Browsing by Subject "Growth"
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Item A study of the relationships found among age, grade, intelligence, school marks and traits of school children of the Plainview public schools for the school year 1928-1929(Texas Tech University, 1929-05) Ballengee, Eugene MarvinNot availableItem Amino acid nutrition for growth and health of neonatal pigs(2007-05) Lin, Carol; Kim, Sung W.; Wu, Guoyao; Galyean, Michael L.Raising healthy and fast-growing neonatal pigs improve overall productivity of swine production. High-lean type neonatal pigs have a large body size and a healthy body to resist disease but are fed with a low- protein diet. Providing required profiles of amino acids in a well-designed diet to neonatal pigs will allow more efficient swine production and decrease morbidity, mortality, feed cost, and nitrogen excretion. The main concern in sow-reared neonatal pigs is that less energy is provided by sows for piglet growth compared with artificially reared piglets. The nutrients from sow¡¦s colostrum and milk may not be able to provide maximum growth for neonatal pigs. Therefore, understanding the digestibility of dietary nutrients and the mechanism for regulating their utilization in neonatal pigs is crucial for improving the growth performance and health of the animals. This thesis covers: 1) determining the digestibility of nutrients in colostrum by neonatal pigs; and 2) the usefulness of N-carbamoylglutamate (NCG) as a dietary additive for neonatal pigs. In the first study, 12, 1-d-old male piglets were selected from three litters (four per litter) and housed individually in metabolism crates. All piglets were fed colostrum containing 0.25% chromium oxide as an external marker based on the following feeding program: 6 meals per day for an entire 3-d period, with 40 mL/meal for d 1 (240 mL/d), 55 mL/meal for d 2 (330 mL/d), and 70 mL/meal for d 3 (420 mL/d). Excreted feces and blood samples were collected for chemical analysis and immunoglobulin (Ig) G analysis, respectively. The apparent digestibility of protein, DM, and total amino acids in colostrum was calculated. Protein-bound and free amino acids in sow's colostrum were highly digestible (98.3 „b 0.1%) by neonatal pigs. In the second study, 27, 7-d old piglets were weaned from sows and assigned randomly to 3 dietary treatments; 1) the positive control dietary treatment (CON) containing 66.8% whey protein concentrate without N-carbamoylglutamate (NCG) and glutamic acid providing 26% CP; 2) additional NCG supplementation (NCGS) containing 56.8% whey protein concentrate with 0.08% NCG and 3.83% glutamic acid providing 25% CP; and 3) with additional glutamic acid (GLU) containing 56.8% whey protein concentrate with 3.91% glutamic acid providing 25% CP. Fresh liquid milk replacer was provided daily to piglets. Body weights of piglets were recorded and jugular venous blood samples were collected at d 7, 14, and 21 of age. Dietary of NCG supplementation might have effect on the growth performance of neonatal pigs by elevating concentrations of essential amino acids. Adding NCG and/or glutamic acid supplementation might reduce the usage of protein in the diet. However, further research is needed with regard to increasing the sample size in order to have a "true" negative control.Item Amtec power output optimization by investigating the grain size effect on its electrode materials(2006-12) Briggs, Justin B.; Lodhi, M. A. K.; Sill, Alan F.The Alkali Metal Thermal-to-Electric Converter (AMTEC) is perhaps one of the most desirable devices for directly converting heat into electrical energy, particularly for space applications. There has been a lot of research in the past for improving this device. Since AMTEC has been intended for deep space use its stability is expected to last a long time, 15 years or more. The two major components responsible for power output of AMTEC are the electrolyte and the electrode. In this work we focus research on the AMTEC electrodes, which could be improved further to reduce the power degradation as the time goes by in using the AMTEC. This study aims at improving the performance of the electrode by looking into the changes of the material properties inherent to it with respect to time. These parameters refer to the grain growth involved in the grain mobility model for electrode materials. If the grain size of the electrode material reaches a certain dimension, about 750 nm, the power output starts degrading fast. This is very important because this condition should not occur until after 15 years and corresponds to a power degradation percentage of 10 % for different electrode materials. The electrode materials studied in this work are Mo, TiN, RhW, and . It was found that adjusting four different paramters for these electrode materials gave a power degradation between 3 % to 22 %.Item Effects of dietary supplementation of lactobacillus-based probiotics on growth and gut environment of nursery pigs(2007-12) Rao, Samwel O.; Wilson, Kristopher R.; Kim, Sung W.; Dowd, Scot E.; Brashears, Mindy M.Antibiotic resistance as a result of continuous use has been a thorny issue in pig production. Focus has been directed therefore to use of probiotic supplementation as alternative. Probiotic supplementation has been suggested to benefit the host animal by stimulating appetite, improving intestinal microbial population balance, digestion and improvement of growth performance. Furthermore studies have also suggested a role for probiotics in stimulating the immune system. The objective of this study was to determine the effects of dietary supplementation of Lactobacillus-based probiotics on growth and gut health of newly weaned pigs. Twenty nursery pigs weaned at 21-d of age (6.68 ± 0.27 kg BW) were allotted to 2 treatment groups representing: (1) CON (probiotic-free; corn-soy diet) and (2) PB (test group fed a diet containing 0.2% lactobacillus based probiotics). Pigs were housed individually in metabolism crates and fed the diets for 15-d. At d-15, all pigs were euthanized to collect gut tissues and digesta. There were no differences (P > 0.05) in body weight, ADG, ADFI and FE between the treatments during 15-d period. The numbers of E. coli, Bifidobacteria, Lactobacillus spp., and total anaerobics in colon digesta were altered, although not statistically significant (P > 0.05). Major VFAs were acetate, propionate, isobutyrate, butyrate, isovalerate, and valerate. Acetate accounted for more than 60% of the total VFAs in both treatments while isobutyrate accounted for less that 0.5% of the total VFAs in both treatments. There was no difference (P > 0.05) observed in amount of VFAs in both treatments. There was also no difference (P > 0.05) in the apparent ileal digestibility of amino acids in the diets. Villi height was greater (P < 0.05) in the treatment group as compared to control group. A separate study was conducted to investigate the effects dietary supplementation with Lactobacillus-based probiotics elicits on the immune status of the nursery pig. Differential blood counts were determined on whole blood samples collected on d 13 of the study period. Total RNA was isolated from mesenteric lymph nodes. Gene expression was determined using a 12,000+ pig specific custom microarray, results of which were validated with quantitative PCR. For differential blood counts, there were no differences (P > 0.05) in lymphocyte, neutrophil and monocyte, WBC count, RBC count, hematocrit, and hemoglobin among treatment groups. Microarray results identified significant difference in the expression of 80 genes that were altered by lactobacillus-based probiotics supplementation. Of these genes, nine were comparatively induced (> 2.0 fold) and the rest were comparatively repressed (> 2.0 fold). Functional analyses of these genes identified 25 distinctly enriched functional categories. One of the primary functional categories identified showed significant repression of catalytic activity genes, which represented the majority of repressed transcripts (24.4%). Analyses indicated that lactobacillus based probiotics supplementation altered genes responsible for carbohydrate transport activity, cellular physiology process, defense to pathogens and immune response. In addition, genes related to proteolysis including PRSS2 and CTRB and genes involved in lipid metabolism including LIPC and PLA2G1B were also altered by lactobacillus based probiotic supplementation. Collectively, dietary supplementation of Lactobacillus-based probiotics at 0.2% may have beneficial effects by positively interacting with the intestinal mucosa and the microflora if the length of feeding was increased. The results from these studies indicate that dietary supplementation of Lactobacillus-based probiotics to nursery pig diets may be considered as a nutritional strategy for enhancing intestinal health and possibly positive immune response. Nonetheless, further studies are required to confirm and to elucidate the responsible mechanisms. In addition, the extent to which altered gene expression may affect the animal’s response to actual immune challenge conditions should be determined.Item Effects of Economic Structure on Regional Economic Performance(2014-06-04) Hong, Sa HeumSince the most recent recession, many local governments, which excessively paid attention to economic growth, have undergone tremendous difficulties caused by severe fluctuations. It shows that economic stability also has to be considered as another critical factor that constitutes regional economic performance. Thus, in this dissertation, I evaluate regional economic performance in terms of both growth and stability. In most previous studies, economic structure was found to be a factor that can affect both growth and stability at the same time. However, in terms of measuring economic structure, diversity and specialization have been commonly treated as the exact opposite, increasing in one means decreasing in the other. Some researchers recognized the existence of multiple specializations in an economy but this concept has never been operationalized and empirically tested. Therefore, I extend the body of previous research by formulating an indicator to empirically measure multiple specializations in regional economies and examine the effect of multiple specializations on both growth and stability in one framework. Moreover, the economic structural effects can be estimated differently depending on the macro-economic situations. However, previous studies rarely considered the effects of macro-economic situations when investigating the effect of economic structure. Thus, to overcome this limitation, I apply panel analysis for the same statistical models in the above using the panel data which were constructed with four different time periods based on different macro-economic situations. The empirical analysis in this study finds that multiple specializations might positively affect economic growth while diversity can hinder growth. Otherwise, this study finds that increasing the levels of both diversity and multiple specializations can help regions to promote economic stability. It suggests that a region with a multiply specialized economic structure is more likely to experience both growth and stability at the same time. Additionally, the results of panel analyses inform that the effects of economic structure on growth vary across different macroeconomic situations while these structural effects on stability are consistently estimated, regardless of macroeconomic situations. This suggests that the economic development strategy using economic structure may indicate the different effectiveness by their objectives (i.e., growth or stability) or the macro-economic situations (i.e., boom or bust).Item Entrepreneurial city : race, the environment, and growth in Austin, Texas, 1945-2011(2011-12) Busch, Andrew M., active 2011; Meikle, Jeffrey L., 1949-The primary concern of this dissertation is to give historical perspective to the idea of the creative city and the creative, or "new," "knowledge," or "postindustrial" economy that has produced this new form of urban space. Austin, Texas, one of the developed world's premiere creative cities, is used as a test case. Like many urban scholars, I focus on the manifestation of the city as a unique material expression of the capitalist order, and also on the city as a symbolic discourse that has helped to generate its material conditions, including consistent socioeconomic unevenness. In broad outline I am interested in the forces of capitalism that cause cities and regions to grow. I begin with a basic question asked by geographer Allen J. Scott: "How do competitive advantages (including capacities for creativity) of cities emerge, and how might they be enhanced by public action?" In the case of Austin, I argue that the city's competitive advantage was engendered by an ethos that valued free market competition and a focus on the dual economic engines of technology and leisure which city and university leaders identified during World War Two. Austin's economic ideology, which consciously eschewed fordist modes of production in favor of knowledge-based growth associated with the University of Texas, was poised to blossom when macroeconomic ruptures forced massive restructuring associated with globalization during and after the 1970s. The city's inherent advantage as a site of surplus knowledge production for Texas and the Southwest created a highly paid, educated labor market that business people and politicians viewed as the core element of a non-industrial city. Even before the 1970s Austin was well on its way to economic growth through technological accumulation and modes of production that took advantage of skilled labor markets. The creative city thus has a history that must be understood before policy is adopted based on non-transferable conditions of growth.Item Essays on financial and international economics(2009-05-15) Su, XiaojingItem Essays on pricing under uncertainty and heterogeneity in the finance-trade-growth nexus(2013-08) Yousefi, Seyed Reza; Whinston, Andrew B.My dissertation consists of empirical and theoretical essays on Microeconomic Theory and International Economics. The first chapter discusses the existence and characterization of a model that determines producer's optimal pricing and allocation rule as a preannounced markdown schedule. The mechanism focuses on pricing and operational implications of allotting scarce resources when customers are heterogeneous in their valuations and sensitivities towards availability of product. The proposed mechanism suggests that a carefully designed multistep markdown pricing could achieve optimal revenue when selling a single unit. However, to sell multiple units, monopolist should modify the implementation of markdown pricing by either hiding the number of available products or selling them via contingent contracts and upfront payments. In the second essay, we study the heterogeneity of finance and growth nexus across countries. Our paper contributes to the literature by investigating whether this impact differs across regions and types of economy. Using a rich dataset, cross-section and dynamic panel estimation results suggest that the beneficial effect of financial deepening on economic growth in fact displays measurable heterogeneity; it is generally smaller in oil exporting countries; in certain regions, such as the Middle East and North Africa (MENA); and in lower-income countries. Further analysis suggests that these differences might be driven by regulatory/supervisory characteristics and related to differing performance on financial access for a given level of depth. The third chapter analyzes contraction of exports in the aftermath of severe financial crises and tests for its heterogeneity across different industries and based on their credit conditions. It provides a theoretical framework to provide insight on why sectors are hit disproportionately during and in the aftermath of severe financial distresses, and confirms most of them with empirical estimations. The findings suggest that industries with greater reliance on outside financing and fewer shares of tangible assets experience greater contractions in export volumes in the years following a severe financial crisis.Item Evaluation of adrenal function, growth, carcass characteristics, blood metabolites, hematological and immune parameters in Angus, Brahman, Bonsmara X Angus and Bonsmara beef steers(Texas A&M University, 2006-10-30) Jacobs Hollenbeck, ReginaAdrenal function, blood metabolites, hematological parameters, growth, and carcass characteristics were compared in tropically-adapted (Brahman,) intermediate (Bonsmara and Bonsmara X Angus crossbred,) and temperate (Angus; n=10 each) beef steers. An adrenal gland challenge was conducted, entailing serial blood collection at 15-min intervals for a 12.5-h period, with administration of exogenous ACTH (0.1 IU/kg BW) 2.5-h into the experiment. Steers were maintained on Coastal bermudagrass pastures overseeded with ryegrass for five month; body weights and blood samples were obtained every 21 days. An anterior pituitary/adrenal gland challenge was conducted, entailing serial blood collection at 120, 90, 60 and 30 min prior to, and 10, 20, 30, 60 and 120 min following administration of exogenous CRH (0.1 ug/kg BW). Physical and physiological signs of heat stress were assessed, and blood samples were obtained for analysis. Exit velocity was measured. Carcass characteristics were determined post-slaughter. Statistical analysis was conducted using ANOVA for repeated measures, using least square means and Pearson??????s and Spearman??????s correlation analyses. Bonsmara and Bonsmara X Angus had lower basal cortisol (CS) than Angus and Brahman steers. Angus steers had greater adrenal responsiveness to ACTH, and responded faster to CRH than the other breedtypes. Bonsmara steers were slower in responding to CRH, and returning to basal CS following ACTH or CRH administration. Angus and Bonsmara X Angus grew faster during the finishing phase than Brahman or Bonsmara steers. Angus had higher quality grades than other breedtypes; rib-eye area and hot carcass weight were greater in Angus than Brahman steers, but similar among Angus, Bonsmara X Angus and Bonsmara steers. Angus and Brahman were less docile than Bonsmara and Bonsmara X Angus steers. Angus steers had higher respiration rates and serum concentrations of sodium, lower aldosterone during moderate heat exposure, and lesser serum concentrations of glucose, urea and cholesterol than tropically-influenced breedtypes. Angus had rectal and surface temperatures similar to those of Brahman, but greater than those of Bonsmara X Angus or Bonsmara steers. Intermediate breedtypes like the Bonsmara provide a compromise to producers, allowing them to address the demands of consumers while raising cattle better suited to survival in tropical climates.Item Evaluation of Performance Traits in Brahman Cattle: Blood Parameters, Calf Temperament, Residual Feed Intake, and Bull Reproductive Development(2010-10-12) Matheney, Kara J.The objectives of these studies were (1) evaluate the relationship between temperament, blood parameters, and performance in Brahman calves (n = 300); (2) evaluate the relationship between residual feed intake (RFI) and reproductive development in Brahman bulls (n = 41). Serum was collected at 24 h and d 21 to 24, and analyzed for total protein (TP) immunoglobulin G (IgG), and cortisol (CS). Calves were weighed at 24 h, weighed and evaluated for temperament using exit velocity (EV) at d 21 to 24, and at 28 d intervals thereafter. Beginning 28 d prior to weaning, and at 28 d intervals through 56 d post-weaning calves were evaluated for pen score (PS) used to calculate temperament score (TS = (EV+PS)/2). The average TS from 28 d prior to weaning and weaning was used to generate temperament groups; calves 1 SD below the mean being calm, those 1 SD above the mean being temperamental and all remaining classified as intermediate. Calf TS influenced WW (P = 0.04) and ADG from birth to weaning (P = 0.03). Serum TP at 24 h affected (P < 0.05) WW and ADG from birth to weaning. Serum IgG at 24 h affected (P = 0.03) WW. Brahman bulls (n = 41) were evaluated for RFI, insulin-like growth factor I (IGF-I), temperament, reproductive development, and ultrasound carcass traits. Serum was collected at d 0 and d 70 of the feeding trial and analyzed for IGF-I. Bulls were classified as efficient, intermediate, or inefficient (RFI classification method I) and as efficient or inefficient (RFI classification method II). Bulls were evaluated for temperament at weaning using TS. Temperament influenced (P < 0.05) IGF-I concentrations at d 0. Reproductive development was not affected (P > 0.05) by TS. Residual feed intake classification did not influence (P > 0.05) age at reproductive milestones. Ultrasound carcass traits were not affected by TS or RFI. Serum TP at 24 h was a viable indicator of future growth performance. Temperamental animals had lower growth rates in both studies. Reproductive development was not affected by RFI. BW at reproductive milestones was lower in temperamental bulls.Item The evolution of skeletal development in early tetrapods : anatomy and ontogeny of microsaurs (Lepospondyli)(2011-05) Olori, Jennifer Catherine; Bell, Christopher J., 1966-; Rowe, Timothy B.; Cannatella, David C.; Sprinkle, James T.; Anderson, Jason S.Because the ancestry of extant amphibians remains highly controversial, under traditional perspectives, amphibians and amniotes often are distinguished by differences in developmental mode rather than their evolutionary relationships. Resolution of relationships is important, however, because phylogeny affects interpretations of biology, including the evolution of development. To address those issues, I documented the growth and development of two extinct lepospondyls, Microbrachis pelikani and Hyloplesion longicostatum, and compared the patterns in those taxa to data from other tetrapods. I quantified allometry in the skeleton using both measurement-based and geometric morphometric analyses. I applied Ontogenetic Sequence Analysis (OSA), a size-independent method, to the reconstruction of ossification sequences based on fossils. I also documented skeletal morphogenesis and used Parsimov Analysis and Parsimov-based Genetic Inference of ossification sequence data to evaluate the three hypotheses of extant amphibian ancestry, the Lepospondyl (LH), Temnospondyl (TH), and Polyphyletic (PH) hypotheses. Skeletal growth in Microbrachis pelikani and Hyloplesion longicostatum is primarily isometric. Comparisons with data from other Paleozoic taxa suggest that isometry was the ancestral pattern of growth in tetrapods. All regression analyses had a linear fit indicating lack of an abrupt metamorphosis. Absence of metamorphosis is also supported by the possession of lateral lines in both taxa throughout ontogeny, and Microbrachis pelikani additionally retained gills. However, ossification of the skeleton was completed at small body size. The greatest resolution in ossification sequence reconstruction was achieved with OSA, but results from all reconstruction methods indicated advanced ossification of the pubis and delayed ossification of the scapula in the lepospondyls. In terms of total number of sequence shifts optimized across each hypothesis of amphibian relationships, the TH had the shortest tree length. However, the values for the three hypotheses did not differ significantly, demonstrating that none was supported strongly. Based on my synthesis of new developmental data, I propose that Microbrachis pelikani and Hyloplesion longicostatum expressed a mosaic pattern of skeletal development. That pattern included a gradual transition to an adult morphology, and a lack of an amphibian-like metamorphosis. A similar pattern is common to most early tetrapods and Eusthenopteron, supporting the hypothesis that metamorphosis is not ancestral for Tetrapoda.Item Management practices for sustainability of small, technology oriented businesses(2012-12) Quezada, Arturo; McCann, Robert Bruce, 1948-; Nichols, Steven Parks, 1950-The focal point for this research is a drilling automation small business. Questions regarding survival, growth, innovation, flexibility and professional management related to this technology business are seeded as the root for the research. Topics were selected based on the experience of the author as an attempt to provide answers to such questions. In a broader context, small businesses make an important contribution to the economy and job creation. Low survival rates raise questions about the factors that influence the success or failure of such businesses. Researches have attempted to identify such factors. However, there are limited theoretical models that were generated based on a small business setting. Many factors and their interactions among each other could determine the survival of a small business. However, there are techniques and philosophies that enhance the potential for success. Some of those techniques and philosophies proposed by authors researched are the Lean Startup methodology, analysis of roadblocks and speed bumps on the Product Development Process model, participative management, competencies alignment and outsourcing. Correlations between the small drilling automation business and research are made in order to generate the answers to the questions proposed initially. Ultimately, in regard to the company I work for, generation of intellectual property via outsourcing, deep knowledge of the potential market, financial flexibility obtained from capital and other resources by means of the relationships established helped the company to survive startup and grow. Founding expertise translated into good behavioral focus supported a sustained growth stage and competitiveness. There are applicable models and methodologies that serve to guide to faster innovation where associated risks are managed by having the multiple solutions available. The level of informality tolerated within the firm should be related to the level of performance, so for us there may be benefit to a more formal evaluation of the strategy, uncovering relationships and details not anticipated, that could lead to different decisions. Overcoming capital restraints to earn financial flexibility was particularly beneficial to our initial success. At current size and complexity level, it would be beneficial for our company to evaluate more formal tactical management.Item Mathematical models for plant competition and dispersal(Texas Tech University, 1997-05) Atkinson, David NormanIt is often dif icult for ecologists to apply experimental methods to answer their questions and to predict the consequences of population growth or variations in time and space. Mathematical modeling, which is based upon biologically reasonable assumptions, provides an alternative approach to some of these problems. Modeling allows ecologists to study how variables interact and to make predictions about what would happen if some of the variables changed. Moreover, models generated from first principles can be tested against observations in experimental systems; thus, tests for the hypothesis are possible.Item Mental muscularity: shaping implicit theories of intelligence via metaphor(2009-08) Anderson, Scott Victor; McGlone, Matthew S., 1966-Motivating students is a central challenge for many teachers, particularly in subjects students commonly perceive as “impenetrable,” such as statistics. One line of motivation research by C.S. Dweck (2006) has found that when students believe their intelligence is malleable (i.e., a growth mindset) and that learning is a function of effort, they show greater motivation, accept more learning challenges, and have improved performance outcomes relative to students who believe their intelligence is fixed (e.g., “I’m not a math person”). This dissertation extends research regarding implicit theories of intelligence by examining how metaphors of the growth mindset (e.g., the mind is a muscle) can be integrated as feedback into a computer program to encourage students to implicitly adopt the growth mindset relevant to statistics. The present study manipulated framing conditions with metaphorical, literal, and no feedback about the growth mindset. Results show that framing feedback implicitly in terms of the “mind as muscle” metaphor increased non-math major undergraduates’ willingness to accept learning challenges and their overall score on testing items relevant to statistical literacy, as compared to students who received literal feedback or no feedback about the growth mindset. Also, overall, gender differences were noted, with males accepting more learning challenges, passing on fewer difficult items, and having higher scores on testing items than females. Findings also indicate that participants’ psychological reactance and interest in fitness and muscularity (metaphor resonance) did not meaningfully change participants’ learning outcomes.Item Relationship breakups: are they all bad?(Texas Tech University, 2010-08) Buck, Erin; Hendrick, Susan S.; Hendrick, Clyde A.; Cook, Stephen W.; Winer, Jane L.This research focused on the link between attributions people make about relationship termination, coping strategies employed post-breakup and possible posttraumatic growth experienced as a result of a breakup. The research also studied the relations between past relationship breakups and current relationship satisfaction, level of respect for partner, and satisfaction with life. The measures used for this study included: a background inventory, the Relationship Breakup Attribution Measure (Tashiro & Frazier, 2003), the Problem Focused Style of Coping Scale (Heppner, Cook, Wright, & Johnson, 1995), the Emotional Approach Coping Scale (Stanton, Kirk, Cameron, & Danoff-Burg, 2000), the Posttraumatic Growth Inventory (Tedeschi & Calhoun, 1996), the Relationship Assessment Scale (S. Hendrick, 1988), the Respect Toward Partner Scale (S. Hendrick & Hendrick, 2006), and the Satisfaction with Life Scale (Diener, Emmons, Larsen, & Griffin, 1985). Correlations, regression analyses, and analysis of variance examined associations among the variables. Significant correlations were found among the variables for the total sample, for men and women separately, and for current dating status. Attributions and some coping strategies were predictive of posttraumatic growth for both men and women. For women, coping by emotional processing was related to life satisfaction, and growth from a prior relationship was related to current partner respect and relationship satisfaction. Respect and relationship satisfaction were positively correlated for both genders. Individuals in a romantic relationship had greater life satisfaction than individuals not in a relationship. Men’s satisfaction with life was significantly impacted by dating status, whereas women’s satisfaction with life was not. In general, women had higher levels of life satisfaction than men. Clinical implications of the results and future research possibilities are noted.Item Roles for zebrafish trpm7 in growth, skeletogenesis, kidney function and physiological ion homeostasis(2009-12) Elizondo, Michael Reuben; Parichy, David M.; Wallingford, John B.; Fischer, Janice A.; Paull, Tanya T.; Shankland, MartyDevelopment of the adult form requires coordinated growth and patterning of multiple traits in response to local gene activity as well as global endocrine and physiological effectors. In recent years the zebrafish has been utilized as a favorable animal model as a step towards dissecting and better understanding these postembryonic developmental processes. One of the more powerful methods utilized in zebrafish has been the identification of new gene functions through the use of mutant screens. The nutria mutant was recovered from one such screen to identify postembryonic defects in pigment pattern, growth and metamorphosis. These mutants exhibited a pigment cell defect, touch unresponsiveness and severe growth retardation. Here I will discuss my work towards dissecting the underlying developmental processes governing the phenotypic changes in nutria mutants. I characterize gross alterations in skeletal development in nutria mutants that lead to accelerated endochondral ossification but delayed intramembranous ossification. I show that the nutria phenotype results from mutations in trpm7, which encodes a transient receptor potential (TRP) family member that functions as both a cation channel and a kinase. I find trpm7 expression in the fish-specific, ion homeostasis-regulating gland known as the corpuscles of Stannius (CS), and in the mesonephric kidney. I show that mutants also develop kidney stones. Together these results suggest a role for trpm7 activity in regulation of physiological ion homeostasis. Next I confirm that role by identifying late-embryonic and early larval defects in the CS and the kidney, two organs that regulate physiological ion homeostasis. I demonstrate the early larval detection of kidney stones in trpm7 mutants and show that their appearance is presaged by decreased levels of total calcium and magnesium. Furthermore I establish a link between trpm7 function in the CS and stanniocalcin1 (stc1), a potent molecular regulator of calcium homeostasis. Finally, using transgenic overexpression and morpholino-oligonucleotide knockdown, I demonstrate that stc1 modulates calcium and magnesium levels in trpm7 mutant and wild-type backgrounds. Together these analyses establish postembryonic roles for trpm7 function in growth, skeletogenesis, kidney function, and physiological ion homeostasis.Item Soil amendments and seed treatments to improve germination of chile pepper(Texas Tech University, 1997-05) Attebury, Jim KellyFarmers in eastem New Mexico and in the southera High Plains of Texas have to contend with problems that growers in other areas do not (ViUalon, 1992). Due to the elevation, topography, and latitude of this agricultural area, early spring soil conditions provide a host of obstacles to crop establishment. This is particularly tme of chile peppers. Adverse environmental conditions, such as wide diuraal temperature differences, high winds, moisture variability, irrigation induced salinity, and soil cmsting, as well as pathogens and insects, or biological features, are also present. Planting is a critical time in chili production (Carter, 1994). Transplants offer one method of crop establishment, however, beyond a certain scale of production this becomes impractical. Cost of hybrid seed is also an economic factor since planting seed cost can range from $15-$700 per pound (Carter, 1995, personal communication ). The most serious problems faced by pepper producers in New Mexico and on the southera High Plains of west Texas is the difficulty of establishment of suitable stands when planted directly into field seedbeds. Direct-seeding into the soil is widely used but suitable stands are difficult to achieve. Peppers are planted very shallow, and seeds are susceptible to desiccation and chiUing injury, thereby intermpting the germination process. Root system development and anchorage of the plant is influenced by the method of plant establishment (Leskovar and Stoffella, 1995). This can have an impact on yield and quality of pepper pods. Attempted mitigating efforts have included seed pretreatments (soaking, hardening, priming, polymer treatments) to speed the germination process and soil treatments or conditioners (polymer treatments, phosphoms, anti-cmstant) to alter the soil conditions (Heydecker and Coolbear, 1977).Item Some Philosophical Origins of an Ecological Sensibility(2012-10-19) Carlson, CharlesThis dissertation is centered on problems within the history and philosophy of biology. The project identifies the philosophical roots of the current ecological movement and shows how a version of philosophical naturalism might be put to use within contemporary ethical issues in biology, and aid in the development of research programs. The approach is historically informed, but has application for current dilemmas. The traditions from which I primarily draw include classical American philosophy, particularly C.S. Peirce and John Dewey, as well as thinkers associated with the German Naturphilosophie movement, such as Goethe and Schopenhauer. There are deep, but often overlooked, resonances between these seemingly disparate traditions and contemporary biology that are located in the conflict between the developing organism and the ever-fluctuating environment. The dissertation makes the case for a shared description of nature among these traditions and proposes applications to burgeoning contemporary ecological interpretations of issues such as hybridization and epigenetics.Item Sustainable growth and affordable form : strategies for Austin’s future housing development(2016-05) Howard, Kevin Michael; Wegmann, Jake; Almy, DeanToday, Austin faces a housing affordability crisis driven by rapid population growth and increasing economic disparity. With a significant housing shortage, particularly in affordable units, Austin must build both in existing neighborhoods and in new communities on the periphery to balance its housing market. This report evaluates a series of recent housing projects in Austin in search of a sustainable model for residential development that balances equity, ecology, and economy. This analysis finds that no existing model provides affordable housing with good access to transit and urban amenities that can be marketed and reproduced at the scale necessary to balance Austin’s housing market. This report then analyzes the formal qualities that make housing development efficient and affordable for developers, taxpayers, and residents. An analysis of density and building construction technology explores the convoluted relationship of density and per-unit land and construction costs. Then, a case study evaluates and compares a series of street grid designs drawn from cases as varied as Tokyo and outskirts of Austin. Each grid is evaluated based on indicators of efficiency and walkability. This report identifies that there is likely an optimal density for maximizing per-unit affordability, which varies by land cost. This report also finds that, disregarding net density, automobile scaled infrastructure grids with large blocks and wide rights-of-way are found to perform well for development efficiency, but poorly for walkability. Alternatively, pedestrian scaled infrastructure grids with small blocks were found to be equally efficient provided that they were designed with narrow rights-of-ways for local streets. While highlighting lessons particular to Austin, this paper provides insights on housing affordability issues shared by many other cities, adding to the discussion of how to most sustainably deliver affordable housing in America’s growing cities.Item Sustaining growth through innovation(2011-08) Dailey, Zachary Edwin; Nichols, Steven Parks, 1950-; McCann, Robert B.This thesis seeks to identify a generalized strategy for businesses to follow in order to sustain long term growth. In particular, it focuses on innovation as the catalyst that drives the growth. To establish the foundation for building this strategy, it first looks at the need for businesses to sustain growth in order to remain healthy. After developing this link, existing research in business growth is examined. With this information, the strategy is then formulated. From here, two of the largest companies in the world based on market capitalization are evaluated over time against this strategy to show its ability to drive sustained growth and long term success.