As principais desordens dos membros superiores e cervical (CANS - Complaints of arms, neck and shoulders) podem ser definidas como queixas musculoesqueléticas nas regiões de membro superior, ombro e pescoço não atribuídas a trauma agudo ou a desordens sistêmicas. Essas desordens são comuns entre trabalhadores usuários de computador. O Maastricht Upper Extremity Questionnaire (MUEQ) é uma das poucas ferramentas existentes na literatura para avaliação de risco ergonômico e psicossocial em trabalhadores, além da vantagem de ser específico para usuários de computador, porém não está validado no português-brasileiro. O objetivo deste trabalho foi realizar a adaptação transcultural para o português-brasileiro e validação do MUEQ em trabalhadores de escritório usuários de computador e verificar a prevalência das CANS na amostra recrutada. A tradução e adaptação transcultural seguiram as diretrizes do Consensus-based Standards for the selection of health status Measurement Instruments nos estágios: tradução, síntese, retrotradução, revisão pelo comitê de especialistas e pré-teste. Na etapa do teste da versão pré-final, foram aplicados 55 questionários em trabalhadores usuários de computador, que relataram dificuldades de compreensão abaixo do valor estipulado de 20%, não sendo necessária a reformulação da ferramenta. Para testar a confiabilidade, outros 50 sujeitos preencheram o questionário, em dois momentos, com nível de reprodutibilidade considerado excelente (ICC>0,75). A amostra para a análise da consistência interna e análise fatorial do questionário contou com 386 trabalhadores usuários de computador de mesa entre 18 e 60 anos. Para a consistência interna foram observados valores de de Cronbach maiores que 0,7 para todos os domínios. Na análise fatorial os domínios/subdomínios apresentaram valores de eigenvalue superiores a 1 e os valores de variância explicada acumulada dos fatores de cada domínio variou entre 40% e 60%. A prevalência das CANS nos últimos três meses por pelo menos uma semana foi de 73,32% (IC=0,69-0,77) na amostra total (n=283) e 82% (IC=0,76-0,87) das mulheres e 62% (IC=0,55-0,69) dos homens relataram alguma das CANS. Os domínios foram mantidos iguais à versão original do MUEQ. A queixa musculoesquelética mais observada foi a dor no pescoço (51%). A partir deste trabalho disponibilizou-se um instrumento abrangente e confiável para a avaliação ergonômica e psicossocial relacionado às queixas em cervical e membro superior em trabalhadores usuários de computador brasileiros e foi observada alta prevalência de CANS na população observada. / Complaints of the Arm, Neck and Shoulder (CANS) have a multifactorial etiology, and, therefore, its assessment should take into consideration work-related ergonomic and psychosocial aspects. The Maastricht Upper Extremity Questionnaire (MUEQ) is among the few specific tools available to evaluate the nature and occurrence of CANS in computer office workers. The purpose of the present study was to perform the cross-cultural adaptation of the MUEQ to Brazilian Portuguese and verify the psychometric properties of the MUEQ-Br in Brazilian computer office workers and to assess the prevalence of CANS in a sample of Brazilian computer office workers. The translation and cultural adaptation followed the guidelines of the Consensus-based Standards for the selection of health status Measurement Instruments in six stages: translation, synthesis, back translation, review by the expert committee, pre-test and submission of documents to the committee. In the test of pre-final version, 55 questionnaires were administered to computer workers who reported difficulties in understanding below the stipulated 20%, without the need for redesign of the tool. The pre-final version test counted on the participation of 55 computer office workers. For reproducibility, it was considered a sample of 50 workers who answered the questionnaire twice with a one-week interval. A sample comprised by 386 (37.44 years, Confidence Interval (CI) 95%:36.50-38.38, 216 women and 170 men) workers from the University of São Paulo at Ribeirão Preto campus to validate the structure of the questionnaire, verify internal consistency and CANS prevalence. Intraclass Correlation Coefficient (ICC) was used for the statistical analysis of reproducibility, Cronbachs Alpha for Internal Consistency, and the Principal Component Analysis method for Exploratory Factor Analysis. The psychometric properties of the MUEQ were assessed using exploratory factor analysis, which revealed 14 factors. The calculation of internal consistency, reproducibility and cross validation provided evidence of reliability and lack of redundancy. It was verified ICC values greater than 0.75 and cronbachs alpha greater than 0.7. Factor analysis was conducted for every section of the questionnaire and 14 factors were found, two for each section accounting for approximately 40 to 60% of the variance. The prevalence rate of CANS indicated that 73% (IC=0,69-0,77) of the respondents reported at least one complaint in the arm, neck and/or shoulder in the total sample (n=283), 82% (IC=0,76-0,87) of the women and 62% IC=0,55-0,69) of the men. The highest prevalence rates were found for neck symptoms (51%). The MUEQ-Br demonstrated to be a valid tool for the assessment of risk factors related to pain in the upper extremity among Brazilian computer office workers.

O objetivo deste trabalho foi estudar a expressão protéica de mdm2 e avaliar a sua relação com alguns aspectos anatomopatológicos, visando também identificar fatores prognósticos no que diz respeito à sobrevida livre de recidiva local (SLRL), sobrevida livre de metástase (SLM) e sobrevida global (SG), em pacientes portadores de lipossarcoma primário de extremidades. Vinte e cinco entre 50 pacientes admitidos no Instituto de Ortopedia e Traumatologia do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo – IOT/HC/FMUSP, entre 1968 e 2004, foram eleitos para o estudo. As probabilidades de sobrevida acumuladas foram feitas pela técnica de Kaplan-Meier e as curvas de sobrevida comparadas pelo teste de Log Rank. A validade estatística foi estabelecida para valores de p<0,05. As associações entre os índices positivo ou negativo para o mdm2 com outras variáveis foram feitas utilizando-se o teste exato de Fischer. A expressão imunoistoquímica da proteína mdm2 não foi considerada de valor prognóstico em nenhuma das sobrevidas estudadas (SLRL, SLM ou SG). Os fatores adversos que influenciaram o risco de recidiva local na análise univariada foram: o gênero masculino (p = 0,023), subtipo histológico pleomórfico (p = 0,027) e alto grau histológico (p=0,007). Em relação a SLM a idade inferior a 50 anos (p = 0,040), o gênero masculino (p = 0,040), o subtipo pleomórfico (p < 0,001), o alto grau histológico (p = 0,003) tiveram um pior prognóstico. Os fatores adversos para SG foram: idade inferior a 50 anos (p = 0,040); o gênero masculino (p = 0,040); o subtipo pleomórfico (p < 0,001) e o alto grau histológico (p = 0,003). / The purpose of this was to study the expression by imunohistochemistry of mdm2 and your correlation with anatomopathological selected variables, aiming at identifying prognostic factors concerning to local recurrence free survival (LRFS), metastases free survival (MFS) and overall survival (OS) in patients with liposarcomas primary extremities. This study included 25 patients registred in the Instituto de Ortopedia e Traumatologia do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo - Brazil, from 1968 to 2004. The accumulated survival probabilities were calculated by Kaplan-Meier method and survival curves were compared using the logrank test. Statistical significance was defined as a p value less than 0,05. Associations between expression of mdm2 and other variables were analyzed using Fischer’s exact test. The expression by imunohistochemistry of mdm2 was not significant factor for LRFS, MFS or OS. The adverse factors for LRFS in univariate analysis were male gender (p = 0,023), pleomorfic histologic subtypes (p = 0,027) and high grade tumor (p = 0,007). For MFS age < 50 years (p = 0,040), male gender (p = 0,040), pleomorfic histologic subtypes (p < 0,001) and high grade tumor (p = 0,003) had worse prognostic. Negative prognostic factors for OS were age < 50 years (p = 0,040), male gender (p = 0,040), pleomorfic histologic subtypes (p < 0,001) and high grade tumor (p = 0,003).

Patient reported outcome (PRO) measurement of disability is integral to a patient-centered approach to health care and gauging the biopsychosocial impact of health conditions from the patient's perspective. This thesis investigates disability after proximal humerus, elbow and distal radius fractures; conditions that constitute a major burden in musculoskeletal health care and a substantial impact on health-related quality of life (HrQoL). Disability is defined by the World Health Organisation (WHO) International Classification of Disability, Functioning and Health (ICF) as ‘a multi-dimensional construct involving a dynamic interaction between impairment, activity limitations and participation restrictions, that are influenced by contextual factors'. This international, consensus-based framework acts as a guide for the application of outcome measures in performing scientific research. The WHO ICF also considers other patient perspectives on health and health care systems, including patient experience and patient activation within the contextual factors component. Patient experience encompasses aspects such as satisfaction, expectation management and confidence with care, and is measured using a variety of scales and questionnaires. Patient activation relates to 'the knowledge, skills and confidence a person has in managing their own health and health care'. This concept is quantified using patient activation measures (PAMs). The overarching goal of this thesis is to identify the most influential factors predicting disability after proximal humerus, elbow and distal radius fractures. This work also aimed to define the relationship between disability, experience and activation to inform the development of a patient-centred approach to managing these challenging injuries. The first systematic review highlights the dominance of psychosocial factors in influencing disability associated with a range of upper extremity conditions. Few studies have assessed this relationship in specific trauma populations. The second review underlines the paucity of upper extremity PRO measures incorporating fracture populations in their original development. It also reports the highly variable quality of initial studies introducing these measures. The final review demonstrates the superior measurement properties of computer adaptive tests (CATs), a contemporary form of PRO measurement, over fixed-scale instruments. Few studies apply CATs in trauma and few have been performed outside the U.S. These reviews collectively informed the selection of PRO measures for the experimental studies in this thesis. Firstly, a pilot study establishes a methodology for addressing the key objectives and the feasibility of using a web-based platform for measuring patient outcomes. Strong correlation between PROMIS Physical function CAT, a computer adaptive measure of physical function, and the Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH), a region-specific, fixed scale is observed. The core experiment (n=734) expands upon this work and demonstrates correlations between a range of generic and region-specific measures in an upper extremity trauma population. Disability is shown to correlate with satisfaction, and the strength of this correlation increases over time. Applying PRO measures of disability in populations with shoulder, elbow and wrist fractures show that self-efficacy (i.e. coping ability) within 6 weeks of injury was the strongest predictor of medium-term disability at 6-9 months. In proximal humerus and elbow fractures, kinesiophobia (i.e. fear of movement) within a week of injury was also a strong predictor of disability. The final study concludes that greater patient activation is associated with greater health-related and experiential outcomes. However, psychosocial factors including self-efficacy, superseded activation in predicting disability and satisfaction. This thesis contributes evidence for musculoskeletal health care professionals (HCPs) to consider specific psychosocial factors, such as coping abilities, and patient activation early in the recovery process to improve disability following these injuries.

As principais desordens dos membros superiores e cervical (CANS - Complaints of arms, neck and shoulders) podem ser definidas como queixas musculoesqueléticas nas regiões de membro superior, ombro e pescoço não atribuídas a trauma agudo ou a desordens sistêmicas. Essas desordens são comuns entre trabalhadores usuários de computador. O Maastricht Upper Extremity Questionnaire (MUEQ) é uma das poucas ferramentas existentes na literatura para avaliação de risco ergonômico e psicossocial em trabalhadores, além da vantagem de ser específico para usuários de computador, porém não está validado no português-brasileiro. O objetivo deste trabalho foi realizar a adaptação transcultural para o português-brasileiro e validação do MUEQ em trabalhadores de escritório usuários de computador e verificar a prevalência das CANS na amostra recrutada. A tradução e adaptação transcultural seguiram as diretrizes do Consensus-based Standards for the selection of health status Measurement Instruments nos estágios: tradução, síntese, retrotradução, revisão pelo comitê de especialistas e pré-teste. Na etapa do teste da versão pré-final, foram aplicados 55 questionários em trabalhadores usuários de computador, que relataram dificuldades de compreensão abaixo do valor estipulado de 20%, não sendo necessária a reformulação da ferramenta. Para testar a confiabilidade, outros 50 sujeitos preencheram o questionário, em dois momentos, com nível de reprodutibilidade considerado excelente (ICC>0,75). A amostra para a análise da consistência interna e análise fatorial do questionário contou com 386 trabalhadores usuários de computador de mesa entre 18 e 60 anos. Para a consistência interna foram observados valores de de Cronbach maiores que 0,7 para todos os domínios. Na análise fatorial os domínios/subdomínios apresentaram valores de eigenvalue superiores a 1 e os valores de variância explicada acumulada dos fatores de cada domínio variou entre 40% e 60%. A prevalência das CANS nos últimos três meses por pelo menos uma semana foi de 73,32% (IC=0,69-0,77) na amostra total (n=283) e 82% (IC=0,76-0,87) das mulheres e 62% (IC=0,55-0,69) dos homens relataram alguma das CANS. Os domínios foram mantidos iguais à versão original do MUEQ. A queixa musculoesquelética mais observada foi a dor no pescoço (51%). A partir deste trabalho disponibilizou-se um instrumento abrangente e confiável para a avaliação ergonômica e psicossocial relacionado às queixas em cervical e membro superior em trabalhadores usuários de computador brasileiros e foi observada alta prevalência de CANS na população observada. / Complaints of the Arm, Neck and Shoulder (CANS) have a multifactorial etiology, and, therefore, its assessment should take into consideration work-related ergonomic and psychosocial aspects. The Maastricht Upper Extremity Questionnaire (MUEQ) is among the few specific tools available to evaluate the nature and occurrence of CANS in computer office workers. The purpose of the present study was to perform the cross-cultural adaptation of the MUEQ to Brazilian Portuguese and verify the psychometric properties of the MUEQ-Br in Brazilian computer office workers and to assess the prevalence of CANS in a sample of Brazilian computer office workers. The translation and cultural adaptation followed the guidelines of the Consensus-based Standards for the selection of health status Measurement Instruments in six stages: translation, synthesis, back translation, review by the expert committee, pre-test and submission of documents to the committee. In the test of pre-final version, 55 questionnaires were administered to computer workers who reported difficulties in understanding below the stipulated 20%, without the need for redesign of the tool. The pre-final version test counted on the participation of 55 computer office workers. For reproducibility, it was considered a sample of 50 workers who answered the questionnaire twice with a one-week interval. A sample comprised by 386 (37.44 years, Confidence Interval (CI) 95%:36.50-38.38, 216 women and 170 men) workers from the University of São Paulo at Ribeirão Preto campus to validate the structure of the questionnaire, verify internal consistency and CANS prevalence. Intraclass Correlation Coefficient (ICC) was used for the statistical analysis of reproducibility, Cronbachs Alpha for Internal Consistency, and the Principal Component Analysis method for Exploratory Factor Analysis. The psychometric properties of the MUEQ were assessed using exploratory factor analysis, which revealed 14 factors. The calculation of internal consistency, reproducibility and cross validation provided evidence of reliability and lack of redundancy. It was verified ICC values greater than 0.75 and cronbachs alpha greater than 0.7. Factor analysis was conducted for every section of the questionnaire and 14 factors were found, two for each section accounting for approximately 40 to 60% of the variance. The prevalence rate of CANS indicated that 73% (IC=0,69-0,77) of the respondents reported at least one complaint in the arm, neck and/or shoulder in the total sample (n=283), 82% (IC=0,76-0,87) of the women and 62% IC=0,55-0,69) of the men. The highest prevalence rates were found for neck symptoms (51%). The MUEQ-Br demonstrated to be a valid tool for the assessment of risk factors related to pain in the upper extremity among Brazilian computer office workers.

O objetivo deste trabalho foi estudar a expressão protéica de mdm2 e avaliar a sua relação com alguns aspectos anatomopatológicos, visando também identificar fatores prognósticos no que diz respeito à sobrevida livre de recidiva local (SLRL), sobrevida livre de metástase (SLM) e sobrevida global (SG), em pacientes portadores de lipossarcoma primário de extremidades. Vinte e cinco entre 50 pacientes admitidos no Instituto de Ortopedia e Traumatologia do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo – IOT/HC/FMUSP, entre 1968 e 2004, foram eleitos para o estudo. As probabilidades de sobrevida acumuladas foram feitas pela técnica de Kaplan-Meier e as curvas de sobrevida comparadas pelo teste de Log Rank. A validade estatística foi estabelecida para valores de p<0,05. As associações entre os índices positivo ou negativo para o mdm2 com outras variáveis foram feitas utilizando-se o teste exato de Fischer. A expressão imunoistoquímica da proteína mdm2 não foi considerada de valor prognóstico em nenhuma das sobrevidas estudadas (SLRL, SLM ou SG). Os fatores adversos que influenciaram o risco de recidiva local na análise univariada foram: o gênero masculino (p = 0,023), subtipo histológico pleomórfico (p = 0,027) e alto grau histológico (p=0,007). Em relação a SLM a idade inferior a 50 anos (p = 0,040), o gênero masculino (p = 0,040), o subtipo pleomórfico (p < 0,001), o alto grau histológico (p = 0,003) tiveram um pior prognóstico. Os fatores adversos para SG foram: idade inferior a 50 anos (p = 0,040); o gênero masculino (p = 0,040); o subtipo pleomórfico (p < 0,001) e o alto grau histológico (p = 0,003). / The purpose of this was to study the expression by imunohistochemistry of mdm2 and your correlation with anatomopathological selected variables, aiming at identifying prognostic factors concerning to local recurrence free survival (LRFS), metastases free survival (MFS) and overall survival (OS) in patients with liposarcomas primary extremities. This study included 25 patients registred in the Instituto de Ortopedia e Traumatologia do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo - Brazil, from 1968 to 2004. The accumulated survival probabilities were calculated by Kaplan-Meier method and survival curves were compared using the logrank test. Statistical significance was defined as a p value less than 0,05. Associations between expression of mdm2 and other variables were analyzed using Fischer’s exact test. The expression by imunohistochemistry of mdm2 was not significant factor for LRFS, MFS or OS. The adverse factors for LRFS in univariate analysis were male gender (p = 0,023), pleomorfic histologic subtypes (p = 0,027) and high grade tumor (p = 0,007). For MFS age < 50 years (p = 0,040), male gender (p = 0,040), pleomorfic histologic subtypes (p < 0,001) and high grade tumor (p = 0,003) had worse prognostic. Negative prognostic factors for OS were age < 50 years (p = 0,040), male gender (p = 0,040), pleomorfic histologic subtypes (p < 0,001) and high grade tumor (p = 0,003).

L’objectif principal de cette thèse est de s’intéresser aux fortes pluies dans les Monts Métallifères (OM) et les Vosges (VG) en Europe centrale. La méthode Weather Extremity Index a été appliquée sur les données de précipitation journalière de 167 stations dans les OM et 168 stations dans les VG et a permis de sélectionner les 54 plus forts évenements des précipitations extrêmes (EPEs) dans OM et VG. Plusieurs aspects des EPEs ont été examinés. Les résultats ont montré que les EPEs sont le plus souvent de courte durée (1—2 jours) dans les deux régions. Ils affectent une plus grande partie des OM que des VG. Les EPEs dans les VG apparaissent majoritairement lors de la situation synoptique d’un front froid ondulant ; dans les OM lors des cyclones générés par une goutte d’air froid isolé et dont le trajet est souvent qualifié de « Vb » (c.a.d. allant de la Méditerranée vers le nord-est). Toutefois deux des dix plus forts EPEs des VG sont apparus lors de situations de cyclones Vb. / The thesis focuses on extreme precipitation in the Ore Mountains (OM) and the Vosges Mountains (VG) in Central Europe. The Weather Extremity Index (WEI) was employed on daily precipitation totals from 167 stations in OM and 168 stations in VG. The WEI enabled to select the 54 strongest extreme precipitation events (EPEs) in OM and VG. Many characteristics of the EPEs were investigated in the thesis. The results showed that the EPEs lasted mostly 1—2 days in both regions, whereas affected a larger part of OM as compared to VG. Stationary fronts occurred most frequently during EPEs in VG, while lows in OM. Lows in OM during EPEs often originated from cold air cut-off and most of them had Vb track from Mediterranean towards the northeast. Even during two of the ten strongest EPEs in VG, the extreme precipitation was related to Vb lows, this time strongly deflected westwards.

It is proven that locations of internal body joints are sufficient visual cues to characterize human motion. In this dissertation I propose that locations of human extremities including heads, hands and feet provide powerful approximation to internal body motion. I propose detection of precise extremities from contours obtained from image segmentation or contour tracking. Junctions of medial axis of contours are selected as stars. Contour points with a local maximum distance to various stars are chosen as candidate extremities. All the candidates are filtered by cues including proximity to other candidates, visibility to stars and robustness to noise smoothing parameters. I present my applications of using precise extremities for fast human action detection and recognition. Environment specific features are built from precise extremities and feed into a block based Hidden Markov Model to decode the fence climbing action from continuous videos. Precise extremities are grouped into stable contacts if the same extremity does not move for a certain duration. Such stable contacts are utilized to decompose a long continuous video into shorter pieces. Each piece is associated with certain motion features to form primitive motion units. In this way the sequence is abstracted into more meaningful segments and a searching strategy is used to detect the fence climbing action. Moreover, I propose the histogram of extremities as a general posture descriptor. It is tested in a Hidden Markov Model based framework for action recognition. I further propose detection of probable extremities from raw images without any segmentation. Modeling the extremity as an image patch instead of a single point on the contour helps overcome the segmentation difficulty and increase the detection robustness. I represent the extremity patches with Histograms of Oriented Gradients. The detection is achieved by window based image scanning. In order to reduce computation load, I adopt the integral histograms technique without sacrificing accuracy. The result is a probability map where each pixel denotes probability of the patch forming the specific class of extremities. With a probable extremity map, I propose the histogram of probable extremities as another general posture descriptor. It is tested on several data sets and the results are compared with that of precise extremities to show the superiority of probable extremities. / text

Lower extremity injuries are the most common sports related injury. Many steps have been taken to attempt to identify individuals who might be at a higher risk for sustaining a lower extremity injury. Resource and time intensive screening techniques have been used previously to attempt to identify such individuals. However these techniques have focused heavily on postural control and landing mechanics in athletes, no psychological measure has been used to identify individuals who might be at a higher risk of lower extremity injury. Self-efficacy of balance can be defined as how capable an individual feels he or she can balance in different scenarios. Research in the balance deficient population (elderly, post-stroke, knee osteoarthritis) has revealed that selfefficacy of balance is a quantifiable psychological component of balance related behavior. As previously stated, current screening techniques for lower extremity injuries do not incorporate psychological measures. Research suggests that psychological indicators of balance confidence are important to measure in conjunction with balance test performance to establish the relationship between the two constructs. Assessment of these factors is necessary to examine how psychological measures affect performance on tests used in clinical balance assessments. The objective of this dissertation was to develop the Self-Efficacy of Balance Scale (SEBS), a psychometrically sound self-efficacy of balance instrument for use in the young, active population. The relationship between selfefficacy of balance and self-reported measures of lower extremity function, and clinical and laboratory measures of balance were also examined in the young, active population. It was hypothesized that a valid, reliable, responsive tool could be created to accurately and precisely measure self-efficacy of balance in a young, active population. It addition, it was hypothesized that high levels of selfefficacy of balance would have a significant, positive relationship with selfreported measure of lower extremity function, and clinical and laboratory measure of balance. Results from the three studies brought about several interesting observations. Studies one, two, and three demonstrated evidence of a psychometrically sound instrument. This indicates that the SEBS is a valid, reliable, responsive self-efficacy of balance instrument when evaluating young, active individuals. Study three demonstrated the relationships between selfefficacy of balance and self-reported measures of function, and objective measures of balance. These relationships revealed that while lower extremity function and some measures of balance influence scores of the SEBS, they do not account for all of the variability of the SEBS. This finding further supports the claim that balance behavior is changing as function and postural control change. Therefore, future research should include investigation regarding the utility of the SEBS, as well as longitudinal studies to establish effectiveness of identifying individuals at a higher risk of sustaining a lower extremity injury.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

Four studies investigated the effects of attitude extremity and political ideology on the degree and direction of changes in issue attitudes following the presentation of mixed evidence. Based upon previous work, it was predicted that those holding relatively more extreme attitudes would resist changing those views when presented with a mixture of supporting and opposing statements and would potentially adopt more extreme evaluative positions – a phenomenon known as attitude polarization (Lord, Ross, & Lepper, 1979). Evaluative entrenchment or intensification was also expected among more politically conservative participants, based upon prior work describing cognitive rigidity and resistance to change as more characteristic of the political right than left (e.g., Jost, Glaser, Kruglanski, & Sulloway, 2003). An interaction of attitude extremity and political ideology was also hypothesized, such that liberal individuals with moderate attitudes were expected to demonstrate the least propensity to polarize. Participants’ attitudes regarding abortion rights (Study 1), gun control (Study 2), tax increases (Study 3), and environmental preservation (Study 4) were assessed before and after reading statements that both opposed and supported the issue. Political ideology was also assessed, along with several individual difference factors. Across all four studies, attitude extremity significantly predicted evaluative change, although the pattern of that effect varied. Political ideology did not emerge consistently as a predictor of attitude change; however, significant interactive effects of extremity and ideology were found. In addition, several individual difference factors (i.e., gender, need for cognition, issue importance) were found to moderate the effects of the primary predictors on attitude change, and some divergent result patterns were found when comparing data from a college and non-college sample in Study 4. Taken together, these studies provide evidence that attitude extremity and political ideology influence the degree and direction of evaluative change following the presentation of mixed evidence. In addition, they identify other factors at work in effecting change versus resistance, thereby highlighting the multi-faceted and complex nature of persuasion in a political context.