240 research outputs found

    Lithostratigraphy, biostratigraphy, and stable-isotope stratigraphy of cores from ODP Leg 105 site surveys, Labrador Sea and Baffin Bay

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    Trigger weight (TWC) and piston (PC) cores obtained from surveys of the three sites drilled during Ocean Drilling Program (ODP) Leg 105 were studied in detail for benthic foraminiferal assemblages, total carbonate (all sites), planktonic foraminiferal abundances (Sites 645 and 647), and stable isotopes (Sites 646 and 647). These high-resolution data provide the link between modern environmental conditions represented by the sediment in the TWC and the uppermost cores of the ODP holes. This link provides essential control data for interpretating late Pleistocene paleoceanographic records from these core holes. At Site 645 in Baffin Bay, local correlation is difficult because the area is dominated by ice-rafted deposits and by debris flows and/or turbidite sedimentation. At the two Labrador Sea sites (646 and 647), the survey cores and uppermost ODP cores can be correlated. High-resolution data from the site survey cores also provide biostratigraphic data that refine the interpretations compiled from core-catcher samples at each ODP site

    Creation of a universal experimental protocol for the investigation of transfer and persistence of trace evidence:Part 1 - From design to implementation for particulate evidence

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    Understanding the transfer and persistence of different types of trace evidence between different donor and receiving surfaces under specific conditions, circumstances and alleged competing defence and prosecution hypotheses is a significant need. Acquiring such a knowledge base enables hypothesis testing to be undertaken more readily and with greater confidence. A longstanding goal has been to develop a unified approach to transfer and persistence studies which are fit for purpose but also scalable.Here we propose a low cost, universal experimental protocol using a recognised and well researched proxy material for the development and aggregation of ground truth transfer and persistence data at scale. We also propose and provide the tools to enable the creation of an open source and open access data repository of experimental data to act as a resource for practitioners and researchers in addressing transfer and persistence questions

    How Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) progresses. The natural history of ME/CFS

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    We propose a framework for understanding and interpreting the pathophysiology of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) that considers wider determinants of health and long-term temporal variation in pathophysiological features and disease phenotype throughout the natural history of the disease. As in other chronic diseases, ME/CFS evolves through different stages, from asymptomatic predisposition, progressing to a prodromal stage, and then to symptomatic disease. Disease incidence depends on genetic makeup and environment factors, the exposure to singular or repeated insults, and the nature of the host response. In people who develop ME/CFS, normal homeostatic processes in response to adverse insults may be replaced by aberrant responses leading to dysfunctional states. Thus, the predominantly neuro-immune manifestations, underlined by a hyper-metabolic state, that characterize early disease, may be followed by various processes leading to multi-systemic abnormalities and related symptoms. This abnormal state and the effects of a range of mediators such as products of oxidative and nitrosamine stress, may lead to progressive cell and metabolic dysfunction culminating in a hypometabolic state with low energy production. These processes do not seem to happen uniformly; although a spiraling of progressive inter-related and self-sustaining abnormalities may ensue, reversion to states of milder abnormalities is possible if the host is able to restate responses to improve homeostatic equilibrium. With time variation in disease presentation, no single ME/CFS case description, set of diagnostic criteria, or molecular feature is currently representative of all patients at different disease stages. While acknowledging its limitations due to the incomplete research evidence, we suggest the proposed framework may support future research design and health care interventions for people with ME/CFS

    Atlas of modern dinoflagellate cyst distributions in the Black Sea Corridor: From Aegean to Aral Seas, including Marmara, Black, Azov and Caspian Seas

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    We present the first comprehensive taxonomic and environmental study of dinoflagellate cysts in 185 surface sediment samples from the Black Sea Corridor (BSC) which is a series of marine basins extending from the Aegean to the Aral Seas (including Marmara, Black, Azov and Caspian Seas). For decades, these low-salinity, semi-enclosed or endorheic basins have experienced large-scale changes because of intensive agriculture and industrialisation, with consequent eutrophication and increased algal blooms. The BSC atlas data provide a baseline for improved understanding of linkages between surface water conditions and dinoflagellate cyst (dinocyst) distribution, diversity and morphological variations. By cross-reference to dinocyst occurrences in sediment cores with radiocarbon ages covering the past c. 11,700 years, the history of recent biodiversity changes can be evaluated. The seabed cyst samples integrate seasonal and multi-year data which are not usually captured by plankton samples, and the cyst composition can point to presence of previously unrecorded motile dinoflagellate species in the BSC. Results show the presence of at least 71 dinocyst taxa of which 36% can be related to motile stages recorded in the plankton. Comparison with sediment core records shows that five new taxa appear to have entered or re-entered the region over the past century. Statistical analysis of the atlas data reveals the presence of four ecological assemblages which are primarily correlated with seasonal and annual surface water salinity and temperature; correlation with phosphate, nitrate and silicate nutrients, chlorophyll-a and bottom water oxygen is less clear but may be important for some taxa. Biodiversity indices reveal strong west − east biogeographical differences among the basins that reflect the different histories of Mediterranean versus Ponto-Caspian connections. The atlas data provide a standardised taxonomy and regional database for interpreting downcore cyst variations in terms of quantitative oceanographic changes. The atlas also provides a baseline for monitoring further changes in the BSC dinocysts that may accompany the accelerating development of the region

    Creation of a universal experimental protocol for the investigation of transfer and persistence of trace evidence:Part 2 – Implementation and preliminary data

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    This is the second paper on the development and implementation of a universal experimental protocol for transfer and persistence of trace evidence. Here, we present the results of five individual researchers who implemented the universal experimental protocol for the first time. Over 2500 images were collected, computationally analysed and statistically compared. The results were shown to be reliable and consistent under all conditions tested and were used to model the rate of loss of transferred particles over a 7-day timescale. The protocol was additionally extended to include a test of camera settings. The protocol was found to be useable and robust in this preliminary trial paving the way for it to be deployed more widely

    Body mass index trajectories in early childhood in relation to cardiometabolic risk profile and body composition at 5 years of age

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    BACKGROUND: Both impaired and accelerated postnatal growth have been associated with adult risks of obesity and cardiometabolic diseases, like type 2 diabetes and cardiovascular disease. However, the timing of the onset of cardiometabolic changes and the specific growth trajectories linking early growth with later disease risks are not well understood. OBJECTIVES: The aim of this study was to identify distinct trajectories of BMI growth from 0 to 5 y and examine their associations with body composition and markers of cardiometabolic risk at age 5 y. METHODS: In a prospective birth cohort study of 453 healthy and term Ethiopian children with BMIs assessed a median of 9 times during follow-up, we identified subgroups of distinct BMI trajectories in early childhood using latent class trajectory modeling. Associations of the identified growth trajectories with cardiometabolic markers and body composition at 5 y were analyzed using multiple linear regression analyses in 4 adjustment models for each outcome. RESULTS: We identified 4 heterogeneous BMI growth trajectories: stable low BMI (19.2%), normal BMI (48.8%), rapid catch-up to high BMI (17.9%), and slow catch-up to high BMI (14.1%). Compared with the normal BMI trajectory, children in the rapid catch-up to high BMI trajectory had higher triglycerides (TGs) (range of ÎČ-coefficients in Models 1-4: 19-21%), C-peptides (23-25%), fat masses (0.48-0.60 kg), and fat-free masses (0.50-0.77 kg) across the 4 adjustment models. Children in the stable low BMI trajectory had lower LDL cholesterol concentrations (0.14-0.17 mmol/L), HDL cholesterol concentrations (0.05-0.09 mmol/L), fat masses (0.60-0.64 kg), and fat-free masses (0.35-0.49 kg), but higher TGs (11-13%). CONCLUSIONS: The development of obesity and cardiometabolic risks may be established already in early childhood; thus, our data provide a further basis for timely interventions targeted at young children from low-income countries with unfavorable growth patterns. The birth cohort was registered at ISRCTN as ISRCTN46718296

    Latent ion tracks in amorphous silicon

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    We present experimental evidence for the formation of ion tracks in amorphous Si induced by swift heavy-ion irradiation. An underlying core-shell structure consistent with remnants of a high-density liquid structure was revealed by small-angle x-ray scattering and molecular dynamics simulations. Ion track dimensions differ for as-implanted and relaxed Si as attributed to differentmicrostructures andmelting temperatures. The identification and characterization of ion tracks in amorphous Si yields new insight into mechanisms of damage formation due to swift heavy-ion irradiation in amorphous semiconductors

    Nanoscale density variations induced by high energy heavy ions in amorphous silicon nitride and silicon dioxide

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    The cylindrical nanoscale density variations resulting from the interaction of 185 MeV and 2.2 GeV Au ions with 1.0 mu m thick amorphous SiNx:H and SiOx:H layers are determined using small angle x-ray scattering measurements. The resulting density profiles resembles an under-dense core surrounded by an over-dense shell with a smooth transition between the two regions, consistent with molecular-dynamics simulations. For amorphous SiNx:H, the density variations show a radius of 4.2 nm with a relative density change three times larger than the value determined for amorphous SiOx:H, with a radius of 5.5 nm. Complementary infrared spectroscopy measurements exhibit a damage cross-section comparable to the core dimensions. The morphology of the density variations results from freezing in the local viscous flow arising from the non-uniform temperature profile in the radial direction of the ion path. The concomitant drop in viscosity mediated by the thermal conductivity appears to be the main driving force rather than the presence of a density anomaly.Peer reviewe
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