Closed String Thermal Torus From Thermo Field Dynamics

In this Letter a topological interpretation for the string thermal vacuum in the Thermo Field Dynamics (TFD) approach is given. As a consequence, the relationship between the Imaginary Time and TFD formalisms is achieved when both are used to study closed strings at finite temperature. The TFD approach starts by duplicating the system's degrees of freedom, defining an auxiliary (tilde) string. In order to lead the system to finite temperature a Bogoliubov transformation is implemented. We show that the effect of this transformation is to glue together the string and the tilde string to obtain a torus. The thermal vacuum appears as the boundary state for this identification. Also, from the thermal state condition, a Kubo-Martin-Schwinger condition for the torus topology is derived.Comment: 14 pages, revtex4, changes in the text and references. Version to be published in Physics Letters

TFD Approach to Bosonic Strings and DPD_{P}-branes

In this work we explain the construction of the thermal vacuum for the bosonic string, as well that of the thermal boundary state interpreted as a $D_{p}$-brane at finite temperature. In both case we calculate the respective entropy using the entropy operator of the Thermo Field Dynamics Theory. We show that the contribution of the thermal string entropy is explicitly present in the $D_{p}$-brane entropy. Furthermore, we show that the Thermo Field approach is suitable to introduce temperature in boundary states.Comment: 6 pages, revtex, typos are corrected. Prepared for the Second Londrina Winter School-Mathematical Methods in Physics, August 25-30, 2002, Londrina-Pr, Brazil. To appear in a special issue of IJMP

Efeito de substratos e da idade do porta-enxerto na formação de mudas de cajueiro anão precoce (Anacardium occidentale L.) em tubetes.

O objeto deste estudo foi avaliar o efeito de diferentes substratos e idades do porta-enxertos na formação de mudas de cajueiro anão precoce utilizando tubetes como recipiente.bitstream/item/83521/1/CT1220001.pd

Efeitos de substratos e da idade do porta-enxerto na formação de mudas de cajueiro anão precoce (Anacardium occidentale l.) em tubetes.

Os objetivos deste estudo sao avaliar os efeitos de diferentes substratoe idades do porta-enxerto na formacao de mudas de cajueriro anao precoce, utilizando como recipiente o tubete.bitstream/CNPAT-2010/5383/1/Pa-074.pd