Optimal universal and categorical benefits with classification errors and imperfect enforcement

We determine the optimal combination of a universal benefit, B, and categorical benefit, C, for an economy in which individuals differ in both their ability to work – modelled as an exogenous zero quantity constraint on labour supply – and, conditional on being able to work, their productivity at work. C is targeted at those unable to work, and is conditioned in two dimensions: ex-ante an individual must be unable to work to be awarded the benefit , whilst ex-post a recipient must not subsequently work. However, the ex-ante conditionality may be imperfectly enforced due to Type I(false rejection) and Type II (false award) classification errors, whilst, in addition, the ex post conditionality may be imperfectly enforced. If there are no classification errors – and thus no enforcement issues – it is always optimal to set C>0, whilst B=0 only if the benefit budget is sufficiently small. However, when classification errors occur, B=0 only if there are no Type I errors and the benefit budget is sufficiently small, while the conditions under which C>0 depend on the enforcement of the ex-post conditionality. We consider two discrete alternatives. Under No Enforcement C>0 only if the test administering C has some discriminatory power. In addition, social welfare is decreasing in the propensity to make each type of error. However, under Full Enforcement C>0 for all levels of discriminatory power, including that of no discriminatory power. Furthermore, whilst social welfare is decreasing in the propensity to make Type I errors, there are certain conditions under which it is increasing in the propensity to make Type II errors. This implies that there may be conditions under which it would be welfare enhancing to lower the chosen eligibility threshold – supporting the suggestion by Goodin (1985) to “err on the side of kindness”.Postprin

Identification of early molecular markers associated with the mantled phenotype in micropropagated oil palms by subtractive PCR and cDNA array analysis

Tissue culture of oil palm induces somaclonal variation. The main one, known as the mantled abnormality, displays homeotic floral modifications and is associated with a lower oil yield. To detect abnormal cell lines as early as possible during the tissue culture process, studies to identify molecular markers have been carried out. Given the epigenetic nature of the mantled phenotype, differential gene expression has been focused upon rather than genome structure. We investigated gene expression patterns at the transcriptome level for three developmental stages: embryogenic cell suspensions, somatic embryos and leafy shoots. In the first step, the technique of subtractive PCR (SSH) was used to construct six cDNA libraries from variant and normal plant materials allowing enrichment for cDNA corresponding to genes which are up- or down-regulated in association with clonal conformity. In the second step, transcript abundance was monitored by macroarray hybridization. A range of genes altered in their expression in abnormal tissues has been identified and a number of which have been validated by RT-PCR. This approach will provide insights into the biological processes involved in the generation of the mantle phenotype and the identified markers should lead to the development of a clonal conformity test. (Résumé d'auteur

Measuring the effectiveness of anti-cartel interventions : a conceptual framework

This paper develops a model of the birth and death of cartels in the presence of enforcement activities by a Competition Authority (CA). We distinguish three sets of interventions: (a) detecting, prosecuting and penalising cartels; (b) actions that aim to stop cartel activity in the short-term, immediately following successful prosecution; (c) actions that aim to prevent the re-emergence of prosecuted cartels in the longer term. The last two intervention activities have not been analysed in the existing literature. In addition we take account of the structure and toughness of penalties. In this framework the enforcement activity of a CA causes industries in which cartels form to oscillate between periods of competitive pricing and periods of cartel pricing. We determine the impact of CA activity on deterred, impeded, and suffered harm. We derive measures of both the total and the marginal effects on welfare resulting from competition authority interventions and show how these break down into measures of the Direct Effect of interventions (i.e. the effect due to cartel activity being impeded) and two Indirect/Behavioural Effects – on Deterrence and Pricing. Finally, we calibrate the model and estimate the fraction of the harm that CAs remove as well as the magnitude of total and marginal welfare effects of anti-cartel interventions.Publisher PD

El modelo HRV para expansión óptima de redes de transmisión: una aplicación a la red eléctrica de Ontario

This paper presents an application of a mechanism that provides incentives to promote transmission network expansion in the electricity system of the Ontario province. Such a mechanism combines a merchant approach with a regulatory approach. It is based on the rebalancing of a two-part tariff within the framework of a wholesale electricity market with nodal pricing. The expansion of the network is carried out through auctions of financial transmission rights for congested links. The mechanism is tested for a simplified transmission grid with ten interconnected zones, ten nodes, eleven lines and seventy eight generators in the Ontario province. The simulation is carried out for both peak and non-peak scenarios. Considering Laspeyres weights, the results show that that prices converge to the marginal cost of generation, the congestion rent decreases, and the total social welfare increases

A snapshot of the epigenetic mechanisms at work in "mantled" oil palm inflorescences

The "mantled" floral variation of oil palm is similar to floral B-class MADS-box genes mutant phenotypes, since the male organs appear to be converted into female ones. We propose to build upon the previous isolation of the EgDEF1 and EgGLO2 genes in oil palm and to undertake a comprehensive investigation of the epigenetic mechanisms controlling their expression and of their role in the onset and in the maintenance of the "mantled" somaclonal phenotype. We are currently investigating the DNA methylation patterns within the regulating and coding sequences of these genes, as well as the chromatin conformation of the surrounding genomic domains. Although the experiments are still in progress, our preliminary results suggest the existence of a differential epigenetic pattern between true-to-type and "mantled" inflorescences. The implication of this discovery, with respect to the "mantled" abnormality, will be discussed. (Texte intégral

A marker-based strategy for the assessment of epigenetic instability in oil palm

Plant tissues from the mantled somaclonal variant of oil palm have been found to display both large-scale perturbations of genomic methylation levels and sequence-specific DNA methylation pattern changes when compared to their true-to-type counterparts. Concomitantly, several markers showing phenotype-specific transcription patterns have been identified in our group. Some of them are likely to be indicators of the altered physiological state of abnormal cultures, others are possible targets of epigenetic misregulations of flower development. We now aim to establish the exact link between the expression of these candidate marker genes and the mantled somaclonal variation state, through the exploration of their global epigenetic behaviour. This will be achieved using three complementary approaches applied to normal and abnormal tissues: i) the evaluation of transcription levels through quantitative or semi-quantitative techniques (semi-quantitative RT-PCR, real-time PCR); ii) the determination of sequence-wide DNA methylation patterns (bisulfite sequencing) and iii) the identification of the chromatin regulatory environment of these genes (Chromatin Immuno-Precipitation: ChIP). These combined strategies will ultimately help to elucidate the epigenetic mechanisms which give rise to the mantled somaclonal variant. Also, we will be able to identify which of the candidate markers which are indeed consistently linked with the abnormal state. This work will provide the basis for a molecular detection test of the variant phenotype. (Résumé d'auteur