Drug use, violence, and victimization among White American, Mexican American, and American Indian dropouts, students with academic problems, and students in good academic standing.

Problem-prone behaviors of White American, Mexican American, and American Indian high school dropouts, students in good academic standing, and students in poor academic standing were surveyed. Generally, dropouts were most involved with drugs, perpetration of violence, and victimization by violence, students in poor standing were the next most involved, and students in good standing were least involved. Ethnicity did not interact with academic status, suggesting that differences between dropouts and students were similar across ethnic groups. Some ethnicity and gender main effects were found. Findings were related to R. Jessor's (see record 1992-23064-001) theory of problem-prone behaviors, to peer cluster theory, and to intervention design. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Apparent diffusion coefficient determination of sodium hydroxide through potato skin and flesh under different temperatures and concentration conditions

The aims of the present study were to analyze the most important chemical reactions between sodium hydroxide and potato constituents involved in potato chemical peeling, and to measure the apparent diffusivity of NaOH in potato skin and flesh separately, as a function of temperature and NaOH concentration, selected according to potato chemical peeling process. Chemical reaction of the suberin of the potato skin with NaOH was proposed as the most important one to promote chemical peeling. Whereas starch hydrolysis, middle lamella dissolution and cell wall disruptions were proposed as the principal chemical reactions in flesh. Experiments to determine NaOH apparent dijfusivities in skin and flesh were performed following a cell diffusion method at 25, 40, 50, 60 and 70 °C temperatures and concentrations of 4, 12 and 20 g NaOH/100 g of solution. Finally, correlation equations were determined to describe apparent diffusivity dependence on temperature and concentration.     

A scalable solution to the nearest neighbor search problem through local-search methods on neighbor graphs

Pattern Analysis and Applications - Nearest neighbor search is a powerful abstraction for data access; however, data indexing is troublesome even for approximate indexes. For intrinsically...     

Ultra-low noise front-end electronics for air-coupled ultrasonic non-destructive evaluation

Air-coupled ultrasonic inspection has been demonstrated to be a non-contact method of great interest in non-destructive evaluation (NDE) applications. The absence of direct contact or a liquid couplant provides this technique very attractive benefits in front of the well-known and well-developed liquid-coupled ultrasonic inspection systems. A wide range of defects can be detected by means of ultrasound coupled to and harvested from the specimen in absence of contact when using appropriate transducers designed for their operation in air.This paper presents an easy way to integrate air-coupled piezoelectric transducers in conventional ultrasonic NDE equipment. The design of a specific front-end electronics by using an ultra-low noise amplifier enables existing inspection systems to be used for the dry-coupled ultrasonic test of materials and structures. The amplifier provides the receiver with a signal-to-noise ratio large enough for good quality signal processing and imaging. System dynamic ranges of more than 100 dB are achieved.     

A Transactional Model of Parent-Infant Interactions in Alcoholic Families.

This study examined the transactional nature of parent-infant interactions over time among alcoholic and nonalcoholic families. The sample consisted of 222 families assessed at 12, 18, and 24 months of child age. Results indicated that infant behavior did not influence parental behavior across time, but parental behavior was longitudinally predictive of infant behavior during play interactions. Higher paternal alcohol consumption at 12 months was longitudinally predictive of negative parental behavior at 24 months. Other significant risk factors included marital conflict, fathers' depression, and fathers' education. Results highlight the nested nature of risk in alcoholic families and the direction of influence from parent to child during interactions and suggest that 1 pathway to risk among these children is through negative parent-infant interactions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Conditional and Marginal Mutual Information in Gaussian and Hyperbolic Decay Time Series

We consider the amount of available information about an arbitrary future state of a Gaussian stochastic process. We derive an infinite series for the marginal mutual information in terms of the autocorrelation function. We derive an infinite series for the newly available information for prediction, the conditional mutual information, in terms of the moving average parameters, and directly characterize predictability in terms of sensitivity to random shocks. We apply our results to long memory, or more generally, hyperbolic decay models, and give information‐theoretic characterizations of the transition from persistence to anti‐persistence, stationary long memory to nonstationarity, and a stationary regime where the mutual information is not summable.     

Combustion Properties of Amino‐Substituted Guanidinium 4,4′,5,5′‐Tetranitro‐2,2′‐biimidazolate(N4BIM) Salts

This paper describes the combustion properties of the amino‐substituted guanidinium 4,4′,5,5′‐tetranitro‐2,2′‐biimidazolate (N4BIM) series, including the bis‐mono, di and triaminoguanidinium salts. These salts are of interest as propellant ingredient additives, and in particular, the bis‐triaminoguanidinium salt of N4BIM displays excellent burn rate and combustion behavior. Our combustion studies have shown that TAGN4‐BIM displays a fast burning rate and has the lowest pressure dependence exponent yet measured for a triaminoguanidinium salt.     

Imide‐containing ladder polyphenylsilsesquioxanes with high thermal stability and thermoplastic properties

This work reports for the first time the synthesis of ladder polyphenylsilsesquioxanes containing imide building blocks as parts of the main parallel chains. The ladder structure of the synthesized polymers was documented by means of small angle X‐ray scattering (SAXS) measurements. The obtained ladder polymers exhibit stability with respect to decomposition up to temperatures as high as 460°C; additionally, they have melting points far below their decomposition temperatures, which make them interesting candidate materials for thermoplastic processing. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40085.     

A theoretical approach to some analytical properties of heterogeneous enzymatic assays

Heterogeneous enzymatic assays (HEA), where an enzyme in solution acts upon an immobilized substrate, are been increasingly used. Given their high throughput and versatility they hold great potential for developing massive enzyme inhibitor screening. However, current HEA lack, in general, rigorous quantitative use. This is in part due to technical problems as a multiplicity of suboptimal substrate populations achieved with traditional immobilization techniques but, more importantly, is due to a poor understanding of the particular kinetic behavior of these systems. This paper addresses the kinetic features of HEA that arise from the very low amount of solid-phase substrate and the resulting inalterability of the free enzyme concentration during the assay, which classify HEA as enzyme quasi-saturable systems (EQSS). We assessed the optimal enzyme concentration working range and time of reaction. We also considered certain attributes of HEA for evaluating isosteric inhibitors. These studies were done on the basis of a simplified model for the kinetics of EQSS and a formal splitting of the functional factor of the analytical sensitivity of an enzymatic assay into [E(o)]/K(m)-dependent and temporal components.