Ground-based detection of a cloud of methanol from Enceladus: When is a biomarker not a biomarker?

Saturn's moon Enceladus has vents emerging from a sub-surface ocean, offering unique probes into the liquid environment. These vents drain into the larger neutral torus in orbit around Saturn. We present a methanol (CH3OH) detection observed with IRAM 30-m from 2008 along the line-of-sight through Saturn's E-ring. Additionally, we also present supporting observations from the Herschel public archive of water (ortho-H2O; 1669.9 GHz) from 2012 at a similar elongation and line-of-sight. The CH3OH 5(1,1)-4(1,1) transition was detected at 5.9 sigma confidence. The line has 0.43 km/s width and is offset by +8.1 km/s in the moon's reference frame. Radiative transfer models allow for gas cloud dimensions from 1750 km up to the telescope beam diameter ~73000 km. Taking into account the CH3OH lifetime against solar photodissociation and the redshifted line velocity, there are two possible explanations for the CH3OH emission: methanol is primarily a secondary product of chemical interactions within the neutral torus that (1) spreads outward throughout the E-ring or (2) originates from a compact, confined gas cloud lagging Enceladus by several km/s. We find either scenario to be consistent with significant redshifted H2O emission (4 sigma) measured from the Herschel public archive. The measured CH3OH:H2O abundance (> 0.5 per cent) significantly exceeds the observed abundance in the direct vicinity of the vents (~0.01 per cent), suggesting CH3OH is likely chemically processed within the gas cloud with methane (CH4) as its parent species.Comment: 16 pages, 4 figures, accepted for publication in the International Journal of Astrobiology (IJA

The Removal of Artificially Generated Polarization in SHARP Maps

We characterize the problem of artificial polarization for the Submillimeter High Angular Resolution Polarimeter (SHARP) through the use of simulated data and observations made at the Caltech Submillimeter Observatory (CSO). These erroneous, artificial polarization signals are introduced into the data through misalignments in the bolometer sub-arrays plus pointing drifts present during the data-taking procedure. An algorithm is outlined here to address this problem and correct for it, provided that one can measure the degree of the sub-array misalignments and telescope pointing drifts. Tests involving simulated sources of Gaussian intensity profile indicate that the level of introduced artificial polarization is highly dependent upon the angular size of the source. Despite this, the correction algorithm is effective at removing up to 60% of the artificial polarization during these tests. The analysis of Jupiter data taken in January 2006 and February 2007 indicates a mean polarization of 1.44%+/-0.04% and 0.95%+/-0.09%, respectively. The application of the correction algorithm yields mean reductions in the polarization of approximately 0.15% and 0.03% for the 2006 and 2007 data sets, respectively.Comment: 19 pages, 7 figure

IDWG, salt and water – an audit of dialysis staff. British Journal of Renal Medicine.

Our haemodialysis service comprises two teaching hospital-based centres and six satellite units, which merged some years ago. The teaching hospitals were traditionally managed by separate groups of dietitians and dialysis staff. Consequently, there were differences in practice within the service, including the methods used to determine an acceptable interdialytic weight gain (IDWG). High IDWG is regarded as a negative factor due to associated intradialytic hypotension, interdialytic hypertension and cardiovascular disease.1 As such, patients with excessive IDWG are frequently advised to limit their daily fluid intake and may be encouraged to reduce their salt intake because of the association between salt intake and thirst.2 Different members of the multidisciplinary team (MDT) act as advisors in this area. This may lead to confusion and non-compliance if the information is conflicting or provided in a negative manner.3 We undertook an audit throughout the haemodialysis service to standardise the advice given to patients. This article reports the results of a questionnaire used to determine how staff respond to excessive IDWG. It also examined their knowledge of the salt and fluid content of common foods

Very High Angular Resolution Science with the Square Kilometre Array

Preliminary specifications for the Square Kilometre Array (SKA) call for 25% of the total collecting area of the dish array to be located at distances greater than 180 km from the core, with a maximum baseline of at least 3000 km. The array will provide angular resolution ~ 40 - 2 mas at 0.5 - 10 GHz with image sensitivity reaching < 50 nJy/beam in an 8 hour integration with 500 MHz bandwidth. Given these specifications, the high angular resolution component of the SKA will be capable of detecting brightness temperatures < 200 K with milliarcsecond-scale angular resolution. The aim of this article is to bring together in one place a discussion of the broad range of new and important high angular resolution science that will be enabled by the SKA, and in doing so, address the merits of long baselines as part of the SKA. We highlight the fact that high angular resolution requiring baselines greater than 1000 km provides a rich science case with projects from many areas of astrophysics, including important contributions to key SKA science.Comment: 13 pages, 6 figure

Johrei Family Healing: A Pilot Study

Johrei is a form of spiritual healing comprising “energy channelling” and light massage given either by a trained healer or, after some basic training, by anyone. This pilot trial aimed to identify any potential benefits of family-based Johrei practice in childhood eczema and for general health and to establish the feasibility of a subsequent randomised controlled trial. Volunteer families of 3-5 individuals, including at least one child with eczema were recruited to an uncontrolled pilot trial lasting 12 months. Parents were trained in Johrei healing and then practised at home with their family. Participants kept diaries and provided questionnaire data at baseline, 3,6 and 12 months. Eczema symptoms were scored at the same intervals. Scepticism about Johrei is presently an obstacle to recruitment and retention of a representative sample in a clinical trial, and to its potential use in general practice. The frequency and quality of practise at home by families may be insufficient to bring about the putative health benefits. Initial improvements in eczema symptoms and diary recorded illness, could not be separated from seasonal factors and other potential confounders. There were no improvements on other outcomes measuring general health and psychological wellbeing of family members

Consequences of fish for cladoceran, water beetle and macrophyte communities in a farmland pond landscape: implications for conservation

Traditionally, fish have been neglected in pond ecology and conservation studies and it has frequently been assumed that they have a detrimental impact on pond biodiversity and ecosystem function. In order to assess the consequences of fish for pond biodiversity and ecosystem structure we sampled a set of 40 small farmland ponds (20 with and 20 without fish) in eastern England and compared their water chemistry as well as assemblage characteristics (abundance, diversity, species composition) for three biological groups: cladocerans (zooplankton), water beetles and macrophytes. Water depth was significantly greater in fish ponds, while pond bottom oxygen levels and pH were significantly higher in the ponds without fish. The presence of fish significantly reduced the abundance of macrophytes and altered the community composition of cladocerans and macrophytes, but had no detectable influence on water beetles. Variation partitioning using environmental and spatial variables, indicated that all three biological groups were spatially structured. The inclusion of fish, however, reduced the importance attributed to space in the case of both cladocerans and macrophytes, suggesting that space effects for these two groups were at least partly the result of a spatially structured predator (i.e.fish). In most cases fish did not have an effect on cladoceran and water beetle alpha diversity (number of species, Shannon's and Simpson's index), although the opposite was true for macrophytes. Nevertheless, at the landscape level, gamma diversity (i.e.total number of species) was enhanced for all three biological groups. Our results suggest that fish, at least small, typical, pond-associated species, are an important component of heterogeneity in farmland pond networks, thereby increasing landscape-scale diversity across several faunal and floral elements. Consequently, we propose that fish should be more fully included in future pond biodiversity surveys and conservation strategies

Time-Splitting Coupling of WaveDyn with OpenFOAM by Fidelity Limit Identified from a WEC in Extreme Waves

Survivability assessment is the complexity compromising Wave energy development. The present study develops a hybrid model aiming to reduce computational power while maintaining accuracy for survivability assessment of a Point-Absorber (PA) Wave Energy Converter (WEC) in extreme Wave Structure Interaction (WSI). This method couples the fast inviscid linear potential flow time-domain model WaveDyn (1.2, DNV-GL, Bristol, UK) with the fully nonlinear viscous Navier&ndash;Stokes Computational Fluid Dynamics (CFD) code OpenFOAM (4.2, OpenFOAM.org, London, UK). The coupling technique enables the simulation to change between codes, depending on an indicator relating to wave steepness identified as a function of the confidence in the linear model solution. During the CFD part of the simulation, the OpenFOAM solution is returned to WaveDyn via an additional load term, thus including viscous effects. Developments ensure a satisfactory initialisation of CFD simulation to be achieved from a &lsquo;hot-start&rsquo; time, where the wave-field is developed and the device is in motion. The coupled model successfully overcomes identified inaccuracies in the WaveDyn code due to the inviscid assumption and the high computational cost of the OpenFOAM code. Experimental data of a PA response under extreme deterministic events (NewWave) are used to assess WaveDyn&rsquo;s validity limit as a function of wave steepness, in order to validate CFD code and develop the coupling. The hybrid code demonstrates the applicability of WaveDyn validity limit and shows promising results for long irregular sea-state applications

Effect of He-appm/DPA ratio on the damage microstructure of tungsten

In-situ ion irradiation and transmission electron microscopy has been used to examine the effects of the He appm to DPA ratio, temperature and dose on the damage structure of tungsten (W). Irradiations were performed with 15 or 60 keV He+ ions, achieving He-appm/displacements per atom (DPA) ratios of ~40,000 and ~2000, respectively, at temperatures between 500 and 1000°C to a dose of ~3 DPA. A high number of small dislocation loops with sizes around 5–20 nm and a He bubble lattice were observed for both He-appm/DPA ratios at 500°C with a bubble size ~1.5 nm. Using the g.b=0 criterion the loops were characterised as b = ±1/2 type. At 750°C bubbles do not form an ordered array and are larger in size compared to the irradiations at 500°C, with a diameter of ~3 nm. Fewer dislocation loops were observed at this temperature and were also characterised to be b = ±1/2 type. At 1000°C, no dislocation loops were observed and bubbles grew as a function of fluence attributed to vacancy mobility being higher and vacancy clusters becoming mobile

Collective modes and correlations in one-component plasmas

The static and time-dependent potential and surface charge correlations in a plasma with a boundary are computed for different shapes of the boundary. The case of a spheroidal or spherical one-component plasma is studied in detail because experimental results are available for such systems. Also, since there is some knowlegde both experimental and theoretical about the electrostatic collective modes of these plasmas, the time-dependent correlations are computed using a method involving these modes.Comment: 20 pages, plain TeX, submitted to Phys. Rev.