Automorphisms, Non-linear Realizations and Branes

The theory of non-linear realizations is used to derive the dynamics of the branes of M theory. A crucial step in this procedure is to use the enlarged automorphism group of the supersymmetry algebra recently introduced. The field strengths of the worldvolume gauge fields arise as some of the Goldstone fields associated with this automorphism group. The relationship to the superembedding approach is given.Comment: 17 pages, plain tex, corrected some typos and two references adde

Hidden Superconformal Symmetry in M Theory

The bosonic sectors of the eleven dimensional and IIA supergravity theories are derived as non-linear realisations. The underlying group includes the conformal group, the general linear group and as well as automorphisms of the supersymmetry algebra. We discuss the supersymmetric extension and argue that Osp(1/64) is a symmetry of M theory. We also derive the effective action of the closed bosonic string as a non-linear realisation.Comment: 20 pages, plain tex, some typos corrected and two references adde

Physical States and String Symmetries

It is shown that if the momenta belong to an integral lattice, then every physical state of string theory leads to a symmetry of the scattering amplitudes. We discuss the role of this symmetry when the momenta are those provided by the usual D.D.F construction and show that the string compactified on the torus associated with the self-dual Lorentzian lattice, $\Pi^{25,1}$ possess the Fake Monster Lie algebra as a symmetry.Comment: 14 pages, ( Some references are added.

Generalised BPS conditions

We write down two E11 invariant conditions which at low levels reproduce the known half BPS conditions for type II theories. These new conditions contain, in addition to the familiar central charges, an infinite number of further charges which are required in an underlying theory of strings and branes. We comment on the application of this work to higher derivative string corrections

Social class and smoking at age 15: the effect of different definitions of smoking

Aim : To explore whether the association between social class and smoking among teenagers varies according to the definition of smoking adopted. Design, setting and participants : A survey of 2196 15-year-olds in 43 secondary schools in the West of Scotland. Measures : Current smoking status and number of cigarettes smoked, and social class based on the occupation of the head of the household. Findings : 'Current smoker' was the only category not significantly differentiated by class; the ratio of smokers from unskilled compared with professional backgrounds rose with increasingly stringent definitions of smoking. Conclusion : The extent to which teenage smoking is patterned by social class depends on the definition of smoking adopted

Gender differences in weight-related concerns in early to mid adolescence

Among adults, women are more likely than men to perceive themselves as too heavy for their height, the gender discrepancy being greatest among those within a "normal" weight range. This finding has been explained in terms of the equation of female beauty with extreme thinness. As the physical changes of puberty are differentiated by gender, with males experiencing increased skeletal and muscle mass but females a gain in fat, this life stage has been seen as key for the development of female body dissatisfaction and associated problems such as lowered self esteem and eating disorders. In this analysis we compare changes in worries about putting on weight and dieting with actual body mass index at ages 11, 13, and 15

Being different: correlates of the experience of teasing and bullying at age 11

The public stereotype, largely supported by a rather diverse range of literature, is that bullied children differ from their peers in respect of attributes such as appearance, disability or school performance. In this paper we explore the characteristics of such victims in a way which is both more comprehensive than previous studies and in addition, considers and accounts for possible inter-relationships between variables. Self-report data on teasing and bullying (found to be strongly inter-related) were obtained from a large, school-based sample of 11 year-olds, with additional descriptions and ratings of the children from their parents, class teachers and nurses. Experience of teasing/bullying did not differ according to race, physical maturity or height, but was more likely among children who were less physically attractive, overweight, had a disability such as a sight, hearing or speech problem, and performed poorly at school. These factors were not only significant regardless of sex and social class, but also independent and thus additive in their effects. Characteristics of appearance, disability or ability which in themselves may be difficult to deal with also increase the likelihood that a child will experience the additional burden of being bullied

Young people's leisure and risk-taking behaviours: changes in gender patterning in the West of Scotland during the 1990s

Until the 1990s, the literature on youth leisure characterized that of females as home-based, passive and largely absent from male-dominated subcultures. Contrasting with this, over the course of the 1990s, evidence emerged of increasing public visibility, reduced restrictions on activities and relatively greater increases in health-risk behaviours among females, together with suggestions of a domestification of leisure among males This paper uses data from two cohorts of 15 year olds in the same geographical area (the West of Scotland), separated by 12 years (1987 and 1999) to examine changes in the gender patterning of young people's leisure, use of public space and risk taking (as represented by substance use) over this time period. Gender differences in 'street-based' (previously more males) and 'conventional/safe' (previously more females) leisure disappeared over this period while male excesses in watching sports and playing computer games increased. At the same time, female levels of drinking and experience of illicit drugs reached, and those of smoking overtook, their male counterparts. Additional analyses showed that changes in leisure activities over time accounted in part for the changing gender patterns in substance use. The paper discusses how greater public visibility and increased risk-taking behaviours among females have resulted from the lifting of constraints of respectability on young women's life- styles. These changes have been rapid and have significance in both social and health terms

Duality Symmetries and G^{+++} Theories

We show that the non-linear realisations of all the very extended algebras G^{+++}, except the B and C series which we do not consider, contain fields corresponding to all possible duality symmetries of the on-shell degrees of freedom of these theories. This result also holds for G_2^{+++} and we argue that the non-linear realisation of this algebra accounts precisely for the form fields present in the corresponding supersymmetric theory. We also find a simple necessary condition for the roots to belong to a G^{+++} algebra.Comment: 35 pages. v2: 2 appendices added, other minor corrections. v3: tables corrected, other minor changes, one appendix added, refs. added. Version published in Class. Quant. Gra