1,892 research outputs found

    Outdoor Recreation Valuation (ORVal) User Guide: Version 2.0

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    The ORVal Tool is web application developed by the Land, Environment, Economics and Policy (LEEP) Institute at the University of Exeter with support from DEFRA. It can be accessed at: http://leep.exeter.ac.uk/orval.Department for Environment, Food and Rural Affairs (Defra

    Addressing the Collective Action Problem in Multiple-purchaser PES: An Experimental Investigation of Negotiated Payment Contributions

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    This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.Involving multiple-purchasers in a PES scheme has the potential to deliver numerous benefits including cost-sharing, expanded financing and broadened scope. That few such schemes exist is evidence of a classic market failure resulting from incentives to free-ride on the payments of other purchasers. In the context of an experimental investigation, this paper explores the role of negotiation and binding pre-commitments to payments in solving that collective action problem. Our novel experimental setup involves two purchasers seeking a level of payment acceptable to a single provider while also agreeing their own individual contributions to that payment. Contrasting treatments are used to explore complexities of the conditions under which negotiations might take place including asymmetries between the purchasers, treatments with incomplete information and treatments with uncertainty over the levels of benefit. We find that those complexities change the ease with which a negotiated agreement is achieved as well as the relative size of the payoffs enjoyed by the different parties to the negotiations Our findings are generally positive, showing that under many circumstances parties to a multiple-purchaser PES can successfully negotiate a mutually agreeable schedule of payments and contributions.This project was carried out as part of the Defra Payments for Ecosystem Services (PES) Pilot Research Projects: River Fowey Improvement Scheme [NE0131]. It was also supported by a University of East Anglia studentship. Funding support is gratefully acknowledged

    Outdoor Recreation Valuation (ORVal) User Guide: Version 1.0

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    The ORVal Tool is web application developed by the Land, Environment, Economics and Policy (LEEP) Institute at the University of Exeter with support from DEFRA. It can be accessed at: http://leep.exeter.ac.uk/orval.Department for Environment, Food and Rural Affairs (Defra

    The ORVal Recreation Demand Model

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    Department for Environment, Food and Rural Affairs (Defra

    Multiple‑Purchaser Payments for Ecosystem Services: An Exploration Using Spatial Simulation Modelling

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    This is the final version. Available on open access from Springer via the DOI in this recordThis paper focuses on the issue of payments for ecosystem services (PES) mechanism design when the activity incentivised through the scheme benefits multiple groups, each of whom might be prepared to contribute to payments made through the scheme. In particular, we examine spatial coordination on the demand side of the market; that is to say, the question of which beneficiary of the PES scheme buys land-management changes on which land parcels. We show through spatial simulation modelling that it is possible for negotiation to lead to Pareto improvements when compared to solutions reached through non-cooperative strategic solutions; however, we also show that this result is not universal and only holds under certain conditions. In particular, the spatial correlation and spatial interdependence of the ecosystem service benefits are key in determining whether negotiation between beneficiaries is optimal and therefore if policy makers and designers of PES schemes should be prioritising bringing together multiple beneficiaries of ecosystem services

    Scoping the strengths and weaknesses of different auction and PES mechanisms for Countryside Stewardship

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    This is the final version. Available from Defra (Department for Environment, Food and Rural Affairs) via the link in this recordThe majority of farmers in England currently receive a fixed fee for managing their land under an agrienvironment scheme (Environmental Stewardship), which is based on an estimate of the typical income forgone by participating. The aim of this research is to explore alternative mechanisms for allocating agri-environment contracts with a view to achieving a more cost-efficient and effective use of funds. The focus is on reverse auctions, whereby farmers opt into a bidding process, offering to manage their land under prescribed management options at a price that more closely reflects their cost of doing so. The researchers have used a combination of laboratory experiments, simulation modelling and farmer workshops to consider the opportunity for efficiency gains, aspects of auction design and farmer responses to auctions. A secondary objective of the work is to explore opportunities for the private sector to engage in agrienvironment actions by leveraging match-funding where there are common goals and mutual benefits for private firms and society. This has entailed a review of the payment for ecosystem services (PES) literature and consultations with a number of relevant private firms. A particular focus for the latter has been the water companies, as they have already established some initiatives on PES around improving water quality

    Shaping bursting by electrical coupling and noise

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    Gap-junctional coupling is an important way of communication between neurons and other excitable cells. Strong electrical coupling synchronizes activity across cell ensembles. Surprisingly, in the presence of noise synchronous oscillations generated by an electrically coupled network may differ qualitatively from the oscillations produced by uncoupled individual cells forming the network. A prominent example of such behavior is the synchronized bursting in islets of Langerhans formed by pancreatic \beta-cells, which in isolation are known to exhibit irregular spiking. At the heart of this intriguing phenomenon lies denoising, a remarkable ability of electrical coupling to diminish the effects of noise acting on individual cells. In this paper, we derive quantitative estimates characterizing denoising in electrically coupled networks of conductance-based models of square wave bursting cells. Our analysis reveals the interplay of the intrinsic properties of the individual cells and network topology and their respective contributions to this important effect. In particular, we show that networks on graphs with large algebraic connectivity or small total effective resistance are better equipped for implementing denoising. As a by-product of the analysis of denoising, we analytically estimate the rate with which trajectories converge to the synchronization subspace and the stability of the latter to random perturbations. These estimates reveal the role of the network topology in synchronization. The analysis is complemented by numerical simulations of electrically coupled conductance-based networks. Taken together, these results explain the mechanisms underlying synchronization and denoising in an important class of biological models

    Seroprevalence of Hepatitis B, C and D in Vietnam: A systematic review and meta-analysis.

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    Background: Vietnam has one of the greatest disease burdens from chronic viral hepatitis. Comprehensive prevalence data are essential to support its elimination as a public health threat. Methods: We searched Medline and Embase from 1990 to 2021 for seroprevalence data relating to Hepatitis B (HBV), C (HCV) and D (HDV) in Vietnam. We estimated pooled prevalence with a DerSimonian-Laird random-effects model and stratified study populations into i) low-risk ii) high-risk exposure and iii) liver disease. We further estimated prevalence by decade and region and rates of HIV-coinfection. Findings: We analysed 72 studies, including 120 HBV, 114 HCV and 23 HDV study populations. Pooled HBV prevalence was low in blood donors (1.86% [1.82-1.90]) but high in antenatal populations (10.8% [10.1-11.6]) and adults in the general population (10.5% [10.0-11.0]). It was similar or modestly increased in groups at highest risk of exposure, suggesting the epidemic is largely driven by chronic infections acquired in childhood. HCV pooled prevalence in the general population was lower than historical estimates: 0.26% (0.09-0.51) have active infection defined by detectable antigen or HCV RNA. In contrast, there is an extremely high prevalence of active HCV infection in people who inject drugs (PWID) (57.8% [56.5-59.1]), which has persisted through the decades despite harm-reduction interventions. HDV appears mainly confined to high-risk groups. Interpretation: Blood safety has improved, but renewed focus on HBV vaccination at birth and targeted HCV screening and treatment of PWID are urgently required to meet elimination targets. Large cross-sectional studies are needed to better characterize HDV prevalence, but mass screening may not be warranted. Funding: This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors

    Femtosecond Laser-Assisted Cataract Surgery Versus Phacoemulsification Cataract Surgery (FACT): A Randomized Noninferiority Trial

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    PURPOSE: To report the 3-month results of a randomized trial (Femtosecond Laser-Assisted Cataract Trial [FACT]) comparing femtosecond laser-assisted cataract surgery (FLACS) with standard phacoemulsification cataract surgery (PCS). DESIGN: Multicenter, randomized controlled trial funded by the UK National Institute of Health Research (HTA 13/04/46/). PARTICIPANTS: Seven hundred eighty-five patients with age-related cataract. METHODS: This trial took place in 3 hospitals in the UK National Health Service (NHS). Randomization (1:1) was stratified by site, surgeon, and 1 or both eyes eligible using a secure web-based system. Postoperative assessments were masked to the allocated intervention. The primary outcome was unaided distance visual acuity (UDVA) in the study eye at 3 months. Secondary outcomes included corrected distance visual acuity, complications, and patient-reported outcomes measures. The noninferiority margin was 0.1 logarithm of the minimum angle of resolution (logMAR). ISRCTN.com registry, number ISRCTN77602616. MAIN OUTCOME MEASURES: We enrolled 785 participants between May 2015 and September 2017 and randomly assigned 392 to FLACS and 393 to PCS. At 3 months postoperatively, mean UDVA difference between treatment arms was -0.01 logMAR (-0.05 to 0.03), and mean corrected distance visual acuity difference was -0.01 logMAR (95% confidence interval [CI], -0.05 to 0.02). Seventy-one percent of both FLACS and PCS cases were within ±0.5 diopters (D) of the refractive target, and 93% of FLACS and 92% of PCS cases were within ±1.0 D. There were 2 posterior capsule tears in the PCS arm and none in the FLACS arm. There were no significant differences between arms for any secondary outcome. CONCLUSIONS: Femtosecond laser-assisted cataract surgery is not inferior to conventional PCS surgery 3 months after surgery. Both methods are as good in terms of vision, patient-reported health, and safety outcomes at 3 months. Longer-term outcomes of the clinical effectiveness and cost-effectiveness are awaited

    The Financial and Environmental Consequences of Renewable Energy Exclusion Zones

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    This is the final version. Available on open access from Springer via the DOI in this recordAs countries decarbonise, the competition for land between energy generation, nature conservation and food production will likely increase. To counter this, modelling, and sometimes energy policies, use exclusion zones to restrict energy deployment from land deemed as important to society. This paper applies the spatially-explicit ADVENT-NEV model to Great Britain to determine the cost imposed on the energy system when either environmental or food production exclusion zones are applied. Results show that exclusion zones impose a cost of up to £0.63 billion (B), £19.17 B and £1.33 B for the solar, wind, and bioenergy pathways. These costs give an indication of the value being placed on protecting these areas of land. When multiple exclusions are imposed on bioenergy, the high pathway is infeasible indicating a more flexible approach may be needed to meet net zero ambitions. The model also shows how the value of ecosystem services changes when exclusion zones are applied, highlighting how some exclusions increase non-market costs whereas others decrease them. In several cases exclusion zones are shown to increase social costs, the opposite of their intended use. For these exclusions to be justifiable, the unobserved values missing from the model must be as large as these increases
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