UTSA Electronic Theses and Dissertations
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This collection contains electronic UTSA theses and dissertations (ETDs), primarily from 2005 to present. The collection is not comprehensive; search the UTSA Library Catalog for a complete list of UTSA theses and dissertations.
Since 2023, the UTSA Graduate School has required all theses and dissertations to be made publicly available in Runner Research Press. However, authors are able to request an embargo. Embargoed ETDs will not be downloadable until after their embargo expires.
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Item Detection and genetic analysis of emerging influenza field strains(2007) Daum, Luke ThomasThe emergence and evolution of new and virulent strains of influenza virus poses a continuing threat to mankind. The devastation caused by the great pandemic of 1918 and the recent (1997-2008) outbreak of H5N1 avian influenza isolated in humans has elevated concerns of yet another human pandemic. This dissertation is a compilation of original, peer-reviewed publications describing: (1) development of rapid and robust influenza detection strategies and (2) elucidation of the immunodominant influenza surface glycoprotein amino acid residues, i.e., hemagglutinin and neuraminidase that define antigenicity and impart antigenic drift significantly affecting annually the use of therapeutic influenza vaccines. Development and utilization of these influenza diagnostic assays should prove to be of considerable value for 'point of care' screening during a future pandemic influenza outbreak. Equally important, the elucidation of key amino acid mutations from human influenza A and B field strains presenting in the 2004 and 2006 influenza seasons described in this dissertation have contributed directly to formulation changes in the globally distributed trivalent vaccine employed for protection against circulating influenza strains.Item Optimization of a passive aircraft arrestor with a depth-varying crushable material using a smoothed particle hydrodynamics (SPH) model(2008) Barsotti, MatthewThis thesis explored the viability of a depth-varying passive arrestor system for civil aircraft applications. The current technology for such arrestors involves the use of large beds of crushable aerated concrete, which will safely decelerate aircraft that overrun the runway end. The aircraft rolls through the bed, dissipating energy as the tires crush the arrestor material. Currently, such arrestors utilize homogeneous foam materials. However, a given arrestor bed must function for all aircraft serviced on the runway of interest; such aircraft can differ in size, mass, tire diameter, landing gear configuration, etc. Consequently, the arrestor must function as a one-size-fits-all (OSFA) solution, despite its passive and static nature. The question explored in this thesis was, can a non-homogeneous, depth-varying material enhance the OSFA performance? The study developed LS-DYNA finite element (FEM) tire models for three aircraft: the B737, B747, and CRJ-200. These tires then interfaced with a numerical arrestor bed model, the properties of which were varied parametrically in an optimization study. The arrestor bed employed a Smoothed Particle Hydrodynamics (SPH) formulation, although the original research plan envisioned it as a FEM model. Several chapters outline the extensive comparison of the FEM and SPH methods, as applied to the arrestor model. Preliminary screening compared quadratic and linear depth-varying profiles for an arrestor material, using Radial Basis Function Network (RBF) metamodeling techniques in LS-OPT. The final optimization task targeted the linear profile, which appeared to offer the most promising performance improvement. The optimization showed that the linear depth-varying material offered several advantages over a homogeneous material, including inherent geometry matching with different tire sizes, reduced performance sensitivity for smaller tires, and overall improvement of the OSFA performance.Item Exercise as therapeutic angiogenesis: Post-myocardial infarction(2008) Wilson, Bryan ScottPost-myocardial infarction the left ventricle goes through a deleterious remodeling process that places a significant strain on the remaining viable myocardium. Like skeletal muscle the myocardium has demonstrated a remarkable plasticity response to both physiological and pathological stimuli. The purpose of this study was to demonstrate the temporal and spatial response of exercise induced therapeutic angiogeneis in a post-myocardial infarction rat model. Male Sprague-Dawley rats were randomly assigned to sham, sedentary myocardial infarction, and exercise myocardial infarction groups. Two weeks post-ligation the exercise myocardial infarction groups were trained on a rodent treadmill for 2 weeks, 4 weeks, and 8 weeks. Upon completing the respective training program the rats were sacrificed. To test the affect of the groups and time on therapeutic angiogenesis, transverse cross-sections of the myocardium were stained using indirect immunohistochemistry with an antibody against the endothelial cell marker CD-31. Using a point to count technique capillary density was measured in the left ventricle, the septum, and in the right ventricle. A significant main effect for the groups was found in all three regions of the myocardium (p < .05). However, no main effect for time or group and time interaction was found when measuring capillary density. These results suggest that exercise training post-myocardial infarction induces therapeutic angiogenesis in the viable myocardium.Item The effects of neuroticism on diurnal salivary cortisol and TNF-alpha in Mexican-Americans(2008) Rollins, Kathleen M.Studies have associated chronic stress with psychological and physiological pathology (Wadee et al., 2001). Certain individuals, with high levels of neuroticism, appear to be especially vulnerable to the effects of cumulative stress (Zobel et al., 2004). Neuroticism is associated with dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis (Oswald et al., 2006) and this dysregulation is associated with impaired immune system activity (Maes et al., 1998). The theory of Allostatic Load (McEwen, 1998) provides a framework to examine the relationships between neuroticism, HPA dysregulations, and immune activity in Mexican-Americans. Forty-nine Mexican-Americans between the ages of 18-38 completed self-report assessments of neuroticism factor/facets and subjective health, provided salivary cortisol for seven time points, and a serum sample for measurement of circulating TNF-alpha. Results of this study indicate that the factor of neuroticism and the facets of anxiety, depression, and self-consciousness are significant predictors of peak diurnal cortisol. General health also significantly predicted peak diurnal cortisol. However, neuroticism and self reported general health did not predict proinflammatory cytokine levels and although peak diurnal cortisol significantly predicted TNF-alpha level, a positive correlation was found between cortisol and TNF-alpha. Implications for the findings suggest that healthy Mexican-American individuals with higher levels of neuroticism may experience a dysregulation in HPA axis morning cortisol response and subjective health measured by self-report may be a predictor of morning peak cortisol response. The positive relationship between cortisol and TNF-alpha was significant but interpretation may require further investigation of the immune-neuro-endocrine interactions in Mexican-Americans.Item The significance of military aid on extreme violence in developing countries(2008) Padilla, AmandaMilitary aid is disbursed from super powers to developing countries that often have corrupt governments or regimes. This aid is used by repressive regimes to purchase manpower, training and arms with the intent of employing extreme violence. To assess military aids' influence on extreme violence, this thesis will examine the amount of military aid disbursed to governments/regimes after 1945 in cases where governments have eliminated their opponents or perceived enemies through extreme violence, including genocide. The regions of focus are Latin America and Africa; both regions have experienced extreme violence based on ethnicity, religion or political opposition. Previous literature has focused on the association between military aid and human rights abuses. However, there are gaps in previous literature regarding the significance of this association. This thesis will thoroughly analyze the significance of U.S. military aid on extreme violence in Chile (1973), Colombia (1952), Rwanda (1994), and Darfur (2004). The significance of U.S. military aid on extreme violence in developing countries is analyzed by establishing an association between the two variables, applying that association to the aforementioned developing countries, establishing repressive regime responsibility for acts of extreme violence, and examining U.S. military aid allocations to each respective country.Item Taking it with them: Elsewhere consciousness in the fiction of Edwidge Danticat, Paule Marshall, and Jamaica Kincaid(2008) Winterbottom, Linda A.This dissertation examines and develops the trope of "elsewhereness" in select fictional works by Edwidge Danticat, Paule Marshall, and Jamaica Kincaid. It presents an analysis that engages with and extends two earlier critical uses of the "elsewhereness" trope: those of Carole Boyce Davies and Michael Hanchard, both of whom theorize the term within discourses of Black Female Migratory Subjectivity and African Diasporas. Focusing mainly on female protagonists in the literature of Danticat, Marshall, and Kincaid, this analysis identifies a number of modes of "elsewhereness" that appear across these texts. The argument is that "elsewhereness" operates in these fictional narratives of post-colonial diasporic consciousness for female black Caribbean-American characters who strive for agency and an affirming sense of self while negotiating family and culture in the context of the painful histories of oppression wrought through the institutions of slavery and colonization. I further argue that by deploying constructs of "elsewhered" female Afro-Caribbean diasporic characters, Danticat, Marshall, and Kincaid produce a useful and collective study of the cultural and identiary problems and possibilities of Afro-Caribbean and Caribbean-American diasporic subjectivity. Thus this dissertation extends and develops the critical discourse on postcolonial narratives of Caribbean-American diasporic identity as a rich category within the broader spectrum of Comparative American Literatures.Item Reggeaton: Manifestacion artistica de los marginados(2008) Perez, Luz AdrianaReggaeton is the latest youth's manifestation in Caribbean music. Nearly two decades have passed since its conception and yet there are no conscientious studies about its origin and development. This dissertation has two objectives. The first one consists in building theoretical basis to help fill the gaps of disinformation that exist about reggaeton. The knowledge derived from the study will help to demonstrate that reggaeton is a genre and not a transient phenomenon. In order to support this argument, the investigation covered a meticulous examination of magazines, newspapers, television programs, music, assorted books and critical essays about Caribbean identity and culture. This research had facilitated the evaluation of the fertilization process, development, history, context, elements of style and character of reggaeton. The results confirmed that although reggaeton seems like a chaotic subcultural manifestation without order or foundation, it has a strong cultural, historical and ideological background. The lifestyle of the reggaetoneros is characterized by a strict organization, full of values, and orderly aesthetic codes. These criteria make the reggaeton a gender of Caribbean popular music and not an ephemeral occurrence.Item Inside the dragon's briefcase: China's emergent economy(2008) Heffner, LanetteThere is little doubt that China has undergone a remarkable transformation into a market economy. Yet 100 years ago, Political Sociologist, Max Weber, concluded that China's philosophical traditions, especially Confucianism, hindered the rise of market economic development. Weber argued that a market economy was not possible without a protestant ethic. This study re-examines Weber's thesis in light of modern China and concludes that economic reforms under Deng Xiaoping paved the way for a market economic transition despite the lack of a protestant ethic.Item Mutational analysis of tumor endothelial marker 8, an anthrax toxin receptor(2008) Karamsetty, RaghavendraAnthrax is caused by Bacillus anthracis, a rod-shaped, Gram-positive, aerobic, spore-forming soil bacterium. Two attributes that make it a potent pathogen: the capsule and anthrax toxin. The toxin is the major lethality factor. It comprises three secreted proteins-protective antigen (PA), edema factor (EF), and lethal factor (LF). Individually, the proteins have no toxicity, but PA+EF and PA+LF are highly toxic. EF is an adenylyl cyclase that harms cells by raising cAMP. LF is a Zn-dependent metalloprotease that cuts MAP kinase kinases, thus inactivating them. PA itself has no toxicity, but it is nonetheless crucial because it delivers EF and LF inside the cells by receptor-mediated endocytosis. PA uses two similar cell surface proteins as the receptors, tumor endothelial marker 8 (TEM8) and capillary morphogenesis gene 2 protein (CMG2), both single-pass integral membrane receptors. The ectopic portion of each receptor has a vWA domain and within this domain a metal ion dependent adhesion site (MIDAS). The vWA domain and the MIDAS motif are required for PA binding. TEM8 and CMG2 have multiple splice variants, some secreted and some membrane bound. Only the membrane bound forms support toxin entry. This work reports mutational analysis of TEM8, employing both random and site-directed mutagenesis. For this analysis, we used TEM8-var4, one of three membrane bound forms of the receptor. Var4 was amplified by nested PCR from human fetal brain cDNA and cloned into pIREShyg3, a mammalian expression vector. Over a hundred clones were sequenced to identify the wild-type, as well as the random mutations. All clones had more than one mutation, and no wild-type receptor was found. Thus, the wild-type var4 was constructed by recombining the wild-type segments of two mutants. The normal receptor and its mutant forms were expressed in a functionally receptor negative host cell line. The host cells expressing various receptors were then subjected to cytotoxicity assays with a modified form of anthrax toxin, PA+FP59, a potent cytocidal toxin. Receptor mutants derived by random mutagenesis had multiple mutations, many with combination of silent, conservative, and nonconservative changes. The effects of these mutations on receptor function varied dramatically; some had no effect and some others killed the receptor function. To segregate their effects, many mutations were individually made in the wild-type receptor by site-directed mutagenesis. The receptor functions were quantitatively assessed by comparing the IC50 values, defined as the toxin concentrations that resulted in 50% cell death. The IC50 for the wild-type receptor was 3-4 ng/mL of toxin. The individual mutations that resulted in the most drastic loss of receptor function were Q101L and R126W (IC50 values > 2000 ng/mL), both in the vWA domain. The mutations that did not kill receptor function but nonetheless resulted in considerable disruption were P37L, L69S, S143N, and G172C (IC50 values 30-80 ng/mL). An unexpected result was the markedly reduced receptor function when Q110L and C347R mutations were present simultaneously (IC50 ∼ 200 ng/mL), but little effect when they were present individually (IC50 ∼ 10 ng/mL). How Q110L mutation, which is in the vWA domain (outside the cell) and C347R mutation, which is in the cytoplasmic portion, together disrupt receptor function is unclear.Item Globalization and its influences upon the southern states of Mexico(2008) Alejandro, Michael VincentThe purpose of this study was to add to the extensive literature about economic globalization, but with a focus on a regional localized area of a state. Regional analysis of globalization influence on a region is necessary in order to adjust economic development according to local needs. This case study analyzed how globalization influenced the southern states of Mexico--Guerrero, Oaxaca, and Chiapas, considered the poorest region of Mexico by the World Bank. I hypothesized that economic globalization, which I define as the spread of liberal economics, helps the poor by increasing employment levels. However, this positive situation is diminished by increased vulnerability to fluctuations in the world market, thereby negatively influencing wealth generation. The analysis focused on the Gross Domestic Product (GDP) as the primary indicator for the generation of wealth in Mexico's southern states from 1993 to 2006. Specifically, I analyzed the manufacturing industry and divisions in which the southern states should have a comparative advantage---the wood and paper industries. The liberal reforms under review were those surrounding the trade liberalization policy of the North American Free Trade Agreement (NAFTA) and its influence on wealth development in Mexico's southern region. The conclusion of the study found that the southern state's GDP percentage declined in manufacturing divisions in which the southern states should have had a comparative advantage. Instead, the southern states are shifting to low-skill and low-wage jobs as the maquiladora industry shifts garment production to the south.Item Synchronous multidimensional optical code division multiple access(2008) Karovalia, SohelAn all-optical multi-access network is a collection of multiple nodes where the interconnection among various nodes is via single- or multi-mode fiber optics and for which they perform all their essential signal processing requirements such as switching, add-drop, multiplexing/demultiplexing and amplification in the optical domain. Optical CDMA networking is one possible technique that allows multiple users in local area networks to access the same fiber channel asynchronously with no delay or scheduling. Search for codes suitable to the optical domain is one of the important topics addressed in the literature on optical CDMA. Existing codes developed in the early 90's are limited to single class traffic or can support multiclass traffic but with restrictions on code lengths and weights. Also the number of generated codes is severely limited due to orthogonality issues. In this thesis, we pay particular attention to propose new codes that can support multiclass traffic with arbitrary code weights and lengths. We proposed an optical CDMA system based on polarization encoding. Finally we simulated a synchronous three dimensional OCDMA technique to attain the best performance of OCDMA.Item Efficient wavelength conversion using four wave mixing in semiconductor optical amplifier for intensity modulated differential phase shift keying signal(2008) Khambaty, YousufAll-Optical Wavelength Conversion (AOWC) in Dense Wavelength Division Multiplexing (DWDM) is believed to be the next generation networks that can meet the ever increasing demand for bandwidth of the end users. Wavelength division multiplexing (WDM) has become one of the most widely utilized multiplexing techniques for transmission of optical signals. As this technique promises a larger bandwidth, high data capacity and data rates it is considered as the most efficient. This thesis presents an efficient signal for wavelength translation in optical networks. We compared two signal i.e. non return to zero (NRZ) and intensity modulated differential phase shift keying (IM-DPSK). We performed our translation by using well known four wave mixing (FWM) technique. Our conversions try to translate the wavelengths in an efficient manner those results in very low blocking probability. We propose novel translation signal that outperform the signals reported in the literature even when converters are used. We performed simulation in which it is proven that IM-DPSK signal which has the BER of 10-11 are more immune to non linear effects during wavelength conversion. We also performed multi stage conversion to make our conversion more flexible within a same network. Further, we analyzed the optimum point of fiber length for different power levels which is affected by BER. Our proposed method are simple to implement and do not add to the cost. Thus, we conclude that wavelength conversion plays more significant role in affecting the blocking probability.Item Factors affecting the growth of Verbesina virginica(2008) Gagliardi, Jason W.Verbesina virginica (frost weed) is a tall, perennial, herbaceous plant that has been observed to occur in Bexar County, Texas primarily under established tree canopies such as Quercus fusiformis (scrub live oak) and Ulmus crassifolia (cedar elm). The distribution of Verbesina virginica, and possible factors affecting its distribution are not well reported. To better understand these factors, a combination of field studies, greenhouse experiments, and leaf level Li-Cor gas exchange analysis were utilized to examine species distribution, determine the species' nutrient requirements, and the plants response to various light levels, respectively. Over five transects, extending from a canopy into an adjacent open grassland, 283 total plants were counted. Of those, 98.9% (280 plants) were found inside the canopy dripline. Mean soil depth along the transects was highly variable and not significantly different from one location to another. However, a light gradient was found ranging from low light beneath the canopy (207 +/- 53 mumol CO2 · m-2 · sec-1) and increasing into the open grassland (2126 +/- 71 mumol CO2 · m-2 · sec -1). Overall, dry plant mass and leaves per plant increased with increased nutrient additions however, the plants did tolerate the native low nutrient Patrick soil. Gas exchange measurements for Verbesina virginica over 19 light levels ranging from 0 to 2000 mumol · m-2 · sec-1 found its maximum rate of photosynthesis (Amax) to be 12.68 +/- 1.40 mumol CO2 · m-2 · sec-1, while its mean dark respiration (Rd) was 0.75 mumol CO2 · m-2 · sec -1. The mean light saturation point (Lsat) for V. virginica was 287.74 mumol · m-2 · sec-1, and mean light compensation point (Lcp) was 16.2 mumol · m-2 · sec-1. These results fall within established ranges reported for understory species, and together with observed field distributions suggest that Verbesina virginica is a shade species.Item Theory, synthesis and characterization of nano-scale architectures for solid-state hydrogen storage(2008) Miller, Michael A.Traditional materials discovery and development techniques have not yet yielded the necessary breakthroughs needed for practical utilization of hydrogen storage. An integrated theoretical-experimental approach to the development of novel materials capable of hydrogen storage under the narrow thermodynamic regime suitable for automotive applications is undertaken. The viability of engineering two-part nano-architectures (heterostructures) to enhance the binding energy between molecular hydrogen and solid-state nanostructures, or to evince dissociation and uptake of hydrogen into the architecture, was explored. First, exceptional hydrogen uptake (7.5 wt.%) was validated in a metal organic framework compound, MOF-177, at low temperature (77 K), and a thermodynamic model for physisorption was established as a benchmark for all such structures. A chemisorptive pathway for enhanced hydrogen uptake (2.2 wt.%) at room temperature in heterostructures of metal-organic-frameworks (MOFs), via a mechanism now referred to as hydrogen spillover, was experimentally validated and further studied through computations. Ab initio computations at the level of Hartree-Fock (HF) and density functional theories (DFT) made it possible to calculate the thermochemical properties of hydrogen uptake in Pt-doped MOF heterostructures, which verified the thermodynamic plausibility of hydrogen spillover. Furthermore, the hydrogen spillover mechanism was successfully elicited from heterostructures consisting of metal-doped carbon materials, which yielded the highest uptake of hydrogen ever measured at room temperature (8.0 wt.%) for carbon-based material. The theoretical foundation was formed for a new way of considering how binding interactions between small molecules, such as dihydrogen, and an engineered surface may be influenced by coupling molecular vibrations with low-frequency surface plasmons in clusters of a metal compound. Finally, new MOF-based heterostructures in which a metal dopant is effectively caged within the pore structure were successfully synthesized using a new method of generating metal clusters. These unique structures were specifically engineered to take advantage of hydrogen spillover effects and to overcome the kinetic barriers associated with this mechanism. The results of this work have provided long-range benefits to the hydrogen storage field. More generally, this research has laid down the groundwork for important spin-off applications in catalysis, nanomaterials, spectroscopy, and plasmonics.Item Left ventricular mechanical properties post-myocardial infarction and the role of matrix metalloproteinase-9(2008) Pilia, MarcelloCoronary artery disease is the leading cause of death in the US. Myocardial infarction (MI) due to coronary artery disease is the leading cause of congestive heart failure. Understanding of the adaptation of left ventricle (LV) post MI is of paramount importance. Although significant progress has been made in understanding the pathophysiology of the LV remodeling process post MI, the underlying mechanisms of LV remodeling are not yet fully understood. Matrix Metalloproteinase-9 (MMP-9) is known to play an important role in the remodeling process of the heart. Decreased MMP-9 activity results in fewer ruptures of the myocardium in the affected area as well as less collagen formation. However, the underlying mechanisms are not clear. The objective of this study was to determine how the mechanical properties of the myocardium change with MMP-9 inhibition to determine the role of mechanical stress in the remodeling process. We hypothesized that after an MI, the myocardium of the LV remodels to compensate the damaged tissue, and therefore increase the LV stiffness, and that the LV myocardium of the MMP-9 null (knock out)mice will have lower stiffness than the C-57 mice. The overall objective of this study was to determine the stiffness of a healthy and of an infarcted heart to uncover the changes in the different models, and to determine how the stiffness of the left ventricle changes when comparing the myocardium of C-57 mice to the MMP-9 null mice. Four test groups were examined: healthy wild type C-57, C-57 with an induced MI, healthy MMP-9 null, and MMP-9 null with an induced MI. The mechanical properties of the LV were determined for each group 7 days after the MI. By comparing the differences between these groups it was possible to determine the role of both MI and MMP-9 in changes of myocardium mechanical properties. The results showed no significant change in stiffness for either type of mice before and after the MI. A big difference was seen in the change in end diastolic and end systolic stress (EDS & ESS) before and after the MI for both mice types (EDS PW P value = 0.0002; EDS SEP P value = 0.0013; ESS PW P value < 0.0001; ESS SEP P value = 0.0001). Once again, there was no difference in behavior between the C-57 and the MMP-9 null mice. In conclusion, we found a big increase in stress at end diastole and end systole. No differences were found between the C-57 and the MMP-9 mice, and the infarcted myocardium showed only a trend of increase in stiffness in the C-57 mice, but no significant result. More research needs to be done to determine the exact mechanism of interaction between the MMP-9 protein and the infarct remodeling process, and the search for a three-dimensional model to test more accurate living conditions of the heart.Item Gender, sex, individual income, and the choice to work in the twenty-first century(2008) Resetar, Dawn E.The belief that differences between men and women are biological, and the outcomes of this, has been widely studied. This research attempts to add to that body of knowledge through the use of the General Social Survey to examine the differential determinants of labor force participation and individual income for males and females in the twenty-first century. Demographic, human capital, household, income, and gender ideology variables provide a much a greater fit for explaining female labor force participation decisions than for men. Potential income and human capital variables significantly affect placement in the labor force for both males and females. Income and household variables only significantly classify females into the labor force categories. In the individual income analyses, human capital, work structure, and sex and gender variables come to the forefront of explaining variance. Across the male and female models, human capital yields similar returns to income while work structure and gender variables reveal underlying differences in individual income.Item An efficient static single assignment interpreter with translation(2008) Cramer, Adam LeeAlthough optimizing compilers often utilize Static Single Assignment Form (SSA) in their intermediate representations, most high-performance interpreters implement stack-oriented languages. While previous work had shown that interpreting SSA Form is feasible, the implementation reported previously did not support recursive function calls and was slower than commercial interpreters for the stack-oriented Java bytecode language. It remained an open question as to whether an SSA interpreter supporting recursive function calls could be made as efficient as a high-performance stack-oriented interpreter. This paper describes a high-performance interpreter for a variant of Static Single Assignment Form, known as Interpretable Static Single Assignment Form (ISSA). Through the use of well-engineered data structures and other optimizations, this interpreter is able to achieve performance comparable to that of well-engineered stack oriented Java Virtual Machine interpreters. This paper describes how to engineer an SSA interpreter to support for recursive function calls and indicates how standard SSA may be translated into ISSA for use in the interpreter, including the addition of ISSA-specific instructions and constructs. Finally, it reports on the performance of several implementation variants of computationally intensive benchmarks.Item The relationship between educational decisions and academic achievement: A focus on Mexican American students(2008) Fernandez, Mary RuthThis study explores the complexities of decisions made by educational teams and the relationship of those decisions to the achievement of Mexican American students considered at risk. To date no research has examined the outcomes of team decisions made on behalf of Mexican American students who have been considered for or provided with special education services. This study examines the relationship between the decisions made in response to educational progress in one or more of these areas of concern: reading, writing, speaking, listening, language, learning or behavior and the students' academic achievement. A sequential explanatory mixed method research design (Creswell, 2003) was selected because it allowed the researcher to achieve three goals. First, to explore how the decisions documented on the Educational Decision Inventory (EDI) associate with levels of achievement, second, to examine how the features of the team composition and process assist to explain student achievement and third to examine the factors that teams routinely use as they make decision about referrals and placement. Twenty-three student records were reviewed and eleven educators were interviewed. The results of the quantitative portion of the study suggest that language matches, educational placement and special services scattered typical to a much larger than typical association to grade point average, meeting TAKS reading standards and grade advancement. The results of the qualitative portion provided explanations of the challenges teams face as they make decisions regarding problems that Mexican American students have with learning in the classroom.Item Functional analysis of the anthrax toxin receptor CMG2 by alanine scanning mutagenesis(2008) Manam, SrikanthThe causative agent of anthrax is Bacillus anthracis, a large rod-shaped Gram-positive bacterium. The hallmarks of the bacterium's virulence are its capsule and anthrax toxin. The toxin is a collection of three secreted proteins: protective antigen (PA), edema factor (EF), and lethal factor (LF). EF and LF are the catalytic moieties that intoxicate cells. PA, itself nontoxic, delivers EF and LF inside cells, and it does this by receptor-mediated endocytosis. The toxin employs two mammalian cell surface proteins as the receptors: tumor endothelial marker 8 (TEM8; antxr1) capillary morphogenesis gene 2 protein (CMG2; antxr2). Both are closely related single-pass integral membrane proteins that have a von Willebrand Factor A (vWA) domain in their extracellular portions. Within the vWA domain, both receptors have a metal ion dependent adhesion site (MIDAS). The MIDAS motif and the vWA domain are indispensable for PA binding to both receptors. The receptors also have a membrane proximal segment that lies between the vWA domain and the transmembrane helix. While ample evidence has accumulated that the vWA domain is crucial for toxin binding and entry, so far the role of the membrane proximal segment has not been elucidated. Further, the mutational analysis of even the vWA domain has not been done to an appreciable degree, and such analysis of the membrane proximal region has not been done at all. Thus, identification of specific residues crucial for these proteins as anthrax toxin receptors remains to be done. To identify specific residues important for receptor function, we have carried out extensive mutational analysis of the vWA domain of CMG2-488, one of four splice variants of this protein. We also carried out limited mutational analysis of the membrane proximal portion of this receptor. Our overall strategy was to individually replace certain acidic, basic, polar, and aromatic residues with alanine, but we also targeted some hydrophobic residues for analysis. To assess the mutant receptors' capacity to support anthrax toxin entry, we expressed the plasmid-encoded receptors in JCR65, a functionally receptor negative hamster cell line. The results show that the receptor loses function when the MIDAS residues are replaced with alanine, consistent with previous findings. Of the acidic residues, D180A and E233A mutations rendered the receptor nonfunctional. Likewise, the basic residue mutations K101A, R111A, and R242A proved equally disruptive. Of the polar residues, only S87A mutation killed receptor function. Among the aromatic residues, F85A was the only mutation that proved detrimental to receptor function. A hydrophobic residue mutation, V115A, completely blocked intoxication of cells. The E233A, E289A, R242A mutations, which abolish receptor function, are in the membrane proximal segment of the receptor. None of these mutations has been described before. Indeed the three mutations constitute the first experimental evidence that the membrane proximal portion is important for toxin entry. A number of mutations did not abolish receptor function, but nonetheless proved significantly disruptive. Many of the mutations had little or no effect on receptor function. While much more analysis remains to be done, we think the current study represents a significant advance in understanding what particular residues in CMG2 are important for receptor function. Devising strategies to intercept anthrax toxin during late stages of infection is an imperative. Clearly a thorough understanding of how the toxin employs its receptors for entry and what particular receptor residues and subregions are crucial to support toxin entry would help devise such strategies.Item Teacher efficacy within a Core Knowledge learning community in a high stakes testing environment(2008) LeBaron, SandraThis study of 330 teachers in nine Core Knowledge elementary schools used the Teacher Sense of Efficacy Scale to analyze four types of efficacy: (1) overall teacher efficacy, (2) efficacy in student engagement, (3) efficacy in instructional strategies, and (4) efficacy in classroom management. In addition, the investigation employed two sets of teachers: those who have authored and implemented core knowledge units and faculty members who have only implemented the core knowledge components. The decision to explore the relationships between these core knowledge referents and aspects of teacher self-efficacy was based on prior research and the need to expand the work to a unique professional learning community that had not been previously studied. Bandura, (1986) states that self-efficacy is task specific. The specific task to be examined in this study is the writing of core units. Therefore, performing well in unit writing and showing mastery of this task should contribute to greater teacher efficacy. Even though there was only one statistically significant finding in this study i.e., (core writers had higher teacher efficacy in classroom management), in almost all of the comparisons the core writers had higher scores than the non-core writers in total efficacy, instructional strategies, student engagement, and classroom management.