991 resultados para E49 - Other
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Sexual eukaryotes generate gametes using a specialized cell division called meiosis that serves both to halve the number of chromosomes and to reshuffle genetic variation present in the parent. The nature and mechanism of the meiotic cell division in plants and its effect on genetic variation are reviewed here. As flowers are the site of meiosis and fertilization in angiosperms, meiotic control will be considered within this developmental context. Finally, we review what is known about the control of meiosis in green algae and non-flowering land plants and discuss evolutionary transitions relating to meiosis that have occurred in the lineages giving rise to the angiosperms.
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In the life of the Law School, focus on the “visual” can operate at three different levels: learning, teaching, and examining (legal concepts). My main interest in this paper is to explore the latter level, “examining”, broadly considered so as to encompass evaluation in general. Furthermore, that interest is pinned down here to the area of constitutional rights and human rights in general, even though the conclusions reached can (and should) likely be extrapolated to other areas of the law... In effect, the first logical step regarding the relevance of the visual approach has to do with using it yourself when you study —assuming that you came to the conclusion that you are a “visual learner”. As you know, VARK theorists propose a quadripartite classification of learners. The acronym VARK stands for Visual, Aural, Read/write, and Kinesthetic sensory modalities that are used for learning information. This model was designed in the late 80s by Neil Fleming and it has received some acceptance and a lot of attention...
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ENGLISH: In this paper, a method of analysis described by Gulland (1963) has been used to estimate the fishing mortality rates of tagged yellowfin and skipjack tuna for specific areas and years. Fishing mortality rates obtained for tagged tunas will also represent those for the entire population from which the tagged fishes were drawn, provided the assumptions used and corrections made for these analyses are valid. Total mortality rates of tagged fishes have also been computed. These are not assumed to be directly equivalent to the total mortality rates of the untagged populations,since tagged fishes are subject to additional types of attrition. These additional sources of mortality are also examined in this study. SPANISH: En el presente trabajo se ha usado un método de análisis descrito por Gulland (1963), para estimar las tasas de mortalidad de pesca de los atunes aleta amarilla y barrilete marcados en áreas y años específicos. Las tasas de mortalidad de pesca obtenidas en atunes marcados representarán también las de toda la población, de la cual fueron extraídos, previendo que las suposiciones usadas y las correcciones hechas para estos análisis sean válidas. Las tasas de mortalidad total de los peces marcados también han sido computadas. No se supone que éstas sean directamente equivalentes a las tasas de mortalidad total de las poblaciones no marcadas, ya que los peces marcados están sujetos también a otros tipos de pérdida. Estas otras causas de mortalidad son examinadas también en el presente estudio.
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Red drum is one ofthe most popular species sought by anglers in Florida Bay, yet juveniles are rarely encountered. We evaluated Florida Bay as a nursery area for red drum by sampling for recently-settled late larvae in basin areas within the bay with an epi-benthic sled at six stations in November 2000, and at seven stations during December 2000 through February 2001. In November 2000 we surveyed potential sampling sites in quiet backwaters adjacent to mangroves for juvenile red drum. A total of 202 sites were sampled mainly in northern Florida Bay and adjacent waters with a cast net. We collected only one recently-settled red drum larvae and no juveniles. Obviously the sites that we sampled in Florida Bay and adjacent waters are not nursery habitat for this valuable species. Sled collections were dominated by bay anchovy, Anchoa mitchilli, but densities were biased by one collection. Five small resident species were among the dominant species: rainwater killifish, Lucania parva; dusky pipefish, Syngnathus floridae; dwarf seahorse, Hippocampus zosterae; and clown goby, Microgobius gulosus. Three species that spawn outside Florida Bay in the GulfofMexico were common: pinfish, Lagodon rhomboides; pigfish, Orthopristis chrysoptera; and silver perch, Bairdiella chrysoura. Twenty-seven species were collected with the cast net. Hardhead silversides (Atherinomorus stipes), bay anchovy, tidewater mojarra (Eucinostomus harengulus), silver jenny (Eucinostomus gula), and goldspotted killifish (Floridichthys carpio) were the most common in cast net collections. Although only one red drum was collected, we were able to: (1) identify mesohaline waters from our cast net sites to test our preliminary assessment that mesohaline habitat might be limited in Florida Bay, (2) document the distribution and abundance of fishes collected by cast net that should enhance our understanding of ichthyofauna in the Northern Subdivision ofFlorida Bay and adjacent waters, and (3) from epibenthic sled collections, describe the habitats, abundance and distribution of recently settled larvae/small juveniles/small resident fishes during late fall and winter. This information should be useful to managers and future research. (PDF contains 34 pages)
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This paper advocates strategies, processes and practices that enable: livelihoods approaches rather than resource-based approaches, ‘direct’ institutional and policy development, rather than ‘project demonstrations’, and support for regional, national and local communications. (Pdf contains 12 pages).
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Established in early 2002, STREAM Vietnam has so far attained a number of good experiences and lessons in using participatory approaches for its work. The Country Office has been able to link to a wide range of stakeholders, and is working hard to build close relationships amongst them, so that institutional entities can better support the livelihoods of poor aquatic resources users, and support disadvantaged groups of people to improve their living standards by themselves. Reservoir fisheries and co-management are at early stage in Vietnam, but in certain places and industries co-management has brought about successful results by involving proactive participation of communities. Situated on the same continent and having many similarities, the interaction in agriculture and fisheries sector between Vietnam and Sri Lanka has brought the two countries closer. Being members of the STREAM family, there are great opportunities for exchange of experiences and lessons towards sustainable management of reservoir resources. (PDF has 11 pages.)
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xix, 213 p.
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Presents a review of the recreational values and economic importance of Maryland Fishing waters. (PDF contains 5 pages)