17 research outputs found

    Brown-Tail Moth, \u3ci\u3eEuproctis Chrysorrhoea,\u3c/i\u3e an Indigenous Pest of Parks and Public in the Benelux Countries (Lepidoptera: Lymantriidae)

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    Euproctis chrysorrhoea is a pest of park and shade trees and of the public in the Benelux countries as well as in the northeastern United States and Canada. In the Benelux countries the brown-tail moth is present every year in the dune regions, where it mainly feeds on Hippophae rhamnoides. Hairs from the larvae are irritating to the human skin producing a papular urticaria. An outbreak of the caterpillars produced widespread discomfort at a beach in the Netherlands in 1982 following defoliation of food plants and migration of the larvae seeking food, with resulting human contact, as well as wind dispersal of the hairs

    New calculations of the PNC Matrix Element for the JπTJ^{\pi}T 0+1,0−1^{+}1,0^{-}1 doublet in 14^{14}N

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    A new calculation of the predominantly isoscalar PNC matrix element between the JπTJ^{\pi}T 0+1,0−10^{+}1,0^{-}1 (Ex≈_{x} \approx 8.7 MeV) states in 14^{14}N has been carried out in a (0+1+2+3+4)ℏω\hbar \omega model space with the Warburton-Brown interaction. The magnitude of the PNC matrix element of 0.22 to 0.34 eV obtained with the DDH PNC interaction is substantially suppressed compared with previous calculations in smaller model spaces but shows agreement with the preliminary Seattle experimental data. The calculated sign is opposite to that obtained experimentally, and the implications of this are discussed.Comment: REVTEX, 28 page

    Parity Mixed Doublets in A = 36 Nuclei

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    The Îł\gamma-circular polarizations (PÎłP_{\gamma}) and asymmetries (AÎłA_{\gamma}) of the parity forbidden M1 + E2 Îł\gamma-decays: 36Cl∗(Jπ=2−;T=1;Ex=1.95^{36}Cl^{\ast} (J^{\pi} = 2^{-}; T = 1; E_{x} = 1.95 MeV) →\rightarrow 36Cl(Jπ=2+;T=1;g.s.)^{36}Cl (J^{\pi} = 2^{+}; T = 1; g.s.) and 36Ar∗(Jπ=2−;T=0;Ex=4.97^{36}Ar^{\ast} (J^{\pi} = 2^{-}; T = 0; E_{x} = 4.97 MeV) →\rightarrow 36Ar∗(Jπ=2+;T=0;Ex=1.97^{36}Ar^{\ast} (J^{\pi} = 2^{+}; T = 0; E_{x} = 1.97 MeV) are investigated theoretically. We use the recently proposed Warburton-Becker-Brown shell-model interaction. For the weak forces we discuss comparatively different weak interaction models based on different assumptions for evaluating the weak meson-hadron coupling constants. The results determine a range of PÎłP_{\gamma} values from which we find the most probable values: PÎłP_{\gamma} = 1.1⋅10−41.1 \cdot 10^{-4} for 36Cl^{36}Cl and PÎłP_{\gamma} = 3.5⋅10−43.5 \cdot 10^{-4} for 36Ar^{36}Ar.Comment: RevTeX, 17 pages; to appear in Phys. Rev.

    Bioclastic bottom‐current deposits of a Devonian contourite terrace: Facies variability and depositional architecture (Tafilalt Platform, Morocco)

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    ABSTRACTThe study examines bioclastic carbonate contourites that arise from the broad spectrum of bottom‐current related sedimentary processes ranging from deposition to erosion. The result of the intermittent accumulation of sediment are thin and condensed successions with abundant hiatuses. Such bottom‐current deposits are poorly known, since the broadly accepted contourite‐facies model, the bi‐gradational sequence, characterizes environments of contourite depositional systems as a continuous accretion of fine‐grained siliciclastic sediments. To increase current understanding of the carbonate facies within hiatal contourite records, the Eifelian–Frasnian of the Tafilalt Platform in Morocco was investigated. The succession is divided into five facies associations that are interpreted to reflect pelagic sedimentation and deposition from bottom currents on a contourite terrace, a gently inclined section of the upper slope of Gondwana shaped by a water‐mass interface. Contourite deposition was mainly controlled by oxic clear‐water currents (documented by moderately to completely bioturbated limestones with abundant hydrogenetic ferromanganese nodules, and low organic‐carbon contents), at times also by an anoxic water mass (featured by organic‐rich coquinas with absent to sparse bioturbation and predominantly syngenetic framboidal pyrites). Biostratigraphic data and the overall depositional architecture display palaeoceanographic hydrodynamic processes associated with a shifting water‐mass interface. The inner terrace was characterized by an alongslope contourite channel and a small mounded drift at its downslope margin. Energetic bottom currents furthermore caused abraded surfaces, i.e. plain areas of non‐deposition and localized erosion, and sandy condensation layers. The microfacies reflects repeated alternation between suspension deposition, winnowing of fines, bedload traction, dynamic sediment bypassing and reworking, together with concomitant seafloor cementation. Coquinas of mainly planktonic and nektonic organisms are identified as integral parts of bi‐gradational contourite sequences showing inverse and normal grading. Hiatal lag concentrations of carbonate intraclasts, ferromanganese nodules and conodonts often drape hardgrounds and erosional surfaces at the midpoint of these frequently incomplete sequences. This Devonian case provides the opportunity to investigate the spatial and temporal variability of the bed‐scale contourite sequence, also with regard to the drift‐scale depositional architecture. In addition, the identified high‐resolution record is a starting point for unravelling the pattern of oceanic circulation in the Devonian greenhouse world.Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/50110000165
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