867 research outputs found

    Micro-level practices to adapt to climate change for African small-scale farmers:

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    This paper discusses micro-level practices for adapting to climate change that are available to small-scale farmers in Africa. The analysis is based on a review of 17 studies about practices that boost small-scale farmers' resilience or reduce their vulnerability to observed or expected changes in climate; it includes data from more than 16 countries in Africa, the Americas, Europe, and Asia. The review shows that African smallholders are already using a wide variety of creative practices to deal with climate risks; these can be further adjusted to the challenge of climate change by planned adaptation programs. We found 104 different practices relevant to climate change adaptation and organized them in five categories: farm management and technology; farm financial management; diversification on and beyond the farm; government interventions in infrastructure, health, and risk reduction; and knowledge management, networks, and governance. We conclude that adaptation policies should complement farmers' autonomous response to climate change through the development of new drought-resistant varieties and improved weather forecasts, the provision of financial services, improvement of rural transportation infrastructure, investments in public healthcare and public welfare programs, and policies that improve local governance and coordinate donor activities.Climate change, adaptation practices, content analysis, Small-scale farmers, climate risks, Farm management, diversification, risk reduction, government interventions, public welfare programs

    Particle creation and annihilation at interior boundaries:One-dimensional models

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    We describe creation and annihilation of particles at external sources in one spatial dimension in terms of interior-boundary conditions (IBCs). We derive explicit solutions for spectra, (generalised) eigenfunctions, as well as Green functions, spectral determinants, and integrated spectral densities. Moreover, we introduce a quantum graph version of IBC-Hamiltonians.Comment: 32 page

    Intervention options for small-scale family poultry development in south-eastern Madagascar: an expert survey

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    The diets of resource-poor farmers in the Atsimo Atsinanana (AA) region of south-eastern Madagascar have limited diversity and are low in animal protein. Although poultry farming is widespread, productivity is low, and consumption of eggs is uncommon. To enable effective development interventions targeting poultry value chains, this study pursues two goals: (i) to describe current challenges in small-scale poultry rearing and egg consumption in AA, and (ii) to explore viable options for promoting poultry production. We employ a survey approach, carrying out semi-structured interviews with 16 international and 12 local key informants (KIs) on small-scale poultry development. We find that poultry production in AA is critically constrained by high mortality due to diseases and predation, poor husbandry, and lack of veterinary services. The major health constraint is the Newcastle disease. Given the high mortality rates and low egg-laying potential of local chicken breeds, only small numbers of eggs are consumed, as farmers prioritise hatching. The main identified solutions include improvements in veterinary health and animal husbandry. KIs emphasised the development of animal health support services, including village vaccinators, upgrading feed with locally accessible protein sources, and the need for biosecure housing. Furthermore, training for farmers on poultry management, marketing, and vaccinations was suggested, in addition to creating awareness about the nutritional benefits of poultry products. Our findings are relevant to local development practitioners, as achieving food and nutrition security requires a multifaceted approach that fits local conditions. Our study provides actionable recommendations for improving small-scale family poultry production in AA.

    Reducing Edible Oil Import Dependency in Tanzania

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    Reducing food imports and promoting domestically produced food commodities are long-standing goals for policymakers and other stakeholders in sub-Saharan African countries. For instance, Tanzania, after a long period of dependency on imported food commodities, such as sugar and edible oils, intends to meet its demand for these commodities through domestic production by transforming its agriculture sector to achieve this goal. Applying a general computable equilibrium (CGE) model, this study determines the multiplier effects of technological progress that is assumed to foster domestic edible oilseed crop production, other crops, and Tanzania’s economy in general. Findings from the model establish an increase in domestic production not only for the edible oilseed crops but also for other commodities from other sectors of the economy. In addition, there is a decrease in prices on domestically produced commodities sold in the domestic market, and an increase in disposable income is predicted for all rural and urban households, as well as government revenues. Based on model results, we recommend that the Tanzanian government invests in technological progress and interventions that increase production in sectors such as agriculture, where it has a comparative advantage. Interventions that increase smallholder farmer’s production, such as the use of improved seed and other modern technologies that reduce costs of production, are critical for reducing food imports and improving food security.Peer Reviewe

    Tariff Impact on Industrialization in Tanzania: Evidence from Edible Oil Sub-Sector

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    The research is financed by the Federal Ministry of Food and Agriculture under the auspices of the Federal Office for Agriculture and Food, Germany Abstract Developing countries implement protectionist policies like imposing tariffs, with the aim of promoting domestic production. This study assesses the impact of the imposed tariffs on edible oil on Tanzania’s economy using a recursive dynamic computable general equilibrium model (CGE). Findings from this study show that implementing the tariff intervention on the dibble oil sub-sector has two principle outcomes; first, it triggers domestic producers to supply more due to the rise in demand and prices for the commodities, thus increases domestic production to meet demand; second, it reduces imports, consequently, decreasing citizens’ welfare by limiting the availability and access options from imported commodities. Protectionist policies, when solely used as a solution to increase domestic production in a sector that is inefficient in terms of productivity, creates a supply deficit in the market, thus reducing consumers’ welfare. Therefore, to improve sustainability and increase industrial competitiveness, it is imperative to promote policies and interventions that target increasing productivity. Interventions, like the use of improved seed and other modern technologies, that reduce costs of production are critical as commodities will be sold at a slightly competitive premium or the same prices as imported commodities. Keywords: Tariff; Industrialization; Edible oil; Recursive dynamic CGE; Tanzania DOI: 10.7176/JESD/10-10-02 Publication date:May 31st 201

    Micro-level Practices to Adapt to Climate Change for African Small-scale Farmers

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    This paper discusses micro-level practices for adapting to climate change that are available to small-scale farmers in Africa. The analysis is based on a review of 17 studies about practices that boost small-scale farmersÂż resilience or reduce their vulnerability to observed or expected changes in climate; it includes data from more than 16 countries in Africa, the Americas, Europe, and Asia. The review shows that African smallholders are already using a wide variety of creative practices to deal with climate risks; these can be further adjusted to the challenge of climate change by planned adaptation programs. We found 104 different practices relevant to climate change adaptation and organized them in five categories: farm management and technology; farm financial management; diversification on and beyond the farm; government interventions in infrastructure, health, and risk reduction; and knowledge management, networks, and governance. We conclude that adaptation policies should complement farmersÂż autonomous response to climate change through the development of new drought-resistant varieties and improved weather forecasts, the provision of financial services, improvement of rural transportation infrastructure, investments in public healthcare and public welfare programs, and policies that improve local governance and coordinate donor activities.JRC.DG.J.5-Agriculture and Life Sciences in the Econom

    Temporal dissipative solitons in time-delay feedback systems

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    Localized states are a universal phenomenon observed in spatially distributed dissipative nonlinear systems. Known as dissipative solitons, auto-solitons, spot or pulse solutions, these states play an important role in data transmission using optical pulses, neural signal propagation, and other processes. While this phenomenon was thoroughly studied in spatially extended systems, temporally localized states are gaining attention only recently, driven primarily by applications from fiber or semiconductor lasers. Here we present a theory for temporal dissipative solitons (TDS) in systems with time-delayed feedback. In particular, we derive a system with an advanced argument, which determines the profile of the TDS. We also provide a complete classification of the spectrum of TDS into interface and pseudo-continuous spectrum. We illustrate our theory with two examples: a generic delayed phase oscillator, which is a reduced model for an injected laser with feedback, and the FitzHugh-Nagumo neuron with delayed feedback. Finally, we discuss possible destabilization mechanisms of TDS and show an example where the TDS delocalizes and its pseudo-continuous spectrum develops a modulational instability.Comment: 5 pages, 4 figures, submitted (revision) supplementary material available at https://doi.org/10.6084/m9.figshare.8269757 source code for reproducing figures 1a,b, 2a, 3a,b,c available at https://doi.org/10.6084/m9.figshare.824167

    Can Tanzania's adaptation measures prevent future maize yield decline? A simulation study from Singida region

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    Cereal crop production in sub-Saharan Africa has not achieved the much-needed increase in yields to foster economic development and food security. Maize yields in the region's semi-arid agroecosystems are constrained by highly variable rainfall, which may be worsened by climate change. Thus, the Tanzanian government has prioritized agriculture as an adaptation sector in its intended nationally determined contribution, and crop management adjustments as a key investment area in its Agricultural Sector Development Programme. In this study, we investigated how future changes in maize yields under different climate scenarios can be countered by regional adjusted crop management and cultivar adaptation strategies. A crop model was used to simulate maize yields in the Singida region of Tanzania for the baseline period 1980-2012 and under three future climate projections for 2020-2060 and 2061-2099. Adaptation strategies to improve yields were full irrigation, deficit irrigation, mulch and nitrogen addition and another cultivar. According to our model results, increase in temperature is the main driver of future maize yield decline. Increased respiration and phenological development were associated with lower maize yields of 16% in 2020-2060 and 20% in 2061-2099 compared to the 1980-2012 baseline. Surprisingly, none of the management strategies significantly improved yields; however, a different maize variety that was tested as an alternative coping strategy performed better. This study suggests that investment in accessibility of improved varieties and investigation of maize traits that have the potential to perform well in a warmer future are better suited for sustaining maize production in the semi-arid region than adjustments in crop management

    Temporal dissipative solitons in time-delay feedback systems

    Get PDF
    Localized states are a universal phenomenon observed in spatially distributed dissipative nonlinear systems. Known as dissipative solitons, auto-solitons, spot or pulse solitons, these states play an important role in data transmission using optical pulses, neural signal propagation, and other processes. While this phenomenon was thoroughly studied in spatially extended systems, temporally localized states are gaining attention only recently, driven primarily by applications from fiber or semiconductor lasers. Here we present a theory for temporal dissipative solitons (TDS) in systems with time-delayed feedback. In particular, we derive a system with an advanced argument, which determines the profile of the TDS. We also provide a complete classification of the spectrum of TDS into interface and pseudo-continuous spectrum. We illustrate our theory with two examples: a generic delayed phase oscillator, which is a reduced model for an injected laser with feedback, and the FitzHugh--Nagumo neuron with delayed feedback. Finally, we discuss possible destabilization mechanisms of TDS and show an example where the TDS delocalizes and its pseudo-continuous spectrum develops a modulational instability

    Robustness during Aging—Molecular Biological and Physiological Aspects

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    Understanding the process of aging is still an important challenge to enable healthy aging and to prevent age-related diseases. Most studies in age research investigate the decline in organ functionality and gene activity with age. The focus on decline can even be considered a paradigm in that field. However, there are certain aspects that remain surprisingly stable and keep the organism robust. Here, we present and discuss various properties of robust behavior during human and animal aging, including physiological and molecular biological features, such as the hematocrit, body temperature, immunity against infectious diseases and others. We examine, in the context of robustness, the different theories of how aging occurs. We regard the role of aging in the light of evolution
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