Search results for "Base"

TANAMI II. Additional sources

2018

TANAMI is a multiwavelength program monitoring active galactic nuclei (AGN) south of -30{deg} declination including high-resolution Very Long Baseline Interferometry (VLBI) imaging, radio, optical/UV, X-ray and {gamma}-ray studies. We have previously published first-epoch 8.4GHz VLBI images of the parsec-scale structure of the initial sample. In this paper, we present images of 39 additional sources. The full sample comprises most of the radio- and {gamma}-ray brightest AGN in the southern quarter of the sky, overlapping with the region from which high-energy (>100TeV) neutrino events have been found. We characterize the parsec-scale radio properties of the jets and compare with the quasi-s…

AB Dor A VLBI images

2020

The fast rotator, pre-main sequence star AB Dor A is a strong and persistent radio emitter. The extraordinary coronal flaring activity is thought to be the origin of compact radio emission and other associated phenomena, such as large slingshot prominences. We aim to investigate the radio emission mechanism and the milliarcsecond radio structure around AB Dor A. We performed phase-referenced VLBI observations at 22.3GHz, 8.4GHz, and 1.4GHz over more than one decade using the Australian VLBI array. Our 8.4GHz images show a double core-halo morphology, similar at all epochs, with emission extending at heights between 5 and 18 stellar radii. Furthermore, the sequence of the 8.4GHz maps shows a…

TANAMI monitoring of Centaurus A.

2015

Centaurus A (Cen A) is the closest radio-loud active galactic nucleus. Very Long Baseline Interferometry (VLBI) enables us to study the spectral and kinematic behavior of the radio jet-counterjet system on milliarcsecond scales, providing essential information for jet emission and propagation models. In the framework of the TANAMI monitoring, we investigate the kinematics and complex structure of Cen A on subparsec scales. We have been studying the evolution of the central parsec jet structure of Cen A for over 3.5-years. The proper motion analysis of individual jet components allows us to constrain jet formation and propagation and to test the proposed correlation of increased high-energy …

The gNLS1 galaxy PKS 2004-447. VLBI images

2016

Gamma-ray-detected radio-loud narrow-line Seyfert 1 (g-NLS1) galaxies constitute a small but interesting sample of the g-ray-loud AGN. The radio-loudest g-NLS1 known, PKS 2004-447, is located in the southern hemisphere and is monitored in the radio regime by the multiwavelength monitoring programme TANAMI. We aim for the first detailed study of the radio morphology and long-term radio spectral evolution of PKS 2004-447, which are essential for understanding the diversity of the radio properties of g-NLS1s. The TANAMI VLBI monitoring program uses the Australian Long Baseline Array (LBA) and telescopes in Antarctica, Chile, New Zealand, and South Africa to monitor the jets of radio-loud activ…

Catching the radio flare in CTA 102

2013

Very Long Baseline Interferometry (VLBI) observations can resolve the radio structure of active galactic nuclei (AGN) and provide estimates of the structural and kinematic characteristics on parsec-scales in their jets. The changes in the kinematics of the observed jet features can be used to study the physical conditions in the innermost regions of these sources. We performed multifrequency multiepoch Very Long Baseline Array (VLBA) observations of the blazar CTA102 during its 2006 radio flare, the strongest ever reported for this source. These observations provide an excellent opportunity to investigate the evolution of the physical properties of blazars, especially during these flaring e…

Heritability of anterior chamber depth and axial length: a population-based twin study among 66 to 79-year old female twins.

2014

DESIGNING AND IMPLEMENTING A BIG OPEN ONLINE COURSE BY USING A 3D VIRTUAL IMMERSIVE ENVIRONMENT – LESSONS LEARNED

2017

Open Education (OE) is a distance learning approach that was strategically chosen by the European Commission (EC) to encourage cost-effective training, upskilling and reskilling of large population groups and workforce with speed and flexibility. Institutions and businesses design and offer Open Online Courses (OOCs) to address skill gaps, organizational and societal needs. OOCs and especially Massive OOCs (MOOCs) are suffering from high rates of attrition, which is attributed to various factors such as learner isolation and lack of motivation to complete the course. Recommendations to address the retention gap in MOOCs include adopting a participation-driven approach, using game design tec…

Life-based design as an extension of problem-based learning:A tool for understanding people and technology

2015

Global conditions are changing at such a rate that foreseeing trends in technological development, economic fluctuations and climatic conditions is ever more difficult. When developing technologies, there is one constant factor that practitioners and researchers should be aware of, and that is people. This is not to say that people, culture and social conditions remain stagnant, for these too evolve with the surrounding circumstances. Rather, appropriate tools and capabilities for investigating people, their lives and life situations, are integral to understanding what people need in terms of technology, how these technologies will be used, and more importantly how they will be valued in th…

Hypervisor-Based White Listing of Executables

2019

We describe an efficient system for ensuring code integrity of an operating system (OS), both its own code and application code. The proposed system can protect from an attacker who has full control over the OS kernel. An evaluation of the system's performance suggests the induced overhead is negligible. peerReviewed

The connection between forms of guidance for inquiry-based learning and the communicative approaches applied : a case study in the context of pre-ser…

2019

Recent research has argued that inquiry-based science learning should be guided by providing the learners with support. The research on guidance for inquiry-based learning has concentrated on how providing guidance affects learning through inquiry. How guidance for inquiry-based learning could promote learning about inquiry (e.g. epistemic practices) is in need of exploration. A dialogic approach to classroom communication and pedagogical link-making offers possibilities for learners to acquire these practices. The focus of this paper is to analyse the role of different forms of guidance for inquiry-based learning on building the communicative approach applied in classrooms. The data for th…