Examination of the Six Minute Walk Test to Determine Functional Capacity in People with Chronic Heart Failure: A Systematic Review

Purpose: To evaluate the reliability and validity of the six-minute walk test (6MWT) with respect to its ability to predict functional capacity in patients with chronic heart failure. Methods: A systematic review was performed via 8 databases to assess relevant English language full-text articles published from January 1, 1980 to October 31, 2009. Participant characteristics, interventions, reliability, validity, and predictive value for each article with respect to functional capacity as defined by peak VO₂ levels were extracted and compared. Quality Assessment of Diagnostic Accuracy Studies (QUADAS) scores were determined for each study. Results: Fourteen studies met the selection criteria. Comparison of the studies investigating reliability shows that the 6MWT has good reproducibility. The 6MWT demonstrates moderate correlation with peak VO₂ levels, and ability to predict VO₂ (functional capacity) dependent on distance walked. Cut-off distances vary from 300 to 490 meters depending on the study; if total distance walked remains equal or less than these values, the 6MWT retains its strong predictive value. Conclusion: The 6MWT has good reliability, moderate validity, and a significant ability to predict functional capacity in patients with CHF who do not walk greater than 490 meters.Key Words: six-minute walk test, chronic heart failure, functional capacity, peak VO₂     

Science identity trajectories throughout school visits to a science museum

Research has repeatedly demonstrated how informal learning environments afford science-identity development by fostering a broader array of interactions and recognizing more varied participation modes and roles, as compared to the classroom. Thus, science teachers are encouraged to take students to field trips in informal environments, including science museums. However, the question of whether and how informal environments indeed support science identities also in a schooling context (i.e., in field trips) has not yet been explored. This case study addresses this question by analyzing identity trajectories of three students throughout six school visits to an Israeli science museum. We observed and recorded these students in the museum over the course of 3 years (fourth to sixth grade). We also visited their school and interviewed them after each visit. Drawing on a sociocultural interactional approach to identity, we analyzed 18 hr of video and audio recordings, tracking the participation of the three students across time and contexts, comparing between the students, points in time and settings, including structured (museum lab), semi-structured (riddle-solving activities in exhibition halls), and unstructured settings (free exploration). We employed linguistic ethnographic methods and microanalysis to examine the ways in which the students participated and their positioning by self and others. While we found differences between settings within the museum, overall, the findings show that the museum reproduced the school's interaction, positioning, and roles. The “(non)science person” in school was also the “(non)science person” in the museum, and thus, the museum visits did not appear to shift identity trajectories. These findings challenge the premise that informal environments support the development of science identities also in a schooling context and call for a more critical view of such fieldtrips in terms of their pedagogical and physical design, facilitation approach, and consideration of peers' social interaction.     

Principal transformative learning through mentoring aspiring administrators

Few researchers have explicitly examined the benefits to practicing principals engaged in mentoring aspiring principals. Through the lens of transformative learning, the purpose of our study was to examine the professional learning of practicing principals engaged as mentors with aspiring principals in a leadership preparation program. Two questions guided our study. First, how does engaging in the mentoring process lead to professional learning? Second, how does that learning manifest itself in principal practice? Findings suggested principal mentor/protégé and mentor/mentor interactions prompted mentors to question their own experiences and practices, problematizing some of these practices. Principals then generated solutions, which lead to changes in core beliefs and assumptions and finally changes in practices, reflective of transformative learning.     

Parental Ethnic-Racial Socialization and Children of Color's Academic Success: A Meta-Analytic Review

Increased attention is being placed on the importance of ethnic-racial socialization in children of color's academic outcomes. Synthesizing research on the effects of parental ethnic-racial socialization, this meta-analysis of 37 studies reveals that overall the relation between ethnic-racial socialization and academic outcomes was positive, though the strength varied by the specific academic outcome under consideration, dimension of ethnic-racial socialization utilized, developmental age of the child receiving the socialization, and racial/ethnic group implementing the socialization. Ethnic-racial socialization was positively related to academic performance, motivation, and engagement, with motivation being the strongest outcome. Most dimensions of ethnic-racial socialization were positively related to academic outcomes, except for promotion of mistrust. In addition, the link between ethnic-racial socialization and academic outcomes was strongest for middle school and college students, and when looking across ethnic-racial groups, this link was strongest for African American youth. The results suggest that different dimensions of ethnic-racial socialization have distinct relationships with diverse academic outcomes and that the effects of ethnic-racial socialization vary by both youth developmental levels and racial/ethnic groups.     

Bidirectional delta files

A bidirectional delta file is a novel concept, introduced in this paper, for a two way delta file. Previous work focuses on single way differential compression called forwards and backwards delta files. Here we suggest to efficiently combine them into a single file so that the combined file is smaller than the combination of the two individual ones. Given the bidirectional delta file of two files S and T and the original file S, one can decode it in order to produce T. The same bidirectional delta file is used together with the file T in order to reconstruct S. This paper presents two main strategies for producing an efficient bidirectional delta file in terms of the memory storage it requires; a quadratic time, optimal, dynamic programming algorithm, and a linear time, greedy algorithm. Although the dynamic programming algorithm often produces better results than the greedy algorithm, it is impractical for large files, and it is only used for theoretical comparisons. Experiments between the implemented algorithms and the traditional way of using both forwards and backwards delta files are presented, comparing their processing time and their compression performance. These experiments show memory storage savings of about 25% using this bidirectional delta approach as compared to the compressed delta file constructed using the traditional way, while preserving approximately the same processing time for decoding.     

当有家人患癌症

去年,我接受了前列腺癌的治疗,这个过程让我感觉如同一座房子的分崩离析。而且,很长一段时间,我能否康复都不甚明朗。但是在这个我逼视自己内心的过程中,我认识到了最重要的一件事情——不光是我一个人,而是我的整个家庭都因为这个病而发生变化。