11 research outputs found

    Polar amplification dominated by local forcing and feedbacks

    No full text
    The surface temperature response to greenhouse gas forcing displays a characteristic pattern of polar-amplified warming1,2,3,4,5, particularly in the Northern Hemisphere. However, the causes of this polar amplification are still debated. Some studies highlight the importance of surface-albedo feedback6,7,8, while others find larger contributions from longwave feedbacks4,9,10, with changes in atmospheric and oceanic heat transport also thought to play a role11,12,13,14,15,16. Here, we determine the causes of polar amplification using climate model simulations in which CO2 forcing is prescribed in distinct geographical regions, with the linear sum of climate responses to regional forcings replicating the response to global forcing. The degree of polar amplification depends strongly on the location of CO2 forcing. In particular, polar amplification is found to be dominated by forcing in the polar regions, specifically through positive local lapse-rate feedback, with ice-albedo and Planck feedbacks playing subsidiary roles. Extra-polar forcing is further shown to be conducive to polar warming, but given that it induces a largely uniform warming pattern through enhanced poleward heat transport, it contributes little to polar amplification. Therefore, understanding polar amplification requires primarily a better insight into local forcing and feedbacks rather than extra-polar processes

    Perceptual abnormalities in clinical high risk youth and the role of trauma, cannabis use and anxiety

    No full text
    Recent research suggests that perceptual abnormalities are a group of diverse experiences, which have been associated with trauma, cannabis use, and anxiety. Of the attenuated psychotic symptoms that are present in youth at clinical high risk (CHR) of psychosis, perceptual abnormalities tend to be one of the most frequently endorsed symptoms. However, very few studies have explored perceptual abnormalities and their relationships with the above environmental and affective factors in a CHR sample. Four hundred and forty-one CHR individuals who met criteria for attenuated psychotic symptom syndrome (APSS) determined by the Structured Interview for Psychosis-risk Syndromes (SIPS) were assessed on the content of their perceptual abnormalities, early traumatic experience, cannabis use and self-reported anxiety. Logistic regression analyses suggested that both simple auditory and simple visual perceptual abnormalities were more likely to be reported by CHR who had early traumatic experiences, who are current cannabis users, and who have higher levels of anxiety. Multiple regression analysis revealed that only trauma and anxiety were independent predictors of both simple auditory and simple visual perceptual abnormalities. It is possible that examining subtypes of perceptual abnormalities in CHR leads to an improved understanding of the prevalence of such symptoms

    Testing and Beyond: Strategies and Tools for Evaluating and Assessing Infants and Toddlers

    No full text

    Chromosomal rearrangement as the basis for human tumourigenesis

    No full text

    Mental Retardation

    No full text
    corecore