From 2-Dimensional Surfaces to Cosmological Solutions

We construct perfect fluid metrics corresponding to spacelike surfaces invariant under a 1-dimensional group of isometries in 3-dimensional Minkowski space. Under additional assumptions we obtain new cosmological solutions of Bianchi type II, VI_0 and VII_0. The solutions depend on an arbitrary function of time, which can be specified in order to satisfy an equation of state.Comment: 12 pages, no figures, LaTeX2e, to be published in Class. Quant. Gra

Coherent states for the q-deformed quantum mechanics on a circle

The q-deformed coherent states for a quantum particle on a circle are introduced and their properties investigated.Comment: 11 pages, 2 PostScript figure

Heavy Duty Vehicle Fuel Consumption Modelling Using Artificial Neural Networks.

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.In this paper an artificial neural network (ANN) approach to modelling fuel consumption of heavy duty vehicles is presented. The proposed method uses easy accessible data collected via CAN bus of the truck. As a benchmark a conventional method, which is based on polynomial regression model, is used. The fuel consumption is measured in two different tests, performed by using a unique test bench to apply the load to the engine. Firstly, a transient state test was performed, in order to evaluate the polynomial regression and 25 ANN models with different parameters. Based on the results, the best ANN model was chosen. Then, validation test was conducted using real duty cycle loads for model comparison. The neural network model outperformed the conventional method and represents fuel consumption of the engine operating in transient states significantly better. The presented method can be applied in order to reduce fuel consumption in utility vehicles delivering accurate fuel economy model of truck engines, in particular in low engine speed and torque range

Weak gravitational lensing in the standard Cold Dark Matter model, using an algorithm for three-dimensional shear

We investigate the effects of weak gravitational lensing in the standard Cold Dark Matter cosmology, using an algorithm which evaluates the shear in three dimensions. The algorithm has the advantage of variable softening for the particles, and our method allows the appropriate angular diameter distances to be applied to every evaluation location within each three-dimensional simulation box. We investigate the importance of shear in the distance-redshift relation, and find it to be very small. We also establish clearly defined values for the smoothness parameter in the relation, finding its value to be at least 0.88 at all redshifts in our simulations. From our results, obtained by linking the simulation boxes back to source redshifts of 4, we are able to observe the formation of structure in terms of the computed shear, and also note that the major contributions to the shear come from a very broad range of redshifts. We show the probability distributions for the magnification, source ellipticity and convergence, and also describe the relationships amongst these quantities for a range of source redshifts. We find a broad range of magnifications and ellipticities; for sources at a redshift of 4, 97{1/2}% of all lines of sight show magnifications up to 1.3 and ellipticities up to 0.195. There is clear evidence that the magnification is not linear in the convergence, as might be expected for weak lensing, but contains contributions from higher order terms in both the convergence and the shear.Comment: 14 pages, LaTeX, 15 figures include

The ARAUCARIA project. Discovery of Cepheid Variables in NGC 300 from a Wide-Field Imaging Survey

Based on observations of NGC 300, obtained with the Wide-Field Camera at the 2.2 m ESO/MPI telescope during 29 nights spread over a 5.3 month interval, 117 Cepheids and 12 Cepheid candidates were found which cover the period range from 115 to 5.4 days. We present a catalog which provides equatorial coordinates, period, time of maximum brightness, and intensity mean B and V magnitudes for each variable, and we show phased B and V light curves for all the Cepheids found. We also present the individual B and V observations for each Cepheid in our catalog. We find very good agreement between our photometry and that obtained by Freedman et al. from ground-based CCD data for common stars. The Cepheids delineate the spiral arms of NGC 300, and a couple of them were detected very close to the center of the galaxy. From the color-magnitude diagram of NGC 300 constructed from our data, we expect that our Cepheid detection is near-complete for variables with periods larger than about 10 days. We present plots of the PL relations in the B and V bands obtained from our data, which clearly demonstrate the presence of a Malmquist bias for periods below about 10 days. A thorough discussion of the distance to NGC 300 will be presented in a forthcoming paper which will include the analysis of photometry in longer-wavelength bands.Comment: 26 pages, Latex. Astronomical Journal in pres

Cardiac Depression Scale: Mokken scaling in heart failure patients

Background: There is a high prevalence of depression in patients with heart failure (HF) that is associated with worsening prognosis. The value of using a reliable and valid instrument to measure depression in this population is therefore essential. We validated the Cardiac Depression Scale (CDS) in heart failure patients using a model of ordinal unidimensional measurement known as Mokken scaling. Findings: We administered in face-to-face interviews the CDS to 603 patients with HF. Data were analysed using Mokken scale analysis. Items of the CDS formed a statistically significant unidimensional Mokken scale of low strength (H<0.40) and high reliability (Rho>0.8). Conclusions: The CDS has a hierarchy of items which can be interpreted in terms of the increasingly serious effects of depression occurring as a result of HF. Identifying an appropriate instrument to measure depression in patients with HF allows for early identification and better medical management. Keywords: Cardiac Depression Scale, Heart failure, Depression, Mokken scalin

The Ackermann Award 2013

Report on the Ackermann Award 2013

European Works Councils Experiences

In September, 2011 there was 15th anniversary of the implementation of the first EU directive creating European Works Councils (EWCs). This is also the year when the new version of the directive was put in force, i.e. Directive 2009/38/EC. EWCs are a form of indirect employee participation on European level which guarantees workers the right to information and consultation. The employees' representatives of all undertakings of transnational company were given the opportunity to voice their opinion about the decisions to be made by central management of the company. In this article three major topics are discussed: the role of European Works Councils in EU countries, the range of these institutions of employee participation on European level and changes in EWCs' functioning introduced by the new EWC directive. The main aim of the paper is to present diverse patterns of these institutions as well as to attempt the evaluation of EWCs effectiveness and their influence on the system of industrial relations in Europe.We wrześniu 2011 r. minęła 15 rocznica wejścia w życie pierwszej unijnej dyrektywy powołującej Europejskie Rady Zakładowe (ERZ). W tym roku także zaczęła obowiązywać nowa wersja tej regulacji, tzn. dyrektywa 2009/38/EC. ERZ są formą reprezentacyjnej partycypacji pracowniczej na poziomie europejskim, która gwarantuje pracownikom prawo do informacji i konsultacji. Reprezentanci załogi otrzymali możliwość wyrażania swoich opinii o projektowanych decyzjach centralnego kierownictwa przedsiębiorstwa transnarodowego, które odnoszą się do pracowników we wszystkich zakładach tego przedsiębiorstwa. Niniejszy artykuł koncentruje się trzech głównych obszarach: roli Europejskich Rad Zakładowych w krajach UE, zasięgu tych instytucji partycypacji na poziomie europejskim i zmianach w funkcjonowaniu ERZ spowodowanych wprowadzeniem nowej dyrektywy. Głównym celem artykułu jest przedstawienie różnych rodzajów tych instytucji oraz próba oceny efektywności ERZ i ich wpływu na system stosunków przemysłowych w Europie