The theory of margin as a predictor of success on the National Council Licensure Examination for Registered Nurses

The National Council Licensure Examination for Registered Nurses (NCLEX-RN) is the examination that all graduates of nursing education programs must pass to attain the title of registered nurse. Currently the NCLEX-RN passing rate is at an all-time low (81%) for first-time test takers (NCSBN, 2004); amidst a nationwide shortage of registered nurses (Glabman, 2001). Because of the critical need to supply greater numbers of professional nurses, and the potential accreditation ramifications that low NCLEX-RN passing rates can have on schools of nursing and graduates, this research study tests the effectiveness of a predictor model. This model is based upon the theoretical framework of McClusky's (1959) theory of margin (ToM), with the hope that students found to be at-risk for NCLEX-RN failure can be identified and remediated prior to taking the actual licensure examination. To date no theory based predictor model has been identified that predicts success on the NCLEX-RN. ^ The model was tested using prerequisite course grades, nursing course grades and scores on standardized examinations for the 2003 associate degree nursing graduates at a urban community college (N = 235). Success was determined through the reporting of pass on the NCLEX-RN examination by the Florida Board of Nursing. Point biserial correlations tested model assumptions regarding variable relationships, while logistic regression was used to test the model's predictive power. ^ Correlations among variables were significant and the model accounted for 66% of variance in graduates' success on the NCLEX-RN with 98% prediction accuracy. Although certain prerequisite course grades and nursing course grades were found to be significant to NCLEX-RN success, the overall model was found to be most predictive at the conclusion of the academic program of study. The inclusion of the RN Assessment Examination, taken during the final semester of course work, was the most significant predictor of NCLEX-RN success. Success on the NCLEX-RN allows graduates to work as registered nurses, reflects positively on a school's academic performance record, and supports the appropriateness of the educational program's goals and objectives. The study's findings support potential other uses of McClusky's theory of margin as a predictor of program outcome in other venues of adult education. ^

Statistical analysis and optimal classification of blood cell populations using Gaussian distributions

This dissertation develops a new figure of merit to measure the similarity (or dissimilarity) of Gaussian distributions through a novel concept that relates the Fisher distance to the percentage of data overlap. The derivations are expanded to provide a generalized mathematical platform for determining an optimal separating boundary of Gaussian distributions in multiple dimensions. Real-world data used for implementation and in carrying out feasibility studies were provided by Beckman-Coulter. It is noted that although the data used is flow cytometric in nature, the mathematics are general in their derivation to include other types of data as long as their statistical behavior approximate Gaussian distributions. ^ Because this new figure of merit is heavily based on the statistical nature of the data, a new filtering technique is introduced to accommodate for the accumulation process involved with histogram data. When data is accumulated into a frequency histogram, the data is inherently smoothed in a linear fashion, since an averaging effect is taking place as the histogram is generated. This new filtering scheme addresses data that is accumulated in the uneven resolution of the channels of the frequency histogram. ^ The qualitative interpretation of flow cytometric data is currently a time consuming and imprecise method for evaluating histogram data. This method offers a broader spectrum of capabilities in the analysis of histograms, since the figure of merit derived in this dissertation integrates within its mathematics both a measure of similarity and the percentage of overlap between the distributions under analysis. ^

The Influence of Phosphorus on Periphyton Mats from the Everglades and Three Tropical Karstic Wetlands

The distinctive karstic, freshwater wetlands of the northern Caribbean and Central American region support the prolific growth of calcite-rich periphyton mats. Aside from the Everglades, very little research has been conducted in these karstic wetlands, which are increasingly threatened by eutrophication. This study sought to (i) test the hypothesis that water depth and periphyton total phosphorus (TP) content are both drivers of periphyton biomass in karstic wetland habitats in Belize, Mexico and Jamaica, (ii) provide a taxonomic inventory of the periphytic diatom species in these wetlands and (iii) examine the relationship between periphyton mat TP concentration and diatom assemblage at Everglades and Caribbean locations. ^ Periphyton biomass, nutrient and diatom assemblage data were generated from periphyton mat samples collected from shallow, marl-based wetlands in Belize, Mexico and Jamaica. These data were compared to a larger dataset collected from comparable sites within Everglades National Park. A diatom taxonomic inventory was conducted on the Caribbean samples and a combination of ordination and weighted-averaging modeling techniques were used to compare relationships between periphyton TP concentration, periphyton biomass and diatom assemblage composition among the locations. ^ Within the Everglades, periphyton biomass showed a negative correlation with water depth and mat TP, while periphyton mat percent organic content was positively correlated with these two variables. These patterns were also exhibited within the Belize, Mexico and Jamaica locations, suggesting that water depth and periphyton TP content are both drivers of periphyton biomass in karstic wetland systems within the northern Caribbean region. ^ A total of 146 diatom species representing 39 genera were recorded from the three Caribbean locations, including a distinct core group of species that may be endemic to this habitat type. Weighted averaging models were produced that effectively predicted mat TP concentration from diatom assemblages for both Everglades (R2=0.56) and Caribbean (R2=0.85) locations. There were, however, significant differences among Everglades and Caribbean locations with respect to species TP optima and indicator species. This suggests that although diatoms are effective indicators of water quality in these wetlands, differences in species response to water quality changes can reduce the predictive power of these indices when applied across systems. ^

The effects of biofeedback on the occurrence of urinary incontinence in patients following radical retropubic prostatectomy

Postprostatectomy incontinence can create a significant barrier to the attainment of optimal social and physical functioning postoperatively. The objective of this retrospective, descriptive study was to determine the effect of biofeedback on the incidence of urinary incontinence in men status post radical retropubic prostatectomy (RRP). All patients of a urologic practice who had a biofeedback session preoperatively, and two sessions postoperatively, were sent a survey to complete. Correlational analysis concluded that there was no significance (p > .05) between a subject's age, educational level, or adherence to biofeedback therapy, and their level of postprostatectomy incontinence. Of those subjects who participated (n = 46), 35% reported their urinary control as excellent, 50% reported good results, and 15% reported fair results. No subjects reported poor urinary control. Ninety-five percent of subjects said they would recommend the biofeedback treatment to a friend, and 88% felt that biofeedback had helped them attain their present level of urinary control.