8,258 research outputs found

    Negative impacts of felling in exotic spruce plantations on moth diversity mitigated by remnants of deciduous tree cover

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    Moths are a vital ecosystem component and are currently undergoing extensive and severe declines across multiple species, partly attributed to habitat alteration. Although most remaining forest cover in Europe consists of intensively managed plantation woodlands, no studies have examined the influence of management practices on moth communities within plantations. Here, we aimed to determine: (1) how species richness, abundance, diversity of macro and micro moths in commercial conifer plantations respond to management at multiple spatial scales; (2) what the impacts of forest management practices on moth diversity are, and (3) how priority Biodiversity Action Plan (BAP) species respond to management. BAP species were selected as they represent formerly widespread and common species, which have undergone substantial declines in the UK and Europe. We assessed moth communities in three conifer plantations in Northern England and Scotland by light trapping, combining local (e.g. age of planting) and landscape level (e.g. proximity to felled areas) characteristics to evaluate the impacts of forest management on moths. We found no relationship between local factors and moth richness, abundance and diversity but the amount of clear felling in the surrounding landscape had a strongly negative correlation. In contrast, the amount and proximity of broadleaf cover in the surrounding landscape positively influenced macro moth richness and abundance. For six BAP species, abundances were lower close to felled areas but increased with the size of adjacent broadleaf patches. We conclude that clear felling negatively affects moths, probably through alteration of habitats, the loss of larval host plants, and by limiting dispersal. A shift to continuous cover and maintaining broadleaf tree cover within plantations will greatly enhance their value for moth communities

    Low-Temperature Long-Time Simulations of Ising Ferromagnets using the Monte Carlo with Absorbing Markov Chains method

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    The Monte Carlo with Absorbing Markov Chains (MCAMC) method is introduced. This method is a generalization of the rejection-free method known as the nn-fold way. The MCAMC algorithm is applied to the study of the very low-temperature properties of the lifetime of the metastable state of Ising ferromagnets. This is done both for square-lattice and cubic-lattice nearest-neighbor models. Comparison is made with exact low-temperature predictions, in particular the low-temperature predictions that the metastable lifetime is discontinuous at particular values of the field. This discontinuity for the square lattice is not seen in finite-temperatures studies. For the cubic lattice, it is shown that these `exact predictions' are incorrect near the fields where there are discontinuities. The low-temperature formula must be modified and the corrected low-temperature predictions are not discontinuous in the energy of the nucleating droplet.Comment: Submitted to Computer Physics Communicatinos, for proceedings of the Conference CCP2001, 4 figure

    Update on B→D∗ℓνB\to D^\ast \ell \nu form factor at zero-recoil using the Oktay-Kronfeld action

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    We present an update on the calculation of Bˉ→D∗ℓνˉ\bar{B}\to D^\ast \ell \bar{\nu} semileptonic form factor at zero recoil using the Oktay-Kronfeld bottom and charm quarks on Nf=2+1+1N_f=2+1+1 flavor HISQ ensembles generated by the MILC collaboration. Preliminary results are given for two ensembles with a≈0.12a\approx 0.12 and 0.090.09 fm and Mπ≈310M_\pi\approx 310 MeV. Calculations have been done with a number of valence quark masses, and the dependence of the form factor on them is investigated on the a≈0.12a\approx 0.12 fm ensemble. The excited state is controlled by using multistate fits to the three-point correlators measured at 4--6 source-sink separations.Comment: 7 pages and 4 figures. Talk at The 36th Annual International Symposium on Lattice Field Theory - LATTICE201
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