731 research outputs found

    Effect of Bacillus subtilis on fruit yield and quality in Actinidia deliciosa orchards infected with bacterial canker in the north of Portugal

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    Bacterial canker of kiwifruit, caused by Pseudomonas syringae pv. actinidae (Psa), a disease included in the EPPO A2 List, has been registered in the north of Portugal since 2010. The relationship between the bacterium and cultural practices, namely the application of the biological control agent Bacillus subtilis in kiwifruit orchards in Portugal, is poorly understood. The most damaging phase of the disease occurs in winter and involves damage of the main vine structure and overwintering canes, and also in spring, during pollen spread, thus reducing subsequent yield and fruit quality. The main objective of this study was to evaluate the effect of B. subtilis Serenade Max® on kiwifruit yield and quality in infected orchards of different ages. Two orchards (Actinidia deliciosa ‘Hayward’) with typical symptoms of Psa were selected for yield and quality assays. Thirty plants were selected from the young orchard (6 years old) and other 30 plants were selected from the old orchard (30 years old), both located in Valença, northwest Portugal. This work showed that the use of B. subtilis as a biological control agent against Psa did not affect overall kiwifruit quality, namely the longitudinal and length diameters of fruit, the total soluble solids content, firmness, pH, titratable acidity and dry matter, but contributed significantly to increased yield in the younger orchard compared with the older orchard.info:eu-repo/semantics/publishedVersio

    Efficacy of Bacillus subtilis for the control of Pseudomonas syringae pv. actinidiae under field conditions

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    Bacterial canker of kiwifruit, caused by Pseudomonas syringae pv. actinidiae (Psa), is a disease included on the EPPO A2 List because it is currently increasing in the Mediterranean region. Climatic conditions determine the multiplication and dispersal behavior of Psa and may influence its biological control (BC). However, information regarding the influence of climatic conditions on growth of the Psa bacterium in Portugal is scarce. The aims of this study were to relate the climatic conditions with the efficacy of Bacillus subtilis Serenade Max® in controlling the disease, to determine whether disease incidence increased over the growing season, and to monitor carry-over of disease from one season to the next. Two ‘Hayward’ orchards of Actinidia deliciosa of different ages, located in Valença, in the north of Portugal, were selected for BC assay. Thirty plants were randomly selected from a young orchard (6 years old) and another 30 plants from an old one (30 years old). Psa was identified and characterized by morphological, biochemical and molecular tests. The efficacy of B. subtilis was evaluated by disease incidence, and correlated to climatic conditions. A standardized leaf infection index (0-4 scale of symptoms) was used to determine disease severity. Monitoring of Psa symptoms was performed every 30 days, from June 2016 to April 2017. The severity of the disease decreased in the summer season, characterized by unfavorable conditions for Psa such as high temperatures and scarce precipitation. B. subtilis was partially effective in controlling Psa in the 6-year-old orchard, and showed no efficacy in the protection of leaves in the 30-year-old orchard. B. subtilis applied at flowering could be considered as a suitable solution for the control of Psa biovar 3 only for the new kiwifruit orchard (6 years old).info:eu-repo/semantics/publishedVersio

    Dirac-like Monopoles in Three Dimensions and Their Possible Influences on the Dynamics of Particles

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    Dirac-like monopoles are studied in three-dimensional Abelian Maxwell and Maxwell-Chern-Simons models. Their scalar nature is highlighted and discussed through a dimensional reduction of four-dimensional electrodynamics with electric and magnetic sources. Some general properties and similarities of them when are considered in Minkowski or Euclidian space are mentioned. However, by virtue of the structure of the space-time in which they are considered a number of differences among them take place. Furthermore, we pay attention to some consequences of these objects when acting upon usual particles. Among other subjects, special attention is given to the study of a Lorentz-violating non-minimal coupling between neutral fermions and the field generated by a monopole alone. In addition, an analogue of the Aharonov-Casher effect is discussed in this framework.Comment: 20 pages. Latex format. No figures. Accepted for publication in Phys. Rev.

    On the Cut-Off Prescriptions Associated with Power-Law Generalized Thermostatistics

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    We revisit the cut-off prescriptions which are needed in order to specify completely the form of Tsallis' maximum entropy distributions. For values of the Tsallis entropic parameter q>1q>1 we advance an alternative cut-off prescription and discuss some of its basic mathematical properties. As an illustration of the new cut-off prescription we consider in some detail the qq-generalized quantum distributions which have recently been shown to reproduce various experimental results related to high TcT_c superconductors

    Evaluation of Cardiac Autonomic Modulation Using Symbolic Dynamics after Cardiac Transplantation

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    Objective: To characterize the behavior of cardiac autonomic modulation in individuals with different times after orthotopic heart transplantation (HTx) using symbolic dynamics analysis. Methods: Sixty patients were evaluated after HTx. We recorded their instantaneous R-R intervals (RRi) by cardiac monitor Polar (R) RS800CX (TM) (Polar Electro Oy, Kempele, Finland) for 10 minutes. The same sequence of RRi with 256 consecutive beats was used to perform spectral analysis and symbolic dynamics analysis. We used hierarchical clustering to form groups. One-way analysis of variance (ANOVA) (with Holm-Sidak method) or one-way Kruskal-Wallis test (with Dunn's post-hoc test) was used to analyze the difference between groups. Linear correlation analysis between variables was performed using Pearson's or Spearman's tests. P-value < 0.05 was considered statistically significant. Results: The 0V% index increased, the 2UV% index and the normalized complexity index decreased with an increase of HTx postoperative time. There were a negative correlation between complexity indexes and 0V% and a positive correlation between complexity indexes and 2UV%. Conclusion: Symbolic dynamics indexes were able to show a specific cardiac autonomic modulation pattern for HTx recipients with different postoperative times

    Performance And Economic Analysis Of Finished Lambs In Feedlot

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    This study aimed to evaluate animal performance and economic performance of feedlot crossbred lambs (Santa Inês+ - Suffolk) fed different diets based on hay from Cynodon dactylon genotypes, through the use of financial measures considering only the period of feedlot, without relating it to the complete management cycle. A total of 30 intact crossbred Suffolk lambs, identified with earrings, with an average age of 90 days and an average body weight of 21.5 kg were used in this study. Diets were formulated using as treatments a standard concentrate and hay of the Cynodon dactylon genotypes Jiggs, Vaquero, Tifton 68, Coast-Cross, Tifton 85 and Russell in a 60:40 forage-to-concentrate ratio. The treatments were distributed in a randomized complete block design with five replicates. There were significant differences between diets in terms of total expenditure on food, and the highest values were obtained for the Jiggs genotype (BRL 48.96/animal). The animals fed diets based on Tifton 68 hay had a higher rate of return (2.16%) and profitability (34.63%) compared to the other diets. The use of diets based on Tifton 68 hay for feedlot lambs in the finishing phase brings higher economic returns compared to the remaining diets.37129330

    Transport spectroscopy in a time-modulated open quantum dot

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    We have investigated the time-modulated coherent quantum transport phenomena in a ballistic open quantum dot. The conductance GG and the electron dwell time in the dots are calculated by a time-dependent mode-matching method. Under high-frequency modulation, the traversing electrons are found to exhibit three types of resonant scatterings. They are intersideband scatterings: into quasibound states in the dots, into true bound states in the dots, and into quasibound states just beneath the subband threshold in the leads. Dip structures or fano structures in GG are their signatures. Our results show structures due to 2ω\hbar\omega intersideband processes. At the above scattering resonances, we have estimated, according to our dwell time calculation, the number of round-trip scatterings that the traversing electrons undertake between the two dot openings.Comment: 8 pages, 5 figure

    On the Number of Zeros of Abelian Integrals: A Constructive Solution of the Infinitesimal Hilbert Sixteenth Problem

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    We prove that the number of limit cycles generated by a small non-conservative perturbation of a Hamiltonian polynomial vector field on the plane, is bounded by a double exponential of the degree of the fields. This solves the long-standing tangential Hilbert 16th problem. The proof uses only the fact that Abelian integrals of a given degree are horizontal sections of a regular flat meromorphic connection (Gauss-Manin connection) with a quasiunipotent monodromy group.Comment: Final revisio
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