1,891 research outputs found
The St. Lawrence polynya and the Bering shelf circulation : new observations and a model comparison
Author Posting. © American Geophysical Union, 2006. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 111 (2006): C09023, doi:10.1029/2005JC003268.Using 14 year-long instrumented moorings deployed south of St. Lawrence Island, along
with oceanographic drifters, we investigate the circulation over the central Bering shelf and the role of polynyas in forming and disseminating saline waters over the shelf. We focus also on evaluating the Gawarkiewicz and Chapman [1995] model of eddy production within coastal polynyas. Principal results include: 1) The northern central shelf near-surface waters exhibit westward flow carrying low-salinity waters from the Alaskan coast in fall and early winter, with
consequences for water mass formation and biological production. 2) Within the St. Lawrence polynya, the freshening effect of winter advection is about half as large as the salting effect of surface brine flux resulting from freezing. 3) Brine production over the Bering shelf occurs primarily offshore, rather than within coastal polynyas, even though ice production per unit area is much larger within the polynyas. 4) We find little evidence for the geostrophic flow adjustment predicted by recent polynya models. 5) In contrast to the theoretical prediction that dense water from the polynya is carried offshore by eddies, we find negligible cross-shelf eddy density fluxes within and surrounding the polynya and very low levels of eddy energy that decreased from fall to winter, even though dense water accumulated within the polynya and large
cross-shore density gradients developed. 6) It is possible that dense polynya water was advected downstream of our array before appreciable eddy fluxes materialized.This work was supported by National Science Foundation grant OCE9730697 to the University
of Alaska and grant OCE9730823 to the University of Washington. S. M. acknowledges the support of the National Science Foundation under OCE9811097 and of NASA under grant NNG04GM69G. The University of Hamburg
contributions were funded by the Bundesminister fĂŒr Bildung und Wissenschaft. Funding for the drifter deployment was made possible by the North Pacific Research Board, grant NPMRI T2130. Manuscript preparation was additionally supported by Office of Naval Research grants N00014-99-1-0345 and N00014-02-1-0305 to the University of Washington
Clinical Characteristics of Patients Classified as Very High Risk and Not Very High Risk Based on the 2018 AHA/ACC Multi-Society Cholesterol Guideline
Background The 2018 AHA/ACC Cholesterol Guideline recommendation to classify ASCVD patients as very high-risk (VHR) vs not-VHR (NVHR) has important implications for ezetimibe and PCSK9 inhibitor eligibility. We aimed to define the clinical characteristics of these two groups within a large multi-state healthcare system in the Western U.S. Methods We performed a retrospective cohort analysis of patients defined as having ASCVD in 2018 using EHR ICD-10 codes. VHR was defined by â„2 major ASCVD events (ACS â€12 months, history of MI \u3e12 months, ischemic stroke, or symptomatic PAD) or 1 major ASCVD event and â„2 high-risk conditions (age â„65, DM, HTN, smoking, HeFH, CKD, CHF, persistently elevated LDL-C, or prior CABG/PCI). Patients not meeting these criteria were classified as NVHR. Results A total of 180,669 ASCVD patients were identified: 104,123 (58%) were VHR and 76,546 (42%) were NVHR. Mean age and gender was 70.1±13.4 years, 54% male and 73.1±11.9 years, 55% male for the NVHR and VHR groups, respectively. Among patients with a history of MI or recent ACS, 99% and 96% were classified as VHR, respectively (Table). Age â„65, HTN and DM were the most prevalent high-risk conditions. Conclusion Criteria used to predict future CV risk largely divide ASCVD patients into groups of similar prevalence. Nearly all ACS/MI patients were VHR. With growing emphasis on individualized risk assessment and intense LDL-C reduction, opportunity exists to further refine risk prediction within these two at-risk groups
Lipoprotein sub-fractions by ion-mobility analysis and its association with subclinical coronary atherosclerosis in high-risk individuals
Aims: There is limited knowledge about the association of lipoprotein particles and markers of coronary atherosclerosis such as coronary artery calcification (CAC) in relatively young high-risk persons. This study examines the association of lipoprotein subfractions and CAC in high cardiometabolic risk individuals. Methods: The study presents analysis from baseline data of a randomized trial targeted at high-risk workers. Employees of Baptist Health South Florida with metabolic syndrome or diabetes were recruited. At baseline, all 182 participants had lipoprotein subfraction analysis using the ion mobility technique and participants above 35 years (N =170) had CAC test done. Principal components (PC) were computed for the combination of lipoprotein subclasses. Multiple bootstrapped regression analyses (BSA) were conducted to assess the relationship between lipoprotein subfractions and CAC. Results: The study population (N=170) was largely female (84%) with a mean age of 58 years. Three PCs accounted for 88% variation in the sample. PC2, with main contributions from VLDL particles in the positive direction and large LDL particles in the negative direction was associated with a 22% increase in CAC odds (P value ïŒ0.05 in 100% of BSA). PC3, with main contributions from HDL lipoprotein particles in the positive direction and small/medium LDL and large IDL particles in the negative direction, was associated with a 9% reduction in CAC odds (PïŒ0.05 in 88% of BSA). PC1, which had approximately even contributions from HDL, LDL, IDL and VLDL lipoprotein subfractions in the positive direction, was not associated with CAC. Conclusion: In a relatively young but high-risk population, a lipoprotein profile predominated by triglyceride-rich lipoproteins was associated with increased risk of CAC, while one predominated by HDL lipoproteins offered modest protection. Lipoprotein sub-fraction analysis may help to further discriminate patients who require more intensive cardiovascular work-up and treatment
Association of Lowering LowâDensity Lipoprotein Cholesterol With Contemporary LipidâLowering Therapies and Risk of Diabetes Mellitus: A Systematic Review and MetaâAnalysis
Background
The relationship between lowering LDL (lowâdensity lipoprotein) cholesterol with contemporary lipidâlowering therapies and incident diabetes mellitus (DM) remains uncertain. Methods and Results
Thirtyâthree randomized controlled trials (21 of statins, 12 of PCSK9 [proprotein convertase subtilisin/kexin type 9] inhibitors, and 0 of ezetimibe) were selected using Medline, Embase, and the Cochrane Central Register of Controlled Trials (inception through November 15, 2018). A total of 163 688 nondiabetic patients were randomly assigned to more intensive (83 123 patients) or less intensive (80 565 patients) lipidâlowering therapy. More intensive lipidâlowering therapy was defined as the more potent pharmacological strategy (PCSK9 inhibitors, higher intensity statins, or statins), whereas less intensive therapy corresponded to active control group or placebo/usual care of the trial. Metaregression and metaâanalyses were conducted using a randomâeffects model. No significant association was noted between 1âmmol/L reduction in LDL cholesterol and incident DM for more intensive lipidâlowering therapy (risk ratio: 0.95; 95% CI, 0.87â1.04; P=0.30; R2=14%) or for statins or PCSK9 inhibitors. More intensive lipidâlowering therapy was associated with a higher risk of incident DM compared with less intensive therapy (risk ratio: 1.07; 95% CI, 1.03â1.11; P\u3c0.001; I2=0%). These results were driven by higher risk of incident DM with statins (risk ratio: 1.10; 95% CI, 1.05â1.15; P\u3c0.001; I2=0%), whereas PCSK9 inhibitors were not associated with incident DM (risk ratio: 1.00; 95% CI, 0.93â1.07; P=0.96; I2=0%; P=0.02 for interaction). Conclusions
Among intensive lipidâlowering therapies, there was no independent association between reduction in LDL cholesterol and incident DM. The risk of incident DM was higher with statins, whereas PCSK9 inhibitors had no association with risk of incident DM
Constraints on Low-Mass WIMP Interactions on 19F from PICASSO
Recent results from the PICASSO dark matter search experiment at SNOLAB are
reported. These results were obtained using a subset of 10 detectors with a
total target mass of 0.72 kg of 19F and an exposure of 114 kgd. The low
backgrounds in PICASSO allow recoil energy thresholds as low as 1.7 keV to be
obtained which results in an increased sensitivity to interactions from Weakly
Interacting Massive Particles (WIMPs) with masses below 10 GeV/c^2. No dark
matter signal was found. Best exclusion limits in the spin dependent sector
were obtained for WIMP masses of 20 GeV/c^2 with a cross section on protons of
sigma_p^SD = 0.032 pb (90% C.L.). In the spin independent sector close to the
low mass region of 7 GeV/c2 favoured by CoGeNT and DAMA/LIBRA, cross sections
larger than sigma_p^SI = 1.41x10^-4 pb (90% C.L.) are excluded.Comment: 23 pages, 7 figures, to be published in Phys. Lett.
Isotretinoin Use and the Risk of Inflammatory Bowel Disease: A CaseâControl Study
Isotretinoin is commonly prescribed for the treatment of severe acne. Though cases of inflammatory bowel disease (IBD) have been reported in isotretinoin users, a causal association remains unproven
Accuracy of 23 Equations for Estimating LDL Cholesterol in a Clinical Laboratory Database of 5,051,467 Patients
Background: Alternatives to the Friedewald low-density lipoprotein cholesterol (LDL-C) equation have been proposed. Objective: To compare the accuracy of available LDL-C equations with ultracentrifugation measurement. Methods: We used the second harvest of the Very Large Database of Lipids (VLDbL), which is a population-representative convenience sample of adult and pediatric patients (N = 5,051,467) with clinical lipid measurements obtained via the vertical auto profile (VAP) ultracentrifugation method between October 1, 2015 and June 30, 2019. We performed a systematic literature review to identify available LDL-C equations and compared their accuracy according to guideline-based classification. We also compared the equations by their median error versus ultracentrifugation. We evaluated LDL-C equations overall and stratified by age, sex, fasting status, and triglyceride levels, as well as in patients with atherosclerotic cardiovascular disease, hypertension, diabetes, kidney disease, inflammation, and thyroid dysfunction. Results: Analyzing 23 identified LDL-C equations in 5,051,467 patients (mean±SD age, 56±16 years; 53.3% women), the Martin/Hopkins equation most accurately classified LDL-C to the correct category (89.6%), followed by the Sampson (86.3%), Chen (84.4%), Puavilai (84.1%), Delong (83.3%), and Friedewald (83.2%) equations. The other 17 equations were less accurate than Friedewald, with accuracy as low as 35.1%. The median error of equations ranged from â10.8 to 18.7 mg/dL, and was best optimized using the Martin/Hopkins equation (0.3, IQRâ1.6 to 2.4 mg/dL). The Martin/Hopkins equation had the highest accuracy after stratifying by age, sex, fasting status, triglyceride levels, and clinical subgroups. In addition, one in five patients who had Friedewald LDL-C 70 mg/dL by the Martin/Hopkins equation. Conclusions: Most proposed alternatives to the Friedewald equation worsen LDL-C accuracy, and their use could introduce unintended disparities in clinical care. The Martin/Hopkins equation demonstrated the highest LDL-C accuracy overall and across subgroups
Mercury Biogeochemical Cycling: A Synthesis of Recent Scientific Advances
The focus of this paper is to briefly discuss the major advances in scientific thinking regarding: a) processes governing the fate and transport of mercury in the environment; b) advances in measurement methods; and c) how these advances in knowledge fit in within the context of the Minamata Convention on Mercury. Details regarding the information summarized here can be found in the papers associated with this Virtual Special Issue of STOTEN
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Access to shops: The views of low-income shoppers
Concern is mounting as the retail stranglehold upon access to food grows. Research on the implications of restructuring retailing and health inequality has failed to involve low-income consumers in this debate. This paper reports on an exercise conducted for the UK Government's, Social Exclusion Unit's Policy Action Team on Access to Shops. The survey provides a useful baseline of the views of low-income groups in England. The choices that people on low income can make were found to be dominated by certain factors such as income and, most importantly, transport. Consumers reported varying levels of satisfaction with retail provision. The findings suggest gaps between what people have, what they want and what the planning process does and does not offer them. Better policy and processes are needed to include and represent the interests of low-income groups
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