86 research outputs found

    The Role of Food from Natural Resources in Reducing Vulnerability to Poverty: A Case Study from Zimbabwe

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    Vulnerability to poverty is a major problem in the rural areas of Sub Saharan Africa. Rural Households are confronted with various covariate and idiosyncratic shocks and are often severely constrained in coping with such events. They frequently resort to food from natural resources such as indigenous fruits during times of crisis. The availability of such food sources is increasingly at risk due to deforestation and biodiversity loss. The objective of this paper is to quantify the contribution of indigenous fruit trees towards reducing vulnerability to food insecurity and poverty. The methodology used is a multi-period stochastic household income model. The data were collected in a case study in Zimbabwe using detailed monthly income and expenditure records of a sample of 39 rural households in two areas. The two regions differ in their agricultural system. In one area horticulture, off-farm activities and exotic fruits are a major source of income while in the other area indigenous fruits are a more important source of income. This paper concentrates on the latter area. Model calculations show that rural households in Zimbabwe are highly vulnerable to seasonal fluctuations in income and therefore a critical period where households run high risk of being food insecure can be identified. While indigenous fruits, as a low cost 1 International Centre of Insect Physiology and Ecology (ICIPE), Nairobi, Kenya, [email protected] (for merly 2 & 3). 2 Development and Agricultural Economics, Faculty of Econo mics and Business Administration, Hannover University, Germany. 3 World Agrofore stry Centre (ICRAF), Lilongwe, Malawi. natural resource, can facilitate income-smoothing, the role of other sources of income must not be neglected. The paper concludes that diversified season-specific income generating portfolios must be designed of which indigenous fruit trees have a role to play.Vulnerability, poverty, food security, seasonal fluctuations, wild food resources, Zimbabwe, Food Security and Poverty,

    Femoral fracture following knee ligament reconstruction surgery due to an unpredictable complication of bioabsorbable screw fixation: a case report and review of literature

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    We report an unusual case of femoral fracture from minimal trauma, due to the rapid disappearance of a bioabsorbable interference screw used for reconstruction of the posterolateral corner of the knee. The literature on bone tunnel fractures following knee ligament reconstruction surgery is also reviewed

    Platelet Function in Acute Experimental Pancreatitis

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    Acute pancreatitis (AP) is characterized by disturbances of pancreatic microcirculation. It remains unclear whether platelets contribute to these perfusion disturbances. The aim of our study was to investigate platelet activation and function in experimental AP. Acute pancreatitis was induced in rats: (1) control (n = 18; Ringer’s solution), (2) mild AP (n = 18; cerulein), and (3) severe AP (n = 18; glycodeoxycholic acid (GDOC) + cerulein). After 12 h, intravital microscopy was performed. Rhodamine-stained platelets were used to investigate velocity and endothelial adhesion in capillaries and venules. In addition, erythrocyte velocity and leukocyte adhesion were evaluated. Serum amylase, thromboxane A2, and histology were evaluated after 24 h in additional animals of each group. Results showed that 24 h after cerulein application, histology exhibited a mild AP, whereas GDOC induced severe necrotizing AP. Intravital microscopy showed significantly more platelet–endothelium interaction, reduced erythrocyte velocity, and increased leukocyte adherence in animals with AP compared to control animals. Thromboxane levels were significantly elevated in all AP animals and correlated with the extent of platelet activation and severity of AP. In conclusion, platelet activation plays an important role in acute, especially necrotizing, pancreatitis. Mainly temporary platelet–endothelium interaction is observed during mild AP, whereas severe AP is characterized by firm adhesion with consecutive coagulatory activation and perfusion failure

    Complex Odor from Plants under Attack: Herbivore's Enemies React to the Whole, Not Its Parts

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    Background: Insect herbivory induces plant odors that attract herbivores ’ natural enemies. Assuming this attraction emerges from individual compounds, genetic control over odor emission of crops may provide a rationale for manipulating the distribution of predators used for pest control. However, studies on odor perception in vertebrates and invertebrates suggest that olfactory information processing of mixtures results in odor percepts that are a synthetic whole and not a set of components that could function as recognizable individual attractants. Here, we ask if predators respond to herbivoreinduced attractants in odor mixtures or to odor mixture as a whole. Methodology/Principal Findings: We studied a system consisting of Lima bean, the herbivorous mite Tetranychus urticae and the predatory mite Phytoseiulus persimilis. We found that four herbivore-induced bean volatiles are not attractive in pure form while a fifth, methyl salicylate (MeSA), is. Several reduced mixtures deficient in one component compared to the full spider-mite induced blend were not attractive despite the presence of MeSA indicating that the predators cannot detect this component in these odor mixtures. A mixture of all five HIPV is most attractive, when offered together with the noninduced odor of Lima bean. Odors that elicit no response in their pure form were essential components of the attractive mixture. Conclusions/Significance: We conclude that the predatory mites perceive odors as a synthetic whole and that th

    Extracellular Fibrils of Pathogenic Yeast Cryptococcus gattii Are Important for Ecological Niche, Murine Virulence and Human Neutrophil Interactions

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    Cryptococcus gattii, an emerging fungal pathogen of humans and animals, is found on a variety of trees in tropical and temperate regions. The ecological niche and virulence of this yeast remain poorly defined. We used Arabidopsis thaliana plants and plant-derived substrates to model C. gattii in its natural habitat. Yeast cells readily colonized scratch-wounded plant leaves and formed distinctive extracellular fibrils (40–100 nm diameter ×500–3000 nm length). Extracellular fibrils were observed on live plants and plant-derived substrates by scanning electron microscopy (SEM) and by high voltage- EM (HVEM). Only encapsulated yeast cells formed extracellular fibrils as a capsule-deficient C. gattii mutant completely lacked fibrils. Cells deficient in environmental sensing only formed disorganized extracellular fibrils as apparent from experiments with a C. gattii STE12α mutant. C. gattii cells with extracellular fibrils were more virulent in murine model of pulmonary and systemic cryptococcosis than cells lacking fibrils. C. gattii cells with extracellular fibrils were also significantly more resistant to killing by human polymorphonuclear neutrophils (PMN) in vitro even though these PMN produced elaborate neutrophil extracellular traps (NETs). These observations suggest that extracellular fibril formation could be a structural adaptation of C. gattii for cell-to-cell, cell-to-substrate and/or cell-to- phagocyte communications. Such ecological adaptation of C. gattii could play roles in enhanced virulence in mammalian hosts at least initially via inhibition of host PMN– mediated killing

    Brevicoryne brassicae aphids interfere with transcriptome responses of Arabidopsis thaliana to feeding by Plutella xylostella caterpillars in a density‑dependent manner

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    Plants are commonly attacked by multiple herbivorous species. Yet, little is known about transcriptional patterns underlying plant responses to multiple insect attackers feeding simultaneously. Here, we assessed= transcriptomic responses of Arabidopsis thaliana plants to simultaneous feeding by Plutella xylostella caterpillars and Brevicoryne brassicae aphids in comparison to plants infested by P. xylostella caterpillars alone, using microarray analysis. We particularly investigated how aphid feeding interferes with the transcriptomic response to P. xylostella caterpillars and whether this interference is dependent on aphid density and time since aphid attack. Various JA-responsive genes were up-regulated in response to feeding by P. xylostella caterpillars. The additional presence of aphids, both at low and high densities, clearly affected the transcriptional plant response to caterpillars. Interestingly, some important modulators of plant defense signalling, including WRKY transcription factor genes and ABA-dependent genes, were differentially induced in response to simultaneous aphid feeding at low or high density compared with responses to P. xylostella caterpillars feeding alone. Furthermore, aphids affected the P. xylostella-induced transcriptomic response in a density dependent manner, which caused an acceleration in plant response against dual insect attack at high aphid density compared to dual insect attack at low aphid density. In conclusion, our study provides evidence that aphids influence the caterpillar-induced transcriptional response of A. thaliana in a density-dependent manner. It highlights the importance of addressing insect density to understand how plant responses to single attackers interfere with responses to other attackers and thus underlines the importance of the dynamics of transcriptional plant responses to multiple herbivory

    The Role of Food from Natural Resources in Reducing Vulnerability to Poverty: A Case Study from Zimbabwe

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    Vulnerability to poverty is a major problem in the rural areas of Sub Saharan Africa. Rural Households are confronted with various covariate and idiosyncratic shocks and are often severely constrained in coping with such events. They frequently resort to food from natural resources such as indigenous fruits during times of crisis. The availability of such food sources is increasingly at risk due to deforestation and biodiversity loss. The objective of this paper is to quantify the contribution of indigenous fruit trees towards reducing vulnerability to food insecurity and poverty. The methodology used is a multi-period stochastic household income model. The data were collected in a case study in Zimbabwe using detailed monthly income and expenditure records of a sample of 39 rural households in two areas. The two regions differ in their agricultural system. In one area horticulture, off-farm activities and exotic fruits are a major source of income while in the other area indigenous fruits are a more important source of income. This paper concentrates on the latter area. Model calculations show that rural households in Zimbabwe are highly vulnerable to seasonal fluctuations in income and therefore a critical period where households run high risk of being food insecure can be identified. While indigenous fruits, as a low cost 1 International Centre of Insect Physiology and Ecology (ICIPE), Nairobi, Kenya, [email protected] (for merly 2 & 3). 2 Development and Agricultural Economics, Faculty of Econo mics and Business Administration, Hannover University, Germany. 3 World Agrofore stry Centre (ICRAF), Lilongwe, Malawi. natural resource, can facilitate income-smoothing, the role of other sources of income must not be neglected. The paper concludes that diversified season-specific income generating portfolios must be designed of which indigenous fruit trees have a role to play
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