Indoor NO2 air pollution and lung function of professional cooks

Studies of cooking-generated NO2 effects are rare in occupational epidemiology. In the present study, we evaluated the lung function of professional cooks exposed to NO2 in hospital kitchens. We performed spirometry in 37 cooks working in four hospital kitchens and estimated the predicted FVC, FEV1 and FEF25-75, based on age, sex, race, weight, and height, according to Knudson standards. NO2 measurements were obtained for 4 consecutive days during 4 different periods at 20-day intervals in each kitchen. Measurements were performed inside and outside the kitchens, simultaneously using Palm diffusion tubes. A time/exposure indicator was defined as representative of the cumulative exposure of each cook. No statistically significant effect of NO2 exposure on FVC was found. Each year of work as a cook corresponded to a decrease in predicted FEV1 of 2.5% (P = 0.046) for the group as a whole. When smoking status and asthma were included in the analysis the effect of time/exposure decreased about 10% and lost statistical significance. on predicted FEF25-75, a decrease of 3.5% (P = 0.035) was observed for the same group and the inclusion of controllers for smoking status and asthma did not affect the effects of time/exposure on pulmonary function parameter. After a 10-year period of work as cooks the participants of the study may present decreases in both predicted FEV1 and FEF25-75 that can reach 20 and 30%, respectively. The present study showed small but statistically significant adverse effects of gas stove exposure on the lung function of professional cooks.

Association between diastolic blood pressure and cumulative work time

A pressão arterial diastólica foi analisada enquanto indicador genérico de envelhecimento, e sua associação com o tempo de serviço foi estudada após o controle da idade como possível fator de confundimento. O estudo foi realizado entre operários de um curtume brasileiro em julho de 1993. Foi testada a associação entre pressão diastólica e tempo de serviço, ajustando um modelo de regressão linear de segunda ordem, em que a pressão diastólica era função da idade e do tempo de serviço do operário. Ao ajustar o modelo, pode-se prever que, no início do trabalho no curtume, em média, cada período de um ano está associado com um aumento de cerca de 1,5 mmHg na pressão diastólica. O ajuste obtido realça um componente diretamente associado ao trabalho como parte do coeficiente de aumento da pressão no grupo estudado. Esse componente é o dobro daquele diretamente associado com a idade.

Estimation of (co)variance components and genetic parameters for weights of red-winged tinamou using random regression models

Com este trabalho objetivou-se determinar parâmetros genéticos para peso corporal de perdizes em cativeiro. Foram utilizados modelos de regressão aleatória na análise dos dados considerando os efeitos genéticos aditivos diretos (AD) e de ambiente permanente de animal (AP) como aleatórios. As variâncias residuais foram modeladas utilizando-se funções de variância de ordem 5. A curva média da população foi ajustada por polinômios ortogonais de Legendre de ordem 6. Os efeitos genéticos aditivos diretos e de ambiente permanente de animal foram modelados utilizando-se polinômios de Legendre de segunda a nona ordem. Os melhores resultados foram obtidos pelos modelos de ordem 6 de ajuste para os efeitos genéticos aditivos diretos e de ordem 3 para os de ambiente permanente pelo Critério de Informação de Akaike e ordem 3 para ambos os efeitos pelos Critério de Informação Bayesiano de Schwartz e Teste de Razão de Verossimilhança. As herdabilidades estimadas variaram de 0,02 a 0,57. O primeiro autovalor respondeu por 94 e 90% da variação decorrente de efeitos aditivos diretos e de ambiente permanente, respectivamente. A seleção de perdizes para peso corporal é mais efetiva a partir de 112 dias de idade.

Binding energies of excitons trapped by ionized donors in semiconductors

Using the hyperspherical adiabatic approach in a coupled-channel calculation, we present precise binding energies of excitons trapped by impurity donors in semiconductors within the effective-mass approximation. Energies for such three-body systems are presented as a function of the relative electron-hole mass sigma in the range 1 less than or equal to1/sigma less than or equal to6, where the Born-Oppenheimer approach is not efficiently applicable. The hyperspherical approach leads to precise energies using the intuitive picture of potential curves and nonadiabatic couplings in an ab initio procedure. We also present an estimation for a critical value of sigma (sigma (crit)) for which no bound state can be found. Comparisons are given with results of prior work by other authors.

THE PARTITION-FUNCTION FOR AN ANYON-LIKE OSCILLATOR

We compute the partition function of an anyon-like harmonic oscillator. The well known results for both the bosonic and fermionic oscillators are then re-obtained as particular cases of our function. The technique we employ is a non-relativistic version of the Green function method used in the computation of one-loop effective actions of quantum field theory.

Drying of persimmon: Mathematical model for diffusivity as a simultaneous function of moisture content and shrinkage

Fresh persimmon has a high moisture content (about 85% wet basis) making it highly perishable and requiring adequate drying conditions to obtain an acceptable dehydrated product. Drying kinetics of persimmon cv. Rama Forte was studied in a fixed bed dryer at temperatures ranging from 50 to 80 degreesC and air velocity of 0.8 m/s. Shrinkage during drying was described by a linear correlation with respect to water content. Evaluation of effective diffusivity as a function of moisture content, with undergoing shrinkage during drying was based on Fourier series solution of Fick's diffusion equation. Effective diffusivity values at moisture contents between 0.09 - 4.23 kg water/kg dry matter were found to be in the range of 2.6 x 10(-10) m(2)/s to 5.4 x 10(-10) m(2)/s, and its dependence on air drying temperature was represented by an Arrhenius type equation. Activation energy increased with decreasing water content in persimmons.

Concentration profiles and effective diffusion coefficients of sucrose and water in osmo-dehydrated apples

The spatial distribution of water and sugars in half-fresh apples dehydrated in sucrose solutions (30% and 50% w/w, 27 degrees C) for 2, 4 and 8 h, was determined. Each half was sliced as from the exposed surface. The density, water and sugar contents were determined for each piece. A mathematical model was fitted to the experimental data of the water and sucrose contents considering the overall flux and tissue shrinkage. A numerical method of finite differences permitted the calculation of the effective diffusion coefficients as a function of concentration, using material coordinates and integrating the two differential equations (for water and sucrose) simultaneously. The coefficients obtained were one or even two orders of magnitude lower than those for pure solutions and presented unusual concentration dependence. The behaviour of the apple tissue was also studied using light microscopy techniques to obtain images of the osmotically treated pieces (20%, 30% and 50% w/w sucrose solutions for 2, 4 and 8 h). (c) 2006 Elsevier Ltd. All rights reserved.

Error function approximations of interest in electrochemistry.

The error function is present in several equations describing eletrode processes. But, only approximations of this function are used. In this work, these and other approximations are studied and evaluated according to precision.

Logarithmic barrier-augmented Lagrangian function to the optimal power flow problem

This paper presents a new approach to solve the Optimal Power Flow problem. This approach considers the application of logarithmic barrier method to voltage magnitude and tap-changing transformer variables and the other constraints are treated by augmented Lagrangian method. Numerical test results are presented, showing the effective performance of this algorithm. (C) 2005 Elsevier Ltd. All rights reserved.

Enhancement of natural killer cell function by titanocenes in mice bearing Ehrlich ascites tumour

In the present work, we studied the effects of two titanocenes, biscyclopentadienyidichlorotitanium IV, (DDCT) and its derivative, biscyclopentadienylditiocianatetitanium IV (BCDT), on the activity of natural killer (NK) cells in Ehrlich ascites tumour (EAT)-bearing BALB/c mice. In order to investigate a more direct effect of these compounds on NK cell function, we performed experiments with severe combined immunodeficiency (SCID) mice, which exhibit a normal NK cell response in the absence of T and B cells. The treatment consisted of intraperitoneal (i.p.) administration of 15 mg/kg/day of DDCT for 2 days or 10 mg/kg/day of BCDT for 3 days. In addition, to verify whether the effects produced by the titanocenes were compound specific or related to a direct antitumour effect, we also investigated the effects of a 3-day treatment with 100 mg/kg of cyclophosphamide cyclophosphamide on NK cell activity. Our results demonstrated that, in BALB/c and SCID mice, NK cell function declined to subnormal levels after inoculation of the tumour. In these animals, although treatment with DDCT and BCDT significantly enhanced NK cell function, only DDCT restored NK cell activity to normal values in all stages studied. Conversely, treatment with cyclophosphamide reduced NK cell function in nontumour bearing SCID mice and was also unable to restore the decreased NK activity of tumour-bearing SCID mice, thus demonstrating that the enhancement of NK cell function by titanocenes is compound specific. The same effect of cyclophosphamide was observed with BALB/c mice. In the present study, the up-modulatory effects of these two compounds on NK cell function reveal a new aspect of the mechanism of antitumoural action of titanocenes. (C) 2003 Elsevier B.V. All rights reserved.

Study of bronchoalveolar lavage fluid in paracoccidioidomycosis: cytopathology and alveolar macrophage function in response to gamma interferon; comparison with blood monocytes

Patients with paracoccidioidomycosis (PCM) present marked involvement of the lungs during the course of the mycosis. The purpose of this work was to obtain bronchoalveolar lavage (BAL) fluid from these patients to study the cytopathology, TNF levels and the oxidative and fungicidal response of alveolar macrophages (AMs) to in vitro incubation with recombinant IFN-gamma. To compare the lung and blood compartments, these determinations were also made in plasma and blood monocytes (BMs) obtained from the same patients. The cytopathology of BAL fluid revealed a predominance of macrophages, but with the presence of neurrophil exudation, and rare lymphocytes and epithelioid and giant cells. Comparison of the oxidative status and fungicidal activity of AMs and circulating BMs demonstrated that both cell types are highly activated for these two functions when compared to control cells. However, TNF levels were higher in BAL fluid than in plasma. The possible mechanisms involved in the hyperresponsiveness of cells from PCM patients are discussed. (C) 2003 Editions scientifiques et medicales Elsevier SAS. All rights reserved.

Bound states of the Dirac equation for a class of effective quadratic plus inversely quadratic potentials

The Dirac equation is exactly solved for a pseudoscalar linear plus Coulomb-like potential in a two-dimensional world. This sort of potential gives rise to an effective quadratic plus inversely quadratic potential in a Sturm-Liouville problem, regardless the sign of the parameter of the linear potential, in sharp contrast with the Schrodinger case. The generalized Dirac oscillator already analyzed in a previous work is obtained as a particular case. (C) 2004 Elsevier B.V. All rights reserved.

Revisiting the S-matrix approach to the open superstring low energy effective lagrangian

The conventional S-matrix approach to the (tree level) open string low energy effective lagrangian assumes that, in order to obtain all its bosonic alpha'(N) order terms, it is necessary to know the open string (tree level) (N + 2)-point amplitude of massless bosons, at least expanded at that order in alpha'. In this work we clarify that the previous claim is indeed valid for the bosonic open string, but for the supersymmetric one the situation is much more better than that: there are constraints in the kinematical bosonic terms of the amplitude (probably due to Spacetime Supersymmetry) such that a much lower open superstring n-point amplitude is needed to find all the alpha'(N) order terms. In this 'revisited' S-matrix approach we have checked that, at least up to alpha'(4) order, using these kinematical constraints and only the known open superstring 4-point amplitude, it is possible to determine all the bosonic terms of the low energy effective lagrangian. The sort of results that we obtain seem to agree completely with the ones achieved by the method of BPS configurations, proposed about ten years ago. By means of the KLT relations, our results can be mapped to the NS-NS sector of the low energy effective lagrangian of the type II string theories implying that there one can also find kinematical constraints in the N -point amplitudes and that important informations can be inferred, at least up to alpha'(4) order, by only using the (tree level) 4-point amplitude.

Magnetic-field and confinement effects on the effective Land, g factor in AlxGa1-xAs parabolic quantum wells

The magnetic-field and confinement effects on the Land, factor in AlxGa1-xAs parabolic quantum wells under magnetic fields applied parallel or perpendicular to the growth direction are theoretically studied. Calculations are performed in the limit of low temperatures and low electron density in the heterostructure. The g factor is obtained by taking into account the effects of non-parabolicity and anisotropy of the conduction band through the 2 x 2 Ogg-McCombe Hamiltonian, and by including the cubic Dresselhaus spin-orbit term. A simple formula describing the magnetic-field dependence of the effective Land, factor is analytically derived by using the Rayleigh-Schrodinger perturbation theory, and it is found in good agreement with previous experimental studies devoted to understand the behavior of the g factor, as a function of an applied magnetic field, in semiconductor heterostructures. Present numerical results for the effective Land, factor are shown as functions of the quantum-well parameters and magnetic-field strength, and compared with available experimental measurements.

Optimization of Radial Basis Function neural network employed for prediction of surface roughness in hard turning process using Taguchi's orthogonal arrays

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)