971 resultados para INTRANUCLEAR CASCADE CALCULATION
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Diabetic individuals are more susceptible to infections and this seems to be related to impaired phagocyte function. Alveolar macrophages (AMs) are the first barrier to prevent respiratory infections Leukotrienes (LTs) increase AM phagocytic activity via Fc gamma R. In this study, we compared AMs from diabetic and nondiabetic rats for phagocytosis via Fc gamma R and the roles of LTs and insulin Diabetes was induced in male Wistar rats by alloxan (42 mg/kg, i.v); macrophages were obtained by bronchoalveolar lavage and IgG-opsonised sheep red blood cells (IgG-SRBC) were used as targets. LTs were added to the AMs 5 min before the addition of IgG-SRBC. AMs were treated with a LT synthesis inhibitor (zileuton, 10 mu M), or antagonists of the LTB(4) receptor (CP105 696, 10 mu M) cys-LT receptor (MK571, 10 mu M), 30 or 20 min before the addition of IgG-SRBC, respectively. We found that the phagocytosis of IgG-SRBC by AMs from diabetic rats is impaired compared with non-diabetic rats. Treatment with the LT inhibitor/antagonists significantly reduced AM phagocytosis in non-diabetic but not diabetic rats. During the phagocytosis of IgG-SRBC LTB(4) and LTC(4) were produced by AMs from both groups. The addition of exogenous LTB(4) or LTD(4) potentiated phagocytosis similarly in both groups Phagocytosis was followed by the phosphorylation of PKC-delta. ERK and Akt This was reduced by zileuton treatment in AMs from non-diabetic but not diabetic rats The addition of insulin to AMs further increased the phagocytosis by increasing PKC-delta phosphorylation These results suggest that the impaired phagocytosis found in AMs from diabetic rats is related to a deficient coupling of LTs to the Fc gamma R signaling cascade and that insulin has a key role in this coupling An essential role for insulin in Innate immunity is suggested (C) 2010 Elsevier Ltd. All rights reserved.
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We use the QCD sum rules to evaluate the mass of a possible scalar mesonic state that couples to a molecular D(s)*(D) over bar (s)* current. We find a mass m(Ds)*(Ds)* = (4.14 +/- 0.09) GeV, which is in an excellent agreement with the recently observed Y(4140) charmonium state. We consider the contributions of condensates up to dimension-eight, we work at leading order in alpha(s) and we keep terms which are linear in the strange quark mass m(s). We also consider a molecular D*(D) over bar* current and we obtain m m(D)*(D)* = (4.13 +/- 0.10), around 200 MeV above the mass of the Y(3930) charmonium state. We conclude that it is possible to describe the Y(4140) structure as a D(s)*(D) over bar (s)* molecular state or even as a mixture of D(s)*(D) over bar (s)* and D*(D) over bar* molecular states. (C) 2009 Elsevier B.V. All rights reserved.
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Using the QCD sum rules we test if the charmonium-like structure Y(4274), observed in the J/psi phi invariant mass spectrum, can be described with a D(s)(D) over bar (s0)(2317)+ h.c. molecular current with J(PC) = 0(-+). We consider the contributions of condensates up to dimension ten and we work at leading order in alpha(s). We keep terms which are linear in the strange quark mass m(s). The mass obtained for such state is mD(s)D(s0) = (4.78 +/- 0.54) GeV. We also consider a molecular 0(-+) D (D) over bar (0)(2400)+ h.c. current and we obtain m(DD0) = (4.55 +/- 0.49) GeV. Our study shows that the newly observed Y(4274) in the J/psi phi invariant mass spectrum can be, considering the uncertainties, described using a molecular charmonium current. (C) 2011 Elsevier B.V. All rights reserved.
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We apply a self-energy-corrected local density approximation (LDA) to obtain corrected bulk band gaps and to study the band offsets of AlAs grown on GaAs (AlAs/GaAs). We also investigate the Al(x)Ga(1-x)As/GaAs alloy interface, commonly employed in band gap engineering. The calculations are fully ab initio, with no adjustable parameters or experimental input, and at a computational cost comparable to traditional LDA. Our results are in good agreement with experimental values and other theoretical studies. Copyright (C) EPLA, 2011
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The metastable phase diagram of the BCC-based ordering equilibria in the Fe-Al-Mo system has been calculated via a truncated cluster expansion, through the combination of Full-Potential-Linear augmented Plane Wave (FP-LAPW) electronic structure calculations and of Cluster Variation Method (CVM) thermodynamic calculations in the irregular tetrahedron approximation. Four isothermal sections at 1750 K, 2000 K, 2250 K and 2500 K are calculated and correlated with recently published experimental data on the system. The results confirm that the critical temperature for the order-disorder equilibrium between Fe(3)Al-D0(3) and FeAl-B2 is increased by Mo additions, while the critical temperature for the FeAl-B2/A2 equilibrium is kept approximately invariant with increasing Mo contents. The stabilization of the Al-rich A2 phase in equilibrium with overstoichiometric B2-(Fe,Mo)Al is also consistent with the attribution of the A2 structure to the tau(2) phase, stable at high temperatures in overstoichiometric B2-FeAl. (C) 2009 Elsevier Ltd. All rights reserved.
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In order to validate the Geant4 toolkit for dosimetry applications, simulations were performed to calculate conversion coefficients h(10, alpha) from air kerma free-in-air to personal dose equivalent Hp(10, a). The simulations consisted of two parts: the production of X-rays with radiation qualities of narrow and wide spectra, and the interaction of radiation with ICRU tissue-equivalent and ISO water slab phantoms. The half-value layers of the X-ray spectra obtained by simulation were compared with experimental results. Mean energy, spectral resolution, half-value layers and conversion coefficients were compared with ISO reference values. The good agreement between results from simulation and reference data shows that the Geant4 is suitable for dosimetry applications which involve photons with energies in the range of ten to a few hundreds of keV. (C) 2008 Elsevier Ltd. All rights reserved.
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The protective shielding design of a mammography facility requires the knowledge of the scattered radiation by the patient and image receptor components. The shape and intensity of secondary x-ray beams depend on the kVp applied to the x-ray tube, target/filter combination, primary x-ray field size, and scattering angle. Currently, shielding calculations for mammography facilities are performed based on scatter fraction data for Mo/Mo target/filter, even though modern mammography equipment is designed with different anode/filter combinations. In this work we present scatter fraction data evaluated based on the x-ray spectra produced by a Mo/Mo, Mo/Rh and W/Rh target/filter, for 25, 30 and 35 kV tube voltages and scattering angles between 30 and 165 degrees. Three mammography phantoms were irradiated and the scattered radiation was measured with a CdZnTe detector. The primary x-ray spectra were computed with a semiempirical model based on the air kerma and HVL measured with an ionization chamber. The results point out that the scatter fraction values are higher for W/Rh than for Mo/Mo and Mo/Rh, although the primary and scattered air kerma are lower for W/Rh than for Mo/Mo and Mo/Rh target/filter combinations. The scatter fractions computed in this work were applied in a shielding design calculation in order to evaluate shielding requirements for each of these target/filter combinations. Besides, shielding requirements have been evaluated converting the scattered air kerma from mGy/week to mSv/week adopting initially a conversion coefficient from air kerma to effective dose as 1 Sv/Gy and then a mean conversion coefficient specific for the x-ray beam considered. Results show that the thickest barrier should be provided for Mo/Mo target/filter combination. They also point out that the use of the conversion coefficient from air kerma to effective dose as 1 Sv/Gy is conservatively high in the mammography energy range and overestimate the barrier thickness. (c) 2008 American Association of Physicists in Medicine.
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Far-infrared transitions in polar semiconductors are known to be affected by the presence of shallow donor impurities, external magnetic fields and the electron-LO-phonon interaction. We calculate the magnetodonor states in indium phosphide by a diagonalization procedure, and introduce the electron-phonon interaction by the Frohlich term. The main effects of this perturbation are calculated by a multi-level version of the Wigner-Brillouin theory. We determine the transition energies, from the ground state to excited states, and find good qualitative agreement with recently reported absorption-spectroscopy measurements in the 100-800 cm(-1) range, with applied magnetic fields up to 30 T. Our calculations suggest that experimental peak splittings in the 400-450 cm(-1) range are due to the electron-phonon interaction.
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In this paper we present a new wavelet-based algorithm for low-cost computation of the cepstrum. It can be used for real time precise pitch determination in automatic speech and speaker recognition systems. Many wavelet families are examined to determine the one that works best. The results confirm the efficacy and accuracy of the proposed technique for pitch extraction. (C) 2008 Elsevier B.V. All rights reserved.
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This paper focuses on the study of cascade heat pump systems in combination with solar thermal for the production of hot water and space heating in single family houses with relatively high heating demand. The system concept was developed by Ratiotherm GmbH and simulated with TRNSYS 17. The basic cascade system uses the heat pump and solar collectors in parallel operation while a further development is the inclusion of an intermediate store that enables the possibility of serial/parallel operation and the use of low temperature solar heat. Parametric studies in terms of compressor size, refrigerant pair and size of intermediate heat exchanger were carried out for the optimization of the basic system. The system configurations were simulated for the complete year and compared to a reference of a solar thermal system combined with an air source heat pump. The results show ~13% savings in electricity use for all three cascade systems compared to the reference. However, the complexity of the systems is different and thus higher capital costs are expected.
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The Cascade Mountain Range in Washington State is the site of several active volcanoes that have the potential to erupt which would deeply affect the lives of those who live near them. This study explores the hazard areas associated with the five largest volcanoes in the region: Mt. Baker, Glacier Peak, Mt. Rainier, Mt. Adams and Mt. St. Helens. It was determined which geographic regions would be affected by tephra, pyroclastic blasts and lahar flows and the associated populations that live in each of these areas. The level of emergency preparedness necessary for a volcanic eruption could be better determined based on the findings of this study.
Welfare costs of inflation when interest-bearing deposits are disregarded: a calculation of the bias
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Most estimates of the welfare costs of in ation are devised considering only noninterest- bearing assets, ignoring that since the 80s technological innovations and new regulations have increased the liquidity of interest-bearing deposits. We investigate the resulting bias. Suscient and necessary conditions on its sign are presented, along with closed-form expressions for its magnitude. Two examples dealing with bidimensional bilogarithmic money demands show that disregarding interest-bearing monies may lead to a non-negligible overestimation of the welfare costs of in ation. An intuitive explanation is that such assets may partially make up for the decreased demand of noninterest-bearing assets due to higher in ation.
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Numerical cognition is based on two components - number processing and calculation. Its development is influenced by biological, cognitive, educational, and cultural factors. The objectives of the present study were to: i) assess number processing and calculation in Brazilian children aged 7-12 years from public schools using the Zareki-R (Battery of neuropsychological tests for number processing and calculation in children, Revised; von Aster & Dellatolas, 2006) in order to obtain normative data for Portuguese speakers; ii) identify how environment, age, and gender influences the development of these mathematical skills; iii) investigate the construct validity of the Zareki-R by the contrast with the Arithmetic subtest of WISC-III. The sample included 172 children, both genders, divided in two groups: urban (N= 119) and rural (N= 53) assessed by the Zareki-R. Rural children presented lower scores in one aspect of number processing; children aged 7-8 years demonstrated an inferior global score than older; boys presented a superior performance in both number processing and calculation. Construct validity of Zareki-R was demonstrated by high to moderate correlations with Arithmetic subtest of WISC-III. The Zareki-R therefore is a suitable instrument to assess the development of mathematical skills, which is influenced by factors such as environment, age, and gender.