Physical quality of an Oxisol cultivated with maize submited to cover crops in the pre-cropping period

The intensive use of land alters the distribution of the pore size which imparts consequences on the soil physical quality. The Least Limiting Water Range (LLWR) allows for the visualization of the effects of management systems upon either the improvement or the degradation of the soil physical quality. The objective of this study was to evaluate the physical quality of a Red Latosol (Oxisol) submited to cover crops in the period prior to the maize crop in a no-tillage and conventional tillage system, using porosity, soil bulk density and the LLWR as attributes. The treatments were: conventional tillage (CT) and a no-tillage system with the following cover crops: sunn hemp (Crotalaria juncea L.) (NS), pearl millet (Pennisetum americanum (L.) Leeke) (NP) and lablab (Dolichos lablab L.) (NL). The experimental design was randomized blocks in subdivided plots with six replications, with the plots being constituted by the treatments and the subplots by the layers analyzed. The no-tillage systems showed higher total porosity and soil organic matter at the 0-0.5 m layer for the CT. The CT did not differ from the NL or NS in relation to macroporosity. The NP showed the greater porosity, while CT and NS presented lower soil bulk density. No <= 10 % airing porosity was found for the treatments evaluated, and value for water content where soil aeration is critical (theta(PA)) was found above estimated water content at field capacity (theta(FC)) for all densities. Critical soil bulk density was of 1.36 and 1.43 Mg m(-3) for NP and CT, respectively. The LLWR in the no-tillage systems was limited in the upper part by the theta(FC), and in the bottom part, by the water content from which soil resistance to penetration is limiting (theta(PR)). By means of LLWR it was observed that the soil presented good physical quality.

Produtividade do milho relacionada com a resistência mecânica à penetração do solo sob preparo convencional

A resistência mecânica do solo à penetração exerce grande influência sobre o desenvolvimento vegetal, uma vez que o crescimento das raízes e a produtividade das culturas variam de forma inversamente proporcional ao seu valor. O objetivo do trabalho foi estudar a variabilidade espacial e a correlação entre a produtividade do milho (PG) e a resistência mecânica do solo à penetração (RP) de um Latossolo Vermelho sob preparo convencional, em área pertencente à Fazenda Experimental de Ensino e Pesquisa da Faculdade de Engenharia - FE/UNESP - Câmpus de Ilha Solteira. Foram definidos 133 pontos de amostragem no campo, segundo malha com espaçamento regular de 10,0 m, nos quais foram medidas a RP, a umidade gravimétrica (UG), nas camadas de 0-0,10; 0,10-0,20; 0,20-0,30 e 0,30-0,40 m, e a PG. O modelo exponencial mostrou-se adequado para descrever todos os semivariogramas experimentais construídos. A RP e a UG apresentaram moderada dependência espacial, com alcance variando entre 20,2 e 63,0 m. A PG apresentou forte dependência espacial com alcance de 15,3 m. A RP não apresentou correlação espacial com a PG. Valores de RP variando entre 0,9 e 2,0 MPa não restringiram a PG.

Compactação do solo e intervalo hídrico ótimo no crescimento e na produtividade da cultura do milho

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Soil resistance to penetration and least limiting water range for soybean yield in a haplustox from Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Postharvest quality of twelve onion cultivars grown in the Southeast of Brazil

Onions (Allium cepa L.) are grown in different parts of the Brazilian territory and are considered the third most important vegetable crop cultivated in the country, only behind potatoes and tomatoes. The present work was carried out aiming to evaluate the postharvest quality of twelve different onion cultivars grown in the Southeast of Brazil. Onions of the cultivars; 'Adocicada', 'Branca', 'Picante' and 'Roxa' were harvested in commercial fields and the cultivars 'Princesa', 'Serrana', 'Bulbo duplo', 'Granex 33', 'XP 6803', 'XP 8418', 'RP 6010' and 'Superex' were obtained in experimental fields. After harvest, bulbs were taken to the postharvest laboratory and evaluated for total soluble solids, titratable acidity, and pungency (aliinase activity). For total soluble solids 'Superex' had the lowest sugar content (5.4 degrees Brix) whereas the cultivar named 'Picante' showed the highest Brix (11.0 degrees Brix) among the studied materials. For titratable acidity, it was verified that 'Serrana' had the lowest acid content (0.094 g piruvic acid.100 g(-1) FW) whereas 'Branca' showed the highest content of organic acids. When pungency was evaluated it was verified that aliinase activity varied from 1.37 pg piruvic acid.100 g(-1) FW for 'Adocicada' to 12.18 mu g piruvic acid.100 g(-1) FW for 'Roxa', which was considered to have hot pungency (high alliinase activity and low TSS/TA), whereas 'Bulbo duplo' was evaluated as pungent (high alliinase activity and TSS/TA). The combination of the studied characteristics indicated that an onion with high pungency must have high aliinase activity and titratable acidity, whereas sweet onions shall have high soluble solids contents and low aliinase activity. Based on this information, 'Branca' bulbs were considered acids (weak pungency and high acidity), whereas 'Adocicada', 'Princesa', and 'Serrana' bulbs are sweet, due to low alliinase activity and titratable acidity. 'Superex', 'XP 6803', 'Granex 33' and 'Picante' had a moderately pungent flavor (alliinase activity intermediate and low TSS/TA), but 'XP 8418' and 'RP 6010' flavor was evaluated as lightly pungent (low alliinase activity TSS/TA).

Eucalyptus ESTs involved in mechanisms against plant pathogens and environmental stresses

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Atividade de quitinases e peroxidases em folhas de eucalipto em diferentes estágios de desenvolvimento após tratamento com acibenzolar-S-metil (ASM) e inoculação com Puccinia psidii

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeito de indutores bióticos e abióticos na atividade de quitinase e peroxidase e no controle da ferrugem causada por Puccinia psidii em eucalipto

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A estratégia didática de resolução de problemas na formação de professores de química

In this work it is presented a research developed in the initial training of teachers of the chemistry graduation course at the Universidade Federal do Rio Grande do Norte (UFRN). The intervention was realized in two classes in the context of a discipline in the curricular structure with nineteen undergraduate students of chemistry. The study utilizes characteristics of the qualitative approach and uses observation, questionnaires, interviews and examination papers. The experiment involved a sequence of activities fundamented on the Problem Solving (PS) teaching strategy to approach chemical concepts. The proposal was planned and organized according to the theoretical presupposition of the work developed by the authors of the Science Education in PS, of teaching experience and from the initial hypotheses of the research. The goal was that the future teachers could experience the strategy and advance to the new meanings. The themes addressed in the activities were the difference between exercises and problems, exercises turning into problems, the steps of problem solving and some implications of the teaching strategy for the work of the teacher. The results showed evidence that through a process of collective reflection, and from the difficulties experienced in the strategy practice, the undergraduates are introduced to new perspectives of reflection and action of teaching practice, and understanding some benefits of innovative proposals for the teaching of chemistry. It also showed that, although this theme is approached, in some moments of the graduation, the future teachers don‟t know when or how to realize activities in this perspective. From the aspects that rose in research we highlighted the difficulties in the problem solving steps, the use of the strategy in school and the knowledge and skills of the teacher for planning activities in Problem Solving

Obtenção de oligossacarídeos N-ligados às glicoproteínas dos líquens Sticta tomentosa e Sticta damaecornis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Determination of amfepramone hydrochloride, fenproporex, and diazepam in so-called natural capsules used in the treatment of obesity

A simple and rapid method was developed for the determination of amfepramone hydrochloride, fenprorex, and diazepam in capsules using high performance liquid chromatography (HPLC) with UV detection. This procedure provided conditions for the separation of the active ingredient from the complex matrices of the dosage forms by extraction in methanol. Isocratic reversed phase chromatography was performed using acetonitrile, methanol, and aqueous 0,1% ammonium carbonate (50:10:40) as a mobile phase, LiChrospher 100 RP 18 column (125 x 5 mm id, 5 mu m), a column temperature of 25 +/- 1 degrees C and detection at 230 nm.The calibration curves were linear over a wide concentration range (20-2000 mu g.mL(-1) to amfepramone hydrochloride, 8-800 mu g.mL(-1) to fenproporex, and 4-200 mu g.mL(-1) to diazepam) and good analytical recovery (87.1 to 107.8%) was obtained. The method is accurate and precise, as well as having advantages such as simplicity and short duration of analysis. Twenty samples of pharmaceutical preparations labelled as natural products were analysed. Anorectics and diazepam, were detected in 40% of the samples.

Application of an HPLC method for analysis of propolis extract

Propolis obtained from honeybee hives has been widely used in medicine, cosmetics, and industry due to its versatile biological activities (antioxidant, antimicrobial, fungicidal, antiviral, antiulcer, immunostimulating, and cytostatic). These activities are mainly attributed to the presence of flavonoids in propolis, which points out the interest in quantifying these constituents in propolis preparations, as well as validation of analytical methodologies. High-performance liquid chromatography (HPLC) methods have been reported to quantify isolated flavonoids or these compounds in complex biological matrices, such as herbal raw materials and extractive preparations. An efficient, precise, and reliable method was developed for quantification of propolis extractive solution using HPLC with UV detection. The chromatograms were obtained from various gradient elution systems (GES) tested in order to establish the ideal conditions for the analysis of propolis extractive solution, using methanol and water: acetonitrile (97.5 : 2.5, v/v) as mobile phase. Gradient reversed phase chromatography was performed using a stainless steel column (250 x 4.6 mm i.d., 5 mum) filled with Chromsep RP 18 (Varian), column temperature at 30.0 +/- 0.1degreesC and detection at 310 nm. The main validation parameters of the method were also determined. The method showed linearity for chrysin in the range 0.24-2.4 mug mL(-1) with good correlation coefficients (0.9975). Precision and accuracy were determined. The obtained results demonstrate the efficiency of the proposed method. The analytical procedure is reliable and offers advantages in terms of speed and cost of reagents.

Determination of oxamniquine in capsules by HPLC

A sensitive, accurate, reliable and easy method was developed for the quantification of oxamniquine in capsules using high-performance liquid chromatography (HPLC) with UV detection. This technique provided conditions for the separation of the active ingredient from the dosage form by extraction in methanol. Isocratic reversed phase chromatography was performed using methanol, water, and triethanolamine (60:40:0.099, v/v/w) (System C) or methanol, acetonitrile, water and formic acid (40:30:30:0.083, v/v/w) (System D) as mobile phase, a stainless steel column (125 x 4 mm i.d., 5 mum) filled with LiChrospher 100 RP-18 (Merck), column temperature of 28 +/- 2 degreesC and detection at 260 nm. The calibration curves were linear over a wide concentration range (1.0-20.0 mug ml(-1) of oxamniquine) to the Systems C and D with good correlation factor (0.9990 and 0.9982, respectively). The average content obtained were 100.1 +/- 1.5% (System C) and 102.4 +/- 0.8% (System D). The presence of lactose, starch, magnesium stearate and sodium laurylsulphate did not interfere in the results of the analysis. The above findings showed the proposed method to be both simple and added advantage of allowing for fast analysis. (C) 2001 Elsevier B.V. B.V. All rights reserved.

Development of a Validated Stability-Indicating LC Assay and Stress Degradation Studies of Linezolid in Tablets

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Structural characterization and in vivo evaluation of retinyl palmitate in non-ionic lamellar liquid crystalline system

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)