The Effect of Porosity on X-ray Emission Line Profiles from Hot-Star Winds

We investigate the degree to which the nearly symmetric form of X-ray emission lines seen in Chandra spectra of early-type supergiant stars could be explained by a possibly porous nature of their spatially structured stellar winds. Such porosity could effectively reduce the bound-free absorption of X-rays emitted by embedded wind shocks, and thus allow a more similar transmission of red- vs. blue-shifted emission from the back vs. front hemispheres. For a medium consisting of clumps of size l and volume filling factor f, in which the `porosity length' h=l/f increases with local radius as h = h' r, we find that a substantial reduction in wind absorption requires a quite large porosity scale factor h' > 1, implying large porosity lengths h > r. The associated wind structure must thus have either a relatively large scale l~ r, or a small volume filling factor f ~ l/r << 1, or some combination of these. The relatively small-scale, moderate compressions generated by intrinsic instabilities in line-driving seem unlikely to give such large porosity lengths, leaving again the prospect of instead having to invoke a substantial (ca. factor 5) downward revision in assumed mass-loss rates.Comment: 6 pages in apj-emulate; 3 figures; submitted to Ap

Who was St David?

Where does St David's iconic status stem from and what is known of the man who lived 1500 years ago? Explore St David in more detail here..

Young Europeans ́ Forum 2019 “Building Bridges for Social Cohesion”

In many European societies, social cohesion is challenged by megatrends, such as globalization, digitalization, growing inequality, and migration. In addition – or in part as a consequence of those megatrends – our living together is confronted with increasing cultural diversity, a greater plurality of values and lifestyles, as well as a rise in populism, polarization and a loss of confidence in democracy. Recognizing that many European countries face these challenges, a number of important questions arise: What holds societies together? What must we do today so that this cohesiveness will remain present in the future? How can we foster social cohesion

On reciprocal equivalence of St\"ackel systems

In this paper we ivestigate St\"ackel transforms between different classes of parameter-dependent St\"ackel separable systems of the same dimension. We show that the set of all St\"ackel systems of the same dimension splits to equivalence classes so that all members within the same class can be connected by a single St\"ackel transform. We also give an explicit formula relating solutions of two St\"ackel-related systems. These results show in particular that any two geodesic St\"ackel systems are St\"ackel equivalent in the sense that it is possible to transform one into another by a single St\"ackel transform. We also simplify proofs of some known statements about multiparameter St\"ackel transform.Comment: We clarified arguments in Section 3, Studies in Applied Mathematics 201

Prise en charge domiciliaire d'une personne atteinte de démence de type d'Alzheimer: comment l'infirmière pourrait-elle accompagner le proche aidant dans l'acquisition et le développement de compétences : travail de Bachelor

Contexte : Aujourd’hui, les proches aidants sont en première ligne dans la prise en charge de personnes âgées atteintes de la maladie d’Alzheimer et vivant à domicile. Cette situation peut engendrer des difficultés pour les proches aidants (fardeau, problèmes de santé) qui vivent un changement de rôle tout au long de leur vie. La théorie des transitions d’Afaf Ibrahim Meleis peut être indiquée comme une philosophie de soin pour l’infirmière dans l’accompagnement d’un proche aidant vivant une transition. Question de recherche : Quelles seraient les interventions nfirmières possibles afin d’accompagner les proches aidants dans l’acquisition et le développement de compétences, en vue de diminuer l’impact de cette prise en charge

Psycho and The Orchestration of Anxiety

Since its release in 1960, Alfred Hitchcock’s Psycho has entered the consciousness of our culture as have few other films. Its striking imagery, combined with its universally recognised score, has prompted a wealth of scholarly output. New understanding in the areas of emotion and cognition now affords us the opportunity to re-examine this film from a less familiar vantage point. This article places Psycho within the context of American TV drama of the 1950s and explores the effect of Bernard Herrmann’s music on the emotional responses of the viewer, as well as the possible consequences of this effect upon the literal reading of the film

A Concise History of Western Music for Film-makers

The use of music in films has become almost ubiquitous in both drama and documentary. Music is used regularly in cinema, broadcasting and more recently, in interactive media. Yet audiences often criticise makers for its overuse, especially in actuality television. The problem is not merely concerned with the volume and placement of music, but of the internal nature and structure of the musical material itself. This article contextualises the history of western music in a way which may be able to help inform film makers and broadcasters about how music might be used more advantageously to accompany moving pictures