Peak bone mineral accrual and age at menarche in adolescent girls: A 6-year longitudinal study

Background and objectives: The greatest increase in bone mineral content occurs during adolescence. The amount of bone accrued may significantly affect bone mineral status in later life. We carried out a longitudinal investigation of the magnitude and timing of peak bone mineral content velocity (PBMCV) in relation to peak height velocity (PHV) and the age at menarche in a group of adolescent girls over a 6-year period. Methods: The 53 girls in this study are a subset of the 115 girls (initially 8 to 16 years) in a g-year longitudinal study of bone mineral accretion. The ages at PBMCV and PHV were determined by using a cubic spline curve fitting procedure. Determinations were based on height (n = 12) and bone (n = 6) measurements over 6 years. Results: The timing of PBMCV and menarche were coincident, preceded approximately 1 year earlier by PHV. Correlation showed a negative relationship between age at menarche and both peak bone mineral accrual (r = -0.42, P

Spider toxins: A new group of potassium channel modulators

Spider toxins that target potassium channels constitute a new class of pharmacological tools that can be used to probe the structure and function of these channels at the molecular level. The limited studies performed to date indicate that these peptide toxins may facilitate the analysis of K+ channels that have proved insensitive to peptide inhibitors isolated from other animal sources. Thus far, two classes of K+ channel-selective spider toxins have been isolated, sequenced, and pharmacologically characterised - the hanatoxins (HaTx) from Grammastola spatulata and heteropodatoxins (HpTx) from Heteropoda venatoria. The hanatoxins block Kv2.1 and Kv4.2 voltage-gated K+ channels. In Kv2.1 K+ channels this occurs as a consequence of a depolarising shift in the voltage dependence of activation and not by occlusion of the channel pore. These toxins show minimal sequence homology with other peptide inhibitors of K+ channels, but they do share some homology with other ion channel toxins from spiders, particularly with regard to the spacing between cysteine residues. We have recently isolated three K+ channel antagonists from the venom of the Australian funnel-web spider Hadronyche versuta; at least two of these toxins are likely to constitute a new class of spider toxins active on K+ channels as they are approximately twice as large as HaTx and HpTx.

Some challenging group presentations

We study some challenging presentations which arise as groups of deficiency zero. In four cases we settle finiteness: we show that two presentations are for finite groups while two are fur infinite groups. Thus we answer three explicit questions in the literature and we provide the first published deficiency zero presentation for a group with derived length seven. The tools we use are coset enumeration and Knuth-Bendix rewriting, which are well-established as methods for proving finiteness or otherwise of a finitely presented group. We briefly comment on their capabilities and compare their performance.

Challenge of reducing drug-related deaths

The public-health attention given to deaths caused by illicit drug use in general, and by drug overdose in particular, should be commensurate with their contribution to premature death. For too long these deaths have been regarded as an unavoidable hazard of illicit drug use, their neglect abetted by the implicit view that the lives of illicit drug users are less deserving of being saved than those of others. In its report published this week,1 the UK Advisory Council on the Misuse of Drugs (ACMD) has rejected these implicit assumptions. Its view is that “drug-related deaths can, will and must in the near future be radically reduced in number”. It points out that the effort that society expends on preventing premature deaths “should apply no less to drug misusers than it does to other classes of people”.1

Prejudiced attitudes, group norms, and discriminatory behaviour

Most current attitude research focuses on range of non-social attitudinal targets, including health-related and consumer outcomes. In this paper, a program of research that considers the relations among intergroup attitudes, group norms, and behavior will be described. The first study examined the effect of ingroup norms relating to multiculturalism on the extent to wich participants hehaviourally enacted their attitudes. Consistent with social identity theory, attitudebehaviour consistency in relation was influenced by ingroup norms, particularly when national identity was salient. The results of a large scale field study that essential replicated this pattern of results will also be discussed.

Self-awareness and psychosocial functioning following acquired brain injury: An evaluation of a group support programme

This study investigated a group support programme designed to improve self-awareness deficits and psychosocial functioning in a group of chronic patients (N = 21) with acquired brain injury (ABI). The participants were on average 8.6 years (range: 1-36 years) post-injury and were seen at the Brain Injury Association of Queensland, Australia. The assessment of participants involved two standardised measures of intellectual self-awareness with collateral reports from relatives. The present study introduced a new measure called the Self-Regulation Skills Interview (SRSI) which assessed higher levels of self awareness and self-regulation skills. Psychosocial functioning was assessed using a standardised self-report measure. At baseline the group had a relatively high level of intellectual self-awareness regarding their deficits, a low to moderate level of self-regulation skills, and significant psychosocial impairment. The participants were involved in a 16-week group programme which involved components of cognitive rehabilitation, cognitive-behavioural therapy, and social skills training. A post-intervention assessment indicated that participants had significantly improved levels of self-regulation skills and psychosocial functioning. A 6-month follow-up assessment indicated that overall, participants had maintained the gains made during the programme. The important role of self-regulation skills is emphasised as the principle factor contributing to the maintenance of the gains observed.

The burden of mental disorders in Victoria, 1996

Background: Between 1998 and 1999, a burden of disease assessment was carried out in Victoria, Australia applying and improving on the methods of the Global Burden of Disease Study. This paper describes the methods and results of the calculations of the burden due to 22 mental disorders, adding 14 conditions not included in previous burden of disease estimates, Methods: The National Survey of Mental Health and Wellbeing provided recent data on the occurrence of the major adult mental disorders in Australia. Data from international studies and expert advice further contributed to the construction of disease models, describing each condition in terms of incidence, average duration and level of severity, with adjustments for comorbidity with other mental disorders. Disability weights for the time spent in different states of mental ill health were borrowed mainly from a study in the Netherlands, supplemented by weights derived in a local extrapolation exercise. Results: Mental disorders were the third largest group of conditions contributing to the burden of disease in Victoria, ranking behind cancers and cardiovascular diseases. Depression was the greatest cause of disability in both men and women. Eight other mental disorders in men and seven in women ranked among the top twenty causes of disability. Conclusions: Insufficient information on the natural history of many of the mental disorders, the limited information on the validity of mental disorder diagnoses in community surveys and considerable differences between ICD-10 and DSM-IV defined diagnoses were the main concerns about the accuracy of the estimates. Similar and often greater concerns have been raised in relation to the estimation of the burden from common non-fatal physical conditions such as asthma, diabetes and osteoarthritis. In comparison, psychiatric epidemiology can boast greater scientific rigour in setting standards for population surveys.

The prevention of mental disorders in young people

The prevention of some mental disorders in young people appears to be possible. Several small and medium randomised controlled trials show that some anxiety, affective and substance-use disorders can be prevented. These trials show that the interventions are efficacious, but whether they will be effective in routine practice is not known. The evidence is sufficiently good to warrant a large community trial in which the roll-out is staged and school communties evaluated before and after the roll-out.

Group theory and quasiprobability integrals of Wigner functions

The integral of the Wigner function of a quantum-mechanical system over a region or its boundary in the classical phase plane, is called a quasiprobability integral. Unlike a true probability integral, its value may lie outside the interval [0, 1]. It is characterized by a corresponding selfadjoint operator, to be called a region or contour operator as appropriate, which is determined by the characteristic function of that region or contour. The spectral problem is studied for commuting families of region and contour operators associated with concentric discs and circles of given radius a. Their respective eigenvalues are determined as functions of a, in terms of the Gauss-Laguerre polynomials. These polynomials provide a basis of vectors in a Hilbert space carrying the positive discrete series representation of the algebra su(1, 1) approximate to so(2, 1). The explicit relation between the spectra of operators associated with discs and circles with proportional radii, is given in terms of the discrete variable Meixner polynomials.

Molecular evidence for definition of genera in the Oxylobium group (Fabaceae : Mirbelieae)

The circumscription of Oxylobium and related genera has been problematic for nearly 200 years. Traditional definitions of genera in the group have relied on morphological features of the leaves, flower, and fruit that overlap extensively between genera. Therefore sequences of cpDNA (trnL-F intron and spacer) and nrDNA (ITS) were used to estimate the phylogeny of the group in an attempt to redefine the genera as monophyletic groups. Oxylobium sens. str. was found to be a well supported clade in both data sets, with the inclusion of Mirbelia oxylobioides. No other genus in the group was supported by these data, except Gastrolobium sens. lat. Some species groups within Chorizema, Mirbelia, and Podolobium were supported but relationships among these, Oxylobium and Gastrolobium differed significantly between the chloroplast and nuclear data sets. No group supported by the molecular data had a morphological synapomorphy, not even Oxylobium or Gastrolobium. Therefore it may be necessary to adopt a much broader generic concept in this group than has been done previously. Incongruence between the two molecular data sets, and very short internal basal branches in both, suggest a rapid early radiation in this group, possibly combined with hybridization and lineage sorting.