While previous research found no other variable than corruption to have a negative impact on the growth rate of the elephant populations of African countries, we show that one further significant impact is exerted by "neighbourhood effects". Elephants travel long distances, often crossing borders. Using spatial econometric tools, we find that elephant population changes in one country have a positive ...
We introduce a two-dimensional measure for the heterogeneity of performance within groups. It leads to a much more differentiated description of heterogeneity than alternative measures and it is relatively robust with regard to extreme values of small units ("outliers").
This paper proposes a simultaneous-equation approach to the estimation of the contribution of transport infrastructure accumulation to regional growth. We model explicitly the political-economy process driving infrastructure investments; in doing so, we eliminate a potential source of bias in production-function estimates and generate testable hypotheses on the forces that shape infrastructure policy. ...
The frequency of chromosomal anomalies in spermatozoa appears to increase with male age. Because these anomalies play a role in the etiology of spontaneous abortion, an influence of paternal age on risk of spontaneous abortion is plausible but not established. The aim was to characterize this influence in a prospective study among 5,121 California women, who as members of a prepaid health plan were ...
A new approach in German innovation policy organizes contests of proposals for developing innovation networks. Based on an overview of the different programs, we investigate the advantages and problems of such an approach. We find that this type of policy may have a relatively large impact and can, therefore, be regarded as a rather efficient instrument of innovation policy. Compared to conventional ...
This paper studies data from the wholesale fruit and vegetables market in Marseille. We have details of counteroffers to the prices that were proposed by the seller even when no transaction took place. We analyse the evolution of prices and the relation between the final price struck and the proposals of the two parties. Periods with no buyer refusals, of offers or bargaining with no transaction will ...
