Cosmological Implications of the Fundamental Relations of X-ray Clusters

Based on the two-parameter family nature of X-ray clusters of galaxies obtained in a separate paper, we discuss the formation history of clusters and cosmological parameters of the universe. Utilizing the spherical collapse model of cluster formation, and assuming that the cluster X-ray core radius is proportional to the virial radius at the time of the cluster collapse, the observed relations among the density, radius, and temperature of clusters imply that cluster formation occurs in a wide range of redshift. The observed relations favor the low-density universe. Moreover, we find that the model of $n\sim -1$ is preferable.Comment: 7 pages, 4 figures. To be published in ApJ Letter

Earnings management of brazilian firms in the IFRS era: The role of economic and institutional factors

This study investigates whether accounting quality – more specifically regarding the level of earnings management by accruals – is associated with a country’s economic and institutional factors that change over time in IFRS era. Based on a sample of 1,387 Brazilian firm-year observations and data regarding 2011 to 2018, econometric models are estimated considering the absolute amount of discretionary accruals as proxy for earnings management and different aspects related to economic and institutional factors of preeminent importance to an emerging economy. We show that in general, high inflation, stock market volatility, and policy uncertainty rates, as well as lower regulatory quality, on average, are associated with a higher level of earnings management in Brazil. This study contributes to the accounting literature in emerging economies discussing the role of economic and institutional factors on accounting quality in the IFRS era in one of the largest developing country in the world. Compared to developed countries or even to other developing economies, Brazil stands out as an emerging economy of considerable economic and political instability, making it a valuable setting for this analysisinfo:eu-repo/semantics/publishedVersio

Does national ethical judgment matter for earnings management?

This study analyses the effect of ethical judgment at country-level on earnings management. While previous literature document the role of ethical issues at personal- and organizational-level on earnings management practices, usually theoretically and through qualitative ways, we investigate that association in a large sample at international level taken a sample of 81,408 firm-year observations regarding 10,306 firms from 39 countries. Based on data from an international questionnaire developed by the World Values Survey, we construct a comprehensive index of ethical judgment of each country. Our empirical findings suggest that the level of ethical judgment of the countries are negative associated with accruals-based earnings management, suggesting that the manipulation of accounting amounts is lower in countries where ethically suspect behaviours are less acceptable. Additionally, we also provide empirical evidences that this phenomenon is verified both in developed and emerging countries, and that ethical judgment at country-level seem to moderate the association between IFRS adoption and earnings management practices.info:eu-repo/semantics/acceptedVersio

Hanbury Brown Twiss effect for ultracold quantum gases

We have studied 2-body correlations of atoms in an expanding cloud above and below the Bose-Einstein condensation threshold. The observed correlation function for a thermal cloud shows a bunching behavior, while the correlation is flat for a coherent sample. These quantum correlations are the atomic analogue of the Hanbury Brown Twiss effect. We observe the effect in three dimensions and study its dependence on cloud size.Comment: Figure 1 availabl

Process transparency on construction sites : examples from construction companies in Brazil

Process transparency is the core concept in Visual Management (VM), which is one of the founding blocks of the Toyota Production System. This paper presents the preliminary results of a collaborative research conducted between Brazil and the UK, as part of a research effort focused on the application of Visual Management in construction. How process transparency is realized on construction sites is the main research question of the paper. The use of this concept and the implementation of the transparency theory were investigated through multiple case studies, carried out in nine different construction companies. The findings are explained through six theoretical transparency increasing approaches. The affecting parameters in the application of, the management’s perception of and several methods in process transparency in construction were identified. Further work, especially exploring the functions of process transparency on construction sites and reflecting the worker perception of the issue, is necessary to elaborate the process transparency concept

Moderating effect of economic instability in the relationship between concentration of control and market value: empirical evidence in Latin America

This paper investigates the moderating effect of economic instability in the relationship between the concentration of control and market value of firms. For this purpose, we built an unbalanced panel dataset composed of 341 Latin American companies from six countries: Argentina, Brazil, Chile, Colombia, Mexico, and Peru. The results of the dynamic models, estimated using the systemic generalized method of moments, indicate, in general, that concentration of control only reduces the market value of firms in environments with high economic instability. Thus, this study provides empirical evidence that times of economic instability encourage controlling shareholders to act even more strongly in their own interests, which may result in the expropriation of the wealth of smaller shareholders.info:eu-repo/semantics/publishedVersio

On the quantumness of correlations in nuclear magnetic resonance

Nuclear Magnetic Resonance (NMR) was successfully employed to test several protocols and ideas in Quantum Information Science. In most of these implementations the existence of entanglement was ruled out. This fact introduced concerns and questions about the quantum nature of such bench tests. In this article we address some issues related to the non-classical aspects of NMR systems. We discuss some experiments where the quantum aspects of this system are supported by quantum correlations of separable states. Such quantumness, beyond the entanglement-separability paradigm, is revealed via a departure between the quantum and the classical versions of information theory. In this scenario, the concept of quantum discord seems to play an important role. We also present an experimental implementation of an analogous of the single-photon Mach-Zehnder interferometer employing two nuclear spins to encode the interferometric paths. This experiment illustrate how non-classical correlations of separable states may be used to simulate quantum dynamics. The results obtained are completely equivalent to the optical scenario, where entanglement (between two field modes) may be present

Ionization rates in a Bose-Einstein condensate of metastable Helium

We have studied ionizing collisions in a BEC of He*. Measurements of the ion production rate combined with measurements of the density and number of atoms for the same sample allow us to estimate both the 2 and 3-body contributions to this rate. A comparison with the decay of the number of condensed atoms in our magnetic trap, in the presence of an rf-shield, indicates that ionizing collisions are largely or wholly responsible for the loss. Quantum depletion makes a substantial correction to the 3-body rate constant.Comment: 4 pages, 3 figure

Normalizing the Temperature Function of Clusters of Galaxies

We re-examine the constraints which can be robustly obtained from the observed temperature function of X-ray cluster of galaxies. The cluster mass function has been thoroughly studied in simulations and analytically, but a direct simulation of the temperature function is presented here for the first time. Adaptive hydrodynamic simulations using the cosmological Moving Mesh Hydro code of Pen (1997a) are used to calibrate the temperature function for different popular cosmologies. Applying the new normalizations to the present-day cluster abundances, we find $\sigma_8=0.53\pm 0.05 \Omega_0^{-0.45}$ for a hyperbolic universe, and $\sigma_8=0.53\pm 0.05 \Omega_0^{-0.53}$ for a spatially flat universe with a cosmological constant. The simulations followed the gravitational shock heating of the gas and dark matter, and used a crude model for potential energy injection by supernova heating. The error bars are dominated by uncertainties in the heating/cooling models. We present fitting formulae for the mass-temperature conversions and cluster abundances based on these simulations.Comment: 20 pages incl 5 figures, final version for ApJ, corrected open universe \gamma relation, results unchange