78,276 research outputs found
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
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
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)
An advanced OBP-based payload operating in an asynchronous network for future data relay satellites utilising CCSDS-standard data structures
A possible Data Relay Satellite System (DRSS) topology and network architecture is introduced. An asynchronous network concept, whereby each link (Inter-orbit, Inter-satellite, Feeder) is allowed to operate on its own clock, without causing loss of information, in conjunction with packet data structures, such as those specified by the CCSDS for advanced orbiting systems is discussed. A matching OBP payload architecture is described, highlighting the advantages provided by the OBP-based concept and then giving some indications on the OBP mass/power requirements
Dynamic Riemannian Geometry of the Ising Model
A general understanding of optimal control in non-equilibrium systems would
illuminate the operational principles of biological and artificial nanoscale
machines. Recent work has shown that a system driven out of equilibrium by a
linear response protocol is endowed with a Riemannian metric related to
generalized susceptibilities, and that geodesics on this manifold are the
non-equilibrium control protocols with the lowest achievable dissipation. While
this elegant mathematical framework has inspired numerous studies of exactly
solvable systems, no description of the thermodynamic geometry yet exists when
the metric cannot be derived analytically. Herein, we numerically construct the
dynamic metric of the 2D Ising model in order to study optimal protocols for
reversing the net magnetization.Comment: 5 pages, 3 figure
A Simple Model of Housing Rental and Ownership with Policy Simulations
The housing market is both large and complex. This paper develops a simple model that captures the essential features of the supply and demand for housing, and which is used to evaluate the impact of a range of policy interventions. Increases in the stock of housing would reduce rents and house prices. A reduction in tax concessions for landlords would raise rents and moderate house prices. Additional subsidies for owner-occupancy would tend to reduce rents and raise house prices. Significant reductions in rents and house prices would follow a fall in the cost of housing, through, for example lower regulatory and consent costs. Falling real interest rates result in lower rents, higher house prices and lower owner-occupancy rates. Despite the widespread attention owner-occupancy rates have attracted, the paper concludes that they are not a particularly helpful guide to the state of the housing market. Typically they are quite insensitive to policy interventions, a result that follows from the integrated view of both the rental and ownership market, adopted in this study.Housing markets; New Zealand; rental and owner-occupancy; elasticities; rents; house prices; policy simulations
Resource Price Turbulence and Macroeconomic Adjustment for a Resource Exporter: a conceptual framework for policy analysis
Increased global demand for energy and other resources, particularly from the rapidly developing economies of China and India and the opening up of global resource markets to global investors and speculative activity, has resulted in considerable recent turbulence in resource prices. The recent magnitude of change in resource prices, both positive and negative, and their macroeconomic implications is of considerable contemporary importance to both resource importing and exporting economies. For a resource exporting economy, such as that of Australia, the recent resource price boom has resulted in: increased government taxation revenue, increased employment and wages in the resource and resource related sectors, increased spending in the domestic economy that contributed to buoyant economic growth, increased resource exports to the booming economies of China and India and contributed to a stronger domestic currency with beneficial effects upon inflation. On the other hand these developments have had adverse effects on the non resource sector by: subjecting it to more intense competition for limited resources, contributing to a loss of international competitiveness and reduced exports arising from a stronger exchange rate, reducing employment in the relatively more labour intensive non resource sector, and contributing to an eventual slow down in the overall economy. These positive and negative effects, and the overall impact of a resource price boom, require a fundamentally closer analysis of the structure of the economy under scrutiny. In this context the policy response by government is likely to be pivotal in determining the overall macroeconomic outcomes from a resource price boom. The aim of this paper is to develop a generic analytical framework to appraise economic outcomes in the wake of a resource price boom for a resource producing and exporting economy. To this end a dynamic long run macroeconomic model is developed, emphasising the important role and contribution of government fiscal policy in influencing subsequent macroeconomic outcomes. The adjustment process in the model arising from a resource price shock emphasises a spending (or wealth) effect, an income effect, a revenue effect, a current account effect and an exchange rate effect, which facilitate a robust analysis of subsequent macroeconomic outcomes from such a shock as well as related policy responses.Resource price shock, dynamic macroeconomic model, simulation analysis, macroeconomic adjustment, policy analysis
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