Ab initio molecular dynamics calculations of ion hydration free energies

We apply ab initio molecular dynamics (AIMD) methods in conjunction with the thermodynamic integration or "lambda-path" technique to compute the intrinsic hydration free energies of Li+, Cl-, and Ag+ ions. Using the Perdew-Burke-Ernzerhof functional, adapting methods developed for classical force field applications, and with consistent assumptions about surface potential (phi) contributions, we obtain absolute AIMD hydration free energies (Delta G(hyd)) within a few kcal/mol, or better than 4%, of Tissandier 's [J. Phys. Chem. A 102, 7787 (1998)] experimental values augmented with the SPC/E water model phi predictions. The sums of Li+/Cl- and Ag+/Cl- AIMD Delta G(hyd), which are not affected by surface potentials, are within 2.6% and 1.2 % of experimental values, respectively. We also report the free energy changes associated with the transition metal ion redox reaction Ag++Ni+-> Ag+Ni2+ in water. The predictions for this reaction suggest that existing estimates of Delta G(hyd) for unstable radiolysis intermediates such as Ni+ may need to be extensively revised.Comment: 18 pages, 8 figures. This version is essentially the one published in J. Chem. Phy

Ex-nihilo II: Examination Syllabi and the Sequencing of Cosmology Education

Cosmology education has become an integral part of modern physics courses. Directed by National Curricula, major UK examination boards have developed syllabi that contain explicit statements about the model of the Big Bang and the strong observational evidence that supports it. This work examines the similarities and differences in these specifications, addresses when cosmology could be taught within a physics course, what should be included in this teaching and in what sequence it should be taught at different levels.Comment: 9 pages. Accepted for publication in a special issue of Physics Educatio

Properties of metastable alkaline-earth-metal atoms calculated using an accurate effective core potential

The first three electronically excited states in the alkaline-earth-metal atoms magnesium, calcium, and strontium comprise the (nsnp) triplet P^o_J (J=0,1,2) fine-structure manifold. All three states are metastable and are of interest for optical atomic clocks as well as for cold-collision physics. An efficient technique--based on a physically motivated potential that models the presence of the ionic core--is employed to solve the Schroedinger equation for the two-electron valence shell. In this way, radiative lifetimes, laser-induced clock shifts, and long-range interaction parameters are calculated for metastable Mg, Ca, and Sr.Comment: 13 pages, 9 table

Changes in HPV prevalence following a national bivalent HPV vaccination programme in Scotland: a 7-year cross-sectional study

Background: On Sept 1, 2008, Scotland launched routine vaccination for human papillomavirus (HPV) types 16 and 18, targeted at 12–13-year-old girls, of whom 92·4% were fully vaccinated in 2008–09. In this study, we report on vaccine effectiveness of the bivalent vaccine in these vaccinated women who attended for routine cervical screening at age 20–21 years. Methods: In this 7-year cross-sectional study (covering birth cohorts 1988–1995), we sampled approximately 1000 samples per year from those attending cervical screening at age 20–21 years and tested each for HPV. By linkage to vaccination records we ascertained prevalence by birth cohort and vaccination status. Estimates of vaccine effectiveness for HPV types 16 and 18, HPV types 31, 33, and 45, other high-risk types, and any HPV were calculated using logistic regression. Findings: In total, 8584 samples were HPV genotyped. Prevalence of HPV types 16 and 18 reduced substantially from 30·0% (95% CI 26·9–33·1) in the 1988 cohort to 4·5% (3·5–5·7) in the 1995 cohort, giving a vaccine effectiveness of 89·1% (85·1–92·3) for those vaccinated at age 12–13 years. All cross-protective types showed significant vaccine effectiveness (HPV type 31, 93·8% [95% CI 83·8–98·5]; HPV type 33, 79·1% [64·2–89·0]; HPV type 45, 82·6% [61·5–93·9]). Unvaccinated individuals born in 1995 had a reduced odds of HPV types 16 and 18 infection compared with those born in 1988 (adjusted odds ratio 0·13 [95% CI 0·06–0·28]) and reduced odds of HPV types 31, 33, and 45 (odds ratio 0·45 [0·23–0·89]). Interpretation: Bivalent vaccination has led to a startling reduction in vaccine and cross-protective HPV types 7 years after vaccination. There is also evidence of herd protection against the vaccine-specific and cross-protective types in unvaccinated individuals born in 1995. These findings should be considered in cost-effectiveness models informing vaccine choice and models to shape the future of cervical screening programmes

Functional significance may underlie the taxonomic utility of single amino acid substitutions in conserved proteins

We hypothesized that some amino acid substitutions in conserved proteins that are strongly fixed by critical functional roles would show lineage-specific distributions. As an example of an archetypal conserved eukaryotic protein we considered the active site of ß-tubulin. Our analysis identified one amino acid substitution—ß-tubulin F224—which was highly lineage specific. Investigation of ß-tubulin for other phylogenetically restricted amino acids identified several with apparent specificity for well-defined phylogenetic groups. Intriguingly, none showed specificity for “supergroups” other than the unikonts. To understand why, we analysed the ß-tubulin Neighbor-Net and demonstrated a fundamental division between core ß-tubulins (plant-like) and divergent ß-tubulins (animal and fungal). F224 was almost completely restricted to the core ß-tubulins, while divergent ß-tubulins possessed Y224. Thus, our specific example offers insight into the restrictions associated with the co-evolution of ß-tubulin during the radiation of eukaryotes, underlining a fundamental dichotomy between F-type, core ß-tubulins and Y-type, divergent ß-tubulins. More broadly our study provides proof of principle for the taxonomic utility of critical amino acids in the active sites of conserved proteins

Compact HI clouds from the GALFA-HI survey

The Galactic Arecibo L-band Feed Array HI (GALFA-HI) survey is mapping the entire Arecibo sky at 21-cm, over a velocity range of -700 to +700 km/s (LSR), at a velocity resolution of 0.18 km/s and a spatial resolution of 3.5 arcmin. The unprecedented resolution and sensitivity of the GALFA-HI survey have resulted in the detection of numerous isolated, very compact HI clouds at low Galactic velocities, which are distinctly separated from the HI disk emission. In the limited area of ~4600 deg$^2$ surveyed so far, we have detected 96 of such compact clouds. The detected clouds are cold with a median T$_{k,max}$ (the kinetic temperature in the case in which there is no non-thermal broadening) of 300 K. Moreover, these clouds are quite compact and faint, with median values of 5 arcmin in angular size, 0.75 K in peak brightness temperature, and $5 \times 10^{18}$ cm$^{-2}$ in HI column density. Most of the clouds deviate from Galactic rotation at the 20-30 km/s level, and a significant fraction show evidence for a multiphase medium and velocity gradients. No counterparts for these clouds were found in other wavebands. From the modeling of spatial and velocity distributions of the whole compact cloud population, we find that the bulk of the compact clouds are related to the Galactic disk, and their distances are likely to be in the range of 0.1 to a few kpc. We discuss various possible scenarios for the formation and maintenance of this cloud population and its significance for Galactic ISM studies.Comment: Accepted for publication in the Astrophysical Journa

The role of gender in the relations among Dark Triad and psychopathy, sociosexuality, and moral judgments

The Dark Triad (D3) traits of narcissism, Machiavellianism, and psychopathy have been linked to a range of moral behavior, and to sociosexuality and sexual behavior, particularly in males. The current study examined whether males and females differ with respect to relations among D3 traits and dimensions of psychopathy from the Triarchic Psychopathy Measure (TriPM), sexual behavior, sociosexuality, tendency towards infidelity, and moral judgments, using a community sample. D3 and TriPM measures were generally more strongly correlated with sexual behavior for males in ways that might increase numbers of matings and sexual partners, but were more strongly correlated with intention towards infidelity and sociosexual attitudes for females—in ways that might facilitate extra-pair mating. Sociosexuality and self-reported sexual behavior showed a strong pattern of overall and gender-specific relations to moral judgments. D3 and psychopathy measures were also related to everyday moral judgments, although generally less so than were sociosexuality and sexual behavior. These results clearly point to the importance of taking gender into account when considering the relations between D3 traits, sexual behavior, sociosexuality, and moral judgments

Reflections on Sculptural Thinking in Fashion Design

This paper explores three-dimensional thinking in fashion design; it does this by engaging with theories, concepts and philosophies related to thought and the experience of creating three-dimensional artifacts, which are common to both sculpture and fashion. Central to this relationship is the employment of the senses with respect to perception and cognition. Of particular interest is the sense of touch,and how sensory experience encounters notions of empathy and mimicry in a phenomenological encounter with others: whether animate or inanimate. The research emerged through conversations between a fashion designer, Kevin Almond and a contemporary artist, Stephen Swindells. The sensibility of the paper, and much ofthe analysis and debates, thus adopt a creative practitioners perspective. A conceptual current running through the conversation, and subsequently the paper, touched upon whether following a line of thought becomes analogous to visually and mentally tracing a human form in a psychological space – and what is the significance for fashion of the interrelationships between sculptural thinking and phenomenological encounters with others within urban environments