823 resultados para Middle stratum


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Ar-40/Ar-39 total gas and plateau dates from muscovite and biotite in the southern Black Hills, South Dakota, provide evidence for a period of Middle Proterozoic slow cooling. Early Proterozoic (1600-1650 Ma) mica dates were obtained from metasedimentary rocks located in a synformal structure between the Harney Peak and Bear Mountain domes and also south of Bear Mountain. Metamorphic rocks from the dome areas and undeformed samples of the similar to 1710 Ma Harney Peak Granite (HPG) yield Middle Proterozoic mica dates (similar to 1270-1500 Ma). Two samples collected between the synform and Bear Mountain dome yield intermediate total gas mica dates of similar to 1550 Ma. We suggest two end-member interpretations to explain the map pattern of cooling ages: (1) subhorizontal slow cooling of an area which exhibits variation in mica Ar retention intervals or (2) mild folding of a Middle Proterozoic (similar to 1500 Ma) similar to 300 degrees C isotherm. According to the second interpretation, the preservation of older dates between the domes may reflect reactivation of a preexisting synformal structure (and downwarping of relatively cold rocks) during a period of approximately east-west contraction and slow uplift during the Middle Proterozoic. The mica data, together with hornblende data from the Black Hills published elsewhere, indicate that the ambient country-rock temperature at the 3-4 kbar depth of emplacement of the HPG was between 350 degrees C and 500 degrees C, suggesting that the average upper crustal geothermal gradient was 25 degrees-40 degrees C/km prior to intrusion. The thermochronologic data suggest HPG emplacement was followed by a similar to 200 m.y. period of stability and tectonic quiescence with little uplift. We propose that crust thickened during the Early Proterozoic was uplifted and erosionally(?) thinned prior to similar to 1710 Ma and that the HPG magma was emplaced into isostatically stable crust of relatively normal thickness. We speculate that uplift and crustal thinning prior to HPG intrusion was the result of differential thinning of the subcrustal lithosphere beneath the Black Hills. If so, this process would have also caused an increase in mantle heat flux across the Moho and triggered vapor-absent melting of biotite to produce the HPG magma. This scenario for posttectonic granite generation is supported, in part, by the fact that in the whole of the Black Hills, the HPG is spatially associated with the deepest exposed Early Proterozoic country rock.

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Abstract. In this paper, we compare the diurnal variations in middle-atmospheric water vapor as measured by two ground-based microwave radiometers in the Alpine region near Bern, Switzerland. The observational data set is also compared to data from the chemistry–climate model WACCM. Due to the small diurnal variations of usually less than 1%, averages over extended time periods are required. Therefore, two time periods of five months each, December to April and June to October, were taken for the comparison. The diurnal variations from the observational data agree well with each other in amplitude and phase. The linear correlation coefficients range from 0.8 in the upper stratosphere to 0.5 in the upper mesosphere. The observed diurnal variability is significant at all pressure levels within the sensitivity of the instruments. Comparing our observations with WACCM, we find that the agreement of the phase of the diurnal cycle between observations and model is better from December to April than from June to October. The amplitudes of the diurnal variations for both time periods increase with altitude in WACCM, but remain approximately constant at 0.05 ppm in the observations. The WACCM data are used to separate the processes that lead to diurnal variations in middle-atmospheric water vapor above Bern. The dominating processes were found to be meridional advection below 0.1 hPa, vertical advection between 0.1 and 0.02 hPa and (photo-)chemistry above 0.02 hPa. The contribution of zonal advection is small. The highest diurnal variations in water vapor as seen in the WACCM data are found in the mesopause region during the time period from June to October with diurnal amplitudes of 0.2 ppm (approximately 5% in relative units).

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Marital breakup is among the most incisive stressors in adult life. While the negative effects of divorce on well-being are well documented in research literature, the large interindividual differences in psychological adaptation to marital dissolution are still not well understood. One major controversially discussed question is, whether marital dissolution represents a temporary crisis or rather a chronic strain. But also with regard of the role of gender results are mixed. The aim of the present study is to investigate the psychological adaptation (depression, perceived stress and life satisfaction) to marital breakup in a sample of 980 middle-aged persons (M = 51.8 years) who were partnered on average 19.4 years. We compared four time groups: one with a separation within the last 12 months (84 women, 36 men), another within the last 13-24 months (75 women, 19 men), a third within 25-60 months (121 women, 49 men), and one with a separation more than 60 months ago (189 women, 144 men). A group of 348 age-matched married people served as control group (189 women, 159 men). Findings from ANOVA with the outcome depression as well as with the outcome perceived stress yielded a significant main effect for both factors (gender and time). The group who had experienced a separation within the last 12 months differed significantly from all other groups (higher depression score and higher perceived stress). No significant main effect for the factor time was found for the outcome life satisfaction. Regarding gender differences, females from all time groups displayed higher depression scores and higher perceived stress but lower life satisfaction than males. These results give important insights into the process of adaptation to marital breakup, which can be used for counselling.

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by Louis Finkelstein. With a foreword by Alexander Marx

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BACKGROUND AND PURPOSE The use of thrombolysis in patients with minor neurological deficits and large vessel occlusion is controversial. METHODS We compared the outcome of patients with low National Institutes of Health Stroke Scale (NIHSS) scores and large vessel occlusions between thrombolysed and non-thrombolysed patients. RESULTS 88 (1.7%) of 5312 consecutive patients with acute (within 24 h) ischaemic stroke had occlusions of the internal carotid or the main stem of the middle cerebral artery and baseline NIHSS scores ≤5.47 (53.4%) were treated without thrombolysis, and 41 (46.6%) received intravenous thrombolysis, endovascular therapy or both. Successful recanalisation on MR or CT angiography at 24 h was more often observed in thrombolysed than in non-thrombolysed patients (78.9% versus 10.5%; p<0.001). Neurological deterioration (increase of NIHSS score ≥1 compared to baseline) was observed in 22.7% of non-thrombolysed versus 10.3% of thrombolysed after 24 h (p=0.002), in 33.3% versus 12.5% at hospital discharge (p=0.015) and in 41.4% versus 15% at 3 months (p<0.001). Symptomatic intracerebral haemorrhage occurred in two (asymptomatic in five) thrombolysed and in none (asymptomatic in three) non-thrombolysed. Thrombolysis was an independent predictor of favourable outcome (p=0.030) but not survival (p=0.606) at 3 months. CONCLUSIONS Non-thrombolysed patients with mild deficits and large vessel occlusion deteriorated significantly more often within 3 months than thrombolysed patients. Symptomatic intracerebral haemorrhages occurred in less than 5% of patients in both groups. These data suggest that thrombolysis is safe and effective in these patients. Therefore, randomised trials in patients with large vessel occlusions and mild or rapidly improving symptoms are needed.

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Two factors that have been suggested as key in explaining individual differences in fluid intelligence are working memory and sensory discrimination ability. A latent variable approach was used to explore the relative contributions of these two variables to individual differences in fluid intelligence in middle to late childhood. A sample of 263 children aged 7–12 years was examined. Correlational analyses showed that general discrimination ability (GDA)and working memory (WM) were related to each other and to fluid intelligence. Structural equation modeling showed that within both younger and older age groups and the sample as a whole, the relation between GDA and fluid intelligence could be accounted for by WM. While WM was able to predict variance in fluid intelligence above and beyond GDA, GDA was not able to explain significant amounts of variance in fluid intelligence, either in the whole sample or within the younger or older age group. We concluded that compared to GDA, WM should be considered the better predictor of individual differences in fluid intelligence in childhood. WM and fluid intelligence, while not being separable in middle childhood, develop at different rates, becoming more separable with age.

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Images of the medieval past have long been fertile soil for the identity politics of subsequent periods. Rather than “authentically” reproducing the Middle Ages, medievalism therefore usually tells us more about the concerns and ideological climate of its own time and place of origin. To dramatise the nascent nation, Shakespeare resorts to medievalism in his history plays. Centuries later, the BBC-produced television mini-serial The Hollow Crown – adapting Shakespeare’s second histories tetralogy – revamps this negotiation of national identity for the “Cultural Olympiad” in the run-up to the 2012 London Olympics. In this context of celebratory introspection, The Hollow Crown weaves a genealogical narrative consisting of the increasingly “glorious” medieval history depicted and “national” Shakespearean heritage in order to valorise 21st-century “Britishness”. Encouraging a reading of the histories as medieval history, the films construct an ostensibly inclusive, liberal-minded national identity grounded in this history. Moreover, medieval kingship is represented in distinctly sentimentalising and humanising terms, fostering emotional identification especially with the no longer ambivalent Hal/Henry V and making him an apt model for present-day British grandeur. However, the fact that the films in return marginalise female, Scottish, Irish and Welsh characters gives rise to doubts as to whether this vision of Shakespeare’s Middle Ages really is, as the producers claimed, “for everybody”.

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Cross-sectional research implies a close relation of vocation interests, goals, and traits, yet little is known about their reciprocal development over time. This longitudinal study examined development of Things/People (T/P) and Data/Ideas (D/I) vocational interests and career goals in relation to Big Five personality traits among 292 Swiss adolescents with a cross-lagged panel design with two measurement points over 1 year from seventh to eighth grade. Interests and goals were significantly related within time and showed significant interactions across time. Traits related significantly and equally to interests and goals within time and predicted their development across time except for T/P goals. Goals and interests possessed incremental validity above traits in affecting each other. Implications include the need to account for dynamic processes in the development of goals and interests and their systematic relation to traits in theory and practice.

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BACKGROUND The CD4 cell count or percent (CD4%) at the start of combination antiretroviral therapy (cART) is an important prognostic factor in children starting therapy and an important indicator of program performance. We describe trends and determinants of CD4 measures at cART initiation in children from low-, middle-, and high-income countries. METHODS We included children aged <16 years from clinics participating in a collaborative study spanning sub-Saharan Africa, Asia, Latin America, and the United States. Missing CD4 values at cART start were estimated through multiple imputation. Severe immunodeficiency was defined according to World Health Organization criteria. Analyses used generalized additive mixed models adjusted for age, country, and calendar year. RESULTS A total of 34,706 children from 9 low-income, 6 lower middle-income, 4 upper middle-income countries, and 1 high-income country (United States) were included; 20,624 children (59%) had severe immunodeficiency. In low-income countries, the estimated prevalence of children starting cART with severe immunodeficiency declined from 76% in 2004 to 63% in 2010. Corresponding figures for lower middle-income countries were from 77% to 66% and for upper middle-income countries from 75% to 58%. In the United States, the percentage decreased from 42% to 19% during the period 1996 to 2006. In low- and middle-income countries, infants and children aged 12-15 years had the highest prevalence of severe immunodeficiency at cART initiation. CONCLUSIONS Despite progress in most low- and middle-income countries, many children continue to start cART with severe immunodeficiency. Early diagnosis and treatment of HIV-infected children to prevent morbidity and mortality associated with immunodeficiency must remain a global public health priority.