A Universal Law for Solar-Wind Turbulence at Electron Scales

The interplanetary magnetic fluctuation spectrum obeys a Kolmogorovian power law at scales above the proton inertial length and gyroradius which is well regarded as an inertial range. Below these scales a power law index around $-2.5$ is often measured and associated to nonlinear dispersive processes. Recent observations reveal a third region at scales below the electron inertial length. This region is characterized by a steeper spectrum that some refer to it as the dissipation range. We investigate this range of scales in the electron magnetohydrodynamic approximation and derive an exact and universal law for a third-order structure function. This law can predict a magnetic fluctuation spectrum with an index of $-11/3$ which is in agreement with the observed spectrum at the smallest scales. We conclude on the possible existence of a third turbulence regime in the solar wind instead of a dissipation range as recently postulated.Comment: 11 pages, will appear in Astrophys.

Towards an Ontological Modelling of Preference Relations

Preference relations are intensively studied in Economics, but they are also approached in AI, Knowledge Representation, and Conceptual Modelling, as they provide a key concept in a variety of domains of application. In this paper, we propose an ontological foundation of preference relations to formalise their essential aspects across domains. Firstly, we shall discuss what is the ontological status of the relata of a preference relation. Secondly, we investigate the place of preference relations within a rich taxonomy of relations (e.g. we ask whether they are internal or external, essential or contingent, descriptive or nondescriptive relations). Finally, we provide an ontological modelling of preference relation as a module of a foundational (or upper) ontology (viz. OntoUML). The aim of this paper is to provide a sharable foundational theory of preference relation that foster interoperability across the heterogeneous domains of application of preference relations

Electron and proton heating by solar wind turbulence

Previous formulations of heating and transport associated with strong magnetohydrodynamic (MHD) turbulence are generalized to incorporate separate internal energy equations for electrons and protons. Electron heat conduction is included. Energy is supplied by turbulent heating that affects both electrons and protons, and is exchanged between them via collisions. Comparison to available Ulysses data shows that a reasonable accounting for the data is provided when (i) the energy exchange timescale is very long and (ii) the deposition of heat due to turbulence is divided, with 60% going to proton heating and 40% into electron heating. Heat conduction, determined here by an empirical fit, plays a major role in describing the electron data

Spectropolarimetric Fluctuations in a Sunspot Chromosphere

The instrumental advances made in this new era of 4-meter class solar telescopes with unmatched spectropolarimetric accuracy and sensitivity, will enable the study of chromospheric magnetic fields and their dynamics with unprecedented detail. In this regard, spectropolarimetric diagnostics can provide invaluable insight into magneto-hydrodynamic (MHD) wave processes. MHD waves and, in particular, Alfv\'enic fluctuations associated to particular wave modes, were recently recognized as important mechanisms not only for the heating of the outer layers of the Sun's atmosphere and the acceleration of the solar wind, but also for the elemental abundance anomaly observed in the corona of the Sun and other Sun-like stars (also known as first ionisation potential; FIP) effect. Here, we take advantage of state-of-the-art and unique spectropolarimetric IBIS observations to investigate the relation between intensity and circular polarisation (CP) fluctuations in a sunspot chromosphere. Our results show a clear link between the intensity and CP fluctuations in a patch which corresponds to a narrow range of magnetic field inclinations. This suggests the presence of Alfv\'enic perturbations in the sunspot.Comment: 15 pages, 5 figures. Accepted for publication in Philosophical Transactions of the Royal Society

Using technology to deliver cancer follow-up : a systematic review

Peer reviewedPublisher PD

The Propagation of Coherent Waves Across Multiple Solar Magnetic Pores

Solar pores are efficient magnetic conduits for propagating magnetohydrodynamic wave energy into the outer regions of the solar atmosphere. Pore observations often contain isolated and/or unconnected structures, preventing the statistical examination of wave activity as a function of the atmospheric height. Here, using high-resolution observations acquired by the Dunn Solar Telescope, we examine photospheric and chromospheric wave signatures from a unique collection of magnetic pores originating from the same decaying sunspot. Wavelet analysis of high-cadence photospheric imaging reveals the ubiquitous presence of slow sausage-mode oscillations, coherent across all photospheric pores through comparisons of intensity and area fluctuations, producing statistically significant in-phase relationships. The universal nature of these waves allowed an investigation of whether the wave activity remained coherent as they propagate. Utilizing bisector Doppler velocity analysis of the Ca ii 8542 Å line, alongside comparisons of the modeled spectral response function, we find fine-scale 5 mHz power amplification as the waves propagate into the chromosphere. Phase angles approaching zero degrees between co-spatial line depths spanning different line depths indicate standing sausage modes following reflection against the transition region boundary. Fourier analysis of chromospheric velocities between neighboring pores reveals the annihilation of the wave coherency observed in the photosphere, with examination of the intensity and velocity signals from individual pores indicating they behave as fractured waveguides, rather than monolithic structures. Importantly, this work highlights that wave morphology with atmospheric height is highly complex, with vast differences observed at chromospheric layers, despite equivalent wave modes being introduced into similar pores in the photosphere

Solar Wind Turbulence and the Role of Ion Instabilities

International audienc

A Core Curriculum for Sociology in UK Undergraduate Medical Education

The valuable contribution of sociology to medicine has long been recognised in the UK and since 2009 the profession’s regulator, the General Medical Council (GMC), has reflected this in the learning outcomes required of all UK graduates in medicine. This recognition has created the need for support to those involved in student learning through programme design, development and delivery. This core curriculum for sociology in medical education provides a robust, evidence and practice-based means of linking sociological knowledge, content and topics to the GMC’s higher-level outcomes. The development of the core curriculum was an inclusive and collaborative process involving individuals responsible for teaching sociology in UK medical schools and a wide range of stakeholders including patient representatives, clinicians, students and medical educationalists. Our methodology was participative and orientated towards establishing consensus without sacrificing attention to diversity of views and experience. It coupled consultation with reviews of materials and research relevant to the teaching of sociology in medicine. The core curriculum comprises 6 topics. The first, entitled the sociological perspective, underpins those that follow. Taken together these topics represent a comprehensive, coherent and detailed guide to a curriculum fit for the purpose of enabling students to meet the GMC outcomes for graduates in medicine. For each topic, the document provides a guide to core learning outcomes and indicative content. The core curriculum recognises the diversity of approaches to pedagogy in medical education and also the contexts and structures within which teaching and learning take place. The curriculum identifies a range of learning and teaching opportunities such as patient involvement and the integration of sociological content into the clinical aspects of medical education. It also highlights challenges such as preserving modes and methods of assessment relevant to the demonstration of disciplinary knowledge required of students. The content of the curriculum is mapped to Tomorrow’s Doctors 2009/2015 and enables students to meet the outcomes relating to ‘scholar and scientist’ as laid down by the GMC