Browsing by Subject "persistence"
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Item Examining the Relationship Between Minority Status Stress, the Social Change Model of Leadership Development, and Persistence of Black Students at Predominantly White Institutions(2012-10-19) Brown, Lesley-AnnMinority status stress, which is the stress Black college students experience at predominantly White institutions (PWIs) as a result of their racial minority status, has been found to negatively impact their persistence in college. Two manuscripts were developed for this dissertation. The first is a critical literature review which establishes the relationship of minority status stress, persistence, and leadership values within psychological and higher educational scholarship of Black students at PWIs. The paper seeks to clarify the connection between the aforementioned variables as it relates to the Black student experience at PWIs. As minority status stress causes a threat to Black student persistence, leadership conceptualized using the values or the Cs of the Social Change Model of Leadership Development (SCM) were introduced as coping methods Black students have used to increase their persistence and minimize the negative effects of minority status stress. The second article is a quantitative study examining the relationship of minority status stress and persistence employing the Cs of the SCM as mediators in a sample of 340 Black college students. Results indicated that none of the Cs of the SCM fully mediated the relationship between minority status stress and persistence when employed as composite scores. However, when the six individual factors of minority status stress (environmental stressors, race-related stressors, racial-identity stressors, intrapersonal and interpersonal stressors, achievement-related stressors, and minority status stressors) and the 5 factors of persistence (academic and intellectual development, faculty concerns for student development and teaching, interactions with faculty, institutional and goal commitments, and peer group interactions) were employed in a series of multiple mediation analyses with the Cs of the SCM as mediators, there were several instances of full mediation by the Consciousness of Self, Citizenship, and Change values. The findings emphasized the importance of these three values in conceptualizing Black student leadership at PWIs and in understanding the role of leadership in Black student persistence in lieu of minority status stress. Suggestions for future research, implications, and recommendations for student affairs practitioners, other student services providers, faculty, and staff are discussed.Item Identification and characterization of cell-adapted mutations in West Nile Virus and replicons(2007-12-19) Shannan Lee Rossi; Peter W. Mason; Scott Weaver; Robert Tesh; Ilya Frolov; Charles RiceFlavivirus persistence in cell culture is achieved by altering the interaction between the viral genome and the host cell. To identify some of the factors that contribute to a persistent West Nile virus (WNV) infection, WNV subgenomic replicon (WNR) genomes were modified to contain neomycin phosphotransferase (antibiotic-resistance) gene and cells that persistently harbored this WNR were selected for using G418. There were many changes to the genomes harvested from WNR-bearing cell cultures compared to the parental genome, perhaps the most striking was the prevalence of NS2A mutations. WNR and WNV genomes harboring these mutations replicated more poorly than wt WNR or WNV genomes in vitro. These NS2A mutant genomes, as well as a genome with a large deletion in the 3’ UTR, were highly attenuated Swiss-Webster outbred mice. Low levels of IFN were produced from cells infected with NS2A or 3’ UTR deletion WNR genomes compared to wt WNR genomes. Since the WNR and WNV cannot efficiently replicate, little stress is placed on the cell during replication, resulting in minimal engagement of the cell’s stress and apoptotic responses and a noncytopathic infection. As a result, little cytopathic effect and apoptotic death were observed in cells infected with NS2A or 3’ UTR deletion WNR mutants compared to cells infected with wt WNR genomes. This lack of death may have been attributed to low levels of CHOP, a pro-apoptotic protein that is induced during endoplasmic reticulum stress. Taken together, these data support the hypothesis that WNR and WNV genomes that replicate poorly do not efficiently produce signs of their replication that can be recognized by the cell and place little stress upon the cell, resulting in an attenuated noncytopathic, persistent infection.Item Utilization of the persistent nature of Brucella in the development of live vaccines(Texas A&M University, 2006-10-30) Hong, Priscilla ChristineThe roles of genes responsible for the survival and persistence of Brucella in the host and the relationship between these genes and the disease were investigated via signature-tagged transposon mutagenesis. As much as 8% of the Brucella genome is important for survival of this organism in the host. This is an unusually high number and may help to explain the chronic or persistent nature of Brucella infections. Mutants attenuated in the mouse model were divided into two groups. The early mutants failed to establish infection or colonize the host. The late mutants colonized the host but failed to maintain infection. The vaccine potential of two mutants (virB10 and gcvH) that were unable to sustain infection was compared to that of a vaccine strain, S19. Survival of strain S19 in vivo was up to 12 weeks while virB10 and gcvH mutants were cleared from spleen at 8, and 24 weeks post-inoculation, respectively. Mice were vaccinated with individual mutants and then challenged with virulent S2308 at 8, 16, and 24 weeks postvaccination. As a result, protective immunity correlated with persistence of the mutant strain [gcvH>virB10]. These results suggest that survival is one of several factors that may influence protective immunity making it difficult to compare strains. For example, examination of host immune response revealed a similar pattern of host immune function (TH1 over TH2) in all mice except those vaccinated with virB10 mutant. Since gcvH mutant provided the best immunity, experiments were designed to explore its contribution of persistence to protection. In an effort to reduce non-specific activation induced by prolonged survival of gcvH mutant, protection was monitored after different periods of vaccination exposure followed with doxycycline treatment. In these studies, persistence of gcvH mutant enhanced protection against challenge. Overall, defined mutations in genes affecting survival may render mutants as vaccine candidates capable of stimulating protective immunity equal to or better than fortuitously isolated attenuated strains. Future studies should focus on characterization of these and other genes responsible for the persistence of Brucella to improve the safety and efficacy of live vaccines.Item ?When You Want Something So Bad, You Can Always Do It:? Mexican Women Journeying from the GED to Community College Graduate in a Southwestern State(2014-07-09) Russo, Renata FerreiraThe Hispanic population is the fastest growing population in the United States. Mexicans, who represent the largest Hispanic ethnicity, are also the most undereducated. Mexican women struggle between their roles as housewives and their desire to complete a higher education degree in order to improve their lives. The purpose of this study was to examine the internal (personal) and external (institutional) factors that influence female Mexican GED graduates? persistence in completing associate?s degrees at a community college in southeast Texas. A basic interpretive approach was employed to frame this study and to collect and analyze data. The sample consisted of twelve female Mexican GED graduates in their second year of postsecondary education. Additionally, two secondary sources were used to collect data for the study: interviews with two academic counselors from the institution, and institutional data showing student demographics. A thematic approach was utilized to analyze data from the audio-recorded and transcribed interviews. The findings revealed that the institution played a significant role in facilitating the female Mexican GED graduates? completion of their degrees. Supportive teachers, services such as counseling, and financial aid all had a strong impact on the participants? persistence. The findings also showed that pregnancies at an early age caused major setbacks in connection with their educational pursuits. Yet the participants also pointed out the support they received from parents and other family members. While many of the participants? parents did not themselves have high school diplomas, they had made education a priority for their daughters. A fourth finding suggests that the individual resilience of the participants played a significant role in their educational perseverance. The women in this study showed remarkable resilience in response to the many barriers they faced, overcoming these in order to remain in school through degree completion. The overall findings show that Mexican women who immigrate to the United States face significant obstacles with respect to earning their two-year college degrees. However, some of these women managed to complete their education by relying on supportive teachers, services, and family members. Most importantly, those who reached their educational goals showed great personal resilience and motivation to persist in order to provide a better life for themselves and their children.