79 research outputs found

    Working Memory in Collegiate Athletes and Non-Athletes: A Comparison of Team-Sports Athletes, Solo-Sports Athletes, Frequent Exercisers and Infrequent Exercisers

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    Past research suggests that exercise is associated with improved working memory (WM) abilities, and that athletes have better executive functioning and WM skills than non-athletes. However, no studies to date have separated the effects of exercise from the effects of athletic participation when examining WM. This study had three primary goals: (1) to determine whether amateur college athletes have better auditory and visual WM than their non-athlete peers who exercise frequently and whether non-athlete frequent exercisers have better WM than non-athlete infrequent exercisers (2) to determine whether amateur participation in particular types of sports (team-based versus solo sports) corresponds to differences in auditory or visual WM, and (3) to examine whether gender plays a role in the relationships between exercise, athletic participation and WM. This study was a cross-sectional, correlational design that examined WM in men versus women college students divided into four groups (team-sports athletes, solo-sports athletes, frequent exercisers, and infrequent exercisers). 153 college students completed five tests of auditory (Digit Span subtest, PASAT) and visual (Spatial Span subtest, N-Back, WCST) WM. Collegiate men who participated in team-based sports outperformed collegiate men who participated in solo-sports in auditory WM. The two non-athlete groups (frequent and infrequent exercisers) earned scores between those of the two athlete groups. Male infrequent exercisers demonstrated better visual WM than the other three male athlete/exerciser groups. In contrast, neither athletic participation nor exercise affected collegiate women’s WM abilities. Our results did not support our hypothesis that all types of student athletes would exhibit better WM than students who exercise regularly but do not engage in competitive sports. Additionally, our data did not indicate that frequent exercise is associated with stronger WM skills than infrequent exercise in non-athlete college students. Participation in team-based sports was associated with better auditory WM skills than participation in solo sports, but this was only true for male, not female, athletes. Thus, gender was an important factor in delineating the relationships between exercise, athletic participation and WM

    Effects of plutonium dioxide encapsulation on the physico-chemical development of Portland cement blended grouts

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    The effects of alpha radiation on cementitious systems used for nuclear waste encapsulation, and the subsequent physico-chemical properties, have been subject to limited investigation comparative to the effects of gamma and neutron irradiations. This paper outlines an assessment of the impact of PuO2 incorporation on the bulk characteristics of BFS and PFA blended Portland cements, with specific focus on the microstructure, phase assemblage and the radiolysis of pore water. Cellulose was also added to the cements to investigate the effects of organics on these systems. Characterisation of the bulk phase assemblage and microstructure were completed using optical and scanning electron microscopy (SEM), x-ray diffraction (XRD), and thermogravimetric analysis (TGA). Gas evolution was measured to determine the radiolytic breakdown of pore solution. In all samples the PuO2 appeared well encapsulated, with good physical contact to the cement grout and no large scale defects observed. Pu-containing hydrates were not observed, but PuO2 containing BFS based systems showed variations in the ratio of sulfate-containing phases, with increased ettringite observed. Gas evolution results were consistent with expectations based on likely radiation deposition, and increased G(H2) values were observed for cellulose containing samples. The findings of this study suggest the investigated cements are suitable encapsulants matrices for wastes containing PuO2

    Climate change implications for tidal marshes and food web linkages to estuarine and coastal nekton

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    Climate change is altering naturally fluctuating environmental conditions in coastal and estuarine ecosystems across the globe. Departures from long-term averages and ranges of environmental variables are increasingly being observed as directional changes [e.g., rising sea levels, sea surface temperatures (SST)] and less predictable periodic cycles (e.g., Atlantic or Pacific decadal oscillations) and extremes (e.g., coastal flooding, marine heatwaves). Quantifying the short- and long-term impacts of climate change on tidal marsh seascape structure and function for nekton is a critical step toward fisheries conservation and management. The multiple stressor framework provides a promising approach for advancing integrative, cross-disciplinary research on tidal marshes and food web dynamics. It can be used to quantify climate change effects on and interactions between coastal oceans (e.g., SST, ocean currents, waves) and watersheds (e.g., precipitation, river flows), tidal marsh geomorphology (e.g., vegetation structure, elevation capital, sedimentation), and estuarine and coastal nekton (e.g., species distributions, life history adaptations, predator-prey dynamics). However, disentangling the cumulative impacts of multiple interacting stressors on tidal marshes, whether the effects are additive, synergistic, or antagonistic, and the time scales at which they occur, poses a significant research challenge. This perspective highlights the key physical and ecological processes affecting tidal marshes, with an emphasis on the trophic linkages between marsh production and estuarine and coastal nekton, recommended for consideration in future climate change studies. Such studies are urgently needed to understand climate change effects on tidal marshes now and into the future

    Mutagenicity of tamoxifen DNA adducts in human endometrial cells and in silico prediction of p53 mutation hotspots

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    Tamoxifen elevates the risk of endometrial tumours in women and α-(N2-deoxyguanosinyl)-tamoxifen adducts are reportedly present in endometrial tissue of patients undergoing therapy. Given the widespread use of tamoxifen there is considerable interest in elucidating the mechanisms underlying treatment-associated cancer. Using a combined experimental and multivariate statistical approach we have examined the mutagenicity and potential consequences of adduct formation by reactive intermediates in target uterine cells. pSP189 plasmid containing the supF gene was incubated with α-acetoxytamoxifen or 4-hydroxytamoxifen quinone methide (4-OHtamQM) to generate dG-N2-tamoxifen and dG-N2-4-hydroxytamoxifen, respectively. Plasmids were replicated in Ishikawa cells then screened in Escherichia coli. Treatment with both α-acetoxytamoxifen and 4-OHtamQM caused a dose-related increase in adduct levels, resulting in a damage-dependent increase in mutation frequency for α-acetoxytamoxifen; 4-OHtamQM had no apparent effect. Only α-acetoxytamoxifen generated statistically different supF mutation spectra relative to the spontaneous pattern, with most mutations being GC→TA transversions. Application of the LwPy53 algorithm to the α-acetoxytamoxifen spectrum predicted strong GC→TA hotspots at codons 244 and 273. These signature alterations do not correlate with current reports of the mutations observed in endometrial carcinomas from treated women, suggesting that dG-N2-tam adduct formation in the p53 gene is not a prerequisite for endometrial cancer initiation in women

    The Separation of 241

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    Electrical power sources used in outer planet missions are a key enabling technology for data acquisition and communications. State–of-the-art power sources generate electricity from alpha decay of 238Pu via thermoelectric conversion. However, production of 238Pu requires specialist facilities including a nuclear reactor, a source of 237Np for target irradiation and hotcells to chemically separate neptunium and plutonium within the irradiated targets. These specialist facilities are expensive to build and operate, so naturally, a more economical alternative is attractive to the industry. Within Europe 241Am is considered a promising alternative heat source for radioisotope thermoelectric generators (RTGs) and radioisotope heating units (RHUs). As a daughter product of 241Pu decay, 241Am exists in 1000 kgs quantities within the UK civil plutonium stockpile. A chemical separation process is required to extract the 241Am in a pure form and this paper describes the AMPPEX process (Americium and Plutonium Purification by Extraction), successfully developed over the past five years to isolate 241Am in high yield (> 99%) and to a high purity (> 99%). The process starts by dissolving plutonium dioxide in nitric acid with the aid of a silver(II) catalyst, which is generated electrochemically. The solution is then conditioned and fed to a PUREX type solvent extraction process, where the plutonium is separated from the americium and silver. The plutonium is converted back to plutonium dioxide and the americium is fed forward to a second solvent extraction step. Here the americium is selectively extracted leaving the silver in the aqueous phase. The americium is stripped from the solvent and recovered from solution as americium oxalate, which is calcined to give americium dioxide as the final product. This paper will describe the development of the separation process over a series of six solvent extraction separation trials using centrifugal contactors. The material produced (~ 4g 241Am) was used to make ceramic pellets to establish the behaviour of americium oxide material under high temperature (1450°C) sintering conditions. The chemical separation process is now demonstrated at concentrations expected on the full scale facility taking this process to TRL 4-5

    The FuturICT education accelerator

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    Education is a major force for economic and social wellbeing. Despite high aspirations, education at all levels can be expensive and ineffective. Three Grand Challenges are identified: (1) enable people to learn orders of magnitude more effectively, (2) enable people to learn at orders of magnitude less cost, and (3) demonstrate success by exemplary interdisciplinary education in complex systems science. A ten year ‘man-on-the-moon’ project is proposed in which FuturICT’s unique combination of Complexity, Social and Computing Sciences could provide an urgently needed transdisciplinary language for making sense of educational systems. In close dialogue with educational theory and practice, and grounded in the emerging data science and learning analytics paradigms, this will translate into practical tools (both analytical and computational) for researchers, practitioners and leaders; generative principles for resilient educational ecosystems; and innovation for radically scalable, yet personalised, learner engagement and assessment. The proposed Education Accelerator will serve as a ‘wind tunnel’ for testing these ideas in the context of real educational programmes, with an international virtual campus delivering complex systems education exploiting the new understanding of complex, social, computationally enhanced organisational structure developed within FuturICT

    The FuturICT education accelerator

    Get PDF
    Education is a major force for economic and social wellbeing. Despite high aspirations, education at all levels can be expensive and ineffective. Three Grand Challenges are identified: (1) enable people to learn orders of magnitude more effectively, (2) enable people to learn at orders of magnitude less cost, and (3) demonstrate success by exemplary interdisciplinary education in complex systems science. A ten year ‘man-on-the-moon’ project is proposed in which FuturICT’s unique combination of Complexity, Social and Computing Sciences could provide an urgently needed transdisciplinary language for making sense of educational systems. In close dialogue with educational theory and practice, and grounded in the emerging data science and learning analytics paradigms, this will translate into practical tools (both analytical and computational) for researchers, practitioners and leaders; generative principles for resilient educational ecosystems; and innovation for radically scalable, yet personalised, learner engagement and assessment. The proposed Education Accelerator will serve as a ‘wind tunnel’ for testing these ideas in the context of real educational programmes, with an international virtual campus delivering complex systems education exploiting the new understanding of complex, social, computationally enhanced organisational structure developed within FuturICT

    Central venous catheter use in severe malaria: time to reconsider the World Health Organization guidelines?

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    <p>Abstract</p> <p>Background</p> <p>To optimize the fluid status of adult patients with severe malaria, World Health Organization (WHO) guidelines recommend the insertion of a central venous catheter (CVC) and a target central venous pressure (CVP) of 0-5 cmH<sub>2</sub>O. However there are few data from clinical trials to support this recommendation.</p> <p>Methods</p> <p>Twenty-eight adult Indian and Bangladeshi patients admitted to the intensive care unit with severe <it>falciparum </it>malaria were enrolled in the study. All patients had a CVC inserted and had regular CVP measurements recorded. The CVP measurements were compared with markers of disease severity, clinical endpoints and volumetric measures derived from transpulmonary thermodilution.</p> <p>Results</p> <p>There was no correlation between the admission CVP and patient outcome (p = 0.67) or disease severity (p = 0.33). There was no correlation between the baseline CVP and the concomitant extravascular lung water (p = 0.62), global end diastolic volume (p = 0.88) or cardiac index (p = 0.44). There was no correlation between the baseline CVP and the likelihood of a patient being fluid responsive (p = 0.37). On the occasions when the CVP was in the WHO target range patients were usually hypovolaemic and often had pulmonary oedema by volumetric measures. Seven of 28 patients suffered a complication of the CVC insertion, although none were fatal.</p> <p>Conclusion</p> <p>The WHO recommendation for the routine insertion of a CVC, and the maintenance of a CVP of 0-5 cmH<sub>2</sub>O in adults with severe malaria, should be reconsidered.</p

    Feline low-grade alimentary lymphoma: an emerging entity and a potential animal model for human disease

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    Background: Low-grade alimentary lymphoma (LGAL) is characterised by the infiltration of neoplastic T-lymphocytes, typically in the small intestine. The incidence of LGAL has increased over the last ten years and it is now the most frequent digestive neoplasia in cats and comprises 60 to 75% of gastrointestinal lymphoma cases. Given that LGAL shares common clinical, paraclinical and ultrasonographic features with inflammatory bowel diseases, establishing a diagnosis is challenging. A review was designed to summarise current knowledge of the pathogenesis, diagnosis, prognosis and treatment of feline LGAL. Electronic searches of PubMed and Science Direct were carried out without date or language restrictions. Results: A total of 176 peer-reviewed documents were identified and most of which were published in the last twenty years. 130 studies were found from the veterinary literature and 46 from the human medicine literature. Heterogeneity of study designs and outcome measures made meta-analysis inappropriate. The pathophysiology of feline LGAL still needs to be elucidated, not least the putative roles of infectious agents, environmental factors as well as genetic events. The most common therapeutic strategy is combination treatment with prednisolone and chlorambucil, and prolonged remission can often be achieved. Developments in immunohistochemical analysis and clonality testing have improved the confidence of clinicians in obtaining a correct diagnosis between LGAL and IBD. The condition shares similarities with some diseases in humans, especially human indolent T-cell lymphoproliferative disorder of the gastrointestinal tract. Conclusions: The pathophysiology of feline LGAL still needs to be elucidated and prospective studies as well as standardisation of therapeutic strategies are needed. A combination of conventional histopathology and immunohistochemistry remains the current gold-standard test, but clinicians should be cautious about reclassifying cats previously diagnosed with IBD to lymphoma on the basis of clonality testing. Importantly, feline LGAL could be considered to be a potential animal model for indolent digestive T-cell lymphoproliferative disorder, a rare condition in human medicine
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