Compact radio emission from z~0.2 X-ray bright AGN

Radio and X-ray emission of AGN appears to be correlated. The details of the underlying physical processes, however, are still not fully understood, i.e., to what extent is the X-ray and radio emission originating from the same relativistic particles or from the accretion-disk or corona or both. We study the cm radio emission of an SDSS/ROSAT/FIRST matched sample of 13 X-raying AGN in the redshift range 0.11< z < 0.37 at high angular resolution with the goal of searching for jet structures or diffuse, extended emission on sub-kpc scales. We use MERLIN at 18 cm for all objects and Western EVN at 18 cm for four objects to study the radio emission on scales of ~500 pc and ~40 pc for the MERLIN and EVN observations, respectively. The detected emission is dominated by compact nuclear radio structures. We find no kpc collimated jet structures. The EVN data indicate for compact nuclei on 40 pc scales, with brightness temperatures typical for accretion-disk scenarios. Comparison with FIRST shows that the 18 cm emission is resolved out up to 50% by MERLIN. Star-formation rates based on large aperture SDSS spectra are generally too small to produce considerable contamination of the nuclear radio emission. We can, therefore, assume the 18 cm flux densities to be produced in the nuclei of the AGN. Together with the ROSAT soft X-ray luminosities and black hole mass estimates from the literature, our sample objects follow closely the Merloni et al. (2003) fundamental plane relation, which appears to trace the accretion processes. Detailed X-ray spectral modeling from deeper hard X-ray observations and higher angular resolution at radio wavelengths are required to further proceed in the disentangling of jet and accretion related processes.Comment: 15 pages, 7 figures, submitted to A&

On critical scaling at the QCD N_f=2 chiral phase transition

We investigate the critical scaling of the quark propagator of N_f=2 QCD close to the chiral phase transition at finite temperature. We argue that it is mandatory to take into account the back-reaction effects of pions and the sigma onto the quark to observe critical behavior beyond mean field. On condition of self-consistency of the quark Dyson-Schwinger equation we extract the scaling behavior for the quark propagator analytically. Crucial in this respect is the correct pion dispersion relation when the critical temperature is approached from below. Our results are consistent with the known relations for the quark condensate and the pion decay constant from universality. We verify the analytical findings also numerically assuming the critical dispersion relation for the Goldstone bosons.Comment: 9 pages, 6 figure

Chiral and deconfinement phase transitions of two-flavour QCD at finite temperature and chemical potential

We present results for the chiral and deconfinement transition of two flavor QCD at finite temperature and chemical potential. To this end we study the quark condensate and its dual, the dressed Polyakov loop, with functional methods using a set of Dyson-Schwinger equations. The quark-propagator is determined self-consistently within a truncation scheme including temperature and in-medium effects of the gluon propagator. For the chiral transition we find a crossover turning into a first order transition at a critical endpoint at large quark chemical potential, $\mu_{EP}/T_{EP} \approx 3$. For the deconfinement transition we find a pseudo-critical temperature above the chiral transition in the crossover region but coinciding transition temperatures close to the critical endpoint.Comment: 4 pages, 4 figures. v2: minor changes, comments adde

Quark spectral properties above Tc from Dyson-Schwinger equations

We report on an analysis of the quark spectral representation at finite temperatures based on the quark propagator determined from its Dyson-Schwinger equation in Landau gauge. In Euclidean space we achieve nice agreement with recent results from quenched lattice QCD. We find different analytical properties of the quark propagator below and above the deconfinement transition. Using a variety of ansaetze for the spectral function we then analyze the possible quasiparticle spectrum, in particular its quark mass and momentum dependence in the high temperature phase. This analysis is completed by an application of the Maximum Entropy Method, in principle allowing for any positive semi-definite spectral function. Our results motivate a more direct determination of the spectral function in the framework of Dyson-Schwinger equations

Supporting remote therapeutic interventions with voice assistant technology

Nowadays, digital personal assistants are incorporated in many devices. Smart TVs, smartphones and stand-alone voice assistants like Amazon Alexa allow owners to control their smart home systems, play music on command or lookup information on the internet via voice queries. Using custom skills from various third-party vendors, almost any company can have a skill supporting the needs of their customers or control their devices. Furthermore, therapeutic interventions represent a vital part of most therapies, but there are some underlying struggles during therapies for which therapists can utilize the support of smart mobile devices. As an extension of an already existing system called Albatros, its features have been converted into an custom Alexa skill called remote interventions. But voice assistants can do more than improving everyday life, like helping people during medical therapies. A vital part of such therapies are therapeutic interventions, but therapists often face struggles when monitoring a patients progress and results. To overcome this problem, an existing system called Albatros allows a therapist to review the patients status. As an extension to the existing Albatros system, its features have been incorporated into a custom Alexa skill called remote interventions. Aiming to contribute to the proof of concept, the objective of this thesis is to demonstrate the development process of a custom Alexa skill which implements the features of retrieving exercises, allowing patients to record feedback via a smart speaker which can then be accessed by the therapist. With the addition of a notification feature the system also supports patients in remembering how and when to do their exercises properly. Due to the proof of concept nature of the project, apart from the actual development process, an analysis of whether or not the ideas and features translate well into a voice driven platform is performed