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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.
191

Petrology and Mineralogy of Quaternary Basalts, Gem Valley and Adjacent Bear River Range, Southeastern Idaho

Perkins, William D 01 May 1979 (has links)
Quaternary basalts of Gem Valley, Idaho, are present as valley fill (Group 1) and as well defined flows in the Bear River Range (Group 2) east of Gem Valley. Minerals present in both groups of basalts include olivine (Fo73 -Fo39), augite (Wo41 En39 Fs20), plagioclase (An75 -An40), and Fe-Ti oxides. Coexisting pairs of magnetite and ilmenite, and olivine and clinopyroxene in several samples indicate temperatures of crystallization from 958°c to 1167°c. The Group 2 basalts exhibit a cumulate texture with abundant large (2 cm) phenocrysts of plagioclase. Chemically, the Gem Valley basalts are similar to the basalts of the Snake River Plain with respect to SiO2, total Fe, P2O5 and Na2O but differ in the amounts of Al2O3 and MgO present. The Al2O3 is generally higher and the MgO is generally lower in the Gem Valley basalts. Comparing Group 1 with Group 2 basalts, the Group 2 basalts generally have more alumina and alkalis than the Group 1 basalts. Chemically both groups of basalt exhibit characteristics of the tholeiitic basalt suite, because they are hypersthene normative. Mineralogically, both groups of basalt contain but one pyroxene, augite, which is characteristic of the alkali-olivine basalt suite. This apparent contrast in classifications may be resolved by referring to these basalts as transitional between the alkali-olivine and tholeiitic basalt .suites, with the restriction that no genetic relationship to either suite is implied. Within the limits of this study, it is proposed that the Group 1 basalts may have formed by the partial melting of mantle material with a pyrolite composition. Furthermore, the Group 2 basalts appear to have originated as a result of the accumulation of plagioclase in a fractionating magma of Group 1 composition.
192

Environmental Analysis of the Upper Cambrian Nounan Formation, Bear River Range and Wellsville Mountain, North-Central Utah

Gardiner, Larry L. 01 May 1974 (has links)
The Nounan Formation in north-central Utah thickens northward from 696 feet near Causey Dam to 1147 feet at High Creek in the Bear River Range, and northwestward to 1149 feet at Dry Canyon in Wellsville Mountain. The basal contact of the Nounan Formation is sharp, but dolomite extends irregularly downward into limestones of the Bloomington Formation as much as 6 feet. The Nounan Formation is divided into three members based on lithologic characters: (1) a lower member composed of dark, medium-crystalline dolomite; (2) a middle member composed of white, coarse-crystalline dolomite with tongues of dark dolomite; and (3) an upper member of interbedded light and dark dolomites and limestones with local arenites and sandy carbonates. The lower member was deposited in a high-energy, shallow-marine subtidal to intertidal environment. Evidence includes sets of low-angle cross stratification (dunes), oncolites, oolites, and rip-up clasts. The middle member forms distinctive ledges and cliffs. The presence of thinly laminated algal stromatolites and relict structures seen also in the lower member indicate a subtidal to intertidal environment similar to that inferred for the lower member. The white color and coarse crystallinity may have resulted from recrystallization of the dark, finer grained dolomite that comprises the lower member. The upper member is characterized by lithologic variability. Thicknesses of limestone are greatest in the north, and decrease to only a few feet in the south. Quartz and other terrigenous minerals are scattered at intervals throughout the upper member, with a marker of sandy (arenaceous) dolomites at the base and near the middle and an increase of sand near the top also. The upper contact, with quartz-rich arenites (subarkosic quartzites) of the Worm Creek Member of tho St. Charles Formation, is gradational overall, but is sharp and planar in each section and readily located. In the upper member, algal mats trapped a varying but overall increasing influx of quartz and feldspar, probably in shallow subtidal environments, and vertically stacked hemispheroids suggest that depositional conditions may have included intertidal. Virtually all of the dolomite in the Nounan Formation must have formed by replacement of lime sediments by downward-moving high-magnesium brines. It is that these brines originated in restricted, shallow, subtidal evaporating basins, such as the Great Bahama Banks today, and associated supratidal flats. Lateral changes from limestone to dolomite overall and also in individual beds of the upper member indicate that the brines travelled laterally as well as vertically, and dolomitization may have been limited as much by prior diagenetic alteration and cementation as by the volume, concentration, and proximity of the brine itself.
193

Bear River Heritage Area: A Study of Recreation Specialization and Importance-Performance

Baird, Tyler A. 01 May 2013 (has links)
Heritage tourism is a fast growing sector in the recreation arena. Research into multiple aspects of heritage tourism has increased during the last few decades as it has been recognized as a distinct form of tourism and promoted around the globe. This study was conducted in an effort to better understand multiple aspects of heritage tourism in the Bear River Heritage Area of northern Utah and southeastern Idaho. The following aims to provide Bear River Heritage Area leadership with baseline data on their visitors and build upon the base of literature in the areas of recreation specialization, and importance-performance analysis. Attempts to apply the recreation specialization continuum in the context of heritage tourism were relatively unsuccessful in this case. Potential problems with applying recreation specialization to heritage tourism are discussed and implications for future studies are explored. In addition, emerging trends in importance-performance research are applied to respondent ratings of attribute importance and satisfaction in order to provide the best possible suggestions for Bear River Heritage Area management improvements and build upon existing research. Specifically, traditional importance-performance analysis is compared to analyses that incorporate grand means, segmentation, and confidence intervals.
194

Opinions of Logan City Residents Towards the Bear River District Health Departments

Borrowman, Darrell R. 01 May 1976 (has links)
The purpose of t his study was to determine the opinions and perceptions of the residents of Logan , Utah, concerning the role and responsibilities of the Bear River District Health Department , and whether those opinions and perceptions differed among low, middle and high income families; among residents having a high school degree or less, a bachelor's degree or less, or a graduate degree o r less; and among men and women. A survey instrument was administered to a stratified random sample of 150 residents. The data collected indicated that: (1) the majority of the resident s of Logan , Utah, we re not aware of the functions and services of t he Bear River District Health Department. This level of awareness was inversely proportional to income level, (2) the majority of residents of Logan, Utah, felt that the Bear River District Health Department was fulfilling it 's role and responsibilities to the community, and (3) the majority of residents of Logan, Utah, do not utilize the services of the Bear River District Health Department to meet their health needs, but rely on some other agency or professional to meet those needs . This tendency was directly proportional to income level, with low income residents relying on the health department for services to a greater degree than high income residents.
195

An Ecological/Life History Comparison of Two Whitefish Species in Bear Lake, Utah/Idaho

Thompson, Brett W. 01 May 2003 (has links)
Ecological traits of the endemic Bear Lake whitefish Prosoopium abyssicola and the Bonneville whitefish prosopium silonotus were investigated. Spatial distributions indicated distinctive differences in depth contour preference. Catch per unit effort data indicated that Bonneville whitefish prefer shallow depths and warmer water temperatures, whereas Bear Lake whitefish prefer deep, cold water. Diet differences between the two species were large. Differences in both age distribution and growth rate patterns were also observed. The Bonneville whitefish population was predominantly composed of juvenile age classes. Very large adults reached ages of 12-14 years. Bear Lake whitefish exhibited a different population structure with few young fish and larger proportions of older age classes. Some of these fish were aged over 35 years old. Both analyses suggest that the population structure of each species is the result of a stable or growing population.
196

Seasonal Variation in the Species Composition, Abundance, and Size-Frequency Distribution of Zooplankton in Bear Lake, Utah-Idaho

Moreno, Edmundo G. 01 May 1989 (has links)
Bear Lake, a large oligotrophic lake (282 km2), was studied from October 1986 to December 1987 to determine the temporal changes in the zooplankton assemblage at one site in the pelagic zone and one in the littoral area. In this study, species composition, abundance, biomass, and size frequency distribution were determined. Additionally, chlorophyll a, water transparency, and temperature and oxygen profiles were measured to help interpret zooplankton changes during the study. The zooplankton species assemblage comprised eight species of cladocera, seven species of copepods, and five species of rotifers. The abundance and biomass of the zooplankton assemblage, particularly that of crustaceans, were very low and comparable with those of oligotrophic systems. Mean densities of crustaceans in the pelagic zone, excluding copepod nauplii, varied from 250 to 1,700 organisms/m3. The analysis of the size structure of the zooplankton indicated the dominance of small organisms and the scarcity of large organisms, particularly cladocera. The zooplankton assemblage in the littoral zone was similar in species composition, abundance, and size structure to that in the pelagic zone. Many results suggest the littoral zooplankton assemblage is an extension of the pelagic assemblage. Low zooplankton food resources and interference of calcium carbonate particles in the feeding behavior of crustaceans are suggested as the primary factors controlling the low abundance and biomass of zooplankton in Bear Lake. Size-selective fish predation probably causes the assemblage to be dominated by small species. The analysis of Epischura nevadensis, the dominant species in the system, indicated that this species is bivoltine in Bear Lake. In the spring and summer, adult E. nevadensis were more abundant in the littoral zone, whereas copepodites were more abundant offshore. The low density, biomass, and small size structure of the zooplankton in Bear Lake limits its importance as a source of food for fishes.
197

Breeding Biology and Pesticide-PCB Contamination of Western Grebe at Bear River Migratory Bird Refuge

Lindvall, Mark L. 01 May 1976 (has links)
The breeding biology of western grebe was studied at Bear River Migratory Bird Refuge, Utah in 1973 and 1974. More than 300 nests were located and data gathered on nesting habitat and success. Western grebe at Bear River selected nest sites for nearness to open water of approximately 30 em in depth. At least one young was hatching in 21 percent of the nests. Avian predation and abandonment of nests following drops in water levels caused the greatest loss of nests. Chlorinated hydrocarbons monitored in western grebes showed DDE, DDD, PCB, 1260, and PCB 1254 levels in 24 breast muscle samples (wet weight) to average 12. 8, 0. 8, 3. 8, and 3. 5 ppm respectively. Contaminant concentration was found to be correlated to the condition of the bird as determined by visceral fat content. A significant (p<. 01) 2. 3 percent decline in western grebe eggshell thickness between preand post-DDT use periods was found. DDE was significantly (p<. 05) negatively correlated with eggshell thickness in western grebe. Contaminants were not linked to any reproductive failure in western grebe at Bear River MBR.
198

Morphometric Evaluation of the Whitefish Complex in Bear Lake, Utah/Idaho

Ward, Alan 01 May 2001 (has links)
Whitefish populations around the world have long been difficult to categorize taxonomically. The whitefish of Bear Lake, Utah/Idaho are no exception. There are three recognized species of Prosopium that are endemic to the lake. Two of these species, Prosopium spilonotus and Prosopium abyssicota, have previously been indistinguishable outside of spawning times. Previous studies have proposed additional taxa within P. spi/onotus to further complicate the identification among these taxa. Morphological characteristics were quantified on wild whitefish from Bear Lake, as well as from progeny reared in the laboratory from the wild adult fish. The purported taxa were separated in the field using the best characteristics presented in previous studies, and the progeny were reared separately in these groups. Otolith aging was also done on the wild adult fish to understand the age structure of the spawning populations. Results from otolith aging and morphological analyses on the laboratoryreared fish indicated that there is only one taxonomic group of P. spilonotus. By using scale counts, it was determined that P. spilonotus and P. abyssicola can be distinguished from each other with considerable reliability.
199

Integrating Black Bear Behavior, Spatial Ecology, and Population Dynamics in a Human-Dominated Landscape: Implications for Management

Raithel, Jarod D. 01 August 2017 (has links)
The New Jersey Division of Fish and Wildlife (NJDFW), in collaboration with Bear Trust International, presented us an opportunity to examine a long-term (33 years) American black bear (Ursus americanus) data set from northwestern New Jersey (NJ), USA. State agencies continue to grapple with uncertainty about the efficacy of socially divisive management actions such as recreational harvest and lethal control as tools to reduce escalating human-bear conflicts. We applied multistate capture-reencounter models to a large sample of black bear captures (>5,000) and dead recoveries (>1,300) between 1981 – 2014 to estimate cause-specific mortality and spatial dynamics between wildland and anthropogenic habitats. Additionally, we assessed temporal correlations between more than 26,500 reported human–black bear interactions and mortality rates. Adult females were twice as likely (0.163 ± 0.014) as males (0.087 ± 0.012) to be harvested, and cubs (0.444 ± 0.025) and yearlings (0.372 ± 0.022) had a high probability of dying, primarily from vehicle strikes. Nuisance behaviors reported declined with increasing harvest and lethal management (P = 0.028, R2 = 0.338). Adult bears previously designated as a nuisance and/or threat (hereafter, “problem”) were more likely to be harvested (0.176 ± 0.025) than those with no conflict history (0.109 ± 0.010). Combined legal kills and vehicle strikes, the two greatest mortality causes for marked bears, occurred significantly less than expected per unit area in urban and agricultural areas, and more than expected in the wildland-urban interface and wildland habitats. Across all age-classes, problem bears were significantly more likely to transition to anthropogenic habitats, yet they died at lower rates than conspecifics with no history of conflict in wildlands. Cubs and yearlings died at significantly higher rates than adults in the risky interface habitat, corroborating independent estimates of their increased susceptibility to harvest and vehicle strikes. Ultimately, wildland habitats represented a population source (λ = 1.133) and anthropogenic habitats a sink (λ = 0.945). Harvest represents an important management tool to help meet population targets and decrease human-bear conflicts by disproportionately removing problem bears.
200

Woodland caribou conservation in the Little Smoky: wolf management and the role of bears

Robichaud, Christine B 11 1900 (has links)
Woodland caribou population declines in west-central Alberta precipitated a wolfcontrol. This program to protect caribou could be compromised if (1) there are strong public pressures against helicopter gunning and strychnine poisoning of wolves and/or (2) other predators compensate to kill caribou. Because bears can be important ungulate predators, I used stable isotope techniques to reconstruct black and grizzly bear diets including contributions of caribou, caribou calves, ants, ungulates (moose, deer and elk), and 3 plant groups. Bears assimilated 2-58% terrestrial protein indicating large variation among individuals. As an alternative to current wolf-control practices, I reviewed spatial and temporal patterns of harvests (1985-2006) on registered traplines. Wolf trapping has increased during the past 2 decades, but on average trappers harvested only 10% of the provincial wolf population, well below culls required to control the population. Under the registered trapline system it is unlikely that trapping could control wolf abundance. / Ecology

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