Counterions at Charged Cylinders: Criticality and universality beyond mean-field

The counterion-condensation transition at charged cylinders is studied using Monte-Carlo simulation methods. Employing logarithmically rescaled radial coordinates, large system sizes are tractable and the critical behavior is determined by a combined finite-size and finite-ion-number analysis. Critical counterion localization exponents are introduced and found to be in accord with mean-field theory both in 2 and 3 dimensions. In 3D the heat capacity shows a universal jump at the transition, while in 2D, it consists of discrete peaks where single counterions successively condense.Comment: 4 pages, 3 figures; submitted to Phys. Rev. Lett. (2005

Capillary zone electrophoretic studies of ion association between inorganic anions and tetraalkylammonium ions in aqueous-dioxane media

Ion association between inorganic anions and symmetrical tetraalkylammonium ions, R4N+ (R = Me, Et, Pr, n-Bu, n-Am, and 2-methyl butyl {isoamyl = iAm}) was investigated using ordinary silica capillary by capillary zone electrophoresis. An improved version of the Williams-Vigh method was used for the first time to measure the mobilities of the inorganic anions. Plots of log K-ass against log dielectric constant in various media, revealed a smaller change in K-ass compared to dielectric constant. These plots suggest that the Bjerrum's equation is inadequate in accounting for the associations of ions in a CZE setup. </p

Onsager-Manning-Oosawa condensation phenomenon and the effect of salt

Making use of results pertaining to Painleve III type equations, we revisit the celebrated Onsager-Manning-Oosawa condensation phenomenon for charged stiff linear polymers, in the mean-field approximation with salt. We obtain analytically the associated critical line charge density, and show that it is severely affected by finite salt effects, whereas previous results focused on the no salt limit. In addition, we obtain explicit expressions for the condensate thickness and the electric potential. The case of asymmetric electrolytes is also briefly addressed.Comment: to appear in Phys. Rev. Let

Bisexuality And Identity Formation

This study explores the identity development and psychological adjustment of bisexual individuals (n = 138) as compared to homosexual (n = 45) and heterosexual participants (n = 558). Undergraduate students recruited from psychology classes at a large metropolitan university in Florida (67% female, 65% Caucasian) took an online survey for course extra credit. Bisexual and homosexual participants scored higher in identity exploration than the heterosexual participants. Bisexual participants scored significantly higher in psychological symptom severity than heterosexual participants. The three groups were not significantly different in identity commitment nor in identity distress. Female bisexual participants scored more similar to the homosexual participants in identity exploration, while the male bisexual participants were more similar to the heterosexual participants. Among males, bisexual and homosexual participants reported greater psychological symptom severity than heterosexual participants. There were no differences between groups for female participants in regard to symptom severity. This study highlights the need for more research into the psychological correlates of bisexuality as a distinct group from homosexuality, as well as the need to focus on gender as a significant moderator of these relationships