Habitat Fragmentation by Land-Use Change: One-Horned Rhinoceros in Nepal and Red-Cockaded Woodpecker in Texas (open access)

Habitat Fragmentation by Land-Use Change: One-Horned Rhinoceros in Nepal and Red-Cockaded Woodpecker in Texas

This research focuses on the spatial analysis of the habitat of two vulnerable species, the one-horn rhinoceros in the grasslands of southern Nepal, and the red-cockaded woodpecker in the Piney woods of southeast Texas, in the USA. A study sites relevant for biodiversity conservation was selected in each country: Chitwan National Park in Nepal, and areas near the Big Thicket National Preserve in Texas. Land-use differs in the two study areas: the first is still undergoing agrarian development while the second is in a technological phase and undergoing urbanization processes. Satellite remote sensing images were used to derive land-cover maps by supervised classification. These maps were then processed by Geographic Information Systems methods to apply habitat models based on basic resources (food and cover) and obtain habitat suitability maps. Several landscape metrics were computed to quantify the habitat characteristics especially the composition and configuration of suitable habitat patches. Sensitivity analyses were performed as the nominal values of some of the model parameters were arbitrary. Development potential probability models were used to hypothesize changes in land-use of the second study site. Various scenarios were employed to examine the impact of development on the habitat of red-cockaded woodpecker. The method derived in …
Date: December 2010
Creator: Thapa, Vivek
System: The UNT Digital Library
Photoactivatable Quantum Dots in Super-Resolution Microscopy of Muscle (open access)

Photoactivatable Quantum Dots in Super-Resolution Microscopy of Muscle

Super-resolution 3D imaging was achieved using newly synthesized photoactivatable quantum dot (PAQ dot) probes. Quantum dots were modified with a novel quencher system to make them photoactivatable. The unique properties of these PAQ dots enable single-fluorophore localization in three dimensions using a confocal microscopy optical sectioning method. Myosin and tropomyosin of rabbit myofibrilar bundles were specifically labeled with the newly synthesized PAQ dot. A sufficient number of single quantum dots were photoactivated, localized and reduced to their centroid and then reconstructed to a super-resolution image. The acquired super-resolution image shows a lateral and an axial sub-diffraction resolution and demonstrates ultrafine striations with widths less than 70 nm that are not evident by conventional confocal microscopy. The striations appear to be related to nebulin thin filament binding protein. This newly developed imaging system is cutting edge for its high resolution and localization as well its simplicity and convenience.
Date: December 2010
Creator: Akel, Amal
System: The UNT Digital Library
Museum education: Creation, implementation, and evaluation of a web-based Elm Fork Natural Heritage Museum (open access)

Museum education: Creation, implementation, and evaluation of a web-based Elm Fork Natural Heritage Museum

Evaluation of museum audiences both in their physical and web-based spaces is a necessary component of museum education. For smaller museums without the personnel or knowledge to create a website and evaluate the on-line audience, using a web-based learning tool may be able to help these museums properly maintain an online site. A web-based Elm Fork Natural Heritage Museum (WBEFNHM) was created during the 2008 fall semester at the University of North Texas. The site included photographs and information from specimens housed within the physical Elm Fork Natural Heritage Museum. The site was available to three non-science majors' biology laboratory courses, and three science majors' biology laboratory courses during the 2009 spring and fall semesters. Student use of the WBEFNHM was tracked and found no significant difference between the amount of time science majors and non-majors spent on the site. This evaluation helps in understanding future use of an online EFNHM.
Date: December 2010
Creator: Lundeen, Melissa
System: The UNT Digital Library
Genetic and Environmental Factors that Mediate Survival of Prolonged Oxygen Deprivation in the Nematode Caenorhabditis Elegans (open access)

Genetic and Environmental Factors that Mediate Survival of Prolonged Oxygen Deprivation in the Nematode Caenorhabditis Elegans

Ischemic events of even a very short duration are not tolerated Ill in humans. The human cost of ischemia, when looked at as combined cardiovascular disease, dwarfs all other causes of death in the United States. Annually, CVD kills as many people in the US as does cancer, chronic lower respiratory disease, accidents, and diabetes mellitus combined. In 2005 (the latest year for which final statistics are available), CVD was responsible for 864,480 deaths or 35.3 percent of total deaths for the year. In my study, I have used the nematode Caenorhabditis elegans to determine genetic and environmental modulators of oxygen deprivation a key component of ischemia. I have found that animals with mutations in insulin like signaling pathways, neuronal function, electron transport chain components, germline function, and animals that are preconditioned by being raised on a diet of E. coli HT115 bacteria at 25°C have an enhanced ability to survive long-term (>72 hours) anoxia (<.005 kPa O2) at 20°C. The enhanced anoxia survival phenotype partially correlates with increased levels of carbohydrate stores in the nematodes. Suppression of this enhanced anoxia survival phenotype is possible by altering expression of the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase, the FOXO transcription factor DAF-16, and …
Date: August 2010
Creator: LaRue, Bobby Lee, Jr.
System: The UNT Digital Library