River metamorphosis and environmental change in the Macdonald Valley,New South Wales,since 1949

A significant metamorphosis of channel form occurred on the lower Macdonald River between 1949 and 1955; width and width-depth ratio increased and depth, sinuosity and weighted mean per cent silt-clay in the channel perimeter decreased. The channel has remained unstable since 1955, exhibiting frequent variations in bed elevation and a recent period of minor channel contraction followed by slight enlargement. Since 1946 there has been an increase in summer and annual rainfall and an abrupt, upward shift of the annual series flood frequency curve. As a result an increased proportion of the total sediment load of the river is now being transported as bed-material load. The change in sediment load is a result of greater stream competence and the consequent reworking of sandy sediment temporarily stored within the channel as benches. The observed channel changes are a quasi-adjustment to the increased flood and bed-material load discharges.     

THE PUBLIC LIFE OF ECONOMIC INCENTIVES

Many current proposals for policy reform call for the use of economic incentives. The growing application of economic incentives in a number of policy areas necessitates continuing critical examination of the claims for and the criticisms of their use. Early empirical evidence on the implementation of incentive schemes serves to shed light on the validity of some of the supporting and opposing arguments. By continuing the assessment of the viability of economic incentives, this study reveals that incentive alternatives face obstacles to use stemming from implementation problems, but political and philosophical issues pose greater threats. Nevertheless, the use of incentives can best be defended on political and moral grounds. Political resistance can be overcome and incentives can be employed effectively, if incentive schemes are understood as fostering one form of social interaction in a mixed regime.     

REGIONAL AIR CARRIERS IN CANADA: NETWORK EVOLUTION AND GOVERNMENT POLICY

Regional air carriers have grown from localized, smallscale operations in the early 1960s to national operations in the 1980s. Their expansion results from an interplay of technology, route networks, and regulation policy. Government policy on regulation first assigned regions in the 1960s and then, in the 1970s, promoted entry to trunk transcontinental routes. The initial concept of the air transport region must therefore be revised, as the role of the regional carriers now approaches that of the trunk carriers. Regulation remains a key determinant of market share, and deregulation could accelerate the convergence of regional and trunk carriers.
Dans les années soixantes, les lignes aériennes régionales n'entreprenaient que des activités locales, à petite échelle. Présentement, ces měmes lignes fonctionnent, de plus en plus, comme sociétes nationales. L'élargissement de ces lignes provient de l'interaction de plusieurs facteurs, en particulier la technologie, les réseaux aériens et la politique du gouvernement. Cette dernière a permis aux lignes régionales de passer, en 1970, d'un rle local à une présence nationale. Par conséquent, le concept original d'une région aérienne doit ětre revisé, puisque le rle de la ligne régionale s'approche de plus en plus de celui de la société nationale. La part du marché de chaque type de société se détermine par la réglementation imposée par le gouvernement, et la déréglementation pourrait accelerer la convergence des rles des sociétés régionales et nationales.