11,766 research outputs found

    Proton beam radiotherapy in the management of uveal melanoma: clinical experience in Scotland

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    <p>Aim: To evaluate proton-beam radiotherapy (PBRT) in the management of uveal melanoma in Scotland.</p> <p>Methods: A retrospective review was undertaken on all patients receiving PBRT for uveal melanoma (1994–2005). Data obtained included: gender, past ocular/medical history, age, presenting complaint(s), diagnosis, laterality, tumor location/ultrasound characteristics, visual acuity (VA) and intraocular pressure. At post-treatment reviews (3, 6, 12, and 24 months), the following data was obtained: VA, intraocular pressure, tumor appearance and ultrasound characteristics. Mean follow up was 38.8 months.</p> <p>Results: Seventy-six patients were included. Mean age was 64 years; male to female ratio was 1.1:1. Ninety-seven percent demonstrated initial treatment response; 87% had successful control of tumor growth. Mean pre-treatment tumor height was 6.2 mm v.s. 4.8 mm post-irradiation (p < 0.001). Pre-irradiation VA was <3/60 in 18.5% compared with 74% post-irradiation (p < 0.0001). There was a statistically significant association between adverse events (enucleation, metastasis) and greater maximal basal tumor diameter. Eighteen eyes were enucleated. The median survival time was estimated to be 54 months.</p> <p>Conclusion: In our experience, PBRT is a precise, reliable and effective treatment in the management of large, and previously treated uveal melanomas. It prevents enucleation in the majority at short term follow-up.</p&gt

    The fierce urgency of now? Navigating paradoxes in sustainability education

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    This special section of the IJSHE brings together five papers originally presented at the fifth sustainability in higher education (SHE) conference, “The fierce urgency of now? Navigating Paradoxes in Sustainability Education,” hosted by Canterbury Christ Church, UK, in May 2020. Challenged by the words of Greta Thunberg spoken at the World Economic Forum in Davos in 2019, our aim was to provide a space to explore the role and responsibility of universities in a time of global crisis and to explore what it means to act as “if our house is on fire”. And then the Covid-19 pandemic struck [
] and the focus we had planned took on new relevance. Under lockdown conditions, the conference (and HE more generally) had to move to an online format, and we all found ourselves working in unchartered territory. Although challenging, this opened up unexpected opportunities for colleagues and students from different institutions nationally and internationally to participate, increasing diversity and repositioning the SHE networks as more outward-facing. This apparent contradiction (that is, locking down, opportunities may be opened up) illustrates one of the many apparent paradoxes in the contemporary higher educational landscape

    School Closures and Returning to School: Views of Parents of Children With Disabilities in England During the Covid-19 Pandemic

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    Children and young people with special educational needs and disabilities and their families are likely to be significantly affected by the Covid-19 pandemic at various levels, particularly given the implementation of school closures during national lockdowns. This study employed a survey design to assess parental perspectives on the impact of school closures and of returning to school in England, as a result of the Covid-19 pandemic. Eighty-three parents of children and young people with various types of need responded to the survey between September and December 2020. The survey included multiple choice questions and open-ended questions for further in-depth examination of parental perspectives. Results show that: the majority of parents reported that school closures had a detrimental effect on their children’s mental health (particularly those from the most deprived neighbourhoods) and on their own mental and physical health (particularly for ethnically diverse parents and for those whose children attend specialized settings); returning to school was considered to have a positive impact on children’s mental and physical health for the vast majority of parents, despite fearing exposure to the virus; many parents have reported that their children were calmer and happier at home during school closures and became more anxious and stressed upon returning to school. The role of cumulative risk in these children and families, as well as the role of schools as key support agents for the most vulnerable are discussed with implications for future research and policy

    Two Galaxy Clusters: A3565 and A3560

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    We report 102 new redshifts and magnitudes for a sample of galaxies to RF ~ 15.5 mag in a 2.17 deg x 2.17 deg region centered on the galaxy IC 4296, the most luminous member of the A3565 cluster. Up to the limiting magnitude we find 29 cluster members, and measure a velocity dispersion of 228 km/s. The estimated total mass for this system is ~ 3.0 x h**-1 10**13 Msun (where h = H0/100 km/s/Mpc), and its dynamical properties are quite typical of poor clusters presenting X-ray emission. We also find that galaxies with absorption lines are more concentrated towards the center of the cluster, while systems with emission lines are mainly located in the outer parts. The small velocity dispersion of the cluster, coupled to the known presence of an interacting pair of galaxies, and the large extent of the brightest cluster galaxy, could indicate that galaxy formation through mergers may still be underway in this system. The surveyed region also contains galaxies belonging to the Shapley Concentration cluster A3560. Within 30 arc min of the cluster center, we detect 32 galaxies, for which we measure a velocity dispersion of 588 km/s and a mass of ~2 x h**-1 10**14 Msun. However, because our sample is restricted to galaxies brighter than M*, these values should be considered only as rough estimates.Comment: 33 pages, including 6 tables and 9 postscript figures. Uses AAS Latex macros. Postscript file and ASCII versions of Tables 4 and 6 are available at http://www.dan.on.br/other_surveys/a3565.html. Scheduled for September 1999 issue of The Astronomical Journa

    X-ray total mass estimate for the nearby relaxed cluster A3571

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    We constrain the total mass distribution in the cluster A3571, combining spatially resolved ASCA temperature data with ROSAT imaging data with the assumption that the cluster is in hydrostatic equilibrium. The total mass within r_500 (1.7/h_50 Mpc) is M_500 = 7.8[+1.4,-2.2] 10^14/ h_50 Msun at 90% confidence, 1.1 times smaller than the isothermal estimate. The Navarro, Frenk & White ``universal profile'' is a good description of the dark matter density distribution in A3571. The gas density profile is shallower than the dark matter profile, scaling as r^{-2.1} at large radii, leading to a monotonically increasing gas mass fraction with radius. Within r_500 the gas mass fraction reaches a value of f_gas = 0.19[+0.06,-0.03] h_50^{-3/2} (90% confidence errors). Assuming that this value of f_gas is a lower limit for the the universal value of the baryon fraction, we estimate the 90% confidence upper limit of the cosmological matter density to be Omega_m < 0.4.Comment: 10 pages, 4 figures, accepted by Ap

    How much dark matter is there inside early-type galaxies?

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    We study the luminous mass as a function of the dynamical mass inside the effective radius (r_e) of early-type galaxies (ETGs) to search for differences between these masses. We assume Newtonian dynamics and that any difference between these masses is due to the presence of dark matter. We use several samples of ETGs -ranging from 19 000 to 98 000 objects- from the ninth data release of the Sloan Digital Sky Survey. We perform Monte Carlo (MC) simulations of galaxy samples and compare them with real samples. The main results are: i) MC simulations show that the distribution of the dynamical vs. luminous mass depends on the mass range where the ETGs are distributed (geometric effect). This dependence is caused by selection effects and intrinsic properties of the ETGs. ii) The amount of dark matter inside r_e is approximately 7% +- 22%. iii) This amount of dark matter is lower than the minimum estimate (10%) found in the literature and four times lower than the average (30%) of literature estimates. However, if we consider the associated error, our estimate is of the order of the literature average.Comment: 24 pages, 12 figures. MNRAS accepte
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