The Role of Fermions in Bubble Nucleation

We present a study of the role of fermions in the decay of metastable states of a scalar field via bubble nucleation. We analyze both one and three-dimensional systems by using a gradient expansion for the calculation of the fermionic determinant. The results of the one-dimensional case are compared to the exact results of previous work.Comment: 15 pages, revtex, 9 figure

Uniform semiclassical approximation in quantum statistical mechanics

We present a simple method to deal with caustics in the semiclassical approximation to the partition function of a one-dimensional quantum system. The procedure, which makes use of complex trajectories, is applied to the quartic double-well potential.Comment: 5 pages, 1 figure, Latex. Contribution to the Proceedings of the XXI Brazilian National Meeting on Particles and Fields (Sao Lourenco, October 23-27, 2000

Improved semiclassical density matrix: taming caustics

We present a simple method to deal with caustics in the semiclassical approximation to the thermal density matrix of a particle moving on the line. For simplicity, only its diagonal elements are considered. The only ingredient we require is the knowledge of the extrema of the Euclidean action. The procedure makes use of complex trajectories, and is applied to the quartic double-well potential.Comment: 20 pages, 7 figures. Revised version, accepted for publication in Phys. Rev.

Sustainability index for agribusiness products considering territorial bases and life cycle thinking.

The sustainability index (SI) development for agricultural products was a Brazilian Agricultural, Livestock and Provisioning Ministry, (MAPA) demand. This work seeks by participative process, to define sustainability principles, criteria and agricultural products patterns. Theses principles have universal characters liable to expand its application to several agribusiness links by future criteria in the several territorial contexts through out the patterns to be defined to each biome monitored by satellites. The SI must have credibility and international recognition. Among their principles are: Conformity with the agreement, treaties and international conventions; Conformity with the national legislation; Localization; Integration; Monitoring and continuous improvement. The participative elaboration of the sustainability principles with the more representative agribusiness sectors, science and technology areas and the public and private institutions is allowing delineating the environment conduct, innovation and business for a future guiding to criteria formatting of the and SI patterns

Characterisation of the production system of dairy and beef farmers from Iporá and neighbourhood, Goiás State, Brazil.

The objective of the present study was to characterise the livestock production system of dairy and beef farmers in Iporá and surrounding municipalities in Goiás (Amorinópolis, Diorama, Israelândia, Ivolândia and Jaupaci) through a structured modular questionnaire

Relações hídricas de gravioleiras (Annona muricata L.) jovens em porta-enxertos dos gêneros Annona e Rollinia.

Publicado também: FRAZÃO, D. A. C.; HOMMA, A. K. O; VIÉGAS, I. de J. M. (Ed.). Contribuição ao desenvolvimento da fruticultura na Amazônia. Belém, PA: Embrapa Amazônia Oriental, 2006. p. 543-548