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Matti Narkia

Duration of vitamin D synthesis from weather model data for use in prospective epidemio... - 0 views

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    Duration of vitamin D synthesis from weather model data for use in prospective epidemiological studies.
    Edvardsen K, Engelsen O, Brustad M.
    Int J Biometeorol. 2009 Sep;53(5):451-9. Epub 2009 May 15.
    PMID: 19444487
Matti Narkia

Daily duration of vitamin D synthesis in human skin with relation to latitude, total oz... - 0 views

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    "Daily duration of vitamin D synthesis in human skin with relation to latitude, total ozone, altitude, ground cover, aerosols and cloud thickness."
Matti Narkia

VitD-ez Easy Duration of Vitamin D Synthesis in Human Skin - 0 views

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    Vitamin D production in human skin occurs only when UV radiation exceeds a threshold. From simulations of UV irradiances, the VitD-ez www page ( http://zardoz.nilu.no/~olaeng/fastrt/VitD-ez.html) computes the daily duration of dermal vitamin D production at midday when UV radiation exceeds the required threshold. The VitD-ez www page is a simplified version of the more complex VitD web page ( http://zardoz.nilu.no/~olaeng/fastrt/VitD.html). The simplified VitD-ez www page is convenient for users unfamiliar to radiative transfer modelling, because the model input is limited and more intuitive.
Matti Narkia

Daily duration of vitamin D synthesis in human skin with relation to latitude, total oz... - 1 views

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    Daily duration of vitamin D synthesis in human skin with relation to latitude, total ozone, altitude, ground cover, aerosols and cloud thickness.
    Engelsen O, Brustad M, Aksnes L, Lund E.
    Photochem Photobiol. 2005 Nov-Dec;81(6):1287-90.
    PMID: 16354110

    Vitamin D production in human skin occurs only when incident UV radiation exceeds a certain threshold. From simulations of UV irradiances worldwide and throughout the year, we have studied the dependency of the extent and duration of cutaneous vitamin D production in terms of latitude, time, total ozone, clouds, aerosols, surface reflectivity and altitude. For clear atmospheric conditions, no cutaneous vitamin D production occurs at 51 degrees latitude and higher during some periods of the year. At 70 degrees latitude, vitamin D synthesis can be absent for 5 months. Clouds, aerosols and thick ozone events reduce the duration of vitamin D synthesis considerably, and can suppress vitamin D synthesis completely even at the equator. A web page allowing the computation of the duration of cutaneous vitamin D production worldwide throughout the year, for various atmospheric and surface conditions, is available on the Internet at http://zardoz.nilu.no/~olaeng/fastrt/VitD.html and http://zardoz.nilu.no/~olaeng/fastrt/VitD-ez.html. The computational methodology is outlined here.
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