Showing papers by "Deakin University published in 2007"

Twinning and the ductility of magnesium alloys Part I: “Tension” twins

Abstract: Magnesium and its alloys do not in general undergo the same extended range of plasticity as their competitor structural metals. The present work is part I of a study that examines some of the roles deformation twinning might play in the phenomenon. A series of tensile test results are reported for the common wrought alloy AZ31. These data are employed in conjunction with a simple constitutive model to argue that View the MathML source twinning (which gives extension along the c-axis) can increase the uniform elongation in tensile tests. This effect appears to be similar to that seen in Ti, Zr and Cu–Si and in the so called TWIP phenomenon in steel.

Automatic Age Estimation Based on Facial Aging Patterns

Abstract: While recognition of most facial variations, such as identity, expression, and gender, has been extensively studied, automatic age estimation has rarely been explored. In contrast to other facial variations, aging variation presents several unique characteristics which make age estimation a challenging task. This paper proposes an automatic age estimation method named AGES (AGing pattErn Subspace). The basic idea is to model the aging pattern, which is defined as the sequence of a particular individual's face images sorted in time order, by constructing a representative subspace. The proper aging pattern for a previously unseen face image is determined by the projection in the subspace that can reconstruct the face image with minimum reconstruction error, while the position of the face image in that aging pattern will then indicate its age. In the experiments, AGES and its variants are compared with the limited existing age estimation methods (WAS and AAS) and some well-established classification methods (kNN, BP, C4.5, and SVM). Moreover, a comparison with human perception ability on age is conducted. It is interesting to note that the performance of AGES is not only significantly better than that of all the other algorithms, but also comparable to that of the human observers.

Twinning and the ductility of magnesium alloys: Part II. “Contraction” twins

Abstract: Magnesium and its alloys do not in general undergo the same extended range of plasticity as their competitor structural metals. The present work presents part II of a study that examines some of the roles deformation twinning might play in the phenomenon. A series of tensile and compression tests results are reported for common wrought alloys: AZ31, ZK60 and ZM20. These data are combined with EBSD analysis and simple flow stress models to argue the following: (i) that “contraction” double twinning (which enables contraction along the c axis) can decrease the uniform elongation, and (ii) that compression double twinning can also account for shear failure at low strains. The last of these is described as a combined consequence of strain softening of the continuum and the local generation of twin sized voids.

Chemerin is a novel adipokine associated with obesity and metabolic syndrome.

Abstract: Soluble protein hormones are key regulators of a number of metabolic processes, including food intake and insulin sensitivity. We have used a signal sequence trap to identify genes that encode secreted or membrane-bound proteins in Psammomys obesus, an animal model of obesity and type 2 diabetes (T2D). Using this signal sequence trap, we identified the chemokine chemerin as being a novel adipokine. Gene expression of chemerin and its receptor, chemokine-like receptor 1 (CMKLR1), was significantly higher in adipose tissue of obese and type 2 diabetic P. obesus compared with lean, normoglycemic P. obesus. Fractionation of P. obesus adipose tissue confirmed that chemerin was predominantly expressed in adipocytes, whereas CMKLR1 was expressed in both adipocytes and stromal-vascular cells of adipose tissue. In 3T3-L1 adipocytes, chemerin was markedly induced during differentiation, whereas CMKLR1 was down-regulated during differentiation. Serum chemerin levels were measured by ELISA in human plasma samples from 114 subjects with T2D and 142 normal glucose tolerant controls. Plasma chemerin levels were not significantly different between subjects with T2D and normal controls. However, in normal glucose tolerant subjects, plasma chemerin levels were significantly associated with body mass index, circulating triglycerides, and blood pressure. Here we report, for the first time, that chemerin is an adipokine, and circulating levels of chemerin are associated with several key aspects of metabolic syndrome.

Increased consumption of fruit and vegetables is related to a reduced risk of coronary heart disease: meta-analysis of cohort studies

Abstract: Increased consumption of fruit and vegetables has been shown to be associated with a reduced risk of coronary heart disease (CHD) in many epidemiological studies, however, the extent of the association is uncertain. We quantitatively assessed the relation between fruit and vegetable intake and incidence of CHD by carrying out a meta-analysis of cohort studies. Studies were included if they reported relative risks (RRs) and corresponding 95% confidence interval (CI) of CHD with respect to frequency of fruit and vegetable intake. Twelve studies, consisting of 13 independent cohorts, met the inclusion criteria. There were 278,459 individuals (9143 CHD events) with a median follow-up of 11 years. Compared with individuals who had less than 3 servings/day of fruit and vegetables, the pooled RR of CHD was 0.93 (95% CI: 0.86-1.00, P=0.06) for those with 3-5 servings/day and 0.83 (0.77-0.89, P<0.0001) for those with more than 5 servings/day. Subgroup analyses showed that both fruits and vegetables had a significant protective effect on CHD. Our meta-analysis of prospective cohort studies demonstrates that increased consumption of fruit and vegetables from less than 3 to more than 5 servings/day is related to a 17% reduction in CHD risk, whereas increased intake to 3-5 servings/day is associated with a smaller and borderline significant reduction in CHD risk. These results provide strong support for the recommendations to consume more than 5 servings/day of fruit and vegetables.

A checklist for ecological management of landscapes for conservation

Abstract: The management of landscapes for biological conservation and ecologically sustainable natural resource use are crucial global issues. Research for over two decades has resulted in a large literature, yet there is little consensus on the applicability or even the existence of general principles or broad considerations that could guide landscape conservation. We assess six major themes in the ecology and conservation of landscapes. We identify 13 important issues that need to be considered in developing approaches to landscape conservation. They include recognizing the importance of landscape mosaics (including the integration of terrestrial and aquatic areas), recognizing interactions between vegetation cover and vegetation configuration, using an appropriate landscape conceptual model, maintaining the capacity to recover from disturbance and managing landscapes in an adaptive framework. These considerations are influenced by landscape context, species assemblages and management goals and do not translate directly into on-the-ground management guidelines but they should be recognized by researchers and resource managers when developing guidelines for specific cases. Two crucial overarching issues are: (i) a clearly articulated vision for landscape conservation and (ii) quantifiable objectives that offer unambiguous signposts for measuring progress.

Objectively measured light- intensity physical activity is independently associated with 2-h plasma glucose

Abstract: Objective : We examined the associations of objectively measured sedentary time, light-intensity physical activity, and moderate- to vigorous-intensity activity with fasting and 2-h postchallenge plasma glucose in Australian adults. Research Design and Methods : A total of 67 men and 106 women (mean age ± SD 53.3 ± 11.9 years) without diagnosed diabetes were recruited from the 2004–2005 Australian Diabetes, Obesity, and Lifestyle (AusDiab) study. Physical activity was measured by Actigraph accelerometers worn during waking hours for 7 consecutive days and summarized as sedentary time (accelerometer counts/min Results : After adjustment for confounders (including waist circumference), sedentary time was positively associated with 2-h plasma glucose ( b = 0.29, 95% CI 0.11–0.48, P = 0.002); light-intensity activity time ( b = –0.25, –0.45 to –0.06, P = 0.012) and moderate- to vigorous-intensity activity time ( b = –1.07, –1.77 to –0.37, P = 0.003) were negatively associated. Light-intensity activity remained significantly associated with 2-h plasma glucose following further adjustment for moderate- to vigorous-intensity activity ( b = –0.22, –0.42 to –0.03, P = 0.023). Associations of all activity measures with fasting plasma glucose were nonsignificant ( P > 0.05). Conclusions : These data provide the first objective evidence that light-intensity physical activity is beneficially associated with blood glucose and that sedentary time is unfavorably associated with blood glucose. These objective data support previous findings from studies using self-report measures, and suggest that substituting light-intensity activity for television viewing or other sedentary time may be a practical and achievable preventive strategy to reduce the risk of type 2 diabetes and cardiovascular disease.

Promoting Physical Activity Participation among Children and Adolescents

Abstract: With global increases in the prevalence of overweight and obesity among children and adolescents, there has never been a more urgent need for effective physical activity programs. The aim of this narrative review is to summarize the evidence of the effectiveness of interventions that report physical activity outcomes in children aged 4-12 years and adolescents aged 13-19 years. A systematic search of electronic databases identified 76 interventions. Most interventions were delivered via the school setting (57 interventions), nine through the family setting, six via primary care, and four in community- or Internet-based settings. Children's physical activity interventions that were most effective in the school setting included some focus on physical education, activity breaks, and family strategies. Interventions delivered in the family setting were not highly effective, but many were pilot studies. The use of motivationally tailored strategies and program delivery in the primary care setting showed promise among adolescents. Many studies had methodological and reporting flaws (e.g., no baseline data, poor study design, physical activity measures of unknown reliability and validity, and poor reporting of sample size, response rates, attrition/retention, compliance, year of intervention, and duration of intervention). Publications reporting the results of evaluations of intervention studies should follow the Consolidated Standards of Reporting Trials guidelines or, for nonrandomized studies, should follow the Transparent Reporting of Evaluations with Nonrandomized Designs guidelines. Further evidence of the effectiveness of interventions promoting young people's physical activity in family and community settings is needed.

Associations Between the Home Food Environment and Obesity‐promoting Eating Behaviors in Adolescence

Abstract: Objective: This study examines relationships between multiple aspects of the home food environment and obesity-promoting characteristics of 12- to 13-year-old adolescents' diets, specifically frequency of consumption of high-energy fluids, sweet snacks, savory snacks, and take-out foods. Research Methods: This was a cross-sectional study including 347 adolescents 12 to 13 years of age and their parents. Data were collected via self-completed surveys. The adolescents' diets were assessed using a Food Frequency Questionnaire derived from existing age-appropriate National Nutrition Survey data. An extensive range of domains within the home food environment were assessed. Bivariate linear regression analyses were run split by gender. Forced entry multiple linear regression analyses (adjusting for all variables significant in bivariate analyses as well as for maternal education) were also performed, stratified by the sex of the child. Results: The influence of mothers, either as models for eating behaviors or as the providers of food, was pervasive. Mothers' intake of high-energy fluids (p = 0.003), sweet snacks (p = 0.010), savory snacks (p = 0.008), and take-out food (p = 0.007) was positively associated with boys' intake of all these foods. In addition, mothers' intake of high-energy fluids was positively associated with daughters' consumption of these drinks (p = 0.025). Furthermore, availability of unhealthy foods at home was positively associated with girls' sweet snack (p = 0.001), girls' savory snack (p Discussion: This study of home food environment influences on adolescent diet highlights the pervasive influence of mothers in determining adolescents' obesity-promoting eating, providing direction for obesity prevention strategies and future research.

Wastewater irrigation: The state of play

Abstract: As demand for fresh water intensifies, wastewater is frequently being seen as a valuable resource. Furthermore, wise reuse of wastewater alleviates concerns attendant with its discharge to the environment. Globally, around 20 million ha of land are irrigated with wastewater, and this is likely to increase markedly during the next few decades as water stress intensifies. In 1995, around 2.3 billion people lived in water-stressed river basins and this could increase to 3.5 billion by 2025. We review the current status of wastewater irrigation by providing an overview of the extent of the practice throughout the world and through synthesizing the current understanding of factors influencing sustainable wastewater irrigation. A theme that emerges is that wastewater irrigation is not only more common in water-stressed regions such as the Near East, but the rationale for the practice also tends to differ between the developing and developed worlds. In developing nations, the prime drivers are livelihood dependence and food security, whereas environmental agendas appear to hold greater sway in the developed world. The following were identified as areas requiring greater understanding for the long-term sustainability of wastewater irrigation: (i) accumulation of bioavailable forms of heavy metals in soils, (ii) environmental fate of organics in wastewater-irrigated soils, (iii) influence of reuse schemes on catchment hydrology, including transport of salt loads, (iv) risk models for helminth infections (pertinent to developing nations), (v) microbiological contamination risks for aquifers and surface waters, (vi) transfer efficiencies of chemical contaminants from soil to plants, (vii) health effects of chronic exposure to chemical contaminants, and (viii) strategies for engaging the public.

Dynamic recrystallization in AZ31 magnesium alloy

Abstract: The effects of temperature and strain rate, as the most important thermomechanical processing (TMP) parameters, on the microstructural evolution of AZ31 magnesium alloy were studied. This was performed applying hot compression tests at a temperature range of 250–450 °C with various strain rates. The results indicated that the amount and the size of dynamically recrystallized grains are increased as Zener–Hollomon parameter decreased. In addition, the evolution of dynamically recrystallized grains was examined with increasing strain. In general, the amount of dynamically recrystallized grain is observed to increase with strain in a sigmoidal form. However, the related grain size was remained constant as strain increased.

The development and evaluation of a measure to assess cancer survivors' unmet supportive care needs: the CaSUN (Cancer Survivors' Unmet Needs measure)

Abstract: Background: Many cancer survivors experience ongoing morbidity over the survivorship continuum and their supportive care needs have yet to be comprehensively assessed. Methods: This study aimed to develop and empirically evaluate a self-report measure of cancer survivors' supportive care needs. In Phase I, questionnaire items were generated based upon previous qualitative research that identified both unique and shared needs in survivors and their partners; items were constructed into the Cancer Survivors' Unmet Needs measure (CaSUN). In Phase 2, the CaSUN was completed by 353 cancer survivors who had been diagnosed with cancer between 1 and 15 years earlier and were currently disease-free. Results: After modification, the CaSUN included 35 unmet need items, 6 positive change items and an open-ended question. Good acceptability, internal consistency and validity were demonstrated, although test–retest reliability was low. Maximum likelihood factor analysis identified five discrete factors: Existential Survivorship, Comprehensive Care, Information, Quality of Life and Relationships. Conclusions: Preliminary data indicates that the CaSUN meets the majority of psychometric criteria for assessment measures, although its low test–retest reliability awaits further investigation. The CaSUN will facilitate the evaluation of supportive care services and generation of service delivery recommendations for cancer survivors. Copyright © 2006 John Wiley & Sons, Ltd.

Subjective Wellbeing as an Affective-Cognitive Construct

Abstract: The affective content of Subjective Wellbeing (SWB) was investigated in two separate studies. Study 1 involved a representative sample of 478 participants from across Australia aged between 18 and 72 years. This study tested the circumplex model of affect and then determined the minimum set of affects that explain variance in SWB. The model was supported, with most affects congregated around the valence axis. Overall, 64% of the variance in SWB was explained by six Core Affects, indicating that SWB is a highly affective construct. Study 2 tested the relative strength of Core Affect (content, happy and excited), in three separate models of SWB incorporating cognition (seven discrepancies) and all five factors of personality. Using a sample of 854 participants aged been 18–86 years, structural equation modeling was used to compare an affective-cognitive driven model of SWB, with a personality driven model of SWB and a discrepancy driven model of SWB. The results provide support for an affective-cognitive model which explained 90 percent of the variance in SWB. All models confirm that the relationship between SWB, Core Affect and Discrepancies is far stronger than the relationship between personality and SWB. It is proposed that Core Affect and Discrepancies comprise the essence of SWB. Moreover, Core Affect is the driving force behind individual set-point levels in SWB homeostasis.

Examination of environmental beliefs and its impact on the influence of price, quality and demographic characteristics with respect to green purchase intention

Abstract: Research indicates that the environment has had a definite impact on consumer behaviour whereby suggesting to target consumers according to their environmental beliefs. This study investigated the consumers' green purchase behaviour using price and quality attributes as contributors to the formation of purchase intention. It attempts to construct a model that may facilitate the better understanding of green consumers' market segments through the use of an intelligent soft computing model. The model is designed to incorporate knowledge, beliefs, demographic profiles and situational variables. This potentially provides a more direct method for companies to gauge consumers' intention to purchase green products. The results showed strong preference for companies to place higher priority on reducing pollution than on increasing profitability. It highlighted different clusters that demonstrate various levels of the strength of intention to purchase and market segment profiles.

Strategies which aim to positively impact on weight, physical activity, diet and sedentary behaviours in children from zero to five years. A systematic review of the literature

Abstract: Preventing the development of obesity in children is an international health priority. To assess the effectiveness of interventions designed to prevent obesity, promote healthy eating and/or physical activity and/or to reduce sedentary behaviours in 0-5-year-old children, a systematic review of the literature was performed. Literature searches were limited to articles published between January 1995 and June 2006, printed in English and sampling children aged 0-5-years. Searches excluded literature concerned with breastfeeding, eating disorders, and interventions which were school-based or concerned with obesity treatment. Two reviewers independently extracted data and assessed study strengths and weaknesses. Nine included studies were grouped based on the settings in which they were delivered. Most studies involved multi-approach interventions, were conducted in the USA and varied in study designs and quality. All showed some level of effectiveness on at least one obesity-behaviour in young children. These studies support, at a range of levels, the premise that parents are receptive to and capable of some behavioural changes that may promote healthy weight in their young children. The small quantity of research heralds the need, particularly given the potential for early intervention to have long-lasting impacts on individual and population health, to build in a substantial way upon this evidence base.

Suppression by ABA of salicylic acid and lignin accumulation and the expression of multiple genes, in Arabidopsis infected with Pseudomonas syringae pv. tomato

Abstract: Abscisic acid (ABA) has been implicated in determining the outcome of interactions between many plants and their pathogens. We had previously shown that increased concentrations of ABA within leaves of Arabidopsis induced susceptibility towards an avirulent strain of Pseudomonas syringae pathovar (pv.) tomato. We now show that ABA induces susceptibility via suppression of the accumulation of components crucial for a resistance response. Lignin and salicylic acid concentrations in leaves were increased during a resistant interaction but reduced when plants were treated with ABA. The reduction in lignin and salicylic acid production was independent of the development of the hypersensitive response (HR), indicating that, in this host-pathogen system, HR is not required for resistance. Genome-wide gene expression analysis using microarrays showed that treatment with ABA suppressed the expression of many defence-related genes, including those important for phenylpropanoid biosynthesis and those encoding resistance-related proteins. Together, these results show that resistance induction in Arabidopsis to an avirulent strain of P. syringae pv. tomato is regulated by ABA.

Personal, social and environmental determinants of educational inequalities in walking: a multilevel study.

Abstract: Objective: To investigate the contribution of personal, social and environmental factors to mediating socioeconomic (educational) inequalities in women’s leisure-time walking and walking for transport. Methods: A community sample of 1282 women provided survey data on walking for leisure and transport; educational level; enjoyment of, and self-efficacy for, walking; physical activity barriers and intentions; social support for physical activity; sporting/recreational club membership; dog ownership; and perceived environmental aesthetics and safety. These data were linked with objective environmental data on the density of public open space and walking tracks in the women’s local neighbourhood, coastal proximity and street connectivity. Results: Multilevel modelling showed that different personal, social and environmental factors were associated with walking for leisure and walking for transport. Variables from all three domains explained (mediated) educational inequalities in leisure-time walking, including neighbourhood walking tracks; coastal proximity; friends’ social support; dog ownership; self-efficacy, enjoyment and intentions. On the other hand, few of the variables examined explained educational variations in walking for transport, exceptions being neighbourhood, coastal proximity, street connectivity and social support from family. Conclusions: Public health initiatives aimed at promoting, and reducing educational inequalities in, leisure-time walking should incorporate a focus on environmental strategies, such as advocating for neighbourhood walking tracks, as well as personal and social factors. Further investigation is required to better understand the pathways by which education might influence walking for transport.