Evaluation of the coefficient of variation as a measure of precision to the experiments with citrus

O presente trabalho foi executado com dados de coeficientes de variação (CV) de vários trabalhos publicados no Brasil, com ênfase em citricultura, e suas variáveis mais correntemente estudadas (altura e produção de frutos por planta; diâmetro e peso dos frutos; rendimento, pH, "ratio", sólidos solúveis e acidez do suco). O objetivo foi o de propor faixas de CV que orientem o pesquisador na avaliação de cada variável. Após o agrupamento dos dados, procedeu-se ao teste de normalidade de Lilliefors, revelando que todas as variáveis utilizadas tiveram distribuição aproximadamente normal. Com isso, através de tabela sugerida para trabalhos com espécies florestais que relaciona a média e o desvio padrão [CV±√Var(CV)], foi construída uma tabela como sugestão de intervalo de CV, referente a cada variável em questão. A variável número de frutos por planta foi a que apresentou maiores valores do coeficiente, e as variáveis relacionadas ao suco (obtidas em laboratório), de forma geral, foram as que apresentaram menores CV.The present study was developed with values of coefficients of variation (CV) taken from various works published in Brazil, with emphasis on fruit culture, and their variables most currently studied (height and fruit production per plant; diameter and fruit weight; yield, pH, "ratio", soluble solids and juice acidity). The objective was to propose CV bands which orient the researcher in the evaluation of each variable. After data grouping, a test of normality of Lilliefors was made, which revealed that all the variables utilized had an approximately normal distribution. With this, by means of a table based on work with forest species which establishes the medium and the standard deviation [CV±√Var(CV)], a table was constructed with suggested intervals of CV for each variable in question. The number of fruits per plant variable was that which presented larger coefficient values, and the values related to the juice (obtained in the laboratory) were those which generally presented the smaller CV

Rapid and sensitive detection of Citrus Bacterial Canker by loop-mediated isothermal amplification combined with simple visual evaluation methods

<p>Abstract</p> <p>Background</p> <p>Citrus Bacterial Canker (CBC) is a major, highly contagious disease of citrus plants present in many countries in Asia, Africa and America, but not in the Mediterranean area. There are three types of Citrus Bacterial Canker, named A, B, and C that have different genotypes and posses variation in host range within citrus species. The causative agent for type A CBC is <it>Xanthomonas citri </it>subsp. <it>citri</it>, while <it>Xanthomonas fuscans </it>subsp. <it>aurantifolii</it>, strain B causes type B CBC and <it>Xanthomonas fuscans </it>subsp. <it>aurantifolii </it>strain C causes CBC type C. The early and accurate identification of those bacteria is essential for the protection of the citrus industry. Detection methods based on bacterial isolation, antibodies or polymerase chain reaction (PCR) have been developed previously; however, these approaches may be time consuming, laborious and, in the case of PCR, it requires expensive laboratory equipment. Loop-mediated isothermal amplification (LAMP), which is a novel isothermal DNA amplification technique, is sensitive, specific, fast and requires no specialized laboratory equipment.</p> <p>Results</p> <p>A loop-mediated isothermal amplification assay for the diagnosis of Citrus Bacterial Canker (CBC-LAMP) was developed and evaluated. DNA samples were obtained from infected plants or cultured bacteria. A typical ladder-like pattern on gel electrophoresis was observed in all positive samples in contrast to the negative controls. In addition, amplification products were detected by visual inspection using SYBRGreen and using a lateral flow dipstick, eliminating the need for gel electrophoresis. The sensitivity and specificity of the assay were evaluated in different conditions and using several sample sources which included purified DNA, bacterium culture and infected plant tissue. The sensitivity of the CBC-LAMP was 10 fg of pure <it>Xcc </it>DNA, 5 CFU in culture samples and 18 CFU in samples of infected plant tissue. No cross reaction was observed with DNA of other phytopathogenic bacteria. The assay was capable of detecting CBC-causing strains from several geographical origins and pathotypes.</p> <p>Conclusions</p> <p>The CBC-LAMP technique is a simple, fast, sensitive and specific method for the diagnosis of Citrus Bacterial Canker. This method can be useful in the phytosanitary programs of the citrus industry worldwide.</p

Efeito da sucessão de cultura e do preparo do solo sobre o rendimento do arroz de sequeiro

The objective of this work was to study the effect of different crop successions (S1: rice-common bean; S2: soybean-wheat-soybean-common bean-rice-common bean; S3: rice associated with Calopogonium muconoides-common bean; and S4: corn-common bean-corn-common bean-rice-common bean) and systems of soil preparation (P1: moldboard plough/harrow disc; P2: moldboard plough; P3: harrow disc and P4: no-tillage) on grain yield and on component yield of upland rice (Oryza sativa L.). The work was conducted at Embrapa-Centro Nacional de Pesquisa de Arroz e Feijão (CNPAF), Goiânia, Goiás, Brazil, in a Dark Red Latosol, for three consecutive years. A complete randomized design was used. Rice was cultivated annually in sucessions S1 and S3 and every three years in S2 and S4 in the months of November and December. There was a reduction in grain yield of rice during the three successives cultivation, and Calopogonium muconoides was prejudicial for yield of rice crop. Higher yield of rice was obtained when it was cultivated in succession every three years. Leaf area index and nutrients absorption were lower in successions where rice was cultivated annually. The highest grain yield was obtained under no-tillage treatment.O objetivo deste trabalho foi estudar os efeitos de diferentes sucessões de cultura (S1: arroz-feijão; S2: soja-trigo-soja-feijão-arroz-feijão; S3: arroz consorciado com calopogônio-feijão; e S4: milho-feijão-milho-feijão-arroz-feijão) e sistemas de preparo do solo (P1: arado/grade aradora; P2: arado; P3: grade aradora; e P4: plantio direto) sobre o rendimento de grãos e os componentes de rendimento do arroz de sequeiro (Oryza sativa L.). O trabalho foi conduzido na Embrapa-Centro Nacional de Pesquisa de Arroz e Feijão (CNPAF), em Goiânia, GO, em Latossolo Vermelho-Escuro, textura argilosa, por três anos consecutivos. O delineamento experimental foi o inteiramente casualizado. O arroz foi cultivado anualmente nas sucessões S1 e S3, e trienalmente nas S2 e S4, nos meses de novembro - dezembro. Houve diminuição no rendimento de grãos de arroz nos três cultivos consecutivos na mesma área, e o calopogônio em consórcio prejudicou o rendimento do arroz. Os maiores rendimentos de grãos foram obtidos nas sucessões em que o arroz foi cultivado trienalmente. O índice de área foliar e a absorção de nutrientes foram mais baixos nas sucessões em que o arroz foi cultivado anualmente. O maior rendimento de grãos foi obtido no tratamento plantio direto

Evaluating Lean Healthcare implementation with data mining: opportunities and improvements in emergency services

The waiting time for care in emergency services impacts overcrowding. The Fast Track method contributes to reducing this waiting time. The objective of this study was to evaluate the problems identified and improvements made in emergency services through the execution of the Lean Healthcare project. With the qualitative research approach, data mining allowed reaching results that demonstrated similar problems in emergency services in eight federative units. The improvements implemented contributed to the reduction of patient waiting time. Data mining allowed evaluating groups with similar characteristics, which showed the correlation between the problems encountered and the improvements made in the emergency services

Mutation in the xpsD gene of Xanthomonas axonopodis pv. citri affects cellulose degradation and virulence

The Gram-negative bacterium Xanthomonas axonopodis pv. citri, the causal agent of citrus canker, is a major threat to the citrus industry worldwide. Although this is a leaf spot pathogen, it bears genes highly related to degradation of plant cell walls, which are typically found in plant pathogens that cause symptoms of tissue maceration. Little is known on Xac capacity to cause disease and hydrolyze cellulose. We investigated the contribution of various open reading frames on degradation of a cellulose compound by means of a global mutational assay to selectively screen for a defect in carboxymethyl cellulase (CMCase) secretion in X. axonopodis pv. citri. Screening on CMC agar revealed one mutant clone defective in extracellular glycanase activity, out of nearly 3,000 clones. The insertion was located in the xpsD gene, a component of the type II secretion system (T2SS) showing an influence in the ability of Xac to colonize tissues and hydrolyze cellulose. In summary, these data show for the first time, that X. axonopodis pv. citri is capable of hydrolyzing cellulose in a T2SS-dependent process. Furthermore, it was demonstrated that the ability to degrade cellulose contributes to the infection process as a whole

Differential expression of pathogenicity- and virulence-related genes of Xanthomonas axonopodis pv. citri under copper stress

In this study, we used real-time quantitative PCR (RT-qPCR) to evaluate the expression of 32 genes of Xanthomonas axonopodis pv. citri related to pathogenicity and virulence that are also involved in copper detoxification. Nearly all of the genes were up-regulated, including copA and copB. Two genes homologous to members of the type II secretion system (xcsH and xcsC) and two involved in the degradation of plant cell wall components (pglA and pel) were the most expressed in response to an elevated copper concentration. The type II secretion system (xcs operon) and a few homologues of proteins putatively secreted by this system showed enhanced expression when the bacteria were exposed to a high concentration of copper sulfate. The enhanced expression of the genes of secretion II system during copper stress suggests that this pathway may have an important role in the adaptative response of X. axonopodis pv. citri to toxic compounds. These findings highlight the potential role of these genes in attenuating the toxicity of certain metals and could represent an important means of bacterial resistance against chemicals used to control diseases

Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

The inclusive and dijet production cross-sections have been measured for jets containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The measurements use data corresponding to an integrated luminosity of 34 pb^-1. The b-jets are identified using either a lifetime-based method, where secondary decay vertices of b-hadrons in jets are reconstructed using information from the tracking detectors, or a muon-based method where the presence of a muon is used to identify semileptonic decays of b-hadrons inside jets. The inclusive b-jet cross-section is measured as a function of transverse momentum in the range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet cross-section is measured as a function of the dijet invariant mass in the range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets and the angular variable chi in two dijet mass regions. The results are compared with next-to-leading-order QCD predictions. Good agreement is observed between the measured cross-sections and the predictions obtained using POWHEG + Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet cross-section. However, it does not reproduce the measured inclusive cross-section well, particularly for central b-jets with large transverse momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final version published in European Physical Journal

Search for displaced vertices arising from decays of new heavy particles in 7 TeV pp collisions at ATLAS

We present the results of a search for new, heavy particles that decay at a significant distance from their production point into a final state containing charged hadrons in association with a high-momentum muon. The search is conducted in a pp-collision data sample with a center-of-mass energy of 7 TeV and an integrated luminosity of 33 pb^-1 collected in 2010 by the ATLAS detector operating at the Large Hadron Collider. Production of such particles is expected in various scenarios of physics beyond the standard model. We observe no signal and place limits on the production cross-section of supersymmetric particles in an R-parity-violating scenario as a function of the neutralino lifetime. Limits are presented for different squark and neutralino masses, enabling extension of the limits to a variety of other models.Comment: 8 pages plus author list (20 pages total), 8 figures, 1 table, final version to appear in Physics Letters

Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio