294 research outputs found

    Protracted development of brain systems underlying working memory in adolescence: a longitudinal study

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    Working memory (WM), the ability to hold information on line to guide planned behavior, continues to improve through adolescence in parallel with brain maturational processes of systems known to support it. Initial studies have only examined individuals once or twice, limiting our understanding of developmental trajectories, leading to sparse and conflicting results. Further, it is unclear how age-related changes in WM performance and neural processes are associated, and what mechanisms might underlie these changes. In this study, we report on developmental improvements of WM performance and changes in brain function and connectivity of systems underlying WM using functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI), in a large longitudinal sample in which participants were followed annually for up to nine years. First, results confirmed that WM performance continues to improve into the early 20's. Alongside these refinements, brain activity in the frontal eye fields (FEF) and parietal cortex continue to change during this time; age-related changes in prefrontal regions were specifically associated with WM performance, suggesting a primary role in WM improvements. Supporting these changes, task-related functional connectivity from dorsolateral prefrontal cortex (DLPFC) to FEF, visual association cortex (VAC), and cingulate regions continued to change during adolescence and were related to WM development. Greater connectivity was associated with less mature behavior, suggesting a decreased reliance on top-down communication to support WM with development. DTI results indicated robust increases in white matter integrity across the brain with the several tracts connecting prefrontal and posterior systems, continuing to mature into early adulthood. Further, white matter measures were correlated with behavior, functional activity, and functional connectivity, suggesting that the development of structural connections may provide a scaffold on which cognitive and functional brain development can specialize. Taken together, these results suggest that while regional prefrontal function supports the transition from childhood to adolescence, the period of transition to adult level WM performance is characterized, by enhancements in prefrontal functional and structural connectivity to posterior regions supporting mnemonic aspects of working memory residing in attention and visual association regions

    The role of fisheries data in the development evaluation and impact assessment in support of European fisheries plans

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    The European Commission has two formal requirements for developing multi-annual management plan policies: evaluation of the past performance of existing plans and impact assessments (IAs) of the potential benefits of new proposals. The new policies require the evaluation of fishery management in terms of three specific criteria: (i) effectiveness, i. e. the best method to achieve the objectives; (ii) efficiency, the cost-effectiveness, and proportionality; and (iii) consistency, i. e. limiting trade-offs across economic, social, and environmental domains. To develop policy, there is a need to collect relevant information, then to conduct appropriate analyses that provide documentation to support the policy objectives. This paper discusses the data requirements for good environmental, economic, and social understanding of fishery dynamics and management, describing how fishery data are currently linked to the analytical and management evaluation process using examples from 2009 and 2010. The type of information currently used is considered, along with the timetable of data availability, and its effect on historical evaluation and IAs, which are now formally required when any changes to legislation are proposed in the European Union, including following stakeholder consultation. The possibilities and future needs for such data are discussed

    Eastern Asian emissions of anthropogenic halocarbons deduced from aircraft concentration data

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    The Montreal Protocol restricts production of ozone-depleting halocarbons worldwide. Enforcement of the protocol has relied mainly on annual government statistics of production and consumption of these compounds (bottom-up approach). We show here that aircraft observations of halocarbon:CO enhancement ratios on regional to continental scales can be used to infer halocarbon emissions, providing independent verification of the bottom-up approach. We apply this top-down approach to aircraft observations of Asian outflow from the TRACE-P mission over the western Pacific (March April 2001) and derive emissions from eastern Asia (China, Japan, and Korea). We derive an eastern Asian carbon tetrachloride (CCl ) source of 21.5 Gg yr , several-fold larger than previous estimates and amounting to 30% of the global budget for this gas. Our emission estimate for CFC-11 from eastern Asia is 50% higher than inventories derived from manufacturing records. Our emission estimates for methyl chloroform (CH ) and CFC-12 are in agreement with existing inventories. For halon 1211 we find only a strong local source originating from the Shanghai area. Our emission estimates for the above gases result in a 40% increase in the ozone depletion potential (ODP) of Asian emissions relative to previous estimates, corresponding to a 10% global increase in ODP

    Clinical application of autologous technetium-99m-labelled eosinophils to detect focal eosinophilic inflammation in the lung.

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    This is the final version of the article. It first appeared from the BMJ Group via http://dx.doi.org/10.1136/thoraxjnl-2015-207156The detection of focal eosinophilic inflammation by non-invasive means may aid the diagnosis and follow-up of a variety of pulmonary pathologies. All current methods of detection involve invasive sampling, which may be contraindicated or too high-risk to be performed safely. The use of injected autologous technetium-99m (Tc-99m)-labelled eosinophils coupled to single-photon emission computed tomography (SPECT) has been demonstrated to localise eosinophilic inflammation in the lungs of a patient with antineutrophil cytoplasmic antibody-positive vasculitis. Here, we report on the utility of this technique to detect active eosinophilic inflammation in a patient with focal lung inflammation where a biopsy was contraindicated.The authors thank all the staff at the Department of Nuclear Medicine at Addenbrooke’s Hospital and the Wellcome Trust Clinical Research Facility, Cambridge; Cambridge Biomedical Research Centre Core Biochemistry Assay Laboratory; and the National Institute for Health Research, through the Comprehensive Clinical Research Network. This work was supported by Asthma-UK [08/11], the Medical Research Council [grant number MR/J00345X/1], the Wellcome Trust [grant number 098351/Z/12/Z], and Cambridge NIHR Biomedical Research Centre. Written informed consent was obtained in accordance with the Declaration of Helsinki. The study was approved by Cambridgeshire Research Ethics Committee (09/H0308/119) and the Administration of Radioactive Substances Advisory Committee of the United Kingdom (83/3130/25000)

    Magnetic resonance imaging of the brain and vocal tract:Applications to the study of speech production and language learning

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    The human vocal system is highly plastic, allowing for the flexible expression of language, mood and intentions. However, this plasticity is not stable throughout the life span, and it is well documented that adult learners encounter greater difficulty than children in acquiring the sounds of foreign languages. Researchers have used magnetic resonance imaging (MRI) to interrogate the neural substrates of vocal imitation and learning, and the correlates of individual differences in phonetic “talent”. In parallel, a growing body of work using MR technology to directly image the vocal tract in real time during speech has offered primarily descriptive accounts of phonetic variation within and across languages. In this paper, we review the contribution of neural MRI to our understanding of vocal learning, and give an overview of vocal tract imaging and its potential to inform the field. We propose methods by which our understanding of speech production and learning could be advanced through the combined measurement of articulation and brain activity using MRI – specifically, we describe a novel paradigm, developed in our laboratory, that uses both MRI techniques to for the first time map directly between neural, articulatory and acoustic data in the investigation of vocalisation. This non-invasive, multimodal imaging method could be used to track central and peripheral correlates of spoken language learning, and speech recovery in clinical settings, as well as provide insights into potential sites for targeted neural interventions

    Vocal Tract Images Reveal Neural Representations of Sensorimotor Transformation During Speech Imitation

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    Imitating speech necessitates the transformation from sensory targets to vocal tract motor output, yet little is known about the representational basis of this process in the human brain. Here, we address this question by using real-time MR imaging (rtMRI) of the vocal tract and functional MRI (fMRI) of the brain in a speech imitation paradigm. Participants trained on imitating a native vowel and a similar nonnative vowel that required lip rounding. Later, participants imitated these vowels and an untrained vowel pair during separate fMRI and rtMRI runs. Univariate fMRI analyses revealed that regions including left inferior frontal gyrus were more active during sensorimotor transformation (ST) and production of nonnative vowels, compared with native vowels; further, ST for nonnative vowels activated somatomotor cortex bilaterally, compared with ST of native vowels. Using test representational similarity analysis (RSA) models constructed from participants' vocal tract images and from stimulus formant distances, we found that RSA searchlight analyses of fMRI data showed either type of model could be represented in somatomotor, temporal, cerebellar, and hippocampal neural activation patterns during ST. We thus provide the first evidence of widespread and robust cortical and subcortical neural representation of vocal tract and/or formant parameters, during prearticulatory ST

    Mediation of the total effect of cystic fibrosis‐related diabetes on mortality: A UK Cystic Fibrosis Registry cohort study

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    Abstract: Aim: To investigate whether the effect of cystic fibrosis‐related diabetes (CFRD) on the composite outcome of mortality or transplant could act through lung function, pulmonary exacerbations and/or nutritional status. Methods: A retrospective cohort of adult cystic fibrosis (CF) patients who had not been diagnosed with CFRD were identified from the UK Cystic Fibrosis Registry (n = 2750). Rate of death or transplant was compared between patients who did and did not develop CFRD (with insulin use) during follow‐up using Poisson regression, separately by sex. Causal mediation methods were used to investigate whether lung function, pulmonary exacerbations and nutritional status lie on the causal pathway between insulin‐treated CFRD and mortality/transplant. Results: At all ages, the mortality/transplant rate was higher in both men and women diagnosed with CFRD. Pulmonary exacerbations were the strongest mediator of the effect of CFRD on mortality/transplant, with an estimated 15% [95% CI: 7%, 28%] of the effect at 2 years post‐CFRD diagnosis attributed to exacerbations, growing to 24% [95% CI: 9%, 46%] at 4 years post‐diagnosis. Neither lung function nor nutritional status were found to be significant mediators of this effect. Estimates were similar but with wider confidence intervals in a cohort that additionally included people with CFRD but not using insulin. Conclusion: There is evidence that pulmonary exacerbations mediate the effect of CFRD on mortality but, as they are estimated to mediate less than one‐quarter of the total effect, the mechanism through which CFRD influences survival may involve other factors

    Deficient crisis-probing practices and taken-for-granted assumptions in health organisations

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    The practice of crisis-probing in proactive organisations involves meticulous and sustained investigation into operational processes and management structures for potential weaknesses and flaws before they become difficult to resolve. In health organisations, crisis probing is a necessary part of preparing to manage emerging health threats. This study examined the degree of pre-emptive probing in health organisations and the type of crisis training provided to determine whether or not they are prepared in this area. This evidence-based study draws on cross-sectional responses provided by executives from chiropractic, physiotherapy, and podiatry practices; dental and medical clinics; pharmacies; aged care facilities; and hospitals. The data show a marked lack of mandatory probing and a generalised failure to reward crisis reporting. Crisis prevention training is poor in all organisations except hospitals and aged care facilities where it occurs at an adequate frequency. However this training focuses primarily on natural disasters, fails to address most other crisis types, is mostly reactive and not designed to probe for and uncover key taken-for-granted assumptions. Crisis-probing in health organisations is inadequate, and improvements in this area may well translate into measurable improvements in preparedness and response outcomes
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