Thesis (M.S.)--Oregon State University, 1977. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 1977. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.

Thesis--University of Florida. / Manuscript copy. Vita. Description based on print version record. Bibliography: leaves 61-63.

Graduation date: 1955

In the upper Sonoran and transition zone areas of southern British Columbia populations of Perognathus parvus living in different habitats exist within a few miles of each other. The area was deglaciated about 10,000 years ago setting a maximum time for occupancy by small mammals. This study was initiated to compare the adaptations of individuals of these populations to the different habitats and, if possible, comment on their evolution and distribution. Animals from an environmental gradient were examined in the field and laboratory. One end of the environmental continum (low area) was characterized by low rainfall, high temperatures and a long summer, the other (high area) by high rainfall, low temperatures and a long winter. Specimens from kill trapping indicated that the subspecies under consideration was morphologically variable with characteristics distributed in a checkerboard pattern. Analysis of stomach contents indicated that food during the summer was about equally divided between seeds, green vegetation and animal material. Seeds were the major item stored for winter food. Low area animals ate comparatively more green vegetation, possibly in response to greater water loss. Intensive live trapping and dissection of specimens indicated that high area females came into reproductive condition earlier in the spring and ceased reproducing earlier in the summer, producing fewer litters than the low area females. Young-of-year females in the low area reproduced while those in the high area did not. Average litter sizes (4.85) were the same. There was no postpartum estrus. Home ranges sizes of males (895 m²) in the high and low areas were the same. The ranges of the females (656 m²) were smaller. Burrows and home range centers were apparently randomly distributed and ranges of both sexes overlapped. Density was highest in the low area and decreased with altitude. Long term survival rates were high in all groups except low area young animals. Short term survival rates were highest in the winter, lowest in the spring and intermediate in the summer and fall. High area animals entered torpor earlier in the fall than did low area animals. Adults apparently entered torpor before young animals. In the laboratory animals tended to enter torpor during the dark period and leave torpor during the light period after 3-168 ([formula omitted] = 46) hours in torpor. Percent of time spent in torpor increased with time at 5 C and levelled off at about 60%. When maintained at low temperatures high area animals had significantly longer torpor periods and spent a greater proportion of time in torpor than did low area animals. Subjection to water stress indicated that the low area animals were better able to conserve water by reacting more quickly to dehydration. When dehydrated low area animals were able to maintain allow plasma osmotic concentration while high area animals were not. The production of highly concentrated urine appeared to be the main reaction to dehydration. Fecal and evaporative rates of water loss were similar to those found in other small desert rodents and did not consistently decrease with dehydration. Both high and low area animals maintained their weight on a dry diet at 76% humidity at 20 C but lost weight at 42% humidity. It is suggested that the northern distribution of P. parvus is limited by the short summer season available for birth and establishment of the young. Analysis of morphological characters shows that genetic differences exist between individuals of the two populations. Concrete evidence of genetic differences in physiological characteristics is lacking but a strong circumstantial case for the existence of such differences can be built. It is suggested that high selection pressures have been more responsible for the differentiation of the populations than has restricted gene flow. / Science, Faculty of / Zoology, Department of / Graduate

Thesis (Ph. D.)--University of Florida, 1982. / Description based on print version record. Typescript. Vita. Includes bibliographical references (leaves 199-207).

Call number: LD2668 .T4 1933 C32

Thesis (M.S.)--Georgia State University, 2004. / Title from title screen. Sushil K. Prasad, committee chair; Anu Bourgeois, Alex Zelikovsky, committee members. Description based on contents viewed Feb. 26, 2007. Includes bibliographical references (p. 55-59). Source code: p. 75-123.

I used field experiments to study how plants in two grassland communities colonized soil mounds made by the Camas pocket gopher, Thomomys bulbivorus (Richardson). I identified potential mound colonizers in each source of colonization (buried propagule bank, seed rain, and established vegetation) and then measured species specific rates of colonization on mounds built by T. bulbivorus. By selectively eliminating different avenues of colonization on artificial mounds, I estimated the relative and combined effects of colonization from (1) germination and growth of buried viable seeds and growth of root fragments in the soil; (2) germination of seeds raining onto the mounds; (3) emergence of buried vegetation and, (4) encroachment and establishment of adjacent vegetation. Artificial mounds were good mimics of mounds built by T. bulbivorus judged by their similarity in colonization rates and composition of colonizing species. I repeated the investigation in adjacent pasture and prairie communities differing in species composition and abundances to compare the effects of these differences on the colonization process. Composition and abundance of species in the expressed and potential vegetation varied considerably between pasture and prairie as did the two communities' response to identical gopher disturbances. Percent cover of vegetation on mounds increased 3 times faster in the Composition and abundance of species in the expressed and potential vegetation varied considerably between pasture and prairie as did the two communities' response to identical gopher disturbances. Percent cover of vegetation on mounds increased 3 times faster in the pasture than the prairie; and vegetation on and off mounds in the pasture was more alike (71% Similarity) than vegetation on and off mounds in the prairie (50% Similarity). Despite these differences, the relative contribution of each source of colonization was strikingly similar in the two communities. Vegetative encroachment and emergence contributed more to overall colonization rates (76% in the pasture; 75% in the prairie) than did establishment from seeds or buried root fragments. Emergence from underneath the mounds was favored by the shallow depth of mounds, minimal alteration of the substrate associated with mound building, and dominance of perennial species with erect growth forms. The small area and high perimeter to surface area ratio resulted in a high percent colonization from encroachment of surrounding vegetation. Colonization from the rain and bank contributed less to mound closure and may have been limited by a low abundance of propagules in those two sources. Successful colonists differed in their patterns of colonization. Festuca rubra, Agoseris heterophylla, Plantago lanceolata and Prune lla vulgaris colonized almost exclusively via emergence. Fragaria virginiana colonized by the extension of stolons both onto (encroachment) and up through mounds (emergence). Colonization from the seed rain was important in many annual species, such as Ranunculus occidentalis, Clarkia quadrivulnera, and Sherardia arvensis and the biennial species, Hypericum perforatum. One annual species, Cynosurus echinatus colonized to some degree from several modes of colonization. Mound disturbances had greater forb and annual species cover in both communities than was represented in the background vegetation, although the difference was much greater in the prairie. Results of this and other studies of gopher disturbance suggest that the relative abundance of perennials and annuals, evenness of species abundance and competitive relationships can help to predict patterns of colonization and effects of gopher mounds on community diversity. / Graduation date: 1991

In this thesis, we develops a Pocket PC-based 3D object design system using implicit functions, which allows users to design and view 3D objects easily at anytime and anywhere. With the growing wireless techniques, Pocket PC can easily connect to the Internet via WLAN, GPRS, WCDMA, etc. The problems of insufficient computing power caused by the limited hardware on Pocket PCs can be solved by the client-server model, which performs complex computation on the workstation, and transmit polygon mesh data to the Pocket PC. Via the proposed system, one can design and visualize his any innovative ideas instantly wherever he is.