ON THE ESTIMATION OF DEMAND SYSTEMS WITH LARGE NUMBER OF GOODS: AN APPLICATION TO SOUTH AFRICA HOUSEHOLD FOOD DEMAND

The estimation of large demand systems to investigate the patterns of consumption of households is notoriously difficult. This study develops a modified Almost Ideal Demand System model based on a flexible two-stage budgeting demand modelling framework to examine the effect of estimation procedures (Bottom-up and Top-down) on South African household food consumption parameters. Household food consumption was divided into seven broad food groups: meat and fish; grains; dairy products; fruits; vegetables; other foods. The demand systems were estimated using data from the 1993 South Africa Integrated Household Survey (SIHS) conducted by the South African Labour and Development Research Unit (SALDRU). Empirical results indicate that the Top-down approach is more suited for estimation of South African household food demand. Results indicate that own-price do play an important role in influencing household food consumption. Results also indicate no presence of gross substitution between and within food groups. Expenditure elasticity estimates indicate that meat and fish, dairy products and fruits are luxury products, while grains, vegetables and other foods are necessities in South African household diet.Consumer/Household Economics, Research Methods/ Statistical Methods,

President\u27s Address

Delivered at the Bellingham meeting, August, 1937

The Doctrine of Res Judicata as Applied to the Trial of Criminal Cases

The principle of res judicata as applied to civil litigation is very familiar. Likewise well known in the field of criminal law is the doctrine of former jeopardy It is apparent, however, from an examination of decisions in criminal cases, that aside from the very restricted field of former jeopardy, the application of the general doctrine of res judicata to criminal litigation is not generally appreciated and applied. The doctrine of former jeopardy is of course applicable only where the two offenses are identical, and cannot be invoked if the offenses are distinct, even in cases where the same facts give rise to two or more criminal offenses. With the present tendency to multiply statutory regulations and penalties, there is a consequent increase of scope for the application of res judicata as distinguished from former jeopard

A novel measure of changes in force applied to the Perruchet Effect.

The reaction time (RT) version of the Perruchet Effect demonstrates a concurrent dissociation between RTs to respond and conscious expectancy of the outcome across runs of repeated trials. Consequently, the Perruchet Effect is considered strong evidence for multiple learning processes. This conclusion, however, relies on the RT trend being driven by associative learning rather than, as some have argued, US recency or priming mechanisms. Recent research examining the mechanisms underlying the RT trend do so by examining motor activity associated with the response. With this aim in mind, the current study developed, and assessed the usefulness of, a novel method to measure changes in the amount of force applied to the response button in an RT Perruchet paradigm. The results obtained could not be explained by a single mechanism, but suggest multiple factors underlying the RT version of the Perruchet effect

Effects of Snow and Ice on Waterfowl Distribution in the Central Canadian Arctic Islands

Aerial surveys were conducted in 1974 and 1975 to determine distribution and abundance of waterfowl along the coasts of Somerset, Cornwallis, Little Cornwallis, and Byam Martin islands, Boothia Peninsula, as well as parts of Prince of Wales, Devon, Bathurst, and Melville islands. Waterfowl nested normally in 1975 but were prevented from doing so in 1974 by a late thaw. In 1974, but not in 1975, Barrow Strait was ice free by 1 June. Densities of most species were lower in spring 1975 than in 1974, when inhospitable conditions inland forced the birds to concentrate in coastal areas. In late summer Brant (Branta bernicla) and Oldsquaw (Clangula hyemalis) were more numerous in 1975 than in 1974; Brant left the central High Arctic in midsummer 1974, but the reason for the smaller number of Oldsquaw is not evident. Both Snow Geese (Chen caerulescens) and eiders (Somateria spp.) were more abundant in late summer 1974 than in 1975. Many Snow Geese moved to southeastern Somerset Island and adjacent waters to moult in 1974. In 1975 many eiders and Snow Geese remained at inland locations with their broods. Queens Channel, northern Somerset Island and Bellot Strait were particularly important to waterfowl, irrespective of spring phenology. Melville and Byam Martin islands were used by Brant, and Canada Geese (Branta canadensis) occurred mainly on the Boothia Peninsula. Snow Geese were abundant in both years in southeastern Somerset Island, particularly near Creswell Bay, where both breeding and moulting occurred. Coastal waters of Barrow Strait, Prince Regent Inlet and the Gulf of Boothia were heavily used by Oldsquaw in spring and summer, and Crooked Lake, Prince of Wales Island, was used by many moulting Oldsquaw in both years. Common Eiders (S. mollissima) occurred principally in Queens Channel, Barrow Strait and near Bellot Strait; King Eiders (S. spectabilis) also concentrated in the same areas but were more widely distributed throughout the study area.Key words: Arctic Islands, N.W.T., waterfowl distribution, nonbreeding, aerial surveys, Brant, snow Geese, Oldsquaw, eidersMots clés: îles arctiques, T. N-O., distribution des oiseaux marins, non-accouplement, inventaires aériens, bernache cravant, oie blanche, canard à longue queue, eide

What can Associative Learning do for Driving?

This is the final version of the paper. Available from Cognitive Science Society via the link in this record.To improve road safety, it is important to understand the impact that the contingencies around traffic lights have upon drivers’ behavior. There are formal rules that govern behavior at UK traffic lights (see The Highway Code, 2015), but what does experience of the contingencies do to us? While a green light always cues a go response and a singleton red a stop, the behavior linked to amber is ambiguous; in the presence of red it cues readiness to start, while on its own it cues "preparation" to stop. Could it be that the contingencies between stimuli and responses lead to implicit learning of responses that differ from those suggested by the rules of the road? This study used an incidental go/no-go task in which colored shapes were stochastically predictive of whether a response was required. The stimuli encoded the contingencies between traffic lights and their appropriate responses, for example, stimulus G was a go cue, mimicking the response to a green light. Evidence was found to indicate that G was a go cue, while A (which had the same contingencies as an amber light) was a weak go cue, and that R (a stop cue) was surprisingly responded to as a neutral cue.W.G.N. is supported by an ERSC studentship (ES/J50015X/1)