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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.
111

Vertical spread rate and intesification of dwarf mistletoe in western hemlock

Richardson, Kenneth Stanley January 1970 (has links)
The vertical rate of spread of dwarf mistletoe was studied in two actively growing, young hemlock stands. This was done by determining the height and age of successive oldest and highest female infections. The rate of spread was calculated by dividing the sum of the heights of advances by the total number of years lapse between successive advances. The mean vertical spread rate was 2.1 ± 0.1 ft./yr. in a relatively open stand and 1.0 ± 0.1 ft./yr. in a relatively dense stand. The mean rate of tree growth during the maximum growth phase in the open stand was 2.5 ft./yr. and for the dense stand 1.5 ft./yr. However, over the past 25 years, the growth rate of the trees in the open stand was 1.9 ft./yr. and for the dense stand 1.1 ft./yr. The number of new infections per year increased geometrically, doubling every four years in both the dense and open stands. However, the geometric increase levelled off six years ago in the open stand and five years ago in the dense stand. During the maximum growth phase of hemlock in an open and dense stand, the most photosynthetically active upper portion of the crown remains free of mistletoe infection. Until the senescent phase is reached, the trees can be expected to outgrow the mistletoe and intensification will be restricted to the lower portions of the crowns. It is tentatively concluded that provided there is no overstory seed source and no disruption of the natural stand, such as thinning, dwarf mistletoe on hemlock will not become serious until the rate of height growth of the trees falls below the rate of vertical spread, i.e., not until after the presently accepted rotation age. / Forestry, Faculty of / Graduate
112

A model to predict pig growth based on Western Canadian production conditions

Dyble, David Leslie January 1990 (has links)
An integrated pig growth model specific to the dietary formulations, genetic quality and environmental conditions of western Canada has been developed. A computer program was designed to simulate growth of pigs between 20 kgs and 100 kgs live weight. A spreadsheet format -Lotus 123 - was used to allow programming steps to be understood by all users, including those who do not possess a high degree of programming skill. A linear programming system was also incorporated through the use of an algorithm - Optimal Solutions. A useful method of avoiding circular errors, through an initial prediction of growth, was developed through the use of a 'Gompertz' style equation which describes growth; B.W. = A exp (-B exp (-k(t))) where B.W. is body weight (kg), A is mature body weight [estimate based on NRC(1988):164 kg], B is a rate constant [4.46], k is a rate constant [range from 0.01 to 0.015] and t is the time in days. A model of nutrient flow was developed with components which include, [1] body composition at the start of growth, [2] energy and amino acid intake, [3] the utilization of ingested amino acids, [4] the upper limit to daily protein retention, [5] The interaction between metabolizable energy and protein as a proportion of the deposition of body lipid and protein, and [6] equations which assist in the prediction of performance factors. A model proof was undertaken through a study of pig performance across 4 diets varying in protein level. Pig performance indicators included; feed intake, feed efficiency, carcass index and carcass yield. A significant correlation (p<0.05) was shown between model predictions of market age and trial results. Pig rearing conditions differ in western Canada, compared to the rest of North America, due to the influence of British breeding companies and the common use of barley as a key ingredient of swine diets. The growth model developed was found to be a good predictor of performance of pigs being grown in western Canada. Feed intake and the genetic potential for protein deposition were found to be the most important predictors of pig performance. / Land and Food Systems, Faculty of / Graduate
113

Western spruce budworm : behavior and monitoring with sex-pheromone traps

Sweeney, Jonathan David January 1987 (has links)
The main objectives of this thesis were to: determine the roles of the minor components, 89/11 (E/Z⁰) 1 1-tetradecenyl acetate (AC) and 85/15 (E/Z) 11-tetradecenol (OH), of the sex pheromone of the western spruce budworm, Choristoneura occidentalis Freeman, in the orientation and pre-copulatory behaviors of the male moth; and, to evaluate various combinations of pheromone concentration, trap design, and maintenance regime for monitoring the budworm. The behavior of the male moths was observed, in a wind tunnel and in the field, in response to virgin females and to synthetic sex pheromone components, alone and in blends. The pheromones were incorporated into polyvinyl chloride rods at concentrations from 0.00005-0.5% (w:w) and release rates were estimated by gas-liquid chromatography of volatiles captured on Porapak-Q. OH contamination in lures of the major component, 92/8 (E/Z)-11-tetradecenal (ALD), and the AC, made it impossible to determine precisely the effects of either AC, ALD, or ALD+AC on the behavior of the male moth, but still allowed the testing of blends of ALD+AC+OH which resembled those released by virgin females. The moths were from three sources: a long-established non-diapausing laboratory colony; wild budworms collected near Ashcroft, B.C.; and crosses between laboratory males and wild females (lab-wild). The threshold concentration of ALD necessary to stimulate upwind flight was between 0.0005 and 0.005%; response peaked at 0.05% and dropped off above this concentration. The net upwind ground speed of flight decreased significantly at higher concentrations of ALD in the laboratory moths, and as the moths approached the lure with all three populations. In most experiments, the virgin female stimulated a greater percentage of males to contact the lure, and a faster upwind net ground speed of flight, than did ALD at about the same release rate. AC and OH stimulated response on an electroantennogram, but by themselves were not attractive to males in the wind tunnel. The addition of OH to 0.05% ALD significantly decreased the percentages of males locking-on (0.5% OH) and flying upwind (0.005% OH) in wild and lab-wild moths respectively, and significantly increased the percentage copulatory attempts of lab-wild males (0.005% OH). In the lab-wild males, a blend of ALD+AC+OH approximating that from a virgin female significantly increased the percentages of upwind flights, lure contacts, and copulatory attempts over those to ALD alone. The total blend, and not just the major component, affected long range behavior of the male moth. The laboratory males appeared less sensitive to the addition of minor components to 0.05% ALD than did the wild or lab-wild males. The mean total season's catch/plot in five non-maintained Uni-traps, baited with 0.05% ALD, was significantly correlated with the number of larvae/m² foliage in the same generation (r = 0.97), but only when a lower valley plot with very low larval density was excluded (plot 12). Correlations were significant (P ≤ 0.10) between larval density/plot in 1985 and the total moth catch/plot (n = 1 trap/plot) in 1984 in sticky traps (r = 0.45) and Uni-traps (r = 0.44) baited with 0.05% ALD and maintained. The latter correlation was significantly improved (r = 0.67; ≤ 0.05) when plot 12 was excluded. The addition of plot basal area/ha or foliage biomass/ha as independent variables significantly improved the coefficient of determination for the regression of larval density/plot in 1985 vs total seasons catch/plot in 1984, but again only when plot 12 was excluded. Of the trap systems evaluated, the Uni-trap, baited with 0.05% ALD, showed the most promise for monitoring the western spruce budworm, but permanent sample plots will have to be established and followed for several years to determine whether the system can be operational. / Forestry, Faculty of / Graduate
114

Regional, provenance and family variation in cold hardiness of western white pine (Pinus monticola Dougl. ex. D. Don)

Thomas, Barbara R. January 1990 (has links)
Thirty-seven seedlots of western white pine (Pi nus mont i col a Doug. ex. D. Don) were tested for frost hardiness to determine how transferable seed would be from different seed sources within white pine's coast and interior ranges in British Columbia. Twenty-nine seedlots represented the coast and interior of British Columbia (BC), two were from coastal United States (US), three were from interior US and three were hybrids between interior US and interior BC parents. Detached needles were exposed to a series of freezing temperatures in a programable freezer and relative hardiness was calculated as the length of injured needle expressed as a percentage of total needle length 10 days after freezing. Seasonal progress in hardening was tested using five dates in the autumn of 1989. Seedlings were maintained at the University of British Columbia nursery. Testing also was carried out from samples collected on separate dates from Nakusp in the BC interior and from Ladysmith, a coastal BC site. There was a statistically significant (p<0.0l) regional difference between the BC coast and BC interior sources in all test runs, excluding the first UBC run and the Ladysmith run. In the runs where regions differed significantly, the difference in percent damage response of needles to freezing was approximately 20%. Measurements of shoot growth phenology were planned as an additional component of growth rhythm. Injury from uncontrolled freezing forced a change of objective to evaluation of genetic differences in recovery from freezing. Those evaluations did not reveal genetic differences in recovery. / Forestry, Faculty of / Graduate
115

The culture of weeds in Western Canada, 1800-1950 : an environmental history

Evans, Clinton Lorne 11 1900 (has links)
This study chronicles the course of an important but little known Canadian war: the war between people and weeds in Western Canada. Arising from intense competition between two groups of immigrants, this conflict started in Europe, spread to Eastern North America and reached a climax on the broad expanses of the Canadian Prairies. By the early 1940s weeds had gained the upper hand on their human competitors and many predicted the end to extensive grain production in the West. This did not occur, however, because of the timely development of 2,4-D and other selective herbicides immediately following the close of World War II. These potent chemical weapons gave prairie farmers new hope at a time when defeat seemed all but certain and they are largely responsible for the expensive standoff between farmers and weeds that persists to this day. Recounting the history of weeds and weed control in Western Canada between 1800 and 1950 serves a number of functions. One is to provide weed scientists with some historical background and an object lesson in the consequences of seeking simple solutions to complex, long-standing problems. Another is to remind historians that we cannot truly understand the history of western settlement and agriculture without understanding the practical issues that dominated the daily lives of past generations of farmers. Yet a third function is to introduce a specific environmental history approach to Canadian historians while, at the same time, encouraging them to pay more attention to recent developments in this American-dominated field. A fourth and final reason for investigating the historical relationship between people and weeds is that it can be used to symbolize something far larger: the relationship between culture and nature in general. An exploration of this issue is made possible by the curious relationship between people and weeds, a relationship summed up by the thesis that weeds are both the the products of and participants in culture. The dissertation concludes with a discussion of recent trends in weed science and, in particular, of the merits of the "new" doctrine of weed management. Canadian historians are lectured on the danger of ignoring nature when writing about history and readers are asked to consider what the terms "nature" and "culture" mean. Do they represent discrete subjects, separate spheres of existence, a dichotomy? Or, are they just different aspects of a larger, more complex whole? / Arts, Faculty of / History, Department of / Graduate
116

Intensification and infection mortality of dwarf mistletoe in two stands of western hemlock

Wilford, Edward Harry January 1982 (has links)
The number, height and age of western hemlock dwarf mistletoe (Arceuthobium tsugense (Rosendahl) G.N. Jones) infections were recorded in two western hemlock (Tsuga heterophylla (Raf.) Sarg.) stands (44 and 130 years old) located on similar sites on the University of British Columbia Research Forest at Maple Ridge, B.C.. The rapid decrease in numbers of infections with infection age was shown to be largely due to infection mortality. The rate of intensification of the disease expressed as "doubling time" was estimated to be 40 or more years in both stands. Also estimated was a rate of vertical spread of .15 metres per year. The results differed markedly from those of other studies in similar stands, which generally predict "doubling times" of 2 to 4 years and vertical spread rates of up to .5 metres per year. / Forestry, Faculty of / Graduate
117

The Palladium (II) –Catalyzed Homogeneous Oxidation of 1-Hexene

Kirova, Margarita 01 May 1992 (has links)
The Palladium(II)-catalyzed homogeneous oxidation of 1-hexene in methanolic medium has been studied, copper(II) chloride being used as cocatalyst. Aspects of the kinetics, mechanism and product composition were investigated in several series of oxidations involving variation of hexene concentration, oxygen partial pressure, Cu(II): Pd(II) ratio and concentration and temperature. The progress of the reaction was studied in the course of periodic sampling runs. Reaction products were identified by gas chromatography, and verified by means of GC/mass spectrometry. The expected product of 1-hexene oxidation was 2-hexeanone: however, 3-hexanone occurs as a major coproduct, arising from concurrent Pd(II)-catalyzed isomerization of 1-hexene to 2-hexene. Isomerization is inhibited by excess copper(II) chloride. The overall oxidation is generally consistent with P.M. Henry’s mechanism for Pd(II)-catalyzed alkene oxidation, the rate-limiting step being the π-to σ-rearrangement of the Pd(hexane) complex. The corresponding ketals (2,2-dimethoxyhexane and 3,3-dimethoxyhexane) were also found. Free hexanal was not detected in any oxidation product mixtures; when produced it was found as the dimethyl acetal. Chlorination products were not observed. A surprisingly sharp rate maximum was observed when copper(II) chloride concentration was varied. Two kinetic regions were found to occur in virtually all oxidations. An explanation is proposed for this behavior.
118

Orientating, Developing, and Promoting an Islamic Christology

Albert, Alexander 08 March 2010 (has links)
The purpose of this study is to promote research into and the development of a non-polemical Islamic conception of Jesus Christ. Before engaging the textual sources the thesis considers in some detail the historical context within which the Quranic discourse about Christ was formulated, and then some post-Quranic Christological disputes between Muslims and Christians. It also considers a broad range of Quranic data about Christ in order to identify certain primary themes in the Quran about him. Then three Quranic verses about Christ and his relationship with the Holy Spirit are analyzed through the interpretations of four classical exegetes. On the basis of their interpretations as well as the general Quranic discourse about Christ this thesis makes a limited number of positive assertions about Christ as well as suggests areas wherein further research on the specifically Islamic view of Christ can be developed.
119

中國文藝復興

ZHOU, Benzhen 08 June 1937 (has links)
No description available.
120

Wright Morris: The man and his books

Unknown Date (has links)
"The purpose of this paper is to present information about the life and works of Wright Morris, a contemporary American writer, to indicate some of the principal characteristics of his books, and to show evidence of their acceptance by critical reviews. He is the author of eleven books, the first of which was published in 1942; since then he has gained recognition steadily as one of the outstanding novelists in this country today"--Introduction. / Typescript. / "August, 1958." / "Submitted to the Graduate Council of Florida State University in partial fulfillment of the requirements for the degree of Master of Science." / Advisor: Sara K. Srygley, Professor Directing Paper. / Includes bibliographical references (leaves 74-82).

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