Long-time evolution of core-collapse supernovae

The puzzle of core-collapse supernovae (CCSN) remains complicated. New insights from theory and observations bring the pieces together, but we still have to witness the complete picture. Simulations of CCSN are key to understand the mechanisms that drive the explosion. While the explosion itself is nowadays studied in great detail, the long-time evolution has received less attention in studies. This is partly because of the high computational costs for comprehensive long-time simulations. However, the seconds after the initial explosion are nevertheless critical for remnant and ejecta properties, as well as for the nucleosynthesis in a CCSN. In this study, we investigate the influence of neutrino heating and rotation on both the explosion and long-time evolution. We perform axisymmetric CCSN simulations and use adjustable parameters that allow us to study a broad range of possible scenarios. Our results suggest that increased neutrino heating is beneficial for the explosion, which is consistent with previous studies. On the other hand, rotation can be detrimental to it. In the long-time evolution, rotation reduces the mass accretion onto the proto-neutron star and creates favorable conditions for the formation of neutrino-driven winds. We furthermore investigate the trajectories of ejected fluid elements by developing a tracer particle scheme. This scheme allows for a comprehensive study of ejecta properties and an estimation of the nucleosynthesis in CCSN simulations. We test the robustness of our main results with simulations of different progenitor stars. Overall, we conclude that the long-time evolution in CCSN is important for the final explosion energy, remnant and ejecta properties

Diffusion of information among small-scale farmers in Senegal: the concept of Farmer Field Schools

Recent research on the Farmer Field School (FFS) approach in agriculture in developing countries has raised some doubts on the economic impacts of this concept and especially the knowledge diffusion effects from trained to non-trained farmers. Based on a study in Senegal this paper hypothesizes that the question of the project placement strategy is vital when analyzing knowledge diffusion effects of FFS in Africa. Results show that the share of trained farmers in a community is a decisive factor for adoption behavior and knowledge diffusion. It is concluded that when introducing an FFS, a critical mass of trained farmers is important to attain effective dissemination of information and to generate positive stimuli for adoption and learning among non-participants.Africa,Senegal,agricultural extension,Farmer Field School,diffusion

Small-scale inland fisheries in Africa: How to collect data for poverty assessment?

Accurate poverty assessments in developing countries require efforts to collect detailed household level data. Especially in Africa, such procedures are time consuming, expensive and can be subject to numerous constraints. In this paper we discuss the procedure of the collection of data on consumption, income and assets from poor households involved in small-scale inland fisheries as well as agricultural activities. A sampling scheme has been developed that captures the heterogeneity in ecological conditions and the seasonality of livelihood options. Sampling includes a three point panel survey of 300 households. The respondents belong to four different ethnic groups randomly chosen from three strata representing different ecological zones. In the first part of the paper the methodological framework, the survey design and interview procedure adapted to the conditions in Northern Cameroon is discussed. The second part of the paper presents selected results of the baseline study on consumption, income and assets for different types of households. In addition the record of past ecological, economic and social shocks is presented. --

Lower partial moments as a measure of vulnerability to poverty in Cameroon

In this paper the class of Lower Partial Moments (LPMs) is used for measuring vulnerability as downside risk of household income in rural Cameroon. This class of established and coherent risk measures has been shown to meet a number of desirable properties. Among others, the LPMs fulfill the focus axiom, and for order greater than zero they are in harmony with expected utility theory under the weak assumption of risk aversion. Through combining the vulnerability measure with a portfolio approach it is possible to distinguish different livelihood systems for which the poverty and vulnerability measures are the explicit result of stochastic distributions of single activities in the households' portfolio and their covariance structure. In particular we consider the four major income generating activities in the study area: Sorghum, millet and rice production, and fishing. The results suggest that in the study area fishermen are less affected by adverse effects on income than other livelihood systems, while rice growers are the poorest and most vulnerable. It is also shown that rice and millet growers are suffering from chronic poverty, while transient poverty is more prevalent among the group of sorghum growers and fishermen. This implication is further confirmed by assuming a moving target equal to the mean portfolio income for the calculation of LPMs. The results of the scenario analysis suggest that policy interventions aiming at a reduction of the covariation structure between income flows from different activities are quite promising

Climate risk and farming systems in rural Cameroon

Climate risk is particularly burdensome to small-scale farmers in developing countries due to heavy dependence on natural resources, limited and erratic rainfall with high inter- and intra-annual variability, and other natural calamities. Numerous studies on climate change suggest that climate variability is expected to increase in the next few decades, and that it is likely to be severe for tropical areas. For the design of better intervention strategies that are capable to stabilize the incomes of the poor and decrease vulnerability, it is mandatory to have a good understanding of the livelihoods of rural populations, and the risks they are facing. This paper presents an approach to measuring climate risk and its impact on livelihood outcomes in fishery-dependent communities in the ya'eres floodplain (Far North Province of Cameroon) by applying portfolio theory and stochastic dominance rules. The focus of the analysis is put on the question, how portfolio decisions of households affect income and risk in different production systems. Assuming possible future scenarios we can derive approximate predictions of the effects of climate change and rural development interventions on income and the 'riskiness' of different activity portfolios. The results suggest that the diversification effect in the study area is limited due to high correlation of income flows from different activities. However, we show that development intervention strategies, which particularly aim at changing the covariation structure of income flows, are most successful in reducing risk, and potentially increasing income

Assessing vulnerability to poverty in fishery dependent communities in Cameroon

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Small-scale inland fisheries in Africa: How to collect data for poverty assessment?

Accurate poverty assessments in developing countries require efforts to collect detailed household level data. Especially in Africa, such procedures are time consuming, expensive and can be subject to numerous constraints. In this paper we discuss the procedure of the collection of data on consumption, income and assets from poor households involved in small-scale inland fisheries as well as agricultural activities. A sampling scheme has been developed that captures the heterogeneity in ecological conditions and the seasonality of livelihood options. Sampling includes a three point panel survey of 300 households. The respondents belong to four different ethnic groups randomly chosen from three strata representing different ecological zones. In the first part of the paper the methodological framework, the survey design and interview procedure adapted to the conditions in Northern Cameroon is discussed. The second part of the paper presents selected results of the baseline study on consumption, income and assets for different types of households. In addition the record of past ecological, economic and social shocks is presented

Diffusion of information among small-scale farmers in Senegal: the concept of Farmer Field Schools

Recent research on the Farmer Field School (FFS) approach in agriculture in developing countries has raised some doubts on the economic impacts of this concept and especially the knowledge diffusion effects from trained to non-trained farmers. Based on a study in Senegal this paper hypothesizes that the question of the project placement strategy is vital when analyzing knowledge diffusion effects of FFS in Africa. Results show that the share of trained farmers in a community is a decisive factor for adoption behavior and knowledge diffusion. It is concluded that when introducing an FFS, a critical mass of trained farmers is important to attain effective dissemination of information and to generate positive stimuli for adoption and learning among non-participants

Farming and rural development in Ukraine: making dualisation work

Rural economy 1. Following the decollectivisation of agriculture in Ukraine, the dualisation between very large commercial farms and small individual farms has become a prevalent trend in the rural areas of Ukraine. 2. Rural farm households would need larger plots. They could benefit from mechanization. 3. Yet, as their crop yields are low and lie close to those of large farms that use far more chemical inputs and machinery, the area expansion could be kept modest. 4. Distribution of land ownership rights and cadastral registration need to be supplemented by introduction and registration of other formal titles such as the right of passage and the user rights in commons. 5. Shareholders of a large farm do not need to know the precise location of their property within the farm. Explicit cadastral registration of parcels into units smaller than the individual field is wasteful. 6. Land users should be made to pay due rent to landowners, private (e.g. pensioners), and public (e.g. municipalities), and no longer predominantly in kind. This could improve social safety nets, stimulate activities in rural villages, and improve the fiscal revenue of local governments. 7. Corporate farms should pay corporate taxes. 8. Since growth in employment has been stagnating in urban areas, rural areas have to provide for it, partly in horticulture, animal husbandry and agricultural processing, and partly in expanded household farms, possibly as small multi-household enterprises or cooperatives, on land returned from commercial farms. Foreign trade 9. Access to exports should be made available to all who deliver goods of adequate quality, and not only to specific trading companies who can get access to export licenses. 10. Product labeling on exports, could with adequate inspections, with labels requiring satisfaction of social as well as environmental standards, provide effective means to complement and support local governance. 11. Ukraine has considerable scope to step up its exports of grain and oilseeds, which might significantly contribute to world food security. Yet, to effectuate this expansion without amplifying prevailing price volatility, Ukraine will have to enhance its management of irrigation, storage and plant protection, to limit its support to biofuels and to abstain from imposition of export bans in response to shortfalls. Nutrient management 12. Large exports amount to large outflow of plant nutrients, and turn recycling and imports of nutrients into a necessity in preventing soil fertility loss and land degradation. Expansion of livestock activities with proper manure management also helps to compensate for this loss. Statistics and governance 13. There is domestic and foreign demand for independent and reliable information on prevailing social and environmental conditions, and trade regimes in Ukraine. A data platform that makes use of the available surveys, and avails of some capacity to conduct new ones could help meeting this need.JRC.J.4-Agriculture and Life Sciences in the Econom