A Dynamic Model of Mesh Size Regulatory Compliance in Fisheries

The violation of fishing regulations is a criminal activity that leads to depleting fish stock levels across the world. This paper focuses on fishing violations in developing countries. In particular, the paper analyses the use of a fishing net with illegal mesh size in a two regimes, namely a management regime where each community claims a territorial use right over the fishery and a regulated open access regime. This paper employs a dynamic model for fishery crimes that involve time and punishment to analyse the use of a net with illegal mesh size in the different regimes. We found that if the community has territorial use right, the illegal activity in addition to decreasing the intrinsic growth rate and the cost of fishing would increase the community’s effective discount rate and consequently result in a much lower equilibrium stock and harvest relative to the situation where the community only use nets with the legal mesh size. Furthermore, under a regulated open access management the equilibrium stock will be lower if a community violates the regulation and the proportionate change in the risk of punishment is higher than the proportionate change in the harvest potential. Moreover, the optimum penalty for violation must be set higher in the open access fishery relative to the complete territorial use right management regime.Crime; Dynamic Model; Fishery; Regulation

A Dynamic Model of Mesh Size Regulatory Compliance

This paper employs a dynamic model for crimes that involve time and punishment to analyze the use of a net with illegal mesh size in a management regime where each community claims territorial use right over a fishery but has a discount rate that may differ from the social discount rate. The equilibrium stock and harvest levels are found to be much lower if the regulation is violated. Moreover, the optimal penalty for violation must be decreasing in the shadow cost of taking the risk to fish illegally, and increasing the risk of punishment increases the equilibrium stock level.crime, dynamic model, fishery, regulation, Resource /Energy Economics and Policy,

On the Economics of Rational Self-Medication

It has been established in the medical literature that self-medicating with imperfect information about either the use of a genuine or counterfeit drug or based on wrong self-diagnosis of ailment, which is predominant especially in developing countries, is a risky investment in health capital. This paper models the decision to self-medicate and the demand for self-medicated drugs. We suppose that investment in self-medication depends on the perception of its effectiveness. The results obtained show that the decision to self-medicate depends on the relative price and perceived effectiveness of self-medication, the elasticity of the shadow value of health with respect to the quantity of health capital, and the relative effectiveness of self-medication in reducing the unpredictable changes in health capital. Furthermore, if an individual self-medicates, self-medication becomes a normal good: it increases if income increases; and it obeys the law of demand (i.e. it increases if its price, relative to that of the risk-free medication, decreases). Moreover, we have shown that some optimum subsidy can discourage self-medication.Health Production, Self-Medication, Risky Investment, Government Policy, Dynamic Analysis

The Media, Accountability and Civic Engagement in Africa

human development, democracy

A proof that tidal heating in a synchronous rotation is always larger than in an asymptotic nonsynchronous rotation state

In a recent paper, Wisdom (2007, Icarus, in press) derived concise expressions for the rate of tidal dissipation in a synchronously rotating body for arbitrary orbital eccentricity and obliquity. He provided numerical evidence than the derived rate is always larger than in an asymptotic nonsynchronous rotation state at any obliquity and eccentricity. Here, I present a simple mathematical proof of this conclusion and show that this result still holds for any spin-orbit resonance.Comment: 10 pages, 0 figure. accepted for publication in "Icarus

A Fast and Accurate Universal Kepler Solver without Stumpff Series

We derive and present a fast and accurate solution of the initial value problem for Keplerian motion in universal variables that does not use the Stumpff series. We find that it performs better than methods based on the Stumpff series.Comment: 10 pages, 7 figures. Accepted by MNRAS, resubmitted because of a typo in the title, added author affiliation

Decreasing Computing Time with Symplectic Correctors in Adaptive Timestepping Routines

It has previously been shown that varying the numerical timestep during a symplectic orbital integration leads to a random walk in energy and angular momentum, destroying the phase space-conserving property of symplectic integrators. Here we show that when altering the timestep symplectic correctors can be used to reduce this error to a negligible level. Furthermore, these correctors can also be employed to avoid a large error introduction when changing the Hamiltonian's partitioning. We have constructed a numerical integrator using this technique that is nearly as accurate as widely used fixed-step routines. In addition, our algorithm is drastically faster for integrations of highly eccentricitic, large semimajor axis orbits, such as those found in the Oort Cloud.Comment: Accepted to AJ, 29 pages, 8 figure

The Bioeconomics of Conservation Agriculture and Soil Carbon Sequestration in Developing Countries

Improving soil carbon through conservation agriculture in developing countries may generate some private benefits to farmers, as well as sequester carbon emissions, which is a positive externality to society. Leaving crop residue on the farm has become an important option in conservation agriculture practice. However, in developing countries, using crop residue for conservation agriculture has the opportunity cost of feed for livestock. In this paper, we model and develop an expression for an optimum economic incentive that is necessary to internalize the positive externality. A crude value of the tax is calculated using data from Kenya. We also empirically investigated the determinants of the crop residue left on the farm and found that it depends on the cation exchange capacity (CEC) of the soil, the prices of maize, whether extension officers visit the plot or not, household size, the level of education of the household head, and alternative cost of soil conservation.conservation agriculture, soil carbon, climate change, bioeconomics, Kenya

Ostracism and Common Pool Resource Management in a Developing Country: Young Fishers in the Laboratory

This paper investigates how the possibility to ostracise, which is a familiar punishment mechanism to subjects in an experiment, affects harvest in a common pool resource experiment. The experiment was framed as a fishing problem and the subjects were young fishers in Ghana. We find that the introduction of the possibility to ostracise other members of a group at a cost to the remaining members of a group decreased over-fishing significantly in comparison with the situation where ostracism was not possible. The ostracism was based on at least 50 percent voting rule. Moreover, the subjects demonstrated a strong desire to ostracise those who overfished.Common Pool Resource; Experiment; Ostracism; Fishers