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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.
161

The geomorphological development of ephemeral and relict river valley systems in the north part of the Iraqi Western Desert

Hamed, Waleed Hanosh January 2015 (has links)
This research project provides a geomorphological and geological analysis of ephemeral and relict river valley systems in the north part of the Iraqi Western Desert. The area surveyed covers approximately 30 000 km2 and is one of the remotest and least studied parts of the Arabian Peninsula. Part of the reason for the lack of research in this area in recent years has been the ongoing security problems and all fieldwork undertaken for this thesis was carried out with the support of armed guards and police. In addition much of the work on the geology and geomorphology of the region is in confidential files commissioned by oil companies, and in MSc and PhD theses held in Iraqi Universities. A significant part of this work and indeed many scientific papers, are only available in Arabic. Therefore a major element of the work for this thesis has been to translate this material and make the results available in English for the first time. The study demonstrates that the present surface of the Iraqi Western Desert overall forms an incised plateau developed during two phases of continental erosion and deposition during the Tertiary and Quaternary periods. The first phase started after Oligocene uplift formed an older plateau within the Oligocene Tayarat formation. This plateau is characterized by denudation processes associated with a semiarid climate, including the formation of subsurface hollows and caves. The second phase, which began after the last Alpine Orogenic movement, and includes the Pliocene and Quaternary periods, formed a younger plateau developed on the Zahra formation. This younger plateau is characterized by processes indicative of climatic fluctuations from wet to arid and semiarid, which induced denudation in places and deposition in others. However, in terms of the geomorphological landforms present in the Western Desert they can be broadly divided into: i) Structural and erosion-denudation forms ii) Accumulation forms Lithology landform in these two categories has resulted in the production of a new geomorphological map of the Iraqi Western Desert. A key component of this map uses the drainage networks. Four distinct drainage systems were identified: 1. The valleys which descend from west to east. These valley systems are located to the south and south east town of Rutba 2. The valleys which descend from south to north. These lie to the west and southwest of Rutba and are controlled by the north to south strike of exposed Palaeogene strata. 3. The valleys which descend from east south to north west, located north of the Garaa area like Ratga and Akash. 4. The valleys which descend from east to west. These valley systems are located to the south and south west town of Rutba, like Swab and Wallaj valleys. Investigation of these four networks established that they were relict systems that still carried ephemerally active misfit rivers and stream. The overall control on their form was the alternating sequences of variable strength rocks that were exposed and eroded as part of the uplift of an anticlinorium (Houran) and anticline (Garaa), associated with the Alpine Orogeny .However, the unclearing Structures were much older and can be traced back to Permian tectonic processes. The drainage of the Western Desert, therefore, is antecedent and controlled by Tertiary and Quaternary tectonics. The rivers appear to have active throughout the Pleistocene incising into the Western Desert plateaux. Highest incision rates probably occurred during more pluvial periods in the Pleistocene which may have been coincident with glacial marine in the Northern Hemisphere. The contemporary rivers are misfit within larger valleys although still subject to flash floods under the right metrological condition.
162

Rose Care in the Low Desert

Bradley, Lucy, Coffman, MaryLou 06 1900 (has links)
4 pp. / This publication contains guidelines for watering, cultivating and fertilizing roses. It also contains Monthly check sheet for rose care.
163

DETERMINANTS OF COMMUNITY STRUCTURE IN DESERT RODENTS: RISK, RESOURCE AND FORAGING BEHAVIOR.

KOTLER, BURT PHILIP. January 1983 (has links)
Communities of granivorous desert rodents are structured by habitat selection and may be influenced by either predatory risk or resources. To examine these hypotheses, I manipulated illumination using lanterns, parachute canopies, or natural moonlight and resources using seeds. Foraging behavior is risk-sensitive; increased illumination reduces foraging in open areas while adding shadows to open areas using parachutes increases foraging there. Foraging behavior is also affected by resource enrichments. Differences among species in habitat selection were determined by specific abilities to detect and avoid predators. The least vulnerable species, Dipodomys deserti, foraged heavily in the open and was largely unaffected by treatments; other species of kangaroo rats and kangaroo mice also prefer the open, but responded to both risk and resource manipulations; highly vulnerable Peromyscus maniculatus was always restricted to bushes even under the most favorable circumstances; Perognathus longimembris was restricted to bushes in the absence of P. maniculatus in 1980 and was displaced from preferred microhabitats by the presence of kangaroo rats in 1981. A correlation between auditory bullar volume and use of open habitat by the various species in this community suggests that predatory risk provides an axis along which habitat segregation occurs. Predation can shape community structure by influencing foraging decisions of individuals. Desert rodents from North America and the Middle East have converged morphologically and perhaps in behavior and in community structure. Using desert rodent communities in the Great Basin Desert of U.S.A. and in the Negev Desert of Israel, I manipulated predatory risk in both communities and noted that foraging activity declines with increased predatory risk. Additional evidence suggests that predation also affects habitat selection behavior in both communities. Furthermore, differences in habitat utilization among species which promotes coexistence are related to morphological anti-predator specialization of the species. Predation appears to have shaped behavior and contributed to community structure in similar ways in both communities.
164

DIEL ACTIVITY OF FEMALE DESERT BIGHORN SHEEP IN WESTERN ARIZONA

Alderman, Jay Allen, 1961- January 1987 (has links)
I studied diel activity patterns of female desert bighorn sheep ( Ovis canadensis mexicana) in the Little Harquahala Mountains, Arizona, July 1985-June 1986. Diurnal activity patterns were similar throughout the year. Nocturnal activity patterns were similar for all seasons except spring when activity significantly (P = 0.003) decreased. Bighorn sheep were active an average of 39 and 33% of any given hour during the day and night, respectively. Diurnal ambient temperatures and relative humidity were significantly (P ≤ 0.048) correlated with bighorn sheep activity during all seasons. Bighorn sheep spent a majority of the time foraging in the fall and winter, but spent more time resting during spring and summer. Bighorn sheep obtain water in their food throughout the day; percent moisture content of forage species remained high (≥ 32%) for any given hour of the day throughout the year.
165

Body Shape Diversification of Pecos Pupfish (Cyprinodon Pecosensis) on Varying Habitats as Evaluated by Geometric Morphometrics

Xu, Qianna 01 April 2017 (has links)
During the 19th and 20th centuries, alterations to the Pecos River in New Mexico and Texas, USA due to anthropogenic activities, including damning and river channelization, vast water extraction for irrigation, as well as pollution of associated habitats, have greatly impacted the fish fauna within the drainage. One of the endemic fish species, the Pecos pupfish (Cyprinodon pecosensis), might be the most affected. Historically abundant and widespread large populations have been disrupted and became a series of small isolated subpopulations that persist at a few highly fragmented habitats restricted to a small area in southern New Mexico. The connectivity among these habitats is extremely low, and can potentially prevent any gene flow among subpopulations, which might eventually result in morphological divergence among subpopulations in face of different ecological conditions. Here I utilized landmark-based Geometric Morphometrics to evaluate body shape variation of the Pecos pupfish at 26 different localities categorized into four general habitat types that each differ greatly in ecological properties. Results from this study suggest that, despite significant sexual dimorphism, body shape morphology of Pecos pupfish varied in response to spatial heterogeneity and it was most intensely influenced by specific localities within habitat types. There were overlaps of the convex hull regions of morphospace among the four habitat types, implying that ecomorphological dynamics of the Pecos pupfish were rather site-specific. Moreover, temporal variation of body morphology was statistically significant but not comparable to body shape variation among different localities. The empirical data collected from this study provides preliminary evidence for phenotypic diversity of Pecos pupfish in varied ecological conditions, which has important implications for the future conservation management of Pecos pupfish diversity and viability. Such implications could be extended to other endemic desert fishes in disrupted habitats.
166

Anthropocene in the Geomorphology of the Sonoran Desert

January 2019 (has links)
abstract: Human endeavors move 7x more volume of earth than the world’s rivers accelerating the removal of Earth’s soil surface. Measuring anthropogenic acceleration of soil erosion requires knowledge of natural rates through the study of 10Be, but same-watershed comparisons between anthropogenically-accelerated and natural erosion rates do not exist for urbanizing watersheds. Here I show that urban sprawl from 1989 to 2013 accelerated soil erosion between 1.3x and 15x above natural rates for different urbanizing watersheds in the metropolitan Phoenix region, Sonoran Desert, USA, and that statistical modeling a century of urban sprawl indicates an acceleration of only 2.7x for the Phoenix region. Based on studies of urbanization’s erosive effects, and studies comparing other land-use changes to natural erosion rates, we expected a greater degree of urban acceleration. Given that continued urban expansion will add a new city of a million every five days until 2050, given the potential importance of urban soils for absorbing anthropogenically-released carbon, and given the role of urban-sourced pollution, quantifying urbanization’s acceleration of natural erosion in other urban settings could reveal important regional patterns. For example, a comparison of urban watersheds to nearby non-urban watersheds suggests that the Phoenix case study is on the low-end of the urban acceleration factor. This new insight into the urban acceleration of soil erosion in metropolitan Phoenix can help reduce the acute risk of flooding for many rapidly urbanizing desert cities around the globe. To reduce this risk, properly engineered Flood Control Structures must account for sediment accumulation as well as flood waters. While the Phoenix area used regional data from non-urban, non-desert watersheds to generate sediment yield rates, this research presents a new analysis of empirical data for the Phoenix metropolitan region, where two regression models provide estimates of a more realistic sediment accumulation for arid regions and also urbanization of a desert cities. The new model can be used to predict the realistic sediment accumulation for helping provide data where few data exists in parts of arid Africa, southwest Asia, and India. / Dissertation/Thesis / Doctoral Dissertation Geography 2019
167

Suppositions for Desert Modernism: An Architectural Framework Informed by Climate, Natural Light, and Topography

January 2019 (has links)
abstract: The aim of this research study is to develop a passive architectural design morphology, tuned to the Sonoran Desert, which redefines Desert Modernism and integrates: (a) mitigation of heat transfer through the exterior envelope, and (b) use of daylight to inform appropriate architectural massing. The research investigation was delimited to mid-nineteenth century European modernist examples, and ends with mid-twentieth century modern architecture in the southwestern United States as viewed through the lens of environmental design. The specific focus was on Desert Modernism, a quasi-architectural movement, which purportedly had its beginnings in 1923 with the Coachella Valley, Popinoe Desert Cabin. A mixed-method research strategy comprised of interpretive-historical research, virtual simulation/modeling analysis and logical argumentation is used. Succinct discussions on desert vernacular design, Modernism’s global propagation, and the International Style reinterpretations were illustrated to introduce the possibility of a relationship between Modernism and the vernacular. A directed examination of climatic responses included within examples of California Modernism, the Case Study Houses and Desert Modernism follows. Three case studies: a) the Frey House II, b) the Triad Apartments, and c) the Analemma House were assessed using virtual simulation and mathematical calculations, to provide conclusive results on the relevance of regionally tuned exterior envelope design and planning tactics for the Phoenix, Arizona area. Together, these findings suggest a correlation between environmental design principles, vernacular architecture, and Modernism. / Dissertation/Thesis / Doctoral Dissertation Architecture 2019
168

Monitoring Desert Ungulates via Fecal DNA-Based Capture Recapture

Pfeiler, Stephen S. 01 May 2019 (has links)
Estimates of population abundance and survival are critical for effective wildlife management. Obtaining estimates of these kind using traditional wildlife monitoring techniques (i.e. ground and aerial surveys) has proven to be difficult, especially for species that are wide ranging and exist in small, patchily distributed populations. My objective was to implement fecal DNA-based capture-recapture surveys to estimate abundance and survival of two different ungulate populations that inhabit the deserts of southeastern California. I also compared fecal DNA-based capture-recapture techniques to traditional methods by evaluating the costs and precision associated with both methods. Using artificial water sources as focal sampling sites, I performed sampling during the summers of 2015, 2016, and 2017 in the Mojave and Sonoran Deserts of California. I was able to obtain reasonably precise estimates of abundance and survival for both species. To my knowledge, my study provides the first abundance and survival estimates of desert mule deer in California in over 13 years. Additionally, my study shows that when compared to traditional methods, fecal DNA-based capture recapture techniques can achieve much higher precision at a fraction of the cost.
169

Manöverkrigföringens indirekta och direkta metod : en studie i fördelningen av dessa vid flyginsatser under Operation Desert Storm

Deretic, Goran January 2009 (has links)
<p>En av huvuddelarna i manöverkrigföringen, som Försvarsmakten nyttjar, är indirekt och direkt metod. Men då Sverige inte har varit i krig på väldigt länge så beslöt jag att skriva denna uppsats i syfte att skapa ett underlag för en ökad förståelse för nyttjandet av indirekt och direkt metod vid manöverkrigföring. För att göra detta så försökte jag svara på följande fråga:</p><ul><li>Hur ser fördelningen mellan indirekt och direkt metod ut vid flyginsatser i krig under 1990-talet?</li></ul><p>För att få ett svar på frågan så gjorde jag en fallstudie på Operation Desert Storm där jag först analyserade vilken metod de allierade styrkorna använde mot de olika anfallsmålen. Efter detta gjorde jag en undersökning i hur många anfall och uppdrag som genomfördes mot varje mål. Resultaten visade bland annat att även om de flesta målen var kritiska sårbarheter, där indirekt metod nyttjades, så gjordes de flesta anfallen med direkt metod.</p> / <p>A fundamental part of the manoeuvre warfare, which the Swedish Armed Forces use, is indirect and direct approach. But since Sweden has not been in a war for a long time I decided to write this essay with the purpose to create a basis of further understanding of how to use indirect and direct approach during manoeuvre warfare. To do this I have tried to answer the following question:</p><ul><li>How are the indirect and direct approach divided in air raids in wars during the 1990s?</li></ul><p>To answer this question I made a case study on Operation Desert Storm, where I first analysed which approach the allied forces used on the different targets. After that I made a research on how many attacks and missions they made on each target. The results showed among others that even though most of the targets were critical vulnerabilities, on which the indirect approach was used, the most part of the attacks were made using the direct approach.</p>
170

Manöverkrigföringens indirekta och direkta metod : en studie i fördelningen av dessa vid flyginsatser under Operation Desert Storm

Deretic, Goran January 2009 (has links)
En av huvuddelarna i manöverkrigföringen, som Försvarsmakten nyttjar, är indirekt och direkt metod. Men då Sverige inte har varit i krig på väldigt länge så beslöt jag att skriva denna uppsats i syfte att skapa ett underlag för en ökad förståelse för nyttjandet av indirekt och direkt metod vid manöverkrigföring. För att göra detta så försökte jag svara på följande fråga: Hur ser fördelningen mellan indirekt och direkt metod ut vid flyginsatser i krig under 1990-talet? För att få ett svar på frågan så gjorde jag en fallstudie på Operation Desert Storm där jag först analyserade vilken metod de allierade styrkorna använde mot de olika anfallsmålen. Efter detta gjorde jag en undersökning i hur många anfall och uppdrag som genomfördes mot varje mål. Resultaten visade bland annat att även om de flesta målen var kritiska sårbarheter, där indirekt metod nyttjades, så gjordes de flesta anfallen med direkt metod. / A fundamental part of the manoeuvre warfare, which the Swedish Armed Forces use, is indirect and direct approach. But since Sweden has not been in a war for a long time I decided to write this essay with the purpose to create a basis of further understanding of how to use indirect and direct approach during manoeuvre warfare. To do this I have tried to answer the following question: How are the indirect and direct approach divided in air raids in wars during the 1990s? To answer this question I made a case study on Operation Desert Storm, where I first analysed which approach the allied forces used on the different targets. After that I made a research on how many attacks and missions they made on each target. The results showed among others that even though most of the targets were critical vulnerabilities, on which the indirect approach was used, the most part of the attacks were made using the direct approach.

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