196 research outputs found

    Geophysical characterization of derelict coalmine workings and mineshaft detection: a case study from Shrewsbury, United Kingdom

    Get PDF
    A study site of derelict coalmine workings near Shrewsbury, United Kingdom was the focus for multi‐phase, near‐surface geophysical investigations. Investigation objectives were: 1) site characterization for remaining relict infrastructure foundations, 2) locate an abandoned coalmine shaft, 3) determine if the shaft was open, filled or partially filled and 4) determine if the shaft was capped (and if possible characterize the capping material). Phase one included a desktop study and 3D microgravity modelling of the relict coalmine shaft thought to be on site. In phase two, electrical and electromagnetic surveys to determine site resistivity and conductivity were acquired together with fluxgate gradiometry and an initial microgravity survey. Phase three targeted the phase two geophysical anomalies and acquired high‐resolution self potential and ground penetrating radar datasets. The phased‐survey approach minimised site activity and survey costs. Geophysical results were compared and interpreted to characterize the site, the microgravity models were used to validate interpretations. Relict buildings, railway track remains with associated gravel and a partially filled coalmine shaft were located. Microgravity proved optimal to locate the mineshaft with radar profiles showing ‘side‐swipe’ effects from the mineshaft that did not directly underlie survey lines. Geophysical interpretations were then verified with subsequent geotechnical intrusive investigations. Comparisons of historical map records with intrusive geotechnical site investigations show care must be taken using map data alone, as the latter mineshaft locations was found to be inaccurate

    Using automated imaging to interrogate gonadotrophin-releasing hormone receptor trafficking and function

    Get PDF
    Gonadotrophin-releasing hormone (GnRH) acts via seven transmembrane receptors on gonadotrophs to stimulate gonadotrophin synthesis and secretion, and thereby mediates central control of reproduction. Type I mammalian GnRHR are unique, in that they lack C-terminal tails. This is thought to underlie their resistance to rapid homologous desensitisation as well as their slow rate of internalisation and inability to provoke G-protein-independent (arrestin-mediated) signalling. More recently it has been discovered that the vast majority of human GnRHR are actually intracellular, in spite of the fact that they are activated at the cell surface by a membrane impermeant peptide hormone. This apparently reflects inefficient exit from the endoplasmic reticulum and again, the absence of the C-tail likely contributes to their intracellular localisation. This review is intended to cover some of these novel aspects of GnRHR biology, focusing on ways that we have used automated fluorescence microscopy (high content imaging) to explore GnRHR localisation and trafficking as well as spatial and temporal aspects of GnRH signalling via the Ca(2+)/calmodulin/calcineurin/NFAT and Raf/MEK/ERK pathways

    AFRP20: New P-Wavespeed Model for the African Mantle Reveals Two Whole-Mantle Plumes Below East Africa and Neoproterozoic Modification of the Tanzania Craton

    Get PDF
    Africa’s Cenozoic tectonism is often attributed to mantle plumes, particularly below East Africa, but their morphology, number, location, and impact on the African lithosphere are debated. The broad slow wavespeed African Superplume, ubiquitous in large-scale tomographic models, originates below South Africa, reaching the surface somewhere below East Africa. However, whether the diverse East African mantle geochemistry is best reconciled with one heterogeneous upwelling, or current tomographic models lack the resolution to image multiple distinct plumes, remains enigmatic. S-wavespeed tomographic images of Africa are legion, but higher-frequency P-wavespeed whole-mantle models possessing complementary diagnostic capabilities are comparatively lacking. This hinders attempts to disentangle the effects of Cenozoic hotspot tectonism and Pan African (and older) tectonic events on the East African lithosphere. Here we develop a continental-scale P-wave tomographic model capable of resolving structure from upper-to-lower mantle depths using a recently-developed technique to extract absolute arrival-times from noisy, temporary African seismograph deployments. Shallow-mantle wavespeeds are δVP ≈–4% below Ethiopia, but less anomalous (δVP ≥–2%) below other volcanic provinces. The heterogeneous African Superplume reaches the upper mantle below the Kenyan plateau. Below Ethiopia/Afar we image a second sub-vertical slow wavespeed anomaly rooted near the core-mantle boundary outside the African LLVP, meaning multiple disparately sourced whole-mantle plumes may influence East African magmatism. In contrast to other African cratons, wavespeeds below Tanzania are only fast to 90–135km depth. When interpreted alongside Lower Eocene on-craton kimberlites, our results support pervasive metasomatic lithospheric modification caused by subduction during the Neoproterozoic Pan-African orogeny.A. B. and S. C. are funded by the Natural Environment Research Council (NERC) Grant number NE/R010862/1 from PI Cottaar in Cambridge. A. B. was previously funded by the NERC Doctoral Training Partnership: Science and Solutions for a Changing Planet - Grant number NE/L002515/1 at Imperial College. I. B is funded by Natural Environment Research Council Grant number NE/S014136/1

    Acoustic wave propagation in the solar sub-photosphere with localised magnetic field concentration: effect of magnetic tension

    Get PDF
    Aims: We analyse numerically the propagation and dispersion of acoustic waves in the solar-like sub-photosphere with localised non-uniform magnetic field concentrations, mimicking sunspots with various representative magnetic field configurations. Methods: Numerical simulations of wave propagation through the solar sub-photosphere with a localised magnetic field concentration are carried out using SAC, which solves the MHD equations for gravitationally stratified plasma. The initial equilibrium density and pressure stratifications are derived from a standard solar model. Acoustic waves are generated by a source located at the height corresponding approximately to the visible surface of the Sun. By means of local helioseismology we analyse the response of vertical velocity at the level corresponding to the visible solar surface to changes induced by magnetic field in the interior. Results: The results of numerical simulations of acoustic wave propagation and dispersion in the solar sub-photosphere with localised magnetic field concentrations of various types are presented. Time-distance diagrams of the vertical velocity perturbation at the level corresponding to the visible solar surface show that the magnetic field perturbs and scatters acoustic waves and absorbs the acoustic power of the wave packet. For the weakly magnetised case, the effect of magnetic field is mainly thermodynamic, since the magnetic field changes the temperature stratification. However, we observe the signature of slow magnetoacoustic mode, propagating downwards, for the strong magnetic field cases

    Numerical simulations of the Accretion-Ejection Instability in magnetised accretion disks

    Get PDF
    The Accretion-Ejection Instability (AEI) described by Tagger & Pellat (1999) is explored numerically using a global 2d model of the inner region of a magnetised accretion disk. The disk is initially currentless but threaded by a vertical magnetic field created by external currents, and frozen in the flow. In agreement with the theory a spiral instability, similar in many ways to those observed in self-gravitating disks, develops when the magnetic field is, within a factor of a few, at equipartition with the disk thermal pressure. Perturbations in the flow build up currents and create a perturbed magnetic field within the disk. The present non-linear simulations give good evidence that such an instability can occur in the inner region of accretion disks, and generate accretion of gas and vertical magnetic flux toward the central object, if the equilibrium radial profiles of density and magnetic flux exceed a critical threshold.Comment: single tar file with GIF figure

    Orbital Advection by Interpolation: A Fast and Accurate Numerical Scheme for Super-Fast MHD Flows

    Full text link
    In numerical models of thin astrophysical disks that use an Eulerian scheme, gas orbits supersonically through a fixed grid. As a result the time step is sharply limited by the Courant condition. Also, because the mean flow speed with respect to the grid varies with position, the truncation error varies systematically with position. For hydrodynamic (unmagnetized) disks an algorithm called FARGO has been developed that advects the gas along its mean orbit using a separate interpolation substep. This relaxes the constraint imposed by the Courant condition, which now depends only on the peculiar velocity of the gas, and results in a truncation error that is more nearly independent of position. This paper describes a FARGO-like algorithm suitable for evolving magnetized disks. Our method is second order accurate on a smooth flow and preserves the divergence-free constraint to machine precision. The main restriction is that the magnetic field must be discretized on a staggered mesh. We give a detailed description of an implementation of the code and demonstrate that it produces the expected results on linear and nonlinear problems. We also point out how the scheme might be generalized to make the integration of other supersonic/super-fast flows more efficient. Although our scheme reduces the variation of truncation error with position, it does not eliminate it. We show that the residual position dependence leads to characteristic radial variations in the density over long integrations.Comment: 32 pages, 18 figures, accepted for publication in The Astrophysical Journal. Contains an additional appendix providing more details for some of the test problems (to be published as an addendum in the ApJS December 2008, v179n2 issue

    Real world evidence supports waking salivary cortisone as a screening test for adrenal insufficiency

    Get PDF
    Objective Worldwide, adults and children are at risk of adrenal insufficiency largely due to infectious diseases and adrenal suppression from use of anti-inflammatory glucocorticoids. Home waking salivary cortisone is an accurate screening test for adrenal insufficiency, it has potential to reduce costs, and patients prefer it to the adrenocorticotropin (ACTH) (synacthen) stimulation test. We carried out a service evaluation of home waking salivary cortisone in clinical care to identify implementation barriers. Design, Patients and Measurements Service evaluation in a centre where 212 patients referred for adrenal insufficiency had a waking salivary cortisone. Problems encountered during testing were recorded and patient feedback, via focus groups, collected. Results From all patients providing a waking salivary cortisone 55% had a normal test, 23% adrenal suppression, and 22% an equivocal result requiring a clinical centre ACTH stimulation test. The median (interquartile range [IQR]) for the time of the saliva sample was 07:40 (07:00–08:40). The median (IQR) days between collection and (i) delivery to local laboratory was 1 (0.25–2) day; (ii) reporting by local laboratory was 13 (11–18) days. Patients considered the test is “easy to do” and preferred it to the inpatient ACTH stimulation test. The principal challenge to clinical implementation was results reporting to clinicians due to delays at the local laboratory. Conclusions This service evaluation provides real-world evidence that home waking salivary cortisone is an effective, practical screening test for adrenal insufficiency. It identified key barriers to testing implementation that need to be addressed when introducing the test to a health service

    Evaluating a grant development public involvement funding scheme: a qualitative document analysis

    Get PDF
    Background Undertaking Patient and Public Involvement (PPI) when developing health and social care research grant applications is critical. However, researchers may not have any funding to undertake PPI when developing grants. In response, the National Institute for Health and Care Research- Research Design Service for Yorkshire and the Humber in the United Kingdom, provided Public Involvement Fund Awards of up to £600 to fund PPI activity when researchers were developing grant applications. Researchers provided post-activity reports about how they utilised the Public Involvement Fund. These reports were analysed with the aim of evaluating the usefulness of the Public Involvement Fund and to provide learning about supporting researchers to undertake PPI when developing grants. Methods The project was a qualitative document analysis of 55 reports. Initially a researcher coded four reports and three Public Contributors provided feedback. Researchers coded the remaining reports and identified key findings. A workshop was held with the three Public Contributors to develop the findings. Results Researchers accessing the Public Involvement Fund award were generally early career researchers or clinicians who did not have other sources of funding for pre-grant PPI input. Researchers felt the award was useful in enabling them to conduct PPI, which strengthened their grant applications. Some researchers found that the award limit of £600 and guidance encouraging expenditure within three months, made it difficult to undertake PPI throughout the full grant development process. Instead, the majority of researchers consulted Public Contributors on one or two occasions. Researchers struggled to recruit diverse members or run group sessions due to the time pressures of grant deadlines. Researchers wanted training on undertaking PPI alongside the financial support. Conclusions Researchers, especially early career researchers found having a Public Involvement Fund award instrumental in enabling them to undertake PPI when developing grant applications. It would be beneficial for similar schemes to be widely available. Schemes need to provide sufficient funding to enable meaningful PPI and allow researchers to hold the award for long enough to facilitate involvement during the whole grant development process. Researchers continue to need training on undertaking PPI
    corecore