12 research outputs found

    Deagrarianisation and forest revegetation in a biodiversity hotspot on the Wild Coast, South Africa

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    Deagraianisation is a worldwide phenomenon with widespread social, ecological and economic effects yet with little consensus on the local or higher level causes. There have been contested views on the causes and consequences of deagrarianisation on South Africa’s Wild Coast, which is an international biodiversity hotspot. Using GIS, household interviews and ecological sampling, we compared the perspectives of current and former cultivators as to why some have abandoned farming, whilst also tracking the uses and woody plant cover and composition of fields abandoned at different periods. The GIS analysis showed that field abandonment had been ongoing over several decades, with a decline from 12.5 % field cover in 1961 to 2.7 % in 2009. The area of forests and woodlands almost doubled in the corresponding period. There was a distinct peak in field abandonment during the time of political transition at the national level in the early 1990s. This political change led to a decrease in government support for livestock farming, which in turn resulted in reduced animal draught power at the household and community level, and hence reduced cropping. The study showed it is largely the wealthier households that have remained in arable agriculture and that the poorer households have abandoned farming. The abandoned fields show a distinct trend of increasing woody biomass and species richness with length of time since abandonment, with approximately three woody plant species added per decade. Most local respondents dislike the increases in forest and woodland extent and density because of anxiety about wild animals causing harm to crops and even humans, and the loss of an agricultural identity to livelihoods and the landscape

    Hemodynamics: An Introduction

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    International audienceThe cardiovascular transport circuit is involved in both mass and heat transfer. It carries blood cells as well as oxygen and nutrients to cells of the body’s organs through the perfusing systemic arterial bed and wastes produced by working cells to their final destinations through draining veins. Blood flows throughout the body in the vasculature due to a pressure difference between the ventricular outlet and atrial inlet. Blood is propelled in the systemic and pulmonary circulation by the synchronized action of the left and right apposed cardiac pumps, respectively. Hemodynamics is related to the flow features in the heart and blood vessels, in normal and pathological conditions, in particular the pressure–flow relations and transport of substances by blood to given target organs. It can be required in therapy planning and optimization
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