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Theses/Dissertations

1986

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Articles 31 - 60 of 175

Full-Text Articles in Life Sciences

Determination Of Human Sperm Cell Acrosin Activity From Normal And Subfertile Men, Dilrowshan H. Haque Jul 1986

Determination Of Human Sperm Cell Acrosin Activity From Normal And Subfertile Men, Dilrowshan H. Haque

Chemistry & Biochemistry Theses & Dissertations

Acrosin is an acrosomal enzyme which is reported to be involved in sperm penetration through cumulus, zona, and ooplasma. This enzyme has been reported to be significantly lower in sperm of infertile men compared to sperm of fertile men. The acrosin assay which has been developed can be used for studies in patients with suspected infertility and may be used on a fraction of most semen specimens being evaluated in a clinical andrology laboratory.

Within-run precision studies yielded coefficients of variation of 11% for a low-activity pool and 9% for normalactivity pool specimens. Between-run precision studies using a single donor …


A Histological Investigation Of The Larval Mandibular Organ In The Mud Crab Rhithropanopeus Harrisii (Gould) (Crustacea Decapoda Xanthidae), Lore Lynn Hantske Jul 1986

A Histological Investigation Of The Larval Mandibular Organ In The Mud Crab Rhithropanopeus Harrisii (Gould) (Crustacea Decapoda Xanthidae), Lore Lynn Hantske

OES Theses and Dissertations

Mandibular organs of the mud crab, Rhithropanopeus harrisii (Gould) were histologically located and followed throughout the larval cycle to determine their role in metamorphosis. Specimens from each day of the four larval stages and the megalopa stage were embedded in paraffin, sectioned at 8 μm, stained and observed under the microscope for the mandibular organs. The organs were located in the mandibular area of second, third and fourth stage larvae. The organs were probably present in the first stage zoeae and in the megalopa stage, although the

techniques of the study were not sensitive enough to observe them. The …


The Decline Of Log House Construction In Blount County, Tennessee, John T. Morgan Jun 1986

The Decline Of Log House Construction In Blount County, Tennessee, John T. Morgan

Doctoral Dissertations

The log house is an important element of architectural heritage of much of the eastern United States. In some areas, such as East Tennessee, log construction was not replaced by frame construction until the late nineteenth century.

Several reasons have been presented in the literature for the decline of log house construction, but none of them had been tested empirically. This study determined to what extent the reasons given for the decline of the log house construction explain the decline of log dwelling construction in Blount County, Tennessee. The study analyzed the influence of five factors: (1) relative affluence of …


Between Population Comparison Of Resource Acquisition In The Long Jawed Orb Weaving Spider Tetragnatha Elongata, Rosemary Grace Gillespie Jun 1986

Between Population Comparison Of Resource Acquisition In The Long Jawed Orb Weaving Spider Tetragnatha Elongata, Rosemary Grace Gillespie

Doctoral Dissertations

Behavioral adaptations for resource acquisition in the long jawed orb weaving spider Tetragnatha elongata Walckenaer (Araneae: Tetragnathidae) are documented in this study. It examines the form and mechanism of spider foraging behavior, an essential prerequisite to the realization of the commercial use of spiders in integrated pes t management. Being the most common and ubiquitous of insect predators, spiders offer tremendous potential as stabilizers in agro ecosystems with unstable cycling of phytophagous insects. The initial part of this study examines the mechanisms employed by T. elongata in selecting a habitat, and demonstrates that spiders do not build webs where the …


Dietary Cholesterol, Tissue Phospholipids And Prostacylin Production Of Rat Aorta, Mieko Hoshino Andress Jun 1986

Dietary Cholesterol, Tissue Phospholipids And Prostacylin Production Of Rat Aorta, Mieko Hoshino Andress

Loma Linda University Electronic Theses, Dissertations & Projects

Male Sprague-Dawley weanling rats were divided into three groups, a control (rat-chow and 5% corn oil), the control diet plus cholesterol, and the control diet plus both cholesterol and cholic acid. After four months the animals were sacrificed and blood samples, along with abdominal and thoracic aorta cross-sectional ring segments. were collected. The serum cholesterol levels, fatty acid compositions in the phospholipids (PL) of the aortic tissues (thoracic and abdominal aorta tissues combined), and the endogenous 6-keto-PGFla (stable metabolite of PGI2) production in thoracic and abdominal aortic tissues were While serum cholesterol levels were highest in the rats fed a …


Effects Of Lateral Mandibular Expansion On Mandibular Morphology In The Growing Rat : A Comparative Study Of Treatment Effects With Orthopaedic And/Or Surgical Procedures, Eric Looi Jun 1986

Effects Of Lateral Mandibular Expansion On Mandibular Morphology In The Growing Rat : A Comparative Study Of Treatment Effects With Orthopaedic And/Or Surgical Procedures, Eric Looi

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study was to investigate the effects of mandibular expansion by orthopaedic and surgical procedures in the growing rat mandible.

Sixty-four 35 day old Sprague Dawley Harlan rats were divided into four groups of 16 rats each and categorized as the control, orthopaedic expansion, surgery without graft and surgery with graft respectively. Prefabricated appliances were used for orthopaedic expansion of the mandibles and maintaining surgical expansion at the symphysis in the respective groups. Oxytetracycline were given intraperitoneally to mark areas of bone remodeling. Half the number of rats from each group were sacrificed at the end of …


The Development Of Smallholder Tea Production In Tanzania: An Economic Analysis Of Factors Influencing Green Leaf Tea Output, Joseph Tarmo Nagu Jun 1986

The Development Of Smallholder Tea Production In Tanzania: An Economic Analysis Of Factors Influencing Green Leaf Tea Output, Joseph Tarmo Nagu

Doctoral Dissertations

This study focused on smallholder tea production as one strategy for Tanzanian economic development. The central research question was the economic evaluation of the potential of this strategy for increasing peasant farmer income streams in an economy comprised of mostly subsistence farming.

Two objectives were: (1) the assessment of the extent to which selected production factors explain the variability in the annual output of green tea leaf (output) and (2) the estimation of the physical resource productivities and the computation of marginal value products (MVP's) of selected resources for a sample 150 smallholder tea farms in Njombe, Tanzania to determine …


Factors Affecting Epithecal Growth Lines In Four Coral Species, With Paleontological Implications, Jean-Luc Liénard Jun 1986

Factors Affecting Epithecal Growth Lines In Four Coral Species, With Paleontological Implications, Jean-Luc Liénard

Loma Linda University Electronic Theses, Dissertations & Projects

The number of epithecal (external) growth lines was surveyed over 124 days for Montastrea annularis growing at different depths (3.5 m to 61 m). There was a significant (P< .01) decrease in the number of lines with depth. Although the linear regression is significant, there is evidence for a logarithmic or quadratic relationship, and more data from greater depths are needed to determine which of these gives a better fit.

The number of growth lines formed during light-dark cycles of 16, 24 and 32 hours were compared for M. annularis, M. cavernosa, Porites astreoides and Tubastrea aurea. The variability among colonies from the same species was in many cases more significant than that among light treatments. This is a serious problem for anyone counting lines in corals, especially from a few specimens; therefore conclusions based on such counts seem hazardous on …


Industrial Development Bonds In Knox County, Tennessee: An Analysis Of Their Impact On The Local Community, Timothy L. Leasure Jun 1986

Industrial Development Bonds In Knox County, Tennessee: An Analysis Of Their Impact On The Local Community, Timothy L. Leasure

Masters Theses

The purpose of this study was to create a methodology local governments could use in determining the impact of industrial development bonds on the local community. The areas of impact studied were water and sewer infrastructures and the cost of providing the services, highway capacities, property tax generation, and employment generation. Knox County, Tennessee was chosen as a general study area because of the interest local officials had in this topic and because data was readily accessible.

A cost/benefit analysis of the provision of water and sewer services, and impact analyses on infrastructure capacities, the property tax base and the …


The Effects Of Strain Differences On The Binding Of Concavalian A To Mouse Sperm, Lisa A. Mckay Jun 1986

The Effects Of Strain Differences On The Binding Of Concavalian A To Mouse Sperm, Lisa A. Mckay

Honors Theses

The current study, lectins were used as genetic probes to determine the phenotype of the sperm from different strains of mice. Lectins are proteins of non-immune origin, which bind to specific carbohydrates (McCoy, 1986). Being that virtually all cell membranes contain carbohydrate components, lectins have been used to identify all types of cells. In this study, a biotinylated lectin Concavalian A (Con A) derived from Canavalia ensiformis, was used and binding was detected using an avidin-biotin peroxidase (ABP) complex technique. The object of the current research was to 1) determine if mouse strain differences have an effect on lectin binding, …


An Immunochemical Analysis Of Alcoholic Hyaline And Its Relationship To Keratin Intermediate Filaments, David L. Drexler Jun 1986

An Immunochemical Analysis Of Alcoholic Hyaline And Its Relationship To Keratin Intermediate Filaments, David L. Drexler

Loma Linda University Electronic Theses, Dissertations & Projects

Alcoholic Hyaline (AH) and keratin intermediate filaments possess ultrastructural, biochemical and immunochemical similarities. This study compares human AH, human stratum corneum keratin (HSCK) and normal human liver cytokeratin (HCK) by quantitative immunochemical means, using polyclonal as well as monoclonal antibodies. Enzyme-linked immunosorbent assays (ELISAs) were employed, as well as "immunoblotting" and immunocytochemical techniques. HCK was isolated using Triton X-100 and "high-salt” buffers and exhibited seven major polypeptide bands on SDS-PAGE (41-58 kd). Antisera were made toward HCK and the two major HCK bands. Other immunochemicals included antisera toward AH, the three major AH bands, and HSCK, as well as 3 …


The Parotid Salivary Glands. I. Potential Role Of A Parotid Factor Modulating Pancreatic Β-Cell Function. Ii. An Immunohistological Study To Identify Parotid Hormone Secreting Cell(S), Denise S. Cook Jun 1986

The Parotid Salivary Glands. I. Potential Role Of A Parotid Factor Modulating Pancreatic Β-Cell Function. Ii. An Immunohistological Study To Identify Parotid Hormone Secreting Cell(S), Denise S. Cook

Loma Linda University Electronic Theses, Dissertations & Projects

The physiologic role of the parotid glands is more complex than its recognized salivary function. Various investigators have suggested an intriguing relationship between the parotids and the pancreas, both endocrine and exocrine in nature.

We studied in rats the contribution of salivary glands in the regulation of β-cell function in response to an acute intra-arterial glucose challenge in parotidectomized, submandibulariectomized and totally sialoadenectomized animals. Fifteen days post-parotidectomy or total sialoadenectomy, the β-cell response, at 2 minutes post-glucose infusion, diminishes and stabilizes at about 40% of the preoperative value. Concurrent with the depressed insulin secretion a correspondingly higher glucose titer was …


Augmentation Of Natural Killer Cell Activity By Corynebacterium Parvum: Involvement Of Lipoxygenase Pathway, Gregory D. Kuo Jun 1986

Augmentation Of Natural Killer Cell Activity By Corynebacterium Parvum: Involvement Of Lipoxygenase Pathway, Gregory D. Kuo

Loma Linda University Electronic Theses, Dissertations & Projects

The 51Chromium release assay was used to measure natural killer (NK) cell activity associated with Corynebacterium parvum (CP) injection against YAC-1 and MBT-2 targets. The peritoneal exudate cells from intraperitoneal treatment of CP at different dosages consistently gave higher cytotoxicity than their respective spleen cell fractions. In contrast, CP given intravenously showed the reversed effect. Our results demonstrate that the route of administration and dosage of CP are two crucial variables for determining the effectiveness of this immunostimulant. In vitro manipulations of nordihydroguaiaretic acid, indomethacin, and prostaglandin E2 on CP-stimulated NK cells suggest that the lipoxygenase pathway is involved …


Interaction Of Putative Estrogens And The Estrogen Receptor System In Leydig Cells In The Balb/C Mouse Testis Resulting In The Initiation Of Dna Synthesis, R. Lloyd Juriansz Jun 1986

Interaction Of Putative Estrogens And The Estrogen Receptor System In Leydig Cells In The Balb/C Mouse Testis Resulting In The Initiation Of Dna Synthesis, R. Lloyd Juriansz

Loma Linda University Electronic Theses, Dissertations & Projects

Continuous administration of estrogens for 7-9 months, both steroidal and nonsteroidal, to male BALB/c mice, leads to the formation of testicular Leydig cell tumors. Three days following the subcutaneous implantation of a pellet of estrogen in cholesterol, there is a peak in the incorporation of 3H-tymidine into the DNA of the interstitial cells. These effects are hypothesized to be mediated by the estrogen receptor system in the Leydig cell. Common experimental techniques for the measurement of hormone binding, such as dextran coated charcoal treatment, proved to be impossible to employ in this system, therefore a procedure was developed using …


Cooperativity Of Ligand Binding As A Function Of Monomer-Dimer Equilibrium Parameters And Acceptor Concentration, George K. Wolfer Jun 1986

Cooperativity Of Ligand Binding As A Function Of Monomer-Dimer Equilibrium Parameters And Acceptor Concentration, George K. Wolfer

Loma Linda University Electronic Theses, Dissertations & Projects

A general monomer-dimer equilibrium system involving ligand interactions is presented. Cooperativity features of specific limited models are analyzed by selecting the appropriate family of equilibrium constants from this general scheme. Each system is then characterized in terms of Hill coefficient dependency on alterations in values of equilibrium constants and total acceptor concentration. This method permits comparison of predicted cooperativity trends between systems. Contrasting reports concerning cooperativity dependencies for certain defined equilibrium systems are compared and the discrepancies resolved. Characteristics of cooperativity binding patterns are shown to include symmetry about dimerization association constant values, both positive and negative cooperativity for a …


Restriction Analysis Of Bacteriophage, Ali Reza Mostaghimi Jun 1986

Restriction Analysis Of Bacteriophage, Ali Reza Mostaghimi

Loma Linda University Electronic Theses, Dissertations & Projects

A restriction map of DNA from bacteriophage P3-C1 for the endonucleases BamH I, Bgl II, EcoR I, Hind III, Sac I and Sca I is described in this study. The phage DNA was determined to be a linear double stranded molecule with a unit genomic length of 31 kb. After electrophoresis in 0.5% agarose gels, the undigested DNA appeared as three molecules of 31, 62 and 93 kb in length. The Hind III digestion pattern of the individual 31 kb molecule was identical to the 62 kb and 93 kb Hind III pattern. With all enzymes except Hind III, …


Comparative Bioavailability Of Sediment-Sorbed Hexachlorobiphenyl, C. Michael Swindoll Jun 1986

Comparative Bioavailability Of Sediment-Sorbed Hexachlorobiphenyl, C. Michael Swindoll

Doctoral Dissertations

The bioavailability of sediment-sorbed hexachlorobiphenyl (HCB) to bacteria, midge larvae (Chironomus tentans), and mosquitofish (Gambusia affinis) was examined in order to elucidate the influence of abiotic and biotic factors on the bioaccumulation process. Factors examined included sediment type, sediment organic matter, HCB concentration, temperature, and biological viability. Additional experiments were conducted to evaluate the relative role of sediment and dietary HCB sources to the accumulation of HCB in mosquitofish.

In general, the bioavailability of sediment-sorbed HCB was inversely related to the surface area and the organic content of the sediment. The organic content of the sediment …


Characterization Of Microorganisims After Feeding With Phenolic Compounds : Comparing A Domestic Sludge To An Industrial Sludge, Dianne Adamowitz May 1986

Characterization Of Microorganisims After Feeding With Phenolic Compounds : Comparing A Domestic Sludge To An Industrial Sludge, Dianne Adamowitz

Theses

This study examined the effects of phenolic compounds on the populations in mixed liquors obtained from two very different treatment plants: the Passaic Valley Sewerage Commissioners plant in Newark, and the Livingston, NJ municipal treatment plant. The dominant organisms were identified initially and after ten days exposure to phenol (100 ppm), and either 2-chlorophenol (20 ppm) or 2,6-dichlorophenol (10 ppm) in aerated batch reactors.

Results confirmed the remarkable similarity between the two mixed liquor populations, in spite of the significant differences in the operation of the two treatment plants.


Adsorption Of Aminopyridines To Phosphatidylserine Vesicles, Colin Wright May 1986

Adsorption Of Aminopyridines To Phosphatidylserine Vesicles, Colin Wright

Dissertations and Theses

Intrinsic association constants were determined for a series of aminopyridines on phosphatidylserine vesicles, through determination of electrophoretic mobility. The magnitudes of the constants were such that depolarization of the nerve terminal through binding to negative phospholipids seems unlikely to occur. The aminopyridines all had association constants between one half and one sixtieth the association constant of calcium. The aminopyridines probably block potassium channels in their enhancement of synaptic transmission.

An interesting correlation was noted in that the ranking of the aminopyridines in terms of their affinity for these lipids was approximately the same as the ranking of their enhancement of …


Effect Of Ethanol On Thermoregulation In The Goldfish Carassius Auratus, Candace Sharon O'Connor May 1986

Effect Of Ethanol On Thermoregulation In The Goldfish Carassius Auratus, Candace Sharon O'Connor

Dissertations and Theses

In an attempt to elucidate the mechanism by which ethanol affects vertebrate thermoregulation, the effect of ethanol on temperature selection was studied in the goldfish, Carassius auratus. Ethanol was administered to 10 to 15 g fish by mixing it in the water of a temperature gradient. The dose response curve was very steep between 0.5% (v/v) ethanol (no response) and 0.7% (significant lowering of selected temperature in treated fish). Fish were exposed to concentrations of ethanol as high as 1.7%, at which concentration most experimental fish lost their ability to swim upright in the water. At concentrations higher than …


Bird Use Of Lakes In The Claremont-Upland Area, Valerie Banschbach May 1986

Bird Use Of Lakes In The Claremont-Upland Area, Valerie Banschbach

Pomona Senior Theses

I studied water bird use of two lakes in the Claremont-Upland area to determine what physical, chemical, and biological aspects of these lakes provide suitable water bird habitat and food resources. I censused the Bernard Field Station Lake in Claremont and a gravel pit freshwater area in Upland from 10/85 to 3/86 for water bird use. I also mapped these sites, noted their water surface area and water depth changes, monitored their water chemistry, and censused their vegetation. The results of this work showed more total water birds per hour of observation time, and more birds per hour of observation …


Lodgepole Pine Susceptibility Rating Of Mountain Pine Beetle Through The Use Of A Density Management Diagram, John Albert Anhold May 1986

Lodgepole Pine Susceptibility Rating Of Mountain Pine Beetle Through The Use Of A Density Management Diagram, John Albert Anhold

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Ninety-four unmanaged lodgepole pine stands were examined to evaluate the relationship between stand density and susceptibility to mountain pine beetle attack. Sample included stands from a broad geographical range in the western United States.

Beetle population trends were not significantly related to variation in stand density as measured by stand density index (SDI). The percentage of trees killed per acre by the mountain pine beetle in stands with greater than eighty percent lodgepole pine did vary significantly with changes in SDI. From these data three SDI zones were identified: 1) stands with SDI's of less than 125 showed low potential …


Impact Of The Western Spruce Budworm On Buds, Developing Cones And Seeds Of Douglas-Fir In The Intermountain Region, Charles Joseph Frank May 1986

Impact Of The Western Spruce Budworm On Buds, Developing Cones And Seeds Of Douglas-Fir In The Intermountain Region, Charles Joseph Frank

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The western spruce budworm, Choristoneura occidentalis Freeman (Lepidoptera: Tortricidae), is a serious defoliator of conifers in the western U.S. and western Canada. In 1985 epidemic levels of the budworm caused average tree defoliation in west-central Idaho to increase to 83%, up substantially from the 35% average tree defoliation of 1984. Associated with this increase in defoliation was a change in the relative stand defolation ranking between the two years. found to damage all types and In 1985 the budworm was developmental stages of reproductive structures of Douglas- fir, including: seedcone buds, pollen-cones buds, maturing cones, and seeds. Differential selection of …


Investigation Of Host Selection By Mountain Pine Beetle (Dendroctonus Ponderosae) Hopk. In Lodgepole Pine (Pinus Contorta) Dougl., Thomas James Eager May 1986

Investigation Of Host Selection By Mountain Pine Beetle (Dendroctonus Ponderosae) Hopk. In Lodgepole Pine (Pinus Contorta) Dougl., Thomas James Eager

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Lodgepole pines Pinus contorta (Douglas) were treated by girdling to assess the response by an endemic population of mountain pine beetle Dendroctonus ponderosae (Hopkins) (Coleoptera: Scolytidae). Capture in 'sticky traps' indicated that the beetles were attracted while in flight towards the wounded trees. A significant difference in the landing rates of bark beetles between the treated and untreated trees indicated that the beetles were able to distinguish wounded from non-wounded trees while still in flight. Pressure chamber readings demonstrated that water stress developed in the girded trees when compared to the non-girdled trees.


Estimating Optimum Overstory Vegetation Reduction For Increasing Understory Production, John A. Tanaka May 1986

Estimating Optimum Overstory Vegetation Reduction For Increasing Understory Production, John A. Tanaka

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this study was to investigate analytical approaches for estimating the optimum (profit maximizing) rate of initial overstory kill for increasing seasonal forage availability on a specific ranch. The models were developed using the big sagebrush (Artemisia tridentata) - crested wheatgrass (Agropyron cristatum, A. desertorum) vegetation type on a Utah cow-calf-yearling operation as an example. The models should be applicable on any ranching situation where understory forage production is constrained by the establishment and growth of undesirable overstory vegetation.

Three model forms were developed and compared for their applicability to on-the-ground investment decision …


The Effects Of Recreation Specialization And Motivations On The Environmental Setting Preferences Of Backcountry Hikers, Randy J. Virden May 1986

The Effects Of Recreation Specialization And Motivations On The Environmental Setting Preferences Of Backcountry Hikers, Randy J. Virden

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study explored how recreation specialization and different types of motivations were related to environmental settings preferred by backcountry hikers. A questionnaire was developed that measured the level of hiking specialization, desired psychological outcomes, and preferred environmental setting attributes. Questionnaires were mailed to 619 backcountry hikers from three Intermountain West hiking areas; a response rate of 68 percent was attained.

Results of the study revealed significant associations between the level of hiking specialization and the psychological states desired by backcountry hikers. In general, increased hiking specialization served to increase the importance of specific psychological outcomes such as autonomy, exercise, achievement …


Aspects Of The Feeding Ecology Of The Bonneville Cisco Of Bear Lake, Utah-Idaho, David C. Lentz May 1986

Aspects Of The Feeding Ecology Of The Bonneville Cisco Of Bear Lake, Utah-Idaho, David C. Lentz

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Bonneville cisco (Prospium gemmiferum), a small planktivorous whitefish, is an important part of the distinctive fish community of Bear Lake, Utah-Idaho. The Bonneville cisco plays a key role in the trophic structure by converting zooplankton to fish biomass and providing a major forage source for cutthroat and lake trout. Aspects of cisco feeding ecology studied include characterization of the zooplankton community composition and dynamics and cisco feeding habits and prey selection.

Composition and seasonal dynamics of the zooplankton community were determined for a fifteen month period during 1981-1982. The community was dominated by a calanoid copepod, Epischura …


Purification Of Anthrax Toxin Protective Antigen Component And Characterization Of Its Binding Interaction With Bovine Kidney Cells, Daniel Dalton Martin May 1986

Purification Of Anthrax Toxin Protective Antigen Component And Characterization Of Its Binding Interaction With Bovine Kidney Cells, Daniel Dalton Martin

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Protective antigen component of B. anthracis toxin was produced and purified to the >99% level. Toxin was purified from culture supernatant utilizing concentration and liquid chromatography techniques. Purity was determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

The purified protective antigen retained biological and antigenic activity as evidenced respectively by lethality in Fischer 344 rats when injected in combination with lethal factor, and by positive results on the Ouchterlony double diffussion assay.

Radioiodinated protective antigen was used both in the in vivo and the in vitro experiments.

In vivo distribution of labelled protective antigen was determined in Fischer 344 rats. Assay …


The Effect Of Utah Population Growth On Conversion Of Agricultural Land To Residential Land, Suzanne Shoshana Dyner May 1986

The Effect Of Utah Population Growth On Conversion Of Agricultural Land To Residential Land, Suzanne Shoshana Dyner

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Land resources are essential to the production of many goods and services, including food, fiber, housing, and recreation. Often, these alternate uses are thought to be incompatible, and the conventional wisdom holds that in a place such as Utah, where rapid population growth is occurring near farming activities, at least some agricultural land must be converted to developed uses. The purpose of this paper is to investigate the strength of the relationship between population growth and change in farmland, especially cropland, in Utah.

Theoretically, population growth has been assumed to affect the amount of land in agricultural use. An empirical …


Factors Affecting Puberty, Estrus And Ovulation In Corriedale And Criollo Sheep Of The Southern Peruvian Highlands, Pedro Walter Bravo Matheus May 1986

Factors Affecting Puberty, Estrus And Ovulation In Corriedale And Criollo Sheep Of The Southern Peruvian Highlands, Pedro Walter Bravo Matheus

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This research was conducted at the La Raya experiment station, Cusco, Peru (4200 m elevation, 15°S latitude, and 70 °W longitude) using 60 Corriedale, and 60 Criollo ewes during three consecutive years (April 1981 - March 1984). Age, and weight at puberty, age at physical maturity, and the effects of breed, age (physically immature and mature), year, and month were measured on body weight, incidence of estrus, and incidence and rate of ovulation. There was a significant difference (P<.05) among breed, year, and the interactions for body weight at puberty. The mean age at puberty for 1982-83 was 693.6 days (23.1 months) for Corriedale and 483.3 days (16.1 months) for Criollo. The mean liveweight at puberty was 27.2 kg for Corriedale, and 25.3 kg for Criollo. Corriedale ewe lambs weighed more than Criollo, attained puberty seven months later than Criollo. At comparable age (15-17 months) at the Southern Peruvian Highlands 100 % of the Criollo reached puberty, compared to 58% of the Corriedale. Body weight, incidence of estrus and ovulation were affected (P<.01) by breed, age, year, month, and their interactions. Physical maturity was attained at 39 and 36 months of age for Corriedale, and Criollo, respectively. Weight changes during the year were associated with feed availability. The mean overall incidence of estrus was 45.4 % for Corriedale (43.6 in physically immature, and 47.2 % in mature ewes), and 67.1 % for Criollo ewes (66.3, in physically immature, and 68.7 % in mature ewes). The mean overall incidence of ovulation was 39.6 % for Corriedale (39.7, in physically immature, and 39.5 % in mature ewes), and 58.5 % for Criollo ewes (59.4, in physically immature and 56.7 % in mature ewes). Both breeds demonstrated seasonality of estrus and ovulation with the Corriedale being shorter than the Criollo. The incidence of ovulation in both breeds was less than that of estrus. The ovulation rate was 1.00 for Corriedale, and 1.03 for Criollo (P>.05). Even though Criollo ewes weighed less than Corriedale, they attained puberty earlier, and showed less seasonality in estrus and ovulated …