• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 706
  • 62
  • 53
  • 31
  • 15
  • 14
  • 14
  • 14
  • 14
  • 14
  • 14
  • 7
  • 5
  • 5
  • 3
  • Tagged with
  • 1044
  • 1044
  • 267
  • 222
  • 198
  • 142
  • 128
  • 127
  • 100
  • 83
  • 78
  • 73
  • 70
  • 70
  • 67
  • 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.
131

The sensitivity of microbial respiration across nutrient gradients in peat soils to factors associated with climate change

Marshall, Rachel January 2013 (has links)
This thesis examines whether short term (one to three weeks) microbial sensitivity to temperature and carbon (C) inputs can be predicted from peat characteristics driven by nutrient gradients. The aim was to determine if relationships exist between peat macronutrient (C, nitrogen (N), phosphorus (P)) concentrations, microbial community composition and the microbial response to changes in temperature and C supply. The focus of this thesis was on using peat macronutrient concentrations as explanatory variables as this is a metric which is easy to define and measure consistently, unlike other factors such as peat C quality and availability of nutrients. It was observed that, over short timescales, microbial respiration rates in peat soils increased in response to warming, nutrient (N and P) additions and increased labile C supply. In the first two experimental chapters it was found that peat respiration was sensitive to temperature, with increases of 10°C shown to increase microbial CO2 production by factors of 2.8 to 4.4. In the final two experimental chapters priming effects in peat were examined with C additions found to stimulate microbial activity and increases in peat derived CO2 flux, which could be attributed to priming. Despite the wide variation in nutrient concentrations in the peat soils examined no clear relationships between peat nutrient properties (total and available concentrations) and the magnitude of the microbial responses were observed.
132

Climate change as a controlling parameter in sediment supply : the Nile Province

Palacios, Zonia H. January 2013 (has links)
This project studies the relation between the amount of sediment deposited in the Nile Submarine Cone (NSC) and the influence exerted by external controls such as climate change. A detailed calculation of sediment volumes was performed as well as a detailed estimation between intervals in order to assess sedimentation rates and dry mass per Ma for the NSC from the Late Oligocene to Recent. In contrast to previous studies, this project presents for the first time detailed calculations for ten intervals from Late Oligocene to Re- cent, including calculations for Pre-Messinian deposits since they also play an important role in the evolution of the NSC and in the history of erosion and deposition processes in the Nile province. The results of this project evidenced a connection between climate change and the amount of sediment carried by rivers as well as its final fate. Sedimenta- tion rate values obtained for each interval showed an increase in sediment supply during the Late Pliocene-Early Pleistocene, coincident with the i) final uplift of the Ethiopian and Somalian plateaus, ii) the drop in temperatures that took in the northern hemisphere as a consequence of the growth of the ice sheets, and iii) the increase in rainfall in the Ethiopian Highlands as a consequence of the African and Indian Monsoon that produced sapropel deposits and eroded sediments in north-eastern Africa. Pre-Messinian intervals showed low sedimentation rates values compared to Post-Messinian associated probably with an elevated evapo-transpiration cycle reducing the rainfall in the Ethiopian Highlands, des- pite the humid conditions that were present during certain ages (e.g. Zeit Wet Phase Late Miocene).
133

Securitising of climate change / Securitising climate change

Wilner, Nathanael 17 October 2011 (has links)
Unchecked climate change has the potential to have devastating effect on the Earth and its inhabitants. However, there is still time to avoid most of the worst impacts climate change will bring through massive mitigative actions. While state led governance mechanisms must be employed to effectively mitigate climate change, states seem unwilling or unable to effectuate the needed actions. How can states be pushed to take action aimed at mitigating climate change? This thesis utilises Securitisation Theory, as a starting point to test not only whether or not securitising climate change can induce state action on it, but also whether induced policies constitute ‘good’ or ‘bad’ actions. This thesis undertakes two case studies that focus on the executive level of governance of two sate: the United States and California. / Graduate
134

Paleoclimate models for western North America as inferred from speleothem isotope records /

Serefiddin, Feride. Schwarcz, H. P. January 2003 (has links)
Thesis (Ph.D.)--McMaster University, 2003. / Advisor: H. P. Schwarcz. Includes bibliographical references. Also available via World Wide Web.
135

Paleoclimate models for western North America as inferred from speleothem isotope records /

Serefiddin, Feride. Schwarcz, H. P. January 2003 (has links)
Thesis (Ph.D.)--McMaster University, 2003. / Advisor: H. P. Schwarcz. Includes bibliographical references. Also available via World Wide Web.
136

Climatic change and Chinese population growth dynamics over the last millennium

Lee, Fung, January 2007 (has links)
Thesis (Ph. D.)--University of Hong Kong, 2008. / Also available in print.
137

The impact of climate change on benthic-pelagic coupling and the biogeochemical cycling of Narragansett Bay, R.I./

Fulweiler, Robinson Walter. January 2007 (has links)
Thesis (Ph.D.)--University of Rhode Island, 2007. / Includes bibliographical references (leaves 233-250).
138

Climatic variations in tropical West African rainfall and the implications for military planners

Montgomery, Christi S. January 2008 (has links) (PDF)
Thesis (M.S. in Meteorology and Physical Oceanography)--Naval Postgraduate School, June 2008. / Thesis Advisor(s): Murphree,Tom. "June 2008." Description based on title screen as viewed on August 26, 2008. Includes bibliographical references (p.83-87). Also available in print.
139

Statistical modeling of daily streamflow processes in consideration of climate change

Villemain, Stéphane. January 1900 (has links)
Thesis (M.Eng.). / Written for the Dept. of Civil Engineering and Applied Mechanics. Title from title page of PDF (viewed 2008/07/29). Includes bibliographical references.
140

Storm track variability and interaction with the background flow on daily, interannual and climate change time scales /

Wettstein, Justin J. January 2007 (has links)
Thesis (Ph. D.)--University of Washington, 2007. / Vita. Includes bibliographical references (p. 103-107).

Page generated in 0.205 seconds