999 resultados para global hypoellipticity


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Uma dedução dos critérios de multicriticalidade para o cálculo de pontos críticos de qualquer ordem representa a formalização de ideias utilizadas para calcular pontos críticos e tricríticos e ainda amplia tais ideias. De posse desta dedução pode-se compreender os critérios de tricriticalidade e, com isso, através de uma abordagem via problema de otimização global pode-se fazer o cálculo de pontos tricríticos utilizando um método numérico adequado de otimização global. Para evitar um excesso de custo computacional com rotinas numéricas utilizou-se aproximações na forma de diferenças finitas dos termos que compõem a função objetivo. Para simular a relação P v - T optou-se pela equação de estado cúbica de Peng-Robinson e pela regra clássica de fluidos de van der Vaals, para modelagem do problema também se calculou os tensores de ordem 2, 3, 4 e 5 da função do teste de estabilidade. Os resultados obtidos foram comparados com dados experimentais e por resultados obtidos com outros autores que utilizaram métodos numéricos, equação de estado ou abordagem diferente das utilizadas neste trabalho.

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In the past, agricultural researchers tended to ignore the fisheries factor in global food and nutritional security. However, the role of fish is becoming critical as a result of changes in fisheries regimes, income distribution, demand and increasing international trade. Fish has become the fastest growing food commodity in international trade and this is raising concern for the supply of fish for poorer people. As a result, the impact of international trade regimes on fish supply and demand, and the consequences on the availability of fish for developing countries need to be studied. Policies aimed at increasing export earnings are in conflict with those aimed at increasing food security in third world countries. Fisheries policy research will need to focus on three primary areas which have an impact on the marginal and poorer communities of developing countries: increased international demand for low-value fish on the supply of poorer countries; improved aquaculture technologies and productivity on poorer and marginal farmers; and land and water allocation policy on productivity, food security and sustainability across farm, fishery and related sectors. The key to local food security is in the integration of agriculture, aquaculture and natural resources but an important focus on fisheries policy research will be to look at the linkages between societal, economic and natural systems in order to develop adequate and flexible solutions to achieve sustainable use of aquatic resources systems.

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A collaborative project in developing a broad-based coastal management training program in the Philippines is being undertaken by a group of government and nongovernment agencies. It addresses the lack of expertise in planning an implementation for coastal management in the country. The process will be documented to serve as a guide in starting and maintaining the process of collaborative training in coastal management in the region. Other training initiatives are outlined including regional and global efforts.

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The 1997 International Year of the Reef sees the release of ReefBase 2.0: a global database on coral reefs and their resources. It provides the most comprehensive and accessible repository of information to date. Containing information on over 7000 coral reefs in more than 123 countries, ReefBase 2.0 offers an extensive range of time-related data pertaining to coastal tourism, benthic environment ecology, fish population statistics, oceanography, socioeconomics, mariculture, and harvest activities. It also outlines the stresses causing reef degradation as well as management initiatives. Complemented by hundreds of digitized maps provided by the World Conservation Monitoring Centre (WCMC) and over 500 high quality photographs, ReefBase 2.0 is not only an essential tool for coral reef management but also an comprehensive guide for tourists, scuba divers and snorkelers alike. ReefBase has contributed substantially to the success of the International Coral Reef Institute (ICRI) and serves as the official database of the Global Coral Reef Monitoring Network (GCRMN), bringing together an increasing volume of data on coral reef health, management and significance to humanity, and making it widely available. Over the next five years, the information contained within ReefBase will be utilized as an instrument for developing coral reef health assessment criteria, sustainable management criteria, and providing continuously updated summaries of threats endangering coral reefs around the globe. This will be a strong basis for focused corrective action in an attempt to conserve coral reefs and properly manage their resources for future generations.

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Este texto verificou o tema de monitoramento de processos de produção de petróleo em plataformas no mar de forma a propor indicadores globais para monitoramento da funcionalidade dos equipamentos que envolvem estes processos, permitindo a antecipação da tomada de decisão sobre suas eminentes quedas de disponibilidade. Para tal, buscando conhecer as áreas envolvidas na gestão de uma plataforma de petróleo no mar, foram identificados os principais sistemas relacionados ao processo de produção de petróleo e optou-se pelo Sistema de Separação e Tratamento de Óleo para desenvolvimento e validação dos indicadores propostos. O Indicador Global de Funcionalidade Operacional (IGFO) foi desenvolvido a partir dos dados disponíveis para monitoramento dos processos de produção de petróleo, focado nas visões das principais áreas envolvidas na gestão da plataforma. Este indicador foi elaborado com objetivo de simplificar a análise dos processos, permitindo assim aferir o desempenho das ações de monitoramento de processos em plataformas de petróleo, de modo a atuar de forma antecipativa, contribuindo com a identificação e a disseminação das melhores práticas de manutenção preditiva. Neste aspecto, os indicadores na forma de normalização utilizada permitem comparações em diversos níveis, tanto em relação as plataformas dentro de uma empresa, como plataformas de empresas diferentes. Os indicadores globais propostos obtiveram resultados que permitiram avaliar a queda de funcionalidade dos equipamentos do Sistema de Separação e Tratamento de Óleo durante o período avaliado, servindo de base para identificação das causas das falhas destes equipamentos. Assim sendo, pôde-se perceber que a utilização dos indicadores globais identificados pode responder com sucesso às necessidades propostas

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This paper aims to investigate companies' environmental, social, governance (ESG), and financial implications of their commitment to the United Nations Global Compact (UNGC). The focus is placed on companies operating in the three countries with the highest number of UNGC participants: Spain, France, and Japan. The results clearly reveal that adoption of the UNGC often requires an organizational change that fosters stakeholder engagement, ultimately resulting in improvements in companies' ESG performance. Additionally, the results reveal that ESG performance has a significant impact on financial performance for companies that adopted the principles of the UNGC. These findings provide both non-financial and financial incentives to companies to commit to this voluntary corporate social responsibility (CSR) initiative, which will have important implications on companies' strategic management policies that aim to foster sustainable businesses and community development. Finally, the linkages between the UNGC-committed companies' ESG and financial performance may be influenced by geographical spread, mainly due to the appearance of differences in the institutional, societal, and cultural settings.

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ReefBase a global database of coral reefs systems and their resources was initiated at International Center for Living Aquatic Resources Management (ICLARM), Philippines in November 1993. The CEC has provided funding for the first two years and the database was developed in collaboration with the World Conservation Monitoring Centre in Cambridge, UK, as well as other national, regional, and international institutions. The ReefBase project activities and what ICLARM will do to accomplish the project objectives are briefly discussed.

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The Pond Dynamics/Aquaculture Collaborative Research Support Program (PDA/CRSP) is a global research network to generate basic science that may be used to advance aquaculture development. One of a family of research programs funded by the United States Agency for International Development (USAID), the CRSP focuses on improving the efficiency of aquaculture systems. The PDA/CRSP began work in 1982 in Thailand, and subsequently in the Philippines, Honduras, the US and, until recently, Rwanda. At all the sites, the goal is the same: to identify constraints to aquaculture production, and to design responses that are environmentally and culturally appropriate. The research network's global experiment has focused on tilapia (Oreochromis niloticus), although some sites have devoted attention to marine shrimp and other locally significant species. Impact of the network's investigations with tilapia is examined in this article.

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Coral bleaching and subsequent mortality represent a major threat to the future health and productivity of coral reefs. However a lack of reliable data on occurrence, severity and other characteristics of bleaching events hampers research on the causes and consequences of this important phenomenon. This article describes a global protocol for monitoring coral bleaching events, which addresses this problem and can be used by people with different levels of expertise and resources.

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As part of a study of genetic variation in the Vietnamese strains of the common carp (Cyprinus carpio L.) using direct DNA sequencing of mitochondrial control and ATPase6/8 gene regions, samples from a number of other countries were analyzed for comparison. Results show that the levels of sequence divergence in common carp is low on a global scale, with the Asian carp having the highest diversity while Koi and European carp are invariant. A genealogical analysis supports a close relationship among Vietnamese, Koi, Chinese Color and, to a lesser extent, European carp. Koi carp appear to have originated from a strain of Chinese red carp. There is considerable scope to extend this research through the analysis of additional samples of carp from around the world, especially from China, in order to generate a comprehensive global genealogy of common carp strains.

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The Asian Fisheries Society and the WorldFish Center conducted the first ever Global Symposium on Gender and Fisheries in Penang, Malaysia, from 30 November to 4 December 2004. The two-day Symposium, held in conjunction with the 7th Asian Fisheries Forum, attracted 30 papers by over 100 authors and strong audience discussions that covered countries from Kiribati, through Asia Pacific, Africa, Europe and to the Arctic. The flavor of the Symposium was of changing traditions and recognition of the contributions of different groups to fisheries.