Taxation and Rotation Age under Stochastic Forest Stand Value

The paper uses both the single rotation and ongoing rotation framework to study the impact of yield tax, lump-sum tax, cash flow tax and tax on interest rate earnings on the privately optimal rotation period when forest value growth is stochastic and forest owners are either risk neutral or risk averse. In the case of risk-neutral forest owner higher yield tax raises the optimal harvesting threshold and thereby prolongs the expected rotation period. The same qualitative result holds for lump-sum tax and for the tax on interest rate earnings, while the cash flow tax is neutral. Under risk aversion the optimal harvesting threshold is lower and the expected rotation period shorter than under risk neutrality both in the single and ongoing rotation cases. Comparative statics of taxes are similar as under risk neutrality with the exception of cash flow tax, which may not be neutral anymore. Numerical results indicate that the optimal harvesting threshold both as a function of the yield tax and the forest value volatility increases more rapidly under risk neutrality than under risk aversion.optimal rotation, taxation, stochastic forest value, risk aversion

COEL: A Web-based Chemistry Simulation Framework

The chemical reaction network (CRN) is a widely used formalism to describe macroscopic behavior of chemical systems. Available tools for CRN modelling and simulation require local access, installation, and often involve local file storage, which is susceptible to loss, lacks searchable structure, and does not support concurrency. Furthermore, simulations are often single-threaded, and user interfaces are non-trivial to use. Therefore there are significant hurdles to conducting efficient and collaborative chemical research. In this paper, we introduce a new enterprise chemistry simulation framework, COEL, which addresses these issues. COEL is the first web-based framework of its kind. A visually pleasing and intuitive user interface, simulations that run on a large computational grid, reliable database storage, and transactional services make COEL ideal for collaborative research and education. COEL's most prominent features include ODE-based simulations of chemical reaction networks and multicompartment reaction networks, with rich options for user interactions with those networks. COEL provides DNA-strand displacement transformations and visualization (and is to our knowledge the first CRN framework to do so), GA optimization of rate constants, expression validation, an application-wide plotting engine, and SBML/Octave/Matlab export. We also present an overview of the underlying software and technologies employed and describe the main architectural decisions driving our development. COEL is available at http://coel-sim.org for selected research teams only. We plan to provide a part of COEL's functionality to the general public in the near future.Comment: 23 pages, 12 figures, 1 tabl