Household Disruption and Sexual Victimization Among Young South Africans.

This dissertation comprises two empirical articles investigating the influences of household-level disruption and sexual victimization on the sexual and reproductive behavior of young South Africans, and a third identifying methodological limitations of research on sexual victimization. In particular, the empirical articles examine whether: 1) Household-level disruptions are associated with increases in young people’s risky sexual behavior and whether disruptions accumulate to produce greater influences; and whether 2) Sexual victimization increases the likelihood of adolescent pregnancy. Each uses a multi-disciplinary perspective to identify and address important gaps in the literature and the analysis on sexual victimization corrects significant methodological shortcomings of previous research. Taken together, the articles underscore the need for more and better research on the influences of trauma and disruption on the lives of young people and provide some direction for these efforts. Results indicate that young people experiencing a single household-level disruption or multiple disruptions do not demonstrate increased sexual activity or involvement with older partners, nor are they less likely to use condoms. I discuss data limitations that may explain these findings and suggest improvements to future research. Conversely, experiencing some forms of sexual victimization is associated with an increased hazard of adolescent pregnancy. Unexpectedly, however, respondents who were the most severely sexually victimize were no more likely to become pregnant during adolescence than respondents who were not sexually victimized. These results suggest that existing theories may need modification to account for a wider range of individual behaviors. The third article provides a substantive methodological critique of existing research on sexual victimization and offers examples of how limitations and inconsistencies in definitions, methods, and measures may affect the research findings and impede the accumulation of knowledge. In particular, it identifies methodological shortcomings that undermine the validity of previous findings, including the lack of attention to racial/ethnic diversity and other sample selectivity, problematic assumptions underlying survey questionnaires, and issues related to temporal ordering and confounding variables. Furthermore, it describes some methodological and analytical decisions made by scholars of this research that make it difficult to compare findings across studies and determine the state of knowledge on the topic.Ph.D.SociologyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/60663/1/susanml_1.pd

A comparison of the effect of oral versus written lesson closure on the achievement of seventh and eighth grade students in social studies

This was an experimental study which compared two different instructional methods, oral lesson closure versus written lesson closure, on the achievement of 156 junior high school students in social studies. This study was composed of two duplicate experiments. Experiment I was conducted with 71 seventh grade social studies students at School A, and Experiment II was conducted with 85 eighth grade history students at School B. A pretest posttest control group design was used for both experiments. The control group was given oral closure and the experimental group was given written closure. Posttest scores were compared using analysis of covariance at the .05 confidence level. The treatment was a lesson closure activity in which students summarized major points of the lesson orally in pairs or by writing a paragraph. Closure occurred in a ten minute time period at the conclusion of all instruction for the lesson objective. Each treatment was given to two seventh grade classes and to two eighth grade classes for six weeks. Although this study did not strongly identify either oral lesson closure or written lesson closure as more effective than the other, it did show both instructional methods to be similarly effective in promoting mastery of social studies facts. Lesson closure is an important strategy for teachers to use to help students learn. This study raises an interesting question regarding age and school performance. The findings from both experiments indicated that younger students performed significantly better in academic achievement than older students in the same grade. Could younger students summarize more skillfully or did they comprehend lesson content more readily? Further research is suggested regarding the issue of adolescent age and academic performance

A Real-Time Capable Software-Defined Receiver Using GPU for Adaptive Anti-Jam GPS Sensors

Due to their weak received signal power, Global Positioning System (GPS) signals are vulnerable to radio frequency interference. Adaptive beam and null steering of the gain pattern of a GPS antenna array can significantly increase the resistance of GPS sensors to signal interference and jamming. Since adaptive array processing requires intensive computational power, beamsteering GPS receivers were usually implemented using hardware such as field-programmable gate arrays (FPGAs). However, a software implementation using general-purpose processors is much more desirable because of its flexibility and cost effectiveness. This paper presents a GPS software-defined radio (SDR) with adaptive beamsteering capability for anti-jam applications. The GPS SDR design is based on an optimized desktop parallel processing architecture using a quad-core Central Processing Unit (CPU) coupled with a new generation Graphics Processing Unit (GPU) having massively parallel processors. This GPS SDR demonstrates sufficient computational capability to support a four-element antenna array and future GPS L5 signal processing in real time. After providing the details of our design and optimization schemes for future GPU-based GPS SDR developments, the jamming resistance of our GPS SDR under synthetic wideband jamming is presented. Since the GPS SDR uses commercial-off-the-shelf hardware and processors, it can be easily adopted in civil GPS applications requiring anti-jam capabilities

A Detailed Investigation into Low-Level Feature Detection in Spectrogram Images

Being the first stage of analysis within an image, low-level feature detection is a crucial step in the image analysis process and, as such, deserves suitable attention. This paper presents a systematic investigation into low-level feature detection in spectrogram images. The result of which is the identification of frequency tracks. Analysis of the literature identifies different strategies for accomplishing low-level feature detection. Nevertheless, the advantages and disadvantages of each are not explicitly investigated. Three model-based detection strategies are outlined, each extracting an increasing amount of information from the spectrogram, and, through ROC analysis, it is shown that at increasing levels of extraction the detection rates increase. Nevertheless, further investigation suggests that model-based detection has a limitation—it is not computationally feasible to fully evaluate the model of even a simple sinusoidal track. Therefore, alternative approaches, such as dimensionality reduction, are investigated to reduce the complex search space. It is shown that, if carefully selected, these techniques can approach the detection rates of model-based strategies that perform the same level of information extraction. The implementations used to derive the results presented within this paper are available online from http://stdetect.googlecode.com

Optical Magnetometry

Some of the most sensitive methods of measuring magnetic fields utilize interactions of resonant light with atomic vapor. Recent developments in this vibrant field are improving magnetometers in many traditional areas such as measurement of geomagnetic anomalies and magnetic fields in space, and are opening the door to new ones, including, dynamical measurements of bio-magnetic fields, detection of nuclear magnetic resonance (NMR), magnetic-resonance imaging (MRI), inertial-rotation sensing, magnetic microscopy with cold atoms, and tests of fundamental symmetries of Nature.Comment: 11 pages; 4 figures; submitted to Nature Physic

Conceptualizing pathways linking women's empowerment and prematurity in developing countries.

BackgroundGlobally, prematurity is the leading cause of death in children under the age of 5. Many efforts have focused on clinical approaches to improve the survival of premature babies. There is a need, however, to explore psychosocial, sociocultural, economic, and other factors as potential mechanisms to reduce the burden of prematurity. Women's empowerment may be a catalyst for moving the needle in this direction. The goal of this paper is to examine links between women's empowerment and prematurity in developing settings. We propose a conceptual model that shows pathways by which women's empowerment can affect prematurity and review and summarize the literature supporting the relationships we posit. We also suggest future directions for research on women's empowerment and prematurity.MethodsThe key words we used for empowerment in the search were "empowerment," "women's status," "autonomy," and "decision-making," and for prematurity we used "preterm," "premature," and "prematurity." We did not use date, language, and regional restrictions. The search was done in PubMed, Population Information Online (POPLINE), and Web of Science. We selected intervening factors-factors that could potentially mediate the relationship between empowerment and prematurity-based on reviews of the risk factors and interventions to address prematurity and the determinants of those factors.ResultsThere is limited evidence supporting a direct link between women's empowerment and prematurity. However, there is evidence linking several dimensions of empowerment to factors known to be associated with prematurity and outcomes for premature babies. Our review of the literature shows that women's empowerment may reduce prematurity by (1) preventing early marriage and promoting family planning, which will delay age at first pregnancy and increase interpregnancy intervals; (2) improving women's nutritional status; (3) reducing domestic violence and other stressors to improve psychological health; and (4) improving access to and receipt of recommended health services during pregnancy and delivery to help prevent prematurity and improve survival of premature babies.ConclusionsWomen's empowerment is an important distal factor that affects prematurity through several intervening factors. Improving women's empowerment will help prevent prematurity and improve survival of preterm babies. Research to empirically show the links between women's empowerment and prematurity is however needed

Reproductive Health and Bodily Integrity in Tanzania

Several policy initiatives support the empowerment of women to improve their reproductive health. Little is known, however, about the inverse effect that reproductive health might have on women’s empowerment. Women are pressured to conform to their reproductive role, and an inability to do so might affect their empowerment, including control over their own body. This study uses a panel dataset of 504 married women in Northern Tanzania. We find that women who suffered a pregnancy loss show more tolerant views of partner violence (regr. coefficient -0.363; p-value: 0.001), and that child mortality lowers their perceived control over the sexual relationship with their spouse (odds ratio 0.262; p-value: 0.016). The number of children alive did not affect bodily integrity. These results confirm that women’s bodily integrity is partly dependent on the ability to fulfil their reproductive role. They strengthen the case for policies and programmes that improve women’s reproductive health, and underline the importance of counselling after pregnancy or child loss

Admixture mapping: from paradigms of race and ethnicity to population history

Admixture mapping is a whole genome association strategy that takes advantage of population history—or genetic ancestry—to map genes for complex diseases. However, because it uses racial/ethnic groupings to examine differential disease risk, admixture mapping raises ethical and social concerns. While there has been much theoretical commentary regarding the ethical and social implications of population-based genetic research, empirical data from stakeholders most closely involved with these studies is limited. One of the first admixture mapping studies carried out was a scan for Multiple Sclerosis (MS) risk factors in an African-American population. Applying qualitative research methods, we used this example to explore developing views, experiences and perceptions of the ethical and social implications of admixture mapping and other population-based research—their value, risks and benefits, and the future prospects of the field. Additionally, we sought to understand how social and ethical risks might be mitigated, and the benefits of this research optimized. We draw on in-depth, one-on-one interviews with leading population geneticists, genome scientists, bioethicists, and African-Americans with MS. Here we present our findings from this unique group of key informants and stakeholders

Recent Advances in Nanotechnology Applied to Biosensors

In recent years there has been great progress the application of nanomaterials in biosensors. The importance of these to the fundamental development of biosensors has been recognized. In particular, nanomaterials such as gold nanoparticles, carbon nanotubes, magnetic nanoparticles and quantum dots have been being actively investigated for their applications in biosensors, which have become a new interdisciplinary frontier between biological detection and material science. Here we review some of the main advances in this field over the past few years, explore the application prospects, and discuss the issues, approaches, and challenges, with the aim of stimulating a broader interest in developing nanomaterial-based biosensors and improving their applications in disease diagnosis and food safety examination

Adolescent-led marriage in Somaliland and Puntland: A surprising interaction of agency and social norms.

INTRODUCTION: Child marriage, formal and informal unions when one or both spouses are under 18, disproportionately affects adolescent girls over boys. It has serious consequences for girls' health, wellbeing, and development. Little is known about the ways in which girls' agency and contextual social norms - unwritten rules of (un)acceptable behaviour in a group - intersect to affect child marriage practices. This paper investigates norms and agency as facilitators and obstacles to adolescent girls' marriage in Somaliland and Puntland. METHODS: Participants (n = 156) were men and women living in Somaliland and Puntland. We conducted 36 qualitative semi-structured individual interviews (12 men and 24 women). We also held 15 focus group discussions (8 in Somaliland and 7 in Puntland) with 6-10 people each (n = 120). Mixed focus groups were conducted with men and women together, and were segregated by age. RESULTS: Technology and economic deprivation were important contextual factors in explaining the prevalence of child marriage. Participants reported that adolescent girls' and boys' increased agency contributed to, rather than decreased, child marriage. Access to technology expanded adolescents' freedom from their parents' control. Adolescents used that freedom within the existing system of social norms that rewarded early (as opposed to later) marriage. CONCLUSIONS: Effective interventions that aim to reduce marriage among adolescents living in Somalia (where marriage can be a protective strategy) should integrate a social norms perspective to avoid increasing adolescent-led marriage