290 research outputs found

    Hymenopterous parasites associated with Phyllonorycter blancardella [Lepidoptera: Gracillariidae] in Nova Scotia and Quebec

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    Une étude a été effectuée dans des vergers commerciaux et non-traités du Québec et de la Nouvelle-Écosse pour déterminer l’abondance et la diversité des parasites de la mineuse marbrée, Phyllonorycter blancardella [Lepidoptera : Gracillariidae]. Au Québec, 29 espèces de parasites ont été retrouvées et elles appartenaient à 7 familles, soit Aphelinidae, Braconidae, Chalcidae, Eulophidae, Ichneumonidae, Pteromalidae et Scelionidae. Les espèces les plus fréquentes étaient : Pholetesor ornigis (67 %), Sympiesis marylandensis (11 %), S. serviceicornis (7 %), Pnigalio maculipes (1,5 %), Tetrasticus spp. (1,2 %). Toutes les autres espèces représentaient moins de 1 % des espèces trouvées. Pholetesor pedias, une espèce braconide relâchée à Frelighsburg, Québec en 1983 n’a pas été détectée en 1984 et 1985. En Nouvelle-Écosse, 19 espèces ont été trouvées et elles appartenaient à 5 familles, soit Braconidae, Chalcidae, Eulophidae, Ichneumonidae et Pteromalidae. Les espèces les plus fréquentes étaient : Pholetesor ornigis (52 %), Pnigalio maculipes (14 %), Sympiesis serviceicornis (12 %), S. marylandensis (9,5 %), Sympiesis spp. (5 %), Horismenus fraternus (1,8 %), Paraleurocerus sp. (1,3 %), Stictopisthus flaviceps (1,1 %); toutes les autres espèces représentaient moins de 1 % des espèces trouvées. Sept et cinq espèces d’hyperparasites ont été retrouvées en Nouvelle-Écosse et au Québec, respectivement. Sticopisthus bilineatus, S. flaviceps, Euderis sp., Pnigalio epilobii, P. pallipes and Paraleurocerus bicoloripes constituent des nouvelles mentions comme parasites de la mineuse marbrée pour l’Amérique du Nord.Mined leaves were collected in commercial and unsprayed (no insecticides) apple orchards of Quebec and Nova Scotia to determine the relative abundance and diversity of parasites of the spotted tentiform leafminer, Phyllonorycter blancardella [Lepidoptera: Gracillariidae]. In Quebec, 29 species of leafminer parasites were recovered, belonging to 7 families: Aphelinidae, Braconidae, Chalcidae, Eulophidae, Ichneumonidae, Pteromalidae and Scelionidae. The most prevalent species were Pholetesor ornigis (67%), Sympiesis marylandensis (11%), S. serviceicornis (7%), Pnigalio maculipes (1.5%), Tetrasticus spp. (1.2%), while all other species accounted for < 1.0%. Pholetesor pedias, a braconid released in 1983 at Frelighsburg, Quebec, was not found in the 1984 and 1985 surveys. In Nova Scotia, 19 parasite species were recovered, belonging to 5 families : Braconidae, Encyrtidae, Eulophidae, Ichneumonidae and Pteromalidae. The most prevalent species were: Pholetesor ornigis (52%), Pnigalio maculipes (14%), Sympiesis serviceicornis (12%), S. marylandensis (9.5%), Sympiesis spp. (5%), Horismenus fraternus (1.8%), Paraleurocerus sp. (1.3%), Stictopisthus flaviceps (1.1%), while all other species accounted for < 1%. Seven and five species of hyperparasites were recovered in Nova Scotia and Quebec, respectively. New records for North America for the spotted tentiform leafminer as a host are : Sticopisthus bilineatus, S. flaviceps, Euderis sp., Pnigalio epilobii, P. pallipes and Paraleurocerus bicoloripes

    Non-standard Hamiltonian effects on neutrino oscillations

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    We investigate non-standard Hamiltonian effects on neutrino oscillations, which are effective additional contributions to the vacuum or matter Hamiltonian. Since these effects can enter in either flavor or mass basis, we develop an understanding of the difference between these bases representing the underlying theoretical model. In particular, the simplest of these effects are classified as ``pure'' flavor or mass effects, where the appearance of such a ``pure'' effect can be quite plausible as a leading non-standard contribution from theoretical models. Compared to earlier studies investigating particular effects, we aim for a top-down classification of a possible ``new physics'' signature at future long-baseline neutrino oscillation precision experiments. We develop a general framework for such effects with two neutrino flavors and discuss the extension to three neutrino flavors, as well as we demonstrate the challenges for a neutrino factory to distinguish the theoretical origin of these effects with a numerical example. We find how the precision measurement of neutrino oscillation parameters can be altered by non-standard effects alone (not including non-standard interactions in the creation and detection processes) and that the non-standard effects on Hamiltonian level can be distinguished from other non-standard effects (such as neutrino decoherence and decay) if we consider specific imprint of the effects on the energy spectra of several different oscillation channels at a neutrino factory.Comment: 30 pages, 6 figures, LaTeX, final version, published in Eur.Phys.J.

    ICZM and WTP of stakeholders for beach conservation: Policymaking suggestions from an Italian case study

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    In accordance with integrated coastal zone management (ICZM), private stakeholders could be asked to pay for the benefits from beach conservation projects. Since a private contribution is measured by the amount of other goods a person is willing to give up for beach quality, it can be solicited in monetary terms or, when possible, in other forms, such as specific works. In this paper, by analysing the results of two surveys in Italy concerning stakeholders' perceptions of ICZM and their willingness to pay for these benefits, suggestions for beach management are provided to policymakers. One survey focuses on beach visitors who are asked to pay in monetary terms, while the other focuses on sunbathing establishment managers, who are asked to pay not only in monetary terms but also through beach works. The results show that the majority of these stakeholders are fully or partially aware of what ICZM is, and are unwilling to pay. However, regression analysis of those willing to pay suggests that promoting an information and education campaign about ICZM may be important if stakeholders' probability of paying is to be increased

    The Muonium Atom as a Probe of Physics beyond the Standard Model

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    The observed interactions between particles are not fully explained in the successful theoretical description of the standard model to date. Due to the close confinement of the bound state muonium (M=μ+eM = \mu^+ e^-) can be used as an ideal probe of quantum electrodynamics and weak interaction and also for a search for additional interactions between leptons. Of special interest is the lepton number violating process of sponteanous conversion of muonium to antimuonium.Comment: 15 pages,6 figure

    Prevalence and relevance of abnormal glucose metabolism in acute coronary syndromes : insights from the PLATelet inhibition and patient outcomes (PLATO) trial

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    Diabetes mellitus (DM) and abnormal glucose metabolism are associated with cardiovascular (CV) disease. We investigated the prevalence and prognostic importance of dysglycaemia in patients with acute coronary syndromes (ACS) in the PLATelet inhibition and patient Outcomes (PLATO) trial. Diabetes was defined as known diabetes or HbA1c ≥ 6.5% or non-fasting glucose ≥ 11.1 mmol/L on admission, prediabetes as HbA1c ≥ 5.7% but < 6.5%, and no diabetes as HbA1c < 5.7%. The primary endpoint was the composite of CV death, spontaneous myocardial infarction type 1 (sMI) or stroke at 12 months. Multivariable Cox regression models, adjusting for baseline characteristics, and biomarkers NT-proBNP and troponin I, were used to explore the association between glycaemia and outcome. On admission, 16,007 (86.1%) patients had HbA1c and/or glucose levels available and were subdivided into DM 38.5% (6160) (1501 patients had no previous DM diagnosis), prediabetes 38.8% (6210), and no DM 22.7% (3637). Kaplan Meier event rates at 12 months for CV death, sMI or stroke per subgroups were 14.5% (832), 9.0% (522), and 8.5% (293), respectively with multivariable adjusted HRs, versus no diabetes, for diabetes: 1.71 (1.50–1.95) and for prediabetes 1.03 (0.90–1.19). Corresponding event rates for CV death were 6.9% (391), 3.4% (195) and 3.0% (102), respectively, with adjusted HRs for patients with DM of: 1.92 (1.42–2.60) and for prediabetes 1.02 (0.79–1.32). Abnormal glucose metabolism is common in ACS patients, but only patients with definite DM have an increased CV risk, indicating that prediabetes is not immediately associated with worse CV outcomes

    Theory of Two-Dimensional Quantum Heisenberg Antiferromagnets with a Nearly Critical Ground State

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    We present the general theory of clean, two-dimensional, quantum Heisenberg antiferromagnets which are close to the zero-temperature quantum transition between ground states with and without long-range N\'{e}el order. For N\'{e}el-ordered states, `nearly-critical' means that the ground state spin-stiffness, ρs\rho_s, satisfies ρsJ\rho_s \ll J, where JJ is the nearest-neighbor exchange constant, while `nearly-critical' quantum-disordered ground states have a energy-gap, Δ\Delta, towards excitations with spin-1, which satisfies ΔJ\Delta \ll J. Under these circumstances, we show that the wavevector/frequency-dependent uniform and staggered spin susceptibilities, and the specific heat, are completely universal functions of just three thermodynamic parameters. Explicit results for the universal scaling functions are obtained by a 1/N1/N expansion on the O(N)O(N) quantum non-linear sigma model, and by Monte Carlo simulations. These calculations lead to a variety of testable predictions for neutron scattering, NMR, and magnetization measurements. Our results are in good agreement with a number of numerical simulations and experiments on undoped and lightly-doped La2δSrδCuO4La_{2-\delta} Sr_{\delta}Cu O_4.Comment: 81 pages, REVTEX 3.0, smaller updated version, YCTP-xxx

    Towards Machine Wald

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    The past century has seen a steady increase in the need of estimating and predicting complex systems and making (possibly critical) decisions with limited information. Although computers have made possible the numerical evaluation of sophisticated statistical models, these models are still designed \emph{by humans} because there is currently no known recipe or algorithm for dividing the design of a statistical model into a sequence of arithmetic operations. Indeed enabling computers to \emph{think} as \emph{humans} have the ability to do when faced with uncertainty is challenging in several major ways: (1) Finding optimal statistical models remains to be formulated as a well posed problem when information on the system of interest is incomplete and comes in the form of a complex combination of sample data, partial knowledge of constitutive relations and a limited description of the distribution of input random variables. (2) The space of admissible scenarios along with the space of relevant information, assumptions, and/or beliefs, tend to be infinite dimensional, whereas calculus on a computer is necessarily discrete and finite. With this purpose, this paper explores the foundations of a rigorous framework for the scientific computation of optimal statistical estimators/models and reviews their connections with Decision Theory, Machine Learning, Bayesian Inference, Stochastic Optimization, Robust Optimization, Optimal Uncertainty Quantification and Information Based Complexity.Comment: 37 page

    Measurement of the Charged Multiplicities in b, c and Light Quark Events from Z0 Decays

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    Average charged multiplicities have been measured separately in bb, cc and light quark (u,d,su,d,s) events from Z0Z^0 decays measured in the SLD experiment. Impact parameters of charged tracks were used to select enriched samples of bb and light quark events, and reconstructed charmed mesons were used to select cc quark events. We measured the charged multiplicities: nˉuds=20.21±0.10(stat.)±0.22(syst.)\bar{n}_{uds} = 20.21 \pm 0.10 (\rm{stat.})\pm 0.22(\rm{syst.}), nˉc=21.28±0.46(stat.)0.36+0.41(syst.)\bar{n}_{c} = 21.28 \pm 0.46(\rm{stat.}) ^{+0.41}_{-0.36}(\rm{syst.}) nˉb=23.14±0.10(stat.)0.37+0.38(syst.)\bar{n}_{b} = 23.14 \pm 0.10(\rm{stat.}) ^{+0.38}_{-0.37}(\rm{syst.}), from which we derived the differences between the total average charged multiplicities of cc or bb quark events and light quark events: Δnˉc=1.07±0.47(stat.)0.30+0.36(syst.)\Delta \bar{n}_c = 1.07 \pm 0.47(\rm{stat.})^{+0.36}_{-0.30}(\rm{syst.}) and Δnˉb=2.93±0.14(stat.)0.29+0.30(syst.)\Delta \bar{n}_b = 2.93 \pm 0.14(\rm{stat.})^{+0.30}_{-0.29}(\rm{syst.}). We compared these measurements with those at lower center-of-mass energies and with perturbative QCD predictions. These combined results are in agreement with the QCD expectations and disfavor the hypothesis of flavor-independent fragmentation.Comment: 19 pages LaTex, 4 EPS figures, to appear in Physics Letters

    Gravitational Radiation From Cosmological Turbulence

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    An injection of energy into the early Universe on a given characteristic length scale will result in turbulent motions of the primordial plasma. We calculate the stochastic background of gravitational radiation arising from a period of cosmological turbulence, using a simple model of isotropic Kolmogoroff turbulence produced in a cosmological phase transition. We also derive the gravitational radiation generated by magnetic fields arising from a dynamo operating during the period of turbulence. The resulting gravitational radiation background has a maximum amplitude comparable to the radiation background from the collision of bubbles in a first-order phase transition, but at a lower frequency, while the radiation from the induced magnetic fields is always subdominant to that from the turbulence itself. We briefly discuss the detectability of such a signal.Comment: 20 pages. Corrections for an errant factor of 2 in all the gravity wave characteristic amplitudes. Accepted for publication in Phys. Rev.
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