Scale of production and choice of technique in the engineering industries in developing countries

This article examines the relationship between scale of production, optimal choice of technique and costs for three engineering industries: nuts and bolts, iron founding and machine tools. In all three industries costs of production fell as the scale of output increased. This was associated with switches of technique and the spread of fixed costs over a larger number of units. The capital-output ratio fell and labour productivity increased with increases in scale while, in most cases, the capital-labour ratio increased. The implications of these findings are briefly discussed.

Parasite diversity, patterns of MHC II variation and olfactory based mate choice in diverging three-spined stickleback ecotypes

Ecological speciation has been the subject of intense research in evolutionary biology but the genetic basis of the actual mechanism driving reproductive isolation has rarely been identified. The extreme polymorphism of the major histocompatibility complex (MHC), probably maintained by parasite-mediated selection, has been proposed as a potential driver of population divergence. We performed an integrative field and experimental study using three-spined stickleback river and lake ecotypes. We characterized their parasite load and variation at MHC class II loci. Fish from lakes and rivers harbor contrasting parasite communities and populations possess different MHC allele pools that could be the result of a combined action of genetic drift and parasite-mediated selection. We show that individual MHC class II diversity varies among populations and is lower in river ecotypes. Our results suggest the action of homogenizing selection within habitat type and diverging selection between habitat types. Finally, reproductive isolation was suggested by experimental evidence: in a flow channel design females preferred assortatively the odor of their sympatric male. This demonstrates the role of olfactory cues in maintaining reproductive isolation between diverging fish ecotypes.

Choice and Welfare Reform: Lone Parents’ Decision Making around Paid Work and Family Life

Welfare-to-work policy in the UK sees ‘choice’ regarding lone parents’ employment decisions increasingly defined in terms of powers of selection between options within active labour market programmes, with constraints on the option of non-market activity progressively tightened. In this paper, we examine the wider choice agenda in public services in relation to lone-parent employment, focusing on the period of welfare reform following the 2007 Freud review of welfare provision. Survey data is used to estimate the extent to which recent policies promoting compulsory job search by youngest dependent child age map onto lone parents' own stated decision-making regarding if and when to enter the labour market. The findings indicate a substantial proportion of lone parents targeted by policy reform currently do not want a job and that their main reported reason is that they are looking after their children. Economically inactive lone mothers also remain more likely to have other chronic employment barriers, which traverse dependent child age categories. Some problems, such as poor health, sickness or disability, are particularly acute among those with older dependent children who are the target of recent activation policy.

Modelling attribute non-attendance in choice experiments for rural landscape valuation

Non-market effects of agriculture are often estimated using discrete choice models from stated preference surveys. In this context we propose two ways of modelling attribute non-attendance. The first involves constraining coefficients to zero in a latent class framework, whereas the second is based on stochastic attribute selection and grounded in Bayesian estimation. Their implications are explored in the context of a stated preference survey designed to value landscapes in Ireland. Taking account of attribute non-attendance with these data improves fit and tends to involve two attributes one of which is likely to be cost, thereby leading to substantive changes in derived welfare estimates.