90 research outputs found

    Estuarine clay mineral distribution:Modern analogue for ancient sandstone reservoir quality prediction

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    The spatial distribution of clay minerals in sandstones, which may both enhance or degrade reservoir quality, is poorly understood. To address this, clay mineral distribution patterns and host‐sediment properties (grain size, sorting, clay fraction abundance and bioturbation intensity) have, for the first time, been determined and mapped at an unprecedentedly high‐resolution in a modern estuarine setting (Ravenglass Estuary, UK). Results show that the estuary sediment is dominated by illite with subordinate chlorite and kaolinite, although the rivers supply sediment with less illite and significantly more chlorite than found in the estuary. Fluvial‐supplied sediment has been locally diluted by sediment derived from glaciogenic drift deposits on the margins of the estuary. Detailed clay mineral maps and statistical analyses reveal that the estuary has a heterogeneous distribution of illite, chlorite and kaolinite. Chlorite is relatively most abundant on the northern foreshore and backshore and is concentrated in coarse‐grained inner estuary dunes and tidal bars. Illite is relatively most abundant (as well as most crystalline and most Fe–Mg‐rich) in fine‐grained inner estuary and central basin mud and mixed flats. Kaolinite has the highest abundance in fluvial sediment and is relatively homogenous in tidally‐influenced environments. Clay mineral distribution patterns in the Ravenglass Estuary have been strongly influenced by sediment supply (residence time) and subsequently modified by hydrodynamic processes. There is no relationship between macro‐faunal bioturbation intensity and the abundance of chlorite, illite or kaolinite. Based on this modern‐analogue study, outer estuarine sediments are likely to be heavily quartz cemented in deeply‐buried (burial temperatures exceeding 80 to 100°C) sandstone reservoirs due to a paucity of clay grade material (<0·5%) to form complete grain coats. In contrast, chlorite‐enriched tidal bars and dunes in the inner estuary, with their well‐developed detrital clay coats, are likely to have quartz cement inhibiting authigenic clay coats in deeply‐buried sandstones

    Investigation of autosomal genetic sex differences in Parkinson's disease

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    Objective: Parkinson's disease (PD) is a complex neurodegenerative disorder. Men are on average similar to 1.5 times more likely to develop PD compared to women with European ancestry. Over the years, genomewide association studies (GWAS) have identified numerous genetic risk factors for PD, however, it is unclear whether genetics contribute to disease etiology in a sex-specific manner.Methods: In an effort to study sex-specific genetic factors associated with PD, we explored 2 large genetic datasets from the International Parkinson's Disease Genomics Consortium and the UK Biobank consisting of 13,020 male PD cases, 7,936 paternal proxy cases, 89,660 male controls, 7,947 female PD cases, 5,473 maternal proxy cases, and 90,662 female controls. We performed GWAS meta-analyses to identify distinct patterns of genetic risk contributing to disease in male versus female PD cases.Results: In total, 19 genomewide significant regions were identified and no sex-specific effects were observed. A high genetic correlation between the male and female PD GWAS were identified (rg = 0.877) and heritability estimates were identical between male and female PD cases (similar to 20%).Interpretation: We did not detect any significant genetic differences between male or female PD cases. Our study does not support the notion that common genetic variation on the autosomes could explain the difference in prevalence of PD between males and females cases at least when considering the current sample size under study. Further studies are warranted to investigate the genetic architecture of PD explained by X and Y chromosomes and further evaluate environmental effects that could potentially contribute to PD etiology in male versus female patients.Neurological Motor Disorder

    Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.

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    BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362

    Analysis of shared heritability in common disorders of the brain

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    Paroxysmal Cerebral Disorder

    Origin and genetic structure of a recovering bobcat (Lynx rufus) population

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    Genetic analyses can provide important insights into the demographic processes that underlie recovering populations of mammals of conservation concern such as felid species. To better understand the recent and rapid recovery of bobcats (Lynx rufus [Schreber, 1777]) in Ohio, we analyzed samples from 4 states in the lower Great Lakes Region using 12 microsatellite DNA loci and a portion of the mtDNA control region. Our results showed that a newly-established population of bobcats in the eastern part of Ohio was genetically distinct from a multi-state population distributed across Kentucky, southern Ohio, West Virginia, and western Pennsylvania. There was no direct genetic evidence of a bottleneck or inbreeding in this population. A lack of private alleles and only slightly lower levels of allelic richness and heterozygosity compared to its neighbors suggest that the eastern Ohio population likely originated from the migration of relatively large numbers of individuals from a source population rather than re-emerging from an undetected residual population. We recommend that a management plan should define the areas occupied by the two populations in Ohio as separate management units at least for the near future.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

    Is there a link between childhood trauma, cognition, and amygdala and hippocampus volume in first-episode psychosis?

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    Patients with psychosis have higher rates of childhood trauma, which is also associated with adverse effects on cognitive functions such as attention, concentration and mental speed, language, and verbal intelligence. Although the pathophysiological substrate for this association remains unclear, these cognitive deficits may represent the functional correlate of changes observed in relation to trauma exposure in structures such as the amygdala and the hippocampus. Interestingly, these structures are often reported as altered in psychosis. This study investigated the association between childhood trauma, cognitive function and amygdala and hippocampus volume, in first-episode psychosis. We investigated 83 patients with first-episode psychosis and 63 healthy controls. All participants underwent an MRI scan acquired with a GE Sigma 1.5-T system, and a standardized neuropsychological assessment of general cognition, memory, processing speed, executive function, visuo-spatial abilities, verbal intelligence, and language. In a subsample of the patients (N=45) information on childhood trauma was collected with the Childhood Experience of Care and Abuse Questionnaire (CECA.Q). We found that amygdala, but not hippocampus, volume was significantly smaller (p=0.001) in patients compared to healthy controls. There was a trend level interaction for hippocampus volume between group and sex (p=0.056). A history of childhood trauma was associated with both worse cognitive performance and smaller amygdala volume. This smaller amygdala appeared to mediate the relationship between childhood trauma and performance on executive function, language and verbal intelligence in patients with psychosis. This points to a complex relationship between childhood trauma exposure, cognitive function and amygdala volume in first-episode psychosi
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