter to have a single value located within a region of confidence. Instead, we let the parameter value vary over the data set in such a way as to provide a good fit to the entire data set. We apply our approach to the estimation of the resistance of the respiratory system in which a simple model is fitted to measurements of tracheal pressure and flow by recursive multiple linear regression. The values of resistance required to achieve a good fit are represented as a modified histogram in which the contribution of a particular resistance value to the histogram is weighted by the amount of information used in its determination. Our approach provides parameter frequency distribution functions that convey the degree of confidence one may have in the parameter, while not being based on erroneous statistical assumptions.