857 research outputs found

    Grain Yield Stability of Cereal-Legume Intercrops Is Greater Than Sole Crops in More Productive Conditions

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    The intercropping of two or more crop species on the same piece of land at a given time has been hypothesized to enhance crop yield stability. To address this hypothesis, we assessed the grain yield stability of various barley-pea and wheat-faba bean mixtures grown in seven experimental field trials (locations) across Europe during two years with contrasting weather (2017 and 2018). Three different yield stability measures were used, all based on the expected yield variability of the mixture components grown as sole crops, and the corresponding observed yield variability of the same components grown in 50:50 mixtures in a replacement design. Stability indices were calculated as ratios between the expected and observed variabilities, with values > 1 indicating greater stability of the intercrops. Mean grain yields tended to be higher in intercrops than sole crops. However, in contrast to our hypothesis, the observed (intercrop) yield stability was similar or lower than the expected (sole crop) stability in most locations except one. Furthermore, yield stability significantly increased with increasing mean yields when assessed across differentially productive locations. The results are relevant for the designing of intercropping systems as a means to increase yield stability and the resilience of cropping systems.This research was funded by the DIVERSify project, a grant from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 727284. MR was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation)—420661662. A.J.K. and A.C.N. are also supported by the strategic research programme funded by the Scottish Government’s Rural and Environment Science and Analytical Services Division.Peer reviewe

    Evidence for an η<sub>c</sub>(1<i>S</i>)π− resonance in <i>B</i><sup>0</sup>→η<sub>c</sub>(1<i>S</i>)<i>K</i><sup>+</sup>π<sup>−</sup> decays

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    A Dalitz plot analysis of B0→ηc(1S)K+π−B^0 \to \eta_c(1S) K^+\pi^- decays is performed using data samples of pppp collisions collected with the LHCb detector at centre-of-mass energies of s=7, 8\sqrt{s}=7,~8 and 1313 TeV, corresponding to a total integrated luminosity of 4.7 fb−14.7~\text{fb}^{-1}. A satisfactory description of the data is obtained when including a contribution representing an exotic ηc(1S)π−\eta_c(1S) \pi^- resonant state. The significance of this exotic resonance is more than three standard deviations, while its mass and width are 4096±20 −22+184096 \pm 20~^{+18}_{-22} MeV and 152±58 −35+60152 \pm 58~^{+60}_{-35} MeV, respectively. The spin-parity assignments JP=0+J^P=0^+ and JP=1−J^{P}=1^- are both consistent with the data. In addition, the first measurement of the B0→ηc(1S)K+π−B^0 \to \eta_c(1S) K^+\pi^- branching fraction is performed and gives B(B0→ηc(1S)K+π−)=(5.73±0.24±0.13±0.66)×10−4\displaystyle \mathcal{B}(B^0 \to \eta_c(1S) K^+\pi^-) = (5.73 \pm 0.24 \pm 0.13 \pm 0.66) \times 10^{-4}, where the first uncertainty is statistical, the second systematic, and the third is due to limited knowledge of external branching fractions

    Les droits disciplinaires des fonctions publiques : « unification », « harmonisation » ou « distanciation ». A propos de la loi du 26 avril 2016 relative à la déontologie et aux droits et obligations des fonctionnaires

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    The production of tt‟ , W+bb‟ and W+cc‟ is studied in the forward region of proton–proton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98±0.02 fb−1 . The W bosons are reconstructed in the decays W→ℓΜ , where ℓ denotes muon or electron, while the b and c quarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions.The production of tt‟t\overline{t}, W+bb‟W+b\overline{b} and W+cc‟W+c\overline{c} is studied in the forward region of proton-proton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98 ±\pm 0.02 \mbox{fb}^{-1}. The WW bosons are reconstructed in the decays W→ℓΜW\rightarrow\ell\nu, where ℓ\ell denotes muon or electron, while the bb and cc quarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions
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