The use of growth curves in forecasting market development—a review and appraisal

The growth curves suitable for forecasting market development are identified and described. The underlying theoretical basis, if any, for their use is examined, and published examples of their applications are given. Doubt is cast on the value of long-term forecasts derived from growth curves applied to markets for consumables. The problems of choice between competing curves are demonstrated by means of some examples. The requirements that a growth curve should meet in order to be an appropriate forecasting tool are identified and illustrated. Many of the published examples of growth curve use are shown to be vulnerable to criticism under one or more of these criteria.     

Tolerance to the behavioral and hypothermic effects of 1-Δ9-Tetrahydrocannabinol in neonatal chicks

Résumé La tolérance de l'effet du 1-⁹ sur l'activité, sur l'échappement d'un stimulant de chaleur et sur la température du corps a été examinée sur des poussins néonataux. La tolérance s'est produite dans les trois conditions examinées.

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Supported by Medical Research Post-doctoral Fellowship MCR 18 (Canada) and NIMH grant No. MH-17001.     

Cointegration and forecast evaluation: Some lessons from National Institute Forecasts

The recent experience of macroeconomic forecasting in the United Kingdom has prompted renewed interest in the evaluation of economic forecasts. This paper uses cointegration tests to investigate what can be learnt from the forecasts produced by the National Institute of Economic and Social Research (NIESR) over the last two decades. Whilst the forecasts and outturns are found to be cointegrated, there remains evidence of systematic relationships between a number of forecast errors. Our results also fail to reject non-cointegration between different vintages of data, suggesting that considerable care should be exercised in both the choice of realisation data used and in the means by which efficiency is tested.     

Sequence and structure of D-glyceraldehyde 3-phosphate dehydrogenase from Bacillus stearothermophilus.

The glyceraldehyde 3-phosphate dehydogenase holoenzyme of Bacillus stearothermophilus possesses precise 222 symmetry: in this respect it differs from the reported structure of the lobster muscle enzyme. Pairs of active sites are linked through a flexible polypeptide loop which probably mediates the structural changes giving rise to cooperative effects. Three additional salt bridges made by each subunit to others would make a major contribution to thermostability of the tetramer.     

Teaching in tandem-running ants

The ant Temnothorax albipennis uses a technique known as tandem running to lead another ant from the nest to food--with signals between the two ants controlling both the speed and course of the run. Here we analyse the results of this communication and show that tandem running is an example of teaching, to our knowledge the first in a non-human animal, that involves bidirectional feedback between teacher and pupil. This behaviour indicates that it could be the value of information, rather than the constraint of brain size, that has influenced the evolution of teaching.