4,962 research outputs found

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

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    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

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

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    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

    Diffusion-controlled phase growth on dislocations

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    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

    Virtual patients design and its effect on clinical reasoning and student experience : a protocol for a randomised factorial multi-centre study

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    Background Virtual Patients (VPs) are web-based representations of realistic clinical cases. They are proposed as being an optimal method for teaching clinical reasoning skills. International standards exist which define precisely what constitutes a VP. There are multiple design possibilities for VPs, however there is little formal evidence to support individual design features. The purpose of this trial is to explore the effect of two different potentially important design features on clinical reasoning skills and the student experience. These are the branching case pathways (present or absent) and structured clinical reasoning feedback (present or absent). Methods/Design This is a multi-centre randomised 2x2 factorial design study evaluating two independent variables of VP design, branching (present or absent), and structured clinical reasoning feedback (present or absent).The study will be carried out in medical student volunteers in one year group from three university medical schools in the United Kingdom, Warwick, Keele and Birmingham. There are four core musculoskeletal topics. Each case can be designed in four different ways, equating to 16 VPs required for the research. Students will be randomised to four groups, completing the four VP topics in the same order, but with each group exposed to a different VP design sequentially. All students will be exposed to the four designs. Primary outcomes are performance for each case design in a standardized fifteen item clinical reasoning assessment, integrated into each VP, which is identical for each topic. Additionally a 15-item self-reported evaluation is completed for each VP, based on a widely used EViP tool. Student patterns of use of the VPs will be recorded. In one centre, formative clinical and examination performance will be recorded, along with a self reported pre and post-intervention reasoning score, the DTI. Our power calculations indicate a sample size of 112 is required for both primary outcomes

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

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    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

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

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    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

    Control of hyperglycaemia in paediatric intensive care (CHiP): study protocol.

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    BACKGROUND: There is increasing evidence that tight blood glucose (BG) control improves outcomes in critically ill adults. Children show similar hyperglycaemic responses to surgery or critical illness. However it is not known whether tight control will benefit children given maturational differences and different disease spectrum. METHODS/DESIGN: The study is an randomised open trial with two parallel groups to assess whether, for children undergoing intensive care in the UK aged <or= 16 years who are ventilated, have an arterial line in-situ and are receiving vasoactive support following injury, major surgery or in association with critical illness in whom it is anticipated such treatment will be required to continue for at least 12 hours, tight control will increase the numbers of days alive and free of mechanical ventilation at 30 days, and lead to improvement in a range of complications associated with intensive care treatment and be cost effective. Children in the tight control group will receive insulin by intravenous infusion titrated to maintain BG between 4 and 7.0 mmol/l. Children in the control group will be treated according to a standard current approach to BG management. Children will be followed up to determine vital status and healthcare resources usage between discharge and 12 months post-randomisation. Information regarding overall health status, global neurological outcome, attention and behavioural status will be sought from a subgroup with traumatic brain injury (TBI). A difference of 2 days in the number of ventilator-free days within the first 30 days post-randomisation is considered clinically important. Conservatively assuming a standard deviation of a week across both trial arms, a type I error of 1% (2-sided test), and allowing for non-compliance, a total sample size of 1000 patients would have 90% power to detect this difference. To detect effect differences between cardiac and non-cardiac patients, a target sample size of 1500 is required. An economic evaluation will assess whether the costs of achieving tight BG control are justified by subsequent reductions in hospitalisation costs. DISCUSSION: The relevance of tight glycaemic control in this population needs to be assessed formally before being accepted into standard practice

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

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    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

    A comparative framework: how broadly applicable is a 'rigorous' critical junctures framework?

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    The paper tests Hogan and Doyle's (2007, 2008) framework for examining critical junctures. This framework sought to incorporate the concept of ideational change in understanding critical junctures. Until its development, frameworks utilized in identifying critical junctures were subjective, seeking only to identify crisis, and subsequent policy changes, arguing that one invariably led to the other, as both occurred around the same time. Hogan and Doyle (2007, 2008) hypothesized ideational change as an intermediating variable in their framework, determining if, and when, a crisis leads to radical policy change. Here we test this framework on cases similar to, but different from, those employed in developing the exemplar. This will enable us determine whether the framework's relegation of ideational change to a condition of crisis holds, or, if ideational change has more importance than is ascribed to it by this framework. This will also enable us determined if the framework itself is robust, and fit for the purposes it was designed to perform — identifying the nature of policy change
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