21,819 research outputs found

    Multiplicity of fibronectin-binding alpha V integrin receptors in colorectal cancer.

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    Current data from in vitro and in vivo animal models indicate that fibronectin-binding integrin receptors expressed by colon cancer cells may regulate tumour growth. While individual members of the beta 1 subfamily of integrins have now been clearly identified in colorectal cancer, little information exists with respect to the alpha V subfamily. In the present study we show that alpha V can associate with multiple and different beta subunits capable of binding fibronectin in this tumour type. This is likely to have functional implications for growth and spread of colorectal cancer

    Online learning : towards enabling choice

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    Education is rapidly evolving from an opportunity that was provided mainly for an elite to one that is available to a mass markets and as such is prone to the forces generated by this environment. Where, in the established pattern, commercial interest was limited mainly to the use of skills developed during the educational process, the future model of educational provision will involve extensive commercial activity in the production, delivery and marketing of material. Already there are a number of commercial companies offering framework products enabling "off the shelf solutions" for the construction and delivery of web based courses in any subject area. The commercialisation of education is underway and it is inevitable that it will be viewed, by entrepreneurs and customers alike, as any other commercial product. It would seem reasonable that the consumer should be able to evaluate the performance of these new modes of working in a similar manner to other commercial products. This paper draws together current thinking on the problems associated with evaluating computer and communication based learning

    When Peace is Not Enough: The Flag Protests and The Politics of Identity and Belonging in East Belfast

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    The flag protests that occurred during the tail of 2012 and early 2013 gained international media attention. Much of the media attention focused on the involvement of young people and sought to seek answers to how young people who had grown up in more peaceful times could be involved in violence that belonged in Northern Ireland’s past. Research being conducted by the authors during the course of the flag protests on young people’s experiences of living in post conflict Belfast enabled the researchers to gain insight and clarity on the flag protests, why they had occurred and underlying factors that fuelled the riots and violence that followed, giving a snap shot of the strength of feeling and overall mood of the Protestant community at that time. Using an interpretative phenomenological analysis (IPA) approach, 2 focus groups with 14 young people aged between 15-24 (M=17 years), were conducted followed by more in-depth semi structured interviews with 6 young people from the focus groups and a further 6 interviews with youth and community workers from the East Belfast area

    Measurements of Surface Diffusivity and Coarsening During Pulsed Laser Deposition

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    Pulsed Laser Deposition (PLD) of homoepitaxial SrTiO3 was studied with in-situ x-ray specular reflectivity and surface diffuse x-ray scattering. Unlike prior reflectivity-based studies, these measurements access both the time- and the length-scales of the evolution of the surface morphology during growth. In particular, we show that this technique allows direct measurements of the diffusivity for both inter- and intra-layer transport. Our results explicitly limit the possible role of island break-up, demonstrate the key roles played by nucleation and coarsening in PLD, and place an upper bound on the Ehrlich-Schwoebel (ES) barrier for downhill diffusion

    Direct evidence for an early reionization of the Universe?

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    We examine the possible reionization of the intergalactic medium (IGM) by the source UDF033238.7-274839.8 (hereafter HUDF-JD2), which was discovered in deep {\it HST}/VLT/{\it Spitzer} images obtained as part of the Great Observatory Origins Deep Survey and {\it Hubble} Ultra-Deep Field projects. Mobasher et al (2005) have identified HUDF-JD2 as a massive (6×1011M\sim6\times10^{11}M_\odot) post-starburst galaxy at redshift z6.5\gtrsim6.5. We find that HUDF-JD2 may be capable of reionizing its surrounding region of the Universe, starting the process at a redshift as high as z15±5\approx 15 \pm5.Comment: 6 pages, 2 figures. Accepted for publication in ApJ Letter

    Deep UV Luminosity Functions at the Infall Region of the Coma Cluster

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    We have used deep GALEX observations at the infall region of the Coma cluster to measure the faintest UV luminosity functions (LFs) presented for a rich galaxy cluster thus far. The Coma UV LFs are measured to M_UV = -10.5 in the GALEX FUV and NUV bands, or 3.5 mag fainter than previous studies, and reach the dwarf early-type galaxy population in Coma for the first time. The Schechter faint-end slopes (alpha = -1.39 in both GALEX bands) are shallower than reported in previous Coma UV LF studies owing to a flatter LF at faint magnitudes. A Gaussian-plus-Schechter model provides a slightly better parametrization of the UV LFs resulting in a faint-end slope of ~ -1.15 in both GALEX bands. The two-component model gives faint-end slopes shallower than -1 (a turnover) for the LFs constructed separately for passive and star forming galaxies. The UV LFs for star forming galaxies show a turnover at M_UV ~ -14 owing to a deficit of dwarf star forming galaxies in Coma with stellar masses below M*=10^8 Msun. A similar turnover is identified in recent UV LFs measured for the Virgo cluster suggesting this may be a common feature of local galaxy clusters, whereas the field UV LFs continue to rise at faint magnitudes. We did not identify an excess of passive galaxies as would be expected if the missing dwarf star forming galaxies were quenched inside the cluster. In fact, the LFs for both dwarf passive and star forming galaxies show the same turnover at faint magnitudes. We discuss the possible origin of the missing dwarf star forming galaxies in Coma and their expected properties based on comparisons to local field galaxies.Comment: accepted for publication in Ap

    ACS photometry of extended, luminous globular clusters in the outskirts of M31

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    A new population of extended, luminous globular clusters has recently been discovered in the outskirts of M31. These objects have luminosities typical of classical globular clusters, but much larger half-light radii. We report the first results from deep ACS imaging of four such clusters, one of which is a newly-discovered example lying at a projected distance of ~60 kpc from M31. Our F606W, F814W colour-magnitude diagrams extend ~3 magnitudes below the horizontal branch level, and clearly demonstrate, for the first time, that all four clusters are composed of >10 Gyr old, metal-poor stellar populations. No evidence for multiple populations is observed. From a comparison with Galactic globular cluster fiducials we estimate metallicities in the range -2.2 < [Fe/H] < -1.8. The observed horizontal branch morphologies show a clear second parameter effect between the clusters. Preliminary radial luminosity profiles suggest integrated magnitudes in the range -6.6 < M_V < -7.7, near the median value of the globular cluster luminosity function. Our results confirm that these four objects are bona fide old, metal-poor globular clusters, albeit with combined structures and luminosities unlike those observed for any other globular clusters in the Local Group or beyond.Comment: 12 pages, 3 figures, 1 table; accepted for publication in ApJ Letter
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