908 research outputs found
Methane anomalies over TAG hydrothermal field on Mid Atlantic Ridge
Black smoker type hydrothermal venting was discovered in July 1985 at the TAG hydrothermal field in the rift valley of the Mid Atlantic Ridge near 26N. We present here, the first methane profiles in the seawater column over this black smoker along with methane profiles away from the black smokers for comparison. The CH4 plume, spreading over 400 m above the seafloor, shows a maximum concentration of 105 nl/l at 3450 m (238 m above the bottom), correlated with a positive temperature anomaly (0.02°C). CH4 concentrations up to 2422 nl/l, correlated with a huge positive increase of in situ temperature (0.349°C), have been measured in samples taken 5 m above the sea floor, showing an important CH4 input in this slow spreading site which is similar to inputs from fast spreading sites like the East Pacific Rise
Considerations for Individual-Level Versus Whole-School Physical Activity Interventions:Stakeholder Perspectives
Strategies to address declining physical activity levels among children and adolescents have focused on âindividual-levelâ approaches which often fail to demonstrate impact. Recent attention has been on an alternative âwhole-schoolâ approach to increasing physical activity that involves promoting physical activity throughout all aspects of the school environment. There is, however, a lack of evidence on how whole-school physical activity approaches could be implemented in the UK. This qualitative study explored perspectives of key stakeholders on potential reasons for the lack of impact of individual-level school-based interventions on childrenâs physical activity, and key considerations for adopting a whole-school approach. Nineteen semi-structured interviews were conducted with a range of stakeholders involved in the implementation of physical activity programmes in UK schools. Data were analysed using an inductive approach. Respondents suggested that individual-level school-based interventions to increase physical activity often failed to consult end users in the design and were typically implemented in environments unsupportive of long-term change. They subsequently outlined specific barriers and key facilitators for the adoption and implementation of whole-school approaches in UK settings and recommended a shift in research foci towards building an evidence base around educational outcomes and whole-school implementation insights
Genetic Variation in the ASTN2 Locus in Cardiovascular, Metabolic and Psychiatric Traits: Evidence for Pleiotropy Rather Than Shared Biology
Background: The link between cardiometabolic and psychiatric illness has long been attributed to human behaviour, however recent research highlights shared biological mechanisms. The ASTN2 locus has been previously implicated in psychiatric and cardiometabolic traits, therefore this study aimed to systematically investigate the genetic architecture of ASTN2 in relation to a wide range of relevant traits. Methods: Baseline questionnaire, assessment and genetic data of 402111 unrelated white British ancestry individuals from the UK Biobank was analysed. Genetic association analyses were conducted using PLINK 1.07, assuming an additive genetic model and adjusting for age, sex, genotyping chip, and population structure. Conditional analyses and linkage disequilibrium assessment were used to determine whether cardiometabolic and psychiatric signals were independent. Results: Associations between genetic variants in the ASTN2 locus and blood pressure, total and central obesity, neuroticism, anhedonia and mood instability were identified. All analyses support the independence of the cardiometabolic traits from the psychiatric traits. In silico analyses provide support for the central obesity signal acting through ASTN2, however most of the other signals are likely acting through other genes in the locus. Conclusions: Our systematic analysis demonstrates that ASTN2 has pleiotropic effects on cardiometabolic and psychiatric traits, rather than contributing to shared pathology
How many mailouts? Could attempts to increase the response rate in the Iraq war cohort study be counterproductive?
<p>Abstract</p> <p>Background</p> <p>Low response and reporting errors are major concerns for survey epidemiologists. However, while nonresponse is commonly investigated, the effects of misclassification are often ignored, possibly because they are hard to quantify. We investigate both sources of bias in a recent study of the effects of deployment to the 2003 Iraq war on the health of UK military personnel, and attempt to determine whether improving response rates by multiple mailouts was associated with increased misclassification error and hence increased bias in the results.</p> <p>Methods</p> <p>Data for 17,162 UK military personnel were used to determine factors related to response and inverse probability weights were used to assess nonresponse bias. The percentages of inconsistent and missing answers to health questions from the 10,234 responders were used as measures of misclassification in a simulation of the 'true' relative risks that would have been observed if misclassification had not been present. Simulated and observed relative risks of multiple physical symptoms and post-traumatic stress disorder (PTSD) were compared across response waves (number of contact attempts).</p> <p>Results</p> <p>Age, rank, gender, ethnic group, enlistment type (regular/reservist) and contact address (military or civilian), but not fitness, were significantly related to response. Weighting for nonresponse had little effect on the relative risks. Of the respondents, 88% had responded by wave 2. Missing answers (total 3%) increased significantly (p < 0.001) between waves 1 and 4 from 2.4% to 7.3%, and the percentage with discrepant answers (total 14%) increased from 12.8% to 16.3% (p = 0.007). However, the adjusted relative risks decreased only slightly from 1.24 to 1.22 for multiple physical symptoms and from 1.12 to 1.09 for PTSD, and showed a similar pattern to those simulated.</p> <p>Conclusion</p> <p>Bias due to nonresponse appears to be small in this study, and increasing the response rates had little effect on the results. Although misclassification is difficult to assess, the results suggest that bias due to reporting errors could be greater than bias caused by nonresponse. Resources might be better spent on improving and validating the data, rather than on increasing the response rate.</p
Among friends:A qualitative exploration of the role of peers in young people's alcohol use using Bourdieuâs concepts of habitus, field and capital
Drinking is viewed by young people as a predominantly social activity which provides an opportunity for entertainment and bonding with friends. Using Bourdieu's concepts of habitus, field and capital, this article explores young people's attitudes and beliefs around alcohol use, influences on behaviour, and the role of peers, with a view to informing the development of preventive interventions. Semi-structured interviews were conducted with 28 young people aged 18â20 in the south west of England. We describe how friends were integral in drinking experiences, and drinking with friends was equated with fun and enjoyment. In this way, the desire for social and symbolic capital appeared to be a key motivator for adolescent drinking. Critically, however, wider cultural norms played the predominant role in shaping behaviour, via the internalisation of widely accepted practice and the subsequent externalisation of norms through the habitus. Applying Bourdieu's theory suggests that population-level interventions that regulate alcohol consumption, and thus disrupt the field, are likely to facilitate behaviour change among young people by driving a response in habitus
Methods applied to neonatal dried blood spot samples for secondary research purposes:a scoping review
This scoping review aimed to synthesize the analytical techniques used and methodological limitations encountered when undertaking secondary research using residual neonatal dried blood spot (DBS) samples. Studies that used residual neonatal DBS samples for secondary research (i.e. research not related to newborn screening for inherited genetic and metabolic disorders) were identified from six electronic databases: Cochrane Library, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Embase, Medline, PubMed and Scopus. Inclusion was restricted to studies published from 1973 and written in or translated into English that reported the storage, extraction and testing of neonatal DBS samples. Sixty-seven studies were eligible for inclusion. Included studies were predominantly methodological in nature and measured various analytes, including nucleic acids, proteins, metabolites, environmental pollutants, markers of prenatal substance use and medications. Neonatal DBS samples were stored over a range of temperatures (ambient temperature, cold storage or frozen) and durations (two weeks to 40.5âyears), both of which impacted the recovery of some analytes, particularly amino acids, antibodies and environmental pollutants. The size of DBS sample used and potential contamination were also cited as methodological limitations. Residual neonatal DBS samples retained by newborn screening programs are a promising resource for secondary research purposes, with many studies reporting the successful measurement of analytes even from neonatal DBS samples stored for long periods of time in suboptimal temperatures and conditions.</p
Marine mineral exploration with controlled source electromagnetics at the TAG Hydrothermal Field, 26°N MidâAtlantic Ridge
Seafloor massive sulfide (SMS) deposits are of increasing economic interest in order to satisfy the relentless growth in worldwide metal demand. The TransâAtlantic Geotraverse (TAG) hydrothermal field at 26°N on the MidâAtlantic Ridge hosts several such deposits. This study presents new controlled source electromagnetic, bathymetric, and magnetic results from the TAG field. Potential SMS targets were selected based on their surface expressions in highâresolution bathymetric data. Highâresolution reducedâtoâtheâpole magnetic data show negative anomalies beneath and surrounding the SMS deposits, revealing large areas of hydrothermal alteration. Controlled source electromagnetic data, sensitive to the electrical conductivity of SMS mineralization, further reveal a maximum thickness of up to 80 m and conductivities of up to 5 S/m. SMS samples have conductivities of up to a few thousand Siemens per meter, suggesting that remotely inferred conductivities represent an average of metal sulfide ores combined with silicified and altered host basalt that likely dominates at greater depths
Acceleration of global NâO emissions seen from two decades of atmospheric inversion
Nitrous oxide (N2O) is the third most important long-lived GHG and an important stratospheric ozone depleting substance. Agricultural practices and the use of N-fertilizers have greatly enhanced emissions of N2O. Here, we present estimates of N2O emissions determined from three global atmospheric inversion frameworks during the period 1998â2016. We find that global N2O emissions increased substantially from 2009 and at a faster rate than estimated by the IPCC emission factor approach. The regions of East Asia and South America made the largest contributions to the global increase. From the inversion-based emissions, we estimate a global emission factor of 2.3â±â0.6%, which is significantly larger than the IPCC Tier-1 default for combined direct and indirect emissions of 1.375%. The larger emission factor and accelerating emission increase found from the inversions suggest that N2O emission may have a nonlinear response at global and regional scales with high levels of N-input
Assessing for interaction between APOE Δ4, sex and lifestyle on cognitive abilities
Objective: To test for interactions between APOE Δ4 genotype and lifestyle factors on worse cognitive abilities in UK Biobank.
Methods: Using UK Biobank cohort data, we tested for interactions between APOE Δ4 allele presence, lifestyle factors of alcohol intake, smoking, total physical activity and obesity, and sex, on cognitive tests of reasoning, information processing speed, and executive function (n range = 70,988â324,725 depending on the test). We statistically adjusted for potential confounders of age, sex, deprivation, cardiometabolic conditions, and educational attainment.
Results: There were significant associations between APOE Δ4 and worse cognitive abilities, independent of potential confounders, and between lifestyle risk factors and worse cognitive abilities; however, there were no interactions at multiple correction-adjusted p < 0.05, against our hypotheses.
Conclusions: Our results do not provide support for the idea that Δ4 genotype increases vulnerability to the negative effects of lifestyle risk factors on cognitive ability, but rather support a primarily outright association between APOE Δ4 genotype and worse cognitive ability
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