The acculturation gap-distress hypothesis among high-risk Mexican American families.

The authors tested the acculturation gap-distress hypothesis by examining whether parent-adolescent acculturation gaps were associated with greater conflict and youth conduct problems among 260 high-risk Mexican American families. The authors operationalized acculturation gaps in 2 ways: parent-youth mismatches in acculturation style, and parent-youth discrepancies in acculturation toward both mainstream and heritage cultures. Acculturation gaps were common, but results of hierarchical regression analyses indicated that parent-youth discrepancies in acculturation toward mainstream and heritage cultures were not related to increased conflict or youth conduct problems. Conduct problems were no higher in families in which the adolescent was more aligned with mainstream culture than the parent. Unexpectedly, the authors found more youth conduct problems in families in which the youth was more aligned with traditional culture than the parent. The results call into question the assumption that the more rapid acculturation of adolescents to American culture inevitably leads to distress in minority families. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Musculocutaneous neurectomy for spastic elbow flexion in non-functional upper extremities in adults

The charts of twenty-nine patients who had undergone thirty musculocutaneous neurectomies for acquired spasticity of the elbow in a non-functional upper extremity were reviewed. The most common causes of the spasticity were cerebrovascular accident (59 per cent) and head injury (24 per cent). The aims of the operation were to increase the patient's capacity for self-care and to improve ambulation, personal hygiene, and appearance. Patients who had 30-degree flexion contractures preoperatively did not require a cast postoperatively; those who had 30 to 75-degree flexion contractures preoperatively required a cast postoperatively; and patients who had flexion contractures of more than 75 degrees preoperatively required a concomitant release of soft tissue in the elbow and application of a cast postoperatively. One patient who was operated on to improve appearance had no active elbow flexion postoperatively and was regarded as having a poor result. Musculocutaneous neurectomy is a safe, reliable procedure for treating the spastic elbow in the non-functional upper extremity.     

Control of concentration during academic tasks.

Evaluated 3 strategies for controlling concentration during academic tasks. 82 undergraduates served as Ss. One strategy, self-initiated relaxation (SIR), required Ss to employ a combination of relaxation techniques to set and maintain constructive study and test-taking states. The 2nd strategy, self-coaching (SC), was an extension of the positive self-talk techniques developed by D. Meichenbaum (1972). Ss were taught to coach (talk) themselves into constructive states and to maintain these states during studying and test taking. Finally, a 3rd strategy that combined SIR and SC was created. Results indicate that the 3rd strategy, SIR plus SC, significantly facilitated some aspects of academic performance in comparison to a no-treatment control group. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The development of compression damage zones in fibrous composites

Recent experimental work (Narayanan S, Schadler LS. Mechanisms of kink band formation in graphite/epoxy compsites: a micromechanical experimental study. Comp Sci Technol 1999; 59:2201-13) suggests that kink bands in unidirectional continuous carbon fiber reinforced polymer composites initiate from damage zones formed under axial compressive loads. A damage zone consists of a cluster of locally crushed fibers and broken fibers, that are often fractured at an angle, θ > 0°, normal to the fiber axis. Typically, under compressive loads, fiber breaks in damage zones form roughly along a plane at an angle φ, normal to the fiber axis. These damage zones produce stress concentrations which can lead to instabilities in the nearby fiber and matrix and initiate microbuckling and kink bands. This paper extends a micromechanical influence function technique based on earlier shear lag fiber composite models. Our modified technique calculates the fiber axial and matrix shear stress concentrations due to multiple angled and crushed fibers in arbitrary configurations. Modeling reveals that angled or ‘shear’ breaks (θ > 0°) can lead to higher shear stress concentrations in the matrix than transverse breaks (θ=0°). Also we find that the damage zone is more likely to form at an angle φ, which is greater than that of its individual fiber breaks, θ. When φ is slightly greater than θ, the shear stress in the surrounding matrix regions within the damage zone achieves a maximum, potentially weakening the matrix and interface and consequently leading to kink band formation. Monte Carlo simulations incorporating this stress analysis predict that the initiation and propagation of crushed and angled breaks progress roughly along an angle, φ ≈ 17° in a linear elastic system. When possible, our model results are compared to strain measurements of fiber composites under compression obtained by Narayanan and Schadler using micro-Raman spectroscopy (MRS).     

Vortex coupling in Bi2Sr2CaCu2O8+y,using controlled sample geometry

The flux transformer geometry has been useful for studying vortex coupling in Bi₂Sr₂CaCu₂O_8+y crystals but is limited by the difficulty of controlling sample size. We have used an argon ion mill to etch two channels into the top face of a Bi₂Sr₂CaCu₂O_8+y crystal to reproduce the effects of the flux transformer geometry with more precise control over effective sample dimensions. The temperature dependence of the transformer voltage in such a crystal shows a pronounced peak between 87 K and 89 K which is linear with current. Application of a magnetic field (H c-axis) sharply suppresses the peak, broadens it, and shifts it to lower temperatures. The peak in the transformer voltage and its current and field dependence are consistent with interlayer Josephson coupling of thermally excited vortices.     

Alert eyes and DWIs: An indirect evaluation of a DWI witness reward program in Stockton, CA

We evaluate a “grassroots” anonymous reward program targeting drunken driving in Stockton, CA. The time-series cross-sectional data covers 19 years for Stockton and six other California cities. Exploiting interrupted time-series regression, Zellner's seemingly unrelated regression (SUR) framework, and bootstrapped standard errors, we test for an impact of this program on alcohol-related injury or fatality accidents, the proportion of all accidents involving alcohol, and the number of DWI arrests. In its first decade, the citizen reward program appears to have averted some 275 alcohol-related accidents for social cost savings of between $21,000 and $5.6 million. Further, possibly 4495 arrests were precluded, saving some $1-3 million in arrest-related costs. Incentivized public monitoring of driving-after-drinking may be an effective drunken driving abatement program though our exploratory findings need further confirmation.     

HPLC/ESI-quadrupole ion trap mass spectrometry for characterization and direct quantification of amphoteric and nonionic surfactants in aqueous samples

An amphoteric (cocamidopropylbetaine, CAPB) and a nonionic (alcohol polyethoxylate, AE) surfactant were characterized by electrospray ionization quadrupole ion trap mass spectrometry (ESI-MS) as to their homologue distribution and ionization/fragmentation chemistry. Quantitative methods involving reversed-phase gradient HPLC and (+)ESI-MSn were developed to directly determine these surfactants in hydroponic plant growth medium that received simulated graywater. The predominant homologues, 12 C alkyl CAPB and 9 EO AE, were monitored to represent the total amount of the respective surfactants. The methods demonstrated dynamic linear ranges of 0.5-250 ng (r2 > 0.996) for CAPB and 8-560 ng (r2 > 0.998) for AE homologue mixture, corresponding to minimum quantification limits of 25 ppb CAPB and 0.4 ppm AE with 20-microL injections. This translated into an even lower limit for individual components due to the polydispersive nature of the surfactants. The procedure was successfully employed for the assessment of CAPB and AE biodegradation in a hydroponic plant growth system used as a graywater bioreactor.