1,305 research outputs found
Métodos de fracionamento e caracterização da matéria orgânica do solo.
bitstream/item/32410/1/documento-106.pd
Efeito estufa: potencialidades e contribuições da agricultura.
bitstream/item/32413/1/documento-109.pd
Role of beam propagation in Goos-H\"{a}nchen and Imbert-Fedorov shifts
We derive the polarization-dependent displacements parallel and perpendicular
to the plane of incidence, for a Gaussian light beam reflected from a planar
interface, taking into account the propagation of the beam. Using a
classical-optics formalism we show that beam propagation may greatly affect
both Goos-H\"{a}nchen and Imbert-Fedorov shifts when the incident beam is
focussed.Comment: 3 pages, 1 figure, submitted to Opt. Let
Equation of motion for dislocations with inertial effects
An approximate equation of motion is proposed for screw and edge
dislocations, which accounts for retardation and for relativistic effects in
the subsonic range. Good quantitative agreement is found, in accelerated or in
decelerated regimes, with numerical results of a more fundamental nature.Comment: 6 pages, 4 figures, LaTe
Systematics of Xanthorrhoeaceae Sensu Lato, with an Emphasis on Bulbine
We provide here results of a combined analysis of plastid genes rbcL, matK, and ndhF for Xanthorrhoeaceae s.l., the Asphodelaceae/Xanthorrhoeaceae/Hemerocallidaceae clade, which are well supported by the DNA data. Xanthorrhoea (often treated as the sole member of Xanthorrhoeaceae) is sister to the hemerocallid clade (former Hemerocallidaceae); and the asphodelid clade (formerly Asphodelaceae) is sister to them both. For additional species of Bulbine and Jodrellia (both Asphodeloideae), we also collected rps16 intron and ITS nuclear ribosomal DNA sequences to better assess their relationships. Bulbine, with Jodrellia, embedded are sister to the collective genera of subfamily Alooideae in which all species are characterized by strongly bimodal and nearly identical karyotypes, whereas that of Bulbine is much more variable. Cytological studies have previously shown Bulbine to possess a range of karyotypes from graduated to clearly bimodal (although never exactly like the aloid genera) and point toward a lower level of bimodality in the Australian members, all of which are autotetraploid, than in the African members, all of which are diploid. Therefore, there have been two events of particular interest within Bulbine, a change in ploidy and a long-range dispersal event
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