The Wielandt subgroup, the intersection of normalizers of subnormal subgroups, is non-trivial in any finite group and thus gives rise to a series whose length is a measure of the complexity of a group's subnormal structure. Another measure, akin to the nilpotency class of nilpotent groups, arises from the strong Wielandt subgroup, the intersection of centralizers of nilpotent subnormal sections. This thesis begins an investigation into how these two invariants relate in finite soluble groups. ¶ Complete results are obtained for metabelian groups of odd order: the strong Wielandt length of such a group is at most one more than its Wielandt length, and this bound is best possible. Some progress is made in the wider class of groups with p-length 1 for all primes p. A conjecture for all finite soluble groups, which may be regarded as a subnormal analogue of the embedding of the Kern, is also considered.

The objectives of the present study were to: (a) replicate the results of Arthur et al. (2002) by comparing race-based subgroup differences on a multiple-choice and constructed response test in a laboratory setting using a larger sample, (b) extend their work by investigating the role of reading ability, test-taking skills, and test perceptions that could explain why subgroup differences are reduced when the test format is changed from multiple-choice to a constructed response format, and (c) assess the criterion-related validity of the constructed response test. Two hundred sixty White and 204 African Americans completed a demographic questionnaire, Test Attitudes and Perceptions Survey, a multiple-choice or constructed response test, the Raven's Advanced Progressive Matrices Short Form, the Nelson-Denny Reading Test, Experimental Test of Testwiseness, and a post-test questionnaire. In general, the pattern of results supported the hypotheses in the predicted direction. For example, although there was a reduction in subgroup differences in performance on the constructed response compared to the multiple-choice test, the difference was not statistically significant. However, analyses by specific test content yielded a significant reduction in subgroup differences on the science reasoning section. In addition, all of the hypothesized study variables, with the exception of face validity, were significantly related to test performance. Significant subgroup differences were also obtained for all study variables except for belief in tests and stereotype threat. The results also indicate that reading ability, test-taking skills, and perceived fairness partially mediated the relationship between race and test performance. Finally, the criterion-related validity for the constructed response test was stronger than that for the multiple-choice test. The results suggested that the constructed response test format investigated in the present study may be a viable alternative to the traditional multiple-choice format in high-stakes testing to solve the organizational dilemma of using the most valid predictors of job performance and simultaneously reducing subgroup differences and subsequent adverse impact on tests of knowledge, skill, ability, and achievement. However, additional research is needed to further demonstrate the appropriateness of the constructed response format as an alternative to traditional testing methods.

In the present research, I examined individuals' evaluative responses toward traditional representations of environmentalists (e.g., tree-huggers and radical activists) as well as less typical but more mainstream environmentalists. Undergraduate students read about one of three types of environmentalists (i.e., radical activist, tree-hugger, or mainstream environmentalist). Participants then rated the extent to which they liked the individual they read about. Results revealed that participants evaluated the tree-hugger and radical activist less favourably than a typical student. In contrast, participants responded as favourably toward the mainstream environmentalist as they did toward a typical student. These findings indicate that individuals have distinct impressions of different types of environmentalists: Whereas mainstream environmentalists may receive favourable evaluations from individuals, stereotypical environmentalists may elicit negative reactions and even alienate members of the public.

In the present research, I examined individuals' evaluative responses toward traditional representations of environmentalists (e.g., tree-huggers and radical activists) as well as less typical but more mainstream environmentalists. Undergraduate students read about one of three types of environmentalists (i.e., radical activist, tree-hugger, or mainstream environmentalist). Participants then rated the extent to which they liked the individual they read about. Results revealed that participants evaluated the tree-hugger and radical activist less favourably than a typical student. In contrast, participants responded as favourably toward the mainstream environmentalist as they did toward a typical student. These findings indicate that individuals have distinct impressions of different types of environmentalists: Whereas mainstream environmentalists may receive favourable evaluations from individuals, stereotypical environmentalists may elicit negative reactions and even alienate members of the public.

The objectives of the present study were to: (a) replicate the results of Arthur et al. (2002) by comparing race-based subgroup differences on a multiple-choice and constructed response test in a laboratory setting using a larger sample, (b) extend their work by investigating the role of reading ability, test-taking skills, and test perceptions that could explain why subgroup differences are reduced when the test format is changed from multiple-choice to a constructed response format, and (c) assess the criterion-related validity of the constructed response test. Two hundred sixty White and 204 African Americans completed a demographic questionnaire, Test Attitudes and Perceptions Survey, a multiple-choice or constructed response test, the Raven's Advanced Progressive Matrices Short Form, the Nelson-Denny Reading Test, Experimental Test of Testwiseness, and a post-test questionnaire. In general, the pattern of results supported the hypotheses in the predicted direction. For example, although there was a reduction in subgroup differences in performance on the constructed response compared to the multiple-choice test, the difference was not statistically significant. However, analyses by specific test content yielded a significant reduction in subgroup differences on the science reasoning section. In addition, all of the hypothesized study variables, with the exception of face validity, were significantly related to test performance. Significant subgroup differences were also obtained for all study variables except for belief in tests and stereotype threat. The results also indicate that reading ability, test-taking skills, and perceived fairness partially mediated the relationship between race and test performance. Finally, the criterion-related validity for the constructed response test was stronger than that for the multiple-choice test. The results suggested that the constructed response test format investigated in the present study may be a viable alternative to the traditional multiple-choice format in high-stakes testing to solve the organizational dilemma of using the most valid predictors of job performance and simultaneously reducing subgroup differences and subsequent adverse impact on tests of knowledge, skill, ability, and achievement. However, additional research is needed to further demonstrate the appropriateness of the constructed response format as an alternative to traditional testing methods.

Made available in DSpace on 2015-09-17T15:24:28Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-08-12. Added 1 bitstream(s) on 2015-09-17T15:47:47Z : No. of bitstreams: 1 000844745.pdf: 560125 bytes, checksum: 6adc853f60c4ad9ad7a288228990dea7 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / No presente trabalho comprometemo-nos ao estudo de soluções clássicas para D-branas no espaço de Anti-de Sitter, as quais surgem da solução de órbita do subgrupo estabilizador de um ponto na fronteira no espaço AdS. Começamos por fazer uma breve revisão da teoria de supercordas e apresentamos algumas características da geometria do espaço AdS. Então fazemos uma discussão sobre a ação efetiva a baixas energias e, por último, escrevemos a ação de uma D3-brana no espaço AdS5. O estudo desta solução particular da D-brana não é completo e acaba por fugir ao escopo deste trabalho. Esperamos complementá-lo num futuro breve e, com isto em mente, concluímos a dissertação com um resumo de deformações marginais da teoria de campo N = 4 SYM e sua gravidade dual / The main result of this dissertation is the study of the classical solutions for D-brane in Anti-de Sitter(AdS) space. They arised from the study of the orbit solution of the stablizer subgroup of a point on the boundary of the AdS space. To reach this goal we started making a brief summary of superstring theories, then we presented some geometric facts of the AdS space. A discussion of the effective low-energy action of a bosonic D-brane was done, then we wrote the action of a single D3-brane in the AdS5 space. Unfortunately, the study of this particular D-brane solution is not complete and goes beyond the scope of this dissertation. We intend to complete this work in the future, with this in mind a summary of the marginal deformation of N = 4 SYM field theory and its gravity dual were given in the last chapter / CAPES: 33015015001P7

Orientador: Andrey Yuryevich Mikhaylov / Banca: Nathan Jacob Berkovits / Banca: Vladimir Perchine / Resumo: No presente trabalho comprometemo-nos ao estudo de soluções clássicas para D-branas no espaço de Anti-de Sitter, as quais surgem da solução de órbita do subgrupo estabilizador de um ponto na fronteira no espaço AdS. Começamos por fazer uma breve revisão da teoria de supercordas e apresentamos algumas características da geometria do espaço AdS. Então fazemos uma discussão sobre a ação efetiva a baixas energias e, por último, escrevemos a ação de uma D3-brana no espaço AdS5. O estudo desta solução particular da D-brana não é completo e acaba por fugir ao escopo deste trabalho. Esperamos complementá-lo num futuro breve e, com isto em mente, concluímos a dissertação com um resumo de deformações marginais da teoria de campo N = 4 SYM e sua gravidade dual / Abstract: The main result of this dissertation is the study of the classical solutions for D-brane in Anti-de Sitter(AdS) space. They arised from the study of the orbit solution of the stablizer subgroup of a point on the boundary of the AdS space. To reach this goal we started making a brief summary of superstring theories, then we presented some geometric facts of the AdS space. A discussion of the effective low-energy action of a bosonic D-brane was done, then we wrote the action of a single D3-brane in the AdS5 space. Unfortunately, the study of this particular D-brane solution is not complete and goes beyond the scope of this dissertation. We intend to complete this work in the future, with this in mind a summary of the marginal deformation of N = 4 SYM field theory and its gravity dual were given in the last chapter / Mestre

Subgrouping is a mixing technique that most mix engineers use. Little research on perceptual evaluations of mixing techniques has been done and what little research that has, has been done on automatic mixing systems. When it comes to research on subgrouping in automatic mixing systems the results show a significant preference towards automatic mixes with subgroups over mixes without. This study aims to test the same notion that the use of subgroups improves listener preference but this time in mixes created by humans. A group of mix engineers created two mixes of one song, one with the use of subgroups and one without. These mixes were the stimuli of a listening experiment that was conducted to investigate listener preference of mixes with and without subgroups as well as what perceived qualities were most prevalent in preferred mixes and mixes with and without subgroups. The results showed that mixes without subgroups were preferred over mixes with subgroups, although, these results were not statistically significant. The results also showed that balance, frequency and clarity were the most prevalent sonic qualities that helped the listeners decide how to rank the mixes.

This thesis is a study of the subgroup structure of some remarkable groups of automorphisms of rooted trees. It is divided into two parts. The main result of the first part is seemingly of an algorithmic nature, establishing that the Gupta--Sidki 3-group G has solvable membership problem. This follows the approach of Grigorchuk and Wilson who showed the same result for the Grigorchuk group. The proof, however, is not algorithmic, and it moreover shows a striking subgroup property of G: that all its infinite finitely generated subgroups are abstractly commensurable with either G or G × G. This is then used to show that G is subgroup separable which, together with some nice presentability properties of G, implies that the membership problem is solvable. The proof of the main theorem is also used to show that G satisfies a "strong fractal" property, in that every infinite finitely generated subgroup acts like G on some rooted subtree. The second part concerns the subgroup structure of branch and weakly branch groups in general. Motivated by a natural question raised in the first part, a necessary condition for direct products of branch groups to be abstractly commensurable is obtained. From this condition it follows that the Gupta--Sidki 3-group is not abstractly commensurable with its direct square. The first main result in the second part states that any (weakly) branch action of a group on a rooted tree is determined by the subgroup structure of the group. This is then applied to answer a question of Bartholdi, Siegenthaler and Zalesskii, showing that the congruence subgroup property for branch and weakly branch groups is independent of the actions on a tree. Finally, the information obtained on subgroups of branch groups is used to examine which groups have an essentially unique branch action and why this holds.

Soit G un groupe algébrique réel simple de rang réel au moins 2 et P un sous-groupe parabolique de G. On montre que tout sous-groupe discret de G intersectant le radical unipotent de P en un réseau est un réseau aritmétique de G, sauf éventuellement lorsque G = SO(2,4n+2) et P est le stabilisateur d'un 2-plan isotrope. Ceci répond partiellement à une conjecture de Margulis, déjà étudiée par Hee Oh. On étudie aussi le cas où G est le produit de plusieurs groupes de rang 1, généralisant des résultats de Selberg, Benoist et Oh. / Let G be a real algebraic group of real rank at least 2 and P a parabolic subgroup of G. We prove that any discrete subgroup of G that intersects the unipotent radical of P in a lattice is an arithmetic lattice of G, except maybe when G=SO(2,4n+2) and P is the stabilizer of an isotropic 2-plane. This provide a partial answer to a conjecture of Margulis that was already studied by Hee Oh. We also study the case where G is a product of several rank 1 groups, generalising results of Selberg, Benoist and Oh.