Animated feather coats using field lines

The tedious task of manually placing feathers on computer animated objects involves aligning feathers, ensuring that they do not insect each other or penetrate the surface, deforming every feather to match the local surface features, and ensuring that the feather coat is consistent when the underlying object is animated.

We present a technique for generating a feather coat over an object. Feather orientation is specified quickly and easily, feathers are deformed while ensuring collision prevention, and the coat can be animated. We create a vector field in the space surrounding the body object and deform feathers to align with the field lines. The non-intersection property of the field lines ensures that feather intersections are avoided. We provide a formulation of a suitable vector field and demonstrate that it is capable of producing realistic feather coats. The process can easily be integrated into the work-flow of standard modelling and animation processes.

We show examples of feather coat creation on a range of objects, proving that field line based placement of feather coats provides the desired functionality for feather modelling and animation.

Involvement of young Australian adults in meal preparation : cross-sectional associations with abdominal obesity and body mass index

Previous research has shown that involvement in meal preparation is positively associated with better diet quality. However, it is unclear whether there is an association between involvement in meal preparation and being overweight or obese. This study investigated whether the level of involvement in meal preparation was associated with objectively measured weight status in young adults. During 2004-2006, a national sample of 1,996 Australian adults aged 26 to 36 years completed a self-administered questionnaire including questions on sociodemographic characteristics, diet, and physical activity. Participants were asked to report who usually prepared the main meal on working days and responses were categorized as “myself,” “shared,” or “someone else.” Waist circumference, weight, and height were measured by trained staff. Moderate abdominal obesity was defined as waist circumference >94 cm for men and >80 cm for women. Overweight was defined as body mass index (calculated as kg/m2) >25. Prevalence ratios were calculated using log binomial regression. After adjusting for age, education, and leisure time physical activity, men who shared the meal preparation had a slightly lower prevalence of moderate abdominal obesity (prevalence ratio=0.92; 95% confidence interval [CI]: 0.86 to 0.99) than those whose meals were usually prepared by someone else. There was no association with having sole responsibility (prevalence ratio=0.99; 95% CI: 0.92 to 1.06). There were no associations between level of involvement in meal preparation and being overweight (shared responsibility prevalence ratio=0.99; 95% CI: 0.92 to 1.07; sole responsibility prevalence ratio=0.98; 95% CI: 0.91 to 1.05). For women, level of involvement was not associated with moderate abdominal obesity (shared responsibility prevalence ratio=0.93; 95% CI: 0.84 to 1.03; sole responsibility prevalence ratio=0.94; 95% CI: 0.86 to 1.03) or being overweight (shared responsibility prevalence ratio=0.93; 95% CI: 0.84 to 1.02; sole responsibility prevalence ratio=0.93; 95% CI: 0.85 to 1.02). In this sample of young adults, level of involvement in meal preparation was not strongly related to weight status.

Maternal and best friends' influences on meal-skipping behaviours

Skipping meals is particularly common during adolescence and can have a detrimental effect on multiple aspects of adolescent health. Understanding the correlates of meal-skipping behaviours is important for the design of nutrition interventions. The present study examined maternal and best friends’ influences on adolescent meal-skipping behaviours. Frequency of skipping breakfast, lunch and dinner was assessed using a Web-based survey completed by 3001 adolescent boys and girls from years 7 and 9 of secondary schools in Victoria, Australia. Perceived best friend and maternal meal skipping, modelling of healthy eating (eating healthy food, limiting junk food, eating fruit and vegetables) and weight watching were assessed. Best friend and maternal factors were differentially associated with meal-skipping behaviours. For example, boys and girls who perceived that their best friend often skipped meals were more likely to skip lunch (OR ¼ 2·01, 95% CI 1·33, 3·04 and OR ¼ 1·93, 95% CI 1·41, 2·65; P,0·001). Boys and girls who perceived that their mother often skipped meals were more likely to skip breakfast (OR ¼ 1·48, 95% CI 1·01, 2·15; P,0·05 and OR ¼ 1·93, 95% CI 1·42, 2·59; P,0·001) and lunch (OR ¼ 2·05, 95% CI 1·35, 3·12 and OR ¼ 2·02, 95% CI 1·43, 2·86; P,0·001). Educating adolescents on how to assess and interpret unhealthy eating behaviours that they observe from significant others may be one nutrition promotion strategy to reduce meal-skipping behaviour. The involvement of mothers may be particularly important in such efforts. Encouraging a peer subculture that promotes regular consumption of meals and educates adolescents on the detrimental impact of meal-skipping behaviour on health may also offer a promising nutrition promotion strategy.

Classification of main meal patterns - a latent class approach

Relatively little examination of the meals that are prepared in households has been conducted, despite their well-defined properties and widespread community interest in their preparation. The purpose of the present study was to identify the patterns of main meal preparation among Australian adult household meal preparers aged 44 years and younger and 45 years and over, and the relationships between these patterns and likely socio-demographic and psychological predictors. An online cross-sectional survey was conducted by Meat and Livestock Australia among a representative sample of people aged 18–65 years in Australia in 2011. A total of 1076 usable questionnaires were obtained, which included categorical information about the main meal dishes that participants had prepared during the previous 6 months along with demographic information, the presence or absence of children at home, confidence in seasonal food knowledge and personal values. Latent class analysis was applied and four types of usage patterns of thirty-three popular dishes were identified for both age groups, namely, high variety, moderate variety, high protein but low beef and low variety. The meal patterns were associated differentially with the covariates between the age groups. For example, younger women were more likely to prepare a high or moderate variety of meals than younger men, while younger people who had higher levels of education were more likely to prepare high-protein but low-beef meals. Moreover, young respondents with higher BMI were less likely to prepare meals with high protein but low beef content. Among the older age group, married people were more likely to prepare a high or moderate variety of meals than people without partners. Older people who held strong universalist values were more likely to prepare a wide variety of meals with high protein but low beef content. For both age groups, people who had children living at home and those with better seasonal food knowledge were more likely to prepare a high variety of dishes. The identification of classes of meal users would enable health communication to be tailored to improve meal patterns. Moreover, the concept of meals may be useful for health promotion, because people may find it easier to change their consumption of meals rather than individual foods.

Dietary sources and meal distribution of sodium and potassium in a sample of Australian adults

Aim
Reducing dietary sodium and increasing dietary potassium are recommended to reduce blood pressure. This study aimed to determine the main foods sources of sodium and potassium.

Methods
Participants were recruited via advertisements or blood pressure screening sessions. Food sources of sodium and potassium were assessed via 24-hour dietary records in 299 free-living Australian adults (141 male, 158 female; age 54.6(9.5)years; BMI 29.4(3.9)kg/m2).

Results
The mean sodium intake was 118(51)mmol/d (2725(1176)mg/d) and the mean potassium intake was 91(28)mmol/d (3550(1098)mg/d). Breads and cereals provided the majority (38%) of sodium with bread contributing 20%. Vegetable products/dishes contributed most potassium (23%) with potatoes providing 9%. Main meals provided 89% of sodium and 85% of potassium. Lunch and dinner provided similar sodium proportions (34% and 38%, respectively) but more energy was consumed at dinner (26% vs 40%, respectively). Lunch had the highest sodium density of all meals (420 mg/MJ).

Conclusion
A reduction in the salt content of processed foods, particularly bread, is recommended to decrease sodium intake. This reduction in salt content combined with meal specific education focusing on choosing lower sodium foods at lunch in particular, as well as incorporating more fruits and vegetables, could effectively reduce dietary sodium and increase potassium.

Crews, wusses, and whoppas: core and fringe vocabularies of Australian meal-break conversations in the workplace

Conversational samples were collected from 34 nondisabled subjects across four worksites. The total sample was analyzed for core vocabulary, and the five most frequently referenced topics were analyzed for core and fringe vocabularies and the commonality of fringe vocabulary across topics. The results indicated that there was a small stable core vocabulary of 347 words containing words unique to this study, which accounted for 78% of the conversational sample. A total of 21 words in the fringe vocabulary was common to all topics. Implications of this study for vocabulary selection for augmented communicators in employment are discussed.

Topics of meal-break conversations

Meal-break conversational samples were collected from 34 nondisabled participants across four worksites. The samples were analyzed for topics referenced and also for patterns of topics associated with days of the week. The results of the analysis indicated that the participants referenced 73 different topics. Analysis of the 10 most frequently referenced topics in each composite day file revealed 19 topics, of which 5 (i.e., work, fact finding, judgments, food, and family life) were referenced every day. Analysis of the number of communication segments in each of the 19 topics indicated that fact finding was the most frequently referenced topic, but work was the largest topic (i.e., contained the greatest number of words). There was some pattern to topic reference associated with the day of the week. Implications of this information for individuals with severe communication impairments who wish to access the work force are discussed.

Effects of ingesting low glycemic index carbohydrate food for the sahur meal on subjective, metabolic and physiological responses, and endurance performance in Ramadan fasted men

To investigate the effect of low glycemic index (LGI) carbohydrate meal on subjective, metabolic and physiological responses, and endurance performance in the Ramadan fasted state.

Phylogenetic analysis of beak and feather disease virus across a host ring-species complex

Pathogens have been hypothesized to play a major role in host diversity and speciation. Susceptibility of hybrid hosts to pathogens is thought to be a common phenomenon that could promote host population divergence and subsequently speciation. However, few studies have tested for pathogen infection across animal hybrid zones while testing for codivergence of the pathogens in the hybridizing host complex. Over 8 y, we studied natural infection by a rapidly evolving single-strand DNA virus, beak and feather diseases virus (BFDV), which infects parrots, exploiting a host-ring species complex (Platycercus elegans) in Australia. We found that host subspecies and their hybrids varied strikingly in both BFDV prevalence and load: both hybrid and phenotypically intermediate subspecies had lower prevalence and load compared with parental subspecies, while controlling for host age, sex, longitude and latitude, as well as temporal effects. We sequenced viral isolates throughout the range, which revealed patterns of genomic variation analogous to Mayr's ring-species hypothesis, to our knowledge for the first time in any host-pathogen system. Viral phylogeny, geographic location, intraspecific host density, and parrot community diversity and composition did not explain the differences in BFDV prevalence or load between subpopulations. Overall, our analyses suggest that functional host responses to infection, or force of infection, differ between subspecies and hybrids. Our findings highlight the role of host hybridization and clines in altering host-pathogen interactions, dynamics that can have important implications for models of speciation with gene flow, and offer insights into how pathogens may adapt to diverging host populations.

Understanding meal patterns: definitions, methodology and impact on nutrient intake and diet quality

Traditionally, nutrition research has focused on individual nutrients, and more recently dietary patterns. However, there has been relatively little focus on dietary intake at the level of a 'meal'. The purpose of the present paper was to review the literature on adults' meal patterns, including how meal patterns have previously been defined and their associations with nutrient intakes and diet quality. For this narrative literature review, a comprehensive search of electronic databases was undertaken to identify studies in adults aged ≥  19 years that have investigated meal patterns and their association with nutrient intakes and/or diet quality. To date, different approaches have been used to define meals with little investigation of how these definitions influence the characterisation of meal patterns. This review identified thirty-four and fourteen studies that have examined associations between adults' meals patterns, nutrient intakes and diet quality, respectively. Most studies defined meals using a participant-identified approach, but varied in the additional criteria used to determine individual meals, snacks and/or eating occasions. Studies also varied in the types of meal patterns, nutrients and diet quality indicators examined. The most consistent finding was an inverse association between skipping breakfast and diet quality. No consistent association was found for other meal patterns, and little research has examined how meal timing is associated with diet quality. In conclusion, an understanding of the influence of different meal definitions on the characterisation of meal patterns will facilitate the interpretation of the existing literature, and may provide guidance on the most appropriate definitions to use.

Prevalence of beak and feather disease virus in wild Platycercus elegans: comparison of three tissue types using a probe-based real-time qPCR test

The detection of avian viruses in wild populations has considerable conservation implications. For DNA-based studies, feathers may be a convenient sample type for virus screening and are, therefore, an increasingly common technique. This is despite recent concerns about DNA quality, ethics, and a paucity of data comparing the reliability and sensitivity of feather sampling to other common sample types such as blood. Alternatively, skeletal muscle tissue may offer a convenient sample to collect from dead birds, which may reveal viraemia. Here, we describe a probe-based quantitative real-time PCR for the relative quantification of beak and feather disease virus (BFDV), a pathogen of serious conservation concern for parrots globally. We used this method to test for BFDV in wild crimson rosellas (Platycercus elegans), and compared three different sample types. We detected BFDV in samples from 29 out of 84 individuals (34.5%). However, feather samples provided discordant results concerning virus presence when compared with muscle tissue and blood, and estimates of viral load varied somewhat between different sample types. This study provides evidence for widespread infection of BFDV in wild crimson rosellas, but highlights the importance of sample type when generating and interpreting qualitative and quantitative avian virus data.

The ecology and evolution of beak and feather disease virus in Platycercus elegans

 This thesis explores the complex ecological and evolutionary interactions between beak and feather disease virus and one of its hosts the crimson rosella. The work identifies several factors that predict viral infection in wild birds and determines how host population structure influences viral evolution.

An experimental examination of interindividual variation in feather corticosterone content in the House Sparrow, Passer domesticus in southeast Australia

Non-invasive techniques for measuring glucocorticoids (GCs) have become more prevalent, due to the advantage of eliminating the effects of animal disturbance on GC levels and their potential to provide an integrated, historic estimate of circulating GC levels. In the case of birds, corticosterone (CORT) is deposited in feathers, and may reflect a bird's GC status over the period of feather synthesis. This technique thus permits a retrospective view of the average circulating GC levels during the moult period. While it is generally assumed that differences in feather CORT content (CORTf) between individuals reflects their different stress histories during either natural or induced moult, it is not clear how much of this variation is due to extrinsic versus intrinsic factors. We examined this question by determining CORTf in free-living house sparrows (Passer domesticus) from two populations, one urban and the other rural, that were plucked before and after exposure to different plasma CORT levels while held captive. We experimentally manipulated plasma CORT by implanting birds with either a corticosterone-filled, metyrapone-filled, or empty ('sham') silastic capsule as replacement feathers first emerged. The pattern of post-treatment CORTf was consistent with our expectations, based on plasma CORT levels of an experimentally implanted reference group. However, there was no statistically significant difference in CORTf between these treatment groups unless sex, population origin, and CORTf of original feathers for each individual were included in a model. Thus, birds with higher CORTf in feathers removed for this experiment tended to have higher CORTf in post-treatment replacement feathers, irrespective of treatment. In addition, we found that feather fault bar scores were significantly higher in CORT-treated birds than in the other two treatment groups, but did not vary directly with CORTf level. Our study therefore broadly confirms the use of feathers as a non-invasive tool to estimate plasma CORT during moult in birds, but importantly demonstrates the potential for intrinsic differences in stress characteristics between populations and individuals to obscure the effects extrinsic stressors might have on CORTf .