Private Management in Romanian State Owned Companies from Transportation Field

The purpose of this paper is to reveal the results of the attempt to recruit and to set up private managers in Romanian state owned companies. The study aims to highlight the problems that arose soon after the implementation of this project. Far from being a panacea solution for all these companies, from the very beginning this initiative faced a number of difficulties.  The research is realized on the Romanian transport sector revealing the major strengths and weaknesses, but also the opportunities and threats that should be considered in the attempt to solve the financial problems of state owned companies

ENVIRONMENTAL IMPACT OF ELECTRICITY

Electricity is justly considered today as an indispensable factor of existence and development of society. Besides its incontestable benefits, there can be revealed some forms of environmental impact that, to a greater or lesser extent, create concern amongst specialists, as well as among the general public. The paper proposes an analysis of the impact on the environment of the electricity, starting from the different forms of production of electric energy, presenting also the negative environmental effects of transport, distribution, and use of electricity

(In)flexibility in Power Markets with Supply from Variable Renewable Sources

With the deployment of variable renewable sources such as wind or solar photovoltaic power, electricity markets face increasing inflexibility constraints, or, in other words, increasing difficulties to swiftly adjust demand or supply in order to keep the grid in balance. The present thesis studies the impact that variable renewable energy sources have on power prices, showing that in a world with more variable renewables the flexibility needs of power markets increase

The dependence of quantile power prices on supply from renewables

Understanding power prices dynamics is crucial for valuing flexibility assets such as storage or flexible consumption facilities that accommodate fluctuations in power supply from variable renewables. Owners of such assets need to know how extreme power prices can become in order to optimally manage (dis)charging or adjusting consumption volumes. We examine how to predict those high and low prices, being the different quantiles of the power price probability distribution function, and question how supply from variable renewable sources affect different quantile prices. The first contribution of our paper is that we apply quantile regressions in a panel data framework. This methodology acknowledges that day-ahead power markets’ data is structured as cross-sectional data and, as opposed to previous quantile regression techniques introduced in power markets, allows for simultaneous predictions for all hours during a delivery day. Day-ahead power prices for all 24 h in the next day are determined at the same moment, one day before delivery. The hourly data is therefore not a time-series, but a cross section. The second contribution is that we examine the interaction between demand and supply from variable renewable sources, instead of linear dependencies only. We find that lower and higher quantile prices are more heavily affected by variations in supply from variable renewable sources than centre quantile prices. This enables owners of flexibility assets to better manage their assets in anticipation of excess or scarce supply from renewable sources. By doing so, they increase the flexibility of power systems that face increasing installed capacity of variable renewable energy sources

Molecular cloning, differential expression and 3D structural analysis of the MHC class-II β chain from sea bass (Dicentrarchus labrax L.)

The major histocompatibility complex class I and II molecules (MHC-I and MHC-II) play a pivotal role in vertebrate immune response to antigenic peptides. In this paper we report the cloning and sequencing of the MHC class II b chain from sea bass (Dicentrarchus labrax L.). The six obtained cDNA sequences (designated as Dila-DAB) code for 250 amino acids, with a predicted 21 amino acid signal peptide and contain a 28 bp 50-UTR and a 478 bp 30-UTR. A multiple alignment of the predicted translation of the Dila-DAB sequences was assembled together with other fish and mammalian sequences and it showed the conservation of most amino acid residues characteristic of the MHC class II b chain structure. The highest basal Dila-DAB expression was found in gills, followed by gut and thymus, lower mRNA levels were found in spleen, peripheral blood leucocytes (PBL) and liver. Stimulation of head kidney leukocytes with LPS for 4 h showed very little difference in the Dila-DAB expression, but after 24 h the Dila-DAB level decreased to a large extent and the difference was statistically significant. Stimulation of head kidney leukocytes with different concentrations of rIL-1b (ranging from 0 to 100 ng/ml) resulted in a dose-dependent reduction of the Dila-DAB expression. Moreover, two 3D Dila-DAB*0101 homology models were obtained based on crystallographic mouse MHC-II structures complexed with D10 T-cell antigen receptor or human CD4; features and differences between the models were evaluated and discussed. Taken together these results are of interest as MHC-II structure and function, molecular polymorphism and differential gene expression are in correlation with disease resistance to virus and bacteria in teleost fish.L'articolo è disponibile sul sito dell'editore http://www.sciencedirect.com/This work was supported by the European Commission within the project IMAQUANIM (EC contract number FOOD-CT-2005-007103)

The influence of surface morphology and wettability on the inflammatory response against poly(L-lactic acid): A semi-quantitative study with monoclonal antibodies

In this study, the influence of surface morphology and wettability of both degradable and nondegradable polymer films on the inflammatory response after subcutaneous implantation in the rat was investigated. Degradable nonporous, porous, and combi (porous with a nonporous layer on one side) poly(L-lactic acid) (PLLA) films and nondegradable polytetrafluoroethylene (PTFE) and (porous) expanded PTFE (e-PTFE) were used. Contact angles measurements indicate that PLLA is more hydrophillic than PTFE. Assessment of the inflammatory response was performed after various periods of implantation (up till 180 days), with both conventional light microscopy and immunohistochemistry using monoclonal antibodies (mAbs). The inflammatory response observed initially can largely be considered as part of the wound healing reaction, and up till day 40 the inflammatory response against PLLA was minimally more intense than against PTFE (porous as well as nonporous). From day 40 on, the PLLA films provoke a more intense inflammatory response as compared to the PTFE films. Both porous PLLA and the porous side of the combi PLLA film provoke a more intense inflammatory response than nonporous PLLA and the nonporous side of the combi PLLA film, respectively. In general, PTFE and e-PTFE films provoke an inflammatory response which is minimally more intense than the one provoked by the sham operation. Almost no ingrowth of tissue was observed in the porous e-PTFE films. In contrast, there was abundant tissue ingrowth in and an inflammatory response against porous PLLA. It can be concluded that biodegradable PLLA films provoke a more intense inflammatory response than nondegradable PTFE films. Also, porosity enhances the inflammatory response. However, porosity enhances the inflammatory response only when the wettability of a biomaterial permits cellular ingrowth

Expression and Temperature-Dependent Regulation of the Beta2-Microglobulin (Cyca-B2m) Gene in a Cold-Blooded Vertebrate, the Common Carp (Cyprinus carpio L.)

Expression of beta2-microglobulin (β 2m) in the common carp was studied using a polyclonal antibody raised against a recombinant protein obtained from eukaryotic expression of the Cyca-B2m gene. β 2m is expressed on peripheral blood Ig+ and Ig- lymphocytes, but not on erythrocytes and thrombocytes. In spleen and pronephros, dull- and bright-positive populations could be identified correlating with the presence of erythrocytes, thrombocytes, and mature leucocytes or immature and mature cells from the lympho-myeloid lineage, respectively. Thymocytes were shown to be comprised of a single bright-positive population. The Cyca-B2m polyclonal antiserum was used in conjunction with a similarly produced polyclonal antiserum to an MHC class I (Cyca-UA) α chain to investigate the expression of class I molecules on peripheral blood leucocytes (PBL) at different permissive temperatures. At 12℃, a temporary downregulation of class I molecules was demonstrated, which recovered to normal levels within 3 days. However, at 6℃, a lasting absence of class I cell-surface expression was observed, which could be restored slowly by transfer to 12C. The expression of immunoglobulin molecules on B cells was unaffected by temperature changes. The absence of the class cell-surface expression was shown to be the result of a lack of sufficient Cyca-B2m gene transcription, although Cyca-UA mRNA was present at comparable levels at all temperatures. This suggests that class I expression is regulated by a temperature-sensitive transcription of the Cyca-B2m gene

NUMERICAL EVALUATION OF SELF AND MUTUAL EARTH RETURN IMPEDANCES

The paper presents an evaluation of analytical self and mutual impedances formulas of lines with earth return, taking into account the ground correction terms. The determined formulas contain semi-infinite integral terms which are calculated by a novel stable and efficient numerical integration scheme in order to overcome the involved oscillation problems. It might seek approximations of the semi-infinite integrals by replacing an exponential or algebraic function, the objective being to permit analytic integration. Since there is no good systematic method for making these replacements, their success depends directly on the intuition and ingenuity, taking into account that in practice the integrand has limited accuracy