913 resultados para 24-Ethyl-5alpha-cholest-22-en-3beta-ol flux


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The investigations on the fecundity of cod from different areas of the Baltic Sea started in 1992. The samples were collected in ICES Sub-divisions 25 (Bornholm Sea). 24 (Arkona Sea) and 22 (Mecklenburg and Kiel Bay). This article surnmarizes the results of 435 analysed gonads from females of age groups 1 to 8 with total length of 24 - 116 cm of the years 1992 to 1995. The gonads were prepared and analysed according to the methods which were deseribed in Bleil and Oeberst (1993). The aim of the investigations is to estimate the reproduction potential of cod for different areas and years. For this reason the absolute and relative fecundity were analysed for estimating the dependence on the total length, for age groups and the weight of females. These data were estimated for the populations Gadus morhua morhua and Gadus morhua callarias. Preliminary results have shown that the absolute fecundity (fabs) is dependent on whole weight of the females. The influence of sub-divisions (SD) and years to the fecundity are very low. Additional to this data was calculated the population fecundity for the western Baltic Sea stock (SD 22 and 24). The numbers of produced ripe eggs within the western Baltic were estimated with 4055.59 x 10(9) for 1993 and 6949.85 x 10(9) for 1994.

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In 1990, "BICER" or the Baikal International Centre for Ecological Research was created to foster collaborative research on Lake Baikal. The British effort in BICER was initiated and is administered by the Royal Society, London. Much of the on-going research effort is now focussed on environmental change, as there is increasing concern about recent changes in the lake's unique ecosystem that could be linked with the effects of water pollution from catchment effluents. Monitoring studies of the phytoplankton in Lake Baikal's southern basin indicate that several species have increased in abundance since the mid-70's. Diatoms in Lake Baikal sediments are also being studied.

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A major survey of the River Endrick was carried out in 1959-60. This survey was repeated three decades later in 1989-90 and comparisons were made of the fauna at the two times of sampling. During both surveys, photographs were taken of all the sampling sites and the objective of the present paper is to compare some of these photographs and discuss the value of photography in studies of river ecology. The sites used for photographic comparison were not chosen originally for that purpose but as appropriate places on the river from source to mouth to study its ecology. The pairs of photos now available have proved of interest and value and some lessons have been learned in relation to the selection of sites for any future photographic studies. Ideally photos should be taken in more than one season of the year as much of the river can be obscured by riparian trees and shrubs during the vegetative season. The exact position from which each photograph is taken is also a major factor to be considered.

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Megacyclops viridis Jurine, noticed in Lago Maggiore in 1912 by De Marchi from the littoral vegetation of Pallanza, is a normal member of the littoral plankton of the lake. The subgenus Megacyclops, created by Kiefer in his revision of the viridis-vernalis group, contains european and american species some of which are today considered as varieties of the species viridis. This paper examines morphology and of the distribution of the Italian viridis in Lake Maggiore.

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These minutes report on colloquium on the methodology of radiation measurement under water. The meeting was held on 3-5 January 1957, at the Biological Station, Lunz, Austria. The participants of the colloquium discussed various methodologies of radiation measurements, basic methods such as Secchi Disc and underwater photometer as well as specialist equipment like the absolute radiation apparatus.

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RIVPACS (River InVertebrate Prediction And Classification System) is a software package developed by the Institute of Freshwater Ecology (IFE). The primary application is to assess the biological quality of rivers within the UK. RIVPACS offers site-specific predictions of the macroinvertebrate fauna to be expected in the absence of major environmental stress. The expected fauna is derived by RIVPACS using a small suite of environmental characteristics. The biological evaluation is then obtained by comparing the fauna observed at the site with the expected fauna. RIVPACS also includes a site classification based on the macroinvertebrate fauna of the component reference sites. New sites, judged by their fauna to be of high biological quality, may be allocated to classification groups within the fixed RIVPACS classification. This has potential for evaluating sites for conservation. In this chapter, the origins and history of the RIVPACS approach are described, including major scientific and operational developments over the life of the project. RIVPACS III is described in detail and predictions at different taxonomic levels are demonstrated. The value of the reference dataset for river management and conservation is examined, and the chapter concludes with a brief consideration of some future challenges.

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[EN] The aim of this paper is to study systematic liquidity at the Euronext Lisbon Stock Exchange. The motivation for this research is provided by the growing interest in financial literature about stock liquidity and the implications of commonality in liquidity for asset pricing since it could represent a source of non-diversifiable risk. Namely, it is analysed whether there exist common factors that drive the variation in individual stock liquidity and the causes of the inter-temporal variation of aggregate liquidity. Monthly data for the period between January 1988 and December 2011 is used to compute some of the most used proxies for liquidity: bid-ask spreads, turnover rate, trading volume, proportion of zero returns and the illiquidity ratio. Following Chordia et al. (2000) methodology, some evidence of commonality in liquidity is found in the Portuguese stock market when the proportion of zero returns is used as a measure of liquidity. In relation to the factors that drive the inter-temporal variation of the Portuguese stock market liquidity, the results obtained within a VAR framework suggest that changes in real economy activity, monetary policy (proxied by changes in monetary aggregate M1) and stock market returns play an important role as determinants of commonality in liquidity.

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[ES]Actualmente en las empresas a la preocupación por los resultados económicos se le debe sumar la preocupación por la consecución de resultados que permitan satisfacer las expectativas y necesidades de los grupos de interés o “stakeholders”. Una de las herramientas que las organizaciones emplean para ello es la utilización de los estándares de sistemas de gestión, tales como las normas ISO 9001:2008, ISO 14001:2004 y OHSAS 18001:2007. Recientemente numerosas empresas están optando por la integración de dichos sistemas con el objetivo de crear sinergias: reducir costes, eliminar duplicidades etc. En este trabajo, en primer lugar, se analizarán los diferentes modos de implantación, las motivaciones por las cuales las empresas se inclinan por la integración y las principales ventajas y dificultades de llevar a cabo tal proceso. En segundo lugar, se presentará y analizará el caso concreto de la empresa Gamesa, desde su decisión de integrar los sistemas de gestión hasta los resultados obtenidos.

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[ES]Hoy en día los vehículos usados en la extracción de sangre utilizan un motor de combustión interna, no solamente para sus desplazamientos, sino también para generar electricidad con la que poder utilizar todos los aparatos del interior. Como consecuencia, el autobús es una fuente importante de ruidos y contaminación, ya que el motor diesel está funcionando durante las largas paradas en las que se realiza dicha actividad. El objetivo del proyecto es diseñar un sistema innovador basado en pilas de combustible que sirva para alimentar todos los equipos y dispositivos, evitando el ruido, las vibraciones y los gases contaminantes. Para ello y en primer lugar, será necesario estimar el consumo total del autobús. Tras esto, también se tomarán una serie de decisiones con el fin de mejorar la eficiencia energética del autobús. Finalmente, se hará un diseño del sistema energético, el cual debe incluir una pila de combustible, junto con todos sus sistemas asociados, y todas las especificaciones.

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