307 research outputs found

    Soil and water conservation strategies and impact on sustainable livelihood in Cape Verde – Case study of Ribeira Seca watershed

    Get PDF
    Cape Verde, located off the coast of Senegal in western Africa, is a volcanic archipelago where a combination of human, climatic, geomorphologic and pedologic factors has led to extensive degradation of the soils. Like other Sahelian countries, Cape Verde has suffered the effects of desertification through the years, threatening the livelihood of the islands population and its fragile environment. In fact, the steep slopes in the ore agricultural islands, together with semi-arid and arid environments, characterized by an irregular and poorly distributed rainy season, with high intensity rainfall events, make dryland production a challenge. To survive in these fragile conditions, the stabilization of the farming systems and the maintenance of sustainable yields have become absolute priorities, making the islands an erosion control laboratory. Soil and water conservation strategies have been a centerpiece of the government0s agricultural policies for the last half century. Aiming to maintain the soil in place and the water inside the soil, the successive governments of Cape Verde have implemented a number of soil and water conservation techniques, the most common ones being terraces, half moons, live barriers, contour rock walls, contour furrows and microcatchments, check dams and reforestation with drought resistant species. The soil and water conservation techniques implemented have contributed to the improvement of the economical and environmental conditions of the treated landscape, making crop production possible, consequently, improving the livelihood of the people living on the islands. In this paper, we survey the existing soil and water conservation techniques, analyze their impact on the livelihood condition of the population through a thorough literature review and field monitoring using a semi-quantitative methodology and evaluate their effectiveness and impact on crop yield in the Ribeira Seca watershed. A brief discussion is given on the cost and effectiveness of the techniques to reduce soil erosion and to promote rainfall infiltration. Finally, we discuss the critical governance factors that lead to the successful implementation of such strategy in a country with scarce natural resources

    Upper- and mid-mantle interaction between the Samoan plume and the Tonga-Kermadec slabs

    Get PDF
    Mantle plumes are thought to play a key role in transferring heat from the core\u2013mantle boundary to the lithosphere, where it can significantly influence plate tectonics. On impinging on the lithosphere at spreading ridges or in intra-plate settings, mantle plumes may generate hotspots, large igneous provinces and hence considerable dynamic topography. However, the active role of mantle plumes on subducting slabs remains poorly understood. Here we show that the stagnation at 660 km and fastest trench retreat of the Tonga slab in Southwestern Pacific are consistent with an interaction with the Samoan plume and the Hikurangi plateau. Our findings are based on comparisons between 3D anisotropic tomography images and 3D petrological-thermo-mechanical models, which self-consistently explain several unique features of the Fiji\u2013Tonga region. We identify four possible slip systems of bridgmanite in the lower mantle that reconcile the observed seismic anisotropy beneath the Tonga slab (VSH4VSV) with thermo-mechanical calculations

    Better before worse trajectories in food systems? An investigation of synergies and trade-offs through climate-smart agriculture and system dynamics

    Get PDF
    Food systems face multiple challenges simultaneously: provision to a growing population, adaptation to more extreme and frequent climate change risks, and reduction of their considerable greenhouse gas (GHG) emissions. Food system interventions and policies give rise to synergies and trade-offs that emerge over time due to the dynamic nature and interconnections of system elements. Analysis of an entire food system is necessary to identify synergies that bring simultaneous benefits and mitigate trade-offs, both short- and long-term. OBJECTIVE: Our study aims to inform the sustainable transformation of food systems by identifying short- and long-term synergies and trade-offs in the climate-smart village (CSV) Lawra-Jirapa in northern Ghana under the current practices, technologies, policies, and trends of population growth, extreme events, and climate change impacts

    Are Small GTPases Signal Hubs in Sugar-Mediated Induction of Fructan Biosynthesis?

    Get PDF
    External sugar initiates biosynthesis of the reserve carbohydrate fructan, but the molecular processes mediating this response remain obscure. Previously it was shown that a phosphatase and a general kinase inhibitor hamper fructan accumulation. We use various phosphorylation inhibitors both in barley and in Arabidopsis and show that the expression of fructan biosynthetic genes is dependent on PP2A and different kinases such as Tyr-kinases and PI3-kinases. To further characterize the phosphorylation events involved, comprehensive analysis of kinase activities in the cell was performed using a PepChip, an array of >1000 kinase consensus substrate peptide substrates spotted on a chip. Comparison of kinase activities in sugar-stimulated and mock(sorbitol)-treated Arabidopsis demonstrates the altered phosphorylation of many consensus substrates and documents the differences in plant kinase activity upon sucrose feeding. The different phosphorylation profiles obtained are consistent with sugar-mediated alterations in Tyr phosphorylation, cell cycling, and phosphoinositide signaling, and indicate cytoskeletal rearrangements. The results lead us to infer a central role for small GTPases in sugar signaling

    Relationship between polarities of antibiotic and polymer matrix on nanoparticle formulations based on aliphatic polyesters

    Get PDF
    In the field of nanomedicine, nanoparticles are developed to target antibiotics to sites of bacterial infection thus enabling adequate drug exposure and decrease development of resistant bacteria. In the present study, we investigated the encapsulation of two antibiotics with different polarity into different PEGylated polymeric nanoparticles based on aliphatic polyesters, to obtain a better understanding of critical factors determining encapsulation and release. The nanoparticles were prepared from diblock copolymers comprising of a poly(ethylene glycol) block attached to an aliphatic polyester block of varying polarity: poly(lactic-co-glycolic acid) (mPEG-PLGA), poly(lactic-co-hydroxymethyl glycolic acid) (mPEG-PLHMGA) and poly(lactic-co-benzyloxymethyl glycolic acid) (mPEG-PLBMGA). Hydrophobic bedaquiline and hydrophilic vancomycin were encapsulated via single and double-emulsion solvent evaporation techniques, respectively. Encapsulation, degradation and release studies at physiological simulating conditions were performed. Drug polarity and preparation techniques influenced encapsulation efficiency into polymer nanoparticles, giving almost complete encapsulation of bedaquiline and approx. 30% for vancomycin independent of the polymer type. The nonpolar bedaquiline showed a predominantly diffusion-controlled release independent of polymer composition. However, polar vancomycin was released by a combination of diffusion and polymer degradation, which was significantly affected by polymer composition, the most hydrophilic polymer displaying the fastest release

    AN EROSION MODEL AS A TOOL FOR FARMERS INVOLVEMENT FOR DEFINING LAND USE STRATEGIES IN FIJI AND SAMOA

    Get PDF
    Abstract South Pacific islands are under increasing pressure, and the threats are primarily from human interactions. The arrival of western values in the South Pacific resulted in forest depletion and intensive agricultural production systems, which have led to increasing damage to the environment, while bringing relatively few benefits to the resource owners. The pressure to which natural resources have been subjected by these development efforts, and the substantial and sometimes disastrous degradation and depletion which have occurred, has begun to focus the attention of communities on the need to implement sustainable management of those remaining resources. At present, crop production systems practiced in South Pacific Island States range from traditional to high input production systems. The majority of the farmers in Fiji and Samoa fall within these two extremes in what will be termed moderate input production systems. The physically based model LISEM is used to quantify the losses of soil and water in two small agricultural catchments in Samoa and Fiji. To be able to communicate directly with the farmers about the effects of proposed alternative land use on the spot calculation-results will be presented during village meetings. Calibration of the model showed that results for calculated discharge matches the measured values. In both catchments, demonstration areas of alternative land use strategies are implemented. Modeling tools will be used in the negotiation process with local stakeholders to come to feasible, reliable and acceptable alternative land management and land use strategies to increase people's welfare and reduce soil degradation and environmental pollution. Additional Keywords: soil erosion, conservation, modeling, participation Introduction The increasing population pressures and emerging trends of socio-economic marginalization or rural populations are putting a heavy strain on the delicate ecosystems of the Pacific Island Countries. In response to the rapidly increasing demands for food, Pacific farmers abandon traditional farming systems to adopt high input commercial production methods for short term gains, which are often unsustainable, in particular on sloping lands. The resulting erosion causes rapid depletion of soil fertility as well as pollution of ground-and open-water systems. The CROPPRO project aims to provide assistance to Pacific Island countries with the development of integrated farming approaches for sustainable crop production in environmentally constrained systems. The project specifically addresses the relation between agricultural activities and the surrounding environment, and focuses on the development of tailor-made farming approaches for major crop/soil units aiming at maximising agricultural production and minimising environmental deterioration. Special attention will be paid to knowledge transfer and participatory, culture-sensitive training for stakeholders and end-users. The project is funded by the EU, INO-DC and the Ministry of Agriculture, Nature and Fisheries of The Netherland

    Сучасний стан і проблеми управління залізничним транспортом України

    Get PDF
    Проаналізовано стан і тенденції розвитку залізничного транспорту. Розглянуті основні завдання державного регулювання галузі.Проанализировано состояние и тенденции развития железнодорожного транспорта. Рассмотренны основные задания государственного регулирования отрасли.The condition and trends of railway transport has been anilized. The main tasks of state regulation of railway transport has been considereted
    corecore