11,249 research outputs found

    Hybridisation for versatile decision-making in game opponent AI

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    Hybridisation for versatile decision-making in game opponent A

    An analysis of independent custody visiting in Scotland

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    Muscular and non-muscular contributions to maximum power cycling in children and adults: implications for developmental motor control

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    This article is available open access through the publisher’s website at the link below.During submaximal cycling, children demonstrate a different distribution between muscular and non-muscular (gravitational and motion-dependent) forces when compared with adults. This is partly due to anthropometric differences. In this study, we tested the hypothesis that during maximum power cycling, children would construct the task (in terms of the distribution between muscular and non-muscular pedal power) similarly to adults. Eleven children (aged 8–9 years) and 13 adults (aged 20–40 years) performed a maximal isokinetic cycling task over 3 s at 115 r.p.m. Multivariate analyses of variance revealed no significant differences in normalized maximum, minimum and average positive non-muscular pedal power between children and adults (Wilks' λ=0.755, F3,20=2.17, P=0.124). Thus, maximum cycling is a developmental `self-scaling' task and age-related differences in muscular power production are not confounded by differences in anthropometry. This information is useful to researchers who wish to differentiate between muscular and non-muscular power when studying developmental motor control. In addition to the similarities in the distribution between muscular and non-muscular pedal power, we found age-related differences in the relative joint power contributions to total pedal power. In children, a significantly smaller proportion of total pedal power was generated at the ankle joint (6.1±5.4% for children and 12.6±3.2% for adults), whilst relatively more power was generated at the knee and hip joints. These results suggest that intermuscular coordination may be contributing to children's limits in maximum power production during multi-joint tasks

    Fatigue and Recovery from Dynamic Contractions in Men and Women Differ for Arm and Leg Muscles

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    Introduction: Whether there is a gender difference in fatigue and recovery from maximal velocity fatiguing contractions and across muscles is not understood. Methods: Sixteen men and 19 women performed 90 isotonic contractions at maximal voluntary shortening velocity (maximal velocity concentric contractions, MVCC) with the elbow flexor and knee extensor muscles (separate days) at a load equivalent to 20% maximal voluntary isometric contraction (MVIC). Results: Power (from MVCCs) decreased similarly for men and women for both muscles (P \u3e 0.05). Men and women had similar declines in MVIC of elbow flexors, but men had greater reductions in knee extensor MVIC force and MVIC electromyogram activity than women (P \u3c 0.05). The decline in MVIC and power was greater, and force recovery was slower for the elbow flexors compared with knee extensors. Conclusions: The gender difference in muscle fatigue often observed during isometric tasks was diminished during fast dynamic contractions for upper and lower limb muscles

    Bright Ultraviolet Regions and Star Formation Characteristics in Nearby Dwarf Galaxies

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    We compare star formation in the inner and outer disks of 11 dwarf Irregular galaxies (dIm) within 3.6 Mpc. The regions are identified on GALEX near-UV images, and modeled with UV, optical, and near-IR colors to determine masses and ages. A few galaxies have made 10^5-10^6 Msun complexes in a starburst phase, while others have not formed clusters in the last 50 Myrs. The maximum region mass correlates with the number of regions as expected from the size-of-sample effect. We find no radial gradients in region masses and ages, even beyond the realm of Halpha emission, although there is an exponential decrease in the luminosity density and number density of the regions with radius. Halpha is apparently lacking in the outer parts only because nebular emission around massive stars is too faint to see. The outermost regions for the 5 galaxies with HI data formed at average gas surface densities of 1.9-5.9 Msun/pc2. These low average densities imply either that local gas densities are high or sub-threshold star formation is possible. The distribution of regions on a log Mass - log age plot is is usually uniform along log age for equal intervals of log Mass. This uniformity results from either an individual region mass that varies as 1/age or a region disruption probability that varies as 1/age. A correlation between fading-corrected surface brightness and age suggests the former.Comment: Astronomical Journal, in press for November 2009. 34 pages, 18 figures, 5 table

    Bird-Window Collision MItigation at USU\u27s C&SS Building, Brigham City, Utah

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    Bird-window collisions are often not thought about as if they are a major problem to bird populations worldwide. This is not the case as bird populations are threatened by these collisions. In the United States alone it is estimated that 97.6 - 975.6 million birds fatally collide with human-made windows annually, and another 16 to 42 million collide in Canada per year. Our focus is to investigate a possible window collision problem and explore different mitigation efforts to prevent these collisions at the USU-Brigham City campus (Brigham City, Utah, 84302). We hope to determine how many fatal bird-window collisions are occurring on an annual basis. We are completing a daily census and already have data from previous years; however, those data cover only August to December, so our census will run for 12 months. Once enough information and data are collected, we plan to determine which types of mitigation efforts work best given the climate, location and behaviors of the local bird populations. We predict that large open windows with foliage nearby to be hotspots given previous data. These hotspots will be important locations to test out different mitigation efforts to be able to determine what works best to mitigate fatal bird window-collisions. When this is complete we plan to test the effects of our mitigation efforts by continuing the census. We also plan to educate the community on how to prevent these collisions at their own homes as more than 50 percent of collisions are on residential properties.https://digitalcommons.usu.edu/fsrs2020/1046/thumbnail.jp

    Structures of bacterial kynurenine formamidase reveal a crowded binuclear zinc catalytic site primed to generate a potent nucleophile

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    Tryptophan is an important precursor for chemical entities that ultimately support the biosynthesis of key metabolites. The second stage of tryptophan catabolism is catalysed by kynurenine formamidase, an enzyme that is different between eukaryotes and prokaryotes. In the present study, we characterize the catalytic properties and present the crystal structures of three bacterial kynurenine formamidases. The structures reveal a new amidase protein fold, a highly organized and distinctive binuclear Zn2+ catalytic centre in a confined, hydrophobic and relatively rigid active site. The structure of a complex with 2-aminoacetophenone delineates aspects of molecular recognition extending to the observation that the substrate itself may be conformationally restricted to assist binding in the confined space of the active site and for subsequent processing. The cations occupy a crowded environment, and, unlike most Zn2+ -dependent enzymes, there is little scope to increase co-ordination number during catalysis.We propose that the presence of a bridging water/hydroxide ligand in conjunction with the placement of an active site histidine supports a distinctive amidation mechanism.</p

    The isolation of differentially expressed cDNA clones from the filarial nematode <i>Brugia pahangi</i>

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    A cDNA library constructed from 3 day post-infective L3 of the filarial nematode Brugia pahangi was screened by differential hybridization with cDNA probes prepared from different life-cycle stages. Five cDNA clones hybridizing selectively to the mosquito-derived L3 probe were isolated and characterized. Northern blot analysis of 4 of the clones confirmed that each was most highly expressed in the mosquito-derived L3. The expression of each mRNA during parasite development in the mosquito vector was investigated using RT-PCR, and all were shown to be abundant in the immature L3. Four of the 5 cDNAs cloned coded for structural proteins: 2 cuticular collagens, and the muscle proteins tropomyosin and troponin. Further studies on troponin using an antiserum raised to the recombinant protein demonstrated that the protein, unlike the mRNA, was present in all life-cycle stages examined, while immunogold labelling demonstrated that it was localized to the muscle blocks

    Different forms of the bovine PrP gene have five or six copies of a short, G-C-rich element within the protein-coding exon

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    Current models of the virus-like agents of scrapie and bovine spongiform encephalopathy (BSE) have to take into account that structural changes in a host-encoded protein (PrP protein) exhibit an effect on the time course of these diseases and the survival time of any man or animal exposed to these pathogens. We report here the sequence of different forms of the bovine PrP gene which contain either five or six copies of a short, G-C-rich element which encodes the octapeptide Pro-His-Gly-Gly-Gly-Trp-Gly-Gln or its longer variants Pro-Gln/His-Gly-Gly-Gly-Gly-Trp-Gly-Gln. Out of 12 cattle, we found eight animals homozygous for genes with six copies of the Gly-rich peptide (6:6), while four were heterozygous (6:5). Two confirmed cases of BSE occurred in (6: 6) homozygous animals. Bovine spongiform encephalopathy (BSE) is a transmissible disease (Fraser et al., 1988; Dawson et al., 1990; Barlow &amp; Middleton, 1990) which produces neuropathological lesions in cattle similar to those seen in ovine scrapie (Wells et al., 1987) and the rare human dementias Creutzfeldt-Jakob disease (CJD) and Gerstmann-Str/iussler syndrome (GSS) (Beck &amp; Daniel, 1987). A cellular membrane protein (PrP) has a key role in the transmission and development of these diseases. This protein accumulates in the brain and other tissues during the protracted time course of these diseases and, in a disease-specific, protease-resistant isoform (SAF-PrP), has been purified by subcellular fractionation of scrapie

    Traces of the (un)familiar : family, identity, and the return of the repressed in the photographs of Ralph Eugene Meatyard.

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    This thesis explores the ways in which photographs by Ralph Eugene Meatyard provoke the uncanny—or Das unheimlich as Freud originally wrote in 1919—by breaking from conventions of mid-twentieth century family photography often utilized to establish and maintain genealogical unity. Meatyard’s photographs of his family and friends are accentuated by blurring techniques, prolonged exposures, and the incorporation of dime-store masks, and as a result depict moments when reality is disrupted by the return of repressed material from childhood. For a multitude of reasons, Meatyard’s photographs elicit comparisons to Surrealist photography as well as certain American modernists who also explored the notion of identity, such as Duane Michals, Van Deren Coke, and Minor White. Although he rarely left his home of Lexington, Kentucky, Meatyard was aware of the camera’s widespread use to produce and retain social myths. His photographs unveil these myths by incorporating elements that align with psychoanalytic theory
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