The Experts below are selected from a list of 82767 Experts worldwide ranked by ideXlab platform
Ralph Teixeira - One of the best experts on this subject based on the ideXlab platform.
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area distances of convex plane curves and improper affine spheres
Siam Journal on Imaging Sciences, 2008Co-Authors: Marcos Craizer, Moacyr Alvim, Ralph TeixeiraAbstract:The area distance to a convex plane curve is an important concept in computer vision. In this paper we describe a strong link between area distances and improper affine spheres. Based on this link, we propose an extremely fast algorithm to compute the inner area distance. Moreover, the concepts of the theory of affine spheres lead to a new definition of an area distance on the Outer Part of a convex plane curve. On the other hand, area distances provide a good geometrical understanding of improper affine spheres.
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area distances of convex plane curves and improper affine spheres
arXiv: Differential Geometry, 2007Co-Authors: Marcos Craizer, Moacyr Alvim, Ralph TeixeiraAbstract:The area distance to a convex plane curve is an important concept in computer vision. In this paper we describe a strong link between area distances and improper affine spheres. This link makes possible a better understanding of both theories. The concepts of the theory of affine spheres lead to a new definition of an area distance on the Outer Part of a convex plane arc. Also, based on the theory of discrete affine spheres, we propose fast algorithms to compute the area distances. On the other hand, area distances provide a good geometrical understanding of improper affine spheres.
Patricia A B Ramos - One of the best experts on this subject based on the ideXlab platform.
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phenolic composition and antioxidant activity of different morphological Parts of cynara cardunculus l var altilis dc
Industrial Crops and Products, 2014Co-Authors: Patricia A B Ramos, Sonia A O Santos, ângela R Guerra, Olinda Guerreiro, Carmen S R Freire, Silvia M Rocha, Maria F Duarte, Armando J D SilvestreAbstract:The phenolic composition of Cynara cardunculus L. var. altilis (DC) from south of Portugal was determined by analyzing the methanol/water/acetic acid (49.5:49.5:1) extracts of the different morphological Parts of the plant, through high temperature-ultra high pressure liquid chromatography–tandem mass spectrometry. From the twenty-eight phenolic compounds identified, eriodictyol hexoside was described for the first time in C. cardunculus L., and 1,4-di-O-caffeoylquinic acid, naringenin 7-O-glucoside, naringenin rutinoside, naringenin, luteolin acetyl-hexoside and apigenin acetyl-hexoside as cardoon components. Stalks Outer Part and capitula florets showed the highest hydroxycinnamic acids and flavonoids contents, respectively. Capitula receptacle and bracts, and stalks inner Part also presented considerably high hydroxycinnamic acids contents, while leaves were rich in flavonoids. Finally, stalks Outer Part and capitula receptacle and bracts extracts showed the highest antioxidant activity which was in perfect tune with the phenolic compounds, Particularly to hydroxycinnamic acids. These results clearly demonstrate the potential of this crop as a source of antioxidant phenolic compounds.
Marcos Craizer - One of the best experts on this subject based on the ideXlab platform.
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area distances of convex plane curves and improper affine spheres
Siam Journal on Imaging Sciences, 2008Co-Authors: Marcos Craizer, Moacyr Alvim, Ralph TeixeiraAbstract:The area distance to a convex plane curve is an important concept in computer vision. In this paper we describe a strong link between area distances and improper affine spheres. Based on this link, we propose an extremely fast algorithm to compute the inner area distance. Moreover, the concepts of the theory of affine spheres lead to a new definition of an area distance on the Outer Part of a convex plane curve. On the other hand, area distances provide a good geometrical understanding of improper affine spheres.
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area distances of convex plane curves and improper affine spheres
arXiv: Differential Geometry, 2007Co-Authors: Marcos Craizer, Moacyr Alvim, Ralph TeixeiraAbstract:The area distance to a convex plane curve is an important concept in computer vision. In this paper we describe a strong link between area distances and improper affine spheres. This link makes possible a better understanding of both theories. The concepts of the theory of affine spheres lead to a new definition of an area distance on the Outer Part of a convex plane arc. Also, based on the theory of discrete affine spheres, we propose fast algorithms to compute the area distances. On the other hand, area distances provide a good geometrical understanding of improper affine spheres.
K V Manukovskii - One of the best experts on this subject based on the ideXlab platform.
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a two dimensional hydrostatically equilibrium atmosphere of a neutron star with given differential rotation
arXiv: Astrophysics, 2004Co-Authors: V S Imshennik, K V ManukovskiiAbstract:An analytic solution has been found in the Roche approximation for the axially symmetric structure of a hydrostatically equilibrium atmosphere of a neutron star produced by collapse. A hydrodynamic (quasione-dimensional) model for the collapse of a rotating iron core in a massive star gives rise to a heterogeneous rotating protoneutron star with an extended atmosphere composed of matter from the Outer Part of the iron core with differential rotation (Imshennik and Nadyozhin, 1992). The equation of state of a completely degenerate iron gas with an arbitrary degree of relativity is taken for the atmospheric matter. We construct a family of toroidal model atmospheres with total masses $M \approx 0.1 \div 0.2 M_{\odot}$ and total angular momenta $J \approx (1 \div 5.5) \cdot 10^{49} erg \cdot s$, which are acceptable for the Outer Part of the collapsed iron core, in accordance with the hydrodynamic model, as a function of constant parameters $\omega_{0} and r_{0}$ of the specified differential rotation law $\Omega = \omega_{0}\exp{\Big[-\frac{(r\sin{\Theta})^{2}}{r_{0}^{2}}\Big]}$ in spherical coordinates. The assumed rotation law is also qualitatively consistent with the hydrodynamic model for the collapse of an iron core.
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a two dimensional hydrostatically equilibrium atmosphere of a neutron star with given differential rotation
Astronomy Letters, 2000Co-Authors: V S Imshennik, K V ManukovskiiAbstract:An analytic solution has been found in the Roche approximation for the axially symmetric structure of a hydrostatically equilibrium atmosphere of a neutron star produced by collapse. A hydrodynamic (quasione-dimensional) model for the collapse of a rotating iron core in a massive star gives rise to a heterogeneous rotating protoneutron star with an extended atmosphere composed of matter from the Outer Part of the iron core with differential rotation (Imshennik and Nadyozhin, 1992). The equation of state of a completely degenerate iron gas with an arbitrary degree of relativity is taken for the atmospheric matter. We construct a family of toroidal model atmospheres with total masses M≈ 0.1−2M⊙ and total angular momenta J≈(1−5.5)×49 erg s, which are acceptable for the Outer Part of the collapsed iron core, in accordance with the hydrodynamic model, as a function of constant parameters ω0 and r0 of the specified differential rotation law Ω=ω0exp[−(rsinθ)2/r 0 2 ] in spherical coordinates. The assumed rotation law is also qualitatively consistent with the hydrodynamic model for the collapse of an iron core.
J. Spitale - One of the best experts on this subject based on the ideXlab platform.
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Physical Characteristics and Non-Keplerian Orbital Motion of "Propeller" Moons Embedded in Saturn's Rings
The Astrophysical Journal, 2010Co-Authors: Matthew S. Tiscareno, Joseph A. Burns, Miodrag Sremčević, K. Beurle, Matthew M. Hedman, Nicholas J. Cooper, Anthony J. Milano, M. W. Evans, Carolyn C. Porco, J. SpitaleAbstract:We report the discovery of several large "propeller" moons in the Outer Part of Saturn's A ring, objects large enough to be followed over the 5 year duration of the Cassini mission. These are the first objects ever discovered that can be tracked as individual moons, but do not orbit in empty space. We infer sizes up to 1-2 km for the unseen moonlets at the center of the propeller-shaped structures, though many structural and photometric properties of propeller structures remain unclear. Finally, we demonstrate that some propellers undergo sustained non-Keplerian orbit motion.
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physical characteristics and non keplerian orbital motion of propeller moons embedded in saturn s rings
arXiv: Earth and Planetary Astrophysics, 2010Co-Authors: Matthew S. Tiscareno, Joseph A. Burns, K. Beurle, Matthew M. Hedman, Nicholas J. Cooper, Anthony J. Milano, M. W. Evans, Carolyn C. Porco, M Sremcevic, J. SpitaleAbstract:We report the discovery of several large "propeller" moons in the Outer Part of Saturn's A ring, objects large enough to be followed over the 5-year duration of the Cassini mission. These are the first objects ever discovered that can be tracked as individual moons, but do not orbit in empty space. We infer sizes up to 1--2 km for the unseen moonlets at the center of the propeller-shaped structures, though many structural and photometric properties of propeller structures remain unclear. Finally, we demonstrate that some propellers undergo sustained non-keplerian orbit motion. (Note: This arXiv version of the paper contains supplementary tables that were left out of the ApJL version due to lack of space).
