860 resultados para Incised valley
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We assessed the diversity of woody plants at 15 forested sites in the Tansa Valley of Thane District, in Maharashtra, India. The fewest species (11) were seen at a degraded mangrove site near the river mouth, and the greatest number (150) in the rich semi-evergreen forest on Tungar Hill. For all sites there were 141 tree, 25 shrub and 15 liana species, a total of 181 species. Excluding the mangrove site, which had no species in common with the other 14 sites, we analyzed the species distributions in detail. 2 These sites ranged in area from 4 to 30 km each, had woody floras of 89 6 6 species, and varied in intensity of human impact. Despite a history of exploitation and substantial reduction in biomass from firewood collecting, set fires and illicit tree felling, considerable plant diversity remains in the area.We found a modest increase in species richness in transects away from two villages. We observed the exploitation of the forest by the principal users, primarily of the Warli Tribe. They exploited a wide variety of forest resources (92 species), for medicines, foods, construction materials, household goods, manure and other purposes. They collected 15 items for sale. By far the single most important item collected was firewood, which dramatically reduced forest biomass within 2 km of villages. The species distributions in these forest remnants are strongly nested, mostly due to varying degrees of disturbance at individual sites. The high species diversity on Tungar Hill is most likely a relict of the earlier character of forests throughout much of the valley. It merits the highest priorities for preservation, as a refuge for Western Ghat species at the northern limits of their distributions.
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The information presented in this article is derived from the testimony and exhibits offered in connection with the trial of Auger, et a1 v. The Stouffer Corporation, et al., Civil Action No. 93-2529, which took place in the United States District Court for the Eastern District of Pennsylvania. The authors of this article served as expert consultants and expert witnesses to the plaintiff
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A description and model of the near-surface hydrothermal system at Casa Diablo, with its implications for the larger-scale hydrothermal system of Long Valley, California, is presented. The data include resistivity profiles with penetrations to three different depth ranges, and analyses of inorganic mercury concentrations in 144 soil samples taken over a 1.3 by 1.7 km area. Analyses of the data together with the mapping of active surface hydrothermal features (fumaroles, mudpots, etc.), has revealed that the relationship between the hydrothermal system, surface hydrothermal activity, and mercury anomalies is strongly controlled by faults and topography. There are, however, more subtle factors responsible for the location of many active and anomalous zones such as fractures, zones of high permeability, and interactions between hydrothermal and cooler groundwater. In addition, the near-surface location of the upwelling from the deep hydrothermal reservoir, which supplies the geothermal power plants at Casa Diablo and the numerous hot pools in the caldera with hydrothermal water, has been detected. The data indicate that after upwelling the hydrothermal water flows eastward at shallow depth for at least 2 km and probably continues another 10 km to the east, all the way to Lake Crowley.
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In this paper, I report on the variety of English spoken in the relatively new community of Happy Valley-Goose Bay, Labrador. The efects of dialect contact and the process of dialect levelling (Trudgill 1986; Britain 1997, Kerswill and Williams 2000; Kerswill 2002) are observed by examining the development of several vowels in the Happy Valley- Goose Bay vowel system. In this community the migrant generation showed evidence of mixing. The frst generation showed the most evidence of levelling along with the emergence of new distinctions. The second generation showed some evidence of levelling, the emergence of new distinctions, and in some cases a return to patterns present in the migrant generation. These results indicate that diferent vowels within a dialect can move through the stages of dialect contact at diferent rates due to the multitude of infuences on the process of dialect contact.
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Antarctic glacier forefields are extreme environments and pioneer sites for ecological succession. Increasing temperatures due to global warming lead to enhanced deglaciation processes in cold-affected habitats, and new terrain is becoming exposed to soil formation and microbial colonization. However, only little is known about the impact of environmental changes on microbial communities and how they develop in connection to shifting habitat characteristics. In this study, using a combination of molecular and geochemical analysis, we determine the structure and development of bacterial communities depending on soil parameters in two different glacier forefields on Larsemann Hills, East Antarctica. Our results demonstrate that deglaciation-dependent habitat formation, resulting in a gradient in soil moisture, pH and conductivity, leads to an orderly bacterial succession for some groups, for example Cyanobacteria, Bacteroidetes and Deltaproteobacteria in a transect representing 'classical' glacier forefields. A variable bacterial distribution and different composed communities were revealed according to soil heterogeneity in a slightly 'matured' glacier forefield transect, where Gemmatimonadetes, Flavobacteria, Gamma- and Deltaproteobacteria occur depending on water availability and soil depth. Actinobacteria are dominant in both sites with dominance connected to certain trace elements in the glacier forefields.
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Peer reviewed
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Peer reviewed
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Peer reviewed
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Peer reviewed
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Acknowledgements This work was funded by Natural Science Foundation of China under grant numbers of 41071337 and 40830528 and jointly by the Priority Academic Program Development of Jiangsu Higher Education Institutions, China.
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Inscriptions: Verso: [stamped] Photograph by Freda Leinwand. [463 West Street, Studio 229G, New York, NY 10014].
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A Pliocene (2.6-3.5 Ma) age is determined from glacial sediments studied in a 20m long, 4 m deep trench excavated in Heidemann Valley, Vestfold Hills, East Antarctica. The age determination is based on a combined study of amino acid racemization, diatoms, foraminifera, and magnetic polarity, and supports earlier estimates of the age of the sedimentary section; all are beyond 14C range. Four till units are recognized and documented, and 16 subunits are identified. All are ascribed to deposition during a Late Pliocene glaciation that was probably the last time the entire Vestfold Hills was covered by an enlarged East Antarctic Ice Sheet (EAIS). Evidence for other more recent glacial events of the 'Vestfold Glaciation' may have been due to lateral expansion of the Sorsdal Glacier and limited expansion of the icesheet margin during the Last Glacial Maximum rather than a major expansion of the EAIS. The deposit appears to correlate with a marine deposition event recorded in Ocean Drilling Program Site 1166 in Prydz Bay, possibly with the Bardin Bluffs Formation of the Prince Charles Mountains and with part of the time represented in the ANDRILL AND-1B core in the Ross Sea.