The use of hydro-ecological models in the Netherlands

On 25 May 1993 the Technical Meeting 51 of the TNO Committee on Hydrological Research (CHO-TNO) was held in Ede, the Netherlands, on the theme: "The use of hydro-ecological models in the Netherlands". This meeting, organized in cooperation with the Dutch Association for Landscape Ecology (WLO), was a follow-up of the WLO-meeting "Hydro-ecological prediction methods for Policy and Management", held in Ede, the Netherlands, on 15 November 1991. The main target of the meeting was to offer the potential users a better insight into the available hydro-ecological model types, and to show makers of models the possibilities of other methods. This publication contains the papers presented at this meeting. In the Netherlands one of the largest environmental stresses to vegetations in nature reserves is the structural lowering of the ground water levels and the physical and chemical alterations, triggered by this lowering, at the site of these vegetations. Manmade interventions in the water management cause this environmental stress leading to adversal ecological effects. In the Netherlands this environmental stress is called "verdroging". In the English language an equivalent term does not exist, so in this publication different (Dutch) authors use different (litteral) terms. You will find the terms "drought damage" in nature conservation areas (Claessen, Witte et al.), "desiccation" (Latour, Barendregt et al.) and "verdroging" (Garritsen). Another term used in this publication is "dehydration of wetlands and forests". In fact all these terms mean the same, but the taste of the authors is different

Comparison of acetate inhibition on growth of host and recombinant E. coli K12 strains

10.1007/BF01027012Biotechnology Letters14121115-1118BILE

The Plasmodium falciparum Erythrocyte Invasion Ligand Pfrh4 as a Target of Functional and Protective Human Antibodies against Malaria

BACKGROUND: Acquired antibodies are important in human immunity to malaria, but key targets remain largely unknown. Plasmodium falciparum reticulocyte-binding-homologue-4 (PfRh4) is important for invasion of human erythrocytes and may therefore be a target of protective immunity. METHODS: IgG and IgG subclass-specific responses against different regions of PfRh4 were determined in a longitudinal cohort of 206 children in Papua New Guinea (PNG). Human PfRh4 antibodies were tested for functional invasion-inhibitory activity, and expression of PfRh4 by P. falciparum isolates and sequence polymorphisms were determined. RESULTS: Antibodies to PfRh4 were acquired by children exposed to P. falciparum malaria, were predominantly comprised of IgG1 and IgG3 subclasses, and were associated with increasing age and active parasitemia. High levels of antibodies, particularly IgG3, were strongly predictive of protection against clinical malaria and high-density parasitemia. Human affinity-purified antibodies to the binding region of PfRh4 effectively inhibited erythrocyte invasion by P. falciparum merozoites and antibody levels in protected children were at functionally-active concentrations. Although expression of PfRh4 can vary, PfRh4 protein was expressed by most isolates derived from the cohort and showed limited sequence polymorphism. CONCLUSIONS: Evidence suggests that PfRh4 is a target of antibodies that contribute to protective immunity to malaria by inhibiting erythrocyte invasion and preventing high density parasitemia. These findings advance our understanding of the targets and mechanisms of human immunity and evaluating the potential of PfRh4 as a component of candidate malaria vaccines

Integrated screening validates primary axes of specialisation in plants

Standardised procedures have been used to measure 67 traits in 43 common plants of the British flora. This paper provides an interpretation of the most consistent patterns in the resulting matrix by means of correlation, ordination and classification analyses. Only a weak coupling was observed between attributes of the regenerative and established phases of the life history. However, within each phase, attributes were strongly aggregated into sets and a high proportion of the variation between species coincided with a single axis. Attributes of the established phase displayed remarkably consistent trends, with a strong 'Axis I' being identified by three different multivariate methods. There was a marked correlation between foliar concentrations of N, P, K, Ca and Mg, high concentrations of which coincided with the capacity for rapid growth in productive conditions and an inability to sustain yield under limiting supplies of nutrients. A diverse array of other traits, less immediately involving mineral nutrients, were also entrained in Axis I; these included life history, root and shoot foraging, the morphology, longevity, tensile strength and palatability of leaves, and the decomposition rate of leaf litter. This pattern occurred in both monocotyledons and dicotyledons and appeared to reflect a tradeoff between attributes conferring an ability for high rates of resource acquisition in productive habitats and those responsible for retention of resource capital in unproductive conditions. The second axis of variation evident in the established phase was related to phylogeny and distinguished between monocotyledons and dicotyledons on the basis of a diverse set of traits including genome size, cell size, root and shoot foraging characteristics and vascular tissues. A third axis was detected in which ephemerals and perennials were separated by differences in attributes such as breeding system, leaf decomposition rate and a set of traits reflecting the small stature of many short-lived plants. In the regenerative phase, the leading axis was clearly related to the widely recognized tradeoff between seed size and seed number and was consistent with current understanding of seed banks, and with modern theories explaining species coexistence in terms of complementary responses to temporal and spatial variation in vegetation gap dynamics. The data provide strong evidence of functional integration between evolutionary specializations in root and shoot and support Donald's unified theory of competitive ability. The data are not consistent with theories of functional types based upon evolutionary tradeoffs in allocation between root and shoot. We suggest that the evidence assembled here and elsewhere in the current literature points to the existence of primary functional types, including those recognized by Ramenskii and Grime. These functional types can be reconciled with the individuality of plant ecologies in the field and provide an effective basis for interpretation and prediction at various scales from the plant community to regional floras. There are particular opportunities for prediction of successional trajectories, the role of herbivores in vegetation succession and the response of vegetation to eutrophication and extreme climatic events. It is also suggested that aspects of this investigation may provide a Darwinian underpinning for Odum's theory of ecosystem maturation