On the association between sexual attraction and adolescent risk behavior involvement: Examining mediation and moderation.

On the basis of a large-scale survey of high-school youth, the authors compared adolescents reporting exclusively heterosexual, mostly heterosexual, bisexual, and predominately same-sex attraction based on high-risk involvement across a range of risk behaviors. Bisexual and same-sex attracted groups were characterized by heightened high-risk involvement relative to the other two groups. Mediation analysis was used to determine whether these group disparities were explained by a set of normative predictive factors spanning multiple life domains. Differences among a combined exclusively/mostly heterosexual attraction group and both the bisexual and same-sex attraction groups were attenuated (66% and 50%, respectively) after incorporating the hypothesized intervening predictive factors, providing evidence of partial mediation. Primary mediators included intrapersonal (attitudes toward risk-taking; academic orientation), interpersonal (peer victimization; parental relationships; unstructured activities), and environmental (substance availability) factors. Mediation results were consistent across participant age and sex. Implications, limitations, and directions for future research are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stability and change in adolescent spirituality/religiosity: A person-centered approach.

Although there has been a substantial increase over the past decade in studies that have examined the psychosocial correlates of spirituality/religiosity in adolescence, very little is known about spirituality/religiosity as a domain of development in its own right. To address this limitation, the authors identified configurations of multiple dimensions of spirituality/religiosity across 2 time points with an empirical classification procedure (cluster analysis) and assessed development in these configurations at the sample and individual level. Participants included 756 predominately Canadian-born adolescents (53% female, 47% male) from southern Ontario, Canada, who completed a survey in Grade 11 (M age = 16.41 years) and Grade 12 (M age = 17.36 years). Measures included religious activity involvement, enjoyment of religious activities, the Spiritual Transcendence Index, wondering about spiritual issues, frequency of prayer, and frequency of meditation. Sample-level development (structural stability and change) was assessed by examining whether the structural configurations of the clusters were consistent over time. Individual-level development was assessed by examining intraindividual stability and change in cluster membership over time. Results revealed that a five cluster-solution was optimal at both grades. Clusters were identified as aspiritual/irreligious, disconnected wonderers, high institutional and personal, primarily personal, and meditators. With the exception of the high institutional and personal cluster, the cluster structures were stable over time. There also was significant intraindividual stability in all clusters over time; however, a significant proportion of individuals classified as high institutional and personal in Grade 11 moved into the primarily personal cluster in Grade 12. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

The effect of plastic bending on the electrical properties of indium antimonide

Uniform arrays of In- and Sb-dislocations have been introduced into indium antimonide single crystals by high temperature four-point bending, and the densities of the two types of dislocation estimated by the selective etchants calibrated previously. Hall coefficient and electrical conductivity measurements on bent samples confirm preliminary results that both dislocation types act as acceptor centres in n-type material, and interpretations of the temperature-dependence of the electrical properties on the Read and Broudy models have enabled estimation of the dislocation acceptor levels. A new method of analysing experimental data in terms of the Broudy model has been developed, and the model itself modified for the case where the dislocations are in highly polygonised arrays. The different analyses result in widely different dislocation energy levels. From a comparison of these present results with recent studies of dislocations in p-type material it is concluded that the unmodified Read model is most appropriate and that the In-dislocation level lies near the centre of the band gap while the Sb-level lies near the valence band.     

Mass spectrometry screening of combinatorial mixtures, correlation of measured and predicted electrospray ionization spectra

Methodology was developed to afford rapid characterization of multicomponent mixtures of small organic molecules prepared by split-and-mix combinatorial synthesis. This methodology involved the use of liquid chromatography mass spectrometry (LC/MS) combined with correlation analysis of measured versus predicted electrospray ionization mass spectra. Low-resolution mass spectra of complex mixtures revealed predictable patterns that confirm library products, assisted in identifying chemical synthesis errors, and assessed overall library integrity. In general, equal signal intensities were observed for most combinatorial mixture components, indicating that differences in electrospray ionization efficiency was not a major limitation to this approach. High-throughput data processing programs and informatics tools were used to speed data analysis and to simplify the presentation of the library characterization results. This approach has been used to characterize combinatorial libraries that were synthesized for a variety of drug-discovery programs. Examples are shown for library formats of 1, 40, 66, 280, and 400 component(s)/well. The applicability of this approach to large combinatorial mixtures should allow direct characterization of massive combinatorial libraries.     

Comparison of evaluation methods using structured usability problem reports

. Recent HCI research has produced analytic evaluation techniques which claim to predict potential usability problems for an interactive system.Validation of these methods has involved matching predicted problems against usability problems found during empirical user testing. This paper shows that the matching of predicted and actual problems requires careful attention, and that current approaches lack rigour or generality. Requirements for more rigorous and general matching procedures are presented. A solution to one key requirement is presented: a new report structure for usability problems.It is designed to improve the quality of matches made between usability problems found during empirical user testing and problems predicted by analytic methods. The use of this report format is placed within its design research context, an ongoing project on domain-specific methods for software visualizations.     

Etch-pit studies of dislocations in indium antimonide

Indium antimonide specimens were plastically bent to introduce an excess of dislocations having either In-atoms at the edge of their extra half-planes or having Sb-atoms there. The lower yield stress for bending at 270°C was dependent on the direction of bend, being greater when specimens were bent to produce excess Sb-dislocations.Bent specimens were annealed and the etch-pit densities in them compared with theoretical prediction. It was found that a modified CP4 etch containing butylamine gives a reliable estimate of the total dislocation density (i.e. shows up both In- and Sb-dislocations), whilst the modified CP4 etch without butylamine reveals all the In-dislocations and about half the Sb ones.     

The role of dietary protein intake and resistance training on Myosin heavy chain expression

During resistance training the muscle undergoes many changes. Possibly the most profound and significant changes are those that occur in the muscles contractile proteins. Increases in these contractile proteins are one of the primary factors contributing to myofibrillar hypertrophy. The most abundant muscle protein is myosin, which comprises 25% of the total muscle protein. Due to the large amount of skeletal muscle that is composed of myosin, changes in this fiber may have profound effects on skeletal muscle size and strength. The myosin molecule is made up of 6 subunits, 2 very large heavy chains, and 4 smaller light chains. The myosin heavy chain (MHC) accounts for 25-30% of all muscle proteins making its size an important factor in skeletal muscle growth. In conjunction with resistance training, dietary protein intake must be adequate to illicit positive adaptations. Although many studies have evaluated the role of dietary protein intake on skeletal muscle changes, few have evaluated the MHC specifically. Research has clearly defined the need for dietary protein and resistance training to facilitate positive changes in skeletal muscle. The purpose of this review was to evaluate the current literature on the effects of dietary protein and resistance training on the expression of the myosin heavy chain.     

Disconnection of the anterior cingulate cortex and nucleus accumbens core impairs Pavlovian approach behavior: Further evidence for limbic cortical–ventral striatopallidal systems.

The nucleus accumbens (NAcc) has been implicated in a variety of forms of reward-related learning, reflecting its anatomical connections with limbic cortical structures. After confirming that excitotoxic lesions of the anterior cingulate cortex (Ant Cing) impaired the acquisition of appetitive Pavlovian conditioning in an autoshaping procedure, the effects of excitotoxic lesions to the NAcc core or shell on autoshaping were also assessed. Only selective core lesions impaired Pavlovian approach. A subsequent experiment studied the effects of a disconnection of the Ant Cing and NAcc core, using an asymmetric lesion procedure, to determine whether these structures interact sequentially as part of a limbic corticostriatal system. Such lesioned rats were also significantly impaired relative to controls at autoshaping. These results demonstrate that the NAcc core and Ant Cing are "nodes" of a corticostriatal circuit involved in stimulus-reward learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Electrical studies for an industrial gas turbine cogenerationfacility

Electrical studies are required to assure the proper integration of a gas-turbine cogeneration facility into an existing industrial-plant electrical system and the connected utility grid. Details of such a study are presented, including boundary-limit definition for the system model, individual component modeling, load-flow and short-circuit studies, stability studies, and simulation of online isolation from the electric utility during system undervoltage or underfrequency conditions. The impact of such studies on the design process and plant system reliability is discussed     

Indentation fracture in the In1−x Ga x As y P1−y /InP system and its effect on microhardness anisotropy characteristics

Knoop microhardness anisotropy measurements on the {100}-orientated In_1–x Ga _x As _y P_1–y /InP system have disclosed an appreciable variation in hardness behaviour across the composition range of the alloy. This paper relates these variations to changes in the directional fracture characteristics of the system. The qualitative investigation of both Vickers and Knoop indentation fracture has established the emergence of a secondary 100 cleavage direction at high values of the composition parameter, abovey 0.6. Furthermore, the number and extent of cracks emanating from indentations were seen to increase appreciably asy increases from 0 to 1. A quantitative analysis of Vickers indentation fracture in the quaternary system has indicated a marked dependence of fracture-related parameters on both the indentor orientation and composition. Fracture toughness values from 3.10⁵ to 1.10⁶ N m^/12 have been derived using expressions from the literature. The marked change in Knoop microhardness anisotropy characteristics with increasingy in the In_1–x Ga _x As _y P_1–y /InP system has been partially correlated to the emergence of 100 cleavage and the general increase in indentation fracture, highlighted by the quantitative fracture measurements. Thus, it is concluded that even at very low indentation loads, the effect of fracture on the measured hardness of crystalline materials cannot be ignored.