52 research outputs found

    Expressed sequence tags from Atta laevigata and identification of candidate genes for the control of pest leaf-cutting ants

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    <p>Abstract</p> <p>Background</p> <p>Leafcutters are the highest evolved within Neotropical ants in the tribe Attini and model systems for studying caste formation, labor division and symbiosis with microorganisms. Some species of leafcutters are agricultural pests controlled by chemicals which affect other animals and accumulate in the environment. Aiming to provide genetic basis for the study of leafcutters and for the development of more specific and environmentally friendly methods for the control of pest leafcutters, we generated expressed sequence tag data from <it>Atta laevigata</it>, one of the pest ants with broad geographic distribution in South America.</p> <p>Results</p> <p>The analysis of the expressed sequence tags allowed us to characterize 2,006 unique sequences in <it>Atta laevigata</it>. Sixteen of these genes had a high number of transcripts and are likely positively selected for high level of gene expression, being responsible for three basic biological functions: energy conservation through redox reactions in mitochondria; cytoskeleton and muscle structuring; regulation of gene expression and metabolism. Based on leafcutters lifestyle and reports of genes involved in key processes of other social insects, we identified 146 sequences potential targets for controlling pest leafcutters. The targets are responsible for antixenobiosis, development and longevity, immunity, resistance to pathogens, pheromone function, cell signaling, behavior, polysaccharide metabolism and arginine kynase activity.</p> <p>Conclusion</p> <p>The generation and analysis of expressed sequence tags from <it>Atta laevigata </it>have provided important genetic basis for future studies on the biology of leaf-cutting ants and may contribute to the development of a more specific and environmentally friendly method for the control of agricultural pest leafcutters.</p

    Observation of B(s)0→J/ψpp¯ decays and precision measurements of the B(s)0 masses

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    The first observation of the decays B 0 ( s ) → J / ψ p ¯ p is reported, using proton-proton collision data corresponding to an integrated luminosity of 5.2     fb − 1 , collected with the LHCb detector. These decays are suppressed due to limited available phase space, as well as due to Okubo-Zweig-Iizuka or Cabibbo suppression. The measured branching fractions are B ( B 0 → J / ψ p ¯ p ) = [ 4.51 ± 0.40 ( stat ) ± 0.44 ( syst ) ] × 10 − 7 , B ( B 0 s → J / ψ p ¯ p ) = [ 3.58 ± 0.19 ( stat ) ± 0.39 ( syst ) ] × 10 − 6 . For the B 0 s meson, the result is much higher than the expected value of O ( 10 − 9 ) . The small available phase space in these decays also allows for the most precise single measurement of both the B 0 mass as 5279.74 ± 0.30 ( stat ) ± 0.10 ( syst )     MeV and the B 0 s mass as 5366.85 ± 0.19 ( stat ) ± 0.13 ( syst )     MeV

    Observation of the decay Λ <sub>b</sub> <sup>0</sup>  → ψ(2S)pπ<sup>−</sup>

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    International audienceThe Cabibbo-suppressed decay Λb0_{b}^{0}  → ψ(2S)pπ^{−} is observed for the first time using a data sample collected by the LHCb experiment in proton-proton collisions corresponding to 1.0, 2.0 and 1.9 fb1^{−1} of integrated luminosity at centre-of-mass energies of 7, 8 and 13 TeV, respectively. The ψ(2S) mesons are reconstructed in the μ+^{+}μ^{−} final state. The branching fraction with respect to that of the Λb0_{b}^{0}  → ψ(2S)pK^{−} decay mode is measured to b

    Evidence for an nc(1S)ff- resonance in B0 yc(1S)K+ decays

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    A Dalitz plot analysis of B0→ηc(1S)K+π- decays is performed using data samples of pp collisions collected with the LHCb detector at centre-of-mass energies of s=7,8 and 13TeV , corresponding to a total integrated luminosity of 4.7fb-1 . A satisfactory description of the data is obtained when including a contribution representing an exotic ηc(1S)π- resonant state. The significance of this exotic resonance is more than three standard deviations, while its mass and width are 4096±20-22+18MeV and 152±58-35+60MeV , respectively. The spin-parity assignments JP=0+ and JP=1- are both consistent with the data. In addition, the first measurement of the B0→ηc(1S)K+π- branching fraction is performed and gives B(B0→ηc(1S)K+π-)=(5.73±0.24±0.13±0.66)×10-4, where the first uncertainty is statistical, the second systematic, and the third is due to limited knowledge of external branching fractions

    Observation of B+c → D0K+ decays

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    Using proton-proton collision data corresponding to an integrated luminosity of 3.0 fb−1, recorded by the LHCb detector at center-of-mass energies of 7 and 8 TeV, the B+ c → D0K+ decay is observed with a statistical significance of 5.1 standard deviations. By normalizing to B+ → D¯ 0π+ decays, a measurement of the branching fraction multiplied by the production rates for B+ c relative to B+ mesons in the LHCb acceptance is obtained, R D 0 K = ( f c / f u ) × B ( B + c → D 0 K + ) = ( 9. 3 + 2.8 − 2.5 ± 0.6 ) × 10 − 7, where the first uncertainty is statistical and the second is systematic. This decay is expected to proceed predominantly through weak annihilation and penguin amplitudes, and is the first B+ c decay of this nature to be observed

    Measurement of the B_{s}^{0}→μ^{+}μ^{-} Branching Fraction and Effective Lifetime and Search for B^{0}→μ^{+}μ^{-} Decays.

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    A search for the rare decays B_{s}^{0}→μ^{+}μ^{-} and B^{0}→μ^{+}μ^{-} is performed at the LHCb experiment using data collected in pp collisions corresponding to a total integrated luminosity of 4.4  fb^{-1}. An excess of B_{s}^{0}→μ^{+}μ^{-} decays is observed with a significance of 7.8 standard deviations, representing the first observation of this decay in a single experiment. The branching fraction is measured to be B(B_{s}^{0}→μ^{+}μ^{-})=(3.0±0.6_{-0.2}^{+0.3})×10^{-9}, where the first uncertainty is statistical and the second systematic. The first measurement of the B_{s}^{0}→μ^{+}μ^{-} effective lifetime, τ(B_{s}^{0}→μ^{+}μ^{-})=2.04±0.44±0.05  ps, is reported. No significant excess of B^{0}→μ^{+}μ^{-} decays is found, and a 95% confidence level upper limit, B(B^{0}→μ^{+}μ^{-})<3.4×10^{-10}, is determined. All results are in agreement with the standard model expectations

    Amplitude analysis of the B0 (s)! K0K0 decays and measurement of the branching fraction of the B0! K0K0 decay

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    The B0K0K0B^0 \to K^{*0} \overline{K}^{*0} and Bs0K0K0B^0_s \to K^{*0} \overline{K}^{*0} decays are studied using proton-proton collision data corresponding to an integrated luminosity of 3fb1^{-1}. An untagged and time-integrated amplitude analysis of B(s)0(K+π)(Kπ+)B^0_{(s)} \to (K^+\pi^-)(K^-\pi^+) decays in two-body invariant mass regions of 150 MeV/c2/c^2 around the K0K^{*0} mass is performed. A stronger longitudinal polarisation fraction in the B0K0K0{B^0 \to K^{*0} \overline{K}^{*0}} decay, fL=0.724±0.051(stat)±0.016(syst){f_L = 0.724 \pm 0.051 \,({\rm stat}) \pm 0.016 \,({\rm syst})}, is observed as compared to fL=0.240±0.031(stat)±0.025(syst){f_L = 0.240 \pm 0.031 \,({\rm stat}) \pm 0.025 \,({\rm syst})} in the Bs0K0K0{B^0_s\to K^{*0} \overline{K}^{*0}} decay. The ratio of branching fractions of the two decays is measured and used to determine B(B0K0K0)=(8.0±0.9(stat)±0.4(syst))×107\mathcal{B}(B^0 \to K^{*0} \overline{K}^{*0}) = (8.0 \pm 0.9 \,({\rm stat}) \pm 0.4 \,({\rm syst})) \times 10^{-7}.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2019-004.html (LHCb public pages

    First measurement of the CPCP-violating phase φsddφ_s^{d\overline{d}} in Bs0(K+π)(Kπ+)B_s^0\to(K^+π^-)(K^-π^+) decays

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    A flavour-tagged decay-time-dependent amplitude analysis of Bs0(K+π)(Kπ+)B_s^0\to(K^+\pi^-)(K^-\pi^+) decays is presented in the K±πK^{\pm}\pi^{\mp} mass range from 750 to 1600 MeV/c2/c^2. The analysis uses pppp collision data collected with the LHCb detector at centre-of-mass energies of 77 and 88 TeV, corresponding to an integrated luminosity of 3.03.0 fb1^{-1}. Several quasi-two-body decay modes are considered, corresponding to K±πK^{\pm}\pi^{\mp} combinations with spin 0, 1 and 2, which are dominated by the K0(800)0K_0^*(800)^0 and K0(1430)0K_0^*(1430)^0, the K(892)0K^*(892)^0 and the K2(1430)0K_2^*(1430)^0 resonances, respectively. The longitudinal polarisation fraction for the Bs0K(892)0K(892)0B_s^0\to K^*(892)^0\overline{K}^*(892)^0 decay is measured as fL=0.208±0.032±0.046f_L=0.208 \pm 0.032 \pm 0.046, where the first uncertainty is statistical and the second is systematic. The first measurement of the mixing-induced CPCP-violating phase, ϕsdd\phi_s^{d\overline{d}}, in bddsb\to d\overline{d}s transitions is performed, yielding a value of ϕsdd=0.10\phi_s^{d\overline{d}}=-0.10 ±\pm 0.130.13 (stat) ±\pm 0.140.14 (syst) rad

    Search for Lepton-Universality Violation in B^{+}→K^{+}ℓ^{+}ℓ^{-} Decays.

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    A measurement of the ratio of branching fractions of the decays B^{+}→K^{+}μ^{+}μ^{-} and B^{+}→K^{+}e^{+}e^{-} is presented. The proton-proton collision data used correspond to an integrated luminosity of 5.0  fb^{-1} recorded with the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV. For the dilepton mass-squared range 1.1<q^{2}<6.0  GeV^{2}/c^{4} the ratio of branching fractions is measured to be R_{K}=0.846_{-0.054}^{+0.060}_{-0.014}^{+0.016}, where the first uncertainty is statistical and the second systematic. This is the most precise measurement of R_{K} to date and is compatible with the standard model at the level of 2.5 standard deviations

    Measurement of the Ratio of the B-0 -> D*(-)iota(+)v(iota) and B-0 -> D*(-) mu(+)v(mu) Branching Fractions Using Three-Prong tau-Lepton Decays

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    The ratio of branching fractions R(D)B(B0Dτ+ντ)/B(B0Dμ+νμ){\cal{R}}(D^{*-})\equiv {\cal{B}}(B^0 \to D^{*-} \tau^+ \nu_{\tau})/{\cal{B}}(B^0 \to D^{*-} \mu^+\nu_{\mu}) is measured using a data sample of proton-proton collisions collected with the LHCb detector at center-of-mass energies of 7 and 8 Tev, corresponding to an integrated luminosity of 3 ~fb1^{-1}. For the first time R(D){\cal{R}}(D^{*-}) is determined using the τ\tau lepton decays with three charged pions in the final state. The B0Dτ+ντB^0 \to D^{*-} \tau^+\nu_{\tau} yield is normalized to that of the B0Dπ+ππ+B^0\to D^{*-} \pi^+\pi^-\pi^+ mode, providing a measurement of B(B0Dτ+ντ)/B(B0Dπ+ππ+)=1.97±0.13±0.18{\cal{B}}(B^0\to D^{*-}\tau^+\nu_{\tau})/{\cal{B}}(B^0\to D^{*-}\pi^+\pi^-\pi^+) = 1.97 \pm 0.13 \pm 0.18, where the first uncertainty is statistical and the second systematic. The value of B(B0Dτ+ντ)=(1.42±0.094±0.129±0.054)%{\cal{B}}(B^0 \to D^{*-} \tau^+ \nu_{\tau}) = (1.42 \pm 0.094 \pm 0.129 \pm 0.054)\% is obtained, where the third uncertainty is due to the limited knowledge of the branching fraction of the normalization mode. Using the well-measured branching fraction of the B0Dμ+νμB^0 \to D^{*-} \mu^+\nu_{\mu} decay, a value of R(D)=0.291±0.019±0.026±0.013{\cal{R}}(D^{*-}) = 0.291 \pm 0.019 \pm 0.026 \pm 0.013 is established, where the third uncertainty is due to the limited knowledge of the branching fractions of the normalization and B0Dμ+νμB^0\to D^{*-}\mu^+\nu_{\mu} modes. This measurement is in agreement with the Standard Model prediction and with previous results.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2017-017.htm
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