A bioeconomic model for estimating the optimal level of deer and tag sales

This paper presents a dynamic model that determines the optimal number of deer hunting permit sales, subject to the objective of maximizing the discounted economic benefits stream from both the consumptive and nonconsumptive uses of deer. This bioeconomic model integrates economic benefits estimated using the dichotomous choice contingent valuation method with biological growth constraints on deer. Using a hunting zone in California as a case study, the model found that the optimal levels of buck hunting permits sold should change on a rotational basis over time and that the current practice of not selling doe hunting permits for that zone is non optimal.     

A bioeconomic view of the transition to agriculture: a comment

Abstract Arthur Robson (2010) presents an ingenious model to explain why the standard of living apparently fell during the Neolithic transition from hunter‐gathering to agriculture. His demonstration relies on a production function that has a strong property with regard to technical change. This note shows how Robson’s result can be obtained using a more familiar set of restrictions on technical change. Under these restrictions, an improvement in technology will cause parents to invest less per child and the standard of living will fall.     

Measuring potential profits in a bioeconomic model of the mixed demersal fishery in the North Sea

This paper measures for potential profit in the North Sea mixed demersal fishery for cod, haddock and whiting. Dynamic bioeconomic models for three UK fisheries are developed, incorporating both population dynamics and economic structure. Actual profit in 2006, for the three UK fleets included in the analysis, is estimated at ??10.3?million. If the TAC remains unchanged but vessels are allowed to harvest at near efficient levels with fleet size reduced accordingly, potential profit is measured at ??34.5?million. If demersal stocks are allowed to recover to near optimal levels potential UK profit exceeds ??185?million. This indicates substantial profit dissipation due to overcapacity and stock depletion in the fishery. The results of the paper should be of policy interest and will add to the empirical literature on resource profits in mixed demersal fisheries.     

A bioeconomic view of the Neolithic transition to agriculture

Abstract .  Adoption of agriculture at the expense of hunting and gathering was the dramatic precondition for all modern civilization. Recent data suggest that, because of this transition, humans initially were more disease prone, smaller, less nourished, and shorter-lived. To explain why individuals chose agriculture over hunting and gathering, this paper develops a simple model of the evolution of preferences over the quality and quantity of children, as would have been generated by our long history as a species. These preferences would have induced the choice of agriculture, but also would have led to these otherwise puzzling health effects.     

An options based bioeconomic model for biological and chemical control of invasive species

The management of non-native invasive species is a complex but crucial task given the potential for economic and environmental damages. For many invasions the development of socially optimal control strategies requires more than is offered by the single-species, single-control models that have dominated this area of research. We develop a general stochastic optimal control framework that accommodates multiple interacting species while accounting for uncertainty in the temporal population dynamics. This extension to the current line of bioeconomic control models allows for the design of optimal integrated pest management strategies that utilize both chemical and biological controls in an environment of uncertainty and irreversibility. We demonstrate the benefits of combining chemical and biological controls in long term management strategies through a case study of the hemlock wooly adelgid (Adelges tsugae) infestation in the eastern United States. In this application we find that the introduction of natural predators is usually sufficient to manage the infestation, though chemical insecticides can play an important role when detection of the infestation is delayed or when the biological control agent does not sufficiently increase mortality of the invasive species.     

Breeding hybrid strategies: optimal behaviour for oligopolists

Oligopolistic pricing decisions-in which the choice variable is not dichotomous as in the simple prisoner's dilemma but continuous-have been modeled as a generalized prisoner's dilemma (GPD) by Fader and Hauser, who sought, in the two MIT Computer Strategy Tournaments, to obtain an effective generalization of Rapoport's Tit for Tat for the three-person repeated game. Holland's genetic algorithm and Axelrod's representation of contingent strategies provide a means of generating new strategies in the computer, through machine learning, without outside submissions.The paper discusses how findings from two-person tournaments can be extended to the GPD, in particular how the author's winning strategy in the Second MIT Competitive Strategy Tournament could be bettered. The paper provides insight into how oligopolistic pricing competitors can successfully compete, and underlines the importance of niche strategies, successful against a particular environment of competitors.Bootstrapping, or breeding strategies against their peers, provides a means of examining whether repetition leads to cooperation: we show that it can, under certain conditions, for simple and extended two- and three-person GPD repeated games. The paper concludes with a discussion of the relationship between Selten's trembling-hand perfect equilibrium and Maynard Smith's evolutionarily stable strategies, with practical simulations of successful and unsuccessful invasions by new strategies.     

A discrete model of optimal economic growth

Contrary to most of the literature on optimal economic growth a discrete rather than a continuous model is investigated. It is shown that in such a discrete model it is easy to account for relatively freely changing functions and parameters. Thus, the production function, labor, the investment ratio, and the parameters for time preference, marginal utility, and depreciation are all allowed to depend on time. Using discrete dynamic programming methods, optimal investment policies are determined explicitly. These generalize important results from previous literature on optimal economic growth.     

A waste management model for optimal recycling-landfilling policies under macroeconomic conditions

This research provides a waste management model in the presence of macroeconomic conditions. An optimal control problem which integrates the recycling-landfilling decision with industry supply-demand dynamics is designed to achieve the value-maximizing objective. The model simultaneously considers idiosyncratic technical and aggregate demand shocks, while the stoppage time for landfill use is assumed to follow a Cox process with the intensity function of a firm's total waste collection. The closed-form solution of the optimal recycling ratio is also derived. The results suggest that when macroeconomic effects are neglected, optimal recycling ratios tend to be underestimated.     

On the solution of a stochastic optimal growth model

This note discusses a stochastic optimal growth model in which the optimal paths can be obtained by a simple direct argument. The structural characteristics of the model are the infinite horizon, the form of the instantaneous utility function, and uncertainty as a Wiener process in a linear production constraint. The note explains that, for optimality, at each point in time a formally identical problem must be solved. This implies that the optimal saving ratio must be constant.A proof, employing the rules of stochastic calculus, that the ensuing paths are the unique globally optimal paths is also given.We are very grateful to two referees of this journal for their invaluable comments and suggestions.     

A new necessary condition for implementation in iteratively undominated strategies

We uncover a new necessary condition for implementation in iteratively undominated strategies by mechanisms that satisfy the “best element property” where for each agent, there exists a strategy profile that gives him the highest payoff in the mechanism. This class includes finite and regular mechanisms. We conclude that either the quasilinearity-like assumptions of available sufficiency results cannot be completely dispensed with or some mechanisms that do not satisfy the best element property must be employed. We term the condition “restricted deception-proofness.” It requires that, in environments with identical preferences, the social choice function be immune to all deceptions, making it then stronger than incentive compatibility. In some environments the conditions for (exact or approximate) implementation by mechanisms satisfying the best element property are more restrictive than previously thought.     

A nonsmooth, nonconvex model of optimal growth

This paper analyzes the nature of economic dynamics in a one-sector optimal growth model in which the technology is generally nonconvex, nondifferentiable, and discontinuous. The model also allows for irreversible investment and unbounded growth. We develop various tools to overcome the technical difficulties posed by the generality of the model. We provide sufficient conditions for optimal paths to be bounded, to converge to zero, to be bounded away from zero, and to grow unboundedly. We also show that under certain conditions, if the discount factor is close to 1, any optimal path from a given initial capital stock converges to a small neighborhood of the golden rule capital stock, at which sustainable consumption is maximized. If it is maximized at infinity, then as the discount factor approaches 1, any optimal path either grows unboundedly or converges to an arbitrarily large capital stock.     

Shock treatment for inflation: A note on optimal policy in a Buiter/Miller model

In exchange rate-overshooting models, of the kind recently used by Buiter and Miller to analyse the cost of reducing inflation, an unexpected change in monetary policy typically induces jumps in the exchange rate and (maybe) prices. This note illustrates with a numerical example a money-stock policy which reduces inflation instantly and permanently to zero without a jump in exchange rates or prices. This policy is optimal if the objective function contains no time-discounting and depends on the level of output and the squared inflation rate. It is also optimal if only inflation enters the objective function.     

中国经济发展进入新阶段:挑战与战略

中国经济正处于一个重要的转折时期 ,国际经验表明 ,在这个时期继续保持较快增长的难度加大。中国面临一些发展中国家共有的条件和问题 ,也面临独有的挑战与机遇。要保持我国经济继续较快增长 ,就要立足国情 ,立足当代 ,选择正确的发展战略 ,包括坚持继续深化改革 ,消除增长的体制障碍 ;更加注重就业问题 ,保证经济增长的共享性和社会稳定 ;促进形成资源节约型增长方式 ,使经济增长可持续 ;更加注重扩大内需 ,降低开放性增长动力减弱的影响 ;加快发展服务业 ,提高服务业对增长和就业的贡献率 ;加大对重大战略问题的科技投入 ,解决我国经济增长面临的技术瓶颈 ;更多关注公平和稳定问题 ,减少发展的阻力和摩擦 ;维护并积极推动全球资源、技术与产品的自由贸易体制 ,为我国中长期经济发展争取较好的外部环境。     

The dynamics of optimal abatement strategies for multiple pollutants—An illustration in the Greenhouse

We investigate optimal abatement strategies for cumulative and interacting pollutants. We show that different decay rates can cause non-monotonic behavior in the optimal paths of emissions, the aggregate level of pollution, and even the relative optimal price for emissions. This contrasts strikingly with the case of a single pollutant. The results are illustrated by numerical simulations, first for instructive fictitious and second for more realistic parameters mimicking the greenhouse problem. The results add to the skepticism existing about whether the concept of global warming potential is a useful indicator for the optimal relative abatement of different GHGs over time. In fact, we show that a constant index suitable for comparing dynamically different pollutants with respect to their economic harmfulness does not exist.     

Identifying optimal contingent fiscal policies in a business cycle model

Optimal fiscal policy is indeterminate in a dynamic and stochastic environment. The complete characterization of the fiscal policy requires the use of identification constraints. In the literature either capital taxes or debt have been restricted to be not contingent on the state of nature. We propose a different type of identification constraints to have both policy variables state-contingent. Three alternative identification conditions are considered: (i) restrictions on the dynamic and stochastic behavior of the debt path; (ii) an exogenous debt path, and (iii) an exogenous belief function. The main result indicates that the optimal capital tax is zero and constant over the business cycle for any of the identification conditions used, suggesting that is optimal for the government to use debt return as a shock absorber, keeping capital taxes constant. The result is quite different from the previous literature, which obtains very volatile capital taxes. JEL Classification: E62, H21. We are grateful to Alfonso Novales, Víctor Ríos-Rull, Javier Vallés and two anonymous referees for helpful comments and suggestions. We acknowledge financial support from Spanish Ministerio de Ciencia y Tecnología (Ruiz and Pérez: BEC 2003-039; Manzano: BEC 2002-01995). Baltasar Manzano also acknowledges support from Xunta de Galicia (PGIDIT03PXIC30001PN, PGIDIT03CSO30001PR).     

Stability of stochastic optimal growth models: a new approach

The paper proposes an Euler equation technique for analyzing the stability of differentiable stochastic programs. The main innovation is to use marginal reward directly as a Foster-Lyapunov function. This allows us to extend known stability results for stochastic optimal growth models, both weakening hypotheses and strengthening conclusions.