Line width distributions as evidence for axisymmetry in the broad line regions of active galaxies

The nuclei of a wide class of active galaxies emit broad emission lines with widths at half maximum (FWHM) in the range $10^{3}-10^{4}$ km s$^{-1}$. This spread of widths is not solely a consequence of the range of the luminosities of these sources since a plot of width versus luminosity shows a large scatter. We propose that the broad line emission region (BLR) is axially symmetric and that this scatter in line width arises from an additional dependence on the angle of the line of sight to the axis of the emission region. Such a relation is natural in unified models of active nuclei which link a variety of observed properties to viewing angle. Adopting a simple form for the line width as a function of luminosity and angle, and convolving this with the observed luminosity function, allows us to predict a line width distribution consistent with the available data. Furthermore, we use the relation between the equivalent width of a line and the luminosity in the continuum (the `Baldwin Effect') to predict an observed correlation between line width and equivalent width. The scatter on this correlation is again provided by angular dependence. The results have applications as diagnostics of models of the broad line emission region and in cosmology.Comment: 8 pages including 4 figures. Accepted for publication in MNRAS Letter

The luminosity dependence of opening angle in unified models of active galaxies

In unified models of active galaxies the direct line of sight to the nucleus is unobscured only within a certain cone of directions. An opening angle for this cone is usually estimated by methods such as the overall ratio of Seyfert 1s to Seyfert2s, the latter assumed to be obscured versions of the former. Here we shall show, as has often been suspected, that the opening angle of the cone depends on the luminosity of the central source, with higher luminosities corresponding to larger opening angles. This conclusion depends only on the assumption that the width of the broad emission lines at a given luminosity is a measure of inclination angle, an assumption that is supported by observation in radio-loud systems. On the other hand we show that the scatter in X-ray spectral index is not primarily an effect of viewing angle, in contrast to what might be expected if the scatter on the spectral index versus luminosity relation were a consequence of absorption in the obscuring material. The observed correlation between linewidth and spectral index appears to be a further consequence of the dependence of opening angle on luminosity.Comment: 8 pages, 7 figures, uses mn.sty. Accepted for publication in MNRA

Determining the cosmological parameters from the linewidths of active galaxies

We have previously shown that the linewidth distribution in AGN can be accounted for by an axisymmetric broad emission line region. In this paper we show that the linewidth distribution changes with redshift and that these changes are dependent on H_0 and q_0. We show that relatively small samples of AGN at high redshift with measured linewidth at half maximum can be used to distinguish between values of H_0 and q_0. Furthermore larger low redshift samples can be used to distinguish between luminosity functions and hence different models of quasar evolution.Comment: Accepted for publication in MNRAS. 8 pages LaTeX, uses mn.st

Do the UK government's new Quality and Outcomes Framework (QOF) scores adequately measure primary care performance? A cross-sectional survey of routine healthcare data

BACKGROUND General practitioners' remuneration is now linked directly to the scores attained in the Quality and Outcomes Framework (QOF). The success of this approach depends in part on designing a robust and clinically meaningful set of indicators. The aim of this study was to assess the extent to which measures of health observed in practice populations are correlated with their QOF scores, after accounting for the established associations between health outcomes and socio-demographics. METHODS QOF data for the period April 2004 to March 2005 were obtained for all general practices in two English Primary Care Trusts. These data were linked to data for emergency hospital admissions (for asthma, cancer, chronic obstructive pulmonary disease, coronary hear disease, diabetes, stroke and all other conditions) and all cause mortality for the period September 2004 to August 2005. Multilevel logistic regression models explored the association between health outcomes (hospital admission and death) and practice QOF scores (clinical, additional services and organisational domains), age, sex and socio-economic deprivation. RESULTS Higher clinical domain scores were generally associated with lower admission rates and this was significant for cancer and other conditions in PCT 2. Higher scores in the additional services domain were associated with higher admission rates, significantly so for asthma, CHD, stroke and other conditions in PCT 1 and cancer in PCT 2. Little association was observed between the organisational domain scores and admissions. The relationship between the QOF variables and mortality was less clear. Being female was associated with fewer admissions for cancer and CHD and lower mortality rates. Increasing age was mainly associated with an increased number of events. Increasing deprivation was associated with higher admission rates for all conditions and with higher mortality rates. CONCLUSION The associations between QOF scores and emergency admissions and mortality were small and inconsistent, whilst the impact of socio-economic deprivation on the outcomes was much stronger. These results have implications for the use of target-based remuneration of general practitioners and emphasise the need to tackle inequalities and improve the health of disadvantaged groups and the population as a whole

Dynamics of Vortex Core Switching in Ferromagnetic Nanodisks

Dynamics of magnetic vortex core switching in nanometer-scale permalloy disk, having a single vortex ground state, was investigated by micromagnetic modeling. When an in-plane magnetic field pulse with an appropriate strength and duration is applied to the vortex structure, additional two vortices, i.e., a circular- and an anti-vortex, are created near the original vortex core. Sequentially, the vortex-antivortex pair annihilates. A spin wave is created at the annihilation point and propagated through the entire element; the relaxed state for the system is the single vortex state with a switched vortex core.Comment: to appear in Appl. Phys. Let

Genome-wide association study of behavioural and psychiatric features in human prion disease.

Prion diseases are rare neurodegenerative conditions causing highly variable clinical syndromes, which often include prominent neuropsychiatric symptoms. We have recently carried out a clinical study of behavioural and psychiatric symptoms in a large prospective cohort of patients with prion disease in the United Kingdom, allowing us to operationalise specific behavioural/psychiatric phenotypes as traits in human prion disease. Here, we report exploratory genome-wide association analysis on 170 of these patients and 5200 UK controls, looking for single-nucleotide polymorphisms (SNPs) associated with three behavioural/psychiatric phenotypes in the context of prion disease. We also specifically examined a selection of candidate SNPs that have shown genome-wide association with psychiatric conditions in previously published studies, and the codon 129 polymorphism of the prion protein gene, which is known to modify various aspects of the phenotype of prion disease. No SNPs reached genome-wide significance, and there was no evidence of altered burden of known psychiatric risk alleles in relevant prion cases. SNPs showing suggestive evidence of association (P<10(-5)) included several lying near genes previously implicated in association studies of other psychiatric and neurodegenerative diseases. These include ANK3, SORL1 and a region of chromosome 6p containing several genes implicated in schizophrenia and bipolar disorder. We would encourage others to acquire phenotype data in independent cohorts of patients with prion disease as well as other neurodegenerative and neuropsychiatric conditions, to allow meta-analysis that may shed clearer light on the biological basis of these complex disease manifestations, and the diseases themselves

Constraining mantle carbon: CO2-trace element systematics in basalts and the roles of magma mixing and degassing

Our present understanding of the mantle carbon budget is in part built upon measurements of carbon concentrations in olivine hosted melt inclusions. Only a small number of such datasets are thought to have avoided degassing, having been entrapped prior to CO2 vapour saturation, and are therefore able to constrain primary CO2 concentrations. The absence of degassing in melt inclusion datasets has been inferred from the presence of strong correlations between CO2 and trace elements. In this contribution, we demonstrate that partial degassing followed by magma mixing not only retains such positive correlations, but can enhance them. Simple models of magma mixing and degassing are used to characterise how CO2-trace element systematics respond to CO2 vapour saturation in primary mantle melts entering the crust, followed by magma mixing. Positive correlations are expected between CO2 and most trace elements, and the average CO2/Ba and CO2/Nb ratios are controlled by the pressure of magma storage, rather than the CO2 concentration in the mantle. We find that the best estimates of mantle CO2 are the maximum CO2/Ba ratios observed in melt inclusion datasets, though a large number of analyses are required to adequately characterise the maximum of the CO2/Ba distribution. Using the mixing and degassing models we estimate the number of analyses required to obtain a maximum CO2/Ba observation within 10% of the mantle value. In light of our results, we reassess existing melt inclusion datasets, and find they exhibit systematics associated with partial degassing and mixing. We argue that all the data presently available is consistent with a depleted mantle CO2/Ba ratio of ~140, and there is as yet no evidence for heterogeneity in the CO2/Ba ratio of the depleted mantle

The global melt inclusion C/Ba array: Mantle variability, melting process, or degassing?

The Earth’s mantle holds more carbon than its oceans, atmosphere and con- tinents combined, yet the distribution of carbon within the mantle remains uncertain. Our best constraints on the distribution of carbon within the up- per mantle are derived from the carbon-trace element systematics of ultra- depleted glasses and melt inclusions from mid-ocean ridge basalts. How- ever, carbon-trace element systematics are susceptible to modification by crustal processes, including concurrent degassing and mixing, and melt in- clusion decrepitation. In this study we explore how the influence of these processes varies systematically with both the mantle source and melting pro- cess, thereby modulating both global and local carbon-trace element trends. We supplement the existing melt inclusion data from Iceland with four new datasets, significantly enhancing the spatial and geochemical coverage of melt inclusion datasets from the island. Within the combined Iceland dataset there is significant variation in melt inclusion C/Ba ratio, which is tightly correlated with trace element enrichment. The trends in C/Ba- Ba space displayed by our new data coincide with the same trends in data compiled from global ocean islands and mid-ocean ridges, forming a global array. The overall structure of the global C/Ba-Ba array is not a property of the source, instead it is controlled by CO2 vapour loss pre- and post-melt inclusion entrapment; i.e., the array is a consequence of degassing creating near-constant maximum melt-inclusion carbon contents over many orders of magnitude of Ba concentration. On Iceland, extremely high C/Ba (>100) and C/Nb (>1000) ratios are found in melt inclusions from the most depleted eruptions. The high C/Ba and C/Nb ratios are unlikely to be either analytical artefacts, or to be the product of extreme fractionation of the most incompatible elements during silicate melting. Whilst high C/Ba and C/Nb ratios could be generated by regassing of melt inclusions by CO2 vapour, or by mantle melting occurring in the presence of residual graphite, we suggest the high values most likely derive from an intrinsically high C/Ba and C/Nb mantle component that makes up a small fraction of the Icelandic mantle

An equilibrium model for ribosome competition

The number of ribosomes in a cell is considered as limiting, and gene expression is thus largely determined by their cellular concentration. In this work we develop a toy model to study the trade-off between the ribosomal supply and the demand of the translation machinery, dictated by the composition of the transcript pool. Our equilibrium framework is useful to highlight qualitative behaviours and new means of gene expression regulation determined by the fine balance of this trade-off. We also speculate on the possible impact of these mechanisms on cellular physiology

Мовні реалії іншого часу і простору (про особливості слововживання у творах Івана Багряного)

The structure of Earthʼs deep inner core has important implications for core evolution, since it is thought to be related to the early stages of core formation. Previous studies have suggested that there exists an innermost inner core with distinct anisotropy relative to the rest of the inner core. Using an extensive new data set of handpicked absolute travel time observations of the inner core phase PKIKP, we find that the data are best explained by variations in anisotropy between two hemispheres and do not require an innermost inner core. We demonstrate that observations of an innermost inner core are an artifact from averaging over lateral anisotropy variations. More significantly we show that hemispherical variations in anisotropy, previously only imaged in the upper inner core, continue to its centre. The eastern region has 0.5–1.5% anisotropy, whereas the western region has 3.5–8.8% anisotropy increasing with depth, with a slow direction at 57–61° to the Earthʼs rotation axis at all depths. Such anisotropy is consistent with models of aligned hcp or bcc iron aggregates