The Market for Guayule Rubber

In 1980, IIASA joined with the Centro de Investigacion en Quimica Aplicada (CIQA) to study resource development alternatives for arid and semi-arid regions. This joint effort is motivated by the perception that planning and programming of development projects, as they typically are applied to projects for drylands, are inadequate and pose serious obstacles to successful development of these regions. Two characteristics distinguish the problem of planning and programming development projects for drylands. First, all of the common difficulties that beset development planning and programming (e.g., inadequate data, importance of poorly understood social and cultural relations, inadequate infrastructure, inadequate organizational capacity) are present in the extreme. Second, even very modest-sized development projects are usually enormous in relation to the social, economic, and technical structure of drylands regions; their ramifications are little short of revolutionary. To focus our efforts to improve planning and programming methodologies for dryland regions, it was decided to examine a specific problem: the prospects for developing a dryland region in northern Mexico based on the exploitation of 6 vegetal resources native to the region. A description of this effort is available in: Anderson, R.J., E. Campos-Lopez, and D. Gourmelon. An Analysis of Renewable Resource Development Alternatives for the Northern Arid Region of Mexico: Study Prospectus. WP-81-7. International Institute for Applied Systems Analysis. (January, 1981). Guayule (parthenium argentatum gray) is one of the vegetal resources under investigation in this study. Guayule shrub, which grows wild on the sierras of the Chihuahuan desert, produces a high molecular weight hydrocarbon that can be processed into a premium-quality rubber. For approximately 50 years during the first half of this century a small but important guayule rubber industry operated in Mexico. The Mexican government currently plans to reactivate the guayule rubber industry using shrub harvested from wildstands as the basic source of shrub. This paper examines a critical aspect of this plan, the future market conditions under which a guayule rubber industry would operate. In subsequent papers, projected demand conditions will be compared to information concerning probable production costs to determine whether guayule rubber production is feasible economically

Uncertainty and the Choice of Policy Instruments for Meeting an Environmental Quality Standard

Broadly stated, there are three steps in environmental quality management. These are (1) selection of environmental quality standards, (2) determination of feasible programs for reducing discharges to the environment or for increasing its assimilative capacities, and (3) implementation of a policy to bring about discharge reductions and/or expansion of assimilative capacity. Much of REN's research program has been devoted to state-of-the-art analysis of the effects of discharges on environmental systems and modifications in environmental systems that could be made to enhance systems' abilities to assimilate discharges. For example, case studies of Lake Balaton in Hungary and Attersee and Neusiedlersee in Austria have advanced the state of the art of modeling water quality and are providing a menu of feasible programs for managing the quality of these lakes. Subsequent REN studies will build on these modeling efforts to evaluate alternative management plans and policies. This working paper is the first of a series of reports that are planned to result from these efforts. It considers the problem of choosing a policy instrument (i.e. a means to implement environmental quality standards) that is both effective (i.e. will result in the environmental quality standard being met) and efficient (i.e. will meet standard at least cost). Three alternative policy instruments are considered. These are (1) emission standards, which prescribe maximum allowable rates of discharges of pollutants to the environment, (2) emission charges, which prescribe payments that emitters must make per unit of pollution discharged to the environment, and (3) transferable emission permits, which entitle their holder to a face value quantity of emissions, and which may be transferred among emitters. REN's analyses of specific environmental management problems dramatically illustrate that uncertainty pervades the modeling and management process. Until recently, this fact of the modeling and management problem (i.e. uncertainty) was largely ignored in studies of the policy instrument question. This paper builds on the recent literature to show how, in the presence of uncertainty, policy might best be fashioned to meet an environmental quality standard efficiently

Estimation of the Mass Density of Guayule from Height Data

In 1980, IIASA joined with the Centro de Investigacion en Quimica Aplicada (CIQA) to study resource development alternatives for arid and semi-arid regions. This joint effort is motivated by the perception that planning and programming of development projects, as they typically are applied to projects for drylands, are inadequate and pose serious obstacles to successful development of these regions. Two characteristics distinguish the problem of planning and programming development projects for drylands. First, all of the common difficulties that beset development planning and programming (e.g., inadequate data, importance of poorly understood social and cultural relations, inadequate infrastructure, inadequate organizational capacity) are present in the extreme. Second, even very modest-sized development projects are usually enormous in relation to the social, economic, and technical structure of drylands regions; their ramifications are little short of revolutionary. To focus our efforts to improve planning and programming methodologies for dryland regions, it was decided to examine a specific problem: the prospects for developing a region in northern Mexico based on the exploitation of 6 vegetal resources native to the region. A description of this study is available in: Anderson, R.J., E. Campos-Lopez, and D. Gourmelon. An Analysis of Renewable Resource Development Alternatives for the Northern Arid Region of Mexico: Study Prospectus. WP-81-7. International Institute for Applied Systems Analysis. (January, 1981). Guayule (parthenium argentatum gray) is one of the vegetal resources under investigation in this study. Guayule shrub, which grows wild on the sierras of the Chihuahuan desert, produces a high molecular weight hydrocarbon that can be processed into a premium-quality natural rubber. For approximately 50 years during the first half of this century a small but important guayule rubber industry operated in Mexico. The Mexican government currently plans to reactivate the guayule rubber industry using shrub harvested from wildstands as the basic source of shrub. This paper examines a critical aspect of this plan, the inventory of guayule shrub available for harvest. More specifically, the paper examines a new shrub inventory technique that has been proposed, and attempts to account for differences between the results obtained when this technique is used in place of standard inventory methods

An Estimate of the Maximum Sustainable Yield from Harvest of Guayule Wildstands in the Vicinity of Cedros

In 1980, IIASA joined together with the Centro de Investigacion en Quimica Aplicada (CIQA) to study resource development alternatives for arid and semi-arid regions. This joint effort is motivated by the perception that planning and programming of development projects, as they typically are applied to projects for drylands, are inadequate and pose serious obstacles to successful development of these regions. Two characteristics distinguish the problem of planning and programming development projects for drylands. First, all of the common difficulties that beset development planning and programming (e.g., inadequate data, importance of poorly understood social and cultural relations, inadequate infrastructure, inadequate organizational capacity) are present in the extreme. Second, even very modest-sized development projects are usually enormous in relation to the social, economic, and technical structure of drylands regions; their ramifications are little short of revolutionary. To focus our efforts to improve planning and programming methodologies for dryland regions, it was decided to examine a specific problem: the prospects for developing a dryland region in northern Mexico based on the exploitation of 6 vegetal resources native to the region. A description of this effort is available in: Anderson, R.J., E. Campos-Lopez, and D. Gourmelon. An Analysis of Renewable Resource Development Alternatives for the Northern Arid Region of Mexico: Study Prospectus. WP-81-7. International Institute for Applied Systems Analysis. (January, 1981). Guayule (parthenium argentatum gray) is one of the vegetal resources under investigation in this study. Guayule shrub, which grows wild on the sierras of the Chihuahuan desert, produces a high molecular weight hydrocarbon that can be processed into a premium-quality natural rubber. For approximately 50 years during the first half of this century a small but important guayule rubber industry operated in Mexico. The Mexican government currently plans to reactivate the guayule rubber industry using shrub harvested from wildstands as the basic source of shrub. This paper examines a critical aspect of this plan, the limits on the amount of shrub that can be harvested without exhaustion of the wildstands and without reforestation or other forestry management methods

The Probability Distribution of Water Inputs and the Economic Benefits of Supplementary Irrigation

Several of REN's studies have examined the effect of risk and uncertainty on the status and management of environmental resources. This paper examines some of the effects of risk and uncertainty on the economics of production processes that depend upon randomly-varying environmental resource inputs. Work on this topic is continuing in the context of REN's studies in its Regional Water Management, Ecological Modeling, and Climate tasks

An Economic Analysis of Supplementary Irrigation in Skane

This report analyzes the water demand for supplementary irrigation in Skane. It attempts to answer questions raised by previous IIASA studies: what is the potential demand for irrigation water at current crop prices and irrigation costs; what effect would this have on the crop market, and how would the changed market subsequently effect the demand for irrigation; and what effect would a significant increase in the cost of irrigation have on the quantity of water used. The studies are based on table potatoes and sugar beets. The analysis shows that irrigation demands may be as great as those calculated using simple water balance models, and that the potential water supply and demand could become seriously out of balance. It is also shown that irrigation would have little effect on the crop market, and water would be required to be reallocated. Finally, it is shown that if farmers were charged the opportunity cost of the water resources they used, supply and demand could be brought back into balance. The report concludes that agricultural demand is an important, possibly the critical, factor in future planning and management of the water supply system in this region

An Analysis of Renewable Resource Development Alternatives for the Northern Arid Region of Mexico: Study Prospectus

In 1980, IIASA joined with the Centro de Investigation en Quimica Aplicada (CIQA) in order to study alternative production chains based on the renewable resources of the Northern Arid Region of Mexico. This study applied the "WELMM Approach" developed at IIASA. Its objective was to account for the basic resources used and processed along alternative production chains, from cultivation and harvesting of the plants to the final products. WELMM analyses of each of the production chains are now being completed, and IIASA and CIQA have decided to expand their cooperative efforts to include an analysis of alternative development projects for the Northern Arid Region based on these production chains. This paper presents a prospectus for the expanded study

Natural Resources and Development in Arid Regions

Forestry and the forestry industry are facing major structural changes. On the production side, the development of processing technology has made the industrial use of wood possible in many new areas; at the same time, wood growing has reached its economic and institutional limits in some old forest areas. As a consequence, a major shift in the global pattern of the supply of wood raw material is taking place. Over the long term, the consumption pattern of forest products is changing: for traditional products, some countries are reaching saturation level whilst in others a considerable increase in demand is anticipated, and technological innovations are changing the overall demand for different products. These issues pose problems that require a global analysis. This book, based on the First North American Conference, includes many impressive state-of-the-art papers in terms of current knowledge and econometric models; it covers modelling the forest products industry with emphasis on international trade, and represents an important step in improving the ability to model forest management investment. Part I introduces the Forest Sector Project of IIASA; Part II presents approaches to developing forest sector models; Part III emphasises some of the sub-problems in model development, specifically on the development of realistic long-term supply response estimation capabilities; Part IV covers approaches to modelling demand and international trade components

First principles electronic structure of spinel LiCr2O4: A possible half-metal?

We have employed first-principles electronic structure calculations to examine the hypothetical (but plausible) oxide spinel, LiCr2O4 with the d^{2.5} electronic configuration. The cell (cubic) and internal (oxygen position) structural parameters have been obtained for this compound through structural relaxation in the first-principles framework. Within the one-electron band picture, we find that LiCr2O4 is magnetic, and a candidate half-metal. The electronic structure is substantially different from the closely related and well known rutile half-metal CrO2. In particular, we find a smaller conduction band width in the spinel compound, perhaps as a result of the distinct topology of the spinel crystal structure, and the reduced oxidation state. The magnetism and half-metallicity of LiCr2O4 has been mapped in the parameter space of its cubic crystal structure. Comparisons with superconducting LiTi2O4 (d^{0.5}), heavy-fermion LiV2O4 (d^{1.5}) and charge-ordering LiMn2O4 (d^{3.5}) suggest the effectiveness of a nearly-rigid band picture involving simple shifts of the position of E_F in these very different materials. Comparisons are also made with the electronic structure of ZnV2O4 (d^{2}), a correlated insulator that undergoes a structural and antiferromagnetic phase transition.Comment: 9 pages, 7 Figures, version as published in PR

Universally Coupled Massive Gravity, II: Densitized Tetrad and Cotetrad Theories

Einstein's equations in a tetrad formulation are derived from a linear theory in flat spacetime with an asymmetric potential using free field gauge invariance, local Lorentz invariance and universal coupling. The gravitational potential can be either covariant or contravariant and of almost any density weight. These results are adapted to produce universally coupled massive variants of Einstein's equations, yielding two one-parameter families of distinct theories with spin 2 and spin 0. The theories derived, upon fixing the local Lorentz gauge freedom, are seen to be a subset of those found by Ogievetsky and Polubarinov some time ago using a spin limitation principle. In view of the stability question for massive gravities, the proven non-necessity of positive energy for stability in applied mathematics in some contexts is recalled. Massive tetrad gravities permit the mass of the spin 0 to be heavier than that of the spin 2, as well as lighter than or equal to it, and so provide phenomenological flexibility that might be of astrophysical or cosmological use.Comment: 2 figures. Forthcoming in General Relativity and Gravitatio