Traumatic Brain Injury: Informed Accommodation in the Classroom

This paper discusses traumatic brain injury (TBI) and the symptoms that affect a student emotionally, cognitively and socially after experiencing a TBI. Traumatic brain injuries can have a profoundly negative impact on a child’s ability to learn at school and interact with peers in social situations. Recent research shows how TBI affects brain function and the impacts that this can have on education. However, research also suggests effective strategies that teachers can use in their classroom when teaching a student who has experienced a TBI

Laser-produced plasma EUV light source with isolated plasma

An EUV radiation source that includes a nozzle positioned a far enough distance away from a target region so that EUV radiation generated at the target region by a laser beam impinging a target stream emitted from the nozzle is not significantly absorbed by target vapor proximate the nozzle. Also, the EUV radiation does not significantly erode the nozzle and contaminate source optics. In one embodiment, the nozzle is more than 10 cm away from the target region

Surface superconducting states in a polycrystalline MgB2_{2} sample

We report results of dc magnetic and ac linear low-frequency study of a polycrystalline MgB$_2$ sample. AC susceptibility measurements at low frequencies, performed under dc fields parallel to the sample surface, provide a clear evidence for surface superconducting states in MgB$_2$.Comment: 4 pages and 5 figure

PYG4OMETRY: a Python library for the creation of Monte Carlo radiation transport physical geometries

Creating and maintaining computer readable geometries for use in Monte Carlo Radiation Transport (MCRT) simulations is an error-prone and time-consuming task. Simulating a system often requires geometry from different sources and modelling environments, including a range of MCRT codes and computer-aided design (CAD) tools. PYG4OMETRY is a Python library that enables users to rapidly create, manipulate, display, read and write Geometry Description Markup Language (GDML)-based geometry used in simulations. PYG4OMETRY provides importation of CAD files to GDML tessellated solids, conversion of GDML geometry to FLUKA and conversely from FLUKA to GDML. The implementation of PYG4OMETRY is explained in detail along with small examples. The paper concludes with a complete example using most of the PYG4OMETRY features and a discussion of extensions and future work

BDSIM: An Accelerator Tracking Code with Particle-Matter Interactions

Beam Delivery Simulation (BDSIM) is a program that simulates the passage of particles in a particle accelerator. It uses a suite of standard high energy physics codes (Geant4, ROOT and CLHEP) to create a computational model of a particle accelerator that combines accurate accelerator tracking routines with all of the physics processes of particles in Geant4. This unique combination permits radiation and detector background simulations in accelerators where both accurate tracking of all particles is required over long range or over many revolutions of a circular machine, as well as interaction with the material of the accelerator.Comment: 20 pages, 17 figures. Accepted for publication 28th Jan 202

Photon Trapping Enables Super-Eddington Growth of Black-Hole Seeds in Galaxies at High Redshift

We identify a physical mechanism that would have resulted in rapid, obscured growth of seed super-massive black-holes in galaxies at z>6. Specifically, we find that the density at the centre of typical high redshift galaxies was at a level where the Bondi accretion rate implies a diffusion speed of photons that was slower than the gravitational infall velocity, resulting in photons being trapped within the accretion flow and advected into the black-hole. We show that there is a range of black-hole masses (M_bh ~ 10^3-10^5 solar masses) where the accretion flow traps radiation, corresponding to black-holes that were massive enough to generate a photon trapping accretion flow, but small enough that their Bondi radii did not exceed the isothermal scale height of self-gravitating gas. Under these conditions we find that the accretion reaches levels far in excess of the Eddington rate. A prediction of this scenario is that X-ray number counts of active galactic nuclei at z>6 would exhibit a cutoff at the low luminosities corresponding to black-hole masses below ~10^5 solar masses. At low redshifts we find photon trapping to be unimportant because it could only occur in rare low spin halos, and would require black-hole masses in excess of expectations from the observed black-hole - halo mass relation. The super-Eddington growth of ~10^5 solar mass seed black-holes at high redshift may have provided a natural acceleration towards the growth of super-massive black-holes at z~6-7, less than a billion years after the Big Bang.Comment: 10 pages, 4 figures. Submitted to MNRA

Cosmic Hydrogen Was Significantly Neutral a Billion Years After the Big Bang

The ionization fraction of cosmic hydrogen, left over from the big bang, provides crucial fossil evidence for when the first stars and quasar black holes formed in the infant universe. Spectra of the two most distant quasars known show nearly complete absorption of photons with wavelengths shorter than the Ly-alpha transition of neutral hydrogen, indicating that hydrogen in the intergalactic medium (IGM) had not been completely ionized at a redshift z~6.3, about a billion years after the big bang. Here we show that the radii of influence of ionizing radiation from these quasars imply that the surrounding IGM had a neutral hydrogen fraction of tens of percent prior to the quasar activity, much higher than previous lower limits of ~0.1%. When combined with the recent inference of a large cumulative optical depth to electron scattering after cosmological recombination from the WMAP data, our result suggests the existence of a second peak in the mean ionization history, potentially due to an early formation episode of the first stars.Comment: 14 Pages, 2 Figures. Accepted for publication in Nature. Press embargo until publishe

Delivery preferences for psychological intervention in cardiac rehabilitation : a pilot discrete choice experiment

BACKGROUND: Cardiac rehabilitation (CR) is a programme of care offered to people who recently experienced a cardiac event. There is a growing focus on home-based formats of CR and a lack of evidence on preferences for psychological care in CR. This pilot study aimed to investigate preferences for delivery attributes of a psychological therapy intervention in CR patients with symptoms of anxiety and/or depression. METHODS: A discrete choice experiment (DCE) was conducted and recruited participants from a feasibility trial. Participants were asked to choose between two hypothetical interventions, described using five attributes; intervention type (home or centre-based), information provided, therapy manual format, cost to the National Health Service (NHS) and waiting time. A separate opt-out was included. A conditional logit using maximum likelihood estimation was used to analyse preferences. The NHS cost was used to estimate willingness to pay for aspects of the intervention delivery. RESULTS: 35 responses were received (39% response rate). Results indicated that participants would prefer to receive any form of therapy compared with no therapy. Statistically significant results were limited, but included participants being keen to avoid not receiving information prior to therapy (β=-0.270; p=0.03) and preferring a lower cost to the NHS (β=-0.001; p=0.00). No significant results were identified for the type of psychological intervention, format of therapy/exercises and programme start time. Coefficients indicated preferences were stronger for home-based therapy compared with centre-based, but this was not significant. CONCLUSIONS: The pilot study demonstrates the feasibility of a DCE in this group, it identifies potential attributes and levels, and estimates the sample sizes needed for a full study. Preliminary evidence indicated that sampled participants tended to prefer home-based psychological therapy in CR and wanted to receive information before initiating therapy. Results are limited due to the pilot design and further research is needed

Cost-effectiveness of home-based cardiac rehabilitation : a systematic review

OBJECTIVE: Centre-based cardiac rehabilitation (CR) is recognised as cost-effective for individuals following a cardiac event. However, home-based alternatives are becoming increasingly popular, especially since COVID-19, which necessitated alternative modes of care delivery. This review aimed to assess whether home-based CR interventions are cost-effective (vs centre-based CR). METHODS: Using the MEDLINE, Embase and PsycINFO databases, literature searches were conducted in October 2021 to identify full economic evaluations (synthesising costs and effects). Studies were included if they focused on home-based elements of a CR programme or full home-based programmes. Data extraction and critical appraisal were completed using the NHS EED handbook, Consolidated Health Economic Evaluation Reporting Standards and Drummond checklists and were summarised narratively. The protocol was registered on the PROSPERO database (CRD42021286252). RESULTS: Nine studies were included in the review. Interventions were heterogeneous in terms of delivery, components of care and duration. Most studies were economic evaluations within clinical trials (8/9). All studies reported quality-adjusted life years, with the EQ-5D as the most common measure of health status (6/9 studies). Most studies (7/9 studies) concluded that home-based CR (added to or replacing centre-based CR) was cost-effective compared with centre-based options. CONCLUSIONS: Evidence suggests that home-based CR options are cost-effective. The limited size of the evidence base and heterogeneity in methods limits external validity. There were further limitations to the evidence base (eg, limited sample sizes) that increase uncertainty. Future research is needed to cover a greater range of home-based designs, including home-based options for psychological care, with greater sample sizes and the potential to acknowledge patient heterogeneity