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Title: A NARR derived low-level jet climatology over North America
Creator: Doubler, Dana L.
Date: 2013
Collection: Electronic Theses & Dissertations
Description: Previous climatological studies of low-level jets (LLJs) have been restricted to individual geographic regions. In this study, an expanded climatology of the characteristics of northerly low-level jets (N-LLJs) and southerly low-level jets (S-LLJs) is provided for North America and nearby coastal areas to better document the spatial variations of these important mesoscale circulation features. In addition, time of initiation and persistence of S-LLJ events in central North America and over...
Show morePrevious climatological studies of low-level jets (LLJs) have been restricted to individual geographic regions. In this study, an expanded climatology of the characteristics of northerly low-level jets (N-LLJs) and southerly low-level jets (S-LLJs) is provided for North America and nearby coastal areas to better document the spatial variations of these important mesoscale circulation features. In addition, time of initiation and persistence of S-LLJ events in central North America and over the Gulf of Mexico are analyzed. The North American Regional Reanalysis (NARR), with a 32-km horizontal resolution and a 3-hourly temporal resolution, was used to analyze (by time of day, month, season and year) the frequency, height above ground level, and wind speed of LLJs, and, for S-LLJs in central North America only, diurnal and seasonal variations in the time of initiation and duration jet events. The spatial analyses highlight well-known wind maxima but also point to previously-unknown locations that experience frequent jet-like wind maxima. The analyses also suggest that boundary-layer forcing is important for S-LLJ occurrence, including S-LLJs that form at high latitudes in summer and those that form in the central and southern plains in winter. The NARR-derived analyses supplement and enhance the understanding of the climatological characteristics of low-level wind maxima across North America and coastal environs. The findings also highlight that many aspects of low-level wind maxima remain incompletely understood and point to the need for considerable further research on the processes contributing to jet formation.
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Title: A direct measurement of intensities in a Fresnel diffraction pattern
Creator: McClellan, Cyril Elwin
Date: 1938
Collection: Electronic Theses & Dissertations

Title: A modified "shift-and-ratio" method for extraction of the effective channel length of devices containing halo-implants
Creator: Argandoña, Jorge Walter
Date: 2004
Collection: Electronic Theses & Dissertations

Title: A new method for the visualization and measurement of ultrasonic fields
Creator: Bennett, Grant S.
Date: 1952
Collection: Electronic Theses & Dissertations

Title: A nonconventional morphometric technique for measuring ontogenetic shape changes in two species of centrarchid fishes
Creator: Zablotny, James E. (James Edward)
Date: 1989
Collection: Electronic Theses & Dissertations

Title: A rheological model of apple flesh failure during the Magness-Taylor puncture test
Creator: Jeong, Sanghyup
Date: 1997
Collection: Electronic Theses & Dissertations

Title: A stochastic multi-scale model of stream-groundwater interaction in strongly heterogeneous porous medium and its application in southern Branch County, Michigan
Creator: Xinyu, Ye
Date: 2014
Collection: Electronic Theses & Dissertations
Description: In this paper, stream depletion is assessed by the approach of multi-scale geostatistics in stressed watershed, South Branch County, Michigan. The watershed is currently under large water demand and representative of the general failure to pass the online Water Withdrawal Assessment Tool. Due to the heterogeneity of porous medium and the high variability of hydrogeological parameters and scale, there is a deviation between field observations and simulated groundwater flow in those areas. The...
Show moreIn this paper, stream depletion is assessed by the approach of multi-scale geostatistics in stressed watershed, South Branch County, Michigan. The watershed is currently under large water demand and representative of the general failure to pass the online Water Withdrawal Assessment Tool. Due to the heterogeneity of porous medium and the high variability of hydrogeological parameters and scale, there is a deviation between field observations and simulated groundwater flow in those areas. The approach of multi-scale geostatistics model based on detailed lithological data and its application in numerical groundwater simulation can be used in stream depletion assessment. Specifically, the multi-scale transition probability geostatistics approach, supplemented with a 10m Digital Elevation Model, allows for a more realistic integration of heterogeneous medium into the development of correlated spatial variability of hydrogeological parameters at each spatial scale. This approach enables accurate simulation of complex hydrogeology, including vertical shift structural variation and aquifer thickness variations. Systematic hydrology models at the regional, local and site scale allows for simulations of integrated water budget analysis. These simulations are necessary to evaluate the water depletions of targeted streams and the surrounded protected area. The hydrology system is calibrated with the steady state water levels from 732 monitoring wells.The stability of transition probability geostatistics model depends on the distributions, the heterogeneity of simulated area and other factors. The results show that transition probability geostatistics model provides a reasonable distribution of materials in aquifer medium, improving numerical groundwater modeling in assessing water depletion in streams and venerable area.
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Title: A time to forget : circadian and cognitive costs of nocturnal activity for a diurnal brain
Creator: Martin-Fairey, Carmel Annette
Date: 2014
Collection: Electronic Theses & Dissertations
Description: A TIME TO FORGET: CIRCADIAN AND COGNITIVE COSTS OF NOCTURNAL ACTIVITY FOR A DIURNAL BRAIN.ByCarmel Annette Martin-FaireyEntrainment of circadian rhythms to the day-night cycle serves to maintain appropriate relationships between behavioral and physiological processes and the external environment. In today's 24hour society, the newly attained capability to be active around the clock has challenged the body's ability to maintain entrainment to the day-night cycle. Humans, who are chronically...
Show moreA TIME TO FORGET: CIRCADIAN AND COGNITIVE COSTS OF NOCTURNAL ACTIVITY FOR A DIURNAL BRAIN.ByCarmel Annette Martin-FaireyEntrainment of circadian rhythms to the day-night cycle serves to maintain appropriate relationships between behavioral and physiological processes and the external environment. In today's 24hour society, the newly attained capability to be active around the clock has challenged the body's ability to maintain entrainment to the day-night cycle. Humans, who are chronically active at night, have a higher risk for physiological and psychological pathologies, including a reduction in cognitive abilities. Investigations to improve our understanding of the neural underpinnings of the pathologies associated with nocturnal activity in humans have been stunted by the lack of a diurnal animal model and by the use of forced-activity paradigms. The experiments in this dissertation address these issues with the use of a diurnal mammalian model, the grass rat (Arvicanthis niloticus), that has the propensity to shift voluntarily its activity to match that of a nocturnal mammal.In the first set of experiments, the adoption of a nocturnal profile by grass rats resulted in a phase reversal of the rhythmic expression of clock genes in the hypothalamic paraventricular nucleus, but with no disruption of the nocturnal rise in plasma melatonin levels. These differences in the phase of clock gene expression, but not in the nocturnal rise in melatonin, indicate that nocturnal activity in a diurnal species is disruptive of some rhythmic processes, while others appear insensitive to such disruptions. In the second set of experiments, the Morris water maze (MWM) was used to investigate the optimal phase of retention for a hippocampal dependent task in sedentary diurnal grass rats. The rhythmic expression of plasticity gene products in areas important for learning and memory was also monitored. The optimal phase for long-term retention of a hippocampal task was found to be out of phase with that of the nocturnal lab rat. No time-of-testing effects were found for the acquisition curve or for short-term retention of the task, as previously reported for nocturnal lab rats. Plasticity gene product rhythms showed peak expression during the light phase in grass rats, while peak expression for nocturnal lab rats has been reported to occur in the dark phase. In the third set of experiments, the night-active grass rat was utilized as a model for understanding the cognitive deficits associated with nocturnal activity in humans. While the overall learning curve for the MWM did not show time-of-training or chronotype differences, the night active grass rat exhibited dramatic deficits in both short-and long-term retention. There was a chronotype difference in the phase of the rhythm of hippocampal expression of only one of two plasticity gene products. In the hippocampus cFOS expression was affected by chronotype only in the CA1. These observations indicate that nocturnal activity disrupts the circadian regulation of key hippocampal functions. Thus, circadian desynchrony in the hippocampus may be responsible for the cognitive deficits seen in humans who choose to be active at night. Taken together the present work links voluntary activity during the rest phase in a diurnal species to physiological and cognitive pathologies, and argues against the claim that mammalian chronotype is a completely malleable trait of the circadian system.
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Title: Absolute intensity measurements of Fresnel diffraction patterns
Creator: Woodward, J., Guy
Date: 1938
Collection: Electronic Theses & Dissertations

Title: Aflatoxin levels in sunflower seeds, cakes, and crude oil sediments locally produced in Tanzania and potential phytochemicals for aflatoxin management
Creator: Mmongoyo, Juma Abdallah
Date: 2016
Collection: Electronic Theses & Dissertations
Description: This dissertation had two objectives. The first was to determine total aflatoxin concentrations in sunflower seeds, cakes and crude oil sediments from small-scale oil processors across Tanzania. The towns selected for sunflower sample collection included Mbeya, Iringa, Morogoro, Dodoma, Singida, Babati-Manyara and Karatu-Arusha. We collected a total of 232 samples: sunflower seed (n = 90), cake samples (n = 92) and crude sunflower oil sediments (n = 50) across two years, which were analyzed...
Show moreThis dissertation had two objectives. The first was to determine total aflatoxin concentrations in sunflower seeds, cakes and crude oil sediments from small-scale oil processors across Tanzania. The towns selected for sunflower sample collection included Mbeya, Iringa, Morogoro, Dodoma, Singida, Babati-Manyara and Karatu-Arusha. We collected a total of 232 samples: sunflower seed (n = 90), cake samples (n = 92) and crude sunflower oil sediments (n = 50) across two years, which were analyzed for total aflatoxin concentrations using a direct competitive enzyme-linked immunosorbent assay (ELISA). The aflatoxin surveillance performed in June-August 2014, indicated that the highest aflatoxin levels in sunflower seeds were from the towns of Babati-Manyara, Singida, and Dodoma. The aflatoxin levels in sunflower cakes were exceedingly high in Singida, Dodoma, and Mbeya. The surveillance performed in August-October 2015, indicated that the highest aflatoxin concentrations in sunflower seeds were from Mbeya, Singida, and Morogoro. Singida, Dodoma, and Morogoro had shown unacceptable aflatoxin levels in sunflower cakes. Aflatoxin levels in oil sediments were considerably lower in both years except Morogoro, which showed two oil sediments exceedingly contaminated (41.7 and 85.3 ng/g). Concerning risk assessment, Dodoma and Babati-Manyara showed dietary exposures of 25 and 21 ng/kg bw/day, respectively, for sunflower seed consumption in 2014. Liver cancer risks for these exposures were 0.9 and 0.8 cases per year per 100,000 individuals, respectively. Samples from Morogoro suggested dietary exposure of 24 ng/kg bw/day for sunflower seed consumption in 2015 that carried a risk of 0.9 cases per year per 100,000 individuals. Although the crude oil sediment data showed that crude oils were safe, the general results of aflatoxin levels in seeds and cakes particularly from Manyara, Singida, Dodoma and Morogoro, and crude oil sediments from Morogoro, indicate that there is a potential risk of exposure to aflatoxin through sunflower products and intervention strategies are required. Our second objective was to determine the anti-aflatoxigenic properties of compounds from a traditional medicinal plant D. mafiensis root bark against vegetative growth, sporulation and aflatoxin production by Aspergillus flavus and Aspergillus parasiticus. The bioactive compounds diosquinone (DQ) and 3-hydroxydiosquinone (3HDQ) were elucidated and identified using 1H- and 13C-NMR and LC-MS methods. Growth inhibition was determined by measuring the colony diameters of the molds in culture. Total aflatoxin was quantified by direct competitive enzyme-linked immunosorbent assay (ELISA). DQ showed weak potency against A. flavus and A. parasiticus vegetative growth (MIC50 >100 μg/mL), and 3HDQ demonstrated a strong potency against A. flavus (MIC50 = 14.9 μg/mL) and A. parasiticus (MIC50 = 39.1 μg/mL). Despite its weak potency against vegetative growth, DQ strongly reduced total aflatoxin production by A. flavus and A. parasiticus for over 90 %. Counterintuitively, 3HDQ stimulated aflatoxin production by A. flavus at lower doses but started to reduce aflatoxin production at the dose of 100 μg/mL. 3HDQ strongly reduced total aflatoxin production by A. parasiticus even at lower doses. In summary, DQ and 3HDQ could be used as natural fungicides to prevent mold growth and aflatoxin accumulation in food and feed.
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Title: An evaluation of the Hot-Dry-Windy fire-weather index using historical fire events and meteorological analysis datasets
Creator: Kulseth, McKenzie G.
Date: 2019
Collection: Electronic Theses & Dissertations
Description: "This study evaluates the skill of a newly developed fire-weather index called the Hot-Dry-Windy Index (HDW) using five meteorological analysis datasets for twenty-three historical fire events, and sensitivities of that skill to assumptions made in index development. The meteorological analysis datasets used in this study are the Climate Forecast System Reanalysis, the Global Forecast System, the North American Regional Reanalysis, the Rapid Update Cycle, and the North American Mesoscale...
Show more"This study evaluates the skill of a newly developed fire-weather index called the Hot-Dry-Windy Index (HDW) using five meteorological analysis datasets for twenty-three historical fire events, and sensitivities of that skill to assumptions made in index development. The meteorological analysis datasets used in this study are the Climate Forecast System Reanalysis, the Global Forecast System, the North American Regional Reanalysis, the Rapid Update Cycle, and the North American Mesoscale Forecast System. These datasets were chosen because they are widely used in weather forecast and other meteorological applications and because their data archives cover the period of historical fire events used in this study. The twenty-three historical wildland fire events were chosen to provide geographic diversity to this evaluation. The results of this study suggest that the original HDW formulation is capable of identifying the largest fire spread day for between 56.5 to 78.3% of the twenty-three wildland fire events used in this study, and that alterations to the HDW formulation do not positively impact the skill of this index. The results also indicate that inclusion of the grid points surrounding the central-grid-point containing the latitude and longitude of each fire event in the evaluation of index skill provides higher skill than when only considering the central grid point. The skill of HDW computed by the five meteorological analysis datasets vary between fires and no one dataset consistently outperforms or underperforms the others."--Page ii.
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Title: An interactionist approach to assessing personality in work contexts : construct validation of a predictor of customer service performance
Creator: Ployhart, Robert E.
Date: 1999
Collection: Electronic Theses & Dissertations

Title: Analysis of Daimler-Chrysler/ European radiated emissions testing set-up for modules
Creator: Coleman, Christopher Mark
Date: 1999
Collection: Electronic Theses & Dissertations

Title: Application and analysis of a microscope diffusion chamber
Creator: Sherban, Keith D.
Date: 1987
Collection: Electronic Theses & Dissertations

Title: Applied econometric studies in air quality and education
Creator: Khawand, Christopher
Date: 2016
Collection: Electronic Theses & Dissertations
Description: "This dissertation is comprised of three standalone chapters loosely organized around a causal inference theme. It addresses empirical questions in environmental quality and education, while also offering some methodological insight in each chapter." -- Abstract.

Title: Coastline change at four sites in Lower Michigan
Creator: Wernette, Phillipe Alan
Date: 2012
Collection: Electronic Theses & Dissertations
Description: This study tested a new method of coastline change analysis to examine coastline change at four sites along the Lower Michigan coast. Shoreline position was manually delineated from aerial photography for multiple years between 1938 and 2010. The positional uncertainty associated with each shoreline was calculated in a GIS. A new method was developed to analyze the digitized shorelines. This new method generates a buffer (epsilon band) with radius equal to the positional uncertainty around...
Show moreThis study tested a new method of coastline change analysis to examine coastline change at four sites along the Lower Michigan coast. Shoreline position was manually delineated from aerial photography for multiple years between 1938 and 2010. The positional uncertainty associated with each shoreline was calculated in a GIS. A new method was developed to analyze the digitized shorelines. This new method generates a buffer (epsilon band) with radius equal to the positional uncertainty around each shoreline and uses these buffers to visualize and test for significant change. Significant change is determined by comparing a calculated proportion of similarity to a user-defined threshold. A series of transects perpendicular to the shoreline were then used to determine the direction and magnitude of change. Results indicate that shoreline position was most dynamic at the Manistee County site, and was least dynamic at the Sanilac County site. Overall there were more pairs of years with significant shoreline change at the two west coast sites, which suggests that shoreline position is more variable at the two sites along the west coast of Lower Michigan than along the east coast of Lower Michigan. The principle advantage of this dual epsilon method is that it analyzes change along the entire shoreline. This study demonstrates that the dual epsilon band method is feasible along a tideless coast.
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Title: Communication neuroscience on a shoestring : examining electrocortical responses to visual messages via mobile EEG
Creator: Jahn, Nolan T.
Date: 2020
Collection: Electronic Theses & Dissertations
Description: Visual communication plays a crucial role in sharing relevant social information. Vision has been studied extensively in the domain of neuroscience, and visual communication has been explored through traditional social science avenues. However, the field can benefit greatly at the crossroads of communication neuroscience, similar to the intersection of biology and chemistry - biochemistry. One roadblock has been the cost and difficulty of incorporating neuroscience methods in communication...
Show moreVisual communication plays a crucial role in sharing relevant social information. Vision has been studied extensively in the domain of neuroscience, and visual communication has been explored through traditional social science avenues. However, the field can benefit greatly at the crossroads of communication neuroscience, similar to the intersection of biology and chemistry - biochemistry. One roadblock has been the cost and difficulty of incorporating neuroscience methods in communication studies. This study tested a novel electroencephalography (EEG) device that is far cheaper, easier to use, and more mobile than previous devices. The EEG system was used to compare event related potentials (ERPs) to affective visual stimuli - representative of the kinds of engaging content that pervades modern social media. While no differences were found between positive and neutral stimuli, ERPs were successfully detected by the new EEG system and the moderate strength of our affect manipulation may have precluded stronger effects. Additionally, making use of a "foot-in-the-door" compliance gaining technique in participant instructions led to significantly improved data capture. These results support the use of this EEG system in future communication studies and provides evidence for an easy social influence tactic that can improve data quality as neuroscience is being scaled up to big-data studies. Having an affordable and mobile EEG system makes it possible to incorporate neuroimaging into a variety of communication paradigms, extending beyond visual communication.
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