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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.
11

Nest parasitism in red-breasted mergansers (Mergus serrator) in New Brunswick

Janishevski, Lisa. January 2000 (has links)
No description available.
12

Territorial defense and mate attraction in isolated and social white-breasted nuthatches (Sitta carolinensis): tests of stochastic dynamic programming models

Elliott, Jennifer Theresa 09 March 2005 (has links)
No description available.
13

Conservation status of buff-breasted sandpipers (Tryngites subruficollis) in the Western Hemisphere: a conservation genetic approach

Lounsberry, Zachary T. January 1900 (has links)
Master of Science / Division of Biology / Samantha M. Wisely / Range-wide estimates of shorebird (Aves: Charadriiformes) populations suggest sharp declines in population sizes across a range of species. Efforts to accurately assess the conservation status of wild populations are becoming increasingly vital to species management. One shorebird of conservation concern, the Buff-breasted Sandpiper (Tryngites subruficollis), is a New World migrant which winters in southeastern South America and breeds in the arctic. To establish an updated conservation status for Buff-breasted Sandpipers, we conducted a molecular survey of wild populations on spatial and temporal scales. We analyzed patterns of global population structure, demographic trends, and phylogeography using nine polymorphic microsatellites and two mitochondrial DNA (mtDNA) markers, cytochrome b and the control region, among 477 individuals across their distributional range. To empirically assess the impact of population declines on genetic diversity, we also surveyed segments of the same two mtDNA markers from 220 museum specimens collected across a 135-year period. Contemporary microsatellite and mtDNA analyses revealed that Buff-breasted Sandpipers are admixed on a global scale, with effective population size estimates ranging from 2,657 to 16,400 birds and no signal of a recent genetic bottleneck. Contemporary mtDNA analyses suggested a pattern of haplotype diversity consistent with a historic radiation from a single refugium which we estimated to have occurred between 8,000−45,000 years before present. Using five measures of mtDNA diversity (haplotype and nucleotide diversity, trend analyses of haplotype richness, Watterson’s estimate of theta, and phi-statistics), as well as a Bayesian Skyline reconstruction of demographic trends in effective population size (N[subscript]e[subscript]f), we concluded that substantial mtDNA diversity and N[subscript]e[subscript]f had not been lost as a result of the population declines in this species. While genetic diversity did not appear to have been lost due to population losses, management efforts must focus on preventing future losses in order for wild populations to remain viable. Our results suggested that the global population of Buff-breasted Sandpipers should be treated as a single, panmictic conservation unit and that successful management must focus on preventing further declines and habitat fragmentation.
14

Habitat selection in the yellow-breasted chat

January 1979 (has links)
M. S.
15

Habitat selection in the yellow-breasted chat

McQuate, Grant Thomas January 1979 (has links)
During the spring and early summer of 1978, boundaries were determined for 19 yellow-breasted chat (<i>Icteria virens</i>) territories in southwestern Virginia. The gross structural characteristics of the vegetation found within these areas were analyzed. Each vegetation variable was regressed against territory size and against a measure of chat density. It was assumed that both smaller territories and territories having a greater number of territories surrounding them contained better quality habitat. Chats appear to choose their habitat on the basis of the total brushiness present. of several different components. This value may result from the summation In this study, bramble (<i>Rubus</i> spp.) cover and total shrub cover were the two major components involved. The vegetation contributing to the total brushiness value should minimally provide about 25% cover and average about 0.75 min height. Increased greenbrier (<i>Smilax</i> spp.) cover is associated with better quality chat habitat. Presumably, it is indicative of the types of vegetation, such as thickets and open woods, which are characteristic of chat habitats. However, the measure of greenbrier cover seems limited in its ability to distinguish preferred chat habitat. Chat territories may include wooded areas provided there is a fairly dense growth of vegetation below about 1.5 m. Generally, this situation would occur only in a woods with a reasonably open canopy. If only an edge of a woods bordering a brushy field is involved, side-lighting may be sufficient for the growth of ground-level vegetation, even if under fairly dense overstory vegetation. / M. S.
16

The effect of bra size correction on selected postural parameter

Mthabela, Nosipho Pearl January 2015 (has links)
Submitted in partial compliance with the requirements for the Master's Degree in Technology : Chiropractic, Durban University of Technology, Durban, South Africa, 2015. / Introduction: Symptoms associated with large breasts result from bra strap chafing, poor body posture, headaches, neck, shoulder, thoracic and lower back pain. There is a paucity of literature quantifying objective data regarding the effect of breast size on posture. Therefore correct bra sizing may improve posture, however this is undetermined. This study aimed to investigate the effect of bra correction on selected postural parameters in order to determine its relevance in a clinical setting. Methodology: Sixty five females who met the inclusion criteria had the following parameters recorded: age, height, weight, body mass index, occupation, and underbust and overbust bra size. An anterior-posterior, right and left lateral digital photographs were taken before and after bra correction. These were then processed using the Posture Pro software. The data was analysed using the latest version of SPSS. The results were presented by means of standard deviations and ranges and differences between pre and post measures were performed with an ANOVA. Results: It was found that there was no correlation between changes in any of the four parameters from pre to post correction, which changed significantly with postural correction (4/43 post correction significant readings) and the demographic variables. Most participants changed to a larger cup sizes after correction which is in line with Greenbaum, (2003) who found that participants tend to buy a smaller bra size. In this study 3% of the study population changed to a bigger cup size and 97% wore bras that were too tight. Similar to the findings of Wood eta/., (2008) who found that 70% of the study population wore bras that are too small and 10% wore bras that were too big. Conclusion: In the study on effect of incorrect bra size on selected postural parameters it was found the there were four parameters that changed significantly with p<O, 05 [ANOVA]. Further investigation needs to be done on a larger sample size, age group range, BMI and different demographic. / PDF copy unavailable. please refer to hard copy for full text information / M
17

White-breasted nuthatch density and nesting ecology in oak woodlands of the Willamette Valley, Oregon

Viste-Sparkman, Karen 30 January 2006 (has links)
Graduation date: 2006 / Habitat loss causes a reduction in available resources for wildlife, alters the configuration of remaining habitat, and may isolate wildlife populations. White-breasted nuthatches (Sitta carolinensis) are experiencing long-term population declines in the Willamette Valley of Oregon, where they are historically associated with oak woodlands. As secondary cavity-nesters, white-breasted nuthatches may be limited by the availability of existing cavities for nesting and roosting. Oak vegetation in the Willamette Valley has changed since European-American settlement times from vast areas of open oak savanna to isolated closed-canopy stands separated by agricultural fields. We examined nuthatch density, nest cavity selection, and nest success in relation to oak woodland structure and landscape context. We conducted point transect surveys in 3 strata: woodland interiors, large woodland edges, and small woodlands. We located and monitored nuthatch nests and sampled vegetation at nest locations and matching random locations around each nest. Woodland structure and edge density were measured at a 178-m radius (home range) scale, and landscape context was measured using vegetation cover within a 1-km radius around point transects and nests. We used program DISTANCE to fit detection functions and calculate nuthatch densities. We used conditional logistic regression to compare nest locations with random locations, and analyzed nest success with Mayfield logistic regression. White-breasted nuthatch density was significantly higher in small woodlands than in edges of large woodlands, which had higher nuthatch density than woodland interiors. Density of nuthatches increased with a combination of oak cover within a 1-km radius of the point, edge density within a 178-m radius, and number of oak trees >50 cm diameter at breast height (dbh) within a 100-m radius. Nest cavities were situated in oak trees containing more cavities than random oak trees that had cavities, and oak trees used as nest trees had a larger dbh than oak trees within random plots. Local woodland structure at nest locations was characterized by larger trees, measured by greater mean dbh, canopy cover, and basal area of oaks than random locations within the home range. Nest success in natural cavities was 71% and was not predicted by attributes of nest cavities, nest trees, local woodland structure at nests, woodland structure at the home range scale, or landscape context. These results suggest that the most suitable habitat for white-breasted nuthatches in the Willamette Valley includes oak woodlands in close proximity to one another with a high proportion of edge and mature oak trees. Managers should preserve trees containing cavities and large oak trees whenever possible. Thinning of small oaks and removal of conifers in oak woodlands to create more open, savanna-like conditions may also promote the development of larger oaks with more spreading branches, providing more opportunities for cavities to form and more foraging surface area for nuthatches.
18

The response of bark-gleaning birds and their prey to thinning and prescribed fire in eastside pine forests in Northern California /

Rall, Christopher James. January 1900 (has links)
Thesis (M.S.)--Humboldt State University, 2006. / Includes bibliographical references (leaves 91-97). Also available via Humboldt Digital Scholar.

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