156 resultados para Definite integrals
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The purpose of this paper is to show certain links between univariate interpolation by algebraic polynomials and the representation of polyharmonic functions. This allows us to construct cubature formulae for multivariate functions having highest order of precision with respect to the class of polyharmonic functions. We obtain a Gauss type cubature formula that uses ℳ values of linear functional (integrals over hyperspheres) and is exact for all 2ℳ-harmonic functions, and consequently, for all algebraic polynomials of n variables of degree 4ℳ - 1.
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Neonatal administration of monosodium glutamate (MSG) in rats causes definite neuroendocrine disturbances which lead to alterations in many organ systems. The possibility that MSG could affect tooth and salivary gland physiology was examined in this paper. Male and female pups were injected subcutaneously with MSG (4 mg/g BW) once a day at the 2nd, 4th, 6th, 8th and 10th day after birth. Control animals were injected with saline, following the same schedule. Lower incisor eruption was determined between the 4th and the 10th postnatal days, and the eruption rate was measured between the 43rd and the 67th days of age. Pilocarpine-stimulated salivary flow was measured at 3 months of age; protein and amylase contents were thereby determined. The animals treated with MSG showed significant reductions in the salivary flow (males, -27%; females, -40%) and in the weight of submandibular glands (about -12%). Body weight reduction was only about 7% for males, and did not vary in females. Saliva of MSG-treated rats had increased concentrations of total proteins and amylase activity. The eruption of lower incisors occurred earlier in MSG-treated rats than in the control group, but on the other hand the eruption rate was significantly slowed down. The incisor microhardness was found to be lower than that of control rats. Our results show that neonatal MSG treatment causes well-defined oral disturbances in adulthood in rats, including salivary flow reduction, which coexisted with unaltered protein synthesis, and disturbances of dental mineralization and eruption. These data support the view that some MSG-sensitive hypothalamic nuclei have an important modulatory effect on the factors which determine caries susceptibility.
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In the light-cone gauge choice for Abelian and non-Abelian gauge fields, the vector boson propagator carries in it an additional spurious or unphysical pole intrinsic to the choice requiring a careful mathematical treatment. Research in this field over the years has shown us that mathematical consistency only is not enough to guarantee physically meaningful results. Whatever the prescription invoked to handle such an object, it has to preserve causality in the process. On the other hand, the covariantization technique is a well-suited one to tackle gauge-dependent poles in the Feynman integrals, dispensing the use of ad hoc prescriptions. In this work we show that the covariantization technique in the light-cone gauge is a direct consequence of the canonical quantization of the theory. © World Scientific Publishing Company.
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In this work we solve exactly a class of three-body propagators for the most general quadratic interactions in the coordinates, for arbitrary masses and couplings. This is done both for the constant as the time-dependent couplings and masses, by using the Feynman path integral formalism. Finally, the energy spectrum and the eigenfunctions are recovered from the propagators. © 2005 Elsevier Inc. All rights reserved.
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OBJECTIVE: This study evaluated the efficiency of repolishing, sealing with surface sealant, and the joining of both in decreasing the surface roughness of resin-based composites after a toothbrushing process. METHOD AND MATERIALS: Ten specimens of each composite (Alert, Z100, Definite, and Prodigy Condensable), measuring 2 mm in thickness and 4 mm in diameter, were made and submitted to finishing and polishing processes on both sides of the specimens using the Sof-Lex system. The specimens were then subjected to toothbrushing (30,000 cycles), and surface roughness (Ra) was analyzed with a Surfcorder SE 1700 profilometer. The upper surface of each composite was etched with 37% phosphoric acid, and the surface-penetrating sealant Protect-it was applied on 1 surface. The roughness of these surfaces was again measured. On the other side, the surface of the specimen was repolished, and the efficiency of this procedure was measured using the profilometer. The surface roughness resulting from the joining of the 2 methods was verified by applying, in the final stage, the surface-penetrating sealant on the repolished surface. Data were analyzed with analysis of variance and Tukey test (P <.05). RESULTS: Results showed that the lowest surface roughness values were obtained for Definite, Z100, and Prodigy Condensable after the repolishing process and after the repolishing plus sealing. For Alert, the joining of repolishing plus sealing promoted the lowest values of surface roughness. CONCLUSION: Of the resin-based composites, Alert demonstrated the highest values of surface roughness in all the techniques tested.
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The aim of the study was to assess risk factors for vascular dementia (VaD) in elderly psychiatric outpatients without dementia, and to determine to what extent clinical interventions targeted such risk factors. Out of 250 clinical charts, 78 were selected of patients over 60 years old, who showed no signs of dementia. Information was obtained regarding demographics, clinical conditions (diagnosis according to ICD-10), complementary investigation, cognitive functions (via CAMCOG), neuroimaging, and the presence of risk factors for VaD. Depression was the most prevalent psychiatric disorder (74%). A great majority of the patients (86%) had at least one risk factor for VaD. One-third of the sample showed three or more risk factors for VaD. The clinical conditions related to risk factors for VaD were hypertension (48.7%), heart disease (30.8%), hypercholesterolemia (25.6%), diabetes mellitus (23.1%), stroke (12.8%), tryglyceride (12.8%), and obesity (5.1%). In terms of lifestyle, smoking (19.2%), alcohol abuse (16.7%), and sedentarism (14.1%) were other risk factors found. Definite risk factors for VaD were found in 83.3% of the patients. Previous interventions targeting risk factors were found in only 20% of the cases. The high rates of risk factors for VaD identified in this sample suggest that psychiatrists should be more attentive to these factors for the prevention of VaD. © 2007 Elsevier B.V. All rights reserved.
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Among other things, the pure spinor formalism has been used to rederive some particular superstring scattering amplitudes in the last few years. I will briefly review how the computations were done and show that the kinematical factors of these amplitudes can be simply written as integrals in a pure spinor superspace. © 2007 Elsevier B.V. All rights reserved.
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Plesiomonas shigelloides is a Gram-negative rod-shaped bacterium, of the family Enterobacteriaceae, which has been isolated from freshwater and salt water, freshwater fish, shellfish and many species of animals. Most human P. shigelloides infections are suspected to be waterborne. The organism can be found in untreated water used as drinking water, in recreational water, or in water used to rinse food that is consumed without cooking or heating. The ingestion of P. shigelloides does not always cause illness in the host animal, and the organism may be present temporarily as a transient, noninfectious member of the intestinal flora. It has been isolated from the stools of patients with diarrhea,but it is also sometimes isolated from healthy individuals. P. shigelloides has been implicated in gastroenteritis, usually a self-limiting disease characterized by fever, chills, abdominal pain, nausea, diarrhea or vomiting; in severe cases the diarrhea may be yellowish-green, foamy and tinged with blood. The bacteria may also cause extra-intestinal infection. Furthermore, it can produce toxins and may be invasive. The evidence in favor of considering P. shigelloides as an enteropathogen is not totally convincing. Although it has been isolated from patients with diarrhea and incriminated in some outbreaks involving contaminated water and food, it was not possible, in many P. shigelloides samples associated with gastrointestinal infections, to identify a definite mechanism of virulence.
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Using the results recently obtained for computing integrals over (non-minimal) pure spinor superspace, we compute the coefficient of the massless two-loop four-point amplitude from first principles. Contrasting with the mathematical difficulties in the RNS formalism where unknown normalizations of chiral determinant formulæ force the two-loop coefficient to be determined only indirectly through factorization, the computation in the pure spinor formalism can be smoothly carried out. © SISSA 2010.
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Mesenteric torsion is a rare disease in dogs whereas it is more common to affect large animals. The main clinical signs observed are acute, such as prostration and abdominal distension which evolve to a state of shock and death. This paper reports the mesenteric torsion in a dog that was presented to veterinary care with generalized acute abdominal pain of sudden onset. At the physical examination, signs of acute abdomen, rectal temperature of 35 oC, moderate dehydration, congested mucous membrane, and prostration were detected. Emergency therapy was instituted and radiographic and ultrasound examinations were requested. The radiography showed increase in the bowel diameter and an image suggestive of intussusception. The patient was referred to emergency exploratory laparotomy and obtained a definite diagnosis of ileocolic intussusception associated to mesenteric torsion. Due to the extent of intestinal dysfunction, the patient was euthanized on the operating table.
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Risk factors for development of multiple sclerosis (MS) are still a matter of debate. Latitude gradient, vitamin D deficiency and season of birth are among the most investigated environmental factors associated with the disease. Several international studies suggest that birth in spring is a substantial risk factor for MS. We investigated the season of birth as a potential risk for MS in different geographical regions of Brazil. We conducted a cross-sectional retrospective study with 2257 clinically definite MS patients enrolled in 13 Brazilian MS clinics in the south, southeast, and northeast regions of Brazil. Demographic and clinical data relating to date of birth and clinical features of the disease were collected and analysed, and subsequently compared with birth date among the general Brazilian population. The distribution of date of birth of MS patients showed an increase in spring and a decrease in autumn, with no difference being observed in the other seasons. In conclusion, season of birth is a probable risk factor for MS in most parts of Brazil. These findings may be related to the role that vitamin D plays in MS pathogenesis. © 2013 Elsevier B.V. All rights reserved.
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Given a strongly regular Hankel matrix, and its associated sequence of moments which defines a quasi-definite moment linear functional, we study the perturbation of a fixed moment, i.e., a perturbation of one antidiagonal of the Hankel matrix. We define a linear functional whose action results in such a perturbation and establish necessary and sufficient conditions in order to preserve the quasi-definite character. A relation between the corresponding sequences of orthogonal polynomials is obtained, as well as the asymptotic behavior of their zeros. We also study the invariance of the Laguerre-Hahn class of linear functionals under such perturbation, and determine its relation with the so-called canonical linear spectral transformations. © 2013 Elsevier Ltd. All rights reserved.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)