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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: 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: Factors to consider in the indoor environment when evaluating the risk of human health at the environmental detection limit
Creator: Herzog, Amanda Blair
Date: 2014
Collection: Electronic Theses & Dissertations
Description: Quantitative analysis of the limit of detection, sample recovery efficiency (SRE) and characterization of the microbial community are necessary parameters for accurate exposure assessment as part of the quantitative microbial risk assessment framework for indoor environments. To control and remediate an indoor environment from an outbreak, accidental or intentional release of pathogens can be a challenging task. Without understanding the situation in quantitative terms, determination of a...
Show moreQuantitative analysis of the limit of detection, sample recovery efficiency (SRE) and characterization of the microbial community are necessary parameters for accurate exposure assessment as part of the quantitative microbial risk assessment framework for indoor environments. To control and remediate an indoor environment from an outbreak, accidental or intentional release of pathogens can be a challenging task. Without understanding the situation in quantitative terms, determination of a site as safe or "clean" especially when a sample result is negative will be unachievable. The negative result may not establish zero risk and can be due to variability in the sampling or detection methods. The release of Bacillus anthracis in 2001, the numerous outbreaks from the food industry, hospital settings, and on university campuses have highlighted the lack of quantitative information. A review of the literature for the limits of detection of methods detecting B. anthracis provided a distribution to quantify the variability in the instrument limit of detection; however there were only a few articles on the environmental limit of detection. An exponential dose response model estimated the risk at the dose equal to the environmental limit of detection to determine the probability of death as high as 0.52. The SRE of bacteriophage P22 was evaluated at the environmental limit of detection and was most affected by sampling time, fomite surface area, wetting agent and relative humidity. After samples dried on the fomite (20 min), less than 3% was able to be recovered even though the bacteriophage P22 was still active on the fomite. Genetically characterizing the bacterial communities on touched and untouched fomites resulted in two unique bacterial communities. Touched fomites were more diverse and had a high presence of fecal indicators which demonstrated potential reservoirs for pathogens. This research will improve exposure assessment by indicating the risk and limitations at the environmental limit of detection, enhancement of sampling strategies and the role fomites have in the transmission of infectious diseases.
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Title: Measurement invariance of a summative achievement assessment over time : is status really ready for growth
Creator: Viger, Steven Guy
Date: 2014
Collection: Electronic Theses & Dissertations
Description: The current study investigates the phenomenon of measurement invariance by examining the construct stability of a summative mathematics achievement instrument over time gleaned from an existing data set. In doing so, not only is the general question of measurement invariance of the particular instrument addressed, but also in the context of growth studies. The onus of the study as well as the results are presented in light of the current political context of large scale K-12 assessment and...
Show moreThe current study investigates the phenomenon of measurement invariance by examining the construct stability of a summative mathematics achievement instrument over time gleaned from an existing data set. In doing so, not only is the general question of measurement invariance of the particular instrument addressed, but also in the context of growth studies. The onus of the study as well as the results are presented in light of the current political context of large scale K-12 assessment and the shifting of emphasis from status to growth. As the reader will discover, great pressure is placed on results not necessarily intended to serve as the metric required by policy. The results and implications are framed in both measurement and practical contexts.
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Title: Surface energy characterization and competitive surface equilibria using contact angle
Creator: Stubbs, Barrack Perez
Date: 2017
Collection: Electronic Theses & Dissertations
Description: Surface energy measurements are usually difficult to assess when not considering a solid-air or liquid-air interface. Contact angles was used as a method of obtaining the interfacial energy of a silanol-water surface using carbon tetrachloride as a probing liquid. The theory for this work operated under the assumption that the pKa of a silanol surface could be measured by obtaining a titration like curve as a function of pH. A decrease in contact angle of about 7° was observed at a pH (pKa)...
Show moreSurface energy measurements are usually difficult to assess when not considering a solid-air or liquid-air interface. Contact angles was used as a method of obtaining the interfacial energy of a silanol-water surface using carbon tetrachloride as a probing liquid. The theory for this work operated under the assumption that the pKa of a silanol surface could be measured by obtaining a titration like curve as a function of pH. A decrease in contact angle of about 7° was observed at a pH (pKa) of 3.5. This corresponds to an energy difference of 2 mN/m. -- Abstract.
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Title: Studies of the microwave instability in the small isochronous ring
Creator: Li, Yingjie (Of Michigan State University)
Date: 2015
Collection: Electronic Theses & Dissertations
Description: "This dissertation is devoted to deepening our knowledge and understanding of the hidden physics regarding the microwave instability of the space-charge dominated beams in the small isochronous ring, which was observed in our previous numerical and experimental studies." -- Abstract.

Title: Shock and vibration in the rail environment : trailor-on-flat car and container-in-well car
Creator: Goodwin, Daniel Lee
Date: 1988
Collection: Electronic Theses & Dissertations

Title: Relationship among motor skill development, aerobic capacity, body composition, and perceived competence of fourth grade school children
Creator: Kelly, Sheila Kathleen
Date: 2010
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: Designing a package for pharmaceutical tablets in relation to moisture and dissolution
Creator: Yoon, Seungyil
Date: 2003
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: 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: Investigating blood flow and antibiotic dosing using traditional microfluidics and novel 3D printed devices
Creator: Meisel, Jayda Erkal
Date: 2015
Collection: Electronic Theses & Dissertations
Description: Over the last 25 years, it has been established that the red blood cell (RBC) is a major determinant in blood flow, which it can modulate through release of adenosine triphosphate (ATP). Although RBCs store intracellular ATP in mM concentrations, measurements indicate that the cells release nM concentrations when stimulated by deformation, hypoxia (lowered oxygen tension), or incubation with pharmacological stimuli such as hydroxyurea (HU), which is the only approved drug for treatment of...
Show moreOver the last 25 years, it has been established that the red blood cell (RBC) is a major determinant in blood flow, which it can modulate through release of adenosine triphosphate (ATP). Although RBCs store intracellular ATP in mM concentrations, measurements indicate that the cells release nM concentrations when stimulated by deformation, hypoxia (lowered oxygen tension), or incubation with pharmacological stimuli such as hydroxyurea (HU), which is the only approved drug for treatment of sickle cell disease. Upon release, RBC-derived ATP can induce vessel dilation via activation of endothelial cell nitric oxide synthase (eNOS) to produce nitric oxide (NO). To probe the fate of increased ATP release from human RBCs incubated with the drug hydroxyurea, a traditional soft polymer platform was utilized to facilitate measurement of cell-to-cell communication between RBCs and a cultured endothelium. This device contained an array of micron-scale channels through which RBC samples were pumped. The sample flow was separated from a detection well by a porous polycarbonate membrane. Stimulated ATP released from the RBCs diffused across the membrane to the detection wells and was measured using the luciferin-luciferase chemiluminescence assay, integrated with a plate reader for detection. RBCs incubated with 100 uM of HU released on average 2.06 ± 0.37 times more ATP relative to the control sample. Through the use of various inhibitors, this increase in ATP release was subsequently demonstrated to depend on RBC deformability, RBC NOS activity, and the cystic fibrosis transmembrane conductance regulator protein (CFTR). The fate of the measured RBC-derived ATP was also investigated by probing ATP signalling to an adjacent cultured endothelium.ATP release from RBCs increases in response to hypoxia, or lowered oxygen tension; however, the dependence of RBC ATP release on oxygen tension has not been investigated. To enable measurement of RBC ATP release and oxygen tension in a flowing stream of RBCs, a 3D printed device was designed to accomodate commercial transwell inserts for ATP measurements, as well as threaded Clark-type electrodes for amperometric oxygen measurements. The device consisted of a channel 2 mm wide and 0.5 mm in height with two ports for analyte detection and one threaded port for an electrode. The Clark-type electrode was fabricated from gold and silver wires secured into a finger tight fitting. Oxygen standards and RBC samples were prepared using air and argon purged buffers. Using the 3D printed device, RBC ATP release and oxygen tension were measured simultaneously from prepared RBC samples. Relative to controls, RBC ATP release increased significantly in response to systematically lowered oxygen tension with a maximum increase of 2.38 ± 0.43 fold more ATP when exposed to 5.35 ± 0.12 ppm oxygen. ATP release saturated, i.e., was not significantly different, at lower oxygen tensions. This increase in ATP release was inhibited by incubating RBCs with the cell stiffening agent, diamide. The dependence of hypoxic RBC ATP release on the conformation of heme in hemoglobin (Hb) is demonstrated by converting measured oxygen tensions to Hb saturation.The 3D printed platforms presented herein were also utilized as in vitro tools to model pharmacokinetic dosing profiles, specifically with applications for studying antibiotic resistance. The World Health Organization, Centers for Disease Control, and the White House have issued reports that outline strategies to combat antibiotic resistance. The Spence lab has developed a 3D printed device to mimic in vivo drug dosing profiles on an in vitro platform for applications in drug discovery. This 3D printed diffusion-based dynamic dosing device mimics the dosing capabilities of the hollow fiber chamber reactor (HFCR). The in vitro 3D printed device contains 6 ports to house commercial polyester transwell membrane inserts (0.4 micron) and in house fabricated 0.2 micron pore size inserts (polyester), which can be loaded with a sample of Escherichia coli. Chemically competent, kanamycin resistant E. coli were dosed with the DNA gyrase and topoisomerase IV inhibitor levofloxacin, which reached a maximum concentration (Cmax) of 21.0 ± 5.7 uM (0.4 micron pore size) and 68.0 ± 7.1 uM (0.2 micron pore size) of levofloxacin in approximately 1 hour. After dosing, the viability of the bacteria samples was measured using standard plating methods.
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Title: Effects of design parameters on a single-lap, bolted joint; using internal and surface strain measurement techniques
Creator: Woodruff, John
Date: 2011
Collection: Electronic Theses & Dissertations
Description: Composite materials have emerged as a method of engineering high strength structures to specific tasks at a low weight cost. The strength to weight ratio makes composite materials ideal for replacing metal components in vehicles, but the plates have to be thick enough to withstand impacts during service use. Often, the weakest point of any composite panel is the point at which it is fastened to the vehicle frame. A bolting method is identified as the fastening mechanism of choice and is...
Show moreComposite materials have emerged as a method of engineering high strength structures to specific tasks at a low weight cost. The strength to weight ratio makes composite materials ideal for replacing metal components in vehicles, but the plates have to be thick enough to withstand impacts during service use. Often, the weakest point of any composite panel is the point at which it is fastened to the vehicle frame. A bolting method is identified as the fastening mechanism of choice and is applied to a single-lap joint geometry for this study. Fastening parameters included bolt-to-hole clearance, and the use of insertsA combination of measurements taken using embedded fiber optic strain gages, digital image correlation, and stiffness data was used to determine the optimum design characteristics. It was seen that clearance had a negative effect on the stiffness of the joint, increased clearance from the zero percent clearance had an immediate effect on decreasing the stiffness of the joint. Also, the fiber optic strain gages found that there was a significant strain concentration just inside the interface between the overlap of the bolted composite to aluminum plates. Initial increase in clearance was seen to increase this concentration. Also, in studying the use of inserts it was found that an aluminum insert at the largest diameter tested of 0.75" outer diameter was the best performing geometry. Overall, the design recommendations were that there should be minimal to no clearance, with an aluminum insert with an outer diameter of 0.75".
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Title: Microbial succession on the lake sturgeon egg surface : mechanisms shaping the microbial community assembly during succession and the effect of microbial successional processes on host life history traits
Creator: Fujimoto, Masanori
Date: 2012
Collection: Electronic Theses & Dissertations
Description: Microbial community assemblages have been studied in a variety of hosts and environments. However, to date, most of the studies conducted on microbial community structure have been observational in nature. As a result, the underlying mechanisms shaping microbial community assembly at a given place and time remain largely unknown. In this study, we were particularly interested in understanding how a microbial community develops on animal hosts. As soon as eggs or neonatal organisms are exposed...
Show moreMicrobial community assemblages have been studied in a variety of hosts and environments. However, to date, most of the studies conducted on microbial community structure have been observational in nature. As a result, the underlying mechanisms shaping microbial community assembly at a given place and time remain largely unknown. In this study, we were particularly interested in understanding how a microbial community develops on animal hosts. As soon as eggs or neonatal organisms are exposed to environments, microbes colonize surfaces of eggs or the epithelium of host tissues and establish a microbial community. Such a process involving initial colonization and subsequent sequential changes in species composition is called "succession". Microbial succession is a complex process with the number of different factors involved including initial stochastic arrival of microbes at an open space via dispersal, attachment / colonization at the space, subsequent community sorting via adaptation, and continuous dispersal from neighboring spaces. In this study, we examined microbial succession on the egg surface of the Lake Sturgeon, a threatened fish species inhabiting in the Great Lakes. We sought to understand the role of both host factors (e.g. innate immunity, egg chemistry) and various environmental factors (e.g. aquatic microbes, stream flow rate and temperature) in influencing the formation of microbial communities on the egg surfaces over the course of the egg incubation period. We also sought to evaluate the effect of different microbial successional processes on host life history traits, including egg mortality and larval size at hatch. These topics were important for this system because dams constructed in the Lake Sturgeon's spawning streams can alter environmental factors such as aquatic microbes, stream flow rate, and temperature, which may in turn affect the life history of the sturgeon. To achieve these objectives, we adopted an integrative approach, which relied on manipulation of environmental factors including aquatic microbial community, aquatic microbial quantity, stream flow rate, and temperature. We also employed a combination of various analytical techniques, including 16S rRNA gene pyrosequencing, 16S rRNA based T-RFLP, 16S rRNA clone library, 16S rRNA based quantitative PCR, light and fluorescence microscopy, and culture methods. We found that egg microbial communities were distinct from source water microbial communities. Host eggs shaped egg-associated microbial communities within 60 minutes of fertilization, selecting for and against certain microbial species. In addition, the egg surface microbial communities were not constant but rather dynamic, as we observed directional changes of microbial communities along with egg developmental stages. Egg-associated microbial communities also varied with the environmental variables they were exposed to during incubation, including temperature, flow rate, and aquatic microbial community. These differences in the egg-associated microbial community composition affected host life history traits including egg mortality and larvae size at hatch. We also identified a key set of microbial species that significantly improved egg survival and could be used for probiotic treatment in this threatened fish species in the future. This study was the first microbial succession study conducted on fish eggs. Our results highlight the complexity of host-microbe-environment interactions. This study has implications for managing threatened host populations such as the Lake Sturgeon inhabiting human-altered rivers, since it demonstrates the potential effect of dams (which alter aquatic microbes and temperature) on downstream host-microbe interactions.
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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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Title: Level of distiller's grain with soluble effects on gas emissions from growing steers
Creator: Cross, Landon Drew
Date: 2011
Collection: Electronic Theses & Dissertations
Description: ABSTRACTLEVEL OF DISTILLER'S GRAIN WITH SOLUBLE EFFECTS ON GAS EMISSIONS FROM GROWING STEERSByLandon Drew Cross A rising concern with feeding high levels of distiller¡&hibar;s grain with soluble (DGS) is its high S and N content and the effects it might have on S- and N-containing emissions from gas produced in the rumen and manure. Two trials were conducted with 12 Holstein steers housed in individual environmentally-controlled rooms to monitor gas emissions. Three dietary...
Show moreABSTRACTLEVEL OF DISTILLER'S GRAIN WITH SOLUBLE EFFECTS ON GAS EMISSIONS FROM GROWING STEERSByLandon Drew Cross A rising concern with feeding high levels of distiller¡&hibar;s grain with soluble (DGS) is its high S and N content and the effects it might have on S- and N-containing emissions from gas produced in the rumen and manure. Two trials were conducted with 12 Holstein steers housed in individual environmentally-controlled rooms to monitor gas emissions. Three dietary treatments were fed in trial 1; containing 0% (control), 40%, and 60% DDGS. In trial 2, treatments were the same except the 60% DDGS dietary treatment was replaced with a 40% DDGS diet fortified with 8 ppm Mo and 90 ppm Cu, which will be referred to as 40% DDGS+. The 40% DDGS+ diet served as a potential strategy to mitigate S-containing gas emissions. Each trial was divided into 2 phases; phase 1 of each trial monitored emissions when urine and feces were collected in the same vessel. Phase 2 of each trial monitored emissions while steers were fitted with fecal bags to separate feces from urine. Distiller¡&hibar;s grain with soluble increased H₂S and NH₃ production (P < 0.05) and these emissions were decreased to undetectable levels during phase 2 of each trial compared to emissions generated in phase 1 (P < 0.01). Addition of Mo and Cu in trial 2 tended to decrease H₂S emissions when adjusted for S-intake (P = 0.08). In trial 2, the 40% DDGS+ treatment decreased CO₂ emissions (P ¡Ü 0.05) and tended to generate less CH₄ emissions compared to the control and the traditional 40% DDGS diet.
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Title: Electron diffraction
Creator: Muller, John Hubert
Date: 1954
Collection: Electronic Theses & Dissertations

Title: Nuclear structure of proton-rich intermediate mass nuclei studied with advanced lifetime measurement techniques
Creator: Morse, Christopher Scott
Date: 2015
Collection: Electronic Theses & Dissertations
Description: The transition matrix elements between excited nuclear states provide valuable information about the structure of exotic nuclei. Lifetime measurements area model-independent way to deduce these matrix elements from experimental data.Two studies of proton-rich nuclei near mass 70 are presented herein usingadvanced lifetime measurement techniques.The first study is a measurement of the $8^+_1$ and $9^+_1$ states in the odd-$N$, odd-$Z$ nucleus $^{70}$As.The lifetimes of these states were...
Show moreThe transition matrix elements between excited nuclear states provide valuable information about the structure of exotic nuclei. Lifetime measurements area model-independent way to deduce these matrix elements from experimental data.Two studies of proton-rich nuclei near mass 70 are presented herein usingadvanced lifetime measurement techniques.The first study is a measurement of the $8^+_1$ and $9^+_1$ states in the odd-$N$, odd-$Z$ nucleus $^{70}$As.The lifetimes of these states were determined by the application of the $\gamma$-ray lineshape method to $\gamma$-$\gamma$ coincidence data.The states were populated using with the $^9$Be($^{78}$Rb,$^{70}$As) reaction and$\gamma$ rays were detected with the Segmented Germanium Array in coincidencewith reaction products detected in the focal plane of the S800 Spectrograph.The $B(E1;8^+\rightarrow7^-)$ and $B(M1;9^+\rightarrow8^+)$ transition strengthswere deduced and were found to support the assignment of these states to a coupling of the odd proton and neutron in the $g_{9/2}$ orbital.The second study is a measurement of the $2_1^+$ state lifetime in the $N=Z$nucleus $^{74}$Rb. A novel technique called the Differential Recoil DistanceMethod was used to extract the lifetime from the $\gamma$-ray spectra. The next-generation $\gamma$-ray detector array GRETINA was used in theexperiment, again coupled to the S800 Spectrograph to detect residues from $^9$Be($^{74}$Kr,$^{74}$Rb) charge exchange reactions. The $B(E2;2^+_1\rightarrow0^+_1)$ strength was calculated and is consistent with the measured strength of the transition between the isobaric analogue states in $^{74}$Kr, which may be a signature of shape coexistence in $^{74}$Rb.
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Title: Minimum distance measurement errors model fitting
Creator: Song, Weixing
Date: 2006
Collection: Electronic Theses & Dissertations

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