Evaluating EuroMET ‐ a Web‐based resource for meteorologists

Euro MET has been created to address the education and training needs of professional meteorologists and students in tertiary education throughout Europe and beyond Two module libraries have been developed for the WWW which are available in English, French, Spanish and German. The modules have been evaluated during their development and after completion. All the project partners used them in courses and training programmes within their institutions. This paper describes the formative and sum‐mative evaluation strategies used and some of the results obtained The efficacy of the evaluation approach adopted with respect to the size of the project is also discusse

A systematic look at the Very High and Low/Hard state of GX 339-4: Constraining the black hole spin with a new reflection model

We present a systematic study of GX 339-4 in both its very high and low hard states from simultaneous observations made with XMM-Newton and RXTE in 2002 and 2004. The X-ray spectra of both these extreme states exhibit strong reflection signatures, with a broad, skewed Fe-Kalpha line clearly visible above the continuum. Using a newly developed, self-consistent reflection model which implicitly includes the blackbody radiation of the disc as well as the effect of Comptonisation, blurred with a relativistic line function, we were able to infer the spin parameter of GX 339-4 to be 0.935 +/- 0.01 (statistical) +/- 0.01 (systematic) at 90 per cent confidence. We find that both states are consistent with an ionised thin accretion disc extending to the innermost stable circular orbit around the rapidly spinning black hole.Comment: 10 pages, 10 figures, accepted for publication in MNRAS 17/04/0

There’s no apprenticeship for Alzheimer’s: The caring relationship when an older person experiencing dementia falls

© Cambridge University Press 2011Older people experiencing dementia are twice as likely to fall with consequences of serious injury, reduction in everyday activity, admission to long-term care and mortality. Carers of people with dementia are themselves at greater risk of physical and mental ill health, which increases as the dementia progresses. Unsurprisingly, carer burden also increases when a care-recipient falls. The aim of this study was to explore the experiences of falling of community-living older people with dementia and their carers. A qualitative approach was taken using interpretative phenomenological analysis. Nine older people with predominantly Alzheimer's disease and their ten carers were recruited from a large mental health National Health Service trust and participated in one-to-one and joint in-depth interviews. Three dyads participated in repeat interviews. Three focus groups were also carried out, with nine older people experiencing memory problems and 12 carers from a local Alzheimer's Society branch. The antecedents, falls events and consequences of falls were discussed. This paper reports specifically on the impact of falls on the caring relationship. Three themes emerged: ‘learning as you go’, ‘we're always together’, ‘nobody was interested’. The findings demonstrate how falling accentuates the impact of dementia on the dyad. Spouse-carers' discussion of their own falls emphasise the need for joint assessment of health and wellbeing to reduce carer burden and preserve the couplehood of the dyad.The South West London NHS Mental Health Care Trust which part-funded this researc

Characteristics of temporal fluctuations in the hyperpolarized state of the cortical slow oscillation

We present evidence for the hypothesis that transitions between the low- and high-firing states of the cortical slow oscillation correspond to neuronal phase transitions. By analyzing intracellular recordings of the membrane potential during the cortical slow oscillation in rats, we quantify the temporal fluctuations in power and the frequency centroid of the power spectrum in the period of time before “down” to “up” transitions. By taking appropriate averages over such events, we present these statistics as a function of time before transition. The results demonstrate an increase in fluctuation power and time scale broadly consistent with the slowing of systems close to phase transitions. The analysis is complicated and limited by the difficulty in identifying when transitions begin, and removing dc trends in membrane potential

Complexity in de Sitter space

We consider the holographic complexity conjectures for de-Sitter invariant states in a quantum field theory on de Sitter space, dual to asymptotically anti-de Sitter geometries with de Sitter boundaries. The bulk holographic duals include solutions with or without a horizon. If we compute the complexity from the spatial volume, we find results consistent with general expectations, but the conjectured bound on the growth rate is not saturated. If we compute complexity from the action of the Wheeler–de Witt patch, we find qualitative differences from the volume calculation, with states of smaller energy having larger complexity than those of larger energy, even though the latter have bulk horizons

Iron fluorescence from within the innermost stable orbit of black hole accretion disks

The fluorescent iron Ka line is a powerful observational probe of the inner regions of black holes accretion disks. Previous studies have assumed that only material outside the radius of marginal stability can contribute to the observed line emission. Here, we show that fluorescence by material inside the radius of marginal stability, which is in the process of spiralling towards the event horizon, can have a observable influence on the iron line profile and equivalent width. For concreteness, we consider the case of a geometrically thin accretion disk, around a Schwarzschild black hole, in which fluorescence is excited by an X-ray source placed at some height above the disk and on the axis of the disk. Fully relativistic line profiles are presented for various source heights and efficiencies. It is found that the extra line flux generally emerges in the extreme red wing of the iron line, due to the large gravitational redshift experienced by photons from the region within the radius of marginal stability. We apply our models to the variable iron line seen in the ASCA spectrum of the Seyfert nucleus MCG-6-30-15. It is found that the change in the line profile, equivalent width, and continuum normalization, can be well explained as being due to a change in the height of the source above the disk. We discuss the implications of these results for distinguishing rapidly-rotating black holes from slowly rotating holes using iron line diagnostics.Comment: 20 pages, LaTeX. Accepted for publication in Astrophysical Journal. Figures 3 to 7 replaced with corrected versions (previous figures affected by calculational error). Some changes in the best fitting parameter

Fe K\alpha emission from photoionized slabs: the impact of the iron abundance

Iron K\alpha emission from photoionized and optically thick material is observed in a variety of astrophysical environments including X-ray binaries, active galactic nuclei, and possibly gamma-ray bursts. This paper presents calculations showing how the equivalent width (EW) of the Fe K line depends on the iron abundance of the illuminated gas and its ionization state -- two variables subject to significant cosmic scatter. Reflection spectra from a constant density slab which is illuminated with a power-law spectrum with photon-index \Gamma are computed using the code of Ross & Fabian. When the Fe K EW is measured from the reflection spectra alone, we find that it can reach values greater than 6 keV if the Fe abundance is about 10 times solar and the illuminated gas is neutral. EWs of about 1 keV are obtained when the gas is ionized. In contrast, when the EW is measured from the incident+reflected spectrum, the largest EWs are ~800 keV and are found when the gas is ionized. When \Gamma is increased, the Fe K line generally weakens, but significant emission can persist to larger ionization parameters. The iron abundance has its greatest impact on the EW when it is less than 5 times solar. When the abundance is further increased, the line strengthens only marginally. Therefore, we conclude that Fe K lines with EWs much greater than 800 eV are unlikely to be produced by gas with a supersolar Fe abundance. These results should be useful in interpreting Fe K emission whenever it arises from optically thick fluorescence.Comment: 5 pages, 5 figures, accepted by MNRAS Letter

The X-ray variability of the Seyfert~1 galaxy MCG-6-30-15 from long ASCA and RXTE observations

We present an analysis of the long RXTE observation of the Seyfert~1 galaxy MCG-6-30-15, taken in July 1997. Our results show that the behaviour is complicated. We find clear evidence from colour ratios and direct spectral fitting that changes to the intrinsic photon index are taking place. Spectral hardening is evident during periods of diminished intensity; in particular, a general trend for harder spectra is seen in the period following the hardest RXTE flare. Flux-correlated studies further show that the 3-10 keV photon index steepens while that in the 10-20 keV band, flattens with flux. The largest changes come from the spectral index below 10keV; however, changes in the intrinsic power law slope, and reflection both contribute in varying degrees to the overall spectral variability. We find that the iron line flux is consistent with being constant over large time intervals on the order of days (although the ASCA and RXTE spectra show that $F_{K\alpha}$ changes on shorter time intervals of order < 10ks), and equivalent width which anticorrelates with the continuum flux, and reflection fraction. Flux-correlated studies point at possible ionization signatures, while detailed spectral analysis of short time intervals surrounding flare events hint tentatively at observed spectral responses to the flare. We present a simple model for partial ionization where the bulk of the variability comes from within 6r_g. Temporal analysis further provides evidence for possible time (< 1000s) and phase (phi~0.6 rad) lags. Finally, we report an apparent break in the power density spectrum (~ 4-5 x 10^{-6}Hz) and a possible 33 hr period. Estimates for the mass of the black hole in MCG-6-30-15 are discussed in the context of spectral and temporal findings.Comment: 19 pages, 38 figures total (19 figure captions), accepted for publication in MNRAS July 200

The shallow depth emplacement of mafic intrusions on a magma-poor rifted margin : An example from the Bight Basin, Southern Australia

This work comprises a part of the Great Australian Bight Deepwater Marine Program (GABDMP) for funding this project. The GABDMP is a CSIRO research program, sponsored by Chevron Australia the results of which will be made publically available. 3D seismic data was gratefully provided by TGS. Dougal Jerram and Craig Magee are thanked for constructive reviews; Adam Bumby is thanked for editorial handling.Peer reviewedPostprin