Verônica Yumi Kataoka

Statistics School Curricula in Brazil

In Brazilian basic education, National Curricular Parameters recommend the inclusion of probability and statistics as part of mathematics. Despite the innovative character and methodological guidelines focused on the formation of a scientific spirit and on civic preparation, teaching probability and statistics faces difficulties because of lack of training for teachers, didactic materials, and availability of software, among others. Therefore, statistics educators in Brazil have hard but promising work ahead.

Eletrical conductivity test to evaluate physiological quality of castor bean seeds

The increasing demand for castor bean seeds in Brazil has promoted more interest in the development of tests to assess seed lots with superior quality. To investigate the possibility of using the electrical conductivity test for evaluation of the physiological quality of castor bean seed, ten seed lots from the cultivars AL Guarany 2002 and IAC 80 were used. The seeds were submitted to the bulk and individual conductivity test in four imbibition periods (6, 12, 18 and 24 hours). The lots were characterized by the germination test, first count, seedling emergency, initial emergency, emergence speed index and tetrazolium test. The moisture content of the seeds, the imbibition curve and seed health were also determined. The bulk conductivity test was carried out by using plastic cups with 25 seeds each in 75 ml deionized water, incubated in a BOD at a constant temperature of 25°C. The individual conductivity was determined by an SAD-9000S automatic seed analyzer. In contrast to the determination of seed physiological quality using the individual conductivity test, the bulk conductivity test was efficient in the detection of differences in castor seed lot quality and the period of 6 hours was the imbibition time indicated for the test.

DETERIORATION OF SUNFLOWER SEEDS DURING STORAGE

The speed on deterioration of oil-seeds depends on conditions of the storage environment and on particularities of the species, which include the seed chemical composition. Within this study, the changes on quality of sunflower seeds, stored in different packaging types and environmental conditions, were investigated. The packaging used were multiwall Kraft paper and plastic packaging (with and without vacuum), under cold chamber and conventional storage conditions. Seed quality was evaluated by tests of: germination and accelerated aging; besides alterations on oil content, fatty acids profile, and isoenzymatic systems. The storage under cold chamber conditions was more efficient in maintaining physiological quality of sunflower seeds; and under such environment, the Kraft paper packaging was the most adequate. Under conventional storage facility, however, the plastic packaging, sealed with vacuum, has provided better maintenance of physiological quality. Changes in the sunflower seed quality were detected by the enzymatic systems: alcohol dehydrogenase and superoxide dismutase. The oil content in seeds decreases over time, regardless of storage condition. The linoleic and oleic acids constituted 80% of the total amount of fatty acids scanned. There have been no significant differences on the fatty acid profiles of the sunflower oil under the different storage conditions studied.

Oil radish seeds processing

Seed Seed processing is a subsequent step for production which aims to improve lot quality, making seeds appropriate for commercialization. For species whose seeds have differences in density due to non-uniform maturation or are very susceptible to mechanical damage, such as the fodder radish, the understanding of the processing effects on the physiological potential of the lots is fundamental. Two lots of the cultivar CATI Al-1000, 2006 harvest, were submitted to processing by air screen separator and gravity table (high, intermediate high, intermediate low and low discharge) and their physiological and physical aspects evaluated. The following were determined: moisture content, purity, weight per thousand seeds, germination, first germination count, germination speed index, initial stand, emergence, emergence speed index, dry matter of seedling aerial part and health quality. It was concluded that to satisfy the minimum standards of purity and germination for commercialization of certified fodder radish seeds, lots must be processed by air screen separator and gravity table. The air screens machine and air and gravity table are efficient for separating the fodder radish seed lots into fractions with different physical and physiological quality. The lower density fodder radish seeds have lower physiological quality.

Teste de condutividade elétrica na avaliação de sementes de girassol armazenadas sob diferentes temperaturas

Deterioration is a problem in seed storage, particularly for oleaginous seeds. Research has shown that conductivity test results may be influenced by seed storage temperatures suggesting that seed deterioration, especially at low temperatures, does not seem to be directly related to the loss of cell membrane integrity. To investigate the effect of different storage temperatures on electrical conductivity in sunflower seeds (Helianthus annuus L.), seeds of two sunflower hybrids, Helio 250 and Helio 251, were packaged in layered Kraft paper and stored at the following temperatures: 10 °C, 25 °C and 25/10 °C. Seed physiological quality was evaluated every three months during a 12 months storage period from germination, seedling emergence, accelerated aging and electrical conductivity tests. Seed water content was also determined. The electrical conductivity test was not efficient in detecting deterioration in sunflower seed stored at low temperatures.

Validation of methodologies for germination test in oil radish seed (Raphanus sativus L. var. oleiferus)

For several vegetable species, there is no procedure in the Rules for Seed Testing used in Brazil for tests such as germination, due to lack of standardization and methodological validation. Among these species is oil radish, a promising crop for bio-diesel production, whose germination is assessed by the methodology recommended for Raphanus sativus, although it has varietal specificity (var. oleiferus) with plant and seed characteristics that differ from other varieties of the species. To ensure standardization of methodologies for the international seed trade, The International Seed Testing Association (ISTA), establishes criteria for methodology validation, whose description should be clear and complete with procedures that should be accurate, robust and precise (reproducibility and repeatability). In this the study aims was to evaluate the validation process of two methodologies for the germination test in oil radish seeds, using the ISTA standard procedure, as well as complementary techniques, for statistical analyses. Germination tests were done in eight laboratories with five lots, using sand and paper substrates with alternating temperatures of 20-30 oC. Statistical techniques were used to verify the homogeneity of lots (H test), identify the presence of discrepant values (Hampel method) and outliers in variances (Levenes test for average); assess the effects of laboratories and lots (analysis of Variance); verify repeatability, reproducibility, accuracy and robustness (critical limits of repeatability, reproducibility, Mandels h and k statistics); compare different germination methods (F tests); and reevaluate the quality level of lots (Discrimination Analysis). Both in statistical and phytotechnical aspects, the methodologies for the germination test in oil radish seeds with sand and paper substrates and alternating temperatures of 20-30 oC can be consider validated, as they demonstrated accuracy, robustness, repeatability and reproducibility.

Statistical Training of Pre-service Teachers with Application in School Practice

This chapter discusses the way that actions developed under a programme from the Brazilian government can contribute to the learning of teaching, by considering four pre-service mathematics teachers (undergraduate students), from the university in Sao Paulo, who participated in a training activity using Didactical Sequences (DS) of Statistics, and then applied these to students in their sixth to ninth years of schooling. It is considered that programme has provided training times to pre-service teachers, who learn the necessary concepts for teaching, as well as how to prepare and execute activities in the classroom with the guidance and under the supervision of professors and teachers. Therefore, those activities provide security for pre-service teachers in their teacher training.

Exploring Dot Plot in the Perspective of Embodied Cognition

The effective inclusion of Probability and Statistics teaching in Brazilian schools faces great challenges, including teachers’ training and a lack of didactic materials and software. Conceptual errors are common, even with teachers and textbooks, and many important graphs are not explored. A group of Statistics educators developed a free virtual learning environment with didactic sequences (DS) to help Probability and Statistics teachers at school. The objective of this chapter was to present theoretical aspects of human and paper dot plot exploration in the perspective of embodied cognition, and then explore students’ experiences with human and paper dot plots. It was observed that the human dot plot as a graphic representation seemed to then become less abstract.

Redução do tempo de avaliação do teste de germinação de sementes de girassol

Establishing ideal conditions and speed in carrying out the germination test for sunflower seeds is of utmost importance in quality control programs of companies dedicated to the production of high technology seeds. In this regard, the aim of this study was to verify the possibility of reducing the evaluation time of the germination test of sunflower seeds in different substrates and temperatures. Six seed lots of the cultivar Helio 251 and six lots of the cultivar Helio 253 were used. As well as germination, determinations were made of first count germination and seed health. The seeds were kept in a germination chamber at 25 oC, 30 oC, and 20-30 oC for the paper substrate, and 25 oC and 30 oC for the sand substrate. To verify the possibility of reducing the evaluation time of the germination test, the number of normal seedlings were counted daily, up to the tenth day after sowing. It was concluded that it is possible to conclude the germination test on the seventh day after sowing in sand at the temperature of 25 °C.