Determinants of maternity leave duration in Australia : evidence from the HILDA survey

We use the first five waves of the Household, Income and Labour Dynamics in Australia survey to examine what determines the maternity leave taken by pre-birth employed mothers of newborn children in Australia. We find that the difficulties faced by mothers in finding appropriate child care in terms of both cost and quality hinder them from returning to the labour market following childbirth. Maternity leave entitlements lead to an earlier return to the labour market following the birth of a child, relative to those who have no leave rights at all. Mothers with higher wages in their pre-birth employment and mothers with higher education levels tend to return to the labour market earlier than their lower wage and less educated counterparts. More flexible pre-birth jobs are associated with an increase in the likelihood of mothers returning to the workforce earlier than the average. Household wealth, however, seems to play a facilitating role in mothers taking a longer period of maternity leave to look after the newborn child. That is, mothers who have higher wealth levels can ‘afford’ to stay on maternity leave longer, to look after their children better during their primary developmental months. We believe that this article provides useful insights into the employment transitions of Australian mothers after having a baby.

A despecialization step underlying evolution of a family of serine proteases

In the trypsin superfamily of serine proteases, non-trypsin-like primary specificities have arisen in only two monophyletic descendent subbranches. We have recreated an ancestor to one of these subbranches (granzyme) using phylogenetic inference, gene synthesis, and protein expression. This ancestor has two unusual properties. First, it has broad primary specificity encompassing the entire repertoire of novel primary specificities found in its descendents. Second, unlike extant members that have narrow primary specificities, the ancestor exhibits tolerance to mutational changes in primary specificity-conferring residues—that is, structural plasticity. Molecular modeling and mutagenesis studies indicate that these unusual properties are due to a particularly wide substrate binding pocket. These two crucial properties of the ancestor not only distinguish it from its extant descendents but also from the trypsin-like proteases that preceded it. This indicates that a despecialization step, characterized by broad specificity and structural plasticity, underlies evolution of new primary specificities in this protease superfamily.

Determinants of local abundance in a major radiation of Australian passerines (Aves: Meliphagoidea)

Aim  To identify the factors that contribute to variation in abundance (population density), and to investigate whether habitat breadth and diet breadth predict macroecological patterns in a suborder of passerine birds (Meliphagoidea).
Location  Australia (including Tasmania).
Methods  Mean abundance data were collated from site surveys of bird abundance (the Australian Bird Count); range size and latitudinal position data from published distribution maps; and body mass and diet breadth information from published accounts. A diversity index of habitats used (habitat breadth) was calculated from the bird census data. We used bivariate correlation and multiple regression techniques, employing two phylogenetic comparative methods: phylogenetic generalized least squares and independent contrasts.

Results  Body mass and latitude were the only strong predictors of abundance, with larger-bodied and lower-latitude species existing at lower densities. Together, however, body mass and latitude explained only 11.1% of the variation in mean abundance. Range size and habitat breadth were positively correlated, as were diet breadth and body mass. However, neither range size, nor habitat breadth and diet breadth, explained patterns in abundance either directly or indirectly.
Main conclusions  Levels of abundance (population density) in meliphagoid birds are most closely linked to body mass and latitudinal position, but not range size. As with many other macroecological analyses, we find little evidence for aspects of niche breadth having an effect on patterns of abundance. We hypothesize that evolutionary age may also have a determining effect on why species tend to be rarer (less abundant) in the tropics.

The underlying assumption in chemistry education

The underlying assumption in chemistry education is that chemistry is real, distinct discipline, clearly differentiable from other sciences. Chemistry is the study of matter and its interactions with other matter and with energy, but the aspects which distinguish chemistry are: macroscopic observations and descriptions of properties and change; understanding in terms of atoms and molecules; abstract representations to describe and communicate chemical concepts; and occupational health and safety. These aspects are not unique to chemistry, but their combination make chemistry unique. Over the last three years, there have been major reviews of school science education through the formulation of the Australian National Curriculum and of undergraduate education through the Learning and Teaching Academic Standards Project. In both cases, individual RACI members and chemistry professionals, including school teachers, and RACI working party and workshop, have articulated the unique nature of chemistry and the need for chemistry education as a separate subject.

Determinants of permanent first incisor eruption in grazing Australian Angora goats

Objective: To investigate the effects of live weight, sex and other factors on deciduous (first incisor) loss and permanent first incisor development in Angora goats. Design: Goats were part of a pen study on the effects of energy intake in Angora does during pregnancy and lactation on kid growth and development. The design was three levels of nutrition in mid-pregnancy × two levels of postnatal nutrition in 17 randomised blocks. Methods: Conception times were calculated by using artificial insemination, with ultrasound examination 43 days after insemination. Does were fed different amounts of a formulated diet in their pens. After weaning, goats were grazed in sex groups. Deciduous first incisor loss and permanent first incisor development were recorded at 11 time points from 14 to 20 months of age. Results: For each sex, the time for visible eruption and full development of permanent first incisor declined linearly with increased live weight by 5.9 and 5.4 days/kg live weight, respectively. The time to reach similar development stages for first permanent incisors eruption was 3 months longer for the lightest animals compared with the heaviest animals. Date of birth, birth weight, doe age, growth rates, mid-pregnancy and postnatal nutrition, parity, day of weaning and weaning weight had no detectable effect. Conclusions: The results explain much of the substantial range in reported first permanent incisor eruption dates for small ruminants and have application in ageing of goats, marketing of kids for meat, in the selection of animals for breeding flocks and in educational material.

Determinants of capital structure of A-REITS and the global financial crisis

This paper contributes to the capital structure literature by investigating the determinants of capital structure of Australian Real Estate Investment Trusts (A-REITs) over the period 2006-2009. By using a panel approach and a Global Financial Crisis (GFC) dummy variable, our analysis incorporates the Global Financial Crisis (GFC) shock which appears to have affected the market after December 2007. We find that A-REIT size, profitability, tangibility, operating risk and number of growth opportunities impact similarly to many previous studies of international entities upon the degree of leverage. We also find mixed support for prevailing capital structure theories of Pecking Order, Trade-off and Agency Theory, but find that Market Timing Theory can be rejected over our sample period. With specific focus after onset of the GFC, we find that the relationship between capital structure and our independent variables is somewhat distorted. Consequently, the postulations of theory also become distorted whereby changes to capital structure come about because of the primary goal to survive, rather than managerial opportunism.

Prevalence of vitamin D deficiency and its determinants in Australian adults aged 25 years and older : a national, population-based study

Objective  Vitamin D deficiency is recognized as a global public health problem, but the population-based prevalence of deficiency and its determinants in Australian adults is not known. This study evaluated the vitamin D status of Australian adults aged ≥25 years and risk factors associated with vitamin D deficiency in this population.

Design and Patients  We studied a national sample of 11 247 Australian adults enrolled in the 1999/2000 Australian Diabetes, Obesity and Lifestyle (AusDiab) study drawn from 42 randomly selected districts throughout Australia.

Measurements  Serum concentrations of 25-hydroxyvitamin D [25(OH)D] were measured by immunoassay. Vitamin D deficiency was defined as a concentration <50 nmol/l. Information on demographic and lifestyle factors was derived from interview-administered questionnaires.

Results  The mean serum 25(OH)D concentration was 63 nmol/l (95% CI: 59–67 nmol/l). Only 4% of the population had a level <25 nmol/l, but the prevalence of vitamin D deficiency (<50 nmol/l) was 31% (22% men; 39% women); 73% had levels <75 nmol/l. The prevalence of vitamin D deficiency increased significantly with age, was greater in women, in those of non-Europid origin, in the obese and those who were physically inactive and with a higher level of education. Deficiency was also more common during winter and in people residing in southern Australia (latitude >35°S); 42% of women and 27% of men were deficient during summer–autumn, which increased to 58% and 35%, respectively, during winter–spring.

Conclusion  Vitamin D deficiency is common in Australia affecting nearly one-third of adults aged ≥25 years. This indicates that strategies are needed at the population level to improve vitamin D status of Australians.

Home and neighbourhood correlates of BMI among children living in socioeconomically disadvantaged neighbourhoods

A detailed understanding of the underlying drivers of obesity-risk behaviours is needed to inform prevention initiatives, particularly for individuals of low socioeconomic position who are at increased risk of unhealthy weight gain. However, few studies have concurrently considered factors in the home and local neighbourhood environments, and little research has examined determinants among children from low socioeconomic backgrounds. The present study examined home, social and neighbourhood correlates of BMI (kg/m2) in children living in disadvantaged neighbourhoods. Cross-sectional data were collected from 491 women with children aged 5–12 years living in forty urban and forty rural socioeconomically disadvantaged areas (suburbs) of Victoria, Australia in 2007 and 2008. Mothers completed questionnaires about the home environment (maternal efficacy, perceived importance/beliefs, rewards, rules and access to equipment), social norms and perceived neighbourhood environment in relation to physical activity, healthy eating and sedentary behaviour. Children's height and weight were measured at school or home. Linear regression analyses controlled for child sex and age. In multivariable analyses, children whose mothers had higher efficacy for them doing physical activity tended to have lower BMI z scores (B = − 0·04, 95 % CI − 0·06, − 0·02), and children who had a television (TV) in their bedroom (B = 0·24, 95 % CI 0·04, 0·44) and whose mothers made greater use of food as a reward for good behaviour (B = 0·05, 95 % CI 0·01, 0·09) tended to have higher BMI z scores. Increasing efficacy among mothers to promote physical activity, limiting use of food as a reward and not placing TV in children's bedrooms may be important targets for future obesity prevention initiatives in disadvantaged communities.

Have we really thought through health reform?

With all the discussion around about health care reform in Australia we are missing a fundamental issue about health and illness. They are not the same! There is a disconnect between the rhetoric of reform, the apparent political support for prevention and health promotion, and the realities of decisions being taken and understanding of the underlying assumptions of health determinants.Preventing ill health and promoting health have been seen as the point of departure for good health care, at least rhetorically, ever since the Alma Ata Declaration (1978) and the Ottawa Charter (1986). Australia along with other member states of the WHO is signatories to both and they have underpinned official health policy with a rhetorical flourish in many a document since.