45,942 research outputs found

    Perceived Family Life Quality in Junior Secondary School Students in Hong Kong

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    The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.The present longitudinal study examined perceived family functioning and related socio-demographic correlates from the perspective of adolescents in Hong Kong. Results showed that adolescent perceptions of family functioning based on different indicators gradually deteriorated over time. Regarding the socio-demographic correlates, (a) boys had more favourable perceived family functioning than did girls; (b) adolescents from non-intact families had poorer perceived family functioning than those from intact families; and (c) economically disadvantaged adolescents had poorer perceived family functioning than non-economically disadvantaged adolescents. Results also revealed that adolescents’ perceived family functioning was positively related to positive youth devel- opment. Analyses further indicated that perceived family functioning and positive youth development were concurrently and longitudinally related

    Supergravity with a Gravitino LSP

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    We investigate supergravity models in which the lightest supersymmetric particle (LSP) is a stable gravitino. We assume that the next-lightest supersymmetric particle (NLSP) freezes out with its thermal relic density before decaying to the gravitino at time t ~ 10^4 s - 10^8 s. In contrast to studies that assume a fixed gravitino relic density, the thermal relic density assumption implies upper, not lower, bounds on superpartner masses, with important implications for particle colliders. We consider slepton, sneutrino, and neutralino NLSPs, and determine what superpartner masses are viable in all of these cases, applying CMB and electromagnetic and hadronic BBN constraints to the leading two- and three-body NLSP decays. Hadronic constraints have been neglected previously, but we find that they provide the most stringent constraints in much of the natural parameter space. We then discuss the collider phenomenology of supergravity with a gravitino LSP. We find that colliders may provide important insights to clarify BBN and the thermal history of the Universe below temperatures around 10 GeV and may even provide precise measurements of the gravitino's mass and couplings.Comment: 24 pages, updated figures and minor changes, version to appear in Phys.Rev.

    SuperWIMP Cosmology and Collider Physics

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    Dark matter may be composed of superWIMPs, superweakly-interacting massive particles produced in the late decays of other particles. We focus here on the well-motivated supersymmetric example of gravitino LSPs. Gravitino superWIMPs share several virtues with the well-known case of neutralino dark matter: they are present in the same supersymmetric frameworks (supergravity with R-parity conservation) and naturally have the desired relic density. In contrast to neutralinos, however, gravitino superWIMPs are impossible to detect by conventional dark matter searches, may explain an existing discrepancy in Big Bang nucleosynthesis, predict observable distortions in the cosmic microwave background, and imply spectacular signals at future particle colliders.Comment: 12 pages, to appear in the proceedings of SUSY2004, the 12th International Conference on Supersymmetry and Unification of Fundamental Interactions, Tsukuba, Japan, 17-23 June 200

    Whole-brain patterns of 1H-magnetic resonance spectroscopy imaging in Alzheimer's disease and dementia with Lewy bodies

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    Acknowledgements We thank Craig Lambert for his help in processing the MRS data. The study was funded by the Sir Jules Thorn Charitable Trust (grant ref: 05/JTA) and was supported by the National Institute for Health Research (NIHR) Newcastle Biomedical Research Centre and the Biomedical Research Unit in Lewy Body Dementia based at Newcastle upon Tyne Hospitals National Health Service (NHS) Foundation Trust and Newcastle University and the NIHR Biomedical Research Centre and Biomedical Research Unit in Dementia based at Cambridge University Hospitals NHS Foundation Trust and the University of Cambridge.Peer reviewedPublisher PD

    Renormalization of the Sigma-Omega model within the framework of U(1) gauge symmetry

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    It is shown that the Sigma-Omega model which is widely used in the study of nuclear relativistic many-body problem can exactly be treated as an Abelian massive gauge field theory. The quantization of this theory can perfectly be performed by means of the general methods described in the quantum gauge field theory. Especially, the local U(1) gauge symmetry of the theory leads to a series of Ward-Takahashi identities satisfied by Green's functions and proper vertices. These identities form an uniquely correct basis for the renormalization of the theory. The renormalization is carried out in the mass-dependent momentum space subtraction scheme and by the renormalization group approach. With the aid of the renormalization boundary conditions, the solutions to the renormalization group equations are given in definite expressions without any ambiguity and renormalized S-matrix elememts are exactly formulated in forms as given in a series of tree diagrams provided that the physical parameters are replaced by the running ones. As an illustration of the renormalization procedure, the one-loop renormalization is concretely carried out and the results are given in rigorous forms which are suitable in the whole energy region. The effect of the one-loop renormalization is examined by the two-nucleon elastic scattering.Comment: 32 pages, 17 figure
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