824 resultados para Critical factors
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Attempts are made to measure activities of both components of a binary alloy (A�B) at 650 K using a solid-state galvanic cell incorporating a new composite solid electrolyte. Since the ionic conductivity of the composite solid electrolyte is three orders of magnitude higher than that of pure CaF2, the cell can be operated at lower temperatures. The alloy phase is equilibrated in separate experiments with flourides of each component and fluorine potential is measured. The mixture of the alloy (A�B) and the fluoride of the more reactive component (BF2) is stable, while (A�B) + AF2 mixture is metastable, Factors governing the possible use of metastable equilibria have been elucidated in this study. In the Co�Ni system, where the difference in Gibbs energies of formation of the fluorides is 21.4 kJ/mol, emf of the cell with metastable phases at the electrode is constant for periods ranging from 90 to 160 ks depending on alloy composition. Subsequently, the emf decreases because of the onset of the displacement reaction. In the Ni�Mn system, measurement of the activity of Ni using metastable equilibria is not fully successful at 650 K because of the large driving force for the displacement reaction (208.8 kJ/mol). Critical factors in the application of metastable equilibria are the driving force for displacement reaction and diffusion coefficients in both the alloy and fluoride solid solution.
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Household-level water treatment and safe storage systems (HWTS) are simple, local, user-friendly, and low cost options to improve drinking water quality at the point of use. However, despite conclusive evidence of the health and economic benefits of HWTS, and promotion efforts in over 50 countries in the past 20 years, implementation outcomes have been slow, reaching only 5-10 million regular users. This study attempts to understand the barriers and drivers affecting HWTS implementation. Using a case study example of a biosand filter program in southern India, system dynamics modelling is shown to be a useful tool to map the inter-relationships of different critical factors and to understand the dissemination dynamics. It is found that the co-existence of expanding quickly and achieving financial sustainability appears to be difficult to achieve under the current program structure.
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Abstract: Starting in the 1980s, household-level water treatment and safe storage systems (HWTS) have been developed as simple, local, user-friendly, and low cost options to improve drinking water quality at the point of use. However, despite conclusive evidence of the health and economic benefits of HWTS, and promotion efforts in over 50 countries in the past 20 years, implementation outcomes have been slow, reaching only 5-10 million regular users. This study attempts to understand the barriers and drivers affecting HWTS implementation. Although existing literature related to HWTS and innovation diffusion theories proposed ample critical factors and recommendations, there is a lack of holistic and systemic approach to integrate these findings. It is proposed that system dynamics modelling can be a promising tool to map the inter-relationships of different critical factors and to understand the structure of HWTS dissemination process, which may lead to identifying high impact, leveraged mitigation strategies to scale-up HWTS adoption and sustained use.
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Key Messages [pdf, 2.5 Mb] Climate Information Gaps Ocean Productivity Information gaps Living Marine Resources Information gaps Climate [pdf, 1.8 Mb] Productivity [pdf, 5.2 Mb] Nutrients Phytoplankton Zooplankton Living Resources [pdf, 10 Mb] Subarctic coastal systems Central oceanic gyres Temperate coastal and oceanic systems Marine mammals The Human Population [pdf, 5 Mb] Contaminants and Habitat Modifications Aquaculture Knowledge Gaps Glossary Ocean and Climate Changes [pdf, 4.1Mb] Highlights Introduction Atmospheric Indices Change in 1998/99 Comparison of Atmospheric Indices Authorship Yellow Sea / East China Sea [pdf, 2.3 Mb] Highlights Background Status and Trends Hydrography Chemistry Plankton Benthos Fish and invertebrates Marine birds and mammals Issues Critical factors causing change Authorship Japan/East Sea [pdf, 3.3 Mb] Highlights Background Status and Trends Hydrography Chemistry Plankton Fish and Invertebrates Marine Birds and Mammals Critical factors causing change Issues Authorship Okhotsk Sea [pdf, 1.7 Mb] Background Status and Trends Climate Hydrography Chemistry Plankton Fish and Invertebrates Marine Birds and Mammals Issues Critical factors causing change Authorship Oyashio / Kuroshio [pdf, 4.5 Mb] Highlights Background Status and Trends Hydrography Plankton Fish and Invertebrates Marine Birds and Mammals Issues Authorship Western Subarctic Gyre [pdf, 4.5 Mb] Highlights Background Status and Trends Hydrography Chemistry Plankton Fish and Invertebrates Marine Birds and Mammals Issues Authorship Bering Sea [pdf, 2.2 Mb] Highlights Background Status and Trends Hydrography Chemistry Plankton Fish and Invertebrates Marine Birds and Mammals Critical Factors Causing Change Issues Authorship Gulf of Alaska [pdf, 2.6 Mb] Highlights Background Status and trends Hydrography Chemistry Plankton Fish and Invertebrates Marine birds and mammals Critical factors causing change Issues Authorship California Current [pdf, 2.7 Mb] Highlights Background Status and Trends Hydrography Chemistry Plankton Fish and Invertebrates Marine Birds and Mammals Critical Factors Causing Change Issues Authorship Gulf of California [pdf, 1.7 Mb] Highlights Background Status and Trends Hydrography Chemistry Plankton Fisheries Marine Birds and Mammals Critical Factors Causing Change Issues Authorship Transition Zone [pdf, 2.5 Mb] Background Status and Trends Hydrography Chemistry Plankton Fish and Invertebrates Marine Birds and Mammals Issues Authorship Tuna [pdf, 1.5 Mb] Highlights Background Pacific bluefin tuna Albacore tuna Status and trends Ecosystem model and climate forcing Authorship Pacific halibut [pdf, 1.1 Mb] Background The Fishery Climate Influences Authorship Pacific salmon [Updated, pdf, 0.4 Mb] Background Status and Trends Washington, Oregon, and California British Columbia Southeast Alaska Central Alaska Western Alaska Russia Japan Authorship References [pdf, 0.5 Mb]
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Macroeconomic growth and the development of sustainable business activities are interrelated. In Lagos State, aquaculture is a marginal economic activity thriving mainly on a semi-intensive level. Notwithstanding the available potentials for the development of successful commercial aquaculture enterprises in the state, the transformation to a full-flagged industry continues to be undetermined by certain critical factors. Feasible development strategies may be sought in increasing all stakeholders' capacity in the formulation of policies, plans and regulations, a complete separation of aquaculture from the capture fisheries in administrative structure and policy; the adoption of precautionary approach; provision of economic incentives to enhance private investments and increase output,respectively
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This study examined the technical efficiency in artisanal fisheries in Lagos State of Nigeria. The study employed a two stage random sampling procedure for the selection of 120 respondents. The analytical techniques involved descriptive statistics and estimation of technical efficiency following maximum likelihood estimation (MLE) procedure available in FRONTIER 4.1. The MLE result of the stochastic frontier production function showed that hired labour, cost of repair and capital items are critical factors that influences productivity of artisanal fishermen with the coefficient of hired labour being highly elastic. This implies that employing more labour will significantly increase the catch in the study area. The predicted farm efficiency with an average value of 0.92 showed that there is a marginal potential of about 8 percent to increase the catch, hence the income of the fishermen. The study further examined the factors that influence productivity of fishermen in the study area. Year of education, mode of operation and frequency of fishing have important implication on the technical efficiency of fishermen in the study area.
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We report a novel phase separation phenomenon observed in the growth of ternary In(x)Ga(1-x)As nanowires by metalorganic chemical vapor deposition. A spontaneous formation of core-shell nanowires is investigated by cross-sectional transmission electron microscopy, revealing the compositional complexity within the ternary nanowires. It has been found that for In(x)Ga(1-x)As nanowires high precursor flow rates generate ternary In(x)Ga(1-x)As cores with In-rich shells, while low precursor flow rates produce binary GaAs cores with ternary In(x)Ga(1-x)As shells. First-principle calculations combined with thermodynamic considerations suggest that this phenomenon is due to competitive alloying of different group-III elements with Au catalysts, and variations in elemental concentrations of group-III materials in the catalyst under different precursor flow rates. This study shows that precursor flow rates are critical factors for manipulating Au catalysts to produce nanowires of desired composition.
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Oceanographic conditions and transport processes are often critical factors that affect the early growth, survival and recruitment of marine fishes. Sagittal otoliths were analysed to determine age and early growth for 381 jack mackerel (Trachurus japonicus) juveniles from Sagami Bay on the Pacific coast of Japan. Two separate hatching periods ( December and February-March) were identified. They originated from the spawning grounds in the East China Sea. Early growth and developmental rates of December-hatching fish were lower than those for February-March-hatching fish. It is likely that these differences were determined in the Kuroshio Current during transport from the spawning grounds to Sagami Bay, and the lower December water temperatures in the bay. Origin and hatch dates of juveniles in Sagami Bay were in contrast to previous research on Fukawa Bay, where April-or-later-hatching fish from spawning grounds in the coastal waters of southern Japan constituted about half of the juvenile population. Management of these two jack mackerel stocks needs to consider these differences in hatch date composition and spawning origins, as these differences could affect early growth and subsequent mortality.
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The development of sustainable hydrogen production is a key target in the further facilitation of a hydrogen economy. Solar hydrogen generation through the photolytic splitting of water sensitised by semiconductor materials is attractive as it is both renewable and does not lead to problematic by-products, unlike current hydrogen sources such as natural gas. Consequently, the development of these semiconductor materials has undergone considerable research since their discovery over 30 years ago and it would seem prescient to review the more practical results of this research. Among the critical factors influencing the choice of semiconductor material for photoelectrolysis of water are the band-gap energies, flat band potentials and stability towards photocorrosion; the latter of these points directs us to focus on metal oxides. Careful design of thin films of photocatalyst material can eliminate potential routes of losses in performance, i.e., recombination at grain boundaries. Methods to overcome these problems are discussed such as coupling a photoanode for photolysis of water to a photovoltaic cell in a 'tandem cell' device.
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En los últimos años han aparecido nuevas formas de turismo más sostenibles, donde existen elementos relacionados con el descanso, el disfrute y la protección del medio ambiente o el conocimiento de la cultura local, a través de políticas que favorecen la sostenibilidad del destino. En este sentido, el ecoturismo se configura como una tipología turística que se desarrolla en contacto con la naturaleza. Este turismo ayuda a mejorar el desarrollo socioeconómico de las comunidades locales, a la vez, que fomenta la conservación de los recursos naturales y el respeto hacia el medio ambiente. Aunque, esta tipología de turismo también genera importantes impactos negativos. El objetivo principal de esta investigación es analizar los impactos socioeconómicos, culturales y medioambientales percibidos por el ecoturismo por parte de los residentes de comunidades rurales de República Dominicana. La técnica de recolección de datos utilizada ha consistido en un cuestionario. Entre las principales conclusiones, cabe destacar que actualmente no se perciben impactos negativos, pero si hay una serie de elementos que hay que ir considerando, con la finalidad de que no se conviertan en un impacto a corto plazo para la comunidad rural.
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Considering the confined and complex nature of urban construction projects, labor productivity is one of the key factors attributing to project success. With the proliferation of sub-contracted labor, there is a necessity to consider the ramifications of this practice to the sector. This research aims to outline how project managers can optimise productivity levels of sub-contracted labor in urban construction projects, by addressing the barriers that most restrict these efficiency levels. A qualitative research approach is employed, incorporating semi-structured interviews based on three case studies from an urban context. The results are scrutinised using mind mapping software and accompanying analytical techniques. The findings from this research indicate that the effective on-site management of sub-contracted labor has a significant impact on the degree of success of an urban development project. The two core barriers to sub-contracted labor productivity are; 1) ineffective supervision of sub-contracted labor, and 2) lack of skilled sub-contracted labor. The implication of this research is that on-site project management play an integral role in the level of productivity achieved by sub-contracted labor in urban development projects. Therefore, on-site management situated in urban, confined construction sites, are encouraged to take heed of the findings herein and address the barriers documented. The value of this research is obtained through consideration of the critical factors; construction management professionals can mitigate such barriers, in order to optimise subcontracted labor productivity on-site.
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PurposeThe selection of suitable outcomes and sample size calculation are critical factors in the design of a randomised controlled trial (RCT). The goal of this study was to identify the range of outcomes and information on sample size calculation in RCTs on geographic atrophy (GA).MethodsWe carried out a systematic review of age-related macular degeneration (AMD) RCTs. We searched MEDLINE, EMBASE, Scopus, Cochrane Library, www.controlled-trials.com, and www.ClinicalTrials.gov. Two independent reviewers screened records. One reviewer collected data and the second reviewer appraised 10% of collected data. We scanned references lists of selected papers to include other relevant RCTs.ResultsLiterature and registry search identified 3816 abstracts of journal articles and 493 records from trial registries. From a total of 177 RCTs on all types of AMD, 23 RCTs on GA were included. Eighty-one clinical outcomes were identified. Visual acuity (VA) was the most frequently used outcome, presented in 18 out of 23 RCTs and followed by the measures of lesion area. For sample size analysis, 8 GA RCTs were included. None of them provided sufficient Information on sample size calculations.ConclusionsThis systematic review illustrates a lack of standardisation in terms of outcome reporting in GA trials and issues regarding sample size calculation. These limitations significantly hamper attempts to compare outcomes across studies and also perform meta-analyses.
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A gestão de conhecimento é crucial para a competitividade sustentável das organizações. Todavia, a gestão do conhecimento nos centros de investigação universitários tem sido alvo de uma parca atenção nas práticas destas instituições e a literatura sobre este tema também é escassa. O objetivo deste estudo é o de identificar as barreiras e os facilitadores em quatro processos de conhecimento (aquisição; criação; partilha; transferência de conhecimento), em centros de investigação universitários. Foi feito um estudo exploratório, sendo realizadas vinte e uma entrevistas a diretores, investigadores principais e investigadores juniores, em sete centros de investigação, em duas universidades portuguesas. Os resultados obtidos são: a) as principais barreiras mencionadas pelos participantes são: fraco capital social organizacional interno; deficientes mecanismos de implementação da estratégia nacional; fraco capital social/relacional individual; fraca cultura orientada para os resultados.b) os principais facilitadores mencionados são: forte capital social organizacional externo; forte capital social organizacional interno; boas práticas de formação; forte cultura organizacional orientada para os resultados e adequada estratégia nacional. Em síntese, o estudo sugere que as variáveis de natureza individual e socioorganizacional são relevantes para a produção de conhecimento nestas organizações. A liderança dos centros de investigação tem que ter em linha de conta estes fatores críticos. Adicionalmente não pode descurar o alinhamento das tecnologias com os processos de conhecimento, visto estas serem considerados um suporte do trabalho dos investigadores. Porque as organizações são entidades porosas, é necessário ainda uma liderança atenta aos fatores contextuais para que a gestão do conhecimento seja eficaz.
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Este trabalho de investigação foi realizado com o objetivo geral de se descobrir quais são os Fatores Críticos de Sucesso e os aspectos chaves de qualidade e sustentabilidade, a serem considerados no ensino de Engenharia de Produção em um IES privada no Brasil. No presente estudo de caso executou-se uma revisão teórica sistemática nas áreas temáticas da pesquisa, que propiciou a criação de um framework que define os 7 Fatores Críticos de Sucesso ao ensino de Engenharia de Produção, apontando sua divisão nas áreas de qualidade e sustentabilidade, e, por fim, a subdivisão em 6 subáreas de ações operacionais a serem consideradas pela gestão de IES para alcançar melhorias de desempenho em suas atividades. Posteriormente ao levantamento teórico, foi realizado o estudo de caso propriamente dito, que dividiu-se em duas etapas, uma qualitativa e uma quantitativa. Na primeira elaborou-se um roteiro de entrevista em profundidade aplicada a um terço do corpo docente do curso em estudo, captando a impressão destes sobre as temáticas em estudo voltadas à execução de suas atividades. Os dados obtidos foram organizados com o auxílio do software WebQDA, gerando ideias do que deve ser trabalhado para melhorar as condições e resultados do referido curso. A etapa quantitativa foi iniciada com a elaboração de um questionário on-line, desenvolvido a partir do enquadramento teórico e da informação obtida na parte qualitativa do estudo, que envolveu respostas de cerca de dois terços dos discentes de Engenharia de Produção. A informação foi recolhida através de um formulário disponibilizado pelo googledocs, e os resultados foram analisados com o auxílio do software SPSS, permitindo conhecer as expectativas e percepções dos alunos e, consequentemente, os gaps provenientes a serem trabalhados. Finalmente, o estudo revelou que para aspectos de qualidade, os pontos de tangibilidade, como infraestrutura geral, laboratórios técnicos específicos, cantina e biblioteca, precisam ser melhorados, e, para aspectos de sustentabilidade, surge a necessidade de melhorar as formas de divulgação do curso, captação de alunos e propostas para a retenção dos mesmos para outros cursos e projetos da IES. Deste modo, o trabalho desenvolvido atingiu seu objetivo e se mostrou válido para aplicações na IES e em outros cursos da mesma (com as devidas adaptações). Fica como recomendação final aplicar o estudo periodicamente para se captar as mudanças situacionais que ocorrerem, manter um controle eficiente dos aspectos estudados e gerar melhorias contínuas no curso estudado e na própria IES.
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O objetivo do presente relatório de estágio é clarificar e sistematizar alguns conceitos associados à Avaliação Ambiental Estratégica (AAE) de Instrumentos de Gestão Territorial (IGT), e expor a aplicação desta ferramenta a um Plano Diretor Municipal (PDM). A Avaliação Ambiental Estratégica é um instrumento de avaliação da política de ambiente aplicado ao processo de planeamento para garantir que as considerações ambientais são integradas, a par das questões económicas e sociais, durante a fase de elaboração de planos e programas e antes da sua aprovação, com a finalidade de promover a adoção de soluções mais sustentáveis e o estabelecimento de diretrizes de seguimento que minimizem os impactes negativos. Em Portugal, a aplicação desta ferramenta de avaliação é um procedimento obrigatório desde a transposição da Diretiva 2001/42/CE, de 27 de junho para a ordem jurídica interna pelo Decreto-Lei n.º 232/2007, de 15 de junho. O processo de AAE desenvolve-se em três fases essenciais: o estabelecimento dos fatores críticos para a decisão, a avaliação e o seguimento. Este relatório de estágio analisa a aplicação da AAE à 1ª revisão do Plano Diretor Municipal de Castelo de Vide, onde se conclui que a identificação das oportunidades e riscos resultantes da estratégia de desenvolvimento territorial contribui para a prossecução do desenvolvimento sustentável e para uma tomada de decisão mais adequada.