12,982 research outputs found

    The Bindweed Plume Moth, \u3ci\u3eEmmelina Monodactyla\u3c/i\u3e (Lepidoptera: Pterophoridae): First Host Record for \u3ci\u3ePhaeogenes Vincibilis\u3c/i\u3e (Hymenoptera: Ichneumonidae)

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    The first host record for Phaeogenes (= Oronotus) vincibilis, a solitary ichneumonine pupal parasite, is the bindweed plume moth, Emmelina monodactyla

    Management factors affecting the use of pasture by table chickens in extensive production systems

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    Whether chickens will make proper use of pasture is a problem experienced by producers of free-range and organic chickens. The aims of this project are to identify husbandry techniques and aspects of system design that encourage good pasture use. Two studies have been conducted comprising a winter and a summer flock. The aim of the winter flock was to examine the effect of outdoor artificial shelter on pasture usage. This was done for female Ross 308 birds grown to day 56, and ISA 657 birds grown to day 81. In summer, ISA 657 birds were grown to day 81. Treatments were either standard or enriched brooding, with pasture only or enriched pasture. Standard brooding was in a controlled environment house until day 42. Enriched brooding was in naturally ventilated houses in which birds had sight of pasture from an early age and access from day 21. Enriched pasture included artificial shelter, with straw bales and a conifer “wigwam” used to provide natural shelter. Chickens may be encouraged to go outdoors by brooding in a less “controlled” environment than that used for intensive broilers, and by allowing access to pasture when young. However, mortality was higher. Conifer wigwams may offer a means for more even use of pasture and better distribution of droppings

    Formation of the Galactic globular clusters with He-rich stars in low-mass halos virialized at high redshift

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    Recent observations have reported that the Galactic globular clusters (GCs) with unusually extended horizontal-branch (EHB) morphologies show a significantly lower velocity dispersion compared with that of the entire Galactic GC system. We consider that the observed distinctive kinematics of GCs with EHB has valuable information on the formation epochs of GCs and accordingly discuss this observational result based on cosmological N-body simulations with a model of GC formation. We assume that GCs in galaxies were initially formed in low-mass halos at high redshifts and we investigate final kinematics of GCs in their host halos at z=0z=0. We find that GCs formed in halos virialized at z>10 show lower velocity dispersions on average than those formed at z>6 for halos with GCs at z=0. We thus suggest that the origin of the observed lower velocity dispersion for the Galactic GCs with EHBs is closely associated with earlier formation epochs (z>10) of halos initially hosting the GCs in the course of the Galaxy formation. Considering that the origin of EHBs can be due to the presence of helium-enhanced second-generation stars in GCs, we discuss the longstanding second parameter problem of GCs in the context of different degrees of chemical pollution in GC-forming gas clouds within low-mass halos virialized at different redshifts.Comment: 5 pages, 3 figures, accepted by MNRAS Letter

    Homeownership and Unemployment: The Roles of Leverage and Public Housing

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    Oswald hypothesizes that regions and countries with high homeownership rates will experience higher natural rates of unemployment and that rising homeownership in OECD countries since the 1960s provides a key explanation for the rise in the natural rate of unemployment over the same time period. Recent tests of the Oswald thesis have found the opposite. This study differs from earlier ones both by considering different states of ownership (degrees of leverage) and types of tenancy (private, public, and rent-free) and by examining data from Australia, rather than the U.S. We demonstrate that the recent anti-Oswald results are the result of (1) highly leveraged owners having a greater incentive to remain employed and to become reemployed more rapidly that outright owners and (2) those paying below-market rents having a lower incentive to avoid unemployment or become reemployed than those paying market rents. The only positive Oswald result is that females who are outright owners have significantly slower exits from unemployment. Overall, homeownership does not increase unemployment. Finally, in line with expectations but in contrast to some earlier studies, our results indicate a significant impact of the predicted replacement ratio (unemployment benefits to wage if reemployed) on unemployment behavior. Persons with a higher predicted ratio are significantly more likely to become unemployed, and unemployed females with a higher predicted replacement ratio have longer unemployment spells than those with lower predicted ratios.

    Illustrating field emission theory by using Lauritsen plots of transmission probability and barrier strength

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    This technical note relates to the theory of cold field electron emission (CFE). It starts by suggesting that, to emphasize common properties in relation to CFE theory, the term 'Lauritsen plot' could be used to describe all graphical plots made with the reciprocal of barrier field (or the reciprocal of a quantity proportional to barrier field) on the horizontal axis. It then argues that Lauritsen plots related to barrier strength (G) and transmission probability (D) could play a useful role in discussion of CFE theory. Such plots would supplement conventional Fowler-Nordheim (FN) plots. All these plots would be regarded as particular types of Lauritsen plot. The Lauritsen plots of -G and lnD can be used to illustrate how basic aspects of FN tunnelling theory are influenced by the mathematical form of the tunnelling barrier. These, in turn, influence local emission current density and emission current. Illustrative applications used in this note relate to the well-known exact triangular and Schottky-Nordheim barriers, and to the Coulomb barrier (i.e., the electrostatic component of the electron potential energy barrier outside a model spherical emitter). For the Coulomb barrier, a good analytical series approximation has been found for the barrier-form correction factor; this can be used to predict the existence (and to some extent the properties) of related curvature in FN plots.Comment: Based on a poster presented at the 25th International Vacuum Nanoelectronics Conference, Jeju, S. Korea, July 2012. Version 3 incorporates small changes made at proof stag

    An application of design knowledge captured from multiple sources

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    The Hubble Space Telescope Operational Readiness Expert Safemode Investigation System (HSTORESIS) is a reusable knowledge base shell used to demonstrate the integration and application of design knowledge captured from multiple technical domains. The design of HSTORESIS is based on a partitioning of knowledge to maximize the potential for reuse of certain types of knowledge

    Mirror Map as Generating Function of Intersection Numbers: Toric Manifolds with Two K\"ahler Forms

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    In this paper, we extend our geometrical derivation of expansion coefficients of mirror maps by localization computation to the case of toric manifolds with two K\"ahler forms. Especially, we take Hirzebruch surfaces F_{0}, F_{3} and Calabi-Yau hypersurface in weighted projective space P(1,1,2,2,2) as examples. We expect that our results can be easily generalized to arbitrary toric manifold.Comment: 45 pages, 2 figures, minor errors are corrected, English is refined. Section 1 and Section 2 are enlarged. Especially in Section 2, confusion between the notion of resolution and the notion of compactification is resolved. Computation under non-zero equivariant parameters are added in Section
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