On arterial contractility, energetic requirements of the cardiovascular system, and the formation of arterial sclerosis

The aorta has been viewed as a passive distribution manifold for blood whose elasticity allows it to store blood during cardiac ejection (systole), and release it during relaxation (diastole). This capacitance, or compliance, lowers peak cardiac work input and maintains peripheral sanguine irrigation throughout the cardiac cycle. The compliance of the human and canine circulatory systems have been described either as constant throughout the cycle (Toy et al. 1985) or as some inverse function of pressure (Li et al. 1990, Cappelo et al. 1995). This work shows that a compliance value that is higher during systole than diastole (equivalent to a direct function of pressure) leads to a reduction in the energetic input to the cardiovascular system (CV), even when accounting for the energy required to change compliance. This conclusion is obtained numerically, based on a 3-element lumped-parameter model of the CV, then demonstrated in a physical model built for the purpose. It is then shown, based on the numerical and physical models, on analytical considerations of elastic tubes, and on the analysis of arterial volume as a function of pressure measured in vivo (Armentano et al. 1995), that the mechanical effects of a presupposed arterial contraction are consistent with those of energetically beneficial changes in compliance during the cardiac cycle. Although the amount of energy potentially saved with rhythmically contracting arteries is small (mean 0.55% for the cases studied) the importance of the phenomenon lies in its possible relation to another function of the arterial smooth muscle (ASM): synthesis of wall matrix macromolecules. It is speculated that a reduction in the rate of collagen synthesis by the ASM is implicated in the formation of arteriosclerosis. ^

Schools and the formation of Black identity during the Civil Rights Movement: Change and resistance in Holly Springs, Mississippi, 1964--1974

Desegregation of social and public spaces was the most visible result of the Civil Rights Movement. After 1960, the integration of schools in Mississippi became a source of conflict. The social change of Civil Rights attacked the social order of White Resistance that supported the state superstructure. The public schools were a place for the discovery of identity for Blacks. The integrated on of the schools caused many Whites to leave rather than be integrated with Blacks. Desegregation of schools was also a slow process because the local and state government could not enforce the decisions of the US Courts, leading Blacks to realize their place in American society could only be secured through individual action. ^ This work explains the role of schooling during the integration of the Holly Springs Separate School System. The process of forging a new identity by local Blacks is examined against the forces of social change and resistance. I addition, this work examines the perils for the Blacks as they faced the uncertainty of change in the crucial Civil Rights years between 1964 and 1974. ^ This work analyzes how the Black community dealt with the problems triggered by the desegregation of the school system in Holly Springs, of a constructed social condition, a psychological state of being, the realities of racism and segregation, and the change and resistance between the individual and the collective. It is based on six months of field work investigation. Although the schools were a crucial aspect of community life for Blacks and Whites, Blacks did form their identity in them. Other institutions, such churches were more crucial. Second, the aspect of politeness and belief in law made the experience in Holly Springs unique to that place, and thus, warrants further study to determine its place within the Civil Rights Movement. Finally, while the political and economic control of Holly Springs remained with Whites, desegregation led to the resegregation of the public schools: as Whites left to private schools. ^

Smallpox vaccination, the establishment of vaccination boards, and state formation in Venezuela and Cuba in the nineteenth century

The Balmis expedition, sent to America by the Spanish monarch Charles IV in 1803, was a watershed in the history of Medicine as it made smallpox vaccination available for the first time, effectively prevented the disease from spreading, and saved thousands of lives. Immunization required complex administrative measures and political decisions including the creation of Vaccination Boards, all of which involved different sectors of Spanish American society. This dissertation argues that at the beginning of the nineteenth century the Spanish American colonial state had reached some level of maturity and cohesion that made it capable of executing this complex project in public health. The significance of this mobilization and the every-day experience in implementing this new public health measure is the center of this work. It is situated geographically in Venezuela and Cuba, entities which took different evolutionary paths in the nineteenth century. The organization and functioning of Vaccination Boards in these two areas are used to illustrate the state formation process, and sharp political differences in this critical period.

Three essays on self-employment transitions, organizational capital, and firm formation

This dissertation explores how economic, organizational, and personal factors affect self-employment transitions, occupational decisions, and firm formation activities of individuals at different positions in the skill distribution. The first essay of my dissertation studies how local unemployment rates differentially affect entry into self-employment by individuals at different places in the skill distribution. The empirical results show a positive correlation between local unemployment rates and entry into self-employment for low-ability workers, but not for high-ability workers. Including employer size to eliminate possible distortions showed that the positive association between unemployment and self-employment among low-ability workers is in fact driven by the small firm effect. Controlling for firm size yields a negative association between unemployment and self-employment among high-ability workers. Effects of organizational capital, human capital and physical capital, on the firm formation activities of people at distinct skill levels depend on the type of the industry which is chosen for the new firm. Two types of industries, capital-intensive and ability-intensive, are utilized to explore this hypothesis in the second essay. A capital-intensive industry requires more physical investment, and consequently more funds, whereas, an ability-intensive industry requires more human capital. It is shown that high human capital requirements are associated with higher earnings among the most able individuals, and therefore makes them more likely to found firms in an ability-intensive industry. Wealthy people are more likely to establish both capital-intensive and ability-intensive firms, even though the amount of funds necessary for two industry types differs. Moreover, entry into both industries is predicted to happen later in life due to the removal of entry barriers constituted by required investment spending using savings when old. Empirical mixed results are observed. The third essay investigates earning differentials between future entrepreneurs and their non-entrepreneurial colleagues. Results show that high-ability firm-owners in an ability-intensive industry were earning more than those that remained in wage-work, whereas, low-ability firm-owners in a capital-intensive industry were earning less than those remaining in paid-work.

Role of Pseudomonas aeruginosa mifSR Two-Component System in Antibiotic Resistance and Biofilm Formation

Pseudomonas aeruginosa is an opportunistic pathogen found in a wide variety of environments. It is one of the leading causes of morbidity and mortality in cystic fibrosis patients, and one of the main sources of nosocomial infections in the United States. One of the most prominent features of this pathogen is its wide resistance to antibiotics. P. aeruginosa employs a variety of mechanisms including efflux pumps and the expression of B-lactamases to overcome antibiotic treatment. Two chromosomally encoded lactamases, ampC and poxB, have been identified in P. aeruginosa. Sequence analyses have shown the presence of a two-component system (TCS) called MifSR (MifS-Sensor and MifR-Response Regulator), immediately upstream of the poxAB operon. It is hypothesized that the MifSR TCS is involved in B-lactam resistance via the regulation of poxB. Recently, the response regulator MifR has been reported to play a crucial role in biofilm formation, a major characteristic of chronic infections and increased antibiotic resistance. In this study, mifR and mifSR deletion mutants were constructed, and compared to the wild type parent strain PAOl for differences in growth and B-lactam sensitivity. Results obtained thus far indicate that mifR and mifSR are not essential for growth, and do not confer B-lactam resistance under the conditions tested. This study is significant because biofilm formation and antibiotic resistance are two hallmarks of P. aeruginosa infections, and finding a link between these two may lead to the development of improved treatment strategies.

Review of Research on Spiritual and Religious Formation in Higher Education

College students have diverse ways of expressing their spirituality. The purpose of this review is to examine and critique the research used to study college students’ spiritual and religious formation. Implications for faculty, student affairs professionals, and ministers doing research on spiritual formation in higher education are discussed.

Social institutions and identity formation : the interface between society and the individual

This thesis describes a study conducted to develop and refine a measure, the Social Institutions Rating (SIR), a group administered, self-report measure of institutional attributes and characteristics. This thesis reports data on the psychometric properties of the SIR. Exploratory analyses are reported investigating the empirical effects of social institutions on identity formation within two ethnic/cultural groups, Euroamericans and Hispanics. Based on previous studies with ethnic minorities, a directional hypothesis was tested. The hypothesis that subjects in the Euroamerican sample have a higher identity status than the Hispanic sample for three identity domains (personal, interpersonal, and world view) was not confirmed. The hypothesis that subjects in the Euroamerican sample would score higher on identity satisfaction and lower on identity dissatisfaction than the Hispanic sample for nine content areas of identity was partially supported but in the opposite direction. Hispanics reported higher satisfaction on sense of self and religious issues than Euroamericans.

Effect of gamma-irradiation on total organic carbon and trihalomethane formation potential

This research was conducted to study the use of radiation in water treatment as an alternative to chlorination which has caused health concerns due to the formation of harmful disinfection by-products. Groundwater solutions from the Biscayne aquifer were radiated with Cobalt-60 gamma radiation and studied for changes in dissolved organic carbon (DOC), UV absorbance at 254 nm (UV254), fluorescence and trihalomethane formation potential (THMFP). Molecular fractionations were conducted by ultrafiltration. Effect of the combination of radiation/peroxide was studied for DOC and UV254. Radiation showed significant removal in DOC and THMFP. Similar results were seen in the fluorescence and UV absorbance experiments. Radiation/peroxide did not improve the DOC removal. Radiation of the groundwater samples broke the larger molecular weight fractions in to smaller fractions.