Imaging the transition between pre-planetary and planetary nebulae: : Integral Field Spectroscopy of hot post-AGB stars with NIFS

This is a pre-copyedited, author-produced PDF of an article accepted for publication in Monthly Notices of the Royal Astronomical Society following peer review. The version of record [T. M. Gledhill, and K. P. Forde, 'Imaging the transition between pre-planetary and planetary nebulae: integral field spectroscopy of hot post-AGB stars with NIFS', MNRAS, Vol. 447 (2): 1080-1095, February 2015] is available online at: https://doi.org/10.1093/mnras/stu2493.We present 2 to 2.4 micron integral field spectroscopy of a sample of hot post-AGB stars with early-B spectral types, using the NIFS instrument on Gemini North. These stars are just beginning to ionize their immediate environments and turn into planetary nebulae (PNe).We use molecular hydrogen emission lines together with hydrogen and helium recombination lines to explore the distribution of molecular and atomic gas and the extent of the developing ionized region. We see a range of evolutionary stages: IRAS 18062+2410 and IRAS 18379-1707 have recently developed compact and unresolved regions of photoionized H within axisymmetric molecular envelopes, with the former object increasing its Br-Gamma flux by a factor of 5.3 in 14 years; IRAS 22023+5249 and IRAS 20462+3416 have extended Br-Gamma nebulae and in the latter object only weak H2 emission remains; IRAS 19336-0400 is at a more advanced stage of PN formation where H2 is mostly dissociated and we see structure in both the H and He recombination line nebulae. IRAS 19200+3457 is the only object not to show the He I line at 2.058 micron and is probably the least evolved object in our sample; the H2 emission forms a ring around the star and we suggest that this object may be a rare example of a "round" pre-PN in transition to a "round" PN.Peer reviewedFinal Accepted Versio

Occurrence of 'Antrobathynella stammeri' (Jakobi, 1954) (Crustacea: Syncarida: Bathynellidae) in the hyporheic zones of two English karst rivers

This paper reports the first records of Antrobathynella stammeri in the British Isles since 1985. Numerous individuals were observed in hyporheic water extracted from the River Skirfare (Yorkshire, UK), whilst, in an independent study, a single confirmed specimen was recorded from hyporheic water pumped from the River Lathkill (Derbyshire, UK). The latter observation is the first record of the superorder Syncarida in the Peak District and provides an important geographical link between previously recorded individuals in Scotland and north-west England and records from the south of England. These records suggest that bathynellids may be more abundant in the UK than previously thought, highlighting the need for more effective sampling of subterranean habitats to determine the conservation status of such rarely seen species

Studies on the cimetidine resistant duodenal ulcer

This thesis investigates why some patients with duodenal ulcer do not respond to blockade and how these patients should be treated. Part 1 examines the effect of cimetidi.'ne lg/day, cimetidine 2g/day and vagotomy on nocturnal gastric secretion in nonresponders. Cimetidine in either dose had no significant effect on volume of gastric secretion but nocturnal intragastric acidity did show a significant decrease. Vagotomy significantly decreased both volume and acidity of secretion. These findings suggest that nonresponse to cimetidine may be due to increased vagal drive. Part 2 investigates vagal function further by measuring nocturnal pepsin secretion in patients receiving cimetidine and ranitidine. Both H2~receptor antagonists increased nocturnal pepsin secretion despite reducing acid. Previous reports suggest cimetidine inhibits pepsin out¬ put. However, patients whose acidity is controlled well with cimetidine have a rise in pH which, as pepsin is unstable at high pH values may result in pepsin deactivation . Patients whose acidity is only poorly controlled with cimetidine, therefore, do not denature pepsin, and as blockade increases vagal drive, intragastric pepsin rises. Duodenal ulcer activity correlates well with pepsin output. Thus, combination of poor acidity control with rise in intragastric pepsin results in nonresponse. Studies were also performed to investigate the mechanism of incre¬ ased pepsin secretion. These suggested that histamine may inhibit vagal drive and, therefore, blockade may increase vagal release. Cimetidine in combination with atropine 4.8mg/day resulted in a significant re¬ duction of volume, acid and pepsin secretion. This latter result suggests that cimetidine should be combined with an anticholinergic agent to inhibit vagal drive and improve control of gastric secretion which theoretically should provide improved clinical response to medical treatment

Mid-Infrared Imaging and Modelling of the Dust Shell around Post-AGB star HD 187885 (IRAS 19500-1709)

We present 10 and 20 micron images of IRAS 19500-1709 taken with the mid-infrared camera, OSCIR, mounted on the Gemini North Telescope. We use a 2-D dust radiation transport code to fit the spectral energy distribution from UV to sub-mm wavelengths and to simulate the images.Comment: 4 pages, 5 figures. To appear in "Asymmetric Planetary Nebulae III", eds. M.Meixner, J.Kastner, N.Soker & B.Balick. 2004, ASP Conference Serie

Using imprecise continuous time Markov chains for assessing the reliability of power networks with common cause failure and non-immediate repair.

We explore how imprecise continuous time Markov chains can improve traditional reliability models based on precise continuous time Markov chains. Specifically, we analyse the reliability of power networks under very weak statistical assumptions, explicitly accounting for non-stationary failure and repair rates and the limited accuracy by which common cause failure rates can be estimated. Bounds on typical quantities of interest are derived, namely the expected time spent in system failure state, as well as the expected number of transitions to that state. A worked numerical example demonstrates the theoretical techniques described. Interestingly, the number of iterations required for convergence is observed to be much lower than current theoretical bounds

Water mites: predators and parasites

The majority of water mites found in freshwater belong to the Hydrachnellae, a group which exhibit striking morphological diversity. This paper reviews work on the structure, morphology and taxonomy. The role of water mites as predators, their life history and their parasitic associations with aquatic insect or freshwater mollusc hosts is discussed along with the distribution of water mites in the British Isles

Integral field spectroscopy of H-2 and CO emission in IRAS 18276-1431 : evidence for ongoing post-AGB mass-loss

The definitive version can be found at: http://www.wiley.com/ Copyright Wiley BlackwellWe present K-band integral field spectroscopy of the bipolar post-asymptotic giant branch (post-AGB) object IRAS 18276-1431 (OH 17.7-2.0) using SINFONI on the VLT. This allows us to image both the continuum and molecular features in this object from 1.95 to 2.45 mu m with a spatial resolution down to 70 mas and a spectral resolution of similar to 5000. We detect a range of H-2 rovibrational emission lines which are consistent with shock excitation in regions of dense (similar to 10(7) cm(-3)) gas with shock velocities in the range of 25-30 km s(-1). The distribution of H-2 emission in the bipolar lobes suggests that a fast wind is impinging on material in the cavity walls and tips. H-2 emission is also seen along a line of sight close to the obscured star as well as in the equatorial region to either side of the stellar position which has the appearance of a ring with radius 0.3 arcsec. This latter feature may be radially cospatial with the boundary between the AGB and post-AGB winds. The first overtone (CO)-C-12 bandheads are observed longward of 2.29 mu m with the v = 2-0 bandhead prominently in emission. The CO emission has the same spatial distribution as the K-band continuum and therefore originates from an unresolved central source close to the star. We interpret this as evidence for ongoing mass-loss in this object. This conclusion is further supported by a rising K-band continuum indicating the presence of warm dust close to the star, possibly down to the condensation radius. The redshifted scattered peak of the CO bandhead is used to estimate a dust velocity along the bipolar axis of 95 km s(-1) for the collimated wind. This places a lower limit of similar to 125 yr on the age of the bipolar cavities, meaning that the collimated fast wind turned on very soon after the cessation of AGB mass-loss.Peer reviewe

A study into the variability of UK domestic energy assessments

In the UK, the residential sector accounts for around 29% of overall energy consumption. After transport, it is the largest single consumer of energy, and is responsible for approximately 14.5% of greenhouse gas emissions. There is a growing need to address this, if ambitious and binding targets are to be met by 2050. A fundamental part of this broad context is the ability to be able to measure the energy efficiency of a residential building accurately and consistently, so that progress against targets can be measured, current emissions can be calculated, and robust data can be used to formulate policy. The focus of this research is primarily that of assessing a property’s energy efficient status by the Domestic Energy Assessor (DEA), to ascertain whether there is variability in the results of the energy performance certificates (EPCs) they produce using the RdSAP software model, that will have implications for the wider context outlined here. In achieving this, the research utilises a mixed methods approach to look first at the findings of a number of semi-structured interviews with practising DEAs, and following this, it analyses site-based energy performance certificates (EPCs) undertaken by DEAs at two control properties. The information produced during both exercises is scrutinised, and synthesised with existing literature, and targets practitioners, academics and those involved in the creation of energy efficienct policy for residential buildings. The results present a contribution to knowledge by identifying variability within EPC outputs, which is widely acknowledged by practising DEAs, further supported during the site based study of two buildings, and underpinned by the literature. This variability may be attributed to different stages of the energy surveying process, and a variety of reasons, including the way the EPC is perceived (by both the DEAs producing them and the public), the training and experience of DEAs, how EPCs are audited, and conflicts of interest surrounding the commissioning of EPCs. The research concludes by summarising the findings and making proposals, which will help to support the development of a more effective process in assessing the energy efficient status of residential buildings