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Search Results: 1 - 10 of 13728 matches for " Juliano Garcia;Coimbra "
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Uso ou abuso em testes de compara??es de média: conhecimento científico ou empírico?
Bertoldo, Juliano Garcia;Coimbra, Jefferson Luís Meirelles;Guidolin, Altamir Frederico;Miqueloto, Aquidauana;Toaldo, Diego;
Ciência Rural , 2008, DOI: 10.1590/S0103-84782008000400039
Abstract: the objective of this research was to verify which are the main mistakes and the successes in the application of mean comparison tests in scientific studies, demonstrating viable alternatives in the sense of increasing the impartiality of the results obtained by researchers. one of the researcher's largest challenges is the interpretation of the obtained results in a trustworthy way. in spite of the concern of most researchers with the data analysis, many times certain disregard is observed in the interpretation of the results. thus, the incorrect application of statistical tests leads the researchers to publish information not completely reliable. one hundred and forty-eight papers dealing with one or more than one factor were evaluated. all of them are related to the crop production major area, published from 2002 to 2006, in the 'ciência rural', a brazilian scientific journal. most of the studies (72%) were classified as incorrect due to the abuse of means comparison tests. in addition, only 4% and 24% were classified respectively as partially correct and correct.
Induction of genetic variability in oat
Jefferson Luis Meirelles Coimbra,Daniel Schwantes,Juliano Garcia Bertoldo,Mauricio Marini Kopp
Crop Breeding and Applied Biotechnology , 2007,
Abstract: Genetic variability in plants can be maximized through techniques of induction to make selection of genotypeswith improved adaptation to cultivation conditions possible. For oat, these techniques are important for a sustainabledevelopment through plant breeding programs in southern Brazil. The effects of mutagens (one physical: 60Co gamma raysand two chemical agents: ethyl - methanesulfonate and methyl-methanesulfonate) were compared in the segregating M2 andM3 generations derived from artificial hybridization and induced mutation to compare mechanisms of widening the geneticvariability of oat. The methodologies increased the genetic variability in the trait vegetative cycle effectively, by either increasingor reducing the number of days from emergence to full heading; both can be applied in oat breeding programs.
Root distribution in common bean populations used in breeding programs
Fabiani da Rocha,Marlon Mathias Dacal Coan,Jefferson Luís Meirelles Coimbra,Juliano Garcia Bertoldo
Crop Breeding and Applied Biotechnology , 2010,
Abstract: This study aimed to assess the root distribution of mutant common bean populations along the profile and toselect bean genotypes with higher metric values for the trait root distribution, with a view to their inclusion in a bean breedingprogram. In this field study the genotypes IPR Uirapuru, IPR Chopim, Pérola and IAPAR 81 were evaluated and three doses(0, 100 and 200 Gy) of mutagen gamma rays (Co60), nested in the depths of the soil profile. A completely randomized designwas used with two replications. The trait root distribution was measured in the presence (1) and absence (0) of roots. Theexperiment was arranged in a mixed factorial design where the factors genotypes and doses were crossed and depth wasnested within the levels of these factors, and the regressions showed significant differences of the genotypes. Analysis ofvariance revealed an interaction of genotype x dose, nested in the factor depth of the soil profile, and the regressions showedsignificant differences among the genotypes. The most promising segregating populations were those derived from thecultivars IPR Uirapuru and Pérola, since with increasing mutagen doses their root number increased significantly.
Stratification of the state of Santa Catarina in macro-environments for bean cultivation
Juliano Garcia Bertoldo,Jefferson Luís Meirelles Coimbra,Rubens Onofre Nodari,Altamir Frederico Guidolin
Crop Breeding and Applied Biotechnology , 2009,
Abstract: The purpose of this study was to suggest a division of the State of Santa Catarina in macro-environments forexperimentation and bean production. Data of the traits grain yield and plant cycle were evaluated in 10 common beangenotypes grown in nine environments. The data were submitted to the Student-Newman Keuls test, to detect differencesbetween environments, and the Best Linear Unbiased Prediction, to predict the environmental values. The results showed: (a)differences between the regions of Santa Catarina for the traits grain yield and plant cycle, which had a significant positivecorrelation of 0.26 (b) Based on the genotypes and environments studied the state can be divided in two macro-environments(MA1 and MA2) and four micro-environments (MI1, MI2, MI3 and MI4). The state of Santa Catarina may be roughly dividedin at least two macro-environments for the recommendation of new cultivars.
Experimental error in AFLP markers: consequence and estimative Erro experimental em marcadores AFLP: consequências e estimativas
Jefferson Luís Meirelles Coimbra,Altamir Frederico Guidolin,Maurício Marini Kopp,Juliano Garcia Bertoldo
Semina : Ciências Agrárias , 2012,
Abstract: The objective of this study was to estimate and to compare the Dice coefficients of dissimilarity through experimental error estimation, from the use of replications composed by plant bulks. The estimate of this coefficient can become more reliable and robust with the use of replications in the molecular analyses. This procedure favors either the tests of hypotheses or the evaluation of the contrasts of interest, according to the objective of the experiment. Also, to compare these estimates with each other and with the genetic dissimilarity estimate based on agronomical traits measured in the field. Among the evaluated variables (genetic and morphological), the distances estimated with base in the use of molecular versus morphological data evidenced 80% of agreement in the estimated values, compared to 5% (P < 0.05) when the replications were used, in the molecular analysis. This way, it is evident that the use of replications in molecular analyses, besides supplying an estimate of the experimental error, enables an immediate gain through the tests of hypotheses, increasing both the reliability of the estimates of the genetic parameters (i.e., repeatability), and the agreement between laboratory and field data. O objetivo deste trabalho foi estimar e comparar os coeficientes de dissimilaridades de DICE por meio da estimativa do erro experimental, proveniente da utiliza o de repeti es, que foram compostas por bulks de plantas e, comparar tanto estas estimativas entre si e com a estimativa da dissimilaridade genética baseada em caracteres agron micos avaliados por meio da experimenta o a campo. A estimativa deste coeficiente pode se tornar mais confiável e robusta com a utiliza o de repeti es nas análises moleculares. O uso de repeti es em análises moleculares favorece tanto os testes de hipóteses quanto a avalia o dos contrastes de interesse. A associa o entre as medidas avaliadas (genética e morfológica), com base na utiliza o de dados moleculares versus morfológicos evidenciou 80% de concordancia nos valores estimados, (P < 0,05) quando foram utilizadas as repeti es, na análise molecular. Desta forma, fica evidente que o emprego de repeti es em análises moleculares, além de fornecer uma estimativa do erro experimental, propicia um ganho imediato por meio dos testes de hipóteses; podendo incrementar desta maneira tanto a confiabilidade das estimativas dos parametros genéticos, como por exemplo, a repetibilidade, quanto à concordancia dos valores de laboratório e de experimentos de campo.
Effects of different doses of phosphorus during cultivation and length of subsequent storage on the cooking time of beans.
Juliano Garcia Bertoldo,Jefferson Luís Meirelles Coimbra,Altamir Frederico Guidolin,Fabiani da Rocha
Biotemas , 2009,
Abstract: This work aimed to verify the cooking times for beans cultivated under different doses of phosphorus and submitted to various periods of storage. The experiment was conducted in the experimental area of Molecular Genetics and Breeding Institute (IMEGEM) at UDESC, in Lages, SC, during the harvest of 2006/07. The sowing density was 200,000 plants per hectare. The experimental unit consisted of six rows of 5x3m in length, 0.5m apart, with a useful area of 12m2 per batch. The experimental delineation employed was that of random blocks in a 4x3x3 factorial scheme with three repetitions. Four genotypes of beans (Pérola, Iapar 81, IPR Uirapuru and IPR Chopim) were planted and added three doses of phosphorus (0, 100 and 200kg.ha-1 of P2O5) in the sowing line. After harvesting, storage times of 0, 45 and 90 days were tested. The evaluation of the cooking time of the grains was carried out using a Mattson cooker, adapted by Proctor and Watts (1987). The analysis of variance disclosed a significant effect over the cooking time response for the triple interaction between the factors cultivar (C), dose of phosphorus (P) and time of storage (A) (CxPxA). The time of storage had a strong influence on the time of cooking: the longer the storage, the greater the cooking time required. However, the use of phosphorus for fertilization was not significant in reducing the cooking time, with the exception of cultivar Iapar 81 that was treated with a dose of 100kg.ha-1 of P2O5, followed by storage of 45 days. This significant exception merits further study.
Effect of different salt concentrations on the reduction of bean (Phaseolus vulgaris) cooking time
Juliano Garcia Bertoldo,Jefferson Luís Meirelles Coimbra,Cristian Berto da Silveira,Diego Toaldo
Biotemas , 2008,
Abstract: The purpose of this work was to examine the effect of different saline concentrations on the cooking time of aged bean seeds. This experiment was conducted at the Molecular Genetics and Improvement Institute (IMEGEM / CAV), employing random block design with two repetitions, in a 2 x 4 factorial arrangement (two cultivars and four doses of NaCl). Two cultivars were tested, one belonging to the carioca group (Pérola) and the other belonging to the black group (Uirapuru). After weighing, the grains were imbibed in different sodium chloride (NaCl) concentrations (0g, 5g, 10g and 25g) for 12 hours at 25°C. Subsequently, these grains were submitted to a cooking test, using the Mattson cooking apparatus. It was then possible to determine the NaCl concentrations in which the cooking time presented a significant reduction. The Pérola cultivar cooking time was reduced by 31 minutes by the addition of 11g of NaCl and the Uirapuru cooking time was reduced by 25 minutes by the addition of 16.75g of NaCl.
Difficulties related to the use of tests of comparison of averages in scientific articles
Juliano Garcia Bertoldo,Jefferson Luís Meirelles Coimbra,Altamir Frederico Guidolin,Adelar Mantovani
Biotemas , 2008,
Abstract: The objective of this work was to verify the researcher’s main difficulties in the use of means comparison tests, as well as to propose alternatives for a better statistical inference. For a correct application of the statistical tests it is fundamental for the researcher to know the experimental design, the factors, the variables and the treatments that will constitute the work, because these are decisive in the choice of the statistical test. Two hundred and ninety-two scientific papers from plant sciences were revised. These papers were published in the Brazilian Qualis A journal, from 2000 until 2006. The papers were classified by their use of means comparison tests as i) appropriate, ii) partially appropriate, and iii) inappropriate. There were diffi culties involved in choosing the correct statistical procedure in relation to the experimental design used. The papers in which more than one factor was studied (75%) were classified as inadequate due to their abuse of the means comparison tests. On the other hand, 3% and 22% were classified as partially appropriate and appropriate, respectively.
Use of polymers in the technological quality of beans grains under store conditions Emprego de polímeros na qualidade tecnológica de gr os de feij o sob condi es de armazenamento
Juliano Garcia Bertoldo,Jefferson Luís Meirelles Coimbra,Leiri Daiane Barili,Naine Martins do Vale
Semina : Ciências Agrárias , 2010,
Abstract: The objective of this work was to evaluate the time of cooking of beans genotypes recovered with polymers throughout the storage time. The experiment was carried out in Lages, Santa Catarina, in which were used grains obtained from the 2006/07 harvest. It was used the complete randomized block design with three replications in an 2 x 3 x 3 factorial arrangemente (two genotypes - Pérola and IPR-Uirapuru; three times of storage - 0, 45 and 90 days and; three covered type – without recovered (standard), Carboximetilcelulose (CMC) and a blend (50/50) of Carboximetilcelulose and Alginato of sodium (MCM-AS). The cooking parameters were evaluated by using the Mattson cooker, adapted by Proctor e Watts (1987). There was a gradual increase in the time of cooking of the beans grains with increases on the storage time. There were differentiated behaviors among genotypes x polymers x storage time. Covering the genotype Pérola with the Carboximetilcelulose polymer reduces the cooking time during the storage. Covering the grains of the genotype Pérola with the blend of polymers Carboximetilcelulose and Alginato of sodium significant decreases the variation of the cooking time throughout the storage. O objetivo desse trabalho foi avaliar o caráter tempo de coc o em genótipos de feij o recobertos com polímeros ao longo do tempo de armazenamento. O experimento foi conduzido em Lages, Santa Catarina, sendo utilizadas sementes de feij o obtidas da safra 2006/07. O delineamento foi o de blocos ao acaso, com três repeti es num esquema fatorial 2 x 3 x 3 (dois genótipos - Pérola e IPR-Uirapuru; três tempos de armazenamento - 0, 45 e 90 dias e; três tipos de recobrimento – sem recobrimento (testemunha), Carboximetilcelulose (CMC) e uma mistura de polímeros na propor o 50/50 de Carboximetilcelulose e Alginato de sódio (CMC-AS). Foi realizada a avalia o do cozimento dos gr os com o uso do aparelho cozedor de Mattson, adaptado por Proctor e Watts (1987). Os resultados indicam um aumento gradativo no tempo de coc o dos gr os de feij o ao longo do armazenamento. Foi possível verificar comportamentos diferenciados entre genótipos x polímeros x armazenamento. O recobrimento com o polímero Carboximetilcelulose para o genótipo Pérola reduz significativamente o tempo de coc o durante o armazenamento. A peletiza o dos gr os do genótipo Pérola com a mistura dos polímeros na propor o 50/50 de Carboximetilcelulose e Alginato de sódio promove menor varia o no caráter tempo de coc o ao longo do armazenamento.
An approach to the decomposition of interaction in a factorial experiment with five factors
Rocha, Fabiani da;Vale, Naine Martins do;Barili, Leiri Daiana;Coimbra, Jefferson Luís Meirelles;Guidolin, Altamir Frederico;Bertoldo, Juliano Garcia;
Acta Scientiarum. Agronomy , 2012, DOI: 10.4025/actasciagron.v34i1.12104
Abstract: factorial experiments are widely employed in agricultural research. in these experiments, inferences related to the interaction between factors are fundamental. however, many researchers are still unable to analyze this type of experiment, and others do not consider the effect of interaction. this study aims to exemplify a scheme for unfolding the degrees of freedom and to demonstrate the relevance of this rearrangement when the interaction is significant. for these purposes, the response variable time of cooking bean grains was measured in minutes using a completely casualized experimental design, with two replications, arranged in a 2 x 2 x 3 x 2 x 2 factorial scheme (fivefold classification). the following factors were evaluated: bean genotypes (2 levels), salt type (2 levels), salt dose (3 levels), hydration time (2 levels) and storage time (2 levels). the results highlight the importance of unfolding the degrees of freedom of the interaction every time it is significant because the possibility of evaluating the interaction between factors leads to conclusions related to the dependence between the factors. these results are more coherent with biological systems, and the example shown provides a solid basis for minimizing errors in factorial experiments.
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