Solar Orbiter's encounter with the tail of comet C/2019 Y4 (ATLAS): Magnetic field draping and cometary pick-up ion waves

ontext. Solar Orbiter is expected to have flown close to the tail of comet C/2019 Y4 (ATLAS) during the spacecraft’s first perihelion in June 2020. Models predict a possible crossing of the comet tails by the spacecraft at a distance from the Sun of approximately 0.5 AU. Aims. This study is aimed at identifying possible signatures of the interaction of the solar wind plasma with material released by comet ATLAS, including the detection of draped magnetic field as well as the presence of cometary pick-up ions and of ion-scale waves excited by associated instabilities. This encounter provides us with the first opportunity of addressing such dynamics in the inner Heliosphere and improving our understanding of the plasma interaction between comets and the solar wind. Methods. We analysed data from all in situ instruments on board Solar Orbiter and compared their independent measurements in order to identify and characterize the nature of structures and waves observed in the plasma when the encounter was predicted. Results. We identified a magnetic field structure observed at the start of 4 June, associated with a full magnetic reversal, a local deceleration of the flow and large plasma density, and enhanced dust and energetic ions events. The cross-comparison of all these observations support a possible cometary origin for this structure and suggests the presence of magnetic field draping around some low-field and high-density object. Inside and around this large scale structure, several ion-scale wave-forms are detected that are consistent with small-scale waves and structures generated by cometary pick-up ion instabilities. Conclusions. Solar Orbiter measurements are consistent with the crossing through a magnetic and plasma structure of cometary origin embedded in the ambient solar wind. We suggest that this corresponds to the magnetotail of one of the fragments of comet ATLAS or to a portion of the tail that was previously disconnected and advected past the spacecraft by the solar wind

The Legal Landscape of Concussion

ContextConcussion legislation has been enacted in all 50 of the United States, aiming to prevent mild traumatic brain injuries and the potential long-term sequelae of these injuries in youth athletics. Sports medicine providers, in addressing this major public health concern, are tasked with adhering to the established standards of medical care while also considering the legal implications.Evidence acquisitionThe PubMed (2011-2016) database was searched using the following search terms: concussion, sports concussion, legislation, and concussion legislation. References from consensus statements, review articles, and book chapters were also utilized.Study designClinical review.Level of evidenceLevel 4.ResultsThe Lystedt law and its progeny have increased awareness of the signs and symptoms of sports concussion, but adherence to state legislation can pose some challenges.ConclusionThe presence of concussion legislation places a responsibility on the sports medicine provider to have a firm understanding of the legality of concussion management in the state(s) in which they practice

Return-to-work challenges following a work-related mild TBI: The injured worker perspective

Primary objective: To explore how individuals with work-related mild traumatic brain injury (wrMTBI) experience return-to-work (RTW) processes when returning to the workplace where the injury occurred.Design: RTW experiences were explored using in-depth interviews and an inductive analytic approach. Qualitative analysis guided by the research question moved through phases of line-by-line and thematic coding through which categories and the interaction between categories emerged.Participants: Twelve workers diagnosed with a wrMTBI reported on their RTW experiences following wrMTBIs that occurred 3-5 years prior to the time of the interview.Main outcomes and results: Participants perceived employer and workers compensation factors as profoundly influencing their RTW experiences. Participants consistently reported that employers and workers compensation representatives had an inadequate understanding of wrMTBI sequelae. Six of 12 participants were re-injured following their wrMTBI, with three of these injuries occurring at work.Conclusion: Employers, co-workers and workers compensation representatives should be aware of wrMTBI sequelae so injured workers can receive appropriate supports and both stigmatization and re-injury can be mitigated. Greater attention to the structural and social elements of workplace and compensation environments could inform strategies to break down barriers to successful return-to-work following a wrMTBI.</p