1,683 research outputs found

    KMOS Data Flow: Reconstructing Data Cubes in One Step

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    KMOS is a multi-object near-infrared integral field spectrometer with 24 deployable pick-off arms. Data processing is inevitably complex. We discuss specific issues and requirements that must be addressed in the data reduction pipeline, the calibration, the raw and processed data formats, and the simulated data. We discuss the pipeline architecture. We focus on its modular style and show how these modules can be used to build a classical pipeline, as well as a more advanced pipeline that can account for both spectral and spatial flexure as well as variations in the OH background. A novel aspect of the pipeline is that the raw data can be reconstructed into a cube in a single step. We discuss the advantages of this and outline the way in which we have implemented it. We finish by describing how the QFitsView tool can now be used to visualise KMOS data.Comment: Contribution to "Ground-based and Airborne Instrumentation for Astronomy III', SPIE 7735-254 (June 2010). High resolution version can be found at http://spiedl.or

    Epistemic Gaps and the Mind-Body Problem

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    This dissertation defends materialism from the epistemic arguments against materialism. Materialism is the view that everything is ultimately physical. The epistemic arguments against materialism claim that there is an epistemic gap between physical and phenomenal truths (for example, that knowing the physical truths does not put you in a position to know the phenomenal truths), and conclude from this that there is a corresponding gap in the world between physical and phenomenal truths, and materialism is false. Chapter 1 introduces materialism and the arguments against materialism that I respond to in this dissertation. Chapters 2 and 3 explore the phenomenal concept strategy (PCS), one promising materialist response to the epistemic arguments against materialism. The PCS admits that there is an epistemic gap between physical and phenomenal truths, but claims that it arises because of something special about our concepts of consciousness and not because of something special about consciousness itself. Chapter 4 considers what reason there is to think that there is an epistemic gap between physical and phenomenal truths in the first place. I argue that some arguments might succeed in showing that there is such an epistemic gap, but that if these arguments succeed then they end up vindicating the PCS. Chapter 5 considers more generally what is required for an epistemic gap to exist. In particular, it considers whether conceptual analysis is necessary to close an epistemic gap

    Moral Offsetting

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    Vergleich und Identität

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    Durch die Christianisierung Skandinaviens veränderte Europa vom 9. bis zum 13. Jahrhundert sein Gesicht. Der aquilo blieb nicht mehr wie in der biblischen Tradition das kalte Jenseits, sondern ergriff seinen Platz im politischen und kulturellen Gefüge der europäischen Völker. Diese Integrationsleistung brachte auf beiden Seiten, der gebenden wie der nehmenden, neue Formen der Selbst- und Fremddeutung hervor. Das Buch vergleicht die unterschiedlichen Perspektiven in der lateinischen und volkssprachlichen Geschichtsschreibung des 11. bis 13. Jahrhunderts – sowohl in der Historiographie im Reich und in England als auch und vor allem im Norden. Gerade dort entfaltete sich eine große Spannbreite zwischen den Mustern kontinentaleuropäischer Darstellung und der überaus eigenständigen Welt der Sagas. Der Vergleich wird hierbei als wesentliches Instrument der Identitätskonstruktion hervorgehoben

    Dynamics of spin and density fluctuations in strongly interacting few-body systems

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    The decoupling of spin and density dynamics is a remarkable feature of quantum one-dimensional many-body systems. In a few-body regime, however, little is known about this phenomenon. To address this problem, we study the time evolution of a small system of strongly interacting fermions after a sudden change in the trapping geometry. We show that, even at the few-body level, the excitation spectrum of this system presents separate signatures of spin and density dynamics. Moreover, we describe the effect of considering additional internal states with SU(N) symmetry, which ultimately leads to the vanishing of spin excitations in a completely balanced system.Comment: 32 pages, 6 figure

    Dynamical realization of magnetic states in a strongly interacting Bose mixture

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    We describe the dynamical preparation of magnetic states in a strongly interacting two-component Bose gas in a harmonic trap. By mapping this system to an effective spin-chain model, we obtain the dynamical spin densities and the fidelities for a few-body system. We show that the spatial profiles transit between ferromagnetic and antiferromagnetic states as the intraspecies interaction parameter is slowly increased

    Exploratory Combinatorial Optimization with Reinforcement Learning

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    Many real-world problems can be reduced to combinatorial optimization on a graph, where the subset or ordering of vertices that maximize some objective function must be found. With such tasks often NP-hard and analytically intractable, reinforcement learning (RL) has shown promise as a framework with which efficient heuristic methods to tackle these problems can be learned. Previous works construct the solution subset incrementally, adding one element at a time, however, the irreversible nature of this approach prevents the agent from revising its earlier decisions, which may be necessary given the complexity of the optimization task. We instead propose that the agent should seek to continuously improve the solution by learning to explore at test time. Our approach of exploratory combinatorial optimization (ECO-DQN) is, in principle, applicable to any combinatorial problem that can be defined on a graph. Experimentally, we show our method to produce state-of-the-art RL performance on the Maximum Cut problem. Moreover, because ECO-DQN can start from any arbitrary configuration, it can be combined with other search methods to further improve performance, which we demonstrate using a simple random search.Comment: In Proceedings of the 34th National Conference on Artificial Intelligence, AAAI 202

    The influence of fractionated radiotherapy on the stability of spinal bone metastases: a retrospective analysis from 1047 cases

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    Background: The effect of radiotherapy, in particular the application of different multi-fraction schedules in the management of unstable spinal bone metastases (SBM), is incompletely understood. This study aims to compare the radiological response regarding various dose and fractionation schedules of radiotherapy in the palliative treatment of SBM. Methods: We retrospectively assessed 1047 patients with osteolytic SBM, treated with palliative radiotherapy at our department between 2000 and 2015. Lung cancer (40.2%), breast (16.7%) and renal cancer (15.2%) were the most common solid tumors in this study. Different common multi-fraction regimen (5x4Gy, 10x3Gy, 14 × 2.5Gy and 20x2Gy) were compared with regard to radiological response and recalcification at 3 and 6 months after radiotherapy. The Taneichi score was used for classification of osteolytic SBM. Results: Median follow up was 6.3 months. The median overall survival (OS) in the short-course radiotherapy (SCR) group using less than 10 treatment fractions was 5.5 months vs. 9.5 months in the long-course radiotherapy (LCR) group using in excess of 10 fractions (log rank p < .0001). Overall survival (OS) in the SCR group after 3 and 6 months was 66.8 and 49.1%, respectively vs 80.9 and 61.5%, respectively in the LCR group. 17.6% (n = 54/306) and 31.1% (n = 89/286) of unstable SBM were classified as stable in the SCR group at 3 and 6 months post radiotherapy, respectively (p < .001 for both). In the LCR group, 24.1% (n = 28/116) and 34.2% (n = 38/111) of unstable SBM were stabilized after 3 and 6 months, respectively (p < .001 for both). Conclusions: Our study shows no significant difference in stabilization achieving recalcification rates between multi-fraction schedules (SCR vs. LCR) in the palliative management of unstable SBM. Both groups with multi-fraction regimen demonstrate a stabilizing effect following 3 and 6 months after radiotherapy
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