729 research outputs found
MetroCinevision : Kino in der U-Bahn
Als die BrĂŒder LumiĂšre im Jahre 1895 in Paris auf einer Leinwand zeigten, wie ein Zug in den Bahnhof einfĂ€hrt, da kroch das Publikum - jedenfalls lautet so das GerĂŒcht - vor lauter Schrecken unter die Sitze, aus Angst, ĂŒberrollt zu werden. Seitdem hat das Kino nicht aufgehört, bei seinen Zuschauern starke GefĂŒhle auszulösen: mit Sex und Gewalt, mit hemmungsloser RĂŒhrseligkeit, mit witzigen Gags und Helden, die stets gröĂer sind als im "wirklichen" Leben. Alte Emotionen wurden im Laufe der Jahre in immer neue, mehr oder weniger lukrative Storys gepackt. Die rasant fortschreitende Technik lieĂ bald nicht mehr nur schwarz-weiĂe, sondern auch bunte Bilder auf den LeinwĂ€nden dieser Welt erscheinen. Doch all den technischen Neuerungen zum Trotz: Das Grundschema des Films ist ĂŒber all die Jahre das gleiche geblieben: Die Bilder bewegen sich, der Betrachter sitzt und sieht
Reorganization in complex landscapes: causes and consequences of changes in meta-food-webs
We lack a thorough understanding of the ecological processes, like species interactions and dispersal, that mediate the ecological responses of whole ecosystems to global changes, and their variability in realistically complex ecosystems. These processes involve multiple interacting species that move freely about the landscapes and thus, understanding these processes demands measures that can account for this complexity, at both the local and landscape scale. I address this issue by combining the local population dynamics of complex food webs and their metacommunity dynamics (yielding so called meta-food-webs). This allows me to incorporate real-world complexity for both local and spatial processes to examine how food webs respond to global changes, focusing on land use changes that alter the spatial configuration of habitats. To delve into the underlying mechanisms governing the impacts of global changes on multitrophic communities in complex landscapes, and to explore variations in these responses among species, trophic groups, landscapes and global change drivers, I develop new theoretical frameworks in which I combine ecology and mathematics. I demonstrate that local and spatial processes mediate meta-food-web responses to global changes in complex landscapes. Specifically, I show that there is a strong trophic dependency in the response of species to land use changes and emphasize that especially (large-bodied) consumer species at high trophic positions have elevated extinction risks when habitat becomes increasingly isolated (research chapters 1 and 2). In research chapter 3, by jointly considering multiple aspects of global change (land use changes and biological invasions), I demonstrate the interdependence of different environmental stressors. Overall, this thesis presents a major step towards a clearer understanding of food web responses to global change impacts
Large Scales - Long Times: Adding High Energy Resolution to SANS
The Neutron Spin Echo (NSE) variant MIEZE (Modulation of IntEnsity by Zero
Effort), where all beam manipulations are performed before the sample position,
offers the possibility to perform low background SANS measurements in strong
magnetic fields and depolarising samples. However, MIEZE is sensitive to
differences \DeltaL in the length of neutron flight paths through the
instrument and the sample. In this article, we discuss the major influence of
\DeltaL on contrast reduction of MIEZE measurements and its minimisation.
Finally we present a design case for enhancing a small-angle neutron scattering
(SANS) instrument at the planned European Spallation Source (ESS) in Lund,
Sweden, using a combination of MIEZE and other TOF options, such as TISANE
offering time windows from ns to minutes. The proposed instrument allows
studying fluctuations in depolarizing samples, samples exposed to strong
magnetic fields, and spin-incoherently scattering samples in a straightforward
way up to time scales of \mus at momentum transfers up to 0.01 {\AA}-1, while
keeping the instrumental effort and costs low.Comment: 5 pages, 8 figure
Identification of new regulators of the mitochondrial unfolded protein response in Caenorhabditis elegans mutants with defects in mitochondrial dynamics
Computational approaches for nuclear design analyses of the stellarator power reactor HELIAS
Der Helical-Axis Advanced Stellarator (HELIAS) ist ein konzeptioneller Entwurf eines nach dem Stellarator Konzept operierenden Fusionsleistungsreaktor, der vom Max-Planck-Institut fĂŒr Plasmaphysik (IPP) Greifswald mit einer thermischen Fusionsleistung von 3000 MW entwickelt wurde. Die Form des Stellarators ist durch nicht-planare Magnetfeldspulen charakterisiert, die ein Plasma einschlieĂendes Magnetfeld erzeugen. FĂŒr das HELIAS 5-B Reaktordesign wird eine erste umfassende Monte Carlo (MC) basierte Neutronik Designanalyse mit dem Monte Carlo N-Particle (MCNP) Strahlentransportcode durchgefĂŒhrt, um wichtigen nukleare KenngröĂen wie die Neutronenwandbelastung (NWL), die Neutronenflussverteilung, die Tritium-Brutrate (TBR) und das Abschirmvermögen zu ermitteln.
Die komplexe toroidal verdrillte HELIAS Stellaratorgeometrie wird vollstĂ€ndig durch OberflĂ€chen höherer Ordnung beschrieben, welche der Form des Magnetfeldes folgen und von einem CAD-Modell in ein MCNP-Modell ĂŒbertragen werden mĂŒssen. Es wurden drei verschiedene Möglichkeiten zur Geometriekonvertierung untersucht, wobei die facettierte Geometrie, die durch ein trianguliertes OberflĂ€chennetz auf der CAD-Geometrie im Direct Accelerated Geometry Monte Carlo (DAGMC) Ansatz als die vielversprechendste Option angesehen wird, da sie die komplexe Geometrie ohne EinschrĂ€nkungen nutzen kann.
FĂŒr die neutronenphysikalische Charakterisierung von HELIAS wurde das ursprĂŒngliche CAD-Modell in radialer Richtung in unterschiedliche funktionelle Schichten aufgeteilt und mit homogenisierten Materialmischungen gefĂŒllt, basierend auf dem Helium Cooled Pebble Bed (HCPB) Brutblanket Konzept, der StĂŒtzstruktur, dem VakuumbehĂ€lter und der Abschirmung. Die NWL Verteilung zeigt eine Variation der Belastung ĂŒber die gesamte erste Wand mit einer Spitzenlast von 1.93 MW/m^2 und einer Durchschnittslast von 0.95 MW/m^2. Die Neutronenflussverteilung hat einem maximalen Wert innerhalb der Plasmakammer von 4*10^14 n/cm^2/s, die durch das Blanket und den VakuumbehĂ€lter auf 10^10 n/cm^2/s abgeschwĂ€cht wird. Die TBR in dieser Konfiguration betrĂ€gt ~1.38; ein eher optimistischer Wert, welcher auf die Anwendung von homogenisierten Materialmischungen zurĂŒckzufĂŒhren ist.
Die Reaktorkomponenten mĂŒssen ein ausreichendes Abschirmvermögen aufweisen, um strahlungsempfindliche Bauteile zu schĂŒtzen. Die AbschwĂ€chung des Neutronenflusses um vier GröĂenordnungen durch die verwendete Abschirmung fĂŒhrt zur Erhöhung des statistischen Fehlers, der die Anwendung von Varianzreduktionsverfahren erforderlich macht. Die Abschirmberechnungen basierend auf der Technik der gitterbasierten Weight Window Verfahrens wurden in einem Bereich mit einem NWL von ~1.35 MW/m^2 und einer geringen radialen Baudicke von ~1.0 m durchgefĂŒhrt. Die fĂŒr den EU-Tokamak-Fusionsreaktor DEMO definierten Grenzwerte bezĂŒglich des Abschirmvermögens können von HELIAS in dem aktuellen Design nicht erfĂŒllt werden.Es wird deutlich, dass hier signifikante Verbesserungen der Abschirmung erforderlich sind, die durch die Erhöhung der radialen Abschirmungsschichtdicke und/oder der Anwendung fortschrittlicher Abschirmmaterialien erreichbar sind.
Die hier vorgestellte Arbeit prĂ€sentiert erstmals eine umfassende neutronenphysikalische Untersuchung eines auf dem Stellaratorprinzip beruhendem Leistungsreaktors am Beispiel des HELIAS-Designs, die auf einer verifizierten numerischen Methodik fĂŒr den Strahlungstransport basiert. Dieser Ansatz ist fĂŒr zukĂŒnftige neutronenphysikalische Anwendungen fĂŒr diesen Reaktortyp anwendbar. Er ermöglicht die Entwicklung optimierter Brutblanket-Konzepte und fortschrittlicher Strahlungsabschirmungen, die fĂŒr einen Fusionsreaktor unverzichtbar sind
Effect of Ozone/Oxygen-Pneumoperitoneum on Tumour Growth and Metastatic Spread of the Rabbit VX2 Head and Neck Cancer Model
About 6% of all newly diagnosed malignancies worldwide are cancers of the head and neck. They account for nearly 5% of all cancer-related deaths. Surgery, radiation therapy and chemotherapy as well as combinations of these three are currently regarded as the standard treatment. While high cure rates can be achieved for the early stage disease, cure and survival rates for locoregionally advanced and distant metastatic disease are still disappointing. Thus, the development of new treatment strategies is essential, particularly for the treatment of cancers with metastatic involvement of the lymph nodes.
The VX2 auricle carcinoma of New Zealand White rabbits (NZWR) is an accepted animal model for human head and neck cancers, since both are similar in growth leading to early regional lymph node metastases and subsequent distant metastatic spread. Ozone, 2002 recognized as a biomolecule since it was found to be endogenously produced by human neutrophils, exhibited protective effects in a rat sepsis model when insufflated intraperitoneally as a gas mixture with oxygen. This finding suggests that ozone might have immunemodulatory properties. In vitro, ozone was found to inhibit selectively the growth of human cancer cells. However, until now there are no randomized controlled trials that show a clear therapeutic effect of ozone on cancer disease.
The aim of this study was to test the effects of an intraperitoneally insufflated O3/O2 gas mixture (O3/O2-pneumoperitoneum, O3/O2-PP) on growth of the primary tumour and metastatic spread of the VX2 auricle cancer in NZWR. Fourteen days after inoculation of a VX2 tumour cell suspension into the subcutis of the right auricle rabbits were randomized to three experimental groups. The treatment was performed daily for five consecutive days, beginning on day 14 after tumour cell inoculation. Rabbits in Group A (n = 14, O3/O2 group) each day received an intraperitoneally insufflated volume of 80 ml/kg body weight of an O3/O2 gas mixture with an ozone concentration of 50 ÎŒg/ml gas mixture. Rabbits in Group B (n = 13, O2 group) received the same amount of pure oxygen and rabbits in Group C (n = 14, Sham group) were sham-treated. Arterial blood samples were taken on day 14 (prior to initiation of treatment) and on day 19 (after the last treatment) and standard haematological and clinical chemistry blood parameters were measured.
O3/O2-PP significantly increased the 3-month survival probability (50.0%) and the complete remission rate (42.9%) compared with sham treatment (7.1% 3-month survival probability and complete remission rate). The 3-month survival probability (23.1%) and complete remission rate (15.4%) of the rabbits that received pure medical oxygen were neither significantly different from the sham group nor from the O3/O2 group. All animals with complete remission of the primary tumour had an enlarged sentinel lymph node (parotid lymph node) at the beginning of the treatment period that regressed simultaneously. None of these rabbits had detectable lung metastases at day 90 on computed tomography scans of the thorax. No severe side effects could be detected except for a mild transient body weight loss and a mild leukocytosis pointing to O3/O2-PP as a relatively safe method. Animals of the O3/O2 group with complete tumour remission were resistant to the tumour cells after reinoculation of the tumour cell suspension. However, when treating these animals with dexamethasone and cyclosporin A, rabbits became susceptible to reinoculation of the tumour again. This indicates a crucial role of the immune system in tumour eradication with subsequent resistance to reimplantation.
However, prior to a potential clinical use of the O3/O2-PP method, further research is essential to clear up the exact mechanisms by which ozone exerts this antitumoural effects. Particularly, further clarification is needed regarding the dose response relationship, evaluation of yet undetected adverse effects and reproducibility of the results of the VX2 tumour model in other tumour model systems
Critical spin-flip scattering at the helimagnetic transition of MnSi
We report spherical neutron polarimetry (SNP) and discuss the spin-flip
scattering cross sections as well as the chiral fraction close to the
helimagnetic transition in MnSi. For our study, we have developed a
miniaturised SNP device that allows fast data collection when used in small
angle scattering geometry with an area detector. Critical spin-flip scattering
is found to be governed by chiral paramagnons that soften on a sphere in
momentum space. Carefully accounting for the incoherent spin-flip background,
we find that the resulting chiral fraction decreases gradually above the
helimagnetic transition reflecting a strongly renormalised chiral correlation
length with a temperature dependence in excellent quantitative agreement with
the Brazovskii theory for a fluctuation-induced first order transition.Comment: 5 pages, 3 figure
Macroeconomics modelling on UK GDP growth by neural computing
This paper presents multilayer neural networks used in UK gross domestic product estimation. These networks are trained by backpropagation and genetic algorithm based methods. Different from backpropagation guided by gradients of the performance, the genetic algorithm directly evaluates the performance of multiple sets of neural networks in parallel and then uses the analysed results to breed new networks that tend to be better suited to the problems in hand. It is shown that this guided evolution leads to globally optimal networks and more accurate results, with less adjustment of the algorithm needed
Analyzing Visual Mappings of Traditional and Alternative Music Notation
In this paper, we postulate that combining the domains of information
visualization and music studies paves the ground for a more structured analysis
of the design space of music notation, enabling the creation of alternative
music notations that are tailored to different users and their tasks. Hence, we
discuss the instantiation of a design and visualization pipeline for music
notation that follows a structured approach, based on the fundamental concepts
of information and data visualization. This enables practitioners and
researchers of digital humanities and information visualization, alike, to
conceptualize, create, and analyze novel music notation methods. Based on the
analysis of relevant stakeholders and their usage of music notation as a mean
of communication, we identify a set of relevant features typically encoded in
different annotations and encodings, as used by interpreters, performers, and
readers of music. We analyze the visual mappings of musical dimensions for
varying notation methods to highlight gaps and frequent usages of encodings,
visual channels, and Gestalt laws. This detailed analysis leads us to the
conclusion that such an under-researched area in information visualization
holds the potential for fundamental research. This paper discusses possible
research opportunities, open challenges, and arguments that can be pursued in
the process of analyzing, improving, or rethinking existing music notation
systems and techniques.Comment: 5 pages including references, 3rd Workshop on Visualization for the
Digital Humanities, Vis4DH, IEEE Vis 201
Shape optimization of structural parts in dynamic mechanical systems based on fatigue calculations
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