Landfill Construction and Capacity Expansion

We study the optimal capacity and lifetime of landfills taking into account their sequential nature.Such an optimal capacity is characterized by the so-called Optimal Capacity Condition.Particular versions of this condition are obtained for two alternative settings: first, if all the landfills are to have the same capacity, and second, if each of them is allowed to have a different capacity.In the second case we obtain an Optimal Control problem, with mixed elements of both continuous and discrete time.The resulting optimization problems involve dividing a time horizon of planning into several subintervals of endogenously decided length.The results obtained may be useful to address other economic problems such as private and public investments, consumption decisions on durable goods, etc.investements;resources;capacity;costs

On Recycling and Technological Externalities

recycling;natural resources;production set;externalities

Intertemporal and Spatial Location of Disposal Facilities

Optimal capacity and location of a sequence of land.lls are studied, and the interactions between both decisions are pointed out.The decision capacity has some spatial implications, because it a.ects the feasible region for the rest of land.lls, and some temporal implications, because the capacity determines the lifetime of the land.ll and hence the instant of time where next land.lls will need to be constructed.Some general mathematical properties of the solution are provided and interpreted from an economic point of view.The resulting problem turns out to be no convex and therefore it can not be solved by conventional optimization techniques.Some global optimization methods are used to solve the problem in a particular case, in order to illustrate the behavior of the solution depending on parameter values.Landfilling;Optimal Capacity;Optimal Location;Global Optimization

Performing an Environmental Tax Reform in a regional Economy. A Computable General Equilibrium

We use a Computable General Equilibrium model to simulate the effects of an Environmental Tax Reform in a regional economy (Andalusia, Spain).The reform involves imposing a tax on CO2 or SO2 emissions and reducing either the Income Tax or the payroll tax of employers to Social Security, and eventually keeping public deficit unchanged.This approach enables us to test the so-called double dividend hypothesis, which states that this kind of reform is likely to improve both environmental and non-environmental welfare.In the economy under analysis, an employment double dividend arises when the payroll tax is reduced and, if CO2 emissions are selected as environmental target, a (limited) strong double could also be obtained.No double dividend appears when Income Tax is reduced to compensate the environmental tax.environmental tax;general equilibrium;regional economics;tax reform;dividends

Intertemporal and Spatial Location of Disposal Facilities

Optimal capacity and location of a sequence of land.lls are studied, and the interactions between both decisions are pointed out.The decision capacity has some spatial implications, because it a.ects the feasible region for the rest of land.lls, and some temporal implications, because the capacity determines the lifetime of the land.ll and hence the instant of time where next land.lls will need to be constructed.Some general mathematical properties of the solution are provided and interpreted from an economic point of view.The resulting problem turns out to be no convex and therefore it can not be solved by conventional optimization techniques.Some global optimization methods are used to solve the problem in a particular case, in order to illustrate the behavior of the solution depending on parameter values.

Performing an Environmental Tax Reform in a regional Economy. A Computable General Equilibrium

We use a Computable General Equilibrium model to simulate the effects of an Environmental Tax Reform in a regional economy (Andalusia, Spain).The reform involves imposing a tax on CO2 or SO2 emissions and reducing either the Income Tax or the payroll tax of employers to Social Security, and eventually keeping public deficit unchanged.This approach enables us to test the so-called double dividend hypothesis, which states that this kind of reform is likely to improve both environmental and non-environmental welfare.In the economy under analysis, an employment double dividend arises when the payroll tax is reduced and, if CO2 emissions are selected as environmental target, a (limited) strong double could also be obtained.No double dividend appears when Income Tax is reduced to compensate the environmental tax.

Evolution of virulence: triggering host inflammation allows invading pathogens to exclude competitors.

Virulence is generally considered to benefit parasites by enhancing resource-transfer from host to pathogen. Here, we offer an alternative framework where virulent immune-provoking behaviours and enhanced immune resistance are joint tactics of invading pathogens to eliminate resident competitors (transferring resources from resident to invading pathogen). The pathogen wins by creating a novel immunological challenge to which it is already adapted. We analyse a general ecological model of 'proactive invasion' where invaders not adapted to a local environment can succeed by changing it to one where they are better adapted than residents. However, the two-trait nature of the 'proactive' strategy (provocation of, and adaptation to environmental change) presents an evolutionary conundrum, as neither trait alone is favoured in a homogenous host population. We show that this conundrum can be resolved by allowing for host heterogeneity. We relate our model to emerging empirical findings on immunological mediation of parasite competition

The size of chi = arg (-Vts Vtb* Vcs* Vcb) and physics beyond the Standard Model

We analyse the allowed range of values of chi, both in the Standard Model and in models with New Physics, pointing out that a relatively large value of chi, e.g. of order lambda, is only possible in models where the unitarity of the 3x3 Cabibbo-Kobayashi-Maskawa matrix is violated through the introduction of extra Q=2/3 quarks. We study the interesting case where the extra quark is an isosinglet, determining the allowed range for chi and the effect of a large chi on various low-energy observables, such as CP asymmetries in B meson decays. We also discuss the correlated effects which would be observable at high energy colliders, like decays t -> cZ, modifications of the cross section and forward-backward asymmetry in e+ e- -> ttbar and the direct production of a new quark.Comment: LaTeX, 19 pages, 6 PS figures. Section 3 expanded. Version to be published in NP