Predicting hydrocarbon removal from thermally enhanced soil vapor extraction systems. 1. Laboratory studies.

Conventional soil vapor extraction (SVE) systems have a limited effectiveness at removing semi-volatile chemicals from soil. Raising chemical vapor pressures by heating soil in-situ can decrease remediation time and help remove semi-volatile chemicals that otherwise would not be removed by conventional SVE. The increased compound removal rate that results from use of thermally enhanced SVE was investigated in laboratory studies. Increased soil temperatures (50-150 degrees C) increased both the rate of removal of the compounds studied and the range of compounds that were removed in column studies. The column studies indicated that if soil temperatures are raised enough to elevate the vapor pressure of a compound above 70 Pa, SVE will remove most of the compound from the soil. Thermally enhanced column study hydrocarbon removal rate constants were shown to have a definable relationship with vapor pressure. The relative removal rate constants also demonstrated an Arrhenius relationship with temperature. Laboratory studies can be used to develop these relationships and the results can be extrapolated within certain temperature ranges and compound types for a given soil.     

The research productivity of academic psychologists: assessment,trends, and best practice recommendations

Research productivity affects the careers of academic psychologists. Unfortunately, there is a surprising lack of consensus on productivity’s meaning, measurement, and how to compare the productivity of one academic psychologist to another. In the present study, we review academic productivity research within psychology, and using a sample of 673 psychologists, compute six indexes of productivity. Most productivity metrics (publication count, citation count, or some combination of the two) were substantially interrelated and one (Integrated Research Productivity Index) was independent from years in the field. Female psychologists were equally as productive as male psychologists after accounting for years in the field, and pre-tenure psychologists showed steeper change-over-time productivity slopes than post-tenure psychologists. Based on these findings, we provide recommendations for the use and measurement of academic research productivity.     

The electrode system in impedance-based ventilation measurement

In this paper, we determined which electrode types, sizes, and locations were best suited for impedance-based ventilation measurement. Optimal electrodes provide high signal-to-(motion) artifact ratio (SAR) and reliability by meeting the following criteria: 1) low baseline impedance, 2) high adhesion, 3) good physical stability, 4) large effective area, 5) thin with high flexibility. We compared 14 electrodes from two main groups: adhesive-gel and conductive rubber electrodes. Adhesive-gel electrodes are easy to apply, make good body contact, and do not slip during the course of an experiment. We found that higher SAR's are obtained when electrode area is increased by connecting several small electrodes together rather than by using a single electrode with a larger area. The peak SAR is achieved when two electrode arrays (area = 70 cm2) are centered at the 8th intercostal spaces on opposite midaxillary lines. To determine the optimal electrode locations, we placed 32 electrodes on the trunk and recorded impedance between 171 electrode combinations on ten normal adult subjects. Based on these data, we conclude that the SAR's are highest when one electrode is placed on the midpoint between the left and right second intercostal spaces on the sternum and the other electrode is placed in the opposite position on the back.     

beta-Amyloid precursor protein isoforms show correlations with neurones but not with glia of demented subjects

Post-mortem cerebral cortex from 15 demented patients was specially collected to minimise autolysis and two membrane fractions and one soluble fraction were quantitatively examined for the major species of beta-amyloid precursor protein (APP) of high apparent molecular mass (> or = 80 kDa) together with the major mRNA species encoding APP isoforms. The number of pyramidal neurones and astrocytes, putative biochemical indices of interneurones and pyramidal neurones, and choline acetyl transferase activity were also determined. Multiple regression analysis has been used to investigate intercorrelations of APP species with biochemical and morphometric measures, free of any effects of confounding demographic variables. Subjects with Alzheimer's disease showed a loss of cholinergic activity and D-aspartate uptake compared with patients with other causes of dementia. The major finding of the study is that measures of neurones rather than astrocytes most closely correlate with the concentration of APP. Pyramidal cell numbers were positively correlated with mRNA for APP695. APP in the soluble fraction showed a negative correlation with pyramidal cell numbers and cholinergic activity. These results indicate that neurones within the cerebral cortex are the major source of APP, and that secretion of APP is dependent upon cortical pyramidal neuronal activity and cholinergic activity.     

Ambient noise statistics

Signal processing algorithms optimized for Gaussian noise may degrade significantly in a non-Gaussian noise environment. Therefore it is important to characterize the noise accurately before including its structure in the formulation of algorithms. A generic distribution suitable for modeling non-Gaussian ambient noise in the kurtosis range 1.8⩽β₂⩽4.2 is derived     

18-42 GHz experimental verification of microstrip coupler and openend capacitance models

A cavity resonance technique is used to experimentally verify microstrip coupler and open end capacitance models over the frequency range of 18-42 GHz. In addition, these results are confirmed using an alternate version of the technique which directly determines open end discontinuity capacitance. In the second case, knowledge of substrate dielectric constant is not required, and the method also yields the microstrip relative effective dielectric constant     

Severity of perinatal cerebral injury and developmental outcome: A dose-response relationship.

The purpose of this study was to establish a dose–response relationship between extent of perinatal cerebral injury and quality of developmental outcome in childhood. To attain this goal, 54 school and preschool-age children who had incurred perinatal intracranial hemorrhage were recruited. The main index of hemorrhage severity—the degree of acute ventriculomegaly observed on the cranial ultrasonogram during the neonatal period—was significantly associated with outcome in all measured domains. These included verbal and nonverbal intelligence, motor skills, and behavioral problems associated with the externalizing and internalizing syndromal groupings. The putative neurobiological mechanisms underlying the observed dose–response relationship between perinatal lesion severity and developmental outcome are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Useful AI tools-a review of heuristic search methods

The classic search methodologies used in artificial intelligence are illustrated. The methods covered are depth-first, breadth-first, best-first or heuristic search, and the uniform-cost method. The power and rationale of heuristic search is discussed     

The influence of personal variables on work-related low-back disorders and implications for future research

Work-related low-back disorders (LBDs) continue to be one of the single largest sources of compensation costs. The relative contributions of personal, workplace, organizational, and environmental variables to the development and severity of LBDs are not completely understood. The inclusion of personal variables in epidemiologic studies of LBDs has been inconsistent, and different authors have different opinions concerning the importance of such variables. Personal variables either known or suspected to influence outcomes are discussed to elucidate the importance of these variables with respect to understanding LBDs and conducting epidemiological studies in industry. The authors suggest that age, gender, injury history, relative strength, smoking, and psychosocial variables be studied further, and that height, weight, pathologies, genetic factors, maximum oxygen uptake, and absolute strength are unlikely to produce significant effects in industrial populations.