884 resultados para Lass, Roger: Historical linguistics and language change


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Livestock farming is one of the most important sectors in agriculture both economically and socially. In the developing world, livestock is crucial to generating livelihoods and food security for some one billion of the world's poorest people. The demand for livestock products is growing as diets change and the world population increases, mainly in the developing world. Climate change only adds to the challenge facing the world's most disadvantaged people. It impacts on livestock production systems and in turn livestock farming impacts on climate change. This paper reviews the complex interaction between livestock production and climate change and proposes strategies that could be used to help sustain livestock as a key feature of rural livelihoods in the developing world.

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A significant challenge in the prediction of climate change impacts on ecosystems and biodiversity is quantifying the sources of uncertainty that emerge within and between different models. Statistical species niche models have grown in popularity, yet no single best technique has been identified reflecting differing performance in different situations. Our aim was to quantify uncertainties associated with the application of 2 complimentary modelling techniques. Generalised linear mixed models (GLMM) and generalised additive mixed models (GAMM) were used to model the realised niche of ombrotrophic Sphagnum species in British peatlands. These models were then used to predict changes in Sphagnum cover between 2020 and 2050 based on projections of climate change and atmospheric deposition of nitrogen and sulphur. Over 90% of the variation in the GLMM predictions was due to niche model parameter uncertainty, dropping to 14% for the GAMM. After having covaried out other factors, average variation in predicted values of Sphagnum cover across UK peatlands was the next largest source of variation (8% for the GLMM and 86% for the GAMM). The better performance of the GAMM needs to be weighed against its tendency to overfit the training data. While our niche models are only a first approximation, we used them to undertake a preliminary evaluation of the relative importance of climate change and nitrogen and sulphur deposition and the geographic locations of the largest expected changes in Sphagnum cover. Predicted changes in cover were all small (generally <1% in an average 4 m2 unit area) but also highly uncertain. Peatlands expected to be most affected by climate change in combination with atmospheric pollution were Dartmoor, Brecon Beacons and the western Lake District.

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Three potential explanations of past reforms of the Common Agricultural Policy (CAP) can be identified in the literature: a budget constraint, pressure from General Agreement on Tariffs and Trade/World Trade Organization (GATT/WTO) negotiations or commitments and a paradigm shift emphasising agriculture’s provision of public goods. This discussion on the driving forces of CAP reform links to broader theoretical questions on the role of budgetary politics, globalisation of public policy and paradigm shift in explaining policy change. In this article, the Health Check reforms of 2007/2008 are assessed. They were probably more ambitious than first supposed, although it was a watered-down package agreed by ministers in November 2008. We conclude that the Health Check was not primarily driven by budget concerns or by the supposed switch from the state-assisted to the multifunctional policy paradigm. The European Commission’s wish to adopt an offensive negotiating stance in the closing phases of the Doha Round was a more likely explanatory factor. The shape and purpose of the CAP post-2013 is contested with divergent views among the Member States.

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