A new connection between the opening angle and the large-scale morphology of extragalactic radio sources

In the case of an initially conical jet, we study the relation between jet collimation by the external pressure and large-scale morphology. We first consider the important length-scales in the problem, and then carry out axisymmetric hydrodynamic simulations that include, for certain parameters, all these length-scales. We find three important scales related to the collimation region: (i) where the sideways ram-pressure equals the external pressure, (ii) where the jet density equals the ambient density, and (iii) where the forward ram-pressure falls below the ambient pressure. These scales are set by the external Mach-number and opening angle of the jet. We demonstrate that the relative magnitudes of these scales determine the collimation, Mach-number, density and morphology of the large scale jet. Based on analysis of the shock structure, we reproduce successfully the morphology of Fanaroff-Riley (FR) class I and II radio sources. Within the framework of the model, an FR I radio source must have a large intrinsic opening angle. Entrainment of ambient gas might also be important. We also show that all FR I sources with radio lobes or similar features must have had an earlier FR II phase.Comment: 14 pages, 10 figures, accepted by MNRAS, same as previous versio

Stratification for module categories of finite group schemes

The second author was partly supported by NSF grant DMS 1503044. The fourth author was partly supported by NSF grant DMS 0953011.Peer reviewedPostprin

Electronic health literacy in Swiss-German parents : cross-sectional study of eHealth literacy scale unidimensionality

Parents often use digital media to search for information related to their children's health. As the quantity and quality of digital sources meant specifically for parents expand, parents' digital health literacy is increasingly important to process the information they retrieve. One of the earliest developed and widely used instruments to assess digital health literacy is the self-reported eHealth Literacy Scale (eHEALS). However, the eHEALS has not been psychometrically validated in a sample of parents. Given the inconsistency of the eHEALS underlying factor structure across previous reports, it is particularly important for validation to occur

Measurements of the Cosmological Evolution of Magnetic Fields with the Square Kilometre Array

We investigate the potential of the Square Kilometre Array (SKA) for measuring the magnetic fields in clusters of galaxies via Faraday rotation of background polarised sources. [...] We find that about 10 per cent of the sky is covered by a significant extragalactic Faraday screen. Most of it has rotation measures between 10 and 100 rad/m/m. We argue that the cluster centres should have up to about 5000 rad/m/m. We show that the proposed mid frequency aperture array of the SKA as well as the lowest band of the SKA dish array are well suited to make measurements for most of these rotation measure values, typically requiring a signal-to-noise of ten. We calculate the spacing of sources forming a grid for the purpose of measuring foreground rotation measures: it reaches a spacing of 36 arcsec for a 100 hour SKA observation per field. We also calculate the statistics for background RM measurements in clusters of galaxies. We find that a first phase of the SKA would allow us to take stacking experiments out to high redshifts (>1), and provide improved magnetic field structure measurements for individual nearby clusters. The full SKA aperture array would be able to make very detailed magnetic field structure measurements of clusters with more than 100 background sources per cluster up to a redshift of 0.5 and more than 1000 background sources per cluster for nearby clusters, and could for reasonable assumptions about future measurements of electron densities in high redshift clusters constrain the power law index for the magnetic field evolution to better than dm=0.4, if the magnetic field in clusters should follow B ~ (1+z)^m.Comment: 12 pages, 10 figures, 3 tables, accepted by MNRAS, minor correction to eq (5

R³ - Research-, Response-, Result-oriented Teaching: Ein neues Unterrichtsformat zum nachhaltigen Wissenstransfer

Im Masterkurs „Sustainable Supply Chain Management“ wurde ein innovatives und vielschichtiges Seminar entwickelt. Es bietet Studierenden die besondere Herausforderung, Wissen durch eigene Forschung sowie in Teams und durch die Kooperation mit Partnern aus der Wirtschaft/der Industrie zu erlangen und dabei dieses Wissen mit kreativen Methoden zu systematisieren und weiter zu entwickeln, um am Ende eigene Ideen, Lösungen und Konzepte zu kreieren. Die Studierenden sind von Anfang an aktive Gestalter_innen der Unterrichtsinhalte, verfolgen das klare Lernziel, Resultate und Erkenntnisse aus der Forschung kreativ für Industriepartner aufzubereiten, und tragen dadurch zum Wissenstransfer bei

Therapie des Guillain Barré Syndroms: Unterschiede im Therapieansprechen unter Plasmapherese im Vergleich zur Immunglobulingabe

Retrospektive Untersuchung des Effektes einer sekundären Behandlung mittels Plasmaseparation gegenüber einer primären Therapie mit Immunglobulinen beim Guillain Barré Syndro

Toothache, tooth brushing frequency and dental check-ups in children and adolescents with and without disabilities

According to international studies, children and adolescents with disabilities have more tooth decay, brush their teeth less often twice a day and use preventive dental services less often than children and adolescents without disabilities. With data from the second follow-up to the German Health Interview and Examination Survey for Children and Adolescents (KiGGS Wave 2, 2014–2017), toothache, tooth brushing frequency and dental check-ups are examined in children and adolescents with and without disabilities. It was found that children and adolescents with disabilities had more toothache in the three months before the survey (23.5% and 15.9%, respectively) and brushed or got their teeth brushed twice a day less often (33.5% and 22.2%, respectively) than children and adolescents without disabilities. Differences in the utilisation of dental check-ups could not be determined. Overall, the results point to the importance of measures to promote tooth brushing frequency in order to improve the oral health of children and adolescents with disabilities. In addition, further opportunities should be created to collect data on the oral health of people with disabilities at the population level in health or participation studies

A Solution for Automated Grading of QDA Homework

Teaching research methods is important in any curriculum that prepares students for an academic career. While theoretical frameworks for qualitative theory building can be adequately conveyed through lecturing, the practices of qualitative data analysis (QDA) cannot. However, using experiential learning techniques for teaching QDA methods to large numbers of students presents a challenge to the instructor due to the effort required for the grading of homework. Any homework involving the coding of qualitative data will result in a myriad of different interpretations of the same data with varying quality. Grading such assignments requires significant effort. We approached this problem by using methods of inter-rater agreement and a model solution as a proxy for the quality of the submission. The automated agreement data serves as the foundation for a semi-automated grading process. Within this paper, we demonstrate that this proxy has a high correlation with the manual grading of submissions