989 resultados para Rev. James, William
Resumo:
William Francis Thompson (1888–1965), as a temporary employee of the British Columbia Provincial Fisheries Department, was assigned in 1914 to under-take full-time studies of the Pacific halibut, Hippoglossus stenolepis. The fishery was showing signs of depletion, so Thompson undertook the inquiry into this resource, the first intensive study on the Pacific halibut. Three years later, Thompson, working alone, had provided a basic foundation of knowledge for the subsequent management of this resource. He published seven land-mark papers on this species, and this work marked the first phase of a career in fisheries science that was to last nearly 50 years.
Resumo:
William Francis Thompson (1888–1965), an early fishery biologist, joined the California Fish and Game Commission in 1917 with a mandate to investigate the marine fisheries of the state. He initiated studies on the albacore tuna, Thunnus alalunga, and the Pacific sardine, Sardinops sagax, as well as studies on other economically important marine organisms. Thompson built up a staff of fishery scientists, many of whom later attained considerable renown in their field, and he helped develop, and then direct, the commission’s first marine fisheries laboratory. During his tenure in California, he developed a personal philosophy of research that he outlined in several publications. Thompson based his approach on the yield-based analysis of the fisheries as opposed to large-scale environmental studies. He left the state agency in 1925 to direct the newly formed International Fisheries Commission (now the International Pacific Halibut Commission). William Thompson became a major figure in fisheries research in the United States, and particularly in the Pacific Northwest and Alaska, during the first half of the 20th cent
Resumo:
William Francis Thompson (1888–1965), as a temporary employee of the British Columbia Provincial Fisheries Department, was assigned in 1914 to under-take full-time studies of the Pacific halibut, Hippoglossus stenolepis. The fishery was showing signs of depletion, so Thompson undertook the inquiry into this resource, the first intensive study on the Pacific halibut. Three years later, Thompson, working alone, had provided a basic foundation of knowledge for the subsequent management of this resource. He published seven land-mark papers on this species, and this work marked the first phase of a career in fisheries science that was to last nearly 50 years.
Resumo:
Stands of Scalesia pedunculata in the Galapagos Islands often develop as single-aged cohorts following episodes of mass death and regeneration. We updated earlier studies on a stand that had regenerated soon after the 1982–3 El Niño event. We quantified stem size distribution and dispersion pattern in a 0.56 ha plot near Los Gemelos on Santa Cruz Island. The plot was dominated (95% of basal area) by S. pedunculata. The stem size distribution showed the increased mean and variance for diameter (since 1987 and 1991) expected of an aging stand. Stems averaged smaller than in 1981, just before the last mass mortality episode. Large S. pedunculata stems were regularly dispersed while smaller stems were clumped and negatively associated with larger stems, implying that intraspecific competition may be important in structuring the stand. CDF Contribution Number 1008.
Resumo:
We mapped stems of three plant species in a 2.36 ha plot in the arid zone near the coast of eastern Santa Cruz Island, Galapagos, Ecuador, to determine factors influencing their local distribution. The three species were Opuntia echios var. echios (Cactaceae), a large cactus, Bursera graveolens (Burseraceae), a small tree that dominates dry woodland near the coast, and the shrub Scalesia crockeri (Asteraceae). In our plot, Opuntia was most abundant near the coast, while Bursera and Scalesia increased in density inland and with increased relief. Scalesia also increased in density with increases in Bursera and decreases in other woody plants and was most abundant 200–250 m from the coast. Both Opuntia and Bursera were clumped in the plot as a whole but selected stem size classes were randomly dispersed within homogeneous portions of the sample area. CDF Contribution Number 1012.
Resumo:
Esta é uma pesquisa sobre o uso de metáforas na construção de modelos por parte do físico escocês James Clerk Maxwell. O objetivo da pesquisa foi buscar compreender de que maneira o uso de metáforas e modelos é legítimo na ciência e em que medida contribui para seu sucesso. Além disso, busca compreender em que medida o uso de artifícios como modelos e analogias entre ramos distintos da ciência são impulsionadores de sucesso explicativo e preditivo da teoria do físico estudado. Explora as crenças teológicas e filosóficas do autor, que vê o mundo como unidade, permitindo a analogia entre ramos distintos da física. Seus desenvolvimentos em torno de teorias como calor, cores, óptica, magnetismo e eletricidade permitem evidenciar essa visão em todo o seu trabalho. Maxwell é considerado inaugurador de nova metodologia com o uso de modelos e metáforas. Explora o desenvolvimento da teoria das cores, da descrição matemática da estabilidade dos anéis de Saturno e o desenvolvimento da teoria dos gases como preâmbulo à discussão da teoria do eletromagnetismo. Descreve o desenvolvimento teórico do eletromagnetismo em seus diversos momentos. A construção da teoria do eletromagnetismo evidencia paulatino abandono do mecanicismo, uso intenso de modelos e metáforas temporários e ênfase na quantificação e no uso de experimentos. Discute o relacionamento de Maxwell com as discussões filosóficas, sociais e teológicas de sua época, seu engajamento em atividades práticas nesse sentido e suas influências científicas e filosóficas. Descreve e discute os textos filosóficos do cientista, em que se evidenciam sua ontologia, suas crenças teológicas e sua concepção de analogias. Discute a questão do uso de analogias em ciência e compara diversos autores que abordam o tema. A metodologia utilizada foi a de levantamento bibliográfico com análise crítica da literatura do autor e de seus comentadores, além de comentário crítico sobre os textos primários e secundários. Conclui que o sucesso científico de Maxwell deve-se à sua aposta numa unidade do mundo garantida por Deus, bem como na unidade entre o mundo e a mente humana, posturas que mostraram ser bem-sucedidas quando aplicadas à metodologia científica. Conclui também pela legitimidade e necessidade do uso de metáforas e modelos no empreendimento científico.
Resumo:
Background: The rising temperature of the world’s oceans has become a major threat to coral reefs globally as the severity and frequency of mass coral bleaching and mortality events increase. In 2005, high ocean temperatures in the tropical Atlantic and Caribbean resulted in the most severe bleaching event ever recorded in the basin. Methodology/Principal Findings: Satellite-based tools provided warnings for coral reef managers and scientists, guiding both the timing and location of researchers’ field observations as anomalously warm conditions developed and spread across the greater Caribbean region from June to October 2005. Field surveys of bleaching and mortality exceeded prior efforts in detail and extent, and provided a new standard for documenting the effects of bleaching and for testing nowcast and forecast products. Collaborators from 22 countries undertook the most comprehensive documentation of basin-scale bleaching to date and found that over 80% of corals bleached and over 40% died at many sites. The most severe bleaching coincided with waters nearest a western Atlantic warm pool that was centered off the northern end of the Lesser Antilles. Conclusions/Significance: Thermal stress during the 2005 event exceeded any observed from the Caribbean in the prior 20 years, and regionally-averaged temperatures were the warmest in over 150 years. Comparison of satellite data against field surveys demonstrated a significant predictive relationship between accumulated heat stress (measured using NOAA Coral Reef Watch’s Degree Heating Weeks) and bleaching intensity. This severe, widespread bleaching and mortality will undoubtedly have long-term consequences for reef ecosystems and suggests a troubled future for tropical marine ecosystems under a warming climate
Resumo:
A presente investigação propõe uma comparação entre a obra do romancista irlandês James Joyce produzida até 1904 e a obra Bombaim: cidade máxima, do escritor indiano Suketu Mehta no sentido de identificar semelhanças em certos procedimentos de representação tanto da cidade como da autorrepresentação, ou seja, a representação de si mesmo. É objetivo da investigação aqui desenvolvida também argumentar que tais semelhanças não são meramente fortuitas, mas que estão relacionadas à continuidade de processos históricos diretamente relacionados ao advento, propagação e manutenção do que a historiadora estadunidense Ellen Meiksins Wood chama de império do capital. Para levar a investigação a cabo, foi promovida uma pesquisa formada pelos seguintes desmembramentos que compõem os capítulos da tese: uma revisão dos conceitos de colônia, império e imperialismo, assim como da relação entre o Império Britânico e a Irlanda a primeira colônia britânica e terra natal de Joyce e a Índia a maior e mais importante colônia britânica e país onde Mehta nasceu; uma exploração do tema da cidade, que envolve sua relevância para a contemporaneidade, a emergência da cidade industrial capitalista, e as ideias do sociólogo alemão Georg Simmel acerca da configuração psicológica engendrada na e por essa conformação urbana; uma detida investigação da obra inicial de Joyce, no intuito de explorar o desenvolvimento do que chamamos de literatura dramática joyceana, seu uso nos primeiros textos ficcionais de Joyce e a relação de tal literatura com o tema da cidade; uma breve recapitulação de alguns dos eventos marcantes do século XX que acreditamos terem estreita relação com a pesquisa aqui desenvolvida: a derrocada do Império Britânico, a emergência dos EUA como nova potência imperial, a relação do movimento Modernista com o contexto imperialista do início do século e com o tema da cidade, ilustrada principalmente pela figura e obra de Joyce; uma detalhada exploração de Bombaim: cidade máxima, seus personagens e temas; finalmente, a explicitação das semelhanças e diferenças existentes entre as narrativas de Joyce e Mehta e de como tais características se relacionam com a emergência, manutenção e propagação do império do capital.
Resumo:
Demographic parameters were derived from sectioned otoliths of John’s Snapper (Lutjanus johnii) from 4 regions across 9° of latitude and 23° of longitude in northern Australia. Latitudinal variation in size and growth rates of this species greatly exceeded longitudinal variation. Populations of John’s Snapper farthest from the equator had the largest body sizes, in line with James’s rule, and the fastest growth rates, contrary to the temperature-size rule for ectotherms. A maximum age of 28.6 years, nearly 3 times previous estimates, was recorded and the largest individual was 990 mm in fork length. Females grew to a larger mean asymptotic fork length (L∞) than did males, a finding consistent with functional gonochorism. Otolith weight at age and gonad weight at length followed the same latitudinal trends seen in length at age. Length at maturity was ~72–87% of L∞ and varied by ~23% across the full latitudinal gradient, but age at first maturity was consistently in the range of 6–10 years, indicating that basic growth trajectories were similar across vastly different environments. We discuss both the need for complementary reproductive data in age-based studies and the insights gained from experiments where the concept of oxygen- and capacity-limited thermal tolerance is applied to explain the mechanistic causes of James’s rule in tropical fish species.
Resumo:
The overall goal of this assessment was to evaluate the effects of nutrient-source reductions that may be implemented in the Mississippi River Basin (MRB) to reduce the problem of low oxygen conditions (hypoxia) in the nearshore Gulf of Mexico. Such source reductions would affect the quality of surface waters—streams, rivers, and reservoirs—in the drainage basin itself, as well as nearshore Gulf waters. The task group’s work was divided into addressing the effects of nutrient-source reductions on: (1) surface waters in the MRB and (2) hypoxia in the Gulf of Mexico.
Resumo:
Coastal ecosystems and the services they provide are adversely affected by a wide variety of human activities. In particular, seagrass meadows are negatively affected by impacts accruing from the billion or more people who live within 50 km of them. Seagrass meadows provide important ecosystem services, including an estimated $1.9 trillion per year in the form of nutrient cycling; an order of magnitude enhancement of coral reef fish productivity; a habitat for thousands of fish, bird, and invertebrate species; and a major food source for endangered dugong, manatee, and green turtle. Although individual impacts from coastal development, degraded water quality, and climate change have been documented, there has been no quantitative global assessment of seagrass loss until now. Our comprehensive global assessment of 215 studies found that seagrasses have been disappearing at a rate of 110 square kilometers per year since 1980 and that 29% of the known areal extent has disappeared since seagrass areas were initially recorded in 1879. Furthermore, rates of decline have accelerated from a median of 0.9% per year before 1940 to 7% per year since 1990. Seagrass loss rates are comparable to those reported for mangroves, coral reefs, and tropical rainforests and place seagrass meadows among the most threatened ecosystems on earth.