11,766 research outputs found
Proton beam radiotherapy in the management of uveal melanoma: clinical experience in Scotland
<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 (1994â2005). 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>
The fierce urgency of now? Navigating paradoxes in sustainability education
This special section of the IJSHE brings together five papers originally presented at the fifth sustainability in higher education (SHE) conference, âThe fierce urgency of now? Navigating Paradoxes in Sustainability Education,â 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 âif our house is on fireâ. And then the Covid-19 pandemic struck [âŠ] 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
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 childrenâs 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 childrenâs 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
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
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?
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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