Impact of earthworms on trace element solubility in contaminated mine soils amended with green waste compost

The common practice of remediating metal contaminated mine soils with compost can reduce metal mobility and promote revegetation, but the effect of introduced or colonising earthworms on metal solubility is largely unknown. We amended soils from an As/Cu (1150 mgAs kg−1 and 362 mgCu kg−1) and Pb/Zn mine (4550 mgPb kg−1 and 908 mgZn kg−1) with 0, 5, 10, 15 and 20% compost and then introduced Lumbricus terrestris. Porewater was sampled and soil extracted with water to determine trace element solubility, pH and soluble organic carbon. Compost reduced Cu, Pb and Zn, but increased As solubility. Earthworms decreased water soluble Cu and As but increased Pb and Zn in porewater. The effect of the earthworms decreased with increasing compost amendment. The impact of the compost and the earthworms on metal solubility is explained by their effect on pH and soluble organic carbon and the environmental chemistry of each element.

Changes in race-specific virulence in pseudomonas syringae pv. phaseolicola are Associated with a chimeric transposable element and rare deletion events in a plasmid-borne pathogenicity island

Virulence for bean and soybean is determined by effector genes in a plasmid-borne pathogenicity island (PAI) in race 7 strain 1449B of Pseudomonas syringae pv. phaseolicola. One of the effector genes, avrPphF, confers either pathogenicity, virulence, or avirulence depending on the plant host and is absent from races 2, 3, 4, 6, and 8 of this pathogen. Analysis of cosmid clones and comparison of DNA sequences showed that the absence of avrPphF from strain 1448A is due to deletion of a continuous 9.5-kb fragment. The remainder of the PAI is well conserved in strains 1448A and 1449B. The left junction of the deleted region consists of a chimeric transposable element generated from the fusion of homologs of IS1492 from Pseudomonas putida and IS1090 from Ralstonia eutropha. The borders of the deletion were conserved in 66 P. syringae pv. phaseolicola strains isolated in different countries and representing the five races lacking avrPphF. However, six strains isolated in Spain had a 10.5-kb deletion that extended 1 kb further from the right junction. The perfect conservation of the 28-nucleotide right repeat of the IS1090 homolog in the two deletion types and in the other 47 insertions of the IS1090 homolog in the 1448A genome strongly suggests that the avrPphF deletions were mediated by the activity of the chimeric mobile element. Our data strongly support a clonal origin for the races of P. syringae pv. phaseolicola lacking avrPphF.

The management of positive inter-store externalities in shopping centres: some empirical evidence

In enclosed shopping centres, stores benefit from the positive externalities of other stores in the centre. Some stores provide greater benefits to their neighbours than others – for example anchor tenants and brand leading stores. In managing shopping centres, these positive externalities might be captured through rental variations. This paper explores the determinants of rent – including externalities – for UK regional shopping centres. Two linked databases were utilised in the research. One contains characteristics of 148 shopping centres; the other has some 1,930 individual tenant records including rent level. These data were analysed to provide information on the characteristics of centres and retailers that help determine rent. Factors influencing tenant rents include market potential factors derived from urban and regional economic theory and shopping centre characteristics identified in prior retail research. The model also includes variables that proxy for the interaction between tenants and the impact of positive in-centre externalities. We find that store size is significantly and negatively related to tenant with both anchor and other larger tenants, perhaps as a result of the positive effects generated by their presence, paying relatively lower rents while smaller stores, benefiting from the generation of demand, pay relatively higher rents. Brand leader tenants pay lower rents than other tenants within individual retail categories.

Redefining the outer boundaries of EU Law: the Zambrano, McCarthy and Dereci trilogy

In its three recent rulings in the cases of Zambrano, McCarthy, and Dereci, the Court appears to have been determined to redefine the external boundaries of EU law, in cases involving the family reunification rights of Union citizens.These three judgments can be read as an indication that for Article 20 TFEU to apply, there is no longer a requirement of a cross-border element on the facts of the case, and that it is sufficient if the contested national measure has the effect of ‘depriving citizens of the Union of the genuine enjoyment of the substance’ of their rights (the ‘Zambrano principle’).The cases can, at the same time, also be read as a confirmation that the free movement provisions do – still – require a cross-border element and, in particular, the exercise of inter-State movement, in order to apply. Though the result in these cases has not been entirely unexpected, especially in the aftermath of the Rottmann ruling, it is rather problematic in that, although it is obvious that the Court wishes to redraw the line dividing the national and EU spheres of competence, it does not make it entirely clear where this line now lies and leaves many essential questions unanswered, which will obviously require some time to be resolved. EU lawyers are consequently, once more, left with having to decipher as best as they can the real intentions of the Court in this new line of case-law, which has been further complicated by the fact that what the Court seems to have given with one hand in Zambrano (and before that in Rottmann), has taken it back to a large extent through its rulings in McCarthy and Dereci, which appear to confine the former two cases to their own exceptional facts.6 Moreover, the ‘reverse discrimination Pandora’s box’, the opening of which appears to have been the real target of these references, remains untouched: instead of providing a direct solution to this problem, the Court has chosen to – once again – broaden the scope of the Treaty provisions in order to include within it as many situations as possible and, thus, prevent the emergence of this type of differential treatment on a case-by-case basis.As will be explained, nonetheless, this is by no means an appropriate solution to the reverse discrimination conundrum.