716 research outputs found

    Voracité comparative de trois coccinelles prédatrices contre le tétranyque rouge du pommier [Acarina : Tetranychidae]

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    La voracité de la coccinelle à sept points, Coccinella septempunctata, de la coccinelle à quatorze points, Propylea quatuordecimpunctata, et de la coccinelle orientale, Harmonia axyridis, [Coleoptera : Coccinellidae] a été évaluée en laboratoire face au tétranyque rouge du pommier, Panonychus ulmi [Acarina : Tetranychidae]. Les trois espèces ont consommé le tétranyque rouge. H. axyridis était significativement plus vorace que les autres espèces et présente le potentiel le plus élevé comme ennemi naturel du tétranyque. Malgré sa grande taille, C. septempunctata possédait une voracité très faible, ce qui confirme son inefficacité comme agent de lutte face aux acariens phytophages.Voracity of the seven-spotted ladybeetle, Coccinella septempunctata, the fourteen-spotted ladybeetle, Propylea quatuordecimpunctata, and the oriental ladybeetle, Harmonia axyridis [Coleoptera : Coccinellidae], was evaluated in laboratory on the European red mite, Panonychus ulmi [Acarina : Tetranychidae]. The three species fed on the European red mite. H. axyridis was significantly more voracious than the other species and has the greater potential as a natural enemy of the mite. Despite its large size, C. septempunctata showed a very low voracity, confirming its inefficacy as a biological control agent against phytophagous mites

    Biogeographic origin of the common green lacewings (Neuroptera, Chrysopidae) of the Azores archipelago, through morphology analysis

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    Due to a great dispersal ability and small size, insects are probably among the first island colonisers. Chrysoperla carnea sensu lato was for long considered the sole member of the Chrysopidae family in the Azores (Portugal) since it has been regarded as a complex of sibling species in Europe and North America. Its separation into different morphotypes is based on a set of pre-determined morphological traits. Their analysis leads to appraise Azorean Chrysopidae origin, comparing insular and mainland populations. Two outside “carnea complex” species, namely the Nearctic C. rufilabris and the Neotropical C. externa, were also examined to validate the method. Data analysis resulted in grouping separately the two out-group species as expected, and clearly joins insular and Palaearctic specimens of C. lucasina. Chrysoperla agilis, although known to be present in the Azores through courtship song analysis, is morphologically similar to the two other Palaearctic species, which confirms the continental Palaearctic origin of the common green lacewings in the Azores. Madeira has probably served as a stepping-stone to the Azorean colonisation

    Evaluation des connaissances paysannes sur la diversité de l'entomofaune du sorgho et de l'arachide au Burkina Faso

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    Une enquête a été menée, de juillet à décembre 1996, dans cinq provinces productrices du sorgho et de l'arachide au Burkina Faso, pour évaluer les connaissances paysannes sur la diversité des insectes nuisibles aux deux cultures et sur leurs ennemis naturels associés. L'enquête a touché 244 personnes de cinq ethnies les plus représentées du pays. Les résultats montrent que les paysans du Burkina Faso ont une connaissance assez détaillée de la plupart des arthropodes nuisibles majeurs du sorgho et de I'arachide. En revanche, ils identifient certains arthropodes prédateurs, mais ils méconnaissent leur utilité dans la lutte contre les ravageurs des cultures. Pour protéger leurs productions, ils privilégient une lutte chimique sans précautions, au risque de s'intoxiquer et de polluer leur environnement. Il est donc nécessaire de les aider à différencier insectes nuisibles et ennemis naturels dans leurs champs, et à préserver ces derniers. (Résumé d'auteur

    Pathogenicity of Beauveria bassiana isolates toward Leptinotarsa decemlineata [Coleoptera : Chrysomelidae], Myzus persicae [Homoptera : Aphididae] and their predator Coleomegilla maculata lengi [Coleoptera : Coccinellidae]

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    L'effet pathogène de dix isolats de Beauveria bassiana de différentes sources et provenances géographiques a été évalué au laboratoire à une concentration de 107 conidies ml-1 sur deux insectes ravageurs, le doryphore de la pomme de terre ( Leptinotarsa decemlineata) et le puceron vert du pêcher ( Myzus persicae), et leur prédateur, la coccinelle maculée ( Coleomegilla maculata lengi). Six isolats ont provoqué une mortalité élevée sur les trois espèces d'insectes. Les quatre autres ont démontré un différent degré de spécificité pour les insectes visés. Les isolats 49, 233 et 210087 se sont avérés les plus intéressants comme agents de lutte biologique parce qu'ils ont démontré une forte virulence pour les insectes nuisibles mais ne causant qu'une faible mortalité pour la coccinelle.Ten isolates of Beauveria bassiana from different sources and geographical sites were evaluated under laboratory conditions at a concentration of 107 conidia ml-1 for their pathogenicity against two insect pests, the Colorado potato beetle (Leptinotarsa decemlineata) and the green peach aphid (Myzus persicae), and their predator, the spotted ladybird beetle (Coleomegilla maculata lengi). Six isolates were highly virulent to all three insect species. Four others showed different degrees of specificity. The isolates 49, 233 and 210087 were the most interesting for their potential development as biological control agents because they were highly virulent for the two insect pests and caused low mortality in the coccinellid

    Mas-related G-protein–coupled receptors inhibit pathological pain in mice

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    An important objective of pain research is to identify novel drug targets for the treatment of pathological persistent pain states, such as inflammatory and neuropathic pain. Mas-related G-protein–coupled receptors (Mrgprs) represent a large family of orphan receptors specifically expressed in small-diameter nociceptive primary sensory neurons. To determine the roles of Mrgprs in persistent pathological pain states, we exploited a mouse line in which a chromosomal locus spanning 12 Mrgpr genes was deleted (KO). Initial studies indicated that these KO mice show prolonged mechanical- and thermal-pain hypersensitivity after hind-paw inflammation compared with wild-type littermates. Here, we show that this mutation also enhances the windup response of dorsal-horn wide dynamic-range neurons, an electrophysiological model for the triggering of central pain sensitization. Deletion of the Mrgpr cluster also blocked the analgesic effect of intrathecally applied bovine adrenal medulla peptide 8–22 (BAM 8–22), an MrgprC11 agonist, on both inflammatory heat hyperalgesia and neuropathic mechanical allodynia. Spinal application of bovine adrenal medulla peptide 8–22 also significantly attenuated windup in wild-type mice, an effect eliminated in KO mice. These data suggest that members of the Mrgpr family, in particular MrgprC11, may constitute an endogenous inhibitory mechanism for regulating persistent pain in mice. Agonists for these receptors may, therefore, represent a class of antihyperalgesics for treating persistent pain with minimal side effects because of the highly specific expression of their targets

    Removing krypton from xenon by cryogenic distillation to the ppq level

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    The XENON1T experiment aims for the direct detection of dark matter in a cryostat filled with 3.3 tons of liquid xenon. In order to achieve the desired sensitivity, the background induced by radioactive decays inside the detector has to be sufficiently low. One major contributor is the β\beta-emitter 85^{85}Kr which is an intrinsic contamination of the xenon. For the XENON1T experiment a concentration of natural krypton in xenon nat\rm{^{nat}}Kr/Xe < 200 ppq (parts per quadrillion, 1 ppq = 1015^{-15} mol/mol) is required. In this work, the design of a novel cryogenic distillation column using the common McCabe-Thiele approach is described. The system demonstrated a krypton reduction factor of 6.4\cdot105^5 with thermodynamic stability at process speeds above 3 kg/h. The resulting concentration of nat\rm{^{nat}}Kr/Xe < 26 ppq is the lowest ever achieved, almost one order of magnitude below the requirements for XENON1T and even sufficient for future dark matter experiments using liquid xenon, such as XENONnT and DARWIN

    Cross section ratio and angular distributions of the reaction p + d -> 3He + eta at 48.8 MeV and 59.8 MeV excess energy

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    We present new data for angular distributions and on the cross section ratio of the p + d -> 3He + eta reaction at excess energies of Q = 48.8 MeV and Q = 59.8 MeV. The data have been obtained at the WASA-at-COSY experiment (Forschungszentrum J\"ulich) using a proton beam and a deuterium pellet target. While the shape of obtained angular distributions show only a slow variation with the energy, the new results indicate a distinct and unexpected total cross section fluctuation between Q = 20 MeV and Q = 60 MeV, which might indicate the variation of the production mechanism within this energy interval.Comment: 9 pages, 9 figure

    Evidence for a New Resonance from Polarized Neutron-Proton Scattering

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    Exclusive and kinematically complete high-statistics measurements of quasifree polarized np\vec{n}p scattering have been performed in the energy region of the narrow resonance structure dd^* with I(JP)=0(3+)I(J^P) = 0(3^+), MM \approx 2380 MeV/c2c^2 and Γ\Gamma \approx 70 MeV observed recently in the double-pionic fusion channels pndπ0π0pn \to d\pi^0\pi^0 and pndπ+πpn \to d\pi^+\pi^-. The experiment was carried out with the WASA detector setup at COSY having a polarized deuteron beam impinged on the hydrogen pellet target and utilizing the quasifree process dpnp+pspectator\vec{d}p \to np + p_{spectator}. That way the npnp analyzing power AyA_y was measured over a large angular range. The obtained AyA_y angular distributions deviate systematically from the current SAID SP07 NN partial-wave solution. Incorporating the new AyA_y data into the SAID analysis produces a pole in the 3D33G3^3D_3 - ^3G_3 waves as expected from the dd^* resonance hypothesis

    Measurement of the pnppπ0πpn \to pp\pi^0\pi^- Reaction in Search for the Recently Observed Resonance Structure in dπ0π0d\pi^0\pi^0 and dπ+πd\pi^+\pi^- systems

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    Exclusive measurements of the quasi-free pnppπ0πpn \to pp\pi^0\pi^- reaction have been performed by means of pdpd collisions at TpT_p = 1.2 GeV using the WASA detector setup at COSY. Total and differential cross sections have been obtained covering the energy region s\sqrt s = (2.35 - 2.46) GeV, which includes the region of the ABC effect and its associated resonance structure. No ABC effect, {\it i.e.} low-mass enhancement is found in the π0π\pi^0\pi^--invariant mass spectrum -- in agreement with the constraint from Bose statistics that the isovector pion pair can not be in relative s-wave. At the upper end of the covered energy region tt-channel processes for Roper, Δ(1600)\Delta(1600) and ΔΔ\Delta\Delta excitations provide a reasonable description of the data, but at low energies the measured cross sections are much larger than predicted by such processes. Adding a resonance amplitude for the resonance at mm=~2.37 GeV with Γ\Gamma =~70 MeV and I(JP)= 0(3+)I(J^P)=~0(3^+) observed recently in pndπ0π0pn \to d\pi^0\pi^0 and pndπ+πpn \to d\pi^+\pi^- reactions leads to an agreement with the data also at low energies
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