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Current curricular trends require teachers in Baden-
Wuerttemberg (Germany) to integrate Computer Science (CS) into
traditional subjects, such as Physical Science. However, concrete guidelines
are missing. To fill this gap, we outline an approach where a
microcontroller is used to perform and evaluate measurements in the
Physical Science classroom.
Using the open-source Arduino platform, we expect students to acquire
and develop both CS and Physical Science competencies by using a
self-programmed microcontroller. In addition to this combined development
of competencies in Physical Science and CS, the subject matter
will be embedded in suitable contexts and learning environments,
such as weather and climate.
We compute spectral libraries for populations of coeval stars using state-of-the-art massive-star evolutionary tracks that account for different astrophysics including rotation and close-binarity. Our synthetic spectra account for stellar and nebular contributions. We use our models to obtain E(B – V ), age, and mass for six clusters in spiral galaxy NGC 1566, which have ages of < 50 Myr and masses of > 5 x 104M⊙ according to standard models. NGC 1566 was observed from the NUV to the I-band as part of the imaging Treasury HST program LEGUS: Legacy Extragalactic UV Survey. We aim to establish i) if the models provide reasonable fits to the data, ii) how well the models and photometry are able to constrain the cluster properties, and iii) how different the properties obtained with different models are.
Observations of the WC9+OB system WR65 in the infrared show variations of its dust emission consistent with a period near 4.8 yr, suggesting formation in a colliding-wind binary (CWB) having an elliptical orbit. If we adopt the IR maximum as zero phase, the times of X-ray maximum count and minimum extinction to the hard component measured by Oskinova & Hamann fall at phases 0.4–0.5, when the separation of the WC9 and OB stars is greatest. We consider WR65 in the context of other WC8–9+OB stars showing dust emission.
Die Arbeitswelt im Fokus
(2015)
Für Bachelor-Studierende der Wirtschaftsinformatik im zweiten Semester an der Fachhochschule Kiel werden im Modul Informationsmanagement neben klassischen didaktischen Ansätzen in einer seminaristischen Unterrichtsform so genannte „Aktivbausteine“ eingesetzt: Studierende erhalten zum einen die Gelegenheit, sich im Kontakt mit Fach- und Führungskräften aus der Industrie ein konkretes Bild vom Beruf der Wirtschaftsinformatikerin bzw. des Wirtschaftsinformatikers zu machen; zum anderen erarbeiten sie innovative Ansätze der Prozessverbesserung aus Sicht der IT oder mit Nutzenpotenzial für die IT und präsentieren ihre Ergebnisse öffentlich im Rahmen des Kieler Prozessmanagementforums. Diese Aktivbausteine dienen insbesondere der Berufsfeldorientierung: Durch die Informationen, die die Studierenden über die Anforderungen und Tätigkeiten von im Beruf stehenden Menschen erhalten, werden sie in die Lage versetzt, fundierte Entscheidungen bzgl. ihrer Studiengestaltung und Berufswahl zu treffen. Im Beitrag wird die Konzeption der Bausteine vorgestellt und deren Grad der Zielerreichung durch aktuelle Evaluationsergebnisse erläutert. Zudem wird die motivationale Wirkung der Aktivbausteine anhand der Theorie der Selbstbestimmung von Deci und Ryan [DR1985, DR1993, DR2004] erläutert.
Der Erwerb der südamerikanischen Reisetagebücher Alexander von Humboldts durch die Staatsbibliothek Preußischer Kulturbesitz war 2014 ein bedeutendes Ereignis. In einem ersten Schritt wertet der Artikel unveröffentlichte Teile der Tagebücher und Dokumente aus dem Nachlass aus, um den „Kosmos Humboldt´scher Interessen“ zum Thema Pflanzengeographie zu umreißen, darunter auch seine Überlegungen zum Einfluss von Mensch und Tier auf die Ausbreitung von Pflanzen und die Veränderung von Vegetation. Die Einsichten des Gelehrten zur Abhängigkeit Europas von der sogenannten „Neuen Welt“ hinsichtlich der Nahrungsmittel werden ebenso behandelt. So vertrat Humboldt in seinen Ausführungen zum Thema „Was sind Barbaren?“ die These, dass Isolierung von Menschen aus der Gemeinschaft, Elend, Nahrungsmangel, klimatische Ursachen usw. „die Spuren von Zivilisation vertilgen“. Er betonte, dass es nötig sein, in einem weltweiten Wettstreit intellektueller Kräfte die Ressourcenknappheit zu überwinden.
Luminous Blue Variables (LBVs) are stars is a transitional phase massive stars may enter while evolving from main-sequence to Wolf-Rayet stars. The to LBVs intrinsic photometric variability is based on the modulation of the stellar spectrum. Within a few years the spectrum shifts from OB to AF type and back. During their cool phase LBVs are close to the Humphreys-Davidson (equivalent to Eddington/Omega-Gamma) limit. LBVs have a rather high mass loss rate, with stellar winds that are fast in the hot and slower in the cool phase of an LBV. These alternating wind velocities lead to the formation of LBV nebulae by wind-wind interactions. A nebula can also be formed in a spontaneous giant eruption in which larger amounts of mass are ejected. LBV nebulae are generally small (< 5 pc) mainly gaseous circumstellar nebulae, with a rather large fraction of LBV nebulae being bipolar. After the LBV phase the star will turn into a Wolf-Rayet star, but note that not all WR stars need to have passed the LBV phase. Some follow from the RSG and the most massive directly from the MS phase. In general WRs have a large mass loss and really fast stellar winds. The WR wind may interact with winds of earlier phases (MS, RSG) to form WR nebulae. As for WR with LBV progenitors the scenario might be different, here no older wind is present but an LBV nebula! The nature of WR nebulae are therefore manifold and in particular the connection (or family ties) of WR to LBV nebulae is important to understand the transition between these two phases, the evolution of massive stars, their winds, wind-wind and wind-nebula interactions. Looking at the similarities and differences of LBV and WR nebula, figuring what is a genuine LBV and WR nebula are the basic question addressed in the analysis presented here.
How Things Work
(2015)
Recognizing and defining functionality is a key competence
adopted in all kinds of programming projects. This study investigates
how far students without specific informatics training are able to identify
and verbalize functions and parameters. It presents observations
from classroom activities on functional modeling in high school chemistry
lessons with altogether 154 students. Finally it discusses the potential
of functional modelling to improve the comprehension of scientific
content.
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.
The interaction between massive star formation and gas is a key ingredient in galaxy evolution. Given the level of observational detail currently achievable in nearby starbursts, they constitute ideal laboratories to study interaction process that contribute to global evolution in all types of galaxies. Wolf-Rayet (WR) stars, as an observational marker of high mass star formation, play a pivotal role and their winds can strongly influence the surrounding gas. Imaging spectroscopy of two nearby (<4 Mpc) starbursts, both of which show multiple regions with WR stars, are discussed. The relation between the WR content and the physical and chemical properties of the surrounding ionized gas is explored.
Ziel einer neuen Studieneingangsphase ist, den Studierenden bis zum Ende des ersten Semesters ein vielfältiges Berufsbild der Informatik und Wirtschaftsinformatik mit dem breiten Aufgabenspektrum aufzublättern und damit die Zusammenhänge zwischen den einzelnen Modulen des Curriculums zu verdeutlichen. Die Studierenden sollen in die Lage versetzt werden, sehr eigenständig die Planung und Gestaltung ihres Studiums in die Hand zu nehmen.
The Wolf-Rayet (WR) phenomenon is widespread in astronomy. It involves classical WRs, very massive stars (VMS), WR central stars of planetary nebula CSPN [WRs], and supernovae (SNe). But what is the root cause for a certain type of object to turn into an emission-line star? In this contribution, I discuss the basic aspects of radiation-driven winds that might reveal the ultimate difference between WR stars and canonical O-type stars. I discuss the aspects of (i) self-enrichment via CNO elements, (ii) high effective temperatures (Tₑff), (iii) an increase in the helium abundance (Y ), and finally (iv) the Eddington factor Γₑ. Over the last couple of years, we have made a breakthrough in our understanding of Γₑ -dependent mass loss, which will have far-reaching consequences for the evolution and fate of the most massive stars in the Universe. Finally, I discuss the prospects for studies of the WR phenomenon in the highest redshift Lyα and He ii emitting galaxies.
We first give a short historical overview with some key facts of massive star population synthesis with binaries. We then discuss binary population codes and focus on two ingredients which are important for massive star population synthesis and which may be different in different codes. Population simulations with binaries is the third part where we consider the initial massive binary frequency, the RSG/WR and WC/WN and SNII/SNIbc number ratio's, the probable initial rotational velocity distribution of massive stars.
In this contribution, we provide a detailed dynamical analysis of the interfacial hydrogen migration mediated by scanning tunneling microscopy (STM). Contributions from the STM-current and from the non-adiabatic couplings are taken into account using only first principle models. The slight asymmetry of the tunnelling rates with respect to the potential bias sign inferred from experimental observations is reproduced by weighting the contributions of the metal acceptor–donor states for the propagation of the impinging electrons. The quasi-thermal inelastic collision mechanism is treated perturbatively. The influence of hydrogen pre-coverage is also investigated using new potential energy surfaces obtained from periodic density functional theory calculations. Fully quantum dynamical simulations of the system evolution are performed by solving the Pauli master equation, providing insight into the reaction mechanism of STM manipulation of subsurface hydrogens. It is observed that the hydrogen impurity favors resurfacing over occupation of the bulk and subsurface sites whenever possible. The present simulations give strong indication that the experimentally observed protuberances after STM-excitation are due to hydrogen accumulating in the vicinity of the surface.
The enigmatic oxygen-sequence Wolf-Rayet stars represent a rare stage in the evolution of massive stars. Their properties can provide unique constraints on the pre-supernova evolution of massive stars. This work presents the results of a quantitative spectroscopic analysis of the known single WO stars, with the aim to obtain the key stellar parameters and deduce their evolutionary state.X-Shooter spectra of the WO stars are modeled using the line-blanketed non-local thermal equilibrium atmosphere code cmfgen. The obtained stellar parameters show that the WO stars are very hot, with temperatures ranging from 150 kK to 210 kK. Their chemical composition is dominated by carbon (>50%), while the helium mass fraction is very low (down to 14%). Oxygen mass fractions reach as high as 25%. These properties can be reproduced with dedicated evolutionary models for helium stars, which show that the stars are post core-helium burning and very close to their eventual supernova explosion. The helium-star masses indicate initial masses or approximately 40 - 60M⊙.Thus, WO stars represent the final evolutionary stage of stars with estimated initial masses of 40 - 60M⊙. They are post core-helium burning and may explode as type Ic supernovae within a few thousand years.
We discuss our most recent findings on the diffuse X-ray emission within Wolf-Rayet (WR) nebulae. The best-quality X-ray observations of these objects are those performed by XMM- Newton and Chandra towards S 308, NGC 2359, and NGC 6888. Even though these three WR nebulae might have different formation scenarios, they all share similar characteristics: i) the main plasma temperatures of the X-ray-emitting gas is found to be T =[1–2]×^K, ii) the diffuse X-ray emission is confined inside the [O iii] shell, and iii) their X-ray luminosities and electron densities in the 0.3–2.0 keV energy range are LX ≈10^33–10^34 erg s-1 and ne ≈0.1–1 cm^-3 . These properties and the nebular-like abundances of the hot gas suggest mixing and/or thermal conduction is taking an important rôle reducing the temperature of the hot bubble.
The evolution of massive stars is strongly influenced by their initial chemical composition. We have computed rapidly-rotating massive star models with low metallicity (∼1/50 Z⊙) that evolve chemically homogeneously and have optically-thin winds during the main sequence evolution. These luminous and hot stars are predicted to emit intense mid- and far-UV radiation, but without the broad emission lines that characterize WR stars with optically-thick winds. We show that such Transparent Wind UV-Intense (TWUIN) stars may be responsible for the high number of He ii ionizing photons observed in metal-poor dwarf galaxies, such as IZw 18. We find that these TWUIN stars are possible long-duration gamma-ray burst progenitors.
Think logarithmically!
(2015)
We discuss here a number of algorithmic topics which we
use in our teaching and in learning of mathematics and informatics to
illustrate and document the power of logarithm in designing very efficient
algorithms and computations – logarithmic thinking is one of the
most important key competencies for solving real world practical problems.
We demonstrate also how to introduce logarithm independently
of mathematical formalism using a conceptual model for reducing a
problem size by at least half. It is quite surprising that the idea, which
leads to logarithm, is present in Euclid’s algorithm described almost
2000 years before John Napier invented logarithm.
The X-ray observations of the colliding wind binary WR 21a is reported. The first monitoring performed by Swift/XRT in order to reveal the phase-locked variation. Our observations cover 201 different epochs from 2013 October 1 to 2015 January 30 for a total exposure of about 306 ks. It is found for the first time that the luminosity varies roughly in inverse proportion to the separation of the two stars before the X-ray maximum but later drops rapidly toward periastron.
In this paper, I review observational evidence from spectroscopy and polarimetry for the presence of small and large scale structure in the winds of Wolf-Rayet (WR) stars. Clumping is known to be ubiquitous in the winds of these stars and many of its characteristics can be deduced from spectroscopic time-series and polarisation lightcurves. Conversely, a much smaller fraction of WR stars have been shown to harbour larger scale structures in their wind (∼ 1/5) while they are thought to be present is the winds of most of their O-star ancestors. The reason for this difference is still unknown.
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.
The feedback from massive stars is important to super star cluster (SSC) evolution and the timescales on which it occurs. SSCs form embedded in thick material, and eventually, the cluster is cleared out and revealed at optical wavelengths – however, this transition is not well understood. We are investigating this critical SSC evolutionary transition with a multi-wavelength observational campaign. Although previously thought to appear after the cluster has fully removed embedding natal material, we have found that SSCs may host large populations of Wolf-Rayet stars. These evolved stars provide ionization and mechanical feedback that we hypothesize is the tipping point in the combined feedback processes that drive a SSC to emerge. Utilizing optical spectra obtained with the 4m Mayall Telescope at Kitt Peak National Observatory and the 6.5m MMT, we have compiled a sample of embedded SSCs that are likely undergoing this short-lived evolutionary phase and in which we confirm the presence of Wolf-Rayet stars. Early results suggest that WRs may accelerate the cluster emergence.
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.
For the calculation of the work in an irreversible pressure-volume change, we propose approxima-tions, which in contrast to the usual representation in the literature reflect the work performed during expansion and compression symmetrically. The calculations are based on the Reversible-Share-Theorem: Is used the force to overcome for calculating the work, so it captures only the configurational reversible work share.
Die Wahl des richtigen Studienfaches und die daran anschließende
Studieneingangsphase sind oft entscheidend für den erfolgreichen Verlauf eines Studiums. Eine große Herausforderung besteht dabei darin, bereits in den ersten Wochen des Studiums bestehende Defizite in vermeintlich einfachen Schlüsselkompetenzen zu erkennen und diese so bald wie möglich zu beheben. Eine zweite, nicht minder wichtige Herausforderung ist es, möglichst frühzeitig für jeden einzelnen Studierenden zu erkennen, ob er bzw. sie das individuell richtige Studienfach gewählt hat, das den jeweiligen persönlichen Neigungen, Interessen und Fähigkeiten entspricht und zur Verwirklichung der eigenen Lebensziele beiträgt. Denn nur dann sind Studierende ausreichend stark und dauerhaft intrinsisch motiviert, um ein anspruchsvolles, komplexes Studium erfolgreich durchzuziehen. In diesem Beitrag fokussieren wir eine Maßnahme, die die Studierenden an einen Prozess zur systematischen Reflexion des eigenen Lernprozesses und der eigenen Ziele heranführt und beides in Relation setzt.
The poster and abstract describe the importance of teaching
information security in school. After a short description of information
security and important aspects, I will show, how information security
fits into different guidelines or models for computer science educations
and that it is therefore on of the key competencies. Afterwards I will
present you a rough insight of teaching information security in Austria.
Massive, luminous stars reaching the Eddington limit in their interiors develop very dilute, extended envelopes. This effect is called envelope inflation. If the progenitors of Type Ib/c supernovae, which are believed to be Wolf-Rayet (WR) stars, have inflated envelopes then the shock breakout signals diffuse in them and can extend their rise times significantly. We show that our inflated, hydrogen-free, WR stellar models with a radius of ∼R⊙ can have shock breakout signals longer than ∼ 60 s. The puzzlingly long shock breakout signal observed in the Type Ib SN 2008D can be explained by an inflated progenitor envelope, and more such events might argue in favour of existence of inflated envelopes in general.
This article shows a discussion about the key competencies
in informatics and ICT viewed from a philosophical foundation presented
by Martha Nussbaum, which is known as ‘ten central capabilities’.
Firstly, the outline of ‘The Capability Approach’, which has been presented
by Amartya Sen and Nussbaum as a theoretical framework of
assessing the state of social welfare, will be explained. Secondly, the
body of Nussbaum’s ten central capabilities and the reason for being
applied as the basis of discussion will be shown. Thirdly, the relationship
between the concept of ‘capability’ and ‘competency’ is to be
discussed. After that, the author’s assumption of the key competencies
in informatics and ICT led from the examination of Nussbaum’s ten
capabilities will be presented.
Colliding Wolf-Rayet (WR) winds produce thermal X-ray emission widely observed by X-ray telescopes. In wide WR+O binaries, such as WR 140, the X-ray flux is tied to the orbital phase, and is a direct probe of the winds’ properties. In the Galactic center, ~30 WRs orbit the super massive black hole (SMBH) within ~10”, leading to a smorgasbord of wind-wind collisions. To model the X-ray emission of WR 140 and the Galactic center, we perform 3D hydrodynamic simulations to trace the complex gaseous flows, and then carry out 3D radiative transfer calculations to compute the variable X-ray spectra. The model WR 140 RXTE light curve matches the data well for all phases except the X-ray minimum associated with periastron, while the model spectra agree with the RXTE hardness ratio and the shape of the Suzaku observations throughout the orbit. The Galactic center model of the Chandra flux and spectral shape match well in the region r ≤ 3”, but the model flux falls off too rapidly beyond this radius.
The Westerlund 1 (Wd1) cluster hosts a rich and varied collection of massive stars. Its dynamical youth and the absence of ongoing star formation indicate a coeval population. As such, the simultaneous presence of both late-type supergiants and Wolf-Rayet stars has defied explanation in the context of single-star evolution. Observational evidence points to a high binary fraction, hence this stellar population offers a robust test for stellar models accounting for both single-star and binary evolution. We present an optical to near-IR (VLT & NTT) spectroscopic analysis of 22 WR stars in Wd 1, delivering physical properties for the WR stars.
We discuss how these differ from the Galactic field population, and how they may be reconciled with the predictions of single and binary evolutionary models.
When Jesus Spoke Yiddish
(2015)
In this paper, I wish to bring some evidences from a Yiddish manuscript of the “Toledot Yeshu” which has not yet been the object of research: MS. Günzburg, 1730 kept in the Russian State Library in Moscow and dated 17th century. The manuscript is part of the so-called ‘Herode-tradition’ of the “Toledot Yeshu”. This means that the Yiddish manuscript is connected to the version printed in Hebrew and accompanied by a Latin translation by the Swiss pastor and theologian Johann Jacob Uldrich (Huldricus, 1683–1731) in Leiden in 1705, bearing the title “Historia Jeschuae Nazareni”. Given the uncertainty about the exact dating of the Yiddish manuscript, a comparison between the Hebrew and the Yiddish can still allow some remarks concerning the characteristics of the Yiddish version and posit some questions about the transmission and the reception of this challenging and intriguing text.
In this contribution we present some preliminary results obtained from a SOAR-Goodman optical spectroscopic survey aimed to confirm the OIf* - OIf*/WN nature of a sample of Galactic candidates that were previously confirmed as massive stars based on near-infrared spectra taken with OSIRIS at SOAR. With only a few of such stars known in the Galaxy to date, our study significantly contributes to improve the number of known Galactic O2If* stars, as well as almost doubling the number of known members of the galactic sample of the rare type OIf*/WN.
Peer Assessment ist eine Methode, bei der die Teilnehmer eine gestellte Aufgabe nicht nur bearbeiten und einreichen, sondern – in einer zweiten Phase – diese auch gegenseitig überprüfen, kommentieren und bewerten. Durch diese Methode wird, auch in sehr großen Veranstaltungen, das Üben mit individuellen Bewertungen und individuellem Feedback möglich.
Im Wintersemester 2013/14 wurde dieser Ansatz in der Erstsemesterveranstaltung Programmieren an der Technischen Hochschule Nürnberg mit 340 Studierenden als semesterbegleitendes Online-Pflichtpraktikum erprobt. Bei gleichen Leistungsanforderungen wurde bei Studierenden, die erfolgreich am Praktikum teilnahmen, eine Reduzierung der Durchfallquote um durchschnittlich 60 % und eine Verbesserung der Durchschnittsnote um 0,6 – 0,9 Notenstufen erzielt. Zudem lernten die teilnehmenden Studierenden kontinuierlicher, bereiteten Lerninhalte besser nach und gelangten zu einer überwiegend positiven Einschätzung des Praktikums und der Methode. Im E-Learning System Moodle kann Peer Assessment, mit moderatem Umsetzungs- und Betreuungsaufwand, mit der Workshop-Aktivität realisiert werden. Im Beitrag wird auf die Schlüsselelemente des erfolgreichen Einsatzes von Peer Assessment eingegangen.
We an optically-thick, transonic, steady wind model for a H-free Wolf-Rayet star. A bifurcation is found across a critical mass loss rate Mb. Slower winds M < Mb extend by several hydrostatic stellar radii, reproduce features of envelope in ation from Petrovic et al. (2006) and Gräfener et al. (2012), and are energetically unbound. This work is of particular interest for extended envelopes and winds, radiative hydrodynamic instabilities (eg. wind stagnation, clumping, etc.), and NLTE atmospheric models.
I. Einführung
II. Die Kreaturwürde im schweizerischen
Recht – Entstehung und Konzeption
III. Inhalt und Bedeutung der Kreaturwürde
IV. Die besondere Herausforderung:
Würde der Pflanze
V. Kreaturwürde und Menschenwürde
VI. Kreaturwürde in der Gentechnologie
VII. Kreaturwürde im Tierschutz
VIII. Reflexion
A project involving the composition of a number of pieces
of music by public participants revealed levels of engagement with and
mastery of complex music technologies by a number of secondary student
volunteers. This paper reports briefly on some initial findings of
that project and seeks to illuminate an understanding of computational
thinking across the curriculum.
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 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.
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.
In 1945, Zinovii Shenderovich Tolkatchev (1903–1977), a Soviet artist of Jewish origin, created a striking series of five images entitled “Jesus in Majdanek”. The series was the culmination of Tolkatchev‘s intensive preoccupation with the experience he, as a Red Army soldier, endured upon taking part in liberation of the concentration camps Majdanek and Auschwitz. Shocked by the actual sights he witnessed, he depicted Jesus as an actual camp inmate, wearing a striped uniform marked by every possible defamation sign – the Jewish yellow star, the red triangle of political prisoners, and the individual prison number, the numerical tattoo on his lower arm can also be seen. The different stages of camp life are portrayed as the traditional Passion of Christ. While showing the actual situations the artist based himself upon the well known European Renaissance paintings canonically depicting Jesus‘ suffering. The article places Tolkatchev‘s series in a broader cultural and visual context by exploring the development of the ‘historical Jesus’ in the 19th century European thought and Russian realist art, and by examining the impact of the German avant-garde. By doing so, a deeper understanding of the universal message Tolkatchev’s works entail is offered.
Mentoring in a Digital World
(2015)
This paper focuses on the results of the evaluation of the first
pilot of an e-mentoring unit designed by the Hands-On ICT consortium,
funded by the EU LLL programme. The overall aim of this two-year
activity is to investigate the value for professional learning of Massive
Online Open Courses (MOOCs) and Community Online Open Courses
(COOCs) in the context of a ‘community of practice’. Three units in the
first pilot covered aspects of using digital technologies to develop creative
thinking skills. The findings in this paper relate to the fourth unit
about e-mentoring, a skill that was important to delivering the course
content in the other three units. Findings about the e-mentoring unit
included: the students’ request for detailed profiles so that participants
can get to know each other; and, the need to reconcile the different
interpretations of e-mentoring held by the participants when the course
begins. The evaluators concluded that the major issues were that: not all
professional learners would self-organise and network; and few would
wish to mentor their colleagues voluntarily. Therefore, the e-mentoring
issues will need careful consideration in pilots two and three to identify
how e-mentoring will be organised.
The objectives of this study were to examine (a) the effect
of dynamic assessment (DA) in a 3D Immersive Virtual Reality
(IVR) environment as compared with computerized 2D and noncomputerized
(NC) situations on cognitive modifiability, and (b) the
transfer effects of these conditions on more difficult problem solving
administered two weeks later in a non-computerized environment. A
sample of 117 children aged 6:6-9:0 years were randomly assigned
into three experimental groups of DA conditions: 3D, 2D, and NC, and
one control group (C). All groups received the pre- and post-teaching
Analogies subtest of the Cognitive Modifiability Battery (CMB-AN).
The experimental groups received a teaching phase in conditions similar
to the pre-and post-teaching phases. The findings showed that cognitive
modifiability, in a 3D IVR, was distinctively higher than in the two
other experimental groups (2D computer group and NC group). It was
also found that the 3D group showed significantly higher performance
in transfer problems than the 2D and NC groups.
In diesem Beitrag soll es darum gehen, anhand der Distinktion von Jetztzeit und Erinnerung scheinbare Einheiten im lyrischen Werk der Nelly Sachs zu hinterfragen. Ein Nexus der Jesusfigur zur Shoah ist in den Gedichten nicht zu übersehen; inwieweit eine Korrelation beider Diskurse zwischen dem perennierenden Leiden der Opfer und dem am Kreuz Gemarterten besteht, ist der Gegenstand dieser Untersuchung. Jesus wird im lyrischen Oeuvre auf der zeitlichen wie inhaltlichen Ebene neu figuriert: nicht als christologisch-dogmatische Erlöserfigur, sondern als der qualvoll gemarterte Mann, dessen Schrei im 20. Jahrhundert eine neue Lesbarkeit generiert: als leidender Mit-Bruder. Der historische Index der Jesus-Gestalt wird in der Passionsszenerie, die jedoch transformativ modifiziert wird, manifest.
WR Time Series Photometry
(2015)
We take a comprehensive look at Wolf Rayet photometric variability using the MOST satellite. This sample, consisting of 6 WR stars and 6 WC stars defies all typical photometric analysis. We do, however, confirm the presence of unusual periodic signals resembling sawtooth waves which are present in 11 out of 12 stars in this sample.
The study reported in this paper involved the employment
of specific in-class exercises using a Personal Response System (PRS).
These exercises were designed with two goals: to enhance students’
capabilities of tracing a given code and of explaining a given code in
natural language with some abstraction. The paper presents evidence
from the actual use of the PRS along with students’ subjective impressions
regarding both the use of the PRS and the special exercises. The
conclusions from the findings are followed with a short discussion on
benefits of PRS-based mental processing exercises for learning programming
and beyond.
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.
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.
As part of our ongoing Wolf-Rayet (WR) Magellanic Cloud survey, we have discovered 13 new WRs. However, the most exciting outcome of our survey is not the number of new WRs, but their unique characteristics. Eight of our discoveries appear to belong to an entirely new class of WRs. While one might naively classify these stars as WN3+O3V binaries, such a pairing is unlikely. Preliminary CMFGN modeling suggests physical parameters similar to early-type WNs in the Large Magellanic Cloud except with mass-loss rates three to five times lower and slightly higher temperatures. The evolution status of these stars remains an open question.
The Galactic Center (GC) hosts three of the most massive WR rich, resolved young clusters in the Local Group as well as a large number of apparently isolated massive stars. Therefore, it constitutes a test bed to study the star formation history of the region, to probe a possible top-heavy scenario and to address massive star formation (clusters vs isolation) in such a dense and harsh environment. We present results from our ongoing infrared spectroscopic studies of WRs and other massive stars at the Center of the Milky Way.
We investigate the rarity of the Wolf-Rayet X-ray binaries (WRXRBs) in contrast to their predecessors, the high mass X-ray binaries (HMXRBs). Recent studies suggest that common envelope (CE) mergers during the evolution of a HMXRBs may be responsible (Linden et al. 2012). We conduct a binary population synthesis to generate a population of HMXRBs mimicking the Galactic sample and vary the efficiency parameter during the CE phase to match the current WRXRB to HMXRB ratio. We find that ∼50% of systems must merge to match observational constraints.
I address uncertainties on the spatial distribution and mass of the dust formed in η Carinae's Homunculus nebula with data being combined from several space- and ground-based facilities spanning near-infrared to sub-mm wavelengths, in terms of observational constraints and modeling. Until these aspects are better understood, the mass loss history and mechanisms responsible for η Car's enormous eruption(s) remain poorly constrained.
Wolf-Rayet (WR) stars lose copious amounts of mass and momentum through dense stellar winds. The interaction of these outflows with their surroundings results in highly structured and complex circumstellar environments, often featuring knots, arcs, shells and spirals. Recent improvements in computational power and techniques have led to the development of detailed, multi-dimensional simulations that have given new insight into the origin of these structures, and better understanding of the physical mechanisms driving their formation. We review three of the main mechanisms that shape the outflows of WR stars:
• interaction with the interstellar medium (ISM), i.e., wind-ISM interactions;
• interaction with a stellar wind, either from a previous phase of evolution or the wind from a companion star, i.e., wind-wind interactions;
• and interaction with a companion star that has a weak or insignificant outflow (e.g., a compact companion such as a neutron star or black hole), i.e.,wind-companion interactions.
We also highlight the broader implications and impact of these circumstellar structures for related phenomena, e.g., for X-ray binaries and Gamma-ray bursts.
Although we all use the name Wolf-Rayet to refer to specific groups of stars, “Wolf-Rayet” per se is really an astrophysical phenomenon of fast-moving, hot plasma, normally expanding around a hot star. However, expediency demands that we follow established traditions by referring to three specific kinds of WR stars: (1) cWR, “classical” He-burning descendants of massive, O-type stars, presumably all of which pass through a WR stage; (2) WNh, the most massive and luminous hydrogen-rich main-sequence stars with strong winds; and (3) [WR], the central stars of some 15 % of Planetary Nebulae. Wolf-Rayet stars are the epitome of relatively stable stars with the highest mass-loss rates for their kind. It behooves us to understand the what, how and why of this circumstance, along with its manyfold and fascinating consequences.
Nearly 50 post-common-envelope (post-CE) close binary central stars of planetary nebulae (CSPNe) are now known. Most contain either main sequence or white dwarf (WD) companions that orbit the WD primary in around 0.1–1.0 days. Only PN G222.8–04.2 and NGC 5189 have post-CE CSPNe with a Wolf-Rayet star primary (denoted [WR]), the low-mass analogues of massive Wolf-Rayet stars. It is not well understood how H-deficient [WR] CSPNe form, even though they are relatively common, appearing in over 100 PNe. The discovery and characterisation of post-CE [WR] CSPNe is essential to determine whether proposed binary formation scenarios are feasible to explain this enigmatic class of stars. The existence of post-CE [WR] binaries alone suggests binary mergers are not necessarily a pathway to form [WR] stars. Here we give an overview of the initial results of a radial velocity monitoring programme of [WR] CSPNe to search for new binaries. We discuss the motivation for the survey and the associated strong selection effects. The mass functions determined for PN G222.8–04.2 and NGC 5189, together with literature photometric variability data of other [WR] CSPNe, suggest that of the post-CE [WR] CSPNe yet to be found, most will have WD or subdwarf O/B-type companions in wider orbits than typical post-CE CSPNe (several days or months c.f. less than a day).
Participants of this workshop will be confronted exemplarily
with a considerable inconsistency of global Informatics education at
lower secondary level. More importantly, they are invited to contribute
actively on this issue in form of short case studies of their countries.
Until now, very few countries have been successful in implementing
Informatics or Computing at primary and lower secondary level. The
spectrum from digital literacy to informatics, particularly as a discipline
in its own right, has not really achieved a breakthrough and seems to
be underrepresented for these age groups. The goal of this workshop
is not only to discuss the anamnesis and diagnosis of this fragmented
field, but also to discuss and suggest viable forms of therapy in form of
setting educational standards. Making visible good practices in some
countries and comparing successful approaches are rewarding tasks for
this workshop.
Discussing and defining common educational standards on a transcontinental
level for the age group of 14 to 15 years old students in a readable,
assessable and acceptable form should keep the participants of this
workshop active beyond the limited time at the workshop.
Key physical ingredients governing the evolution of massive stars are mass losses, convection and mixing in radiative zones. These effects are important both in the frame of single and close binary evolution. The present paper addresses two points: 1) the differences between two families of rotating models, i.e. the family of models computed with and without an efficient transport of angular momentum in radiative zones; 2) The impact of the mass losses in single and in close binary models.
Ring Nebulae
(2015)
Preliminary results are presented from spectroscopic data in the optical range of the Galactic ring nebulae NGC 6888, G2:4+1:4, RCW 58 and Sh2-308. Deep observations with long exposure times were carried out at the 6.5m Clay Telescope and at the 10.4m Gran Telescopio Canarias. In NGC 6888, recombination lines of C ii, O ii and N ii are detected with signal-to-noise ratios higher than 8. The chemical content of NGC 6888 is discussed within the chemical enrichment predicted by evolution models of massive stars. For all nebulae, a forthcoming work will content in-depth details about observations, analysis and final results (Esteban et al. 2015, in prep.).
Helium stars
(2015)
There are outstanding problems in trying to reproduce the observed nature of Wolf–Rayet stars from theoretical stellar models. We have investigated the effects of uncertainties, such as composition and mass-loss rate, on the evolution and structure of Wolf–Rayet stars and their lower mass brethren. We find that the normal Conti scenario needs to be altered, with different WR types being due to different initial masses as well as different stages of evolution.
We summarize past and current surveys for WRs among the Local Group galaxies, empha- sizing both the why and how. Such studies are invaluable for helping us learn about massive star evolution, and for providing sensitive tests of the stellar evolution models. But for such surveys to be useful, the completeness limits must be well understood. We illustrate that point by following the “evolution” of the observed WC/WN ratio in nearby galaxies. We end by examining our new survey for WR stars in the Magellanic Clouds, which has revealed a new type of WN star, never before seen.
We present results of investigation of spectral variability of one of the most interesting massive stars, Romano's star (M33/V532 or GR290), located in the M33 galaxy. Brightness of the star changes together with its spectral class, which varies from WN11 to WN8. Using CMFGEN code we estimated parameters of stellar atmosphere and found that during last ten years bolometric luminosity of the star changed synchronously with stellar magnitude. Our calculations argue in favor of the hypothesis of a post-LBV status of GR290.
Die Beziehungen zwischen den Vereinten Nationen und nichtstaatlichen Akteuren
haben seit den 1990er Jahren einen radikalen Wandel erlebt. Nach der
Rio-Konferenz über Umwelt und Entwicklung 1992 stand in den Vereinten Nationen
zunächst die Frage im Vordergrund, wie der gewachsenen Bedeutung
der Nichtregierungsorganisationen (NGOs) in der Arbeit und den Strukturen der
Weltorganisation Rechnung getragen werden könnte. Seit Ende der 1990er Jahre
dominierten innerhalb der Vereinten Nationen und einiger ihrer Spezialorgane
und Sonderorganisationen zunehmend die Bemühungen, Privatunternehmen
und ihre Interessenvertreter aktiver in die Arbeit der Vereinten Nationen zu integrieren.
Dies geschah zum einen in Form unterschiedlichster bilateraler Kontakte
und Kooperationsvorhaben zwischen Unternehmen und UN-Akteuren, zum anderen
im Rahmen von Dialogveranstaltungen und gemeinsamen Initiativen von
Regierungen, zwischenstaatlichen Gremien, Wirtschaftsvertretern und NGOs, für
die im Folgeprozess der Rio-Konferenz der Begriff der Multistakeholder-Partnerschaften
geprägt wurde.
Der folgende Beitrag nimmt diese Entwicklung kritisch unter die Lupe. Er
zeichnet im Zeitraffer nach, wie sich die Beziehungen zwischen den Vereinten
Nationen und nichtstaatlichen Akteuren gewandelt haben, beschreibt das Ausmaß
und die Bandbreite der neuen Partnerschaftsansätze, erörtert Risiken und
Nebenwirkungen dieses Paradigmenwechsels in der internationalen Politik und
skizziert zum Schluss, welche Konsequenzen sich daraus für die Vereinten Nationen
abzeichnen.
The total population of Wolf-Rayet (WR) stars in the Galaxy is predicted by models to be as many as ~6000 stars, and yet the number of catalogued WR stars as a result of optical surveys was far lower than this (~200) at the turn of this century. When beginning our WR searches using infrared techniques it was not clear whether WR number predictions were too optimistic or whether there was more hidden behind interstellar and circumstellar extinction. During the last decade we pioneered a technique of exploiting the near- and mid-infrared continuum colours for individual point sources provided by large-format surveys of the Galaxy, including 2MASS and Spitzer/GLIMPSE, to pierce through the dust and reveal newly discovered WR stars throughout the Galactic Plane. The key item to the colour discrimination is via the characteristic infrared spectral index produced by the strong winds of the WR stars, combined with dust extinction, which place WR stars in a relatively depopulated area of infrared colour-colour diagrams. The use of the Spitzer/GLIMPSE 8µm and, more recently, WISE 22µm fluxes together with cross-referencing with X-ray measurements in selected Galactic regions have enabled improved candidate lists that increased our confirmation success rate, achieved via follow-up infrared and optical spectroscopy. To date a total of 102 new WR stars have been found with many more
candidates still available for follow-up. This constitutes an addition of ~16% to the current
inventory of 642 Galactic WR stars. In this talk we review our methods and provide some
new results and a preliminary review of their stellar and interstellar medium environments. We provide a roadmap for the future of this search, including statistical modeling, and what we can add to star formation and high mass star evolution studies.
We investigate the ergodic properties of a random walker performing (anomalous) diffusion on a random fractal geometry. Extensive Monte Carlo simulations of the motion of tracer particles on an ensemble of realisations of percolation clusters are performed for a wide range of percolation densities. Single trajectories of the tracer motion are analysed to quantify the time averaged mean squared displacement (MSD) and to compare this with the ensemble averaged MSD of the particle motion. Other complementary physical observables associated with ergodicity are studied, as well. It turns out that the time averaged MSD of individual realisations exhibits non-vanishing fluctuations even in the limit of very long observation times as the percolation density approaches the critical value. This apparent non-ergodic behaviour concurs with the ergodic behaviour on the ensemble averaged level. We demonstrate how the non-vanishing fluctuations in single particle trajectories are analytically expressed in terms of the fractal dimension and the cluster size distribution of the random geometry, thus being of purely geometrical origin. Moreover, we reveal that the convergence scaling law to ergodicity, which is known to be inversely proportional to the observation time T for ergodic diffusion processes, follows a power-law ∼T−h with h < 1 due to the fractal structure of the accessible space. These results provide useful measures for differentiating the subdiffusion on random fractals from an otherwise closely related process, namely, fractional Brownian motion. Implications of our results on the analysis of single particle tracking experiments are provided.
How does the Implementation of a Literacy Learning Tool Kit influence Literacy Skill Acquisition?
(2015)
This study aimed at following how teachers transfer skills
into results while using ABRA literacy software. This was done in
the second part of the pilot study whose aim was to provide equity to
control group teachers and students by exposing them to the ABRACADABRA
treatment after the end of phase 1. This opportunity was
used to follow the phase 1 teachers to see how the skills learned were
being transformed into results. A standard three-day initial training and
planning session on how to use ABRA to teach literacy was held at the
beginning of each phase for ABRA teachers (phase 1 experimental and
phase 2 delayed ABRA). Teachers were provided with teaching materials
including a tentative ABRA curriculum developed to align with the
Kenyan English Language requirements for year 1 and 3 students. Results
showed that although there was no significant difference between
the groups in vocabulary-related subscales which include word reading
and meaning as well as sentence comprehension, students in ABRACADABRA
classes improved their scores at a significantly higher rate
than students in control classes in comprehension related scores. An
average student in the ABRACADABRA group improved by 12 and
16 percentile points respectively compared to their counterparts in the
control group.
As a result of the Bologna reform of educational systems in
Europe the outcome orientation of learning processes, competence-oriented
descriptions of the curricula and competence-oriented assessment
procedures became standard also in Computer Science Education
(CSE). The following keynote addresses important issues of shaping
a CSE competence model especially in the area of informatics system
comprehension and object-oriented modelling. Objectives and research
methodology of the project MoKoM (Modelling and Measurement
of Competences in CSE) are explained. Firstly, the CSE competence
model was derived based on theoretical concepts and then secondly the
model was empirically examined and refined using expert interviews.
Furthermore, the paper depicts the development and examination of
a competence measurement instrument, which was derived from the
competence model. Therefore, the instrument was applied to a large
sample of students at the gymnasium’s upper class level. Subsequently,
efforts to develop a competence level model, based on the retrieved empirical
results and on expert ratings are presented. Finally, further demands
on research on competence modelling in CSE will be outlined.
In the project MoKoM, which is funded by the German
Research Foundation (DFG) from 2008 to 2012, a test instrument
measuring students’ competences in computer science was developed.
This paper presents the results of an expert rating of the levels of
students’ competences done for the items of the instrument.
At first we will describe the difficulty-relevant features that were
used for the evaluation. These were deduced from computer science,
psychological and didactical findings and resources. Potentials and
desiderata of this research method are discussed further on. Finally
we will present our conclusions on the results and give an outlook on
further steps.
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.
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.
Networking knowledge
(2015)
Global citizenship and diversity are well-represented concepts in today’s higher education. Learning outcomes and competencies are designed to sensitize students to the many cultural backgrounds of U.S. learning institutions. Nevertheless, true globality, as represented through diverse discourses and perspectives of the world, still seems neglected in curricula and course assignments. This article explores the possibilities offered through a new shared space in education where different forms of networked knowledge and multifaceted perspectives can build a global platform of exchange in a diverse student population. The universal science concept described by Alexander von Humboldt at the beginning of the 19th Century illuminates this intertwined approach to knowledge of the world, which has the potential to positively impact contemporary curricula and course design. Von Humboldt’s writings emphasize inclusion and interplay among cultures and natural phenomena. By inviting our students to be active representatives of diverse discourses, these interconnecting links will become more transparent. In turn, productive forms of knowing about the world may enrich current learning objectives and thereby reflect a true global citizenship as it evolves in a new shared space of education. Keywords: global citizenship, plurality, diverse discourses, multicultural education.
Wolf-Rayet stars are important sources for the enrichment of the ISM with nuclear processed elements, UV photons and momentum. They are descendants of high-mass stars for which short lifetimes and transition times can hamper the spectral classification of the stars in their different evolutionary phases. The expanded stellar atmospheres of Wolf-Rayet stars can show spectra which seem inconsistent with the anticipated underlying evolution phase, for example in late hydrogen-burning WN stars and Of/WN transition stars. We present a sequence of synthetic spectra of the Potsdam Wolf-Rayet models based on the latest Geneva stellar evolution models. This will visualize the changes in stellar spectra over a full stellar lifetime. Direct comparison with observed stellar spectra, as well as the evolution of diagnostic line ratios will improve the connection of spectral classification and evolution phase.
The growing impact of globalisation and the development of
a ‘knowledge society’ have led many to argue that 21st century skills are
essential for life in twenty-first century society and that ICT is central
to their development. This paper describes how 21st century skills, in
particular digital literacy, critical thinking, creativity, communication
and collaboration skills, have been conceptualised and embedded in the
resources developed for teachers in iTEC, a four-year, European project.
The effectiveness of this approach is considered in light of the data
collected through the evaluation of the pilots, which considers both the
potential benefits of using technology to support the development of
21st century skills, but also the challenges of doing so. Finally, the paper
discusses the learning support systems required in order to transform
pedagogies and embed 21st century skills. It is argued that support is
required in standards and assessment; curriculum and instruction; professional
development; and learning environments.
Es wird ein umfassendes Mentoring Konzept im Studiengang Informatik an der RWTH Aachen vorgestellt, das den Übergang von der Schule zur Universität unterstützt und gleichzeitig beim Auftreten von Schwierigkeiten im Verlauf des Studiums effiziente und kompetente Beratung bietet. Das Programm erreicht durchgängig hohe Akzeptanzwerte bei den Studierenden trotz verpflichtender Teilnahme im ersten Semester. Die Wirksamkeit des Programms ist durch die zahlreichen einflussgebenden Variablen zwar rein quantitativ kaum messbar, die Möglichkeit auf organisatorische und fachliche Probleme eines Jahrgangs reagieren zu können sowie einen Einblick auf die Gründe für einen Studienabbruch zu bekommen, bestätigt aber die Notwendigkeit der Maßnahme.
Die jüdischen Künstler Maurycy Gottlieb (1856–1879) und Marc Chagall (1887–1985) stellten Jesus als gläubigen Juden, eingebettet in die jüdische Umwelt seiner Zeit, dar. Der jüdische Jesus wird für sie zu einer Auseinandersetzung mit den jüdischen Wurzeln des Christentums und mit dem Antisemitismus, und sein Martyrium zu einem Symbol des jüdischen Leidens. Der vorliegende Aufsatz untersucht, wie ihre Bilder diese Botschaften transportieren und analysiert Kontinuitäten und Brüche über einen langen Zeitraum hinweg.
The stellar Eddington limit
(2015)
It is often assumed that when stars reach their Eddington limit, strong outflows are initiated, and that this happens only for extreme stellar masses. We discuss here that in models of up to 500 M⊙, the Eddington limit is never reached at the stellar surface. Instead, we argue that the Eddington limit is reached inside the stellar envelope in hydrogen-rich stars above ∼ 30 M⊙ and in Wolf-Rayet stars above ∼ 7 M⊙, with drastic effects for their struture and stability.
In diesem Text soll zweierlei gezeigt werden. Erstens, weil Menschen Rechte haben, gibt es wenigstens einige Tiere, die Rechte haben (I.). Zweitens, wir können die Rechte von Tieren nicht willkürfrei auf die Art begrenzen, die wir selber bilden; Menschen sind nicht die einzigen Tiere, die Rechte haben (II.).
We study the interaction of line-driven winds from massive stars with the magnetic field rooted in these stars by carrying out numerical simulations using the Nirvana MHD code in 2D in spherical polar coordinates. The code's adaptive mesh refinement feature allows high spatial resolution across the whole simulation box. We study both O and Wolf-Rayet stars for a range of magnetic field strengths from weak to strong as measured by the confinement parameter. For weak fields our simulations show that the initially dipolar field opens up far away from the star and a thin disk-like structure forms in the equatorial plane of the magnetic field. For stronger fields the disk is disrupted close to the stellar surface and closed field lines persist at low latitudes. For very strong fields a pronounced magnetosphere forms where the gas is forced to move along the field lines and eventually falls back to the stellar surface.
Der folgende Artikel beschreibt die Evaluation eines Lehrvideos zum informatischen Problemlösen, welches auf der Grundlage einer Vergleichsstudie mit starken und schwachen Problemlösern entwickelt wurde. Beispielhaft wird in dem Film ein Färbeproblem durch einen fiktiven Hochleister unter lautem Denken gelöst, die einzelnen Arbeitsschritte werden abschnittsweise kommentiert und erklärt. Ob dieses Lernkonzept von Studenten akzeptiert wird und sich durch Anschauen des Videos tatsächlich ein Lerneffekt einstellt, wurde durch eine Befragung und eine erste Vergleichsstudie untersucht.
Humboldts Hefte
(2015)
Der 2013 geglückte Ankauf der Amerikanischen Tagebücher durch ein Konsortium öffentlicher und privater Geldgeber hat es nicht nur ermöglicht, Alexander von Humboldts Reisemanuskripte zum ersten Mal einer breiten interessierten Öffentlichkeit vorzustellen, sondern wirft auch ein besonderer Licht auf die Geschichte ihrer Rezeption und Erforschung. Welche Phasen der Arbeit und Auswertung der Tagebücher lassen sich nachzeichnen? Und an welchem Punkt steht die Humboldt-Forschung in dieser Frage heute?
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.
Der deutsch-jüdische Dichter und Anarchist Erich Mühsam (1878–1934) rekurrierte in seinem schriftstellerischen OEuvre wiederholt auf die Figur Jesus’. Im Versuch, diese Beziehungsgeschichte zu rekonstruieren und zu deuten, rücken Einflussgeber aus dem Umfeld der literarischen Avantgarde Berlins sowie der Lebensreformbewegung in den Blick. In einer Verschränkung von quasireligiöser Renaissance und Aufbruchstimmung hin zum ‚Neuen Menschen‘ war Jesus in diesen Zirkeln um die Jahrhundertwende ein beliebtes Motiv und prägte sich, vermittelt über Freundschaften und Wegmarken, auch in Mühsams Schreiben ein. Neben Kain ist es Jesus, der bei Mühsam zur den fünften Stand revolutionierenden Lichtgestalt wird. In diese Bezugnahme spielen Mühsams konfliktreiches Verhältnis zu seinem Vater und dessen Assimilation an das deutsche Bürgertum mit hinein, das keineswegs gänzlich jene aufgeklärten Werte lebte, auf die es sich nominell berief: Statt Freiheit und Gleichheit prävalierten neue Zwänge, Begrenzungen und Ressentiments, wie Mühsam bemerkte. Über Gustav Landauer fand er nicht nur zum Anarchismus, sondern auch zu einer neuen Sprache für die verschüttete Tradition und prägte hierüber seiner Jesusfigur sein Verständnis eines rebellischen Judentums ein, das Mühsam selbst als Revolutionär verkörperte.
HD5980
(2015)
HD5980 is a multiple system containing at least 3 very massive and luminous stars. Located in the Small Magellanic Cloud, it is an ideal system for studying the massive star structure and evolutionary processes in low-metallicity environments. Intensely observed over the past few decades, HD5980 is a treasure trove of information on stellar wind structure, on wind-wind collisions and on the formation of wind-blown circumstellar structures. In addition, its characteristics suggest that the eclipsing WR+LBV stars of the system are the product of quasihomogeneous chemical evolution, thus making them candidate pair production supernovae or GRB progenitors. This paper summarizes some of the outstanding results derived from half a century of observations and recent theoretical studies.
We present the results of the new photometric observations of the famous hypergiant PCygni. New observations were obtained in 2014 using the 48 cm Cassegrain telescope of the Abastumani Astrophysical Observatory, Georgia. We reveal some interesting behaviors of the B,V,R,I light curves, and also report new results on the periodicity of PCygni's variation. The latter result is based on the analysis of the photometric data (U,B,V filters) collected at the Abastumani Observatory between 1937 and 1983.
PopIII-star siblings in IZw18 and metal-poor WR galaxies unveiled from integral field spectroscopy
(2015)
Here, we highlight our recent results from the IFS study of Mrk178, the closest metal-poor WR galaxy, and of IZw18, the most metal-poor star-forming galaxy known in the local Universe. The IFS data of Mrk178 show the importance of aperture effects on the search for WR features, and the extent to which physical variations in the ISM properties can be detected. Our IFS data of IZw18 reveal its entire nebular HeIIλ4686-emitting region, and indicate for the very first time that peculiar, hot (nearly) metal-free ionizing stars (called here PopIII-star siblings) might hold the key to the HeII-ionization in IZw18.
This paper discusses results from a small-scale research
study, together with some recently published research into student
perceptions of ICT for learning in schools, to consider relevant skills
that do not appear to currently being taught. The paper concludes by
raising three issues relating to learning with and through ICT that need
to be addressed in school curricula and classroom teaching.
Der Beitrag stellt das Konzept des Semantischen Positionierens als eine Möglichkeit vor, Grundformen des wissenschaftlichen Arbeitens und elementare Formen der diskursiven Auseinandersetzung zu vermitteln, ohne dass die Studierenden sich inhaltlich an der aktuellen Forschung beteiligen müssten. Die Umsetzung dieses Konzepts im Bachelorstudium der Informatik verdeutlicht, dass mit diesem Ansatz sowohl die Kompetenzen für den Übergang in den mehr forschungsgetriebenen Masterstudiengang als auch für die berufliche Wissensarbeit erworben werden können.
IT EnGAGES!
(2015)
Durch den Einsatz von Spielen und Spielelementen in Lernkontexten wird versucht, Lernende zur Beschäftigung mit den Lerninhalten zu motivieren. Spielerische Elemente haben allerdings nicht nur positive motivationale Effekte: Sie können sich beispielsweise negativ auf die intrinsische Motivation auswirken, und auch nicht jeder Lernende spielt gerne. Um negativen Einflüssen von Gamification entgegenzuwirken, wurde ein Toolkit für adaptierbare Lernumgebungen entwickelt. Damit erzeugte Lernumgebungen erlauben es Studierenden, den Grad der Gamification selbst zu bestimmen, indem Spielelemente an- und abgeschaltet werden. Im Rahmen einer Anfängerprogrammiervorlesung wurden Lernspielaufgaben aus den existierenden, optionalen interaktiven eTests entwickelt und Studierenden als zusätzliche Lerngelegenheit angeboten. Eine erste explorative Studie bestätigt die Vermutung, dass die Akzeptanz des adaptierbaren Lernspiels sehr hoch ist, es aber dennoch Studierende gibt, welche die Lernumgebung ohne Spielelemente durcharbeiten. Somit bietet adaptierbare Gamification verschiedenen Studierenden die Möglichkeit, sich zusätzliche motivationale Anreize durch Zuschalten von Spielelementen zu verschaffen, ohne dabei zum Spielen „genötigt“ zu werden.
Carl Einsteins Drama „Die schlimme Botschaft“ (1921), das ihm einen Prozess wegen Gotteslästerung einbrachte, steht mit seiner kritischen Haltung gegenüber der christlichen Lehre von der Kreuzigung und Auferstehung im Trend einer seinerzeit von jüdischen Theologen geführten Diskussion mit Adolf Harnacks Modernisierungsprojekt des Christentums. Jüdische Theologen wie Joseph Eschelbacher entwarfen ein Judentum, das, anders als von Harnack dargestellt, bereits jene moderne Gestalt einer Religion erfüllt, die Harnack für das Christentum erst zu erreichen versuchte. Einsteins „vom Dogma abweichende[r] Standpunkt“, der ihm vor Gericht von einem katholischen Geistlichen als Standpunkt eines dissidenten Juden vorgeworfen wurde, hätte durchaus als Beitrag eines jüdischen Literaten zur Apologie des Judentums gelten können, wenn Einstein nicht selbst seine Glaubensbrüder im Verbund mit der von ihm abgelehnten bürgerlichen Ideologie des kapitalistischen Marktes gesehen hätte.
Because most massive stars have been or will be affected by a companion during the course of their evolution, we cannot afford to neglect binaries when discussing the progenitors of supernovae and GRBs. Analyzing linear polarization in the emission lines of close binary systems allows us to probe the structures of these systems' winds and mass flows, making it possible to map the complex morphologies of the mass loss and mass transfer structures that shape their subsequent evolution. In Wolf-Rayet (WR) binaries, line polarization variations with orbital phase distinguish polarimetric signatures arising from lines that scatter near the stars from those that scatter far from the orbital plane. These far-scattering lines may form the basis for a "binary line-effect method" of identifying rapidly rotating WR stars (and hence GRB progenitor candidates) in binary systems.