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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.
71

Evaluation of Stream Bottom Fauna Sampling Techniques as used in the Logan River

Hales, Donald C. 01 May 1955 (has links)
The square-foot bottom sampler has been the principle instrument used for quantitative studies of the bottom fauna in riffle areas of streams. However little has been written concerning the actual number of square-foot samples necessary to describe stream bottom fauna in terms of the number or volume of organisms. The object of this study is to determine the minimum number of bottom samples that adequately describe the bottom at any time or location. The study areas are located in Logan River, Utah, and two of its tributaries: Temple Fork and Beaver Creek.
72

Comparing Different Methods for Determining Moisture in Wheat Using NESR Infrared Reflectance Spectroscopy

Chang, Weider 01 May 1987 (has links)
One hundred wheat samples, with moisture ranging from 14.42 %to 7.66 %, were used to test the moisture loss from grinding, the accuracy of moisture content from two different electric moisture meters, and the accuracy and precision of Near Infrared Reflectance Spectroscopy whole wheat moisture determination. Fifty samples were ground through three grinders, Wiley, Cemotec , and UDY Cyclone grinder. Moisture content was determined from these ground samples, and compared with whole wheat moisture. The Cemotec grinder caused the least amount of moisture loss, followed by Wiley and then UDY Cyclone. Fifty whole wheat samples were used to calibrate the Tecator GP6010 moisture meter. Another 50 whole wheat samples with known moisture values, were used to test the accuracy of the Tecator GP6010 moisture meter. Moisture and compared to moisture readings from a Motomco meter. Tecator moisture value had a better correlation coefficient to whole wheat moisture than Motomco moisture values (0.935 and 0.917, respectively). Three sample sets from different grinding preparation methods were scanned by NIRS . Eight moisture values were entered into the computer, and separate multiple regression equations developed. Sixteen wheat samples with known moisture content were used to test the equations. For .whole wheat moisture equation, SEA and r 2 were 0.159 and 0.991, 0.223 and 0.972, 0 .223 and 0 .973, 0.322 and 0.888, 0.218 and 0.968, 0.248 and 0.969 , 0.208 and 0.978 , 0.249 and 0.970 for whole wheat, Cemotec, Wiley, UDY, C3 , C5, C6, and Motomco moisture, respectively. For Cemotec moisture equation, SEA and r2 were 0.226 and 0.944, 0.208 and 0.927, 2.267 and 0.071, 0.208 and 0.853, 0.272 and 0.876, 2.296 and 0.088, 0.291 and 0.896, 0.248 and 0.927, for whole wheat, Cemotec, Wiley, Udy, C3, CS , C6, and Motomco moisture, respectively. For UDY moisture equation, SEA and r2 were 0 .402 and 0.909, 0.364 and 0.900, 0.353 and 0.907, 0.119 and 0 .973, 0.407 and 0.858, 0.484 and 0.856, 0.514 and 0.835, 0.403 and 0.897, for whole wheat, Cemotec, Wiley, UDY, Tecator C3, CS, C6, and Motomco moisture, respectively. Many desirable features make the whole wheat method a good direction for Near Infrared Reflectance Spectroscopy.
73

Compounds in Bovine Urine Which Change in Concentration During the Estrous Cycle: Possible Pheromones

Johnson, Scott Kay 01 May 1987 (has links)
During the last thirty years it has become increasingly apparent that pheromones play a major role in animal communication. Of economic interest to agriculturalists is the role pheromones play in signaling the state of estrus. The ability to efficiently detect estrus is becoming increasingly important, especially in the management of dairy and beef herds, where artificial insemination is used extensively. The understanding of pheromones may eventually provide a solution to this problem. The purpose of this study was to identify one or more compounds in the urine of cattle which undergo a change in concentration during the estrous cycle. In order to accomplish the objectives of this study, urine was obtained from cows exhibiting estrus and again 7 days post estrus. The urine was extracted with ether and the extract analyzed by gas chromatography. The area under each chromatographic peak was determined by integration. Areas were analyzed for variance between estrus and di-estrus. An attempt was made to identify each of the compounds represented by those peaks which proved to have statistically different concentrations . Two significant peaks were identified by coinjection with standards and found to represent propionic acid and iso-caproic acid. Three other statistically significant peaks were analyzed by mass spectrometry but concentrations were too low to determine the identities. Results indicate that propionic acid, iso-caproic acid and two of the unidentified compounds decrease in concentration during estrus. The third unidentified compound was found to increase during estrus. studies have not yet been done to show pheromonal properties, however, the first step to allow such studies has now been accomplished. Five compounds have been found which change in concentration during estrus. Because the changes reflect similar concentration changes in pheromones, it is believed that they may eventually prove to be pheromonal.
74

Vulnerability of Cougars to Hunting

Barnhurst, Dan 01 May 1986 (has links)
Forty radio-collared cougars (Felis concolor) were monitored for 630 cougar months. Track searches were conducted and tracking information was gathered over a 20-month period. Vulnerability was estimated to be greatest for 0 to 6-month-old kittens. This age class is the most susceptible to starvation after being orphaned, or being killed by hounds when the hunter is unaware of their presence, since their tracks were found with their mother's tracks only 19 percent of the time. Tracks of 7 to 12-month old kittens were found with their mother's tracks 43 percent of the time. Relative road-crossing frequencies of seven classes of transients and resident adults were derived from sequential, aerial telemetry locations. Significant differences (P < 0.043) in crossing frequencies were found among these classes. A relative vulnerability index, based on road-crossing frequencies, was calculated for each class. Compared to an average vulnerability index of one for all classes, resident females without kittens, and those with 0 to 6-month, 7 to 12-month, and 13 to 18-month-old kittens, had relative vulnerability indices of 0 . 6, 0.5, 0.83, and 0.78, respectively. Transient females, resident males and transient males had indices of 0.93, 0.95, and 1.35, respectively. After two years of experimental hunts, where the average density of harvestable cougars (kittens and females accompanied by kittens excluded) 2 was 0.71/100 km, hunters found an average of 1.3 tracks per day and started their hounds on 1 in 3.8 of these tracks. Treeing a cougar required an average of 8.7 hunting days and covering 559 km of road during track searches. The level of experience of the hunter and his hounds appeared to be very important in determining hunting success. How the differential vulnerability between cougar classes may affect the composition of the hunter harvest was also discussed.
75

The Diet and Daily Forage Consumption of an Experimental Herd of Sheep on Utah's Winter Range

Sharp, Lee A. 01 May 1949 (has links)
The forage. produced on Utah’s winter range is generally deficient in some nutrients that are required for the phase of sheep production that takes place on these ranges. This forage need only supply little more than maintenance ration, but because of low forage production on these areas and generally low quality forage, these requirements often are not met.
76

Effect of Overall Indispensible Amino Acid Levels on Performance of Broiler Chicks

Kelly, Jack D. 01 May 1985 (has links)
An attempt was made to determine the effect of overall indispensible amino acids (IAAs} level on growth rate and efficiency of broiler chicks. There were two overall levels: the low (8.33% IAA, 17.6% CP containing all IAAs at the minimum requirement found in preliminary studies), and the high (10.77% IAA, 21.5% CP with IAAs increased by 28%). Both diets contained 13.7 Mega joules ME (3277 Kcal) per kilogram. These two diets along with other variations of the two diets were fed to Hubbard chicks. Growth rate , with the low IAA diet was as good as with the high, but feed efficiency was significantly better for the high. When one of the IAAs was reduced from the higher to the minimum estimate, feed efficiency was better than the low overall diet. Two additional diets with the low levels of IAAs and dispensible amino acids increased were fed to male Hubbards. Protein level was increased by the addition of DAAs but did not improve either growth rate or feed efficiency. Therefore, it was concluded that feed efficiency was not improved by increasing DAAs alone.
77

Nutrition and Feeding Behavior of Goats and Sheep Grazing Deciduous Shrub-Woodland in Northeastern Brazil

Pfister, James Alan 01 May 1983 (has links)
Production of sheep and goats in the Brazilian Northeast is important for the livelihood of both subsistence and market-oriented producers. Seasonal nutritional stress oh animals in the caatinga vegetational zone of this region causes periodic high mortality and chronically low productivity. Under such conditions, the survivability of goats has been higher than for other domestic livestock. Possible reasons for this include unique aspects of dietary selection and goat feeding behavior. The objectives of this research were to seasonally determine the botanical and nutritive content of goat and sheep diets, to determine forage intake by grazing goats and sheep, and to compare their feeding behavior. Dietary selections by sheep and goats were similar during the dry season, but diverged markedly during the wet season. Leaf litter from the deciduous trees was the major dietary component for both species during the dry season, and provided the bulk of dry season forage. Current hypotheses predict that goats select diets of higher nutritional quality and have a greater forage intake than do sheep. Goats selected diets significantly (P.05) in cell wall content, and lower (P This study confirmed the vertical stratification of foraging by goats and sheep. Sheep foraged more in lower vertical strata than did goats. Goats spent about 4% of their grazing time in a bipedal stance, while sheep virtually never used a bipedal stance to feed. In addition, no nutritional advantage was found for goats over sheep through use of a bipedal stance. This latter finding is constrained by the deciduous nature of the caatinga woodland during the dry season.
78

Color Vision in the Bovine

Gilbert, B. John 01 May 1985 (has links)
Eight heifers were trained using operant conditioning to press a plate to receive a feed reward. Different wavelengths of light were presented as correct and incorrect stimuli. Positive and negative responses to the stimuli were registered electronically. Daily sessions of 17 minutes were conducted in a chamber with external light being excluded. The duration of the stimulus was fixed at 17 seconds after which stimuli were randomly presented. Only presses on the plate when the correct stimulus was presented were reinforced with feed. A 75% correct choice was the criterion used as acceptable discrimination. Ratios of correct to incorrect responses were computed. A stability of response was judged to occur when the median of these ratios over 5 days did not differ by more than .05 from the median of the ratios from the previous 5 sessions. Three colors i.e. green {535nm), red {610nm), and blue {450nm) were compared pairwise during 8 trials. Trial 7 was a repeat trial of green vs red and trial 8 was a comparison of green vs green. Heifers gave random response to green vs green. Red was distinguished from blue by five of the heifers: 1, 2, 3, 4, and 5 at 76%, 91%, 78%, 88%, and 81% correct choice respectively. Blue was distinguished from green by three of the heifers: 1, 2, and 5 at 89%, 88%, and 85% correct choice respectively. Green was distinguished from red by three of the heifers: 1, 5, and 7 at 90%, 84%, and 85% correct choice respectively. These last discriminations we r e made in the repeat trial of green vs red after heifers failed to do so in the first trial of green vs red. Color discrimination and discrimination learning have been demonstrated by these results.
79

An Ecological Study of the Utah Sculpin Cottus Bairdi Semiscaber in Logan River, Utah

Zarbock, William Merle 01 May 1951 (has links)
The study of the Utah sculpin (Cottus bairdi semiscaber), or Rocky Mountain bullhead as it is known locally on Logan River, Utah, is primarily one of determining its relation to game fish. Field work for this study began in 1949 and continued to March of 1951. Numbers of the Utah sculpin on Logan River have been estimated to be as high as 150 per tenth mile of stream. The larger populations are in the area of the third impoundment on Logan River and downstream.
80

Rangeland Resources Monitoring: Concepts and Practical Applications

Bobwski, Benny R. 01 May 2001 (has links)
How does one person manage and monitor a half million acres of rangelands towards a sustainable future? Through a journey that begins with the understanding of sustainability, I explore the monitoring concept, two -of its applications, and summarize with an emphasis on the art and science of management. Sustainability is a concept that confuses many managers because it is so complex. However, if one considers adaptability as the complement to sustainability, and realizes that an adaptable organism is a sustainable organism, then a manager can relate because the emphasis shifts from that of stability for the future to that of uncertainty for today. The need for monitoring becomes self-evident as it is used to observe the environment and warn people against the presence of variables thought to be harmful. Interestingly, professionals who monitor rangelands have not adopted statistical power analysis to aid in change detection. Moreover, range professionals do not have many tools to monitor a half million acres in a statistically and biologically meaningful way. I explored the role of power analysis in evaluating range trend data. In addition, I tested a low aerial photography method for monitoring vegetation cover across rangeland landscapes. The investigations revealed that when monitoring is used as a feedback loop, the information acquired would likely facilitate adaptability and therefore sustainability of resources and people. However, most monitoring programs offer limited information of low statistical power at an inappropriate scale. Therefore, monitoring information should be used with ancillary scientific information to direct decisions, not drive them. We will continue to rely upon both the art and science of management to keep us following a path towards sustainability.

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