John Hearne

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Recent theoretical studies have shown that spatial redistribution of surface water may explain the occurrence of patterns of alternating vegetated and degraded patches in semiarid grasslands. These results implied, however, that spatial redistribution processes cannot explain the collapse of production on coarser scales observed in these systems. We present(More)
BACKGROUND Transfer factor of the lung for carbon monoxide (TLCO) was measured by a new method based on analysis of the ratio of the concentrations of carbon monoxide to an inert gas (methane) relative to lung volume during a constant exhalation. Since this new technique is based solely upon exhalation, anomalies associated with inspiration and breath(More)
We studied fine-scale spatial plant distribution in relation to the spatial distribution of erodible soil particles, organic matter, nutrients and soil water on a sandy to sandy loam soil in the Sahel. We hypothesized that the distribution of annual plants would be highly spatially autocorrelated and that this would be positively linked with the spatial(More)
Validation of Operations Research/Management Science (OR/MS) decision support models is usually performed with the aim of providing the decision makers with sufficient confidence to utilize the model’s recommendations to support their decision-making. OR/MS models for investigation and improvement provide a particularly challenging task as far as validation(More)
Hyperspectral remote sensing serves as an effective tool for estimating foliar nitrogen using a variety of techniques. Vegetation indices (VIs) are a simple means of retrieving foliar nitrogen. Despite their popularity, few studies have been conducted to examine the utility of VIs for mapping canopy foliar nitrogen in a mixed forest context. In this study,(More)
Eldana saccharina Walker (Lepidoptera: Pyralidae) has caused high yield losses in KwaZulu-Natal sugarcane. Early cutting is one of a number of methods being used to reduce losses due to E. saccharina infestations. A cohort based age-structured mathematical model was developed to enable sugarcane growers to simulate the effect of various seasonal conditions(More)
Surface water is one of the constraining resources for herbivore populations in semi-arid regions. Artificial waterpoints are constructed by wildlife managers to supplement natural water supplies, to support herbivore populations. The aim of this paper is to analyse how a landowner may realize his ecological and economic goals by manipulating waterpoints(More)