116 research outputs found

    Cassowary casques act as thermal windows

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    Many ideas have been put forward for the adaptive value of the cassowary casque; and yet, its purpose remains speculative. Homeothermic animals elevate body temperature through metabolic heat production. Heat gain must be offset by heat loss to maintain internal temperatures within a range for optimal performance. Living in a tropical climate, cassowaries, being large bodied, dark feathered birds, are under thermal pressure to offload heat. We tested the original hypothesis that the casque acts as a thermal window. With infrared thermographic analyses of living cassowaries over an expansive range of ambient temperatures, we provide evidence that the casque acts as a thermal radiator, offloading heat at high temperatures and restricting heat loss at low temperatures. Interestingly, at intermediate temperatures, the casque appears thermally heterogeneous, with the posterior of the casque heating up before the front half. These findings might have implications for the function of similar structures in avian and non-avian dinosaurs

    Effect of classroom-based physical activity interventions on academic and physical activity outcomes: a systematic review and meta-analysis

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    BACKGROUND: Physical activity is associated with many physical and mental health benefits, however many children do not meet the national physical activity guidelines. While schools provide an ideal setting to promote children\u27s physical activity, adding physical activity to the school day can be difficult given time constraints often imposed by competing key learning areas. Classroom-based physical activity may provide an opportunity to increase school-based physical activity while concurrently improving academic-related outcomes. The primary aim of this systematic review and meta-analysis was to evaluate the impact of classroom-based physical activity interventions on academic-related outcomes. A secondary aim was to evaluate the impact of these lessons on physical activity levels over the study duration. METHODS: A systematic search of electronic databases (PubMed, ERIC, SPORTDiscus, PsycINFO) was performed in January 2016 and updated in January 2017. Studies that investigated the association between classroom-based physical activity interventions and academic-related outcomes in primary (elementary) school-aged children were included. Meta-analyses were conducted in Review Manager, with effect sizes calculated separately for each outcome assessed. RESULTS: Thirty-nine articles met the inclusion criteria for the review, and 16 provided sufficient data and appropriate design for inclusion in the meta-analyses. Studies investigated a range of academic-related outcomes including classroom behaviour (e.g. on-task behaviour), cognitive functions (e.g. executive function), and academic achievement (e.g. standardised test scores). Results of the meta-analyses showed classroom-based physical activity had a positive effect on improving on-task and reducing off-task classroom behaviour (standardised mean difference = 0.60 (95% CI: 0.20,1.00)), and led to improvements in academic achievement when a progress monitoring tool was used (standardised mean difference = 1.03 (95% CI: 0.22,1.84)). However, no effect was found for cognitive functions (standardised mean difference = 0.33 (95% CI: -0.11,0.77)) or physical activity (standardised mean difference = 0.40 (95% CI: -1.15,0.95)). CONCLUSIONS: Results suggest classroom-based physical activity may have a positive impact on academic-related outcomes. However, it is not possible to draw definitive conclusions due to the level of heterogeneity in intervention components and academic-related outcomes assessed. Future studies should consider the intervention period when selecting academic-related outcome measures, and use an objective measure of physical activity to determine intervention fidelity and effects on overall physical activity levels

    Oleic Acid Counters Impaired Blastocyst Development Induced by Palmitic Acid During Mouse Preimplantation Development: Understanding Obesity-Related Declines in Fertility

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    Obesity is associated with altered fatty acid profiles, reduced fertility, and assisted reproductive technology (ART) success. The effects of palmitic acid (PA), oleic acid (OA), and their combination on mouse preimplantation development, endoplasmic reticulum (ER) stress pathway gene expression, lipid droplet formation, and mitochondrial reactive oxygen species (ROS) were characterized. Two-cell stage mouse embryos collected from superovulated and mated CD1 females were placed into culture with KSOMaa medium, or PA alone or in combination with OA for 46 h. PA significantly reduced blastocyst development in a concentration-dependent manner, which was prevented by co-treatment with OA. PA and OA levels in mouse reproductive tracts were assessed by liquid chromatography coupled to mass spectrometry (LC-MS). LC-MS indicated higher concentrations of PA in the mouse oviduct than the uterus. Transcript analysis revealed that PA alone groups had increased ER stress pathway (ATF3, CHOP, and XBP1 splicing) mRNAs, which was alleviated by OA co-treatment. OA co-treatment significantly increased lipid droplet accumulation and significantly decreased mitochondrial ROS from PA treatment alone. PA treatment for only 24 h significantly reduced its impact on blastocyst development from the 2-cell stage. Thus, PA affects ER stress pathway gene expression, lipid droplet accumulation, and mitochondrial ROS in treated preimplantation embryos. These mechanisms may serve to offset free fatty acid exposure effects on preimplantation development, but their protective ability may be overwhelmed by elevated PA

    Design and methods of the Longitudinal Eating Disorders Assessment Project research consortium for veterans

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    Introduction Military service members must maintain a certain body mass index and body fat percentage. Due to weight-loss pressures, some service members may resort to unhealthy behaviors that place them at risk for the development of an eating disorder (ED). Objectives To understand the scope and impact of EDs in military service members and veterans, we formed the Longitudinal Eating Disorders Assessment Project (LEAP) Consortium. LEAP aims to develop novel screening, assessment, classification, and treatment tools for veterans and military members with a focus on EDs and internalizing psychopathology. Methods We recruited two independent nationally representative samples of post-9/11 veterans who were separated from service within the past year. Study 1 was a four-wave longitudinal survey and Study 2 was a mixed-methods study that included surveys, structured-clinical interviews, and qualitative interviews. Results Recruitment samples were representative of the full population of recently separated veterans. Sample weights were created to adjust for sources of non-response bias to the baseline survey. Attrition was low relative to past studies of this population, with only (younger) age predicting attrition at 1-week follow-up. Conclusions We expect that the LEAP Consortium data will contribute to improved information about EDs in veterans, a serious and understudied problem

    Associations Among Stress, Anxiety, Depression, and Emotional Intelligence Among Veterinary Medicine Students

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    Background: Veterinary students are faced with immense pressures and rigors during school. These pressures have contributed to elevated levels of stress, anxiety, and depression (SAD) among veterinary students relative to the general population. One proposed concept to help students combat SAD is that of emotional intelligence (EI). We explored the relationship between EI and SAD among veterinary students at a college in the Southeast United States. Methods: A crosssectional study design was implemented among a convenience sample of 182 veterinary medical students. The survey instrument contained 56 items that elicited information about students’ demographics, perceived stress, anxiety, and depression, and emotional intelligence levels. Data analysis included univariate statistics, Pearson’s correlations, and multiple regression and independent samples t‐tests. Results: The study revealed a statistically significant, negative correlation between EI levels and stress, anxiety, and depression. Additionally, a statistically significant, positive correlation was found between stress and anxiety as well as both stress and anxiety and depression. Multiple linear regression showed that EI was a statistically significant predictor of stress (b = −0.239, p \u3c 0.001), anxiety (b = −0.044, p \u3c 0.001), and depression (b = −0.063, p \u3c 0.001), after controlling for sociodemographic variables. Students’ t‐test results revealed a statistically significant mean difference in EI scores among students screening positive versus negative for depression, with students screening negative having a mean EI score of 10.81 points higher than students who screened positive for depression. Conclusion: There is a scientifically supported need for interventions in veterinary school to integrate EI into the veterinary medical curriculum and consider the EI levels of veterinary student candidates

    An economic evaluation of targeted case-finding strategies for identifying postnatal depression: A model-based analysis comparing common case-finding instruments

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    BackgroundHalf of women with postnatal depression (PND) are not identified in routine care. We aimed to estimate the cost-effectiveness of PND case-finding in women with risk factors for PND.MethodsA decision tree was developed to represent the one-year costs and health outcomes associated with case-finding and treatment for PND. The sensitivity and specificity of case-finding instruments, and prevalence and severity of PND, for women with ≥1 PND risk factor were estimated from a cohort of postnatal women. Risk factors were history of anxiety/depression, age ResultsMore than half of the cohort had one or more PND risk factor (57.8 %; 95 % CI 52.7 %-62.7 %). The most cost-effective case-finding strategy was the Edinburgh Postnatal Depression Scale with a cut-off of ≥10 (EPDS-10). Among high-risk women, there is a high probability that EPDS-10 case-finding for PND is cost-effective compared to no case-finding (78.5 % at a threshold of £20,000/QALY), with an ICER of £8146/QALY gained. Universal case-finding is even more cost-effective at £2945/QALY gained (versus no case-finding). There is a greater health improvement with universal rather than targeted case-finding.LimitationsThe model includes costs and health benefits for mothers in the first year postpartum, the broader (e.g. families, societal) and long-term impacts are also important.ConclusionsUniversal PND case-finding is more cost-effective than targeted case-finding which itself is more cost-effective than not case-finding

    Reversed T cell receptor docking on a major histocompatibility class I complex limits involvement in the immune response

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    The anti-viral T cell response is drawn from the naive T cell repertoire. During influenza infection, the CD8+ T cell response to an H-2Db-restricted nucleoprotein epitope (NP366) is characterized by preferential expansion of T cells bearing TRBV13+ T cell receptors (TCRs) and avoidance of TRBV17+ T cells, despite the latter dominating the naive precursor repertoire. We found two TRBV17+ TCRs that bound H-2Db-NP366 with a 180° reversed polarity compared to the canonical TCR-pMHC-I docking. The TRBV17 β-chain dominated the interaction and, whereas the complementarity determining region-3 (CDR3) loops exclusively mediated contacts with the MHC-I, peptide specificity was attributable to germline-encoded recognition. Nevertheless, the TRBV17+ TCR exhibited moderate affinity toward H-2Db-NP366 and was capable of signal transduction. Thus, the naive CD8+ T cell pool can comprise TCRs adopting reversed pMHC-I docking modes that limit their involvement in the immune response

    A cross-sectional seroepidemiological survey of typhoid fever in Fiji

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    Fiji, an upper-middle income state in the Pacific Ocean, has experienced an increase in confirmed case notifications of enteric fever caused by Salmonella enterica serovar Typhi (S. Typhi). To characterize the epidemiology of typhoid exposure, we conducted a cross-sectional sero-epidemiological survey measuring IgG against the Vi antigen of S. Typhi to estimate the effect of age, ethnicity, and other variables on seroprevalence. Epidemiologically relevant cut-off titres were established using a mixed model analysis of data from recovering culture-confirmed typhoid cases. We enrolled and assayed plasma of 1787 participants for anti-Vi IgG; 1,531 of these were resident in mainland areas that had not been previously vaccinated against S. Typhi (seropositivity 32.3% (95%CI 28.2 to 36.3%)), 256 were resident on Taveuni island, which had been previously vaccinated (seropositivity 71.5% (95%CI 62.1 to 80.9%)). The seroprevalence on the Fijian mainland is one to two orders of magnitude higher than expected from confirmed case surveillance incidence, suggesting substantial subclinical or otherwise unreported typhoid. We found no significant differences in seropositivity prevalences by ethnicity, which is in contrast to disease surveillance data in which the indigenous iTaukei Fijian population are disproportionately affected. Using multivariable logistic regression, seropositivity was associated with increased age (odds ratio 1.3 (95% CI 1.2 to 1.4) per 10 years), the presence of a pit latrine (OR 1.6, 95%CI 1.1 to 2.3) as opposed to a septic tank or piped sewer, and residence in settlements rather than residential housing or villages (OR 1.6, 95% CI 1.0 to 2.7). Increasing seropositivity with age is suggestive of low-level endemic transmission in Fiji. Improved sanitation where pit latrines are used and addressing potential transmission routes in settlements may reduce exposure to S. Typhi. Widespread unreported infection suggests there may be a role for typhoid vaccination in Fiji, in addition to public health management of cases and outbreaks.Fieldwork was funded by the World Health Organization Western Pacific Region (www. wpro.who.int) and by the Chadwick Trust(ucl.ac. uk/srs/our-services/academic-services/chadwicktrust). CHW is supported by the UK Medical Research Council (grant MR/J003999/1, mrc.ac. uk). SB and RdA are funded by the Wellcome Trust of Great Britain (wellcome.ac.uk). CLL was supported by a research grant from the Global Change Institute (607562) at The University of Queensland (uq.edu.au
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