967 research outputs found

    Bowel necrosis associated with enteral feeding

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    Abstract from Clinical Nutrition Week, Dallas, TX, February 12-15, 2006

    Design and Implementation of a Studio-Based General Chemistry Course

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    Most students taking general chemistry courses do not intend to pursue careers in chemistry; in fact, they are more likely to end up in positions where they fund, write, or vote for chemical research and policies. Our profession continues to ask how we can teach students scientific reasoning skills and chemical understanding in general chemistry that they are able to take beyond the classroom into their everyday lives. The emerging answer at this university is the studio teaching method, which incorporates the “best teaching and learning practices†recommended by chemical education research within an integrated lecture–lab technology-intensive environment. The design, implementation, and pedagogical rationale of studio general chemistry are described

    A common p73 polymorphism is associated with a reduced incidence of oesophageal carcinoma

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    The incidence of oesophageal adenocarcinoma is rising; to date, no susceptibility genes have been identified. p73, a novel p53 homologue, maps to chromosome 1p36, a region commonly deleted in oesophageal cancers. p73 shares some p53-like activity, but in addition, may also play a role in gastrointestinal epithelial inflammatory responses. A non-coding p73 polymorphism (denoted AT or GC) may be functionally significant. We investigated whether this polymorphism might play a role in the aetiopathogenesis of oesophageal cancer. This was a case–control, retrospective study. 84 cases of oesophageal cancer (25 squamous and 59 adenocarcinoma) and 152 normal population controls were genotyped for this polymorphism. Informative cases were examined for p73 LOH within the tumour. AT/AT homozygotes were significantly less prevalent in the oesophageal cancer population (1/84 = 1.2%) compared to controls (15/152 = 9.9%) (P < 0.02), corresponding to an odds ratio of 0.11 (95% C.I. 0.02–0.6, P < 0.02), or 9-fold reduced risk. Moreover, AT/AT homozygotes were significantly less frequent in the cancer population than would be expected under the Hardy–Weinberg hypothesis (P = 0.0099). LOH at the p73 locus was observed in 37.8% (14/37) of the AT/GC heterozygotes studied; in all cases there was loss of the AT allele. Our findings indicate that p73 AT/AT homozygotes appear to be protected against the development of oesophageal cancer. Clinically, this observation could have implications in aiding identification of high-risk Barrett's oesophagus patients.© 2001 Cancer Research Campaign  http://www.bjcancer.co

    Parameter Estimation and Application of Anisotropic Yield Criteria for Cylindrical Aluminum Extrusions: Theoretical Developments and Stereodic Measurements

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    Theoretical and experimental studies are presented to characterize the anisotropic plastic response under torsion loading of two nominally identical aluminum Al6061-T6 extruded round bars. Theoretical models are developed using isotropic (Von Mises 1913) and anisotropic (Barlat 1991) yield criteria, along with isotropic strain hardening formulae, to model post-yield behavior under simple torsion loading. For the case of simple shear loading, incremental plasticity theory is used to determine the theoretical elastic, plastic, and total shear strains. A set of experiments are performed to calibrate Barlat’s 1991 yield function. Several specimens are extracted at different orientations to the longitudinal direction of each round Al6061-T6 bar and tested under uniaxial tension and simple torsion to optimally determine all anisotropic (Barlat 1991) yield function parameters. During loading, Stereo Digital Image Correlation (DIC) is used to quantify surface deformations for the torsion experiments and a baseline tension specimen to identify and correct measurement anomalies. Results show the isotropic yield model either underestimates or overestimates the experimental shear strains for both extrusions. Conversely, results using the Barlat 1991 anisotropic yield criteria are in excellent agreement with experimental measurements for both extrusions. The presence of significant differences in the anisotropic parameters for nominally similar extrusions confirms that plastic anisotropy is essential for the accurate prediction of mechanical behavior in longitudinally extruded Al6061-T6 bar

    Segregation of Mn, Si, Al, and oxygen during the friction stir welding of DH36 steel

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    This work investigates the role of welding speed in elemental segregation of Mn, Si, Al, and oxygen during friction stir welding (FSW) in DH36 steel. The experimental work undertaken showed that when the speed of the FSW process exceeds 500 RPM with a traverse speed of 400 mm/min, then elemental segregation of Mn, Si, Al, and O occurred. The mechanism of this segregation is not fully understood; additionally, the presence of oxygen within these segregated elements needs investigation. This work examines the elemental segregation within DH36 steel by conducting heat treatment experiments on unwelded samples incrementally in the range of 1200–1500 °C and at cooling rates similar to that in FSW process. The results of heat treatments were compared with samples welded under two extremes of weld tool speeds, namely W1 low tool speeds (200 RPM with traverse speed of 100 mm/min) and W2 high tool speeds (550 RPM with traverse speed of 400 mm/min). The results from the heat treatment trials showed that segregation commences when the temperature exceeds 1400 °C and Mn, Si, Al, and oxygen segregation progress occurs at 1450 °C and at a cooling rate associated with acicular ferrite formation. It was also found that high rotational speeds exceeding 500 RPM caused localized melting at the advancing-trailing side of the friction stir-welded samples. The study aims to estimate peak temperature limits at which elemental segregation does not occur and hence prevent their occurrence in practice by applying the findings to the tool’s rotational and traverse speed that correspond to the defined temperature

    Efficacy of Online Training for Improving Camp Staff Competency

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    Preparing competent staff is a critical issue within the camp community. This quasi-experimental study examined the effectiveness of an online course for improving staff competency in camp healthcare practices among college-aged camp staff and a comparison group (N = 55). We hypothesized that working in camp would increase competency test scores due to opportunities for staff to experientially apply knowledge learned online. Hierarchical linear modeling was used to analyse the cross-level effects of a between-individuals factor (assignment to experimental or comparison group) and within-individual effects of time (pre-test, post-test #1, and post-test #2) on online course test scores. At post-test #2, the difference in average test scores between groups was ~30 points, with the treatment group scoring lower on average than the comparison group. Factors that may have influenced these findings are explored, including fatigue and the limited durability of online learning. Recommendations for research and practice are discussed

    Thermal history modeling of the H chondrite parent body

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    The cooling histories of individual meteorites can be empirically reconstructed by using ages from different radioisotopic chronometers with distinct closure temperatures. For a group of meteorites derived from a single parent body such data permit the reconstruction of the cooling history and properties of that body. Particularly suited are H chondrites because precise radiometric ages over a wide range of closure temperatures are available. A thermal evolution model for the H chondrite parent body is constructed by using all H chondrites for which at least three different radiometric ages are available. Several key parameters determining the thermal evolution of the H chondrite parent body and the unknown burial depths of the H chondrites are varied until an optimal fit is obtained. The fit is performed by an 'evolution algorithm'. Empirical data for eight samples are used for which radiometric ages are available for at least three different closure temperatures. A set of parameters for the H chondrite parent body is found that yields excellent agreement (within error bounds) between the thermal evolution model and empirical data of six of the examined eight chondrites. The new thermal model constrains the radius and formation time of the H chondrite parent body (possibly (6) Hebe), the initial burial depths of the individual H chondrites, the average surface temperature of the body, the average initial porosity of the material the body accreted from, and the initial 60Fe content of the H chondrite parent body.Comment: 16 pages, 7 figure

    Multi-Domain Cognitive Assessment of Male Mice Shows Space Radiation Is Not Harmful to High-Level Cognition and Actually Improves Pattern Separation

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    Astronauts on interplanetary missions - such as to Mars - will be exposed to space radiation, a spectrum of highly-charged, fast-moving particles that includes 56Fe and 28Si. Earth-based preclinical studies show space radiation decreases rodent performance in low- and some high-level cognitive tasks. Given astronaut use of touchscreen platforms during training and space flight and given the ability of rodent touchscreen tasks to assess functional integrity of brain circuits and multiple cognitive domains in a non-aversive way, here we exposed 6-month-old C57BL/6J male mice to whole-body space radiation and subsequently assessed them on a touchscreen battery. Relative to Sham treatment, 56Fe irradiation did not overtly change performance on tasks of visual discrimination, reversal learning, rule-based, or object-spatial paired associates learning, suggesting preserved functional integrity of supporting brain circuits. Surprisingly, 56Fe irradiation improved performance on a dentate gyrus-reliant pattern separation task; irradiated mice learned faster and were more accurate than controls. Improved pattern separation performance did not appear to be touchscreen-, radiation particle-, or neurogenesis-dependent, as 56Fe and 28Si irradiation led to faster context discrimination in a non-touchscreen task and 56Fe decreased new dentate gyrus neurons relative to Sham. These data urge revisitation of the broadly-held view that space radiation is detrimental to cognition

    Negotiating employability: migrant capitals and networking strategies for Zimbabwean highly skilled migrants in the UK

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    In this paper we focus on highly skilled migration from Zimbabwe to the UK, exploring these migrants’ social capital sources/structures and content. In doing so we pay attention to routes of migration and how they shape migrants’ networking capabilities and patterns. We further take a Bourdieusian perspective and explore the intersection between social capital and cultural capital in the process of migrants’ negotiation of employment opportunities, giving closer attention to how the distinctive habitus associated with being highly skilled migrants from Zimbabwe shape migrants’ attitudes towards work. By exploring the interplay between external processes and internalised structures, we bring to the fore the multiple positioning of our participants, who we see not as simply depending on social networks, but as complex actors whose negotiation of employability in the UK is shaped by various factors including intersecting aspects of differentiation
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