63 resultados para recent 300 years


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Forest decline played a pivotal role in motivating Europe's political focus on sustainability around 35 years ago. Silver fir (Abies alba) exhibited a particularly severe dieback in the mid-1970s, but disentangling biotic from abiotic drivers remained challenging because both spatial and temporal data were lacking. Here, we analyze 14 136 samples from living trees and historical timbers, together with 356 pollen records, to evaluate recent fir growth from a continent-wide and Holocene-long perspective. Land use and climate change influenced forest growth over the past millennium, whereas anthropogenic emissions of acidic sulfates and nitrates became important after about 1850. Pollution control since the 1980s, together with a warmer but not drier climate, has facilitated an unprecedented surge in productivity across Central European fir stands. Restricted fir distribution prior to the Mesolithic and again in the Modern Era, separated by a peak in abundance during the Bronze Age, is indicative of the long-term interplay of changing temperatures, shifts in the hydrological cycle, and human impacts that have shaped forest structure and productivity.

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As the understanding and representation of the impacts of volcanic eruptions on climate have improved in the last decades, uncertainties in the stratospheric aerosol forcing from large eruptions are now linked not only to visible optical depth estimates on a global scale but also to details on the size, latitude and altitude distributions of the stratospheric aerosols. Based on our understanding of these uncertainties, we propose a new model-based approach to generating a volcanic forcing for general circulation model (GCM) and chemistry–climate model (CCM) simulations. This new volcanic forcing, covering the 1600–present period, uses an aerosol microphysical model to provide a realistic, physically consistent treatment of the stratospheric sulfate aerosols. Twenty-six eruptions were modeled individually using the latest available ice cores aerosol mass estimates and historical data on the latitude and date of eruptions. The evolution of aerosol spatial and size distribution after the sulfur dioxide discharge are hence characterized for each volcanic eruption. Large variations are seen in hemispheric partitioning and size distributions in relation to location/date of eruptions and injected SO2 masses. Results for recent eruptions show reasonable agreement with observations. By providing these new estimates of spatial distributions of shortwave and long-wave radiative perturbations, this volcanic forcing may help to better constrain the climate model responses to volcanic eruptions in the 1600–present period. The final data set consists of 3-D values (with constant longitude) of spectrally resolved extinction coefficients, single scattering albedos and asymmetry factors calculated for different wavelength bands upon request. Surface area densities for heterogeneous chemistry are also provided.

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OBJECTIVES: To determine whether current influenza vaccination is associated with reduced risk of major vascular events in patients with recent ischemic stroke or TIA of mainly atherothrombotic origin. METHODS: Data were pooled from 2 prospective cohort studies, the OPTIC Registry (n = 3,635) and the AMISTAD Study (n = 618), and from the randomized PERFORM Trial (n = 19,120), all of which included patients with recent ischemic stroke or TIA. Influenza vaccination status was determined in 23,110 patients. The primary outcome was a composite of nonfatal myocardial infarction, nonfatal stroke, or vascular death up to 2 years. Secondary outcomes were myocardial infarction and stroke separately. RESULTS: Influenza vaccination had no association with the primary outcome in the propensity score-matched cohort (hazard ratio 0.97, 95% confidence interval [CI] 0.85-1.11; p = 0.67) or in the propensity score-adjusted cohort (hazard ratio 1.00, 95% CI 0.89-1.12; p = 0.99). Similarly, the risk of stroke and myocardial infarction did not differ between the vaccinated group and the unvaccinated group; in the matched cohort, the hazard ratio was 1.01 (95% CI 0.88-1.17; p = 0.89) for stroke and 0.84 (95% CI 0.59-1.18; p = 0.30) for myocardial infarction. CONCLUSIONS: Influenza vaccination was not associated with reduced outcome events in patients with recent atherothrombotic ischemic stroke after considering all baseline characteristics (including concomitant medications) associated with influenza vaccination.

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The European Territorial Cohesion Policy has been the subject of numerous debates in recent years. Most contributions focus on understanding the term itself and figuring out what is behind it, or arguing for or against a stronger formal competence of the European Union in this field. This article will leave out these aspects and pay attention to (undefined and legally non-binding) conceptual elements of territorial cohesion, focusing on the challenge of linking it within spatial policies and organising the relations. Therefore, the theoretical approach of Cultural Theory and its concept of clumsy solution are applied to overcome the dilemma of typical dichotomies by adding a third and a fourth (but not a fifth) perspective. In doing so, normative contradictions between different rational approaches can be revealed, explained and approached with the concept of ‘clumsy solutions’. This contribution aims at discussing how this theoretical approach helps us explain and frame a coalition between the Territorial Cohesion Policy and spatial policies. This approach contributes to finding the best way of linking and organising policies, although the solution might be clumsy according to the different rationalities involved.

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Groundwater with underground residence times between days and a few years have been investigated over more than 20 years from 487 remote sites located in different aquifer types in the Alpine belt. Analysis of the data reveals that groundwaters evolved in crystalline, evaporite, carbonate, molasse, and flysch aquifers can be clearly distinguished based on their major and trace element composition and degree of mineralisation. A further subdivision can be made even within one aquifer type based on the trace element compositions, which are characteristic for the lithologic environment. Major and trace element concentrations can be quantitatively described by interaction of the groundwater with the aquifer- specific mineralogy along the flow path. Because all investigated sites show minimal anthropogenic influences, the observed concentration ranges represent the natural background concentrations and can thus serve as a “geo-reference” for recent groundwaters from these five aquifer types. This “geo-reference” is particularly useful for the identification of groundwater contamination. It further shows that drinking water standards can be grossly exceeded for critical elements by purely natural processes

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Introduction Research has shown that individuals infer their group-efficacy beliefs from the groups’ abilities to perform in specific tasks. Group abilities also seem to affect team members’ performance motivation adding a psychological advantage to teams already high on task relevant abilities. In a recent study we found the effect of group abilities on individual performance motivation to be partially mediated by the team members’ individual group-efficacy beliefs which is an example of how attributes on a group-level can be affecting individual-level parameters. Objectives The study aimed at testing the possibility to reduce the direct and mediated effects of low group abilities on performance motivation by augmenting the visibility of individual contributions to group performances via the inclusion of a separate ranking on individual performances. Method Forty-seven students (M=22.83 years, SD=2.83, 34% women) of the University of Bern participated in the study. At three collection points (t1-3) subjects were provided information about fictive team members with whom they had to imagine performing a group triathlon. Three values (low, medium, high) of the other team members’ abilities to perform in their parts of the triathlon (swimming and biking) were combined in a 3x3 full factorial design yielding nine groups with different ability profiles. At t1 subjects were asked to rate their confidence that the teams would perform well in the triathlon task, at t2 and t3 subjects were asked how motivated they were to perform at their best in the respective groups. At t3 the presence of an individual performance ranking was mentioned in the cover story. Mixed linear models (SPSS) and structural equation models for complex survey data (Mplus) were specified to estimate the effects of the individual performance rankings on the relationship between group-efficacy beliefs and performance motivation. Results A significant interaction effect for individual group-efficacy beliefs and the triathlon condition on performance motivation was found; the effect of group-efficacy beliefs on performance motivation being smaller with individual performance rankings available. The partial mediation of group attributes on performance motivation by group-efficacy beliefs disappeared with the announcement of individual performance rankings. Conclusion In teams low in task relevant abilities the disadvantageous effect of group-efficacy beliefs on performance motivation might be reduced by providing means of evaluating individual performances apart from a group’s overall performance. While it is believed that a common group goal is a core criterion for a well performing sport group future studies should also aim at the possible benefit of individualized goal setting in groups.

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The enduring electoral success of populist parties across Europe and the increasing opportunities they have gained to access government in recent years bring once more into relief the question of whether populism and democracy are fully compatible. In this article we show how, despite playing different roles in government within very different political systems, and despite the numerous constraints placed upon them (for instance, EU membership, international law and domestic checks and balances), populist parties consistently pursued policies that clashed with fundamental tenets of liberal democracy. In particular, the idea that the power of the majority must be limited and restrained, the sanctity of individual rights and the principle of the division of powers have all come under threat in contemporary Europe. This has contributed to the continuing erosion of the liberal consensus, which has provided one of the fundamental foundations of the European project from its start.

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Introduction Research has shown that individuals infer their group-efficacy beliefs from the groups’ abilities to perform in specific tasks. Group abilities also seem to affect team members’ performance motivation adding a psychological advantage to teams already high on task relevant abilities. In a recent study we found the effect of group abilities on individual performance motivation to be partially mediated by the team members’ individual group-efficacy beliefs which is an example of how attributes on a group-level can be affecting individual-level parameters. Objectives The study aimed at testing the possibility to reduce the direct and mediated effects of low group abilities on performance motivation by augmenting the visibility of individual contributions to group performances via the inclusion of a separate ranking on individual performances. Method Forty-seven students (M=22.83 years, SD=2.83, 34% women) of the University of Bern participated in the study. At three collection points (t1-3) subjects were provided information about fictive team members with whom they had to imagine performing a group triathlon. Three values (low, medium, high) of the other team members’ abilities to perform in their parts of the triathlon (swimming and biking) were combined in a 3x3 full factorial design yielding nine groups with different ability profiles. At t1 subjects were asked to rate their confidence that the teams would perform well in the triathlon task, at t2 and t3 subjects were asked how motivated they were to perform at their best in the respective groups. At t3 the presence of an individual performance ranking was mentioned in the cover story. Mixed linear models (SPSS) and structural equation models for complex survey data (Mplus) were specified to estimate the effects of the individual performance rankings on the relationship between group-efficacy beliefs and performance motivation. Results A significant interaction effect for individual group-efficacy beliefs and the triathlon condition on performance motivation was found; the effect of group-efficacy beliefs on performance motivation being smaller with individual performance rankings available. The partial mediation of group attributes on performance motivation by group-efficacy beliefs disappeared with the announcement of individual performance rankings. Conclusion In teams low in task relevant abilities the disadvantageous effect of group-efficacy beliefs on performance motivation might be reduced by providing means of evaluating individual performances apart from a group’s overall performance. While it is believed that a common group goal is a core criterion for a well performing sport group future studies should also aim at the possible benefit of individualized goal setting in groups.

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PURPOSE OF REVIEW There is controversy regarding the optimal choice of prosthetic valves in patients less than 65 years of age requiring mitral valve replacement (MVR). Recently, trends for valve replacement are moving towards biological prosthesis also in younger patients, which is justified by the fact that a later valve-in-valve procedure is feasible in the case of degeneration of the tissue valve. This strategy is increasingly recommended in aortic valve surgery but is questionable for MVR. The purpose of this review is to evaluate current guidelines and analyse evidence for biological MVR in patients under 65 years. RECENT FINDINGS There are differences between guidelines of the American Heart Association and those of the European Society of Cardiology concerning the choice of prostheses in patients undergoing MVR. Although the European Society of Cardiology recommends a mechanical mitral valve in patients under 65 years of age, the American Heart Association does not provide detailed advice for these patients. Mitral valve replacement with biological valves in patients under 65 years is associated with higher rates of reoperation due to structural valve deterioration. In addition, several studies showed a decreased survival after biological MVR. SUMMARY Evidence for biological MVR in patients less than 65 years without comorbidities or contraindication for oral anticoagulation does not exist. Recommendations for patients less than 65 years of age should not be blurred by current 'en-vogue' methods for promising but not yet proven valve-in-valve strategies.