276 research outputs found
Modelling environmental effects of agriculture : the case of organic rye and grey partridge
Our optimal control model identifies economic reasons as to why farmland bird populations have dramatically declined in modern agricultural landscapes. By integrating recreational wildlife values into farm level decision-making on arable crop choice and herbicide use, we derive those economic instruments needed for creating suitable conditions for game bird species on farmland. Based on the Finnish data available on the grey partridge (Perdix perdix), we illustrate how the optimal acreage subsidy for organically-grown areas, herbicide tax rates and the hunting licence fee could be estimated in monetary terms. Finally, we discuss the benefits and costs of cultivating organic cereals which will enhance preservation of the grey partridge
Biodiversity and economic incentives in agriculture : integrating bird fauna values into decision-making
Our optimal control model identifies economic reasons as to why several farmland bird populations have dramatically declined in modern agricultural landscapes. By integrating bird fauna values into decision-making on cereal crop choice, herbicide use and hunting bag size, we derive those economic instruments needed for enhancing biodiversity on farmland and reversing the decline of grey partridge (Perdix perdix) populations. Based on the Finnish data available, we illustrate how the optimal acreage subsidy for organically-grown rye areas, the herbicide tax rate and the grey partridge hunting licence fee could be estimated in monetary terms. The procedure to derive and value the first-best policy instruments is applicable for various components of agri-environmental schemes implemented throughout the European Union
On the Arnold Conjecture and the Atiyah-Patodi-Singer Index Theorem
The Arnold conjecture yields a lower bound to the number of periodic
classical trajectories in a Hamiltonian system. Here we count these
trajectories with the help of a path integral, which we inspect using
properties of the spectral flow of a Dirac operator in the background of a
\Sp(2N) valued gauge field. We compute the spectral flow from the
Atiyah-Patodi-Singer index theorem, and apply the results to evaluate the path
integral using localization methods. In this manner we find a lower bound to
the number of periodic classical trajectories which is consistent with the
Arnold conjecture.Comment: 12 pages, references correcte
Modelling Environmental Effects of Agriculture: The Case of Organic Rye and Grey Partridge
Our optimal control model identifies economic reasons as to why farmland bird populations have dramatically declined in modern agricultural landscapes. By integrating recreational wildlife values into farm level decision-making on arable crop choice and herbicide use, we derive those economic instruments needed for creating suitable conditions for game bird species on farmland. Based on the Finnish data available on the grey partridge (Perdix perdix), we illustrate how the optimal acreage subsidy for organically-grown areas, herbicide tax rates and the hunting licence fee could be estimated in monetary terms. Finally, we discuss the benefits and costs of cultivating organic cereals which will enhance preservation of the grey partridge.environmental benefits, grey partridge, herbicides, optimal control, rye, Environmental Economics and Policy, Q57, Q18, H41,
On diversity effects of alternative agricultural policy reforms in Finland: An agricultural sector modelling approach
The aim of this study is to predict diversity effects of agricultural policy reforms in which direct aid payments are disconnected from production, and compare the outcomes with effects of such a policy in which CAP support is coupled. The study employs the dynamic regional sector model of Finnish agriculture. The sector model predicts regional land use, stocking densities, pesticide application areas, and nutrient balances
Modelling farmer’s crop choice with production externalities. The case of cultivation of rye in Finland
not availabl
An integrated simulation model to evaluate national policies for the abatement of agricultural nutrients in the Baltic Sea
This study introduces a prototype model for evaluating policies to abate agricultural nutrients in the Baltic Sea from a Finnish national point of view. The stochastic simulation model integrates nutrient dynamics of nitrogen and phosphorus in the sea basins adjoining the Finnish coast, nutrient loads from land and other sources, benefits from nutrient abatement (in the form of recreation and other ecosystem services) and the costs of agricultural abatement activities. The aim of this study is to present the overall structure of the model and to demonstrate its potential using preliminary parameters
Aspects of Duality and Confining Strings
We inspect the excitation energy spectrum of a confining string in terms of
solitons in an effective field theory model. The spectrum can be characterized
by a spectral function, and twisting and bending of the string is manifested by
the invariance of this function under a duality transformation. Both general
considerations and numerical simulations reveal that the spectral function can
be approximated by a simple rational form, which we propose becomes exact in
the Yang-Mills theory.Comment: refinement of certain argument
An integrated simulation model to evaluate national policies for the abatement of agricultural nutrients in the Baltic Sea
This study introduces a prototype model for evaluating policies to abate agricultural nutrients in the Baltic Sea from a Finnish national point of view. The stochastic simulation model integrates nutrient dynamics of nitrogen and phosphorus in the sea basins adjoining the Finnish coast, nutrient loads from land and other sources, benefits from nutrient abatement (in the form of recreation and other ecosystem services) and the costs of agricultural abatement activities. The aim of this study is to present the overall structure of the model and to demonstrate its potential using preliminary parameters. The model is made flexible for further improvements in all of its ecological and economic components. Results of a sensitivity analysis suggest that investments in reducing the nutrient runoff from arable land in Finland would become profitable only if Finland’s neighbors in the northern Baltic committed themselves to similar reductions. Environmental investments for improving water quality yield the highest returns for the Bothnian Bay and the Gulf of Finland, and smaller returns for the Bothnian Sea. In the Bothnian Bay, the abatement activities become profitable because the riverine loads from Finland represent a high proportion of the total nutrient loads. In the Gulf of Finland, this proportion is low, but the size of the coastal population benefiting from improved water quality is high.ecosystem services, nutrient abatement, Monte Carlo simulation, recreation, valuation, Environmental Economics and Policy, Research Methods/ Statistical Methods,
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