Parametric and Non-Parametric Estimation of Soil Conservation Impact on Productivity in the Northwestern Ethiopian Highlands

The impact of fanya juu bunds on productivity in a high rainfall area in the Ethiopian highlands is analyzed based on data from a cross section household survey with multiple plot observations per household. The results from parametric and non-parametric analysis indicated that productivity from conserved plots was lower than from non-conserved plots. The Oaxaca-Blinder productivity decomposition results showed that there was little difference in plot characteristics between conserved and non-conserved plots, however the returns to those characteristics were higher for non-conserved plots. The sensitivity analysis, increasing fodder grass production on bunds, suggests that there are possibilities to make conserved plots as productive as non-conserved ones. The findings imply that fanya juu bunds may be inappropriate to the local conditions under the existing condition. Farmers in the study area reported that these bunds h ave problem of water-logging, reduce land available for production, and create difficulties in turning the ox-drawn plough due to narrow bund sp acing. Apart from these, there is no attempt made to integrate these bunds with soil fertility management techniques. Overall, these results yield important lessons for future design of conservation technologies that have both physical and economic benefits as well as that are best suited to the local conditions.Yield decomposition, soil conservation, switching regression, stochastic dominance analysis, matching methods, Land Economics/Use, Productivity Analysis, C21, C23, Q12, Q15, Q16,

Adoption and Impact of Improved Groundnut Varieties on Rural Poverty: Evidence from Rural Uganda

This paper evaluates the ex-post impact of adopting improved groundnut varieties on crop income and rural poverty in rural Uganda. The study utilizes cross-sectional farm household data collected in 2006 in seven districts of Uganda. We estimated the average adoption premium using propensity score matching (PSM), poverty dominance analysis tests, and a linear regression model to check robustness of results. Poverty dominance analysis tests and linear regression estimates are based on matched observations of adopters and non-adopters obtained from the PSM. This helped us estimate the true welfare effect of technology adoption by controlling for the role of selection problem on production and adoption decisions. Furthermore, we checked covariate balancing with a standardized bias measure and sensitivity of the estimated adoption effect to unobserved selection bias, using the Rosenbaum bounds procedure. The paper computes income-based poverty measures and investigates their sensitivity to the use of different poverty lines. We found that adoption of improved groundnut technologies has a significant positive impact on crop income and poverty reduction. These results are not sensitive to unobserved selection bias; therefore, we can be confident that the estimated adoption effect indicates a pure effect of improved groundnut technology adoption.groundnut technology adoption, crop income, poverty alleviation, propensity score matching, switching regression, stochastic dominance, Rosenbaum bounds, Uganda

Comparison of the heat transfer efficiency of nanofluids

The continuously increasing power involved in many applications, coupled with the very small size of a number of component devices, is pushing the technical community to look for more efficient heat transfer systems, to remove the heat generated and keep the system under controlled operating conditions. In particular, significant interest has been devoted to the use of the so-called nanofluids, obtained by suspending nano-sized particles in conventional heat transfer liquids. According to some literature, these suspensions present enhanced heat transfer capabilities, without the inconveniencies of particles settlement and clogging of the channels encountered using larger particles. However, other results show that the actual improvement in the heat transfer efficiency may depend on the adopted working conditions and on the reference parameters (fluid velocity, Reynolds number, pressure drop, etc.) assumed to compare the performances of the nanoparticles suspensions with those of the clear thermal fluid. In the present work heat transfer experiments were carried out on a number of nanofluids systems, varying the type and the concentration of the nanoparticles, and the fluid dynamic regime. The investigated suspensions gave rise to heat transfer coefficients different from those of their respective clear thermal fluid, the thermal efficiency being higher or lower, depending on the fluid dynamic parameter used as a base for comparing the systems. Generally speaking, in most cases nanofluids may give an advantage from the heat transfer point of view only when the conditions are unfavorable for the traditional thermal fluid

Sustainable Agricultural Practices and Agricultural Productivity in Ethiopia: Does Agroecology Matter?

This paper uses data from household- and plot-level surveys conducted in the highlands of the Tigray and Amhara regions of Ethiopia to examine the contribution of sustainable land-management practices to net values of agricultural production in areas with low- and high-agricultural potential. A combination of parametric and nonparametric estimation techniques is used to check result robustness. Both techniques consistently predict that minimum tillage is superior to commercial fertilizers—as are farmers’ traditional practices without use of commercial fertilizers—in enhancing crop productivity in the low-agricultural potential areas. In the high-agricultural potential areas, by contrast, use of commercial fertilizers is superior to both minimum tillage and farmers’ traditional practices without commercial fertilizers. The results are found to be insensitive to hidden bias. Our findings imply a need for careful agroecological targeting when developing, promoting, and scaling up sustainable land-management practices.agricultural productivity, commercial fertilizer, Ethiopia, low and high agricultural potential, minimum tillage, propensity score matching, switching regression

Urban Energy Transition and Technology Adoption: The Case of Tigrai, Northern Ethiopia

Dependency of urban Ethiopian households on rural areas for about 85 percent of their fuel needs is a significant cause of deforestation and forest degradation, resulting in growing fuel scarcity and higher firewood prices. One response to reducing the pressure on rural lands is for urban households to switch fuel sources (from fuelwood to electricity, for example) to slow deforestation and forest degradation and reduce indoor air pollution. However, such an energy transition is conditioned on the adoption of appropriate cooking appliances or stove technologies by the majority of users. This paper investigates urban energy transition and technology adoption conditions using a dataset of 350 urban households in Tigrai, in northern Ethiopia. Results suggest that the transition to electricity is affected by households adopting the electric mitad cooking appliance, which in turn is influenced by the level of education and income, among other things.urban energy transition, electric mitad cooking appliance, technology adoption, bivariate probit, Tigrai, Ethiopia

Towards the Dependence on Parameters for the Solution of the Thermostatted Kinetic Framework

A complex system is a system involving particles whose pairwise interactions cannot be composed in the same way as in classical Mechanics, i.e., the result of interaction of each particle with all the remaining ones cannot be expressed as a sum of its interactions with each of them (we cannot even know the functional dependence of the total interaction on the single interactions). Moreover, in view of the wide range of its applications to biologic, social, and economic problems, the variables describing the state of the system (i.e., the states of all of its particles) are not always (only) the usual mechanical variables (position and velocity), but (also) many additional variables describing e.g., health, wealth, social condition, social rôle . . . , and so on. Thus, in order to achieve a mathematical description of the problems of everyday’s life of any human society, either at a microscopic or at a macroscpoic scale, a new mathematical theory (or, more precisely, a scheme of mathematical models), called KTAP, has been devised, which provides an equation which is a generalized version of the Boltzmann equation, to describe in terms of probability distributions the evolution of a non-mechanical complex system. In connection with applications, the classical problems about existence, uniqueness, continuous dependence, and stability of its solutions turn out to be particularly relevant. As far as we are aware, however, the problem of continuous dependence and stability of solutions with respect to perturbations of the parameters expressing the interaction rates of particles and the transition probability densities (see Section The Basic Equations has not been tackled yet). Accordingly, the present paper aims to give some initial results concerning these two basic problems. In particular, Theorem 2 reveals to be stable with respect to small perturbations of parameters, and, as far as instability of solutions with respect to perturbations of parameters is concerned, Theorem 3 shows that solutions are unstable with respect to “large” perturbations of interaction rates; these hints are illustrated by numerical simulations that point out how much solutions corresponding to different values of parameters stay away from each other as t → +∞

A nonconservative kinetic model under the action of an external force field for modeling the medical treatment of autoimmune response

In this paper, we develop a new nonconservative kinetic framework to be applied for the study of immune system dysregulation. From the modeling viewpoint, the new kinetic model regards a system, composed of stochastically interacting agents, under the action of an eternal force field. According to the application perspectives of this paper, the external force field has a specific analytical shape. In this case, some analytical results are proved, i.e. existence, uniqueness, positivity and boundedness of solution of the related Cauchy problem, under suitable assumptions, at least locally in time. Then, the models is refined to be implemented for the study of treatment strategies in case of autoimmune response. Specifically, we distinguish the autonomous case from the nonautonomous one, representing absence or delivery of drugs, respectively. The former allows to gain some stability results, still in terms of Hopf bifurcations. Whereas, the latter is qualitatively studied. Numerical simulations are provided for both schemes. They show the adherence of this new framework to the realistic scenarios, confirming its impact and potentiality

The mathematical analysis towards the dependence on the initial data for a discrete thermostatted kinetic framework for biological systems composed of interacting entities

This paper is devoted to a mathematical proof of the continuous dependence on the initial data for the discrete thermostatted kinetic framework, for all T > 0. This is a versatile model for describing the time-evolution of a biological complex system which is composed by a large number of interacting entities, called active particles, and is subjected to an external force field due to the environment. A thermostat term is introduced in order to keep the 2nd-order moment of the system, corresponding to the physical global activation energy, constant in time. This model is expressed by a system of nonlinear ordinary differential equations with quadratic nonlinearity

Impact of soil conservation on crop production in the Northern Ethiopian Highlands:

"Land degradation, in the form of soil erosion and nutrient depletion, threatens food security and the sustainability of agricultural production in many developing countries. Governments and development agencies have invested substantial resources in promoting soil conservation practices, in an effort to improve environmental conditions and reduce poverty. However, very limited rigorous empirical work has examined the economics of adopting soil conservation technology. This paper investigates the impact of stone bunds on crop production value per hectare in low and high rainfall areas of the Ethiopian highlands using cross-sectional data from more than 900 households having multiple plots per household. We use modified random effects models, stochastic dominance analysis (SDA) and matching methods to ensure robustness. The parametric regression and SDA estimates are based on matched observations obtained from nearest neighbor matching using propensity score estimates. This is important because conventional regression and SDA estimates are obtained without ensuring the existence of comparable conserved and non-conserved plots within the distribution of covariates. Here, we use matching methods, random effects and Mundlak's approach to control for selection and endogeneity biases that may arise due to correlation of unobserved heterogeneity and observed explanatory variables. The three methods used herein consistently show that plots with stone bunds are more productive than those without such technologies in semi-arid areas but not in higher rainfall areas, apparently because the moisture-conserving benefits of this technology are more beneficial in drier areas. This implies that the performance of stone bunds varies by agro-ecological type, suggesting a need for the design and implementation of appropriate site-specific technologies." from Authors' AbstractSoil conservation, Crop production, Agro-ecology, Matching method, Stochastic dominance, Modified random effects model, Land management,