58,591 research outputs found
Towards Large-scale Inconsistency Measurement
We investigate the problem of inconsistency measurement on large knowledge
bases by considering stream-based inconsistency measurement, i.e., we
investigate inconsistency measures that cannot consider a knowledge base as a
whole but process it within a stream. For that, we present, first, a novel
inconsistency measure that is apt to be applied to the streaming case and,
second, stream-based approximations for the new and some existing inconsistency
measures. We conduct an extensive empirical analysis on the behavior of these
inconsistency measures on large knowledge bases, in terms of runtime, accuracy,
and scalability. We conclude that for two of these measures, the approximation
of the new inconsistency measure and an approximation of the contension
inconsistency measure, large-scale inconsistency measurement is feasible.Comment: International Workshop on Reactive Concepts in Knowledge
Representation (ReactKnow 2014), co-located with the 21st European Conference
on Artificial Intelligence (ECAI 2014). Proceedings of the International
Workshop on Reactive Concepts in Knowledge Representation (ReactKnow 2014),
pages 63-70, technical report, ISSN 1430-3701, Leipzig University, 2014.
http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-15056
Chromium vI induced cytoskeletal damage and cell death in isolated hepatocytes
Cr(VI) is a known human carcinogen. Although it has been investigated widely, the mechanism(s) of its action is/are not fully understood. The aim of this study was to evaluate Cr(VI)-induced damage to the cell cytoskeleton and the mode of cell death in primary cultures of hepatocytes. Exposure of the cultured cells (10(5)/cm(2)) to 1 and 5 microM Cr(VI) for 24 h resulted in loss of the cell cytoskeleton, and this was accompanied by membrane blebbing and shrinking of the cell. Staining of the cells with annexin V and propidium iodide showed that Cr(VI) induces apoptosis at low concentrations (5 microM), whereas at higher concentrations (25 microM) it induces necrosis. This study shows that Cr(VI) causes damage to the cell cytoskeleton, and induces apoptosis at low concentrations. However, the importance of necrosis and apoptosis in vivo, and the effects of longer exposure times, which simulate environmental and occupational exposure to Cr(VI), remain to be investigated
Spacecraft attitude sensor
A system for sensing the attitude of a spacecraft includes a pair of optical scanners having a relatively narrow field of view rotating about the spacecraft x-y plane. The spacecraft rotates about its z axis at a relatively high angular velocity while one scanner rotates at low velocity, whereby a panoramic sweep of the entire celestial sphere is derived from the scanner. In the alternative, the scanner rotates at a relatively high angular velocity about the x-y plane while the spacecraft rotates at an extremely low rate or at zero angular velocity relative to its z axis to provide a rotating horizon scan. The positions of the scanners about the x-y plane are read out to assist in a determination of attitude. While the satellite is spinning at a relatively high angular velocity, the angular positions of the bodies detected by the scanners are determined relative to the sun by providing a sun detector having a field of view different from the scanners
Diversity and profitability : evidence and future research directions / 1433
Includes bibliographical references (p. 23-24)
Do Two Temperature Debris Disks Have Multiple Belts?
We present a study of debris disks whose spectra are well modelled by dust
emission at two different temperatures. These disks are typically assumed to be
a sign of multiple belts, which in only a few cases have been confirmed via
high resolution observations. We first compile a sample of two-temperature
disks to derive their properties, summarised by the ratios of the warm and cool
component temperatures and fractional luminosities. The ratio of warm to cool
temperatures is constant in the range 2-4, and the temperatures of both warm
and cool components increases with stellar mass. We then explore whether this
emission can arise from dust in a single narrow belt, with the range of
temperatures arising from the size variation of grain temperatures. This model
can produce two-temperature spectra for Sun-like stars, but is not supported
where it can be tested by observed disk sizes and far-IR/mm spectral slopes.
Therefore, while some two-temperature disks arise from single belts, it is
probable that most have multiple spatial components. These disks are plausibly
similar to the outer Solar System's configuration of Asteroid and
Edgeworth-Kuiper belts separated by giant planets. Alternatively, the inner
component could arise from inward scattering of material from the outer belt,
again due to intervening planets. In either case, we suggest that the ratio of
warm/cool component temperatures is indicative of the scale of outer planetary
systems, which typically span a factor of about ten in radius.Comment: accepted to MNRA
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