Reducing Acidification: The Benefits of Increased Nature Quality. Investigating the Possibilities of the Contingent Valuation Method

In order to complete cost benefit analyses of acidification policies, an attempt was made to monetarize the benefits of increased nature quality. So far, several benefits of acidification abatement, such as reduced health risks, had been determined, but the benefits of increased nature quality were lacking, although nature is actually one of the most important reasons for abating acidification in the Netherlands. This study shows that CVM can be used to estimate two specific benefits of increased nature quality due to acidification abatement: the non-use value and the recreational perception value. For other benefits, other valuation methods are needed. This study also shows that CVM is not suited for specifying benefits of different acidification scenarios, which differ little in physical effects on ecosystems. If abatement scenarios are rather extreme, it may be possible to differentiate benefits per scenario. A CVM questionnaire was designed to determine the difference between the welfare generation of healthy ecosystems not suffering from acidification and unhealthy ecosystems affected by acidification. A striking result of the pre test was that all respondents were familiar with the environmental theme of acidification. The results of the pre test suggest that the benefits of nature may be quite large and that they should therefore not be overlooked.Acidification, Biodiversity, Economic value, Nature, CVM, Non use value

A single-item continuous double auction game

A double auction game with an infinite number of buyers and sellers is introduced. All sellers posses one unit of a good, all buyers desire to buy one unit. Each seller and each buyer has a private valuation of the good. The distribution of the valuations define supply and demand functions. One unit of the good is auctioned. At successive, discrete time instances, a player is randomly selected to make a bid (buyer) or an ask (seller). When the maximum of the bids becomes larger than the minimum of the asks, a transaction occurs and the auction is closed. The players have to choose the value of their bid or ask before the auction starts and use this value when they are selected. Assuming that the supply and demand functions are known, expected profits as functions of the strategies are derived, as well as expected transaction prices. It is shown that for linear supply and demand functions, there exists at most one Bayesian Nash equilibrium. Competitive behaviour is not an equilibrium of the game. For linear supply and demand functions, the sum of the expected profit of the sellers and the buyers is the same for the Bayesian Nash equilibrium and the market where players behave competitively. Connections are made with the ZI-C traders model and the $k$-double auction.Comment: 37 pages, 15 figure

The Socio-Economic Value of Natural Riverbanks in the Netherlands

Ecologists and economists both use a different approach to determine the value of nature. Its ecological value can be measured using criteria like rarity and diversity of species in an ecosystem. The economic value can be determined using non-market valuation techniques. This paper focuses on an empirical application of the Contingent Valuation Method (CVM) to find out whether this valuation method is a suitable method to estimate the economic value of natural riverbanks in the Netherlands. Natural riverbanks will provide habitat for species that particularly depend on the land water transit area. Since common riverbanks do not provide this habitat, natural river banks increase biodiversity in the Netherlands. On the basis of technical and ecological characteristics nine different types of natural riverbanks were distinguished. For each type a laymen description was made. This description served as a basis for economic valuation by means of CVM. The results of the CVM study shows that the average willingness to pay for non-use of a natural riverbank varied between 16 and 25 Dutch guilders per household year. The willingness to pay for recreational use ranged from 1,07 to 2,50 guilders per visit. The generated outcomes proved to be consistent with results from other studies. At first sight, the economic value of natural riverbanks seemed to be higher than their construction and maintenance cost.Nature friendly river banks, Land water interactions, Economic value, Nature, CVM, Non-use value

Reducing Acidification: The Benefits of Increased Nature Quality. Investigating the Possibilities of the Contingent Valuation Method

In order to complete cost benefit analyses of acidification policies, an attempt was made to monetarize the benefits of increased nature quality. So far, several benefits of acidification abatement, such as reduced health risks, had been determined, but the benefits of increased nature quality were lacking, although nature is actually one of the most important reasons for abating acidification in the Netherlands. This study shows that CVM can be used to estimate two specific benefits of increased nature quality due to acidification abatement: the non-use value and the recreational perception value. For other benefits, other valuation methods are needed. This study also shows that CVM is not suited for specifying benefits of different acidification scenarios, which differ little in physical effects on ecosystems. If abatement scenarios are rather extreme, it may be possible to differentiate benefits per scenario. A CVM questionnaire was designed to determine the difference between the welfare generation of healthy ecosystems not suffering from acidification and unhealthy ecosystems affected by acidification. A striking result of the pre test was that all respondents were familiar with the environmental theme of acidification. The results of the pre test suggest that the benefits of nature may be quite large and that they should therefore not be overlooked

A Solvable Nonlinear Reaction-Diffusion Model

We construct a coupled set of nonlinear reaction-diffusion equations which are exactly solvable. The model generalizes both the Burger equation and a Boltzman reaction equation recently introduced by Th. W. Ruijgrok and T. T. Wu.Comment: 6 pages, LATe

Spontaneous emission of a nanoscopic emitter in a strongly scattering disordered medium

Fluorescence lifetimes of nitrogen-vacancy color centers in individual diamond nanocrystals were measured at the interface between a glass substrate and a strongly scattering medium. Comparison of the results with values recorded from the same nanocrystals at the glass-air interface revealed fluctuations of fluorescence lifetimes in the scattering medium. After discussing a range of possible systematic effects, we attribute the observed lengthening of the lifetimes to the reduction of the local density of states. Our approach is very promising for exploring the strong three-dimensional localization of light directly on the microscopic scale.Comment: 9 pages, 4 figure

States of the Dirac equation in confining potentials

We study the Dirac equation in confining potentials with pure vector coupling, proving the existence of metastable states with longer and longer lifetimes as the non-relativistic limit is approached and eventually merging with continuity into the Schr\"odinger bound states. We believe that the existence of these states could be relevant in high energy model construction and in understanding possible resonant scattering effects in systems like Graphene. We present numerical results for the linear and the harmonic cases and we show that the the density of the states of the continuous spectrum is well described by a sum of Breit-Wigner lines. The width of the line with lowest positive energy, as expected, reproduces very well the Schwinger pair production rate for a linear potential: we thus suggest a different way of obtaining informations on the pair production in unbounded, non uniform electric fields, where very little is known.Comment: 4 page

Equivariant singularity theory with distinguished parameters: Two case studies of resonant Hamiltonian systems

We consider Hamiltonian systems near equilibrium that can be (formally) reduced to one degree of freedom. Spatio-temporal symmetries play a key role. The planar reduction is studied by equivariant singularity theory with distinguished parameters. The method is illustrated on the conservative spring-pendulum system near resonance, where it leads to integrable approximations of the iso-energetic Poincaré map. The novelty of our approach is that we obtain information on the whole dynamics, regarding the (quasi-) periodic solutions, the global configuration of their invariant manifolds, and bifurcations of these.

Resonances in a spring-pendulum: algorithms for equivariant singularity theory

A spring-pendulum in resonance is a time-independent Hamiltonian model system for formal reduction to one degree of freedom, where some symmetry (reversibility) is maintained. The reduction is handled by equivariant singularity theory with a distinguished parameter, yielding an integrable approximation of the Poincaré map. This makes a concise description of certain bifurcations possible. The computation of reparametrizations from normal form to the actual system is performed by Gröbner basis techniques.