Rambling Ralf Looks at Budworm Optimization

When work on the budworm started at IIASA last year, considerable emphasis was placed on the sad fact that myopic management has led to explosive outbreak conditions. It seems that the government has been spraying hell out of each outbreak area as it appears, with little thought for large scale spatial consequences. In a great leap sideways, the IIASA groups managed to formalize this myopic viewpoint with site optimization by dynamic programming; it should come as no surprise that (1) the formal myopic solutions closely resemble actual practice (managers are not that stupid), and (2) for New Brunswick as a whole, the myopic optimization still gives poor results (trotting blindly toward a brick wall is not very different from running at it full speed). There have been some attempts to temper the optimization by inserting different objective functions and multiarea constraints on total cutting and spraying, but the results are not very encouraging. Some totally different approach to the optimization is clearly needed, if the study is to avoid going all the way back to brute force searching methods involving gaming simulations. My interest in this note is to suggest a possible optimization procedure based on the notion that any optimal solution will involve some closed loop "control law" to specify actions as a function of system state (or output observations extracted from the state)

The Salmon Case Study: An Overview

This paper is intended as a general perspective on the Salmon Case Study for 1974-75. We review the reasons for choosing the case, indicate how salmon management policy has evolved to the present day, and describe the several research strategies that we are following in attempting to generate alternative policies for the future. We hope that the framework outlined here will prove more generally applicable to problems of renewable resource management

Identification of Potential Impacts of Resource Development Programs. The Need for a New Paradigm

With rising concern for environmental and natural resource problems over the past decade, considerable effort has been devoted to methodologies for environmental impact assessment and integrated development planning. While some superficially new approaches have appeared (e.g., simulation, cross impacts analysis) for handling larger problems with more interrelated factors, the tendency has been to cling very tenaciously to a basic paradigm or world view concerning the dilution of impacts over space and time and between major subsystems (e.g., ecological, economic). Most often this world view is either not recognized at all, or is buried in technical jargon so as to appear unimportant. One is often reminded of the children's story about why ostriches bury their heads in the sand. The intent of this paper is to critically examine the "dilution of impacts" paradigm. I first attempt to define it more clearly by reference to an alternative viewpoint. Then some examples are presented to suggest that it is becoming an increasingly dangerous and incorrect way to look at the world. I next examine some general mechanisms in modern society that make the paradigm invalid; these mechanisms suggest new directions to look in planning and impact assessment studies

Methodological Problems in the Modeling and Analysis of Ecological Systems

I would like to give you an overview of basic ecological modeling and analysis problems by discussing three things. First, I will try to explain the general attitude of systems-oriented ecologists towards their subject matter. This is a different perspective from that of many here, and we will almost certainly fail to understand each other if you imagine us to be, say, economists with an interest in animals. Second, I will review those structural characteristics of ecological systems which have made their analysis particularly difficult. We like to think that it is at least in part these difficulties which have kept us rather behind the rest of you in a number of methods-related areas. Finally, I'll give a brief picture of the kinds of dynamic and stability behavior which we encounter in real and model ecological systems, using as examples cases presently under investigation at IIASA and' available for study at this workshop

A Control System for Intraseason Salmon Management

Management of Salmon populations in large rivers like the Skeena (B.C., Canada) is usually done in two stages. First long range goals and data are used to set annual target exploitation rates for each stock or population that spawns in the river. Second, actions are taken within each fishing season to regulate catches so as to produce the target exploitation. The most difficult monitoring and decision problems are associated with intra-season management; the purpose of this paper is to outline a control system for dealing with these problems

Adaptive Control of Fishing Systems

This paper discusses some formal techniques for deciding how harvesting policies should be modified in the face of uncertainty. Parameter estimation and dynamic optimization methods are combined for the Ricker stock recruitment model to show how exploitation rates should be manipulated to give more information about the model parameters. In general, harvesting rates should be lower than would be predicted by the best fitting recruitment curve unless this curve predicts that the stock is very productive. A decision procedure is developed for comparing alternative stock recruitment models; when applied to the Fraser River sockeye salmon, the procedure indicates that an experimental increase in escapements would be worthwhile. It appears that there is considerable promise for extending these methods and procedures to cases where the stock size is unknown and where fishing effort is poorly controlled

The IIASA Ecology Project: A Status Report

The Ecology Project commenced work in 1973 with the initial and continuing goal of developing a coherent science of ecological management. The products of our research can be divided into three groups: conceptual, applied, and case studies. To give the project focus, we chose to analyze in detail specific regional case studies. Each of these examples has all the ingredients of a large class of problems that together comprise the global problems of resource management for food, fiber, energy, and cultural needs of societies. This report provides an overview of the work of this project through July, 1975, and a summary of our current thinking on future directions and formats of ecological and environmental research at IIASA. The major content of this report is comprised of a description of the case studies which have formed the core of the past two years' efforts

A Predator-Prey Model for Discrete-Time Commercial Fisheries

A very simple discrete-time predator (boats) -- prey (fish) model for the description of the dynamic behavior of a fishery is presented. The stability properties of the system are analyzed in some detail and the sensitivity of the equilibrium with respect to the catchability coefficient, the length of the fishing season and the investment coefficient of the fleet is analyzed. Finally, a simple procedure is presented and used for estimating the characteristic parameters of the fleet of a few fisheries. The agreement between the data and the predicted results is quite satisfactory when considering the crudeness of the model

Cost effectiveness of community leg ulcer clinics: randomised controlled trial

Objectives: To establish the relative cost effectiveness of community leg ulcer clinics that use four layer compression bandaging versus usual care provided by district nurses. Design: Randomised controlled trial with 1 year of follow up. Setting: Eight community based research clinics in four trusts in Trent. Subjects: 233 patients with venous leg ulcers allocated at random to intervention (120) or control (113) group. Interventions: Weekly treatment with four layer bandaging in a leg ulcer clinic (clinic group) or usual care at home by the district nursing service (control group). Main outcome measures: Time to complete ulcer healing, patient health status, and recurrence of ulcers. Satisfaction with care, use of services, and personal costs were also monitored. Results: The ulcers of patients in the clinic group tended to heal sooner than those in the control group over the whole 12 month follow up (log rank P=0.03). At 12 weeks, 34% of patients in the clinic group were healed compared with 24% in the control. The crude initial healing rate of ulcers in intervention compared with control patients was 1.45 (95% confidence interval 1.04 to 2.03). No significant differences were found between the groups in health status. Mean total NHS costs were £878.06 per year for the clinic group and £859.34 for the control (P=0.89). Conclusions: Community based leg ulcer clinics with trained nurses using four layer bandaging is more effective than traditional home based treatment. This benefit is achieved at a small additional cost and could be delivered at reduced cost if certain service configurations were used

Allopurinol use yields potentially beneficial effects on inflammatory indices in those with recent ischemic stroke: a randomized, double-blind, placebo-controlled trial

<p><b>Background and Purpose</b>: Elevated serum uric acid level is associated with poor outcome and increased risk of recurrent events after stroke. The xanthine oxidase inhibitor allopurinol lowers uric acid but also attenuates expression of inflammatory adhesion molecules in murine models, reduces oxidative stress in the vasculature, and improves endothelial function. We sought to investigate whether allopurinol alters expression of inflammatory markers after acute ischemic stroke.</p> <p><b>Methods</b>: We performed a randomized, double-blind, placebo-controlled trial to investigate the safety, tolerability, and effect of 6 weeks’ treatment with high- (300 mg once a day) or low- (100 mg once a day) dose allopurinol on levels of uric acid and circulating inflammatory markers after ischemic stroke.</p> <p><b>Results</b>: We enrolled 50 patients with acute ischemic stroke (17, 17, and 16 in the high, low, and placebo groups, respectively). Mean (±SD) age was 70 (±13) years. Groups had similar characteristics at baseline. There were no serious adverse events. Uric acid levels were significantly reduced at both 7 days and 6 weeks in the high-dose group (by 0.14 mmol/L at 6 weeks, P=0.002). Intercellular adhesion molecule-1 concentration (ng/mL) rose by 51.2 in the placebo group, rose slightly (by 10.6) in the low-dose allopurinol group, but fell in the high-dose group (by 2.6; difference between groups P=0.012, Kruskal-Wallis test).</p> <p><b>Conclusion</b>: Allopurinol treatment is well tolerated and attenuates the rise in intercellular adhesion molecule-1 levels seen after stroke. Uric acid levels were lowered with high doses. These findings support further evaluation of allopurinol as a preventive measure after stroke.</p&gt