A review of regional and global estimates of unconventional gas resources

This Research Report assesses the currently available evidence on the size of unconventional gas resources at the regional and global level. Focusing in particular on shale gas, it provides a comprehensive summary and comparison of the estimates that have been produced to date. It also examines the methods by which these resource estimates have been produced the strengths and weaknesses of those methods, the range of uncertainty in the results and the factors that are relevant to their interpretation

Modelling diet composition dynamics among North Sea predatory fish using a length-structured partial ecosystem model

Multispecies fisheries management approaches must take account of the array of trophic interactions within the ecosystem. Studies of the gut contents of fish stocks in the North Sea show decadal changes in diet composition, as might be expected when the relative abundances of prey species change. In this paper we explore the extent to which a simple model of prey consumption deployed within a dynamic multi-species population model is able to capture those changes. We make use of a length-structured partial-ecosystem model (FishSUMS) in which the relative preferences of predators for prey are set by a combination of species weightings and predator-to-prey length ratios. The model allows for diets to evolve over the lifetime of the predator species as well as in response to changes in the available prey. Eleven commercially important North Sea species were included in the model with full length structure, together with other trophic resources represented in less detail. The model was simultaneously tuned to various sources of data, including time series of stock biomass and landings. We show that, despite the simplicity of the representation of the predation process, it is capable of capturing some of the large observed changes in diet in four predator species that were sampled during the Year of the Stomach projects in 1981 and 1991: cod, haddock, whiting and saithe. We also quantify how much of the biomass is lost to the fishery, to predation by explicitly-modelled species, and to unspecified mortality

Distinct expression patterns of ER alpha and ER beta in normal human mammary gland

AIM: Two oestrogen receptors (ERs) have been identified to date—the “classic” ERa and the more recently described ERb. Although much is known about ERa at the mRNA and protein levels, our knowledge of the expression and distribution of ERb protein is much more limited. The aim of this study was to compare the cellular distribution of ERa and ERb in normal human mammary gland. METHODS: Formalin fixed, paraffin wax embedded material was obtained from reduction mammoplasty specimens, normal tissue adjacent to breast tumour, or fibroadenoma. Sections were immunohistochemically stained for ERa, ERb, and the progesterone receptor. The staining pattern for each antibody was evaluated and compared. RESULTS: ERa was restricted to the cell nuclei of epithelial cells lining ducts and lobules. Although ERb was also seen in these cells, additional strong staining was detected specifically in the cell nuclei of myoepithelial cells. Occasional staining was seen in surrounding stromal and endothelial cell nuclei and in lymphocytes. CONCLUSIONS: ER subtypes have distinct distribution patterns in the normal mammary gland. The widespread distribution of ERb suggests that it may be the dominant ER in the mammary gland where it may be acting as a natural suppressor

Analysis of a cyclotron maser instability with application to space and laboratory plasmas

When a beam of electrons moves into an increasing magnetic field, conservation of the magnetic moment results in the formation of a crescent, or horseshoe shaped velocity distribution. The resultant horseshoe shaped velocity distribution has been shown to be unstable with respect to a cyclotron-maser type instability. This instability has been postulated as the mechanism responsible for auroral kilometric radiation and also non-thermal radiation from other astrophysical bodies. In this paper the previous theory, that assumed an infinite uniform plasma, is extended to apply to a bounded cylindrical geometry. This more exact theory in bounded cylindrical geometry is also directly relevant to a laboratory experiment currently being carried out

Global sensitivity analysis of an end-to-end marine ecosystem model of the North Sea : factors affecting the biomass of fish and benthos

Comprehensive analysis of parameter and driver sensitivity is key to establishing the credibility of models of complex systems. This is especially so for models of natural systems where experimental manipulation of the real-world to provide controlled validation data is not possible. Models of marine ecosystems fall into this category, but despite the interest in these models for evaluating the effects of climate change and fishing on nutrient fluxes and the abundances of flora and fauna, none have yet been subjected to global sensitivity analysis. Here we present results of both local ‘one-at-a-time’ (OAT), and variance based global sensitivity analyses (GSA) of the fish and fishery aspects of StrathE2E, an end-to-end (nutrients to birds and mammals) ecosystem model of the North Sea. The sensitivity of the model was examined with respect to internal biological parameters, and external drivers related to climate and human activity. The OAT Morris method was first used to screen for factors most influential on model outputs. The Sobol GSA method was then used to calculate quantitative sensitivity indices. The results indicated that the fish and shellfish components of the model (demersal and pelagic fish, filter/deposit and scavenge/carnivore feeding benthos) were influenced by different sets of factors. Harvesting rates were directly influential on demersal and pelagic fish biomasses. Suspension/deposit feeding benthos were directly sensitive to changes in temperature, while the temperature acted indirectly on pelagic fish through the connectivity between model components of the food web. Biomass conversion efficiency was the most important factor for scavenge/carnivorous feeding benthos. The results indicate the primacy of fishing as the most important process affecting total fish biomass, together with varying responses to environmental factors which may be relevant in the context of climate change. The non-linear responses and parameter interactions identified by the analysis also highlight the necessity to use global rather than local methods for the sensitivity analysis of ecosystem models