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.

<p> In an effort to help alleviate low achievement and motivation in Turkish university preparatory English programs (Education First, 2015), an English teacher at Mihrimah Sultan University (pseudonym) in Istanbul, Turkey, conducted a study in which ten university English preparatory program students used a mobile language learning application, English Quickly (EQ pseudonym). The aim of the study was to ascertain whether or not the eight-week application usage period would help students to improve their English language skills as well as their motivation to practice English. The mobile application EQ was downloaded by the students in February 2017, and was used for eight weeks, terminating in April 2017. Students used the different functions of the application including watching videos, speaking, and learning new vocabulary. The conceptual framework used for the study consisted of an analysis of knowledge, motivation, and organizational influences based on the work by Clark and Estes (2008). Recommendations were generated and an evaluation plan was designed using the New World Kirkpatrick's Four Level Model (Kirkpatrick &amp; Kirkpatrick, 2016).</p><p>

abstract: In this work, atomic force microscopy (AFM) and time resolved confocal fluorescence microscopy are combined to create a microscopy technique which allows for nanometer resolution topographic and fluorescence imaging. This technique can be applied to any sample which can be immobilized on a surface and which can be observed by fluorescence microscopy. Biological problems include small molecular systems, such as membrane receptor clusters, where very high optical resolutions need to be achieved. In materials science, fluorescent nanoparticles or other optically active nanostructures can be investigated using this technique. In the past decades, multiple techniques have been developed that yield high resolution optical images. Multiple far-field techniques have overcome the diffraction limit and allow fluorescence imaging with resolutions of few tens of nanometers. On the other hand, near-field microscopy, that makes use of optically active structures much smaller than the diffraction limit can give resolutions around ten nanometers with the possibility to collect topographic information from flat samples. The technique presented in this work reaches resolutions in the nanometer range along with topographic information from the sample. DNA origami with fluorophores attached to it was used to show this high resolution. The fluorophores with 21 nm distance could be resolved and their position on the origami determined within 10 nm. Not only did this work reach a new record in optical resolution in near-field microscopy (5 nm resolution in air and in water), it also gave an insight into the physics that happens between a fluorescent molecule and a dielectric nanostructure, which the AFM tip is. The experiments with silicon tips made a detailed comparison with models possible on the single molecule level, highly resolved in space and time. On the other hand, using silicon nitride and quartz as tip materials showed that effects beyond the established models play a role when the molecule is directly under the AFM tip, where quenching of up to 5 times more efficient than predicted by the model was found. / Dissertation/Thesis / Ph.D. Physics 2012

Significant proportion of composite industry is currently produced using prepregs, cured in autoclave which is very expensive and time consuming process. Dry textile preforms in conjunction with liquid molding techniques can lead to significant reductions in material costs, manufacturing costs and cycle times. These dry preforms are typically 2D woven or braided fabrics which also required lay-up and have low interlaminar properties. Through thickness reinforcement provides solution for this problem as it gives better interlaminar properties as well as near net shape performing. Various 3D performing methods are discussed and reviewed in this research where 3D weaving comes out as ideal process to develop near net shape preforms with more efficiency and better material performance. This research highlights the advantages and limitations of conventional 3D weaving processes. A number of approaches for improving the flexibility of 3D weaving process have been presented including changing fiber architecture in different sections of the preform, tapering in the width and thickness directions and finally to change the fiber orientation. It is concluded that multi step and taper fabrics can be produced on conventional weaving by some modifications. Furthermore, a novel 3D weaving machine is designed and developed after reviewing various patents and weaving methods to overcome limitations of conventional weaving machine. Key criterions from limitations of conventional weaving processes are considered and modified such as multiple weft insertion, limited warp stuffer movement, linear take-up to develop 3D weaving machine. In order to achieve isotropic material, two textile technologies are combined to get final requirements. 3D weaving can provide us fibres in 0° and 90° direction with through thickness reinforcement, whereas braiding can satisfy the requirement of bias direction fibres. Near net shape preforms such as taper and multistep are produced and laminated. Preliminary testing is performed on these laminates to evaluate fibre architectures. Further work is required in terms of machine modification which can provide weave design flexibility to explore various multilayer weave architectures. Thorough testing is required to evaluate and define structure performance and effect of fibre damage during weaving process.

[pt] A caracterização do campo próximo em guias de onda ópticos torna-se indispensável quando se deseja confeccionar guias monomodo. Neste trabalho utilizou-se um sistema de medidas baseado na medida do campo próximo, para caracterizar guias de onda quanto ao seu conteúdo modal. Foram realizadas medidas do campo próximo de onda em GaAs/AlGaAs, com estruturas diferentes, para se verificar as suas características modais. Analisou-se, também, alguns parâmetros importantes nesta medida, como os alinhamentos e o ajuste do foco do sistema óptico. Baseado nos dados medidos, calculou-se o spot size dos guias nas direções horizontal e vertical, verificando-se a eficiência de acoplamento com fibras monomodo. Para se averiguar a precisão do sistema de medidas, uma fibra monomodo calibrada foi medida, verificando-se um erro de aproximadamente 1.5% nas medidas de spot size. / [en] Near field characterization of optical waveguides is extremely important in monomode waveguides production. This work has use a measurement system based on the near field measurement, for characterizing the modal contents of waveguides. In order to verify the modal characteristics of two GaAS/AlGaAs waveguides, with different structures, near fiels measurements were made. Important parameters, such as the alignment and the focal adjustment of the aoptical systems, were also analyzed. Using the results from the measurements, it was calculated the spot size of the waveguides in the horizontal and vertical directions, verifying the coupling efficiency with monomode fibers. A calibrated monomode fiber was measured to analyze the system precision. On using this measurement as a reference parameter a high precision was observed

The near-miss effect has been demonstrated to maintain gambling behavior by producing physiological changes or thoughts that an individual has "almost won" or was "close" to a winning outcome when, in fact, they lost. Participants were asked to rate each outcome presented on a 10-point Likert scale regarding how close they perceived an outcome was to a win on an automated slot machine created on a Visual Basic program. Data was analyzed for differences between similar outcomes presented with and without an auditory stimulus. Near-miss outcomes presented with an auditory stimulus were rated significantly higher than near-miss outcomes without an auditory stimulus on average across participants. Implications may reveal the effects auditory stimuli on modernized slot machines have on gambling behavior and options for treatment.

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.

Soybean (Glycine max [L.] Merr.) cultivars differ in their resistance to sudden death syndrome (SDS). The syndrome is caused by root colonization by Fusarium virguliforme (ex. F. solani f. sp. glycines). Breeding for improve SDS response has proven challenging, possible due to interactions among the 18 known loci for resistance. Four loci for resistance to SDS (cqRfs to cqRfs3) were found clustered within 20 cM of the rhg1 locus underlying resistance to soybean cyst nematode (SCN) on chromosome 18. Another locus on chromosome 20 (cqRfs5) was reported to interact with this cluster. The aims of this study were to compare the inheritance of resistance to SDS in a near isogenic line (NIL) population that was fixed for resistance to SCN but still segregated at 2 of the 4 loci (cqRfs1 and cqRfs) for resistance to SDS on chromosome 18; to examine the interaction with the locus on chromosome 20; and to identify candidate regions underlying quantitative trait loci (QTL). Used were a near isogenic line population derived from residual heterozygosity in an F5:7 recombinant inbred line EF60 1-40; SDS response data from 2 locations and years; four microsatellite markers and six thousand SNP markers. Polymorphic regions were found from 2,788 to 8,938 Kbp on chromosome 18 and 33,100 to 34,943 Kbp on chromosome 20. Both regions were significantly (0.005 < P > 0.0001) associated with resistance to SDS. A fine map was constructed that Mendelized the three loci. Substitution maps suggested the two loci on chromosome 18 were actually 3 loci (cqRfs, cqRfs1 and cqRfs19). Candidate genes for cqRfs19 were identified in a small region of the genome sequence of soybean. An epistatic interaction was inferred where the allele of loci on chromosome 18 determined the value of the locus on chromosome 20. It was concluded that SDS loci are both complex and interacting which may explain the slow progress in breeding for resistance to SDS.