173 research outputs found

    Growth of collisional orogens from small and cold to large and hot - inferences from geodynamic models

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    It is well documented that the interplay between crustal thickening and surface processes determines growth of continent‐continent collision orogens from small and cold to large and hot. Additionally, studies have demonstrated that the structural style of a mountain belt is strongly influenced by inherited (extensional) structures, the pattern of erosion and deposition, as well as the distribution of shallow detachment horizons. However, the factors controlling distribution of shortening and variable structural style as a function of convergence and surface process efficiency remain less explored. We use a 2D upper‐mantle scale plane‐strain thermo‐mechanical model (FANTOM) coupled to a planform, mass conserving surface‐process model (Fastscape), to investigate the long‐term evolution of mountain belts and the influence of lithospheric pull, extensional inheritance, surface processes efficiency, and decoupling between thin‐and thick‐skinned tectonics. We establish an evolutionary shortening distribution for orogenic growth from a mono‐vergent wedge to an orogenic plateau, and find that internal crustal loading is the main factor controlling the large scale evolution, while lithospheric pull modulates the plate driving force for orogenesis. Limited foreland‐basin filling and minor exhumation of the orogen core are characteristic for low surface‐process efficiency, while thick foreland‐basin fill, and profound exhumation of the orogen core are characteristic for high surface‐process efficiency. Utilizing a force balance analysis, we show how inherited structures, surface processes, and decoupling between thin‐and thick‐skinned deformation influence structural style during orogenic growth. Finally, we present a comparison of our generic modeling results with natural systems, with a particular focus on the Pyrenees, Alps, and Himalaya‐Tibet

    Effect of drug utilization reviews on the quality of in-hospital prescribing: a quasi-experimental study

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    BACKGROUND: Drug utilization review (DUR) programs are being conducted in Canadian hospitals with the aim of improving the appropriateness of prescriptions. However, there is little evidence of their effectiveness. The objective of this study was to assess the impact of both a retrospective and a concurrent DUR programs on the quality of in-hospital prescribing. METHODS: We conducted an interrupted time series quasi-experimental study. Using explicit criteria for quality of prescribing, the natural history of cisapride prescription was established retrospectively in three university-affiliated hospitals. A retrospective DUR was implemented in one of the hospitals, a concurrent DUR in another, whereas the third hospital served as a control. An archivist abstracted records of all patients who were prescribed cisapride during the observation period. The effect of DURs relative to the control hospital was determined by comparing estimated regression coefficients from the time series models and by testing the statistical significance using a 2-tailed Student's t test. RESULTS: The concurrent DUR program significantly improved the appropriateness of prescriptions for the indication for use whereas the retrospective DUR brought about no significant effect on the quality of prescribing. CONCLUSION: Results suggest a retrospective DUR approach may not be sufficient to improve the quality of prescribing. However, a concurrent DUR strategy, with direct feedback to prescribers seems effective and should be tested in other settings with other drugs

    The use of insulin declines as patients live farther from their source of care: results of a survey of adults with type 2 diabetes

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    BACKGROUND: Although most diabetic patients do not achieve good physiologic control, patients who live closer to their source of primary care tend to have better glycemic control than those who live farther away. We sought to assess the role of travel burden as a barrier to the use of insulin in adults with diabetes METHODS: 781 adults receiving primary care for type 2 diabetes were recruited from the Vermont Diabetes Information System. They completed postal surveys and were interviewed at home. Travel burden was estimated as the shortest possible driving distance from the patient's home to the site of primary care. Medication use, age, sex, race, marital status, education, health insurance, duration of diabetes, and frequency of care were self-reported. Body mass index was measured by a trained field interviewer. Glycemic control was measured by the glycosolated hemoglobin A1C assay. RESULTS: Driving distance was significantly associated with insulin use, controlling for the covariates and potential confounders. The odds ratio for using insulin associated with each kilometer of driving distance was 0.97 (95% confidence interval 0.95, 0.99; P = 0.01). The odds ratio for using insulin for those living within 10 km (compared to those with greater driving distances) was 2.29 (1.35, 3.88; P = 0.02). DISCUSSION: Adults with type 2 diabetes who live farther from their source of primary care are significantly less likely to use insulin. This association is not due to confounding by age, sex, race, education, income, health insurance, body mass index, duration of diabetes, use of oral agents, glycemic control, or frequency of care, and may be responsible for the poorer physiologic control noted among patients with greater travel burdens

    Poorly controlled type 2 diabetes is accompanied by significant morphological and ultrastructural changes in both erythrocytes and in thrombin-generated fibrin: implications for diagnostics

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    We have noted in previous work, in a variety of inflammatory diseases, where iron dysregulation occurs, a strong tendency for erythrocytes to lose their normal discoid shape and to adopt a skewed morphology (as judged by their axial ratios in the light microscope and by their ultrastructure in the SEM). Similarly, the polymerization of fibrinogen, as induced in vitro by added thrombin, leads not to the common ‘spaghetti-like’ structures but to dense matted deposits. Type 2 diabetes is a known inflammatory disease. In the present work, we found that the axial ratio of the erythrocytes of poorly controlled (as suggested by increased HbA1c levels) type 2 diabetics was significantly increased, and that their fibrin morphologies were again highly aberrant. As judged by scanning electron microscopy and in the atomic force microscope, these could be reversed, to some degree, by the addition of the iron chelators deferoxamine (DFO) or deferasirox (DFX). As well as their demonstrated diagnostic significance, these morphological indicators may have prognostic value.Biotechnology and Biological Sciences Research Council (grant BB/L025752/1) as well as the National Research Foundation (NRF) of South Africa.http://www.cardiab.com/hb201

    Extremely short duration interval exercise improves 24-h glycaemia in men with type 2 diabetes

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    PurposeReduced-exertion high-intensity interval training (REHIT) is a genuinely time-efficient exercise intervention that improves aerobic capacity and blood pressure in men with type 2 diabetes. However, the acute effects of REHIT on 24-h glycaemia have not been examined.Methods11 men with type 2 diabetes (mean ± SD: age, 52 ± 6 years; BMI, 29.7 ± 3.1 kg/m2; HbA1c, 7.0 ± 0.8%) participated in a randomised, four-trial crossover study, with continual interstitial glucose measurements captured during a 24-h dietary-standardised period following either (1) no exercise (CON); (2) 30 min of continuous exercise (MICT); (3) 10 × 1 min at ~ 90 HRmax (HIIT; time commitment, ~ 25 min); and (4) 2 × 20 s ‘all-out’ sprints (REHIT; time commitment, 10 min).ResultsCompared to CON, mean 24-h glucose was lower following REHIT (mean ± 95%CI: − 0.58 ± 0.41 mmol/L, p = 0.008, d = 0.55) and tended to be lower with MICT (− 0.37 ± 0.41 mmol/L, p = 0.08, d = 0.35), but was not significantly altered following HIIT (− 0.37 ± 0.59 mmol/L, p = 0.31, d = 0.35). This seemed to be largely driven by a lower glycaemic response (area under the curve) to dinner following both REHIT and MICT (− 11%, p  0.9 for both) but not HIIT (− 4%, p = 0.22, d = 0.38). Time in hyperglycaemia appeared to be reduced with all three exercise conditions compared with CON (REHIT: − 112 ± 63 min, p = 0.002, d = 0.50; MICT: -115 ± 127 min, p = 0.08, d = 0.50; HIIT − 125 ± 122 min, p = 0.04, d = 0.54), whilst indices of glycaemic variability were not significantly altered.ConclusionREHIT may offer a genuinely time-efficient exercise option for improving 24-h glycaemia in men with type 2 diabetes and warrants further study
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