152 research outputs found
Test de activación de basófilos en el diagnóstico de alergia a medicamentos
In this paper we study the reliability of the basophil activation test (BAT) in the "in-vitro" diagnosis of allergy to betalactams and to metamizol, and the sensitivity and specificity of the technique are analyzed. To this end, we studied 58 patients allergic to betalactam antibiotics with a positive cutaneous test facing any derivative of penicillin and 30 healthy controls who tolerated betalactams, and 26 patients allergic to metamizol with an immediate reaction and 30 healthy controls who tolerated the medicine. Sensitivity to BAT in allergy to betalactams was 52.8%, and specificity was 92.6%. For metamizol, sensitivity was 42.3% and specificity was 100%. The positive predictive value of BAT in allergy to betalactams was 18.9% and the negative predictive value was 98.4%. For metamizol, the positive predictive value of the technique was 100% and the negative predictive value was 99.4%. The joint use of BAT and CAP (specific IgE) makes it possible to diagnose some 65% of patients allergic to betalactams. The combined use of cutaneous tests and BAT in allergy to metamizol detects 70% of the cases. BAT is a useful, non-invasive technique in the "in-vitro" diagnosis of allergy to betalactams and metamizol
Aharonov-Casher effect for spin one particles in a noncommutative space
In this work the Aharonov-Casher (AC) phase is calculated for spin one
particles in a noncommutative space. The AC phase has previously been
calculated from the Dirac equation in a noncommutative space using a gauge-like
technique [17]. In the spin-one, we use kemmer equation to calculate the phase
in a similar manner. It is shown that the holonomy receives non-trivial
kinematical corrections. By comparing the new result with the already known
spin 1/2 case, one may conjecture a generalized formula for the corrections to
holonomy for higher spins.Comment: 9 page
Non-commutative Oscillators and the commutative limit
It is shown in first order perturbation theory that anharmonic oscillators in
non-commutative space behave smoothly in the commutative limit just as harmonic
oscillators do. The non-commutativity provides a method for converting a
problem in degenerate perturbation theory to a non-degenerate problem.Comment: Latex, 6 pages, Minor changes and references adde
Anomalies in Noncommutative Dipole Field Theories
We study chiral symmetries of fermionic non commutative dipole theories. By
using Fujikawa's approach we obtain explicit expressions of the anomalies for
Dirac and chiral fermions in 2 and 4 dimensions.Comment: 11pages, latex file. Comments adde
Noncommutative massive Thirring model in three-dimensional spacetime
We evaluate the noncommutative Chern-Simons action induced by fermions
interacting with an Abelian gauge field in a noncommutative massive Thirring
model in (2+1)-dimensional spacetime. This calculation is performed in the
Dirac and Majorana representations. We observe that in Majorana representation
when goes to zero we do not have induced Chern-Simons term in the
dimensional regularization scheme.Comment: Accepted to Phys. Rev. D; 9 pages, Revtex4, no figures, references
added, minor improvements, Eq.31 correcte
Noncommutative Quantum Mechanics and Seiberg-Witten Map
In order to overcome ambiguity problem on identification of mathematical
objects in noncommutative theory with physical observables, quantum mechanical
system coupled to the NC U(1) gauge field in the noncommutative space is
reformulated by making use of the unitarized Seiberg-Witten map, and applied to
the Aharonov-Bohm and Hall effects of the NC U(1) gauge field. Retaining terms
only up to linear order in the NC parameter \theta, we find that the AB
topological phase and the Hall conductivity have both the same formulas as
those of the ordinary commutative space with no \theta-dependence.Comment: 7 pages, no figures, uses revtex4; 8 pages, conclusion changed,
Appendix adde
On the Meaning of the String-Inspired Noncommutativity and its Implications
We propose an alternative interpretation for the meaning of noncommutativity
of the string-inspired field theories and quantum mechanics. Arguments are
presented to show that the noncommutativity generated in the stringy context
should be assumed to be only between the particle coordinate observables, and
not of the spacetime coordinates. Some implications of this fact for
noncomutative field theories and quantum mechanics are discussed. In
particular, a consistent interpretation is given for the wavefunction in
quantum mechanics. An analysis of the noncommutative theories in the
Schr\"odinger formulation is performed employing a generalized quantum
Hamilton-Jacobi formalism. A formal structure for noncommutative quantum
mechanics, richer than the one of noncommutative quantum field theory, comes
out. Conditions for the classical and commutative limits of these theories have
also been determined and applied in some examples.Comment: References, comments, and footnotes are included; some changes in
section
Landau Analog Levels for Dipoles in the Noncommutative Space and Phase Space
In the present contribution we investigate the Landau analog energy
quantization for neutral particles, that possesses a nonzero permanent magnetic
and electric dipole moments, in the presence of an homogeneous electric and
magnetic external fields in the context of the noncommutative quantum
mechanics. Also, we analyze the Landau--Aharonov--Casher and
Landau--He--McKellar--Wilkens quantization due to noncommutative quantum
dynamics of magnetic and electric dipoles in the presence of an external
electric and magnetic fields and the energy spectrum and the eigenfunctions are
obtained. Furthermore, we have analyzed Landau quantization analogs in the
noncommutative phase space, and we obtain also the energy spectrum and the
eigenfunctions in this context.Comment: 20 pages, references adde
Noncommutative quantum mechanics and Bohm's ontological interpretation
We carry out an investigation into the possibility of developing a Bohmian
interpretation based on the continuous motion of point particles for
noncommutative quantum mechanics. The conditions for such an interpretation to
be consistent are determined, and the implications of its adoption for
noncommutativity are discussed. A Bohmian analysis of the noncommutative
harmonic oscillator is carried out in detail. By studying the particle motion
in the oscillator orbits, we show that small-scale physics can have influence
at large scales, something similar to the IR-UV mixing
Large-scale magnetic fields from inflation due to a -even Chern-Simons-like term with Kalb-Ramond and scalar fields
We investigate the generation of large-scale magnetic fields due to the
breaking of the conformal invariance in the electromagnetic field through the
-even dimension-six Chern-Simons-like effective interaction with a fermion
current by taking account of the dynamical Kalb-Ramond and scalar fields in
inflationary cosmology. It is explicitly demonstrated that the magnetic fields
on 1Mpc scale with the field strength of G at the present time
can be induced.Comment: 18 pages, 6 figures, version accepted for publication in Eur. Phys.
J.
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