Testing device subjects elastic materials to biaxial deformations

Testing device stretches elastic materials biaxially over large deformation ranges and varies strain ratios in two perpendicular directions. The device is used in conjunction with a tensile testing machine, which holds the specimen and permits control over the direction and magnitude of the stresses applied

An Entrepreneurial Theory of Formal Organizations. Part I - Patterns of Formal Organizations

Theory of formal organizations with ordering of relevant dat

How Far From the Euro Area? Measuring Convergence of Inflation Rates in Eastern Europe

We present a common factor framework of convergence which we implement using principal components analysis. We apply this technique to a dataset of monthly inflation rates of EMU and the Eastern European New Member Countries (NMC) over 1996-2007. In the earlier years, the NMC rates moved independently from an average of the three best performing countries over the past twelve months, while they moved somewhat closer in line with them in the later years. Looking at the sample of the EMU and NMC countries as a whole, there is evidence of a formation of convergence clubs across the two groups.Convergence; inflation rates; European Monetary Union; principal components analysis

How Far From the Euro Area? Measuring Convergence of Inflation Rates in Eastern Europe

We present a common factor framework of convergence which we implement using principal components analysis. We apply this technique to a dataset of monthly inflation rates of EMU and the Eastern European New Member Countries (NMC) over 1996-2007. In the earlier years, the NMC rates moved independently from an average of the three best performing countries over the past twelve months, while they moved somewhat closer in line with them in the later years. Looking at the sample of the EMU and NMC countries as a whole, there is evidence of a formation of convergence clubs across the two groups.Convergence, inflation rates, European Monetary Union, principal components analysis.

A New Look at Economic Convergence in Europe: A Common Factor Approach

We propose a common factor approach to analyse convergence, which we implement using principal components analysis. We show that this method provides a useful new way of approaching the convergence debate. We apply this technique to a dataset of nominal and real monthly exchange rates of the twelve member countries of the European Monetary Union over the period 1970-2001. Our empirical results neatly capture the convergence patterns related to the various regimes from Bretton Woods toward EMU. The UK's Pound Sterling has been on a gradual convergence path to the Euro, although convergence is less progressed than it was for the EMU countries by 1999.Convergence, exchange rates, European Monetary Union, nominal convergence, real convergence, principal components analysis.

Measuring Convergence of the New Member Countries’ Exchange Rates to the Euro

We propose a common factor approach to analyse convergence, which we implement using principal components analysis. This technique has not been used to analyse convergence of time series but is shown to provide a useful new tool. We show how it is in many ways a more natural way of approaching the convergence debate. We apply these ideas to a dataset of bilateral Euro and US-Dollar exchange rates of the new member countries of the European Union. Our empirical application gives sensible results about the convergence process of the new member countries’ exchange rates to the Euro.Convergence; exchange rates; transition economies; principal components analysis

Autonomous Spacecraft Navigation With Pulsars

An external reference system suitable for deep space navigation can be defined by fast spinning and strongly magnetized neutron stars, called pulsars. Their beamed periodic signals have timing stabilities comparable to atomic clocks and provide characteristic temporal signatures that can be used as natural navigation beacons, quite similar to the use of GPS satellites for navigation on Earth. By comparing pulse arrival times measured on-board a spacecraft with predicted pulse arrivals at a reference location, the spacecraft position can be determined autonomously and with high accuracy everywhere in the solar system and beyond. The unique properties of pulsars make clear already today that such a navigation system will have its application in future astronautics. In this paper we describe the basic principle of spacecraft navigation using pulsars and report on the current development status of this novel technology.Comment: 22 pages, 12 figures, 2 tables, to be published in the proceedings of the workshop "Relativistic Positioning Systems and their Scientific Applications", held on 19-21 Sept. 2012, Brdo near Kranj, Sloveni

A binary signature in the non-thermal radio-emitter Cyg OB2 #9

Aims: Non-thermal radio emission associated with massive stars is believed to arise from a wind-wind collision in a binary system. However, the evidence of binarity is still lacking in some cases, notably Cyg OB2 #9 Methods: For several years, we have been monitoring this heavily-reddened star from various observatories. This campaign allowed us to probe variations both on short and long timescales and constitutes the first in-depth study of the visible spectrum of this object. Results: Our observations provide the very first direct evidence of a companion in Cyg OB2 #9, confirming the theoretical wind-wind collision scenario. These data suggest a highly eccentric orbit with a period of a few years, compatible with the 2yr-timescale measured in the radio range. In addition, the signature of the wind-wind collision is very likely reflected in the behaviour of some emission lines.Comment: accepted by A&A, 4 p, 3figure

Pulsar Polar Cap Heating and Surface Thermal X-Ray Emission I. Curvature Radiation Pair Fronts

We investigate the effect of pulsar polar cap (PC) heating produced by positrons returning from the upper pair formation front. Our calculations are based on a self-consistent treatment of the pair dynamics and the effect of electric field screening by the returning positrons. We calculate the resultant X-ray luminosities, and discuss the dependence of the PC heating efficiencies on pulsar parameters, such as characteristic spin-down age, spin period, and surface magnetic field strength. In this study we concentrate on the regime where the pairs are produced in a magnetic field by curvature photons emitted by accelerating electrons. Our theoretical results are not in conflict with the available observational X-ray data and suggest that the effect of PC heating should significantly contribute to the thermal X-ray fluxes from middle-aged and old pulsars. The implications for current and future X-ray observations of pulsars are briefly outlined.Comment: 28 pages, 7 figures, accepted for publication in Ap

The hydrogen atom in electric and magnetic fields : Pauli's 1926 article

The results obtained by Pauli, in his 1926 article on the hydrogen atom, made essential use of the dynamical so(4) symmetry of the bound states. Pauli used this symmetry to compute the perturbed energy levels of an hydrogen atom in a uniform electric field (Stark effect) and in uniform electric and magnetic fields. Although the experimental check of the single Stark effect on the hydrogen atom has been studied experimentally, Pauli's results in mixed fields have been studied only for Rydberg states of rubidium atoms in crossedfields and lithium atoms in parallel fields.Comment: 11 pages, latex file, 2 figure