2,561 research outputs found

    Coevolutionary fine-tuning: evidence for genetic tracking between a specialist wasp parasitoid and its aphid host in a dual metapopulation interaction

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    In the interaction between two ecologically-associated species, the population structure of one species may affect the population structure of the other. Here, we examine the population structures of the aphid Metopeurum fuscoviride, a specialist on tansy Tanacetum vulgare, and its specialist primary hymenopterous parasitoid Lysiphlebus hirticornis, both of which are characterized by multivoltine life histories and a classic metapopulation structure. Samples of the aphid host and the parasitoid were collected from eight sites in and around Jena, Germany, where both insect species co-occur, and then were genotyped using suites of polymorphic microsatellite markers. The host aphid was greatly differentiated in terms of its spatial population genetic patterning, while the parasitoid was, in comparison, only moderately differentiated. There was a positive Mantel test correlation between pairwise shared allele distance (DAS) of the host and parasitoid, i.e. if host subpopulation samples were more similar between two particular sites, so were the parasitoid subpopulation samples. We argue that while the differences in the levels of genetic differentiation are due to the differences in the biology of the species, the correlations between host and parasitoid are indicative of dependence of the parasitoid population structure on that of its aphid host. The parasitoid is genetically tracking behind the aphid host, as can be expected in a classic metapopulation structure where host persistence depends on a delay between host and parasitoid colonization of the patch. The results may also have relevance to the Red Queen hypothesis, whereupon in the ‘arms race’ between parasitoid and its host, the latter ‘attempts’ to evolve away from the former

    To Fib or Not to Fib: Misdiagnosis of Atrial Fibrillation on Telemetry Case Presentation and Root Cause Analysis

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    Case presentation, current practices of telemetry management, root cause analysis, goals for improvement, proposed intervention and next steps

    Measurement of Linear Stark Interference in 199Hg

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    We present measurements of Stark interference in the 61S0^1S_0 →\rightarrow 63P1^3P_1 transition in 199^{199}Hg, a process whereby a static electric field EE mixes magnetic dipole and electric quadrupole couplings into an electric dipole transition, leading to EE-linear energy shifts similar to those produced by a permanent atomic electric dipole moment (EDM). The measured interference amplitude, aSIa_{SI} = (aM1+aE2)(a_{M1} + a_{E2}) = (5.8 ±\pm 1.5)×10−9\times 10^{-9} (kV/cm)−1^{-1}, agrees with relativistic, many-body predictions and confirms that earlier central-field estimates are a factor of 10 too large. More importantly, this study validates the capability of the 199^{199}Hg EDM search apparatus to resolve non-trivial, controlled, and sub-nHz Larmor frequency shifts with EDM-like characteristics.Comment: 4 pages, 4 figures, 1 table; revised in response to reviewer comment

    Improved limit on the permanent electric dipole moment of 199Hg

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    We report the results of a new experimental search for a permanent electric dipole moment of 199Hg utilizing a stack of four vapor cells. We find d(199Hg) = (0.49 \pm 1.29_stat \pm 0.76_syst) x 10^{-29} e cm, and interpret this as a new upper bound, |d(199Hg)| < 3.1 x 10^{-29} e cm (95% C.L.). This result improves our previous 199Hg limit by a factor of 7, and can be used to set new constraints on CP violation in physics beyond the standard model.Comment: 4 pages, 4 figures. additional reference, minor edits in response to reviewer comment

    Bounds on Lorentz and CPT Violation from the Earth-Ionosphere Cavity

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    Electromagnetic resonant cavities form the basis of many tests of Lorentz invariance involving photons. The effects of some forms of Lorentz violation scale with cavity size. We investigate possible signals of violations in the naturally occurring resonances formed in the Earth-ionosphere cavity. Comparison with observed resonances places the first terrestrial constraints on coefficients associated with dimension-three Lorentz-violating operators at the level of 10^{-20} GeV.Comment: 8 pages REVTe

    8-HQA adjusts the number and diversity of bacteria in the gut microbiome of Spodoptera littoralis

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    Quinolinic carboxylic acids are known for their metal ion chelating properties in insects, plants and bacteria. The larval stages of the lepidopteran pest, Spodoptera littoralis, produce 8-hydroxyquinoline-2-carboxylic acid (8-HQA) in high concentrations from tryptophan in the diet. At the same time, the larval midgut is known to harbor a bacterial population. The motivation behind the work was to investigate whether 8-HQA is controlling the bacterial community in the gut by regulating the concentration of metal ions. Knocking out the gene for kynurenine 3-monooxygenase (KMO) in the insect using CRISPR/Cas9 eliminated production of 8-HQA and significantly increased bacterial numbers and diversity in the larval midgut. Adding 8-HQA to the diet of knockout larvae caused a dose-dependent reduction of bacterial numbers with minimal effects on diversity. Enterococcus mundtii dominates the community in all treatments, probably due to its highly efficient iron uptake system and production of the colicin, mundticin. Thus host factors and bacterial properties interact to determine patterns of diversity and abundance in the insect midgut

    Starter Motor Sizing For Large Gas Turbine (Single-Shaft) Driven LNG Strings.

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    LecturePg. 7-16The purpose of this paper is to describe how computer simulation was used to size the main starter motors for single shaft gas turbine driven compressor strings used in a large LNG plant. The paper describes how the components of the system were modelled and discusses assumptions used in the calculations. The paper presents the actual computer output plots showing the predicted torque loading on the motor and the contributions of each of the components in the string to this predicted loading. The simulation program was also used to predict the loading of the motor during a full load test at the compressor vendor's facility. A torquemeter was used to measure the output of the motor during the string acceleration. The paper presents the results of the simulation prediction for the test runs and correlates the actual test measurements to the prediction

    MAX-DOAS measurements of formaldehyde in the Po-Valley

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    International audienceno abstract availabl

    Event-by-event mean p_T fluctuations in pp and Pb-Pb collisions measured by the ALICE experiment at the LHC

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    Non-statistical event-by-event fluctuations of the mean transverse momentum of charged particles in pp and Pb-Pb collisions are studied using the ALICE experiment at the LHC. Little collision energy dependence is observed in pp. The data indicate a common scaling behaviour with event multiplicity from pp to semi-central Pb-Pb collisions. In central Pb-Pb, the results deviate from this trend, exhibiting a significant reduction of the fluctuation strength. The results are compared with measurements in Au-Au collisions at lower energies and with Monte Carlo simulations.Comment: 4 pages, 3 figures, proceedings to Quark Matter 2011; only minor changes in the new version (e.g. description of error bars of fig.3 in more detail, ref.5 updated), figures not changed, this is the published versio
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