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In order to assess the moisture content of wood chips on an industrial scale, readily applicable techniques are required. Thus, near infrared (NIR) spectroscopy was used to estimate moisture in wood chips by means of partial least squares regressions. NIR spectra were obtained in spectrometer with an integrating sphere and optical fiber probe, on the longitudinal and transverse surface of Eucalyptus wood chips. The specimens had their masses and NIR spectra measured in 10 steps during drying from saturated to anhydrous condition. Principal Component Analysis was performed to explore the effect of moisture of wood chip on NIR signatures. The values of moisture content of chips were associated with the respective NIR spectra by Partial Least Squares Regression (PLS-R) and Partial Least Squares Discriminant Analysis (PLS-DA) to estimate the moisture content of wood chips and its moisture classes, respectively. Model developed from spectra recorded on the longitudinal face by the integrating sphere method presented statistics slightly better (R²cv = 0,96; RMSEcv = 7,15 %) than model based on optical fiber probe (R²cv = 0,90; RMSEcv = 11,86 %). This study suggests that for calibration of robust predictive model for estimating moisture content in chips the spectra should be recorded on the longitudinal surface of wood using the integrating sphere acquisition method.

This paper presents a portable quantitative method for the on-site determination of uric acid in urine using surface-enhanced Raman spectroscopy (SERS) and gold nanoparticle-coated paper as a substrate. A procedure was developed for the rapid preparation of cost-effective SERS substrates that enabled the adequate control of a homogeneous active area and the use of small quantities of gold nanoparticles per substrate. The standard addition method and multivariate curve resolution-alternating least squares (MCR-ALS) were applied to compensate for the matrix effect and to address overlapping bands between uric acid and interference SERS spectra. The proposed methodology demonstrated better performance than conventional univariate methods (in terms of linearity, accuracy and precision), a wide linear range (0-3.5 mmol L(-1)) and an adequate limit of detection (0.11 mmol L(-1)). For the first time, a portable SERS method coupled with chemometrics was developed for the routine analysis of uric acid at clinically relevant concentrations with minimal sample preparation and easy extension for the on-site determination of other biomarkers in complex sample matrices.

The objective of this study was to analyze the behavior of Brazilian paper companies in the international market. The analysis was based on the New Empirical Industrial Organization, based on Bresnahan's model (1982) to measure the conduct parameter in the industry. Two-Stage Least Squares (2SLS) method was used for the simultaneous equations estimative. From the results, it cannot be stated that the Brazilian companies behave as a monopolist or as a company in perfect competition in the international market. The parameter of 0.22 in the industry conduct indicated that the market is an oligopoly, intermediary to both extreme behaviors. RESUMO Neste trabalho, buscou-se analisar o comportamento das empresas brasileiras de papel no mercado mundial. A análise foi baseada na Nova Organização Industrial Empírica, conforme modelo proposto por Bresnahan (1982), para mensuração do parâmetro de conduta na indústria. Utilizou-se o método de Mínimos Quadrados em Dois Estágios (MQ2E) na estimativa das equações simultâneas. Pelos resultados, não se pode afirmar que as firmas brasileiras no mercado internacional apresentam comportamento de monopólio ou concorrência perfeita. O parâmetro de 0,22 de conduta da indústria indicou que o mercado é um oligopólio, intermediário nos dois extremos de conduta.