1,263 research outputs found
Chemo-dynamical Evolution of the ISM in Galaxies
Chemo-dynamical models have been introduced in the late eighties and are a
generally accepted tool for understanding galaxy evolution. They have been
successfully applied to one-dimensional problems, e.g. the evolution of
non-rotating galaxies, and two-dimensional problems, e.g. the evolution of disk
galaxies. Recently, also three-dimensional chemo-dynamical models have become
available. In these models the dynamics of different components, i.e. dark
matter, stars and a multi-phase interstellar medium, are treated in a
self-consistent way and several processes allow for an exchange of matter,
energy and momentum between the components or different gas phases. Some
results of chemo-dynamical models and their comparison with observations of
chemical abundances or star formation histories will be reviewed.Comment: 10 Pages, 5 Figures, to appear in "From Observations to
Self-Consistent Modelling of the ISM in Galaxies", 2003, eds M. Avillez et a
Reconstructing the Arches I: Constraining the Initial Conditions
We have performed a series of N-body simulations to model the Arches cluster.
Our aim is to find the best fitting model for the Arches cluster by comparing
our simulations with observational data and to constrain the parameters for the
initial conditions of the cluster. By neglecting the Galactic potential and
stellar evolution, we are able to efficiently search through a large parameter
space to determine e.g. the IMF, size, and mass of the cluster. We find, that
the cluster's observed present-day mass function can be well explained with an
initial Salpeter IMF. The lower mass-limit of the IMF cannot be well
constrained from our models. In our best models, the total mass and the virial
radius of the cluster are initially (5.1 +/- 0.8) 10^4 Msun and 0.76 +/- 0.12
pc, respectively. The concentration parameter of the initial King model is w0 =
3-5.Comment: 12 pages, 14 Figures, revised and accepted for publication in MNRA
SAPPORO: A way to turn your graphics cards into a GRAPE-6
We present Sapporo, a library for performing high-precision gravitational
N-body simulations on NVIDIA Graphical Processing Units (GPUs). Our library
mimics the GRAPE-6 library, and N-body codes currently running on GRAPE-6 can
switch to Sapporo by a simple relinking of the library. The precision of our
library is comparable to that of GRAPE-6, even though internally the GPU
hardware is limited to single precision arithmetics. This limitation is
effectively overcome by emulating double precision for calculating the distance
between particles. The performance loss of this operation is small (< 20%)
compared to the advantage of being able to run at high precision. We tested the
library using several GRAPE-6-enabled N-body codes, in particular with Starlab
and phiGRAPE. We measured peak performance of 800 Gflop/s for running with 10^6
particles on a PC with four commercial G92 architecture GPUs (two GeForce
9800GX2). As a production test, we simulated a 32k Plummer model with equal
mass stars well beyond core collapse. The simulation took 41 days, during which
the mean performance was 113 Gflop/s. The GPU did not show any problems from
running in a production environment for such an extended period of time.Comment: 13 pages, 9 figures, accepted to New Astronom
The Evolution and Implications of Entrepreneurship Curriculum at Universities
The notion of entrepreneurship is not a new one. Neither is the idea of entrepreneurship education. However, post-secondary entrepreneurship curriculum has exploded the past thirty five years. A number of reasons have helped to fuel this growth. An argument can be made that entrepreneurs can be made and are not born. Entrepreneurship education is the tool that encourages the transformation process. At the university level, most entrepreneurship curriculum is taught in business schools and colleges. Implications indicate that entrepreneurship education is good not only for students who become entrepreneurs. Entrepreneurship curriculum stimulates creativity and ownership, two traits desired by corporate America
Framework conditions and development potentials of (old) industrialised towns and regions in Central Europe - Utilising endogenous, place-based development potentials
This PhD discusses regional development in (old) industrial regions in Central Europe. It especially addresses regions which are predominantly characterised by small- and medium-sized towns. Such entities have not featured prominently in discussions of structural change and regional development over the past thirty to forty years. Interconnected, the work sheds light on the role of utilising endogenous place-based potentials as a way to create alternative development paths for such regions, by also taking into account multi-level governance arrangements and European cohesion funding.
The PhD is structured around 5 articles, which all have dealt with different aspects of regional development in Central European and were published between 2011 and 2020. These articles draw on a range of different case studies. To understand the underlying dynamics of regional development in such (old) industrial places, the work utilises a range of important theoretical concepts, including theories of uneven development, ânew regionalismâ, and interconnecting concepts of endogenous, place-based development potentials, as well as multi-level governance arrangements in an European context.
In its results, the PhD shows via the case-study regions how (old) industrial regions outside agglomeration areas are affected by processes of structural change and maps the challenges which they face creating new development paths. It highlights the fact that the processes of structural change can be all consuming, combining a range of economic, social and ecological elements. This affects regions, which often suffer already from low administrational and human capacities. Related to this, the work shows that especially local and regional development initiatives (fostered by multi-level governance settings) enable regions to develop new capacities and innovative development solutions.
Overall, the results of this PhD raise important questions on how to conceptualise and maintain long-term perspectives of regional development in the focus regions under European cohesion policies.Diese Dissertation befasst sich mit der Regionalentwicklung von (alt-)industriellen Regionen in Mitteleuropa. Sie fokussiert insbesondere auf solche Regionen, die ĂŒberwiegend von Klein- und MittelstĂ€dten geprĂ€gt sind und damit in der Diskussion um Strukturwandel und Regionalentwicklung in den vergangenen dreiĂig bis vierzig Jahren nicht im Vordergrund der Betrachtung standen. Dabei beleuchtet die Arbeit die Rolle endogener, ortsbezogener Potenziale als Möglichkeit, alternative Entwicklungspfade fĂŒr solche Regionen zu schaffen und berĂŒcksichtigt dabei insb. Multi-Level-Governance-Systeme und die europĂ€ische KohĂ€sionspolitik.
Die Dissertation basiert auf 5 Artikeln, die sich alle mit unterschiedlichen Aspekten der Regionalentwicklung in Mitteleuropa befassen und zwischen 2011 und 2020 veröffentlicht wurden. Sie stĂŒtzt sich dabei auf eine Reihe von unterschiedlichen Fallstudien aus ganz Mitteleuropa. Um die zugrundeliegende Dynamik der Regionalentwicklung in solchen (alt-)industriellen Orten besser zu verstehen, nutzt diese Arbeit eine Reihe theoretischer Konzepte, darunter Theorien der ungleichen Entwicklung, des "neuen Regionalismus", sowie damit zusammenhĂ€ngende Konzepte endogener, ortsbezogener Entwicklungspotenziale, sowie Multi-Level-Governance im europĂ€ischen Kontext.
Im Ergebnis zeigt die Dissertation anhand der diskutierten Fallstudien-Regionen, wie (alt-)industrielle Regionen auĂerhalb von AgglomerationsrĂ€umen von Prozessen des Strukturwandels betroffen sind und bildet die Herausforderungen ab, vor denen sie bei der Gestaltung neuer Entwicklungspfade stehen. Dabei wird hervorgehoben, dass die Wandlungssprozesse allumfassend sein können und oftmals eine Reihe von ökonomischen, sozialen und ökologischen Elementen vereinen. Dies findet oft in Regionen statt, die ohnehin mit nur geringen administrativen und personellen KapazitĂ€ten ausgestattet sind. In diesem Zusammenhang zeigt die Arbeit, dass es insbesondere lokale und regionale Entwicklungsinitiativen ermöglichen (gefördert durchKohĂ€sionspolitik und Multi-Level-Governance-Settings), neue KapazitĂ€ten und innovative Lösungen im Bezug auf regionale Entwicklung zu schaffen.
Insgesamt werfen die Ergebnisse dieser Doktorarbeit wichtige Fragen darĂŒber auf, wie langfristige Perspektiven fĂŒr die regionale Entwicklung in den Fokusregionen im Rahmen der europĂ€ischen KohĂ€sionspolitik geschaffen werden können
Post-mining potentials and redevelopment of former mining regions in Central Europe â Case studies from Germany and Slovenia
This article discusses the character of post-mining potentials and their role in regional development in a German and Slovenian mining region. The many possible uses often include renewable energies (biomass, geothermal energy), or tourism (museums). Discussing two case study regions, this article presents similarities and differences in approaches towards the utilisation of potentials, and compares factors that influence utilisation with reference to national framework conditions. The text argues that in the context of structural change and mine closures, the use of post-mining potentials, such as post-mining landscapes, infrastructures and traditions, can be a way to explore new development options for affected regions
Collisionally Regenerated Dark Matter Structures in Galactic Nuclei
We show that the presence of a râ3/2 dark matter overdensity can be robustly predicted at the center of any galaxy old enough to have grown a power-law density cusp in the stars via the Bahcall-Wolf mechanism. Using both Fokker-Planck and direct N-body integrations, we demonstrate collisional generation of these dark matter âcrestsâ (Collisionally REgenerated STtructures) even in the extreme case that the density of both stars and dark matter were previously lowered by slingshot ejection from a binary supermassive black hole. The time scale for collisional growth of the crest is approximately the two-body relaxation time as defined by the stars, which is . 10 Gyr at the centers of stellar spheroids with luminosities L . 109.5Lâ, including the bulge of the Milky Way. The presence of crests can robustly be predicted in such galaxies, unlike the steeper enhancements, called âspikesâ, produced by the adiabatic growth of black holes. We discuss special cases where the prospects for detecting dark matter annihilations from the centers of galaxy haloes are significantly affected by the formation of crests
Industrial heritage, cultural resources of current industries and creative pioneers
The paper deals with the framework conditions of Industrial Culture and the specific challenges in former industrialised towns outside agglomeration areas. To illustrate the use of Industrial Culture the paper gives a short Austrian example and finally discuss the main points about preservation and reactivation of industrial heritage
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