Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.

Thesis (M.S.)--Marquette University, 2009. / Jon D. Koch, John P. Borg, James M. Lightstone, Advisors.

Thesis (M.S.)--Ohio University, November, 2004. / Title from PDF t.p. Includes bibliographical references (p. 115-117)

Thesis (Ph.D.)--York University, 2005. Graduate Programme in Physics and Astronomy. / Typescript. Includes bibliographical references (leaves 218-233). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pNR11637

Diss. (sammanfattning) Linköping : Linköpings universitet, 2008. / Härtill 4 uppsatser.

Thesis (M.S.)--University of Texas at Dallas, 2008. / Includes vita. Includes bibliographical references (leaves 63-65)

In this thesis I study and measure the spatial distribution of galaxies selected in optical and near-infrared surveys over cosmic time. By measuring the clustering of these sources, valuable insight can be gained into the role of environment in shaping galaxy evolution over the history of the Universe. I present a series of results from a clustering analysis of the first data release of the Visible and Infrared Survey Telescope for Astronomy (VISTA) Deep Extragalactic Observations (VIDEO) survey. VIDEO is the only survey currently capable of probing the bulk of stellar mass in galaxies at redshifts corresponding to the peak of star formation on degree scales. Galaxy clustering is measured with the two-point correlation function, which is calculated using a non para- metric kernel based density estimator. I use my measurements to investigate the connection between the galaxies and the host dark matter halo using a Halo Occupation Distribution (HOD) methodology, deriving bias, satellite fractions, and typical host halo masses for stellar masses between 10^9.35M_⊙ and 10^10.85M_⊙, at redshifts 0.5 < z < 1.7. I show that the typical halo mass increases with stellar mass (with moderate scatter) and bias also increases with stellar mass and redshift, consistent with previous studies. I find the satellite fraction increases towards low redshifts, from ∼ 5% at z ∼ 1.5, to ∼ 20% at z ∼ 0.6, also increasing for lower mass galaxies. I combine my results to derive the stellar mass to halo mass ratio for both satellites and centrals over a range of halo masses and find the peak corresponding to the halo mass with maximum star formation efficiency to be ∼ 2 × 10¹²M_⊙, finding no evidence for evolution. It has long been known that environment has a large effect on star formation in galaxies. There are several known plausible mechanisms to remove the cool gas needed for star formation, such as strangulation, harassment and ram-pressure stripping. It is unclear which process is dominant, and over what range of stellar mass. In this thesis, I find evidence for suppression of the cross-correlation function between massive galaxies and less massive star-forming galaxies, giving a measure of how less likely a galaxy is to be star-forming in the vicinity of a more massive galaxy. I develop a formalism for modelling environmental quenching mechanisms within the HOD formalism. I find that at z ∼ 2 environment is not a significant factor in determining quenching of star-forming galaxies, and that galaxies are quenched with similar probabilities in group environments as they are globally. However, by z ∼ 0.5 galaxies are much less likely to be star forming when in a group environment than when not. This increased probability of being quenched does not appear to have significant radial dependence within the halo, supportive of the quenching being caused by the halting of fresh inflows of pristine gas, as opposed to by tidal stripping. Furthermore, by separating the massive sample into passive and star-forming, I find that this effect is further enhanced when the central galaxy is passive, a manifestation of galactic conformity. Hydrodynamical cosmological simulations, with advances in computing power over the last decade, have recently made great advances in reproducing the galaxy population and understanding the underlying physical processes behind galaxy evolution. There is extensive research in the literature comparing predicted stellar mass functions from hydrodynamical simulations to observed stellar mass functions in data. In this thesis I extend these results, comparing clustering of galaxies in mock catalogues from the hydrodynamical cosmological simulation Horizon-AGN to clustering measurements from the VIDEO observations. Clustering and HOD modelling in the Horizon-AGN mock catalogue qualitatively recreates clustering measurements from the VIDEO data, but reflects the known excess stellar mass to halo mass ratio for low mass haloes in Horizon-AGN. This reinforces the need for stronger regulation of star formation in low mass haloes in the simulation. I extend my results into the high redshift regime by studying the large-scale structure of the bright high-redshift Lyman-break galaxy (LBG) population - gaining insight into the role of environment in galaxy formation physics in the early Universe. I measure the clustering of a sample of bright (−22.7 < M_UV < −21.125) LBGs at z ∼ 6 and use a HOD model to measure their typical halo masses. I find that the clustering amplitude and corresponding HOD fits sug- gests that these sources are highly biased (b ∼ 10) objects in the densest regions of the high-redshift Universe. Coupled with the observed rapid evolution of the number density of these objects, my results suggest that the shape of high lu- minosity end of the luminosity function is related to feedback processes or the onset of dust obscuration - as opposed to a scenario where these sources are pre- dominantly rare instances of the much more numerous M_UV ∼ −19 population of galaxies caught in a particularly vigorous period of star formation. Despite investigating several variations on the model, it was not possible to simultaneously fit both the number densities and clustering measurements. I interpret this as a signal that a refinement of the model halo bias relation at high redshifts or the incorporation of quasi-linear effects may be needed for future attempts at modelling the clustering and number counts. Finally, the difference in number density between the fields (UltraVISTA has a surface density ∼ 1.8 times greater than UDS) is shown to be consistent with the cosmic variance implied by the clustering measurements. Finally I discuss future data sets that will become available in the coming years, and future approaches to modelling large-scale structure. In summary I have shown that measuring the spatial distribution of galaxies on large-scales is a vital probe of galaxy evolution and an essential tool for understanding the connection between galaxies and their dark matter haloes over cosmic time.

Master of Science / Department of Grain Science and Industry / Charles R. Stark / A study was carried out to determine the effect of replacing fish meal with either soybean meal or poultry by-product meal on broiler performance and total feed cost per kg of gain. A second study evaluated the effect of storage time and trace minerals on the stability of vitamins stored at high temperature and relative humidity and their subsequent effects on broiler performance, bone strength and ash. A third study consisting of two experiments was conducted to determine the effects of particle size, diet, method of analysis (laboratory, ground and unground) and feed form (mash and pellet) on the crude protein predictability of the near infrared reflectance spectroscopy while using standard calibrations installed with the instrument. In study 1, three dietary treatments, 1) SBM-FM diet, 2) SBM diet and 3) SBM-PBM diet, were allocated to 36 pens using a completely randomized design with 12 replicates per treatment. Replacing FM with SBM and PBM in broiler diets improved growth performance and reduced total feed cost per kg of gain. In study 2, seven experimental treatments, 1) 0 d VP, 2) 30 d VTMP, 3) 30 d VP, 4) 60 d VTMP, 5) 60 d VP, 6) 90 d VTMP and 7) 90 d VP, were stored for 0, 30, 60 and 90 days, respectively in an environmentally controlled chamber at 29.4°C and 75%. Samples of treatments were analyzed, and loss of vitamin activity was calculated after storage. Treatments were added to broiler diets to determine the effect of loss of vitamin activity on broiler performance. Dietary treatments were set up as randomized complete block design in four batteries. Storing vitamins with trace minerals for 90 days increased loss of vitamin activity as compared to when stored as vitamin premix. Loss of vitamin activity did not significantly affect overall broiler performance, bone strength and ash. In study 3, Exp. 1 was a 3 × 3 × 4 factorial with corn particles size (400, 600 and 800 μm), method of analysis (laboratory, unground and ground) and diet (SD, SFD, SFB and SB). Diets were formulated to contain 20% crude protein. Subsamples were ground through a 0.5 mm sieve. Crude protein contents of ground and unground samples were analyzed using the Foss DS2500 NIRS (Model Foss DS2500 Monochromator, Foss NIRSystems, Laurel, MD) and compared to laboratory results from wet chemistry analysis. Interaction (P≤0.05) was observed between diet and method and particle size and method, but similar (P≥0.05) crude protein was observed for particle size. Diets and particle sizes were significantly different (P≤0.05) as unground samples but no differences (P≥0.05) were observed when ground and analyzed using the NIRS or wet chemistry. Exp. 2 was a 3 ×2 factorial with method of analysis (laboratory, unground and ground) and feed form (mash and pellet). Diets were formulated to contain 20% crude protein and manufactured with 600 μm corn particle size. Portions of diets were pelleted using a pellet mill and cooled. Ground and unground mash and pellets were analyzed as in Exp. 1. Interaction was found (P≤0.05) between feed form and method of analysis. Feed form and method of analysis significantly (P≤0.05) affected crude protein prediction from the NIRS. Crude protein content of ground mash and pellets were similar (P≥0.05) to that of laboratory results. Generally, analyzing finished feed samples in the unground form with the NIRS while using standard calibrations yielded less accurate predictions for crude protein, but samples in the ground form yielded similar (P≥0.05) results when analyzed with either the NIRS or wet chemistry.

This thesis focuses on developing a nondestructive strategy for measuring the quality of food using hyperspectral imaging. The specific focus is to develop a classification methodology for detecting bruised/unbruised areas in hyperspectral images of fruits such as strawberries through the classification of pixels containing the edible portion of the fruit. A multiband segmentation algorithm is formulated to generate a mask for extracting the edible pixels from each band in a hypercube. A key feature of the segmentation algorithm is that it makes no prior assumptions for selecting the bands involved in the segmentation. Consequently, different bands may be selected for different hypercubes to accommodate the intra-hypercube variations. Gaussian univariate classifiers are implemented to classify the bruised-unbruised pixels in each band and it is shown that many band classifiers yield 100% classification accuracies. Furthermore, it is shown that the bands that contain the most useful discriminatory information for classifying bruised-unbruised pixels can be identified from the classification results. The strategy developed in this study will facilitate the design of fruit sorting systems using NIR cameras with selected bands.

Doctor of Philosophy / Department of Anatomy and Physiology / Thomas J. Barstow / The primary aim of this dissertation was to describe the changes in microvascular hematocrit, as total[hemoglobin+myoglobin] (T[Hb+Mb] measured with near-infrared spectroscopy (NIRS), during post-occlusive reactive hyperemia (PORH). Mechanisms of reactive hyperemia within skeletal muscle were also explored. The investigation detailed in Chapter 2 of this dissertation found that the differing time courses of the kinetic responses of both oxy- and deoxy[Hb+Mb], are related to changes in T[Hb+Mb]. We also determined that adipose tissue thickness had no effect on a purely temporal analysis of NIRS data. In Chapter 3 we observed that brachial artery reactive hyperemia preceded changes in T[Hb+Mb] during reactive hyperemia. Assuming that myoglobin remained constant, we posited that changes in T[Hb+Mb] must reflect alterations in red blood cell concentration in the microvasculature, i.e., microvascular hematocrit. In Chapter 4 comparisons were made between brachial artery blood flow, cutaneous and skeletal muscle flux and T[Hb+Mb]. The conduit artery response was faster than the microvascular responses in all tissues. Within skeletal muscle, time to peak and the time constant for the on-kinetics were faster in T[Hb+Mb] compoared with intramuscular flux as measured with intramuscular laser-Doppler. We observed no differences in temporal responses between cutaneous and intramuscular measures and suggested that in a purely temporal analysis the cutaneous microvasculature could serve as an analog for the skeletal muscle microvasculature. Finally, in Chapter 5 we found that prostaglandin inhibition with ibuprofen altered the initial T[Hb+Mb] response during PORH without impacting cutaneous flux or brachial artery blood flow. Chapter 5 also discussed that the addition of a wrist cuff to our standard instrumentation prevented the accumulation of T[Hb+Mb] during the occlusion period.