Nitrogen sources, transport and processing in peri-urban floodplains

Peri-urban floodplains are an important interface between developed land and the aquatic environment and may act as a source or sink for contaminants moving from urban areas towards surface water courses. With increasing pressure from urban development the functioning of floodplains is coming under greater scrutiny. A number of peri-urban sites have been found to be populated with legacy landfills which could potentially cause pollution of adjacent river bodies. Here, a peri-urban floodplain adjoining the city of Oxford, UK, with the River Thames has been investigated over a period of three years through repeated sampling of groundwaters from existing and specially constructed piezometers. A nearby landfill has been found to have imprinted a strong signal on the groundwater with particularly high concentrations of ammonium and generally low concentrations of nitrate and dissolved oxygen. An intensive study of nitrogen dynamics through the use of N-species chemistry, nitrogen isotopes and dissolved nitrous oxide reveals that there is little or no denitrification in the majority of the main landfill plume, and neither is the ammonium significantly retarded by sorption to the aquifer sediments. A simple model has determined the flux of total nitrogen and ammonium from the landfill, through the floodplain and into the river. Over an 8 km reach of the river, which has a number of other legacy landfills, it is estimated that 27.5 tonnes of ammonium may be delivered to the river annually. Although this is a relatively small contribution to the total river nitrogen, it may represent up to 15% of the ammonium loading at the study site and over the length of the reach could increase in-stream concentrations by nearly 40%. Catchment management plans that encompass floodplains in the peri-urban environment need to take into account the likely risk to groundwater and surface water quality that these environments pose

Is the precipitation of anxiety symptoms associated with bolus doses of flumazenil a barrier to its use at low continuous doses in benzodiazepine withdrawal?

Introduction: Benzodiazepines (BZDs) are used in the management of anxiety and sleep disorders; however, chronic use is associated with tolerance and dependence. During withdrawal, symptoms of anxiety are often severe and problematic for patients and may lead to relapse or maintenance on low doses of BZDs. Low, continuous doses of flumazenil reduce BZD withdrawal symptoms in several studies; however, bolus doses are known to induce anxiety and precipitate panic. Accordingly, this study aimed to determine whether continuous low-dose flumazenil is anxiogenic like bolus doses. Method: In a randomised control cross over design, participants received a continuous low-dose flumazenil infusion for eight days at an approximate rate of 4 mg/24 h or placebo before crossing over to the alternate study arm. Participants were able to request diazepam as needed. The primary outcome was the change in state anxiety levels. Trait anxiety was also recorded at baseline and one month after the flumazenil/placebo infusion period. Results: BZD use was significantly reduced in both groups. There were no significant differences between state anxiety and the 95% confidence interval showed no evidence of a clinically significant anxiogenic effect from low-dose flumazenil. Trait anxiety was significantly reduced one month after the infusion period. Conclusion: There is no evidence that continuous low-dose flumazenil infusion significantly increases state anxiety levels to a clinically significant level. Interestingly, flumazenil may decrease state anxiety during BZD withdrawal, unlike bolus doses of flumazenil. Flumazenil may have an anxiolytic effect on trait anxiety, which was evident one month after treatment

Dissolution of metal precipitates in multicrystalline silicon during annealing and the protective effect of phosphorus emitters

The degradation of the carrier lifetime in multicrystalline silicon due to the dissolution of metal precipitates during high temperature annealing is well known. This letter presents evidence indicating that the presence of phosphorus emitters during annealing can help reduce this recontamination. Part of the degradation observed is due to increased interstitial iron concentrations caused by the dissolution of iron precipitates during annealing. However, dissolution of other metals also seems to contribute to the reduced carrier lifetimes observed.The authors would like to acknowledge the Australian Research Council for funding this work

PD-L1 Co-Stimulation Contributes to Ligand-Induced T Cell Receptor Down-Modulation on CD8+CD8^+ T Cells

T cell receptor (TCR) down-modulation after antigen presentation is a fundamental process that regulates TCR signal transduction. Current understanding of this process is that intrinsic TCR/CD28 signal transduction leads to TCR down-modulation. Here, we show that the interaction between programmed cell death 1 ligand 1 (PD-L1) on dendritic cells (DCs) and programmed death 1 (PD-1) on CD8 T cells contributes to ligand-induced TCR down-modulation. We provide evidence that this occurs via Casitas B-lymphoma (Cbl)-b E3 ubiquitin ligase up-regulation in CD8 T cells. Interference with PD-L1/PD-1 signalling markedly inhibits TCR down-modulation leading to hyper-activated, proliferative CD8 T cells as assessed in vitro and in vivo in an arthritis model. PD-L1 silencing accelerates anti-tumour immune responses and strongly potentiates DC anti-tumour capacities, when combined with mitogen-activated kinase (MAPK) modulators that promote DC activation

Land-Use Legacies Are Important Determinants of Lake Eutrophication in the Anthropocene

Background: A hallmark of the latter half of the 20 th century is the widespread, rapid intensification of a variety of anthropogenically-driven environmental changes—a ‘‘Great Acceleration.’ ’ While there is evidence of a Great Acceleration in a variety of factors known to be linked to water quality degradation, such as conversion of land to agriculture and intensification of fertilizer use, it is not known whether there has been a similar acceleration of freshwater eutrophication. Methodology/Principal Findings: Using quantitative reconstructions of diatom-inferred total phosphorus (DI-TP) as a proxy for lake trophic state, we synthesized results from 67 paleolimnological studies from across Europe and North America to evaluate whether most lakes showed a pattern of eutrophication with time and whether this trend was accelerated after 1945 CE, indicative of a Great Acceleration. We found that European lakes have experienced widespread increases in DI-TP over the 20 th century and that 33 % of these lakes show patterns consistent with a post-1945 CE Great Acceleration. In North America, the proportion of lakes that increased in DI-TP over time is much lower and only 9 % exhibited a Great Acceleration of eutrophication. Conclusions/Significance: The longer and more widespread history of anthropogenic influence in Europe, the leading cause for the relatively pervasive freshwater eutrophication, provides an important cautionary tale; our current path of intensive agriculture around the world may lead to an acceleration of eutrophication in downstream lakes that could tak

New constellations of difference in Europe's museumscape

This article addresses some of the recent, ongoing, and planned reconfigurations of museums in Europe in light of their implications for the making of cultural difference, diversity, and citizenship. It argues that these are configured not only through the internal content of particular museums but also through divisions of classificatory labor and hierarchies of value between kinds of museums and their locations within cities and within nations—that is, through constellations of difference within museumscapes. It examines this in relation to examples of planned and realized new museums, including of Europe, national history, and world museums. Particular attention is given here to the fate of ethnographic or ethnological museums—museums that have had especially significant places in the coordination of difference and identity—and to the consequences of this within shifting grounds of belonging and cultural citizenship. The article then discusses some potential consequences of museum configuration within one city by looking at plans for reconfiguring Berlin's museumscape, especially in relation to the Humboldt Forum, in reconstructed facades of a former palace in the center of the urban and national museumscape

Digital museum collections and social media: ethical considerations of ownership and use

This paper examines the role of digital collections and digital information in the democratisation process of museums. The paper focuses on ethical and ownership issues regarding Wikipedia’s online encyclopaedia initiative to widen access to digital images and knowledge through digital media, for the wider public. The paper draws on three cases of national museums in the UK, namely the Victoria and Albert Museum, the British Museum and the National Portrait Gallery. The paper argues that notions of governmentality, power, authority, and control - which traditionally characterise national museums - are still dominant in digital collections. This occasionally results in tensions that revolve around the issue of ownership of digital images and digital museum objects as well as their commercial and non-commercial uses. The paper shows that recent disputes and discourse related to the use of digital images by Wikipedians (active users of Wikipedia) have raised issues of authority and control not only of physical objects but also of the information and knowledge related to these objects. The paper demonstrates that the level of collaboration with Wikipedia reflects to some extent the participatory nature, philosophy, and ideology of each museum institution