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We present results of full 3D hydrodynamical and radiative transfer simulations of the colliding stellar winds in the massive binary system η Carinae. We accomplish this by applying the SimpleX algorithm for 3D radiative transfer on an unstructured Voronoi-Delaunay grid to recent 3D smoothed particle hydrodynamics (SPH) simulations of the binary colliding winds. We use SimpleX to obtain detailed ionization fractions of hydrogen and helium, in 3D, at the resolution of the original SPH simulations. We investigate several computational domain sizes and Luminous Blue Variable primary star mass-loss rates. We furthermore present new methods of visualizing and interacting with output from complex 3D numerical simulations, including 3D interactive graphics and 3D printing. While we initially focus on η Car, the methods employed can be applied to numerous other colliding wind (WR 140, WR 137, WR 19) and dusty `pinwheel' (WR 104, WR 98a) binary systems. Coupled with 3D hydrodynamical simulations, SimpleX simulations have the potential to help determine the regions where various observed time-variable emission and absorption lines form in these unique objects.
We present 3D numerical simulations of the NGC6888 nebula considering the proper motion and the evolution of the star, from the red supergiant (RSG) to the Wolf-Rayet (WR) phase. Our simulations reproduce the limb-brightened morphology observed in [OIII] and X-ray emission maps. The synthetic maps computed by the numerical simulations show filamentary and clumpy structures produced by instabilities triggered in the interaction between the WR wind and the RSG shell.
The main objective of this work is to investigate the evolution of massive stars, and the interplay between them and the ionized gas for a sample of local metal-poor Wolf-Rayet galaxies.
Optical integral field spectrocopy was used in combination with multi-wavelength radio data.
Combining optical and radio data, we locate Wolf-Rayet stars and supernova remnants across the Wolf-Rayet galaxies to study the spatial correlation between them. This study will shed light on the massive star formation and its feedback, and will help us to better understand
distant star-forming galaxies.
We analyse whether a stellar atmosphere model computed with the code CMFGEN provides an optimal description of the stellar observations of WR 136 and simultaneously reproduces the nebular observations of NGC 6888, such as the ionization degree, which is modelled with the pyCloudy code. All the observational material available (far and near UV and optical spectra) were used to constrain such models. We found that the stellar temperature T∗, at τ = 20, can be in a range between 70 000 and 110 000 K, but when using the nebula as an additional restriction, we found that the stellar models with T∗ ∼ 70 000 K represent the best solution for both, the star and the nebula.
We suggest several ideas which when combined could lead to a new mechanism for long-term pulsations of very hot and luminous stars. These involve the interplay between convection, radiation, atmospheric clumping and winds, which collectively feed back to stellar expansion and contraction. We discuss these ideas and point out the future work required in order to fill in the blanks.
We present the first physical characterization of the young open cluster VVVCL041. We spectroscopically observed the cluster main-sequence stellar population and a very-massive star candidate: WR62-2. CMFGEN modelling to our near-infrared spectra indicates that WR62-2 is a very luminous (10^6.4±0.2 L⊙)and massive (∼ 80M⊙) star.
We present results from our near-infrared spectroscopy with VLT/ISAAC of four, massive eclipsing binary systems in the young, heavily reddened, massive Danks clusters. We derive accurate fundamental parameters and the distance to these massive systems, which comprise of OIf+, WR and O-type stars. Our goal is to increase the sample of well-studied WR stars and constrain their physics by comparison with evolutionary models.
Die Studieneingangsphase stellt für Studierende eine Schlüsselphase des tertiären Ausbildungsabschnitts dar. Fachwissenschaftliches Wissen wird praxisfern vermittelt und die Studierenden können die Zusammenhänge zwischen den Themenfeldern der verschiedenen Vorlesungen nicht erkennen. Zur Verbesserung der Situation wurde ein Workshop entwickelt, der die Verbindung der Programmierung und der Datenstrukturen vertieft. Dabei wird das Spiel Go-Moku1 als Android-App von den Studierenden selbständig entwickelt. Die Kombination aus Software (Java, Android-SDK) und Hardware (Tablet-Computer) für ein kleines realistisches Softwareprojekt stellt für die Studierenden eine neue Erfahrung dar.
Erstsemester-Studierende sind mit den Anforderungen des Lehr-/ Lernprozess einer Universität oder Fachhochschule noch nicht vertraut. Ihre Erwartungen orientieren sich vielmehr an ihrer bisherigen Lerngeschichte (Abitur, Fachabitur, o. ä.). Neben den fachlichen Anforderungen des ersten Semesters müssen die Studierenden also auch Veränderungen im Lehr-/Lernprozess erkennen und bewältigen. Es wird anhand einer Output-orientierten
informatischen Lehrveranstaltung aufgezeigt, dass sich aus deren strengen Anforderungen der Messbarkeit klare Kompetenzbeschreibungen ergeben, die besonders dem Orientierungsbedürfnis Erstsemester-Studierender entgegenkommen.
Lo pintoresco se puede definir como un sentimiento que invita al espectador de una escena particular a reproducirla en un cuadro, algo que permitió a los viajeros del siglo XIX transportar las imágenes como posesiones, especialmente a través de la publicación de un Atlas Pittoresque. Cada una de esas imágenes es un testimonio de los viajes y sus historias cruzadas. Este es el caso de la lámina III, Vista de la Plaza Mayor de México, que forma parte de la obra Vues des Cordillères et Monuments des Peuples Indigènes de l’Amérique, una imagen que ilustra las redes de intercambio que se sucedían entre artistas y científicos a través de los viajes y expediciones.
En este breve ensayo propongo que en la ascensión al Teide Alexander von Humboldt pudo adquirir una perspectiva integral, que le sirvió como marco de comunicación científica para aunar la multitud de datos que se había dispuesto a recoger en su breve estancia en la isla. Más aun, de ahí en adelante este marco además le serviría para darle sentido de conjunto a las incontables y diversas informaciones que recogería en los restantes cinco años de viaje. Para poner en evidencia el enfoque de la visita a Tenerife de Humboldt, analizo su relato de la ascensión al Teide suponiendo que está estructurado según los relatos de viajes épicos y peregrinaciones.
In this paper we describe the recent state of our research
project concerning computer science teachers’ knowledge on students’
cognition. We did a comprehensive analysis of textbooks, curricula
and other resources, which give teachers guidance to formulate assignments.
In comparison to other subjects there are only a few concepts
and strategies taught to prospective computer science teachers in university.
We summarize them and given an overview on our empirical
approach to measure this knowledge.
Es wird ein Informatik-Wettbewerb für Schülerinnen und Schüler der Sekundarstufe II beschrieben, der über mehrere Wochen möglichst realitätsnah die Arbeitswelt eines Informatikers vorstellt. Im Wettbewerb erarbeiten die Schülerteams eine Android-App und organisieren ihre Entwicklung durch Projektmanagementmethoden, die sich an professionellen, agilen Prozessen orientieren. Im Beitrag werden der theoretische Hintergrund zu Wettbewerben, die organisatorischen und didaktischen Entscheidung, eine erste Evaluation sowie Reflexion und Ausblick dargestellt.
BugHunt
(2015)
Competencies related to operating systems and computer
security are usually taught systematically. In this paper we present
a different approach, in which students have to remove virus-like
behaviour on their respective computers, which has been induced by
software developed for this purpose. They have to develop appropriate
problem-solving strategies and thereby explore essential elements of
the operating system. The approach was implemented exemplarily in
two computer science courses at a regional general upper secondary
school and showed great motivation and interest in the participating
students.
The paper presents two approaches to the development of
a Computer Science Competence Model for the needs of curriculum
development and evaluation in Higher Education. A normativetheoretical
approach is based on the AKT and ACM/IEEE curriculum
and will be used within the recommendations of the German
Informatics Society (GI) for the design of CS curricula. An empirically
oriented approach refines the categories of the first one with regard to
specific subject areas by conducting content analysis on CS curricula of
important universities from several countries. The refined model will be
used for the needs of students’ e-assessment and subsequent affirmative
action of the CS departments.
Computational Thinking
(2015)
Digital technology has radically changed the way people
work in industry, finance, services, media and commerce. Informatics
has contributed to the scientific and technological development of our
society in general and to the digital revolution in particular. Computational
thinking is the term indicating the key ideas of this discipline that
might be included in the key competencies underlying the curriculum
of compulsory education. The educational potential of informatics has
a history dating back to the sixties. In this article, we briefly revisit this
history looking for lessons learned. In particular, we focus on experiences
of teaching and learning programming. However, computational
thinking is more than coding. It is a way of thinking and practicing interactive
dynamic modeling with computers. We advocate that learners
can practice computational thinking in playful contexts where they can
develop personal projects, for example building videogames and/or robots,
share and discuss their construction with others. In our view, this
approach allows an integration of computational thinking in the K-12
curriculum across disciplines.
Concluding Remarks
(2015)
This paper originated from discussions about the need for
important changes in the curriculum for Computing including two focus
group meetings at IFIP conferences over the last two years. The
paper examines how recent developments in curriculum, together with
insights from curriculum thinking in other subject areas, especially mathematics
and science, can inform curriculum design for Computing.
The analysis presented in the paper provides insights into the complexity
of curriculum design as well as identifying important constraints and
considerations for the ongoing development of a vision and framework
for a Computing curriculum.