Effective Transport Equations for non-Abelian Plasmas

Starting from classical transport theory, we derive a set of covariant equations describing the dynamics of mean fields and their statistical fluctuations in a non-Abelian plasma in or out of equilibrium. A general procedure is detailed for integrating-out the fluctuations as to obtain the effective transport equations for the mean fields. In this manner, collision integrals for Boltzmann equations are obtained as correlators of fluctuations. The formalism is applied to a hot non-Abelian plasma close to equilibrium. We integrate-out explicitly the fluctuations with typical momenta of the Debye mass, and obtain the collision integral in a leading logarithmic approximation. We also identify a source for stochastic noise. The resulting dynamical equations are of the Boltzmann-Langevin type. While our approach is based on classical physics, we also give the necessary generalizations to study the quantum plasmas. Ultimately, the dynamical equations for soft and ultra-soft fields change only in the value for the Debye mass.Comment: 37 pages, revtex, no figures, section VII G modified, typos remove

Structural Convergence of the Central and Eastern European Countries: Achivements in the Last Decade

The paper studies the structural convergence of the Central and Eastern European countries (CEECs) with the Euro area, in order to determine whether the last decade led an increase or a decrease of the gaps between these two regions. The main findings of the paper indicate that only three CEECs out of ten reached a higher level of structural convergence with the Euro area in the last decade, namely Latvia, Bulgaria and Slovenia. Romania remains by far the country with the highest level of structural divergence. The analysis is based on cluster methodology and the structural divergence index developed by Krugman (2001).structural convergence, Central and Eastern Europe, Euro area, clusters

Deriving effective transport equations for non-Abelian plasmas

Within classical transport theory, an approach is presented to derive systematically effective collision terms and noise sources for effective kinetic equations of non-Abelian plasmas. This procedure amounts to the `integrating-out' of fluctuations, and is applicable for in- and out-of-equilibrium situations. When applied to a hot non-Abelian plasma close to equilibrium we recover the collision integral and the noise source first obtained by B\"odeker. It is also shown that our approach, and hence B\"odeker's effective theory, is consistent with the fluctuation-dissipation theorem.Comment: 7 pages, needs sprocl.sty, invited talk given by DFL at 5th workshop on QCD (QCD2000), Villefranche-sur-Mer, France, 3-7 Jan 200

Photon Self-Energy in a Color Superconductor

In a color superconductor the diquark condensates break spontaneously both the color and ordinary electromagnetism, leaving a remanining rotated U(1) symmetry unbroken. The gauge interactions associated to this rotated symmetry may be considered as the in-medium electromagnetism. We compute the in-medium photon self-energy in the presence of diquark condensates at high baryonic density and weak coupling. This is done to one-loop order for the cases of two and three quark flavors. For vanishing temperature, a detailed discussion is given of the low momentum behavior of the photon polarization tensor. A simple physical picture for the propagation of light in color superconducting media is obtained. The main new effect is due to the diquark condensates, which lead to a strong dielectric constant of the medium. The magnetic permeability remains unchanged, because the primary condensates have vanishing spin and angular momentum. In the two flavor case, an additional contribution arises due to gapless quarks and electrons, which is responsible for Debye screening effects. We also discuss the low energy effective theory for the three flavor case in the presence of electromagnetic interactions.Comment: 26 pages, 4 postscript figures, appendix added, to appear in PR

Does economic convergence with the European Union mean more FDI flows to an economy? Analysis on 5 Central and Eastern Europe countries

In this paper we analyze the relationship between economic convergence with the European Union (EU) and foreign direct investment flows to 5 EU countries (Bulgaria, Czech Republic, Poland, Romania and Hungary) in the period 2001 – 2010, in order to determine if the process of economic convergence with the EU level influences FDI inflows in these economies. We use an economic convergence index, made up of real and structural convergence indexes, to assess the level of economic convergence. The study does not provide us with a clear response to our question. We report a tight relationship between convergence index and FDI inflows in Bulgaria, but quite divergent evolutions of the two variables in the case of Hungary.convergence index; foreign direct investments; European Union

Eyes on Romania: what to look when investing here?

In this paper we identify a framework of the main macroeconomic indicators an investor must look when investing in a country, depending on his activity business sector. Using a qualitative method of research on the Romanian case in period of 2000-2010, we establish that a series of leading indicators, as Gross Domestic Product (GDP) growth rate, inflation rate and industrial production, are appropriate to get a brief snapshot of the economic outlook of a country. The following period, since 2011 to 2014, confirm our results. Beside the traditional indicators, we set as significant the degree of business cycles synchronization with the European Union (EU) in order to predict the next path of the Romanian economy. We use a structural divergence index for assessing the similarity of economic structure between Romania and EU. The results of this study confirm that Romania lags behind EU, offering the possibility to decide the next step of an investor’s business strategy.foreign direct investment; leading indicators; business cycles synchronization

Does market concentration of downstream buyers squeeze upstream suppliers’ market power?

Using a theoretical model, we examine both the relationship between a downstream dominant firm’s market share and an upstream monopoly’s Lerner index and the relationship between upstream and downstream price elasticities of demand, in a regulated industry context. We undertake an empirical study that confirms our theoretical predictions, namely that the market share of a leader downstream firm is significant in explaining the upstream producers’ Lerner indexes. Also in accordance with the results of the theoretical model, the Lerner index is negatively influenced by the competition that suppliers face and by the level of economies of density, amongst other variables.vertical relations, buyers’ market power

Laggards or performers? CEE vs. PIIGS countries’ catch-up with the Euro area in the last ten years

This research paper develops a comparative analysis between the new members states of the European Union (EU) – from Central and Eastern Europe (CEE) – and PIIGS countries (Portugal, Italy, Ireland, Greece and Spain) in terms of economic convergence with the Euro area, in the last decade. In addition, the paper emphasizes the changes in the economic convergence levels determined by the recent international crisis. In order to assess these evolutions, we compute an aggregated index of economic convergence, made up of real and structural convergence indexes. Then, by using cluster methodology, we highlight the similarities between the states in the two groups, CEE and PIIGS, from the economic convergence perspective. The comparative analysis reveals that in 2010 only Estonia, Hungary and Slovenia report resembling characteristics to PIIGS group. We also report an important progress of the countries analyzed, as regards real and structural convergence with the Euro area. However, after a decade of catching-up, Romania remains by far the most distanced country from the Euro area.real convergence, structural convergence, Central and Eastern Europe, PIIGS, clusterization

Family and parenting characteristics associated with marijuana use by Chilean adolescents

OBJECTIVE: Family involvement and several characteristics of parenting have been suggested to be protective factors for adolescent substance use. Some parenting behaviors may have stronger relationships with adolescent behavior while others may have associations with undesirable behavior among youth. Although it is generally acknowledged that families play an important role in the lives of Chilean adolescents, scant research exists on how different family and parenting factors may be associated with marijuana use and related problems in this population which has one of the highest rates of drug use in Latin America. METHODS: Using logistic regression and negative binomial regression, we examined whether a large number of family and parenting variables were associated with the possibility of Chilean adolescents ever using marijuana, and with marijuana-related problems. Analyses controlled for a number of demographic and peer-related variables. RESULTS: Controlling for other parenting and family variables, adolescent reports of parental marijuana use showed a significant and positive association with adolescent marijuana use. The multivariate models also revealed that harsh parenting by fathers was the only family variable associated with the number of marijuana-related problems youth experienced. CONCLUSION: Of all the family and parenting variables studied, perceptions of parental use of marijuana and harsh parenting by fathers were predictors for marijuana use, and the experience of marijuana-related problems. Prevention interventions need to continue emphasizing the critical socializing role that parental behavior plays in their children's development and potential use of marijuana.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3109755/https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3109755/Accepted manuscrip