Understanding thickness variation and facies transitions in the mudstone-rich part of the Upper Middle Jurassic (Callovian) Entrada Sandstone depositional system is critical for constraining the paleogeography and evaluating the economic potential of Utah's Entrada Sandstone. Facies of the Entrada Sandstone in south-central Utah are dominated by mudstone-rich intertidal facies that were widespread within the Jurassic seaway. Intertidal deposits interfinger basinward with subtidal ooid-bearing shoals and bars, and landward supratidal sabkha, and erg-margin eolian deposits. Three sections were measured to improve understanding of the lateral and vertical facies transitions. Variations in thickness indicate the rate of developing accommodation space was high along the southwestern shoreline and relatively low along the northeastern shoreline during Callovian time. Although accommodation space was highest in the west, sediment supply from the west kept pace with, and eventually outpaced subsidence. In the east, sediment supply was significant but at one time was outpaced by subsidence, creating a complete range of facies, from subtidal to supratidal deposits. Along this eastern shoreline, erg-margin coastal dunes associated with the larger erg to the east eventually prograded westward. The variation in subsidence, sediment supply, and sediment source makes sequence stratigraphic correlation difficult. Reservoir-quality sandstones are associated with muddy sections of the Entrada Sandstone within the San Rafael Swell. Porosity and permeability of the facies in this area indicate excellent reservoir potential in three of eight facies that were studied. Porosities of these potential reservoirs ranged from 11-22%, with permeabilities ranging from 44-430md. These high quality reservoir facies are surrounded by muddy, low reservoir-quality rocks, creating conditions amenable to the development of stratigraphic hydrocarbon traps. Based on further study and a modern analog at the north of the Gulf of California, Hicks and others' (2010) depositional model for the Entrada Sandstone of south-central Utah has been modified to include newly interpreted facies. This improved depositional model may have predictive power in exploring for stratigraphic and combination traps within the Entrada system of Utah and analogous depositional systems throughout the world.

Minority carrier transport properties and the effects of electron irradiation/injection were studied in GaN and ZnO containing dopants known to form acceptor states deep within the materials' bandgap. Minority carrier diffusion length and lifetime changes were investigated using Electron Beam Induced Current (EBIC) method, cathodoluminescence spectroscopy, spectral photoresponse and persistent photoconductivity measurements. It is shown that electron irradiation by the beam of a scanning electron microscope results in a significant increase of minority carrier diffusion length. These findings are supported by the cathodoluminescence measurements that demonstrate the decay of near-band-edge intensity as a consequence of increasing carrier lifetime under continuous irradiation by the electron beam. Temperature-dependent measurements were used to determine the activation energies for the electron irradiation-induced effects. The latter energies were found to be consistent with the involvement of deep acceptor states. Based on these findings, the effects of electron irradiation are explained via the mechanism involving carrier trapping on these levels. Solid-state electron injection was also shown to result in a similar increase of minority carrier lifetime and diffusion length. Solid-state injection was carried out by applying the forward bias to a ZnO homojunction and resulted in a significant improvement of the peak photoresponse of the junction. This improvement was unambiguously correlated with the increase of the minority carrier diffusion length due to electron injection.

Energy is an essential resource for supporting everyday life and economic development. Among numerous approaches which people use to collect energy, photovoltaics stands out for two factors: it allows to obtain electricity by exploiting an abundant source of solar energy and it does it in an environmentally friendly way. In recent years, the development of organic solar cells gained a large interest as this technology offers low-cost, light-weight and flexible devices. Moreover, in contrast to inorganic semiconductors, organics offers a variety of materials with optoelectronic properties tailored in a wide range. To further increase the solar cell efficiency, it is important to study charge-carrier transport, that is strongly influenced by the presence of trap states. Organic semiconductors are particularly prone to the formation of such states due to the weak attraction between molecules. No investigation of trap states has been done for oligothiophenes so far in spite of their excellent performance in organic solar cells. In this work, the blend of the dicyanovinyl end-capped oligothiophene DCV5T-Me and C60 is studied on the presence of trap states. This material showed high efficiencies in vacuum-processed small-molecule organic solar cells with a PCE of the best single-junction cell of 8.3% and a fill factor (FF) of 65.8%. The traps are investigated by using impedance spectroscopy (IS) and thermally stimulated currents (TSC) measurements. The blend DCV5T-Me:C60 (2:1, 80°C) contains two types of electron and a set of hole trap states. A deep Gaussian distributed electron trap at 470 meV (with respect to the transport level) is observed in the blend by IS measurements. Its origin is attributed to the distortion of the natural morphology in the C60 phase due to the intermixing of donor and acceptor molecules. Moreover, a shallow Gaussian distributed electron trap at 100 meV (with respect to the transport level) is observed in neat C60 by IS measurements. Finally, a distribution of shallow trap states with depth below 200 meV (with respect to the transport level) and overall trap density of Nt > 8.7E+16 cm^−3 is indicated in the blend by TSC measurements. The majority of these defects is attributed to hole trap states in the DCV5T-Me phase. The deep electron traps at 470 meV reduce the free charge carrier density and act as recombination centers, leading to trap-assisted recombination. According to drift-diffusion simulations, these deep traps lead to the relative reduction of FF of about 10%. The hole trap states in DCV5T-Me can explain a reduced hole mobility of μh=7E−5 cm^2/(Vs), which is limiting for the solar cell performance as it is two orders of magnitude lower than the electron mobility.

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Neutrophil extracellular traps (NETs) are a link between infection and coagulation in sepsis. The major structural component of NETs is nucleosomes, consisting of DNA and histones. NETs not only act as a scaffold to trap platelets, but NET components also promote coagulation and impair fibrinolysis. Thus, removal of extracellular DNA by DNases may be a potential therapeutic strategy for sepsis. Since heparin is used for thromboprophylaxis in sepsis and may also be a potential anti-sepsis therapy, we investigated the mechanisms by which various forms of heparins modulate DNase function. There are two types of DNases in vivo: DNase I (produced by exocrine and endocrine glands) and DNase1L3 (secreted by immune cells). DNase I cleaves free DNA, whereas DNase1L3 preferentially cleaves DNA in complex with proteins such as histones. In this study, we investigated how DNase I and DNase1L3 activities are modulated by the following heparins: unfractionated heparin (UFH), enoxaparin (a low-molecular-weight heparin), Vasoflux (a low-molecular-weight, non-anticoagulant heparin), and fondaparinux (the pentasaccharide unit). Using agarose gel experiments, we showed that UFH, enoxaparin, and Vasoflux enhance the ability of DNase I to digest DNA-histone complexes (presumably by displacing DNA from histones), whereas fondaparinux does not. These findings are consistent with the KD values of the binding of heparin variants to histones, with fondaparinux having >1000-fold lower affinity for histones compared to the other heparins. Taken together, our data suggests that the ability of heparin to enhance DNase I-mediated digestion of DNA-histone complexes is size-dependent and independent of the pentasaccharide region of heparin. With respect to DNase1L3, we observed that it is able to digest histone-bound DNA, and that all heparins, except fondaparinux, inhibited DNase1L3-mediated digestion of histone-bound DNA. Next, we visualized the degradation of NETs by fluorescence microscopy. DNase I (± heparin variants) completely degraded NETs, presumably by digesting extracellular chromatin at histone-free linker regions, thereby releasing nucleosome units. DNase1L3 also degraded NETs, but not as effectively as DNase I, and was inhibited by all heparins except fondaparinux. Finally, we showed that DNase I levels are decreased and DNase1L3 levels are elevated in septic patients. Taken together, our findings demonstrate that heparin modulates the function of DNases, and that endogenous DNase levels are altered in sepsis pathophysiology. / Thesis / Master of Science (MSc) / Sepsis, a life-threatening condition due to hyperactivation of the immune system in response to infection, results in widespread inflammation and blood clotting. During sepsis, immune cells release sticky strands of DNA that block blood vessels and damage organs. Two different enzymes in the blood (DNase I and DNase1L3) can digest these DNA strands, and may represent a new class of anti-sepsis drugs. Our goal was to determine how heparins, commonly used blood thinners, alter the function of these enzymes. We found that (a) larger-sized heparins improved the activity of DNase I towards DNA-histone complexes and do not require any specific portion of heparin, (b) DNase I is more efficient than DNase1L3 in digesting DNA strands released from immune cells, and (c) levels of DNase I and DNase1L3 are altered in septic patients. Taken together, our studies provide new insights into how these enzymes function.

There has been little research comprehensively documenting wildlife species in Harenna Forest within the Bale Mountains National Park of Ethiopia. This area is one of the few remaining afro-alpine biodiversity hotspots and is home to numerous endemic plants and animals and offers socio-economic benefits to the neighboring communities. Human population pressure, weak land protection policies, and uncertain land tenure rights have led to increases in farmland for subsistence and coffee farming, livestock grazing, and reduction of afro-alpine, shrubland and grassland habitats. Given these challenges, I used 48 camera trap stations to produce an inventory of wildlife species and to determine factors influencing occupancy (i.e., habitat use), detection, and temporal activity and overlap. I recorded 26 terrestrial and arboreal mammalian species and I had sufficient data to model occupancy for 13 species and temporal activity for 14 species. Occupancy and detection were generally higher for herbivores and omnivores (occupancy: 0.28-0.97; detection: 0.1-0.54) than carnivores (occupancy: 0.31-0.80; detection: 0.04-0.18). I found more evidence of positive anthropogenic impacts on herbivore and omnivore occupancy than negative, while detection was influenced by habitat or landscape features, rather than by humans. Carnivore occupancy was largely unaffected by anthropogenic or habitat variables, but detection was strongly, and mostly positively, influenced by anthropogenic impacts. Temporal activity analyses revealed that, for herbivores and omnivores, only tree hyraxes (Dendrohyrax arboreus) and crested porcupines (Hystrix cristata) were nocturnal, Menelik bushbucks (Tragelaphus scriptus meneliki) were crepuscular, and the remaining species ranged from diurnal to cathemeral. Neither similar body size nor similar diet affected overlap between species pairs. However, overlap with human temporal activity was low for Menelik bushbucks (Δ=0.45) and common duikers (Sylvicapra grimmia) appeared to become less active at stations with high human use. For carnivores, leopards (Panthera pardus) and honey badgers (Mellivora capensis) were crepuscular, and the remaining species were nocturnal. I found evidence that carnivores overlapped less when they were more similar in body size to other carnivores (average Δ=0.67-0.71) compared to species more dissimilar in body size (average Δ=0.75), although there was variation across species. In general, carnivores overlapped much less with humans (average Δ=0.20) than did herbivores (average Δ=0.52) and omnivores (average Δ=0.43). Spotted hyenas (Crocuta crocuta), in particular, appeared to alter activity to reduce overlap with humans. This study provides baseline information on presence, distribution, and activity of large- and medium-sized terrestrial and arboreal mammals in an understudied biodiversity hotspot. My findings are concerning for biodiversity conservation as rare and endangered species (e.g., mountain nyalas (Tragelaphus buxtoni), Ethiopian wolves (Canis simensis)) were rarely or never photographed, and larger carnivores (e.g., lions (Panthera leo), leopards, jackals), generally had low capture rates. The species with higher capture rates, occupancy, and activity tended to be those that can tolerate or take advantage of human activity and disturbance. Species sensitive to human disturbance eventually may be lost unless measures can be put in place to reduce human impacts. This baseline knowledge is important for future studies examining trends in mammalian wildlife populations, such as site extinction and colonization, or changes in overlap with humans, in a landscape that is continuing to experience human-caused, landscape change. / Master of Science / Harenna forest, which is located in Bale Mountains National Park, Ethiopia is an important habitat to both wildlife and people. However, it faces a number of challenges as a result of population growth leading to increased coffee farming and livestock grazing resulting in reduced habitat for wildlife species. I used 48 cameras located across the forest to record presence of terrestrial mammals and document their distribution and daily activity across the landscape. I also used data such as vegetation indices, elevation, and distances to human-disturbed areas to determine what influenced wildlife species. Cameras recorded 26 species of mammals. I had enough data to determine distribution for 13 species and daily activity for 14 species. I found that presence across the landscape and activity of herbivores and omnivores was generally higher than that of carnivores. Additionally, I found that human activity or disturbance often had a positive influence on herbivore and omnivore distribution, but my ability to detect species in camera traps was primarily influenced by habitat or landscape features. Carnivore distribution on the landscape was not influenced much by humans or habitat, but their detectability was often positively influenced by presence of humans. In addition to daily activity, I also analyzed overlap in activity between species pairs and between species and humans, to determine whether wildlife changed their temporal activity to overlap less with similar sized competitors or in response to high human use. For herbivores and omnivores, I found that tree hyraxes and crested porcupines were active at night, Menelik's bushbucks were active at sunrise and sunset, and cape bushbucks, common duiker, olive baboon, bushpig, and giant forest hogs were active either during the day or throughout the day and night. I found little evidence that the herbivores or omnivores avoided each other temporally and only the Menelik bushbuck and duiker appeared to avoid humans. For carnivores, I found that leopards and honey badgers were active early morning and evening, and the common genet, African civet, white-tailed mongoose, and spotted hyenas were all active at night only. Carnivores generally overlapped less with humans than herbivores and omnivores. I found some evidence that carnivores more similar in body size had lower temporal overlap with each other and that spotted hyaenas appeared to avoid activity during times of day when humans were active. My study not only provides baseline information on terrestrial and arboreal mammals present in Harenna forest, Ethiopia, but is also necessary for understanding how wildlife species use the landscape and particularly how presence of humans influences wild animal behavior. My findings are concerning for biodiversity conservation because I had few to no photographs, respectively, of the endangered mountain nyala and Ethiopian wolf. In fact, most of the species with a wide distribution on the landscape, or with high activity, were common or smaller species that are tolerant of, or could take advantage of, human disturbance. Without concerted effort to curtail the current landscape change caused by humans, the area is likely to lose species less tolerant of humans, and biodiversity will ultimately decline.

This thesis analyzes factors affecting adoption of integrated pest management (IPM) techniques by Kenyan vegetable farmers, including the role of their risk preferences. It also analyzes factors affecting their pesticide applications and expenditures. A survey was administered to 450 Kenyan vegetable growers to identify their pest management practices, and a behavioral experiment was run to elicit their risk preferences utilizing. Cumulative Prospect Theory. Loss aversion was found to be correlated with higher likelihood of IPM adoption while risk aversion was associated with higher pesticide application rates and expenditures. The influence of IPM adoption on pesticide use differed by IPM technique. / Master of Science / Integrated Pest Management (IPM) techniques can improve small holder farmers' livelihoods by lowering production costs and decreasing dependence on chemical pesticides. Even though some IPM techniques have been available to Kenyan vegetable farmers since the 1990's, IPM adoption remains relatively low while chemical pesticide use remains high. A farm-household survey and behavioral experiment were conducted to identify factors that influence farmer decisions to adopt IPM and to apply pesticides. Factors that influence IPM adoption were found to differ from those that influence pesticide decisions. Furthermore, IPM adoption by Kenyan farmers does not decrease use of chemical pesticides for all IPM techniques.