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The activimeter calibration has the purpose of ensure greater reliability in measurement results, hence the activimeters used are commonly installed in controlled areas and, in some cases, with difficult access. The activimeter “in situ” calibration methodology presented in this work allows its execution only with the displacement of the radioactive samples and not of the activimeter itself, which simplifies the procedure of nuclear medicine services and at radiopharmaceuticals production centers, without affecting the quality and accuracy of measurements. After the application of the methodology by qualified technicians, the obtained results of the tested activimeters showed its importance since the calibration factors can present correction of up to 5% for 111In and greater than 5% for 123I.

ABSTRACT Surface runoff monitoring is important for the sustainable management of global water resources. Obtaining a practical and inexpensive method for collecting data in the field can help to better understand surface runoff and its effects, necessary for the management of watersheds. This study sought to elaborate the calibration curves of the ultrasonic sensor due to temperature variability, verifying the inaccuracy of the distance between objects and the sensor, and determining the feasibility of using low-cost sensors in an in-loco experiment installed on Parshall flumes. The experiment was conducted on the Experimental Farm of the Federal University of Grande Dourados, Dourados, MS, Brazil. The data were collected by twelve HC-SR04 ultrasonic distance sensors , which were coupled to a data acquisition system composed of an expansion board connected to a Raspberry minicomputer. Sensor calibration using temperature data resulted in the error correction of ± 8.0 mm of distance reading. On the other hand, the R2 of the comparison curves between sensor and control system (laser distance meter and ruler in the flume) resulted in high values (above 0.95), showing the feasibility of its use and meeting the specifications for use in the field subject to weather conditions. This study demonstrates the performance of ultrasonic sensors as a potential for new application to evaluate surface runoff aiming to propose new runoff coefficients.

Hailstorms are hazardous for people and goods. Automatically collecting information on hailstorms will help climate researchers analyze them and generate models for forecasting. Reproducing hail impacts is a requisite for designing and calibrating an electronic hail sensor. In this article, the design of a device for hail-impact simulation is presented. This device is based on the theory of Energy Matching, which explains how steel balls can be used instead of hailstones in order to have equivalent impact energies. The posed device, which can perform up to fourteen impacts between loading instances, either by dropping balls one by one or in pairs, was constructed. The size of the balls can be between 0.5 cm and 3.0 cm. In this paper, which is an extension of the work originally presented at the URUCON2021 conference, the importance of having such a hail-impact simulation device is explained. The main contribution of this extended work is the presentation of an experiment performed as an application of the constructed device. This experiment has the objective of verifying the aiming repetitiveness, while also verifying the linear relation between impact and electric signal energies.

The extremity dosimeters are devices used to quantifying the radiation dose that the occupationally exposed individual receives in specific regions of the body during the work time. Dosimeter calibration is essential so that the dosimeter response is equivalent to the received dose. Tests such as batch homogeneity and lower detection limit are part of the dosimeter calibration process. The rod phantom simulates the region of interest regarding the interaction with radiation and the scattered dose. The extremity dosimeters used were the LiF:Mg,Ti thermoluminescent dosimeters.

The provision for the Brazilian Army of equipment that provides reliable and safe measurements, enabling decision-making based on radioprotection parameters, leads to the need to investigate the metrology of the calibration system used in the Radiation Monitor Calibration Laboratory (LabCal) of the Institute of Chemical, Biological, Radiological and Nuclear Defense (IDQBRN). To this end, the commissioning in cesium-137 is of primary importance in this process. In order to check the conformity of the radiator system, in this work, the ambient dose equivalent rate, , was obtained experimentally for several configurations to compare them with the appropriate theoretical concepts. For this, the distance between the source of Cesium-137 (36.9 GBq in 01/22/2015) and the ionization chamber was varied from 500 to 3000 mm at 250mm intervals. To obtain lower ambient dose equivalent rates, 15 and 32 mm thick lead attenuators were used. The mathematical model that best fit the experimental values was analyzed. In all cases, the potential function offers better fit, since the coefficients of determination obtained are approximately equal to 1, obeying the Law of the Inverse Square of the Distance, according to theoretical foundation. Moreover, it was evaluated that the relative deviations are below the limits established by the relevant standard.

The aim of this work is to estimate and analyze the measurement uncertainty in the calibration of liquid flow meters by the gravimetric method, which is a primary method. The calibration system used in this work is the calibration system for liquid flow meters of the National Institute of Metrology Quality and Technology -INMETRO that gives traceability to liquid flow meters in Brazil. The system that was fully operated manually went through an automation process in some of the components. The measurements were made in five ranges for a mass meter and the uncertainty expression followed the procedures of the Guide to the Expression of Uncertainty in Measurement (Iso-Gum). The results were compared with each other and showed the performance of the meters according to the technology used in the measurement and the consistency of the calibration system.

Phantoms can be used as quality control objects in computed tomography (CT) imaging and dosimetry in specific regions of interest. By means of phantom tests, alternatives can be created to optimize the acquisition protocols and thus modify the acquisition parameters to deposit lower levels of radiation to the patient, seeking a quality image for the diagnosis. Radiochromic films, GAFCHROMIC XR-AQ2 model, are used to measure the dose-response when exposed to radiation. The profile of the absorbed dose within a phantom is important because it allows an understanding of a larger reality. Calibration curves were obtained from radiochromic films using a cylindrical phantom made of polymethyl methacrylate (PMMA). This phantom has five openings, one central and four peripherals lagged 90°. The phantom was positioned in the isocenter of the gantry of a scanner manufactured by the Toshiba, model Asterion, using 120 and 135 kV voltage of the X-ray tube. The phantom peripheral openings were positioned similarly to positions 3, 6, 9, and 12 of the analog clock. The ionization chamber was used for the record values of the Air Kerma in PMMA, in the central and 12 positions when the central slice of the phantom was irradiated in the axial mode. The other openings were filled with rods also made of PMMA. Radiochromic film strips were placed into PMMA rods and the central and 12 openings were filled. The central area of the phantom was scanned in helical mode. The film strips were digitized and processed their images to have the calibration curve survey.

ABSTRACT: Among the soil constituents, special attention is given to soil organic matter (SOM) and clay contents, since, among other aspects, they are key factors to nutrient retention and soil aggregates formation, which directly affect the crop production potential. The methods commonly used for the quantification of these constituents have some disadvantages, such as the use of chemical reactants and waste generation. An alternative to these methods is the near-infrared spectroscopy (NIRS) technique. The aim of this research is to evaluate models for SOM and clay quantification in soil samples using spectral data by NIRS. A set (n = 400) of soil samples previously analyzed by traditional methods were used to generate a NIRS calibration curve. The clay content was determined by the hydrometer method while SOM content was determined by sulfochromic solution. For calibration, we used the original spectra (absorbance) and spectral pretreatment (Savitzky-Golay smoothing derivative) in the following models: multiple linear regression (MLR), partial last squares regression (PLSR), support vector machine (SVM) and Gaussian process regression (GPR). The curve validation was performed with the SVM model (best performance in the calibration based on R² and RMSE) in two ways: with 40 random samples from the calibration set and another set with 200 new unknown samples. The soil clay content affects the predictive ability of the calibration curve to estimate SOM content by NIRS. Validation curves showed poorer performance (lower R² and higher RMSE) when generated from unknown samples, where the model tends to overestimate the lower levels and to underestimate the higher levels of clay and SOM. Despite the potential of NIRS technique to predict these attributes, further calibration studies are still needed to use this technique in soil analysis laboratories.

Abstract: The objective of this work was to perform a sensitivity analysis of the main input parameters required for the AquaCrop water balance model, using biomass and grain yield data of a rainfed-simulated corn crop, obtained along the climate data series of 1987-2016 in the South of Brazil. The levels of soil-water stress and the depths of maximum effective rooting were the input parameters that most affected the biomass and grain yields simulated by the model, followed by the crop coefficient, water-use efficiency, soil water storage capacity, and contribution of groundwater to water availability in the root zone. The parameters crop cycle duration, plant density, pattern of soil-water extraction, and field surface practices showed little or no impact on the final results. AquaCrop is a robust water balance model, with small or moderate general sensitivity to variations of the main input parameter values, which makes it applicable to situations with field data limitations.

This article presents an implementation of the transmission/reflection line method to determine the intrinsic electromagnetic properties of unknown materials with relative magentic permeability not equal to one. With a vector network analyser (VNA) the forwardand back-scattered energy are measured to simultaneously extract the electric permittivity and magenetic permeability. The classic Nicolson-Ross-Weir extraction technique in frequency domain is explained in detail and presented such that the equations can be easily implemented by open-source post-processing with GNU Octave. The shift in phase reference planes and connector calibration measurements are performed such that a very low-cost VNA without de-embedding function can be used. A coaxial transmission line with N type female connectors is used providing a low-cost, easy to manufacture solution of a sample holder. The measurement procedure is valid from 2 MHz to 6 GHz, whereas the preliminary results are shown in the GHz range from 1 to 6 GHz. The article also comments on the sample preparation especially the thickness of the material slab.

ABSTRACT The lack of hydrological data in Brazil is the main limitation for structuring hydrological models, which are able to assist water resources management. Therefore, studies are needed to evaluate the performance of models without on-site calibration. Within this context, the aim of this study was to calibrate the SWAT hydrological model for the Camanducaia River Basin and to evaluate the performance of this calibration in a contiguous drainage basin, one of the Jaguarí River. For the calibration and validation steps, the SWAT-CUP program was utilized. Uncertainty analysis and calculation of efficiency indexes were carried out through the SUFI-2 algorithm. The SWAT adjustment in the Camanducaia River Basin obtained adequate results, with a Nash-Sutcliffe coefficient higher than 0.80 in the monthly time step and of 0.64 for the daily time step. With the parametrical transfer of this model to the Jaguarí River Basin, simulations were classified as very good in the monthly time step and acceptable for the daily time step. Based on these results, it can be concluded that the parametric transfer is a promising technique to model ungauged catchments, and can contribute towards water resources management in the river basins of the Mantiqueira Range region, as well as in other regions with shortage of hydrological monitoring.

Iodine-131 (131I) has been used for diagnosis and therapy in Nuclear Medicine Centers in Brazil for more than 50 years. The present study aims to investigate the impact of the counts density and the reconstruction parameters in the calibration factor determination and in the image quantification, considering the reality of Brazilian dosimetry studies. For this task, images were quantified using calibration images with high and low counts density and reconstructed adopting two different parameters approaches, usually employed in patients images. SPECT quantification results presented in this work follow other previous 131I SPECT studies and suggest that, due to the long time interval between the first e last image, as required by the Brazilian guideline, the image quantification accuracy can be improved if the counts density in calibration measurements is considered.

Diameter at breast height (DBH) is the simplest, most common and most important tree dimension in forest inventory and is closely correlated with wood volume, height and biomass. In this study, a number of linear and nonlinear models predicting diameter at breast height from stump diameter were developed and evaluated for Oriental beech (Fagus orientalisLipsky) stands located in the forest region of Ayancık, in the northeast of Turkey. A set of 1,501 pairs of diameter at breast height-stump measurements, originating from 70 sample plots of even-aged Oriental beech stands, were used in this study. About 80 % of the otal data (1,160 trees in 55 sample plots) was used to fit a number of linear and nonlinear model parameters; the remaining 341 trees in 15 sample plots were randomly reserved for model validation and calibration response. The power model data set was found to produce the most satisfactory fits with the Adjusted Coefficient of Determination, R2adj (0.990), Root Mean Square Error, RMSE (1.25), Akaike’s Information Criterion, AIC (3820.5), Schwarz’s Bayesian Information Criterion, BIC (3837.2), and Absolute Bias (1.25). The nonlinear mixed-effect modeling approach for power model with R2adj(0.993), AIC (3598), BIC (3610.1), Absolute Bias (0.73) and RMSE (1.04) provided much better fitting and precise predictions for DBH from stump diameter than the conventional nonlinear fixed effect model structures for this model. The calibration response including tree DBH and stump diameter measurements of the four largest trees in a calibrated sample plot in calibration produced the highest Bias, -5.31 %, and RMSE, -6.30 %, the greatest reduction percentage.

ABSTRACT Hydrodynamic models are important tools for simulating river water level and flow. A considerable fraction of the hydrodynamic model errors are related to parameters uncertainties. As cross sections bottom levels considerably affect water level simulation, this parameter has to be well estimated for flood studies. Automatic calibration performance and processing time depend on the search space dimension, which is related to the number of calibrated parameters. This paper shows the application of the Shuffled Complex Evolution (SCE-UA) optimization algorithm to assess the number of cross sections bottom levels used in calibration. Also was evaluated the extent of algorithm exploration regarding computational processing time and accuracy. It was tested the calibration of 2, 4, 7 and 10 cross sections bottom levels (2PAR, 4PAR, 7PAR and 10PAR calibration configurations) of a 1,100 km reach of the Madeira River. 7PAR and 10PAR representation had better fitness (lower objective function value) on cross sections used for calibration; however, the error on other cross sections (2 validation gauging stations) was higher than 2PAR and 4PAR calibration. The short number (5) of gauging stations used in calibration has limited the number of calibrated parameters to represent adequately the river level profile. Finally, this paper shows a contribution for the parsimonious selection of parameters regarding the spatial distribution of observation sites used in calibration.

Hydrological models are important tools that have been used in water resource planning and management. Thus, the aim of this work was to calibrate and validate in a daily time scale, the SWAT model (Soil and Water Assessment Tool) to the watershed of the Galo creek , located in Espírito Santo State. To conduct the study we used georeferenced maps of relief, soil type and use, in addition to historical daily time series of basin climate and flow. In modeling were used time series corresponding to the periods Jan 1, 1995 to Dec 31, 2000 and Jan 1, 2001 to Dec 20, 2003 for calibration and validation, respectively. Model performance evaluation was done using the Nash-Sutcliffe coefficient (E NS) and the percentage of bias (P BIAS). SWAT evaluation was also done in the simulation of the following hydrological variables: maximum and minimum annual daily flowsand minimum reference flows, Q90 and Q95, based on mean absolute error. E NS and P BIAS were, respectively, 0.65 and 7.2% and 0.70 and 14.1%, for calibration and validation, indicating a satisfactory performance for the model. SWAT adequately simulated minimum annual daily flow and the reference flows, Q90 and Q95; it was not suitable in the simulation of maximum annual daily flows.

The conventional curriculum of Analytical Chemistry undergraduate courses emphasizes the introduction of techniques, methods and procedures used for instrumental analysis. All these concepts must be integrated into a sound conceptual framework to allow students to make appropriate decisions. Method calibration is one of the most critical parameters that has to be grasped since most analytical techniques depend on it for quantitative analysis. The conceptual understanding of calibration is not trivial for undergraduate students. External calibration is widely discussed during instrumental analysis courses. However, the understanding of the limitations of external calibration to correct some systematic errors is not directly derived from laboratory examples. The conceptual understanding of other calibration methods (standard addition, matrix matching, and internal standard) is imperative. The aim of this work is to present a simple experiment using grains (beans, corn and chickpeas) to explore different types of calibration methods.

This article shows a working method using CAD and free software to do the calibration process for a conventional digital camera to correct the distortion produced by the lens. It will continue with the 3D restitution of the main geometric elements of the projection, and finally, the spatial geometric reconstruction of the elements of interest appearing in the photo, without needing of topographical support. It will be also shown a method to make the integration of the three-dimensional model on the photograph of the environment in which the building will be constructed, so that, if it’s seen from the appropriate point of view, it will be perfectly integrated in the place of photography where it really should be, which is extremely useful when showing an architectural project.

A equação de Penman-Monteith FAO-56 (EToPM) tem sido recomendada pela FAO, Organização para a Alimentação e Agricultura das Nações Unidas (ONU), como padrão para estimar a evapotranspiração de referência (ETo). Essa equação requer muitas variáveis que não estão disponíveis na maioria das estações meteorológicas no Brasil central. Por outro lado, a equação de Hargreaves é considerada simples e demanda somente dados de temperatura máxima e mínima para estimar a ETo. Entretanto, essa equação requer um ajuste local. Esse estudo analisa a possibilidade de utilizar a equação de Hargreaves ajustada para estimar a ETo no estado de Goiás. Para isso, os parâmetros empíricos, HC (coeficiente empírico de Hargreaves) e HE (expoente empírico de Hargreaves), da equação de Hargreaves foram ajustados considerando dois processos, ajuste local (HGR - Hargreaves ajuste local) e ajuste regional (HGL - Hargreaves ajuste regional). Para o HGL, os parâmetros empíricos foram ajustados para cada estação meteorológica. Já, para o HGR, os parâmetros empíricos foram ajustados considerando conjuntamente os dados de todas as estações meteorológicas. A equação de Hargreaves ajustada para ambos os processos, local e regional, apresentou valores de ERQM de 17,95 e 21,93%, respectivamente, considerando o conjunto total de dados climáticos. A equação de Hargreaves ajustada localmente ou regionalmente é uma opção para estimar os valores diários de ETo no Estado de Goiás em locais em que a disponibilidade de dados climáticos é limitada.The FAO-56 Penman-Monteith equation (EToPM) has been recommended by the Food and Agriculture Organization (FAO) of the United Nations as the standard equation for estimating reference evapotranspiration (ETo). The FAO-56 PM equation requires numerous weather data that are not available in most of the stations of Brazil central. On the other hand, the Hargreaves equation is a more simple equation for estimating ETo, and demands only maximum and minimum temperature data. However, this equation requires local calibration. This paper examines the potential of using the Hargreaves equation adjusted to estimate the ETo in Goiás State. For this, the Hargreaves empiric parameters, HC (empirical Hargreaves coefficient) and HE (empirical Hargreaves exponent), were adjusted considering two procedures, local adjustment (HGL - Hargreaves local adjustment) and regional adjustment (HGR - Hargreaves regional adjustment). For HGL, the adjustment of empiric parameters was done for each weather station. For HGR, the adjustment of empiric parameters was done considering the data set of all weather stations. The Hargreaves equation adjusted by both processes, local and regional, showed values of 17.95 and 21.93% for ERQM respectively, considering the full range of climatic data. The Hargreaves equation adjusted by both processes is an option to estimate the daily values of ETo in Goiás State where there are available data limitation.

OBJETIVO: Comparar dois métodos de calibração da pletismografia respiratória por indutância (PRI) em três posturas diferentes. MÉTODOS: Foram avaliados 28 indivíduos saudáveis (18 mulheres e 10 homens), com média de idade de 25,4 ± 3,9 anos. Todos os indivíduos foram submetidos a isovolume maneuver calibration (ISOCAL, calibração por manobra de isovolume) e qualitative diagnostic calibration (QDC, calibração diagnóstica qualitativa) em ortostatismo, sedestação e decúbito dorsal. Foi utilizada ANOVA e a disposição gráfica de Bland-Altman para a avaliação da concordância dos métodos de calibração. RESULTADOS: Os valores da constante de proporcionalidade (K) foram significativamente distintos entre ISOCAL e QDC nas três posturas avaliadas: 1,6 ± 0,5 vs. 2,0 ± 1,2, em decúbito dorsal; 2,5 ± 0,8 vs. 0,6 ± 0,3, em sedestação; e 2,0 ± 0,8 vs. 0,6 ± 0,3, em ortostatismo (p < 0,05 para todos). CONCLUSÕES: Nossos resultados sugerem que QDC não é um método acurado para a calibração da PRI. Os valores de K obtidos por ISOCAL mostram que a PRI deve ser calibrada para cada postura avaliada.OBJECTIVE: To compare two methods of respiratory inductive plethysmography (RIP) calibration in three different positions. METHODS: We evaluated 28 healthy subjects (18 women and 10 men), with a mean age of 25.4 ± 3.9 years. For all of the subjects, isovolume maneuver calibration (ISOCAL) and qualitative diagnostic calibration (QDC) were used in the orthostatic, sitting, and supine positions. In order to evaluate the concordance between the two calibration methods, we used ANOVA and Bland-Altman plots. RESULTS: The values of the constant of proportionality (K) were significantly different between ISOCAL and QDC in the three positions evaluated: 1.6 ± 0.5 vs. 2.0 ± 1.2, in the supine position, 2.5 ± 0.8 vs. 0.6 ± 0.3 in the sitting position, and 2.0 ± 0.8 vs. 0.6 ± 0.3 in the orthostatic position (p < 0.05 for all). CONCLUSIONS: Our results suggest that QDC is an inaccurate method for the calibration of RIP. The K values obtained with ISOCAL reveal that RIP should be calibrated for each position evaluated.

The aim of this study was to verifiy the validity (criterion) and generality (cross-validity) of accelerometer thresholds to distinguish different physical activity intensities and identify sedentary behaviors in children and adolescents. A systematic literature review was conducted in Pubmed, Scopus, Sports Discus and Web of Science databases. Inclusion criteria were: a) derivation and/or validation of accelerometers thresholds related to intensity of physical activity in youth (2 to 18 years); b) use of indirect calorimetry or direct observation as reference method; c) original research article published in English, Portuguese or Spanish. Nineteen studies were selected. Accelerometers most investigated were ActiGraph, RT3 and Actical. Thresholds showed good to moderate validity in the calibration phase (sensitivity = 68 to 100%; specificity = 61 to 100%). Generalizability of the thresholds were higher when they were tested on samples (Kappa = 0.72 to 0.91; sensitivity = 79 to 94%; specificity = 72 to 98%) than in independent activities (Kappa = 0.46 to 0.71; sensitivity = 27 to 97%; specificity = 52 to 95%). One calibration study tested the validity of thresholds in samples and independent activities, and only a validation study of thresholds was found. In conclusion, limited information was found on the majority of accelerometers thresholds to monitoring physical activity of children and adolescents. Validation studies are needed to identify appropriate thresholds for each type of accelerometer.

For an accurate use of pesticide leaching models it is necessary to assess the sensitivity of input parameters. The aim of this work was to carry out sensitivity analysis of the pesticide leaching model PEARL for contrasting soil types of Dourados river watershed in the state of Mato Grosso do Sul, Brazil. Sensitivity analysis was done by carrying out many simulations with different input parameters and calculating their influence on the output values. The approach used was called one-at-a-time sensitivity analysis, which consists in varying independently input parameters one at a time and keeping all others constant with the standard scenario. Sensitivity analysis was automated using SESAN tool that was linked to the PEARL model. Results have shown that only soil characteristics influenced the simulated water flux resulting in none variation of this variable for scenarios with different pesticides and same soil. All input parameters that showed the greatest sensitivity with regard to leached pesticide are related to soil and pesticide properties. Sensitivity of all input parameters was scenario dependent, confirming the need of using more than one standard scenario for sensitivity analysis of pesticide leaching models.Para o uso confiável de simuladores da lixiviação de pesticidas, é necessária a avaliação da sensibilidade dos dados de entrada. O objetivo deste trabalho foi realizar a análise de sensibilidade do simulador da lixiviação de pesticidas PEARL para tipos de solos contrastantes da Bacia Hidrográfica do Rio Dourados, no Estado de Mato Grosso do Sul, Brasil. A análise de sensibilidade foi feita através da execução de várias simulações com dados de entrada diferentes e calculando suas influências nos resultados obtidos. O método usado foi o denominado de análise de sensibilidade "individual", onde se varia cada dado de entrada de forma independente enquanto se mantêm constantes, os outros dados de entrada, conforme cenário-padrão. A análise de sensibilidade foi automatizada, utilizando-se da ferramenta SESAN, que foi acoplada ao simulador PEARL. Resultados revelaram que somente as características do solo influenciaram nas simulações do fluxo da água e que, para cenários com diferentes pesticidas e mesmo solo, as simulações do fluxo da água não sofreram alterações. Os dados de entrada que mostraram as maiores sensibilidades com relação às simulações da lixiviação de pesticidas estão relacionados às características dos solos e pesticidas. A sensibilidade de todos os dados de entrada estudados foi dependente do tipo de cenário escolhido, confirmando a necessidade de utilizar mais de um cenário- -padrão na avaliação da sensibilidade de simuladores da lixiviação de pesticidas.

Objetivou-se com este trabalho calibrar o modelo ORYZA-APSIM e avaliar o seu desempenho na simulação do desenvolvimento, crescimento e produtividade da variedade cultivada de arroz de terras altas BRS-Primavera para as diferentes regiões produtoras dessa cultura. Na calibração foram definidas: as unidades de calor efetivo diário (HU); as taxas de desenvolvimento fenológico para cada estádio (DVR); as frações da massa de matéria seca das folhas (MSf), colmos (MS C) e órgãos armazenadores (panículas) (MSp), e os parâmetros para calcular a área foliar específica (AEF) simulada durante o ciclo da cultura. Na avaliação foram comparados os valores simulados com os observados do desenvolvimento fenológico (número de dias da emergência ao florescimento) e do crescimento da cultura (massa de matéria seca total da parte aérea (MSt) índice de área foliar (IAF)) e a produtividade (P). O modelo apresentou desempenho satisfatório na simulação do desenvolvimento fenológico para regiões próximas ao da calibração. Para latitudes próximas ao equador, como Teresina, PI, o desempenho fenológico foi insatisfatório. Para o crescimento, nos dois experimentos, o índice de área foliar (IAF) simulado diferiu do observado, e a MSt simulada foi semelhante a observada, mas diferiu entre o florescimento e a maturidade fisiológica. A MSf simulada foi satisfatória no primeiro experimento e regular no segundo. Isso é devido ao modelo superestimar os efeitos da deficiência hídrica que ocorreram durante a condução do segundo experimento. Entretanto, o modelo ORYZA-APSIM apresentou bom desempenho na simulação da ordem de produtividade ao nível de significância de 5%.This study was carried out with the purpose of calibranting the ORYZA-APSIM crop model and evaluating its performance to simulate the development, growth and yield of upland rice variety BRS-Primavera in the production area of upland rice in Brazil. Acording to the following variables: the effective heat daily units (HU); the rates of phenological development at each stage (DVR); the fractions of the dry matter of leaves (DMf), stems, storage organs (panicle) (DMp) and parameters to define the specific leaf area (SLA) during the crop cycle. For the evaluation, it was compared the values simulated and observed for phenological development (number of days from emergence to flowering) and for growth (total dry matter of shoot (DMt), dry matter of green leaves (DMf), leaf area index (LAI)) and yield (P). The model showed a satisfactory performance to simulate the phenological development for regions near the local calibration. For latitude near equator, Teresina-PI, the phenological simulation was poor. The simulated growth for leaf area index (LAI) differed from observed, but the simulated total dry matter was similar to observed in the first experiment and not so good in the second experiment. One of the reasons is that the model overestimates the effects of water stress during the experiment. However, the ORYZA-APSIM presented good performance in simulation of the order of productivity at the 5% level of significance.

This study evaluated the performance of two carbon analyzer catalyzers, one with high sensitivity and another with regular sensitivity, used in the determination of carbon concentration in a total organic carbon analyzer – TOC. Its applicability was then evaluated in an environmental monitoring study. They have been constructed two calibration curves with 5 points each, first in the interval of 2 mgL-1 at 10 mgL-1 and the second in the interval of 10 mgL-1 at 100 mgL-1. Both calibration curves showed a high level of linearity that can be observed by R2 values that were 0.9996 for the concentration range of 2 mgL-1 to 10 mgL-1, 0.9999 for the concentration range of 10 mgL-1 to 100 mgL-1, and 0.9999 for the concentration range of 100 mgL-1 to 1.000 mgL-1. The limits of detection and quantification for inorganic carbon were, respectively, 0.003 mgL-1 and 0.009 mgL-1. The limits of detection and quantification for the different catalyzers were also evaluated and showed the following values: regular sensitivity: 0.015 mgL-1 and 0.050 mgL-1, respectively, and high sensitivity; 0.004 mgL-1 and 0.013 mgL-1, respectively. The environmental monitoring was performed in two points (PB1 and PB2) in the Garcia stream. Carbon concentrations were monitored during 24 hours with 2-hour intervals between sampling. It was observed that the concentrations of carbon remained constant throughout the experiment, with the exception of the period between 10:00 am and 04:00 pm, probably due to the input of carbonates and bicarbonates derived from textile companies in the region or still had to the launching of urban sewers. Comparing the average carbon concentration, values of point PB2 were always higher than those observed at point PB1. In high concentration analysis, only irrelevant variations were observed with the use of both catalyzers.

Estudos que incluem medidas antropométricas exigem, além da padronização de técnicas de aferição, o emprego de métodos estatísticos para a avaliação de erros de mensuração. OBJETIVO: Comparar duas técnicas estatísticas para avaliar a calibração de entrevistadores, em treinamento para a aferição de medidas antropométricas. METODOLOGIA: Treze entrevistadores participaram da fase de treinamento, que foi programado de modo que, em cada sessão, sub-grupos de entrevistadores realizassem duas aferições de medidas de peso e duas de altura em voluntários (em média, 10 voluntários/sessão). Ao todo, foram realizadas seis sessões para a aferição das medidas de peso e onze para a aferição das medidas de altura. Para as medidas de peso foram utilizadas balanças eletrônicas e, para as de altura, estadiômetros de parede. Para avaliar a calibração, dois métodos estatísticos foram comparados: a) o coeficiente de correlação intraclasse (CCI) e b) a precisão e a exatidão das aferições, segundo Habicht. RESULTADOS: Os entrevistadores foram submetidos, em média, a duas sessões para a calibração das medidas de peso e a três sessões para a calibração das medidas de altura, sendo a precisão atingida antes da exatidão. Os valores dos respectivos CCIs indicaram medições fortemente concordantes desde a primeira sessão. CONCLUSÃO: O método de Habicht apresentou melhor desempenho que o CCI, pois, além do cálculo da precisão, indicou a magnitude da divergência das aferições realizadas pelos entrevistadores, em relação às do supervisor (exatidão).Standardized technical procedures as well as statistical methods can be used to calculate the magnitude of measurement errors in studies related to anthropometric measures. OBJECTIVE: To compare two statistical approaches to evaluate interviewers´ calibration during the training phase before data collection in an epidemiological study. METHODS: Thirteen interviewers, divided into sub-groups were trained to take two measures of weight and two of height from 10 volunteers in each training section. Training was completed in six sections for weight and eleven for height measurements. Digital scales were used to measure weight and wall stadiometers to measure height. In order to evaluate interviewers´ calibration, two statistical methods were compared: a) the Intraclass Correlation Coefficient (ICC); and b) the precision and accuracy as proposed by Habicht. RESULTS: On average, interviewers were submitted to 2 sections for weight measure calibration, and to 3 sections for height measure calibration, and precision was reached before accuracy. ICC values showed that measures were strongly correlated since the first section. CONCLUSION: The Habicht method seems to be better than ICC, given it allowed for corrections not only of interviewer discrepancies related to precision but it also calculated the magnitude of deviations between measurements of interviewers and supervisor (accuracy).

Among the indirect methods to evaluate the volumetric soil water content (?v), the Time Domain Reflectometry (TDR) technique is receiving growing attention. As any technique, it presents advantages and disadvantages: the most serious disadvantage is the calibration necessity. At the present study, values of apparent dielectric constant (Ka) and volumetric water content (?v) for a Red Latosol were obtained in a laboratory experiment, using seventeen probes of TDR, from which two were original and fifteen were manufactured by the staff. This study aimed: a) to calibrate the seventeen probes, in laboratory conditions, comparing six regression models for each probe; b) to verify the viability to use the manufactured probes. It was found out that the best regression model was the cubic polynomial model and that the manufactured probes presented performances comparable to the original ones.

An indirect calorimetry system for rapid determination of CO2 and CH4 production and O2 consumption to estimate heat production of animals was built at Escola de Veterinária da Universidade Federal de Minas Gerais, Brazil. Procedures for determination of correction and calibration factors for gas analyzers and the whole system, using standard test gases were described. In addition, a metabolic trial was performed to evaluate heat production of lambs fed ad libitum. It is concluded that the system is suitable for heat production determinations in small and medium size animals.Um sistema de calorimetria para a determinação rápida da produção de CO2 e CH4 e do consumo de O2 de animais para o cálculo da produção de calor foi construído na Escola de Veterinária da Universidade Federal de Minas Gerais. Foram descritos os procedimentos para a determinação dos fatores de correção dos analisadores e calibração do sistema utilizando-se gases padrão. Adicionalmente, um ensaio de metabolismo foi realizado para se avaliar a produção de calor de ovinos alimentados ad libitum. Conclui-se que o sistema está apto para determinações de produção de calor em animais de pequeno e médio porte.

Indoor Cycling (IC) has considerably grown at fitness centers, due to practitioners giving-up of street cycling because of security issues as well as the trainability and practicity. IC also has the potencial for helping to lose weight and cardiovascular conditioning. There are only few studies on this subject, and the main reason is thelimitation of the Indoor Cycling Bicycle (ICB), which does not either measure workload or power. Therefore, functional evaluation and adequate training prescription are limited and the solution lies on implementation of an ICB with loading system. This paper has the purpose of describing the development and calibration of an ICB that actually measures workload and power. The project was based on the adaptation of a loading system from a Monark mechanical lockwire cycloergometer (basket of weight), which measurement is considered a gold standard, on an ICB. The adaptation, for having maintaining the Monark dimensions of the Flywheel/Crown/Ratchet circuit as well as for using new materials, seems not to offer any type of limitation for prototype construct validity. The ICB also had a low cost. Therefore, this ICB can be classified as a cycloergometer. The adaptation permited to advance in this area, by both maintaining orignal ICB characteristics and also controlling for workload and power. RESUMO Tem havido uma grande busca pela modalidade de Ciclismo Indoor (CI) em academias, o que se deve ao êxodo dos praticantes de ciclismo de rua em prol de segurança, treinamento e praticidade, além do interesse pelo potencial do CI nos processos de emagrecimento e condicionamento cardiovascular. Há poucos estudosnessa área, dentre as principais causas, está à limitação da bicicleta de ciclismo indoor (BCI) que não quantifica a carga utilizada e da potência produzida. Isto tem dificultado a avaliação funcional e a prescrição adequada de treinamento. Assim, a solução é implementar a uma BCI um sistema de carga. O objetivo do estudo foi construir e calibrar uma BCI que gradue a carga utilizada e a potência produzida. A metodologia foi dividida em quatro etapas: 1) fundamentação teórica; 2) desenvolvimento do protótipo; 3) construção; e 4) calibração. O projeto baseou-se na adaptação, em uma BCI, de um sistema de carga do cicloergômetro de frenagem mecânica Monark (cesto de anilha), que mensura tais variáveis e é tido como padrão ouro. Considerações finais: a BCI por ter respeitado os fundamentos básicos do modelo de referência, por ter sido construída com materiais novos e pela manutenção das dimensões do circuito Roda-Volante/Coroa/Catraca padrão Monark, parecem impedir qualquer tipo de limitação para a possível validade de constructo do protótipo, além de ter baixo custo. Portanto, a BCI construída, por possibilitar a graduação de carga e a potência produzida, pode ser classificada como umcicloergômetro, além do que, sua geometria, fiel às características das bicicletas de CI, acabou por preencher uma lacuna existente nesta área.

Os parâmetros do "Simplified Simple Biosphere Model"-SSiB foram validados e posteriormente calibrados para os sítios de pastagem da Fazenda Nossa Senhora Aparecida (62º22'W; 10º45'S) e de floresta da Reserva Biológica do Jaru (62º22'W; 10º45'S), ambos situados no estado de Rondônia. Foram utilizadas medidas micrometeorológicas e hidrológicas obtidas durante o período seco de 2001, como parte do Experimento de Grande Escala da Biosfera-Atmosfera na Amazônia - LBA. Os resultados indicam que o modelo simulou bem o saldo de radiação, tanto na pastagem quanto na floresta. O fluxo de calor latente foi superestimado nos dois sítios nos períodos de simulação, o que deve estar relacionado aos parâmetros utilizados no cálculo dessa variável. O modelo subestimou o fluxo de calor sensível na pastagem e na floresta, principalmente no período noturno; porém, para a floresta, os valores foram mais próximos daqueles observados. Com os parâmetros ajustados, melhores estimativas dos fluxos de calor latente e de calor sensível foram geradas e, conseqüentemente, representou melhor as partições de energia na floresta e na pastagem.The parameters of the Simplified Simple Biosphere Model - SSiB were validated and subsequently calibrated for the Fazenda Nossa Senhora Aparecida (62º22'W; 10º45'S) pasture site and the Reserva Biológica do Jaru (62º22'W; 10º45'S) forest site, both located in the state of Rondônia. Micrometeorological and hydrological data collected during the dry period of 2001, as part of the Large-Scale Biosphere-Atmosphere Experiment in Amazonia - LBA, were used. The results showed that the model simulated well the net radiation, both at the pasture and at the forest. The latent heat flux was super-estimated in both sites. The model sub-estimated the sensible heat flux at the pasture and at the forest, mainly during the night period; notwithstanding, the values for the forest were nearer to the observed ones. With the calibrated parameters, the model generated better estimations of the latent and the sensible heat fluxes, thus better representing the energy partition both at the forest and at the pasture.

A epidemiologia da nutrição dispõe de uma gama de metodologias para avaliar o estado nutricional. Entretanto, os métodos dietéticos são os únicos capazes de detectar a deficiência nutricional em seu estágio inicial, sendo por isso bastante utilizados em estudos epidemiológicos de associação entre exposições e eventos. Atualmente, o método dietético mais indicado para estudos epidemiológicos, principalmente aqueles envolvendo doenças crônico-degenerativas, tem sido o questionário semiquantitativo de freqüência alimentar (QSFA). Este instrumento, não diferente de outros, está sujeito à variabilidade e a erros de medida. Entretanto, estes podem ser identificados e tratados utilizando-se métodos como comparação de médias dietéticas, estudos de confiabilidade, de validação relativa e de calibração. Em estudo realizado em Bambuí-MG, o consumo de nutrientes foi avaliado por três diferentes métodos: QSFA e recordatórios 24 horas (R24) com e sem réplicas de alimentos, tendo suas médias comparadas e calibradas. As médias encontradas pelo QSFA foram consistentemente maiores do que as dos R24. No entanto, quando essas foram ajustadas pelo consumo calórico total não apresentaram diferenças importantes, exceto para fibras; zinco; vitaminas C; B6, e E; e colesterol. E as médias calibradas foram, em geral, menores do que as não calibradas, sendo estatisticamente significantes para ingestão de lipídeos; fibras; zinco; vitaminas C, E e A; ácidos graxos saturados, monoinsaturados e poliinsaturados; e colesterol.There are several approaches aiming to evaluate nutritional status available for epidemiological studies. Dietary methods are some of the most recommended because of their ability to detect nutritional deficiency in its initial stage. Currently, the Semiquantitative Food Frequency Questionnaire (SFFQ) has been chosen as the best dietary method, especially when dealing with chronic degenerative diseases. This tool, like many others, is subject to intrinsic variability and measurement errors. However, both phenomena can be identified and somehow treated through different methodologies such as comparison of dietary means, reliability studies, relative validity and calibration. In a study carried out in the town of Bambuí, nutrient intake measurements were obtained using SFFQ with photos and the 24-Hour Recall (R24) questionnaire with and without foodstuff replicas. Average nutrient intake obtained by the SFFQ was significantly higher compared to R24 questionnaires for all nutrients. However, when the averages were adjusted for total caloric intake, means were similar, except for fiber, zinc, vitamins C, B6 and E, and cholesterol consumption. The calibrated averages obtained by SFFQ were generally lower than those from the non-calibrated SFFQ and significant for lipids; fiber; zinc; vitamins C, E and A; saturated, monounsaturated and polyunsaturated fatty acids intake.

OBJECTIVE: To determine technical procedures and criteria used by Brazilian physicians for measuring blood pressure and diagnosing hypertension. METHODS: A questionnaire with 5 questions about practices and behaviors regarding blood pressure measurement and the diagnosis of hypertension was sent to 25,606 physicians in all Brazilian regions through a mailing list. The responses were compared with the recommendations of a specific consensus and descriptive analysis. RESULTS: Of the 3,621 (14.1%) responses obtained, 57% were from the southeastern region of Brazil. The following items were reported: use of an aneroid device by 67.8%; use of a mercury column device by 14.6%; 11.9% of the participants never calibrated the devices; 35.7% calibrated the devices at intervals < 1 year; 85.8% measured blood pressure in 100% of the medical visits; 86.9% measured blood pressure more than once and on more than one occasion. For hypertension diagnosis, 55.7% considered the patient's age, and only 1/3 relied on consensus statements. CONCLUSION: Despite the adequate frequency of both practices, it was far from that expected, and some contradictions between the diagnostic criterion for hypertension and the number of blood pressure measurements were found. The results suggest that, to include the great majority of the medical professionals, disclosure of consensus statements and techniques for blood pressure measurement should go beyond the boundaries of medical events and specialized journals.

INTRODUÇÃO: Os índices mais utilizados para medir a freqüência da cárie dentária em populações são o CPO-D, para dentes permanentes, e o ceo-d, para dentes temporários. A Organização Mundial da Saúde vem estabelecendo, desde os anos 60, padrões para os levantamentos de cárie dentária, a fim de melhorar a validade e a confiabilidade dos dados. Tem havido questionamentos, porém, quanto à validade e à confiabilidade de dados obtidos com essas diferentes padronizações da metodologia, quando são introduzidas mudanças nos critérios utilizados para definir o que é cárie dentária. OBJETIVO: Comparar os dados obtidos de uma mesma população de referência, empregando diferentes padronizações dos índices CPO-D e ceo-d, com a finalidade de verificar se essas diferenças nos critérios alteram significativamente as estimativas. METODOLOGIA: Foram utilizados dados secundários, obtidos em levantamentos epidemiológicos realizados no município de São Paulo, em 1996 e 1998. Analisaram-se as médias e a distribuição dos valores dos índices CPO-D e ceo-d, em escolares de 6 a 12 anos de idade, comparando-se estatisticamente médias e proporções. Admite-se que outros aspectos metodológicos, como os planos amostrais e os treinamentos de calibração, também poderiam alterar os resultados. RESULTADOS: Não se observou diferença estatisticamente significativa entre as médias. Houve diferenças significativas nas porcentagens de indivíduos livres de cárie na dentição permanente; o mesmo não aconteceu com os dentes decíduos. CONCLUSÃO: Os diferentes critérios empregados para definir cárie dentária não levaram à obtenção de médias e porcentagens estatisticamente diferentes nos três levantamentos.INTRODUCTION: The DMF-T index is the most widely used instrument to estimate prevalence of dental caries on permanent teeth in epidemiological surveys. Since the 60's, the World Health Organization has been recommending standards for oral health surveys to improve validity and reliability of epidemiological data. During this period, different criteria for diagnosis and coding the observations have been used. OBJECTIVE: To compare data from the same population using different standardizations for DMF-T and dmf-t indexes in order to verify if changing dental caries criteria redounds to different population estimates. MATERIAL AND METHOD: Data from three epidemiological surveys carried out in the City of São Paulo in 1996 and 1998 were analyzed. These surveys had different methodological aspects as sample design and calibration of examiners. DMF-T averages and value distribution related to schoolchildren from 6 to 12 years of age were analyzed comparing averages and proportions. RESULTS: No significant difference was observed between averages. There were no significant differences in percentages of caries- free individuals in relation to deciduous dentition, unlike permanent teeth. CONCLUSION: Different criteria used to define dental caries did not lead to different averages and percentages in these three surveys.

Os levantamentos epidemiológicos são importantes para o conhecimento da prevalência e tipologia das doenças bucais, podendo-se a partir dos dados coletados, planejar, executar e avaliar ações de saúde. É necessário, no entanto, que haja rigor metodológico que garanta reprodutibilidade, validade e confiabilidade, e que haja uniformidade de procedimentos para permitir comparações nacionais e internacionais. A iniciativa da Organização Mundial da Saúde (OMS) na assessoria à realização de levantamentos tem se mostrado extremamente útil, estimulando o estabelecimento de padrões de procedimentos que podem ser utilizados em todos os países. Em 1991 foi publicada a edição em português da terceira edição do "Oral Health Surveys - basic methods", de 1987, um manual que objetiva fornecer instruções para a realização de levantamentos epidemiológicos e tal publicação passou a servir de base a estudos realizados em diversos locais do Brasil e do mundo. O objetivo deste trabalho, é analisar criticamente a metodologia para Levantamento Epidemiológico em Saúde Bucal da OMS, na tentativa de contribuir para o aperfeiçoamento da mesma. De acordo com a presente análise, foram encontrados pontos relevantes para consideração, referentes à amostragem, à calibração dos examinadores e aos critérios para a avaliação de saúde bucal e necessidades de tratamento. Concluiu-se, em nível de recomendação, que, devido ao caráter dinâmico do conhecimento científico e, levando-se em consideração as diferenças regionais com relação ao padrão de desenvolvimento das doenças bucais, as propostas de padronização de levantamentos devem ser periodicamente revisadas. É provável, ainda, que outros pontos importantes não tenham sido detectados nesta análise, tornando-se premente ampliar esta discussão para toda a comunidade odontológica.Epidemiological surveys are important for obtaining information on the prevalence and etiology of mouth diseases, since the data collected permit health actions to be planned, performed, and assessed. Methodological uniformity is necessary, however, to maintain reproductibility, validity, and reliability, and to allow national and international comparisons. The initiative of the World Health Organization (WHO) as an advisor in ongoing surveys has been extremely useful, stimulating standardization in all countries. In 1991, a Portuguese version of the 1987 third edition of "Oral Health Surveys - basic methods", an instruction manual for performing epidemiological surveys, was published and became a reference for many parts of Brazil and the World. The present analysis found conflicting points in relation to the sample size, calibration of the examiners, and criteria for evaluating oral health and treatment needs. In conclusion, due to the dynamic characteristics of scientific knowledge and, considering the regional differences in relation to the development of oral diseases, we recommend that proposals for standardizing surveys be checked periodically. Other important issues may have not been detected in this analysis, urging a thorough discussion within the dentistry community as a whole.

The SEC and VPO behaviour of hydroxyl-terminated polybutadiene resins was investigated using toluene as solvent and polybutadiene and polystyrene as standards. The results show that molar mass obtained depend on the nature of the standards used in the calibration, specialy in SEC analysis.

A neutron probe calibration correction is proposed in order to reduce soil water content variability, assumed to be a consequence of improper calibrations relations. The time stability of spatially measured soil water content data is used to correct the intercepts of linear calibration relations. This procedure reduced the coefficients of variation of soil water content data from 4 to less than 2% in a Rhodic Kanhapludalf.É proposta uma correção para a calibração de sondas de nêutrons para reduzir a variabilidade de dados do conteúdo de água no solo, suposta como conseqüência de relações de calibração impróprias. A estabilidade temporal de dados espaciais de conteúdo de água no solo é usada para corrigir os coeficientes lineares de curvas de calibração. Esse procedimento reduziu coeficientes de variação de medidas de umidade do solo de 4 para valores menores que 2% em uma Terra Roxa Estruturada.

A utilização de sacos plásticos graduados para a medida da vazão de pulverizadores está ba stante di fundida entre técnicos e agricultores. 0 seu emprego é simples, consistindo, basicamente, em se coletar o líquido pulverizado por um bico durante o período equivalente ao deslocamento de 50 metros. O volume coletado é indicado numa escala graduada impr essa nos sacos calib rad ores e fornece diretament e a vazão em 1/ha. Firmas que comercializam os agro fármacos distribuem esses instrumentos aos agricultores, muitas vezes com propósitos puramente promocionais. Cinco sacos graduados de cada uma das 6 marcas diferentes foram aferidos. Agua a 20°C foi adicionada até as marcas de 100 1/ha, 250 1/ha e 400 1/ha. Esses volumes foram medidos em pro veta graduada e o volume real de pulverização foi calculado. Todos os saquinhos testados mostraram erros, em alguns bastante elevados, atingindo desvios de até 35,2%. Considerando esses resultados, é recomendada maior atenção na fabricação desses instrumentos. São sugeridas também algumas modificações da maneira de imprimir a escala e no conteúdo das instruções de uso.The utilization of graded poly then e bags for meas urement of spray throught put is current practice among technicians and farmers. It s us e is very simple, basically, the liquid sprayed from one nozzle is collected during a period equivalent to run 50 meters. The volume collected is indicated on a scale printed on the bags with gives the spray volume in 1/ ha directly. Free sample of these plastic calibrators are distributed for promotional purpose by the pesticides companies. Five bags of each of 6 different brands were checked. Water at 20°C was filled in to the level of 100 1/ha, 250 1/ha and 400 1/ha. These volumes were meas ured in a standardized measuring cylinder and the actual spray volume calculated. Positive and negative errors of measure ment were found in all graded polithe ne bags. The largest error was 35,2% higher than the indicated mark. Considering these results one can recommend more accuracy in manufacturing such a device. It is also suggested modifications in printing graded scale and operating instructions.

Abstract: Objective: To identify desirable characteristics, including different sample sizes and dental caries prevalences, in virtual samples that allow, at the same time, higher values of general agreement percentage (GPA) and Kappa coefficient (κ), under a low confidence interval (CI), in reproducibility studies. Method: A total of 384 statistical simulations of inter-examiner calibration, varying sample size (12, 15, 20, 60, 200 and 500 individuals), caries prevalence (30, 50, 60 and 90%) and percentages of positive (PA) and negative (NA) agreement (30, 50, 60 and 90%) were undertaken. GPA and κ were used to measure reproducibility and define deviation between them. Results: The sample of 60 individuals, under caries prevalence of 50%, PA and NA of 90%, presented a GPA and Kappa values of 90 and 80%, respectively, a relative small confidence interval (95%CI 0.65 - 0.95) and a GPA/Kappa deviation of 10.00. Conclusion: A virtual sample of 60 individuals, under caries prevalence of 50%, seems feasible to produce a satisfactory interexaminer agreement at epidemiological conditions. However, epidemiological studies to corroborate or refute this assertion are necessary.

This work reports the development of a certified reference material (CRM) of holmium(III) oxide Ho2O3 in acidic solution for the wavelength scale calibration of UV-Vis spectrophotometers. A 4.0% Ho2O3 solution was gravimetrically prepared in 10% perchloric acid and bottled in 5.0 mL glass ampoules. Homogeneity, stability and characterization were assessed according to ISO 17034 and ISO Guide 35. The material certification was undertaken by two laboratories by using UV-Vis spectrophotometry for characterization of the 14 peaks of minimum transmittance of Ho2O3, using a spectral bandwidth of 1.00 nm and a scanning speed of 30.0 nm min‒1. The material property values in wavelength (nm) were obtained for these 14 peaks, together with the expanded uncertainty (U) of 0.12 nm, for a coverage factor (k = 2.00) corresponding to a probability of approximately 95%, which took into account the standard uncertainties obtained in each study performed for the certification of the produced reference material.

In this work we measured light intensity as a function of time during a total solar eclipse using a solar cell. The measured intensity was corrected for the detector response and compared with a mathematical expression that represents the uncovered apparent area of the solar disk as a function of time. By no means, this corrected intensity is linearly related to the uncovered area, this being due to effects such as the solar corona luminosity, the limb darkening and light scattered in the atmosphere. Estimates of the fraction of light that causes this deviation from linearity are given.

ABSTRACT Hydrological models are tools which describe processes and allow predicting the results of making management decisions, and are an important water resource management tool, especially for small-sized watersheds. This work had as an objective to test different calibration strategies and apply the SWAT model for hydrological simulation of the Mortes River Basin, MG. We evaluated 6 fluviometric stations, with drainage area between 272 and 6070 km² for purposes of water resource management. The evaluation of the model performance was conducted by using Nash-Sutcliffe coefficients (CNS) and percent bias (PBIAS). The results obtained from the statistic indices applied in the analysis of the model performance qualified the SWAT hydrological model as adequate for streamflow simulation in the Mortes River Basin. The adopted strategies attest to the applicability of the model as a management tool for water resources planning for other small-sized watersheds without data, in order to plan for rational water use.