7 research outputs found
Oro-facial aspects of leprosy : report of two cases with literature review
Leprosy is a chronic infectious disease affecting primarily the skin, peripheral nerves, respiratory system and the eyes. Leprosy induces various types of clinical presentation affecting the patient´s immune response. Cellmediated immunity is considered to be the crucial defence against the disease and the magnitude of this immunity defines the extent of the disease. The article presents two case reports of manifestations of leprosy in the oro-facial region, with a brief review of various other important oro-facial manifestations of leprosy. The first report deals with granulomatous nodules in the palate while the second report presents bilateral facial palsy in leprosy patients. Both the reports gain importance due to rare oral manifestation in a borderline leprosy patient in the first case, while the second case presents a rare bilateral Bell´s sign. The role of the dental profession and especially the Oral Medicine specialist is of great importance in early diagnosis of oral lesions
Interactions of Non-Abelian Global Strings
Non-Abelian global strings are expected to form during the chiral phase
transition. They have orientational zero modes in the internal space,
associated with the vector-like symmetry SU(N)_{L+R} broken in the presence of
strings. The interaction among two parallel non-Abelian global strings is
derived for general relative orientational zero modes, giving a non-Abelian
generalization of the Magnus force. It is shown that when the orientations of
the strings are the same, the repulsive force reaches the maximum, whereas when
the relative orientation becomes the maximum, no force exists between the
strings. For the Abelian case we find a finite volume correction to the known
result. The marginal instability of the previously known Abelian eta' strings
is discussed.Comment: 12 pages, 2 figures, a brief discussion on stability added, published
versio
Boundary degrees of freedom in fractional quantum Hall effect: Excitations on common boundary of two samples
Using the Carlip's method we have derived the boundary action for the fermion
Chern-Simons theory of quantum Hall effects on a planar region with a boundary.
We have computed both the bulk and edge responses of currents to the external
electric field. From this we obtain the well-known anomaly relation and the
boundary Hall current without introducing any ad hoc assumptions such as the
chirality condition. In addition, the edge current on the common boundary of
two samples is found to be proportional to the difference between Chern-Simons
coupling strengths.Comment: 20 pages, uses revte
Non-Abelian Global Vortices
We study topologically stable non-Abelian global vortices in the U(N) linear
sigma model. The profile functions of the solutions are numerically obtained.
We investigate the behaviour of vortices in two limits in which masses of
traceless or trace parts of massive bosons are much larger than the others. In
the limit that the traceless parts are much heavier, we find a somewhat bizarre
vortex solution carrying a non-integer U(1) winding number 1/\sqrt{N} which is
irrational in general.Comment: 28 pages, 6 figure
Bulk Versus Edge in the Quantum Hall Effect
The manifestation of the bulk quantum Hall effect on edge is the chiral
anomaly. The chiral anomaly {\it is} the underlying principle of the ``edge
approach'' of quantum Hall effect. In that approach, \sxy should not be taken
as the conductance derived from the space-local current-current correlation
function of the pure one-dimensional edge problem.Comment: 4 pages, RevTex, 1 postscript figur
Optimised Dirac Operators on the Lattice: Construction, Properties and Applications
We review a number of topics related to block variable renormalisation group
transformations of quantum fields on the lattice, and to the emerging perfect
lattice actions. We first illustrate this procedure by considering scalar
fields. Then we proceed to lattice fermions, where we discuss perfect actions
for free fields, for the Gross-Neveu model and for a supersymmetric spin model.
We also consider the extension to perfect lattice perturbation theory, in
particular regarding the axial anomaly and the quark gluon vertex function.
Next we deal with properties and applications of truncated perfect fermions,
and their chiral correction by means of the overlap formula. This yields a
formulation of lattice fermions, which combines exact chiral symmetry with an
optimisation of further essential properties. We summarise simulation results
for these so-called overlap-hypercube fermions in the two-flavour Schwinger
model and in quenched QCD. In the latter framework we establish a link to
Chiral Perturbation Theory, both, in the p-regime and in the epsilon-regime. In
particular we present an evaluation of the leading Low Energy Constants of the
chiral Lagrangian - the chiral condensate and the pion decay constant - from
QCD simulations with extremely light quarks.Comment: published version (plus slight extension), 120 pages, 41 figure