924 resultados para St. John, Frederick Robert, Sir, b. 1831.
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Ichthyofauna of the coastal «10 m depth) habitat of the South Atlantic Bight were investigated between Cape Fear, North Carolina, and the St. John's River, Florida. Trawl collections from four nonconsecutive seasons in the period July 1980 to December 1982 indicated that the fish community is dominated by the family Sciaenidae, particularly juvenile forms. Spot (Leiostomus xanthurus) and Atlantic croaker (Micropogonias undulatus) were the two most abundant species and dominated catches during all seasons. Atlantic menhaden (Brevoortin tyrannus) was also very abundant, but only seasonally (winter and spring) dominant in the catches. Elasmobranch fIShes, especially rajiforms and carcharinids, contributed to much of the biomass of fishes collected. Total fish abundance was greatest in winter and lowest in summer and was influenced by the seasonality of Atlantic menhaden and Atlantic croaker in the catches. Biomass was highest in spring and lowest in summer, and was influenced by biomass of spot. Fish density ranged from 321 individuals and 12.2 kg per hectare to 746 individuals and 25.2 kg per hectare. Most species ranged widely throughout the bight, and showed some evidence of seasonal migration. Species assemblages were dominated by ubiquitous year-round residents of the coastal waters of the bight. Diversity (H') was highest in summer, and appeared influenced by the evenness of distribution of individuals among species. (PDF file contains 56 pages.)
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Poster presentado en Society for Post-Medieval Archaeology Conference, in St John's, Newfoundland,(Canadá)(June 2010)
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Egeria densa (PLANCH.) ST. JOHN, a submerged plant invader, forms a wide submerged plant zone, particularly along the west coast of the south basin, Lake Biwa. The macrophyte occupies over 82% of the plant zone in the basin and its biomass reaches 93% of the total. The estimated annual net production was approximately 1 kg dry wt./m2 in a dense area, which is about 4.5 times as much as the net production by phytoplankton in an offshore area of the basin. Although the area covered by the macrophyte is only 5.8% of the total of the basin, it produced about one-tenth of the total annual primary production. In the most productive season Egeria produced 46% of the total primary productivity. Thus, the macrophyte never be neglected when one considers the energy flow or material circulation in the basin. This study was initiated in order to clarify the role of submerged macrophytes, particularly E. densa, in Lake Biwa. The following points are reported in this paper: the distribution of macrophytes in the south basin; seasonal change in standing crop of E. densa; seasonal change in values related to production, utilizing a model proposed by Ikushima with its parameters experimentally determined.
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Amphibian declines and extinctions have been documented around the world, often in protected natural areas. Concern for this alarming trend has focused attention on the need to document all species of amphibians that occur within U.S. National Parks and to search for any signs that amphibians may be declining. This study, an inventory of amphibian species in Virgin Islands National Park, was conducted from 2001 to 2003. The goals of the project were to create a georeferenced inventory of amphibian species, use new analytical techniques to estimate proportion of sites occupied by each species, look for any signs of amphibian decline (missing species, disease, die-offs, etc.), and to establish a protocol that could be used for future monitoring efforts. Several sampling methods were used to accomplish these goals. Visual encounter surveys and anuran vocalization surveys were conducted in all habitats throughout the park to estimate the proportion of sites or proportion of area occupied (PAO) by amphibian species in each habitat. Line transect methods were used to estimate density of some amphibian species and double observer analysis was used to refine counts based on detection probabilities. Opportunistic collections were used to augment the visual encounter methods for rare species. Data were collected during four sampling periods and every major trail system throughout the park was surveyed. All of the amphibian species believed to occur on St. John were detected during these surveys. One species not previously reported, the Cuban treefrog (Osteopilus septentrionalis), was also added to the species list. That species and two others (Eleutherodactylus coqui and Eleutherodactylus lentus) bring the total number of introduced amphibians on St. John to three. We detected most of the reptile species thought to occur on St. John, but our methods were less suitable for reptiles compared to amphibians. No amphibian species appear to be in decline at this time. We found no evidence of disease or of malformations. Our surveys provide a snapshot picture of the status of the amphibian species, so continued monitoring would be necessary to determine long-term trends, but several potential threats to amphibians were identified. Invasive species, especially the Cuban treefrog, have the potential to decrease populations of native amphibians. Introduced mammalian predators are also a potential threat, especially to the reptiles of St. John, and mammalian grazers might have indirect effects on amphibians and reptiles through habitat modification. Finally, loss of habitat to development outside the park boundary could harm some important populations of amphibians and reptiles on the island.
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This paper presents the results of an investigation of wind tunnel wall interference in a two-dimensional wind tunnel at high Mach numbers. The results are presented in the form of curves of lift coefficient versus the ratio of model chord to tunnel height, as functions of Mach number and angle of attack. The investigation was carried out by the authors at the Guggenheim Aeronautical Laboratory of the California Institute of Technology during the school year 1944-45.
Tests were carried out on the NACA low drag airfoil section 65,1-012 at Mach numbers from .60 to .80, and angles of attack of from 1 to 3 degrees. Models were 1", 2", 4" and 6" chord, giving values of the chord to tunnel height ration of .1 to .6. Schlieren photographs were made of shock waves where they occurred.
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Cada vez são mais comuns problemas relacionados a movimentos de massa nas encostas de clima tropical no Estado do Rio de Janeiro, especialmente na Serra do Mar, provocados por acumulados pluviométricos intensos. A ocupação humana desordenada de áreas sensÃveis a tais processos geomorfológicos, bem como as condicionantes geológicas, geomorfológicas, pedológicas e de uso e cobertura do solo são apontadas como fatores cruciais na explicação desses processos. O maior conhecimento da dinâmica pluviométrica bem como suas interações com tais aspectos fÃsicos ligados ao relevo parece ser a chave dessa maior compreensão desses fenômenos. Assim foram realizadas pesquisas relacionadas aos volumes e intensidades das chuvas na região do Alto Curso do Rio São João, bem como uma análise dos movimentos de massa identificados através de imagens de satélite e in loco, como forma de fornecer subsÃdios à melhor gestão do espaço dessas regiões montanhosa estão vulneráveis a movimentos de massa. A correlação entre os acumulados e a intensidade pluviométrica com fenômenos climáticos de escala global, como El Niño e La Niña também foi contemplada nessa pesquisa, mostrando uma relação mais alta com relação à intensidade da chuva mensal para anos de El Niño e para anos de La Niña uma reduzida ocorrência dessas intensidades pluviométricas. Os estudos revelaram que os tipos de solos e sua cobertura e uso têm uma grande influência na deflagração de movimentos de massa. Foram observados um número reduzido de movimentos de massa em áreas naturais e uma maior proporção desses movimentos em áreas utilizadas para a atividade da pecuária na região. Grande parte dos movimentos de massa ocorreram em áreas de Cambissolos (áreas mais elevadas) e Latossolos (áreas de encostas em menores altitudes). Ambos os solos são mais espessos do que os encontrados em áreas mais declivosas, apresentando maior acúmulo de materiais a serem mobilizados durante grandes acumulados pluviométricos, gerando movimentos de massa. A análise mostrou também que áreas mais chuvosas e com maior ocorrência de acumulados pluviométricos extremos, acima de 100 mm/dia e acima de 30mm/mês concentraram um número maior de movimentos de massa, como a região mais próxima da estação de Quartéis (porção leste). Por outro lado áreas bastante elevadas, com altas declividades, porém com predomÃnio de Mata Atlântica e áreas com solos menos espessos, como os Neossolos Litólicos, se mostraram com um número reduzido desses processos. Enfim esse estudo mostrou a necessidade de se gerir melhor os espaços dessas áreas sensÃveis sob o ponto de vista geomorfológico, até por que são áreas na periferia de regiões densamente habitadas e cujas demandas tendem a se tornar cada vez mais marcantes, o que pode gerar problemas locais, atingindo sua população e economia, com sérias conseqüências para o ambiente.
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Calandrinia galapagosa St. John is found only on San Cristóbal Island in the Galápagos archipelago, where it is severely threatened by feral goats. A population at Cerro Colorado is protected by an exclosure constructed for this purpose in 1993. Individuals of this population have white or pinkish white flowers with a green stem, whereas the population at La Galapaguera, has pinkish white flowers with a purple stem.
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We have extracted, digitized, and analyzed information about bowhead whales, Balaena mysticetus, contained in records of whaling cruises that were undertaken in the Bering, Chukchi, and Beaufort Seas from 1849 to 1914. Our database consists of 65,000 days of observations which provide insights into whether this bowhead stock may comprise more than one population.
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This paper reports on the cultural adaptation of Atlantic commercial fishermen to the danger of their occupation and efforts to ameliorate that danger through safety training programs. The research is directed towards measuring fishermen's patterns of subjective perceived danger and assessing the impact of safety training on these patterns of thinking. Safety training for commercial fishermen has unique problems owing to a culture that relies heavily on the trivialization or denial of the dangers associated with the work (Binkley, 1995; Poggie et al., 1995, 1996; Pollnac et al., 1995). Hence, understanding the efficacy of various approaches to safety training is important in promoting greater safety at sea, for this understanding will help create the most effective programs.
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This is the report from the South and West Cumberland Fisheries Advisory Committee meeting, which was held on the 27th June, 1977. The report contains sections on water resources development in West Cumbria which includes essential short and long term requirements for conservation of migratory fish stocks in the River Ehen. The section on fisheries activities includes salmon, sea trout and brown trout catches; restocking; fish mortalities; fisheries investigations/gravel abstractions in Rivers Annas, Calder, Esk, Newlands Beck, St. John's Beck, Trout Beck and Caldew; and general activities held in Holmwrange Hatchery. It also covers prosecutions and electrofishing carried out in Rivers Cocker, Marron, Ellen, Glenderaterra, Ehen, Calder, Irt, Esk and Annas. The Fisheries Advisory Committee was part of the Regional Water Authorities, in this case the North West Water Authority. This preceded the Environment Agency which came into existence in 1996.