BFFT quantization with nonlinear constraints

We consider the method due to Batalin, Fradkin, Fradkina, and Tyutin (BFFT) that makes the conversion of second-class constraints into first-class ones for the case of nonlinear theories. We first present a general analysis of an attempt to simplify the method, showing the conditions that must be fulfilled in order to have first-class constraints for nonlinear theories but that are linear in the auxiliary variables. There are cases where this simplification cannot be done and the full BFFT method has to be used. However, in the way the method is formulated, we show with details that it is not practicable to be done. Finally, we speculate on a solution for these problems.Comment: 19 pages, Late

Axial and gauge anomalies in a theory with one and two-form gauge fields

We study the problem of axial and gauge anomalies in a reducible theory involving vector and tensor gauge fields coupled in a topological way. We consider that vector and axial fermionic currents couple with the tensor field in the same topological manner as the vector gauge one. This kind of coupling leads to an anomalous axial current, contrarily to the results found in literature involving other tensor couplings, where no anomaly is obtained.Comment: 9 pages, Latex - To appear in Phys. Lett.

BV QUANTIZATION OF A VECTOR-TENSOR GAUGE THEORY WITH TOPOLOGICAL COUPLING

We use the BV quantization method for a theory with coupled tensor and vector gauge fields through a topological term. We consider in details the reducibility of the tensorial sector as well as the appearance of a mass term in the effective vectorial theory .Comment: 10 pages, Late

Compactification of gauge theories and the gauge invariance of massive modes

We study the gauge invariance of the massive modes in the compactification of gauge theories from D=5 to D=4. We deal with Abelian gauge theories of rank one and two, and with non-Abelian ones of rank one. We show that St\"uckelberg fields naturally appear in the compactification mechanism, contrarily to what usually occurs in literature where they are introduced by hand, as a trick, to render gauge invariance for massive theories. We also show that in the non-Abelian case they appear in a very different way when compared with their usual implementation in the non-Abelian Proca model.Comment: 5 pages, Revtex (multicol), minor correction

Impact of the lipid-based nutrient supplements on prevention and treatment of childhood moderate undernutrition

Purpose: This review aims at assessing the effectiveness of LNS interventions for prevention and/or treatment of moderate acute malnutrition (MAM), stunting and other anthropometric indicators for undernutrition in children younger than 5 years. Methodology: Eighteen clinical trials on LNS (soybased or milk-based) supplementation in children were compared with habitual diet/control or corn-soy blend (CSB). Mean changes in height for age (HAZ), weight for age (WAZ) and weight for height z-scores (WHZ) were assessed as primary outcomes. The secondary outcomes included: weight gain, height, mid upper arm circumference (MUAC), recovery from MAM, occurrence of fever, diarrhoea and cough. Findings: The pooled estimate revealed a statistically significant increase in WAZ (weighted mean difference [WMD] =0.09; 95%CI= 0.02, 0.15; p=0.01), WHZ (WMD=0.14; 95%CI= 0.01, 0.26; p=0.000) and improved recovery from MAM (Risk Ratio [RR] = 1.37; 95%CI= 1.14, 1.65; p=0.000) in children receiving LNS compared with control or CBS. No significant effect was observed in HAZ (WMD=0.00;95%CI=-0.02,0.03: p=0.578). Children fed with milk-based LNS (RR=1.68; 95%CI=1.17, 2.39; p=0.005) were more likely to recover significantly from MAM when compared with CSB. Conclusion: Although there is evidence that LNS yield better nutritional outcomes than CSB and control, it is impossible to conclude that the milk-based LNS are superior to soy-based LNS and whether age and duration of intervention significantly affect the effectiveness of LNS on childhood undernutrition. Further research is required before these products can be recommended at scale

Functional versus canonical quantization of a nonlocal massive vector-gauge theory

It has been shown in literature that a possible mechanism of mass generation for gauge fields is through a topological coupling of vector and tensor fields. After integrating over the tensor degrees of freedom, one arrives at an effective massive theory that, although gauge invariant, is nonlocal. Here we quantize this nonlocal resulting theory both by path integral and canonical procedures. This system can be considered as equivalent to one with an infinite number of time derivatives and consequently an infinite number of momenta. This means that the use of the canonical formalism deserves some care. We show the consistency of the formalism we use in the canonical procedure by showing that the obtained propagators are the same as those of the (Lagrangian) path integral approach. The problem of nonlocality appears in the obtainment of the spectrum of the theory. This fact becomes very transparent when we list the infinite number of commutators involving the fields and their velocities.Comment: 12 pages, Latex, to appear in J. Math. Phy