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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.
51

Seasonal influences on food availability and diet of coastal cutthroat trout in relation to riparian vegetation

Romero, Nicolas 19 December 2003 (has links)
Current riparian management objectives in the Pacific Northwest promote both retention of existing conifers and conversion of hardwood-dominated areas to conifers. Although understanding of relationships between riparian vegetation and salmonid prey availability is growing, temporal variation in these relationships is poorly understood. Seasonal fluxes in availability of aquatic and terrestrial invertebrate prey for coastal cutthroat trout (Oncorhynchus clarki clarki) were investigated by estimating invertebrate biomass from aquatic (benthos and drift) and allochthonous (terrestrial) sources in three watersheds in the Oregon Coast Range. To investigate the influence of vegetation type on food sources, samples were collected in each watershed from stream sections dominated by deciduous, conifer, and mixed vegetation. During each sample period, diet was assessed by examining gut contents of captured trout. Stream discharge appeared to be an influential factor regulating seasonal fluxes of aquatic invertebrate biomass in the benthos and drift. Total allochthonous invertebrate biomass at deciduous and mixed vegetation sites (64 and 61 mg·m⁻²·day⁻¹, respectively) was almost 30% higher than at coniferous sites (45 mg·m⁻²·day⁻¹). Although aquatic insects dominated the total gut contents during this study, prey from terrestrial origin was more common during summer and fall. These results suggest that systematic removal of deciduous vegetation in riparian zones to promote conifers may have unintended consequences on the food resources of coastal cutthroat trout and the productivity of aquatic food webs in the Pacific Northwest. / Graduation date: 2004
52

Mining in national parks : a case study--An integrated environmental evaluation of possible magnesite mining in Weetootla Gorge within the Gammon Ranges National Park, South Australia

Stoll, J. A. E. (Julie-Ann E.) January 1989 (has links) (PDF)
Bibliography: leaves 146-152.
53

Similarities in understory vegetation composition between unthinned, thinned and old-growth Douglas fir stands in western Oregon

Mayrsohn, Cheryl 13 September 1995 (has links)
Forest stands were studied to determine if old-growth forest structure could be mimicked in younger stands via overstory manipulation. Cover and species composition of understory plants were systematically sampled in sixteen thinned second-growth stands and sixteen adjacent unthinned second-growth Douglas fir (Pseudotsuga menziesii (Mirabel) Franco.) stands. The stands were thinned twenty-four to thirteen years ago. These were compared to seven nearby old-growth stands. Thinned and unthinned stands had matching elevations, aspect, and soils, yet differed primarily in management treatment. Leaf area indices were determined for these stands. Thinned stands differed from the old-growth and unthinned stands in having significantly higher cover values and species numbers, apparently resulting from increased light to the forest floor and a greater variety of microhabitats created by thinning. Young unthinned and old-growth stands were comparable in terms of cover and richness, but differed in species composition. Diversity indices showed no difference in species diversity between the three types of stands. Ordination of the species/sample data using Detrended Correspondence Analysis showed that understory species composition of the young unthinned and thinned stands was nearly identical. Species composition of old-growth stands differed from thinned and unthinned stands. The ordination indicated that age of the stands, structure of the canopy layers and climate were major determining factors in the species composition of the understory plant communities. Management manipulation of the second growth stands did not yield stands with understory vegetation communities that mimicked those of old-growth stands. The conclusions of this study were: 1) Shrub cover increased with thinning as compared to unthinned and old-growth stands. 2) Thinning increased the species richness of the stands, without increasing the number of exotics. 3) Diversity was not altered by thinning. Old-growth, thinned and unthinned stands did not differ in diversity values. 4) Patterns of community composition in thinned stands were more similar to unthinned equivalent stands than to nearby old-growth. / Graduation date: 1996
54

The effects of forage improvement practices on Roosevelt elk in the Oregon Coast Range

Stussy, Rosemary J. 06 December 1993 (has links)
Forage availability, diets, distribution, and productivity were compared for Roosevelt elk, Cervus elaphus roosevelti, using improved (i.e. seeded, fertilized, and grazed) and untreated areas of the Oregon Coast Range. Seasonal forage availability was substantially different on 1-year-old improved and untreated clearcuts, but the differences diminished by clearcut age 4 and essentially disappeared by clearcut age 7. Elk diets, as evaluated by fecal analysis, were similar in plant species composition and DAPA concentrations on both areas. There was no significant difference in estimated calf birth weights or survival, or in pregnancy and lactation rates, kidney and metatarsal marrow fat concentrations, or breeding dates of adult cows using improved and untreated areas. Summer and winter calf ratios were similar in 7 of 8 seasons sampled. There was no significant difference in home range or core area size, and distances traveled were similar on both areas in all seasons except winter. Elk exposed to summer sheep grazing were displaced an average of 1211 m (SD = 28 m) for an average of 14 weeks (SD = 5 weeks). Elk using improved areas stayed closer to forage areas in spring, but otherwise there was no significant difference in proximity to forage. Elk from both areas demonstrated preferential use of meadows, and used other forage areas in proportion to their availability. The combined results indicated that the forage improvement practices were ineffective in producing any measurable benefits for elk. / Graduation date: 1994
55

Regional biodiversity management strategy : case study on the Flinders Ranges

Dorjgurhem, Batbold. January 1999 (has links) (PDF)
Bibliography: leaves 107-117. This thesis examines the rationale for managing biological diversity on a regional basis and develops recommendations for the use of two computational methods in biodiversity management planning by conducting a case study in the Flinders Ranges, centred on the Yellow-footed Rock Wallaby (abstract)
56

FOUNDATION INITIATIVE 2010: THE FOUNDATION FOR RANGE INTEROPERABILITY

Rumford, George J., Vuong, Minh, Bachinsky, Stephen T., Powell, Edward T. 10 1900 (has links)
International Telemetering Conference Proceedings / October 22-25, 2001 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Foundation Initiative 2010 (FI 2010) is a joint interoperability initiative of the Director, Operational Test and Evaluation. The vision of FI 2010 is to enable interoperability among ranges, facilities, and simulations in a timely and cost-efficient manner and to foster reuse of range assets and future range system developments. To achieve this vision, FI 2010 is developing and validating a common architecture with a common range object model, a core set of tools, inter-range communication capabilities, interfaces to existing range assets, interfaces to weapon systems, and recommended procedures for conducting synthetic test events and training exercises. During FY 01, the project is developing the second Test and Training ENabling Architecture (TENA) Middleware Prototype as a basis for range communication. FI 2010 will advance a simulation-based acquisition or a ‘distributed engineering plant’ methodology to streamline weapon system acquisition. Benefits from the FI 2010 products include cost effective replacement of customized data links, enhanced exchange of mission data, organic TENA-compliant capabilities at test sites to be leveraged for future test events, and instrumentation system reuse. Through FI 2010, future inter-range operations, instrumentation development, and range capability sustainment will cost less and incur less risk.
57

Application of GPS to Hybrid Integrated Ranges and Simulations

Van Wechel, R. J., Jarrell, R. P. 11 1900 (has links)
International Telemetering Conference Proceedings / October 30-November 02, 1995 / Riviera Hotel, Las Vegas, Nevada / GPS user equipment has matured and is now available to support the use of live players in integrated ranges and simulations. P-code GPS provides true WGS-84 based coordinate information anywhere in the world at any time and to accuracies at the 5 ft (1s) level (demonstrated in high dynamic aircraft using differential P-code GPS). C/A code GPS shows lower accuracy and is especially vulnerable to multipath degradation over water. In supporting networked ranges with simulations, GPS is directly applicable to the dead reckoning requirements of the Distributed Interactive Simulation (DIS) community. DIS dead reckoning provides the capability of much reduced data rates in recovering TSPI information from platforms. The on-board state vector for an integrated GPS/Inertial Reference Unit provides accurate position, velocity and acceleration as well as attitude and attitude rate information so that dead reckoning thresholds can be both position and attitude driven. A simplified analysis is presented in the paper to derive dead reckoning update rates from the G loading levels of various player dynamics. Also, information is provided which results in word length requirements for GPS-based state vector information for transmission over minimum word length DIS Field Instrumentation Protocol Data Units (PDUs, which are the data block formats). The coordinate frame problem in use of GPS-based state vector information from fixed ranges is also addressed, showing that the use of a local geodetic frame is preferable to the use of an earth centered earth fixed frame, in that it is more efficient of network PDU word length.
58

Long-term tectonothermal history of Laramide basement from zircon–He age-eU correlations

Orme, Devon A., Guenthner, William R., Laskowski, Andrew K., Reiners, Peter W. 11 1900 (has links)
The long-term (>1 Ga) thermal histories of cratons are enigmatic, with geologic data providing only limited snapshots of their evolution. We use zircon (U-Th)/He (zircon He) thermochronology and age composition correlations to understand the Proterozoic-Phanerozoic thermal history of Archean Wyoming province rocks exposed in the northern Laramide ranges of western North America. Zircon He ages from the Wind River Range (54 dates) and Bighorn Mountains (32 dates) show negative correlations with effective uranium (eU), a proxy for radiation damage. Zircon dates from the Bighorns are between 960 Ma (low-eU) and 20 Ma (high-eU) whereas samples from the Wind Rivers are between 582 Ma (low-eU) and 33 Ma (high-eU). We applied forward modeling using the zircon radiation damage and annealing model ZrDAAM to understand this highly variable dataset. A long-term t-T path that is consistent with the available geologic constraints successfully reproduced age-eU correlations. The best fit to the Wind Rivers data involves two phases of rapid cooling at 1800-1600 Ma and 900-700 Ma followed by slower cooling until 525 Ma. During the Phanerozoic, these samples were heated to maximum temperatures between 160 and 125 degrees C prior to Laramide cooling to 50 degrees C between 60 and 40 Ma. Data from the Bighorn Mountains were successfully reproduced with a similar thermal history involving cooler Phanerozoic temperatures of similar to 115 degrees C and earlier Laramide cooling between 85 and 60 Ma. Our results indicate that age-eU correlations in zircon He datasets can be applied to extract long-term thermal histories that extend beyond the most recent cooling event. In addition, our results constrain the timing, magnitude and rates of cooling experienced by Archean Wyoming Province rocks between recognized deformation events, including the >1 Ga period represented by the regionally-extensive Great Unconformity.
59

Sistema integrado de diagnose (DRIS) para a cultura do algodão no município de Silvânia-Goiás / Diagnosis and recommendation integrated system (DRIS) for cotton crop at the Silvânia-Goiás(Brazil) city

SOUZA, Roberta de Freitas 18 February 2009 (has links)
Made available in DSpace on 2014-07-29T16:24:20Z (GMT). No. of bitstreams: 1 Dissertacao Roberta de Freitas.pdf: 4201818 bytes, checksum: 579a958eeb338558fbaeb619d7c9df7e (MD5) Previous issue date: 2009-02-18 / The Diagnosis and Recommendation Integrated System (DRIS) is an efficient tool for nutritional diagnosis on several crops. However, it no longer has been used on cotton crop, mainly in Goiás State. This work aimed to gain DRIS norms and diagnose the most limiting nutritional factors to obtain high cotton yields, using soil and leaf analysis, interpreted through critical levels or concentration ranges and DRIS techniques. Sampling sites were chosen on commercial area according to local topographic features and soil classes, trying to maintain their inside uniformity. Soil and leaf samples were taken at the full flowering stage (90 day after seeding). Ten leafs from each point were sampled, withdrawing the fifth leaf from the apex of the main stem, and for soil analysis six single samples from 0 to 20 cm at each point. Yields were assess after physiological maturation, taking two seeding rows five meters long for harvesting cotton fiber. Soil and leaf data were interpreted through DRIS and concentration ranges techniques. Norms were established from populations with yields greater than 4 Mg ha-1 of nutmeat cotton for calculating the DRIS indices. The diagnosis techniques assessed in this work showed distinct interpretations. The nutrients S, P, B, Zn, Fe and Mn showed to be the most limiting ones, as evaluated on by soil and analysis and diagnosed through the DRIS technique. Using the concentration range technique P, Zn and SOM in soil data, whereas in leaf data, S, Zn, K and B, are the most limiting ones. DRIS showed higher sensibility for diagnosing nutritional deficiencies, moreover, for micronutrients. / O Sistema Integrado de Diagnose e Recomendação (DRIS) tem mostrado-se eficiente como método para diagnóstico nutricional em diversas culturas. Porém o método tem sido pouco empregado na cultura do algodoeiro, principalmente no Estado de Goiás. O objetivo deste trabalho foi obter normas DRIS e diagnosticar os fatores nutricionais mais limitantes à obtenção de altas produtividades para a cultura do algodão, através de análises foliares e de terra, interpretadas pelos métodos faixas de concentração ou níveis críticos e DRIS. Foram selecionados pontos de amostragem, em uma área comercial no município de Silvânia, Goiás, conforme as características locais de topografia e tipo de solo, procurando-se manter uniformidade dentro dos pontos e diferenças entre eles. As amostras de terra e folha foram coletadas na época de florescimento pleno (90 dias após o plantio). Coletou-se 10 folhas em cada ponto, retirando-se a quinta folha a partir do ápice da haste principal, e para a análise de terra coletou-se seis amostras simples na profundidade de 0 a 20 cm para cada ponto, totalizando 108 pontos de amostragem. Para avaliação da produtividade em cada ponto de amostragem, após a maturação fisiológica, foram tomadas duas linhas de cinco metros lineares de plantio, colhendo-se as plumas. As análises de terra e folhas foram interpretadas pelos métodos das faixas de concentração ou níveis críticos e o DRIS. Foram estabelecidas normas a partir de uma população com produtividade maior que 4.000 kg ha-1 de algodão em caroço para cálculo dos índices DRIS. Os métodos de diagnose avaliados neste trabalho apresentaram interpretações distintas. Os nutrientes S, P, B, Zn, Fe e Mn foram os mais limitantes nas análises de terra e de folha, diagnosticados pelo método DRIS. Pelas faixas de concentração ou níveis críticos P, Zn e matéria orgânica foram os mais limitantes nas análises de terra, enquanto nas análises foliares foram os nutrientes S, Zn, K e B. O método DRIS apresentou maior sensibilidade para diagnosticar problemas nutricionais, especialmente, para micronutrientes.
60

Clay movement in a saline-sodic soil toposequence

Nathan, Muhammad. January 2001 (has links) (PDF)
Includes bibliographical references (leaves 78-86) In the Herrmanns sub-catchment in the Mt. Lofty Ranges (near Mt. Torrens) soil sodicity was the dominant factor in causing clay to disperse in the eroded area along the foot slopes, wheras in non-eroded areas of the mid-slopes and on the stream banks, the dispersive power of sodicity was attenuated by the flocculative power of other soil properties.

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