127 research outputs found

    Dynamics of the Transition corona

    Get PDF
    Magnetic reconnection between open and closed magnetic field in the corona is believed to play a crucial role in the corona/heliosphere coupling. At large scale, the exchange of open/closed connectivity is expected to occur in pseudo-streamer structures. However, there is neither clear observational evidence of how such coupling occurs in pseudo-streamers, nor evidence for how the magnetic reconnection evolves. Using a newly-developed technique, we enhance the off-limb magnetic fine structures observed with AIA and identify a pseudo-streamer-like feature located close to the northern coronal hole. After extrapolating the magnetic field with the PFSS model, we obtain a pseudo-streamer magnetic topology, null-point related topology bounded by open field. We compare the magnetic configuration with the UV observations and identify the magnetic structures expected to be involved in the event. Using an 3D MHD simulation of interchange reconnection, we showed that the evolution of the UV structures follows the magnetic field dynamics and the UV emitting structures have a pattern very similar to the plasma emission derived from the simulation. Our results highlight that the exchange between open and closed in the pseudo-streamer topology related to an observed event occurs at least partially at the null-point, similarly to the interchange reconnection in a single null-point topology. However, our results also indicate that the interchange reconnection in pseudo-streamers is a gradual physical process which opposes to the impulsive reconnection of the solar-jet model

    Understanding How Ethnic and Cultural Minorities Perceive Peer Support and Recovery: Final Report

    Get PDF
    Overview: Mental health systems transformation has had the promotion of recovery and peer support at its core. In order to better understand how people of different cultural, linguistic, and ethnic backgrounds understand and interpret the concepts of mental health, mental illness, recovery and peer support, the Massachusetts Department of Mental Health (DMH) and MassHealth asked the Center for Health Policy and Research at UMass Medical School to conduct a study exploring these issues. Two specific cultural groups were identified to be the focus of this study – Latinos and individuals who are Deaf and/or Hard of Hearing (D/HH)

    COSIE: The Coronal Spectrographic Imager in the EUV

    Get PDF
    COSIE is a solar-observing instrument (currently proposed for mounting onto the ISS) which obtains wide field images of the corona and full Sun spectral images with high sensitivity and rapid cadence. The primary purpose of the instrument is to constrain the global field topology and to track coronal mass ejections from the disk through the inner heliosphere

    Evidence of Non-Thermal Particles in Coronal Loops Heated Impulsively by Nanoflares

    Full text link
    The physical processes causing energy exchange between the Sun's hot corona and its cool lower atmosphere remain poorly understood. The chromosphere and transition region (TR) form an interface region between the surface and the corona that is highly sensitive to the coronal heating mechanism. High resolution observations with the Interface Region Imaging Spectrograph (IRIS) reveal rapid variability (about 20 to 60 seconds) of intensity and velocity on small spatial scales at the footpoints of hot dynamic coronal loops. The observations are consistent with numerical simulations of heating by beams of non-thermal electrons, which are generated in small impulsive heating events called "coronal nanoflares". The accelerated electrons deposit a sizable fraction of their energy in the chromosphere and TR. Our analysis provides tight constraints on the properties of such electron beams and new diagnostics for their presence in the nonflaring corona.Comment: Published in Science on October 17: http://www.sciencemag.org/content/346/6207/1255724 . 26 pages, 10 figures. Movies are available at: http://www.lmsal.com/~ptesta/iris_science_mov

    Assertive Community Treatment for People With Alcohol Dependence: A Pilot Randomized Controlled Trial

    Get PDF
    Aims: A pilot randomized controlled trial (RCT) to assess the feasibility and potential efficacy of assertive community treatment (ACT) in adults with alcohol dependence. Methods: Single blind, individually randomized, pilot RCT of 12 months of ACT plus treatment as usual (TAU) versus TAU alone in adults (age 18+ years) with alcohol dependence and a history of previous unsuccessful alcohol treatment attending specialist community alcohol treatment services. ACT aimed to actively engage participants for 12 months with assertive, regular, minimum weekly contact. ACT was combined with TAU. TAU comprised access to the full range of services provided by the community teams. Primary outcome is mean drinks per drinking day and percent days abstinent at 12 months follow up. Analysis of covariance was conducted using 80% confidence intervals, appropriate in the context of a pilot trial. Results: A total of 94 participants were randomized, 45 in ACT and 49 in TAU. Follow-up was achieved with 98 and 88%, respectively at 12 months. Those in ACT had better treatment engagement, and were more often seen in their homes or local community than TAU participants. At 12 months the ACT group had more problems related to drinking and lower quality of life than TAU but no differences in drinking measures. The ACT group had a higher percentage of days abstinent but lower quality of life at 6 months. The ACT group had less unplanned healthcare use than TAU. Conclusions: An trial of ACT was feasible to implement in an alcohol dependent treatment population. Trial registration: ISRCTN2277553

    Pragmatic randomised controlled trial to evaluate the effectiveness and cost effectiveness of a multi-component intervention to reduce substance use and risk-taking behaviour in adolescents involved in the criminal justice system: A trial protocol (RISKIT-CJS)

    Get PDF
    Abstract Background Adolescence is a critical developmental stage when young people make lifestyle choices that have the potential to impact on their current and future health and social wellbeing. The relationship between substance use and criminal activity is complex but there is clear evidence that the prevalence of problematic substance use is far higher among adolescent offenders than the general adolescent population. Adolescent offenders are a marginalized and vulnerable population who are significantly more likely to experience health and social inequalities in later life than their non-offending peers. There is a paucity of evidence on effective interventions to address substance use and risk-taking behaviours in adolescent offender populations but it is clear that preventative or abstinence orientated interventions are not effective. RISKIT-CJS is an intervention developed in collaboration with young people taking account of the current best evidence. Feasibility and pilot studies have found the intervention addresses the needs of adolescents, is acceptable and has demonstrated potential in reducing substance use and risk-taking behavior. Methods The study is a mixed method, two-armed, prospective, pragmatic randomized controlled trial with individual randomisation to either treatment as usual alone or the RISKIT-CJS intervention in addition to treatment as usual. Adolescents, aged 13 to 17 years inclusive, engaged with the criminal justice system who are identified as having problematic substance use are eligible to participate. The study will be conducted across three geographical areas; South and South East England, London and North East England between March 2017 and February 2019. Discussion The study represents an ambitious programme of work to address an area of need for a marginalized and vulnerable population. Trial registration ISRCTN77037777 registered 15/09/2016

    Expression of the Multiple Sclerosis-Associated MHC Class II Allele HLA-DRB1*1501 Is Regulated by Vitamin D

    Get PDF
    Multiple sclerosis (MS) is a complex trait in which allelic variation in the MHC class II region exerts the single strongest effect on genetic risk. Epidemiological data in MS provide strong evidence that environmental factors act at a population level to influence the unusual geographical distribution of this disease. Growing evidence implicates sunlight or vitamin D as a key environmental factor in aetiology. We hypothesised that this environmental candidate might interact with inherited factors and sought responsive regulatory elements in the MHC class II region. Sequence analysis localised a single MHC vitamin D response element (VDRE) to the promoter region of HLA-DRB1. Sequencing of this promoter in greater than 1,000 chromosomes from HLA-DRB1 homozygotes showed absolute conservation of this putative VDRE on HLA-DRB1*15 haplotypes. In contrast, there was striking variation among non–MS-associated haplotypes. Electrophoretic mobility shift assays showed specific recruitment of vitamin D receptor to the VDRE in the HLA-DRB1*15 promoter, confirmed by chromatin immunoprecipitation experiments using lymphoblastoid cells homozygous for HLA-DRB1*15. Transient transfection using a luciferase reporter assay showed a functional role for this VDRE. B cells transiently transfected with the HLA-DRB1*15 gene promoter showed increased expression on stimulation with 1,25-dihydroxyvitamin D3 (P = 0.002) that was lost both on deletion of the VDRE or with the homologous “VDRE” sequence found in non–MS-associated HLA-DRB1 haplotypes. Flow cytometric analysis showed a specific increase in the cell surface expression of HLA-DRB1 upon addition of vitamin D only in HLA-DRB1*15 bearing lymphoblastoid cells. This study further implicates vitamin D as a strong environmental candidate in MS by demonstrating direct functional interaction with the major locus determining genetic susceptibility. These findings support a connection between the main epidemiological and genetic features of this disease with major practical implications for studies of disease mechanism and prevention
    • …
    corecore