• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 39
  • 8
  • 6
  • 4
  • 3
  • 3
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 85
  • 9
  • 8
  • 8
  • 7
  • 6
  • 6
  • 6
  • 6
  • 5
  • 5
  • 5
  • 5
  • 5
  • 5
  • 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.
31

Nesting and Habitat Parameters for Selected Raptors in the Desert of Northwestern Utah

Peterson, David L. 01 May 1988 (has links)
This study examined the effects of habitat parameters, disturbances and predation on the reproductive success of golden eagles (Aguila chrysaetos), ferruginous hawks (Buteo regalis), red-tailed hawks (Buteo jamaicensis) and prairie falcons (Falco mexicanus) in the desert area southwest of the Great Salt Lake in northwestern Utah. The prairie falcon was the only species examined that had a normal reproductive output during the study years of 1984-1986. The prairie falcon was better able to utilize the avian prey species which were very difficult for the larger and slower raptor species to capture. During the reproductive period prairie falcons used Townsend ground squirrel (Sperrnophilus townsendii) heavily. The golden eagles, ferruginous, and red-tailed hawks were not able to obtain sufficient numbers of their primary prey species, the cottontail rabbit (Sylvilagus nuttallii) and black-tailed jackrabbit (Lepus californicus), to allow for a normal reproductive output. These prey species were at the low point of their cyclic population pattern. Disturbance to raptors was not an important factor on this remote study area. Predation, primarily terrestrial mammals, did have a negative effect on reproductive success; however, it was not a major consideration due to lack of predator access on most of the cliff nesting sites of the golden eagle, red-tailed hawk, and prairie falcon. Predation appeared to have a greater impact on the ferruginous hawk nesting success as their nest sites were normally accessable to mammalian predators. Raptor nest site exposure was unimportant to nesting raptors. The nest exposure was very similar to the exposure ratio of the available cliff sites.
32

The Role of Vegetation Structure, Composition, and Nutrition in Greater Sage-Grouse Ecology in Northwestern Utah

Wing, Brian R. 01 May 2014 (has links)
The greater sage-grouse (Centrocercus urophasianus; sage-grouse) is the largest grouse species in North America and an indicator species for the condition of sagebrush (Artemisia spp.) ecosystems. The Box Elder Sage-Grouse Management Area (SGMA) in northwestern Utah encompasses one of the state’s largest sage-grouse populations. To fill knowledge gaps regarding the population inhabiting the Raft River subunit of the Box Elder SGMA, I captured, radio-marked, and monitored 123 (68 female, 55 male) sage-grouse from January 2012 through December 2013. My purpose was to describe how the seasonal movements, survival, and reproductive rates of this sage-grouse population are effected by small-scale habitat use and breeding season foraging patterns. Sage-grouse in the Raft River subunit have distinct winter and summer ranges, and some travelled long distances annually. Survival rates were similar to other Utah populations and range-wide averages. Nest and brood success rates were above range-wide averages and those reported in the adjacent Grouse Creek subunit of the same SGMA. Sage-grouse in the study area selected habitats with specific vegetation characteristics to fit their seasonal needs. Sage-grouse use sites differed from random sites with greater forb height, grass height, and shrub height and cover. Nest success rates were directly related to selected vegetation, as successful nests were located more often under sagebrush and within greater forb height and cover and grass and shrub height than unsuccessful nests. Brood sites were also greater in forb, grass, and shrub height than other use sites. In March and April of 2013, I located radio-marked sage-grouse at flock browse sites to observe their sagebrush diet selection patterns. Lab analyses showed no differences in nutritional quality or chemical composition between browsed sagebrush plants and non-browsed and random plants. However, browsed black sagebrush (A. nova) was lower in protein and higher in chemical content than browsed Wyoming big sagebrush (A. tridentata wyomingensis). Radio-marked females were frequently observed at sites where black sagebrush was browsed, and one individual chemical was considerably more concentrated in browsed plants associated with females that nested successfully. My research provides useful information regarding the seasonal habitat use patterns and vegetation preferences of sage-grouse in the Box Elder SGMA. To conserve the sage-grouse population in northwestern Utah, management actions must protect the seasonal habitats and vegetation that the species depends on for its productivity and survival.
33

An archaeological survey in the Clearwater River Provincial Park, Saskatchewan : insights into the archaeology of the boreal forest of northwestern Saskatchewan

Korejbo, Alan John 22 August 2011
An archaeological survey was conducted in the Clearwater River Valley, Saskatchewan in the summer of 2008 by University of Saskatchewan Masters student Alan Korejbo and a crew of three. Prior to this project, only three sites had been recorded along this 55 km portion of the river. Researching this remote wilderness heritage river in the boreal ecoregion presented substantial logistical barriers; nonetheless, a total of seventeen sites, mostly precontact in nature, were discovered. The density of sites identified in this survey suggests that this region is archaeologically rich; thus, meriting future research. Information collected from this encourages vigorous archaeological resource management in the Clearwater River Provincial Park. Data from this survey may give future researchers a basis from which to start. Survey results and previous research are combined to hypothesize past land usage in northwestern Saskatchewan. Furthermore, coupled with previous research, the data from this project may allow us to suggest possible cultural influence and interaction and ask pertinent questions that may aid in future research here.
34

An archaeological survey in the Clearwater River Provincial Park, Saskatchewan : insights into the archaeology of the boreal forest of northwestern Saskatchewan

Korejbo, Alan John 22 August 2011 (has links)
An archaeological survey was conducted in the Clearwater River Valley, Saskatchewan in the summer of 2008 by University of Saskatchewan Masters student Alan Korejbo and a crew of three. Prior to this project, only three sites had been recorded along this 55 km portion of the river. Researching this remote wilderness heritage river in the boreal ecoregion presented substantial logistical barriers; nonetheless, a total of seventeen sites, mostly precontact in nature, were discovered. The density of sites identified in this survey suggests that this region is archaeologically rich; thus, meriting future research. Information collected from this encourages vigorous archaeological resource management in the Clearwater River Provincial Park. Data from this survey may give future researchers a basis from which to start. Survey results and previous research are combined to hypothesize past land usage in northwestern Saskatchewan. Furthermore, coupled with previous research, the data from this project may allow us to suggest possible cultural influence and interaction and ask pertinent questions that may aid in future research here.
35

Tectono-metamorphic Evolution Of The Northern Menderes Massif: Evidence From The Horst Between Gordes And Demirci Basins (west Anatolia, Turkey)

Bugdaycioglu, Cagri 01 September 2004 (has links) (PDF)
The Menderes Massif forms a large metamorphic culmination in western Turkey &amp / #8211 / an extensional province where continental lithosphere has been stretching following Palaeogene crustal thickening. Northern sector of the Massif on the horst between G&ouml / rdes and Demirci Basins was chosen for structural analysis aimed to study the tectono-metamorphic evolution of the northern Menderes Massif. Within the study area, four groups of rocks are recognized: (1) the metamorphic rocks &amp / #8211 / orthogneisses and metasediments / (2) pegmatoids / (3) Neogene sedimentary rocks / and (4) Quaternary alluvial sediments. The tectono-metamorphic history of the region involves a regional metamorphism (M1) at upper-amphibolite-facies conditions, coeval with a top-tothe-NNE contractional D1 deformation during the northward backthrusting of Lycian Nappes (Eocene main Menderes metamorphism). Partial anatexis during the latest stages of the M1 was speculated to be the main mechanism for the formation of the migmatites and the granitic magma. Pegmatoid domes and dikes/sills formed during late increments of this phase. A second metamorphism (M2) and coeval top-to-the-NNE deformation (D2) took place during the Early Miocene exhumation of the metamorphic rocks along a presently low-angle normal fault in an extensional shear zone at presumably greenschist facies conditions during declining P-T conditions. The latest deformation phase (D3) is high-angle normal faulting due to N&amp / #8211 / S extension affecting western Anatolia. The E&amp / #8211 / W grabens dissecting the Massif into northern, central and southern submassifs are the result of this phase, commenced during Pliocene-Pleistocene and gave the western Anatolia much of its present-day shape. The evidence presented supports the idea of episodic two-stage extension in western Turkey.
36

Robert Dickson, British fur trader on the upper Mississippi

Tohill, Louis Arthur. January 1900 (has links)
Thesis--University of Minnesota, 1926. / Bibliography ; numb. 1, 106-124.
37

Robert Dickson, British fur trader on the upper Mississippi

Tohill, Louis Arthur. January 1900 (has links)
Thesis--University of Minnesota, 1926. / Bibliography ; numb. 1, 106-124.
38

Um ponto fora da linha: a formação urbana do município de Pirajuí (1900 – 1930) / A point off the line: the urban formation of Pirajuí city (1900 - 1930)

Fabri, Fernanda Aparecida 24 October 2017 (has links)
Submitted by Fernanda Aparecida Fabri null (fabri.fernanda@gmail.com) on 2017-12-19T18:36:52Z No. of bitstreams: 2 Fernanda Fabri_versão final.pdf: 5613223 bytes, checksum: 518c8d1c7033c0a51b303ae58945407c (MD5) Fernanda Fabri_versão final.pdf: 5613223 bytes, checksum: 518c8d1c7033c0a51b303ae58945407c (MD5) / Approved for entry into archive by Maria Marlene Zaniboni null (zaniboni@bauru.unesp.br) on 2017-12-20T13:23:24Z (GMT) No. of bitstreams: 1 fabri_fa_me_bauru.pdf: 5613223 bytes, checksum: 518c8d1c7033c0a51b303ae58945407c (MD5) / Made available in DSpace on 2017-12-20T13:23:24Z (GMT). No. of bitstreams: 1 fabri_fa_me_bauru.pdf: 5613223 bytes, checksum: 518c8d1c7033c0a51b303ae58945407c (MD5) Previous issue date: 2017-10-24 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O período de expansão cafeeira, compreendido entre meados do século XIX e início do século XX, foi crucial para o processo de criação de cidades em São Paulo, acompanhado simultaneamente pela ferrovia em direção as divisas do estado. Pirajuí, situada no, atualmente denominado, centro-oeste paulista, apesar de localizar-se no caminho percorrido pela Estrada de Ferro Noroeste do Brasil, não conseguiu que os trilhos ali aportassem. A EFNOB, que teve as obras iniciadas em 1905 em Bauru-SP, e seguia em direção a uma região praticamente não explorada pelo homem branco, sem ocupação urbana, no rumo do atual Mato Grosso do Sul, diferentemente do esperado, passa ao largo da vila. Contudo, vinte anos mais tarde, a cidade conseguiu desenvolver-se a ponto de ser conectada a linha tronco através de um ramal. Sendo assim, este trabalho busca discorrer sobre a formação peculiar do município, analisar sua relação com a ferrovia e determinar quais fatores o levaram a se desenvolver de maneira célere, mesmo a distância dos trilhos e, ainda, sob quais influências a construção do ramal ocorreu. A metodologia a ser empregada divide-se em quatro etapas: 1ª - A Formação de cidades em São Paulo durante a expansão cafeeira. 2ª - A história da cidade de Pirajuí e sua relação com a ferrovia. 3ª - Levantamento dos trajetos da EFNOB em relação a Pirajuí. 4ª - Investigação sobre quais os fatores levaram a criação do Ramal Pirajuhy, junto a linha tronco da EFNOB. Resultados esperados: Ampliação do conhecimento sobre a história das formações urbanas no estado, sua relação com o café, a ferrovia, e verificar as influências que norteavam as transformações urbanas da época. / The coffee expansion period from mid-nineteenth century and early twentieth century was crucial to the process of creation of cities in São Paulo, accompanied simultaneously by the railroad toward the state mottos. Pirajuí, located in what is now called the center-west of São Paulo, although locate on the path taken by Brazil Northwestern Railroad did not get the rails go through there. The EFNOB, which started in 1905 in Bauru-SP, and headed toward a region practically unexplored by the white man, without urban occupation, in the direction of the present Mato Grosso do Sul, village. However, twenty years later, the city was able to develop to the point of being connected to the trunk line through a branch. Thus, this work seeks to discuss the peculiar formation of the municipality, to analyze its relation with the railroad and to determine what factors led it to develop in a fast way, even the distance of the rails, and still under what influences the construction of the branch occurred. The methodology to be used is divided into four stages: 1 - The formation of cities in São Paulo during the coffee expansion. 2ª - The history of the city of Pirajuí and its relation with the railroad. 3rd - Survey of the EFNOB routes in relation to Pirajuí. 4th - Investigation of the factors that led to the transfer of the EFNOB trunk line. Expected results: Expansion of knowledge about the history of urban formations in the state, its relationship with the coffee, the railroad, and check the influences that shaped the urban transformations of this period.
39

Las sequías de la región del Noroeste Argentino y su relación con las temperaturas costeras superficiales del mar / Las sequías de la región del Noroeste Argentino y su relación con las temperaturas costeras superficiales del mar

Bobba, María Elvira, Minetti, Juan Leonidas 10 April 2018 (has links)
The main source of water vapor in the terrestrial climatic system is in the oceans. Warm waters favor the evaporation processes and air vertical movements, while cold waters brings decrements of the processes and the air remains stratified.Much research has been made to show the importance of the atmosphere-ocean interaction in generating the atmospheric fluctuations responsible for the rains and droughts on the continents. Northwestern Argentina is closer to the Pacific Ocean than the Atlantic. However, mostwater vapor comes from the latter due to the orographic conditions: there are mountain chains that affect significantly the regional climate, especially the geographic distribution of rainfall. In this paper I want to investigate the influence of thermic fluctuations of the Pacific and Atlantic oceans surface waters in rainfall variation. To do this, I used monthly data of the thermic anomalies in the coastal stations: Lima, Río de Janeiro, and Rio Gallegos in the period 1951-1980. It was also considered the regional drought index of that period. A contingency and correlation analysis was used for each month per year, the month in itself (diagnostic) and six months before (prognostic) between the drought index of the NOA (IS) with the thermic indexes of the Pacific and Atlantic continental borderlands in two latitudes: tropical and sub-polar.It was found that the regional droughts of the NOA are related mainly to the thermic negative anomalies of the coastal oceanic waters. / La principal fuente de vapor de agua del sistema climático terrestre se encuentra en las superficies oceánicas. Las aguas cálidas favorecen los procesos de evaporación y ascensos de aire, mientras que con las frías decrece este proceso y el aire superficial se estratifica. Numerosas investigaciones se realizaron para demostrar la importancia de la interacción atmósfera-océano en la generación de fluctuaciones atmosféricas que darían lugar a períodos de lluvias o sequías sobre los continentes.Por su posición geográfica el Noroeste Argentino (NOA) se encuentra más cerca del océano Pacífico que del Atlántico. Sin embargo, recibe de este último el principal aporte de vapor de agua, pues la configuración del relieve no ofrece obstáculos para la llegada del mismo a la región; en cambio está aislada del océano Pacífico por la Cordillera de los Andes Occidentales, que a esta latitud muestra una configuración compacta. Una impronta de la región del NOA es la presencia de cordones montañosos, que influyen en forma decisiva en el clima regional, específicamente en la distribución espacial de las precipitaciones. Uno de los papeles que les toca desempeñar es el de inducir a las masas de aire a elevarse por efecto orográfico, obligándolas a ascender.En este trabajo se quiere averiguar la influencia que ejercen sobre la variación de las precipitaciones, en una región mediterránea como la del NOA, las fluctuaciones térmicas de lasaguas superficiales de los flancos oceánicos atlántico y pacífico. Fueron utilizados datos mensuales de las anomalías térmicas de las estaciones costeras: Lima, Río de Janeiro y Río Gallegos como indicadoras de las temperaturas del mar adyacente, correspondiente al período 1951-1980. También se consideró el índice de sequía regional para igual período.Fueron empleados análisis de contingencia y correlación para cada mes del año, del mes consigo mismo (diagnóstico) y seis meses hacia atrás (pronóstico) entre el índice de sequía del NOA (IS) con los índices térmicos del borde continental pacífico y atlántico, este último en dos latitudes, tropical y subpolar.Se ha encontrado que las sequías regionales del NOA se relacionan preferentemente con anomalías térmicas negativas de las aguas oceánicas costeras.
40

Régulation des cycles biogéochimiques par les communautés microbiennes pélagiques sous influence de perturbations physiques à méso-échelle / Control of biogeochemical cycles by microbial pelagic communities under the influence of meso-scale physical perturbations

Severin, Tatiana 23 September 2014 (has links)
Les épisodes de convection en milieu hauturier sont des processus physiques hivernaux récurrents, mais irréguliers, ayant un fort pouvoir perturbateur sur l’écosystème pélagique. Les principaux objectifs de ma thèse ont été d’étudier l’influence d’épisodes de convection en Méditerranée Nord Occidentale sur les cycles biogéochimiques (distribution et bilan des sels nutritifs) et d’évaluer leurs impacts sur le compartiment microbien (abondance, activité et diversité). Ces travaux reposent sur mon implication active dans les campagnes océanographiques CASCADE (mars 2011) et DeWEX (février et avril 2013) qui s’inscrivent dans le cadre du chantier Méditerranée Mistrals (WP3 et WP1 respectivement du programme MermEX). Nous avons estimé que les apports en sels nutritifs lors d’un seul phénomène de convection de "moyenne envergure" étaient équivalents aux apports annuels des rivières et des dépôts atmosphériques à l’échelle du golfe du Lion, et pourraient soutenir une production primaire nouvelle de l'ordre de 46 à 63 g C.m-2.a-1 (i.e. l'ordre de grandeur de la production nouvelle annuelle de la zone). Une approche satellitale nous a permis de suivre l’évolution de plusieurs épisodes de convection et de mettre en évidence un étroit couplage entre ce type de forçage physique et le développement de blooms phytoplanctoniques en Méditerranée Nord Occidentale. Pour aborder le rôle des microorganismes dans la régulation des cycles biogéochimiques en réponse à ces épisodes de convection, nous avons identifié l’influence relative des forçages physico-chimiques sur les changements de diversité des communautés microbiennes (bactéries et archées identifiées par pyroséquençage), ceci en relation avec leur activité de reminéralisation de la matière organique. Nous avons également utilisé les épisodes de convection pour évaluer la pertinence écologique des écotypes de SAR11, Marine group I et Marine group II, les 3 groupes taxonomiques les plus répandus et abondants en Méditerranée et dans tous les océans du monde. Ces travaux ont permis de proposer des scénarii cohérents de l'évolution potentielle des écosystèmes pélagiques en Méditerranée Nord Occidentale dans un contexte de changement climatique global. En effet, mon étude est une contribution à la compréhension de la réponse potentielle des écosystèmes pélagiques à la modification attendue de la fréquence et/ou de l'intensité des processus de convection. / Open-ocean convection episodes are recurrent winter physical processes, but irregular in intensity, with a strong disruptive effect on the pelagic ecosystem. My principal thesis objectives were to study the influence of the Northwestern Mediterranean convection on the biogeochemical cycles (nutrient distribution and assessment), and to evaluate their impacts on the microbial compartment (abundance, activity and diversity). This work was based on my active participation to the oceanographic cruises CASCADE (March 2011) and DeWEX (February and April 2013), which are incorporated in the framework of Mistral Mediterranean project (respectively in the WP3 and WP1 of MermEX program). We estimated that the nutrient supply by a single convection episode of “average-scale” was equivalent to the annual riverine discharges and atmospheric deposition in the golf of Lion. This could sustain a new primary production from 46 to 63 g C.m-2.a-1 (i.e. the annual new primary production rate of this area). A remote sensing approach allowed us to follow open-ocean convection episodes evolution, and to highlight the close relationship between this kind of physical forcing and the phytoplanktonic bloom development in the Northwestern Mediterranean. During the study of the impact of convection episodes on the role of microorganisms in the biogeochemical cycles regulation, we determined the influence of physical parameters and environmental factors on the modification of the microbial community diversity (pyrosequencing of Bacteria and Archaea), in relation with organic matter mineralization. Besides, we used convection mixing as a model to evaluate the ecological pertinence of SAR11, Marine group I and Marine Group II ecotypes, 3 taxonomic groups the most widespread and abundant in Mediterranean and in all the oceans. In a climate change context, my works allowed us to propose different coherent scenarios of the potential evolution of the Northwestern Mediterranean pelagic ecosystems. My study contribute to the understanding of the pelagic ecosystem evolution with the predictable modifications in frequency and/or intensity of open-ocean convection processes.

Page generated in 0.0717 seconds