127 research outputs found

    Farmers’ preferential choice decisions to alternative cassava value chain strands in Morogoro rural district, Tanzania

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    The study was conducted to determine farmers’ preferential choice decision of alternative cassava value chain strands and as well as factors behind such decisions in Morogoro rural District, Tanzania. Factor analysis was first used to reduce and identify the factors (variables for further analysis whereby the factors with highest eigen-value were applied to develop factor scores to measure the attitudinal variables. Results indicate that farmers have positive risk attitude towards participation in the alternative cassava value chain strands for commercialization. A count data model known as Poisson model was applied to determine the factors which influenced this attitude. Results indicated that farm size, experience, female-headed households and land-holding had influenced the farmers’ preferential choice decision. Recommendations for enhancing farmers’ participation in profitable cassava value chain strands are strengthening coordination, provision of improved cassava varieties and introduction of cassava processing technologies.Preferential choice decisions; factor analysis; cassava farmers; risk attitude; Poisson model

    Temporal Modulation of Traveling Waves in the Flow Between Rotating Cylinders With Broken Azimuthal Symmetry

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    The effect of temporal modulation on traveling waves in the flows in two distinct systems of rotating cylinders, both with broken azimuthal symmetry, has been investigated. It is shown that by modulating the control parameter at twice the critical frequency one can excite phase-locked standing waves and standing-wave-like states which are not allowed when the system is rotationally symmetric. We also show how previous theoretical results can be extended to handle patterns such as these, that are periodic in two spatial direction.Comment: 17 pages in LaTeX, 22 figures available as postscript files from http://www.esam.nwu.edu/riecke/lit/lit.htm

    The effect of nitrogen-fertilizer and optimal plant population on the profitability of maize plots in the Wami River sub-basin, Tanzania: A bio-economic simulation approach

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    Maize (Zea mays L.) is the essential staple in sub-Saharan Africa (SSA) and Tanzania in particular; the crop accounts for over 30% of the food production, 20% of the agricultural gross domestic product (GDP) and over 75% of the cereal consumption. Maize is grown under a higher risk of failure due to the over-dependence rain-fed farming system resulting in low income and food insecurity among maize-based farmers. However, many practices, including conservation agriculture, soil and water conservation, resilient crop varieties, and soil fertility management, are suggested to increase cereal productivity in Tanzania. Improving planting density, and the use of fertilizers are the immediate options recommended by Tanzania's government. In this paper, we evaluate the economic feasibility of the improved planting density (optimized plant population) and N-fertilizer crop management practices on maize net returns in semi-arid and sub-humid agro-ecological zones in the Wami River sub-Basin, Tanzania. We introduce a bio-economic simulation model using Monte Carlo simulation procedures to evaluate the economic viability of risky crop management practices so that the decision-maker can make better management decisions. The study utilizes maize yield data sets from two biophysical cropping system models, namely the APSIM and DSSAT. A total of 83 plots for the semi-arid and 85 plots for the sub-humid agro-ecological zones consisted of this analysis. The crop management practices under study comprise the application of 40 kg N-fertilizer/ha and plant population of 3.3 plants/m2. The study finds that the use of improved plant population had the lowest annual net return with fertilizer application fetching the highest return. The two crop models demonstrated a zero probability of negative net returns for farms using fertilizer rates of 40 kg N/ha except for DSSAT, which observed a small probability (0.4%) in the sub-humid area. The optimized plant population presented 16.4% to 26.6% probability of negatives net returns for semi-arid and 14.6% to 30.2% probability of negative net returns for sub-humid zones. The results suggest that the application of fertilizer practices reduces the risks associated with the mean returns, but increasing the plant population has a high probability of economic failure, particularly in the sub-humid zone. Maize sub-sector in Tanzania is projected to continue experiencing a significant decrease in yields and net returns, but there is a high chance that it will be better-off if proper alternatives are employed. Similar studies are needed to explore the potential of interventions highlighted in the ACRP for better decision-making

    Farmers’ preferential choice decisions to alternative cassava value chain strands in Morogoro rural district, Tanzania

    Get PDF
    The study was conducted to determine farmers’ preferential choice decision of alternative cassava value chain strands and as well as factors behind such decisions in Morogoro rural District, Tanzania. Factor analysis was first used to reduce and identify the factors (variables for further analysis whereby the factors with highest eigen-value were applied to develop factor scores to measure the attitudinal variables. Results indicate that farmers have positive risk attitude towards participation in the alternative cassava value chain strands for commercialization. A count data model known as Poisson model was applied to determine the factors which influenced this attitude. Results indicated that farm size, experience, female-headed households and land-holding had influenced the farmers’ preferential choice decision. Recommendations for enhancing farmers’ participation in profitable cassava value chain strands are strengthening coordination, provision of improved cassava varieties and introduction of cassava processing technologies

    Ring-Pattern Dynamics in Smectic-C* and Smectic-C_A* Freely Suspended Liquid Crystal Films

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    Ring patterns of concentric 2pi-solitons in molecular orientation, form in freely suspended chiral smectic-C films in response to an in-plane rotating electric field. We present measurements of the zero-field relaxation of ring patterns and of the driven dynamics of ring formation under conditions of synchronous winding, and a simple model which enables their quantitative description in low polarization DOBAMBC. In smectic C_A* TFMHPOBC we observe an odd-even layer number effect, with odd number layer films exhibiting order of magnitude slower relaxation rates than even layer films. We show that this rate difference is due to much larger spontaneous polarization in odd number layer films.Comment: 4 RevTeX pgs, 4 eps figures, submitted to Phys. Rev. Let

    Agricultural innovation platform as a tool for development oriented research: Lessons and challenges in the formation and operationalization

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    The emergence of Integrated Agricultural Research for Development (IAR4D) presents an opportunity to address any development problem. It involves innovative principles and an integrated research agenda while recognizing the need for greater organizational capacities among stakeholders in agriculture. Operationalization of IAR4D revolves around successful establishment and operation of an Agricultural Innovation Platform (AIP). Agricultural Innovation Platforms are being implemented in Lake Kivu Pilot Learning Site (LKPLS) of the Sub-Saharan Africa Challenge Programme, covering three countries (Uganda, Rwanda and Democratic Republic of Congo) with widely differing social political environments to address agricultural development challenges. This paper presents the processes, general guidelines lessons and experiences pertaining to “good practices” for organising and forming AIPs in the LKPLS. The life of AIPs covers three phases, namely; pre-formation, formation and post formation. The lessons and experiences are shared across 6 stages of AIP formation, namely; Identification of a research and developmental challenge(s), Site selection, Consultative and scoping study, Visioning and Stakeholder analysis, Development of action plans and Implementation of the action plans. Emerging lessons highlight AIPs as grounds and pillars for multi-level, multi-stakeholder interactions to identify, understand and address a complex challenge, concomitant emerging issues and learning towards achieving the agreed vision. Agricultural Innovation Platform formation is a dynamic, highly context specific process that incorporates all essential ingredients for successful innovation at once and provides an opportunity for local innovations to bear while at the same time nourishing on introduced innovations. In AIP formation, the recognition and value of indigenous knowledge and capitalization on prevailing policy, institutional setting and involvement of local leadership is vital. The form, nature and time taken by AIP formation process depends on both the conceptual and local context, quality of facilitation, socio-economic, culture, biophysical, political environment in which a common challenge and/or opportunity is identified and on the capacity of stakeholders to comprehend the Innovation Systems Approach (ISA). The process of AIP formation was faster in creating win-wins when market led. Strong leadership, strategic partnership, information flow, interactions and dealing with recurrent challenges during the AIP formation process are critical in fostering innovations. The major challenges included capacitating the stakeholders in requisite skills and dealing with persistent “handout-syndrome”
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