Adsorption of mono- and multivalent cat- and anions on DNA molecules

Adsorption of monovalent and multivalent cat- and anions on a deoxyribose nucleic acid (DNA) molecule from a salt solution is investigated by computer simulation. The ions are modelled as charged hard spheres, the DNA molecule as a point charge pattern following the double-helical phosphate strands. The geometrical shape of the DNA molecules is modelled on different levels ranging from a simple cylindrical shape to structured models which include the major and minor grooves between the phosphate strands. The densities of the ions adsorbed on the phosphate strands, in the major and in the minor grooves are calculated. First, we find that the adsorption pattern on the DNA surface depends strongly on its geometrical shape: counterions adsorb preferentially along the phosphate strands for a cylindrical model shape, but in the minor groove for a geometrically structured model. Second, we find that an addition of monovalent salt ions results in an increase of the charge density in the minor groove while the total charge density of ions adsorbed in the major groove stays unchanged. The adsorbed ion densities are highly structured along the minor groove while they are almost smeared along the major groove. Furthermore, for a fixed amount of added salt, the major groove cationic charge is independent on the counterion valency. For increasing salt concentration the major groove is neutralized while the total charge adsorbed in the minor groove is constant. DNA overcharging is detected for multivalent salt. Simulations for a larger ion radii, which mimic the effect of the ion hydration, indicate an increased adsorbtion of cations in the major groove.Comment: 34 pages with 14 figure

Formation of dense partonic matter in relativistic nucleus-nucleus collisions at RHIC: Experimental evaluation by the PHENIX collaboration

Extensive experimental data from high-energy nucleus-nucleus collisions were recorded using the PHENIX detector at the Relativistic Heavy Ion Collider (RHIC). The comprehensive set of measurements from the first three years of RHIC operation includes charged particle multiplicities, transverse energy, yield ratios and spectra of identified hadrons in a wide range of transverse momenta (p_T), elliptic flow, two-particle correlations, non-statistical fluctuations, and suppression of particle production at high p_T. The results are examined with an emphasis on implications for the formation of a new state of dense matter. We find that the state of matter created at RHIC cannot be described in terms of ordinary color neutral hadrons.Comment: 510 authors, 127 pages text, 56 figures, 1 tables, LaTeX. Submitted to Nuclear Physics A as a regular article; v3 has minor changes in response to referee comments. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

Customer emotions in service failure and recovery encounters

Emotions play a significant role in the workplace, and considerable attention has been given to the study of employee emotions. Customers also play a central function in organizations, but much less is known about customer emotions. This chapter reviews the growing literature on customer emotions in employee–customer interfaces with a focus on service failure and recovery encounters, where emotions are heightened. It highlights emerging themes and key findings, addresses the measurement, modeling, and management of customer emotions, and identifies future research streams. Attention is given to emotional contagion, relationships between affective and cognitive processes, customer anger, customer rage, and individual differences

Avaliação do impacto da suplementação alimentar a gestantes no cotrole do baixo peso ao nascer no município de São Paulo, SP (Brasil)

A partir de estudo realizado em oito grandes maternidades do Município de São Paulo, SP (Brasil) que atendem clientela predominantemente de baixo nível sócio-econômico, objetivou-se analisar o impacto da suplementação alimentar durante a assistência pré-natal sobre a incidência de recém-nascidos de baixo peso ao nascer (peso < 2.500 g). Foram envolvidos no estudo 1.060 recém-nascidos de mães que receberam suplementação e 664 recém-nascidos de mães que não a receberam. Ã incidência de baixo peso ao nascer foi de cerca de 11%, considerada elevada e semelhante em ambos os grupos de recém-nascidos. A análise multivariada, realizada para controlar eventuais diferenças entre os grupos, que não a condição de suplementação, descartou qualquer associação significativa entre suplementação e peso ao nascer e revelou, por outro lado, que tabagismo e morbidade na gestação e determinadas características antropométricas e reprodutivas da mãe, prévias à gestação, são importantes fatores de risco para o baixo peso ao nascer. A aparente explicação para a ausência de impacto da suplementação alimentar na população estudada parece residir não na quantidade insuficiente da suplementação alimentar oferecida (370 Kcal/dia), mas no predomínio de fatores não alimentares na determinação do baixo peso ao nascer. São formuladas recomendações quanto ao controle do baixo peso ao nascer no contexto estudado

The Nexus between Immigration, Integration and Citizenship in the EU

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