A laser technique for characterizing the geometry of plant canopies

The interception of solar power by the canopy is investigated as a function of solar zenith angle (time), component of the canopy, and depth into the canopy. The projected foliage area, cumulative leaf area, and view factors within the canopy are examined as a function of the same parameters. Two systems are proposed that are capable of describing the geometrical aspects of a vegetative canopy and of operation in an automatic mode. Either system would provide sufficient data to yield a numerical map of the foliage area in the canopy. Both systems would involve the collection of large data sets in a short time period using minimal manpower

Perfil andrológico de touros nelore criados extensivamente no planalto e no Pantanal sul-mato-grossense.

bitstream/item/56426/1/CT100-lancado.pdfNa publicação: Juliana Corrêa Borges

Radiative corrections in bumblebee electrodynamics

We investigate some quantum features of the bumblebee electrodynamics in flat spacetimes. The bumblebee field is a vector field that leads to a spontaneous Lorentz symmetry breaking. For a smooth quadratic potential, the massless excitation (Nambu-Goldstone boson) can be identified as the photon, transversal to the vacuum expectation value of the bumblebee field. Besides, there is a massive excitation associated with the longitudinal mode and whose presence leads to instability in the spectrum of the theory. By using the principal-value prescription, we show that no one-loop radiative corrections to the mass term is generated. Moreover, the bumblebee self-energy is not transverse, showing that the propagation of the longitudinal mode can not be excluded from the effective theory.Comment: Revised version: contains some more elaborated interpretation of the results. Conclusions improve

Redução da proporção touro:vaca no Pantanal Mato-Grossense.

Este trabalho foi conduzido com o objetivo de proporcionar alternativas de reducao da proporcao touro:vaca no Pantanal e, consequentemente, reduzir os custos de producao da pecuaria de corte regional. Utilizaram-se as proporcoes de 1:10, 1:25 e 1:40 em pastagens nativas com taxa de lotacao media de 0,28 UA/ha durante duas estacoes de monta consecutivas. A analise estatistica dos dados nao revelou efeito significativo para os seguintes fatores: ano (P=2.097), categoria animal (P=0,0773) e proporcao touro:vaca (P=8.134). Entretanto, para a variavel tipo de acasalamento (individuo ou multiplo), o sistema multiplo mostrou-se superior (P=0,0228) ao individual. Avaliou-se o impacto economico desta pratica de manejo no sistema de criacao extensivo do Pantanal e concluiu-se estar havendo subutilizacao de touros na regiao, na proporcao de 1:10. A utilizacao da proporcao 1:25 ou 1:40 reduziu os custos de producao do bezerro nascido em 60% e 75%, respectivamente.bitstream/item/37571/1/CT26.pd