283,673 research outputs found

    Antisymmetry and channel coupling contributions to the absorption for p + alpha/d + 3He

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    To understand recently established empirical p + alpha potentials, RGM calculations followed by inversion are made to study contributions of the d + 3He reaction channels and deuteron distortion effects to the p + alpha potential. An equivalent study of the d + 3He potential is also presented. The contributions of exchange non-locality to the absorption are simulated by including an phenomenological imaginary potential in the RGM. These effects alone strongly influence the shape of the imaginary potentials for both p + alpha and d + 3He. The potentials local-equivalent to the fully antisymmetrised-coupled channels calculations have a significant parity-dependence in both real and imaginary components, which for p + alpha is qualitatively similar to that found empirically. The effects on the potentials of the further inclusion of deuteron distortion are also presented. The inclusion of a spin-orbit term in the RGM, adds additional terms to the phase-equivalent potential, most notably the comparatively large imaginary spin-orbit term found empirically.Comment: 17 pages, Latex, 8 postscript figs, submitted to Nucl. Phys.

    Determination of Li-6 -- He-4 interaction from multi-energy scattering data

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    We present the first successful potential model description of Li-6 -- He-4 scattering. The differential cross-sections for three energies and the vector analyzing powers for two energies were fitted by a single potential with energy dependent imaginary components. An essential ingredient is a set of Majorana terms in each component. The potential was determined using a recently developed direct data-to-potential inversion method which is a generalisation of the IP S-matrix-to-potential inversion algorithm. We discuss the problems related to this phenomenological approach, and discuss the relationship of our results to existing and future theories.Comment: 9 pages plain LaTeX, 6 postscript figue

    Three-manifolds, virtual homology, and group determinants

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    We apply representation theory to study the homology of equivariant Dehn-fillings of a given finite, regular cover of a compact 3-manifold with boundary a torus. This yields a polynomial which gives the rank of the part of the homology carried by the solid tori used for Dehn-filling. The polynomial is a symmetrized form of the group determinant studied by Frobenius and Dedekind. As a corollary every such hyperbolic 3-manifold has infinitely many virtually Haken Dehn-fillings.Comment: This is the version published by Geometry & Topology on 29 November 200

    The evaluation of manufacturing issues in the product development process

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    Many companies still do not achieve the success rates they desire with new product introductions to the market. A method has been developed to aid companies to self-evaluate their product development processes (PDP). The method meets an identified need for a non-prescriptive procedure to evaluate an existing or proposed PDP at a detailed level, both in the context of the company's own products, processes, procedures and markets, and in the context of accepted good practice. The specification and development of the process and facilities needed for the manufacture of a product are identified as fundamental generic issues within the PDP that must be handled effectively to achieve successful product outcomes. The paper describes the main constructs of the evaluation method in relation to manufacturing issues, and presents results and findings from trials conducted in industry. It is seen that great care is needed to ensure that company practitioners make objective assessments of the important factors. Further work is planned to develop the method as an interactive computer tool and to conduct more trials

    One parameter family of Compacton Solutions in a class of Generalized Korteweg-DeVries Equations

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    We study the generalized Korteweg-DeVries equations derivable from the Lagrangian: L(l,p)=(12φxφt(φx)ll(l1)+α(φx)p(φxx)2)dx, L(l,p) = \int \left( \frac{1}{2} \varphi_{x} \varphi_{t} - { {(\varphi_{x})^{l}} \over {l(l-1)}} + \alpha(\varphi_{x})^{p} (\varphi_{xx})^{2} \right) dx, where the usual fields u(x,t)u(x,t) of the generalized KdV equation are defined by u(x,t)=φx(x,t)u(x,t) = \varphi_{x}(x,t). For pp an arbitrary continuous parameter 0<p2,l=p+20< p \leq 2 ,l=p+2 we find compacton solutions to these equations which have the feature that their width is independent of the amplitude. This generalizes previous results which considered p=1,2p=1,2. For the exact compactons we find a relation between the energy, mass and velocity of the solitons. We show that this relationship can also be obtained using a variational method based on the principle of least action.Comment: Latex 4 pages and one figure available on reques

    Variational Method for Studying Solitons in the KdV equation

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    We use a class of trial wave functions which are generalizations of gaussians to study single soliton approximate analytic solutions to the KdV equations. The variational parameters obey a Hamiltonian dynamics obtained from the Principle of Least Action. We get extremely accurate approximate single soliton solutions including their time dependence using this method.Comment: 8 page

    Implementing a Community Bipolar Screening Questionnaire in VT

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    The National Institute of Mental Health estimates the number of adults with a diagnosed mental disorder is nearly 1 in 5, this equates to about 43 million Americans. The national shortage of psychiatrists has hit Vermont particularly hard. There has been both a lack of funding and a lack of psychiatrists. For example there is often a waiting line for acute level 1 beds at the Vermont Psychiatric Care Hospital since it opened after the flooding of the state hospital in 2011. In light of the shortage of resources and psychiatrists in Vermont it is important to maximize the limited time that family practitioners have with patients with mental illness. With regards to diagnosing bipolar spectrum disorder the best method is using the Mood Disorder Questionnaire (MDQ) which is a 17 question survey and practical for an outpatient setting. A study examining the validity of the MDQ found that it provided good sensitivity (0.73, 95% [CI]=0.65–0.81) without sacrificing specificity (0.90, 95% CI=0.84–0.96). Another study was conducted in a community setting and it was found that the MDQ had a sensitivity of 0.28 and a specificity of 0.97. The MDQ has been proven to be effective in a psychiatric outpatient setting and been proven to be less effective or limited in the outpatient setting. However we must weigh the risks and benefits. In a setting like Vermont, with restricted resources, limited inpatient beds, lack of psychiatrists and a population of individuals with undiagnosed bipolar spectrum disorder the MDQ can prove to be more useful than harmful and can aid in identifying patients who potentially have bipolar spectrum disorder.https://scholarworks.uvm.edu/fmclerk/1319/thumbnail.jp
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