1000 resultados para 324.52


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A common time scale for the EPICA ice cores from Dome C (EDC) and Dronning Maud Land (EDML) has been established. Since the EDML core was not drilled on a dome, the development of the EDML1 time scale for the EPICA ice core drilled in Dronning Maud Land was based on the creation of a detailed stratigraphic link between EDML and EDC, which was dated by a simpler 1D ice-flow model. The synchronisation between the two EPICA ice cores was done through the identification of several common volcanic signatures. This paper describes the rigorous method, using the signature of volcanic sulfate, which was employed for the last 52 kyr of the record. We estimated the discrepancies between the modelled EDC and EDML glaciological age scales during the studied period, by evaluating the ratio R of the apparent duration of temporal intervals between pairs of isochrones. On average R ranges between 0.8 and 1.2 corresponding to an uncertainty of up to 20% in the estimate of the time duration in at least one of the two ice cores. Significant deviations of R up to 1.4–1.5 are observed between 18 and 28 kyr before present (BP), where present is defined as 1950. At this stage our approach does not allow us unequivocally to find out which of the models is affected by errors, but assuming that the thinning function at both sites and accumulation history at Dome C (which was drilled on a dome) are correct, this anomaly can be ascribed to a complex spatial accumulation variability (which may be different in the past compared to the present day) upstream of the EDML core.

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OBJECTIVE: Virologic failure of HIV-positive patients is of special concern during pregnancy. We compared virologic failure and the frequency of treatment changes in pregnant and non-pregnant women of the Swiss HIV Cohort Study. METHODS: Using data on 372 pregnancies in 324 women we describe antiretroviral therapy during pregnancy. Pregnant women on HAART at conception (n = 131) were matched to 228 non-pregnant women (interindividual comparison) and to a time period of equal length before and after pregnancy (intraindividual comparison). Women starting HAART during pregnancy (n = 145) were compared with 578 non-pregnant women starting HAART. FINDINGS: The median age at conception was 31 years, 16% (n = 50) were infected through injecting drug use and the median CD4 cell count was 489 cells/microl. In the majority of pregnancies (n = 220, 59%), women had started ART before conception. When ART was started during pregnancy (n = 145, 39%), it was mainly during the second trimester (n = 100, 69%). Two thirds (n = 26) of 35 women starting in the third trimester were diagnosed with HIV during pregnancy. The risk of virologic failure tended to be lower in pregnant than in non-pregnant women [adjusted odds ratio 0.52 (95% confidence interval 0.25-1.09, P = 0.08)], but was similar in the intraindividual comparison (adjusted odds ratio 1.04, 95% confidence interval 0.48-2.28). Women starting HAART during pregnancy changed the treatment less often than non-pregnant women. CONCLUSION: Despite the physiological changes occurring during pregnancy, HIV infected pregnant women are not at higher risk of virologic failure.

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OBJECTIVES: This study examined the course of low-back pain over 52 weeks following current pain at baseline. Initial beliefs about the inevitability of the pain's negative consequences and fear avoidance beliefs were examined as potential risk factors for persistent low-back pain. METHODS: On a weekly basis over a period of one year, 264 participants reported both the intensity and frequency of their low-back pain and the degree to which it impaired their work performance. In a multilevel regression analysis, predictor variables included initial low-back pain intensity, age, gender, body mass index, anxiety/depression, participation in sport, heavy workload, time (1-52 weeks), and scores on the "back beliefs" and "fear-avoidance beliefs" questionnaires. RESULTS: The group mean values for both the intensity and frequency of weekly low-back pain, and the impairment of work performance due to such pain showed a recovery within the first 12 weeks. In a multilevel regression of 9497 weekly measurements, greater weekly low-back pain and impairment were predicted by higher levels of work-related fear avoidance beliefs. A significant interaction between time and the scores on both the work-related fear-avoidance and back beliefs questionnaires indicated faster recovery and pain relief over time in those who reported less fear-avoidance and fewer negative beliefs. CONCLUSIONS: Negative beliefs about the inevitability of adverse consequences of low-back pain and work-related, fear-avoidance beliefs are independent risk factors for poor recovery from low-back pain.

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Vorbesitzer: Moses Simon Sivitz

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Vorbesitzer: Bartholomaeusstift Frankfurt am Main;