Milk consumption, body composition and pre-weaning growth rates of Australian fur seal

Pre-weaning growth rates, body composition, milk consumption and mass gain efficiency were measured in Australian fur seal Arctocephalus pusillus doriferus pups born in two consecutive breeding periods. Australian fur seals have the highest birth mass of any fur seal species (male 8.3 kg; female 7.2 kg). While their absolute pre-weaning growth rate (male 62 g·day⁻¹; female 53 g·day⁻¹) is similar to that of other temperate latitude fur seals, they have the longest birth-mass doubling time of any otariid species (134–136 days). Daily milk consumption increased from 400 g·day−1 (5 MJ·day−1) after birth to 675 g·day⁻¹ (13.7 MJ·day⁻¹) at age 210 day. However, mean mass-specific milk consumption (41 g·kg⁻¹) is substantially lower than in other otariid species (58–70 g·kg⁻¹) and, combined with a low mass gain efficiency (0.12 g·g⁻¹), contributes to the low mass-specific growth rates observed. There were no significant differences in either absolute or mass-specific milk consumption between the sexes. Significant differences, however, were found between the sexes in the body composition of pups with females generally having larger body lipid stores than males for any given mass. Peak milk yield by Australian fur seal females is estimated at 0.60 MJkg−0.75, substantially less than in Antarctic fur seals. The low level of maternal energy transfer in Australian fur seals may reflect the relatively low marine productivity of their foraging areas.

TOF-SIMS analysis using C60. Effect of impact energy on yield and damage

C₆₀ has been shown to give increased sputter yields and, hence, secondary ions when used as a primary particle in SIMS analysis. In addition, for many samples, there is also a reduction in damage accumulation following continued bombardment with the ion beam. In this paper, we report a study of the impact energy (up to 120 keV) of C₆₀ on the secondary ion yield from a number of samples with consideration of any variation in yield response over mass ranges up to m/z 2000. Although increased impact energy is expected to produce a corresponding increase in sputter yield/rate, it is important to investigate any increase in sample damage with increasing energy and, hence, efficiency of the ion beams. On our test samples including a metal, along with organic samples, there is a general increase in secondary ion yield of high-mass species with increasing impact energy. A corresponding reduction in the formation of low-mass fragments is also observed. Depth profiling of organic samples demonstrates that when using C₆₀, there does not appear to be any increase in damage evident in the mass spectra as the impact energy is increased.

Impact of carbon material on RF MEMS switch

Carbon materials such as Graphene and carbon nano tube promise a new generation of RF NEMS devices that bring many advantages due to their very high performances such as low mass, high Young's modulus and electrical conductivity. In this paper, the properties of Graphene for RF M/NEMS applications are briefly described. We compare the mechanical behaviour of Graphene switches with metallic RF MEMS switches such as Aluminium and Gold. The analytical study and simulation results show that the actuation voltage of Al and Au switches is high (35 V) whereas the actuation voltage for the Graphene switch is low (7.7 V). Also, the switching time of Graphene switch is 3.5 ns while the switching time for metallic switches is approximately 17μs.

Energy deficiency, menstrual disturbances, and low bone mass : what do exercising Australian women know about the female athlete triad?

Purpose: Prevention of the female athlete triad is essential to protect female athletes’ health. The aim of this study was to investigate the knowledge, attitudes, and behaviors of regularly exercising adult women in Australia toward eating patterns, menstrual cycles, and bone health.
Methods: A total of 191 female exercisers, age 18–40 yr, engaging in ≥2 hr/wk of strenuous activity, completed a survey. After 11 surveys were excluded (due to incomplete answers), the 180 participants were categorized into lean-build sports (n = 82; running/ athletics, triathlon, swimming, cycling, dancing, rowing), non-lean-build sports (n = 94; basketball, netball, soccer, hockey, volleyball, tennis, trampoline, squash, Australian football), or gym/fitness activities (n = 4).
Results: Mean (± SD) training volume was 9.0 ± 5.5 hr/wk, with participants competing from local up to international level. Only 10% of respondents could name the 3 components of the female athlete triad. Regardless of reported history of stress fracture, 45% of the respondents did not think that amenorrhea (absence of menses for ≥3 months) could affect bone health, and 22% of those involved in lean-build sports would do nothing if experiencing amenorrhea (vs. 3.2% in non-lean-build sports, p = .005). Lean-build sports, history of amenorrhea, and history of stress fracture were all significantly associated with not taking action in the presence of amenorrhea (all p < .005). Conclusions: Few active Australian women are aware of the detrimental effects of menstrual dysfunction on bone health. Education programs are needed to prevent the female athlete triad and ensure that appropriate actions are taken by athletes when experiencing amenorrhea.

Identification and disruption of the gene encoding the third member of the low-molecular-mass rhoptry complex in Plasmodium falciparum

The low-molecular-mass rhoptry complex of Plasmodium falciparum consists of three proteins, rhoptry-associated protein 1 (RAP1), RAP2, and RAP3. The genes encoding RAP1 and RAP2 are known; however, the RAP3 gene has not been identified. In this study we identify the RAP3 gene from the P. falciparum genome database and show that this protein is part of the low-molecular-mass rhoptry complex. Disruption of RAP3 demonstrated that it is not essential for merozoite invasion, probably because RAP2 can complement the loss of RAP3. RAP3 has homology with RAP2, and the genes are encoded on chromosome 5 in a head-to-tail fashion. Analysis of the genome databases has identified homologous genes in all Plasmodium spp., suggesting that this protein plays a role in merozoite invasion. The region surrounding the RAP3 homologue in the Plasmodium yoelii genome is syntenic with the same region in P. falciparum; however, there is a single gene. Phylogenetic comparison of the RAP2/3 protein family from Plasmodium spp. suggests that the RAP2/3 duplication occurred after divergence of these parasite species.

Purification and characterization of a low molecular mass alkaliphilic lipase of Bacillus cereus MTCC 8372

A low molecular mass alkaliphilic extra-cellular lipase of Bacillus cereus MTCC 8372 was purified 35-fold by hydrophobic interaction (Octyl-Sepharose) chromatography. The purified enzyme was found to be electrophoretically pure by denaturing gel electrophoresis and possessed a molecular mass of approximately 8 kDa. It is a homopentamer of 40 kDa as revealed by native-PAGE. The lipase was optimally active at 55 °C and retained approximately half of its original activity after 40 min incubation at 55 °C. The enzyme was maximally active at pH 8.5. Mg ²⁺ , Cu ²⁺ , Ca ²⁺ , Hg ²⁺ , Al ³⁺ and Fe ³⁺ at 1 mM enhanced hydrolytic activity of the lipase. Interestingly, Hg ²⁺ ions synergized and Zn ²⁺ and Co ²⁺ ions antagonized the lipase activity. Among surfactants, Tween 80 promoted the lipase activity. Phenyl methyl sulfonyl fluoride (PMSF, 15 mM) decreased 98% of original activity of lipase. The lipase was highly specific towards p -nitrophenyl palmitate and showed a V _max and K _m of 0.70 mmol.mg ⁻¹ .min ⁻¹ and 32 mM for hydrolysis of p NPP.

Osteopaenia - a marker of low bone mass and fracture risk

Areal bone mineral density is commonly categorised into normal bone mineral density, osteopaenia and osteoporosis on the basis of nominal thresholds recommended by the World Health Organization. However, bone mineral density is a continuous variable and there is a strong association between lower bone mineral density and greater risk for fracture. Fracture risk is not negligible in persons with moderate deficits in bone mineral density. Although absolute fracture risk is greatest for individuals with osteoporosis, more than half of the fractures arise from those with osteopaenia, and even normal bone mineral density, a probable consequence of greater numbers of individuals at risk in these categories. However, areal bone mineral density measurements used commonly in clinical practice do not detect differences in bone tissue properties, geometry and microarchitecture, which contribute to bone strength. Newer technologies such as high-resolution peripheral computed tomography have the advantage of assessing trabecular and cortical components of bone separately, in addition to geometric characteristics of the skeleton. Quantifying these parameters and considering clinical risk factors that affect fracture risk independent of bone quantity and quality, may better discriminate between high- and low-risk individuals. This would improve the decision-making for targeting appropriate interventions, either lifestyle or medication, to reduce thepublic health burden of fractures.

Low body mass and aerobic running fitness increase injury risk in elite Australian football

To assess the relationships between player characteristics (including age, playing experience, ethnicity, physical fitness) and in-season injury in elite Australian football.

What is the role of tobacco control advertising intensity and duration in reducing adolescent smoking prevalence? Findings from 16 years of tobacco control mass media advertising in Australia

ABSTRACT
Objective: To examine how the intensity and duration of tobacco control advertising relate to adolescent smoking prevalence.
Methods: Australian students (aged 12–17 years) participating in a national survey conducted triennially between 1993 and 2008 (sample size range 12 314–16 611). The outcome measure was students’ smoking in the previous 4 weeks collected through anonymous, self-completed surveys. For each student, monthly targeted rating points (TRPs, a measure of television advertising exposure) for tobacco control advertising was calculated for the 3 and 12 months prior to surveying. For each time period, cumulative TRPs exposure and exposure to three intensity levels (≥100 TRPs/month; ≥400 TRPs/month; ≥800 TRPs/month) over increasing durations (eg, 1 month, 2 months, etc) were calculated. Logistic regression examined associations between TRPs and adolescent smoking after controlling for demographic and policy variables.
Results: Past 3-month cumulative TRPs were found to have an inverse relationship with smoking prevalence. Low TRPs exposure in the past 12 months was positively associated with adolescent smoking prevalence. However, smoking prevalence reduced with cumulative exposure levels above 5800 cumulative TRPs. Additionally, exposure to ≥400 TRPs/month and ≥800 TRPs/month were associated with reduced likelihood of smoking, although the duration needed for this effect differed for the two intensity levels. When intensity was ≥400 TRPs/month, the odds of smoking only reduced with continuous exposure. When intensity was ≥800 TRPs/month, exposure at levels less than monthly was associated with reductions in smoking prevalence.
Conclusions: Both antismoking advertising intensity and duration are important for ensuring reductions in adolescent smoking prevalence.

Low lean tissue mass and physical performance as markers of sarcopenia in older men and women

Background: While declines in muscle mass and function occur in all individuals with advancing age, the extent and rate of decline vary in the general population. We aimed to determine the prevalence of low lean tissue mass combined with poor physical function as an indicator of sarcopenia among older men and women residing in southeastern Australia.

Methods: The study involved men and women aged 60+ years from the Geelong Osteoporosis Study (GOS). Skeletal muscle mass was measured as total lean tissue mass by dual energy x-ray absorptiometry (DXA) and expressed as a percentage of body weight to generate the skeletal mass index (SMI); low lean mass was defined as SMI T-score <-1. Low muscle function was based on performance using “timed up-and-go” scores >10s. Physical activity scores were determined using a validated questionnaire for the elderly and falls were self-reported for the previous year. Associations between sarcopenia, physical activity and falls were determined using multivariable regression techniques.

Results: Among 624 men, 233 had low SMI, 169 had low muscle performance and 81 had both, thus meeting criteria for sarcopenia. Among 436 women, 143 had low SMI, 179 had low muscle performance and 70 had both. A general age-related increase in the observed prevalence of sarcopenia appeared to be driven by an age-related increase in low performance. Sarcopenia was associated with lower physical activity scores. No association was detected between sarcopenia and falls for men but an association was observed for women (age-adjusted OR 1.87, 95% CI 1.11, 3.14).

Conclusion: In our population, the prevalence of sarcopenia was 10.6% (95% CI 7.7, 13.4) for men and 14.5% (95% CI 10.8, 18.3) for women. Men and women with sarcopenia were habitually less active and, for women, sarcopenia was associated with increased likelihood of falls.

Which aspects of socioeconomic status are related to obesity among men and women?

OBJECTIVE: This study aimed to investigate the relationships between body weight and fat distribution, and four empirically derived domains of socioeconomic status: employment, housing, migration status and family unit.

DESIGN: A population-based study was used.

PARTICIPANTS: A total of 8667 randomly-selected adults (4167 men; 4500 women) who participated in the 1995 Australian National Health and Nutrition Surveys provided data on a range of health factors including objective height, weight and body fat distribution, and a range of sociodemographic indicators.

RESULTS: Results demonstrated associations for women, after controlling for age, between the employment domain, and body mass index and waist-to-hip ratio. Low status employed women were 1.4 times as likely to be overweight as high status employed women. There were less consistent relationships observed among these factors for men. Relationships between family unit and indicators of body weight and body fat distribution were observed for both men and women, with those who were married, particularly men (OR=1.6, 95% CI 1.4-2.0), at higher risk of overweight. The migration and housing socioeconomic status domains were not consistently associated with body mass index or waist-to-hip ratio.

CONCLUSIONS: These findings indicate that different components of socioeconomic status may be important in predicting obesity, and thus should be examined separately. Future research would benefit from investigating the underlying mechanisms governing the relationships between socioeconomic status domains further, particularly those related to employment and family unit and obesity

Whose socioeconomic status influences a women's obesity risk: her mother's, her father's, or her own?

Background Evidence on the relative influence of childhood vs adulthood socioeconomic conditions on obesity risk is limited and equivocal. The objective of this study was to investigate associations of several indicators of mothers', fathers', and own socioeconomic status, and intergenerational social mobility, with body mass index (BMI) and weight change in young women.

Methods This population-based cohort study used survey data provided by 8756 women in the young cohort (aged 18–23 years at baseline) of the Australian Longitudinal Study on Women's Health. In 1996 and 2000, women completed mailed surveys in which they reported their height and weight, and their own, mother's, and father's education and occupation.

Results Multiple linear regression models showed that both childhood and adulthood socioeconomic status were associated with women's BMI and weight change, generally in the hypothesized (inverse) direction, but the associations varied according to socioeconomic status and weight indicator. Social mobility was associated with BMI (based on father's socioeconomic status) and weight change (based on mother's socioeconomic status), but results were slightly less consistent.

Conclusions Results suggest lasting effects of childhood socioeconomic status on young women's weight status, independent of adult socioeconomic status, although the effect may be attenuated among those who are upwardly socially mobile. While the mechanisms underlying these associations require further investigation, public health strategies aimed at preventing obesity may need to target families of low socioeconomic status early in children's lives.

Body mass index and parent-reported self-estem in elementary school children: evidence for a causal relationship.

OBJECTIVE: To clarify relationships between body mass index (BMI) and self-esteem in young children at a population level. To assess whether low self-esteem precedes or follows development of overweight/obesity in children. DESIGN: Prospective cohort study in elementary schools throughout Victoria, Australia. Child BMI and self-esteem were measured in 1997 and 2000. SUBJECTS: Random sample of 1,157 children who were in the first 4 y of elementary school (aged 5-10 y) at baseline. MEASURES: BMI was calculated from measured height and weight, then transformed to z-scores. Children were classified as nonoverweight, overweight or obese based on international cut-points. Low child self-esteem was defined as a score below the 15th percentile on the self-esteem subscale of the parent-reported Child Health Questionnaire. RESULTS: Overweight/obese children had lower median self-esteem scores than nonoverweight children at both timepoints, especially at follow-up. After accounting for baseline self-esteem, higher baseline BMI z-score predicted poorer self-esteem at follow-up (P=0.008). After accounting for baseline BMI z-score, poorer baseline self-esteem did not predict higher BMI z-score at follow-up. While nonoverweight children with low baseline self-esteem were more likely to develop overweight/obesity (OR=2.1, 95% CI=1.2, 3.6), this accounted for only a small proportion of the incidence of overweight. CONCLUSIONS: Our data show an increasingly strong association between lower self-esteem and higher body mass across the elementary school years. Overweight/obesity precedes low self-esteem in many children, suggesting a causal relationship. This indicates that prevention and management strategies for childhood overweight/obesity need to begin early to minimise the impact on self-esteem.

Evolution of egg size and fertilisation efficiency in sea stars: large eggs are not fertilised more readily than small eggs in Patiriella (Echinodermata: Asteroidea)

Fertilisation kinetics theory suggests that, when sperm are limiting, the larger eggs of broadcast-spawning marine organisms ought to be fertilised more frequently than smaller eggs, because they provide a bigger target for searching sperm. Whilst this effect has been demonstrated within species, it is not known if this pattern holds among species. We tested whether a large difference in egg size between congeneric seastars with contrasting planktotrophic and lecithotrophic modes of development results in differences in the likelihood of eggs being fertilised in sperm-limiting situations. Measurement of egg sizes and sperm swimming speeds led to the prediction that the sperm–egg collision rate constant for Patiriella calcar (420-µm-diameter egg) should be nine times greater than for P. regularis (140-µm-diameter egg). Although the eggs of P. calcar should be fertilised at greater rates in low sperm concentrations, they were not. When gametes were allowed to mix for 10 s, the hypothesis that P. calcar eggs required less sperm than P. regularis to ensure 50% of eggs were fertilised was rejected. When gametes were mixed for 5 min, P. regularis eggs were more frequently fertilised, but the difference was not statistically significant. We conclude there must be a difference between these species in the likelihood that when a sperm finds a conspecific egg it can successfully fertilise. This apparent uncoupling of egg size and likelihood of fertilisation suggests that fertilisation is not a major constraint on the evolution of egg size in these seastars.