Pulsed parabolic equation model of acoustic transmission (PPEMAT)

Underwater sound is very important in the field of oceanography where it is used for remote sensing in much the same way that radar is used in atmospheric studies. One way to mathematically model sound propagation in the ocean is by using the parabolic-equation method, a technique that allows range dependent environmental parameters. More importantly, this method can model sound transmission where the source emits either a pure tone or a short pulse of sound. Based on the parabolic approximation method and using the split-step Fourier algorithm, a computer model for underwater sound propagation was designed and implemented. This computer model differs from previous models in its use of the interactive mode, structured programming, modular design, and state-of-the-art graphics displays. In addition, the model maximizes the efficiency of computer time through synchronization of loosely coupled dual processors and the design of a restart capability. Since the model is designed for adaptability and for users with limited computer skills, it is anticipated that it will have many applications in the scientific community.

Characterization and modeling of multi-conductor transmission line using Finite-difference Time-Domain method

A two-dimensional, 2D, finite-difference time-domain (FDTD) method is used to analyze two different models of multi-conductor transmission lines (MTL). The first model is a two-conductor MTL and the second is a threeconductor MTL. Apart from the MTL's, a three-dimensional, 3D, FDTD method is used to analyze a three-patch microstrip parasitic array. While the MTL analysis is entirely in time-domain, the microstrip parasitic array is a study of scattering parameter Sn in the frequency-domain. The results clearly indicate that FDTD is an efficient and accurate tool to model and analyze multiconductor transmission line as well as microstrip antennas and arrays.

Syndemic Health Disparities and Resilience Processes Related to HIV Transmission Risk among African American/Black Men in South Florida

Rates of HIV infection continue to climb among minority populations and men who have sex with men (MSM), with African American/Black MSM being especially impacted. Numerous studies have found HIV transmission risk to be associated with many health and social disparities resulting from larger environmental and structural forces. Using anthropological and social environment-based theories of resilience that focus on individual agency and larger social and environmental structures, this dissertation employed a mixed methods design to investigate resilience processes among African American/Black MSM. Quantitative analyses compared African American/Black (N=108) and Caucasian/White (N=250) MSM who participated in a previously conducted randomized controlled trial (RCT) of sexual and substance use risk reduction interventions. At RCT study entry, using past 90 day recall periods, there were no differences in unprotected sex frequency, however African American/Black MSM reported higher frequencies of days high (P Qualitative data collected among a sub-sample of African American/Black MSM from the RCT (N=21) described the men’s experiences of living with multiple health and social disparities and the importance of RCT study assessments in facilitating reductions in risk behaviors. A cross-case analysis showed different resilience processes undertaken by men who experienced low socioeconomic status, little family support, and homophobia (N=16) compared to those who did not (N=5). The dissertation concludes that resilience processes to HIV transmission risk and related health and social disparities among African American/Black MSM varies and are dependent on specific social environmental factors, including social relationships, structural homophobia, and access to social, economic, and cultural capital. Men define for themselves what it means to be resilient within their social environment. These conclusions suggest that both individual and structural-level resilience-based HIV prevention interventions are needed.

Transmission, Legitimation, and Adaptation: A Study of Western Lamas in the Construction of ‘American Tibetan Buddhism’

This thesis presents a study of the role of western lamas within Tibetan Buddhism in America, arguing that the role of the lama is as an influential and central aspect in the development and transformation of the Tibetan Buddhist tradition in the west. This thesis argues how western lamas holding a position of authority act as a catalyst of change within their group and in the overall process of change and adaptation of the Tibetan Buddhist tradition in America, creating what may become ‘American Tibetan Buddhism.’ Three relevant areas regarding the role of the lama within the transforming tradition are identified: 1) the basis of authority of the lama, or how authority is obtained; 2) the use of such authority as a tool for change; and 3) transmission of the teachings and lineage.

Knowledge of HIV transmission risk behavior, and perceptions of risk among Haitian women living in Miami, Florida

This study was conducted to gain a more comprehensive understanding of HIV risk among Haitian women. The variables measured were: knowledge of HIV transmission, sexual risk behaviors, and perceptions of risk among Haitian women. The sociocultural aspect of the Haitian women's lives with regard to their risky behaviors was also examined. A total of 101 Haitian women (aged 25-53) who attended two comprehensive health clinics were interviewed. A combined questionnaire derived from both the ARM-Q and the RBA was used. In general, the women had good knowledge of the sexual transmission of HIV I AIDS and indicated that they were susceptible to HIV infection. However, knowledge and perceptions of risk were not translated into sexual risk-reduction behaviors with their partners. Multiplicity of partners and low incidence of condom use were the two major sexual risk factors isolated in this study. Results indicate Haitian women were more likely to use condoms if they possessed greater HIV knowledge and their sexual partners held more positive attitudes toward using condoms. Also, Haitian women may have failed to protect themselves because behavior changes could have involved threats to their social and economic survival, relationships and culturally sanctioned roles. This suggests the need to include male partners in HIV prevention interventions with Haitian women. Future research should focus on preventing high-risk behavior by improving knowledge, altering the male partners' attitudes toward condoms, and enhancing communication and negotiation skills. Nursing implications and recommendations for culturally sensitive and relevant AIDS prevention efforts are discussed.