Congestion and participation in outdoor recreation: A household production function approach

This paper examines the effects of congestion on recreational behavior within a household production model of consumer behavior. We assume that congestion affects the household's ability to produce constant quality recreational service flows and derive a reduced-form model for participation decisions in remote and developed camping. Empirical estimates of the effects of a congestion measure on the conditional probability of participation as well as on the level of participation are estimated for each activity by the type of trip using information from the 1972 National Recreation Survey. The findings suggest that congestion was most likely to affect the decision to participate and not the level once that decision had been made. While differences in these effects were observed across the activities studied, it is not clear how they should be interpreted since our congestion measure was a proxy variable likely to perform better for remote camping than developed camping.     

CURRENT REFINERY PROBLEMS AND ISSUES IN PETROLEUM IMPORTING DEVELOPING COUNTRIES

This article discusses the problems facing refinery operations in developing countries and possible solutions to them. The topics covered include security of crude oil supply to the developing countries; difficulties encountered in development of indigenous expertise in refinery operation; refinery capacity and the special problems of maintenance and repair facing refinery operators in the developing parts of the world; and the potential for improved refinery operation through increased international co-operation.     

Some epidemiologic features of disasters in guatemala

Epidemiological procedures can be organised under disaster conditions by means of a simple surveillance system and with few personnel.
In the aftermath of the 4 February 1976 earthquake in Guatemala, an information system was organized by which the requisite information for decision-making was obtained with adequate speed and promptness.
The initial epidemiologic informution was based on reports collected during the early days on symptoms observed at hospitals and health centers and in localities and villages in the stricken area.
At a second, post-emergency stage a more elaborate surveillance system was instituted to provide guidance in the investigntwn of outbreaks, evaluate the health activities and establish basic criteria for preventive and control measures.     

Quality control in low-level radionuclide analysis. Results of recent intercomparisons and programmes for 1979/80 of the international atomic energy agency

The results of recent IAEA intercomparison programs are reviewed.     

Threshold and dose response estimation using the “filter model”

The “filter model” has been developed to explain the biologic effects of radiation and chemicals. We have examined nearly 300 sets of dose response data, of which 50 are presented here. Responses (induced by radiation and chemicals) which have been examined include in vitro survival studies on animal and plant tissues, induction of cellular aberrations and time to tumor or death. Similar data from in vivo studies has also been examined. All of the data appear to fit the model R = a lnD + b(lnD)² + c, where R is the response, a and b are parameters fitted by regression to a particular set of data, and c is the response at zero (or lowest) dose. By writing this model in exponential form, it can be seen that the response R results from multistage filtering (by net amounts a and b) of the initial dose, D. The threshold is obtained from this model as the point, $\text{D}\text{?}{}_{\mathrm{T}}$, at which the second derivative becomes zero. This is given by $\text{D}\text{?}{}_{\mathrm{T}}\text{=}\text{exp}\text{(1 ?}\text{a}\text{2b}\text{)}$ when a and b are oppositelt signed.     

NATURAL GAS PROSPECTS IN DEVELOPING COUNTRIES AND THE ROLE OF LNG TRANSPORTATION

Natural gas may provide a major contribution to the world energy supply during the next few decades. The developing countries command about 50 per cent of the world proved natural gas reserves, with gas accounting for only 6 per cent of commercial primary energy production. The challenging task of expanding gas production and utilization in the developing countries, especially through effective use of gas associated with petroleum deposits and transportation of gas in liquefied form (LNG), will require long-term technical co-operation policy commitments with regard to investment, manpower and the transfer of technology. The article is intended to analyse the basic factors involved in these problems. Au cours des prochaines décennies, le gaz naturel peut constituer un apport considérable à l'approvisionnement énergétique mondial. Les pays en développement détiennent approximativement 50 pour cent des réserves mondiales prouvées de gaz naturel, le gaz représentant seulement 6 pour cent de la production d'énergie primaire commerciale. Le défi lancé par la production et l'utilisation croissantes de gaz dans les pays en développement, particulièrement par l'utilisation efficace du gaz lié aux gisements de pétrole et le transport du gaz liquéfié (GNL), requiert des engagements à long terme en matière de politique de coopération technique dans le domaine des investissements, de la main-d'oeuvre et du transfert de technologie. Cet article a pour but d'analyser les facteurs fondamentaux à prendre en considération lorsqu'on traite de ces problèmes. El gas natural podría representar una gran contribucíon a la oferta mundial de energía dentro de las próximas décadas. Los países en desarrollo poseen cerca del 50 porciento de la reserva provada mundial de gas y solamente el 6 porciento de la producción primaria de energía comercial proviene del gas. La tarea de expandir la producción y utilización de gas en los países en desarrollo, especialmente ia utilización efectiva en forma líquida (LNG) de gas asociado al petróleo, requiere de compromisos de cooperación técnica a largo plazo en lo referente a inversiones, recursos humanos y transferencia de tecnología. Este artículo intenta analizar los factores básicos pertinentes a dicha tarea.