This study examined a problem at a large community college in the Midwest United States, where African American students experienced poor developmental education outcomes and low degree completion. Those outcomes had negative effects on the institution and the surrounding community. This qualitative case study was framed in Astin's theory of involvement, which attributes students' behaviors, whether productive or unproductive, to their levels of motivation. Purposeful sampling was used to select 20 African American students who successfully completed the developmental education sequence. The participants were interviewed to determine how psychosocial factors impacted their decisions to persist through their courses. The data from the interviews were organized using coding software and then analyzed using a manual coding process. The data revealed that students' attitudes were the most influential in explaining their persistence. Having a positive, no-quit attitude was deeply salient among participants, and it helped them persist, despite obstacles and setbacks. Faculty influence was another factor that was deeply salient in the data, as most participants attributed their persistence to having positive relationships with faculty. In an effort to leverage this powerful dynamic to benefit more students, it was determined that a faculty training program would be the most effective way to address the problem at the case study site. The faculty training program is the culminating project for this study and is intended to equip faculty with strategies to promote more positive attitudes in students. This study and the resulting project may create positive social change by increasing degree attainment for underprepared African American students.

This study examined the relationship between intercollegiate participation and persistence in college. In addition, it explored the different factors that influenced student athletes' persistence patterns as compared to non-student athletes at residential liberal arts schools. Using data from the Wabash National Study of Liberal Arts Education (WNS), I first examined if student athletes were more likely to persist while controlling for background characteristics. Next, using Braxton's revised theory of student departure as a theoretical lens, I examined how eight factors (ability to pay, commitment of the institution to student welfare, communal potential, institutional integrity, proactive social adjustment, psychosocial engagement, social integration, and subsequent college commitment) influenced persistence in student athletes as compared to non-student athletes while controlling for students' backgrounds. The findings suggest that student athletes are more likely to persist. In addition, while Black students were more likely to persist than non-Black students as a whole, Black student athlete were less likely to persist than Black non-student athletes. Also, while some factors influenced student athletes and non-student athlete persistence patterns differently, no consistent pattern emerged. This study contributes to Braxton's model by suggesting classroom achievement, as measured by GPA, should be considered for inclusion in the model. Finally, this study has implications for administrators, especially those considering the use of athletics as an enrollment strategy.

Behavioral momentum theory (BMT) provides a theoretical framework for studying the persistence of behavior when challenged. The typical experimental arrangement to study persistence involves reinforcing a behavior according to a multiple schedules design. Unique schedules of reinforcement are programmed to each component. When steady-state responding occurs, the schedules of reinforcement are disrupted by a challenge condition (e.g., extinction, distraction, or prefeeding). The multiple schedules component that maintains the greatest level of responding during disruption is described as being more persistent. Basic research has shown that rate of reinforcement is a reliable predictor of persistence. The multiple schedules component associated with the higher rate of reinforcement persists longer than the multiple schedules component associated with the lower rate of reinforcement during disruption. Applied researchers have recently begun translating BMT to problems of social significance. The success of these initial translations suggests that relations between other dimensions of reinforcement and persistence should be studied. The current two-experiment study investigated the effect of quality of reinforcement on the persistence of task completion. Three participants with a history of engaging in problem behavior to escape from demands participated in Experiment I. After showing the conditions under which participants would and would not allocate away from a work task to engage with a preferred item, a baseline measure of task completion was obtained. Task completion was then reinforced with attention or tangibles within a multiple schedules design. Orange tokens signaled access to tangible reinforcement and yellow tokens signaled access to attention reinforcement. After steady-state responding occurred, preference for attention and tangibles was assessed within a concurrent schedules design. Extinction was then implemented to disrupt task completion within each component of the multiple schedules design. Results showed modest differences in the persistence of task completion with task completion in the multiple schedules component associated with the delivery of the more preferred reinforcer persisting longest. The modest differences in persistence were smaller than what has previously been shown in the literature. Thus, a follow-up experiment was conducted to evaluate the effect of reinforcer potency on the persistence of task completion. Three participants with a history of engaging in problem behavior to escape from demands participated in Experiment II. After identifying relatively more and less preferred stimuli with a multiple stimulus without replacement (MSWO) preference assessment, a unit price analysis was conducted to evaluate the potency of these two items within a concurrent schedules design. Task completion was then reinforced with the more and less potent reinforcers according to a multiple schedules design. After showing steady-state responding, task completion was disrupted by extinction. Results clearly showed greater persistence of task completion under the component associated with the delivery of the more potent reinforcer for two of three participants. Results from both experiments are discussed in terms of their conceptual and applied implications.

In this thesis we apply the idea of a barcode from persistent homology to four hierarchical clustering methods: single, average, complete, and Ward's linkage. Desirable theoretical properties of dendrograms, the standard tool to visualize the output of hierarchical clustering methods, were described by Carlsson. We define analogous properties for hierarchical clustering quasi-barcodes and prove that average and complete quasi-barcodes possess a property that dendrograms do not. We discuss how to decide where to "cut" the output of hierarchical clustering quasi-barcodes based on the distance between the heights at which clusters merge. We find the best possible matching for calculating the Wasserstein distance between quasi-barcodes built from the same number of data points all born at time 0. We also prove that single, average, and complete quasi-barcodes are stable in the sense that small perturbations in distances between points produce small changes in quasi-barcodes. In order to test the efficiency of quasi-barcodes and the cut-off criteria, we generate datasets of points arranged in blobs or concentric circles and look whether the combination of the quasi-barcode with the cut-off criteria successfully finds the right amount of clusters in the dataset and whether it places points in the correct clusters. Finally, we apply these tools to datasets from New York University and Peking University of typically developed controls and attention hyperactivity deficit disorder subjects between the ages of 7 and 18.

As the landscape of higher education changes to allow increased access for first-generation college students (FGS), emerging research should take into account the unique nature of this at-risk population of students (Aspelmeier, Love, McGill, Elliott, & Pierce, 2012). These students tend to be less prepared for the rigors of college coursework (Horn & Bobbitt, 2000; Strayhorn, 2006; Thayer, 2000) and may lack appropriate expectations (Pascarella, Pierson, Wolniak, & Terenzini, 2004). In particular, FGS may struggle with understanding the importance of creating and maintaining relationships with faculty (Cotten & Wilson, 2006; Davis, 2010). In order to discover any correlation between expectations for experiences with faculty and student success, as measured by cumulative first-year grade point average (GPA) and persistence to the second year of college, this study utilized Astin's Inputs-Environment-Outcomes (I-E-O) model. Astin's I-E-O model outlines the relationship between inputs, environment, and outcomes in order to understand student persistence in college (Astin & Sax, 1998; Thurmond & Popkess-Vawter, 2003). Although past researchers focused on the relationship between these inputs, experiences, and outcomes, the relationship of inputs (expectations) and outcomes (academic performance) has garnered less attention. Further, many focus on the disconnection between expectations and experiences; however, this study focuses solely on the expectations and its relationship with academic outcomes. The purpose of this research was to investigate the potential differences between first- and continuing-generation students' (CGS) expectations for faculty experiences and to discover any correlation between parental status and academic performance. This study utilized the College Student Expectations Questionnaire (CSXQ) in order to analyze 3,234 first-time in college students' expectations of faculty experiences during a summer 2008 orientation at a large, public, research intensive, metropolitan university located in West-Central Florida. The study also examined differences between FGS and CGS in first year college academic performance, while controlling for high school GPA. Further, the study assessed the relationship between FGS and CGS' expectations for faculty experiences and their academic performance after the first year of college, while controlling for high school GPA. Academic performance after the first year of college was measured as cumulative college grade point average and enrollment in the second year of college. The study analyzed secondary data in order to address seven research questions. No statistically significant differences were discovered between FGS and CGS' expectations for faculty experiences. Further, no statistically significant differences existed between FGS and CGS' academic performance, as measured by cumulative first year college grade point average and enrollment in the second year of college, while controlling for high school GPA. Lastly, weak relationships were discovered between FGS and CGS' expectations for faculty experiences and their academic performance after the first year of college. The study did not find statistically significant differences between FGS and CGS' academic performance, as measured by cumulative college grade point average and enrollment in the second year of college, while controlling for high school grade point average. Although strong relationships between expectations and academic performance were not revealed, these findings suggest that first- and continuing-generation college students may have other indicators or characteristics that impact their expectations. These indicators may correlate to academic performance measures including college GPA and enrollment in the second year.

Abstract not available

<p>Background: We have reason to believe that in fear of doing wrong; most PPM investors are crippled to stay passive. Hence, they are not using the full potential of the PPM systems. Some are lured in to use professional pension saving steward by promises of abnormal return. According to efficient market hypothesis this would be impossible, however, studies have shown that their might exist inherent financial anomalies that by the utilization of historic information can open the window for abnormal return.</p><p>Purpose: The purpose of the study is to draw attention to the problem of using ex ante data to predict ex post returns. Thus, we would have evaluated the practical implication of using ex ante data as a determinant in relation to optimal PPM funds selection, and if possible to provide some simplistic guidelines for the average PPM investor.</p><p>Results: We found a handful of portfolios that gave significant results against their own index; however, when tested against Sverige, rena and Global, Mix bolag the evidence of abnormal return were thin.  From our results, we conclude that their seems to be a persistence effect, as top achievers continued to perform above average in almost all cases, however, one could not profitize on abnormal return other than by chance.  Consequently, historic return can give the investor an aid in optimal portfolio selection. Historic figures concerning standard deviation, expense ratios, and load fees all significantly correlated with return, however, neither seem to give the investor an edge in optimal PPM portfolio selection.</p>

Flax (Linum usitatissimum L.) is being considered as a platform crop for the development of bioproducts. Potential benefits of bioindustrial farming include the provison of bioenergy and biomaterials, and opportunities for biorefining. Prior to the commercialization of crops intended for bioproducts however, the safety of the food/feed system and the environment must be assured. As part of a preliminary biosafety assessment I conducted a literature review and experiments to quantify seed-mediated gene flow from flax to the environment and food/feed system. Flax seed losses at harvest, seed persistence in soil, efficacy of herbicides to control volunteer survival and fecundity in subsequent crops, volunteerism (density and occurrence) and volunteer emergence periodicity in follow crops in commercial fields were examined. Total seed losses at harvest in commercial fields were variable (2.7 to 44.2 kg ha-1). Flax has a short longevity in the seed bank (2 to 3 years). Flax has been selected for reduced seed dormancy and volunteer flax seed persistence may be hastened by burial. Compared to other domesticated crops, flax has a prolonged period of emergence and calculated EM50 values (the growing degree days required for 50% emergence) ranged from 227 to 340 growing degree days (GDD). Flax volunteers reached their period of peak emergence earlier in conventional tillage than in reduced tillage fields. Volunteer flax densities were highest prior to herbicide applications (10.4 to 570.2 plants m-2) in all fields the year following flax production (2005) and diminished over time. Volunteers that emerge in the spring may be controlled with registered herbicides. Glyphosate and fluroxypyr tank-mixed with either monohydrate sodium salt of 2,4-dicholorophenoxy acetic acid (2,4-D) or monochlorophenoxyacetic acid Ester 500 (MCPA) were most effective in reducing volunteer flax density, biomass, and fecundity. These herbicides also reduced the adventitious presence of volunteer flax seed in spring wheat (from over 8.5% to 0.16%). Best management practices could be adopted to mitigate seed-mediated gene flow from flax in agricultural productions systems, but thresholds of zero are not biologically realistic. The agronomic baseline data generated in this thesis however, suggests that flax may be an appropriate crop platform for bioindustrial products. / Plant Science

Dengue (pronounced den'guee) Fever (DF) and Dengue Hemorrhagic Fever (DHF), collectively known as "dengue," are mosquito-borne, potentially mortal, flu-like viral diseases that affect humans worldwide. Transmitted to humans by the bite of an infected mosquito, dengue is caused by any one of four serotypes, or antigen-specific viruses. In this thesis, both the spatial and temporal dynamics of dengue transmission are investigated. Different chapters present new models while building on themes of previous chapters. In Chapter 2, we explore the temporal dynamics of dengue viral transmission by presenting and analyzing an ODE model that combines an SIR human host- with a multi-stage SI mosquito vector transmission system. In the case where the juvenile populations are at carrying capacity, juvenile mosquito mortality rates are sufficiently small to be absorbed by juvenile maturation rates, and no humans die from dengue, both the analysis and numerical simulations demonstrate that an epidemic will persist if the oviposition rate is greater than the adult mosquito death rate. In Chapter 3, we present and analyze a non-autonomous, non-linear ODE system that incorporates seasonality into the modeling of the transmission of the dengue virus. We derive conditions for the existence of a threshold parameter, the basic reproductive ratio, denoting the expected number of secondary cases produced by a typically infective individual. In Chapter 4, we present and analyze a non-linear system of coupled reaction-diffusion equations modeling the virus' spatial spread. In formulating our model, we seek to establish the existence of traveling wave solutions and to calculate spread rates for the spatial dissemination of the disease. We determine that the epidemic wave speed increases as average annual, and in our case, winter, temperatures increase. In Chapter 5, we present and analyze an ODE model that incorporates two serotypes of the dengue virus and allows for the possibility of both primary and secondary infections with each serotype. We obtain an analytical expression for the basic reproductive number, R_0, that defines it as the maximum of the reproduction numbers for each strain/serotype of the virus. In each chapter, numerical simulations are conducted to support the analytical conclusions.

The diversity of choices we have to make everyday influence our environment and ourselves in more ways than most of us realise. Anthropogenic substances, such as flame retardants, date back as early as 450 BC when the Egyptians used alum to reduce flammability. The increasing demand for new articles has led to an increased production of chemical substances, for which many are commercially produced without complete knowledge on properties such as persistence, bioaccumulation and toxicology (PBT). Commercial compounds may be properly tested and denominated as “safe” regarding PBT properties, but their degradation products and/or metabolites may cause environmental impact. The availability of uniform and accurate data for prediction of persistence is of key importance for the understanding of chemical fate. A method to determine the susceptibility of chemicals to undergo oxidation in water has been developed and applied on several organohalogens, including PBDEs and OH-PBDEs. The method was used to determine reaction rates and the group of OH-PBDEs were subsequently subjected to photolysis by use of UV-light. Hence, susceptibility to undergo both oxidation and photolysis for the OH-PBDEs were investigated and compared to previously reported degradation rates on PBDEs. As a final step in promoting the prediction of persistence, Quantitative structure-property relationship (QSPR) models were performed on a set of compounds which had undergone photolytic degradation under similar conditions. The QSPRs were used as a preliminary step in predicting photolysis half-lives for chemical substances and to determine which physicochemical descriptors are of greatest importance thereof. This thesis presents the possibility of performing and assessing oxidation transformations on compounds of low and high water solubility, photolysis transformations in various media and using obtained data to predict behaviour via QSPR models, to promote predictions of persistence.