The application of structural equation modeling to maternal ratings of twins' behavioral and emotional problems.

The application of structural equation modeling to twin data is used to assess the impact of genetic and environmental factors on children's behavioral and emotional functioning. The models are applied to the maternal ratings of behavior of a subsample of 515 monozygotic and 749 dizygotic juvenile twin pairs, ages 8 through 16 yrs, obtained through mailed questionnaires as part of the Medical College of Virginia Adolescent Behavioral Development Twin Project. The importance of genetic, shared, and specific environmental factors for explaining variation is reported for both externalizing and internalizing behaviors, as well as significant differences in the causes of variation in externalizing behaviors among young boys and girls. The usefulness of applying structural equation models to data on monozygotic and dizygotic twins and the potential implications for addressing clinically relevant questions regarding the causes of psychopathology are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Changes in internal tempo and effects on the learning and remembering of event durations.

How changes in internal tempo may influence the learning and remembering of event durations were investigated in 4 experiments with 264 university students. In the 1st 2 experiments, stress or relaxation was induced in Ss after they had learned a set of environmental sounds. When unexpectedly asked to recognize (Exp 1) or reproduce (Exp 2) the sounds' durations, results indicated that relative to a control group, Ss in the stress condition misremembered the time spans as shorter than their actual duration, whereas the opposite pattern of results tended to occur in the relaxation group. Exps 3 and 4 further revealed that changes in internal tempo also influence those event rates to which one is most attuned. Findings are discussed in terms of an approach that emphasizes the reciprocal relationship between individuals and their temporal environment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Does parental involvement influence the academic achievement of Mexican-American eighth graders? Results from the National Education Longitudinal Study.

Examined the influence of parental involvement on the academic achievement of 1,714 8th-grade Mexican-American children. The structural equations model used considers and controls for diversity of family backgrounds and values, parents' English language proficiency and place of birth, students' previous achievement, and home rules. The most salient finding was that parental involvement influenced overall academic achievement, as well as promoting gains in the specific subject areas of reading, mathematics, science, and social studies. The strongest influence on academic achievement was previous achievement. Parents' English proficiency influenced parental involvement; those parents with less proficiency had higher educational aspirations for their children. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Preharvest internalization of Escherichia coli O157:H7 into lettuce leaves, as affected by insect and physical damage

Environmental pests may serve as reservoirs and vectors of zoonotic pathogens to leafy greens; however, it is unknown whether insect pests feeding on plant tissues could redistribute these pathogens present on the surface of leaves to internal sites. This study sought to differentiate the degree of tissue internalization of Escherichia coli O157:H7 when applied at different populations on the surface of lettuce and spinach leaves, and to ascertain whether lettuce-infesting insects or physical injury could influence the fate of either surface or internalized populations of this enteric pathogen. No internalization of E. coli O157:H7 occurred when lettuce leaves were inoculated with 4.4 log CFU per leaf, but it did occur when inoculated with 6.4 log CFU per leaf. Internalization was statistically greater when spinach leaves were inoculated on the abaxial (underside) than when inoculated on the adaxial (topside) side, and when the enteric pathogen was spread after surface inoculation. Brief exposure (～18 h) of lettuce leaves to insects (5 cabbage loopers, 10 thrips, or 10 aphids) prior to inoculation with E. coli O157:H7 resulted in significantly reduced internalized populations of the pathogen within these leaves after approximately 2 weeks, as compared with leaves not exposed to insects. Surface-contaminated leaves physically injured through file abrasions also had significantly reduced populations of both total and internalized E. coli O157:H7 as compared with nonabraded leaves 2 weeks after pathogen exposure.     

Perceptually lossless medical image coding

A novel perceptually lossless coder is presented for the compression of medical images. Built on the JPEG 2000 coding framework, the heart of the proposed coder is a visual pruning function, embedded with an advanced human vision model to identify and to remove visually insignificant/irrelevant information. The proposed coder offers the advantages of simplicity and modularity with bit-stream compliance. Current results have shown superior compression ratio gains over that of its information lossless counterparts without any visible distortion. In addition, a case study consisting of 31 medical experts has shown that no perceivable difference of statistical significance exists between the original images and the images compressed by the proposed coder.     

Nanoscale glassification of gold substrates for surface plasmon resonance analysis of protein toxins with supported lipid membranes

Surface plasmon resonance (SPR) spectroscopy, a powerful tool for biosensing and protein interaction analysis, is currently confined to gold substrates and the relevant surface chemistries involving dextran and functional thiols. Drawbacks of using self-assembled monolayers (SAMs) for SPR-related surface modification include limited stability, pinhole defects, bioincompatibility, and nonspecific protein adsorption. Here we report the development of stable nanometer-scale glass (silicate) layers on gold substrates for SPR analysis of protein toxins. The nanoscale silicate layers were built up with layer-by-layer deposition of poly(allylamine hydrochloride) and sodium silicate, followed by calcination at high temperature. The resulting silicate films have a thickness ranging from 2 to 15 nm and demonstrate outstanding stability in flow cell conditions. The use of these surfaces as a platform to construct supported bilayer membranes (SBMs) is demonstrated, and improved performance against protein adsorption on SBM-coated surfaces is quantified by SPR measurements. SBMs can be formed reproducibly on the silicate surface via vesicle fusion and quantitatively removed using injection of 5% Triton X-100 solution, generating a fresh surface for each test. Membrane properties such as lateral diffusion of the SBMs on the silicate films are characterized with photobleaching methods. Studies of protein binding with biotin/avidin and ganglioside/cholera toxin systems show detection limits lower than 1 microg/mL (i.e., nanomolar range), and the response reproducibility is better than 7% RSD. The method reported here allows many assay techniques developed for glass surfaces to be transferred to label-free SPR analysis without the need for adaptation of protocols and time-consuming synthetic development of thiol-based materials and opens new avenues for developing novel bioanalytical technologies for protein analysis.     

Environmental Considerations for a Proposed Tolled Highway Project

As federal dollars available for highway projects are tightened and as demand for more highway capacity continues to increase, transportation officials seek more innovative financing methods. One of the more common methods has been to toll new highway projects. Recently, tollways also have been considered for existing, free-access roadways, i.e., nontolled, infrastructure segments. Transportation planners must consider that this so-called “innovative” financing technique, i.e., the decision to toll existing and new roadways, is subject to provisions of the National Environmental Protection Act (NEPA). This renewed interest in tolling mandates that transportation planners revisit the requirements of NEPA, and in this context, its applicability to decisions to toll roads for financing of highway projects. NEPA requires that, prior to construction of a bridge or highway, the head of the federal agency that is committing funds to the project must evaluate the effect of the project on the human environment; the effect of the project on the habitat of an endangered species, which implicates provisions of the Endangered Species Act; the effect of the project on any historic properties in the vicinity of the project, which implicates provisions of the National Historic Preservation Act, and the effect of the project on minority or low-income-populations, called environmental justice, which implicates Title VI of the Civil Rights Act of 1964. In this paper, we analyze the requirements of NEPA as they relate to Title VI of the Civil Rights Act of 1964. The interrelation of the two acts now mandates that the transportation planner consider an environmental justice concept in planning for highway and bridge projects. The intent of this paper is to provide some guidance to transportation planners in light of the environmental justice issues implicated by Title VI of the Civil Rights Act of 1964 as they begin the planning stages for highway and bridge projects.     

Toughening of a high‐temperature polymer by the sol–gel,in situ generation of a rubbery silica–siloxane phase

A phenyl ether phenyl phosphate polymer, specifically poly(biphenyl ether triphenyl phosphate), was modified to increase its tractability and to improve its toughness. The first goal was achieved by increasing its solubility by sulfonation of the chain, and the second, by the in situ generation of a rubbery phase. This phase was generated by a modification of the usual sol–gel reaction (which usually generates a hard silicalike material by the hydrolysis of a tetrafunctional organosilicate). In this case, a difunctional silicate was included, thus introducing some softening organic groups into the dispersed phase. A bonding agent, N,N‐diethylaminopropyltrimethoxysilane, was also included to improve the bonding between the two phases in this organic–inorganic composite. As expected, the glass transition temperatures generally increased slightly upon sulfonation, but decreased significantly upon introduction of the rubbery phase. Most important, the toughness of the polymer was successfully increased with, for example, only 8 wt % of the rubbery phase, quadrupling extensibility to 20 % and markedly increasing the toughness. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 79: 2326–2330, 2001