7,176 research outputs found

    Effective risk governance for environmental policy making: a knowledge management perspective

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    Effective risk management within environmental policy making requires knowledge on natural, economic and social systems to be integrated; knowledge characterised by complexity, uncertainty and ambiguity. We describe a case study in a (UK) central government department exploring how risk governance supports and hinders this challenging integration of knowledge. Forty-five semi-structured interviews were completed over a two year period. We found that lateral knowledge transfer between teams working on different policy areas was widely viewed as a key source of knowledge. However, the process of lateral knowledge transfer was predominantly informal and unsupported by risk governance structures. We argue this made decision quality vulnerable to a loss of knowledge through staff turnover, and time and resource pressures. Our conclusion is that the predominant form of risk governance framework, with its focus on centralised decision-making and vertical knowledge transfer is insufficient to support risk-based, environmental policy making. We discuss how risk governance can better support environmental policy makers through systematic knowledge management practices

    Level densities and γ\gamma-strength functions in 148,149^{148,149}Sm

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    The level densities and γ\gamma-strength functions of the weakly deformed 148^{148}Sm and 149^{149}Sm nuclei have been extracted. The temperature versus excitation energy curve, derived within the framework of the micro canonical ensemble, shows structures, which we associate with the break up of Cooper pairs. The nuclear heat capacity is deduced within the framework of both the micro canonical and the canonical ensemble. We observe negative heat capacity in the micro canonical ensemble whereas the canonical heat capacity exhibits an S-shape as function of temperature, both signals of a phase transition. The structures in the γ\gamma-strength functions are discussed in terms of the pygmy resonance and the scissors mode built on exited states. The samarium results are compared with data for the well deformed 161,162^{161,162}Dy, 166,167^{166,167}Er and 171,172^{171,172}Yb isotopes and with data from (n,γ\gamma)-experiments and giant dipole resonance studies.Comment: 12 figure

    OPTIS - a satellite-based test of Special and General Relativity

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    A new satellite based test of Special and General Relativity is proposed. For the Michelson-Morley experiment we expect an improvement of at least three orders of magnitude, and for the Kennedy-Thorndike experiment an improvement of more than one order of magnitude. Furthermore, an improvement by two orders of the test of the universality of the gravitational red shift by comparison of an atomic clock with an optical clock is projected. The tests are based on ultrastable optical cavities, an atomic clock and a comb generator.Comment: To appear in Class. Quantum Gra

    Thermal and electromagnetic properties of 166-Er and 167-Er

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    The primary gamma-ray spectra of 166-Er and 167-Er are deduced from the (3-He,alpha gamma) and (3-He,3-He' gamma) reaction, respectively, enabling a simultaneous extraction of the level density and the gamma-ray strength function. Entropy, temperature and heat capacity are deduced from the level density within the micro-canonical and the canonical ensemble, displaying signals of a phase-like transition from the pair-correlated ground state to an uncorrelated state at Tc=0.5 MeV. The gamma-ray strength function displays a bump around E-gamma=3 MeV, interpreted as the pygmy resonance.Comment: 21 pages including 2 tables and 11 figure

    Enhanced Local Moment Formation in a Chiral Luttinger Liquid

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    We derive here a stability condition for a local moment in the presence of an interacting sea of conduction electrons. The conduction electrons are modeled as a Luttinger liquid in which chirality and spin are coupled. We show that an Anderson-U defect in such an interacting system can be transformed onto a nearly-Fermi liquid problem. We find that correlations among the conduction electrons stabilize the local moment phase. A Schrieffer-Wolff transformation is then performed which results in an anisotropic exchange interaction indicative of the Kondo effect in a Luttinger liquid. The ground-state properties of this model are then equivalent to those of the Kondo model in a Luttinger liquid.Comment: 11 pages, no figure

    Large enhancement of radiative strength for soft transisitons in the quasicontinuum

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    Radiative strength functions (RSFs) for the 56,57-Fe nuclei below the separation energy are obtained from the 57-Fe(3-He,alpha gamma)56-Fe and 57-Fe(3-He,3-He' gamma)57-Fe reactions, respectively. An enhancement of more than a factor of ten over common theoretical models of the soft (E_gamma ~< 2 MeV) RSF for transitions in the quasicontinuum (several MeV above the yrast line) is observed. Two-step cascade intensities with soft primary transitions from the 56-Fe(n,2gamma)57-Fe reaction confirm the enhancement.Comment: 4 pages including 3 figure

    Population of neutron unbound states via two-proton knockout reactions

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    The two-proton knockout reaction 9Be(26Ne,O2p) was used to explore excited unbound states of 23O and 24O. In 23O a state at an excitation energy of 2.79(13) MeV was observed. There was no conclusive evidence for the population of excited states in 24O.Comment: 6 pages, 3 figures, Proc. 9th Int. Spring Seminar on Nucl. Phys. Changing Facets of Nuclear Structure, May 20-34, 200
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