One-dimensional numerical analysis of the transient thermal response of multilayer insulative systems

A one-dimensional numerical analysis of the transient thermal response of multilayer insulative systems has been developed. The analysis can determine the temperature distribution through a system consisting of from one to four layers, one of which can be an air gap. Concentrated heat sinks at any interface can be included. The computer program based on the analysis will determine the thickness of a specified layer that will satisfy a temperature limit criterion at any point in the insulative system. The program will also automatically calculate the thickness at several points on a vehicle and determine total system mass

Life Satisfaction: Measurement Invariance and Correlations with Adolescent Adjustment

Background Low life satisfaction during adolescence has been associated with adjustment problems. There are few well-validated measures available to assess adolescents’ life-satisfaction. The purpose of this study was to investigate the structure of the Life Satisfaction Scale, evaluate its measurement invariance across sex and race/ethnicity, and investigate its associations with related constructs. Methods Participants were 3,340 adolescents from rural middle schools in Florida. Half the participants were female, 51% were White, 15% were Black, and 22% were Latinx. Adolescents completed the Life Satisfaction Scale, the Children’s Report of Exposure to Violence scale, and the Problem Behavior Frequency Scale. Results Confirmatory factor analysis found support for a single factor representing overall life satisfaction, and strong measurement invariance across race, but not across sex. There were significant differences in item thresholds such that girls at the same level of life satisfaction as boys, were more likely to endorse higher responses to items assessing satisfaction with school, with themselves, and with their friendships. Life satisfaction had significant negative correlations with violence exposure, problem behavior, and peer pressure for drug use. Conclusion Findings suggest that the Life Satisfaction Scale may be suitable for assessing life satisfaction across different groups of adolescents. Examining sex differences must be done cautiously as life satisfaction may have different meanings to boys and girls. The inverse correlations between life satisfaction, violence exposure and problem behavior across groups highlights the importance of developing sound measures to assess this important construct and determine how it relates to youth adjustment.https://scholarscompass.vcu.edu/gradposters/1076/thumbnail.jp

Competing Models of Exposure to Community Violence Among Urban Youth: Dimensional Versus Person-Centered Approaches

Exposure to community violence is prevalent among urban youth residing in neighborhoods with high rates of crime and violence. Although there is strong evidence suggesting that community violence exposure is associated with negative consequences on youth development, there are inconsistencies in theories and evidence regarding the nature of these associations. Methodological limitations of dimensional approaches to conceptualizing exposure, including the assumption that adolescents are similar in their frequency and patterns of exposure, likely contribute to the inconsistencies in findings of associations. Recently, person-centered methods have been used to elucidate associations between community violence exposure and consequences on adolescent development. However, studies have not compared variable-centered and person-centered approaches and their associations with adolescent aggression and anxiety. The main goal of this study was to test competing models of dimensions of community violence exposure and compare them to person-centered models of exposure. Dimensional analyses indicated that a hybrid model of hypothesized models, with factors representing witnessing less severe violence, witnessing severe violence, and victimization, best represented adolescents’ exposure to community violence. Identified factors or constructs of exposure differed in their associations with physical aggression and anxiety. In contrast, person-centered analyses revealed five subgroups of adolescents with distinct patterns of community violence exposure that differed in their levels of physical aggression and symptoms of anxiety. Overall, results suggest that victimization by community violence was associated with physical aggression and symptoms of anxiety. Witnessing community violence was only uniquely associated with physical aggression. Victimization by community violence and witnessing community violence might impact adolescent development through different mechanisms. Future research should include investigating longitudinal associations between constructs of exposure, and different patterns of exposure to understand impact on development. Further research examining different mechanisms that might underly the associations between witnessing and aggression and anxiety, and victimization and aggression and anxiety, is necessary to refine our understanding of exposure and its impact on youth development

Experimental Controlled-NOT Logic Gate for Single Photons in the Coincidence Basis

We report a proof-of-principle demonstration of a probabilistic controlled-NOT gate for single photons. Single-photon control and target qubits were mixed with a single ancilla photon in a device constructed using only linear optical elements. The successful operation of the controlled-NOT gate relied on post-selected three-photon interference effects which required the detection of the photons in the output modes.Comment: 4 pages, 4 figures; minor change

Photon number resolution using a time-multiplexed single-photon detector

Photon number resolving detectors are needed for a variety of applications including linear-optics quantum computing. Here we describe the use of time-multiplexing techniques that allows ordinary single photon detectors, such as silicon avalanche photodiodes, to be used as photon number-resolving detectors. The ability of such a detector to correctly measure the number of photons for an incident number state is analyzed. The predicted results for an incident coherent state are found to be in good agreement with the results of a proof-of-principle experimental demonstration.Comment: REVTeX4, 6 pages, 8 eps figures, v2: minor changes, v3: changes in response to referee report, appendix added, 1 reference adde

Phylogenetic analysis and protein structure modelling identifies distinct Ca2+/Cation antiporters and conservation of gene family structure within Arabidopsis and rice species

BACKGROUND: The Ca(2+)/Cation Antiporter (CaCA) superfamily is an ancient and widespread family of ion-coupled cation transporters found in nearly all kingdoms of life. In animals, K(+)-dependent and K(+)-indendent Na(+)/Ca(2+) exchangers (NCKX and NCX) are important CaCA members. Recently it was proposed that all rice and Arabidopsis CaCA proteins should be classified as NCX proteins. Here we performed phylogenetic analysis of CaCA genes and protein structure homology modelling to further characterise members of this transporter superfamily. FINDINGS: Phylogenetic analysis of rice and Arabidopsis CaCAs in comparison with selected CaCA members from non-plant species demonstrated that these genes form clearly distinct families, with the H(+)/Cation exchanger (CAX) and cation/Ca(2+) exchanger (CCX) families dominant in higher plants but the NCKX and NCX families absent. NCX-related Mg(2+)/H(+) exchanger (MHX) and CAX-related Na(+)/Ca(2+) exchanger-like (NCL) proteins are instead present. Analysis of genomes of ten closely-related rice species and four Arabidopsis-related species found that CaCA gene family structures are highly conserved within related plants, apart from minor variation. Protein structures were modelled for OsCAX1a and OsMHX1. Despite exhibiting broad structural conservation, there are clear structural differences observed between the different CaCA types. CONCLUSIONS: Members of the CaCA superfamily form clearly distinct families with different phylogenetic, structural and functional characteristics, and therefore should not be simply classified as NCX proteins, which should remain as a separate gene family. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12284-016-0075-8) contains supplementary material, which is available to authorized users

Desmin forms toxic, seeding-competent amyloid aggregates that persist in muscle fibers

Desmin-associated myofibrillar myopathy (MFM) has pathologic similarities to neurodegeneration-associated protein aggregate diseases. Desmin is an abundant muscle-specific intermediate filament, and disease mutations lead to its aggregation in cells, animals, and patients. We reasoned that similar to neurodegeneration-associated proteins, desmin itself may form amyloid. Desmin peptides corresponding to putative amyloidogenic regions formed seeding-competent amyloid fibrils. Amyloid formation was increased when disease-associated mutations were made within the peptide, and this conversion was inhibited by the anti-amyloid compound epigallocatechin-gallate. Moreover, a purified desmin fragment (aa 117 to 348) containing both amyloidogenic regions formed amyloid fibrils under physiologic conditions. Desmin fragment-derived amyloid coaggregated with full-length desmin and was able to template its conversion into fibrils in vitro. Desmin amyloids were cytotoxic to myotubes and disrupted their myofibril organization compared with desmin monomer or other nondesmin amyloids. Finally, desmin fragment amyloid persisted when introduced into mouse skeletal muscle. These data suggest that desmin forms seeding-competent amyloid that is toxic to myofibers. Moreover, small molecules known to interfere with amyloid formation and propagation may have therapeutic potential in MFM

Examining Natural Selection by Sketching and Making Models of the Finches of the Galapagos Islands

This practical lesson describes how students in six eighth grade science classes participated in a lesson combining the National Core Arts Standards with the Next Generation Science Standards. The goal of the lesson was to provide visual representations of finch beak form and function so students could better understand genetic variation and how environmental pressures influence natural selection. Students sketched a finch with a large, medium, or small beak, corresponding to an experiment they had conducted with picking up different sizes of seeds with different sizes of binder clips. Using modeling with a variety of media, students created bird beaks based on information from online and text research. Students identified how each beak was related to the bird’s diet and made comparisons with the beaks of the other birds in the environment. In addition to their increased knowledge of natural selection, students voiced their enjoyment of the inclusion of art