Surface critical exponents at a uniaxial Lifshitz point

Using Monte Carlo techniques, the surface critical behaviour of three-dimensional semi-infinite ANNNI models with different surface orientations with respect to the axis of competing interactions is investigated. Special attention is thereby paid to the surface criticality at the bulk uniaxial Lifshitz point encountered in this model. The presented Monte Carlo results show that the mean-field description of semi-infinite ANNNI models is qualitatively correct. Lifshitz point surface critical exponents at the ordinary transition are found to depend on the surface orientation. At the special transition point, however, no clear dependency of the critical exponents on the surface orientation is revealed. The values of the surface critical exponents presented in this study are the first estimates available beyond mean-field theory.Comment: 10 pages, 7 figures include

An intact canonical NF-κB pathway is required for inflammatory gene expression in response to hypoxia

Hypoxia is a feature of the microenvironment in a number of chronic inflammatory conditions due to increased metabolic activity and disrupted perfusion at the inflamed site. Hypoxia contributes to inflammation through the regulation of gene expression via key oxygen-sensitive transcriptional regulators including the hypoxia-inducible factor (HIF) and NF-κB. Recent studies have revealed a high degree of interdependence between HIF and NF-κB signaling; however, the relative contribution of each to hypoxiainduced inflammatory gene expression remains unclear. In this study, we use transgenic mice expressing luciferase under the control of NF-κB to demonstrate that hypoxia activates NF-κB in the heart and lungs of mice in vivo. Using small interfering RNA targeted to the p65 subunit of NF-κB, we confirm a unidirectional dependence of hypoxic HIF-1α accumulation upon an intact canonical NF-κB pathway in cultured cells. Cyclooxygenase-2 and other key proinflammatory genes are transcriptionally induced by hypoxia in a manner that is both HIF-1 and NF-κB dependent, and in mouse embryonic fibroblasts lacking an intact canonical NF-κB pathway, there is a loss of hypoxia-induced inflammatory gene expression. Finally, under conditions of hypoxia, HIF-1α and the p65 subunit of NF-κB directly bind to the cyclooxygenase-2 promoter. These results implicate an essential role for NF-κB signaling in inflammatory gene expression in response to hypoxia both through the regulation of HIF-1 and through direct effects upon target gene expression. Copyright©2011 by The American Association of Immunologists, Inc

The challenges of the Ontario Secondary School Literacy Test for second language students

Results from the Ontario Secondary School Literacy Test (OSSLT) indicate that English as a Second Language (ESL) and English Literacy Development (ELD) students have comparatively low success and high deferral rates. This study examined the 2002 and 2003 OSSLT test performances of ESL/ELD and non-ESL/ELD students in order to identify and understand the factors that may help explain why ESL/ELD students failed the test at relatively high rates. The analyses also attempted to determine if there were significant and systematic differences in ESL/ELD students' test performance. The performance of ESL/ELD students was consistently and similarly lower across item formats, reading text types, skills and strategies, and the four writing tasks. Using discriminant analyses, it was found that narrative text type, indirect understanding skill, vocabulary strategy of reading, and the news report writing task were significant predictors of ESL/ELD membership. The results of this study provide direction for further research and instruction regarding English literacy achievement for these second language students within the context of having to complete large-scale English literacy tests designed and constructed for first English language students