Determination of the a0-a2 pion scattering length from K->pi+ pi0 pi0 decay

We present a new method for the determination of the pion-pion scattering lenght combination a0-a2, based on the study of the pi0-pi0 spectrum in K->pi+ pi0 pi0 in the vicinity of the pi+ pi- threshold. The method requires a minimum of theoretical input, and is potentially very accurate.Comment: 8 pages, 2 figures -- corrected two typo

Not empty vessels: New Zealand pre-service additional language teacher identity.

Researchers have identified the importance of understanding language teacher identity in order to understand more about language teacher education (Johnston, Pawan, & Mahan-Taylor, 2005; Varghese, Morgan, Johnston, & Johnson, 2005). The role of previous experience in shaping language teacher identity and beliefs and practices has been commented on by many writers (e.g., Crandall, 2000; Freeman & Johnson, 1998). This paper reports on themes from semi-structured interviews conducted individually with four pre-service teachers of additional languages in the first stage of a longitudinal study of an Additional Language Teacher Education (ALTE) paper in a New Zealand tertiary institution. Results show that prior experience was pivotal to their conceptions of language teacher identity both prior to and after completion of the ALTE paper. The potential role of the ALTE paper in creating a wider net for students' experiences which could be drawn upon and incorporated into their conception of language teacher identity is discussed

The new journeyman: The role of an expert learner in eliciting and transmitting skilled knowledge

This paper presents interim research findings of a project which seeks to elicit the skilled knowledge of master craftsmen through use of an expert learner (Horne) acting as intermediary between the craftsmen and a designer (Wood) creating a multimedia resource to support those wishing to learn the skill. It builds on previous research that evolved a set of principles for the design of multimedia learning materials (Wood & Rust 2003) and moved on to develop techniques for elicitation of expert knowledge from craft masters (Wood 2006). The skills involved in undertaking such craft practice involve a high degree of tacit knowledge which is internalised and frequently difficult for the craft expert to articulate. The expert learner has the ability to learn new skills with minimal instruction then articulate those skills before they become too internalised. The role of designer is to assist with this articulation and develop interpretation suitable for transmitting the knowledge to novice learners. This research focuses on the skills of traditional custom knife makers in Sheffield; Horne has worked alongside two traditional craftsmen, video recorded by Wood. Together they have collaborated to analyse the recordings and develop learning materials to disseminate the craft skill. These are currently being developed and tested using a small group of learners with some one-to-one teaching followed by self-directed development work using an on-line resource. The main finding for this stage of the research was that, as Horne had relatively recently acquired this knowledge, it had not become too internalised and she was able to rapidly adapt her understanding of it to improve transmission to the learners in a manner that had not been demonstrated by more experienced craft practitioners. The interactions between Horne and the learners were mediated by Wood, facilitating reciprocal reflection between the them and designing ‘bridges’ to help transmit the knowledge to future generations of learners. Keywords: Multimedia Design; On-Line Learning; Tacit Knowledge; Craft Skills; Knowledge Elicitation</p

On existence and phase separation of solitary waves for nonlinear Schr\"odinger systems modelling simultaneous cooperation and competition

We study the existence of positive bound states for the nonlinear elliptic system $$\begin{cases} - \Delta u_i + \lambda_i u_i = \sum_{j=1}^d \beta_{ij} u_j^2 u_i & \text{in $\Omega$} \\ u_1 =\cdots = u_d=0 & \text{on $\partial \Omega$}, \end{cases}$$ where $d \ge 2$, $\beta_{ij}= \beta_{ji}$, $\beta_{ii},\lambda_i >0$, and $\Omega$ is either a bounded domain of $\mathbb{R}^N$, or $\Omega=\mathbb{R}^N$, with $N \le 3$. In light of its applicability in several physical contexts, the problem has been intensively studied in recent years, and several results concerning existence, multiplicity and qualitative properties of the solutions are available if either $\beta_{ij}\le 0$ for every $i \neq j$, or $\beta_{ij}>0$ for every $i \neq j$ and some additional assumptions are satisfied. On the other hand, only very partial results are known in the case of \emph{simultaneous cooperation and competition}, that is, when there exist two pairs $(i_1,j_1)$ and $(i_2,j_2)$ such that $i_1 \neq j_1$, $i_2 \neq j_2$, $\beta_{i_1 j_1}>0$ and $\beta_{i_2,j_2}<0$. In this setting, we provide sufficient conditions on the coupling parameters $\beta_{ij}$ in order to have a positive solution. Our first main results establishes the existence of solutions with at least $m$ positive components for every $m \le d$. Any such solution is a minimizer of the energy functional $J$ restricted on a \emph{Nehari-type manifold} $\mathcal{N}$. By means of level estimates on the constrained second differential of $J$ on $\mathcal{N}$, we show that, under some additional assumptions, any such minimizer has all nontrivial components. In order to prove this second result, we analyse the phase separation phenomena which involve solutions of the system in a \emph{not completely competitive} framework.Comment: 27 pages, no figures, published online on Calc. Var. PD