Conservation implications of the reproductive biology of the endangered vine Ipomoea microdactyla Griseb. (Convolvulaceae)

A plant's reproductive biology exerts a significant influence on both population persistence within changing environments and successful establishment of new populations. However, the interaction between extrinsic (i.e. ecological) and intrinsic (i.e. genetic) factors also is an important driver of demographic performance for plant populations. It is light of this that I performed a multidisciplinary investigation of the breeding system, seed and seedling establishment dynamics, and population genetic structure of the endangered Caribbean vine Ipomoea microdactyla Griseb. (Convolvulaceae). The results from the breeding system study show individuals from Florida, USA and Andros Island, Bahamas to be self-incompatible. Plants from the two regions are cross-compatible but there is evidence for outbreeding depression in their progeny. Significant regional differences were found in floral traits and progeny traits that suggests incipient speciation for the Florida populations. The results from the seed and seedling establishment dynamics experiment demonstrate that the restoration of small populations in Florida via seed and seedling augmentation is a successful strategy. The demographic performance of the outplanted individuals was driven significantly by ecological factors (e.g. herbivory) rather than by genetic factors which emphasizes that the ecological context is very important for successful restoration attempts. The results from the population genetic study using an analysis of molecular variation (AMOVA) reveal significant differences in genetic variation among individuals from Florida, Andros, and Cuba. A Bayesian analysis of population genetic structuring coincided with the previous AMOVA results among the three regions. The Mantel test indicated significant 'isolation by distance' for these regional populations implying restricted gene flow over relatively short distances. Overall, the Florida populations had the lowest measures of genetic diversity which is most likely due to the effects of both colonization founder events and habitat fragmentation. The results of my study highlight the value of performing multidisciplinary studies in relation to species conservation as knowledge of both extrinsic and intrinsic factors can best guide decisions for species preservation.

The analytical determination of the uniqueness and persistence of the volatile components of human scent using optimized collection methods

The Locard exchange principle proposes that a person can not enter or leave an area or come in contact with an object, without an exchange of materials. In the case of scent evidence, the suspect leaves his scent in the location of the crime scene itself or on objects found therein. Human scent evidence collected from a crime scene can be evaluated through the use of specially trained canines to determine an association between the evidence and a suspect. To date, there has been limited research as to the volatile organic compounds (VOCs) which comprise human odor and their usefulness in distinguishing among individuals. For the purposes of this research, human scent is defined as the most abundant volatile organic compounds present in the headspace above collected odor samples. ^ An instrumental method has been created for the analysis of the VOCs present in human scent, and has been utilized for the optimization of materials used for the collection and storage of human scent evidence. This research project has identified the volatile organic compounds present in the headspace above collected scent samples from different individuals and various regions of the body, with the primary focus involving the armpit area and the palms of the hands. Human scent from the armpit area and palms of an individual sampled over time shows lower variation in the relative peak area ratio of the common compounds present than what is seen across a population. A comparison of the compounds present in human odor for an individual over time, and across a population has been conducted and demonstrates that it is possible to instrumentally differentiate individuals based on the volatile organic compounds above collected odor samples. ^

Development and testing of the Elderly Social Vulnerability Index (ESVI): A composite indicator to measure social vulnerability in the Jamaican elderly population

Over the last two decades social vulnerability has emerged as a major area of study, with increasing attention to the study of vulnerable populations. Generally, the elderly are among the most vulnerable members of any society, and widespread population aging has led to greater focus on elderly vulnerability. However, the absence of a valid and practical measure constrains the ability of policy-makers to address this issue in a comprehensive way. This study developed a composite indicator, The Elderly Social Vulnerability Index (ESVI), and used it to undertake a comparative analysis of the availability of support for elderly Jamaicans based on their access to human, material and social resources. The results of the ESVI indicated that while the elderly are more vulnerable overall, certain segments of the population appear to be at greater risk. Females had consistently lower scores than males, and the oldest-old had the highest scores of all groups of older persons. Vulnerability scores also varied according to place of residence, with more rural parishes having higher scores than their urban counterparts. These findings support the political economy framework which locates disadvantage in old age within political and ideological structures. The findings also point to the pervasiveness and persistence of gender inequality as argued by feminist theories of aging. Based on the results of the study it is clear that there is a need for policies that target specific population segments, in addition to universal policies that could make the experience of old age less challenging for the majority of older persons. Overall, the ESVI has displayed usefulness as a tool for theoretical analysis and demonstrated its potential as a policy instrument to assist decision-makers in determining where to target their efforts as they seek to address the issue of social vulnerability in old age. Data for this study came from the 2001 population and housing census of Jamaica, with multiple imputation for missing data. The index was derived from the linear aggregation of three equally weighted domains, comprised of eleven unweighted indicators which were normalized using z-scores. Indicators were selected based on theoretical relevance and data availability.

Predicting the in-term persistence of community college English-as-a-second-language students

The English-as-a-second-language (ESL) community college student population has increased notably in the past decade, but a decreasing number of these students are completing courses, programs, or degrees (Erisman & Looney, 2008). These students come to college with unique background experiences, and once in college, deal with challenging linguistic, academic, and social integration issues. Though they are not linguistically homogenous, and they do not have a common purpose, ESL students share the common goal of attending community college to learn to speak English (Szelényi & Chang, 2002). Course completion is a primary measure of progress toward that goal, and is therefore an issue of concern for both ESL students and community colleges, which continue to be the access point for language-minority students progressing into higher education (Laden, 2004).^ The purpose of this study was to investigate the factors that predict in-term persistence of community college ESL students. A mixed methods research design consisting of two phases was utilized, and participants in this study were ESL students enrolled in a large community college in south Florida. Phase 1 students completed the Community College ESL Student Questionnaire (CCSEQ), which collected demographic data and data on entry characteristics, academic integration, and social integration. Discriminant and descriptive analyses were used to report the data collected in Phase I. Phase 2 students were a matching cohort of completing and non-completing students who participated in semi-structured interviews at the end of the term. Data collected in the interviews were analyzed thematically, using a constant comparative method as described by Glaser and Strauss (1967).^ Students’ self reported demographic data, background characteristics, goal commitment, and integration factors on the CCSEQ showed no significance between the students who completed the term and the students who did not complete the term. However, several differentiating themes emerged from the interview data, which indicated differences in goal commitment and integration between the two groups. The focus of non-completers on getting good grades rather than completing the course, and the commitment of completers to the goal of finishing the class in order to go forward, both raise questions for future research studies.^

Development and Testing of the Elderly Social Vulnerability Index (ESVI): A Composite Indicator to Measure Social Vulnerability in the Jamaican Elderly Population

Over the last two decades social vulnerability has emerged as a major area of study, with increasing attention to the study of vulnerable populations. Generally, the elderly are among the most vulnerable members of any society, and widespread population aging has led to greater focus on elderly vulnerability. However, the absence of a valid and practical measure constrains the ability of policy-makers to address this issue in a comprehensive way. This study developed a composite indicator, The Elderly Social Vulnerability Index (ESVI), and used it to undertake a comparative analysis of the availability of support for elderly Jamaicans based on their access to human, material and social resources. The results of the ESVI indicated that while the elderly are more vulnerable overall, certain segments of the population appear to be at greater risk. Females had consistently lower scores than males, and the oldest-old had the highest scores of all groups of older persons. Vulnerability scores also varied according to place of residence, with more rural parishes having higher scores than their urban counterparts. These findings support the political economy framework which locates disadvantage in old age within political and ideological structures. The findings also point to the pervasiveness and persistence of gender inequality as argued by feminist theories of aging. Based on the results of the study it is clear that there is a need for policies that target specific population segments, in addition to universal policies that could make the experience of old age less challenging for the majority of older persons. Overall, the ESVI has displayed usefulness as a tool for theoretical analysis and demonstrated its potential as a policy instrument to assist decision-makers in determining where to target their efforts as they seek to address the issue of social vulnerability in old age. Data for this study came from the 2001 population and housing census of Jamaica, with multiple imputation for missing data. The index was derived from the linear aggregation of three equally weighted domains, comprised of eleven unweighted indicators which were normalized using z-scores. Indicators were selected based on theoretical relevance and data availability.