4,342 research outputs found

    Employer and labour provider perspectives on Eastern European migration to the UK

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    In a relatively short space of time Eastern Europe has become one of the principal source regions of migrants to the UK and citizens from these states now constitute some of the largest foreign-born populations in the country. This paper focuses on these trends from the perspective of UK employers and labour providers. Three main topics are covered; 1. The function served by East European migrant labour in the UK labour market and how this has changed over time. 2. Employers’ motivations for engaging with East European migrant labour. 3. The migration channels that shape how East European labour is sourced by UK employers. The findings demonstrate how the perspectives and practices of employers and recruiters can play an important role in influencing how East European labour migration flows to the UK are represented and produced

    Metastable phases and "metastable" phase diagrams

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    The work discusses specifics of phase transitions for metastable states of substances. The objects of condensed media physics are primarily equilibrium states of substances with metastable phases viewed as an exception, while the overwhelming majority of organic substances investigated in chemistry are metastable. It turns out that at normal pressure many of simple molecular compounds based on light elements (these include: most hydrocarbons; nitrogen oxides, hydrates, and carbides; carbon oxide (CO); alcohols, glycerin etc) are metastable substances too, i.e. they do not match the Gibbs' free energy minimum for a given chemical composition. At moderate temperatures and pressures, the phase transitions for given metastable phases throughout the entire experimentally accessible time range are reversible with the equilibrium thermodynamics laws obeyed. At sufficiently high pressures (1-10 GPa), most of molecular phases irreversibly transform to more energy efficient polymerized phases, both stable and metastable. These transformations are not consistent with the equality of the Gibbs' free energies between the phases before and after the transition, i.e. they are not phase transitions in "classical" meaning. The resulting polymeric phases at normal pressure can exist at temperatures above the melting one for the initial metastable molecular phase. Striking examples of such polymers are polyethylene and a polymerized modification of CO. Many of energy-intermediate polymeric phases can apparently be synthesized by the "classical" chemistry techniques at normal pressure.Comment: 5 pages, 4 figure

    Critical role of p38 MAPK for regeneration of the sciatic nerve following crush injury in vivo

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    BACKGROUND The physiological function of p38α, which is an isoform of p38 MAPK, has been investigated previously in several studies using pharmacological inhibitors. However, the results regarding whether p38α promotes or inhibits nerve regeneration in vivo have been controversial. METHODS We generated novel p38α mutant mice (sem mice) with a point mutation in the region encoding the p38α substrate-docking-site, which serves as a limited loss-of-function model of p38α. In the present study, we utilized sem mice and wild-type littermates (wt mice) to investigate the physiological role of p38α in nerve regeneration following crush injuries. RESULTS At four weeks after crush injury, the average axon diameter and the average axon area in sem mice were significantly smaller than those in wt mice. The average myelin sheath thickness in sem mice was reduced compared to wt mice, but no significant difference was observed in the G-ratio between the two groups. The sciatic functional index value demonstrated that functional nerve recovery in sem mice following crush injury was delayed, which is consistent with the histological findings. To investigate the underlying mechanisms of these findings, we examined inflammatory responses of the sciatic nerve by immunohistochemistry and western blotting. At an early phase following crush injury, sem mice showed remarkably lower expression of inflammatory cytokines, such as TNF-α and IL-1β, than wt mice. The expression of Caspase-3 and Tenascin-C were also lower in sem mice. Conversely, at a late phase of the response, sem mice showed considerably higher expression of TNF-α and of IL-1β with lower expression of S-100 than wt mice. CONCLUSIONS This is the first study of the physiological role of p38 MAPK in nerve regeneration that does not rely on the use of pharmacological inhibitors. Our results indicate that p38α insufficiency may cause an inflammatory disorder, resulting in a delay of histological and functional nerve recovery following crush injury. We conclude that p38 MAPK has an important physiological role in nerve regeneration and may be important for controlling both initiation of inflammation and recovery from nerve injury.Naoki Kato, Masahito Matsumoto, Masakazu Kogawa, Gerald J Atkins, David M Findlay, Takahiko Fujikawa, Hiromi Oda and Masato Ogat

    Coherent tune shift and instabilities measurements at the CERN Proton Synchrotron Booster

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    To understand one of the contributions to the intensity limitations of the CERN Proton Synchrotron Booster (PSB) in view of its operation with beams from Linac 4, the impedance of the machine has been characterized. Measurements of tune shift as a function of the intensity have been carried out in order to estimate the low frequency imaginary part of the impedance. Since the PSB is a low energy machine, these measurements have been done at two different energies, so as to enable us to disentangle the effect of the indirect space charge and resistive wall from the contribution of the machine impedance. An estimation of the possible resonant peaks in the impedance spectrum has been made by measuring a fast instability in Ring4

    High Intensity Beams from the CERN PS Booster

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    The CERN Proton Synchrotron Booster (PSB) has been running for more than 30 years. Originally designed to accelerate particles from 50 to 800 MeV, later upgradedto an energy of 1 GeV and finally 1.4 GeV, it is steadily being pushed to its operational limits. One challenge is the permanent demand for intensity increase, in particular for CNGS and ISOLDE, but also in view of Linac4. As it is an accelerator working with very high space charge during the low energy part of its cycle, its operational conditions have to be precisely tuned. Amongst other things resonances must be avoided, stop band crossings optimised and the machine impedance minimised. Recently, an operational intensity record was achieved with >4.25×1013 protons accelerated. An orbit correction campaign performed during the 2007/2008 shutdown was a major contributing factor to achieving this intensity. As the PSB presently has very few orbit correctors available,the orbit correction has to be achieved by displacing and/or tilting some of the defocusing quadrupoles common to all 4 PSB rings. The contributing factors used to optimise performance will be reviewed

    The core planar cell polarity gene, Vangl2, directs adult corneal epithelial cell alignment and migration

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    This work was supported by a Biotechnology and Biological Sciences Research Council (BBSRC) DTG PhD studentship to A.F., an Anatomical Society PhD Studentship (‘The Roles of planar cell polarity genes in a classical anatomical system: the cornea’) to D.A.P./J.M.C. and BBSRC Project Grants BB/J015172/1 and BB/J015237/1 to J.D.W. and J.M.C., respectively.Peer reviewedPublisher PD

    Three-Dimensional FDTD Simulation of Biomaterial Exposure to Electromagnetic Nanopulses

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    Ultra-wideband (UWB) electromagnetic pulses of nanosecond duration, or nanopulses, have been recently approved by the Federal Communications Commission for a number of various applications. They are also being explored for applications in biotechnology and medicine. The simulation of the propagation of a nanopulse through biological matter, previously performed using a two-dimensional finite difference-time domain method (FDTD), has been extended here into a full three-dimensional computation. To account for the UWB frequency range, a geometrical resolution of the exposed sample was 0.25mm0.25 mm, and the dielectric properties of biological matter were accurately described in terms of the Debye model. The results obtained from three-dimensional computation support the previously obtained results: the electromagnetic field inside a biological tissue depends on the incident pulse rise time and width, with increased importance of the rise time as the conductivity increases; no thermal effects are possible for the low pulse repetition rates, supported by recent experiments. New results show that the dielectric sample exposed to nanopulses behaves as a dielectric resonator. For a sample in a cuvette, we obtained the dominant resonant frequency and the QQ-factor of the resonator.Comment: 15 pages, 8 figure

    Search for Point Sources of Ultra-High Energy Cosmic Rays Above 40 EeV Using a Maximum Likelihood Ratio Test

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    We present the results of a search for cosmic ray point sources at energies above 40 EeV in the combined data sets recorded by the AGASA and HiRes stereo experiments. The analysis is based on a maximum likelihood ratio test using the probability density function for each event rather than requiring an a priori choice of a fixed angular bin size. No statistically significant clustering of events consistent with a point source is found.Comment: 7 pages, 7 figures. Accepted for publication in The Astrophysical Journa
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