574 research outputs found

    Sustainable Development Stakeholder Networks for Organisational Change in Higher Education Institutions: A Case Study from the UK

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    Progressing towards sustainable development remains a key global challenge. And yet, the various interpretations of the concept of sustainable development and the questions it raises about economic growth make its implementation difficult. Higher education institutions may help to overcome these difficulties by developing new processes of change. However, to achieve this they need to integrate sustainable development in all their areas of activity. The aim of this paper was to develop new insights into organisational change processes in universities relating to sustainable development. Contributing to this aim, this paper reports on a case study of United Kingdom higher education drawing on findings and conclusions from a survey of their policy frameworks relating to sustainable development. The method comprised a critical policy analysis in order to identify, differentiate and categorise stakeholder interactions. The data generated comprised the range of higher education stakeholders and the network of interactions that they formed. Theoretical insights from social network analysis, stakeholder theory and the normative business model were used to find opportunities to address the difficulties in the implementation of sustainable development. Results suggested that the existing networks identified in the policy frameworks may not support the effective integration of sustainable development in higher education. Low-density of the national networks; the lack of a clear governance vocabulary for national policy frameworks; and the lack of explicit funding flows between organisations all pose problems for organisational change towards sustainable development in higher education

    Warm strange hadronic matter in an effective model with a weak Y-Y interaction

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    An effective model is used to study the equation of state of warm strange hadronic matter with nucleons, Lambda-hyperons, Xi-hyperons, sigmastar and phi. In the calculation, a newest weak Y-Y interaction deduced from the recent observation of a He double hypernucleus is adopted. Employing this effective model, the results with strong Y-Y interaction and weak Y-Y interaction are compared.Comment: 9 pages, 9 figure

    What Does Free Space Lambda-Lambda Interaction Predict for Lambda-Lambda Hypernuclei?

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    Data on Lambda-Lambda hypernuclei provide a unique method to learn details on the strangeness S =-2 sector of the baryon-baryon interaction. From the free space Bonn-Julich potentials, determined from data on baryon-baryon scattering in the S=0,-1 channels, we construct an interaction in the S =-2 sector to describe the experimentally known Lambda-Lambda hypernuclei. After including short--range (Jastrow) and RPA correlations, we find masses for these Lambda-Lambda hypernuclei in a reasonable agreement with data, taking into account theoretical and experimental uncertainties. Thus, we provide a natural extension, at low energies, of the Bonn-Julich OBE potentials to the S =-2 channel.Comment: 4 pages, 2 figures, revtex4 style. Minor changes in conclusions. References updated. Accepted in Phys. Rev. Let

    Nuclear and nucleon transitions of the H di-baryon

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    We consider 3 types of processes pertinent to the phenomenology of an H di-baryon: conversion of two Λ\Lambda's in a doubly-strange hypernucleus to an H, decay of the H to two baryons, and -- if the H is light enough -- conversion of two nucleons in a nucleus to an H. We compute the spatial wavefunction overlap using the Isgur-Karl and Bethe-Goldstone wavefunctions, and treat the weak interactions phenomenologically. The observation of Λ\Lambda decays from doubly-strange hypernuclei puts a constraint on the H wavefunction which is plausibly satisfied. In this case the H is very long-lived as we calculate. An absolutely stable H is not excluded at present. SuperK can provide valuable limits

    Neutron Star Constraints on the H Dibaryon

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    We study the influence of a possible H dibaryon condensate on the equation of state and the overall properties of neutron stars whose population otherwise contains nucleons and hyperons. In particular, we are interested in the question of whether neutron stars and their masses can be used to say anything about the existence and properties of the H dibaryon. We find that the equation of state is softened by the appearance of a dibaryon condensate and can result in a mass plateau for neutron stars. If the limiting neutron star mass is about that of the Hulse-Taylor pulsar a condensate of H dibaryons of vacuum mass 2.2 GeV and a moderately attractive potential in the medium could not be ruled out. On the other hand, if the medium potential were even moderately repulsive, the H, would not likely exist in neutron stars. If neutron stars of about 1.6 solar mass were known to exist, attractive medium effects for the H could be ruled out. Certain ranges of dibaryon mass and potential can be excluded by the mass of the Hulse-Taylor pulsar which we illustrate graphically.Comment: Revised by the addition of a figure showing the region of dibaryon mass and potential excluded by the Hulse-Taylor pulsar. 18 pages, 11 figures, latex (submitted to Phys. Rev. C

    Novel Weak Decays in Doubly Strange Systems

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    The strangeness-changing (ΔS=1\Delta S = 1) weak baryon-baryon interaction is studied through the nonmesonic weak decay of double-Λ\Lambda hypernuclei. Besides the usual nucleon-induced decay ΛNNN\Lambda N \to N N we discuss novel hyperon-induced decay modes ΛΛΛN\Lambda \Lambda \to \Lambda N and ΛΛΣN\Lambda \Lambda \to \Sigma N. These reactions provide unique access to the exotic ΛΛ\Lambda \LambdaK and ΛΣ\Lambda \SigmaK vertices which place new constraints on Chiral Pertubation Theory (χ\chiPT) in the weak SU(3) sector. Within a meson-exchange framework, we use the pseudoscalar π,η,K\pi,\eta,K octet for the long-range part while parametrizing the short-range part through the vector mesons ρ,ω,K\rho, \omega, K^*. Realistic baryon-baryon forces for the S=0,1S=0,-1 and -2 sectors account for the strong interaction in the initial and final states. For ΛΛ6^6_{\Lambda \Lambda}He the new hyperon-induced decay modes account for up to 4% of the total nonmesonic decay rate. Predictions are made for all possible nonmesonic decay modes.Comment: 19 pages, 2 ps figures, 9 table

    Arctic system on trajectory to new state

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    The Arctic system is moving toward a new state that falls outside the envelope of glacial-interglacial fluctuations that prevailed during recent Earth history. This future Arctic is likely to have dramatically less permanent ice than exists at present. At the present rate of change, a summer ice-free Arctic Ocean within a century is a real possibility, a state not witnessed for at least a million years. The change appears to be driven largely by feedback-enhanced global climate warming, and there seem to be few, if any processes or feedbacks within the Arctic system that are capable of altering the trajectory toward this “super interglacial” state

    Dihyperon in Chiral Colour Dielectric Model

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    The mass of dihyperon with spin, parity Jπ=0+J^{\pi}=0^{+} and isospin I=0I = 0 is calculated in the framework of Chiral colour dielectric model. The wave function of the dihyperon is expressed as a product of two colour-singlet baryon clusters. Thus the quark wave functions within the cluster are antisymmetric. Appropriate operators are then used to antisymmetrize inter-cluster quark wave functions. The radial part of the quark wavefunctions are obtained by solving the the quark and dielectric field equations of motion obtained in the Colour dielectric model. The mass of the dihyperon is computed by including the colour magnetic energy as well as the energy due to meson interaction. The recoil correction to the dihyperon mass is incorporated by Peierls-Yoccoz technique. We find that the mass of the dihyperon is smaller than the ΛΛ\Lambda-\Lambda threshold by over 100 MeV. The implications of our results on the present day relativistic heavy ion experiments is discussed.Comment: LaTeX, 13 page

    Nuclei, Superheavy Nuclei and Hypermatter in a chiral SU(3)-Modell

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    A model based on chiral SU(3)-symmetry in nonlinear realisation is used for the investigation of nuclei, superheavy nuclei, hypernuclei and multistrange nuclear objects (so called MEMOs). The model works very well in the case of nuclei and hypernuclei with one Lambda-particle and rules out MEMOs. Basic observables which are known for nuclei and hypernuclei are reproduced satisfactorily. The model predicts Z=120 and N=172, 184 and 198 as the next shell closures in the region of superheavy nuclei. The calculations have been performed in self-consistent relativistic mean field approximation assuming spherical symmetry. The parameters were adapted to known nuclei.Comment: 19 pages, 11 figure

    Detectability of Strange Matter in Heavy Ion Experiments

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    We discuss the properties of two distinct forms of hypothetical strange matter, small lumps of strange quark matter (strangelets) and of hyperon matter (metastable exotic multihypernuclear objects: MEMOs), with special emphasis on their relevance for present and future heavy ion experiments. The masses of small strangelets up to A = 40 are calculated using the MIT bag model with shell mode filling for various bag parameters. The strangelets are checked for possible strong and weak hadronic decays, also taking into account multiple hadron decays. It is found that strangelets which are stable against strong decay are most likely highly negative charged, contrary to previous findings. Strangelets can be stable against weak hadronic decay but their masses and charges are still rather high. This has serious impact on the present high sensitivity searches in heavy ion experiments at the AGS and CERN facilities. On the other hand, highly charged MEMOs are predicted on the basis of an extended relativistic mean-field model. Those objects could be detected in future experiments searching for short-lived, rare composites. It is demonstrated that future experiments can be sensitive to a much wider variety of strangelets.Comment: 26 pages, 5 figures, uses RevTeX and epsf.st
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