Perceived motor ability and selection, optimization, and compensation: Effects of age and institutionalization

The authors examined the mediation effect of the perceived motor ability (PMA) on the direct “effects” of age (third vs. fourth age) and residential status (institutionalized vs. communitarians) on selection, optimization, and compensation (SOC) strategies. With a non-probabilistic sample of 107 elders (Mdn = 80 years) from urban areas, and controlled for cognitive impairment and depression, the authors analysed the structural component of the path model with latent constructs that represents those relationships. This was made only after the structural validity of the constructs had been assured. Constructs were operationalized through the PMA questionnaire and a 16-item version of the SOC questionnaire. Only age had direct effects on the constructs: lower PMA and lower SOC of the elders in the fourth age. Authors also verified that the PMA mediation effect was partial

Higher-derivative non-Abelian gauge fields via the Faddeev-Jackiw formalism

In this paper we analyze two higher-derivative theories, the generalized electrodynamics and the Alekseev-Arbuzov-Baikov's effective Lagrangian from the point of view of Faddeev-Jackiw sympletic approach. It is shown that the full set of constraint is obtained directly from the zero-mode eigenvectors, and that they are in accordance with known results from Dirac's theory, a remnant and recurrent issue in the literature. The method shows to be rather economical in relation to the Dirac's one, obviating thus unnecessary classification and calculations. Afterwards, to conclude we construct the transition-amplitude of the non-Abelian theory following a constrained BRST-method.Comment: 17 page

Nonperturbative Aspects of the two-dimensional Massive Gauged Thirring Model

In this paper we present a study based on the use of functional techniques on the issue of insertions of massive fermionic fields in the two-dimensional massless Gauged Thirring Model. As it will be shown, the fermionic mass contributes to the Green's functions in a surprisingly simple way, leaving therefore the original nonperturbative nature of the massless results still intact in the massive theory. Also, by means of complementarity, we present a second discussion of the massive model, now at its bosonic representation.Comment: 18 pages, to appear at Int. J. Mod. Phys.

Path-ordered Phase Factors in Scalar Quantum Electrodynamics

Starting from linear equations for the complex scalar field, the two- and three-point Green's functions are obtained in the infrared approximation. We show that the infrared singularity factorizes in the vertex function as in spinorial QED, reproducing in a straightforward way the result of lenghty perturbative calculations.Comment: 11 pages, LaTe

What's Wrong with Pauli-Villars Regularization in QED3QED_{3} ?

In this letter we argue that there is no ambiguity between the Pauli-Villars and other methods of regularization in (2+1)-dimensional quantum electrodynamics with respect to dynamical mass generation, provided we properly choose the couplings for the regulators.Comment: 07 pages, Latex, no figure

Equivalence of Many-Gluon Green Functions in Duffin-Kemmer-Petieu and Klein-Gordon-Fock Statistical Quantum Field Theories

We prove the equivalence of many-gluon Green functions in Duffin-Kemmer-Petieu and Klein-Gordon-Fock statistical quantum field theories. The proof is based on the functional integral formulation for the statistical generating functional in a finite-temperature quantum field theory. As an illustration, we calculate one-loop polarization operators in both theories and show that their expressions indeed coincide.Comment: 8 page