Cultivo de abóbora do tipo japonesa por semeio direto e por transplante de mudas em diferentes sistemas de plantio.

Esse trabalho teve por objetivo avaliar duas cultivares de abóbora tipo japonesa (Jabras e Fortuna) em três sistemas de plantio (sistema de plantio direto - SPD, Sistema de plantio convencional com preparo do solo SPC e dois métodos de plantio (semeio direto no local definitivo e transplante de mudas produzidas em bandeijas.Suplemento. Trabalho apresentado no 52. Congresso Brasileiro de Olericultura, Salvador, 2012

Bremsstrahlung in the gravitational field of a cosmic string

In the framework of QED we investigate the bremsstrahlung process for an electron passing by a straight static cosmic string. This process is precluded in empty Minkowski space-time by energy and momentum conservation laws. It happens in the presence of the cosmic string as a consequence of the conical structure of space, in spite of the flatness of the metric. The cross section and emitted electromagnetic energy are computed and analytic expressions are found for different energies of the incoming electron. The energy interval is divided in three parts depending on whether the energy is just above electron rest mass $M$, much larger than $M$, or exceeds $M/\delta$, with $\delta$ the string mass per unit length in Planck units. We compare our results with those of scalar QED and classical electrodynamics and also with conic pair production process computed earlier.Comment: 21 pages, to appear in Phys. Rev. D., KONS-RGKU-94-0