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Now showing 1 - 5 of 13
  • Publication
    Studia Geobotanica. An international journal Vol. 8 (1988)
    (EUT Edizioni Università di Trieste, 1988)
      218  696
  • Publication
    I licheni endolitici calcicoli su monumenti
    (EUT Edizioni Università di Trieste, 1988)
    Nimis, P.L.
    ;
    Zappa, L.
    ENDOLITHIC LICHENS ON LIMESTONE MONUMENTS - This paper briefly illustrates the main features of endolithic lichens growing on limestone, with particular regard to some species which have been found growing on monuments. The action of endolithic lichens on stone is also discussed, with some remarks on the possible harmful effects of the application of biocides to remove endolithic lichens from monuments.
      303  1801
  • Publication
    Azione delle crescita dei licheni sulla pietra nell'area archeologica di Fiesole
    (EUT Edizioni Università di Trieste, 1988)
    Pallecchi, P.
    ;
    Pinna, D.
    The archaeological area in Fiesole, where a local sandstone (Pietra Serena) was mainly used, was taken into consideration with the purpose of investigating the mechanical and chemical alteration possibly due to lichen growth. The taxonomic data allowed identification of almost 40 species. Distribution data allowed definition and localization of the most frequent species, therefore permitting a choice of those to be taken into consideration in relation to their effect on the stone. Observation of stone specimens under optical and scanning electron microscopes showed the morphology of mechanical alterations caused by the growth of some lichen species. The map of distribution of calcium determined by analysis carried out under SEM equipped with an energy dispersive X-ray spectrometer (EDS) showed that some species cause modification of the mineralogical stone composition. Moreover, analyses by X-ray diffractometry, in connection with the above results, allow the identification of the production of calcium oxalate due to tlhe growth of some species.
      333  671
  • Publication
    Protective agents as a possible substrate for biogenic cycles
    (EUT Edizioni Università di Trieste, 1988)
    Alessi, P.
    ;
    Visintin, D.
    Protective agents are increasingly used for the preservation of stone monuments. Once applied to the rock, they constitute a veritable new substrate. Very little is known on the biological cycles which could develop on treated surfaces. This paper presents a synthesis on the main properties of protective agents, with particular regard to those of biological relevance; the results were obtained on the basis of multivariate analysis of solubility data. The aim of the paper is to provide biologists with an information basis for studies of biogenic cycles on treated surfaces.
      216  279
  • Publication
    The distribution of lichens on some stoneworks in the surroundings of Rome
    (EUT Edizioni Università di Trieste, 1988)
    Roccardi, A.
    ;
    Bianchetti, P.
    34 floristic releves concerning epilithic lichens have been carried out in 6 archaeological sites in the surroundings of Rome, on different types of substrate. 52 lichen species have been recorded. The matrix of the releves and of the species has been submitted to programs of multivariate analysis (classification and ordination); the results allow to distinguish 5 main community-types and to order the species according to their degrees of acidophytism and nitrophytism.
      321  326