Temperature-Driven Mixing-Demixing Behavior of Binary Mixtures of the Ionic Liquid Choline Bis(trifluoromethylsulfonyl)imide and Water

The ionic liquid (2-hydroxyethylammonium)trimethylammonium) bis(trifluoromethylsulfonyl)imide (choline bistriflimide) was obtained as a supercooled liquid at room temperature (melting point = 30 degrees C). Crystals of choline bistriflimide suitable for structure determination were grown from the melt in situ on the X-ray diffractometer. The choline cation adopts a folded conformation, whereas the bistriflimide anion exhibits a transoid conformation. The choline cation and the bistriflimide anion are held together by hydrogen bonds between the hydroxyl proton and a sulfonyl oxygen atom. This hydrogen bonding is of importance for the temperature-dependent solubility proper-ties of the ionic liquid. Choline bistriflimide is not miscible with water at room temperature, but forms one phase with water at temperatures above 72 degrees C (equals upper critical solution temperature). H-1 NMR studies show that the hydrogen bonds between the choline cation and the bistriflimide anion are substantially weakened above this temperature. The thermophysical properties of water-choline bistriflimide binary mixtures were furthermore studied by a photopyroelectric technique and by adiabatic scanning calorimetry (ASC). By photothermal analysis, besides highly accurate values for the thermal conductivity and effusivity of choline bistriflimide at 30 degrees C, the detailed temperature dependence of both the thermal conductivity and effusivity of the upper and lower part of a critical water-choline bistriflimide mixture in the neighborhood of the mixing-demixing phase transition could be determined with high resolution and accuracy. Together with high resolution ASC data for the heat capacity, experimental values were obtained for the critical exponents alpha and beta, and for the critical amplitude ratio G(+)/G(-). These three values were found to be consistent with theoretical expectations for a three dimensional Ising-type of critical behavior of binary liquid mixtures.

Same sex attraction, homophobic bullying and mental health of young people in Northern Ireland

This article reports on the relationship between same-sex attraction, experience of bullying in school and mental health measured using the 12-item version of the General Health Questionnaire (GHQ12). A random sample of 16 year olds, drawn from the Child Benefit Register, was invited to take part in the 2005 Young Life and Times survey, which is a postal survey carried out in Northern Ireland every year. Eight hundred and nineteen 16 year olds responded, which represented a return rate of 40%. The results of the survey showed that respondents who said they had been attracted to a person of the same sex at least once were significantly more likely to report experiences of school bullying. Same-sex-attracted 16 year olds were significantly less likely than those attracted to persons of the opposite sex only to say that their school provided real help to those who are being bullied. The 2005 Young Life and Times data also indicated that same-sex-attracted respondents were more than twice as likely as respondents who were only attracted to people of the opposite sex to have higher levels of psychiatric disorder. (Contains 5 tables.)

Sex differences in responsiveness to begging in a cooperative mammal

In species where young are provisioned by both parents, males commonly contribute less to parental care than females, and are less responsive to variation in begging rates. Similar differences in the care of young occur among adults in cooperative breeders, but fewer studies have investigated whether these are associated with differences in responsiveness. Here, we present results from a playback experiment investigating responsiveness to begging in the meerkat (Suricata suricatta), a cooperatively breeding mammal. Although increased begging rate raised the feeding rate of adults of both sexes, there was no consistent tendency for females to be more responsive than males. However, when we examined changes in the proportion of food items found that were fed to pups (generosity), we found that females were more responsive than males to increased begging rate. These results can be explained in terms of sex differences in dispersal: in meerkats, females are philopatric and receive considerable benefits from investing in young, both directly, by increasing group size, and indirectly, by recruiting helpers if they inherit the breeding position. In addition, they emphasize that generosity provides a more sensitive measure of responsiveness to begging than feeding rate, as it accounts for variation in foraging success. © 2008 The Royal Society.

A survey of sidedness in Northern Irish schoolchildren: The interaction of sex, age, and task

The study examined lateral preference in use of hands, feet, eyes, and ears in a group of nearly 5000 schoolchildren in Northern Ireland. Performance tests were carried out by student teachers during their school-based work in 2002 and data were submitted on-line. Six tasks were used-writing, throwing a ball, kicking a ball, hopping, listening to quiet sounds, and looking through a cardboard tube. There was right bias in every task but the extent of it differed between tasks. Males were generally less right biased than females, and younger children less than older ones; for hearing, the changes with age were markedly different in the two sexes, with females showing a strong increase in right bias but males showing none. These observational results do little to illuminate the reasons for the patterns observed.

Age and sex-related differences in automaticity for mental addition

With age, children process information more rapidly, thus increasing access to and retrieval of information from memory. This speed of information processing is often explained in terms of automaticity. The present study explores this suggestion with respect to primary schoolchildren; 173 pupils aged between 7 and 11 years were tested using a chronometric paradigm. Analysis indicated a highly significant maturational trend towards greater automaticity across all age-groups. However, the results failed to provide evidence for sex differences in automaticity, nor was there evidence of an interaction between age and sex.