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BK1 and DCD1 Act Synergistically in Subsidiary Cell Formation in Zea Mays.

BK1 and DCD1 Act Synergistically in Subsidiary Cell Formation in Zea Mays.

Date: August 2014
Creator: Malhotra, Divya
Description: Subsidiary mother cell (SMC) divisions during stomatal complex formation in Zea mays are asymmetric generating a small subsidiary cell (SC) and a larger epidermal cell. Mutants with a high number of abnormally shaped subsidiary cells include the brick1 (brk1) and discordia1 (dcd1) mutants. BRK1 is homologous to HSPC300, an ARP2/3 complex activator, and is involved in actin nucleation while DCD1 is a regulatory subunit of the PP2A phosphatase needed for microtubule generation (Frank and Smith, 2002; Wright et al. 2009). Possible causes of the abnormal SCs in brk1 mutants include a failure of the SMC nucleus to polarize in advance of mitosis, no actin patch, and transverse and/or no PPBs (Gallagher and Smith, 2000; Panteris et al 2006). The abnormal subsidiary mother cell division in dcd1 is due to correctly localized, but disorganized preprophase bands (PPBs; Wright et al. 2009). The observation that brk1 has defects in PPB formation and that the dcd1 phenotype is enhanced by the application of actin inhibitors led us to examine the dcd1; brk1 double mutant (Gallagher and Smith, 1999). We found that dcd1; brk1 double mutants demonstrate a higher percentage of aberrant SCs than the single mutants combined suggesting that these two mutations have ...
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A Structural and Psychometric Evaluation of a Situational Judgment Test: The Workplace Skills Survey

A Structural and Psychometric Evaluation of a Situational Judgment Test: The Workplace Skills Survey

Date: August 2014
Creator: Wei, Min
Description: Some basic but desirable employability skills are antecedents of job performance. The Workplace Skills Survey (WSS) is a 48-item situational judgment test (SJT) used to assess non-technical workplace skills for both entry-level and experienced workers. Unfortunately, the psychometric evidence for use of its scores is far from adequate. The purpose of current study was two-fold: (a) to examine the proposed structure of WSS scores using confirmatory factor analysis (CFA), and (b) to explore the WSS item functioning and performance using item response theory (IRT). A sample of 1,018 Jamaican unattached youth completed the WSS instrument as part of a longitudinal study on the efficacy of a youth development program in Jamaica. Three CFA models were tested for the construct validity of WSS scores. Parameter estimations of item difficulty, item discrimination, and examinee’s proficiency estimations were obtained with item response theory (IRT) and plotted in item characteristics curves (ICCs) and item information curves (IICs). Results showed that the WSS performed quite well as a whole and provided precise measurement especially for respondents at latent trait levels of -0.5 and +1.5. However, some modifications of some items were recommended. CFA analyses showed supportive evidence of the one-factor construct model, while the six-factor ...
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Interaction of Plasmons and Excitons for Low-Dimension Semiconductors

Interaction of Plasmons and Excitons for Low-Dimension Semiconductors

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Date: December 2014
Creator: Lin, Jie
Description: The effects of surface plasmon for InGaN/GaN multi-quantum wells and ZnO nanoparticles optical linear and nonlinear emission efficiency had been experimentally studied. Due to the critical design for InGaN MQWs with inverted hexagonal pits based on GaN, both contribution of surface plasmon effect and image charge effect at resonant and off resonant frequencies were experimentally and theoretically investigated. With off- resonant condition, the InGaN MQWs emission significantly enhanced by metal nanoparticles. This enhancement was caused by the image charge effect, due to the accumulation of carriers to NPs region. When InGaN emission resonated with metal particles SP modes, surface Plasmon effect dominated the emission process. We also studied the surface plasmon effect for ZnO nanoparticles nonlinear optical processes, SHG and TPE. Defect level emission had more contribution at high incident intensity. Emissions are different for pumping deep into the bulk and near surface. A new assumption to increase the TPE efficiency was studied. We thought by using Au nanorods localized surface plasmon mode to couple the ZnO virtual state, the virtual state’s life time would be longer and experimentally lead the emission enhancement. We studied the TPE phenomena at high and near band gap energy. Both emission intensity and decay ...
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Sleep Duration, Sleep Insufficiency, and Carotid Intima-Media Thickness

Sleep Duration, Sleep Insufficiency, and Carotid Intima-Media Thickness

Date: May 2015
Creator: Dietch, Jessica R.
Description: Cardiovascular disease is the leading cause of death in the United States. Chronic short sleep duration is also a significant public health problem and has been linked to several markers and outcomes of cardiovascular disease. To date, inconsistency of assessments of sleep duration and insufficiency, use of covariates, and cardiovascular disease measurement across studies limits strong conclusions about the relationship between sleep duration, sleep insufficiency, and cardiovascular disease. The current study examined the association between sleep duration, sleep insufficiency, and a marker of preclinical coronary heart disease (i.e., carotid intima-media thickness) in a community sample using a cross-sectional design. Some evidence for a relationship between sleep duration and cIMT was found, with longer sleep duration predicting higher cIMT in some segments. Additionally, the interaction between sleep duration and sleep insufficiency was significant. However, neither of these effects were significant after adjusting for age and in some cases race/ethnicity, suggesting demographics may explain this association. Actigraphy and sleep diary duration assessments demonstrated significantly different correlations with cIMT in some segments, suggesting the nature of the assessment method may impact the strength or direction of the relationship between sleep duration and cIMT. Limitations and future directions are discussed.
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Deleterious Synergistic Effects of Concurrent Magnetic Field and Superparamagnetic (Fe3O4) Nanoparticle Exposures on CHO-K1 Cell Line

Deleterious Synergistic Effects of Concurrent Magnetic Field and Superparamagnetic (Fe3O4) Nanoparticle Exposures on CHO-K1 Cell Line

Date: May 2015
Creator: Coker, Zachary
Description: While many investigations have been performed to establish a better understanding of the effects that magnetic fields and nanoparticles have on cells, the fundamental mechanisms behind the interactions are still yet unknown, and investigations on concurrent exposure are quite limited in scope. This study was therefore established to investigate the biological impact of concurrent exposure to magnetic nanoparticles and extremely-low frequency magnetic fields using an in-vitro CHO-K1 cell line model, in an easily reproducible manner to establish grounds for further in-depth mechanistic, proteomic, and genomic studies. Cells were cultured and exposed to 10nm Fe3O4 nanoparticles, and DC or low frequency (0Hz, 50Hz, and 100Hz) 2.0mT magnetic fields produced by a Helmholtz coil pair. The cells were then observed under confocal fluorescence microscopy, and subject to MTT biological assay to determine the synergistic effects of these concurrent exposures. No effects were observed on cell morphology or microtubule network; however, cell viability was observed to decrease more drastically under the combined effects of magnetic field and nanoparticle exposures, as compared to independent exposures alone. It was concluded that no significant difference was observed between the types of magnetic fields, and their effects on the nanoparticle exposed cells, but quite clearly there are ...
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The Relationship of Peer Leadership Employment to Academic Outcomes in Texas Institutions of Higher Education

The Relationship of Peer Leadership Employment to Academic Outcomes in Texas Institutions of Higher Education

Date: May 2015
Creator: Buggs, Michelle L.
Description: The purpose of this quantitative study was to examine the relationship of participation and involvement in an undergraduate student success program to academic success and persistence among students in three programs sponsored by the Texas Higher Education Coordinating Board (THECB): the G-Force Collegiate Work-Study Mentorship Program, the Advancement Via Individual Determination (AVID) for Higher Education (AHE) program, and the THECB work-study program. The sample was identified using data from the THECB during the 2009-2013 academic years. Compared to THECB work-study students, significantly more AHE and G-Force students persisted toward graduation while engaged in the program (p < .001). ANOVA indicated that AHE students had a higher average GPA compared to G-Force and THECB work-study students, controlled for gender, race/ethnicity, pre-program GPA, and length of time in the position. Regression analyses found no statistically significant relationship between program associations and persistence towards graduation or GPA. Results suggest that although participation in a peer leadership programs such as AHE and G-Force encourage greater academic achievement and persistence, there is no direct relation to the achievement of these outcome variables. Implications of the study suggest the need for a deeper analysis into elements of peer leadership programs that contribute to student success, an ...
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The Nothingness of Presence: Sound, Ritual, and Encounter in the Music of Into Your Hands

The Nothingness of Presence: Sound, Ritual, and Encounter in the Music of Into Your Hands

Date: May 2015
Creator: Evans, Eric
Description: The ritual music written for the Compline service of the Liturgy of the Hours, Into Your Hands, is analyzed using an ontological and phenomenological approach, which seeks to answer how such sound/musical phenomena wed to the specific ritual dynamics of Compline in their own right can create a potential for encounter with the Divine. The Jewish philosopher Martin Buber’s understanding of encounter is used to show that the sound/musical phenomena in itself bears similarities with the nature of the Judeo/Christian God, and such a nature is revealed to be both irreducibly non-conceptual as well as an entity that establishes the ontological actuality of one’s being. Studies in the beginnings of humanity at large as well as the beginnings of the individual fetus reveal that an integrated expression of music and ritual can be said to have formed the impetus of such ontological beginnings through encounter. Therefore, one of the first sounds heard in the womb - that of water (or amniotic fluid) - constitutes what may be an archetypal sound of encounter. The phenomenological effects of such an archetype are analyzed in the music of Into Your Hands through topics such as the loss of aural perspective, immersion, dynamic swells, ...
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The Influence of Family and Cultural Values on the Career Development of Asian Americans

The Influence of Family and Cultural Values on the Career Development of Asian Americans

Date: August 2014
Creator: Sandhu, Gurminder
Description: Factors influencing the career development of Asian Americans have included family influences, including parental expectations and parent-young adult relationship, and adherence to Asian cultural values. Variables such as interests and values have been shown to be important factors in the career-related decisions of western, European American culture individuals, although interests have been found to be less important for Asian Americans. Research suggests that parental expectations and adherence to traditional Asian values have more influence on career development among this population. Sandhu found in 2011 that parental expectations are highly linked with career choice of a specific Asian subgroup. The current study examined the relationship between parental expectations, acculturation, career values, adherence to Asian cultural values, the parent-young adult relationship, and career choice in the Asian American population. The values gap between the parents’ and young adults’ cultural values as well as the gap’s effects on the parent-child relationship were assessed. A sample of 173 self-identified Asian Americans aged 18 to 25 were recruited from across the US to complete an Internet survey consisting of demographic questions, career choice questions, a measure of acculturation, an assessment of career-related values, an assessment of adherence to Asian cultural values, and an assessment of ...
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Criterion Validity of Common Career Interest Inventories: Relative Efficacy with High School Seniors.

Criterion Validity of Common Career Interest Inventories: Relative Efficacy with High School Seniors.

Date: August 2014
Creator: Martin, Summer M.G.
Description: Professional school counselors frequently use career interest inventories as part of a comprehensive guidance program to help students create a post-secondary school plan. The present study evaluates the validity of three commonly used interest inventories, the Myers-Briggs Type Indicator, Self-Directed Search, and Strong Interest Inventory on field of study choice for graduating high school seniors (N = 616) from a large, suburban high school in Texas. Students identified their intended postsecondary field of study category, were randomly assigned using stratification to three groups, and each group completed a different inventory. Group membership was evaluated to establish covariate balance on a wide variety of indicators. Data from each group was evaluated to determine the extent to which the inventory predicted the chosen field of study, as well as Other and Undeclared categories using logistic regression models. None of the inventory models suggest that the inventory accurately predicts Other or Undeclared outcomes. For students selecting intended postsecondary fields of study, the Self Directed Search predicts such outcomes better than other measures. Professional school and career counselors should consider the SDS in addition to narrative counseling strategies to add greater precision with career decision making among clients and students.
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A Construct Validity Analysis of the Work Perceptions Profile Data

A Construct Validity Analysis of the Work Perceptions Profile Data

Date: May 2015
Creator: Frear, Susan W.
Description: As work environments become more complex and demanding, organizations are becoming more interested in measuring the impact of their human resource development programs and initiatives. With this increased attention on data and measurement, human resource professionals have been encouraged to utilize data collection and data analysis techniques to make more objective and rationale human capital decisions and to verify business impact. As a result, the human resource profession has seen a significant increase in the use of surveys to measure anything from training effectiveness to the efficacy of recruitment procedures. The increase in the use of survey instruments requires that more focused attention is placed on the reliability and validity of data from any instrument used to make important human resource and business decisions. One instrument that is currently being used to measure career plateaus and job fit is the Work Perceptions Profile. The purpose of this research study was to conduct a construct validity analysis of the Work Perceptions Profile data and to determine the factor structure of data from its items. The data in this analysis supported a two-factor model structure with the first factor measuring Work Characteristics and a second factor measuring Performance. The results of this ...
Contributing Partner: UNT Libraries