864 research outputs found

    Extreme star formation events in quasar hosts over 0.5<z<4{\bf0.5<\textit{z}<4}

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    We explore the relationship between active galactic nuclei and star formation in a sample of 513 optically luminous type 1 quasars up to redshifts of \sim4 hosting extremely high star formation rates (SFRs). The quasars are selected to be individually detected by the \textit{Herschel} SPIRE instrument at >> 3σ\sigma at 250 μ\mum, leading to typical SFRs of order of 1000 M_{\odot}yr1^{-1}. We find the average SFRs to increase by almost a factor 10 from z0.5z\sim0.5 to z3z\sim3, mirroring the rise in the comoving SFR density over the same epoch. However, we find that the SFRs remain approximately constant with increasing accretion luminosity for accretion luminosities above 1012^{12} L_{\odot}. We also find that the SFRs do not correlate with black hole mass. Both of these results are most plausibly explained by the existence of a self-regulation process by the starburst at high SFRs, which controls SFRs on time-scales comparable to or shorter than the AGN or starburst duty cycles. We additionally find that SFRs do not depend on Eddington ratio at any redshift, consistent with no relation between SFR and black hole growth rate per unit black hole mass. Finally, we find that high-ionisation broad absorption line (HiBAL) quasars have indistinguishable far-infrared properties to those of classical quasars, consistent with HiBAL quasars being normal quasars observed along a particular line of sight, with the outflows in HiBAL quasars not having any measurable effect on the star formation in their hosts.Comment: 12 pages, 6 figure

    The 2014 Ontario Child Health Study Emotional Behavioural Scales (OCHS-EBS) Part II: Psychometric Adequacy for Categorical Measurement of Selected DSM-5 Disorders

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    Objectives: To compare the reliability and convergent validity of parent assessments from the Mini International Neuropsychiatric Interview for Children and Adolescents (MINI-KID—a structured diagnostic interview) and the Ontario Child Health Study Emotional Behavioural Scales (OCHS-EBS) symptom checklist for classifying conduct disorder (CD), conduct disorder or oppositional defiant disorder (CD-ODD), attention-deficit hyperactivity disorder (ADHD), major depressive disorder (MDD), generalized anxiety disorder (GAD), and separation anxiety disorder (SAD) based on DSM-5 criteria. Methods: Data came from 283 parent-youth dyads aged 9 to 18 years. Parents and youth completed the assessments separately on 2 different occasions 7 to 14 days apart. After converting the OCHS-EBS scale scores to binary disorder classifications, we compare test-retest reliability estimates and use structural equation modelling (SEM) to compare estimates of convergent validity for the same disorders assessed by each instrument. Results: Average test-retest reliabilities based on κ were 0.71 (MINI-KID) and 0.67 (OCHS-EBS). The average β coefficients for 3 latent measures comprising the following indicators—parent perceptions of youth mental health need and impairment, diagnosis of specific disorders based on health professional communications and youth taking prescribed medication, and youth classifications of disorder based on the MINI-KID—were 0.67 (MINI-KID) and 0.69 (OCHS-EBS). Conclusion: The OCHS-EBS and MINI-KID achieve comparable levels of reliability and convergent validity for classifying child psychiatric disorder. The flexibility, low cost, and minimal respondent burden of checklists for classifying disorder make them well suited for studying disorder in the general population and screening in clinical settings

    Intracranial EEG structure-function coupling predicts surgical outcomes in focal epilepsy

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    Alterations to structural and functional brain networks have been reported across many neurological conditions. However, the relationship between structure and function -- their coupling -- is relatively unexplored, particularly in the context of an intervention. Epilepsy surgery alters the brain structure and networks to control the functional abnormality of seizures. Given that surgery is a structural modification aiming to alter the function, we hypothesized that stronger structure-function coupling preoperatively is associated with a greater chance of post-operative seizure control. We constructed structural and functional brain networks in 39 subjects with medication-resistant focal epilepsy using data from intracranial EEG (pre-surgery), structural MRI (pre-and post-surgery), and diffusion MRI (pre-surgery). We investigated pre-operative structure-function coupling at two spatial scales a) at the global iEEG network level and b) at the resolution of individual iEEG electrode contacts using virtual surgeries. At global network level, seizure-free individuals had stronger structure-function coupling pre-operatively than those that were not seizure-free regardless of the choice of interictal segment or frequency band. At the resolution of individual iEEG contacts, the virtual surgery approach provided complementary information to localize epileptogenic tissues. In predicting seizure outcomes, structure-function coupling measures were more important than clinical attributes, and together they predicted seizure outcomes with an accuracy of 85% and sensitivity of 87%. The underlying assumption that the structural changes induced by surgery translate to the functional level to control seizures is valid when the structure-functional coupling is strong. Mapping the regions that contribute to structure-functional coupling using virtual surgeries may help aid surgical planning

    The 2014 Ontario Child Health Study Emotional Behavioural Scales (OCHS-EBS) Part I: A Checklist for Dimensional Measurement of Selected DSM-5 Disorders

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    Objectives: To describe the development and psychometric properties of the 2014 Ontario Child Health Study Emotional Behavioural Scales (OCHS-EBS) for dimensional measurement of 7 disorders based on criteria from the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). Methods: Scale items were selected by agreement among 19 child psychologists and psychiatrists rating the correspondence between item descriptions and DSM-5 symptoms. Psychometric evaluation of the item properties and parent/caregiver and youth scales came from a general population study of 10,802 children and youth aged 4 to 17 years in 6537 families. Test-retest reliability data were collected from a subsample of 280 children and their caregivers who independently completed the OCHS-EBS checklist on 2 occasions 7 to 14 days apart. Structural equation modelling was used to assess internal and external convergent and discriminant validity—the latter tested against the Mini International Neuropsychiatric Interview for Children and Adolescents (MINI-KID). Results: Confirmatory factor analyses exhibited adequate item fit to all scales. Except for conduct disorder and youth-assessed separation anxiety disorder, internal (Cronbach’s α) and test-retest reliability (Pearson’s r) for scale scores were 0.70 or above. Except for youth-assessed conduct disorder, the OCHS-EBS met criteria for internal and convergent and discriminant validity. Compared with the MINI-KID, the OCHS-EBS met criteria for external convergent and discriminant validity. Conclusions: The OCHS-EBS provide reliable and valid dimensional measurement of 7 DSM-5 disorders assessed by caregivers and youth in the general population. Part II describes use of the OCHS-EBS as a categorical (present/absent) measure of disorder

    Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

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    Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy

    Identification of a novel locus on chromosome 2q13, which predisposes to clinical vertebral fractures independently of bone density.

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    OBJECTIVES: To identify genetic determinants of susceptibility to clinical vertebral fractures, which is an important complication of osteoporosis. METHODS: Here we conduct a genome-wide association study in 1553 postmenopausal women with clinical vertebral fractures and 4340 controls, with a two-stage replication involving 1028 cases and 3762 controls. Potentially causal variants were identified using expression quantitative trait loci (eQTL) data from transiliac bone biopsies and bioinformatic studies. RESULTS: A locus tagged by rs10190845 was identified on chromosome 2q13, which was significantly associated with clinical vertebral fracture (P=1.04×10-9) with a large effect size (OR 1.74, 95% CI 1.06 to 2.6). Bioinformatic analysis of this locus identified several potentially functional SNPs that are associated with expression of the positional candidate genes TTL (tubulin tyrosine ligase) and SLC20A1 (solute carrier family 20 member 1). Three other suggestive loci were identified on chromosomes 1p31, 11q12 and 15q11. All these loci were novel and had not previously been associated with bone mineral density or clinical fractures. CONCLUSION: We have identified a novel genetic variant that is associated with clinical vertebral fractures by mechanisms that are independent of BMD. Further studies are now in progress to validate this association and evaluate the underlying mechanism

    Patients' preferences for subcutaneous trastuzumab versus conventional intravenous infusion for the adjuvant treatment of HER2-positive early breast cancer: final analysis of 488 patients in the international, randomized, two-cohort PrefHer study

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    PrefHer revealed compelling and consistent patient preference for subcutaneous (s.c.) trastuzumab, regardless of delivery by single-use injection device or hand-held syringe. s.c. trastuzumab was well-tolerated and safety data, including immunogenicity, were consistent with previous reports. No new safety signals were identified compared with the known intravenous trastuzumab profile in early breast cance
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