NOAH'S NONCONCAVITY: ON THE EXISTENCE OF NONTRIVIAL INTERIOR SOLUTIONS TO THE PROBLEM OF COST‐EFFECTIVE CONSERVATION PLANNING

Abstract The idea that species loss diminishes future information flows is a cornerstone of arguments for conservation planning. In his seminal work entitled The Noah's Ark Problem, Weitzman [1998] examines the problem of cost‐effective conservation planning from a theoretical perspective accounting for the affect planning has on the expected size of the biosphere's informative potential. This paper extends Weitzman's analysis by examining how his conclusions are altered by the introduction of a conservation authority that considers the value of information contained in the biosphere. Introducing nonquasiconcave preferences for the information contained in each species substantially modifies the characterization of a cost‐effective conservation plan. In particular, I find that a cost‐effective plan generally includes partial funding for many species and funds no species completely. This investigation is motivated by theoretical contributions to the information economics literature, a la Radner and Stiglitz [1984] , showing that the value function for information tends to exhibit increasing returns.     

THE EFFECT OF INFORMATION ON A STOCHASTIC,SPATIALLY DISTRIBUTED FISHERY

ABSTRACT. Survival rates and carrying capacities in a fishery may be strongly affected by variations in climatic factors. When the stock is under the control of a single manager, information about the stochastic growth parameters leads to improved economic returns. However, when the stock is transboundary, additional information concerning the stochastic parameters can lead to over harvesting and in turn to lower economic returns. When the harvests are taken sequentially by more than one fleet, additional information will benefit the first harvester while harming those who follow.     

Cubic Splines on Curved Spaces

We consider a second-order problem in the calculus of variations,with an application to robotics in mind. The analysis is carriedout on a general Riemannian manifold M and then specializedto the case where M is the Lie group SO(3) of rotations in R³.For SO(3), the Euler-Lagrange equations reduce to interestingnonlinear systems of ordinary differential equations in R³.     

NATURAL RESOURCE MODELING: ALLOWING FOR INCONSTANT PROBABILITY OF DETECTION AND FREQUENCY MEASURES OF VIOLATION WITHIN DYNAMIC DETERRENCE FISHERY MODELS

Abstract. The dynamic deterrence model (DDM) represents an analytical framework widely used for analyzing compliance with fishery regulations aiming for sustainable fishery management. However, applications of the DDM have so far been limited to the case of constant probability of detection that assumes independence of the length of time to detection. This paper modifies the DDM to allow for more flexible and broader specification by introducing, for the first time, two important variables to the supply of offences function, namely evasion activity and enforcement efforts and accommodating inconstant probability of detection specifications. Determinants of probability of detection are specified and important potential extensions of the modified DDM are discussed in this paper. The relative magnitude of the effects of each of these determinants on probability of detection, however, remains an important empirical question that requires further investigation for prioritization of policy actions.     

Computer simulations of adsorbed liquid crystal films

The structures adopted by adsorbed thin films of Gay-Beme particles in the presence of a coexisting vapour phase are investigated by molecular dynamics simulation. The films are adsorbed at a flat substrate which favours planar anchoring, whereas the nematic-vapour interface favours normal alignment. On cooling, a system with a high molecule-substrate interaction strength exhibits substrate-induced planar orientational ordering and considerable stratification is observed in the density profiles. In contrast, a system with weak molecule-substrate coupling adopts a director orientation orthogonal to the substrate plane, owing to the increased influence of the nematic-vapour interface. There are significant differences between the structures adopted at the two interfaces, in contrast with the predictions of density functional treatments of such systems.