The UK's global gas challenge

A UKERC Research Report exploring the UK's global gas challenge. This report takes an interdisciplinary perspective, which marries energy security insights from politics and international relations, with detailed empirical understanding from energy studies and perspectives from economic geography that emphasise the spatial distribution of actors, networks and resource flows that comprise the global gas industry. Natural gas production in the UK peaked in 2000, and in 2004 it became a net importer. A decade later and the UK now imports about half of the natural gas that it consumes. The central thesis of the project on which this report is based is that as the UK’s gas import dependence has grown, it has effectively been ‘globalising’ its gas security; consequently UK consumers are increasingly exposed to events in global gas markets. - See more at: http://www.ukerc.ac.uk/publications/the-uk-s-global-gas-challenge.html#sthash.wEP831Zn.dpu

Variability of the Accretion Stream in the Eclipsing Polar EP Dra

We present the first high time resolution light curves for six eclipses of the magnetic cataclysmic variable EP Dra, taken using the superconducting tunnel junction imager S-Cam2. The system shows a varying eclipse profile between consecutive eclipses over the two nights of observation. We attribute the variable stream eclipse after accretion region ingress to a variation in the amount and location of bright material in the accretion stream. This material creates an accretion curtain as it is threaded by many field lines along the accretion stream trajectory. We identify this as the cause of absorption evident in the light curves when the system is in a high accretion state. We do not see direct evidence in the light curves for an accretion spot on the white dwarf; however, the variation of the stream brightness with the brightness of the rapid decline in flux at eclipse ingress indicates the presence of some form of accretion region. This accretion region is most likely located at high colatitude on the white dwarf surface, forming an arc shape at the foot points of the many field lines channeling the accretion curtain.Comment: Accepted for publication in MNRAS (7 pages

Accretion stream mapping with genetically modified "fire-flies"

We apply an eclipse mapping technique using `genetically modified fire-flies' to the eclipse light curves of HU Aqr and EP Dra. The technique makes as few assumptions as possible about the location of accretion stream material, allowing the emission to be located anywhere within the Roche lobe of the white dwarf. We model two consecutive eclipses in the UBVR_c band for HU Aqr, and four consecutive `white'-light eclipses for EP Dra, to determine the changing brightness distribution of stream material. We find fire-fly distributions which are consistent with accretion through a curtain of material in both HU Aqr and EP Dra, and show that the previously assumed two part ballistic and magnetic trajectory is a good approximation for polars. Model fits to the colour band data of HU Aqr indicate that the material confined to the magnetic field lines is brightest, and most of the emission originates from close to the white dwarf. There is evidence for emission from close to a calculated ballistic stream in both HU Aqr and EP Dra.We propose that a change in the stream density causes a change in the location of the bright material in the accretion stream in EP Dra.Comment: accepted for publication in MNRA

XMM-Newton observations of the eclipsing polar EP Dra

We present XMM-Newton observations of the eclipsing polar EP Dra which cover nearly 3 binary orbital cycles. The X-ray and UV data show evidence for a prominent dip before the eclipse which is due to the accretion stream obscuring the accretion region. The dip ingress is rapid in hard X-rays suggesting there is a highly collimated core of absorption. We find that a different level of absorption column density is required to match the observed count rates in different energy bands. We propose that this is due to the fact that different absorption components should be used to model the reprocessed X-rays, the shocked X-ray component and the UV emission and explore the affect that this has on the resulting fits to the spectrum. Further, there is evidence that absorption starts to obscure the softer X-rays shortly after the onset of the bright phase. This suggests that material is threaded by an unusually wide range of magnetic field lines, consistent with the suggestion of Bridge et al. We find that the period is slightly greater than that determined by Schwope & Mengel.Comment: Accepted for publication MNRAS, 6 page

Navigating the Structural Coherence of Sea Life

Ice breaking by ships can cause irreparable harm to the ecologies and cultures of northern regions. This chapter revolves around a central question: what are the barriers preventing the development of a legal mechanism to limit this act of environmental violence? The chapter suggests that the central barrier is not so much legal as it is ontological: foundational conceptions of space that underpin Western legal institutions are unable to value the form of water, reducing it instead to an ed space that is used for movement or resource extraction. This chapter demonstrates how a consideration of the environmental violence of ice breaking requires us to challenge underlying ideas about the various surfaces, volumes, structures, and movements of ocean-space that are inherent in Western conceptions of mobility, time, and territory. By looking beyond the ocean’s seemingly formless liquidity, this chapter explores how thinking from an oceanic perspective can challenge the limits of law, and how an inquiry that directly interrogates legal norms and institutions can reveal gaps in our understanding and governance of the ocean

Electrospun gelatin-based scaffolds as a novel 3D platform to study the function of contractile smooth muscle cells in vitro

Contractile dysfunction of smooth muscle (SM) is a feature of chronic cardiovascular, respiratory and gastro-intestinal diseases. Owing to the low availability of human ex vivo tissue for the assessment of SM contractile function, the aim of this study was to develop a novel in vitro SM model that possesses the ability to contract, and a method to measure its contractility. A range of electrospun scaffolds were produced from crosslinked gelatin and methacrylated gelatin (GelMA), generating highly aligned scaffolds with average fibre diameters ranging from 200 nm to several micrometres. Young's moduli of the scaffolds ranged from 1x105 to 1x107 Pa. Primary aortic smooth muscle cells (AoSMCs; rat) cells readily adhered to and proliferated on the fibrous scaffolds for up to 10 days. They formed highly aligned populations following the topographical cues of the aligned scaffolds and stained positive for SM markers, indicating a contractile phenotype. Cell-seeded GelMA scaffolds were able, upon stimulation with uridine 5'-triphosphate (UTP), to contract and their attachment to a force transducer allowed the force of contraction to be measured. Hence, these electrospun GelMA fibres can be used as biomimetic scaffolds for SM cell culture and in vitro model development, and enables the contractile forces generated by the aligned three-dimensional sheet of cells to be directly measured. This will supplement in vitro drug screening tools and facilitate discovery of disease mechanisms