The Canadian Component of the Basic Linked System: The Policy Block

The intent of this paper was to examine alternative approaches for incorporating into the Basic Linked System (BLS) model those major policies of a country which influence the world and domestic market price differentials and the level of trade for the ten traded commodities. The study focuses on Canada, but the approach should be applicable to other country models. The main emphasis is on the domestic-international price difference but alternative approaches to quantitative restrictions on trade and stock levels are examined

The Canadian Component of the IIASA World Food Model

Understanding the nature and dimensions of the world food problem and the policies available to alleviate it has been the focal point of IIASA's Food and Agriculture Program (FAP) since it began in 1977. National food systems are highly interdependent, and yet the major policy options exist at the national level. Therefore, to explore these options, it is necessary both to develop policy models for national economies and to link them together by trade and capital transfers. Over the years FAP has, with the help of a network of collaborating institutions, developed and linked national policy models of twenty countries, which together account for nearly 80 percent of important agricultural attributes such as area, production, population, exports, imports and so on. The remaining countries are represented by 14 somewhat simpler models of groups of countries. A separate national model of Canada, which is a major agricultural trader, is included in our system of linked models. Several different approaches to model Canadian agriculture were tried out and compared with the help of Canadian specialists from the University of British Columbia and Agriculture Canada. John Graham, H. Bruce Huff and Ralph G. Lattimore have described these approaches and compared them in this paper. This working paper is one of a series of Working Papers documenting the work that went into developing the various models of FAP's system of linked models

The Physics of Star Cluster Formation and Evolution

© 2020 Springer-Verlag. The final publication is available at Springer via https://doi.org/10.1007/s11214-020-00689-4.Star clusters form in dense, hierarchically collapsing gas clouds. Bulk kinetic energy is transformed to turbulence with stars forming from cores fed by filaments. In the most compact regions, stellar feedback is least effective in removing the gas and stars may form very efficiently. These are also the regions where, in high-mass clusters, ejecta from some kind of high-mass stars are effectively captured during the formation phase of some of the low mass stars and effectively channeled into the latter to form multiple populations. Star formation epochs in star clusters are generally set by gas flows that determine the abundance of gas in the cluster. We argue that there is likely only one star formation epoch after which clusters remain essentially clear of gas by cluster winds. Collisional dynamics is important in this phase leading to core collapse, expansion and eventual dispersion of every cluster. We review recent developments in the field with a focus on theoretical work.Peer reviewe