221 research outputs found
Residents' perception of the social-cultural impacts of the 2008 Formula 1 Singtel Singapore Grand Prix
Inter-species horizontal transfer resulting in core-genome and niche-adaptive variation within Helicobacter pylori
Background
Horizontal gene transfer is central to evolution in most bacterial species. The detection of exchanged regions is often based upon analysis of compositional characteristics and their comparison to the organism as a whole. In this study we describe a new methodology combining aspects of established signature analysis with textual analysis approaches. This approach has been used to analyze the two available genome sequences of H. pylori.
Results
This gene-by-gene analysis reveals a wide range of genes related to both virulence behaviour and the strain differences that have been relatively recently acquired from other sequence backgrounds. These frequently involve single genes or small numbers of genes that are not associated with transposases or bacteriophage genes, nor with inverted repeats typically used as markers for horizontal transfer. In addition, clear examples of horizontal exchange in genes associated with 'core' metabolic functions were identified, supported by differences between the sequenced strains, including: ftsK, xerD and polA. In some cases it was possible to determine which strain represented the 'parent' and 'altered' states for insertion-deletion events. Different signature component lengths showed different sensitivities for the detection of some horizontally transferred genes, which may reflect different amelioration rates of sequence components.
Conclusion
New implementations of signature analysis that can be applied on a gene-by-gene basis for the identification of horizontally acquired sequences are described. These findings highlight the central role of the availability of homologous substrates in evolution mediated by horizontal exchange, and suggest that some components of the supposedly stable 'core genome' may actually be favoured targets for integration of foreign sequences because of their degree of conservation
Lesbians and gay men’s holiday motivations, perceptions and constraints: a case study of cruise vacation choice
Assessing the transition towards battery electric vehicles:a Multi-Level Perspective on drivers of, and barriers to, take up.
The Multi-Level Perspective (MLP) framework on transitions is used to interpret European electric vehicle take up and auto mobility transition. It finds that environmental and energy security pressures have created a favourable landscape ‘push’ for Battery Electric Vehicles (BEVs) that in turn has encouraged and facilitated serious commitment from some manufacturers. Yet BEVs, as a niche product seeking to disrupt an entrenched and established regime, face significant multi-level forces acting as barriers against such a transition, which the paper explores. This combination of factors creates a situation where BEV market penetration remains far below the level required for mass market transition. For BEVs to ‘cross the chasm’ and gain an established foothold in the market and hence significantly disrupt the regime, more holistic and effective solutions are required. It is argued that, so far, this has yet to be fully taken on board by policy makers
The importance of tourism motivations among sport event volunteers at the 2007 World Artistic Gymnastics Championships, Stuttgart, Germany
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