Coupling between pressure and temperature waves in liquid helium

Pressure and temperature wave coupling in liquid helium model with thermal expansio

On the existence of quantum representations for two dichotomic measurements

Under which conditions do outcome probabilities of measurements possess a quantum-mechanical model? This kind of problem is solved here for the case of two dichotomic von Neumann measurements which can be applied repeatedly to a quantum system with trivial dynamics. The solution uses methods from the theory of operator algebras and the theory of moment problems. The ensuing conditions reveal surprisingly simple relations between certain quantum-mechanical probabilities. It also shown that generally, none of these relations holds in general probabilistic models. This result might facilitate further experimental discrimination between quantum mechanics and other general probabilistic theories.Comment: 16+7 pages, presentation improved and minor errors correcte

Integration of perception and reasoning in fast neural modules

Artificial neural systems promise to integrate symbolic and sub-symbolic processing to achieve real time control of physical systems. Two potential alternatives exist. In one, neural nets can be used to front-end expert systems. The expert systems, in turn, are developed with varying degrees of parallelism, including their implementation in neural nets. In the other, rule-based reasoning and sensor data can be integrated within a single hybrid neural system. The hybrid system reacts as a unit to provide decisions (problem solutions) based on the simultaneous evaluation of data and rules. Discussed here is a model hybrid system based on the fuzzy cognitive map (FCM). The operation of the model is illustrated with the control of a hypothetical satellite that intelligently alters its attitude in space in response to an intersecting micrometeorite shower

The active control of wing rotation by Drosophila

This paper investigates the temporal control of a fast wing rotation in flies, the ventral flip, which occurs during the transition from downstroke to upstroke. Tethered flying Drosophila actively modulate the timing of these rapid supinations during yaw responses evoked by an oscillating visual stimulus. The time difference between the two wings is controlled such that the wing on the outside of a fictive turn rotates in advance of its contralateral partner. This modulation of ventral-flip timing between the two wings is strongly coupled with changes in wing-stroke amplitude. Typically, an increase in the stroke amplitude of one wing is correlated with an advance in the timing of the ventral flip of the same wing. However, flies do display a limited ability to control these two behaviors independently, as shown by flight records in which the correlation between ventral-flip timing and stroke amplitude transiently reverses. The control of ventral-flip timing may be part of an unsteady aerodynamic mechanism that enables the fly to alter the magnitude and direction of flight forces during turning maneuvers

Exports, Services and Value Added - A National, International and Regional Analysis for Austria

Austrian business cycles are strongly dependent on the development of foreign exports. The paper deals with two important issues in this context: What is the impact of foreign exports on total growth in the Austrian economy? A more and more globalized economy implies that the share of foreign imports in the production of export commodities increases. This suggests that the contribution of foreign exports to domestic growth will diminish over time ? this hypothesis will be tested in the paper. In addition, the results for Austria will be compared with those for other countries in the EU as well as the OECD. Export activities are not evenly distributed over space: While some regions are more specialized in the production of commodities for the domestic market, other regions are much more dependent on foreign exports. In the paper, the regional economic consequences of the value-added impacts of foreign exports will be analysed. The paper will make use of national input-output tables for the years 1995, 2000 and 2003 as well as input-output tables for OECD countries to examine the national economic impacts of foreign exports and an international comparison. Furthermore, a multiregional model for Austria ("MultiREG") will be applied for estimating the corresponding regional impacts.Competitiveness, Export of Services