On the aether-like Lorentz-breaking actions (2009)
Gomes, M., Nascimento, J. R., Petrov, A. Yu., Da Silva, A. J.
We demonstrate the generation of the CPT-even, aether-like Lorentz-breaking actions for the scalar and electromagnetic fields via their appropriate Lorentz-breaking coupling to spinor fields in...
Free energy of Lorentz-violating QED at high temperature (2009)
Gomes, M., Mariz, T., Nascimento, J. R., Petrov, A. Yu., Santos, A. F., Da Silva, A. J.
In this paper we study the one- and two-loop contribution to the free energy in QED with the Lorentz symmetry breaking introduced via constant CPT-even Lorentz-breaking parameters at the high...
Dynamical noncommutativity (2009)
Gomes, M., Kupriyanov, V. G., Da Silva, A. J.
The model of dynamical noncommutativity is proposed. The system consists of two interrelated parts. The first of them describes the physical degrees of freedom with coordinates q^1, q^2, the second...
On the effective potential in higher-derivative superfield theories (2009)
Gomes, M., Nascimento, J. R., Petrov, A. Yu., Da Silva, A. J.
We study the one-loop quantum corrections for higher-derivative superfield theories, generalizing the approach for calculating the superfield effective potential. In particular, we calculate the...
Position-dependent noncommutativity in quantum mechanics (2009)
The model of the position-dependent noncommutativety in quantum mechanics is proposed. We start with a given commutation relations between the operators of coordinates [x^{i},x^{j}]=\omega^{ij}(x),...
On the superfield effective potential in three dimensions (2009)
Ferrari, A. F., Gomes, M., Lehum, A. C., Nascimento, J. R., Petrov, A. Yu., Silva, E. O., ...
We develop the superfield approach to the effective potential in three dimensions and calculate the one-loop and two-loop k\"{a}hlerian effective potential in commutative and noncommutative cases.
Dynamical Lorentz symmetry breaking in a 4D four-fermion model at finite temperature (2008)
Gomes, M., Mariz, T., Nascimento, J. R., Santos, A. F., Petrov, A. Yu., Da Silva, A. J.
In a 4D four-fermion model we study the dynamical restoration of Lorentz and CPT symmetries at finite temperature. We evaluate the gap equation both at zero and at finite temperature and observe...
Ferrari, A. F., Gomes, M., Lehum, A. C., Nascimento, J. R., Petrov, A. Yu., Da Silva, A. J.
We study the duality of the supersymmetric self-dual and Maxwell-Chern-Simons theories coupled to a fermionic matter superfield, using a master action. This approach evades the difficulties inherent...
Dynamical Lorentz symmetry breaking in 3D and charge fractionalization (2008)
Charneski, B., Gomes, M., Mariz, T., Nascimento, J. R., Da Silva, A. J.
We analyze the breaking of Lorentz invariance in a 3D model of fermion fields self-coupled through four-fermion interactions. The low-energy limit of the theory contains various sub-models which are...
On the ambiguities in the effective action in Lorentz-violating gravity (2008)
Gomes, M., Mariz, T., Nascimento, J. R., Passos, E., Petrov, A. Yu., Da Silva, A. J.
We investigate the occurrence of ambiguities for Lorentz-violating gravitational Chern-Simons term. It turns out that this term is accompanied by a coefficient depending on an undetermined parameter,...
On duality of the noncommutative Maxwell-Chern-Simons theory (2008)
Gomes, M., Nascimento, J. R., Petrov, A. Yu., Da Silva, A. J., Silva, E. O.
We study the possibility of establishing the dual equivalence between the noncommutative Maxwell-Chern-Simons theory and the noncommutative self-dual theory. It turns to be that whereas in the...
Perturbative finiteness of the three-dimensional Susy QED to all orders (2007)
Ferrari, A. F., Gomes, M., Lehum, A. C., Petrov, A. Yu., Da Silva, A. J.
Within the superfield formalism, we study the ultraviolet properties of the three-dimensional supersymmetric quantum electrodynamics. The theory is shown to be finite at all loops orders in a...
Spontaneous gauge symmetry breaking in a supersymmetric Chern-Simons model (2007)
Lehum, A. C., Ferrari, A. F., Gomes, M., Da Silva, A. J.
This works presents a perturbative analysis of the supersymmetric Chern-Simons model in three spacetime dimensions coupled to a Higgs field, using the superfield formalism. We study the spontaneous...
Dynamical Lorentz and CPT symmetry breaking in a 4D four-fermion model (2007)
Gomes, M., Mariz, T., Nascimento, J. R., Da Silva, A. J.
In a 4D chiral Thirring model we analyse the possibility that radiative corrections may produce spontaneous breaking of Lorentz and CPT symmetry. By studying the effective potential, we verified that...
Ferrari, A. F., Gomes, M., Stechhahn, C. A.
In this work we study modifications in the Aharonov-Bohm effect for relativistic spin 1/2 particles due to the noncommutativity of spacetime in $2 + 1$ dimensions. The noncommutativity gives rise to...
On the finiteness of the noncommutative supersymmetric Maxwell-Chern-Simons theory (2007)
Ferrari, A. F., Gomes, M., Nascimento, J. R., Petrov, A. Yu., Da Silva, A. J., Silva, E. O.
Within the superfield approach, we prove the absence of UV/IR mixing in the three-dimensional noncommutative supersymmetric Maxwell-Chern-Simons theory at any loop order and demonstrate its...
Anomaly cancellation in three-dimensional noncommutative gauge theories (2007)
Gomes, M., Mariz, T., Nascimento, J. R., Petrov, A. Yu., Da Silva, A. J., Silva, E. O.
The anomaly found by Callan and Harvey is shown to be cancelled in a three-dimensional noncommutative gauge theory coupled to a fermion with a mass function depending on one spatial coordinate...
On the induction of the four-dimensional Lorentz-breaking non-Abelian Chern-Simons action (2007)
Gomes, M., Nascimento, J. R., Passos, E., Petrov, A. Yu., Da Silva, A. J.
A four-dimensional Lorentz-breaking non-Abelian Chern-Simons like action is generated as a one-loop perturbative correction via an appropriate Lorentz-breaking coupling of the non-Abelian gauge field...
Finite-size effects on the phase structure of the Nambu-Jona-Lasinio model (2006)
Abreu, L. M., Gomes, M., Da Silva, A. J.
The Nambu-Jona-Lasinio (NJL) model is one of the most frequently used four-fermion models in the study of dynamical symmetry breaking. In particular, the NJL model is convenient for that analysis at...
Lorentz violation in the linearized gravity (2006)
Ferrari, A. F., Gomes, M., Nascimento, J. R., Passos, E., Petrov, A. Yu., Da Silva, A. J.
We study some physical consequences of the introduction of a Lorentz-violating modification term in the linearized gravity, which leads to modified dispersion relations for gravitational waves in the...
The three-dimensional non-anticommutative superspace (2006)
Ferrari, A. F., Gomes, M., Nascimento, J. R., Petrov, A. Yu., Da Silva, A. J.
We propose two alternative formulations for a three-dimensional non-anticommutative superspace in which some of the fermionic coordinates obey Clifford anticommutation relations. For this superspace,...
The three-dimensional noncommutative Gross-Neveu model (2006)
Charneski, B., Ferrari, A. F., Gomes, M.
This work is dedicated to the study of the noncommutative Gross-Neveu model. As it is known, in the canonical Weyl-Moyal approach the model is inconsistent, basically due to the separation of the...
On the duality of three-dimensional superfield theories (2006)
Ferrari, A. F., Gomes, M., Nascimento, J. R. S., Petrov, A. Yu., Da Silva, A. J.
Within the superfield approach, we consider the duality between the supersymmetric Maxwell-Chern-Simons and self-dual theories in three spacetime dimensions. Using a gauge embedding method, we...
Simpson, J. A., Agbenyega, T., Barnes, K. I., Di Perri, G., Folb, P., Gomes, M., ...
Background Intra-rectal artesunate has been developed as a potentially life-saving treatment of severe malaria in rural village settings where administration of parenteral antimalarial drugs is not...
An unusual cause of acute rhabdomyolysis (2006)
Gomes, M., Müller, K., Busch, H., Uhl, M., Kelly, T., Huzly, D., ...
An unusual cause of acute rhabdomyolysis (2006)
Gomes, M., Müller, K., Busch, H., Uhl, M., Kelly, T., Huzly, D., ...
An unusual cause of acute rhabdomyolysis (2006)
Gomes, M., Müller, K., Busch, H., Uhl, M., Kelly, T., Huzly, D., ...
Supersymmetric non-Abelian noncommutative Chern-Simons theory (2005)
Ferrari, A. F., Gomes, M., Petrov, A. Yu., Da Silva, A. J.
In this work, we study the three-dimensional non-Abelian noncommutative supersymmetric Chern-Simons model with the U(N) gauge group. Using a superfield formulation, we prove that, for the pure gauge...
Lorentz symmetry breaking in the noncommutative Wess-Zumino model: One loop corrections (2005)
Ferrari, A. F., Girotti, H. O., Gomes, M.
In this paper we deal with the issue of Lorentz symmetry breaking in quantum field theories formulated in a non-commutative space-time. We show that, unlike in some recente analysis of quantum...
Sepsis Brazil – early results: albumin and mortality rate in septic shock (2005)
David, C, Hatum, R, Andrade, J, Knibel, M, Gomes, M, Duarte, J, ...
No abstract available.
Anacleto, M. A., Gomes, M., Da Silva, A. J., Spehler, D.
We study a noncommutative nonrelativistic fermionic field theory in 2+1 dimensions coupled to the Chern-Simons field. We perform a perturbative analysis of model and show that up to one loop the...
Consistent Interactions of the 2+1 Dimensional Noncommutative Chern-Simons Field (2004)
Asano, E. A., Brito, L. C. T., Gomes, M., Petrov, A. Yu., Da Silva, A. J.
We consider 2+1 dimensional noncommutative models of scalar and fermionic fields coupled to the Chern-Simons field. We show that, at least up to one loop, the model containing only a fermionic field...
Noncommutative Correction to the Aharonov-Bohm Scattering: a Field Theory Approach (2004)
Anacleto, M. A., Gomes, M., Da Silva, A. J., Spehler, D.
We study a noncommutative nonrelativistic theory in 2+1 dimensions of a scalar field coupled to the Chern-Simons field. In the commutative situation this model has been used to simulate the...
On the consistency of the three-dimensional noncommutative supersymmetric Yang-Mills theory (2004)
Ferrari, A. F., Girotti, H. O., Gomes, M., Petrov, A. Yu., Ribeiro, A. A., Da Silva, A. J.
We study the one-loop quantum corrections to the U(N) noncommutative supersymmetric Yang-Mills theory in three spacetime dimensions (NCSYM$_3$). We show that the cancellation of the dangerous UV/IR...
Ferrari, A. F., Girotti, H. O., Gomes, M., Petrov, A. Yu., Ribeiro, A. A., Rivelles, V. O., ...
Commutative four dimensional supersymmetric Yang-Mills (SYM) is known to be renormalizable for ${\mathcal N} = 1, 2$, and finite for ${\mathcal N} = 4$. However, in the noncommutative version of the...
Asano, E. A., Girotti, H. O., Gomes, M., Petrov, A. Yu., Rodrigues, A. G., Da Silva, A. J.
We consider the coupling of fermions to the three-dimensional noncommutative $CP^{N-1}$ model. In the case of minimal coupling, although the infrared behavior of the gauge sector is improved, there...
Ferrari, A. F., Girotti, H. O., Gomes, M., Ribeiro, A. A., Petrov, A. Yu., Da Silva, A. J.
The three-dimensional noncommutative supersymmetric QED is investigated within the superfield approach. We prove the absence of UV/IR mixing in the theory at any loop order and demonstrate its...
Ferrari, A. F., Girotti, H. O., Gomes, M., Petrov, A. Yu., Ribeiro, A. A., Rivelles, V. O., ...
Commutative supersymmetric Yang-Mills is known to be renormalizable for ${\cal N} = 1, 2$, while finite for ${\cal N} = 4$. However, in the noncommutative version of the model (NCSQED$_4$) the UV/IR...
(2+1)D Noncommutative CP$^{N-1}$ Model (2003)
Asano, E. A., Gomes, M., Rodrigues, A. G., Da Silva, A. J.
We investigate possible extensions of the (2+1) dimensional $CP^{N-1}$ model to the noncommutative space. Up to the leading nontrivial order of 1/N, we prove that the model restricted to the left...
Dias, Alex G., Gomes, M., Da Silva, A. J.
We study the vacuum stability of a model of massless scalar and fermionic fields minimally coupled to a Chern-Simons field. The classical Lagrangian only involves dimensionless parameters, and the...
Gomes, M., Perez, Silvana, Da Silva, A. J.
By analyzing the odd parity part of the gauge field two and three point vertex functions, the one-loop radiative correction to the Chern-Simons coefficient is computed in noncommutative...
G. Dire, E. Lima, M. Gomes, M. Bernardo-Filho
The biodistribution of radiopharmaceutical used in diagnostic imaging can be altered by a wide variety of factors. If unknown, the drug interaction with radiopharmaceuticals can lead to misdiagnosis...
Higher loop corrections in noncommutative supersymmetric QED (2002)
Girotti, H. O., Gomes, M., Petrov, A. Yu., Rivelles, V. O., Da Silva, A. J.
This paper has been withdrawn by the authors. It has been superseded by hep-th/0309154
Spontaneous Symmetry Breaking in Noncommutative Field Theory (2002)
Girotti, H. O., Gomes, M., Petrov, A. Yu., Rivelles, V. O., Da Silva, A. J.
The spontaneous symmetry breaking of rotational O(N) symmetry in noncommutative field theory is investigated in a 2+1 dimensional model of scalar fields coupled through a combination of quartic and...
The Three-Dimensional Noncommutative Nonlinear Sigma Model in Superspace (2001)
Girotti, H. O., Gomes, M., Petrov, A. Yu., Rivelles, V. O., Da Silva, A. J.
We study the superspace formulation of the noncommutative nonlinear supersymmetric O(N) invariant sigma-model in 2+1 dimensions. We prove that the model is renormalizable to all orders of 1/N and...
Superfield Effective Action in the Noncommutative Wess-Zumino Model (2001)
Buchbinder, I. L., Gomes, M., Petrov, A. Yu., Rivelles, V. O.
We introduce the concept of superfield effective action in noncommutative N=1 supersymmetric field theories containing chiral superfields. One and two loops low-energy contributions to the effective...
The Noncommutative Supersymmetric Nonlinear Sigma Model (2001)
Girotti, H. O., Gomes, M., Rivelles, V. O., Da Silva, A. J.
We show that the noncommutativity of space-time destroys the renormalizability of the 1/N expansion of the O(N) Gross-Neveu model. A similar statement holds for the noncommutative nonlinear sigma...
Relativistic scalar Aharonov-Bohm scattering (2000)
Gomes, M., Malbouisson, J. M. C., Rodrigues, A. G., Da Silva, A. J.
We discuss the scattering of relativistic spin zero particles by an infinitely long and arbitrarily thin solenoid. The exact solution of the first-quantized problem can be obtained as a mimic of the...
A Consistent Noncommutative Field Theory: the Wess-Zumino Model (2000)
Girotti, H. O., Gomes, M., Rivelles, V. O., Da Silva, A. J.
We show that the noncommutative Wess-Zumino model is renormalizable to all orders of perturbation theory. The noncommutative scalar potential by itself is non-renormalizable but the Yukawa terms...
De Albuquerque, L. C., Gomes, M., Da Silva, A. J.
We apply a soft version of the BPHZ subtraction scheme to the computation of two-loop corrections from an Abelian Chern-Simons field coupled to (massive) scalar matter with a...
Non-Abelian Aharonov-Bohm Scattering of Spin 1/2 Particles (2000)
Gomes, M., Malacarne, L. C., Da Silva, A. J.
We study the low energy regime of the scattering of two fermionic particles carrying isospin 1/2 and interacting through a non-Abelian Chern-Simons field. We calculate the one-loop scattering...
A Renormalization Group Study of the $(\phi^* \phi)^3$ Model coupled to a Chern-Simons Field (2000)
Alves, V. S., Gomes, M., Pinheiro, S. L. V., Da Silva, A. J.
We consider the model of a massless charged scalar field, in (2+1) dimensions, with a self interaction of the form $lambda (\phi^* \phi)^3$ and interacting with a Chern Simons field. We calculate the...
On spin-1 massive particles coupled to a Chern-Simons field (1999)
Gomes, M., Malacarne, L. C., Da Silva, A. J.
We study spin one particles interacting through a Chern-Simons field. In the Born approximation, we calculate the two body scattering amplitude considering three possible ways to introduce the...
Radiative Corrections to the Aharonov-Bohm Scattering (1999)
De Albuquerque, L. C., Gomes, M., Da Silva, A. J.
We consider the scattering of relativistic electrons from a thin magnetic flux tube and perturbatively calculate the order $\alpha$, radiative correction, to the first order Born approximation. We...
Four Fermion Field Theories and the Chern-Simons Field: A Renormalization Group Study (1999)
Alves, V. S., Gomes, M., Pinheiro, S. V. L., Da Silva, A. J.
In (2+1) dimensions, we consider the model of a $N$ flavor, two-component fermionic field interacting through a Chern-Simons field besides a four fermion self-interaction which consists of a linear...
Processing Variables and Failure Properties of Water Atomised Sintered T15 High-Speed Steels. (1998)
Santos, M., Gomes, M., Oliveira, M. M., Rebbeck, M. M., Wronski, A. S.
Water-atomized commercial T15 powder had transverse rupture strength range of 1.4-3.5GPa which was achieved by slightly varying the processing parameters particularly post-sinter HIPping and...
Alves, V. S., Gomes, M., Pinheiro, S. V. L., Da Silva, A. J.
In 2+1 dimensions, for low momenta, using dimensional renormalization we study the effect of a Chern-Simons field on the perturbative expansion of fermions self interacting through a Gross Neveu...
On the Nonabelian Aharonov Bohm Scattering of Spinless Particles (1998)
Gomes, M., Malacarne, L. C., Da Silva, A. J.
The Aharonov Bohm scattering for spinless, isospin 1/2, particles interacting through a nonabelian Chern-Simons field is studied. Starting from the relativistic quantum field theory and using a...
Nonrelativistic Limit of the Scalar Chern-Simons Theory and the Aharonov-Bohm Scattering (1998)
Gomes, M., Malbouisson, J. M. C., Da Silva, A. J.
We study the nonrelativistic limit of the quantum theory of a Chern-Simons field minimally coupled to a scalar field with quartic self-interaction. The renormalization of the relativistic model, in...
On the equivalence of the self-dual and Maxwell-Chern-Simons models coupled to Fermions (1997)
Gomes, M., Malacarne, L. C., Da Silva, A. J.
We study the exact equivalence between the self-dual model minimally coupled with a Dirac field and the Maxwell-Chern-Simons model with non-minimal magnetic coupling to fermions. We show that the...
Starting from a relativistic quantum field theory, we study the low energy scattering of two fermions of opposite spins interacting through a Chern-Simons field. Using the Coulomb gauge we implement...
The Low Energy Limit of the Chern-Simons Theory Coupled to Fermions (1997)
Girotti, H. O., Gomes, M., Nascimento, J. R., Da Silva, A. J.
We study the nonrelativistic limit of the theory of a quantum Chern--Simons field minimally coupled to Dirac fermions. To get the nonrelativistic effective Lagrangian one has to incorporate vacuum...
Duality Symmetry in the Schwarz-Sen Model (1997)
Girotti, H. O., Gomes, M., Rivelles, V. O., Da Silva, A. J.
The continuous extension of the discrete duality symmetry of the Schwarz-Sen model is studied. The corresponding infinitesimal generator $Q$ turns out to be local, gauge invariant and metric...
Relativistic Corrections to the Aharonov-Bohm Scattering (1996)
Gomes, M., Malbouisson, J. M. C., Da Silva, A. J.
We determine the |p|/m expansion of the two body scattering amplitude of the quantum theory of a Chern-Simons field minimally coupled to a scalar field with quartic self-interaction. It is shown that...
On the Nonrelativistic Limit of the phi^4 Theory in 2+1 Dimensions (1996)
Gomes, M., Malbouisson, J. M. C., Da Silva, A. J.
We study the nonrelativistic limit of the quantum theory of a real scalar field with quartic self-interaction. The two body scattering amplitude is written in such way as to separate the...
Canonical Quantization of the Maxwell-Chern-Simons Theory in the Coulomb Gauge (1994)
Devecchi, F. P., Fleck, M., Girotti, H. O., Gomes, M., Da Silva, A. J.
The Maxwell-Chern-Simons theory is canonically quantized in the Coulomb gauge by using the Dirac bracket quantization procedure. The determination of the Coulomb gauge polarization vector turns out...
Attractive Forces Between Electrons in QED$_{3}$ (1992)
Girotti, H. O., Gomes, M., DeLyra, J. L., Mendes, R. S., Nascimento, J. R. S., Da Silva, A. J.
Vacuum polarization effects are non-perturbatively incorporated into the photon propagator to eliminate the severe infrared problems characteristic of QED$_3$. The theory is thus rephrased in terms...
Electron--Electron Bound States in QED$_{3}$ (1992)
Girotti, H. O., Gomes, M., DeLyra, J. L., Mendes, R. S., Nascimento, J. R. S., Da Silva, A. J.
This paper is dedicated to the study of the existence and the properties of electron-electron bound states in QED$_3$. A detailed analysis of the infrared structure of the perturbative series of the...
Chiral Bosons Through Linear Constraints (1992)
Girotti, H. O., Gomes, M., Rivelles, V. O.
We study in detail the quantization of a model which apparently describes chiral bosons. The model is based on the idea that the chiral condition could be implemented through a linear constraint. We...
Left ventricular function after total correction of tetralogy of Fallot (1991)
BASTOS, P., CAMPOS, J., CUNHA, D., GOMES, M.
Conflicting data are available concerning left ventricular (LV) function in patients after total correction of tetralogy of Fallot (TOF). The response to afterload stress determined by methoxamine...
Left ventricular function after total correction of tetralogy of Fallot (1991)
BASTOS, P., CAMPOS, J., CUNHA, D., GOMES, M.
Conflicting data are available concerning left ventricular (LV) function in patients after total correction of tetralogy of Fallot (TOF). The response to afterload stress determined by methoxamine...
STUDY OF PHASE COHERENCE TIMES OF CuCl (1988)
Gomes, M., Kippelen, B., HÖnerlage, B., Levy, R.
We perform time-resolved degenerate four-wave mixing measurements using a streak camera system, in order to study the dynamics of coherent biexciton states in CuCl.
STUDY OF PHASE COHERENCE TIMES OF CuCl (1988)
Gomes, M., Kippelen, B., HÖnerlage, B., Levy, R.
We perform time-resolved degenerate four-wave mixing measurements using a streak camera system, in order to study the dynamics of coherent biexciton states in CuCl.
STUDY OF PHASE COHERENCE TIMES OF CuCl (1988)
Gomes, M., Kippelen, B., HÖnerlage, B., Levy, R.
We perform time-resolved degenerate four-wave mixing measurements using a streak camera system, in order to study the dynamics of coherent biexciton states in CuCl.
Zeitlyn, S., Rahman, A. K., Nielsen, B. H., Gomes, M., Kofoed, P. E., Mahalanabis, D.
OBJECTIVE--To evaluate factors associated with non-compliance with having second vaccination against diphtheria, tetanus, and pertussis in a treatment centre in Dhaka to determine which children were...
Bias reduction in risk modelling: Semi-parametric quantile estimation
Heavy tails, high quantiles, semi-parametric estimation, bias reduction, statistics of extremes, Primary 62G32, 62E20, Secondary 65C05,
A. Vaz, Edite Fernandes, M. Gomes
Dual parametrization, sequential quadratic programming, semi-infinite programming, 90C34, 49M29, 49M37,
Interventions to improve the use of antimalarials in south-east Asia: an overview.
Gomes, M., Wayling, S., Pang, L.
There are few drugs for malaria, and those which are available for use are subject to rapid development of resistance. Curiously, little effort has been made to improve drug use in malaria-endemic...
Symptomatic identification of malaria in the home and in the primary health care clinic.
Gomes, M., Espino, F. E., Abaquin, J., Realon, C., Salazar, N. P.
In endemic areas in the absence of microscopy, the WHO case definition of malaria is the presence or a history of fever without other obvious cause. Yet there is little empirical evidence on the...
Semi-parametric second-order reduced-bias high quantile estimation
Heavy tails, High quantiles, Semi-parametric estimation, Statistics of extremes, 62G32, 62E20, 65C05,