A dosimetry and radiobiological model for intravascular brachytherapy treatment planning with radioisotope emitting stents

The aim of this study was to develop a practical, versatile and fast dosimetry and radiobiological model for calculation of the 3D dose distribution and radiobiological effectiveness of radioactive stents. The algorithm was written in Matlab 6.5 programming language and is based on the dose point kernel convolution. The dosimetry and radiobiological model was applied for evaluation of the 3D dose distribution of 32P, 90Y, 188Re and 177Lu stents. Of the four, 32P delivers the highest dose, while 90Y, 188Re and 177Lu require high levels of activity to deliver a significant therapeutic dose in the range of 15-30 Gy. Results of the radiobiological model demonstrated that the same physical dose delivered by different radioisotopes produces significantly different radiobiological effects. This type of theoretical dose calculation can be useful in the development of new stent designs, the planning of animal studies and clinical trials, and clinical decisions involving individualized treatment plans.

The relationship between classroom interactions and exclusionary discipline as a social practice: A critical microethnograhy

Exclusionary school discipline results in students being removed from classrooms as a consequence of their disruptive behavior and may lead to subsequent suspension and/or expulsion. Literature documents that nondominant students, particularly Black males, are disproportionately impacted by exclusionary discipline, to the point that researchers from a variety of critical perspectives consider exclusionary school discipline an oppressive educational practice and condition. Little or no research examines specific teacher-student social interactions within classrooms that influence teachers’ decisions to use or not use exclusionary discipline. Therefore, this study set forth the central research question: In relation to classroom interactions in alternative education settings, what accounts for teachers’ use or non-use of exclusionary discipline with students? A critical social practice theory of learning served as the framework for exploring this question, and a critical microethnographic methodology informed the data collection and analysis. ^ Criterion sampling was used to select four classrooms in the same alternative education school with two teachers who frequently and two who rarely used exclusionary discipline. Nine stages of data collection and reconstructive data analysis were conducted. Data collection involved video recorded classroom observations, digitally recorded interviews of teachers and students discussing selected video segments, and individual teacher interviews. Reconstructive data analysis procedures involved hermeneutic inferencing of possible underlying meanings, critical discourse analysis, interactive power analysis and role analysis, thematic analysis of the interactions in each classroom, and a final comparative analysis of the four classrooms. ^ Four predominant themes of social interaction (resistance, conformism, accommodation, and negotiation) emerged with terminology adapted from Giroux’s (2001) theory of resistance in education and Third Space theory (Gutiérrez, 2008). Four types of power (normative, coercive, interactively established contracts, and charm), based on Carspecken’s (1996) typology, were found in the interactions between teacher and students in varying degrees for different purposes. ^ This research contributes to the knowledge base on teacher-student classroom interactions, specifically in relation to exclusionary discipline. Understanding how the themes and varying power relations influence their decisions and actions may enable teachers to reduce use of exclusionary discipline and remain focused on positive teacher-student academic interactions. ^

A visual critical ethnography of youth develoment in a Rio de Janeiro favela

Favelas are Brazilian informal housing settlements that are areas of concentrated poverty. In Rio de Janeiro, favelas are perceived as areas of heightened criminal activity and violence, and residents experience discrimination, and little access to quality education and employment opportunities. In this context, hundreds of non-formal educational arts and leisure programs work to build the self-esteem and identity of youth in Rio's favelas as a way of preventing the youth from negative local influences. The Morrinho organization, located in the Pereira da Silva favela in Rio, uses art as a way for the local male youth to communicate their lived reality. This study used a visual critical ethnographic methodology to describe the way in which the Morrinho participants interpret living in a favela. Seventeen semi-structured interviews with young men aged 15 to 29, the feature-length documentary film on the organization, 206 researcher produced documentary style photographs of the Morrinho artwork, and the researcher's field notes were analyzed. Truth claims, ways of seeing as communicated through words and actions, were induced through a cyclical process of reconstructive horizon analysis that incorporated the societal context and critical theory. The participants communicated their concerns about life in a favela; however, they did not describe their societal positions in terms of complete marginalization. They named multiple benefits of living in Pereira da Silva, discussed positive and negative experiences in school, and described ways they circumvented discrimination. Morrinho as an organization was described as an enthralling game and a social project that benefited dozens of local youth. Character development was a valuable result of participation at Morrinho. The Morrinho artwork communicates a nuanced vision of both benevolent and violent social actors, and counters the overwhelmingly negative dominant characterization of Rio de Janeiro's favelas. This study has implications for an inclusive critical pedagogy and the use of art as a means to facilitate a transformative education. Further research is recommended to explore terminology used to refer to favelas, and perceptions that favela residents have of their experiences in public education.

The Relationship between Classroom Interactions and Exclusionary Discipline as a Social Practice: A Critical Microethnography

Exclusionary school discipline results in students being removed from classrooms as a consequence of their disruptive behavior and may lead to subsequent suspension and/or expulsion. Literature documents that nondominant students, particularly Black males, are disproportionately impacted by exclusionary discipline, to the point that researchers from a variety of critical perspectives consider exclusionary school discipline an oppressive educational practice and condition. Little or no research examines specific teacher-student social interactions within classrooms that influence teachers’ decisions to use or not use exclusionary discipline. Therefore, this study set forth the central research question: In relation to classroom interactions in alternative education settings, what accounts for teachers’ use or non-use of exclusionary discipline with students? A critical social practice theory of learning served as the framework for exploring this question, and a critical microethnographic methodology informed the data collection and analysis. Criterion sampling was used to select four classrooms in the same alternative education school with two teachers who frequently and two who rarely used exclusionary discipline. Nine stages of data collection and reconstructive data analysis were conducted. Data collection involved video recorded classroom observations, digitally recorded interviews of teachers and students discussing selected video segments, and individual teacher interviews. Reconstructive data analysis procedures involved hermeneutic inferencing of possible underlying meanings, critical discourse analysis, interactive power analysis and role analysis, thematic analysis of the interactions in each classroom, and a final comparative analysis of the four classrooms. Four predominant themes of social interaction (resistance, conformism, accommodation, and negotiation) emerged with terminology adapted from Giroux’s (2001) theory of resistance in education and Third Space theory (Gutiérrez, 2008). Four types of power (normative, coercive, interactively established contracts, and charm), based on Carspecken’s (1996) typology, were found in the interactions between teacher and students in varying degrees for different purposes. This research contributes to the knowledge base on teacher-student classroom interactions, specifically in relation to exclusionary discipline. Understanding how the themes and varying power relations influence their decisions and actions may enable teachers to reduce use of exclusionary discipline and remain focused on positive teacher-student academic interactions.