801 research outputs found

    Sulfur constraints on the carbon cycle of a blanket bog peatland

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    The reduction of sulfate (SO42−) represents an alternative terminal electron acceptor for the oxidation of organic matter in peat soils. The greenhouse gas budget in peatlands will be constrained by how much a peatland can utilize SO42− reduction as an alternative to methanogenesis. Using records of atmospheric deposition and stream chemistry coupled with elemental analysis of peat soil, vegetation, particulate organic matter (POM) and dissolved organic matter (DOM), this study estimated a 23-years long sulfur (S) budget for a blanket bog-covered catchment in the North Pennines, England. The study showed that: (a) Atmospheric deposition of total S significantly declined over the study period from 2.4 to 0.5 t S/km2/yr. (b) Long term accumulation of S into deep peat at 1 m depth averaged 127 kg S/km2/yr. (c) Total S fluvial flux peaked as 4.5 t S/km2/yr with an average of 0.7 t S/km2/yr. (d) On average, over 23 years, 0.25 t S/km2/yr were reduced to either mineral sulphides or hydrogen sulphide; however, in eight out of the 23 years the catchment was a net producer of S to the streams of the catchment. At maximum observed, S reduction capacity the peatland was capable of a net removal of 71% of atmospheric S deposition. Allowing for the efficiency of energy transfer in the redox process and the oxidation state of peat organic matter means that for every mole of SO42− reduced, 1.69 moles of CO2 were produced, and an average of 0.47 t C/km2/yr are diverted from methanogenesis

    Electrophysiological correlates of reinforcement learning in young people with Tourette syndrome with and without co-occurring ADHD symptoms

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    Altered reinforcement learning is implicated in the causes of Tourette syndrome (TS) and attention-deficit/hyperactivity disorder (ADHD). TS and ADHD frequently co-occur but how this affects reinforcement learning has not been investigated. We examined the ability of young people with TS (n = 18), TS+ADHD (N = 17), ADHD (n = 13) and typically developing controls (n = 20) to learn and reverse stimulus-response (S-R) associations based on positive and negative reinforcement feedback. We used a 2 (TS-yes, TS-no) x 2 (ADHD-yes, ADHD-no) factorial design to assess the effects of TS, ADHD, and their interaction on behavioural (accuracy, RT) and event-related potential (stimulus-locked P3, feedback-locked P2, feedback-related negativity, FRN) indices of learning and reversing the S-R associations. TS was associated with intact learning and reversal performance and largely typical ERP amplitudes. ADHD was associated with lower accuracy during S-R learning and impaired reversal learning (significantly reduced accuracy and a trend for smaller P3 amplitude). The results indicate that co-occurring ADHD symptoms impair reversal learning in TS+ADHD. The implications of these findings for behavioural tic therapies are discussed

    An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics

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    For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types
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