School engagement,risky peers,and student–teacher relationships as mediators of school violence in Taiwanese vocational versus academically oriented high schools

Educational tracking based on academic ability accounts for different school dynamics between vocational versus academically‐oriented high schools in Taiwan. Many educational practitioners predict that the settings of vocational schools and academic schools mediate school violence in different ways. Alternatively, some researchers argue the actual mediating mechanism may not vary significantly between the different school types in different cultures. The purpose of this study was to examine how within‐school variables (school engagement, risky peers, and student–teacher interaction) mediate external‐school variables (personal traits, parental monitoring, and victimization) and school violence in Taiwanese vocational and academically‐oriented schools. Structural equation modeling analysis, based on a national representative sample (N=7,841), suggested school violence was mediated through school variables. Similar mediational findings were found between academic and vocational schools as well as between males and females. Findings suggest that school violence is mediated by within‐school variables in similar ways across different school types, genders, and cultures. © 2010 Wiley Periodicals, Inc.     

Comparison of different MRI sequences in lesion detection and early response evaluation of diffuse large B‐cell lymphoma – a whole‐body MRI and diffusion‐weighted imaging study

To compare different MRI sequences for the detection of lesions and the evaluation of response to chemotherapy in patients with diffuse large B‐cell lymphoma (DLBCL), 18 patients with histology‐confirmed DLBCL underwent 3‐T MRI scanning prior to and 1 week after chemotherapy. The MRI sequences included T₁‐weighted pre‐ and post‐contrast, T₂‐weighted with and without fat suppression, and a single‐shot echo‐planar diffusion‐weighted imaging (DWI) with two b values (0 and 800 s/mm²). Conventional MRI sequence comparisons were performed using the contrast ratio between tumor and normal vertebral body instead of signal intensity. The apparent diffusion coefficient (ADC) of the tumor was measured directly on the parametric ADC map. The tumor volume was used as a reference for the evaluation of chemotherapy response. The mean tumor volume was 374 mL at baseline, and decreased by 65% 1 week after chemotherapy (p < 0.01). The T₂‐weighted image with fat suppression showed a significantly higher contrast ratio compared with images from all other conventional MRI sequences, both before and after treatment (p < 0.01, respectively). The contrast ratio of the T₂‐weighted image with fat suppression decreased significantly (p < 0.01), and that of the T₁‐weighted pre‐contrast image increased significantly (p < 0.01), after treatment. However, there was no correlation between the change in contrast ratio and tumor volume. The mean ADC value was 0.68 × 10^–3 mm²/s at baseline; it increased by 89% after chemotherapy (p < 0.001), and the change in ADC value correlated with the change in tumor volume (r = 0.66, p < 0.01). The baseline ADC value also correlated inversely with the percentage change in ADC after treatment (r = ?0.62, p < 0.01). In conclusion, this study indicates that T₂‐weighted imaging with fat suppression is the best conventional sequence for the detection of lesions and evaluation of the efficacy of chemotherapy in DLBCL. DWI with ADC mapping is an imaging modality with both diagnostic and prognostic value that could complement conventional MRI. Copyright © 2013 John Wiley & Sons, Ltd.