550 research outputs found
Exploring the climate of Proxima B with the Met Office Unified Model
This is the author accepted manuscript. The final version is available from EDP Sciences via the DOI in this record.The corrigendum to this article is in ORE at: http://hdl.handle.net/10871/34331We present results of simulations of the climate of the newly discovered planet Proxima Centauri B, performed using the Met Office
Unified Model (UM). We examine the responses of both an ‘Earth-like’ atmosphere and simplified nitrogen and trace carbon dioxide
atmosphere to the radiation likely received by Proxima Centauri B. Additionally, we explore the effects of orbital eccentricity on the
planetary conditions using a range of eccentricities guided by the observational constraints. Overall, our results are in agreement with
previous studies in suggesting Proxima Centauri B may well have surface temperatures conducive to the presence of liquid water.
Moreover, we have expanded the parameter regime over which the planet may support liquid water to higher values of eccentricity
(& 0.1) and lower incident fluxes (881.7 W m−2
) than previous work. This increased parameter space arises because of the low
sensitivity of the planet to changes in stellar flux, a consequence of the stellar spectrum and orbital configuration. However, we also
find interesting differences from previous simulations, such as cooler mean surface temperatures for the tidally-locked case. Finally,
we have produced high resolution planetary emission and reflectance spectra, and highlight signatures of gases vital to the evolution
of complex life on Earth (oxygen, ozone and carbon dioxide).I.B., J.M. and P.E. acknowledge the support of a Met Office Academic Partnership secondment. B.D. thanks the University of Exeter for
support through a Ph.D. studentship. N.J.M. and J.G.’s contributions were in part
funded by a Leverhulme Trust Research Project Grant, and in part by a University
of Exeter College of Engineering, Mathematics and Physical Sciences studentship.
We acknowledge use of the MONSooN system, a collaborative facility
supplied under the Joint Weather and Climate Research Programme, a strategic
partnership between the Met Office and the Natural Environment Research
Council. This work also used the University of Exeter Supercomputer, a DiRAC
Facility jointly funded by STFC, the Large Facilities Capital Fund of BIS and
the University of Exeter
The effect of metallicity on the atmospheres of exoplanets with fully coupled 3D hydrodynamics, equilibrium chemistry, and radiative transfer (article)
This is the author accepted manuscript. The final version is available from EDP Sciences for European Southern Observatory (ESO) via the DOI in this record.The dataset associated with this article is located in ORE at: http://hdl.handle.net/10871/32593In this work we have performed a series of simulations of the atmosphere of GJ 1214b assuming different metallicities
using the Met Office Unified Model (UM). The UM is a general circulation model (GCM) that solves the deep, nonhydrostatic
equations of motion and uses a flexible and accurate radiative transfer scheme, based on the two-stream
and correlated-k approximations, to calculate the heating rates. In this work we consistently couple a well-tested
Gibbs energy minimisation scheme to solve for the chemical equilibrium abundances locally in each grid cell for a
general set of elemental abundances, further improving the flexibility and accuracy of the model. As the metallicity
of the atmosphere is increased we find significant changes in the dynamical and thermal structure, with subsequent
implications for the simulated phase curve. The trends that we find are qualitatively consistent with previous works,
though with quantitative differences. We investigate in detail the effect of increasing the metallicity by splitting the
mechanism into constituents, involving the mean molecular weight, the heat capacity and the opacities. We find the
opacity effect to be the dominant mechanism in altering the circulation and thermal structure. This result highlights
the importance of accurately computing the opacities and radiative transfer in 3D GCMs.This work is partly supported by the European
Research Council under the European Community’s Seventh
Framework Programme (FP7/2007-2013 Grant Agreement No.
247060-PEPS and grant No. 320478-TOFU). BD acknowledges funding
from the European Research Council (ERC) under the European
Unions Seventh Framework Programme (FP7/2007-2013) / ERC
grant agreement no. 336792 and thanks the University of Exeter for
support through a PhD studentship. DSA acknowledges support from
the NASA Astrobiology Program through the Nexus for Exoplanet
System Science. NJM and JG’s contributions were in part funded by
a Leverhulme Trust Research Project Grant, and in part by a University
of Exeter College of Engineering, Mathematics and Physical
Sciences studentship. This work used the DiRAC Complexity system,
operated by the University of Leicester IT Services, which forms
part of the STFC DiRAC HPC Facility. This equipment is funded
by BIS National E-Infrastructure capital grant ST/K000373/1 and
STFC DiRAC Operations grant ST/K0003259/1. DiRAC is part of
the National E-Infrastructure. This work also used the University of
Exeter Supercomputer, a DiRAC Facility jointly funded by STFC,
the Large Facilities Capital Fund of BIS and the University of Exeter.
Material produced using Met Office Software
Yangian in the Twistor String
We study symmetries of the quantized open twistor string. In addition to
global PSL(4|4) symmetry, we find non-local conserved currents. The associated
non-local charges lead to Ward identities which show that these charges
annihilate the string gluon tree amplitudes, and have the same form as
symmetries of amplitudes in N=4 super conformal Yang Mills theory. We describe
how states of the open twistor string form a realization of the PSL(4|4)
Yangian superalgebra.Comment: 37 pages, 4 figure
The Limits of the Primitive Equations of Dynamics for Warm, Slowly Rotating Small Neptunes and Super Earths (article)
This is the author accepted manuscript. The final version is available from American Astronomical Society / IOP Publishing via the DOI in this record.The dataset associated with this article is located in ORE at: https://doi.org/10.24378/exe.1023We present significant differences in the simulated atmospheric flow for warm, tidally-locked small
Neptunes and super Earths (based on a nominal GJ 1214b) when solving the simplified, and commonly
used, primitive dynamical equations or the full Navier-Stokes equations. The dominant prograde,
superrotating zonal jet is markedly different between the simulations which are performed using practically identical numerical setups, within the same model. The differences arise due to the breakdown of the so-called `shallow-fluid' and traditional approximations, which worsens when rotation rates are slowed, and day{night temperature contrasts are increased. The changes in the zonal advection between simulations solving the full and simplified equations, give rise to significant differences in the atmospheric redistribution of heat, altering the position of the hottest part of the atmosphere and temperature contrast between the day and night sides. The implications for the atmospheric chemistry and, therefore, observations need to be studied with a model including a more detailed treatment of
the radiative transfer and chemistry. Small Neptunes and super Earths are extremely abundant and
important, potentially bridging the structural properties (mass, radius, composition) of terrestrial and
gas giant planets. Our results indicate care is required when interpreting the output of models solving
the primitive equations of motion for such planets.Leverhulme TrustScience and Technology Facilities CouncilEuropean Research Counci
Engineering synucleinopathy‐resistant human dopaminergic neurons by CRISPR‐mediated deletion of the SNCA gene
An emerging treatment for Parkinson's disease (PD) is cell replacement therapy. Authentic midbrain dopaminergic (mDA) neuronal precursors can be differentiated from human embryonic stem cells (hESCs) and human induced pluripotent stem cells (iPSCs). These laboratory‐generated mDA cells have been demonstrated to mature into functional dopaminergic neurons upon transplantation into preclinical models of PD. However, clinical trials with human fetal mesenchephalic cells have shown that cell replacement grafts in PD are susceptible to Lewy body formation suggesting host‐to‐graft transfer of α‐synuclein pathology. Here, we have used CRISPR/Cas9n technology to delete the endogenous SNCA gene, encoding for α‐synuclein, in a clinical‐grade hESC line to generate SNCA+/− and SNCA−/− cell lines. These hESC lines were first differentiated into mDA neurons, and then challenged with recombinant α‐synuclein preformed fibrils (PFFs) to seed the formation for Lewy‐like pathology as measured by phosphorylation of serine‐129 of α‐synuclein (pS129‐αSyn). Wild‐type neurons were fully susceptible to the formation of protein aggregates positive for pS129‐αSyn, while SNCA+/− and SNCA−/− neurons exhibited significant resistance to the formation of this pathological mark. This work demonstrates that reducing or completely removing SNCA alleles by CRISPR/Cas9n‐mediated gene editing confers a measure of resistance to Lewy pathology
Economics methods in Cochrane systematic reviews of health promotion and public health related interventions.
Peer reviewedPublisher PD
Observable signatures of wind-driven chemistry with a fully consistent three dimensional radiative hydrodynamics model of HD 209458b (article)
This is the final version of the article. Available from American Astronomical Society / IOP Publishing via the DOI in this record.The dataset associated with this article is located in ORE at: http://hdl.handle.net/10871/32579We present a study of the effect of wind-driven advection on the chemical composition of hot Jupiter
atmospheres using a fully-consistent 3D hydrodynamics, chemistry and radiative transfer code, the
Met Office Unified Model (UM). Chemical modelling of exoplanet atmospheres has primarily been
restricted to 1D models that cannot account for 3D dynamical processes. In this work we couple a
chemical relaxation scheme to the UM to account for the chemical interconversion of methane and
carbon monoxide. This is done consistently with the radiative transfer meaning that departures
from chemical equilibrium are included in the heating rates (and emission) and hence complete
the feedback between the dynamics, thermal structure and chemical composition. In this letter we
simulate the well studied atmosphere of HD 209458b. We find that the combined effect of horizontal
and vertical advection leads to an increase in the methane abundance by several orders of magnitude;
directly opposite to the trend found in previous works. Our results demonstrate the need to include
3D effects when considering the chemistry of hot Jupiter atmospheres. We calculate transmission
and emission spectra, as well as the emission phase curve, from our simulations. We conclude that
gas-phase non-equilibrium chemistry is unlikely to explain the model–observation discrepancy in the
4.5 µm Spitzer/IRAC channel. However, we highlight other spectral regions, observable with the
James Webb Space Telescope, where signatures of wind-driven chemistry are more prominent.BD and DKS acknowledge funding from the European
Research Council (ERC) under the European
Unions Seventh Framework Programme
(FP7/2007-2013) / ERC grant agreement no.
336792. NJM is part funded by a Leverhulme
Trust Research Project Grant. JM and IAB
acknowledge the support of a Met Office Academic
Partnership secondment. ALC is funded
by an STFC studentship. DSA acknowledges
support from the NASA Astrobiology Program
through the Nexus for Exoplanet System Science.
This work used the DiRAC Complexity
system, operated by the University of Leicester
IT Services, which forms part of the STFC
DiRAC HPC Facility. This equipment is funded
by BIS National E-Infrastructure capital grant
ST/K000373/1 and STFC DiRAC Operations
grant ST/K0003259/1. DiRAC is part of the
National E-Infrastructure
Linked randomised controlled trials of face-to-face and electronic brief intervention methods to prevent alcohol related harm in young people aged 14–17 years presenting to Emergency Departments (SIPS junior)
Background: Alcohol is a major global threat to public health. Although the main burden of chronic alcohol-related disease is in adults, its foundations often lie in adolescence. Alcohol consumption and related harm increase steeply from the age of 12 until 20 years. Several trials focusing upon young people have reported significant positive effects of brief interventions on a range of alcohol consumption outcomes. A recent review of reviews also suggests that electronic brief interventions (eBIs) using internet and smartphone technologies may markedly reduce alcohol consumption compared with minimal or no intervention controls.
Interventions that target non-drinking youth are known to delay the onset of drinking behaviours. Web based alcohol interventions for adolescents also demonstrate significantly greater reductions in consumption and harm among ‘high-risk’ drinkers; however changes in risk status at follow-up for non-drinkers or low-risk
drinkers have not been assessed in controlled trials of brief alcohol interventions
UK survey of occupational therapist’s and physiotherapist’s experiences and attitudes towards hip replacement precautions and equipment
Background: Total hip replacement (THR) is one of the most common orthopaedic procedures in the United Kingdom (UK). Historically, people following THR have been provided with hip precautions and equipment such as: raised toilet seats and furniture rises, in order to reduce the risks of dislocation post-operation. The purpose of this study was to determine current practices in the provision of these interventions in the UK for people following primary THR. Methods: A 27-question, self-administered online survey was developed and distributed to UK physiotherapists and occupational therapists involved in the management of people following primary THR (target respondents). The survey included questions regarding the current practices in the provision of equipment and hip precautions for THR patients, and physiotherapist’s and occupational therapist’s attitudes towards these practices. The survey was disseminated through print and web-based/social media channels. Results: 170 health professionals (87 physiotherapists and 83 occupational therapists), responded to the survey. Commonly prescribed equipment in respondent’s health trusts were raised toilet seats (95%), toilet frames and rails (88%), furniture raises (79%), helping hands/grabbers (77%), perching stools (75%) and long-handled shoe horns (75%). Hip precautions were routinely prescribed by 97% of respondents. Hip precautions were most frequently taught in a pre-operative group (52% of respondents). Similarly equipment was most frequently provided pre-operatively (61% respondents), and most commonly by occupational therapists (74% respondents). There was variability in the advice provided on the duration of hip precautions and equipment from up to six weeks post-operatively to life-time usage. Conclusions: Current practice on hip precautions and provision of equipment is not full representative of clinician’s perceptions of best care after THR. Future research is warranted to determine whether and to whom hip precautions and equipment should be prescribed post-THR as opposed to the current ‘blanket’ provision of equipment and movement restriction provided in UK practice
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British Thoracic Society Clinical Statement on pulmonary rehabilitation
Copyright © Author(s) (or their employer(s)) 2023. No commercial re-use. See rights and permissions. Published by BMJ.Linked Article: Editorial: Pulmonary rehabilitation marches on: refining, optimising and delivering through the clinical statement,
Charlotte E. Bolton, Thorax 2023; 78 (Suppl. 5), pp. s1-s1 Published Online First: 08 Nov 2023. DOI URL: https://doi.org/10.1136/thorax-2023-220581 .The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors
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