342 research outputs found
Particle Size Specific Magnetic Properties Across the NorwegianâGreenland Seas: Insights Into the Influence of Sediment Source and Texture on Bulk Magnetic Records
We make fundamental observations of the particle size variability of magnetic properties from 71 core tops that span the southern Greenland and Norwegian Seas. These data provide the first detailed regional characterization of how bulk magnetic properties vary with sediment texture, sediment source, and sediment transport. Magnetic susceptibility (MS) and hysteresis parameters were measured on the bulk sediment and the five constituent sediment particle size fractions (clay, fine silt, medium silt, coarse silt, and sand). The median MS value of the medium silt size fraction is ~3â5 times higher than that of the sand and clay size fractions and results in a strong sensitivity of bulk MS to sediment texture. Hysteresis properties of the clay size fraction are relatively homogeneous and contrast that silt and sand size fractions which show regional differences across the study area. These coarser fractions are more transport limited and using medium silt hysteresis measurements and low temperature MS behavior we establish three endmembers that effectively explain the variability observed across the region. We model the response of bulk magnetic properties to changes in sediment texture and suggest that variations in sediment source are required to explain the bulk magnetic property variability observed in cores across the southern Greenland and Norwegian Seas. These findings imply that sediment source has a greater influence on driving bulk magnetic property variability across this region than has previously been assumed
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Lewy Body Dementia Association\u27s Research Centers of Excellence Program: Inaugural Meeting Proceedings.
The first Lewy Body Dementia Association (LBDA) Research Centers of Excellence (RCOE) Investigator\u27s meeting was held on December 14, 2017, in New Orleans. The program was established to increase patient access to clinical experts on Lewy body dementia (LBD), which includes dementia with Lewy bodies (DLB) and Parkinson\u27s disease dementia (PDD), and to create a clinical trials-ready network. Four working groups (WG) were created to pursue the LBDA RCOE aims: (1) increase access to high-quality clinical care, (2) increase access to support for people living with LBD and their caregivers, (3) increase knowledge of LBD among medical and allied (or other) professionals, and (4) create infrastructure for a clinical trials-ready network as well as resources to advance the study of new therapeutics
Lamotrigine for people with borderline personality disorder: a RCT
Background: No drug treatments are currently licensed for the treatment of borderline personality disorder (BPD). Despite this, people with this condition are frequently prescribed psychotropic medications and often with considerable polypharmacy. Preliminary studies have indicated that mood stabilisers may be of benefit to people with BPD.
Objective: To examine the clinical effectiveness and cost-effectiveness of lamotrigine for people with BPD.
Design: A two-arm, double-blind, placebo-controlled individually randomised trial of lamotrigine versus placebo. Participants were randomised via an independent and remote web-based service using permuted blocks and stratified by study centre, the severity of personality disorder and the extent of hypomanic symptoms.
Setting: Secondary care NHS mental health services in six centres in England.
Participants: Potential participants had to be aged â„ 18 years, meet diagnostic criteria for BPD and provide written informed consent. We excluded people with coexisting psychosis or bipolar affective disorder, those already taking a mood stabiliser, those who spoke insufficient English to complete the baseline assessment and women who were pregnant or contemplating becoming pregnant.
Interventions: Up to 200 mg of lamotrigine per day or an inert placebo. Women taking combined oral contraceptives were prescribed up to 400 mg of trial medication per day.
Main outcome measures: Outcomes were assessed at 12, 24 and 52 weeks after randomisation.
The primary outcome was the total score on the Zanarini Rating Scale for Borderline Personality Disorder (ZAN-BPD) at 52 weeks. The secondary outcomes were depressive symptoms, deliberate self-harm, social functioning, health-related quality of life, resource use and costs, side effects of treatment and adverse events. Higher scores on all measures indicate poorer outcomes.
Results: Between July 2013 and October 2015 we randomised 276 participants, of whom 195 (70.6%) were followed up 52 weeks later. At 52 weeks, 49 (36%) of those participants prescribed lamotrigine and 58 (42%) of those prescribed placebo were taking it. At 52 weeks, the mean total ZAN-BPD score was 11.3 [standard deviation (SD) 6.6] among those participants randomised to lamotrigine and 11.5 (SD 7.7) among those participants randomised to placebo (adjusted mean difference 0.1, 95% CI â1.8 to 2.0; p = 0.91). No statistically significant differences in secondary outcomes were seen at any time. Adjusted costs of direct care for those prescribed lamotrigine were similar to those prescribed placebo.
Limitations: Levels of adherence in this pragmatic trial were low, but greater adherence was not associated with better mental health.
Conclusions: The addition of lamotrigine to the usual care of people with BPD was not found to be clinically effective or provide a cost-effective use of resources.
Future work: Future research into the treatment of BPD should focus on improving the evidence base for the clinical effectiveness and cost-effectiveness of non-pharmacological treatments to help policy-makers make better decisions about investing in specialist treatment services
Restoration of disk height through non-surgical spinal decompression is associated with decreased discogenic low back pain: a retrospective cohort study
<p>Abstract</p> <p>Background</p> <p>Because previous studies have suggested that motorized non-surgical spinal decompression can reduce chronic low back pain (LBP) due to disc degeneration (discogenic low back pain) and disc herniation, it has accordingly been hypothesized that the reduction of pressure on affected discs will facilitate their regeneration. The goal of this study was to determine if changes in LBP, as measured on a verbal rating scale, before and after a 6-week treatment period with non-surgical spinal decompression, correlate with changes in lumbar disc height, as measured on computed tomography (CT) scans.</p> <p>Methods</p> <p>A retrospective cohort study of adults with chronic LBP attributed to disc herniation and/or discogenic LBP who underwent a 6-week treatment protocol of motorized non-surgical spinal decompression via the DRX9000 with CT scans before and after treatment. The main outcomes were changes in pain as measured on a verbal rating scale from 0 to 10 during a flexion-extension range of motion evaluation and changes in disc height as measured on CT scans. Paired t-test or linear regression was used as appropriate with p < 0.05 considered to be statistically significant.</p> <p>Results</p> <p>We identified 30 patients with lumbar disc herniation with an average age of 65 years, body mass index of 29 kg/m<sup>2</sup>, 21 females and 9 males, and an average duration of LBP of 12.5 weeks. During treatment, low back pain decreased from 6.2 (SD 2.2) to 1.6 (2.3, p < 0.001) and disc height increased from 7.5 (1.7) mm to 8.8 (1.7) mm (p < 0.001). Increase in disc height and reduction in pain were significantly correlated (r = 0.36, p = 0.044).</p> <p>Conclusions</p> <p>Non-surgical spinal decompression was associated with a reduction in pain and an increase in disc height. The correlation of these variables suggests that pain reduction may be mediated, at least in part, through a restoration of disc height. A randomized controlled trial is needed to confirm these promising results.</p> <p>Clinical trial registration number</p> <p>NCT00828880</p
Towards nationally curated data archives for clinical radiology image analysis at scale: Learnings from national data collection in response to a pandemic
The prevalence of the coronavirus SARS-CoV-2 disease has resulted in the unprecedented collection of health data to support research. Historically, coordinating the collation of such datasets on a national scale has been challenging to execute for several reasons, including issues with data privacy, the lack of data reporting standards, interoperable technologies, and distribution methods. The coronavirus SARS-CoV-2 disease pandemic has highlighted the importance of collaboration between government bodies, healthcare institutions, academic researchers and commercial companies in overcoming these issues during times of urgency. The National COVID-19 Chest Imaging Database, led by NHSX, British Society of Thoracic Imaging, Royal Surrey NHS Foundation Trust and Faculty, is an example of such a national initiative. Here, we summarise the experiences and challenges of setting up the National COVID-19 Chest Imaging Database, and the implications for future ambitions of national data curation in medical imaging to advance the safe adoption of artificial intelligence in healthcare
Using imaging to combat a pandemic:rationale for developing the UK National COVID-19 Chest Imaging Database
No abstract available
Meta-analysis of genome-wide association studies from the CHARGE consortium identifies common variants associated with carotid intima media thickness and plaque
Carotid intima media thickness (cIMT) and plaque determined by ultrasonography are established measures of subclinical atherosclerosis that each predicts future cardiovascular disease events. We conducted a meta-analysis of genome-wide association data in 31,211 participants of European ancestry from nine large studies in the setting of the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) Consortium. We then sought additional evidence to support our findings among 11,273 individuals using data from seven additional studies. In the combined meta-analysis, we identified three genomic regions associated with common carotid intima media thickness and two different regions associated with the presence of carotid plaque (P < 5 Ă 10 -8). The associated SNPs mapped in or near genes related to cellular signaling, lipid metabolism and blood pressure homeostasis, and two of the regions were associated with coronary artery disease (P < 0.006) in the Coronary Artery Disease Genome-Wide Replication and Meta-Analysis (CARDIoGRAM) consortium. Our findings may provide new insight into pathways leading to subclinical atherosclerosis and subsequent cardiovascular events
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Regionally consistent Western North America paleomagnetic directions from 15 to 35 ka: Assessing chronology and uncertainty with paleosecular variation (PSV) stratigraphy
New Paleomagnetic Secular Variation (PSV) data from Fish Lake, Utah, USA, along with previously published regional records, allow us to build an independently dated Western North America PSV stack (WNAM17) from about 35 to 15 ka that quantifies dating and paleomagnetic uncertainties. In February 2014, we recovered a composite 11-m-long sediment record from Fish Lake, Utah that retrieved glacially influenced and post-glacial sediments. Computed tomography (CT) scans and magnetic susceptibility were used to build a precise depth scale, while radiocarbon dating of terrestrial macrofossils and tephrostratigraphy provide tight age-control. Glacially influenced sediments have well-defined characteristic remanent magnetizations with all maximum angular deviation values < 5 degrees, resolving a record of Late Pleistocene PSV. Comparison to the PSV records at Bear Lake, Utah/Idaho, USA and Bessette Creak, British Columbia, Canada, which also contain terrestrial material radiocarbon age-control points, allow us to develop the WNAM17 PSV stack which considers both dating and magnetic acquisition uncertainties. We utilize a regional PSV chronostratigraphic modeling approach to assign chronology and uncertainty to the PSV signal and to evaluate the fidelity of age-control points at the site level that are difficult to objectively evaluate otherwise. The greatest strength of our age-depth model is that by approaching chronostratigraphy from a regional perspective, assuming a common geomagnetic signal, we can address sources of geologic uncertainty that would be difficult to quantify using only one site. We illustrate the potential stratigraphic opportunities using the WNAM17 PSV template through assessing the timing of paleoenvironmental and paleomagnetic events in Western North America, including the timing of glaciations in the Fish Lake and Bear Lake catchments and the stratigraphic context for the Late Pleistocene geomagnetic excursion recorded at Mono Lake. (C) 2018 Elsevier Ltd. All rights reserved
TESS Hunt for Young and Maturing Exoplanets (THYME) IX: a 27 Myr extended population of Lower-Centaurus Crux with a transiting two-planet system
We report the discovery and characterization of a nearby (~ 85 pc), older (27
+/- 3 Myr), distributed stellar population near Lower-Centaurus-Crux (LCC),
initially identified by searching for stars co-moving with a candidate
transiting planet from TESS (HD 109833; TOI 1097). We determine the association
membership using Gaia kinematics, color-magnitude information, and rotation
periods of candidate members. We measure it's age using isochrones,
gyrochronology, and Li depletion. While the association is near known
populations of LCC, we find that it is older than any previously found LCC
sub-group (10-16 Myr), and distinct in both position and velocity. In addition
to the candidate planets around HD 109833 the association contains four
directly-imaged planetary-mass companions around 3 stars, YSES-1, YSES-2, and
HD 95086, all of which were previously assigned membership in the younger LCC.
Using the Notch pipeline, we identify a second candidate transiting planet
around HD 109833. We use a suite of ground-based follow-up observations to
validate the two transit signals as planetary in nature. HD 109833 b and c join
the small but growing population of <100 Myr transiting planets from TESS. HD
109833 has a rotation period and Li abundance indicative of a young age (< 100
Myr), but a position and velocity on the outskirts of the new population, lower
Li levels than similar members, and a CMD position below model predictions for
27 Myr. So, we cannot reject the possibility that HD 109833 is a young field
star coincidentally nearby the population.Comment: 23 pages, 15 figures, Accepted for publication in A
Holocene break-up and reestablishment of the Petermann Ice Tongue, Northwest Greenland
Over the last decade, two major calving events of the Petermann Ice Tongue in Northwest Greenland have led to speculation on its future stability and contribution to further Greenland Ice Sheet mass loss. However, it has been unclear if these events are anomalous or typical within the context of limited historical observations. We extend the historical record of the floating ice tongue using the stratigraphy of Petermann Fjord sediments to provide a longer-term perspective. Computed tomography (CT) scans, X-Ray Fluorescence (XRF) scans, Ice-Rafted Debris (IRD) counts, and the magnetic properties of specific particle size fractions constrain changes in depositional processes and sediment sources at our core sites, allowing for reconstructions of past behavior of the Petermann Ice Tongue. Radiocarbon dating of foraminifera, 210Pb, and paleomagnetic secular variation (PSV) provide age control and help to address uncertainties in radiocarbon reservoir ages. A floating ice tongue in Petermann Fjord formed in late glacial time as Petermann Glacier retreated from an advanced grounded position. This paleo-ice tongue broke-up during the early Holocene when high northern latitude summer insolation was higher than present. After gradual regrowth of the ice tongue associated with regional cooling, the ice tongue reached its historical extent only within the last millennium. Little or no ice tongue was present for nearly 5000 years during the middle Holocene, when decadal mean regional temperatures are estimated to be 0.8e2.9 °C higher than preindustrial (1750 CE) and seasonal sea-ice in the Lincoln Sea was reduced. This pre-historical behavior shows that recent anthropogenic warming may already be in the range of ice tongue instability and future projected warming increases the risk of ice tongue break-up by the mid- 21st Century
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