11 resultados para Z

em Biblioteca Digital da Produção Intelectual da Universidade de São Paulo


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Aim. The purpose of this study was to provide normal values for maximum phonation time (MPT) and the s/z ratio by examining 1660 children aged 4-12 years and without vocal signs or symptoms. Methods. The technique was based on the sustained emission of the /a/ vowel and fricatives /s/ and /z/. Results. The average of the MPT in children of the different age groups was as follows: 6.09 seconds for the age group 4-6 years (males, 5.97; female, 6.21 seconds), 7.94 seconds for the age group 7-9 years (males, 8.07; females, 7.79 seconds), and 8.98 for the age group 10-12 years (males, 9.05; females, 8.92 seconds). The overall average for males was 7.78 and females 7.64 seconds. The s/z ratio was near 1.0 in most children but above 1.2 in 133 children and below 0.8 in 133 children. Conclusion. These values of MPT and s/z ratio can be used as normative in further pediatric studies.

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The ( Z)-4,4,4-trifluoro-3-(2-hydroxyethylamino)-1-(2-hydroxyphenyl)-2-buten-1-one (C12H12F3NO3) compound was thoroughly studied by IR, Raman, UV-visible, and C-13 and F-19 NMR spectroscopies. The solid-state molecular structure was determined by X-ray diffraction methods. It crystallizes in the P2(1)/c space group with a = 12.1420(4) angstrom, b = 7.8210(3) angstrom, c := 13.8970(5) angstrom, beta = 116.162(2)degrees, and Z = 4 molecules per unit cell. The molecule shows a nearly planar molecular skeleton, favored by intramolecular OH center dot center dot center dot 0 and NH center dot center dot center dot 0 bonds, which are arranged in the lattice as an OH center dot center dot center dot 0 bonded polymer coiled around crystallographic 2-fold screw-axes. The three postulated tautomers were evaluated using quantum chemical calculations. The lowest energy tautomer (I) calculated with density functional theory methods agrees with the observed crystal structure. The structural and conformational properties are discussed considering the effect of the intra- and intermolecular hydrogen bond interactions.

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Let G = Z(pk) be a cyclic group of prime power order and let V and W be orthogonal representations of G with V-G = W-G = W-G = {0}. Let S(V) be the sphere of V and suppose f: S(V) -> W is a G-equivariant mapping. We give an estimate for the dimension of the set f(-1){0} in terms of V and W. This extends the Bourgin-Yang version of the Borsuk-Ulam theorem to this class of groups. Using this estimate, we also estimate the size of the G-coincidences set of a continuous map from S(V) into a real vector space W'.

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Excited states of the N = Z = 33 nucleus As-66 have been populated in a fusion-evaporation reaction and studied using gamma-ray spectroscopic techniques. Special emphasis was put into the search for candidates for the T = 1 states. A new 3(+) isomer has been observed with a lifetime of 1.1(3) ns. This is believed to be the predicted oblate shape isomer. The excited levels are discussed in terms of the shell model and of the complex excited Vampir approaches. Coulomb energy differences are determined from the comparison of the T = 1 states with their analog partners. The unusual behavior of the Coulomb energy differences in the A = 70 mass region is explained through different shape components (oblate and prolate) within the members of the same isospin multiplets. This breaking of the isospin symmetry is attributed to the correlations induced by the Coulomb interaction.

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LHC searches for supersymmetry currently focus on strongly produced sparticles, which are copiously produced if gluinos and squarks have masses of a few hundred GeV. However, in supersymmetric models with heavy scalars, as favored by the decoupling solution to the SUSY flavor and CP problems, and m((g) over tilde) greater than or similar to 500 GeV as indicated by recent LHC results, chargino-neutralino ((W) over tilde (+/-)(1)(Z) over tilde (2)) production is the dominant cross section for m((W) over tilde1) similar to m((Z) over tilde2) < m(<(g)over tilde>)/3 at LHC with root s = 7 TeV (LHC7). Furthermore, if m((Z) over tilde1) + (m (Z) over tilde) less than or similar to m((Z) over tilde2) less than or similar to m((Z) over tilde1) + m(h), then (Z) over tilde (2) dominantly decays via (Z) over tilde (2) -> (Z) over tilde (1)Z, while (W) over tilde (1) decays via (W) over tilde (1) -> (Z) over tilde W-1. We investigate the LHC7 reach in the W Z + (sic)T channel (for both leptonic and hadronic decays of the W boson) in models with and without the assumption of gaugino mass universality. In the case of the mSUGRA/CMSSM model with heavy squark masses, the LHC7 discovery reach in the W Z+ (sic)T channel becomes competetive with the reach in the canonical (sic)T + jets channel for integrated luminosities similar to 30 fb(-1). We also present the LHC7 reach for a simplified model with arbitrary m((Z) over tilde1) and m((W) over tilde1) similar to m((Z) over tilde2). Here, we find a reach of up to m((W) over tilde1) similar to 200 (250) GeV for 10 (30) fb(-1).

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Background: The six-minute-walk-test (6MWT) has been increasingly used in cystic fibrosis (CF) patients. However, few studies in children have correlated 6MWT with current parameters used to evaluate CF severity. Moreover, no study transformed the values of distance walked from meters into Z scores to avoid bias like age and gender, which are sources of 6MWT variability. Methods: A cross-sectional descriptive study was performed to analyze the correlations (Spearman) among forced expiratory volume in one second (FEV1), body mass index (BMI), chest radiography (CXR), chest tomography (CT), and 6MWT Z score (Z-6MWT). Clinically stable CF patients, aged 6-21 years, were included. Results: 34 patients, 14F/20M, mean age 12.1 +/- 4.0 years were studied. The mean Z-6MWT was -1.1 +/- 1.106. The following correlations versus Z-6MWT were found: FEV1 (r=0.59, r(2)=0.32, p=0.0002), BMI Z score (r=0.42, r(2)=0.17, p=0.013), CXR (r=0.34, r(2)=0.15, p=0.0472) and CT (r=-0.45, r(2)=0.23, p=0.0073). Conclusions: In conclusion there was a significant, but poor, correlation between the six minute walk test Z score and the cystic fibrosis severity markers currently in use. (C) 2011 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.

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We consider a two-parameter family of Z(2) gauge theories on a lattice discretization T(M) of a three-manifold M and its relation to topological field theories. Familiar models such as the spin-gauge model are curves on a parameter space Gamma. We show that there is a region Gamma(0) subset of Gamma where the partition function and the expectation value h < W-R(gamma)> i of the Wilson loop can be exactly computed. Depending on the point of Gamma(0), the model behaves as topological or quasi-topological. The partition function is, up to a scaling factor, a topological number of M. The Wilson loop on the other hand, does not depend on the topology of gamma. However, for a subset of Gamma(0), < W-R(gamma)> depends on the size of gamma and follows a discrete version of an area law. At the zero temperature limit, the spin-gauge model approaches the topological and the quasi-topological regions depending on the sign of the coupling constant.

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We investigate the occurrence of the optical Kerr effect and two-photon absorption when an oil-based magnetic Fe3O4 nanoparticles colloidal suspension is illuminated with high intensity femtosecond laser pulses. The frequency of the pulses is controlled and the Z-scan technique is employed in our measurements of the nonlinear optical Kerr coefficient (n(2)) and two-photon absorption coefficient (beta). From these values it was possible to calculate the real and imaginary parts of the third-order susceptibility. We observed that increasing the pulse frequency, additional physical processes take place, increasing artificially the absolute values of n(2) and beta. The experimental conditions are discussed to assure the obtention of reliable values of these nonlinear optical parameters, which may be useful in all-optical switching and optical power limiting applications. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4723829]

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Modifications in low-density lipoprotein (LDL) have emerged as a major pathogenic factor of atherosclerosis, which is the main cause of morbidity and mortality in the western world. Measurements of the heat diffusivity of human LDL solutions in their native and in vitro oxidized states are presented by using the Z-Scan (ZS) technique. Other complementary techniques were used to obtain the physical parameters necessary to interpret the optical results, e. g., pycnometry, refractometry, calorimetry, and spectrophotometry, and to understand the oxidation phase of LDL particles. To determine the sample's thermal diffusivity using the thermal lens model, an iterative one-parameter fitting method is proposed which takes into account several characteristic ZS time-dependent and the position-dependent transmittance measurements. Results show that the thermal diffusivity increases as a function of the LDL oxidation degree, which can be explained by the increase of the hydroperoxides production due to the oxidation process. The oxidation products go from one LDL to another, disseminating the oxidation process and caring the heat across the sample. This phenomenon leads to a quick thermal homogenization of the sample, avoiding the formation of the thermal lens in highly oxidized LDL solutions. (C) 2012 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.JBO.17.10.105003]

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In this study we investigate the singlet excited state absorption of lutetium bisphthalocyanine (LuPc2) over a wide spectral range. It was observed distinct nonlinear absorption behaviors; saturable (SA) and reverse saturable absorption (RSA). The RSA effect was observed below 640 and above 680 nm, while SA occurs around the Q-band region, located around 660 nm. To describe the main singlet-singlet transitions, we employed the rate equation model considering the simplified three-energy level diagram. Our results reveal a ratio between excited and ground state absorption smaller than 0.05 at the Q-band region, and of approximately 4 for the other regions. (C) 2012 Elsevier B.V. All rights reserved.

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We use the QCD sum rules to study the recently observed charmonium-like structure Z+ c (3900) as a tetraquark state. We evaluate the three-point function and extract the coupling constants of the Z+ c J/ψ π+, Z+ c ηc ρ+ and Z+ c D+ ¯D∗0 vertices and the corresponding decay widths in these channels. The results obtained are in good agreement with the experimental data and supports to the tetraquark picture of this state.