622 research outputs found

    Hot-water treatment of dormant grape cuttings: Its effects on Agrobacterium tumefaciens and on grafting and growth of vine

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    Hot-water treatment (50°C for 20-30 min) was carried out to confirm its efficacy in eradicating Agrobacterium tumefaciens biovar 3 (AT3) in symptomless grape cuttings.After the forcing period, analyses of callus from cuttings of grape cvs Albana, Lambrusco Grasparossa, Rulander and Fortana, and from their graft combinations with the rootstocks 420A, 41B, 5BB and 1103P, revealed the low infection level in the grape material used. Dormant scion and rootstock cuttings treated identically in the U.S. gave similar results. Despite this, it was possible to confirm the efficacy of thermotherapy in eradicating the pathogen.An assessment was also made of the effect of treatment on growth parameters of grafted vines in the greenhouse and after 8 months in a field nursery. The effect of hot-water treatment on the vitality and growth of vines varied with the different scion-rootstock combinations. Treatment did not generally have detrimental effects on vitality; there were some negative effects on graft-take. The number and length of canes, as well as the diameter of the trunks, increased in most instances.The treatments and times usually did not affect bud survival and, in most cases, increased the level of callus formation at the base of cuttings.

    Portable Soil EC - Development of an electronic device for determining soil electrical conductivity.

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    Decision-making in agriculture demands continuous monitoring, a factor that propels the advancement of tools within Agriculture 4.0. In this context, understanding soil characteristics is essential. Electrical conductivity (EC) sensors play a pivotal role in this comprehension. Given this backdrop, the core motivation of this research was developing an accessible and effective electronic device to measure the apparent EC of the soil. It provides features like geolocation, recording of the date and time of collection, expandable digital storage capacity, and USB connectivity, making it a valuable tool for field surveys in the application of PA. The project focused on developing an electronic circuit, starting with a schematic detailing the component connections. Reading the manufacturer's data sheets is essential to avoid mistakes. Subsequently, the printed circuit board layout was designed, considering the optimization of space and centralized positioning of the main components. The present research yielded that the portable EC meter, which demonstrates versatility in its application, is easy to handle and offers promising results for field application. The name proposed by the developers is Portable Soil EC. Field testing revealed significant variability in the soil EC in apple plantations

    Novel pathogen-specific primers for the detection of Agrobacterium vitis and Agrobacterium tumefaciens

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    To detect agrobacteria causing crown gall disease of grapevine novel virulence and oncogene specific primer combinations were tested on Agrobacterium vitis and Agrobacterium tumefaciens strains including most opine types found in grapevines. Reproducible detection of all the tested pathogens in a single reaction was only possible with multiplex PCR using mixtures of virulence-, or oncogene specific primers. A primer combination including pehA, virF and virD2 gene-specific oligonucleotides amplified the corresponding fragments from nearly all strains included and distinguished A. vitis and A. tumefaciens strains carrying octopine or nopaline pTis and A. vitis vitopine strains. A second set of primers designed to amplify the T-DNA auxin genes iaaH and iaaM detected all of the tested pathogens and, as in the case of virF-, and virD2-specific primers, A. vitis vitopine strains formed also a distinct group. These data were further confirmed using opine synthase-, or 6b gene-specific primers that also allowed the identification and distinction of octopine and nopaline as well as vitopine isolates of A. vitis. Thus, a wide range of agrobacteria occurring on grapevine were detected and identified. On the other hand, our results confirm that vitopine-type agrobacteria form a distinct group within the genus Agrobacterium.

    A New Measurement of Kaonic Hydrogen X rays

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    The KˉN\bar{K}N system at threshold is a sensitive testing ground for low energy QCD, especially for the explicit chiral symmetry breaking. Therefore, we have measured the KK-series x rays of kaonic hydrogen atoms at the DAΦ\PhiNE electron-positron collider of Laboratori Nazionali di Frascati, and have determined the most precise values of the strong-interaction energy-level shift and width of the 1s1s atomic state. As x-ray detectors, we used large-area silicon drift detectors having excellent energy and timing resolution, which were developed especially for the SIDDHARTA experiment. The shift and width were determined to be ϵ1s=283±36±6(syst)\epsilon_{1s} = -283 \pm 36 \pm 6 {(syst)} eV and Γ1s=541±89(stat)±22(syst)\Gamma_{1s} = 541 \pm 89 {(stat)} \pm 22 {(syst)} eV, respectively. The new values will provide vital constraints on the theoretical description of the low-energy KˉN\bar{K}N interaction.Comment: 5 figures, submitted to Physics Letters

    APPLESHOW: sistema de informação geográfica para mapeamento da qualidade de maçã.

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    A agricultura de precisão vem se destacando nos últimos anos como a maneira de proporcionar ao produtor rural uma nova forma de gerenciamento da sua atividade, proporcionando melhores opções de tomada de decisão em busca de melhores relações de custo e benefício. A fruticultura brasileira, de um modo geral, era uma atividade que estava atrasada em relação ao uso da agricultura de precisão, principalmente se comparado às culturas de grãos, uma vez que os produtores careciam de softwares de apoio à tomada de decisão, dentre outras necessidades.bitstream/item/211579/1/Doc116b.pd

    An Optimal Self-Stabilizing Firing Squad

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    Consider a fully connected network where up to tt processes may crash, and all processes start in an arbitrary memory state. The self-stabilizing firing squad problem consists of eventually guaranteeing simultaneous response to an external input. This is modeled by requiring that the non-crashed processes "fire" simultaneously if some correct process received an external "GO" input, and that they only fire as a response to some process receiving such an input. This paper presents FireAlg, the first self-stabilizing firing squad algorithm. The FireAlg algorithm is optimal in two respects: (a) Once the algorithm is in a safe state, it fires in response to a GO input as fast as any other algorithm does, and (b) Starting from an arbitrary state, it converges to a safe state as fast as any other algorithm does.Comment: Shorter version to appear in SSS0

    Shedding New Light on Kaon-Nucleon/Nuclei Interaction and Its Astrophysical Implications with the AMADEUS Experiment at DAFNE

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    The AMADEUS experiment deals with the investigation of the low-energy kaon-nuclei hadronic interaction at the DA{\Phi}NE collider at LNF-INFN, which is fundamental to respond longstanding questions in the non-perturbative QCD strangeness sector. The antikaon-nucleon potential is investigated searching for signals from possible bound kaonic clusters, which would open the possibility for the formation of cold dense baryonic matter. The confirmation of this scenario may imply a fundamental role of strangeness in astrophysics. AMADEUS step 0 consisted in the reanalysis of 2004/2005 KLOE dataset, exploiting K- absorptions in H, 4He, 9Be and 12C in the setup materials. In this paper, together with a review on the multi-nucleon K- absorption and the particle identification procedure, the first results on the {\Sigma}0-p channel will be presented including a statistical analysis on the possible accomodation of a deeply bound stateComment: 6 pages, 2 figure, 1 table, HADRON 2015 conferenc

    First measurement of kaonic helium-3 X-rays

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    The first observation of the kaonic 3He 3d - 2p transition was made using slow K- mesons stopped in a gaseous 3He target. The kaonic atom X-rays were detected with large-area silicon drift detectors using the timing information of the K+K- pairs of phi-meson decays produced by the DAFNE e+e- collider. The strong interaction shift of the kaonic 3He 2p state was determined to be -2+-2 (stat)+-4 (syst) eV.Comment: Accepted for publication in Phys. Lett.
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