The primary purpose of this Delphi study was to determine which of the research-identified differentiated instructional elements are the most effective for improving student performance as perceived by secondary principals in 2A to 5A 2009 ―Exemplary‖ public high schools in Texas. A secondary purpose for this study was to determine what additional differentiated instructional elements are perceived by this study‘s targeted principals as being critical for student success. The researcher obtained feedback during three Delphi survey rounds from the twenty-four member expert panel regarding which of the research-identified differentiated instructional elements they perceived to be the most effective for improving student performance. The differentiated instructional elements presented in the survey were based upon a sound theoretical framework resulting from a review of existing research on differentiated instruction. After Round Three, consensus was reached, and the data collection period ended. Each of the surveys for the study, as well as the statistical analysis, can be found in the appendices of this dissertation. The findings of this study determined that using a variety of resources, as well as a variety of strategies, were the top-ranked research-identified differentiated instructional elements that the expert panel perceived to be the most effective for improving student performance. In addition, panelists agreed that the differentiated instructional elements already identified in existing research, as presented in this study, are comprehensive and sufficient for improving student performance. Without a doubt, the conclusions and recommendations of this study could extend the current knowledge base by promoting the use of the most effective research-identified differentiated instructional elements to improve student performance. Furthermore, the implications of the study will be invaluable for ongoing professional development, principal and teacher preparation programs, and for those in the field seeking to improve their daily educational practices for student impact.

Role theory is generally presented as a way of describing human interactions. Role dynamics describes the psychosocial phenomenon in terms of the various roles and role components being played and actively manipulated as a part of interpersonal interactions. The concept of role offers a general unit of interaction involving a complex of behaviour, expectation, and overt or covert consensual agreement. Therefore, roles can be thought of as expectations one has about social behaviour and as functions or positions. Groups are fundamental to human behaviour - without them individuals would have great difficulty surviving. People thrive on the interdependent relationships they find in groups. In some groups you participate as a leader, while in others you assume the role of follower. In many ways, the groups you have chosen to join reflect your interests and what motivates you. Group dynamics refers to the interactions within a group that characterize the group. The dynamics of the group can be fostered through good leadership as well, and the processes involved are most effective when they facilitate the group toward meeting its goal. The concept of leadership is a central building block of the conventional wisdom of organization and management. The definition of leadership leads to a variety of possibilities, which leads to the conclusion that the definition of leadership should depend on the purposes to be Served by the definition. One complex definition that has evolved, delineates effective leadership as the interaction among members of a group that initiates and maintains improved expectations and the competence of the group to solve problems or to attain goals. A general weakness of higher education has been its inability or unwillingness to make constructive and consistent use of student leadership as an advocate for the institution. From the perspective of student leadership, the fact that student advocacy is rarely utilized to its full potential represents a significant missed opportunity among our nation's universities. If the potential for leadership among these students were systematically cultivated, a new and powerful voice could be created that would go far in helping universities explain their missions and needs to lawmakers, the media and the voting public. Little research has been reported on student organizations. Literature involving student organizations dealt with the role organizations play in student involvement and student development. Reported research on the use of organization development in university student organizations described new practices, programmes and techniques for working with student organizations but did not reflect attempts to measure the effectiveness of interventions. This research provides readers with additional opportunities to explore the characteristics of effective groups and leaders and the leadership process. It is intended to move student leaders beyond the theory of leadership and closer to the world of practice and application. The major objectives of the study are: 0 How effectively and autonomously do student councils function as groups at tertiary institutions and how prepared are the members of the student councils to assume the leadership role? Are there statistical significant differences between biographical variables and the variables of group effectiveness, autonomy and leadership? Is there a relationship between group effectiveness, autonomy and leadership? The research study is divided into a theoretical and empirical framework. Various aspects of role theory, groups and leadership outline the theoretical basis. The empirical study is carried out by way of a questionnaire and the data is analysed according to specific statistical methods. The empirical study was conducted amongst members of student councils at different tertiary institutions in South Africa. The major findings of the study supported the set of research objectives and were the following: Group effectiveness It has been determined that most student councils at tertiary institutions in the study population are aware of their mission, are satisfied with achieving their goals, take possession, communicate openly and honest with members and have clear roles and norms. Autonomy Most of the student councils at tertiary institutions in the study population have satisfactory autonomy regarding work methods, work scheduling and work criteria. Leadership Student councils at tertiary institutions in the study population are prepared to assume their leadership roles. Differences between biographical variables and group effectiveness, autonomy and leadership Perceivable differences between gender and leadership in the student councils at tertiary institutions in the study population exist but are of no statistical significance. The relationship between the subvariables of group effectiveness, autonomy and leadership It has been determined that there is a relationship between the subvariables of group effectiveness and autonomy. No practical statistic significance relationships have been determined between leadership and autonomy for the study population. Further research on leadership as a process of group dynamics is recommended. / Thesis (M.A. (Industrial Psychology))--North-West University, Potchefstroom Campus, 2004.

Field experiments were conducted in Kentucky and Louisiana in 2008 and 2009 (split-plot in a randomized complete block design with four replications) to investigate it is possible to simulate with manual defoliation the effect of soybean rust (SBR) (Phakopsora pachyrhizi Syd. and P. Syd) injury on a healthy soybean [Glycine max, (L.) Merr.] canopy, understand how defoliation affects the growth dynamics and canopy light interception, and if defoliation affectsleaf senescence and nitrogen remobilization during the seed-filling period. Two manual defoliation treatments based on changes in effective leaf area index (ELAI) (calculated as the reduction in leaf area equivalent to SBR-induced premature leaf abscission, loss in green leaf area, and reduction in photosynthetic capacity of diseased leaves) in infected canopies in Brazil were used to simulate SBR infection at growth stage R2 (full flowering) and R5 (beginning of seed-fill). Both defoliation treatments reduced yield in all experiments and the reduction was larger for the treatments at growth stage R2. The yield losses were equivalent to that observed in infected soybean canopies in Brazil. This suggests that a system of manual defoliation to simulate changes in effective leaf area duration shows promise as a tool to simulate the impact of SBR on soybean yield. The radiation use efficiency and crop growth rate from growth stage R2 to R5 were not influenced by defoliation. Defoliation started at growth stage R2 reduced seed number per unit area, while defoliation started at growth stage R5 reduced seed size due to shortening the seed-fill duration and a lower seed growth rate. There is no evidence that manual defoliation affected leaf senescence or nitrogen redistribution to the seed. This study found that the reduction of light interception by SBR was the main reason for the reductions in soybean growth and yield.

The purpose of this study was to investigate the importance of effective school leadership. The study was conducted in senior secondary schools in the southern region of Botswana. The southern region comprises of the south and south central regions which has twelve (12) senior secondary schools, out of which seven (07) schools were randomly sampled for the study. Both interviews and questionnaires were used as research tools. One hundred and eighty nine (189) questionnaires were distributed and only one hundred and four (104) were completed and returned. Eight interviews were conducted among school leaders. Results from the questionnaires were analyzed using frequencies, percentages and tables. Results from the interview were analyzed within a framework that was structured along the lines of the research questions. The study reveals that most of the teachers have a teaching qualification (PGDE), have adequate teaching experience, and are generally young (30-35 years). In terms of position of responsibility, most of them are clustered around senior teacher II (42.3%) and teacher/educator (36.5%). The study also reveals that schools performance is hampered largely by indiscipline and laziness towards schoolwork by both stakeholders. The school leaders must act as catalysts in creating a learning environment and be actively involved in implementing improvement strategies that help both students and teachers to enhance their learning and achievement (cf. 2. 16. 2). / Thesis (M.Ed)--North-West University, Mafikeng Campus, 2007

The purpose of this study was to investigate the importance of effective school leadership. The study was conducted in senior secondary schools in the southern region of Botswana. The southern region comprises of the south and south central regions which has twelve (12) senior secondary schools, out of which seven (07) schools were randomly sampled for the study. Both interviews and questionnaires were used as research tools. One hundred and eighty nine (189) questionnaires were distributed and only one hundred and four (104) were completed and returned. Eight interviews were conducted among school leaders. Results from the questionnaires were analyzed using frequencies, percentages and tables. Results from the interview were analyzed within a framework that was structured along the lines of the research questions. The study reveals that most of the teachers have a teaching qualification (PGDE), have adequate teaching experience, and are generally young (30-35 years). In terms of position of responsibility, most of them are clustered around senior teacher II (42.3%) and teacher/educator (36.5%). The study also reveals that schools performance is hampered largely by indiscipline and laziness towards schoolwork by both stakeholders. The school leaders must act as catalysts in creating a learning environment and be actively involved in implementing improvement strategies that help both students and teachers to enhance their learning and achievement (cf. 2. 16. 2). / Thesis (M.Ed)--North-West University, Mafikeng Campus, 2007

Role theory is generally presented as a way of describing human interactions. Role dynamics describes the psychosocial phenomenon in terms of the various roles and role components being played and actively manipulated as a part of interpersonal interactions. The concept of role offers a general unit of interaction involving a complex of behaviour, expectation, and overt or covert consensual agreement. Therefore, roles can be thought of as expectations one has about social behaviour and as functions or positions. Groups are fundamental to human behaviour - without them individuals would have great difficulty surviving. People thrive on the interdependent relationships they find in groups. In some groups you participate as a leader, while in others you assume the role of follower. In many ways, the groups you have chosen to join reflect your interests and what motivates you. Group dynamics refers to the interactions within a group that characterize the group. The dynamics of the group can be fostered through good leadership as well, and the processes involved are most effective when they facilitate the group toward meeting its goal. The concept of leadership is a central building block of the conventional wisdom of organization and management. The definition of leadership leads to a variety of possibilities, which leads to the conclusion that the definition of leadership should depend on the purposes to be Served by the definition. One complex definition that has evolved, delineates effective leadership as the interaction among members of a group that initiates and maintains improved expectations and the competence of the group to solve problems or to attain goals. A general weakness of higher education has been its inability or unwillingness to make constructive and consistent use of student leadership as an advocate for the institution. From the perspective of student leadership, the fact that student advocacy is rarely utilized to its full potential represents a significant missed opportunity among our nation's universities. If the potential for leadership among these students were systematically cultivated, a new and powerful voice could be created that would go far in helping universities explain their missions and needs to lawmakers, the media and the voting public. Little research has been reported on student organizations. Literature involving student organizations dealt with the role organizations play in student involvement and student development. Reported research on the use of organization development in university student organizations described new practices, programmes and techniques for working with student organizations but did not reflect attempts to measure the effectiveness of interventions. This research provides readers with additional opportunities to explore the characteristics of effective groups and leaders and the leadership process. It is intended to move student leaders beyond the theory of leadership and closer to the world of practice and application. The major objectives of the study are: 0 How effectively and autonomously do student councils function as groups at tertiary institutions and how prepared are the members of the student councils to assume the leadership role? Are there statistical significant differences between biographical variables and the variables of group effectiveness, autonomy and leadership? Is there a relationship between group effectiveness, autonomy and leadership? The research study is divided into a theoretical and empirical framework. Various aspects of role theory, groups and leadership outline the theoretical basis. The empirical study is carried out by way of a questionnaire and the data is analysed according to specific statistical methods. The empirical study was conducted amongst members of student councils at different tertiary institutions in South Africa. The major findings of the study supported the set of research objectives and were the following: Group effectiveness It has been determined that most student councils at tertiary institutions in the study population are aware of their mission, are satisfied with achieving their goals, take possession, communicate openly and honest with members and have clear roles and norms. Autonomy Most of the student councils at tertiary institutions in the study population have satisfactory autonomy regarding work methods, work scheduling and work criteria. Leadership Student councils at tertiary institutions in the study population are prepared to assume their leadership roles. Differences between biographical variables and group effectiveness, autonomy and leadership Perceivable differences between gender and leadership in the student councils at tertiary institutions in the study population exist but are of no statistical significance. The relationship between the subvariables of group effectiveness, autonomy and leadership It has been determined that there is a relationship between the subvariables of group effectiveness and autonomy. No practical statistic significance relationships have been determined between leadership and autonomy for the study population. Further research on leadership as a process of group dynamics is recommended. / Thesis (M.A. (Industrial Psychology))--North-West University, Potchefstroom Campus, 2004.

In this thesis jet production and cosmological constraints on decaying dark matter are studied. The powerful framework of effective field theory is applied in both cases to further our knowledge of particle physics. We first discuss how to apply the Soft Collinear Effective Theory (SCET) for calculating hadronic jet production rate. By applying SCET power counting, we develop a consistent approach to perform phase space integrations. This approach is then successfully applied to one-loop calculations with regard to a variety of jet algorithms. This allows us to study if the soft contribution can be factorized from the collinear ones. In particular we point out the connection between such factorization and the choice of ultraviolet regulator. We then further our study of the (exclusive) kt and C/A jet algorithms in SCET with the introduction of an additional regulator. Regularizing the virtualities and rapidities of graphs in SCET, we are able to write the next-to-leading-order dijet cross section as the product of separate hard, jet, and soft contributions. We show how to reproduce the Sudakov form factor to next-to-leading logarithmic accuracy previously calculated by the coherent branching formalism. Our resummed expression only depends on the renormalization group evolution of the hard function, rather than on that of the hard and jet functions as is usual in SCET. Finally we present a complete analysis of the cosmological constraints on decaying dark matter. For this, we have updated and extended previous analyses to include Lyman-alpha forest, large scale structure, and weak lensing observations. Astrophysical constraints are not considered in this thesis. The bounds on the lifetime of decaying dark matter are dominated by either the late-time integrated Sachs-Wolfe effect for the scenario with weak reionization, or CMB polarisation observations when there is significant reionization. For the respective scenarios, the lifetimes for decaying dark matter are constrained by Gamma^{-1} > 100 Gyr and (f*Gamma)^{-1} > 5.3 x 10^8 Gyr (at 95.4% confidence level), where the phenomenological parameter f is the fraction of decay energy deposited into the baryonic gas. This allows us to constrain particle physics models with dark matter candidates, by analyzing effective operators responsible for the dark matter decays into Standard Model particles.

In this thesis jet production and cosmological constraints on decaying dark matter are studied. The powerful framework of effective field theory is applied in both cases to further our knowledge of particle physics. We first discuss how to apply the Soft Collinear Effective Theory (SCET) for calculating hadronic jet production rate. By applying SCET power counting, we develop a consistent approach to perform phase space integrations. This approach is then successfully applied to one-loop calculations with regard to a variety of jet algorithms. This allows us to study if the soft contribution can be factorized from the collinear ones. In particular we point out the connection between such factorization and the choice of ultraviolet regulator. We then further our study of the (exclusive) kt and C/A jet algorithms in SCET with the introduction of an additional regulator. Regularizing the virtualities and rapidities of graphs in SCET, we are able to write the next-to-leading-order dijet cross section as the product of separate hard, jet, and soft contributions. We show how to reproduce the Sudakov form factor to next-to-leading logarithmic accuracy previously calculated by the coherent branching formalism. Our resummed expression only depends on the renormalization group evolution of the hard function, rather than on that of the hard and jet functions as is usual in SCET. Finally we present a complete analysis of the cosmological constraints on decaying dark matter. For this, we have updated and extended previous analyses to include Lyman-alpha forest, large scale structure, and weak lensing observations. Astrophysical constraints are not considered in this thesis. The bounds on the lifetime of decaying dark matter are dominated by either the late-time integrated Sachs-Wolfe effect for the scenario with weak reionization, or CMB polarisation observations when there is significant reionization. For the respective scenarios, the lifetimes for decaying dark matter are constrained by Gamma^{-1} > 100 Gyr and (f*Gamma)^{-1} > 5.3 x 10^8 Gyr (at 95.4% confidence level), where the phenomenological parameter f is the fraction of decay energy deposited into the baryonic gas. This allows us to constrain particle physics models with dark matter candidates, by analyzing effective operators responsible for the dark matter decays into Standard Model particles.

Theoretical predictions for generic multi-scale observables in Quantum Chromodynamics (QCD) typically suffer from large Sudakov logarithms associated with the emission of soft or collinear radiation, whose presence spoils the perturbative expansion in the coupling strength which underlies most calculations in QCD. A canonical way to improve predictions wherever these logarithms appear is to resum them to all perturbative orders, which can conveniently be achieved using Effective Field Theory (EFT) methods. In an age of increasing automation using computers, this task is still mostly performed manually, observable-by-observable. In this thesis we identify the 2-loop soft function as a crucial ingredient for the resummation of QCD Sudakov logarithms to Next-to-next-to-leading logarithmic (NNLL) accuracy in Soft-Collinear Effective Theory (SCET), for wide classes of observables involving two massless colour-charged energetic particles, such as dijet event shapes at lepton colliders, or colour singlet production at hadron colliders. We develop a method to evaluate these soft functions using numerical methods based on sector decomposition and the choice of a convenient parametrisation for the phase space. This allows the factorisation of all implicit (real emission) and explicit (virtual correction) divergences made manifest by dimensional and analytic regularisation. The regulator pole coefficients can then be evaluated numerically following a subtraction and expansion, and two computational tools are presented to perform these numerical integrations, one based on publicly available tools, the other based on our own code. Some technical improvements over naive straightforward numerical evaluation are demonstrated and implemented. This allows us to compute and verify two of three colour structures of the 2-loop bare soft functions for wide ranges of observables with a factorisation theorem. A number of example results - both new and already known - are shown to demonstrate the reach of this approach, and a few possible extensions are sketched. This thesis therefore represents a crucial step towards automation of resummation for generic observables to NNLL accuracy in SCET.

In this thesis, we use the Coleman-Weinberg effective potential for computing the radiative corrections to scalar masses in six simple models of the quantum field theory. We probe, for example, the theory of two scalar fields, simple generalizations of the Abelian Higgs model or some classic extensions of the Standard Model. A common feature of all the theories considered is the existence of (at least) two mass scales different in order of magnitude. Being motivated by the hierarchy problem, we study mainly the sensitivity of light scalar masses on the radiative corrections induced by the heavy fields in relevant Feynman loops. We demonstrate that while the masses of scalars with zero VEV obtain corrections proportional to the masses of the heavy fields, in theories with the spontaneous symmetry breakdown is the Higgs mass always governed by the corresponding ordering parameter, i.e., by its vacuum expectation value. For the Standard Model, understood as an effective field theory, this implies that the Higgs boson mass is as stable with respect to the effects of possible new physics on very high energies as the masses of the leptons, quarks, W and Z bosons. Powered by TCPDF (www.tcpdf.org)