531 research outputs found

    Flux vector splitting of the inviscid equations with application to finite difference methods

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    The conservation-law form of the inviscid gasdynamic equations has the remarkable property that the nonlinear flux vectors are homogeneous functions of degree one. This property readily permits the splitting of flux vectors into subvectors by similarity transformations so that each subvector has associated with it a specified eigenvalue spectrum. As a consequence of flux vector splitting, new explicit and implicit dissipative finite-difference schemes are developed for first-order hyperbolic systems of equations. Appropriate one-sided spatial differences for each split flux vector are used throughout the computational field even if the flow is locally subsonic. The results of some preliminary numerical computations are included

    Simple and highly efficient BAC recombineering using galK selection

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    Recombineering allows DNA cloned in Escherichia coli to be modified via lambda (λ) Red-mediated homologous recombination, obviating the need for restriction enzymes and DNA ligases to modify DNA. Here, we describe the construction of three new recombineering strains (SW102, SW105 and SW106) that allow bacterial artificial chromosomes (BACs) to be modified using galK positive/negative selection. This two-step selection procedure allows DNA to be modified without introducing an unwanted selectable marker at the modification site. All three strains contain an otherwise complete galactose operon, except for a precise deletion of the galK gene, and a defective temperature-sensitive λ prophage that makes recombineering possible. SW105 and SW106 cells in addition carry l-arabinose-inducible Cre or Flp genes, respectively. The galK function can be selected both for and against. This feature greatly reduces the background seen in other negative-selection schemes, and galK selection is considerably more efficient than other related selection methods published. We also show how galK selection can be used to rapidly introduce point mutations, deletions and loxP sites into BAC DNA and thus facilitate functional studies of SNP and/or disease-causing point mutations, the identification of long-range regulatory elements and the construction of conditional targeting vectors

    Drawing a river:Utilizing the Power of Metaphors in Interviews With Children and Young People

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    In the field of qualitative health research on children, scholars have called for the inclusion of children’s perspectives. Still, health care research on children appears to be characterized by an exclusionary approach that stems from a conception of disability and sickness as equivalent to a lack of agency. This article responds to the call to include children’s perspectives. It presents the Double-view (Dovi)-river interview, which is a drawing- and metaphor-based interview method that enables ambiguous and multi-layered life course narratives. Based on two steps – (1) a life course interview conducted while drawing a river of the child’s life and (2) revisiting and unfolding the child’s stories – the method allows for an arts-based, joint exploration of life experiences. Inspired by childhood studies as well as a poststructuralist epistemology, the article discusses and proposes ways to challenge power relations between the adult interviewer and the child interviewee. It is argued that the method can also challenge the predominant deficit view and the dichotomous understanding of children’s experiences of their life and capabilities that characterize much health care practice and health research, by focusing both on challenges and opportunities. Doing so enables a more nuanced and appreciative approach to children. We draw on empirical examples from a study with children with disabilities. However, we suggest that the method’s potential for enabling articulation of the complex and ambiguous can inspire qualitative research and health care practice more broadly

    Conceptualisations of children’s wellbeing at school: the contribution of recognition theory

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    A large study in Australian schools aimed to elucidate understandings of ‘wellbeing’ and of factors in school life that contribute to it. Students and teachers understood wellbeing primarily, and holistically, in terms of interpersonal relationships, in contrast to policy documents which mainly focused on ‘problem areas’ such as mental health. The study also drew on recognition theory as developed by the social philosopher Axel Honneth. Results indicate that recognition theory may be useful in understanding wellbeing in schools, and that empirical research in schools may give rise to further questions regarding theory

    oHSV Genome Editing by Means of galK Recombineering

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    open8noThis work was supported by European Research Council (ERC) Advanced Grant number 340060, VII framework program to G. C.-F., by RFO (University of Bologna) to L.M. and T.G, and by Fondi Pallotti to T.G.Since the cloning of the herpes simplex virus (HSV) genome as BAC (bacterial artificial chromosome), the genetic engineering of the viral genome has become readily feasible. The advantage is that the modification of the animal virus genome is carried out in bacteria, with no replication or production of viral progeny, and is separated from the reconstitution or regeneration of the recombinant virus in mammalian cells. This allows an easy engineering of essential genes, as well. Many technologies have been developed for herpesvirus BAC engineering. In our hands the most powerful is galK recombineering that exploits a single marker (galK) for positive and negative selection and PCR amplicons for seamless modification in the desired genome locus. Here we describe the engineering of the HSV recombinant BAC 115 by the insertion of a heterologous cassette for the expression of murine interleukin 12 (mIL12) in the intergenic sequence between US1 and US2 ORFs.embargoed_20201017Laura Menotti, Valerio Leoni, Valentina Gatta, Biljana Petrovic, Andrea Vannini, Simona Pepe, Tatiana Gianni, Gabriella Campadelli-FiumeLaura Menotti, Valerio Leoni, Valentina Gatta, Biljana Petrovic, Andrea Vannini, Simona Pepe, Tatiana Gianni, Gabriella Campadelli-Fium
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