754 research outputs found

    Effects of dynamic loads on plate girder panels

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    This paper presents a brief theoretical and experimental study of the effects of dynamic loads on plate girder panels. Dynamic response of plate girders, expressed in terms of a dynamic load factor, was evaluated for sinusoidally varying loads

    Closing the Water Budget in an Experimental Urban Watershed: A Comparative Assessment of Methods for Measuring Evapotranspiration

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    From Conflict to Collaboration: Exploring Influences on Community Well-Being

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    Decades after the Timber Wars, land management agencies continue to redefine approaches to forest restoration and management, with impacts for Western forest dependent communities. To better understand this evolving dynamic, we examined the recent history of a rural forest community in the northern Sierra Nevada against the backdrop of changing perspectives on and relationships to resource use, industry, and forest management. Guided by community priorities distilled from interview data, we examine the transition from the Timber Wars to collaborative forest management through the rise of area collaboratives. The success of this work and its potential to genuinely improve community well-being remains to be seen but a notable shift has begun. With this paper we aim to advance understanding of the transition from the Timber Wars to community-based collaborative efforts, and what this means for rural forest communities

    Transport properties of heterogeneous materials derived from Gaussian random fields: Bounds and Simulation

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    We investigate the effective conductivity (σe\sigma_e) of a class of amorphous media defined by the level-cut of a Gaussian random field. The three point solid-solid correlation function is derived and utilised in the evaluation of the Beran-Milton bounds. Simulations are used to calculate σe\sigma_e for a variety of fields and volume fractions at several different conductivity contrasts. Relatively large differences in σe\sigma_e are observed between the Gaussian media and the identical overlapping sphere model used previously as a `model' amorphous medium. In contrast σe\sigma_e shows little variability between different Gaussian media.Comment: 15 pages, 14 figure

    Posterior lung herniation after a coughing spell: a case report

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    Lung hernias are rare, occurring most commonly after trauma or surgery. Spontaneous lung hernias are even rarer and have only been reported as occurring anteriorly. We present a 72-year-old male who developed a spontaneous posterior lung hernia after a severe coughing episode. We describe the evaluation and surgical management of this unusual condition and provide a brief review of the literature

    Apparent Fractality Emerging from Models of Random Distributions

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    The fractal properties of models of randomly placed nn-dimensional spheres (nn=1,2,3) are studied using standard techniques for calculating fractal dimensions in empirical data (the box counting and Minkowski-sausage techniques). Using analytical and numerical calculations it is shown that in the regime of low volume fraction occupied by the spheres, apparent fractal behavior is observed for a range of scales between physically relevant cut-offs. The width of this range, typically spanning between one and two orders of magnitude, is in very good agreement with the typical range observed in experimental measurements of fractals. The dimensions are not universal and depend on density. These observations are applicable to spatial, temporal and spectral random structures. Polydispersivity in sphere radii and impenetrability of the spheres (resulting in short range correlations) are also introduced and are found to have little effect on the scaling properties. We thus propose that apparent fractal behavior observed experimentally over a limited range may often have its origin in underlying randomness.Comment: 19 pages, 12 figures. More info available at http://www.fh.huji.ac.il/~dani

    Pediatric Health-Related Quality of Life: Feasibility, Reliability and Validity of the PedsQL™ Transplant Module

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    The measurement properties of the newly developed Pediatric Quality of Life Inventory™ (PedsQL™) 3.0 Transplant Module in pediatric solid organ transplant recipients were evaluated. Participants included pediatric recipients of liver, kidney, heart and small bowel transplantation who were cared for at seven medical centers across the United States and their parents. Three hundred and thirty-eight parents of children ages 2–18 and 274 children ages 5–18 completed both the PedsQL™ 4.0 Generic Core Scales and the Transplant Module. Findings suggest that child self-report and parent proxy-report scales on the Transplant Module demonstrated excellent reliability (total scale score for child self-report α= 0.93; total scale score for parent proxy-report α= 0.94). Transplant-specific symptoms or problems were significantly correlated with lower generic HRQOL, supporting construct validity. Children with solid organ transplants and their parents reported statistically significant lower generic HRQOL than healthy children. Parent and child reports showed moderate to good agreement across the scales. In conclusion, the PedsQL™ Transplant Module demonstrated excellent initial feasibility, reliability and construct validity in pediatric patients with solid organ transplants.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79306/1/j.1600-6143.2010.03149.x.pd

    Positive youth development in swimming: clarification and consensus of key psychosocial assets

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    The purpose of this study was to gain a more cohesive understanding of the assets considered necessary to develop in young swimmers to ensure both individual and sport specific development. This two stage study involved (a) a content analysis of key papers to develop a list of both psychosocial skills for performance enhancement and assets associated with positive youth development, and (b) in-depth interviews involving ten expert swim coaches, practitioners and youth sport scholars. Five higher order categories containing seventeen individual assets emerged. These results are discussed in relation to both existing models of positive youth development and implications for coaches, practitioners and parents when considering the psychosocial development of young British swimmers

    Childhood loneliness as a predictor of adolescent depressive symptoms: an 8-year longitudinal study

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    Childhood loneliness is characterised by children’s perceived dissatisfaction with aspects of their social relationships. This 8-year prospective study investigates whether loneliness in childhood predicts depressive symptoms in adolescence, controlling for early childhood indicators of emotional problems and a sociometric measure of peer social preference. 296 children were tested in the infant years of primary school (T1 5 years of age), in the upper primary school (T2 9 years of age) and in secondary school (T3 13 years of age). At T1, children completed the loneliness assessment and sociometric interview. Their teachers completed externalisation and internalisation rating scales for each child. At T2, children completed a loneliness assessment, a measure of depressive symptoms, and the sociometric interview. At T3, children completed the depressive symptom assessment. An SEM analysis showed that depressive symptoms in early adolescence (age 13) were predicted by reports of depressive symptoms at age 8, which were themselves predicted by internalisation in the infant school (5 years). The interactive effect of loneliness at 5 and 9, indicative of prolonged loneliness in childhood, also predicted depressive symptoms at age 13. Parent and peer-related loneliness at age 5 and 9, peer acceptance variables, and duration of parent loneliness did not predict depression. Our results suggest that enduring peer-related loneliness during childhood constitutes an interpersonal stressor that predisposes children to adolescent depressive symptoms. Possible mediators are discussed
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