A new variational method for finding Einstein metrics on compact Kähler manifolds, I

AbstractLet X be a compact Kähler manifold of complex dimension m. One knows that the determination of Einstein-Kähler metrics on X can be reduced to the solution of complex Monge-Ampère equations, depending on the sign of the first Chern class of X. Here, one studies a unified variational principle in the Sobolev space W2,m(X), whose Euler-Lagrange equations are the p.d.e. in question. The resulting variational problem results in a limit case for the associated Sobolev inequalities

Resource Efficiency in Practice – Closing Mineral Cycles : Final report

Nutrients such as nitrogen (N), phosphorus (P) and potassium (K) are essential elements for living organisms, including plants, animals and bacteria. They are used as fertilisers in agriculture to guarantee high yields and quality products. However, the increasing demand not only in food production, but also in feed, fibre and fuel, has resulted in an increasing use of N, P and K. The depletion of non-renewable resources (such as mined phosphates rock) jeopardises the viability of the current agricultural production systems in the long term. In addition, while progress has been made towards sustainable agricultural practices, a number of inefficiencies are observed in nutrient use which can lead to the degradation of land, soil and water resources. Ultimately, this can impede well-being and economic growth from farm level to EU level. In this context, the first objective of the project \u201cResource efficiency in practice \u2013 Closing mineral cycles\u201d was to identify the most promising measures at regional and farm levels, in particular in nutrient saturated areas, to improve the use of nutrients and to reduce their negative impacts. The second objective was to communicate the information gathered to farmers, farmers\u2019 associations, and regional decision-makers in an educational style to empower them to take action at their level. Communication channels included leaflets, a dedicated website (http://mineral-cycles.eu) and four regional conferences, as well as a final conference in Brussels

Resource efficiency in practice : closing mineral cycles : final report

Nutrients such as nitrogen (N), phosphorus (P) and potassium (K) are essential elements for living organisms, including plants, animals and bacteria. They are used as fertilisers in agriculture to guarantee high yields and quality products. However, the increasing demand not only in food production, but also in feed, fibre and fuel, has resulted in an increasing use of N, P and K. The depletion of non-renewable resources (such as mined phosphates rock) jeopardises the viability of the current agricultural production systems in the long term. In addition, while progress has been made towards sustainable agricultural practices, a number of inefficiencies are observed in nutrient use which can lead to the degradation of land, soil and water resources. Ultimately, this can impede well-being and economic growth from farm level to EU level. In this context, the first objective of the project \u201cResource efficiency in practice \u2013 Closing mineral cycles\u201d was to identify the most promising measures at regional and farm levels, in particular in nutrient saturated areas, to improve the use of nutrients and to reduce their negative impacts. The second objective was to communicate the information gathered to farmers, farmers\u2019 associations, and regional decision-makers in an educational style to empower them to take action at their level. Communication channels included leaflets, a dedicated website (http://mineral-cycles.eu) and four regional conferences, as well as a final conference in Brussels

Sex, estradiol, and spatial memory in a food-caching corvid

Estrogens significantly impact spatial memory function in mammalian species. Songbirds express the estrogen synthetic enzyme aromatase at relatively high levels in the hippocampus and there is evidence from zebra finches that estrogens facilitate performance on spatial learning and/or memory tasks. It is unknown, however, whether estrogens influence hippocampal function in songbirds that naturally exhibit memory-intensive behaviors, such as cache recovery observed in many corvid species. To address this question, we examined the impact of estradiol on spatial memory in non-breeding Western scrub-jays, a species that routinely participates in food caching and retrieval in nature and in captivity. We also asked if there were sex differences in performance or responses to estradiol. Utilizing a combination of an aromatase inhibitor, fadrozole, with estradiol implants, we found that while overall cache recovery rates were unaffected by estradiol, several other indices of spatial memory, including searching efficiency and efficiency to retrieve the first item, were impaired in the presence of estradiol. In addition, males and females differed in some performance measures, although these differences appeared to be a consequence of the nature of the task as neither sex consistently out-performed the other. Overall, our data suggest that a sustained estradiol elevation in a food-caching bird impairs some, but not all, aspects of spatial memory on an innate behavioral task, at times in a sex-specific manner