62 research outputs found

    Renormalization-group running of the cosmological constant and the fate of the universe

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    For a generic quantum field theory we study the role played by the renormalization-group (RG) running of the cosmological constant (CC) in determining the ultimate fate of the universe. We consider the running of the CC of generic origin (the vacuum energy of quantum fields and the potential energy of classical fields), with the RG scale proportional to the (total energy density)1/4\rm{)^{1/4}} as the most obvious identification. Starting from the present-era values for cosmological parameters we demonstrate how the running can easily provide a negative cosmological constant, thereby changing the fate of the universe, at the same time rendering compatibility with critical string theory. We also briefly discuss the recent past in our scenario.Comment: 9 pages, 7 figures, revtex4; version to appear in PR

    Magnetic Field Generation in Stars

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    Enormous progress has been made on observing stellar magnetism in stars from the main sequence through to compact objects. Recent data have thrown into sharper relief the vexed question of the origin of stellar magnetic fields, which remains one of the main unanswered questions in astrophysics. In this chapter we review recent work in this area of research. In particular, we look at the fossil field hypothesis which links magnetism in compact stars to magnetism in main sequence and pre-main sequence stars and we consider why its feasibility has now been questioned particularly in the context of highly magnetic white dwarfs. We also review the fossil versus dynamo debate in the context of neutron stars and the roles played by key physical processes such as buoyancy, helicity, and superfluid turbulence,in the generation and stability of neutron star fields. Independent information on the internal magnetic field of neutron stars will come from future gravitational wave detections. Thus we maybe at the dawn of a new era of exciting discoveries in compact star magnetism driven by the opening of a new, non-electromagnetic observational window. We also review recent advances in the theory and computation of magnetohydrodynamic turbulence as it applies to stellar magnetism and dynamo theory. These advances offer insight into the action of stellar dynamos as well as processes whichcontrol the diffusive magnetic flux transport in stars.Comment: 41 pages, 7 figures. Invited review chapter on on magnetic field generation in stars to appear in Space Science Reviews, Springe

    Prospective patterns of resilience and maladjustment during widowhood

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142762/1/Bonanno-Nesse-Resil_Maladj_Patterns-PsychAging-2004.pd

    Amputation trauma of the face : surgical techniques and microsurgical replantations

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    The reconstruction of facial parts after traumatic amputation is of special interest because of the psychological and functional implications such accidents have on the patient. Most amputations result from dog bites or knife wounds and are often sustained by children and young adults. The amputated part may be an anatomic structure of functional importance (e.g. , the lips) or a static structure of primarily aesthetic importance (e.g. , the ear or nose). Here, the Authors present results in 6 cases of facial amputation reconstructed using microsurgical replantation for upper lip amputation, with use of the facial artery musculomucosal flap to fill labial defects, and the Mladick method for ear replantatio
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