11,243 research outputs found

    New records of ichneumon wasps (Hymenoptera, Ichneumonidae) from Malta

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    Recently some Maltese Hymenoptera were donated to the Hungarian Natural History Museum (HNHM) and some other material was sent to the Natural History Museum in London (BMNH) for identification by the second author. Amongst these specimens were six ichneumon wasp species new to the fauna of Malta. Ichneumonidae taxonomy and nomenclature follow Yu et al. (2012), and host records were traced through this resource. Identifications were based on keys provided by SzĂ©pligeti (1905), Schmiedeknecht (1909), BajĂĄri (1960), Townes et al. (1965), BajĂĄri & MĂłczĂĄr (1969), Townes (1969; 1970a; 1970b; 1971), Horstmann (1976), Gauld & Mitchell (1977), Fitton et al. (1988), Wahl (1993), and Tolkanitz (2007). The voucher specimens are deposited in the Hymenoptera Collection of HNHM, Budapest, Hungary (those indicated by a HNHM id. number below), and some duplicate specimens in D. Mifsud’s private insect collection (CDM) in Malta.peer-reviewe

    Charmonium Suppression by Comover Scattering in Pb+Pb Collisions

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    The first reports of ψ\psi and ψâ€Č\psi' production from experiment NA50 at the CERN SPS are compared to predictions based on a hadronic model of charmonium suppression. Data on centrality dependence and total cross sections are in good accord with these predictions.Comment: 9 pages, latex, 6 figures, epsf, figure added and text modified to clarify result

    Atomic hydrogen cleaning of GaSb(001) surfaces

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    We show that the (001) surface of GaSb can be cleaned efficiently by exposure to atomic hydrogen at substrate temperatures in the range 400–470 °C. This treatment removes carbon and oxygen contamination, leaving a clean, ordered surface with a symmetric (1 × 3) reconstruction after a total H2 dose of approximately 150 kL. An ordered but partially oxidized surface is generated during cleaning, and the removal of this residual oxide is the most difficult part of the process. Auger electron spectroscopy and low energy electron diffraction were used to monitor the chemical cleanliness and the ordering of the surface during the cleaning process, whereas high resolution electron energy loss spectroscopy was used to probe the electronic structure in the near-surface region. The results obtained indicates that this cleaning procedure leaves no residual electronic damage in the near-surface region of the Te-doped (n ~ 5 × 1017 cm – 3) samples of GaSb(001) studied

    Discovering baryon-number violating neutralino decays at the LHC.

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    Recently there has been much interest in the use of single-jet mass and jet substructure to identify boosted particles decaying hadronically at the LHC. We develop these ideas to address the challenging case of a neutralino decaying to three quarks in models with baryonic violation of R parity. These decays have previously been found to be swamped by QCD backgrounds. We demonstrate for the first time that such a decay might be observed directly at the LHC with high significance, by exploiting characteristics of the scales at which its composite jet breaks up into subjets

    Epitaxial growth and surface reconstruction of CrSb(0001)

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    Smooth CrSb(0001) films have been grown by molecular beam epitaxy on MnSb(0001) – GaAs(111) substrates. CrSb(0001) shows (2 × 2), triple domain (1 × 4) and (√3×√3)R30° reconstructed surfaces as well as a (1 × 1) phase. The dependence of reconstruction on substrate temperature and incident fluxes is very similar to MnSb(0001)

    Organopalladium catalyst on S-terminated GaAs(001)-(2×6) surface

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    Organopalladium molecules, such as Pd(CH3COO)2 ({Pd}), immobilized on the S-terminated GaAs(001), termed GaAs–S–{Pd} have high catalytic activity and cycle durability in the Mizoroki–Heck reaction. It is thought that the presence of Ga–S bonds in the single atomic layer S-termination is essential for these catalytic properties despite the much higher thickness (~100 nm) of the {Pd} films. In this study, the authors demonstrate the retention of Ga–S bonds in ultrathin GaAs–S–{Pd} by using reflection high-energy electron diffraction and scanning tunneling microscopy (STM). The ultrathin GaAs–S–{Pd} was prepared by using a vapor-deposition technique. Deposited {Pd} was observed as ~1 nm dotlike structures with STM. The adsorption rate of {Pd} was also investigated

    Habitual accountability routines in the boardroom: How boards balance control and collaboration

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    open3siCorporate accountability is a complex chain of reporting that reaches from external stakeholders into the organization’s management structure. The transition from external to internal accountability mechanisms primarily occurs at the board of directors. Yet outside of incentive mechanisms, we know surprisingly little about how internal actors (management) are held to account by the representatives of external shareholders (the board). This paper explores the process of accountability at this transition point by documenting the routines used by boards to hold the firm’s management to account. In so doing we develop our understanding of the important transition between internal and external firm accountability.embargoed_20190401Nicholson, Gavin; Pugliese, Amedeo; Bezemer, Pieter JanNicholson, Gavin; Pugliese, Amedeo; Bezemer, Pieter Ja

    A perceived gap between invasive species research and stakeholder priorities

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    Information from research has an important role to play in shaping policy and management responses to biological invasions but concern has been raised that research focuses more on furthering knowledge than on delivering practical solutions. We collated 449 priority areas for science and management from 160 stakeholders including practitioners, researchers and policy makers or advisors working with invasive species, and then compared them to the topics of 789 papers published in eight journals over the same time period (2009–2010). Whilst research papers addressed most of the priority areas identified by stakeholders, there was a difference in geographic and biological scales between the two, with individual studies addressing multiple priority areas but focusing on specific species and locations. We hypothesise that this difference in focal scales, combined with a lack of literature relating directly to management, contributes to the perception that invasive species research is not sufficiently geared towards delivering practical solutions. By emphasising the practical applications of applied research, and ensuring that pure research is translated or synthesised so that the implications are better understood, both the management of invasive species and the theoretical science of invasion biology can be enhanced

    Taylor-type rules and total factor productivity

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    This paper examines the impact of a persistent shock to the growth rate of total factor productivity in a New Keynesian model in which the central bank does not observe the shock. The authors then investigate the performance of alternative policy rules in such an incomplete information environment. While some rules perform better than others, the authors demonstrate that inflation is more stable after a persistent productivity shock when monetary policy targets the output growth rate (not the output gap) or the price-level path (not the inflation rate). Both the output growth and price-level path rules generate less volatility in output and inflation following a persistent productivity shock compared with the Taylor rule.Taylor's rule ; Productivity ; Industrial productivity

    Exact approximation of Rao-Blackwellised particle filters

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    Particle methods are a category of Monte Carlo algorithms that have become popular for performing inference in non-linear non-Gaussian state-space models. The class of 'Rao-Blackwellised' particle filters exploits the analytic marginalisation that is possible for some state- space models to reduce the variance of the Monte Carlo estimates. Despite being applicable to only a restricted class of state-space models, such as conditionally linear Gaussian models, these algorithms have found numerous applications. In scenarios where no such analytical integration is possible, it has recently been proposed in Chen et al. [2011] to use 'local' particle filters to carry out this integration numerically. We propose here an alternative approach also relying on \local" particle filters which is more broadly applicable and has attractive theoretical properties. Proof-of-concept simulation results are presented
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