• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 373
  • 227
  • 84
  • 23
  • 21
  • 21
  • 12
  • 12
  • 12
  • 12
  • 12
  • 12
  • 7
  • 7
  • 5
  • Tagged with
  • 976
  • 262
  • 137
  • 68
  • 66
  • 62
  • 59
  • 59
  • 56
  • 55
  • 53
  • 50
  • 49
  • 48
  • 46
  • 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.
311

The Painter's Wife and Other Stories

Nadon, Candace 05 April 2013 (has links)
The Painter’s Wife and Other Stories is a novella and a collection of short fiction focusing on the lives of women and men in the contemporary Western United States. In their exploration of Western life, the novella and short stories subvert the popular mythology of the West. The novella and stories are set in one of three Colorado settings: the city of Denver, the rural Western slope, and the mountain communities of the Western Slope. Beyond being linked by region, the stories are also loosely linked by characters. Characters from one story are mentioned or make brief appearances in others, reinforcing the idea of a people connected by community and landscape.
312

En geokemisk kartering över området kring Nasa silvergruva : Effekterna av historisk gruvdrift i svensk fjällmiljö

Fahlman, Johan January 2012 (has links)
The aim of the study was to map the extent of Fe, Cu, Pb, As, Zn and S contamination in the area surrounding the Nasa silver mine. The mine operated between 1635 and 1810 with some prospecting performed in 1889, and has become infamous for the gruesome ways that the indigenous people were treated during the early years of operation. This study tested three hypotheses through a geochemical survey: 1) sulfide oxidation is still active in the abandoned mine, 2) the soil downslope of the mine is contaminated by mine drainage, and 3) the stream downslope of the mine is affected in the same way. All three hypotheses were valid, as the results showed that still, >200 years after mining operations ceased, signs of the historical mining are clearly visible in the surrounding environment. Acidic conditions were discovered in surface waters close to the waste rock piles, which indicates active sulfide oxidation. In addition, elevated levels of Fe, Cu, Pb, As, Zn and S were found in both soil and stream sediment downslope of the mines, as compared to reference localities upstream the mine (p <0.05). These results suggest that previous assessments of the mine being no threat to the environment may not be entirely correct. This study illustrates how mining waste can continue to affect the local, sub-arctic environment long after mining operations have ceased.
313

Impact of slash loading on soil temperatures and aspen regeneration

Lieffers-Pritchard, Sarah Marie 11 April 2005 (has links)
Natural regeneration is used to restock trembling aspen (Populus tremuloides Michx.) cutblocks and factors controlling regeneration are areas of interest and concern to the forest industry. Harvest operations in Manitoba require that coarse woody debris, or slash, be left and distributed in cutblocks. The objective of this study was to investigate the effects of slash loading on soil temperatures and aspen regeneration, and implications for harvest operations in the Duck Mountain area. Early sucker growth, initiation, and soil temperatures were surveyed in six winter and six summer cutblocks under different levels of slash loadings. A growth chamber study, using field temperature data as a guideline, examined the effects of diurnal temperature variation on sucker initiation and production. In winter and summer cutblocks, mean depths to sucker initiation from the parent root were 4.6 + 2.4 cm and 3.4 + 2.1 cm, respectively, and initiation of suckers occurred mainly from parental roots located in the LFH layer. Daily mean soil temperatures during the growing season were significantly lower under higher levels of slash (difference of 3.6 oC during May). Higher amounts of slash also significantly shortened the length of the growing season (89 fewer days above 0 oC in one season) and decreased the number of suckers produced (150 000 ha1 decreased to 14 000 ha-1), sucker volume (decreased by 256 cm3m-2) and leaf area index (decreased by 0.9). There was no difference in sucker production between any diurnal temperature treatments in the growth chamber study. Shallow depth to sucker initiation has important implications for harvest operations using heavy machinery especially those occurring during the summer season. Moderate levels of slash in summer cutblocks, and heavy levels of slash in winter cutblocks limit sucker growth. Although slash decreases diurnal temperature amplitudes, this may not be the reason for the decrease in sucker production associated with increased levels of slash. Both soil temperature and early sucker growth are strongly affected by slash loading; by monitoring harvest operations and the distribution of slash within cutblocks, the negative effect of heavy machine traffic and heavy piles of slash can be reduced and ensure successful forest regeneration.
314

Hydrological response unit-based blowing snow modelling over mountainous terrain

MacDonald, Matthew Kenneth 25 January 2011 (has links)
Wind transport and sublimation of snow particles are common phenomena across high altitude and latitude cold regions and play important roles in hydrological and atmospheric water and energy budgets. In spite of this, blowing snow processes have not been incorporated in many mesoscale hydrological models and land surface schemes. A physically based blowing snow model, the Prairie Blowing Snow Model (PBSM), initially developed for prairie environments was used to model snow redistribution and sublimation by wind over two sites representative of mountainous regions in Canada: Fisera Ridge in the Rocky Mountain Front Ranges in Alberta, and Granger Basin in the Yukon Territory. Two models were used to run PBSM: the object-oriented hydrological model, Cold Regions Hydrological Modelling Platform (CRHM) and Environment Canadas hydrological-land surface scheme, Modélisation Environmentale Communautaire Surface and Hydrology (MESH). PBSM was coupled with the snowcover energy and mass-balance model (SNOBAL) within CRHM. Blowing snow algorithms were also incorporated into MESH to create MESH-PBSM. CRHM, MESH and MESH-PBSM were used to simulate the evolution of snowcover in hydrological response units (HRUs) over both Fisera Ridge and Granger Basin.<p> To test the models of blowing snow redistribution and ablation over a relatively simple sequence of mountain topography, simulations were run from north to south over a linear ridge in the Canadian Rocky Mountains. Fisera Ridge snowcover simulations with CRHM were performed over two winters using two sets of wind speed forcing: (1) station observed wind speed, and (2) modelled wind speed from a widely applied empirical, terrain-based windflow model. Best results were obtained when using the site meteorological station wind speed data. The windflow model performed poorly when comparing the magnitude of modelled and observed wind speeds. Blowing snow sublimation, snowmelt and snowpack sublimation quantities were considerably overestimated when using the modelled wind speeds. As a result, end-of-winter snow accumulation was considerably underestimated on windswept HRUs. MESH and MESH-PBSM were also used to simulate snow accumulation and redistribution over these same HRUs. MESH-PBSM adequately simulated snow accumulation in the HRUs up until the spring snowmelt period. MESH without PBSM performed less well and overestimated accumulation on windward slopes and the ridge top whilst underestimating accumulation on lee slopes. Simulations in spring were degraded by a large overestimation of melt by MESH. The early and overestimated melt warrants a detailed examination that is outside the scope of this thesis.<p> To parameterize snow redistribution in a mountain alpine basin, snow redistribution and sublimation by wind were calculated for three winters over Granger Basin using CRHM. Snow transport fluxes were distributed amongst HRUs using inter-HRU snow redistribution allocation factors. Three snow redistribution schemes of varying complexity were evaluated. CRHM model results showed that end-of-winter snow accumulation can be most accurately simulated when the inter-HRU snow redistribution schemes take into account wind direction and speed and HRU aerodynamic characteristics, along with the spatial arrangement of HRUs in the catchment. As snow transport scales approximately with the fourth power of wind speed (u4), inter-HRU snow redistribution allocation factors can be established according to the predominant u4 direction over a simulation period or can change at each time step according to an input measured wind direction. MESH and MESH-PBSM were used to simulate snow accumulation and ablation over these same HRUs. MESH-PBSM provided markedly better results than MESH without blowing snow algorithms.<p> That snow redistribution by wind can be adequately simulated in computationally efficient HRUs over mountainous terrain has important implications for representing snow transport in large-scale hydrology models and land surface schemes. Snow redistribution by wind caused mountain snow accumulation to vary from 10% to 161% of seasonal snowfall within a headwater catchment in the Canadian Rocky Mountains, and blowing snow sublimation losses ranged from 10 to 37% of seasonal snowfall.
315

北部九州の樫原湿原におけるボーリング・コア試料 (KS0412-3)の分析結果(速報)(タンデトロン加速器質量分析計業績報告2004(平成16)年度)

奥野, 充, OKUNO, Mitsuru, 中村, 俊夫, NAKAMURA, Toshio, 藤木, 利之, FUJIKI, Toshiyuki, 杉山, 真二, SUGIYAMA, Shinji, 酒井, 英男, SAKAI, Hideo, 吉田, 直人, YOSHIDA, Naoto, 森, 勇一, MORI, Yuichi, 上田, 恭子, UEDA, Kyoko, 此松, 昌彦, KONOMATSU, Masahiko, 鮎沢, 潤, AIZAWA, Jun, 長岡, 信治, NAGAOKA, Shinji, 稲永, 康平, INENAGA, Kohei 03 1900 (has links)
タンデトロン加速器質量分析計業績報告 Summaries of Researches Using AMS 2004 (平成16)年度
316

Ozone monitoring and canopy effect in the Great Smoky Mountains National Park

Maloney, Ryan, January 2003 (has links) (PDF)
Thesis (M.S.)--University of Tennessee, Knoxville, 2003. / Title from title page screen (viewed Sept. 17, 2003). Thesis advisor: Wayne T. Davis. Document formatted into pages (x, 102 p. : ill., maps, charts). Vita. Includes bibliographical references (p. 39-40).
317

Temporal and spatial evolution of the Cave Graben Fault System, Guadalupe Mountains, New Mexico

Mathisen, Maren Gabriella 09 March 2015 (has links)
Numerous recent studies have demonstrated the importance of syndepositional faulting as an inherent element of steep-rimmed carbonate margins. However, these studies have not emphasized the relationship to older shelf margins, multiphase deformation history, and complexity of fault zone internal structure. In the Guadalupe Mountains, New Mexico, extensive syndepositional deformation parallels the Permian Capitan shelf margin reef and has developed in the absence of regional tectonic forces due to a combination of early carbonate cementation, gravitational instability, differential compaction, and variable progradation to aggradation at pre-existing shelf margins. This study focuses on the geometry, growth history, and internal fill type distribution within the Cave Graben Fault System (CGFS) in Slaughter and Rattlesnake Canyons of the Guadalupian (Capitan) shelf margin with the intent to understand the temporal and spatial evolution of deformation in front of the G24 shelf margin. Stratigraphy, faults and fractures exposed within the CGFS were mapped using high-resolution gigapan photos and GPS, along with RCRL Guadalupe airborne lidar, provides a geospatial database for 3D visualization, quantification, and interpretation. Detailed mapping reveals a high degree of variability in fault geometry, including the presence of vertical and lateral fault relays, antithetic and synthetic splays, and highly variable fault and fracture apertures, suggesting a complex deformational history. Hundreds of early-formed fractures have been mapped within the G24-G25 shelf margin system, but the development of significant faults with appreciable displacement only occurs in front of the G24 margin. Vertical fault displacement varies from 9 to 34 m in the CGFS. Breccias several meters in width fill the main faults and contain entrained sediment and clasts of variable age and composition. Stratal geometries reveal that movement and episodic growth occurred along the faults soon after deposition. Further investigation of the sediment and breccia fills suggests that a significant dissolution event along the fault allowed for the entrainment of much younger, post-Permian sediment. Based on these findings it appears that in Rattlesnake Canyon at least 30-60% of the CGFS vertical displacement occurs in the Permian, whereas up to 40-70% may develop post-Permian, providing a significant advancement in the understanding of timing of fault systems within the Capitan shelf margin. / text
318

The Effects of Mountains On the Quality of the Atmosphere

Douglass, A.E. January 1899 (has links)
No description available.
319

The tectonic geomorphology of the northern Sangre de Cristo Mountains, near Villa Grove, Colorado

Peterson, Robert Howard January 1979 (has links)
No description available.
320

Group organization and activity patterns of desert bighorn sheep

Chilelli, MaryEllen January 1981 (has links)
No description available.

Page generated in 0.047 seconds