Turbulent diffusion and drift in galactic magnetic fields and the explanation of the knee in the cosmic ray spectrum

We reconsider the scenario in which the knee in the cosmic ray spectrum is explained as due to a change in the escape mechanism of cosmic rays from the Galaxy from one dominated by transverse diffusion to one dominated by drifts. We solve the diffusion equations adopting realistic galactic field models and using diffusion coefficients appropriate for strong turbulence (with a Kolmogorov spectrum of fluctuations) and consistent with the assumed magnetic fields. We show that properly taking into account these effects leads to a natural explanation of the knee in the spectrum, and a transition towards a heavier composition above the knee is predicted.Comment: 17 pp., 6 figures; revised version with minor changes. To appear in JHE

Theory and Applications of Non-Relativistic and Relativistic Turbulent Reconnection

Realistic astrophysical environments are turbulent due to the extremely high Reynolds numbers. Therefore, the theories of reconnection intended for describing astrophysical reconnection should not ignore the effects of turbulence on magnetic reconnection. Turbulence is known to change the nature of many physical processes dramatically and in this review we claim that magnetic reconnection is not an exception. We stress that not only astrophysical turbulence is ubiquitous, but also magnetic reconnection itself induces turbulence. Thus turbulence must be accounted for in any realistic astrophysical reconnection setup. We argue that due to the similarities of MHD turbulence in relativistic and non-relativistic cases the theory of magnetic reconnection developed for the non-relativistic case can be extended to the relativistic case and we provide numerical simulations that support this conjecture. We also provide quantitative comparisons of the theoretical predictions and results of numerical experiments, including the situations when turbulent reconnection is self-driven, i.e. the turbulence in the system is generated by the reconnection process itself. We show how turbulent reconnection entails the violation of magnetic flux freezing, the conclusion that has really far reaching consequences for many realistically turbulent astrophysical environments. In addition, we consider observational testing of turbulent reconnection as well as numerous implications of the theory. The former includes the Sun and solar wind reconnection, while the latter include the process of reconnection diffusion induced by turbulent reconnection, the acceleration of energetic particles, bursts of turbulent reconnection related to black hole sources as well as gamma ray bursts. Finally, we explain why turbulent reconnection cannot be explained by turbulent resistivity or derived through the mean field approach.Comment: 66 pages, 24 figures, a chapter of the book "Magnetic Reconnection - Concepts and Applications", editors W. Gonzalez, E. N. Parke

Magnetic fields in cosmic particle acceleration sources

We review here some magnetic phenomena in astrophysical particle accelerators associated with collisionless shocks in supernova remnants, radio galaxies and clusters of galaxies. A specific feature is that the accelerated particles can play an important role in magnetic field evolution in the objects. We discuss a number of CR-driven, magnetic field amplification processes that are likely to operate when diffusive shock acceleration (DSA) becomes efficient and nonlinear. The turbulent magnetic fields produced by these processes determine the maximum energies of accelerated particles and result in specific features in the observed photon radiation of the sources. Equally important, magnetic field amplification by the CR currents and pressure anisotropies may affect the shocked gas temperatures and compression, both in the shock precursor and in the downstream flow, if the shock is an efficient CR accelerator. Strong fluctuations of the magnetic field on scales above the radiation formation length in the shock vicinity result in intermittent structures observable in synchrotron emission images. Resonant and non-resonant CR streaming instabilities in the shock precursor can generate mesoscale magnetic fields with scale-sizes comparable to supernova remnants and even superbubbles. This opens the possibility that magnetic fields in the earliest galaxies were produced by the first generation Population III supernova remnants and by clustered supernovae in star forming regions.Comment: 30 pages, Space Science Review

A qualitative exploration of patients' experiences of music therapy in an inpatient hospice in Singapore

International Journal of Palliative Nursing167344-35

CN56 Well-being and healthcare concerns of patients with advanced renal cell carcinoma: The RCC PROMs international survey

Background Renal cell carcinoma (RCC) is the most common type of kidney cancer, most frequently diagnosed in men over 60 and in higher-income settings. Around 30% of cases are of advanced RCC. Despite progress with targeted therapies and immunotherapy, patients with advanced RCC face difficulties with day-to-day living. Patient-reported outcomes provide crucial information to enhance clinicians’ understanding about what issues patients perceive to have the greatest impact on them and can help promote person-centred approaches to treatment and disease management. Methods As part of the larger EONS PROMs project (https://cancernurse.eu/research/proms_project/), an international online survey was launched in May 2022. With a sampling confidence level of 95% and a margin of error of 10%, we aimed to involve ≥89 patients with advanced RCC. The survey comprised a bespoke demographic/clinical form, the Functional Assessment of Cancer Therapy-Biologic Response Modifiers (FACT-BRM) questionnaire, and three questions on patients’ priority concerns. Results The survey included 105 patients. Typically, patients were men (n=62, 59%), on targeted therapy (n=31, 33.7%), middle-aged (median=44 years), and over 3 years since diagnosis (median=37 months). Descriptive analysis of individual FACT-BRM items revealed that patients: were bothered by too frequent an urge to urinate (70%), worried their condition will worsen (68%), worried about their partner or family (67%), felt helpless (60%), were unable to work (59%), and were concerned about end-of-life care (58%). Spontaneously, patients identified major concerns with wages, impact on family, and future response to treatment. Older age was a statistically significant predictor of higher FACT-BRM total scores (p<0.001), better physical wellbeing (p<0.001), and better emotional wellbeing (p<0.001). Receiving radiotherapy or targeted therapy were predictive of poorer physical wellbeing (p<0.05). Conclusions Identifying, monitoring, and responding to concerns relating to physical, emotional, social, and practical aspects of wellbeing can be meaningful steps towards provision of enhanced person-centred care in advanced RCC