374 research outputs found
"Durch Methodenkombination ein Neuro-Forschungszentrum erster Güte" : Stefan Kieß im Gespräch mit Prof. Dr. Helmuth Steinmetz
Strong fields and neutral particle magnetic moment dynamics
Interaction of magnetic moment of point particles with external
electromagnetic fields experiences unresolved theoretical and experimental
discrepancies. In this work we point out several issues within the relativistic
quantum mechanics and the QED and we describe effects related to a new
covariant classical model of magnetic moment dynamics. Using this framework we
explore the invariant acceleration experienced by neutral particles coupled to
an external plane wave field through the magnetic moment: we study the case of
ultra relativistic Dirac neutrinos with magnetic moment in the range of
to ; and we address the case of slowly
moving neutrons. We explore how critical accelerations for neutrinos can be
experimentally achieved in laser-pulse interactions. The radiation of
accelerated neutrinos can serve as an important test distinguishing between
Majorana and Dirac nature of neutrinos.Comment: 8 page
Eye Tracking Evaluation Of Chinese Web Sites For The Chinese Market
This paper assesses and analyzes ways Chinese and European people view web sites designed in English and Chinese languages. The results suggest some similarities and differences based on different cultures.The Chinese market is gaining more and more importance in the international business arena. Due to the strong Chinese Internet growth rates increasingly more global enterprises use the Internet for e-Commerce, market penetration and expansion, and to communicate information in China. But the success of online communication with customers in the Chinese market is in many cases not as effective as planned, because of cultural differences between Chinese and European people. Specific reading behavior, different cultural color definitions, diverse meanings of symbols or pictures as well as differing Chinese attitudes and values have to be considered when designing web sites for China. To gain more knowledge about the needs, tastes and behavior styles from Chinese Internet users, an experiment was designed with the following hypothesis: Chinese and Europeans differ concerning web site evaluation and recognition due to culture. Web sites designed for Chinese (Mercedes, Sony Ericsson, and China Eastern) were tested using an Eye Tracking camera.Observation, using an Eye Tracking camera, combined with a survey, showed that Chinese users share only preferences like clarity and comprehensibility in web site quality with German users. Significant differences can be named concerning amount of information, design/color design and terminology. During the tests it also became clear that the order in which the Chinese users look at elements (navigation bar, text, pictures, etc.), and the tested recognition is not identical to European users.
The Milky Way and Andromeda galaxies in a constrained hydrodynamical simulation: morphological evolution
We study the two main constituent galaxies of a constrained simulation of the
Local Group as candidates for the Milky Way (MW) and Andromeda (M31). We focus
on the formation of the stellar discs and its relation to the formation of the
group as a rich system with two massive galaxies, and investigate the effects
of mergers and accretion as drivers of morphological transformations. We use a
state-of-the-art hydrodynamical code which includes star formation, feedback
and chemical enrichment to carry out our study. We run two simulations, where
we include or neglect the effects of radiation pressure from stars, to
investigate the impact of this process on the morphologies and star formation
rates of the simulated galaxies. We find that the simulated M31 and MW have
different formation histories, even though both inhabit, at z=0, the same
environment. These differences directly translate into and explain variations
in their star formation rates, in-situ fractions and final morphologies. The
M31 candidate has an active merger history, as a result of which its stellar
disc is unable to survive unaffected until the present time. In contrast, the
MW candidate has a smoother history with no major mergers at late times, and
forms a disc that grows steadily; at z=0 the simulated MW has an extended,
rotationally-supported disc which is dominant over the bulge. Our two feedback
implementations predict similar evolution of the galaxies and their discs,
although some variations are detected, the most important of which is the
formation time of the discs: in the model with weaker/stronger feedback the
discs form earlier/later. In summary, by comparing the formation histories of
the two galaxies, we conclude that the particular merger/accretion history of a
galaxy rather than its environment at the LG-scales is the main driver of the
formation and subsequent growth or destruction of galaxy discs.Comment: 12 pages, 7 figures, accepted for publication in A&
The Effect of Environment on Milky Way-mass galaxies in a Constrained Simulation of the Local Group
In this letter we present, for the first time, a study of star formation
rate, gas fraction and galaxy morphology of a constrained simulation of the
Milky Way (MW) and Andromeda (M31) galaxies, compared to other MW-mass
galaxies. By combining with unconstrained simulations we cover a sufficient
volume to compare these galaxies environmental densities ranging from the field
to that of the Local Group (LG). This is particularly relevant as it has been
shown that, quite generally, galaxy properties depend intimately upon their
environment, most prominently when galaxies in clusters are compared to those
in the field. For galaxies in loose groups such as the LG, however,
environmental effects have been less clear. We consider the galaxy's
environmental density in spheres of 1200 kpc (comoving) and find that whilst
environment does not appear to directly affect morphology, there is a positive
trend with star formation rates. This enhancement in star formation occurs
systematically for galaxies in higher density environments, regardless whether
they are part of the LG or in filaments. Our simulations suggest that the
richer environment at Mpc-scales may help replenish the star-forming gas,
allowing higher specific star formation rates in galaxies such as the MW.Comment: 6 pages, 4 figures, accepted to ApJ
Historische Entwicklung des Truppenübungsplatzes Allentsteig
Fokus dieser Arbeit soll es sein, den Truppenübungsplatz Allentsteig von seiner Errichtung bis zur heutigen Situation aufzurollen. Dabei wurde versucht, nicht nur seine militärische Funktion für das Österreichische Bundesheer niederzuschreiben, sondern vielmehr eine gesamtheitliche Analyse zu dokumentieren. Was ist nun damit gemeint?
Die Wichtigkeit des Übungsplatzes für militärische Zwecke steht außer Frage, doch müssen auch wirtschaftliche, organisatorische, ökologische und soziale Aspekte beachtet werden. Der Autor beschäftigte sich neben den Organisationsstrukturen des Truppenübungsplatzes auch damit, die Heeresforstverwaltung auf der einen und die wirtschaftlichen Verflechtungen mit der Stadt Allentsteig auf der anderen Seite zu analysieren. Es wurde auch versucht, ökologische Zusammenhänge im Zuge der Bearbeitung darzustellen, was die Auseinandersetzung mit der Naturschutzthematik widerspiegelt. Ebenso war es dem Autor ein Anliegen, die soziale Komponente nicht zu vernachlässigen. Bei Überlegungen, wie er diese in die Diplomarbeit integrieren könnte, wurde er darauf aufmerksam, dass die Einheitskommandanten des Aufklärungs- und Artilleriebataillons 4 in den meisten Fällen aus anderen Bundesländern stammen. Deshalb rückten soziale Beziehungen zwischen Soldaten anderer Bundesländer und der Waldviertler Bevölkerung in den Fokus.
Die Bearbeitung dieser eben aufgezählten Themen sollte den Lesern tiefere Einblicke in das Gebilde Truppenübungsplatz Allentsteig gewähren
Technologische Fundierung der Produktionsfunktion vom Typ D mit Hilfe von Verbrauchs- und Erzeugungsfunktionen
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First description of natural Echinococcus multilocularis infections in chinchilla ( Chinchilla laniger ) and Prevost's squirrel ( Callosciurus prevostii borneoensis )
This report describes for the first time the occurrence of alveolar echinococcosis in two exotic rodent species in Europe. A pet chinchilla (Chinchilla laniger) was euthanized due to a painful enlargement of the abdominal cavity, and a Prevost's squirrel (Callosciurus prevostii borneoensis) was found dead in the enclosure of a zoo. At necropsy, extended liver lesions consisting of small vesicles and cysts were observed in the livers of both animals. Histological examination revealed that these cysts were composed of an outer, homogenous, eosinophilic layer and an inner, cellular germinal layer. The cysts from both animals contained numerous protoscolices. The morphological diagnosis of Echinococcus multilocularis metacestode infections was confirmed by molecular mean
Mergers and the outside-in formation of dwarf spheroidals
We use a cosmological simulation of the formation of the Local Group to
explore the origin of age and metallicity gradients in dwarf spheroidal
galaxies. We find that a number of simulated dwarfs form "outside-in", with an
old, metal-poor population that surrounds a younger, more concentrated
metal-rich component, reminiscent of dwarf spheroidals like Sculptor or
Sextans. We focus on a few examples where stars form in two populations
distinct in age in order to elucidate the origin of these gradients. The
spatial distributions of the two components reflect their diverse origin; the
old stellar component is assembled through mergers, but the young population
forms largely in situ. The older component results from a first episode of star
formation that begins early but is quickly shut off by the combined effects of
stellar feedback and reionization. The younger component forms when a late
accretion event adds gas and reignites star formation. The effect of mergers is
to disperse the old stellar population, increasing their radius and decreasing
their central density relative to the young population. We argue that
dwarf-dwarf mergers offer a plausible scenario for the formation of systems
with multiple distinct populations and, more generally, for the origin of age
and metallicity gradients in dwarf spheroidals.Comment: 10 pages, 8 figures, Accepted for publication in MNRA
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