35,374 research outputs found

    Charged analogue of Finch-Skea stars

    Get PDF
    We present solutions to the Einstein-Maxwell system of equations in spherically symmetric gravitational fields for static interior spacetimes with a specified form of the electric field intensity. The condition of pressure isotropy yields three category of solutions. The first category is expressible in terms of elementary functions and does not have an uncharged limit. The second category is given in terms of Bessel functions of half-integer order. These charged solutions satisfy a barotropic equation of state and contain Finch-Skea uncharged stars. The third category is obtained in terms of modified Bessel functions of half-integer order and does not have an uncharged limit. The physical features of the charged analogue of the Finch-Skea stars are studied in detail. In particular the condition of causality is satisfied and the speed of sound does not exceed the speed of light. The physical analysis indicates that this analogue is a realistic model for static charged relativistic perfect fluid spheres.Comment: 17 pages, To appear in Int. J. Mod. Phys.

    Technique for Quantitative Mapping of Three-Dimensional Liquid-Gas Phase Boundareis in Microchannel Flows

    Get PDF
    A diagnostic technique capable of characterizing interfaces between transparent, immiscible fluids is developed and demonstrated by investigating the morphology of liquid-gas interfaces in an adiabatic two-phase flow through a microchannel of 500 μm × 500 μm square cross section. Water seeded with 0.5 μm-diameter fluorescent polystyrene particles is pumped through the channel, and the desired adiabatic two-phase flow regime is achieved through controlled air injection. The diagnostic technique relies on obtaining particle position data through epifluorescent imaging of the flow at excitation and emission wavelengths of 532 nm and 620 nm, respectively. The particle position data are then used to resolve interface locations to within ±1 μm in the focal plane. By mapping the interface within individual focal planes at various depths within the channel, it is possible to determine the complete liquid-gas interface geometry across the channel cross section in a dynamic flow environment. Utilizing this approach, the liquid-gas phase boundaries of annular flows within a microchannel have been successfully characterized

    Broadband study of blazar 1ES 1959+650 during flaring state in 2016

    Full text link
    Aim : The nearby TeV blazar 1ES 1959+650 (z=0.047) was reported to be in flaring state during June - July 2016 by Fermi-LAT, FACT, MAGIC and VERITAS collaborations. We studied the spectral energy distributions (SEDs) in different states of the flare during MJD 57530 - 57589 using simultaneous multiwaveband data to understand the possible broadband emission scenario during the flare. Methods : The UV/optical and X-ray data from UVOT and XRT respectively on board Swift and high energy γ\gamma-ray data from Fermi-LAT are used to generate multiwaveband lightcurves as well as to obtain high flux states and quiescent state SEDs. The correlation and lag between different energy bands is quantified using discrete correlation function. The synchrotron self Compton (SSC) model was used to reproduce the observed SEDs during flaring and quiescent states of the source. Results : A decent correlation is seen between X-ray and high energy γ\gamma-ray fluxes. The spectral hardening with increase in the flux is seen in X-ray band. The powerlaw index vs flux plot in γ\gamma-ray band indicates the different emission regions for 0.1 - 3 GeV and 3-300 GeV energy photons. Two zone SSC model satisfactorily fits the observed broadband SEDs. The inner zone is mainly responsible for producing synchrotron peak and high energy γ\gamma-ray part of the SED in all states. The second zone is mainly required to produce less variable optical/UV and low energy γ\gamma-ray emission. Conclusions : Conventional single zone SSC model does not satisfactorily explain broadband emission during observation period considered. There is an indication of two emission zones in the jet which are responsible for producing broadband emission from optical to high energy γ\gamma-rays.Comment: 11 pages, 12 figures, Accepted in A&

    The core competencies for mental, neurological, and substance use disorder care in sub-Saharan Africa.

    Get PDF
    The 2010 Global Burden of Disease Study points to a changing landscape in which non-communicable diseases, such as mental, neurological, and substance use (MNS) disorders, account for an increasing proportion of premature mortality and disability globally. Despite evidence of the need for care, a remarkable deficit of providers for MNS disorder service delivery persists in sub-Saharan Africa. This critical workforce can be developed from a range of non-specialist and specialist health workers who have access to evidence-based interventions, whose roles, and the associated tasks, are articulated and clearly delineated, and who are equipped to master and maintain the competencies associated with providing MNS disorder care. In 2012, the Neuroscience Forum of the Institute of Medicine convened a meeting of key stakeholders in Kampala, Uganda, to discuss a set of candidate core competencies for the delivery of mental health and neurological care, focusing specifically on depression, psychosis, epilepsy, and alcohol use disorders. This article discusses the candidate core competencies for non-specialist health workers and the complexities of implementing core competencies in low- and middle-income country settings. Sub-Saharan Africa, however, has the potential to implement novel training initiatives through university networks and through structured processes that engage ministries of health. Finally, we outline challenges associated with implementing competencies in order to sustain a workforce capable of delivering quality services for people with MNS disorders

    A pilot survey of junior doctors’ attitudes and awareness around medication review: time to change our educational approach?

    Get PDF
    © 2015, BMJ Publishing Group. All rights reserved.Objectives Our aim was to explore junior doctors attitudes and awareness around concepts related to medication review, in order to find ways to change the culture for reviewing, altering and stopping inappropriate or unnecessary medicines. Having already demonstrated the value of team working with senior doctors and pharmacists and the use of a medication review tool, we are now looking to engage first year clinicians and undergraduates in the process. Method An online survey about medication review was distributed among all 42 foundation year one (FY1) doctors at the Chelsea and Westminster Hospital NHS Foundation Trust in November 2014. Descriptive statistics were used for analysis. Results Twenty doctors completed the survey (48%). Of those, 17 believed that it was the pharmacists duty to review medicines; and 15 of 20 stated the general practitioner (GP). Sixteen of 20 stated that they would consult a senior doctor first before stopping medication. Eighteen of 20 considered the GP and consultant to be responsible for alterations, rather than themselves. Sixteen of 20 respondents were not aware of the availability of a medication review tool. Seventeen of 20 felt that more support from senior staff would help them become involved with medication review. Conclusions Junior doctors report feeling uncomfortable altering mediations without consulting a senior first. They appear to be building confidence with prescribing in their first year but not about the medication review process or questioning the drugs already prescribed. Consideration should be given to what we have termed a bottom-up educational approach to provide early experience of and change the culture around medication review, to include the education of undergraduate and foundation doctors and pharmacists
    corecore