4,970 research outputs found

    Drug therapies for attentional disorders alter the signal-to-noise ratio in the superior colliculus

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    Despite high levels of use, the mechanism of action of effective pharmacotherapies in attention deficit hyperactivity disorder (ADHD) is unknown. It has recently been hypothesized that one site of therapeutic action is the midbrain superior colliculus, a structure traditionally associated with visual processing, but also strongly implicated in distractibility, a core symptom of ADHD. We used male juvenile Wistar rats to examine the effects of therapeutically relevant doses of methylphenidate and d-amphetamine on collicular activity in vitro. Here we report a novel shared mechanism of the two drugs whereby they enhance the signal-to-noise ratio in the superior colliculus. The effects on the signal-to-noise ratio were mediated by serotonin (5-HT) via a pre-synaptic mechanism. This modulatory action would bias the system towards salient events and lead to an overall decrease in distractibility

    Gender differences in the Force Concept Inventory for different educational levels in the United Kingdom

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    The Force Concept Inventory (FCI) is widely used to investigate the effect of education level on conceptual understanding of Newtonian mechanics but has only recently been scrutinized for gender effects and retention. This study examines both the gender gap in first year physics undergraduates compared to the gap for nonphysicists and the FCI retention after three months. All participants were either studying or working at the University of Sheffield in the UK and had completed a similar compulsory level of secondary education. As expected the results show that a greater level of education in physics is associated with a larger average FCI score. However, further analysis shows that there exists a gender gap at all levels of education. The size of the effect of gender is quantified using Cohen’s d and ranges from 0.84 to 1.17 which indicates a large effect due to gender for all levels of education. Despite the FCI having been used as a tool to measure learning gains immediately following instruction in Newtonian mechanics there has been little work to investigate whether this increase in FCI score remains after some time has elapsed. Here the increase in FCI scores is found to remain increased after a three month absence of mechanics-related teaching, and that this retention of FCI scores is independent of gender. Despite this, the gender gap still remains large and statistically significant after the three month delay

    Disentangling quality and safety indicator data: a longitudinal, comparative study of hand hygiene compliance and accreditation outcomes in 96 Australian hospitals.

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    The study aims are twofold. First, to investigate the suitability of hand hygiene as an indicator of accreditation outcomes and, second, to test the hypothesis that hospitals with better accreditation outcomes achieve higher hand hygiene compliance rates

    Trends in healthcare use in children aged less than 15 years; a population-based cohort study in England from 2007 to 2017

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    Objective To describe changing use of primary care in relation to use of urgent care and planned hospital services by children aged less than 15 years in England in the decade following major primary care reforms from 2007 to 2017 Design Population-based retrospective cohort study. Methods We used linked data from the Clinical Practice Research Datalink to study children’s primary care consultations and use of hospital care including emergency department (ED) visits, emergency and elective admissions to hospital and outpatient visits to specialists. Results Between 1 April 2007 and 31 March 2017, there were 7 604 024 general practitioner (GP) consultations, 981 684 ED visits, 287 719 emergency hospital admissions, 2 253 533 outpatient visits and 194 034 elective admissions among 1 484 455 children aged less than 15 years. Age-standardised GP consultation rates fell (−1.0%/year) to 1864 per 1000 child-years in 2017 in all age bands except infants rising by 1%/year to 6722 per 1000/child-years in 2017. ED visit rates increased by 1.6%/year to 369 per 1000 child-years in 2017, with steeper rises of 3.9%/year in infants (780 per 1000 child-years in 2017). Emergency hospital admission rates rose steadily by 3%/year to 86 per 1000 child-years and outpatient visit rates rose to 724 per 1000 child-years in 2017. Conclusions Over the past decade since National Health Service primary care reforms, GP consultation rates have fallen for all children, except for infants. Children’s use of hospital urgent and outpatient care has risen in all ages, especially infants. These changes signify the need for better access and provision of specialist and community-based support for families with young children

    Sexual selection and population divergence III : interspecific and intraspecific variation in mating signals

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    Funding: Orthopterists' Society, Natural Environment Research Council (Grant Number(s): NE/G00949X/1, NE/G014906/1, NE/L011255/1), ARC (Grant Number(s): DP180101708).A major challenge for studying the role of sexual selection in divergence and speciation is understanding the relative influence of different sexually selected signals on those processes in both intra‐ and interspecific contexts. Different signals may be more or less susceptible to co‐option for species identification depending on the balance of sexual and ecological selection acting upon them. To examine this, we tested three predictions to explain geographic variation in long‐ versus short‐range sexual signals across a 3,500 + km transect of two related Australian field cricket species (Teleogryllus spp.): (a) selection for species recognition, (b) environmental adaptation and (c) stochastic divergence. We measured male calling song and male and female cuticular hydrocarbons (CHCs) in offspring derived from wild populations, reared under common garden conditions. Song clearly differentiated the species, and no hybrids were observed suggesting that hybridization is rare or absent. Spatial variation in song was not predicted by geography, genetics or climatic factors in either species. In contrast, CHC divergence was strongly associated with an environmental gradient supporting the idea that the climatic environment selects more directly upon these chemical signals. In light of recently advocated models of diversification via ecological selection on secondary sexual traits, the different environmental associations we found for song and CHCs suggest that the impact of ecological selection on population divergence, and how that influences speciation, might be different for acoustic versus chemical signals.Publisher PDFPeer reviewe

    Evaluation of epidermal growth factor receptors in bladder tumours.

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    Epidermal growth factor (EGF) receptor expression in 31 primary human bladder tumours was quantitated using both structural and functional assays and the EGF receptor gene in the same tumours was analyzed by Southern blot analysis. Immunocytochemical studies using the EGFR1 monoclonal antibody (Mab) showed a significant correlation between EGF receptor levels and the stage and grade of the tumours. Autophosphorylation assays employed to evaluate the receptor's tyrosine kinase activity gave results which in general were consistent with the immunocytochemical data. Using internally controlled immunocytochemical studies with two Mabs and Southern blot analysis of DNA isolated from the tumours, no evidence was obtained for the production of truncated receptors similar to those encoded by the v-erb-B oncogene. Gene amplification was not found in any of the superficial tumours, but one invasive tumour with high EGF receptor expression had an 8-10 fold amplification of the EGF receptor gene. The EGF receptor isolated from this tumour showed a normal pattern of tyrosine phosphorylation at all three major autophosphorylation sites. Our detailed study is consistent with the correlation previously found between EGF receptor expression and stage and grade of bladder tumours, and suggests that at this level of analysis EGF receptors in bladder tumours are not abnormal in structure or size, autophosphorylation activity, or gene structure

    Hepatic transcriptomic profiles from barramundi, Lates calcarifer, as a means of assessing organism health and identifying stressors in rivers in northern Queensland

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    Resource managers need to differentiate between sites with and without contaminants and those where contaminants cause impacts. Potentially, transcriptomes could be used to evaluate sites where contaminant-induced effects may occur, to identify causative stressors of effects and potential adverse outcomes. To test this hypothesis, the hepatic transcriptomes in Barramundi, a perciforme teleost fish, (Lates calcarifer) from two reference sites, two agriculturally impacted sites sampled during the dry season, and an impacted site sampled during the wet season were compared. The hepatic transcriptome was profiled using RNA-Seq. Multivariate analysis showed that transcriptomes were clustered based on site and by inference water quality, but not sampling time. The largest differences in transcriptomic profile were between reference sites and a site sampled during high run-off, showing that impacted sites can be identified via RNA-Seq. Transcripts with altered abundance were linked to xenobiotic metabolism, peroxisome proliferation and stress responses, indicating putative stressors with the potential for adverse outcomes in barramundi

    What’s Worth Talking About? Information Theory Reveals How Children Balance Informativeness and Ease of Production

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    Of all the things we could say, what determines what is worth saying? Greenfield’s principle of informativeness states that, right from the onset of language, humans selectively comment on whatever they find unexpected. We quantify this tendency using information theoretic measures, and test the counterintuitive prediction that children will produce words that are low frequency given the context because these will be most informative. Using corpora of child directed speech, we identified adjectives that varied in how informative (i.e., unexpected) they were given the noun they modified. Three-year-olds (N=31, replication N=13) heard an experimenter use these adjectives to describe pictures. The children’s task was then to describe the pictures to another person. As the information content of the experimenter’s adjective increased, so did children’s tendency to comment on the feature that adjective had encoded. Furthermore, our analyses suggest that children balance this informativeness with a competing drive to ease production
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