2015 MU theses - Freely available online
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Item Linking wetland management decisions to secretive marsh bird habitat use during spring migration and summer breeding on public wetlands in Missouri(University of Missouri--Columbia, 2015) Hill, Evan B.; Webb, Elizabeth B.Dynamic occupancy modeling was used to determine how SMB occupancy and colonization and extinction probabilities were influenced by wetland management practices, including the duration and initiation date of spring water-level drawdowns, and associated wetland habitat characteristics. The top occupancy model for sora included drawdown duration, and the top colonization/extinction model included vegetation density and percent of a site containing emergent vegetation. The top American bittern occupancy model included drawdown duration, and the top colonization/extinction model included vegetation-water interspersion. The top Virginia rail occupancy model was the null model, and the top colonization/extinction model included the range of water depths and range of vegetation heights. The top occupancy model for least bittern included drawdown initiation date and the top colonization/extinction model included average water depth. Logistic regression, logistic exposure, and discrete choice were used to determine effects of hydrologic management and habitat characteristics on habitat selection and the daily survival rate (DSR) of breeding least bittern on public wetlands in Missouri at two scales: the entire wetland and the nest point. The percent of a wetland covered in emergent vegetation and the average water depth were positively associated with probability of use at the wetland scale. At the point scale, discrete choice was used to evaluate models composed of combinations of covariates thought to influence least bittern nest site selection. The relative probability of use was positively correlated with water depth, percent of a site in emergent vegetation, and negatively correlated with vegetation density. DSR was positively correlated with average water depth at nest points.Item Atypical MVT, Zn-Cu-rich mineralization in the lower portion of the Bonneterre Dolomite, Viburnum Trend, southeast Missouri, U.S.A.(University of Missouri--Columbia, 2015) Cavender, Brittany Danielle; Shelton, Kevin L.Mississippi Valley-type (MVT) deposits of the Viburnum Trend are typically lead-dominant (Pb:Zn > 5) and occur mainly in the reef-grainstone facies of the upper Bonneterre Dolomite (Cambrian). Recent drilling has encountered economic mineralization within the lower Bonneterre Dolomite and underlying Lamotte Sandstone, more than 30 m below the main ore-bearing horizon of the district. In one area of the Brushy Creek mine, a currently mined orebody of this Zn-Pb-Cu-(Co-Ni)-rich mineralization comprises a resource of more than 250,000 tonnes containing > 14% Zn + Pb. The lower ores in the Brushy Creek mine are not related to obvious stratigraphic controls, such as pinch-outs of the Lamotte Sandstone against Precambrian knobs, and do not fit into the traditional exploration models for the Viburnum Trend. This study investigates the relationship of this unusual lower orebody at Brushy Creek mine to the typical, overlying MVT deposits of the Viburnum Trend through a combination of petrographic, cathodoluminescence, fluid inclusion, and stable isotope studies. The lower ore mineralization contains discernible zoning with increasing distance above the Lamotte Sandstone of multiple, dominantly early generations of Ni-Co-, Cuand Zn-bearing sulfides that were frequently brecciated and successively overprinted by later mineralization, including main stage Pb-Zn mineralization. The breccia is composed dominantly of sulfides supported by clay (insoluble residue) resulting in massive, high-grade ore with only rare gangue minerals. Cathodoluminescence microscopy reveals that the ore is associated with two generations of dolomite cement, early LOZ Bright and later LOZ Moderate that appear to pre-date the regional dolomite cement associated with main stage Pb-Zn mineralization in the Viburnum Trend. Microthermometry in the lower ore body yields a wide range of temperatures and salinities compared to the data from more typical deposits of the Viburnum Trend. Each stage of the sphalerite paragenesis in the lower orebody displays specific salinities and Th values across the paragenesis. Dolomite cements indicate higher Th values and largely lower salinities than the data from the regional 4-zone dolomite cements. The range of salinities and the higher temperatures of the lower ore zone cements and some of the sphalerites, especially schalenblende, emphasize that there are multiple distinct fluids, including high-temperature fluids, involved in the deposition of the lower orebody. Fluid inclusion LA-ICP-MS analysis of sphalerite-hosted fluid inclusions indicates that the lower orebody records greater atomic ratios of K/Na and Mg/Na than those published for the Viburnum Trend, and elevated ranges of Sr/Na and Ba/Na. Thus, the fluids are overall geochemically distinct from those that formed the upper orebodies. Paragenetic trends distinguish multiple fluids with distinct compositions and reflect possibly different migration pathways that varied with time. Carbon and oxygen isotope studies of the lower ore zone dolomite cements identified by cathodoluminescent studies found that the earlier of the two, LOZ Bright, has an isotopic signature unique from the later dolomite cement in the lower ore zone--LOZ Moderate--and from those of the individual zones of the regional, 4-zone cement, likely reflecting a different fluid source. Additionally, the lower ore zone cements and their calculated [delta]18Owater values show that the paragenetic trend of decreasing [delta]18O values from LOZ Bright to LOZ Moderate is not due to temperature effects, but instead indicates that the dolomite cement-depositing fluids are distinct from each other and from the fluids responsible for the regional 4-zone cements of the Viburnum Trend formed. The lower ore zone shows variations of [delta]34S values that indicate the presence of multiple sulfur sources whose influence varied with depth and time. This further illustrates that the lower orebody at Brushy Creek mine did not form from a single evolving fluid or a constant fluid mixture, but is instead the product of multiple fluids with distinct and evolving sources, which mixed at the site of deposition. This study indicates that fault activity enhanced porosity and permeability, via brecciation, thus promoting voluminous dissolution of carbonate rock. Faults localized multiple, metal-bearing fluids and sulfur sources in the same place, and the localization permitted mixing of distinct fluids that resulted in the accumulation of unique, high-grade ores at the Bonneterre Dolomite-Lamotte Sandstone contact in the Brushy Creek mine. These faults tapped into local fluid reservoirs that interacted with basement rocks prior to the onset of regional flow in southeast Missouri. This structural control reflects the importance of fault and fracture networks to ore formation in the Viburnum Trend and southeast Missouri.Item Working hard or hardly working : career-related magazine headlines and their relation to anxiety in female readers(University of Missouri--Columbia, 2015) Maggiore, Natalie; Fennell, JohnCareer‐related headlines are making their way on to the covers of prominent women's magazines. Publications such as Cosmopolitan and Glamour are working to devote more cover space to the many sub-categories of the working world: pay raises, in-office relationships, achieving success and more. With this change, comes the necessity of understanding how readers interact with and are affected by the headlines. Because research on appearance‐related headlines has proven to cause a number of negative responses in women, such as anxiety, it was important to understand if career‐related headlines would do the same. 12 women between the ages of 20 and 29 were interviewed and asked questions based on two lists of headlines from the two magazines listed above, spanning the past three years, as well as a number of corresponding articles. What emerged was an understanding that career‐related articles can, in fact, produce the same negative responses as those researched before them, though actual action is debatable. The continued purchasing, despite these negative emotions, helps further explain the function of the sociocultural theory in our society and the continued success of the magazine industry.Item Picture perfect : representing Argentina, Chile and Uruguay in AFAR, National Geographic Traveler and Travel + Leisure, 2011-2015(University of Missouri--Columbia, 2015) Lewis, Allison; Hudson, BerkleyIn a visually driven world, photographs are an imperative part of communication, especially in travel magazines. Over the past decade, only one qualitative study has been completed on images in leisure travel magazines. In 2013, Hsu and Song studied the top six Chinese leisure travel magazines to see if any patterns regarding photographic representation of Hong Kong and Macau existed. Using Beerli and Martín’s (2004) nine qualitative classification categories, they found that certain characteristics were represented while others were not. This qualitative study explored the photographic representation of Argentina, Chile and Uruguay in three American print leisure travel magazines. Following Beerli and Martín’s (2004) qualitative research template, the study reviewed 230 images published in AFAR, National Geographic Traveler and Travel + Leisure from 2011 to 2015. Evidence concluded that most images focused on three categories: Culture, History and Art; Tourist Infrastructure; and Social Environment. Findings suggest there is a restricted selection of photographs available to travel publications due to magazine budget limitations and a small number of photographers who travel to Argentina, Chile and Uruguay.Item Does sex really matter? : the cognitive and emotional effects of sexual explicitness in video advertisements(University of Missouri--Columbia, 2015) Flaker, Lauren; Bolls, Paul David, 1966-The purpose of this study was to examine how variations in explicitness of sexual visual imagery in video ads impact the way young adults cognitively and emotionally process advertising. Experimentation included a psychophysiological assessment of skin conductance and heart rate, as well as self-report measures. Skin conductance was used to measure arousal while heart rate measured cognitive resources allocated to encoding, or attention. Self-report measures covered brand recognition, arousal, likeability, pleasantness and unpleasantness. Physiological results were significant for arousal and attention change over time, with moderate sexual explicitness earning the highest skin conductance and heart rate levels. Brand recognition, however, was greatest for low sexual explicitness. These results suggest to advertising industry specialists that, while sex has the ability to increase arousal and attention of consumers, it doesn't necessarily increase brand awareness.