969 resultados para Reference book


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Galaxies are clusters of millions and billions of stars dynamically stable, with gas, dust and dark matter. They are the biggest isolated objects known in the Universe . Even though they are very complex systems, today we have a clear knowledge about their evolution and about their physical phenomena. Aside from the stellar component there is a gaseous component, principally neutral Hydrogen (HI), and dust that, although is not a significant component in terms of the mass, plays an important role on the absorption phenomena. Finally, cinematic and other kind of observations suggest the existence of a spheric dark matter halo, dominant in terms of mass and more extensive than the barionic component.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Streptococcus pneumoniae serotype 6E has recently been described, but its long-term epidemiology is not well known. From 1981-2013, 704 serogroup 6 clinical isolates were obtained in Gipuzkoa, Basque Country, Spain. All invasive and one in four non-invasive isolates were included. Overall, 75, 97, 51 and 45 serotypes 6A, 6B, 6C and 6E isolates, respectively, were detected. No serotype 6D isolates were identified. The prevalence of serotypes 6E and 6B, but not that of serotypes 6A and 6C, declined after the introduction of pneumococcal conjugate vaccines. Serotype 6E isolates showed the highest resistance rate. Most serotype 6E isolates were ST90.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This study was conducted to determine which of the two major tilapia species in freshwater capture fisheries in Ghana, Oreochromis niloticus or Sarotherodon galilaeus, is more suitable for breed improvement and pond culture. It compares traits of economic importance, including seed output, specific growth rate, survival and sex ratios following androgen sex reversal. The results of the study showed that the aquaculture potential of S. galilaeus compares favorably with that of O. niloticus. However, S. galilaeus may be preferred because the males and females have an equal growth rate, which allows for manual sorting to raise both sexes in monosex culture, an inexpensive appropriate technology that an ordinary smallscale fish farmer can apply.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The 1987-1995 length composition of quarterly catches of Scomberomorus commerson (Lacepede 1800) was analyzed to determine various biological reference points for management purposes. These include: fishing mortality producing maximum yield-per-recruit in weight (F sub(max)), fishing mortality producing 50% relative mean mature biomass (F sub(50)), and fishing mortality producing recruits that would exactly replace their parent stock (F sub(rep)). F sub(max) provided misleading suggestions to increase fishing mortality on the stock which is currently at a low level. On the other hand, both F sub(50) and F sub(rep) provided acceptable results, suggesting reduction on the current fishing mortality by 17-40%.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A simple cohort model was used as the basis for selecting the appropriate periodicity and number of separate unit areas in a rotating harvest scheme for a sedentary species, the red coral, Corallium rubrum, in the General Fisheries Management Council for the Mediterranean area. The rotation period in years, and hence the minimum number of unit areas involved, was determined on the basis of the time to maximum biomass by a simple calculation of the yield-per-recruit type, requiring a knowledge of natural mortality and growth rates. Other criteria may be more important, however, and in general for a long-lived species, will result in shorter rotation periods. These criteria may include economic factors, criteria based on the preferred size or quality of product, or criteria that take into account the cumulative risk of illegal fishing of closed areas with time, hence the growing cost of enforcement as harvestable product accumulates. For red coral, although maximum biomass is predicted to be reached after some 15-44 years, the above considerations suggest that a rotation period ofsome 9-15 years would be close to optimal, taking into account a range ofthe above considerations. This article discusses the relative merits of rotating harvest schemes in contrast to quota management for sedentary and semi-sedentary resources or geographically isolated substocks ofa mobile resource, and concludes that this approach may have considerable potential as an alternative approach to resource management.

Relevância:

20.00% 20.00%

Publicador:

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Buscando compreender o que seria e a própria possibilidade de uma experiência de existência de modo autêntico, o presente trabalho busca apresentar diferentes construções de tal experiência, escolhidas principalmente pela proximidade temática e do contexto de produção. No campo da filosofia, será apresentada a construção realizada pelo filósofo Martin Heidegger em Ser e Tempo, enquanto que no campo da literatura serão analisados traços das construções presentes em duas obras de Hermann Hesse O Lobo da Estepe e Sidarta e em duas obras de Clarice Lispector Uma Aprendizagem ou O Livro dos Prazeres e A Paixão Segundo G.H. Ele está dividido em três partes. A primeira refere-se à construção da experiência de existência autêntica em Ser e Tempo. Em seguida, serão analisados os quatro romances eleitos utilizando como referência, mas não se limitando a, conceitos heideggarianos. Por fim, será realizada uma análise comparativa, quando serão contrapostas as ferramentas utilizadas em cada romance para apresentar tal experiência, e então alguns desdobramentos possíveis serão apresentados. Como principal questão que liga as obras estudadas, pode-se perceber que em todas elas está presente o ser quem se é, modo no qual ocorre uma abertura própria do ser que nós mesmos somos

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Muitos estudos buscam tentar prever o retorno potencial sobre portfólios de ações, com intuito de obter melhor rentabilidade sobre o capital aplicado. Diversas modelagens já foram utilizadas, sendo que as mais conhecidas são as que relacionam o risco com o retorno. Nesta linha destacam-se a Teoria de Carteiras proposta por Markowitz, e o CAPM de Sharpe. Através destas teorias entende-se a questão da influência da covariância dos retornos e que para um melhor desempenho de uma carteira, não é suficiente avaliar cada ativo individualmente. Por outro lado, diversas críticas em relação ao CAPM, vêm ensejando estudos complementares na busca de outras variáveis que melhorem os métodos de seleção de ativos. Fama e French (1993) fizeram um estudo com variáveis complementares em relação ao beta do CAPM, utilizando o tamanho e a relação Book to Market, conseguindo resultados melhores que o CAPM tradicional. O presente estudo leva em conta a questão do reinvestimento do lucro gerado e utilizando o modelo de Gordon propõe uma variável de classificação de empresas de crescimento e empresas valor, conceito já utilizado na literatura de finanças.Com base nesta variável montam-se carteiras de ações entre os anos de 2005 e 2012 e observa-se que é possível obter ganhos com a lógica proposta. Ao longo do período seria possível obter com as carteiras selecionadas ganhos de até 107,85% contra os retornos de 55,58% das carteiras com todos os ativos. Organizamos os mesmos ativos pela ótica da relação Book to Market as quais obtiveram retorno total do período de 90,42%. Apesar de notar uma mudança clara de comportamento, onde apenas nos quatro primeiros anos do estudo as carteiras com empresas value são superiores e nos quatro últimos períodos as carteiras de empresas growth são as melhores. Estes resultados são compatíveis com os resultados de Braga e Leal (2000), e Mescolin, Martinelli Braga e da Costa Jr. (1997), verificando um melhor desempenho para as empresas value.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This is the episodic variations in stream water chemistry associated with acid rainfall and run-off and the effect on aquatic ecosystems, with particular reference to fish populations in North West England produced by the North West Water Authority in 1985. This report looks at the biological, physical and chemical information collected over a five year period from over 100 sites on upland streams in the North West Region of which drained rocks of low buffering capacity. In both Lake District and South Pennine sites striking differences were found between the composition of invertebrate communities inhabiting acid-stressed and less acid-stressed streams. Electric fishing surveys showed that acidic streams (geometric mean pH <5.5) generally had abnormally low densities of salmonids ( < 0 .2m2) and that 0+ fish were very few or absent. The latter indicates recruitment failure. Salmon were more sensitive than trout to low pH.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This is the report on the strategic stock assessment survey of the Colton Beck catchment in 1994 with particular reference to salmonids in Colton Beck, River Ea, River Gilpin and Rusland Pool. This report forms one part of the third year of a triennial survey programme for the South West Cumbria and South Cumbria catchments. It was produced by the National Rivers Authority in 1994. Colton Beck had excellent densities of sea trout (Salmo trutta) and a small population of salmon (Salmo salar) in its lowest reaches. The total productivity was very good throughout the catchment. Stocking of sea trout fry in 1993 has enhanced the population with survivors through to parr probably adding to the scoring of double class A at two sites in the survey in 1994. Stocking was not undertaken in 1994, but the population appears to be maintaining itself at a very high level.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This is the report on the strategic fisheries stock assessment survey of the minor catchments in South West Cumbria 1996 with particular reference to salmonids, produced by North West Water in 1994. The 1996 Minor Catchment survey indicates variations in salmonid production within these catchments. Survey results indicate that production may be reaching its limit in certain areas whilst others are underachieving and others are unsuitable for salmonid production. Trout production within the catchments is higher and more widespread than that of salmon. Water quality levels vary considerably between catchments and intra-annually within individual catchments. The need for selective habitat surveys, with a view to habitat improvement schemes (H.I.S) is discussed. This report formed a basis for subsequent reports, thus, allowing data comparisons and analysis of production level fluctuations. It was the most extensive assessment of these catchments to date, taking into account comparisons with the new National Database on salmonid production in England and Wales.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This is the report on the strategic fisheries stock assessment survey of the River Winster 1995 together with a coarse fish survey in 1994 and reference to the 1995 drought, produced by the Environment Agency North West in 1996. Salmonid production within the Winster catchment was dominated by trout although good densities of salmon juveniles were found on some main river sites. Despite suffering drought conditions for much of 1995, only salmon fry production appeared to have been affected. Coarse fish populations once found in the lower reaches of the Winster appear to have declined to very low levels with no fish sampled. This may be partly due to broken tidal gates allowing saline intrusion. It seems that the lower river was suited to the development of a recreational coarse fishery, now that the gates have been repaired. This report completes the strategic stock assessment surveys planned for the period 1992-1995. It represents the last major catchment that was surveyed to determine the current status of fisheries in the South and South West Cumbria areas.