The energetics of fish growth and how it constrains food-web trophic structure

This is the author accepted manuscript. The final version is available from Wiley via the DOI in this record.All data and R code (data manipulation, analyses, figures and tables) can be downloaded from a GitHub repository (https://github.com/dbarneche/FishGrowth), which will be made publicly available upon publication.The allocation of metabolic energy to growth fundamentally influences all levels of biological organisation. Here we use a first‐principles theoretical model to characterise the energetics of fish growth at distinct ontogenetic stages and in distinct thermal regimes. Empirically, we show that the mass scaling of growth rates follows that of metabolic rate, and is somewhat steeper at earlier ontogenetic stages. We also demonstrate that the cost of growth, Em, varies substantially among fishes, and that it may increase with temperature, trophic level and level of activity. Theoretically, we show that Em is a primary determinant of the efficiency of energy transfer across trophic levels, and that energy is transferred more efficiently between trophic levels if the prey are young and sedentary. Overall, our study demonstrates the importance of characterising the energetics of individual growth in order to understand constraints on the structure of food webs and ecosystems.Macquarie UniversityCentre for Geometric Biology at Monash Universit

Erratum: A decadal decline in relative abundance and a shift in microphytoplankton composition at a long-term coastal station off southeast Australia

In this study, we examined 11 yr (1998-2009) of water samples collected from Port Hacking coastal monitoring station 8 km offshore from Sydney, Australia, to assess changes in the microphytoplankton in relation to climate-related trends in environmental variables. A total of 152 taxa (85 genera) were identified, with the small diatom Thalassiosira cf. partheneia and the tropical cyanobacterium Trichodesmium erythraeum being the dominant species over the past decade. Taxon richness showed a distinct seasonal pattern, peaking in the austral winter. Ordination analyses revealed significant seasonal and interannual trends in species composition, including a decadal decline in dinoflagellates relative to diatoms toward the present. This decadal shift in taxonomic composition was, in turn, significantly associated with declines in water temperatures over this time period. Total abundance varied by 12 orders of magnitude (8.5 X 10⁻⁸ to 7.4 X 10⁴ cells L⁻¹), with values separable into bloom and nonbloom regimes at an abundance threshold of 7.1 X 10⁻⁵ cells L⁻¹. Significant temporal declines in abundance were observed during both bloom and nonbloom regimes. Blooms occurred most consistently in March, September, and December.13 page(s

Two colliding epidemics - obesity is independently associated with chronic pain interfering with activities of daily living in adults 18 years and over; a cross-sectional, population-based study.

BACKGROUND: Chronic pain interfering with activities of daily living is highly prevalent in the community. More than 600 million people worldwide are obese. The aim of this paper is to assess if such chronic pain is associated independently with obesity across the adult population, having controlled for other key factors. METHODS: The South Australian Health Omnibus is an annual, population-based, cross-sectional study. Data on 2616 participants were analysed for episodes of daily pain for three of the preceding six months. Obesity was derived from self-reported height and weight. Multivariable logistic regression analysed the associations between chronic pain interfering with activities of daily living, body mass index (BMI) and key socio-demographic factors. RESULTS: Chronic pain interfering with activities of daily living peaks in people ≥75 years of age while obesity peaks in the 45-54 age group. Pain and obesity together peak in the 55-74 year age group. In the adjusted multinominal logistic regression model, compared to those with no pain, there was a strong association between obesity and pain that interfered moderately or extremely with day-to-day activities (OR 2.25; 95 % CI 1.57-3.23; p < 0.001) having controlled for respondents' age, gender, rurality, country of birth and highest educational attainment. People over 65 years of age and those with lower educational levels were more likely to experience such chronic pain related to obesity. CONCLUSION: This study demonstrates a strong association between chronic pain and obesity/morbid obesity in the South Australian population. Prospective, longitudinal data are needed to understand the dynamic interaction between these two prevalent conditions

Diffusion-controlled phase growth on dislocations

We treat the problem of diffusion of solute atoms around screw dislocations. In particular, we express and solve the diffusion equation, in radial symmetry, in an elastic field of a screw dislocation subject to the flux conservation boundary condition at the interface of a new phase. We consider an incoherent second-phase precipitate growing under the action of the stress field of a screw dislocation. The second-phase growth rate as a function of the supersaturation and a strain energy parameter is evaluated in spatial dimensions d=2 and d=3. Our calculations show that an increase in the amplitude of dislocation force, e.g. the magnitude of the Burgers vector, enhances the second-phase growth in an alloy. Moreover, a relationship linking the supersaturation to the precipitate size in the presence of the elastic field of dislocation is calculated.Comment: 10 pages, 4 figures, a revised version of the paper presented in MS&T'08, October 5-9, 2008, Pittsburg

Chewing gum benefits sustained attention in the absence of task degradation.

OBJECTIVES: The present study examined the effect of chewing gum on sustained attention and associated changes in subjective alertness. METHODS: In a within-participants design, 20 participants completed an extended version of the sustained attention response task (SART: Robertson et al., 1997), both with and without chewing gum. Self-rated measures of alertness, contentedness, and calmness were taken before and after the SART. RESULTS: Chewing gum was associated with improved attentional task performance. This finding was not contingent upon a general decrease in attentional performance and was apparent at all stages of the task. Subjective measures of alertness, contentedness, and calmness were higher following the chewing of gum. Changes in sustained attention co-varied with subjective alertness. DISCUSSION: The effects of chewing gum on attention and alertness are consistent with past literature and were not contingent on declines in attention. Additionally, we found evidence that gum-induced changes in self-rated alertness and attention are related. We found no support for the proposition that chewing gum can impair attention due to the division of resources

Bifidobacterium longum 1714 as a translational psychobiotic: modulation of stress, electrophysiology and neurocognition in healthy volunteers

The emerging concept of psychobiotics—live microorganisms with a potential mental health benefit—represents a novel approach for the management of stress-related conditions. The majority of studies have focused on animal models. Recent preclinical studies have identified the B. longum 1714 strain as a putative psychobiotic with an impact on stress-related behaviors, physiology and cognitive performance. Whether such preclinical effects could be translated to healthy human volunteers remains unknown. We tested whether psychobiotic consumption could affect the stress response, cognition and brain activity patterns. In a within-participants design, healthy volunteers (N=22) completed cognitive assessments, resting electroencephalography and were exposed to a socially evaluated cold pressor test at baseline, post-placebo and post-psychobiotic. Increases in cortisol output and subjective anxiety in response to the socially evaluated cold pressor test were attenuated. Furthermore, daily reported stress was reduced by psychobiotic consumption. We also observed subtle improvements in hippocampus-dependent visuospatial memory performance, as well as enhanced frontal midline electroencephalographic mobility following psychobiotic consumption. These subtle but clear benefits are in line with the predicted impact from preclinical screening platforms. Our results indicate that consumption of B. longum 1714 is associated with reduced stress and improved memory. Further studies are warranted to evaluate the benefits of this putative psychobiotic in relevant stress-related conditions and to unravel the mechanisms underlying such effects

Can developmental cognitive neuroscience inform intervention for social, emotional and behavioural difficulties (SEBD)?

An initial evaluation of the utility of designing an intervention to address neuroscience-based subtyping of children who have conduct problems was undertaken in this pilot study. Drawing on the literature on callous–unemotional traits, a novel intervention programme, ‘Let's Get Smart’, was implemented in a school for children with social emotional and behavioural difficulties. A mixed-methods design was used to investigate the perspectives of staff participant-observers in the change process, alongside standardised scores on measures of pupil performance and behaviour. Both qualitative and quantitative results showed reductions in externalising behaviour and improvements in measures of hypothesised underlying cognitive and affective processes. While externalising behaviour improved across subtypes, associated changes in underlying processes differed by subtype, supporting the potential value of neuroscience-informed contributions to intervention planning

Is the pharmacy profession innovative enough?: meeting the needs of Australian residents with chronic conditions and their carers using the nominal group technique

Background Community pharmacies are ideally located as a source of support for people with chronic conditions. Yet, we have limited insight into what innovative pharmacy services would support this consumer group to manage their condition/s. The aim of this study was to identify what innovations people with chronic conditions and their carers want from their ideal community pharmacy, and compare with what pharmacists and pharmacy support staff think consumers want. Methods We elicited ideas using the nominal group technique. Participants included people with chronic conditions, unpaid carers, pharmacists and pharmacy support staff, in four regions of Australia. Themes were identified via thematic analysis using the constant comparison method. Results Fifteen consumer/carer, four pharmacist and two pharmacy support staff groups were conducted. Two overarching themes were identified: extended scope of practice for the pharmacist and new or improved pharmacy services. The most innovative role for Australian pharmacists was medication continuance, within a limited time-frame. Consumers and carers wanted improved access to pharmacists, but this did not necessarily align with a faster or automated dispensing service. Other ideas included streamlined access to prescriptions via medication reminders, electronic prescriptions and a chronic illness card. Conclusions This study provides further support for extending the pharmacist’s role in medication continuance, particularly as it represents the consumer’s voice. How this is done, or the methods used, needs to optimise patient safety. A range of innovative strategies were proposed and Australian community pharmacies should advocate for and implement innovative approaches to improve access and ensure continuity of care