919 resultados para North American Datum 1927
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This paper presents the results of a multivariate spatial analysis of 38 vowel formant variables in the language of 402 informants from 236 cities from across the contiguous United States, based on the acoustic data from the Atlas of North American English (Labov, Ash & Boberg, 2006). The results of the analysis both confirm and challenge the results of the Atlas. Most notably, while the analysis identifies similar patterns as the Atlas in the West and the Southeast, the analysis finds that the Midwest and the Northeast are distinct dialect regions that are considerably stronger than the traditional Midland and Northern dialect region indentified in the Atlas. The analysis also finds evidence that a western vowel shift is actively shaping the language of the Western United States.
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Peatland ecosystems store about 500-600 Pg of organic carbon, largely accumulated since the last glaciation. Whether they continue to sequester carbon or release it as greenhouse gases, perhaps in large amounts, is important in Earth's temperature dynamics. Given both ages and depths of numerous dated sample peatlands, their rate of carbon sequestration can be estimated throughout the Holocene. Here we use average values for carbon content per unit volume, the geographical extent of peatlands, and ecological models of peatland establishment and growth, to reconstruct the time-trajectory of peatland carbon sequestration in North America and project it into the future. Peatlands there contain ~163 Pg of carbon. Ignoring effects of climate change and other major anthropogenic disturbances, the rate of carbon accumulation is projected to decline slowly over millennia as reduced net carbon accumulation in existing peatlands is largely balanced by new peatland establishment. Peatlands are one of few long-term terrestrial carbon sinks, probably important for global carbon regulation in future generations. This study contributes to a better understanding of these ecosystems that will assist their inclusion in earth-system models, and therefore their management to maintain carbon storage during climate change.
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The major topographic features, or provinces, beyond the continental slope off the Atlantic coast of the United States are (1) Sohm Plain, (2) Hatteras Plain, (3) Nares Plain, (4) Blake Basin, (5) Blake Plateau-Bahama Banks, and (6) Bermuda Rise. The whole of the described area is commonly referred to as the North American Basin. This basin is bounded on the north by Newfoundland Ridge and on the south by Puerto Rico Trench. Topographic features of note within the basin are the divide and the area of depressions between Sohm and Hatteras Plains, the sharply crested Blake Ridge, and the Puerto Rico Ridge. Recently accumulated data on deep-sea oores has given good evidence that the silt and sand covering the abyssal plains are displaced continental sediments in a virtually quartz-free oceanic environment. These sediments were deposited on a primary volcanic bottom. The primary or volcanic bottom is characterized by abyssal hills and seamounts, and the sediment bottom is characterized by abyssal plains, which extend seaward from the continental margins. On the Blake Plateau, bottom photographs and dredge hauls in the axis of the stream show that locally sediment has been removed and the bottom is paved with crusts and nodules of manganese. Photographs and dredged samples from the outer part of the New England Seamount, Chain and Caryn Peak also indicate extensive encrustations of manganese oxide which acts as a binding agent in areas of ooze or other organic debris and thus helps to stabilize the bottom.
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Richard Hooker and John Locke were important sources for the thought and public lives of Anglican leaders in the North American colonies. A conviction about religious freedom of conscience during the first half of the eighteenth century constitutes a range of thinking about toleration that contributed to the birth of the republic.
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Yield management helps hotels more profitably manage the capacity of their rooms. Hotels tend to have two types of business: transient and group. Yield management research and systems have been designed for transient business in which the group forecast is taken as a given. In this research, forecast data from approximately 90 hotels of a large North American hotel chain were used to determine the accuracy of group forecasts and to identify factors associated with accurate forecasts. Forecasts showed a positive bias and had a mean absolute percentage error (MAPE) of 40% at two months before arrival; 30% at one month before arrival; and 10-15% on the day of arrival. Larger hotels, hotels with a higher dependence on group business, and hotels that updated their forecasts frequently during the month before arrival had more accurate forecasts.
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Análisis de las dependencias y novedades que, respecto al argumento de la Eneida de Virgilio, ofrece la reciente novela Lavinia (2009), de la escritora norteamericana Úrsula K. Le Guin.
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Over the past several decades, thousands of otoliths, bivalve shells, and scales have been collected for the purposes of age determination and remain archived in European and North American fisheries laboratories. Advances in digital imaging and computer software combined with techniques developed by tree-ring scientists provide a means by which to extract additional levels of information in these calcified structures and generate annually resolved (one value per year), multidecadal time-series of population-level growth anomalies. Chemical and isotopic properties may also be extracted to provide additional information regarding the environmental conditions these organisms experienced.Given that they are exactly placed in time, chronologies can be directly compared to instrumental climate records, chronologies from other regions or species, or time-seriesof other biological phenomena. In this way, chronologies may be used to reconstruct historical ranges of environmental variability, identify climatic drivers of growth, establish linkages within and among species, and generate ecosystem-level indicators. Following the first workshop in Hamburg, Germany, in December 2014, the second workshop on Growth increment Chronologies in Marine Fish: climate-ecosystem interactions in the North Atlantic (WKGIC2) met at the Mediterranean Institute for Advanced Studies headquarters in Esporles, Spain, on 18–22 April 2016, chaired by Bryan Black (USA) and Christoph Stransky (Germany).Thirty-six participants from fifteen different countries attended. Objectives were to i) review the applications of chronologies developed from growth-increment widths in the hard parts (otoliths, shells, scales) of marine fish and bivalve species ii) review the fundamentals of crossdating and chronology development, iii) discuss assumptions and limitations of these approaches, iv) measure otolith growth-increment widths in image analysis software, v) learn software to statistically check increment dating accuracy, vi) generate a growth increment chronology and relate it to climate indices, and vii) initiate cooperative projects or training exercises to commence after the workshop.The workshop began with an overview of tree-ring techniques of chronology development, including a hands-on exercise in cross dating. Next, we discussed the applications of fish and bivalve biochronologies and the range of issues that could be addressed. We then reviewed key assumptions and limitations, especially those associated with short-lived species for which there are numerous and extensive otolith archives in European fisheries labs. Next, participants were provided with images of European plaice otoliths from the North Sea and taught to measure increment widths in image analysis software. Upon completion of measurements, techniques of chronology development were discussed and contrasted to those that have been applied for long-lived species. Plaice growth time-series were then related to environmental variability using the KNMI Climate Explorer. Finally, potential future collaborations and funding opportunities were discussed, and there was a clear desire to meet again to compare various statistical techniques for chronology development using a range existing fish, bivalve, and tree growth-increment datasets. Overall, we hope to increase the use of these techniques, and over the long term, develop networks of biochronologies for integrative analyses of ecosystem functioning and relationships to long-term climate variability and fishing pressure.
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Carbon Monoxide (CO) and Ozone (O3) are considered to be one of the most important atmospheric pollutants in the troposphere with both having significant effects on human health. Both are included in the U.S. E.P.A list of criteria pollutants. CO is primarily emitted in the source region whereas O3 can be formed near the source, during transport of the pollution plumes containing O3 precursors or in a receptor region as the plumes subside. The long chemical lifetimes of both CO and O3 enable them to be transported over long distances. This transport is important on continental scales as well, commonly referred to as inter-continental transport and affects the concentrations of both CO and O3 in downwind receptor regions, thereby having significant implications for their air quality standards. Over the period 2001-2011, there have been decreases in the anthropogenic emissions of CO and NOx in North America and Europe whereas the emissions over Asia have increased. How these emission trends have affected concentrations at remote sites located downwind of these continents is an important question. The PICO-NARE observatory located on the Pico Mountain in Azores, Portugal is frequently impacted by North American pollution outflow (both anthropogenic and biomass burning) and is a unique site to investigate long range transport from North America. This study uses in-situ observations of CO and O3 for the period 2001-2011 at PICO-NARE coupled with output from the full chemistry (with normal and fixed anthropogenic emissions) and tagged CO simulations in GEOS-Chem, a global 3-D chemical transport model of atmospheric composition driven by meteorological input from the Goddard Earth Observing System (GEOS) of the NASA Global Modeling and Assimilation Office, to determine and interpret the trends in CO and O3 concentrations over the past decade. These trends would be useful in ascertaining the impacts emission reductions in the United States have had over Pico and in general over the North Atlantic. A regression model with sinusoidal functions and a linear trend term was fit to the in-situ observations and the GEOS-Chem output for CO and O3 at Pico respectively. The regression model yielded decreasing trends for CO and O3 with the observations (-0.314 ppbv/year & -0.208 ppbv/year respectively) and the full chemistry simulation with normal emissions (-0.343 ppbv/year & -0.526 ppbv/year respectively). Based on analysis of the results from the full chemistry simulation with fixed anthropogenic emissions and the tagged CO simulation it was concluded that the decreasing trends in CO were a consequence of the anthropogenic emission changes in regions such as USA and Asia. The emission reductions in USA are countered by Asian increases but the former have a greater impact resulting in decreasing trends for CO at PICO-NARE. For O3 however, it is the increase in water vapor content (which increases O3 destruction) along the pathways of transport from North America to PICO-NARE as well as around the site that has resulted in decreasing trends over this period. This decrease is offset by increase in O3 concentrations due to anthropogenic influence which could be due to increasing Asian emissions of O3 precursors as these emissions have decreased over the US. However, the anthropogenic influence does not change the final direction of the trend. It can thus be concluded that CO and O3 concentrations at PICO-NARE have decreased over 2001-2011.
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Universidade Estadual de Campinas . Faculdade de Educação Física
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Universidade Estadual de Campinas . Faculdade de Educação Física
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Universidade Estadual de Campinas . Faculdade de Educação Física