106 resultados para Motif U-turn
Resumo:
Polyisoprenyl-phosphate N-acetylaminosugar-1-phosphate transferases (PNPTs) constitute a family of eukaryotic and prokaryotic membrane proteins that catalyze the transfer of a sugar-1-phosphate to a phosphoisoprenyl lipid carrier. All PNPT members share a highly conserved 213-Valine-Phenylalanine-Methionine-Glycine-Aspartic acid-217 (VFMGD) motif. Previous studies using the MraY protein suggested that the aspartic acid residue in this motif, D267, is a nucleophile for a proposed double-displacement mechanism involving the cleavage of the phosphoanhydride bond of the nucleoside. Here, we demonstrate that the corresponding residue in the E. coli WecA, D217, is not directly involved in catalysis, as its replacement by asparagine results in a more active enzyme. Kinetic data indicate that the D217N replacement leads to more than twofold increase in V(max) without significant change in the K(m) for the nucleoside sugar substrate. Furthermore, no differences in the binding of the reaction intermediate analog tunicamycin were found in D217N as well as in other replacement mutants at the same position. We also found that alanine substitutions in various residues of the VFMGD motif affect to various degrees the enzymatic activity of WecA in vivo and in vitro. Together, our data suggest that the highly conserved VFMGD motif defines a common region in PNPT proteins that contributes to the active site and is likely involved in the release of the reaction product.
Resumo:
Drawing on material from the BBC Written Archive Centre, this article examines the earliest sf dramas broadcast by the BBC Television Service: two adaptations of Karel Capek's "R.U.R." ("Rossum's Universal Robots") from 1938 and 1948. These productions are used as sites of formal experimentation with the possibilities of the new medium, representing one aspect of contemporary debates about the purpose of television and the style it would assume.
Resumo:
Topic Background: Peace education initiatives in schools are often based on social psychological theories assuming that social identity affects ingroup and outgroup attitudes and, in turn, behaviors relating to relevant outgroups. However, research evidence on the role of children's social identity has often failed to take account of different social identity dimensions or to conceptualise behavior in the context of children's understandings of the social world. While recent research relating to bullying and bystander behavior amongst children has addressed the latter point, this has rarely been considered in conjunction with a differentiated view of social identity. This paper is therefore distinctive as it will address the role of social identity dimensions with regards to reported behavior as captured in bystander scenarios relating to outgroup derogation. This is particularly important in the context of divided societies, where peace education initiatives are crucial in promoting positive community relations for the future and where such initiative may be hampered by communities' concerns about loss of identity. In the context of Northern Ireland, a divided society emerging from conflict, social identity, outgroup attitudes and behaviours have been key concepts addressed by peace educators
for many years.
Research questions: This paper therefore set out to investigate the relationship between social identity, measured as affiliation with the group and exploration of its meaning for the child, sectarian attitudes and pupils' reported willingness to challenge sectarian bullying in their school environment in Northern Ireland.
Research methods: The findings are based on the analysis of a baseline survey, which forms part of a randomised control trial of an intervention aimed at promoting community relations and reconciliation. The trial includes 35 primary and post-primary schools and about 800 pupils from 8-11 years old who completed an online questionnaire at the start of the programme. Main instruments for this study included adapted scales measuring identity affiliation and identity exploration, sectarian attitudes and scenarios capturing pupils' intentions in bystander situations relating to sectarian bullying.
Analytical framework: Results are analysed using regression analysis and additionally investigate gender and religious differences.
Research findings and/or contribution to knowledge: Results are discussed in the light of the role of social identity dimensions and their relationship to outgroup attitudes and willingness to challenge outgroup derogation. The paper concludes with potential implications for peace education initiatives in Northern Ireland and beyond.
Resumo:
Peace education initiatives in schools are often based on social psychological theories assuming that social identity affects ingroup and outgroup attitudes and, in turn, behaviors relating to relevant outgroups. However, research evidence on the role of young people’s social identity has often failed to take account of different social identity dimensions or to conceptualise outgroup behavior in the context of young people’s understandings of the social world. While recent research relating to bullying and bystander behavior amongst young people has addressed the latter point, this has rarely been considered in conjunction with a differentiated view of social identity. This paper is therefore distinctive as it will address the role of social identity dimensions with regards to behavior as captured in bystander scenarios relating to intergroup discrimination. This is particularly important in the context of divided societies, where peace education initiatives are crucial in promoting positive community relations for the future and where such initiative may be hampered by communities’ concerns about loss of identity and hardened intergroup attitudes. Furthermore, previous research frequently highlighted teachers’ fears to tackle outgroup attitudes in the classroom, especially in contexts where pupils and the wider school community are seen as entrenched in community divisions (Hughes, Donnelly, Hewstone, Gallagher & Carlisle, 2010). However, there is no research investigating the relationship between pupils’ attitudes and teacher confidence to talk about such issues in the classroom, which is explored in this paper.
In the context of Northern Ireland, a divided society emerging from sectarian conflict, social identity, outgroup attitudes and outgroup behaviours have been key concepts addressed by peace educators for many years. Building on this work, this paper provides a detailed picture of young people’s strength of group identification and their willingness to explore ingroup perspectives, sectarian attitudes and their reported willingness to challenge sectarian bullying. Using data from a baseline survey, which forms part of a randomized control trial investigating the effect of an educational intervention aimed to promote reconciliation, the sample involved young people of different denominational backgrounds, attending separate school sectors. The baseline data will be used to compare with post intervention data. Therefore, the data and its findings would be of particular interest to educators and policy makers in other European countries who are working to develop peace education interventions in societies emerging from conflict. Additionally, this paper considers the results from a baseline teacher survey, collected before training and teaching of the intervention began. The teacher survey focused on confidence in tackling sectarian issues in the classroom, previous experience of teaching such issues and their hopes and concerns for the reconciliation intervention.
This paper therefore set out to investigate the relationship between dimensional concept of social identity, sectarian attitudes and pupils’ reported willingness to challenge sectarian bullying and to compare this with their teachers’ attitudes to teaching about sectarian issues in the classroom.
Method
The pupil sample included 35 primary and post-primary schools and about 800 pupils from 8-11 years old who completed an online questionnaire in December 2011 and January 2012. Main instruments for young people’s survey included an adapted version of the Multi-ethnic identity measure (Phinney, 1992) incorporating the dimensions identity affirmation and exploration, outgroup attitude scales, including an adaptation of the social distance measure (Bogardus, 1947), as well as a measure adapted from Palmer and Cameron (2011) involving scenarios to capture pupils’ intentions in bystander situations relating to intergroup discrimination. Results are analysed using regression analysis and take account of potential gender and religious differences. The teacher questionnaire was completed by the 35 primary and post-primary teachers who will deliver the intervention. Results are analysed in terms of how teachers’ responses compare with their pupil attitudes by considering their confidence in tackling sectarian issues in the classroom and how their previous experience and training relate to their hopes and concerns for the intervention.
Expected Outcomes
Results from the young people’s survey are discussed in the light of the role of social identity dimensions and their relationship to sectarian attitudes and reported bystander behaviour in sectarian school incidents. Furthermore, results related to pupils’ sectarian attitudes will be compared with teachers’ reported confidence in tackling sectarianism in the classroom. The teacher questionnaire also presents interesting findings in relation to teachers’ previous training and experience and how this may influence different perspectives on peace and reconciliation interventions and their expectations of what these could achieve. The paper concludes with potential implications for peace education initiatives and related teacher training in Northern Ireland and beyond. The implications will be of particular interest to policy makers, educators and those working in the area of peace education to design and implement interventions.
References
Bogardus, E. S. (1947) Measurement of Personal-Group Relations. Sociometry, 10: 4: 306–311. Hughes, J., Donnelly, C., Hewstone, M., Gallagher, T. & Carlisle, K. (2010) School partnerships and reconciliation: An evaluation of school collaboration in Northern Ireland. Belfast: Queen’s University Belfast. Available online: http://www.schoolsworkingtogether.com/documents/School%20collaboration%20in%20NI%202010.pdf. (accessed 27th Jan 2010) Palmer, S. & Cameron, L. (2011, May). What are the moderators and mediators of children’s bystander behaviour in the context of intergroup discrimination? Paper session presented at the UNA Global Biennial Conference 2011: Building Peaceable Communities: The Power of Early Childhood, Amsterdam, Holland. Phinney, J. S. (1992). The Multigroup Ethnic Identity Measure: A new scale for use with diverse groups. Journal of Adolescent Research, 7, 156–176.
Resumo:
We report the largest market basket survey of arsenic (As) in U.S. rice to date. Our findings show differences in transitional-metal levels between polished and unpolished rice and geographical variation in As and selenium (Se) between rice processed in California and the South Central U.S. The mean and median As grain levels for the South Central U.S. were 0.30 and 0.27 µg As g-1, respectively, for 107 samples. Levels for California were 41% lower than the South Central U.S., with a mean of 0.17 µg As g-1 and a median of 0.16 µg As g-1 for 27 samples. The mean and median Se grain levels for the South Central U.S. were 0.19 µg Se g-1. Californian rice levels were lower, averaging only 0.08 and 0.06 µg Se g-1 for mean and median values, respectively. The difference between the two regions was found to be significant for As and Se (General Linear Model (GLM):? As p < 0.001; Se p < 0.001). No statistically significant differences were observed in As or Se levels between polished and unpolished rice (GLM:? As p = 0.213; Se p = 0.113). No significant differences in grain levels of manganese (Mn), cobalt (Co), copper (Cu), or zinc (Zn) were observed between California and the South Central U.S. Modeling arsenic intake for the U.S. population based on this survey shows that for certain groups (namely Hispanics, Asians, sufferers of Celiac disease, and infants) dietary exposure to inorganic As from elevated levels in rice potentially exceeds the maximum intake of As from drinking water (based on consumption of 1 L of 0.01 mg L-1 In. As) and Californian state exposure limits. Further studies on the transformation of As in soil, grain As bioavailability in the human gastrointestinal tract, and grain elemental speciation trends are critical.
Resumo:
The IQ-motif is an amphipathic, often positively charged, a-helical, calmodulin binding sequence found in a number of eukaryote signalling, transport and cytoskeletal proteins. They share common biophysical characteristics with established, cationic a-helical antimicrobial peptides, such as the human cathelicidin LL-37. Therefore, we tested eight peptides encoding the sequences of IQ-motifs derived from the human cytoskeletal scaffolding proteins IQGAP2 and IQGAP3. Some of these peptides were able to inhibit the growth of Escherichia coli and Staphylococcus aureus with minimal inhibitory concentrations (MIC) comparable to LL-37. In addition some IQ-motifs had activity against the fungus Candida albicans. This antimicrobial activity is combined with low haemolytic activity (comparable to, or lower than, that of LL-37). Those IQ-motifs with anti-microbial activity tended to be able to bind to lipopolysaccharide. Some of these were also able to permeabilise the cell membranes of both Gram positive and Gram negative bacteria. These results demonstrate that IQ-motifs are viable lead sequences for the identification and optimisation of novel anti-microbial peptides. Thus, further investigation of the anti-microbial properties of this diverse group of sequences is merited.
Resumo:
Previous findings on older adults' awareness of community support services (CSSs) have been inconsistent and marred by acquiescence or over-claiming bias. To address this issue, this study used a series of 12 vignettes to describe common situations faced by older adults for which CSSs might be appropriate. In telephone interviews, 1,152 adults aged 50 years and over were read a series of vignettes and asked if they were able to identify a community organization or agency that they may turn to in that situation. They were also asked about their most important sources of information about CSSs. The findings show that, using a vignette methodology, awareness of CSSs is much lower than previously thought. The most important sources of information about CSSs included information and referral sources, the telephone book, doctors' offices, and word of mouth.
Resumo:
The purpose of this article is to determine whether middle-aged and older adults would identify community support services (CSSs) as a source of assistance for difficulties with the instrumental activities of daily living (IADLs). Furthermore, we determine factors related to the identification of home health and CSSs. Telephone interviews were conducted with 768 adults aged 50 and older. Respondents were presented with a vignette describing a situation where loss of independence is threatened. They were asked what they would do in that situation. Although less than 20% mentioned CSSs, nearly 50% mentioned either a home health or CSS. Findings suggest those less likely to mention a home health or CSS include men, older adults, and the foreign born. In addition, those with less education, functional health limitations, no social support, and a lack of knowledge of where to find information about CSSs mentioned home health or CSSs less often. © The Author(s) 2010.
Resumo:
We present empirical evidence about the properties of economic sentiment cycle synchronization for Germany, France and the UK and compare them with the `crisis' countries Italy, Spain, Portugal and Greece. Instead of using output data we prefer to focus on the economic sentiment indicator (ESI), a forward-looking, survey-based variable consistently available from 1985. The cyclical nature of the ESI allows us to analyze the presence or not of synchronicity among country pairs before and after the onset of the financial crisis. Our results show that ESI movements were mostly synchronous before 2008 but they exhibit a breakdown after 2008, with this feature being more prominent in Greece. We also find that, after the political manoeuvring of the past two years, a cycle re-integration or re-synchronization is on the way. An analysis of the evolution of the synchronicity measures indicates that they can potentially be used to identify sudden phase breaks in ESI co-movement and they can offer a signal as to when the EU economies are getting “in” or “out of sync”.