Articles by Author: L A Vermeulen

Search results for L A Vermeulen

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  1. Rol van tekorte aan sekere makro-elemente by verdraagsaamheid van mielies (<em>Zea mays</em> L.) teenoor atrasien

    Rol van tekorte aan sekere makro-elemente by verdraagsaamheid van mielies (<em>Zea mays</em> L.) teenoor atrasien

    Item type: Journal Article • Journal: South African Journal of Plant and Soil
    Die verdraagsaamheid van mieliesaailinge (Zea mays L. kv SSM2041) teenoor atrasien is in 'n glashuis ondersoek. Plante is in potte gekweek, in voedingsoplossings met tekorte aan sekere makro-elemente. Atrasien in die voedingsoplossings is periodiek bepaal met behulp van hoëdrukvloeistofchromatografie. Tekorte...
  2. On the sheaf characterization of Gelfand rings

    On the sheaf characterization of Gelfand rings

    Item type: Journal Article • Journal: Quaestiones Mathematicae
    This paper deals with the commutative rings with unit in which a+b = 1 implies that (1+ar)(1+bs) = 0 for suitable r and s. These rings have been considered, alternatively, in terms of conditions on their maximal ideals (DeMarco-Orsatti 1971,...
  3. COMMENTS ON THE WATER QUALITY OF THE MHLATHUZE ESTUARY IN RELATION TO DETERMINING THE ECOLOGICAL INTEGRITY CLASS

    COMMENTS ON THE WATER QUALITY OF THE MHLATHUZE ESTUARY IN RELATION TO DETERMINING THE ECOLOGICAL INTEGRITY CLASS

    Item type: Journal Article • Journal: Southern African Journal of Aquatic Sciences
    Water quality forms an integral component of the determination of the Ecological Reserve of a water resource. This paper presents the available historical and current information on the water quality of the Mhlathuze estuary, The data were assessed in order...
  4. A Group of Black South Africans' Experience of Telling their Untold Stories about the Apartheid Era

    A Group of Black South Africans' Experience of Telling their Untold Stories about the Apartheid Era

    Item type: Journal Article • Journal: Journal of Psychology in Africa
    The aim of this research was to explore a group of black South Africans' experiences of telling their untold stories of survival about the apartheid era. The expectation was that if they did become more aware of these alternative stories,...
  5. The Kleisli Category is a Category Of Fractions

    The Kleisli Category is a Category Of Fractions

    Item type: Journal Article • Journal: Quaestiones Mathematicae
    We consider a generalised notion of category of fractions associated with a class Φ of permitted replacement situations between zig-zags in a category C. The Kleisli category associated with a monad [T, η, μ] in C is shown to be...
  6. Comparison of procedures to evaluate the pathogenicity of Ceratocystisfimbriata sensu lato isolates from Eucalyptus in South Africa

    Comparison of procedures to evaluate the pathogenicity of Ceratocystisfimbriata sensu lato isolates from Eucalyptus in South Africa

    Item type: Journal Article • Journal: Southern Forests: a Journal of Forest Science
    Ceratocystis fimbriata sensu lato (s.l.) is an important pathogen of Eucalyptus. Pathogenicity of isolates has typically been evaluated by inoculating seedlings under greenhouse conditions. It is, however, not clear how accurately this reflects pathogenicity under field conditions. In this study,...
  7. Response of <em>Ocotea bullata</em>, <em>Curtisia dentata</em> and <em>Rapanea melanophloeos</em> to medicinal bark stripping in the southern Cape, South Africa: implications for sustainable use

    Response of <em>Ocotea bullata</em>, <em>Curtisia dentata</em> and <em>Rapanea melanophloeos</em> to medicinal bark stripping in the southern Cape, South Africa: implications for sustainable use

    Item type: Journal Article • Journal: Southern Forests: a Journal of Forest Science
    Tree bark is commonly used for traditional medicine in southern Africa and further afield. Increasing demand and commercialisation have resulted in the overexploitation of many species, posing a major challenge to forest managers to develop mechanisms for sustainable resource use...