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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Developing the Mutual Climatic Range method of palaeoclimatic reconstruction

Sinka, Katharine Jane January 1993 (has links)
No description available.
2

Dietary ecology of Chacma baboons (Papio Ursinus (Kerr, 1972) and Pleistocene Cercopithecoidea in Savanna environments of South Africa

Codron, Daryl Mark January 2003 (has links)
Bibliography: leaves 124-140. / This dissertation deals with the dietary ecology of savanna-dwelling chacma baboons (Papio ursinus), and a number of fossil cercopithecoids, from modern and Pleistocene environments of South Africa, respectively, using principles of stable light isotope ecology. Previous studies of baboon ecology, based largely on direct observations, have not quantified spatial and temporal dietary variability. The dietary ecology of fossil cercopithecoids is even less clear.
3

Late Pleistocene glacial fluctuations and palaeoceanography on the continental margin of north-west Britain

Knutz, Paul C. January 2000 (has links)
No description available.
4

Palaeo-ice sheet dynamics and depositional settings of the Late Devensian ice sheet in south-west Scotland

Salt, Keith Edward January 2001 (has links)
No description available.
5

Late Quaternary environmental change in Central Southern Africa with particular reference to extensions of the arid zone

Thomas, D. S. G. January 1984 (has links)
No description available.
6

Influence of climatic fluctuations in Neogene/on evolution of ecologically diverse plant genus: an example of Hippophae L. (Elaeagnaceae)

Jia, Dongrui January 2013 (has links)
The Neogene geologic processes and climatic changes had tremendous impact on evolution of biota in different regions of Northern Hemisphere (NH). The Qinghai- Tibetan Plateau (QTP) was a central part of these processes. Migrations from the QTP to other temperate regions represent one of the main biogeographic patterns for Northern Hemisphere. However, this 'out-of-QTP' hypothesis has never been tested through a phylogeographic analysis of a widely distributed species and the ages and routs of these migrations are largely not resolved. On the other hand, climate change played an important role in shaping the amount and structure of intraspecific genetic diversity, which provide the main basic substrate for any evolutionary change. Therefore, a detailed understanding of the effects of historic climate alterations on intraspecific genetic diversity can provide valuable insights into the evolutionary consequences of past climate changes and predicting the likely direction of global warming effects on sustainability of extant populations and species. In this thesis, I first studied the phylogeography of Hippophae rhamnoides to test the 'out-of-QTP' hypothesis (Chapter II). Then, I performed phylogenetic, dating and biogeographic analyses of the genus Hippophae (Chapter III). Finally, I studied the...
7

Synthesis of Quaternary Carbon Centers via Hydroformylation

Frimpong, Kwame January 2011 (has links)
Thesis advisor: Kian L. Tan / Utilization of directing groups in a general and efficient manner for highly regioselective hydroformylation of 1,1-disubstituted olefins. / Thesis (MS) — Boston College, 2011. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.
8

Vegetationshistoria de senaste 5000 åren kring Fållnäs gård, Södermanland : med tyngdpunkt på antropogena aktiviteter

Liljedahl, Hanna January 2009 (has links)
<p>The manor Fållnäs gård is situated at the northern end of the bay Fållnäsviken, c. 12 km north-west of Nynäshamn, Sweden. A 300 cm long sediment core collected in the bay has been analyzed regarding pollen stratigraphy. AMS <sup>14</sup>C dating of terrestrial macrofossils indicates that the sequence covers the last c. 5400 years.</p><p>The aim has been to study vegetational changes, especially human impact, in the surroundings of Fållnäs gård. Continuous findings of charcoal particles indicate that humans were present in the area at least from c. 3400 BC. Cattle breeding is indicated from c. 2200 BC by almost continues occurrences of <em>Plantago lanceolata</em>. The occurrences of pollen from cereals reveals that humans have been practicing cultivation continuously since the Neolithic/Bronze Age transition, c. 1700 BC, i.e. including a period of c. 1500 years barren of archaeological findings in the area.</p>
9

Paleo-oceanography of the subtropical southeastern Pacific during late Quaternary : a study of radiolaria, opal and quartz contents of deep-sea sediments

Molina-Cruz, Adolfo 28 May 1975 (has links)
Micropaleontological data have been analyzed through mathematical and statistical procedures, in order to: (1) establish the distribution pattern of radiolarian assemblages in the surface sediments, (2) establish the relationship of these assemblages with oceanographic variables, (3) determine the faunal composition down-core with respect to the faunal surface pattern, and (4) estimate water temperatures and 1OO M PO₄ within the geological past. This, together with the analysis of opal and quartz content of the sediments, has permitted the inference of the paleo-oceanography of the subtropical southeastern Pacific during the last 75,000 years. Factor analysis shows that five major radiolarian assemblages (factors), accounting for 93.6% of the variance, reflect the mixed layer circulation and its associated water masses. According to their position in the area, these factors are called: (1) the Subtropical factor, (2) the Equatorial factor, (3) the Peru (current) factor, (4) the Chile (current) factor, and (5) the Backwater factor. The subtropical factor is correlated with "warm" water temperatures, the Equatorial factor with opal production, the Peru factor with coastal upwelling, the Chile factor with "cool" water temperatures, and the Backwater factor with mixing of water masses. The distribution pattern of quartz reflects the position of the southeast trade winds which largely control the oceanographic conditions of the subtropical southeastern Pacific. The opal distribution resembles the patterns of surface primary productivity. Opal content is "high" below the Equatorial Undercurrent. However, it is "low" along the South American coast probably due to dilution by terrigenous input. Cores RC11-230 (8°48'S-110°48'W), V19-29 (3°35'S-83°56'W), and Y71-6-12 (16°26'S-77°23'W) were used in the stratigraphic study. Their stratigraphic control (correlation) is made through their δ ¹⁸O records. The changes of quartz, opal and radiolarian assemblages contents down-core are considered to be the result of shifts or changes in intensity of the atmospheric and oceanic circulation. Oceanographic changes have occurred in the subtropical southeastern Pacific during the last 75,000 years, but they are not manifested at each location in the same form. These changes have not been synchronous with changes of global ice volume; rather, during pronounced climatic changes, a sequence which is initiated by changes in the wind circulation is observed. The oxygen isotope stage 4 is characterized by mixing of water masses, "deep" thermocline and low concentration of nutrients. The lower interval of isotope stage 3 is characterized by weakened wind-driven circulation and "high" water temperatures. The middle of isotope stage 3 is a time in which wind-driven conditions become dominant in the region. Oxygen isotope stage 2 is "cool" and has strong wind-driven conditions. The shift to the present oceanographic conditions in the subtropical southeastern Pacific occurred 11,000 years ago. / Graduation date: 1976
10

Vegetationshistoria de senaste 5000 åren kring Fållnäs gård, Södermanland : med tyngdpunkt på antropogena aktiviteter

Liljedahl, Hanna January 2009 (has links)
The manor Fållnäs gård is situated at the northern end of the bay Fållnäsviken, c. 12 km north-west of Nynäshamn, Sweden. A 300 cm long sediment core collected in the bay has been analyzed regarding pollen stratigraphy. AMS 14C dating of terrestrial macrofossils indicates that the sequence covers the last c. 5400 years. The aim has been to study vegetational changes, especially human impact, in the surroundings of Fållnäs gård. Continuous findings of charcoal particles indicate that humans were present in the area at least from c. 3400 BC. Cattle breeding is indicated from c. 2200 BC by almost continues occurrences of Plantago lanceolata. The occurrences of pollen from cereals reveals that humans have been practicing cultivation continuously since the Neolithic/Bronze Age transition, c. 1700 BC, i.e. including a period of c. 1500 years barren of archaeological findings in the area.

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