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Investigating discrepancies in perceptions regarding the provision of hospital Rest and Relaxation spaces in Scotland during the COVID-19 pandemic and beyond : a qualitative study
Get PDFFunding: The work was originally supported by the Chief Scientist of Scotland Rapid COVID Grant Call (COV_ABN-20/06). Further funding was received from the SMERC Large Grant Programme.Objectives To investigate discrepancies in perceptions regarding the accessibility and availability of rest and relaxation (R&R) spaces between hospital doctors in Scotland and NHS Scotland regional health boards (HBs), with the intention of informing best practices for organisational policy on the provision of R&R spaces both now and in the future. Design A qualitative study, through an inhabited institutionalism (II) lens, of semi-structured interviews of hospital doctors across the career continuum in Scotland and all NHS regional HBs in Scotland providing written information relating to R&R space provision. Setting NHS Scotland during the COVID-19 pandemic and beyond. Participants Hospital doctors (n=30) who had participated in a larger qualitative study and provided specific insights on R&R spaces. All NHS Scotland regional HBs (n=14). Results Although HBs reported the provision of R&R spaces, numerous doctors reported R&R spaces had been removed, relocated or were inaccessible. Furthermore, limited awareness of their availability attributed to inadequate communication, compounded the issue. This divergence between institutional reporting and front-line experience can be interpreted through the lens of II, which posits that institutional polices are often interpreted and implemented differently. Conclusions This study emphasises how crucial R&R spaces are to promoting doctors’ well-being especially during the time of high stress. HBs must not only guarantee the accessibility and physical availability of R&R spaces but also enhance their communication regarding the provision.Peer reviewe
The politics of aesthetic autonomy in interwar Britain and mandatory Palestine, 1918-1939
No full textThis dissertation examines the intersection of aesthetic autonomy and self-determination between 1918 and 1939 in Britain and Mandatory Palestine. Challenging the conventional view of autonomy as an apolitical, solipsistic concern with the aesthetic, it argues that aesthetic autonomy, in its historical manifestations, was entwined with political concerns. During the interwar period, two key concepts of freedoms gained prominence in the political discourse—individual liberty and national self-determination. While British modernists interpreted autonomy as aligned with liberal democratic values, Jewish modernists in Mandatory Palestine engaged with it as a means of fostering national self-determination.
The first section focuses on abstract art in 1930s Britain, analysing its reception and production in relation to democratic values. Chapter one examines the debate in the 1930s British press about the political and social value of modern art, showing how aesthetic autonomy was framed in political terms, associated either with democratic ideals or with degeneration and cultural decline. Chapters two and three examine the abstract practices of Barbara Hepworth and Jessica Dismorr, demonstrating how each interpreted aesthetic autonomy in alignment with democratic freedoms, particularly personal autonomy and freedom of expression.
The second section turns to Jewish modernism in Mandatory Palestine to examine how aesthetic autonomy shaped cultural claims to national self-determination. It explores British-Jewish relationship and how modernists negotiated national self-determination within the cultural politics of the Mandate. Chapter four investigates British cultural policies and how imperial attitudes shaped official responses to Jewish art. Chapter five examines how Jewish modernists navigated this political landscape, interpreting autonomy to assert peoplehood."This research was financially supported by several grants: the Janet T. Anderson Scholarship, the Jewish Student Aid Trust, the Kenneth Lindsay Scholarship Trust, the Catherine and Alfred Forrest Trust, the Company of Arts, and the Paul Mellon Centre for Studies in British Art."--Fundin
Quasi-geostrophic vortex merger over bathymetry
Get PDFWe investigate interactions between two like-signed vortices over either an isolated seamount or a basin (a depression in the bathymetry), using a quasi-geostrophic, two-layer model on the -plane. When the vortex pair is centred over the seamount, the vortices are pushed together by the secondary flow generated in the bottom layer, facilitating their merger. Over a basin, the deep anomalies are much stronger and their interaction strains out the surface vortices. The results are supported by an analytical estimation of the initial potential vorticity anomalies in the lower layer and by analysis of the linear stability of a single vortex over the bathymetry. Similar phenomena are observed when the vortex pair is displaced from the bathymetric centre and when the initial vortices are initially compensated. Sub-deformation-scale vortices are less influenced by bathymetry than larger vortices. The results help explain asymmetries noted previously in turbulence simulations over bathymetry.Peer reviewe
Constraining the reflective properties of WASP-178 b using CHEOPS photometry
Get PDFFunding: CHEOPS is an ESA mission in partnership with Switzerland with important contributions to the payload and the ground segment from Austria, Belgium, France, Germany, Hungary, Italy, Portugal, Spain, Sweden, and the United Kingdom. The CHEOPS Consortium would like to gratefully acknowledge the support received by all the agencies, offices, universities, and industries involved. Their flexibility and willingness to explore new approaches were essential to the success of this mission. IPa, GSc, VSi, LBo, GBr, VNa, GPi, and RRa acknowledge support from CHEOPS ASI-INAF agreement no. 2019-29-HH.0. ML acknowledges support of the Swiss National Science Foundation under grant number PCEFP2_194576. This work was also partially supported by a grant from the Simons Foundation (PI Queloz, grant number 327127). S.G.S. acknowledges support from FCT through FCT contract nr. CEECIND/00826/2018 and POPH/FSE (EC). ABr was supported by the SNSA. ACCa and TWi acknowledge support from STFC consolidated grant numbers ST/R000824/1 and ST/V000861/1, and UKSA grant number ST/R003203/1. V.V.G. is an F.R.S-FNRS Research Associate. Y.Al. acknowledges support from the Swiss National Science Foundation (SNSF) under grant 200020_192038. We acknowledge support from the Spanish Ministry of Science and Innovation and the European Regional Development Fund through grants ESP2016-80435-C2-1-R, ESP2016-80435-C2-2-R, PGC2018-098153-B-C33, PGC2018-098153-B-C31, ESP2017-87676-C5-1-R, MDM-2017-0737 Unidad de Excelencia Maria de Maeztu-Centro de Astrobiología (INTACSIC), as well as the support of the Generalitat de Catalunya/CERCA programme. The MOC activities have been supported by the ESA contract No. 4000124370. S.C.C.B. acknowledges support from FCT through FCT contracts nr. IF/01312/2014/CP1215/CT0004. X.B., S.C., D.G., M.F. and J.L. acknowledge their role as ESA-appointed CHEOPS science team members. This project was supported by the CNES. The Belgian participation to CHEOPS has been supported by the Belgian Federal Science Policy Office (BELSPO) in the framework of the PRODEX Program, and by the University of Liège through an ARC grant for Concerted Research Actions financed by the Wallonia-Brussels Federation. L.D. is an F.R.S.-FNRS Postdoctoral Researcher. This work was supported by FCT - Fundação para a Ciência e a Tecnologia through national funds and by FEDER through COMPETE2020 - Programa Operacional Competitividade e Internacionalizacão by these grants: UID/FIS/04434/2019, UIDB/04434/2020, UIDP/04434/2020, PTDC/FIS-AST/32113/2017 & POCI-01-0145-FEDER-032113, PTDC/FIS-AST/28953/2017 & POCI-01-0145-FEDER-028953, PTDC/FIS-AST/28987/2017 & POCI-01-0145-FEDER-028987, O.D.S.D. is supported in the form of work contract (DL 57/2016/CP1364/CT0004) funded by national funds through FCT. B.-O.D. acknowledges support from the Swiss State Secretariat for Education, Research and Innovation (SERI) under contract number MB22.00046. This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research grant agreement no. 724427). It has also been carried out in the frame of the National Centre for Competence in Research PlanetS supported by the Swiss National Science Foundation (SNSF). D.E. acknowledges financial support from the Swiss National Science Foundation for project 200021_200726 and innovation programme (project FOUR ACES). M.F. and C.M.P. gratefully acknowledge the support of the Swedish National Space Agency (DNR 65/19, 174/18). D.G. gratefully acknowledges financial support from the CRT foundation under Grant No. 2018.2323 "Gaseousor rocky? Unveiling the nature of small worlds". M.G. is an F.R.S.-FNRS Senior Research Associate. M.N.G. is the ESA CHEOPS Project Scientist and Mission Representative, and as such also responsible for the Guest Observers (GO) Programme. M.N.G. does not relay proprietary information between the GO and Guaranteed Time Observation (GTO) Programmes, and does not decide on the definition and target selection of the GTO Programme. SH gratefully acknowledges CNES funding through the grant 837319. K.G.I. is the ESA CHEOPS Project Scientist and is responsible for the ESA CHEOPS Guest Observers Programme. She does not participate in, or contribute to, the definition of the Guaranteed Time Programme of the CHEOPS mission through which observations described in this paper have been taken, nor to any aspect of target selection for the programme. This work was granted access to the HPC resources of MesoPSL financed by the Region Ile de France and the project Equip@Meso (reference ANR-10-EQPX-29-01) of the programme Investissements d'Avenir supervised by the Agence Nationale pour la Recherche. P.M. acknowledges support from STFC research grant number ST/M001040/1. I.R.I. acknowledges support from the Spanish Ministry of Science and Innovation and the European Regional Development Fund through grant PGC2018-098153-B-C33, as well as the support of the Generalitat de Catalunya/CERCA programme. Gy.M.Sz. acknowledges the support of the Hungarian National Research, Development and Innovation Office (NKFIH) grant K-125015, a PRODEX Experiment Agreement No. 4000137122, the Lendület LP2018-7/2021 grant of the Hungarian Academy of Science and the support of the city of Szombathely. N.A.W. acknowledges UKSA grant ST/R004838/1. N.C.S. acknowledges funding by the European Union (ERC, FIERCE, 101052347). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Research Council. Neither the European Union nor the granting authority can be held responsible for them. K.W.F.L. was supported by Deutsche Forschungsgemeinschaft grants RA714/14-1 within the DFG Schwerpunkt SPP 1992, Exploring the Diversity of Extrasolar Planets. In this work, we use the python package PyDE available at https://github.com/hpparvi/PyDE. This research has made use of the SVO Filter Profile Service (http://svo2.cab.inta-csic.es/theory/fps/) supported from the Spanish MINECO through grant AYA2017-84089. We thank the referee, N. B. Cowan, for his valuable comments and suggestions. CHEOPS is an ESA mission in partnership with Switzerland with important contributions to the payload and the ground segment from Austria, Belgium, France, Germany, Hungary, Italy, Portugal, Spain, Sweden, and the United Kingdom. The CHEOPS Consortium would like to gratefully acknowledge the support received by all the agencies, offices, universities, and industries involved. Their flexibility and willingness to explore new approaches were essential to the success of this mission. IPa, GSc, VSi, LBo, GBr, VNa, GPi, and RRa acknowledge support from CHEOPS ASI-INAF agreement no. 2019-29-HH.0. ML acknowledges support of the Swiss National Science Foundation under grant number PCEFP2_194576. This work was also partially supported by a grant from the Simons Foundation (PI Queloz, grant number 327127). S.G.S. acknowledges support from FCT through FCT contract nr. CEECIND/00826/2018 and POPH/FSE (EC). ABr was supported by the SNSA. ACCa and TWi acknowledge support from STFC consolidated grant numbers ST/R000824/1 and ST/V000861/1, and UKSA grant number ST/R003203/1. V.V.G. is an F.R.S-FNRS Research Associate. Y.Al. acknowledges support from the Swiss National Science Foundation (SNSF) under grant 200020_192038. We acknowledge support from the Spanish Ministry of Science and Innovation and the European Regional Development Fund through grants ESP2016-80435-C2-1-R, ESP2016-80435-C2-2-R, PGC2018-098153-B-C33, PGC2018-098153-B-C31, ESP2017-87676-C5-1-R, MDM-2017-0737 Unidad de Excelencia Maria de Maeztu-Centro de Astrobiología (INTA-CSIC), as well as the support of the Generalitat de Catalunya/CERCA programme. The MOC activities have been supported by the ESA contract No. 4000124370. S.C.C.B. acknowledges support from FCT through FCT contracts nr. IF/01312/2014/CP1215/CT0004. X.B., S.C., D.G., M.F. and J.L. acknowledge their role as ESA-appointed CHEOPS science team members. This project was supported by the CNES. The Belgian participation to CHEOPS has been supported by the Belgian Federal Science Policy Office (BELSPO) in the framework of the PRODEX Program, and by the University of Liège through an ARC grant for Concerted Research Actions financed by the Wallonia-Brussels Federation. L.D. is an F.R.S.-FNRS Postdoctoral Researcher. This work was supported by FCT – Fundação para a Ciência e a Tecnologia through national funds and by FEDER through COMPETE2020 – Programa Operacional Competitividade e Internacionalizacão by these grants: UID/FIS/04434/2019, UIDB/04434/2020, UIDP/04434/2020, PTDC/FIS-AST/32113/2017 & POCI-01-0145-FEDER-032113, PTDC/FIS-AST/28953/2017 & POCI-01-0145-FEDER-028953, PTDC/FIS-AST/28987/2017 & POCI-01-0145-FEDER-028987, O.D.S.D. is supported in the form of work contract (DL 57/2016/CP1364/CT0004) funded by national funds through FCT. B.-O.D. acknowledges support from the Swiss State Secretariat for Education, Research and Innovation (SERI) under contract number MB22.00046. This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research grant agreement no. 724427). It has also been carried out in the frame of the National Centre for Competence in Research PlanetS supported by the Swiss National Science Foundation (SNSF). D.E. acknowledges financial support from the Swiss National Science Foundation for project 200021_200726 and innovation programme (project F OUR A CES ). M.F. and C.M.P. gratefully acknowledge the support of the Swedish National Space Agency (DNR 65/19, 174/18). D.G. gratefully acknowledges financial support from the CRT foundation under Grant No. 2018.2323 “Gaseousor rocky? Unveiling the nature of small worlds”. M.G. is an F.R.S.-FNRS Senior Research Associate. M.N.G. is the ESA CHEOPS Project Scientist and Mission Representative, and as such also responsible for the Guest Observers (GO) Programme. M.N.G. does not relay proprietary information between the GO and Guaranteed Time Observation (GTO) Programmes, and does not decide on the definition and target selection of the GTO Programme. SH gratefully acknowledges CNES funding through the grant 837319. K.G.I. is the ESA CHEOPS Project Scientist and is responsible for the ESA CHEOPS Guest Observers Programme. She does not participate in, or contribute to, the definition of the Guaranteed Time Programme of the CHEOPS mission through which observations described in this paper have been taken, nor to any aspect of target selection for the programme. This work was granted access to the HPC resources of MesoPSL financed by the Region Ile de France and the project Equip@Meso (reference ANR-10-EQPX-29-01) of the programme Investissements d’Avenir supervised by the Agence Nationale pour la Recherche. P.M. acknowledges support from STFC research grant number ST/M001040/1. I.R.I. acknowledges support from the Spanish Ministry of Science and Innovation and the European Regional Development Fund through grant PGC2018-098153-B-C33, as well as the support of the Generalitat de Catalunya/CERCA programme. Gy.M.Sz. acknowledges the support of the Hungarian National Research, Development and Innovation Office (NKFIH) grant K-125015, a PRODEX Experiment Agreement No. 4000137122, the Lendület LP2018-7/2021 grant of the Hungarian Academy of Science and the support of the city of Szombathely. N.A.W. acknowledges UKSA grant ST/R004838/1. N.C.S. acknowledges funding by the European Union (ERC, FIERCE, 101052347). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Research Council. Neither the European Union nor the granting authority can be held responsible for them. K.W.F.L. was supported by Deutsche Forschungsgemeinschaft grants RA714/14-1 within the DFG Schwerpunkt SPP 1992, Exploring the Diversity of Extrasolar Planets. In this work, we use the python package PyDE available at https://github.com/hpparvi/PyDE . This research has made use of the SVO Filter Profile Service ( http://svo2.cab.inta-csic.es/theory/fps/ ) supported from the Spanish MINECO through grant AYA2017-84089.Context . Multiwavelength photometry of the secondary eclipses of extrasolar planets is able to disentangle the reflected and thermally emitted light radiated from the planetary dayside. Based on this, we can measure the planetary geometric albedo Ag, which is an indicator of the presence of clouds in the atmosphere, and the recirculation efficiency ϵ, which quantifies the energy transport within the atmosphere. Aims . We measure Ag and ϵ for the planet WASP-178 b, a highly irradiated giant planet with an estimated equilibrium temperature of 2450 K. Methods . We analyzed archival spectra and the light curves collected by CHEOPS and TESS to characterize the host WASP-178, refine the ephemeris of the system, and measure the eclipse depth in the passbands of the two telescopes. Results. We measured a marginally significant eclipse depth of 70 ± 40 ppm in the TESS passband, and a statistically significant depth of 70 ± 20 ppm in the CHEOPS passband. Conclusions . Combining the eclipse-depth measurement in the CHEOPS (λeff = 6300 Å) and TESS (λeff = 8000 Å) passbands, we constrained the dayside brightness temperature of WASP-178 b in the 2250-2800 K interval. The geometric albedo 0.10.7 makes WASP-178 b an interesting laboratory for testing the current heat-recirculation models.Peer reviewe
Education towards a reasonable humanism
Get PDFEducation is twice over concerned with human nature, most extensively as it is presupposed in the pursuit of diverse aims, and more specifically, as understanding it and applying such understanding are themselves made objects of study and teaching. The latter was a principal concern of ancient, renaissance and enlightenment humanists. These and others who focussed on the human condition have tended to arrive at one of the three attitudes: the celebratory, the gloomy and the condemnatory. Recent decades have seen tyrannies, global wars, campaigns of genocide, economic crises, seemingly irreconcilable political polarisation, man-made environmental degradation and other evils. Besides posing practical challenges, these put in question ideas of historical progress, of social harmony and of personal flourishing, and thereby have implications for an understanding of the human condition and for what to teach concerning it, and what qualities of character to seek to inculcate.Peer reviewe
Antimicrobial resistance burden estimates from the bottom-up : research priorities for estimating the impact of antimicrobial resistance in Brazil
Get PDFFunding: KK was funded by a 3-month Visiting Professor award from the Brazilian Federal Agency for Support and Evaluation of Graduate Education (CAPES) (88887.900085/2023-00). EC is also an employee of Sanofi. JSC was funded by a fellowship provided by CNPQ (151272/2023-9) and The State of São Paulo Research Foundation (FAPESP) (2023/09515-5). This work was supported by the Sao Paulo Research Foundation-funded ARIES Project (FAPESP Grant 2021/10599-3).Recent estimates of deaths attributable to bacterial antimicrobial resistance (AMR) highlight the immense public health threat of AMR to healthcare systems, economies, and communities in Latin America. Although global modelling studies generate important statistics to motivate and guide global and national agendas, their complex methodology and aggregation mean that they have a more limited impact at the local scales where AMR is experienced and tackled. At the same time, it is increasingly recognised that we need to study and design AMR policies ‘from the bottom-up’, drawing on data and perspectives that ensure local ownership of the research and policy agenda. But how do we integrate ‘bottom-up’ perspectives into AMR burden estimation? Brazil is used as a case study to illustrate the importance of this approach. Brazil's vast and decentralised healthcare system would benefit from robust regional estimates of AMR's clinical, economic, and social burdens to move political decision-making and design appropriate interventions. We report on recommendations gathered from interdisciplinary stakeholder exercises and propose strategic priorities for estimating the AMR burden in Brazil at subnational scales of governance. These include focusing on individual-level data linkages at various scales; capturing public and private healthcare systems; understanding AMR inequalities; and capturing linked clinical, economic, and social burdens.Peer reviewe
Optimizing flexible zeolite Rho for unrivalled argon purification
Get PDFFunding: The authors thank the EPSRC for (FLEXICCS–Flexible Industrial Carbon Capture (EP/N024613/1; M.M.L. and P.A.W.), CationControlled Gating for Selective Gas Adsorption over Adaptable Zeo lites (EP/N032942/1; PAW and VMG) for funding and an NPIF PhD scholarship for ELB: EP/R512199/1). Experiments at the ISIS Neutron and Muon Source were supported by beamtime allocations RB1820563 and XB1890041 from the Science and Technology Facilities Council. Dr Alessandro Turrina (Johnson Matthey Technology Centre) is thanked for providing as-prepared Na,Cs-Rho material. Dr Julia L. Payne (University of St. Andrews) is thanked for assistance with sample preparation for NPD analysis. The authors acknowledge the SEM-EDS spectroscopy equipment funding (EPSRC Light Element Analysis Facility Grant: EP/ T019298/1).The preparation of pure Ar from air requires removal of O2 from a crude Ar stream produced by cryogenic distillation. Whereas their similar boiling points make further separation by distillation expensive, the difference in their molecular sizes makes separation by flexible zeolites an attractive route to kinetic separation. Modifying the cation content of the flexible and cubic zeolite Rho enables precise tuning of a single window size for unprecedented kinetic separation of O2 from Ar. Li-Rho (unit cell Li9.8Al9.8Si38.2O96) is a very selective adsorbent due to its small pore size, but the highly distorted framework results in very slow O2 diffusion. By replacing some of the Li+ with H+, Cs+, or Zn2+, the window can be enlarged and in some cases the window cation occupancy reduced, increasing O2 diffusion rates whilst retaining high O2/Ar selectivity. The optimum unit cell composition among those examined was found to be Li6.2Zn1.8-Rho (O2/Ar selectivity = 813, D/r2(O2) = 0.37 s-1).Peer reviewe
The K2-24 planetary system revisited by CHEOPS
Get PDFFunding: ACC acknowledges support from STFC consolidated grant number ST/V000861/1, and UKSA grant number ST/X002217/1. TWi acknowledges support from the UKSA and the University of Warwick. CHe acknowledges support from the European Union H2020-MSCA-ITN-2019 under Grant Agreement no. 860470 (CHAMELEON). PM acknowledges support from STFC research grant number ST/R000638/1. NCSa acknowledges funding by the European Union (ERC, FIERCE, 101052347). NAW acknowledges UKSA grant ST/R004838/1.The planetary system K2-24 is composed of two transiting low-density Neptunians locked in an almost perfect 2:1 resonance and showing large transit time variations (TTVs), and it is an excellent laboratory to search for signatures of planetary migration. Previous studies performed with K2, Spitzer, and RV data tentatively claimed a significant non-zero eccentricity for one or both planets, possibly high enough to challenge the scenario of pure disk migration through resonant capture. With 13 new CHEOPS light curves (seven of planet b, six of planet c), we carried out a global photometric and dynamical re-analysis by including all the available literature data as well. We obtained the most accurate set of planetary parameters to date for the K2-24 system, including radii and masses at 1% and 5% precision (now essentially limited by the uncertainty on stellar parameters) and non-zero eccentricities eb = 0.0498−0.0018+0.0011, ec = 0.0282−0.0007+0.0003 detected at very high significance for both planets. Such relatively large values imply the need for an additional physical mechanism of eccentricity excitation during or after the migration stage. Also, while the accuracy of the previous TTV model had drifted by up to 0.5 days at the current time, we constrained the orbital solution firmly enough to predict the forthcoming transits for the next ~15 years, thus enabling efficient follow-up with top-level facilities such as JWST or ESPRESSO.Peer reviewe
Heights of one- and two-sided congruence lattices of semigroups
Get PDFFunding: Supported by the Engineering and Physical Sciences Research Council [EP/S020616/1, EP/V002953/1 and EP/V003224/1] and the Australian Research Council [FT190100632].The height of a poset P is the supremum of the cardinalities of chains in P. The exact formula for the height of the subgroup lattice of the symmetric group Sn is known, as is an accurate asymptotic formula for the height of the subsemigroup lattice of the full transformation monoid Tn. Motivated by the related question of determining the heights of the lattices of left and right congruences of Tn, and deploying the framework of unary algebras and semigroup actions, we develop a general method for computing the heights of lattices of both one- and two-sided congruences for semigroups. We apply this theory to obtain exact height formulae for several monoids of transformations, matrices and partitions, including the full transformation monoid Tn, the partial transformation monoid PTn, the symmetric inverse monoid In, the monoid of order-preserving transformations On, the full matrix monoid M(n, q), the partition monoid Pn, the Brauer monoid Bnand the Temperley–Lieb monoid T Ln.Peer reviewe
Characterisation of the TOI-421 planetary system using CHEOPS, TESS, and archival radial velocity data
Get PDFFunding: ACC acknowledge support from STFC consolidated grant numbers ST/R000824/1 and ST/V000861/1, and UKSA grant number ST/R003203/1. This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (project FOUR ACES. grant agreement no. 724427). CHe acknowledges support from the European Union H2020-MSCA-ITN-2019 under Grant Agreement no. 860470 (CHAMELEON). P.M. acknowledges support from STFC research grant number ST/M001040/1. NCSa acknowledges funding by the European Union (ERC, FIERCE, 101052347). N.A.W. acknowledges UKSA grant ST/R004838/1.Context. The TOI-421 planetary system contains two sub-Neptune-type planets (Pb ~ 5.2 days, Teq,b ~ 900 K, and Pc ~ 16.1 days, Teq,c ~ 650 K) and is a prime target to study the formation and evolution of planets and their atmospheres. The inner planet is especially interesting as the existence of a hydrogen-dominated atmosphere at its orbital separation cannot be explained by current formation models without previous orbital migration. Aims. We aim to improve the system parameters to further use them to model the interior structure and simulate the atmospheric evolution of both planets, to finally gain insights into their formation and evolution. We also investigate the possibility of detecting transit timing variations (TTVs). Methods. We jointly analysed photometric data of three TESS sectors and six CHEOPS visits as well as 156 radial velocity data points to retrieve improved planetary parameters. We also searched for TTVs and modelled the interior structure of the planets. Finally, we simulated the evolution of the primordial H-He atmospheres of the planets using two different modelling frameworks. Results. We determine the planetary radii and masses of TOI-421 b and c to be Rb = 2.64 ± 0.08 R⊕, Mb = 6.7 ± 0.6 M⊕, Rc = 5.09 ± 0.07 R⊕, and Mc = 14.1 ± 1.4 M⊕. Using these results we retrieved average planetary densities of ρb = 0.37 ± 0.05ρ⊕ and ρc = 0.107 ± 0.012 ρ⊕. We do not detect any statistically significant TTV signals. Assuming the presence of a hydrogen-dominated atmosphere, the interior structure modelling results in both planets having extensive envelopes. While the modelling of the atmospheric evolution predicts for TOI-421 b to have lost any primordial atmosphere that it could have accreted at its current orbital position, TOI-421 c could have started out with an initial atmospheric mass fraction somewhere between 10 and 35%. Conclusions. We conclude that the low observed mean density of TOI-421 b can only be explained by either a bias in the measured planetary parameters (e.g. driven by high-altitude clouds) and/or in the context of orbital migration. We also find that the results of atmospheric evolution models are strongly dependent on the employed planetary structure model.Peer reviewe
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