417 research outputs found

    Description of a quantum convolutional code

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    We describe a quantum error correction scheme aimed at protecting a flow of quantum information over long distance communication. It is largely inspired by the theory of classical convolutional codes which are used in similar circumstances in classical communication. The particular example shown here uses the stabilizer formalism, which provides an explicit encoding circuit. An associated error estimation algorithm is given explicitly and shown to provide the most likely error over any memoryless quantum channel, while its complexity grows only linearly with the number of encoded qubits.Comment: 4 pages, uses revtex4. Minor correction in the encoding and decoding circuit

    Quantum error-correcting codes and 4-dimensional arithmetic hyperbolic manifolds

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    Using 4-dimensional arithmetic hyperbolic manifolds, we construct some new homological quantum error correcting codes. They are LDPC codes with linear rate and distance nϵn^\epsilon. Their rate is evaluated via Euler characteristic arguments and their distance using Z2\mathbb{Z}_2-systolic geometry. This construction answers a queston of Z\'emor, who asked whether homological codes with such parameters could exist at all.Comment: 21 page

    Substellar companions and the formation of hot subdwarf stars

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    "Copyright 2011 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics."We give a brief review over the observational evidence for close substellar companions to hot subdwarf stars. The formation of these core helium-burning objects requires huge mass loss of their red giant progenitors. It has been suggested that besides stellar companions substellar objects in close orbits may be able to trigger this mass loss. Such objects can be easily detected around hot subdwarf stars by medium or high resolution spectroscopy with an RV accuracy at the km s(-1)-level. Eclipsing systems of Vir type stick out of transit surveys because of their characteristic light curves. The best evidence that substellar objects in close orbits around sdBs exist and that they are able to trigger the required mass loss is provided by the eclipsing system SDSS J0820+0008, which was found in the course of the MUCHFUSS project. Furthermore, several candidate systems have been discovered.Final Accepted Versio

    Aquatics reconstruction software: the design of a diagnostic tool based on computer vision algorithms

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    Computer vision methods can be applied to a variety of medical and surgical applications, and many techniques and algorithms are available that can be used to recover 3D shapes and information from images range and volume data. Complex practical applications, however, are rarely approachable with a single technique, and require detailed analysis on how they can be subdivided in subtasks that are computationally treatable and that, at the same time, allow for the appropriate level of user-interaction. In this paper we show an example of a complex application where, following criteria of efficiency, reliability and user friendliness, several computer vision techniques have been selected and customized to build a system able to support diagnosis and endovascular treatment of Abdominal Aortic Aneurysms. The system reconstructs the geometrical representation of four different structures related to the aorta (vessel lumen, thrombus, calcifications and skeleton) from CT angiography data. In this way it supports the three dimensional measurements required for a careful geometrical evaluation of the vessel, that is fundamental to decide if the treatment is necessary and to perform, in this case, its planning. The system has been realized within the European trial AQUATICS (IST-1999-20226 EUTIST-M WP 12), and it has been widely tested on clinical data

    Lived religion: Rethinking human nature in a neoliberal age

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    This article considers the relationship between philosophy of religion and an approach to the study of religion, which prioritises the experience of lived religion. Considering how individuals and communities live out their faith challenges some of the assumptions of analytic philosophers of religion regarding the position the philosopher should adopt when approaching the investigation of religion. If philosophy is understood principally as a means for analysing belief, it will have little space for an engagement with what it feels like to live out one’s faith

    Whose Science and whose Religion? Reflections on the Relations between Scientific and Religious Worldviews

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    Arguments about the relationship between science and religion often proceed by identifying a set of essential characteristics of scientific and religious worldviews and arguing on the basis of these characteristics for claims about a relationship of conflict or compatibility between them. Such a strategy is doomed to failure because science, to some extent, and religion, to a much larger extent, are cultural phenomena that are too diverse in their expressions to be characterized in terms of a unified worldview. In this paper I follow a different strategy. Having offered a loose characterization of the nature of science, I pose five questions about specific areas where religious and scientific worldviews may conflict - questions about the nature of faith, the belief in a God or Gods, the authority of sacred texts, the relationship between scientific and religious conceptions of the mind/soul, and the relationship between scientific and religious understandings of moral behavior. My review of these questions will show that they cannot be answered unequivocally because there is no agreement amongst religious believers as to the meaning of important religious concepts. Thus, whether scientific and religious worldviews conflict depends essentially upon whose science and whose religion one is considering. In closing, I consider the implications of this conundrum for science education

    Reviews of

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    Antibiotic Switch therapy is defined by the switch of intravenous antibiotic therapy to oral form. This research aimed to learn about the relationship of switch therapy toward the value of wound healing, lenght of stay and the antibiotic expenditure. The data of this cross sectional study was collected from medical record and by direct investigation to patients for their macroscopis the wound healings value. T-test was used to compared the relationship of the patient wound healings value, lenght of stay and the antibiotic expenditure between the those with and accurate switch therapy and those without it. The result showed that there was no different of wound healing value between those groups of patients (P>0,1). On the other hand, lenght of stay and antibiotic expenditure of the patient with the accurate switch therapy was cuted on the patient with the accurate switch therapy. These indicated that accuracy of switch therapy will proceed a benefit outcome to the patient with appendicitis, especially to there lenght of stay and antibiotic expenditure as well

    Classical and revisionary theism on the divine as personal: a rapprochement?

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    To claim that the divine is a person or personal is, according to Richard Swinburne, ‘the most elementary claim of theism’ (1993, 101). I argue that, whether the classical theist’s concept of the divine as a person or personal is construed as an analogy or a metaphor, or a combination of the two, analysis necessitates qualification of that concept such that any differences between the classical theist’s concept of the divine as a person or personal and revisionary interpretations of that concept are merely superficial. Thus, either the classical theist has more in common with revisionary theism than he/she might care to admit, or classical theism is a multi-faceted position which encompasses interpretations which some might regard as revisionist. This article also explores and employs the use of a gender-neutral pronoun in talk about God
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