In--out intermittency in PDE and ODE models

We find concrete evidence for a recently discovered form of intermittency, referred to as in--out intermittency, in both PDE and ODE models of mean field dynamos. This type of intermittency (introduced in Ashwin et al 1999) occurs in systems with invariant submanifolds and, as opposed to on--off intermittency which can also occur in skew product systems, it requires an absence of skew product structure. By this we mean that the dynamics on the attractor intermittent to the invariant manifold cannot be expressed simply as the dynamics on the invariant subspace forcing the transverse dynamics; the transverse dynamics will alter that tangential to the invariant subspace when one is far enough away from the invariant manifold. Since general systems with invariant submanifolds are not likely to have skew product structure, this type of behaviour may be of physical relevance in a variety of dynamical settings. The models employed here to demonstrate in--out intermittency are axisymmetric mean--field dynamo models which are often used to study the observed large scale magnetic variability in the Sun and solar-type stars. The occurrence of this type of intermittency in such models may be of interest in understanding some aspects of such variabilities.Comment: To be published in Chaos, June 2001, also available at http://www.eurico.web.co

Integration of radiation oncology teaching in medical studies by German medical faculties due to the new licensing regulations: an overview and recommendations of the consortium academic radiation oncology of the German Society for Radiation Oncology (DEGRO)

The new Medical Licensing Regulations 2025 (Ärztliche Approbationsordnung, ÄApprO) will soon be passed by the Federal Council (Bundesrat) and will be implemented step by step by the individual faculties in the coming months. The further development of medical studies essentially involves an orientation from fact-based to competence-based learning and focuses on practical, longitudinal and interdisciplinary training. Radiation oncology and radiation therapy are important components of therapeutic oncology and are of great importance for public health, both clinically and epidemiologically, and therefore should be given appropriate attention in medical education. This report is based on a recent survey on the current state of radiation therapy teaching at university hospitals in Germany as well as the contents of the National Competence Based Learning Objectives Catalogue for Medicine 2.0 (Nationaler Kompetenzbasierter Lernzielkatalog Medizin 2.0, NKLM) and the closely related Subject Catalogue (Gegenstandskatalog, GK) of the Institute for Medical and Pharmaceutical Examination Questions (Institut für Medizinische und Pharmazeutische Prüfungsfragen, IMPP). The current recommendations of the German Society for Radiation Oncology (Deutsche Gesellschaft für Radioonkologie, DEGRO) regarding topics, scope and rationale for the establishment of radiation oncology teaching at the respective faculties are also included

Multi-messenger observations of a binary neutron star merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

Apophis Planetary Defense Campaign

We describe results of a planetary defense exercise conducted during the close approach to Earth by the near-Earth asteroid (99942) Apophis during 2020 December–2021 March. The planetary defense community has been conducting observational campaigns since 2017 to test the operational readiness of the global planetary defense capabilities. These community-led global exercises were carried out with the support of NASA’s Planetary Defense Coordination Office and the International Asteroid Warning Network. The Apophis campaign is the third in our series of planetary defense exercises. The goal of this campaign was to recover, track, and characterize Apophis as a potential impactor to exercise the planetary defense system including observations, hypothetical risk assessment and risk prediction, and hazard communication. Based on the campaign results, we present lessons learned about our ability to observe and model a potential impactor. Data products derived from astrometric observations were available for inclusion in our risk assessment model almost immediately, allowing real-time updates to the impact probability calculation and possible impact locations. An early NEOWISE diameter measurement provided a significant improvement in the uncertainty on the range of hypothetical impact outcomes. The availability of different characterization methods such as photometry, spectroscopy, and radar provided robustness to our ability to assess the potential impact risk. © 2022. The Author(s). Published by the American Astronomical Society.Brinson Foundation of ChicagoMoscow CenterNASA’s Planetary Defense Coordination Office, (80NSSC18K0284, 80NSSC18K1575, NN12AR55G)NEOOPlanetary Data SystemNational Aeronautics and Space Administration, NASA, (80NSSC18K0971)University of Maryland, UMDHorizon 2020 Framework Programme, H2020, (870403)Planetary Science Division, PSDNational Research Foundation, NRFMinistry of Education and Science of the Russian Federation, Minobrnauka, (075-15-2019-1623)National Research Foundation of Korea, NRFMinistry of Science and Higher Education of the Russian Federation, (80NSSC18K0849, FEUZ-2020-0030)Overall, the campaign successfully demonstrated the capability of the planetary defense community to respond in real time to a potentially impacting object and obtain data sufficient to characterize its orbit, brightness, size, spectrum, rotation period, and hazard to Earth. Timely reporting of astrometry and preliminary physical property analyses, with appropriate error bars, significantly improved our knowledge of the potential impact consequences. Human factors, such as the end-of-year holiday season, had a distinct impact on rapidly constraining the rotation period of Apophis and demonstrate the importance of building a broad coalition for planetary defense spanning continents and cultures. Future planetary defense campaigns should focus on targets with less-favorable apparitions that might better simulate a future discovery of a hazardous object. Acknowledgments The Apophis campaign was conducted as part of the International Asteroid Warning Network (IAWN). IAWN is supported by the Planetary Data System (PDS) Small Bodies Node (SBN) at the University of Maryland College Park. The work at the Jet Propulsion Laboratory, California Institute of Technology, was performed under a contract with the National Aeronautics and Space Administration (NASA). This material is based in part on work supported by NASA under the Science Mission Directorate Research and Analysis Programs. This publication makes use of data products from NEOWISE, which is a joint project of the University of Arizona and the Jet Propulsion Laboratory/California Institute of Technology, funded by the Planetary Science Division of NASA. Pan-STARRS is supported by the National Aeronautics and Space Administration under Grant No. 80NSSC18K0971 issued through the SSO Near Earth Object Observations Program. Part of this work was supported by the Russian Ministry of Science and Higher Education via the State Assignment Project FEUZ-2020-0030. Part of the observations performed with the Zeiss-1000 telescope of the Terskol Observatory Shared Research Centre of the Institute of Astronomy of the Russian Academy of Sciences. We are extremely grateful to the IRTF and GTC Observatories’ night and day staff for their overwhelming support and assistance that made the observations possible. D.P. & M.M. are thankful to Richard Binzel and Francesca DeMeo for sharing their experience and wisdom while planning and conducting the measurements. D.P. is grateful to the Israeli Space Agency. M.M. was supported by the National Aeronautics and Space Administration under grant No. 80NSSC18K0849 issued through the Planetary Astronomy Program. J.d.L., J.L., and M.P. acknowledge financial support from the NEOROCKS project, which has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No. 870403. This work was funded by NASA’s Planetary Defense Coordination Office. Supercomputing resources supporting this work were provided by the NASA High End Computing (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center. This work has made use of data from the Asteroid Terrestrial-impact Last Alert System (ATLAS) project. ATLAS is primarily funded to search for NEAs through NASA grants NN12AR55G, 80NSSC18K0284, and 80NSSC18K1575byproducts of the NEA search include images and catalogs from the survey area. The ATLAS science products have been made possible through the contributions of the University of Hawaii Institute for Astronomy, the Queen’s University Belfast, the Space Telescope Science Institute, and the South African Astronomical Observatory. This work is partially supported by the South African National Research Foundation (NRF). Spacewatch is supported by NASA/NEOO grants and the Brinson Foundation of Chicago, IL. We thank TUBITAK National Observatory for partial support in using the T100 telescope with project number 20CT100-1743. This work was supported by the Moscow Center of Fundamental and Applied Mathematics, Agreement with the Ministry of Science and Higher Education of the Russian Federation, No. 075-15-2019-1623. This work made extensive use of Python, specifically the NumPy (Harris et al. 2020), Astropy (Astropy Collaboration et al. 2013, 2018), Matplotlib (Hunter 2007), and SciPy (Virtanen et al. 2020b) packages