Sex differences in the associations between birthweight and lipid levels in middle-age: findings from the 1958 British birth cohort

Objective To examine sex differences in birthweight–lipid associations. Methods and results Using prospectively collected data on birthweight and non-fasting lipid levels at age 44–45 y from the 1958 British birth cohort (3603 men and 3583 women), sex differences in birthweight–lipid associations were examined. There were inverse associations between birthweight and total and low-density-lipoprotein (LDL)-cholesterol among women (a 1 kg increase in birthweight was associated with a 0.13 mmol/L reduction in total cholesterol (p < 0.001) and a 0.07 mmol/L reduction in LDL-cholesterol (p = 0.02)) but no associations among men (p = 0.005 and p = 0.01, respectively, for birthweight × sex interactions). There was an inverse association between birthweight and triglycerides of a similar magnitude in both sexes (a 1 kg increase in birthweight was associated with a 7% reduction in triglyceride levels in sex-adjusted models (p < 0.001)). There was no association between birthweight and high-density-lipoprotein-cholesterol. Associations were largely unaltered after adjustment for covariates. Of birthweight, current height and BMI, the latter was the strongest predictor of lipid levels. Conclusions The finding of an inverse association between birthweight and triglycerides in both sexes and of inverse associations between birthweight and total and LDL-cholesterol only in women suggests that the mechanisms underlying the associations with birthweight may vary for different lipids

Electronic transport in graphene nanoribbons with sublattice-asymmetric doping

Recent experimental findings and theoretical predictions suggest that nitrogen-doped CVD-grown graphene may give rise to electronic band gaps due to impurity distributions which favour segregation on a single sublattice. Here we demonstrate theoretically that such distributions give rise to more complex behaviour in the presence of edges, where geometry determines whether electrons in the sample view the impurities as a gap-opening average potential or as scatterers. Zigzag edges give rise to the latter case, and remove the electronic bandgaps predicted in extended graphene samples. We predict that such behaviour will give rise to leakage near grain boundaries with a similar geometry or in zigzag-edged etched devices. Furthermore, we examine the formation of one-dimensional metallic channels at interfaces between different sublattice domains, which should be observable experimentally and offer intriguing waveguiding possibilities.Comment: 6 pages, 6 figures, published in PR

Power sums and Homfly skein theory

The Murphy operators in the Hecke algebra H_n of type A are explicit commuting elements, whose symmetric functions are central in H_n. In [Skein theory and the Murphy operators, J. Knot Theory Ramif. 11 (2002), 475-492] I defined geometrically a homomorphism from the Homfly skein C of the annulus to the centre of each algebra H_n, and found an element P_m in C, independent of n, whose image, up to an explicit linear combination with the identity of H_n, is the m-th power sum of the Murphy operators. The aim of this paper is to give simple geometric representatives for the elements P_m, and to discuss their role in a similar construction for central elements of an extended family of algebras H_{n,p}.Comment: Published by Geometry and Topology Monographs at http://www.maths.warwick.ac.uk/gt/GTMon4/paper15.abs.htm

A postal survey to identify and describe nurse led clinics in genitourinary medicine services across England

Background: Nurses in genitourinary medicine (GUM) services are progressively extending their roles to conduct "comprehensive care" nurse led clinics. In such roles the nurse coordinates the first line, comprehensive care of patients presenting with sexual health conditions and issues. Objectives: To identify and describe comprehensive care nurse led clinics in GUM services across England. Methods: A postal questionnaire consisting of 17 closed response questions was sent to 209 GUM services across England. A second questionnaire was sent to non-responders to increase the response rate. Data were single entered and analysed using SPSS. Results: Of the 190 GUM clinic respondents (91% response rate), 44 (23%) reported providing some form of comprehensive care nurse led clinic, 90% of which were initiated since 1995. Key results show staff development featured as the main reason for initiating such services and there was general consistency in the aspects of care undertaken by these nurses. There was evidence of guideline development specific to nurse led care and some patient group direction use for supplying medication. The level of support from medical staff while nurse led clinics were being conducted varied between services. Few services have conducted any audit or research to monitor/evaluate nurse led care. There was little consistency in the clinical experience and educational prerequisites to undertake comprehensive care nurse led clinics. Continuing professional development opportunities also varied between services. Conclusions: The steady growth of comprehensive care nurse led clinics indicates that the skills of GUM nurses are being recognised. Nurses working in advanced practice roles now require courses and study days reflecting these changes in practice. Locally agreed practice guidelines can define nursing practice boundaries and ensure accountability, as will the development of patient group directions to supply medication. Monitoring and evaluation of nurse led clinics also require attention

Pseudomagnetic fields and triaxial strain in graphene

Strain fields in graphene giving rise to pseudomagnetic fields have received much attention due to the possibility of mimicking real magnetic fields with magnitudes of greater than 100 Tesla. We examine systems with such strains confined to finite regions ("pseudomagnetic dots") and provide a transparent explanation for the characteristic sublattice polarization occurring in the presence of pseudomagnetic field. In particular, we focus on a triaxial strain leading to a constant field in the central region of the dot. This field causes the formation of pseudo Landau levels, where the zeroth order level shows significant differences compared to the corresponding level in a real magnetic field. Analytic arguments based on the Dirac model are employed to predict the sublattice and valley dependencies of the density of states in these systems. Numerical tight binding calculations of single pseudomagnetic dots in extended graphene sheets confirm these predictions, and are also used to study the effect of the rotating the strain direction and varying the size of the pseudomagnetic dot