Biochemical traits useful for the determination of genetic variation in a natural population of Myracrodruon urundeuva

The objectives of this work were to analyze seeds from 20 trees of aroeira (Myracrodruon urundeuva Fr. All.) of a natural population located in the region of Selvíria, State of Mato Grosso do Sul, Brazil, in order to evaluate their protein, lipid and carbohydrate contents, and to estimate their genetic variation. A completely randomized experimental design consisting of 20 treatments (families) was set up, with two replications. Four types of proteins were detected: albumin (35.0 to 107.3 mg/g seed), globulin (3.4 to 9.3 mg/g), prolamin (60.0 to 135.2 mg/g) and glutelin (118.0 to 286.0 mg/g). The lipid content varied between 200 and 334 mg/g seed. The total sugars also varied (26.5 to 46.3 mg/g seed), with a predominance of polyols (arabinitol, mannitol, glucitol and xylitol). The main monosaccharides detected were glucose and arabinose. Total hydrolysis of the sugars indicated the presence of neutral arabinan and xylan oligosaccharides. The starch content varied from 0.35 to 1.58 mg/g seed. These biochemical traits showed considerable genetic variability, indicating that only the collection of seeds from many different trees can provide a representative sample of the population for conservation and genetic improvement.

Soybean crop area estimation by Modis/Evi data

The objective of this work was to develop a procedure to estimate soybean crop areas in Rio Grande do Sul state, Brazil. Estimations were made based on the temporal profiles of the enhanced vegetation index (Evi) calculated from moderate resolution imaging spectroradiometer (Modis) images. The methodology developed for soybean classification was named Modis crop detection algorithm (MCDA). The MCDA provides soybean area estimates in December (first forecast), using images from the sowing period, and March (second forecast), using images from the sowing and maximum crop development periods. The results obtained by the MCDA were compared with the official estimates on soybean area of the Instituto Brasileiro de Geografia e Estatística. The coefficients of determination ranged from 0.91 to 0.95, indicating good agreement between the estimates. For the 2000/2001 crop year, the MCDA soybean crop map was evaluated using a soybean crop map derived from Landsat images, and the overall map accuracy was approximately 82%, with similar commission and omission errors. The MCDA was able to estimate soybean crop areas in Rio Grande do Sul State and to generate an annual thematic map with the geographic position of the soybean fields. The soybean crop area estimates by the MCDA are in good agreement with the official agricultural statistics.

CO2-response function of radiation use efficiency in rice for climate change scenarios

The objective of this work was to evaluate a generalized response function to the atmospheric CO2 concentration [f(CO2)] by the radiation use efficiency (RUE) in rice. Experimental data on RUE at different CO2 concentrations were collected from rice trials performed in several locations around the world. RUE data were then normalized, so that all RUE at current CO2 concentration were equal to 1. The response function was obtained by fitting normalized RUE versus CO2 concentration to a Morgan-Mercer-Flodin (MMF) function, and by using Marquardt's method to estimate the model coefficients. Goodness of fit was measured by the standard deviation of the estimated coefficients, the coefficient of determination (R²), and the root mean square error (RMSE). The f(CO2) describes a nonlinear sigmoidal response of RUE in rice, in function of the atmospheric CO2 concentration, which has an ecophysiological background, and, therefore, renders a robust function that can be easily coupled to rice simulation models, besides covering the range of CO2 emissions for the next generation of climate scenarios for the 21st century.

Rice yield estimation based on weather conditions and on technological level of production systems in Brazil

The objective of this work was to evaluate an estimation system for rice yield in Brazil, based on simple agrometeorological models and on the technological level of production systems. This estimation system incorporates the conceptual basis proposed by Doorenbos & Kassam for potential and attainable yields with empirical adjusts for maximum yield and crop sensitivity to water deficit, considering five categories of rice yield. Rice yield was estimated from 2000/2001 to 2007/2008, and compared to IBGE yield data. Regression analyses between model estimates and data from IBGE surveys resulted in significant coefficients of determination, with less dispersion in the South than in the North and Northeast regions of the country. Index of model efficiency (E1') ranged from 0.01 in the lower yield classes to 0.45 in higher ones, and mean absolute error ranged from 58 to 250 kg ha‑1, respectively.

Development of a diagrammatic scale for the evaluation of postharvest physiological deterioration in cassava roots

Abstract:The objective of this work was to develop a scale to assess the severity of postharvest physiological deterioration (PPD) of cassava roots, and to validate this scale for accuracy and reproducibility estimates. A diagrammatic scale (0 to 100%) for the damaged roots was analyzed according to precision, accuracy, and reproducibility. Seven evaluators (four with experience and three without it) quantified the PPD severity, with or without the scale, considering 150 roots with different levels of PPD. Without and with the use of the scale, respectively, the inexperienced evaluators obtained coefficients of determination (R2) from 0.76 to 0.86 and 0.87 to 0.92, and the experienced evaluators obtained R2 from 0.90 to 0.96 and 0.96 to 0.97. The values of the intercept (a) obtained by both the experienced and inexperienced evaluators who did not use the scale were all significant, while after using the scale, only two evaluators got values that were not significantly different from one. Evaluation reproducibility between the evaluators ranged from 0.61 to 0.91 for the inexperienced ones and from 0.83 to 0.95 for the experienced ones. The proposed diagrammatic scale was considered appropriate to estimate the severity of PPD in cassava roots, and can be used to identify sources of tolerance to postharvest deterioration.

RAPD markers utilization and other parameters in the determination of mango hybrids genitors

Actually mango (Mangifera indica, L.) is considered one of the largest Brazilian fruitbusiness for the export market. Cultivar selection having high fruit quality is a fundamental step to obtain excellent results in this business. A mango breeding program based on intervarietal hybridization may produce new improved cultivars for mango growers. Mango hybrids have been obtained by controlled or open crosses. In the last one, it is important to identify the male parent because it is useful for the genetic cultivar history, thus it is important for planning further improvements. This work presents a parentage test using among others parameters RAPD (Random amplified Polymorphic DNA) markers to estimate the male parent of the selected hybrids in an open cross plot by using five mango cultivars densely planted in a latin square design.

Determination of thermal diffusivity in papaya pulp as a function of maturation stage

In order to determine the penetration of the thermal wave in the papaya fruit pulp (Carica papaya L.), cv. Golden, thermal diffusivity of the pulp was obtained measuring temperature at four different depths. Measurements were carried out initially with the fruit on the first stage of maturity. The changes of the thermal diffusivity were expressed as a function of ripening. A temporal decrease of the thermal diffusivity was observed. Chemical (pH, soluble solids and total titratable acidity) and physical (pulp firmness) properties were measured as well and the results were compared to the thermal diffusivity change.

Soil nutrient availability and its impact on fruit quality of Tahiti acid lime

The Tahiti acid lime in Brazil is mostly grown in the São Paulo State. The value of this crop production ranks among the ten most important fruits in the country. The Brazilian exports of Tahiti limes have increased in the last years with a corresponding increased demand for superior quality of fresh fruits, which is affected by mineral nutrients. Therefore, this study evaluated nutrient soil availability and its influence on nutritional status of trees based on the determination of leaf and fruit nutrient concentrations, fruit characteristics, and post harvest quality. Eleven commercial groves with trees older than 4-yr and differently managed were studied. Plots with six trees in each grove were sampled for soil (0-20 cm depth layer), leaf and fruit analyses with three replicates. Correlation coefficients were pair wised established for all variables. The results showed that N leaf concentration was well correlated with green color of fruit peel as measured by a color index (r = -0.71**), and which was optimum with Leaf-N around 22 g kg-1. Leaf-Ca was inversely correlated with fruit water loss after 14-day interval from harvest (r = -0.54*) demonstrating that Ca plays an important role in Tahiti fruit shelf-life. Data also suggested that increased fruit K concentration correlated with increased fruit water losses during storage (r >0.58*).

X-ray fluorescence determination of adsorbed copper on activated charcoal after glycerin complexation

X-This work shows an alternative method to copper determination by X-Ray Fluorescence (XRF). Since copper concentration in natural waters is not enough to reach XRF detection limit, a liquid-solid preconcentration procedure was proposed. Glycerin was used to complex the metal increasing its adsorption on activated charcoal. The solid phase was used to XRF determination. Several parameters were evaluated, such as, the complexation pH, the charcoal adsorption limit and the glycerin concentration. The interferences are lead and bismuth and the sensitivities decreased in the order Cu2+, Bi3+ and Pb2+. The advantages of the method are its simplicity, low cost and low spectral interference.

Spectrophotometric determination of cefaclor in pharmaceutical preparations

A simple spectrophotometric method is proposed for the determination of cefaclor. The method involves alkaline hydrolysis of the drug in ammonia buffer solution at pH 10 to yield diketopiperazine-2,5-dione derivative and subsequent measurement at 340 nm. Beer's law is obeyed in the concentration range 1.8 - 55 mg/mL. The proposed method was successfully applied to the determination of cefaclor in pharmaceutical formulations.

The determination of the stoichiometry of the mixed complex of vanadium with hydrogen peroxide and with 4-(2-Pyridilazo) Resorcinol

The present study reports details of the stoichiometric characterization of the mixed complex system, V(H2O2)PAR, formed when vanadium adequately reacts with hydrogen peroxide and with 4-(2-Pyridilazo)Resorcinol. Also the presence of polynuclear species was investigated in order to elucidate about unambiguous assignment of the molar absorptivity, stability constant and composition of the complex. Two mathematical treatments methods of the experimental results were employed. From the results it can be concluded that this system corresponds to a mononuclear complex with 1:1:1 stoichiometry.

Reação de geração de oxigênio em eletrodos de Mn2O3 suportados em aço inoxidável

A study of the kinetics of oxygen evolution in alkaline conditions from ceramic films of Mn2O3 supported on stainless steel was carried out. This study has been done through the determination of transfer coefficients, Tafel slopes and exchange currents using potentiodynamic and quasi-potentiostatic measurements. The activation energy was determined as a function of the overpotential and, additionally, the electrode active surface was estimated. The results are consistent with data already published for other electrodes, implying that the methods used in this work were reliable and precise.

Determination of the HMX and RDX content in synthesized energetic material by HPLC, FT-MIR, and FT-NIR spectroscopies

A new method has been developed for determining the content of mixtures of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), the HMX/RDX ratio, in explosive compositions by Fourier transform infrared spectroscopy (FT-IR), in the regions MIR (mid infrared) and NIR (near infrared) with reference values obtained by chromatographic analysis (HPLC). Plots of relative MIR (A917 / A783) or NIR absorbance values (A4412 / A4317) versus HMX/RDX ratio determined by HPLC analysis revealed good linear relationships.

Validation and statistical analysis of two high performance liquid chromatography methods for the determination of indinavir sulfate raw material and capsules

Two high performance liquid chromatography (HPLC) methods for the quantitative determination of indinavir sulfate were tested, validated and statistically compared. Assays were carried out using as mobile phases mixtures of dibutylammonium phosphate buffer pH 6.5 and acetonitrile (55:45) at 1 mL/min or citrate buffer pH 5 and acetonitrile (60:40) at 1 mL/min, an octylsilane column (RP-8) and a UV spectrophotometric detector at 260 nm. Both methods showed good sensitivity, linearity, precision and accuracy. The statistical analysis using the t-student test for the determination of indinavir sulfate raw material and capsules indicated no statistically significant difference between the two methods.

Development and validation of an alternative titration method for the determination of sulfate ion in indinavir sulfate

A simple and rapid precipitation titration method was developed and validated to determine sulfate ion content in indinavir sulfate raw material. 0.1 mol L-1 lead nitrate volumetric solution was used as titrant employing potentiometric endpoint determination using a lead-specific electrode. The United States Pharmacopoeia Forum indicates a potentiometric method for sulfate ion quantitation using 0.1 mol L-1 lead perchlorate as titrant. Both methods were validated concerning linearity, precision and accuracy, yielding good results. The sulfate ion content found by the two validated methods was compared by the statistical t-student test, indicating that there was no statistically significant difference between the methods.