On the equivalence between hierarchical segmentations and ultrametric watersheds

We study hierarchical segmentation in the framework of edge-weighted graphs. We define ultrametric watersheds as topological watersheds null on the minima. We prove that there exists a bijection between the set of ultrametric watersheds and the set of hierarchical segmentations. We end this paper by showing how to use the proposed framework in practice in the example of constrained connectivity; in particular it allows to compute such a hierarchy following a classical watershed-based morphological scheme, which provides an efficient algorithm to compute the whole hierarchy.Comment: 19 pages, double-colum

The Prediction of Depression in the Postpartum Period

Eight thousand five hundred and fifty-six women enrolled in the Mater-University of Queensland Study of Pregnancy were surveyed to investigate the relationship between potential risk factors for depression and mood states in the postpartum period. Participants were followed from their first antenatal interview until 6 months postpartum. Level of depression was measured at the first interview using the Delusions Signs and Symptoms Inventory (DSSI) and again at 6 months postpartum. A second measure of depression, which was prototypical in nature and related to the maternity blues, was administered retrospectively to cover the 6 month period following parturition. the assessment of independent variables during pregnancy and/or the postpartum period included demographic data and several measures of: neonatal risk, stress and social adjustment. Having excluded from analysis, participants who were depressed at the initial interview a point prevalence for depression of 2.6% (measured by the DSSI) and a prevalence for severe and prolonged postpartum stress of 12.8% (using the prototype measure) was recorded. Data was analysed using categorical modelling techniques and multiple regression analysis. Linear models were constructed to predict, both, DSSI and prototype measures of depression. Predictor variables accounted for 17% of the variance in DSSI scores and only 7% in the prototype measure. Whilst stress and social support formed the core of both models, irrespective of the analysis used, neonatal risk variables were more strongly predictive of 'blues' related depression. Inconsistencies in results are discussed and the need to differentiate between postpartum depression and depression (unrelated to childbirth) occurring in the postpartum period is proposed. Implications for primary prevention are discussed

Sibling Influences on Adolescent Delinquent Behaviour: An Australian Longitudinal Study

This article examines sibling influences on adolescent delinquency at age 14, using data from an Australian longitudinal study of 374 same- and mixed-sex sibling pairs. Based on maternal and self-reports, a moderately strong association between siblings' delinquency is found. The relationship remains significant controlling for childhood aggression and family environment factors measured during childhood (age 5) and adolescence (age 14), using both standardized instruments and new scales. This effect varies according to the sex composition of the sibling pair and is stronger for males and those whose parents have been arrested. The need for increased attention to sibling influences by researchers and prevention practitioners is discussed

The Relative Contributions Of Parental And Sibling Substance Use To Adolescent Tobacco, Alcohol, And Other Drug Use

While research demonstrates that parental tobacco and alcohol use increases the likelihood of children's substance use, it is unclear whether or not sibling use has a greater, weaker, or similar effect. Based upon self-reported information from Australian adolescents, their siblings and parents, this investigation examines the association between siblings' tobacco and alcohol use. The relationship is consistent, moderately strong, and remains significant when controlling for a number of family-related factors, indicating that the shared environment cannot fully explain the extent of similarity in siblings' behaviors. In addition, sibling substance use has a greater effect on adolescent substance use than does smoking or drinking by parents. These findings indicate the need to include siblings and information regarding sibling relationships in prevention and intervention programs

Socio-Economic Status Differences in Patients' Desire for and Capacity to Obtain Information in the Clinical Encounter

As individual long-term doctor/patient relationships are increasingly replaced by more transient specialist and group practice contacts, there are likely to be growing doubts about the quality of overall care and communication. One aspect in particular of the quality of medical care involves the communication of information to patients (Donabedian 1980). Previous studies have pointed to a significant level of discontent with the amount and quality of information received by patients from their doctors (Cartright 1979; Boreham & Gibson 1978; Pendleton and Bochner 1980; Reid and McIlwaine 1980; Graham and Oakley 1981)

A Fast, Memory-Efficient Alpha-Tree Algorithm using Flooding and Tree Size Estimation

The alpha-tree represents an image as hierarchical set of alpha-connected components. Computation of alpha-trees suffers from high computational and memory requirements compared with similar component tree algorithms such as max-tree. Here we introduce a novel alpha-tree algorithm using 1) a flooding algorithm for computational efficiency and 2) tree size estimation (TSE) for memory efficiency. In TSE, an exponential decay model was fitted to normalized tree sizes as a function of the normalized root mean squared deviation (NRMSD) of edge-dissimilarity distributions, and the model was used to estimate the optimum memory allocation size for alpha-tree construction. An experiment on 1256 images shows that our algorithm runs 2.27 times faster than Ouzounis and Soille's thanks to the flooding algorithm, and TSE reduced the average memory allocation of the proposed algorithm by 40.4%, eliminating unused allocated memory by 86.0% with a negligible computational cost

Employment, Unemployment and the Health of Pregnant Women

Much of what little we know about the impact of unemployment or health is based upon data or studies of predominantly unemployed men. These studies, though weak in methodology, imply that unemployment may lead to excess morbidity and mortality. This paper reports a study of 4,000 pregnant women in Brisbane. Unemployment amongst women is associated with high-risk health behaviour, which in turn may lead to low birthweight births. Further, unemployed women are more anxious and depressed than are employed women. The mental health of the mother appears to be more closely related to the employment status of her spouse than to her own employment status

Unemployment and Reproductive Outcome: An Australian study

The Mater-University of Queensland Study involves the follow-up of 8556 pregnant women who were enrolled at their first clinic visit. This analysis compares four groups of women categorized according to their own and their partners' employment status. Group 1 comprised women unemployed, partners not unemployed. Group 2 comprised women not unemployed with unemployed partners. Group 3 comprised women and partners who were both unemployed. In group 4 neither partner was unemployed. Initial analysis showed that there was a significant association between birthweight and birthweight for gestational age, and unemployment as reported by mothers. After adjustment for lifestyle variables (principally smoking) there were no remaining statistically significant associations

Social Class, Religion And Contraceptive Failure In A Sample Of Pregnant Women In Brisbane

The reproductive intent of women at the time of conception has been largely ignored in the social science and epidemiological literature. This is surprising in view of its likely relevance to a wide range of health and welfare issues. Despite the possible short and long term consequences of unplanned reproductive activity, it appears that we know a good deal more about the factors influencing decisions to acquire many consumer goods than we do about the factors influencing the decision to reproduce. The easy availability of contraception and a high level of literacy may contribute to an assumption that women have considerable control over their fertility. The received wisdom relating to reproductive intent suggests that most women are pregnant because they planned their pregnancy. In this study a large sample (4000) of pregnant women were asked about the beginning of their pregnancies. Women were specifically asked about the method of contraception they last used and whether their pregnancy was a consequence of a failure of contraception. Social, economic and religious variables were examined to assess the extent to which these were associated with differing rates of contraceptive failure