The entropy of all systems is supposed to increase with time, this is also observed in the hydroclimatic records as increased variability. The current dissertation is primarily focused on the hydrologic variability of the hydrologic records in the climate regions across Continental United States. The study evaluated the effects of serial correlation in the historical streamflow records on both gradual trend and abrupt shift in streamflow. The study also evaluated the trend before and after the shift occurrence to validate whether the observed changes in streamflow is a result of long-term variability or climate regime shift. Secondly, the current dissertation evaluated the variability within western US hydrology which is highly driven by the oscillation of Pacific Ocean such as El Niño – Southern Oscillation (ENSO). The dissertation evaluated the variability in snow water equivalent (SWE) of western US as the winter snow accumulation of the region drives the spring-summer streamflow in the region which contributes to the major portion of yearly streamflow. The SWE variability during the individual phases of ENSO were analyzed to reveal the detailed influence of ENSO on historic snow accumulations. The study is not solely limited to the hydrologic variability evaluation rather; it also delves into obtaining the time lagged spatiotemporal teleconnections between large scale climate variables and streamflow and forecast the later based on the obtained teleconnections. To accomplish the research goals the current dissertation was subdivided into three research tasks. First task dealt with the streamflow records of 419 unimpaired streamflow records which were grouped into seven climate regions based on National Climate Assessment, to evaluate the regional changes in both seasonal streamflow and yearly streamflow percentiles. Non-parametric Mann-Kendall test and Pettitt’s test were utilized to evaluate the streamflow variability as gradual trend and abrupt shift, respectively. Walker test was performed to test the global significance of the streamflow variability within each climate regions based on local trend and shift significance of each streamflow stations. The task also evaluated the presence of serial correlation in the streamflow records and its effects on both trend and shift within the climate regions of continental United States for the first time. Maximum variability in terms of both trend and shift were observed for summer as compared to other seasons. Similarly, greater number of stations showed streamflow variability for 5th and 50th percentile streamflow as compared to 95th and 100th percentile streamflow. It was also observed that serial correlation affected both trend and step while, accounting for the lag-1 autocorrelation improved shift results. The results indicated that the streamflow variability has more likely occurred as shift as compared to the gradual trend. The outcomes of the current result detailing historic variability may help to envision future changes in streamflow. The second task evaluated the spatiotemporal variability of western US SWE over 58 years (1961–2018) as a trend and a shift. The task tested whether the SWE is consistent during ENSO phases utilizing the Kolmogorov – Smirnov (KS) test. Trend analysis was performed on the SWE data of each ENSO phase. Shift analysis was performed in the entire time series of 58 years. Additionally, the trend in the SWE data was evaluated before and after shift years. Mann- Kendal and Pettit's tests were utilized for the detection of trend and shift, respectively. The serial correlation was considered during the trend evaluation, while Thiel-Sen approach was used for the evaluation of the trend magnitude. The serial correlation in time series which is the potential cause of overestimation and underestimation of the trend evaluation was found to be absent in the SWE data. The results suggested a negative trend and a shift during the study period. The negative trend was absent during neutral years and present during El Niño and La Niña years. The trend magnitudes were maximum during La Niña years followed by those during El Niño years and the entire length of the data. It was also observed that if the presence of negative shift in the SWE was considered, then most of the stations did not show a significant trend before and after the occurrence of a shift. The third task forecasted the streamflow at a regional scale within Sacramento San Joaquin (SSJ) River Basin with largescale climate variables. SSJ is an agricultural watershed located in the drought sensitive region of California. The forecast techniques involved a hybrid statistical framework that eliminates the bias resulting from predefined indices at regional scale. The study was performed for eight unimpaired streamflow stations from 1962 to 2016. First, the Singular Valued Decomposition (SVD) teleconnections of the streamflow corresponding to 500 mbar geopotential height, sea surface temperature, 500 mbar specific humidity (SHUM500), and 500 mbar U-wind (U500) were obtained. Second, the skillful SVD teleconnections were screened non-parametrically. Finally, the screened teleconnections were used as the streamflow predictors in the non-linear regression models (K-nearest neighbor regression and data-driven support vector machine). The SVD results identified new spatial regions that have not been included in existing predefined indices. The nonparametric model indicated the teleconnections of SHUM500 and U500 being better streamflow predictors compared to other climate variables. The regression models were capable to apprehend most of the sustained low flows, proving the model to be effective for drought-affected regions. It was also observed that the forecasting approach showed better forecasting skills with preprocessed large-scale climate variables rather than using the predefined indices. The techniques involved in this task was simple, yet robust in providing qualitative streamflow forecasts that may assist water managers in making policy-related decisions when planning and managing watersheds.

This study resolves divergent prior findings relating book-tax differences to future earnings, determines whether prior literature has missed relationships between different types of book-tax differences and pre-tax and/or after-tax income, and investigates prior earnings as a factor contributing to the observed relationships. As past research has found that some firms have large book-tax differences over several years, this study separates these firms with large stable book-tax differences from others with large book-tax differences (non-stable) when investigating the link between large book-tax differences and future earnings. Finally, this study investigates whether the relationship between book-tax differences and future earnings reflects information about prior earnings and finds that prior earnings growth explains much of the lower persistence found for firms with large book-tax differences.

Community college leaders face challenges due to a lack of persistence data concerning 2-year colleges, especially in rural settings, prompting these leaders to turn to national data sets to drive local institutional changes. The purpose of this study was to identify variables associated with student place-frame and academic integration which are predictive of student persistence from the first to the second year in a small, residential community college in a rural frontier setting. Guided by Tinto's institutional departure theory, the theory of social representation, and Bassett's work in ruralism, a nonexperimental, correlational, quantitative research design was used to examine predictive relationships between student place-frame variables (age, sex, and intent to transfer), academic integration variables (student effort, collaborative learning, active learning, and academic challenge), and student persistence. Archival Community College Survey of Student Engagement data collected in 2013–2016 from 332 student participants were used for the study. Regression analysis showed a significant predictive relationship between student age and student intent to transfer with active learning. Additional binary logistical regression showed a significant positive relationship between active learning scores and student persistence. These findings informed development of evidence-based recommendations for programmatic changes to increase active learning practices, which could increase students' academic integration and persistence over time. By improving students' academic integration and persistence, positive social change may result through more students completing their degrees and their 2-year colleges gaining access to more substantial resources that are tied to student performance.

The purpose of this study was to identify those retention-associated variables which best account for persistence and nonpersistence among new full-time students in a community college. The major research question for the study was: Within a community college, what differentiates new full-time students who leave and those who stay? Do factors identified in previous studies which helped to explain persistence and nonpersistence in four-year colleges and universities and those colleges that serve large numbers of residential students hold the same power for explaining this phenomenon in community colleges? Of the 607 new full-time students who enrolled Fall Term, 1987, 552 were sent questionnaires at the end of the fourth week of Fall Term, 1987. Data within the persister and nonpersister groups were examined using chi-square and ANOVA. Discriminant analysis was used to study simultaneously the differences between persisters and nonpersisters with respect to several variables. The results of the study found statistically significant differences between persistence and nonpersistence and several community college students' background and environmental characteristics, and social and academic integration into a community college. This study also found among new full-time students who attend a community college, institutional and goal commitment contributed the most to group discrimination between persisters and nonpersisters. Future research of persisters and nonpersisters in community colleges was recommended. Implications for higher education practices was also suggested.

During the past few decades, research on student retention has been primarily focused on the constructs of social integration, lack of financial support and academic under-preparedness (Astin, 1975; Bean & Metzner, 1985; Cabrera, 1993; Pascarella,1982; Tinto, 1975). This study examined the phenomenal occurrence of low retention due to "lack of major and career direction." The Career Decision Scale and the Achievement Motivation Profile assessments were administered to 105 students at a comprehensive community college. Six linear regressions were conducted to determine if there were statistical relationships between:(a) career decision and the motivation to persist and; (b) career indecision and the lack of motivation to persist. Of the three regressions conducted on career decision and motivation to persist; two of the scores from the motivation profile indicated that a statistical relationship existed, whereas the third score did not. Of the three regressions conducted on career indecision and the lack of motivation to persist; two scores from the motivation profile indicated a statistical relationship between career indecision and the lack of motivation to persist, whereas the third score was not statistically significant. Recommendations were made to community colleges and universities to cultivate an environment where major and career decision initiatives become a top priority for students. Suggestions included creating courses in career planning and one-on-one career counseling sessions.

Many coaches are becoming aware of the importance of developing mentally tough performers and are designing programs to develop it in their athletes. One of the most significant problems in designing these programs is the inconsistency in the definition and description of mental toughness. If programs are to be designed with the goal of developing mental toughness in athletes, the components of the construct must be identified. Based on the advantages that mental toughness can offer to the performer, this study was designed to develop an understanding of the components of mental toughness in sport. The purpose of this study was to identify the components of mental toughness as perceived by National Collegiate Athletic Association (NCAA) coaches and was guided by two fundamental questions: what are the essential components of mental toughness? and to what degree are these components teachable (trainable). Twenty-two NCAA coaches were selected to participate from a mix of Division I, II, and III male sports teams. The procedures for this study were divided into a two-phase approach. Phase One consisted of each participant completing a questionnaire for the purpose of evaluating the importance and teachability (trainability) of 20 separate components of mental toughness. Phase Two consisted of follow-up, semi-structured interviews that provided further insight into the perspectives of the participants. The results of this study indicated the essential components of mental toughness based on their importance to the construct. The results also indicated the degree of teachability (trainability) of each component. A unique relationship between teachability and trainability was also revealed in this study. These findings provide a better understanding of the components of mental toughness and support the need for its development in sport. / Ph. D.

The purpose of this study was to examine achievement, retention, persistence, and success of Mississippi community college students who began in a developmental English course and eventually completed Composition I, a college-level course. This study examined the effects of utilizing online instruction via eLearning courses compared to traditional instructor-led instruction. The population of the study consisted of students enrolled in developmental English during the fall 2015 semester; and tracked their performance through the completion of Composition I. A Chi-Square test was utilized to address the each research question analyzing students’ use of a traditional face-toace instructional approach for developmental English and those using an online instructional approach for developmental English. The results show that students utilizing traditional instruction delivery for developmental English courses, out-performed students who took developmental English courses online in the areas of success, course retention and persistence rates. When measuring success in Composition I, the results were very close, however the online students had a higher percentage of passing grades 47.2%, when compared to traditional classroom students. Finally, when analyzing the results based on demographics, there was a higher percentage of students who passed the developmental course in the classroom when they are age 22 or younger, female, or black.

The purpose of this study was to develop a better understanding of factors that contribute to persistence in distance learning, and to provide program administrators with research-based recommendations on ways to improve retention rates and academic performance in an online graduate program for educators in the geosciences. This study used both quantitative and qualitative analysis to answer 5 research questions. The quantitative component of the study assessed whether student characteristics which could be identified and quantified through a premission screening correlated to persistence and academic success in the program. Data were collected through a voluntary survey administered during the program orientation. The qualitative component of the study consisted of interviews which were conducted to gain more concrete insights into the perceptions and practices of 2 student groups. The first group of interviewees was granted provisional admission with an undergraduate GPA under 2.75. Each went on to graduate with a cumulative GPA above 3.40. The students in the second group were put on academic probation for earning a course grade below a C early in the program and then went on to graduate. The results showed that there was not a statistically significant difference in the cumulative undergraduate GPA of those who persisted in the program versus those who withdrew or who were dismissed from the program. However, there was a significant difference in the undergraduate grades earned specifically in science courses. An unanticipated finding was that students who had not met with departmental faculty or program alumni were more than twice as likely to leave the program not in good academic standing. It appears that personal interaction is necessary for students to understand what is necessary be successful in the program. As such, administrators should consider incorporating more pre-program advising. It is evident that even students with a history of undergraduate academic success had misconceptions regarding the time commitment necessary to be academically successful. In addition, being a nontraditional student with a need to balance work, personal obligations, and extenuating circumstances was often a more important factor in performance and persistence than the online format of the program.

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