8 resultados para Three-wave interaction
em Digital Commons at Florida International University
Resumo:
This study was designed to address questions regarding the effects of sex and leadership style on teacher perceptions of principal effectiveness. On a researcher-designed instrument, middle school teachers rated the effectiveness of a scenario principal's response in several situations. The responses reflected varying levels of Task and Relationship Behavior.^ The design incorporated two between subjects factors (Teacher Sex and Principal Sex) and one within subjects factor (Leadership Style) which was treated as a repeated measure. An analysis of variance revealed no significant effects except for Leadership Style. Overall, High Task/High Relationship behavior rated significantly higher and Low Task/Low Relationship rated significantly lower than the others. The null hypothesis concerning differences could not be rejected and the stated research hypotheses were not supported.^ Additional analyses of variance were conducted substituting subject demographic variables for Teacher Sex in the research design. No significant interactions or main effects other than Leadership Style were noted when either Age or Ethnicity were substituted.^ A significant two-way interaction was noted for Teacher Experience and Leadership Style (p =.0316). Less experienced teachers rated principal's performance lower when exhibiting High Task/Low Relationship style than did more experienced teachers. A significant three-way interaction was noted for Administrative Aspiration x Principal Sex x Leadership Style (p =.0294). Teachers who indicated an intent to enter administration differed more on their ratings between male and female principals exhibiting mixed styles of High Task/Low Relationship and Low Task/High Relationship than did teachers who indicated no or undecided.^ Sex of the teacher appears less important than sex of the principal on performance ratings. Results suggest further study of the effects of teacher experience and teacher administrative aspiration on perceptions of principal effectiveness. ^
Resumo:
This study was designed to address questions regarding the effects of sex and leadership style on teacher perceptions of principal effectiveness. On a researcher-designed instrument, middle school teachers rated the effectiveness of a scenario principal's response in several situations. The responses reflected varying levels of Task and Relationship Behavior. The design incorporated two between subjects factors (Teacher Sex and Principal Sex) and one within subjects factor (Leadership Style) which was treated as a repeated measure. An analysis of variance revealed no significant effects except for Leadership Style. Overall, High Task/High Relationship behavior rated significantly higher and Low Task/Low Relationship rated significantly lower than the others. The null hypothesis concerning differences could not be rejected and the stated research hypotheses were not supported. Additional analyses of variance were conducted substituting subject demographic variables for Teacher Sex in the research design. No significant interactions or main effects other than Leadership Style were noted when either Age or Ethnicity were substituted. A significant two-way interaction was noted for Teacher Experience and Leadership Style (p = .0316). Less experienced teachers rated principal's performance lower when exhibiting High Task/Low Relationship style than did more experienced teachers. A significant three-way interaction was noted for Administrative Aspiration x Principal Sex x Leadership Style (p = .0294). Teachers who indicated an intent to enter administration differed more on their ratings between male and female principals exhibiting mixed styles of High Task/Low Relationship and Low Task/High Relationship than did teachers who indicated no or undecided. Sex of the teacher appears less important than sex of the principal on performance ratings. Results suggest further study of the effects of teacher experience and teacher administrative aspiration on perceptions of principal effectiveness.
Resumo:
The major objective of this study was to determine the relative importance of landscape factors, local abiotic factors, and biotic interactions in influencing tadpole community structure in temporary wetlands. I also examined the influence of agricultural activities in South-central Florida by comparing tadpole communities in native prairie wetlands (a relatively unmodified habitat) at the Kissimmee Prairie Sanctuary (KPS) to tadpole communities in three agriculturally modified habitats found at MacArthur Agro-Ecology Research Center (MAERC). Environmental characteristics were measured in 24 isolated wetlands, and tadpoles were sampled using throw-traps and dipnets during the 1999 wet season (June–October). Landscape characteristics were expected to predominately influence all aspects of community structure because anurans associated with temporary wetland systems are likely to exist as metapopulations. Both landscape characteristics (wetland proximity to nearest woodland and the amount of woodland surrounding the wetland) and biotic interactions (fish predation) had the largest influence on tadpole community structure. Predatory fish influenced tadpole communities more than expected due to the ubiquity of wetlands, lack of topographic relief, and dispersal abilities of several fish species. Differences in tadpole community structure among habitat types were attributed to differences in woodland attributes and susceptibility to fish colonization. Furthermore, agricultural modification of prairie habitats in South-central Florida may benefit amphibian communities, particularly woodland-dwelling species that are unable to coexist with predatory fish. From a conservation standpoint, temporary wetlands proximal to woodland areas and isolated from permanent water sources appear to be most important to amphibians. In addition, the high tadpole densities attained in these wetlands suggest that these wetlands serve as biological hotspots within the landscape, and their benefits extend into the adjacent terrestrial matrix. Further research efforts are needed to quantify the biological productivity of these systems and determine spatial dynamics of anurans in surrounding terrestrial habitats. ^
Resumo:
The beginning of the 21st century was plagued with unprecedented instances of corporate fraud. In an attempt to address apparent non-existent or “broken” corporate governance policies, sweeping measures of financial reporting reform ensued, having specific requirements relating to the composition of audit committees, the interaction between audit committees and external auditors, and procedures concerning auditors’ assessment of client risk. The purpose of my dissertation is to advance knowledge about “good” corporate governance by examining the association between meeting-or-beating analyst forecasts and audit fees, audit committee compensation, and audit committee tenure and “busyness”. Using regression analysis, I found the following: (1) the frequency of meeting-or-just beating (just missing) analyst forecasts is negatively (positively) associated with audit fees, (2) the extent by which a firm exceeds analysts’ forecasts is positively (negatively) associated with audit committee compensation that is predominately equity-based (cash-based), and (3) the likelihood of repeatedly meeting-or-just beating analyst forecasts is positively associated with audit committee tenure and “busyness”. These results suggest that auditors consider clients who frequently meet-or-just beat forecasts as being less “risky”, and clients that frequently just miss as being more “risky”. The results also imply that cash-based director compensation is more successful in preserving the effectiveness of the audit committee’s financial reporting oversight role, that equity-based compensation motivates independent audit committee directors to focus on short-term performance thereby aligning their interests with management, and that audit committee director tenure and the degree of director “busyness” can affect an audit committee member’s effectiveness in providing financial reporting oversight. Collectively, my dissertation provides additional insights regarding corporate governance practices and informs policy-makers for future relevant decisions.^
Resumo:
This study investigated Microteaching Lesson Study (MLS) and three possible MLS mentor interaction structures during the debriefing sessions in relation to elementary preservice teacher development of knowledge for teaching. One hundred three elementary preservice teachers enrolled in five different sections of a mathematics methods course at a southern urban university were part of the study. This included 72 participants who completed MLS across three different mentor interaction structures as part of their course requirements and 31 elementary preservice teachers who did not complete MLS as part of their methods course and served as a comparison group for a portion of the study. A sequential mixed-methods research design was used to analyze the relationship between MLS mentor interaction structure and growth in preservice teachers' mathematics teacher knowledge. Data sources included pre and post assessments, group developed lesson plans and final reports, a feedback survey with Likert-type and open-ended questions, and transcripts of audio-recorded debriefing sessions. The pre and post assessments were analyzed using Analysis of Variance (ANOVA) and descriptive statistics were used to analyze the Likert-type feedback survey questions. Group MLS lesson plans, final reports, and transcripts of debriefing sessions along with the open-ended questions from the feedback survey were coded in a three-step process as described by Miles and Huberman (1994). In alignment with findings from M. Fernandez (2005, 2010), elementary preservice teachers participating in MLS grew in content knowledge related to MLS topics taught by one another. Results from the analysis of pre and post content knowledge assessments revealed that participants grew in their understanding of the mathematics topics taught during MLS irrespective of their mentor interaction structure and when compared to the participants who did not complete MLS in their methods course. Findings from the analysis of lesson plans for growth in pedagogical content knowledge revealed the most growth in this area occurred for participants assigned to the interaction structure in which the MLS mentor participated in the first two debriefing sessions. Analysis of the transcripts of the discourse during the debriefing sessions and the feedback surveys support the finding that the elementary preservice teachers assigned to the interaction structure in which the MLS mentor participated in the first and second debriefing sessions benefited more from the MLS experience when compared to elementary preservice teachers assigned to the other two interaction structures (MLS mentor participated in only the first debriefing session and MLS mentor participated in only the last debriefing session).
Resumo:
The major objective of this study was to determine the relative importance of landscape factors, local abiotic factors, and biotic interactions in influencing tadpole community structure in temporary wetlands. I also examined the influence of agricultural activities in South-central Florida by comparing tadpole communities in native prairie wetlands (a relatively unmodified habitat) at the Kissimmee Prairie Sanctuary (KPS) to tadpole communities in three agriculturally modified habitats found at MacArthur Agro- Ecology Research Center (MAERC). Environmental characteristics were measured in 24 isolated wetlands, and tadpoles were sampled using throw-traps and dipnets during the 1999 wet season (June - October). Landscape characteristics were expected to predominately influence all aspects of community structure because anurans associated with temporary wetland systems are likely to exist as metapopulations. Both landscape characteristics (wetland proximity to nearest woodland and the amount of woodland surrounding the wetland) and biotic interactions (fish predation) had the largest influence on tadpole community structure. Predatory fish influenced tadpole communities more than expected due to the ubiquity of wetlands, lack of topographic relief, and dispersal abilities of several fish species. Differences in tadpole community structure among habitat types were attributed to differences in woodland attributes and susceptibility to fish colonization. Furthermore, agricultural modification of prairie habitats in South-central Florida may benefit amphibian communities, particularly woodland-dwelling species that are unable to coexist with predatory fish. From a conservation standpoint, temporary wetlands proximal to woodland areas and isolated from permanent water sources appear to be most important to amphibians. In addition, the high tadpole densities attained in these wetlands suggest that these wetlands serve as biological hotspots within the landscape, and their benefits extend into the adjacent terrestrial matrix. Further research efforts are needed to quantify the biological productivity of these systems and determine spatial dynamics of anurans in surrounding terrestrial habitats.
Resumo:
The current study implements a speech perception experiment that interrogates local perceptions of Spanish varieties in Miami. Participants (N=292) listened to recordings of three Spanish varieties (Peninsular, Highland Colombian, and Post-Castro Cuban) and were given background information about the speakers, including the parents’ country of origin. In certain cases, the parents’ national-origin label matched the country of origin of the speaker, but otherwise the background information and voices were mismatched. The manipulation distinguishes perceptions determined by bottom-up cues (dialect) from top-down ones (social information). Participants then rated each voice for a range of personal characteristics and answered hypothetical questions about the speakers’ employment, family, and income. Results show clear top-down effects of the social information that often drive perceptions up or down depending on the traits themselves. Additionally, the data suggest differences in perceptions between Hispanic/non-Hispanic and Cuban/non-Cuban participants, although the Cuban participants do not drive the Hispanic participants’ perceptions.
Resumo:
The purpose of this research was to develop a theory of high-energy exclusive electrodisintegration of three-nucleon systems on the example of 3He(e, e'NN)N reaction with knocked-out nucleon in the final state. The scattering amplitudes and differential cross section of the reaction were calculated in details within the Generalized Eikonal Approximation(GEA). The manifestly covariant nature of Feynman diagrams derived in GEA allowed us to preserve both the relativistic dynamics and kinematics of the scattering while identifying the low momentum nuclear part of the amplitude with a nonrelativistic nuclear wave function. Numerical calculations of the residual system's total and relative momentum distribution were performed which show reasonable agreement with available experimental data. The theoretical framework of GEA, which was applied previously only for the case of two-body (deuteron) high energy break up reactions, has been practically implemented and shown to provide a valid description for more complex A = 3 systems.