29 research outputs found
Did the London Initiative Zone investment programme affect general practice structure and performance in East London? A time series analysis of cervical screening coverage and asthma prescribing
A programme of incentives was set up in the London Initiative Zones to improve primary care in inner London based on the findings of the Tomlinson Enquiry in 1992. This descriptive study is a 4-y time series analysis of changes in general practice structure in East London as the result of London Initiative Zone investment, and an exploration of the possible effect of investment on practice performance.We used routinely available administrative data for the whole analysis. General practice characteristics and two selected performance indicators: the asthma prophylaxis to bronchodilator ratio and cervical cytology screening rate, for all practices in the East London and the City Health Authority for 4 y, 1993-1996, were used. Both reflect practice efficiency, but relate to different aspects of practice performance. The prescribing indicator is more indicative of the quality of clinical practise, whereas cervical screening coverage relates more to the characteristics of the practice population and to practice organisation. Repeated measures analyses were used to identify trends and to explore the relationship between changes in practice characteristics and performance. Graphical methods were used to compare East London trends with the rest of England.There were significant improvements in practice structure as the consequence of London Initiative Zone investment. There was a positive association with improvements in practice performance, but East London still lagged some way behind national patterns. The findings suggest that while improvements in asthma prescribing follow the national trend, practices have difficulty in achieving and sustaining the 80% target for cervical cytology screening, and that an overall population coverage of 80% may be in doubt.Increased investment in practice staffing may be influential in improving some aspects of performance. However, in common with other inner cities, a greater effort and more innovative strategies may be needed to achieve a standard of performance equal to the best
Galaxy And Mass Assembly (GAMA): testing galaxy formation models through the most massive galaxies in the Universe
We have analysed the growth of Brightest Group Galaxies and Brightest Cluster Galaxies (BGGs/BCGs) over the last 3 billion years using a large sample of 883 galaxies from the Galaxy And Mass Assembly survey. By comparing the stellar mass of BGGs and BCGs in groups and clusters of similar dynamical masses, we find no significant growth between redshift z = 0.27 and 0.09. We also examine the number of BGGs/BCGs that have line emission, finding that approximately 65 per cent of BGGs/BCGs show Hα in emission. From the galaxies where the necessary spectroscopic lines were accurately recovered (54 per cent of the sample), we find that half of this (i.e. 27 per cent of the sample) harbour ongoing star formation with rates up to 10 M⊙ yr−1, and the other half (i.e. 27 per cent of the sample) have an active nucleus (AGN) at the centre. BGGs are more likely to have ongoing star formation, while BCGs show a higher fraction of AGN activity. By examining the position of the BGGs/BCGs with respect to their host dark matter halo, we find that around 13 per cent of them do not lie at the centre of the dark matter halo. This could be an indicator of recent cluster–cluster mergers. We conclude that BGGs and BCGs acquired their stellar mass rapidly at higher redshifts as predicted by semi-analytic models, mildly slowing down at low redshifts
Galaxy And Mass Assembly (GAMA): data release 4 and the z < 0.1 total and z < 0.08 morphological galaxy stellar mass functions
Galaxie
The modelling and control of failure in bi-material ceramic laminates
Recent experimental and theoretical work on simple, single phase, laminated systems has indicated that failure resistant ceramics can be produced using an elegant method that avoids many of the problems and limitations of comparable fibrous ceramic composites. Theoretical work on these laminated systems has shown good agreement with experiment and simulated the effects of material properties and laminate structure on the composite performance. This work has provided guidelines for optimised laminate performance. In the current study, theoretical work has been simply extended to predict the behaviour of bi-material laminates with alternating layers of weak and strong material with different stiffnesses. Expressions for the strain energy release rates of internal advancing cracks are derived and combined with existing criteria to predict the failure behaviour of these laminates during bending. The modelling indicates three modes of failure dictated by the relative proportions, thicknesses and interfacial properties of the weak and strong phases. A critical percentage of strong phase is necessary to improve failure behaviour, in an identical argument to that for fibre composites. Incorporation of compliant layers is also investigated and implications for laminate design discussed
Galaxy and Mass Assembly (GAMA): the GAMA galaxy group catalogue (GCv1)
Using the complete GAMA-I survey covering ~142 sq. deg. to r=19.4, of which
~47 sq. deg. is to r=19.8, we create the GAMA-I galaxy group catalogue (G3Cv1),
generated using a friends-of-friends (FoF) based grouping algorithm. Our
algorithm has been tested extensively on one family of mock GAMA lightcones,
constructed from Lambda-CDM N-body simulations populated with semi-analytic
galaxies. Recovered group properties are robust to the effects of interlopers
and are median unbiased in the most important respects. G3Cv1 contains 14,388
galaxy groups (with multiplicity >= 2$), including 44,186 galaxies out of a
possible 110,192 galaxies, implying ~40% of all galaxies are assigned to a
group. The similarities of the mock group catalogues and G3Cv1 are multiple:
global characteristics are in general well recovered. However, we do find a
noticeable deficit in the number of high multiplicity groups in GAMA compared
to the mocks. Additionally, despite exceptionally good local spatial
completeness, G3Cv1 contains significantly fewer compact groups with 5 or more
members, this effect becoming most evident for high multiplicity systems. These
two differences are most likely due to limitations in the physics included of
the current GAMA lightcone mock. Further studies using a variety of galaxy
formation models are required to confirm their exact origin.Comment: 31 pages, 22 figures (lo-res astro-ph, hi-res on demand or via
MNRAS), accepted for publication in MNRA