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Browsing by Author "Vieira, Bruno"

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  • Additions to the lichen flora found on Cryptomeria japonica D. Don, in the Azores.
    Publication . Rodrigues, António F.; Aptroot, André; Freitas, Maria do Carmo; Sousa, Eva; Rodrigues, Carla; Amaral, Ana Sofia; Vieira, Bruno; Soares, Paula
    Twenty-nine lichens species were reported in samples from Azorean Cryptomeria japonica forests. One species, Ramalina peruviana Ach., is newly recorded for the Macaronesian Region. On Cryptomeria japonica, seven new lichen records were found for the Azores: Parmotrema bangii (Vain.) Hale, Pyrrospora quernea (Dickson) Körber, Pyxine subcinerea Stirt., Ramalina implectens Nyl., Ramalina peruviana Ach., Usnea dasaea Stirton and Usnea esperantiana P. Clerc.The species Ramalina peruviana Ach., is rare within the Macaronesian Region.
    2004Journal article Open access Show more
  • The Aethalometer calibration and determination of iron concentration in dust aerosols
    Publication . Fialho, Paulo; Freitas, Maria do Carmo; Barata, Filipe; Vieira, Bruno; Hansen, Anthony; Honrath, Richard
    This paper shows the use of the instrumental neutron activation analysis (INAA) technique to calibrate Aethalometer instruments’ response to iron oxides present in Saharan dust aerosol. The five samples selected for this calibration were collected with a seven-wavelength Aethalometer (model AE31) at the summit of Pico mountain (2225 m ASL) in the Azores Islands. These samples correspond to measurements taken between the 31 October and 5 November, 2001. Analysis of these samples by the INAA technique gave a total mass of 14.84 ± 0.70 μg (Fe). Correlation of the analytical results with the optical measurements allowed the determination of the elemental iron calibration constant, KFe (0.234 ±0.022 μm4 m² gˉ¹), which can be used in the determination of iron concentrations from multi-wavelength Aethalometer measurements. As an example of this, we used Aethalometer measurements during the 2001 event to calculate hourly average dust iron, 〈CFe〉, concentrations, which range from 0.00 and 1.77 μg (Fe) mˉ³.
    2006-11Journal article Restricted access Show more