Explore the vast range of titles available.

Question: How do species traits respond to environmental conditions and what is their effect on ecosystem properties? Location: Salt marshes, Northwest Germany. Methods: On 113 plots along the German mainland coast and on one island, we measured environmental parameters (soil nutrient content, inundation frequency, groundwater level and salinity), collected traits from 242 individuals (specific leaf area [SLA], whole plant C:N ratio, and dry weights of plant organs) and sampled above-ground biomass as an ecosystem property. We constructed a path model combining environmental parameters, functional traits at community level and above-ground biomass, which was tested against a dependence model using path analysis; model fit was evaluated by structural equation modelling (SEM). Results: The final model showed good consistency with the data and highlights the major role of groundwater level, salinity and nutrient availability as the most important factors influencing biomass allocation in salt marshes. Above-ground living biomass was mostly determined by stem biomass, which was mediated through an allometric allocation of biomass to all other plant organs, including leaf mass. C:N ratio and SLA were the major drivers for dead biomass. Conclusion: We emphasize an indirect link between standing biomass and environmental conditions and recognize stem biomass, plant C:N ratio and SLA as keystone markers of species functioning in determining the relationship between environment and ecosystem properties.

Climate change and justice are so closely associated that many people take it for granted that a global climate treaty should--indeed, must--directly address both issues together. But, in fact, this would be a serious mistake, one that, by dooming effective international limits on greenhouse gases, would actually make the world's poor and developing nations far worse off. This is the provocative and original argument ofClimate Change Justice. Eric Posner and David Weisbach strongly favor both a climate change agreement and efforts to improve economic justice. But they make a powerful case that the best--and possibly only--way to get an effective climate treaty is to exclude measures designed to redistribute wealth or address historical wrongs against underdeveloped countries. In clear language,Climate Change Justiceproposes four basic principles for designing the only kind of climate treaty that will work--a forward-looking agreement that requires every country to make greenhouse--gas reductions but still makes every country better off in its own view. This kind of treaty has the best chance of actually controlling climate change and improving the welfare of people around the world.

O objetivo geral da pesquisa é investigar a relação entre fluxo financeiro e fatores específicos como determinantes da estrutura de capital nas empresas latino-americanas. O constructo teórico tem como hipótese principal o argumento de que as empresas com maiores níveis de geração de fluxo financeiro possuem maiores níveis de endividamento. A pesquisa caracteriza-se como descritiva, documental com abordagem quantitativa, referentes aos anos de 2008 a 2013. Para análise dos dados, emprega-se a Regressão Linear Múltipla com dados em painel. Os resultados evidenciaram que foram rejeitadas as hipóteses alternativas de pesquisa. Entretanto, o conjunto de fatores utilizado na pesquisa apresentou elevados níveis de explicação do nível de endividamento e se configurou como determinante relevante da estrutura de capital das empresas latino-americanas.

Understanding the mechanisms driving biological diversity remains a central problem in ecology and evolutionary biology. Traditional explanations assume that differences in selection pressures lead to different adaptations in geographically separated locations. This book takes a different approach and explores adaptive diversification--diversification rooted in ecological interactions and frequency-dependent selection. In any ecosystem, birth and death rates of individuals are affected by interactions with other individuals. What is an advantageous phenotype therefore depends on the phenotype of other individuals, and it may often be best to be ecologically different from the majority phenotype. Such rare-type advantage is a hallmark of frequency-dependent selection and opens the scope for processes of diversification that require ecological contact rather than geographical isolation.

Mediante una exposición que no pretende ser exhaustiva, este artículo presenta el marco conceptual de tres teorías sobre estructura de capital dominantes en el campo de las finanzas: la teoría de la irrelevancia, la teoría del trade off y la teoría de la jerarquía de las preferencias. Si bien sus postulados--en especial en el caso de la teoría de la irrelevancia--han sido ampliamente difundidos, en estas páginas se dan a conocer otros aspectos fundamentales de las teorías tal como fueron concebidas por sus autores.

The vulnerability and financial pressure of financial systems is a critical subject in light of the economic crisis we are currently facing. This paper defines financial pressure of local governments as the extreme situation characterized by financial imbalances, increasing current expenditure, lack of investment, excessive public debt and debt service. Using multivariate methods this paper develops six indexes that jointly measure the pressure on local public finances in Mexico for the period 2001-2007. These indexes - which by construction are not correlated with each other - capture more than 80% of the variation of public finance variables and show the ranking of each state in relation to other states in Mexico. Among the results we find a trade-off between public investment and balance surpluses and between savings and current expenditure. The thence-obtained set of indexes can be used by local officials to assess the relative condition of their State's public finances in relation to others and by supervisors or regulatory bodies to asses the financial pressure experienced by State governments in Mexico. // ABSTRACT IN SPANISH: La vulnerabilidad y presión de los sistemas financieros es un tema latente en la práctica y estudio de la economía a la luz de la crisis reciente. Este artículo define la presión financiera de los gobiernos estatales como aquella ejercida por el desequilibrio financiero, el incremento del gasto corriente, la falta de inversión, la acumulación excesiva de deuda pública y su servicio. A partir de un análisis multivariado en este artículo se desarrolla seis índices que miden en su conjunto la presión en las finanzas públicas estatales en México de 2001 a 2007. Estos índices, no correlacionados entre sí, captan más de 80% de la variabilidad estadística observada en las finanzas públicas estatales en México y muestran la posición relativa de cada entidad federativa contra el resto de los estados. Entre otros resultados se encuentran factores de finanzas públicas que confirman la existencia de una correspondencia (trade-off) entre inversión pública y superávit y entre el ahorro y el gasto ordinario. El conjunto de indicadores obtenido en este artículo puede ser usado por el funcionario local para comparar la posición relativa de su entidad respecto a otros estados y por el regulador/supervisor para determinar la presión financiera que experimentan los gobiernos subsoberanos en México.

In response to biofuel policies, the impacts of biofuels are very controversial. In particular, biofuels have been universally blamed for recent food price increases. In this paper, we review the recent but growing literature on the topical trade-off : Fuel vs. Food. First, we present biofuel policies as well as the different types of biofuel. Then we analyze the different economic studies dealing with biofuels and their economic impacts on agricultural markets. //ABSTRACT IN FRENCH: En réaction aux politiques de soutien aux biocarburants, de nombreuses voix se sont levées pour alerter des dangers de ce choix de politique énergétique. Les biocarburants sont principalement accusés de créer des tensions sur les marchés agricoles mondiaux en restreignant l'offre de produits alimentaires. Nous analysons les développements économiques récents autour du thème nourriture contre carburant. Afin de mettre en place les termes du débat, nous présentons les politiques de soutien après avoir recensé les différentes catégories de biocarburants. Puis nous analysons les résultats des études économiques visant à mesurer l'impact des biocarburants sur les marchés agricoles. Reproduced by permission of Bibliothèque de Sciences Po

Summary The urban dimension of ecosystem services (ES) is underexposed, while the importance of ES for human well‐being is nowhere as evident as in cities. Urban challenges such as air pollution, noise and heat can be moderated by urban green space (UGS), simultaneously providing multiple other services. However, available methods to quantify ES cannot typically deal with the high spatial and thematic resolution land cover data that are needed to better understand ES supply in the urban context. This study derives methods to quantify and map a bundle of six ES as supplied by UGS, using land cover data with high spatial and thematic resolution, and applies these to the city of Rotterdam, the Netherlands. Land cover data comprise eight classes of UGS. Methods are derived from an evidence base on the importance of UGS types for the supply of each of the six ES that was built using literature review. The evidence base reveals that UGS types differ in their contribution to various ES, although the strength of the evidence varies. However, existing indicators for urban ES often do not discriminate between UGS types. To derive UGS‐specific indicators, we combined methods and evidence from different research contexts (ES, non‐ES, urban, non‐urban). Rotterdam shows high spatial variation in the amount of UGS present, and accounting for this in ES supply reveals that ES bundles depend on UGS composition and configuration. While the contribution of UGS types to ES supply differed markedly with UGS type and ES considered, we demonstrate that synergies rather than trade‐offs exist among the ES analysed. Synthesis and applications. Our findings underline the importance of a careful design of urban green space (UGS) in city planning for ecosystem services (ES) provision. Based on the latest insights on how different UGS provide ES, the methods presented in this study enable a more detailed quantification and mapping of the supply of ES in cities, allowing assessments of current supply of key urban ES and alternative urban designs. Such knowledge is indispensable in the quest for designing healthier and climate‐resilient cities. Our findings underline the importance of a careful design of urban green space (UGS) in city planning for ecosystem services (ES) provision. Based on the latest insights on how different UGS provide ES, the methods presented in this study enable a more detailed quantification and mapping of the supply of ES in cities, allowing assessments of current supply of key urban ES and alternative urban designs. Such knowledge is indispensable in the quest for designing healthier and climate‐resilient cities.

Des statistiques non-paramétriques sont construites, pour les tests intervenant dans l'analyse de la variance, en remplaçant les observations originales par les observations normales occupant les mêmes rangs que les observations originales qu'elles remplacent, puis en calculant le numérateur des statistiques t de Student et F de Snedecor. Ces statistiques non-paramétriques ont des répartitions normales ou de χ 2 lorsque l'hypothèse nulle est vraie. Elles ont l'avantage sur les autres statistiques non-paramétriques que les régions de rejet peuvent être obtenues facilement et que l'on n'a pas besoin d'utiliser les tests randomisés pour obtenir les seuils de signification exacts. L'efficacité relative asymptotique de ces \"statistiques de variables normales\" par rapport aux statistiques classiques t et F dépend de la manière de les calculer: si la taille de l'échantillon dans chaque parcelle tend vers l'infini, alors les statistiques proposées sont asymptotiquement uniformément plus efficaces que les statistiques t et F pour certains modèles linéaires généraux, tandis qu'il n'en est pas toujours ainsi lorsque le nombre d'observations dans chaque parcelle est fixé. On montre aussi que pour certains modèles linéaires l'efficacité relative asymptotique des \"statistiques de variables normales\" par rapport aux statistiques obtenues en remplaçant les observations originales par leurs rangs et en calculant les statistiques t et F, est égale à l'efficacité relative asymptotique de la statistique de Fisher et Yates par rapport à la statistique de Wilcoxon pour le \"problème de deux-échantillons\". Enfin la puissance pour les petits échantillons est estimée par la méthode de Monte-Carlo.