Title from PDF of title page (University of Missouri--Columbia, viewed on Feb 17, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Dissertation advisor: Dr. Michael Mobley. Vita. Includes bibliographical references.

abstract: Mediation analysis is a statistical approach that examines the effect of a treatment (e.g., prevention program) on an outcome (e.g., substance use) achieved by targeting and changing one or more intervening variables (e.g., peer drug use norms). The increased use of prevention intervention programs with outcomes measured at multiple time points following the intervention requires multilevel modeling techniques to account for clustering in the data. Estimating multilevel mediation models, in which all the variables are measured at individual level (Level 1), poses several challenges to researchers. The first challenge is to conceptualize a multilevel mediation model by clarifying the underlying statistical assumptions and implications of those assumptions on cluster-level (Level-2) covariance structure. A second challenge is that variables measured at Level 1 potentially contain both between- and within-cluster variation making interpretation of multilevel analysis difficult. As a result, multilevel mediation analyses may yield coefficient estimates that are composites of coefficient estimates at different levels if proper centering is not used. This dissertation addresses these two challenges. Study 1 discusses the concept of a correctly specified multilevel mediation model by examining the underlying statistical assumptions and implication of those assumptions on Level-2 covariance structure. Further, Study 1 presents analytical results showing algebraic relationships between the population parameters in a correctly specified multilevel mediation model. Study 2 extends previous work on centering in multilevel mediation analysis. First, different centering methods in multilevel analysis including centering within cluster with the cluster mean as a Level-2 predictor of intercept (CWC2) are discussed. Next, application of the CWC2 strategy to accommodate multilevel mediation models is explained. It is shown that the CWC2 centering strategy separates the between- and within-cluster mediated effects. Next, Study 2 discusses assumptions underlying a correctly specified CWC2 multilevel mediation model and defines between- and within-cluster mediated effects. In addition, analytical results for the algebraic relationships between the population parameters in a CWC2 multilevel mediation model are presented. Finally, Study 2 shows results of a simulation study conducted to verify derived algebraic relationships empirically. / Dissertation/Thesis / Ph.D. Psychology 2010

Orientador: Júlia Ziviani Vitiello / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Artes / Made available in DSpace on 2018-08-17T11:20:22Z (GMT). No. of bitstreams: 1 Pees_AdrianaAlmeida_D.pdf: 45750189 bytes, checksum: a1f9701451b5c8aef61be6cb017ff685 (MD5) Previous issue date: 2010 / Resumo: Esta pesquisa busca através dos princípios de movimento do método Body-Mind Centering® (BMC) ? desenvolvido por Bonnie Bainbridge Cohen ? estudar o Sistema Vestibular e suas relações com o equilíbrio do corpo. Investiga suas possíveis contribuições quanto ao desenvolvimento motor e suas implicações qualitativas nos gestos e nas ações para a atuação e criação nas artes cênicas. Desde que o equilíbrio corporal deve-se a interação de três sistemas: somatosensorial, visual e vestibular. O método Body-Mind Centering® apresentase relevante neste estudo, pois seus princípios proporcionam uma vivência anatômica de diferentes sistemas corporais, favorecendo o reconhecimento da atuação do sistema vestibular no movimento. Isso conduz à compreensão de como abrangemos inteligentemente os sentidos no corpo, e como estes se relacionam com a percepção e o desenvolvimento do movimento. Almeja-se que esta pesquisa possa elucidar de que maneira o BMC pode interferir no aprendizado de como as ações se codificam possibilitando que se compreenda também que novas maneiras de co-emergir nos movimentos habilita e sustenta o processo criativo, uma vez que na dança, o artista conta com o próprio corpo para desenvolver seu trabalho de interpretação e criação. Esse processo de criação deve contar, por parte do artista, com uma atitude baseada na percepção do equilíbrio do seu corpo, nas suas escolhas e nas qualidades inerentes da reestruturação equilíbrio/desequilíbrio no movimento e no desenho coreográfico. A aplicação desta pesquisa foi realizada no entrelaçamento de três vias, as quais consideramos essenciais: laboratórios práticos (vivência específica da teoria por meio do Método BMC), de criação (desenvolvimento de uma coreografia) e pelo estudo da obra do pintor Paul Klee, que contribuiu como alicerce poético/imagético ao processo coreográfico. / Abstract: This research aims, through the movement principles of the Body-Mind Centering® (BMC) method developed by Bonnie Bainbridge Cohen, at studying the Vestibular System and its connections with body balance. It researches its possible contributions regarding the motor development and its qualitative implications in gestures and actions towards acting and creation in performing arts. Since body balance is due to the interaction of three systems: somatosensory, visual and vestibular, the Body-Mind Centering® method is realized as relevant in this study, as its principles provide an anatomic experience of different body systems, favoring the recognition of the vestibular system action in motion. This leads to understanding how we wisely cover the senses in the body, and how these senses relate to perception and motion development. This research is intended to be able to elucidate how BMC can interfere in learning the way the actions are coded allowing one to also realize that new ways to co-emerge in the movements enables and supports the creative system, since in dance, the artist counts on the proper body to develop his or her interpretation and creation work. This creation process must count, by the artist, on an attitude based on his/her body's balance perception, on his/her choices and on the inherent qualities of balance/unbalance restructuring in motion and choreographic design. The application of this research has been achieved in the three-way interlacement, which we consider essential: practical laboratories (specific experience of theory by means of BMC Method), of creation (development of a choreography) and by studying painter Paul Klee's work, which has contributed as a poetic/imagetic foundation to the choreographic process. / Doutorado / Artes Cenicas / Doutor em Artes

While a significant amount of research illustrates the positive effects of therapists’ use of mindfulness, few studies have addressed whether therapists’ mindfulness actually improves psychotherapy outcomes. Additionally, no existing research has examined whether therapists’ use of a mindfulness exercise immediately before meeting with a client could also have a positive impact on the following session. The purpose of this study was to test whether engaging in a centering exercise 5-10 minutes before a session could have a positive impact on therapy, in particular on the therapists’ ability to remain present in session. Results indicated that the trainee therapists did not report changes in mindfulness after the brief mindfulness training program. Results also indicated that completing the centering exercise before a session did not appear to impact client ratings of therapeutic presence and session outcomes. The results suggest that more intensive training in mindfulness may be necessary to impact psychotherapy outcomes.

The self-centering energy dissipative (SCED) brace is an innovative cross-bracing system that eliminates residual building deformations after seismic events and prevents the progressive drifting that other inelastic systems are prone to experience under long-duration ground motions. This research improves upon the design and use of SCED braces through three large-scale experimental studies and an associated numerical building model study. The first experimental study increased the strength capacity of SCED braces and refined the design procedure through the design and testing of a new high-capacity full-scale SCED brace. This brace exhibited full self-centering behaviour and did not show significant degradation of response after multiple earthquake loadings. The second experimental study extended the elongation capacity of SCED braces through the design and testing of a new telescoping SCED (T-SCED) brace that provided self-centering behaviour over a deformation range that was two times the range that was achieved by the original SCED bracing system. It exhibited full self-centering in a single storey full-scale frame that was laterally deformed to 4% of its storey height. The third experimental study confirmed the dynamic behaviour of a multi-storey SCED-frame in different seismic environments and confirmed the ability of computer models of differing complexity to accurately predict the seismic response. To achieve these goals, a three-storey SCED-braced frame was designed, constructed, and tested on a shake table. Lastly, a numerical six-storey SCED-braced building model was constructed. This model used realistic brace properties that were determined using a new software tool that simulates the full detailed mechanics of SCED and T-SCED braces. The building model showed that initial SCED brace stiffness does not have a significant effect on SCED frame behaviour, that T-SCEDs generally perform better than traditional SCEDs, and that the addition of viscous dampers in parallel with SCED braces can significantly reduce drifts and accelerations while only causing a small increase in the base shear.

Substructure hybrid simulation has been actively investigated in recent years. The simulation method allows for the assessment of seismic performance of structures by representing critical components with physical specimens and the rest of the structure with numerical models. In this study the system level performance of a six-storey structure with self-centering energy dissipative (SCED) braces was validated through pseudo dynamic (PsD) hybrid simulation. Fragility curves are derived for the SCED system. The study presents the configuration of the hybrid simulation and discusses some of the practical intricacies in performing PsD hybrid simulations. In addition the study addresses some of the challenges associated with the substructuring process during a hybrid simulation. Two techniques, extensive analytical study and model updation, are discussed to improve the response from the hybrid simulation accounting for the variation in global response of a structural system depending on which structural element was represented as a physical specimen.

The self-centering energy dissipative (SCED) brace is an innovative cross-bracing system that eliminates residual building deformations after seismic events and prevents the progressive drifting that other inelastic systems are prone to experience under long-duration ground motions. This research improves upon the design and use of SCED braces through three large-scale experimental studies and an associated numerical building model study. The first experimental study increased the strength capacity of SCED braces and refined the design procedure through the design and testing of a new high-capacity full-scale SCED brace. This brace exhibited full self-centering behaviour and did not show significant degradation of response after multiple earthquake loadings. The second experimental study extended the elongation capacity of SCED braces through the design and testing of a new telescoping SCED (T-SCED) brace that provided self-centering behaviour over a deformation range that was two times the range that was achieved by the original SCED bracing system. It exhibited full self-centering in a single storey full-scale frame that was laterally deformed to 4% of its storey height. The third experimental study confirmed the dynamic behaviour of a multi-storey SCED-frame in different seismic environments and confirmed the ability of computer models of differing complexity to accurately predict the seismic response. To achieve these goals, a three-storey SCED-braced frame was designed, constructed, and tested on a shake table. Lastly, a numerical six-storey SCED-braced building model was constructed. This model used realistic brace properties that were determined using a new software tool that simulates the full detailed mechanics of SCED and T-SCED braces. The building model showed that initial SCED brace stiffness does not have a significant effect on SCED frame behaviour, that T-SCEDs generally perform better than traditional SCEDs, and that the addition of viscous dampers in parallel with SCED braces can significantly reduce drifts and accelerations while only causing a small increase in the base shear.

Substructure hybrid simulation has been actively investigated in recent years. The simulation method allows for the assessment of seismic performance of structures by representing critical components with physical specimens and the rest of the structure with numerical models. In this study the system level performance of a six-storey structure with self-centering energy dissipative (SCED) braces was validated through pseudo dynamic (PsD) hybrid simulation. Fragility curves are derived for the SCED system. The study presents the configuration of the hybrid simulation and discusses some of the practical intricacies in performing PsD hybrid simulations. In addition the study addresses some of the challenges associated with the substructuring process during a hybrid simulation. Two techniques, extensive analytical study and model updation, are discussed to improve the response from the hybrid simulation accounting for the variation in global response of a structural system depending on which structural element was represented as a physical specimen.

The structural damage after the Christchurch earthquake (2011) led to extensively damaged facilities that did not collapse but did require demolition, representing more than 70% of the building stock in the central business district. These severe economic losses that result from conventional seismic design clearly show the importance of moving towards resilience-based design approaches of structures. For instance, special reinforced masonry shear walls (SRMWs), which are fixed-base walls, are typically designed to dissipate energy through the yielding of bonded reinforcement while special detailing is maintained to fulfill ductility requirements. This comes at the expense of accepting residual drifts and permanent damage in potential plastic hinge zones. This design process hinders the overall resilience of such walls because of the costs and time associated with the loss of operation and service shutdown. In controlled rocking systems, an elastic gap opening mechanism (i.e., rocking joint) replaces the typical yielding of the main reinforcement in conventional fixed-base walls, hence reducing wall lateral stiffness without excessive yielding damage. Consequently, controlled rocking wall systems with limited damage and self-centering behavior under the control of unbonded post-tensioning (PT) are considered favorable for modern resilient cities because of the costs associated with service shutdown (i.e., for structural repairs or replacement) are minimized. However, the difficulty of PT implementation during construction is challenging in practical masonry applications. In addition, PT losses due to PT yielding and early strength degradation of masonry reduce the self-centering ability of controlled rocking masonry walls with unbonded post-tensioning (PT-CRMWs). Such challenges demonstrate the importance of considering an alternative source of self-centering. In this regard, the current study initially evaluates the seismic performance of PT-CRMWs compared to SRMWs. Next, a new controlled rocking system for masonry walls is proposed, namely Energy Dissipation-Controlled Rocking Masonry Walls (ED-CRMWs), which are designed to self-center through vertical gravity loads only, without the use of PT tendons. To control the rocking response, supplemental energy dissipation (ED) devices are included. This proposed system is evaluated experimentally in two phases. In Phase I of the experimental program, the focus is to ensure that the intended behavior of ED-CRMWs is achieved. This is followed by design guidance, validated through collapse risk analysis of a series of 20 ED-CRMW archetypes. Finally, Phase II of the experimental program evaluates a more resilient ED-CRMW is evaluated, which incorporates a readily replaceable externally mounted flexural arm ED device. Design guidance is also provided for ED-CRMWs incorporating such devices. / Thesis / Doctor of Philosophy (PhD)

M.A.Sc. Thesis / Most conventional seismic design intends for key structural members to yield in order to limit seismic forces, leading to structural damage after a major earthquake. To minimize this structural damage, self-centering systems are being developed. But how to estimate the peak seismic displacement of a self-centering system remains a problem for practical design. This thesis addresses this need by presenting a parametric study on the seismic displacement demands of single-degree-of-freedom (SDOF) systems with flag-shaped hysteresis considering 13,440,000 nonlinear time history analyses. Ground motion records that represent seismic hazards in active seismic regions with stiff soil and rock site conditions are used. The influences of the four independent parameters that define a flag-shaped hysteresis are presented in terms of median displacement ratios, facilitating the design-level estimation of nonlinear displacement demands on self-centering systems from the spectra displacements of elastic systems. The influence of initial period on self-centering systems is similar to its influence on traditional systems with elastoplastic hysteresis, but a much lower linear limit can be adopted for self-centering systems while achieving acceptable peak displacements. Supplemental energy dissipation suppresses the peak displacement but additional energy dissipation becomes less effective as more is added. The effect of nonlinear stiffness is small as long as it is positive and close to zero, but a negative nonlinear stiffness can lead to unstable response. Self-centering systems located on rock sites usually have smaller displacement demands than those on stiff soil sites. When the damping ratio is increased or decreased, the displacement ratios do not necessarily decrease or increase consistently. A tangent stiffness proportional damping model is considered, leading to a significant increase in displacement demands but similar overall trends. Based on the observations, regression analysis is used to develop a simplified equation that approximates the median inelastic displacement ratios of self-centering systems for design. / Thesis / Master of Applied Science (MASc)