Physical Sciences and Mathematics Commons^™

Determining The Effects Of The Think Risk Initiative As Implemented By The Southern Nevada Health District, Karalin Nichole Cronkhite

UNLV Theses, Dissertations, Professional Papers, and Capstones

In the United States, someone becomes infected with a foodborne illness every 2 seconds, is hospitalized by a foodborne illness every 4 minutes and dies due to a foodborne illness every 3 hours. Foodborne illness is preventable, yet each year, 1 in 6 Americans is affected by it from contaminated foods or beverages. There are over 250 different foodborne diseases, and in 2015, there were 73 confirmed cases of Salmonella infection in Southern Nevada alone. Since the emergence of public health, food establishment inspections have been an important part of the regulation of food safety. Risk-based inspections were developed by …

Biogeochemistry Of A Saline, Alkaline, Terminal Lake Ecosystem In Transition; Walker Lake, Nevada, Katherine Lynn Willever

UNLV Theses, Dissertations, Professional Papers, and Capstones

Walker Lake is a saline, alkaline, terminal lake ecosystem located in west-central Nevada. For over one hundred years, anthropogenic streamflow diversions within the Walker River Basin have ultimately led to little or no water reaching Walker Lake, the basin’s terminus for water flow. These diversions have resulted in a >46 meter decrease in the lake surface altitude and increases in salinity and dissolved salt constituents that have caused the elimination of native fish species. This study examines how the lack of freshwater inflow has altered the physical, chemical, and microbiological structure of Walker Lake during the lake’s ongoing desiccation.

Between …

The San1 Ubiquitin Ligase Functions Preferentially With Ubiquitin-Conjugating Enzyme Ubc1 During Protein Quality Control, Rebeca Lea Ibarra

UNLV Theses, Dissertations, Professional Papers, and Capstones

Protein quality control (PQC) is a critical process wherein misfolded or damaged proteins are cleared from the cell to maintain protein homeostasis. In eukaryotic cells, the removal of misfolded proteins is primarily accomplished by the ubiquitin-proteasome system (UPS). In the UPS, ubiquitin-conjugating enzymes and ubiquitin ligases append poly-ubiquitin chains onto misfolded protein substrates signaling for their degradation. The kinetics of protein ubiquitylation are paramount since a balance must be achieved between the rapid removal of misfolded proteins versus providing sufficient time for protein chaperones to attempt refolding. To uncover the molecular basis for how PQC substrate ubiquitylation rates are controlled, …

Incomplete Denitrification In Thermus Species, Chrisabelle Mefferd

UNLV Theses, Dissertations, Professional Papers, and Capstones

Members the bacterial genus Thermus have been shown to be incomplete denitrifiers, terminating with nitrite or nitrous oxide (N2O). However, the ability to carry out denitrification and the evolution of nitrogen oxide reductase genes in Thermus remains poorly understood. This study tests the hypothesis that incomplete denitrification is common in Thermus and seeks to uncover patterns in the evolution of denitrification pathways in Thermus. Denitrification capacity was determined in a collection of 25 strains representing ten species of Thermus and phylogenetic analysis was performed to determine whether denitrification genes evolved horizontally in Thermus. No strains in this study reduced nitrate …

Water Source Partitioning For Shrubland Transpiration In A Mixed Phreatophytic Plant Community, Amanda Jean Wagner

UNLV Theses, Dissertations, Professional Papers, and Capstones

Groundwater in the basins of east central Nevada (Great Basin Desert, NV) has been permitted for export to southern Nevada. These basins are also vulnerable to changes in climate that could lead to declining recharge. Any decline in groundwater levels no matter the driving force could significantly impact phreatophytes (deep rooted shrubs), which utilize water from both the vadose zone and the capillary fringe to meet plant water needs, to support growth, and for overall health. A reduction in groundwater due to these forces could have a significant impact on the decoupling of phreatophytes from what is normally a reliable …

Impacts To Phytoplankton After The Establishment Of Quagga Mussels In Lake Mead, Nevada, Warren Bruce Turkett

UNLV Theses, Dissertations, Professional Papers, and Capstones

Quagga mussels (Dreissena rostriformis bugensis) are an invasive species that were discovered in Lake Mead in January of 2007, and rapidly spread throughout the lake. Quagga mussels are about the size of a fingernail, but are known to clog pipes, damage infrastructure and alter ecosystems. In large numbers, mussels can have a dramatic impact on an ecosystem by reducing the phytoplankton and potentially increasing toxin producing cyanobacteria. This research analyzed data collected from three separate basins in Lake Mead to determine if water quality characteristics that are commonly impacted by invasive mussels have changed. Transparency, chlorophyll-a, phytoplankton and zooplankton samples …