320 research outputs found

    Projeto editorial do Comitê de Publicações.

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    Bridging sd1 molecular knowledge with recent breeding strategies for the improvement of traditional rice varieties - a japonica case-study

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    The rice semidwarfing gene, sd1, also known as the “green revolution gene”, has been studied intensively due to its contribution to the increase of crop production. Although sd1 breeding was extensively applied since the 1960s, the recent advances in the molecular basis of this gene alloweddesigning a more precise breeding strategy - marker assisted backcrossing (MAB) - to track sd1 introgression in two traditional rice varieties. For selection of sd1 plants we first confirmed the efficiency of specific markers based on Os200 x 2 gene sequence. Background selection was alsoperformed with the help of microsatellites markers (SSR) and a total of 7 breeding lines were recovered containing a higher percentage of recurrent parent genome (RPG). Analysis of Covariance (ANCOVA) using mean progenitor plant height as covariate was performed to compare several agronomic and quality-related parameters in two different environments. The results suggest that plant height differs significantly between the two environments F(1, 220) = 155.336; p < 0.001. From the total variability ofplant height we could conclude that 73% is due to the genotype, while 10.4% depends on the environment. In addition, the percentage of RPG seems negatively correlated with plant height (p < 0.005). MAB and background selection thus revealed as useful tools to assist breeding forsemidwarfism in traditional rice varieties

    An Interesting Charmonium State Formation and Decay : ppˉ→1D2→1P1γp \bar p \to ^1D_2 \to ^1P_1 \gamma

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    Massless perturbative QCD forbids, at leading order, the exclusive annihilation of proton-antiproton into some charmonium states, which, however, have been observed in the ppˉp\bar p channel, indicating the significance of higher order and non perturbative effects in the few GeV energy region. The most well known cases are those of the 1S0^1S_0 (ηc\eta_c) and the 1P1^1P_1. The case of the 1D2^1D_2 is considered here and a way of detecting such a state through its typical angular distribution in the radiative decay 1D2→^1D_2 \to 1P1γ^1P_1 \gamma is suggested. Estimates of the branching ratio BR(1D2→ppˉ)BR(^1D_2 \to p\bar p), as given by a quark-diquark model of the nucleon, mass corrections and an instanton induced process are presented.Comment: 9 pages (no figures), Plain TeX, CBPF-NF-014/94, INFNCA-TH-94-

    MCHO – A new indicator for insulation conditions in transmission lines

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    AbstractConventionally monitoring operating conditions of a power transmission line is accomplished by periodic inspections along this line. This monitoring allows corrective maintenance by finding faults during the inspection. But in more efficient maintenance, predictive techniques that are characterized by real-time monitoring should be employed. Such predictive techniques allow for verifying the working status of the line by using normal working models to detect faults and fault models for diagnosis. This paper presents a study that used a mathematical model appropriate for application to predictive maintenance of transmission line segments at low cost, without the need for sensors distributed along the line, and presenting a new indicator of transmission line operation conditions. By tracking the leakage current of transmission lines, this model allows for estimating the current line insulation status. Once the current line insulation status is known, it is possible to compare it against other future status and verify the progress of the insulation conditions of that line. The model uses a new indicator, called MCHO, which can detect and diagnose both normal and abnormal operating conditions of a power transmission line. This new indicator is the capacitance of the harmonic frequencies of the transmission line leakage current. The model was validated through measurements obtained on a stretch of transmission line

    Salinity tolerance loci revealed in rice using high-throughput non-invasive phenotyping

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    High-throughput phenotyping produces multiple measurements over time, which require new methods of analyses that are flexible in their quantification of plant growth and transpiration, yet are computationally economic. Here we develop such analyses and apply this to a rice population genotyped with a 700k SNP high-density array. Two rice diversity panels, indica and aus, containing a total of 553 genotypes, are phenotyped in waterlogged conditions. Using cubic smoothing splines to estimate plant growth and transpiration, we identify four time intervals that characterize the early responses of rice to salinity. Relative growth rate, transpiration rate and transpiration use efficiency (TUE) are analysed using a new association model that takes into account the interaction between treatment (control and salt) and genetic marker. This model allows the identification of previously undetected loci affecting TUE on chromosome 11, providing insights into the early responses of rice to salinity, in particular into the effects of salinity on plant growth and transpiration.Nadia Al-Tamimi, Chris Brien, Helena Oakey, Bettina Berger, Stephanie Saade, Yung Shwen Ho, Sandra M. Schmöckel, Mark Tester and Sónia Negrã

    Multicentric Genome-Wide Association Study for Primary Spontaneous Pneumothorax

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    Despite elevated incidence and recurrence rates for Primary Spontaneous Pneumothorax (PSP), little is known about its etiology, and the genetics of idiopathic PSP remains unexplored. To identify genetic variants contributing to sporadic PSP risk, we conducted the first PSP genome-wide association study. Two replicate pools of 92 Portuguese PSP cases and of 129 age- and sex-matched controls were allelotyped in triplicate on the Affymetrix Human SNP Array 6.0 arrays. Markers passing quality control were ranked by relative allele score difference between cases and controls (|RASdiff|), by a novel cluster method and by a combined Z-test. 101 single nucleotide polymorphisms (SNPs) were selected using these three approaches for technical validation by individual genotyping in the discovery dataset. 87 out of 94 successfully tested SNPs were nominally associated in the discovery dataset. Replication of the 87 technically validated SNPs was then carried out in an independent replication dataset of 100 Portuguese cases and 425 controls. The intergenic rs4733649 SNP in chromosome 8 (between LINC00824 and LINC00977) was associated with PSP in the discovery (P = 4.07E-03, ORC[95% CI] = 1.88[1.22-2.89]), replication (P = 1.50E-02, ORC[95% CI] = 1.50[1.08-2.09]) and combined datasets (P = 8.61E-05, ORC[95% CI] = 1.65[1.29-2.13]). This study identified for the first time one genetic risk factor for sporadic PSP, but future studies are warranted to further confirm this finding in other populations and uncover its functional role in PSP pathogenesis
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