425 research outputs found

    Eruptive shearing of tube pumice: pure and simple

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    Abstract. Understanding the physico-chemical conditions extant and mechanisms operative during explosive volcanism is essential for reliable forecasting and mitigation of volcanic events. Rhyolitic pumices reflect highly vesiculated magma whose bubbles can serve as a strain indicator for inferring the state of stress operative immediately prior to eruptive fragmentation. Obtaining the full kinematic picture reflected in bubble population geometry has been extremely difficult, involving dissection of a small number of delicate samples. The advent of reliable high-resolution tomography has changed this situation radically. Here we demonstrate via the use of tomography how a statistically powerful picture of the shapes and connectivity of thousands of individual bubbles within a single sample of tube pumice emerges. The strain record of tube pumice is dominated by simple shear (not pure shear) in the late deformational history of vesicular magma before eruption. This constraint in turn implies that magma ascent is conditioned by a velocity gradient at the point of origin of tube pumice. Magma ascent accompanied by simple shear should enhance high eruption rates inferred independently for these highly viscous systems. </jats:p

    Complete breeding failures in ivory gull following unusual rainy storms in North Greenland

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    Natural catastrophic events such as heavy rainfall and windstorms may induce drastic decreases in breeding success of animal populations. We report the impacts of summer rainfalls on the reproductive success of ivory gull (Pagophila eburnea) in north-east Greenland. On two occasions, at Amdrup Land in July 2009 and at Station Nord in July 2011, we observed massive ivory gull breeding failures following violent rainfall and windstorms that hit the colonies. In each colony, all of the breeding birds abandoned their eggs or chicks during the storm. Juvenile mortality was close to 100% at Amdrup Land in 2009 and 100% at Station Nord in 2011. Our results show that strong winds associated with heavy rain directly affected the reproductive success of some Arctic bird species. Such extreme weather events may become more common with climate change and represent a new potential factor affecting ivory gull breeding success in the High Arctic

    Serum sclerostin levels in renal cell carcinoma patients with bone metastases

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    Sclerostin has been proposed as a potent inhibitor of bone formation. Sclerostin antibodies are under clinical development to treat osteoporosis and metastatic bone disease. Serum sclerostin level is elevated in multiple myeloma, an osteolytic malignancy, where it might serve as predictive marker for the use of sclerostin-directed antibodies. As renal cell carcinoma (RCC) patients often present with osteolytic metastases, we aimed to investigate serum sclerostin levels in RCC patients. Our study included 53 RCC patients (19 with bone metastases, 25 with visceral metastases and 9 with localized disease) and 53 age- and gender-matched non-osteoporotic controls. Frozen serum samples were subjected to sclerostin quantitative sandwich ELISA. The mean serum sclerostin levels of RCC patients and controls were 45.8 pmol/l and 45.1 pmol/l, respectively (p = 0.86). Analysis of variance showed no difference between the subgroups of RCC patients with regard to visceral or bone metastases or localized disease (p = 0.22). There was no significant association between eGFR (estimated glomerular filtration rate) and serum sclerostin levels in RCC patients (r = 0.05; p = 0.74) and controls (r = 0.06; p = 0.68). Our results indicate that serum sclerostin levels appear not to be a valuable biomarker to assess the occurrence of bone metastases in RCC patients

    Public opinion on energy crops in the landscape: considerations for the expansion of renewable energy from biomass

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    Public attitudes were assessed towards two dedicated biomass crops – Miscanthus and Short Rotation Coppice (SRC), particularly regarding their visual impacts in the landscape. Results are based on responses to photographic and computer-generated images as the crops are still relatively scarce in the landscape. A questionnaire survey indicated little public concern about potential landscape aesthetics but more concern about attendant built infrastructure. Focus group meetings and interviews indicated support for biomass end uses that bring direct benefits to local communities. Questions arise as to how well the imagery used was able to portray the true nature of these tall, dense, perennial plants but based on the responses obtained and given the caveat that there was limited personal experience of the crops, it appears unlikely that wide-scale planting of biomass crops will give rise to substantial public concern in relation to their visual impact in the landscape

    Non-state nations: Structure, rescaling, and the role of territorial policy communities, illustrated by the cases of Wales and Sardinia

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    This paper explores the role of non-state nations’ identity and agency with regard to relations with their host nation states. The particular focus here is on the means by which such regions might express their individuality. To this end, we employ a comparative case study analysis of two non-state nations with a range of differing yet in other ways similar qualities – namely Wales (UK) and Sardinia (Italy). We suggest that this is a valuable exercise, allowing as it does for the exploring of evidence ‘on the ground’ of the processes involved. The conceptual rationale for the paper is provided by new regionalism – regions as actors beyond the nation state. Following this, the idea of the ‘territorial policy community’ is presented as a point of departure, with the scope of the paper being to develop a diachronic framework for regional change. Given the focus on identity and interest articulation, the role of regional political parties is a particular subject of the empirical investigation, with non-state nations and nation states linked by opportunistic relationships based on political and electoral support. We then consider what this might mean with regard to the capacity of non-state nations to build on the past to successfully negotiate future policy-making agendas. Finally, we reflect on the limitations of the study, and consider the implications of its findings for further research agendas

    The Lore of Low Methane Livestock:Co-Producing Technology and Animals for Reduced Climate Change Impact

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    Methane emissions from sheep and cattle production have gained increasing profile in the context of climate change. Policy and scientific research communities have suggested a number of technological approaches to mitigate these emissions. This paper uses the concept of co-production as an analytical framework to understand farmers’ evaluation of a 'good animal’. It examines how technology and sheep and beef cattle are co-produced in the context of concerns about the climate change impact of methane. Drawing on 42 semi-structured interviews, this paper demonstrates that methane emissions are viewed as a natural and integral part of sheep and beef cattle by farmers, rather than as a pollutant. Sheep and beef cattle farmers in the UK are found to be an extremely heterogeneous group that need to be understood in their specific social, environmental and consumer contexts. Some are more amenable to appropriating methane reducing measures than others, but largely because animals are already co-constructed from the natural and the technical for reasons of increased production efficiency

    Valoriser et conserver le pin de Salzmann en France -

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    Cet article fait le point sur l'état des connaissances disponibles sur le pin de Salzmann, dans les domaines écologique, sylvicole et de diversité génétique. Il fait aussi état des risques qui menacent cette ressource française originale, caractéristique de la forêt méditerranéenne et indique quelles sont les stratégies actuelles employées pour sauvegarder et utiliser durablement les populations naturelles

    An optimized derivative of an endogenous CXCR4 antagonist prevents atopic dermatitis and airway inflammation

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    Aberrant CXCR4/CXCL12 signaling is involved in many pathophysiological processes such as cancer and inflammatory diseases. A natural fragment of serum albumin, named EPI-X4, has previously been identified as endogenous peptide antagonist and inverse agonist of CXCR4 and is a promising compound for the development of improved analogues for the therapy of CXCR4-associated diseases. To generate optimized EPI-X4 derivatives we here performed molecular docking analysis to identify key interaction motifs of EPI-X4/CXCR4. Subsequent rational drug design allowed to increase the anti-CXCR4 activity of EPI-X4. The EPI-X4 derivative JM#21 bound CXCR4 and suppressed CXCR4-tropic HIV-1 infection more efficiently than the clinically approved small molecule CXCR4 antagonist AMD3100. EPI-X4 JM#21 did not exert toxic effects in zebrafish embryos and suppressed allergen-induced infiltration of eosinophils and other immune cells into the airways of animals in an asthma mouse model. Moreover, topical administration of the optimized EPI-X4 derivative efficiently prevented inflammation of the skin in a mouse model of atopic dermatitis. Thus, rationally designed EPI-X4 JM#21 is a novel potent antagonist of CXCR4 and the first CXCR4 inhibitor with therapeutic efficacy in atopic dermatitis. Further clinical development of this new class of CXCR4 antagonists for the therapy of atopic dermatitis, asthma and other CXCR4-associated diseases is highly warranted

    A Migratory Divide Among Red-Necked Phalaropes in the Western Palearctic Reveals Contrasting Migration and Wintering Movement Strategies

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    Non-breeding movement strategies of migratory birds may be expected to be flexibly adjusted to the distribution and quality of habitat, but only few studies compare movement strategies between populations using distinct migration routes and wintering areas. In thisour study, individual movement strategies of Rred-necked pPhalaropes Phalaropus lobatus, a long-distance migratory wader using saline waters in the non-breeding period, were studied using light-level geolocators. Results revealed the existence of two populations with distinct migration routes and wintering areas: one breeding in the north-eastern North Atlantic and migrating ca. 10,000 km oversea to the tropical eastern Pacific Ocean and the other breeding in Fennoscandia and Russia migrating ca. 6,000 km – largely over land – to the Arabian Sea (Indian Ocean). In line with our expectations, the transoceanic migration between the North Atlantic and the Pacific was associated with proportionately longer wings, a more even spread of stopovers in autumn and a higher migration speed in spring compared to the migration between Fennoscandian-Russian breeding grounds and the Arabian Sea. In the wintering period, birds wintering in the Pacific were stationaryresided in roughly a singlethe same area, whereas individuals wintering in the Arabian Sea showed individually consistent movementsd extensively between different areas, reflecting differences in spatio-temporal variation in primary productivity between the two wintering areas. Our study is unique in showing how habitat distribution shapes movement strategies over the entire non-breeding period within a species.Peer reviewe
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