Relative importance of transpiration rate and leaf morphological traits for the regulation of leaf temperature

Urban greening solutions such as green roofs help improve residents’ thermal comfort and building insulation. However, not all plants provide the same level of cooling. This is partially due to differences in plant structure and function, including different mechanisms that plants employ to regulate leaf temperature. Ranking of multiple leaf/plant traits involved in the regulation of leaf temperature (and, consequently, plants’ cooling ‘service’) is not well understood. We therefore investigated the relative importance of water loss, leaf colour, thickness and extent of pubescence for the regulation of leaf temperature, in the context of species for semi-extensive green roofs. Leaf temperature were measured with an infrared imaging camera in a range of contrasting genotypes within three plant genera (Heuchera, Salvia and Sempervivum). In three glasshouse experiments (each evaluating three or four genotypes of each genera) we varied water availability to the plants and assessed how leaf temperature altered depending on water loss and specific leaf traits. Greatest reductions in leaf temperature were closely associated with higher water loss. Additionally, in non-succulents (Heuchera, Salvia), lighter leaf colour and longer hair length (on pubescent leaves) both contributed to reduced leaf temperature. However, in succulent Sempervivum, colour/pubescence made no significant contribution; leaf thickness and water loss rate were the key regulating factors. We propose that this can lead to different plant types having significantly different potentials for cooling. We suggest that maintaining transpirational water loss by sustainable irrigation and selecting urban plants with favourable morphological traits is the key to maximising thermal benefits provided by applications such as green roofs.

Electricity derivatives pricing with forward-looking information

In order to increase overall transparency on key operational information, power transmission system operators publish an increasing amount of fundamental data, including forecasts of electricity demand and available capacity. We employ a fundamental model for electricity prices which lends itself well to integrating such forecasts, while retaining ease of implementation and tractability to allow for analytic derivatives pricing formulae. In an extensive futures pricing study, the pricing performance of our model is shown to further improve based on the inclusion of electricity demand and capacity forecasts, thus confirming the general importance of forward-looking information for electricity derivatives pricing. However, we also find that the usefulness of integrating forecast data into the pricing approach is primarily limited to those periods during which electricity prices are highly sensitive to demand or available capacity, whereas the impact is less visible when fuel prices are the primary underlying driver to prices instead.

Environmental and ecological economics in the 21st century: an age adjusted citation analysis of the most influential articles, journals, authors and institutions

We investigate the influence of articles, authors, journals and institutions in the field of environmental and ecological economics. We depart from studies that investigated the literature until 2001 and include a time period that has witnessed an enormous increase of importance in the field. We adjust for the age effect given the huge impact of the year of an article's publication on its influence and we show that this adjustment does make a substantial difference — especially for disaggregated units of analysis with diverse age characteristics such as articles or authors. We analyse 6597 studies on environmental and ecological economics published between 2000 and 2009. We provide rankings of the influential articles, authors, journals and institutions and find that Ecological Economics, Energy Economics and the Journal of Environmental Economics and Management have the most influential articles, they publish very influential authors and their articles are cited most. The University of Maryland, Resources for the Future, the University of East Anglia and the World Bank appear to be the most influential institutions in the field of environmental and ecological economics.

Neo-Gramscianism

Gramscian concepts have been utilized by scholars to analyze and illuminate various aspects of GLOBAL ENVIRONMENTAL GOVERNANCE. A foremost application of neo-Gramscianism to the scholarship on global environmental governance has been in challenging the basic premise of orthodox regime theory that international environmental rule-making is the exclusive preserve of state actors. Gramscian theory is very sensitive to the role and importance of political contestations, accommodations and compromises, which many have noted as the ‘stuff’ of environmental governance. Crucially, while a Gramscian analysis is sensitive to the counter-hegemonic potential of the subordinate class and the ever contested and changing contours of power in a social regime, it does not subscribe to the unlimited possibility of outcome. Given the utility of neo-Gramscian ideas, as demonstrated by the scholarship discussed, it is surprising that the approach has not been deployed more widely in the scholarship on global environmental governance.

Characterisation of microsatellite markers for fig-pollinating wasps in the Pleistodontes imperialis species complex

We characterised a set of nine polymorphic microsatellite loci for Pleistodontes imperialis sp. 1, the pollinator wasp of Port Jackson fig (Ficus rubiginosa) in south-eastern Australia. Characterisation was performed on 30 female individuals collected from a population in Sydney, Australia. The average number of alleles per locus was 7.33, and eight loci were not in Hardy–Weinberg equilibrium. This was expected as fig wasps are known to be highly inbred. A test of genetic differentiation between two natural populations of P. imperialis sp. 1 (Sydney and Newcastle, Australia – some 120 km apart) yielded a very low FST value of 0.012, suggesting considerable gene flow. Bayesian clustering analysis using TESS 2.3.1, which does not assume Hardy–Weinberg equilibrium, however, indicated potential spatial substructuring between the Sydney and Newcastle populations, as well as within the Sydney population. The described loci were also characterised for two other species in the P. imperialis complex: P. imperialis sp. 2 (Townsville, Australia) and P. imperialis sp. 4 (Brisbane, Australia). Seven and six of the nine loci were polymorphic for P. imperialis sp. 2 and P.imperialis sp. 4, respectively.