Determinação da resistência flexural de cimentos resinosos comerciais, com variação do sistema de ativação e tempo de armazenamento pós-ativação

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências da Saúde. Programa de Pós-Graduação em Odontologia.Este estudo investigou a resistência flexural de amostras confeccionadas com os cimentos resinosos duais Enforce, RelyX CRA e Variolink II submetidas à dupla ativação ou apenas à ativação química, aos trinta minutos e vinte e quatro horas após o início da polimerização. O cimento Enforce apresentou os valores mais altos de resistência flexural, independentemente do tipo de ativação e do tempo de armazenamento. No período de 30 minutos de armazenamento, não foram observadas significâncias estatísticas entre os materiais e a dupla ativação. Já, na polimerização química, o Enforce foi superior aos outros materiais testados neste mesmo tipo de polimerização. No período de 24 horas de armazenamento, não houve significâncias estatísticas na interação materiais x tipos de ativação

Clinical Reasoning in the Real World Is Mediated by Bounded Rationality: Implications for Diagnostic Clinical Practice Guidelines

Background: Little is known about the reasoning mechanisms used by physicians in decision-making and how this compares to diagnostic clinical practice guidelines. We explored the clinical reasoning process in a real life environment. Method: This is a qualitative study evaluating transcriptions of sixteen physicians' reasoning during appointments with patients, clinical discussions between specialists, and personal interviews with physicians affiliated to a hospital in Brazil. Results: Four main themes were identified: simple and robust heuristics, extensive use of social environment rationality, attempts to prove diagnostic and therapeutic hypothesis while refuting potential contradictions using positive test strategy, and reaching the saturation point. Physicians constantly attempted to prove their initial hypothesis while trying to refute any contradictions. While social environment rationality was the main factor in the determination of all steps of the clinical reasoning process, factors such as referral letters and number of contradictions associated with the initial hypothesis had influence on physicians' confidence and determination of the threshold to reach a final decision. Discussion: Physicians rely on simple heuristics associated with environmental factors. This model allows for robustness, simplicity, and cognitive energy saving. Since this model does not fit into current diagnostic clinical practice guidelines, we make some propositions to help its integration. Copyright: © 2010 Bonilauri Ferreira et al

Qualitative Analysis of the Interdisciplinary Interaction between Data Analysis Specialists and Novice Clinical Researchers

Background: The inherent complexity of statistical methods and clinical phenomena compel researchers with diverse domains of expertise to work in interdisciplinary teams, where none of them have a complete knowledge in their counterpart's field. As a result, knowledge exchange may often be characterized by miscommunication leading to misinterpretation, ultimately resulting in errors in research and even clinical practice. Though communication has a central role in interdisciplinary collaboration and since miscommunication can have a negative impact on research processes, to the best of our knowledge, no study has yet explored how data analysis specialists and clinical researchers communicate over time. Methods/Principal Findings: We conducted qualitative analysis of encounters between clinical researchers and data analysis specialists (epidemiologist, clinical epidemiologist, and data mining specialist). These encounters were recorded and systematically analyzed using a grounded theory methodology for extraction of emerging themes, followed by data triangulation and analysis of negative cases for validation. A policy analysis was then performed using a system dynamics methodology looking for potential interventions to improve this process. Four major emerging themes were found. Definitions using lay language were frequently employed as a way to bridge the language gap between the specialties. Thought experiments presented a series of ""what if'' situations that helped clarify how the method or information from the other field would behave, if exposed to alternative situations, ultimately aiding in explaining their main objective. Metaphors and analogies were used to translate concepts across fields, from the unfamiliar to the familiar. Prolepsis was used to anticipate study outcomes, thus helping specialists understand the current context based on an understanding of their final goal. Conclusion/Significance: The communication between clinical researchers and data analysis specialists presents multiple challenges that can lead to errors

Selection Mechanisms Underlying High Impact Biomedical Research - A Qualitative Analysis and Causal Model

BACKGROUND: Although scientific innovation has been a long-standing topic of interest for historians, philosophers and cognitive scientists, few studies in biomedical research have examined from researchers' perspectives how high impact publications are developed and why they are consistently produced by a small group of researchers. Our objective was therefore to interview a group of researchers with a track record of high impact publications to explore what mechanism they believe contribute to the generation of high impact publications. METHODOLOGY/PRINCIPAL FINDINGS: Researchers were located in universities all over the globe and interviews were conducted by phone. All interviews were transcribed using standard qualitative methods. A Grounded Theory approach was used to code each transcript, later aggregating concept and categories into overarching explanation model. The model was then translated into a System Dynamics mathematical model to represent its structure and behavior. Five emerging themes were found in our study. First, researchers used heuristics or rules of thumb that came naturally to them. Second, these heuristics were reinforced by positive feedback from their peers and mentors. Third, good communication skills allowed researchers to provide feedback to their peers, thus closing a positive feedback loop. Fourth, researchers exhibited a number of psychological attributes such as curiosity or open-mindedness that constantly motivated them, even when faced with discouraging situations. Fifth, the system is dominated by randomness and serendipity and is far from a linear and predictable environment. Some researchers, however, took advantage of this randomness by incorporating mechanisms that would allow them to benefit from random findings. The aggregation of these themes into a policy model represented the overall expected behavior of publications and their impact achieved by high impact researchers. CONCLUSIONS: The proposed selection mechanism provides insights that can be translated into research coaching programs as well as research policy models to optimize the introduction of high impact research at a broad scale among institutional and governmental agencies

Intraobserver and interobserver reproducibility of the old and new classifications of toracolombar fractures

ABSTRACT Objective: To evaluate the inter and intraobserver agreement of the Magerl AO and AOSpine thoracolumbar fracture classification systems. Methods: The participants were divided into two groups, the first composed of six spinal surgeons and the other composed of 18 medical orthopedic residents. On two different occasions, separated by an interval of one month, the participants analyzed and classified 25 radiographs with thoracolumbar fractures using both thoracolumbar fracture classification systems, Magerl AO and AOSpine. The results were analyzed for classification reliability using the Kappa coefficient (k). Results: The Magerl AO classification system showed a fair interobserver agreement (k = 0.32), considering the fractures type and subtype, whereas the AOSpine classification system showed a moderate interobserver agreement (k = 0.59). The Magerl AO classification showed a fair intraobserver agreement for both residents and specialists (k = 0.21 and 0.38, respectively), while the AOSpine showed a substantial agreement between residents (k = 0.62) and moderate between specialists (k = 0.53). Conclusions: When evaluating fracture morphology, the AOSpine thoracolumbar fracture classification system presented a better reliability and reproducibility compared to the Magerl AO classification system

System Dynamics model of interdisciplinary interaction between information specialists.

<p>The boxes (“stocks”) represent an accumulation of an element over time. For example: ‘number of information specialists’ represents a stock. Thick arrows (flows) represent the rate of influx or efflux of a stock over time and the thin arrows represent the relationship between the elements of the system. The +/− sign at the end of arrows indicate a positive/reinforcing and negative/balancing effect respectively. For example: Each of the themes – definitions, prolepsis, metaphors and analogies and thought experiments have a positive effect on communication while a difference in mental models has a negative effect on communication.</p