11,830 research outputs found
Comparative analysis of Mycobacterium tuberculosis pe and ppe genes reveals high sequence variation and an apparent absence of selective constraints.
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110619.pdf (Publisher’s version ) (Open Access)Mycobacterium tuberculosis complex (MTBC) genomes contain 2 large gene families termed pe and ppe. The function of pe/ppe proteins remains enigmatic but studies suggest that they are secreted or cell surface associated and are involved in bacterial virulence. Previous studies have also shown that some pe/ppe genes are polymorphic, a finding that suggests involvement in antigenic variation. Using comparative sequence analysis of 18 publicly available MTBC whole genome sequences, we have performed alignments of 33 pe (excluding pe_pgrs) and 66 ppe genes in order to detect the frequency and nature of genetic variation. This work has been supplemented by whole gene sequencing of 14 pe/ppe (including 5 pe_pgrs) genes in a cohort of 40 diverse and well defined clinical isolates covering all the main lineages of the M. tuberculosis phylogenetic tree. We show that nsSNP's in pe (excluding pgrs) and ppe genes are 3.0 and 3.3 times higher than in non-pe/ppe genes respectively and that numerous other mutation types are also present at a high frequency. It has previously been shown that non-pe/ppe M. tuberculosis genes display a remarkably low level of purifying selection. Here, we also show that compared to these genes those of the pe/ppe families show a further reduction of selection pressure that suggests neutral evolution. This is inconsistent with the positive selection pressure of "classical" antigenic variation. Finally, by analyzing such a large number of genes we were able to detect large differences in mutation type and frequency between both individual genes and gene sub-families. The high variation rates and absence of selective constraints provides valuable insights into potential pe/ppe function. Since pe/ppe proteins are highly antigenic and have been studied as potential vaccine components these results should also prove informative for aspects of M. tuberculosis vaccine design
Six Encounters
No full textSix poems by Simon Smith with six watercolour paintings by Felicity Allen. Online publication only
Eugene Smith
No full textImage shows a photograph of part of the Rock Canyon (Provo) CCC Camp.Eugene Smith, the donor of this photo, was enrolled in the CCC in 1939 at the Rock Canyon (Provo) Camp. The Rock Canyon Camp worked in conjunction with the U. S. Forest Service (F) and an unknown government entity (PE)
The Photograph of the Prince
No full textIn ROAD STORIES nine authors turn their attention to Exhibition Road, drawing inspiration from its famous institutions, collections, colleges and parks, as well as the lives of its residents. These specially commissioned pieces celebrate the diversity and richness of Exhibition Road in prose that is by turns lyrical and comical, contemplative and provocative. The result is a truly memorable and surprising collection by some of our most exciting and acclaimed writers: Ali Smith, Deborah Levy, Kamila Shamsie, Russell Hoban, Clare Wigfall, Eleanor Thom, Abdulrazak Gurnah, Hanan Al-Shaykh and Iain Sinclai
A socio-ecological approach to understanding adolescent girls' engagement and experiences in the PE environment : a case study design
No full textAdolescence is known to be a period of increased risk for the development of unhealthy behaviours such as physical inactivity (Currie et al., 2011). Low physical activity (PA) levels are especially noted in girls, who typically engage in less PA than boys throughout the teenage years (Whitehead and Biddle 2008). In Scotland, evidence suggests there is a significant decline in PA among adolescent girls, with only 41% of 13−15 year olds achieving the current recommendations, compared with 56% of 11−12 year olds (Scottish Executive, 2011). In addition, a proportion of girls are not engaging with school PE classes (Niven et al., 2014; Kirby et al., 2012). In order to understand more about how and why this decline exists, a sample of 20 ‘disengaged’ 12−13-year-old girls (second year of secondary school) were recruited from four case study schools in Scotland. This study aims to explore the interaction between the social and physical environment, and how these affect disengaged girls’ experiences and engagement in PE. Girls were categorised as ‘disengaged’ from PE if they did not participate regularly and reported negative emotions about the subject. Girls took part in in-depth interviews to explore their experiences and engagement in PE. The theoretical framework is based on Welks (1999) Youth Physical Activity Promotion model (YPAP), a socio-ecological approach which conceptualises the influential correlates of PA as: individual-level predisposing and enabling factors, including personal attributes and environmental variables and reinforcing (social) factors. This model was applied within a Scottish education context to understand the importance of each component and also the interaction between these and the influence that one may have on another. The results indicate that although the type of activity offered in PE is important, it appears that perceptions of competence and the social environment these were delivered in, such as single-sex classes, had more of an influence on girls’ engagement in PE. For this group of Scottish adolescent girls, the wider psychosocial environment in which PE takes place may have a greater impact on levels of enjoyment and participation than the PA itself.Peer reviewe
Special issue on "Reporting war"
No full textMichael Higgins and Angela Smith provide a special issue on reporting war
Assessment of the predictive and concurrent validity of the bilingual English Spanish oral screener
No full textTo properly measure the linguistic abilities of English-Spanish bilingual children it is necessary to assess them in both languages (Bedore and Pe’±a et al, 2012). Current assessment tools fail to accurately capture the language development of English-Spanish bilingual children because test items are reflective of the mainstream culture and therefore performance evaluations may not reflect the linguistic skills of children outside the mainstream norms (Pe’±a and Halle, 2011). The Bilingual English Spanish Oral Screener (BESOS) is a tool that was specifically developed to tap into the crucial milestones of language acquisition of dual language speakers of English and Spanish. The screening test is currently in the process of standardization and validation and its validity in predicting later problems in language or literacy development has not yet been established (Bedore et al. , 2012). The objective of the present thesis is the investigation of the predictive validity of the BESOS screening test on reading comprehension in a large longitudinal sample of Hispanic children (N=96) with different levels of input and use of English and Spanish. The predictive validity of the BESOS was assessed by measuring the relationship between participants\u27 scores on the screener at preschool and their performance on the Woodcock-Johnson III Reading Achievement Test at the end of first grade. Results demonstrated that the BESOS is an effective predictive measure of English-Spanish bilingual children\u27s English reading comprehension at the end of first grade. The analyses also showed that the BESOS possesses good concurrent validity with existing measures of English vocabulary and syntax and may be able to identify children at risk for low English literacy. Additional analyses revealed that Spanish language input and use at home are crucial factors for continued Spanish language development while age plays a larger role in the acquisition of English. These results demonstrate that the BESOS is an excellent 3 assessment tool for measuring the language development of English-Spanish bilingual preschoolers between the ages of 3 ½ and 6
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