14,926 research outputs found
Position-dependent-mass; Cylindrical coordinates, separability, exact solvability, and PT-symmetry
The kinetic energy operator with position-dependent-mass in cylindrical
coordinates is obtained. The separability of the corresponding Schr\"odinger
equation is discussed within radial cylindrical mass settings. Azimuthal
symmetry is assumed and spectral signatures of various z-dependent interaction
potentials (Hermitian and non-Hermitian PT-symmetric) are reported.Comment: 16 page
Influência do lodo de esgoto na população de minhoca em cultura da bananeira.
bitstream/CNPMA/5831/1/comunicado_26.pd
Caracterização molecular de linhagens de arroz componentes do ensaio de vcu do ano 2010/2011.
O objetivo deste trabalho foi caracterizar a diversidade genética de linhagens e cultivares de arroz componentes do ensaio de VCU de terras altas do ano agrícola 2010/2011, pertencentes do programa de melhoramento da Embrapa Arroz e Feijão
Medida indireta da clorofila e sua relação com o manejo da adubação nitrogenada em plantas de camucamu fertirrigadas.
Biologia reprodutiva de pornunça (Manihot sp. - Euphorbiaceae) em área da Embrapa Semi-Árido, Petrolina-PE.
Com o objetivo de contribuir com informações sobre a biologia reprodutiva da espécie, o presente trabalho foi realizado na área da Embrapa Semi-Árido, PetrolinaPE (9º00? S, 40º22? W, 350 m de altitude) no período de janeiro a março 2003. As observações foram feitas em 12 indivíduos de Manihot sp., onde flores marcadas foram acompanhadas diariamente
Fast ray-tracing algorithm for circumstellar structures (FRACS). II. Disc parameters of the B[e] supergiant CPD-57° 2874 from VLTI/MIDI data
B[e] supergiants are luminous, massive post-main sequence stars exhibiting
non-spherical winds, forbidden lines, and hot dust in a disc-like structure.
The physical properties of their rich and complex circumstellar environment
(CSE) are not well understood, partly because these CSE cannot be easily
resolved at the large distances found for B[e] supergiants (typically \ga
1~kpc). From mid-IR spectro-interferometric observations obtained with
VLTI/MIDI we seek to resolve and study the CSE of the Galactic B[e] supergiant
CPD-57\degr\,2874. For a physical interpretation of the observables
(visibilities and spectrum) we use our ray-tracing radiative transfer code
(FRACS), which is optimised for thermal spectro-interferometric observations.
Thanks to the short computing time required by FRACS (~s per monochromatic
model), best-fit parameters and uncertainties for several physical quantities
of CPD-57\degr\,2874 were obtained, such as inner dust radius, relative flux
contribution of the central source and of the dusty CSE, dust temperature
profile, and disc inclination. The analysis of VLTI/MIDI data with FRACS
allowed one of the first direct determinations of physical parameters of the
dusty CSE of a B[e] supergiant based on interferometric data and using a full
model-fitting approach. In a larger context, the study of B[e] supergiants is
important for a deeper understanding of the complex structure and evolution of
hot, massive stars
Bioactive compounds in the peel of camu camu genotypes from Embrapa's active germplasm bank.
Our objective in this work was to evaluate the contents of the major bioactive compounds in the peel of three genotypes of camu camu at different maturity stages. The genotypes had high concentration of ascorbic acid in the peel ranging from 13.73% to 24.02%. In the ripe maturity stage the genotypes 17 and 44 presented the highest concentration of phenolics (3,299.97 mg GAE.100 g-1) and anthocyanins (165.91 g.100 g-1). Flavonols and carotenoids showed a distinct and statistically different behavior in each genotype. Genotype 44 in the ripe stage had the highest content of carotenoids (105.88 mg.100 g-1). The high contents of vitamin C and phenolic compounds make the residue of camu camu fruit processing a rich source of antioxidants to the food and/or pharmaceutical industries
Classical and quantum quasi-free position dependent mass; P\"oschl-Teller and ordering-ambiguity
We argue that the classical and quantum mechanical correspondence may play a
basic role in the fixation of the ordering-ambiguity parameters. We use
quasi-free position-dependent masses in the classical and quantum frameworks.
The effective P\"oschl-Teller model is used as a manifested reference potential
to elaborate on the reliability of the ordering-ambiguity parameters available
in the literature.Comment: 10 page
Sugarcane in Brazil: current technologic stage and perspectives.
This article aims at analyzing the sugarcane culture in Brazil, showing the current agricultural and industrial development stage of the sugar-alcohol industry and how important this culture has become. It discusses its technologic evolution and the technologies that are being developed in the fields of genetic improvement and new cultural practices, and it aims at estimating the benefits that can be obtained in the next few years with the use of new varieties with specific characteristics, proper varietal management and modern cultural practices. By using data from IBGE (the Brazilian Institute of Geography and Statistics), the productivity of Brazil and of the North, Northeast, South- East, Middle-West and South regions of the country were estimated based on the genetic potential from new varieties and on the use of new cultural practices. Using information from the results of the agricultural research, it was possible to conclude that a significant raise of sugarcane productivity levels in Brazil, due to genetic improvement, is bound to happen in the next few years.Na publicação: Eliseu Alves
- …