7,217 research outputs found

    Public access to the countryside: An exploration of the costs and benefits of farmland walking trails

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    To date, estimates of individuals’ willingness to pay (WTP) for access to the countryside have typically been on sites of special interest such as developed walking routes, public rights of way in specific areas, national parks and forests (see Lockwood and Tracy, 1995; Bennett and Tranter, 1997; Crabtree and MacDonald, 1997; Liston-Heyes and Heyes, 1999; Garrod et al., 1998; Bennett et al., 2003; Buckley et al., 2009; Morris et al., 2009). There has been little if any attempt to derive estimates of individuals’ WTP for the provision of walking trails in the wider countryside at a national level. The present study aims to build on previous work by examining the demand for particular types of walking trails through a nationally representative survey of the Irish population. One further advantage of this research is that apart from valuing walking activities in a generic sense this paper investigates what types of investment in facilities associated with walking trails generate the greatest welfare gains. Furthermore, using a nationally representative survey of the farming population this paper examines farmers’ willingness to participate in a hypothetical walking scheme whereby the general public will be allowed access to specific trails. First by way of background this paper will discuss the situation in relation to access rights to the countryside across a number of countries. Second this paper will outline the research approach which is followed with a discussion of the empirical results. Finally this paper will conclude with a discussion of the papers main findings and their implications for the provision of public access to the countryside.This work was funded by the Department of Agriculture, Fisheries and Food under the Stimulus Funding

    Simulation of soil carbon efflux from an arable soil using the ECOSSE model: Need for an improved model evaluation framework?

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    Globally, it is estimated that ~ 1500 Pg C of organic carbon is stored in the top meter of terrestrial soils. This represents the largest terrestrial pool of carbon. Appropriate management of soils, to maintain or increase the soil carbon pool, represents a significant climate change mitigation opportunity. To achieve this, appropriate tools and models are required in order to more accurately estimate soil carbon fluxes with a view to informing and developing more effective land use management strategies. Central to this is the evaluation of models currently in use to estimate soil carbon emissions. In the present study, we evaluate the ECOSSE (Estimating Carbon in Organic Soils – Sequestration and Emissions) model which has its origins in both SUNDIAL and RothC and has been widely used globally to model soil CO2 fluxes across different locations and land-use types on both organic and mineral soils. In contrast to previous studies, the model was found to poorly represent observed soil respiration at the study site, an arable cropland on mineral soil located in south-east Ireland. To isolate potential sources of error, the model was decomposed into its component rate equations or modifiers. This investigation highlighted a deficiency in the model simulated soil water, resulting in significant inhibition of the model simulated CO2 flux relative to the observed data. When measured values of soil water at the site were employed, the model simulated soil respiration improved significantly (r2 of 0.775 vs 0.154). This highlighted model deficiency remains to be evaluated at other sites; however, the research highlights the need for a more comprehensive evaluation of soil carbon models prior to their use in informing policy, particularly models which are employed at larger scales and for climate change projections

    Simulation of soil carbon efflux from an arable soil using the ECOSSE model: Need for an improved model evaluation framework?

    Get PDF
    Globally, it is estimated that ~ 1500 Pg C of organic carbon is stored in the top meter of terrestrial soils. This represents the largest terrestrial pool of carbon. Appropriate management of soils, to maintain or increase the soil carbon pool, represents a significant climate change mitigation opportunity. To achieve this, appropriate tools and models are required in order to more accurately estimate soil carbon fluxes with a view to informing and developing more effective land use management strategies. Central to this is the evaluation of models currently in use to estimate soil carbon emissions. In the present study, we evaluate the ECOSSE (Estimating Carbon in Organic Soils – Sequestration and Emissions) model which has its origins in both SUNDIAL and RothC and has been widely used globally to model soil CO2 fluxes across different locations and land-use types on both organic and mineral soils. In contrast to previous studies, the model was found to poorly represent observed soil respiration at the study site, an arable cropland on mineral soil located in south-east Ireland. To isolate potential sources of error, the model was decomposed into its component rate equations or modifiers. This investigation highlighted a deficiency in the model simulated soil water, resulting in significant inhibition of the model simulated CO2 flux relative to the observed data. When measured values of soil water at the site were employed, the model simulated soil respiration improved significantly (r2 of 0.775 vs 0.154). This highlighted model deficiency remains to be evaluated at other sites; however, the research highlights the need for a more comprehensive evaluation of soil carbon models prior to their use in informing policy, particularly models which are employed at larger scales and for climate change projections

    Optimization Of Detergent-Mediated Reconstitution Of Influenza A M2 Protein Into Proteoliposomes

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    We report the optimization of detergent-mediated reconstitution of an integral membrane-bound protein, full-length influenza M2 protein, by direct insertion into detergent-saturated liposomes. Detergent-mediated reconstitution is an important method for preparing proteoliposomes for studying membrane proteins, and must be optimized for each combination of protein and membrane constituents used. The purpose of the reconstitution was to prepare samples for site-directed spin-labeling electron paramagnetic resonance (SDSL-EPR) studies. Our goals in optimizing the protocol were to minimize the amount of detergent used, reduce overall proteoliposome preparation time, and confirm the removal of all detergent. The liposomes were comprised of (1-palmitoyl-2-oleyl-sn-glycero-phosphocholine (POPC) and 1-palmitoyl-2-oleyl-sn-glycero-3-[phospho-rac-(1-glycerol)] (POPG), and the detergent octylglucoside (OG) was used for reconstitution. Rigorous physical characterization was applied to optimize each step of the reconstitution process. We used dynamic light scattering (DLS) to determine the amount of OG needed to saturate the preformed liposomes. During detergent removal by absorption with Bio-Beads, we quantified the detergent concentration by means of a colorimetric assay, thereby determining the number of Bio-Bead additions needed to remove all detergent from the final proteoliposomes. We found that the overnight Bio-Bead incubation used in previously published protocols can be omitted, reducing the time needed for reconstitution. We also monitored the size distribution of the proteoliposomes with DLS, confirming that the size distribution remains essentially constant throughout the reconstitution process

    Detection of OH absorption against PSR B1849+00

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    We have searched for OH absorption against seven pulsars using the Arecibo telescope. In both OH mainlines (at 1665 and 1667 MHz), deep and narrow absorption features were detected toward PSR B1849+00. In addition, we have detected several absorption and emission features against B33.6+0.1, a nearby supernova remnant (SNR). The most interesting result of this study is that a pencil-sharp absorption sample against the PSR differs greatly from the large-angle absorption sample observed against the SNR. If both the PSR and the SNR probe the same molecular cloud then this finding has important implications for absorption studies of the molecular medium, as it shows that the statistics of absorbing OH depends on the size of the background source. We also show that the OH absorption against the PSR most likely originates from a small (<30 arcsec) and dense (>10^5 cm^-3) molecular clump.Comment: 12 pages, 8 figures. Accepted for publication in Ap

    An Approximate Large NN Method for Lattice Chiral Models

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    An approximation is used that permits one to explicitly solve the two-point Schwinger-Dyson equations of the U(N) lattice chiral models. The approximate solution correctly predicts a phase transition for dimensions dd greater than two. For d2d \le 2 , the system is in a single disordered phase with a mass gap. The method reproduces known N=N=\infty results well for d=1d=1. For d=2d=2, there is a moderate difference with N=N=\infty results only in the intermediate coupling constant region.Comment: Latex file, 19 page

    Early Cenozoic denudation of central west Britain in response to transient and permanent uplift above a mantle plume

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    Upwelling mantle plumes beneath continental crust are predicted to produce difficult to quantify, modest uplift and denudation. The contribution of permanent and transient components to the uplift is also difficult to distinguish. A pulse of denudation in Britain in the Early Paleogene has been linked, although with some controversy, with the arrival of the proto-Iceland mantle plume. In this contribution we show that combining apatite and zircon (U-Th-Sm)/He and apatite fission track analyses from central west Britain with numerical modeling clearly identifies a pulse of early Cenozoic denudation. The data indicate that rock uplift and denudation were centered on the northern East Irish Sea Basin and 1.0–2.4 km of rocks were removed during the latest Cretaceous-early Paleogene. Uplift and erosion appears to have started a few million years before the earliest magmatism in the region. The regional denudation pattern mirrors the distribution of low-density magmatic rocks that has been imaged in the deep crust. However, the injection of the underplating melt is not enough to account for the total denudation. An additional regional uplift of at least 300 m is required, which is consistent with a transient thermal effect from the hot mantle plume. The rapid exhumation event ceased by ~40 Ma and the data do not require significant Neogene exhumation

    World-line Quantisation of a Reciprocally Invariant System

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    We present the world-line quantisation of a system invariant under the symmetries of reciprocal relativity (pseudo-unitary transformations on ``phase space coordinates" (xμ(τ),pμ(τ))(x^\mu(\tau),p^\mu(\tau)) which preserve the Minkowski metric and the symplectic form, and global shifts in these coordinates, together with coordinate dependent transformations of an additional compact phase coordinate, θ(τ)\theta(\tau)). The action is that of free motion over the corresponding Weyl-Heisenberg group. Imposition of the first class constraint, the generator of local time reparametrisations, on physical states enforces identification of the world-line cosmological constant with a fixed value of the quadratic Casimir of the quaplectic symmetry group Q(D1,1)U(D1,1)H(D)Q(D-1,1)\cong U(D-1,1)\ltimes H(D), the semi-direct product of the pseudo-unitary group with the Weyl-Heisenberg group (the central extension of the global translation group, with central extension associated to the phase variable θ(τ)\theta(\tau)). The spacetime spectrum of physical states is identified. Even though for an appropriate range of values the restriction enforced by the cosmological constant projects out negative norm states from the physical spectrum, leaving over spin zero states only, the mass-squared spectrum is continuous over the entire real line and thus includes a tachyonic branch as well

    Investigation of Systematic Bias in Radiometric Diameter Determination of Near-Earth Asteroids: the Night Emission Simulated Thermal Model (NESTM)

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    The Near-Earth Asteroid Thermal Model (NEATM, Harris, 1998) has proven to be a reliable simple thermal model for radiometric diameter determination. However NEATM assumes zero thermal emission on the night side of an asteroid. We investigate how this assumption affects the best-fit beaming parameter, overestimates the effective diameter and underestimates the albedo at large phase angles, by testing NEATM on thermal IR fluxes generated from simulated asteroid surfaces with different thermal inertia. We compare NEATM to radar diameters and find that NEATM overestimates the diameter when the beaming parameter is fitted to multi-wavelength observations and underestimates the diameter when the default beaming parameter is used. The Night Emission Simulated Thermal Model (NESTM) is introduced. NESTM models the night side temperature as an iso-latitudinal fraction (f) of the maximum day side temperature (Maximum temperature calculated for NEATM with beaming parameter = 1). A range of f is found for different thermal parameters, which depend on the thermal inertia. NESTM diameters are compared with NEATM and radar diameters, and it is shown that NESTM may reduce the systematic bias in overestimating diameters. It is suggested that a version of the NESTM which assumes the thermal inertia = 200 S.I. units is adopted as a default model when the solar phase angle is greater than 45 degrees.Comment: 48 pages, 10 Figures, 5 Table
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