New Perspectives on Democratic Education for the 21st Century Classroom

Ignit

An Experimental Study of a Pulsed DC Plasma Flow Control Actuator

An experiment on the effects of a pulsed DC plasma actuator on a separated flow in a low speed wind tunnel was conducted. The actuator consisted of two asymmetric copper electrodes oriented normal to the flow separated by a dielectric barrier and mounted on a flat plate in the center of the tunnel. A contoured insert was constructed and used to create an adverse pressure gradient in the test section comparable to a Pak-B low pressure turbine blade distribution. Suction was applied from the upper wall to induce separation along the flat plate over the electrodes. The DC power supply was kept constant at 8.5 kV and power was regulated through a high voltage fast transistor switch. The pulse width of the switch remained at 250 ns with the frequency ranging from 25 to 100 Hz. All studies were conducted at a Reynolds number of 30,000 to simulate takeoff and other low speed conditions. It was found that the DC pulsed plasma actuator could reattach the flow but not consistently at these conditions. Furthermore no evidence was found to indicate that coherent vortical structures are responsible for reenergizing the boundary layer and controlling separatio

What’s old is new again: The sacroiliac joint as a cause of lateralizing low back pain

It has not been easy to identify mechanical failure of the sacroiliac joint (SIJ) with traditional imaging. The integrated model of function (Lee and Vleeming, 1998) suggests that under normal circumstances, form and force closure combined contribute to sacral nutation and “locking” the SIJ for optimal load transfer. This model is supported by clinical evidence and scintigraphic findings that contribute to successful therapy in 80% of cases. Single-photon emission computed tomography and x-ray computed tomography (SPECT-CT), a hybrid device, was used in a study of 1200 patients (64% female and 36% male patients with an average age of 42 years; range, 15–78 years) with a clinical diagnosis of SIJ incompetence (pelvic girdle pain syndrome). Standard clinical testing and an alternate series of tests were used as a reference standard for imaging. Symptoms were present for a mean of 43 months. Imaging finding were of increased uptake in the upper SIJ (S1–S2), with extension into the dorsal interosseous ligament and measurable by count profile. Associated findings of tendon enthesopathy reflected altered biomechanics around the pelvis. Ipsilateral adductor enthesopathy was found in 70% and contralateral hamstring enthesopathy in 60% of patients. SPECT-CT criteria for the diagnosis of SIJ incompetence were developed and validated. SPECT-CT is a valid and reproducible technique for the diagnosis of SIJ incompetence with high concordance and specificity compared to the reference standards. Findings are supportive of the integrated model of SIJ function proposed by Lee and Vleeming

Measuring Trust in Medical Researchers: Comparing Agree-Disagree and Construct-Specific Survey Questions

While scales measuring subjective constructs historically rely on agree-disagree (AD) questions, recent research demonstrates that construct-specific (CS) questions clarify underlying response dimensions that AD questions leave implicit and CS questions often yield higher measures of data quality. Given acknowledged issues with AD questions and certain established advantages of CS items, the evidence for the superiority of CS questions is more mixed than one might expect. We build on previous investigations by using cognitive interviewing to deepen understanding of AD and CS response processing and potential sources of measurement error. We randomized 64 participants to receive an AD or CS version of a scale measuring trust in medical researchers. We examine several indicators of data quality and cognitive response processing including: reliability, concurrent validity, recency, response latencies, and indicators of response processing difficulties (e.g., uncodable answers). Overall, results indicate reliability is higher for the AD scale, neither scale is more valid, and the CS scale is more susceptible to recency effects for certain questions. Results for response latencies and behavioral indicators provide evidence that the CS questions promote deeper processing. Qualitative analysis reveals five sources of difficulties with response processing that shed light on under-examined reasons why AD and CS questions can produce different results, with CS not always yielding higher measures of data quality than AD

Business Ethnography: Inducing Liminality in Pursuit of Innovation

Ethnographic studies have become an integral part of many projects at Xerox: guiding product improvements, inspiring new product concepts, uncovering technology and organizational issues, and informing strategic directions. Ethnographic methods provide a deep understanding of technology usage in context and have the potential to shift the perspectives of the researchers themselves, the study participants, and the business stakeholders. These transformations facilitate the creation of innovative solutions that are meaningful and useful for the practitioners they are designed to support. In this article, we draw on three case studies to demonstrate how ethnographic methods invoke liminality, and how these studies support transformation in the perspectives of the researchers, practitioners, and stakeholders who participate in the studies

Alternatively certified and traditionally certified secondary school mathematics teachers' student success on the Missouri Assessment Program

Title from PDF of title page, viewed on May 14, 2012Dissertation advisor: Rita BargerVitaIncludes bibliographic references (p. 106-112)Thesis (Ph.D.)--School of Education and Dept. of Mathematics. University of Missouri--Kansas City, 2009Since the 1980s, alternative certification programs, with the goals of improving the quality and quantity of teachers, have been preparing teachers through streamlined coursework tailored to the individual teachers' needs. Meanwhile, to improve teacher quality, traditional teacher education programs have been increasing standards required for traditional certification. These competing views on how to improve teacher quality have led to debates on the effectiveness of alternative certification programs and the teachers they certify. This study aimed to gain insight into the effectiveness of alternatively certified secondary mathematics teachers from two alternative certification programs offered at two universities. Alternatively certified secondary mathematics teachers from these programs were recruited to participate, and when possible traditionally certified secondary mathematics teachers in the same schools as participating alternatively certified teachers were also involved in the study. Data were collected on the participating teachers' students' 2008 state achievement mathematics test scores. Using analysis of variance and analysis of covariance tests, the data revealed that, on average, students of the alternatively certified teachers outperformed the students of traditionally certified teachers. Factors that had a significant impact on students' 2008 test scores were students' previous score on the test, students' minority status, and teachers' certification route. While these factors were all significant, students' previous scores accounted for the largest portion of the variance in 2008 scores, and teachers' certification route accounted for the smallest portion. Teachers' number of years of experience was not found to have an impact on students test scores, nor was there a significant interaction between teachers' certification route and students' gender.Introduction-- Review of literature -- Methodology -- Results -- Discussion -- Appendix A -- Appendix B -- Appendix C -- Appendix

Immune reconstitution syndrome in HIV: validating a case definition and identifying clinical predictors in persons initiating antiretroviral therapy

Background: Clinical deterioration after initiation of antiretroviral therapy may result from restored immunity. There is no standard clinical definition for immune reconstitution syndrome. The objectives of this study were to validate a proposed definition and to identify factors predictive of immune reconstitution syndrome. Methods: This was a retrospective case-control study from an academic university medical practice. Cases were matched to ⩾2 control subjects by CD4+ cell count at the time of initiation of antiretroviral therapy. Cases and “mock cases” were blindly reviewed by 2 human immunodeficiency virus (HIV) experts. Results: Twenty possible cases of immune reconstitution syndrome were identified; HIV experts excluded all cases of herpes zoster (shingles), with agreement on real and mock cases of 92%. For 14 confirmed case patients (compared with 40 control subjects), immune reconstitution syndrome was associated with a higher number of prior opportunistic infections (P = .003) and higher CD8+ cell counts at baseline (P = .05) and at week 12 (P = .02). Immune reconstitution syndrome was associated with lower baseline levels of alanine aminotransferase (P = .05) and hemoglobin (P = .02). On multivariate analysis, the number of prior opportunistic infections (odds ratio, 2.7; P = .007) and lower hemoglobin level at baseline (odds ratio, 0.8; P = .003) were independently associated with development of immune reconstitution syndrome. A predictive model was defined by classification and regression tree analysis with a sensitivity and specificity of 78.57% and 87.50%, respectively, for an importance score of ⩾4 (on a scale of 0.0 to 100.0), and 92.86% and 80.00%, respectively, for a score of ⩾2, using the number of prior opportunistic infections, CD8+ cell count, and hemoglobin level. Conclusions: A standard definition for immune reconstitution syndrome is possible. Patients with a greater severity of illness at initiation of antiretroviral therapy are at risk for immune reconstitution syndrome. The model defined by classification and regression tree analysis may provide a basis for risk stratification before initiation of antiretroviral therapy

Predictors of initiation and persistence of unhealthy weight control behaviours in adolescents

<p>Abstract</p> <p>Background</p> <p>Unhealthy weight control behaviours (UWCB) among adolescents have significant health and weight consequences. The current longitudinal study aimed to identify personal and socio-environmental predictors of initiation or persistence of adolescent UWCB, in order to inform development of programs aimed at both preventing and stopping UWCB.</p> <p>Methods</p> <p>A diverse sample included 1106 boys and 1362 girls from 31 middle schools and high schools in the United States who were enrolled in Project EAT (Eating Among Teens). Project EAT explored personal, behavioural, and socio-environmental factors associated with dietary intake and body weight in adolescence. Participants completed questionnaires to assess demographics, UWCB (including several methods of food restriction, purging by vomiting or medications, smoking to control weight, or food substitutions) and personal and socio-environmental variables at two time points, five years apart, between 1998 and 2004. Logistic regression models examined personal and socio-environmental predictors of initiation and persistence of UWCB among Project EAT participants.</p> <p>Results</p> <p>Results indicate that 15.5% of boys and 19.7% of girls initiated UWCB by Time 2, and 15.9% of boys and 43.3% of girls persisted with these behaviours from Time 1 to Time 2. After controlling for race/ethnicity and weight status changes between assessments, logistic regression models indicated that similar factors and patterns of factors were associated significantly with initiation and persistence of UWCB. For both boys and girls, personal factors had more predictive value than socio-environmental factors (Initiation models: for boys: <it>R</it>²= 0.35 for personal vs. 0.27 for socio-environmental factors; for girls, <it>R</it>²= 0.46 for personal vs. 0.26 for socio-environmental factors. Persistence models: for boys: <it>R</it>²= 0.53 for personal vs. 0.33 for socio-environmental factors; for girls, <it>R</it>²= 0.41 for personal vs. 0.19 for socio-environmental factors). The weight concerns model was the strongest predictor among all individual models [Initiation odds ratios (ORs) and 95% confidence interval (CI): 4.84 (3.32-7.01) for boys and 5.09 (3.55-7.30) for girls; persistence OR (CI): 4.55 (2.86-7.14) for boys and 3.45 (2.50-4.76) for girls].</p> <p>Conclusion</p> <p>In general, predictors of initiation and persistence of UWCB were similar, suggesting that universal and selective prevention programs can target similar risk factors.</p