Youth suicide trends in Australian metropolitan and non-metropolitan areas, 1988-1997

Objective: The objective of this study was to examine trends in suicide among 15-34-year-olds living in Australian metropolitan and non-metropolitan areas between 1988 and 1997. Method: Suicide and population data were obtained from the Australian Bureau of Statistics. We calculated overall and method-specific suicide rates for 15-24 and 25-34-year-old males and females separately, according to area of residence defined as non-metropolitan (less than or equal to 20 000 people) or metropolitan. Results: Between 1988 and 1997 suicide rates in 15-24-year-old non-metropolitan males were consistently 50% higher than metropolitan 15-24-year-olds. In 1995-1997, for example, the rates were: 38.2 versus 25.1 per 100 000 respectively (p < 0.0001). The reverse pattern was seen in 25-34-year-old females with higher rates in metropolitan areas (7.5 per 100 000) compared with non-metropolitan areas (6.1 per 100 000, p = 0.21) in 1995-1997. There were no significant differences according to area of residence in 25-34-year-old males or 15-24-year-old females. Over the years studied we found no clear evidence that suicide rates increased to a greater extent in rural than urban areas. Rates of hanging suicide have approximately doubled in both sexes and age groups in both settings over this time. Despite an approximate halving in firearm suicide, rates remain 3-fold higher among non-metropolitan residents. Conclusion: Non-metropolitan males aged 15-24 years have disproportionately higher rates of suicide than their metropolitan counterparts. Reasons for this require further investigation. Hanging is now the most favoured method of non-metropolitan suicide replacing firearms from 10 years ago. Although legislation may reduce method-specific suicide the potential for method-substitution means that overall rates may not fall. More comprehensive interventions are therefore required.

Book Review of: Supervising postgraduates from non-English speaking backgrounds

No abstract

Labelled tableaux for non-normal modal logics

In this paper we show how to extend KEM, a tableau-like proof system for normal modal logic, in order to deal with classes of non-normal modal logics, such as monotonic and regular, in a uniform and modular way.

Estimating the cost of contact for non-resident parents: A budget standards approach

Most Western countries have, for some time, provided income support and/or taxation relief to parents with children in their care. The significant amount of research into the costs of children to couple and sole parent households has been important in assessing and developing family support policies. Changing societal expectations about the level of involvement of fathers in child rearing activities has highlighted the need to understand the costs facing usually male non-resident parents in having contact with their children. The budget standards methodology is used in this paper to estimate the costs for non-resident parents exercising regular contact with their children. Costs of contact are found to be high. For contact with one child for 20 per cent of the year, costs of contact represent about 40 per cent of the costs of that same child in an intact couple household with a medium income and more than half of the costs of that child in a household with low income. Household infrastructure and transportation is the reason for high costs. One implication of this finding is that the total cost of children substantially increases when parents separate. The article discusses some policy implications of these findings. This research is of relevance to social security, taxation, family law and child support policies and administration.

Decreased perinatal sunshine duration is associated with increased non-affective but not affective psychosis birth rates

We have previously found an association between variations in schizophrenia birth rates and varyinglevels of perinatal sunshine duration. This study examines whether such an association can also be found for Ža. affective psychosis, and Žb. broadly defined nonaffective psychoses. Data for individuals born between 1931 and 1970 in Australia with ICD9 Other PsychosisŽ295–299.were obtained from the Queensland Mental Health Statistical System. ‘Affective psychosis’ included affective psychosis, schizo-affective psychosis, and depressive and excitative non-organic psychoses. ‘Non-affective psychosis’ included chizophrenia, paranoid disorders and other non-organic psychoses. Those receiving both affective and non-affective psychotic diagnoses were excluded. Rates per 10,000 live monthly general population births were calculated. For each month, we assessed the agreementŽusing the kappa statistic. between trends in Ža. birth rates and Žb. long-term trends in seasonally adjusted perinatal sunshine duration. The analyses were performed separately for males and females. There were 6265 with non-affective psychosis ŽMs3964 rate 66r10,000; Fs2299 44r10,000. and 2858 with affective psychosisŽMs1392 24r10,000; Fs1466 28r10,000.. There were no significant associations between Ža. affective psychosis birth rates for either males or females and Žb. sunshine duration. There was a significant association between nonaffective psychosis birth rates for males only and Žb. sunshine duration Žkappas0.15 p-0.001.. This suggests that, as a risk factor, the effect of reduced perinatal sunshine is specifically associated with males who develop non-affective psychosis. The Stanley Foundation supported this project.

Why do non-color words interfere with color naming?

In the non-color-word Stroop task, university students' response latencies were longer for low-frequency than for higher frequency target words. Visual identity primes facilitated color naming in groups reading the prime silently or processing it semantically (Experiment 1) but did not when participants generated a rhyme of the prime (Experiment 3). With auditory identity primes, generating an associate or a rhyme of the prime produced interference (Experiments 2 and 3). Color-naming latencies were longer for nonwords than for words (Experiment 4). There was a small long-term repetition benefit in color naming for low-frequency words that had been presented in the lexical decision task (Experiment 5). Facilitation of word recognition speeds color naming except when phonological activation of the base word increases response competition.

Variation in the dispersal potential of non-feeding invertebrate larvae: the desperate larva hypothesis and larval size

For many species of marine invertebrates, variability in larval settlement behaviour appears to be the rule rather than the exception. This variability has the potential to affect larval dispersal, because settlement behaviour will influence the length of time larvae are in the plankton. Despite the ubiquity and importance of this variability, relatively few sources of variation in larval settlement behaviour have been identified. One important factor that can affect larval settlement behaviour is the nutritional state of larvae. Non-feeding larvae often become less discriminating in their 'choice' of settlement substrate, i.e. more desperate to settle, when energetic reserves run low. We tested whether variation in larval size (and presumably in nutritional reserves) also affects the settlement behaviour of 3 species of colonial marine invertebrate larvae, the bryozoans Bugula neritina and Watersipora subtorquata and the ascidian Diplosoma listerianum. For all 3 species, larger larvae delayed settlement for longer in the absence of settlement cues, and settlement of Bugula neritina larvae was accelerated by the presence of settlement cues, independently of larval size. In the field, larger W subtorquata larvae also took longer to settle than smaller larvae and were more discriminating towards settlement surfaces. These differences in settlement time are likely to result in differences in the distance that larvae disperse in the field. We suggest that species that produce non-feeding larvae can affect the dispersal potential of their offspring by manipulating larval size and thus larval desperation.