898 resultados para Williams, James Hunter, 1926-


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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

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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.

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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.

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In July 2007, a mandatory Federal observer program was implemented to characterize the U.S. Gulf of Mexico penaeid shrimp (Farfantepenaeus aztecus, F. duorarum, and Litopenaeus setiferus) fishery. In June 2008, the program expanded to include the South Atlantic penaeid and rock shrimp, Sicyonia spp., fisheries. Data collected from 10,206 tows during 5,197 sea days of observations were analyzed by geographical area and target species. The majority of tows (~70%) sampled were off the coasts of Texas and Louisiana. Based on total hours towed, the highest concentrated effort occurred off South Texas and southwestern Florida. Gear information, such as net characteristics, bycatch reduction devices, and turtle excluder devices were fairly consistent among areas and target species. By species categories, finfish comprised the majority (≥57%) of the catch composition in the Gulf of Mexico and South Atlantic penaeid shrimp fisheries, while in the South Atlantic rock shrimp fishery the largest component (41%) was rock shrimp. Bycatch to shrimp ratios were lower than reported in previous studies for the Gulf of Mexico penaeid shrimp fishery. These decreased ratios may be attributed to several factors, notably decreased shrimp effort and higher shrimp catch per unit of effort (CPUE) in recent years. CPUE density surface plots for several species of interest illustrated spatial differences in distribution. Hot Spot Analyses for shrimp (penaeid and rock) and bycatch species identified areas with significant clustering of high or low CPUE values. Spatial and temporal distribution of protected species interactions were documented.

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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.

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Following a tunnel excavation in low-permeability soil, it is commonly observed that the ground surface continues to settle and ground loading on the tunnel lining changes, as the pore pressures in the ground approach a new equilibrium condition. The monitored ground response following the tunnelling under St James's Park, London, shows that the mechanism of subsurface deformation is composed of three different zones: swelling, consolidation and rigid body movement. The swelling took place in a confined zone above the tunnel crown, extending vertically to approximately 5 m above it. On the sides of the tunnel, the consolidation of the soil occurred in the zone primarily within the tunnel horizon, from the shoulder to just beneath the invert, and extending laterally to a large offset from the tunnel centreline. Above these swelling and consolidation zones the soil moved downward as a rigid body. In this study, soil-fluid coupled three-dimensional finite element analyses were performed to simulate the mechanism of long-term ground response monitored at St James's Park. An advanced critical state soil model, which can simulate the behaviour of London Clay in both drained and undrained conditions, was adopted for the analyses. The analysis results are discussed and compared with the field monitoring data. It is found that the observed mechanism of long-term subsurface ground and tunnel lining response at St James's Park can be simulated accurately only when stiffness anisotropy, the variation of permeability between different units within the London Clay and non-uniform drainage conditions for the tunnel lining are considered. This has important implications for future prediction of the long-term behaviour of tunnels in clays.

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Manu National Park of southern Peru is one of the most renowned protected areas in the world, yet large-bodied vertebrate surveys conducted to date have been restricted to Cocha Cashu Biological Station, a research station covering <0.06 percent of the 1.7Mha park. Manu Park is occupied by >460 settled Matsigenka Amerindians, 300-400 isolated Matsigenka, and several, little-known groups of isolated hunter-gatherers, yet the impact of these native Amazonians on game vertebrate populations within the park remains poorly understood. On the basis of 1495 km of standardized line-transect censuses, we present density and biomass estimates for 23 mammal, bird, and reptile species for seven lowland and upland forest sites in Manu Park, including Cocha Cashu. We compare these estimates between hunted and nonhunted sites within Manu Park, and with other Neotropical forest sites. Manu Park safeguards some of the most species-rich and highest biomass assemblages of arboreal and terrestrial mammals ever recorded in Neotropical forests, most likely because of its direct Andean influence and high levels of soil fertility. Relative to Barro Colorado Island, seed predators and arboreal folivores in Manu are rare, and generalist frugivores specializing on mature fruit pulp are abundant. The impact of such a qualitative shift in the vertebrate community on the dynamics of plant regeneration, and therefore, on our understanding of tropical plant ecology, must be profound. Despite a number of external threats, Manu Park continues to serve as a baseline against which other Neotropical forests can be gauged.

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The twin-tunnel construction of the Jubilee Line Extension tunnels beneath St James's Park was simulated using coupled-consolidation finite-element analyses. The effect of defining different permeabilities for the final consolidation stage was investigated, and the performance of a fissure softening model was also evaluated. The analyses suggested an unexpectedly high permeability anisotropy for soil around the tunnel crown, possibly due to stress-induced permeability changes, or low-permeability laminations. Also, the permeability profile and lining conductivity were found to differ between the tunnels. Inclusion of the fissure model gave a narrower settlement trough, more alike that in the field, by preferentially softening simple shear behaviour. Long-term settlements at the site continue to increase at an unexpectedly high rate, suggesting the possibility of creep or unexpected soil softening during excavation. © 2012 Taylor & Francis Group.

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Seagrasses, marine flowering plants, have a long evolutionary history but are now challenged with rapid environmental changes as a result of coastal human population pressures. Seagrasses provide key ecological services, including organic carbon production and export, nutrient cycling, sediment stabilization, enhanced biodiversity, and trophic transfers to adjacent habitats in tropical and temperate regions. They also serve as “coastal canaries,” global biological sentinels of increasing anthropogenic influences in coastal ecosystems, with large-scale losses reported worldwide. Multiple stressors, including sediment and nutrient runoff, physical disturbance, invasive species, disease, commercial fishing practices, aquaculture, overgrazing, algal blooms, and global warming, cause seagrass declines at scales of square meters to hundreds of square kilometers. Reported seagrass losses have led to increased awareness of the need for seagrass protection, monitoring, management, and restoration. However, seagrass science, which has rapidly grown, is disconnected from public awareness of seagrasses, which has lagged behind awareness of other coastal ecosystems. There is a critical need for a targeted global conservation effort that includes a reduction of watershed nutrient and sediment inputs to seagrass habitats and a targeted educational program informing regulators and the public of the value of seagrass meadows.

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Objective: To develop sedation, pain, and agitation quality measures using process control methodology and evaluate their properties in clinical practice. Design: A Sedation Quality Assessment Tool was developed and validated to capture data for 12-hour periods of nursing care. Domains included pain/discomfort and sedation-agitation behaviors; sedative, analgesic, and neuromuscular blocking drug administration; ventilation status; and conditions potentially justifying deep sedation. Predefined sedation-related adverse events were recorded daily. Using an iterative process, algorithms were developed to describe the proportion of care periods with poor limb relaxation, poor ventilator synchronization, unnecessary deep sedation, agitation, and an overall optimum sedation metric. Proportion charts described processes over time (2 monthly intervals) for each ICU. The numbers of patients treated between sedation-related adverse events were described with G charts. Automated algorithms generated charts for 12 months of sequential data. Mean values for each process were calculated, and variation within and between ICUs explored qualitatively. Setting: Eight Scottish ICUs over a 12-month period. Patients: Mechanically ventilated patients. Interventions: None. Measurements and Main Results: The Sedation Quality Assessment Tool agitation-sedation domains correlated with the Richmond Sedation Agitation Scale score (Spearman [rho] = 0.75) and were reliable in clinician-clinician (weighted kappa; [kappa] = 0.66) and clinician-researcher ([kappa] = 0.82) comparisons. The limb movement domain had fair correlation with Behavioral Pain Scale ([rho] = 0.24) and was reliable in clinician-clinician ([kappa] = 0.58) and clinician-researcher ([kappa] = 0.45) comparisons. Ventilator synchronization correlated with Behavioral Pain Scale ([rho] = 0.54), and reliability in clinician-clinician ([kappa] = 0.29) and clinician-researcher ([kappa] = 0.42) comparisons was fair-moderate. Eight hundred twenty-five patients were enrolled (range, 59-235 across ICUs), providing 12,385 care periods for evaluation (range 655-3,481 across ICUs). The mean proportion of care periods with each quality metric varied between ICUs: excessive sedation 12-38%; agitation 4-17%; poor relaxation 13-21%; poor ventilator synchronization 8-17%; and overall optimum sedation 45-70%. Mean adverse event intervals ranged from 1.5 to 10.3 patients treated. The quality measures appeared relatively stable during the observation period. Conclusions: Process control methodology can be used to simultaneously monitor multiple aspects of pain-sedation-agitation management within ICUs. Variation within and between ICUs could be used as triggers to explore practice variation, improve quality, and monitor this over time

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T. G. Williams, J.J. Rowland, Lee M.H. and M.J. Neal Teaching by Example in Food Assembly by Robot, Proc. 2000 IEEE Int. Conf. On Robotics and Automation, San Francisco, April 2000, pp3247-52.