71 research outputs found
Collective Quantisation of a Gravitating Skyrmion
Collective quantisation of a B=1 gravitating skyrmion is described. The
rotational and isorotational modes are quantised in the same manner as the
skyrmion without gravity. It is shown in this paper how the static properties
of nucleons such as masses, charge densities, magnetic moments are modified by
the gravitational interaction.Comment: 10 pages, 9 figures, minor corrections, published versio
Regular and Black Hole Solutions in the Einstein-Skyrme Theory with Negative Cosmological Constant
We study spherically symmetric regular and black hole solutions in the
Einstein-Skyrme theory with a negative cosmological constant. The Skyrme field
configuration depends on the value of the cosmological constant in a similar
manner to effectively varying the gravitational constant. We find the maximum
value of the cosmological constant above which there exists no solution. The
properties of the solutions are discussed in comparison with the asymptotically
flat solutions. The stability is investigated in detail by solving the linearly
perturbed equation numerically. We show that there exists a critical value of
the cosmological constant above which the solution in the branch representing
unstable configuration in the asymptotically flat spacetime turns to be
linearly stable.Comment: 10 pages, 9 figures, comments and one reference added, to appear in
Class.Quant.Gra
Soliton solutions in an effective action for SU(2) Yang-Mills theory: including effects of higher-derivative term
The Skyrme-Faddeev-Niemi (SFN) model which is an O(3) model in three
dimensional space upto fourth-order in the first derivative is regarded as a
low-energy effective theory of SU(2) Yang-Mills theory. One can show from the
Wilsonian renormalization group argument that the effective action of
Yang-Mills theory recovers the SFN in the infrared region. However, the thoery
contains an additional fourth-order term which destabilizes the soliton
solution. In this paper, we derive the second derivative term perturbatively
and show that the SFN model with the second derivative term possesses soliton
solutions.Comment: 7 pages, 3 figure
B=3 Tetrahedrally Symmetric Solitons in the Chiral Quark Soliton Model
In this paper, B=3 soliton solutions with tetrahedral symmetry are obtained
numerically in the chiral quark soliton model using the rational map ansatz.
The solution exhibits a triply degenerate bound spectrum of the quark orbits in
the background of tetrahedrally symmetric pion field configuration. The
corresponding baryon density is tetrahedral in shape. Our numerical technique
is independent on the baryon number and its application to is
straightforward.Comment: 4 pages, 3 figure
Classical Yang-Mills Black hole hair in anti-de Sitter space
The properties of hairy black holes in EinsteinâYangâMills (EYM) theory are reviewed, focusing on spherically symmetric solutions. In particular, in asymptotically anti-de Sitter space (adS) stable black hole hair is known to exist for frak su(2) EYM. We review recent work in which it is shown that stable hair also exists in frak su(N) EYM for arbitrary N, so that there is no upper limit on how much stable hair a black hole in adS can possess
Localization of macrophage migration inhibitory factor (MIF) to secretory granules within the corticotrophic and thyrotrophic cells of the pituitary gland
BACKGROUND: Macrophage migration inhibitory factor (MIF) was one of the first lymphokine activities to be discovered and was described almost 30 years ago to be a soluble factor(s) produced by activated T lymphocytes. In more recent studies, MIF has been "rediscovered" to be an abundant, pre-formed constituent of the anterior pituitary gland and the macrophage, and to be a critical component in the host response to septic shock. Pituitary-derived MIF enters the circulation after infectious or stressful stimuli and appears to act to counterregulate glucocorticoid suppression of cytokine production. MATERIALS AND METHODS: Immunoelectron microscopy utilizing a combination of anti-MIF and anti-pituitary hormone-specific antibodies was used to study the ultrastructural localization of MIF within the anterior pituitary gland. Pituitaries were obtained from resting, unstimulated mice and from mice 16 hr after endotoxin administration. The release of MIF also was investigated in vitro by examining the effect of corticotropin-releasing hormone (CRH_ on the AtT-20, corticotrophic cell line. RESULTS: MIF localizes to granules present exclusively in ACTH and TSH secreting cells. Within each cell type, a subset of granules was found to contain both MIF and ACTH, or MIF and TSH. The pituitary content of MIF-containing granules decreased significantly after experimentally induced endotoxemia. In seven pituitaries examined 16 hr after LPS injection, the number of MIF-positive granules diminished by 38% in corticotrophic cells and by 48% in thyrotrophic cells when compared with controls (p < 0.05). CRH was observed to be a potent MIF secretagogue in vitro, inducing the release of MIF from corticotrophic cells at concentrations lower than that required for ACTH release. CONCLUSION: These data provide ultrastructural information that identify MIF to be a novel anterior pituitary hormone, support earlier studies showing a time-dependent release of pituitary MIF during endotoxemia, and suggest an important, systemic role for MIF in the stress response to infection and other stimuli
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