1,784 research outputs found

    Complex Factors in the Etiology of Gulf War Illness: Wartime Exposures and Risk Factors in Veteran Subgroups

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    Background: At least one-fourth of U.S. veterans who served in the 1990ā€“1991 Gulf War are affected by the chronic symptomatic illness known as Gulf War illness (GWI). Clear determination of the causes of GWI has been hindered by many factors, including limitations in how epidemiologic studies have assessed the impact of the complex deployment environment on veteransā€™ health

    Butyrylcholinesterase genotype and enzyme activity in relation to Gulf War illness: preliminary evidence of gene-exposure interaction from a caseĀæcontrol study of 1991 Gulf War veterans

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    Abstract Background Epidemiologic studies have implicated wartime exposures to acetylcholinesterase (AChE)-inhibiting chemicals as etiologic factors in Gulf War illness (GWI), the multisymptom condition linked to military service in the 1991 Gulf War. It is unclear, however, why some veterans developed GWI while others with similar exposures did not. Genetic variants of the enzyme butyrylcholinesterase (BChE) differ in their capacity for metabolizing AChE-inhibiting chemicals, and may confer differences in biological responses to these compounds. The current study assessed BChE enzyme activity and BChE genotype in 1991 Gulf War veterans to evaluate possible association of this enzyme with GWI. Methods This case–control study evaluated a population-based sample of 304 Gulf War veterans (144 GWI cases, meeting Kansas GWI criteria, and 160 controls). BChE enzyme activity levels and genotype were compared, overall, in GWI cases and controls. Potential differences in risk associated with cholinergic-related exposures in theater were explored using stratified analyses to compare associations between GWI and exposures in BChE genetic and enzyme activity subgroups. Results Overall, GWI cases and controls did not differ by mean BChE enzyme activity level or by BChE genotype. However, for the subgroup of Gulf War veterans with less common, generally less active, BChE genotypes (K/K, U/AK, U/A, A/F, AK/F), the association of wartime use of pyridostigmine bromide (PB) with GWI (OR = 40.00, p = 0.0005) was significantly greater than for veterans with the more common U/U and U/K genotypes (OR = 2.68, p = 0.0001). Conclusions Study results provide preliminary evidence that military personnel with certain BChE genotypes who used PB during the 1991 Gulf War may have been at particularly high risk for developing GWI. Genetic differences in response to wartime exposures are potentially important factors in GWI etiology and should be further evaluated in conjunction with exposure effects.Peer Reviewe

    Reclaiming literacies: competing textual practices in a digital higher education

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    This essay examines the implications of the ubiquitous use of the term ā€˜digital literaciesā€™ in higher education and its increasing alignment with institutional and organisational imperatives. It suggests that the term has been stripped of its provenance and association with disciplinary knowledge production and textual practice. Instead it is called into service rhetorically in order to promote competency based agendas both in and outside the academy. The piece also points to a tendency to position teachers in deficit with regard to their technological capabilities and pay scant attention to their own disciplinary and scholarly practices in a digital world. It concludes that there is a case for building on established theoretical and conceptual frameworks from literacy studies if we wish to integrate advantages of the digital landscape with thoughtful teaching practice

    New insights into the cardiorespiratory physiology of weaned southern elephant seals (Mirounga leonina)

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    Southern elephant seal (Mirounga leonina) pups must strike a balance between conserving energy during their post-weaning fast and simultaneously developing diving abilities to attain nutritional independence. Little is known about environmental influences on cardiorespiratory patterns, hence energy use, throughout the 6ā€…week fast. Continuous heart rates were recorded for free-ranging, newly weaned southern elephant seals using heart rate time-depth recorders for 5-9ā€…days at Sub-Antarctic Macquarie Island, during October 1994 (nā€…=ā€…1), 1995 (nā€…=ā€…4) and 1996 (nā€…=ā€…1). Daytime observations of respiration and behaviour were made throughout. We present the first instance of synchronous heart rate traces recorded simultaneously for individual weaners. Generalized additive models revealed that a sinusoidal pattern of diurnal heart rate elevation and nocturnal depression was evident in all seals and, on at least one occasion, a conspicuous break in this pattern coincided with an extreme cold weather event. Seals in this study were capable of considerable cardiorespiratory control and regularly demonstrated bradycardia during periods of resting apnoea. Apnoeic duration ranged from 33 to 291ā€…s (mean 134ā€…s). Apnoeic heart rates (mean 67ā€…±ā€…15ā€…beatsā€…min(-1), range 40-114ā€…beatsā€…min(-1)) were on average 19.7% lower than those exhibited during periods of eupnoea (mean 83ā€…±ā€…15ā€…beatsā€…min(-1), range 44-124ā€…beatsā€…min(-1)). The early development of the cardiorespiratory response is characterized by arrhythmic heart and respiration rates. The strong temporal patterns observed are being driven by the opposing requirements of maximizing time spent fasting in order to develop diving capabilities and of maximizing departure mass. This pilot study has highlighted a potentially large effect of ambient weather conditions on newly weaned southern elephant seal cardiorespiratory activity. Given the increasing westerlies and more erratic and increasing storminess associated with the Southern Annular Mode predicted in the Southern Ocean, the patterns observed here warrant further investigation

    North Atlantic ecosystem sensitivity to Holocene shifts in Meridional Overturning Circulation

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    Rapid changes in North Atlantic climate over the last millennia were driven by coupled sea surface/atmospheric processes and rates of deep-water formation. Holocene climate changes, however, remain poorly documented due to a lack of high-resolution paleoclimate records, and their impacts on marine ecosystems remain unknown. We present a 4500 years absolute-dated sea surface radiocarbon record from northeast Atlantic cold-water corals. In contrast to the current view that surface ocean changes occurred on millennial-scale cycles, our record shows more abrupt changes in surface circulation. Changes were centered at 3.4, 2.7, 1.7 and 1.2 ky BP, and associated with atmospheric re-organization. Solar irradiance may have influenced these anomalies, but changes in North Atlantic deep-water convection are likely to have amplified these signals. Critically, we provide the first evidence that these perturbations in Atlantic Meridional Overturning Circulation led to the decline of cold-water coral ecosystems from 1.2 to ~ 0.1 ky BP

    Introduced species and extreme weather as key drivers of reproductive output in three sympatric albatrosses

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    Invasive species present a major conservation threat globally and nowhere are their affects more pronounced than in island ecosystems. Determining how native island populations respond demographically to invasive species can provide information to mitigate the negative effects of invasive species. Using 20 years of mark-recapture data from three sympatric species of albatrosses (black-browed Thalassarche melanophris, grey-headed T. chrysostoma, and light-mantled albatrosses Phoebetria palpebrata), we quantified the influence of invasive European rabbits Oryctolagus cuniculus and extreme weather patterns on breeding probability and success. Temporal variability in rabbit density explained 33ā€“76% of the variability in breeding probability for all three species, with severe decreases in breeding probability observed after a lag period following highest rabbit numbers. For black-browed albatrosses, the combination of extreme rainfall and high rabbit density explained 33% of total trait variability and dramatically reduced breeding success. We showed that invasive rabbits and extreme weather events reduce reproductive output in albatrosses and that eliminating rabbits had a positive effect on albatross reproduction. This illustrates how active animal management at a local breeding site can result in positive population outcomes even for wide ranging animals like albatrosses where influencing vital rates during their at-sea migrations is more challenging
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