963 resultados para elliptic curve cryptography
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Statement of problem. To select the width of denture teeth, the distance between the marks indicating the location of the canines is usually measured around the curvature of the wax occlusal rim; however, most manufacturers' mold charts provide the measurements of the artificial 6 anterior teeth as if they were on a straight line.Purpose. The purpose of this study was to investigate whether the curve distance between the distal surfaces of the maxillary canines can be related to the combined width (straight measurement) of the 6 anterior teeth in 4 ethnic groups.Material and methods. Maxillary stone casts were obtained for 160 dentate subjects of 4 ethnic groups (40 whites, 40 blacks, 40 multiracial - descendants of white and black parents, and 40 Asians). The width of each maxillary anterior tooth was measured on the casts with sliding calipers. The combined width of the 6 anterior teeth (CW) corresponded to the sum of the width of each anterior tooth. The curve distance between the distal surfaces of the canines (CD) was measured by using dental tape and sliding calipers. The Pearson correlation coefficient and regression analysis were used to evaluate the relationship between CD and CW in each ethnic group (alpha=.05).Results. The mean CD and CW values (in mm) obtained were: whites (CD=52.12; CW=45.65); blacks (CD=56.10; CW=48.13); multiracial (CD=53.58; CW=46.54); and Asians (CD=53.29; CW=46.60). Significant (P<.001) correlations between CD and CW measurements were observed for all ethnic groups studied (whites, r=0.957; blacks, r=0.803; multiracial, r=0.917; and Asians, r=0.881). The following linear regression equations were obtained: whites [CD=1.1(CW)+0.3]; blacks [CD=0.95(CW)+9.3]; multiracial [CD=1.2(CW)-1.1]; and Asians [CD=1.0(CW)+5].Conclusions. The curve distance between the distal surfaces of the maxillary canines can be accurately related to the combined width of the 6 anterior teeth in the selection of denture teeth for the studied ethnic groups. (J Prosthet Dent 2012;107:400-404)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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O conhecimento das fases de absorção de água das diferentes espécies é importante em pesquisas objetivando melhorar a qualidade das sementes, utilizando tratamentos como condicionamento osmótico, pré-hidratação e uso de bioreguladores. O objetivo do presente trabalho foi estabelecer uma metodologia para determinar o limite entre a primeira e a segunda fase do processo, considerando o modelo W = f(t) - (a - w0)exp(-kt), utilizando testes estatísticos. O limite entre as duas primeiras fases do processo de absorção de água pelas sementes, foi determinado utilizando-se a distribuição assintótica de uma função de estimadores. O ponto a partir do qual esta diferença (W*) deixa de ser significativa foi determinado utilizando-se o teste estatístico T de Student. Para os dados utilizados como exemplo, tem-se o modelo ou =(0,434 + 0,00162 t) - (0,434 - w o)exp(-0,121 t), com r² = 0,98 e W* = (0,434 - w o) exp(-0,121 t). O valor de t encontrado (27,2 horas) é menor do que o valor determinado, considerando-se como critério para mudança de fase a diferença de 1% entre a assíntota e o valor estimado pelo modelo ajustado. Essa diferença de duas horas corresponde a 0,28% de água absorvida.
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Thin films of perovskite-type materials such as PbTiO3, BaTiO3, (Pb,La)TiO3, (Pb, La)(ZrTi)O-3, KNbO3, and Pb(Mg,Nb)03 have been attracting great interest for applications like non-volatile memories, ultrasonic sensors and optical devices. Thin film should be epitaxially grown or at least highly textured since the properties of this anisotropic material depend on the crystallographic orientation. For optical devices, in particular, an epitaxial thin film without defects are essential to reduce optical propagation losses. Pb1-xLaxTiO3 (PLT) where x=0, 13 and 27% thin films were prepared by a chemical method (polymeric precursors method), and deposited by the spin coating technique onto substrates of SrTiO3 (STO) and LaAlO3 (LAO). The films were then beat treated at 500 degrees C in a controlled atmosphere of 0,. The orientation degree of the thin films was obtained from rocking curve technique, by means of X-ray difftaction analysis. A microstructural study revealed that the films were crack-free, homogeneous and have low roughness. (c) 2006 Elsevier B.V. All rights reserved.
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The caprine oxyhemoglobin dissociation curve has not been previously defined. Blood from 10 healthy goats was equilibrated in a tonometer with calibrated gas mixtures of oxygen at concentrations of 95%, 21%, 13%, 12%, 10%, 9%, 8%, 5%, 4% and 2.5%, 5% carbon dioxide, balance nitrogen. The pH, partial pressure of oxygen (PO2), partial pressure of carbon dioxide (PCO2), total hemoglobin, oxyhemoglobin saturation, carboxyhemoglobin, methemoglobin, and oxygen content were measured. The PO2/oxyhemoglobin and the PO2/oxygen content relationships were graphed with curve-fitting software and a formula for calculating oxyhemoglobin from PO2 was generated. The maximum oxygen content per gram of hemoglobin was 1.29 ml of oxygen per gram of hemoglobin. The PO2 at which hemoglobin was 50% saturated (P-50) from the PO2/oxyhemoglobin relationship was 28.6 +/- 1.5 mmHg and that from the PO2/oxygen content relationships was 29.1 +/- 1.6 mmHg. The Hill coefficient for the PO2/oxyhemoglobin data was 3.0 +/- 0.4. (c) 2005 Elsevier Ltd. All rights reserved.
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In the present work, we expanded the study done by Solorzanol(1) including the eccentricity of the perturbing body. The assumptions used to develop the single-averaged analytical model are the same ones of the restricted elliptic three-body problem. The disturbing function was expanded in Legendre polynomials up to fourth-order. After that, the equations of motion are obtained from the planetary equations and we performed a set of numerical simulations. Different initial eccentricities for the perturbing and perturbed body are considered. The results obtained perform an analysis of the stability of a near-circular orbits and investigate under which conditions this orbit remain near-circular.
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The polymer surface degradation and/or modification evolution of Teflon FEP and Mylar C films caused by a low energy electron beam were analyzed using a new method that consists in measuring the second crossover energy shift in the electronic emission curve. Upon prolonged irradiation, the second crossover energy shifts irreversibly to lower values in Teflon FEP but to higher values in Mylar C, indicating distinct mechanisms of surface degradation for the two polymers. The method represents a relatively inexpensive way to monitor early stages of surface degradation since the secondary electron emission comes from a maximum depth below the geometric surface of 100 mn in insulators. (C) 2001 Elsevier B.V. Ltd. All rights reserved.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)