988 resultados para eastern North America
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Shows eastern half of the United States, eastern half of Canada, and southern Greenland.
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The Late Cretaceous to Modern tectonic evolution of central and eastern California has been studied for many decades, with published work generally focusing on specific geographic areas and time periods. The resulting literature leaves the reader, whether graduate student, faculty member, or layperson, wondering what a coherently integrated tectonic evolution might look like, or if it would be at all possible to undertake such a task. This question is the common thread weaving together the four studies presented in this work. Each of the individual chapters is targeted at a specific location and time period which I have identified as a critical yet missing link in piecing together a coherent regional tectonic story. In the first chapter, we re-discover a set of major west down normal faults running along the western slope of the southern Sierra, the western Sierra fault system (WSFS). We show that one of these faults was offset by roughly a kilometer in Eocene time, and that this activity directly resulted in the incision of much of the relief present in modern Kings Canyon. The second chapter is a basement landscape and thermochronometric study of the hanging wall of the WSFS. New data from this study area provide a significant westward expansion of basement thermochronometric data from the southern Sierra Nevada batholith. Thermal modeling results of these data provide critical new constraints on the early exhumation of the Sierra Nevada batholith, and in the context of the results from Chapter I, allow us to piece together a coherent chronology of tectonic forcings and landscape evolution for the southern Sierra Nevada. In the third chapter, I present a study of the surface rupture of the 1999 Hector Mine earthquake, a dextral strike slip event on a fault in the Eastern California Shear Zone (ECSZ). New constraints on the active tectonics in ECSZ will help future studies better resolve the enigmatic mismatch between geologic slip rates and geodetically determined regional rates. Chapter IV is a magnetostratigraphic pilot study of the Paleocene Goler Formation. This study provides strong evidence that continued investigation will yield new constraints on the depositional age of the only fossil-bearing Paleocene terrestrial deposit on the west coast of North America. Each of these studies aims to provide important new data at critical missing links in the tectonic evolution of central and eastern California.
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This review describes the Australian decline in all-cause mortality, 1788-1990, and compares this with declines in Europe and North America. The period until the 1870s shows characteristic 'crisis mortality', attributable to epidemics of infectious disease. A decline in overall mortality is evident from 1880. A precipitous fall occurs in infant mortality from 1900, similar to that in European countries. Infant mortality continues downward during this century (except during the 1930s), with periods of accelerated decline during the 1940s (antibiotics) and early 1970s. Maternal mortality remains high until a precipitous fall in 1937 coinciding with the arrival of sulphonamide. Excess mortality due to the 1919 influenza epidemic is evident. Artefactual falls in mortality occur in 1930, and for men during the war of 1939-1945. Stagnation in overall mortality decline during the 1930s and 1945-1970 is evident for adult males, and during 1960-1970 for adult females. A decline in mortality is registered in both sexes from 1970, particularly in middle and older age groups, with narrowing of the sex differential. The mortality decline in Australia is broadly similar to those of the United Kingdom and several European countries, although an Australian advantage during last century and the first part of this century may have been due to less industrialisation, lower population density and better nutrition. Australia shows no war-related interruptions in the mortality decline. Australian mortality patterns from 1970 are also similar to those observed in North America and European countries (including the United Kingdom, but excluding Eastern Europe).
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Breeding methodologies for cultivated lucerne (Medicago sativa L.), an autotetraploid, have changed little over the last 50 years, with reliance on polycross methods and recurrent phenotypic selection. There has been, however, an increase in our understanding of lucerne biology, in particular the genetic relationships between members of the M. sativa complex, as deduced by DNA analysis. Also, the differences in breeding behaviour and vigour of diploids versus autotetraploids, and the underlying genetic causes, are discussed in relation to lucerne improvement. Medicago falcata, a member of the M. sativa complex, has contributed substantially to lucerne improvement in North America, and its diverse genetics would appear to have been under-utilised in Australian programs over the last two decades, despite the reduced need for tolerance to freezing injury in Australian environments. Breeding of lucerne in Australia only commenced on a large scale in 1977, driven by an urgent need to introgress aphid resistance into adapted backgrounds. The release in the early 1980s of lucernes with multiple pest and disease resistance (aphids, Phytophthora, Colletotrichum) had a significant effect on increasing lucerne productivity and persistence in eastern Australia, with yield increases under high disease pressure of up to 300% being recorded over the predominant Australian cultivar, up to 1977, Hunter River. Since that period, irrigated lucerne yields have plateaued, highlighting the need to identify breeding objectives, technologies, and the germplasm that will create new opportunities for increasing performance. This review discusses major goals for lucerne improvement programs in Australia, and provides indications of the germplasm sources and technologies that are likely to deliver the desired outcomes.
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Copyright: © 2014 Rodrigues et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia Civil - Área de especialização de Hidráulica
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Naturwissenschaften 94,367–374
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Proceedings of the 1" R.C.A.N.S. Congress, Lisboa, October 1992
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v.1 1818
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v.2 1818
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v.1
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v.2
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v. 1, pt. 1 (1945)
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v. 2, pt. 1 (1937)
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v. 3, pt. 1 (1910)