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This paper analyzes the impact of COVID-19 lockdown measures on children's school resilience. Using an individual fixed-effect linear probability model on Nigeria data, it exploits the quasi-randomness of these measures to estimate their effect on school attendance after the lockdown was lifted. The results show that COVID-19 lockdown measures reduced children's probability of attending school after the school system reopened. This negative impact increased with children's age, reaching a peak among those whose education was no longer compulsory. For schoolchildren in that age group, the negative effect of COVID-19 lockdown measures is likely to be permanent, which, if not reversed, will undermine the quality of the economy-wide future labor force. The paper also finds evidence that in the child marriage-prone North-West part of Nigeria that these measures increased gender inequality in education among children aged 12 to 18. This result suggests that COVID-19 lockdown measures may exacerbate harmful traditional practices such as child marriage.

Climate change and weather shocks pose major challenges for household income security and well-being, especially for smallholder farmers’ communities. In such communities, imperfect risk insurance and labor markets may induce households to use traditional institutions such as polygyny to harness their size and composition to their resilience strategies against these shocks. This paper tests this hypothesis by analyzing how polygyny’s interaction with droughts affects crop yields. For identification, the paper relies on the spatial variation in polygyny’s prevalence across Mali’s rural communes and the randomness of drought episodes. The findings show that polygynous communities are more resilient to drought-induced crop failure. Exploration of the mechanisms shows that polygynous communities diversify their income sources more than monogamous ones, including via child marriage—a phenomenon known to undermine women’s outcomes. As the literature links polygyny to underdevelopment, interventions to eliminate it should make formal resilience and adaptation strategies available to drought-prone communities. Failure to do so may entrench political opposition to enforcing a ban on polygyny and child marriage.

This paper assesses the relationship between the length of recall and nonrandom error in agricultural survey data. Using data from the World Bank's Living Standards Measurement Study–Integrated Surveys on Agriculture in Malawi and Tanzania, the paper shows that key input and output variables are systematically related to the length of the recall period, indicating the presence of nonrandom measurement error. With longer recall periods, farmers report greater quantities of harvest, labor, and fertilizer inputs. Farmers list fewer plots as the recall period increases. The paper argues that it is plausible that farmers overestimate plot-level outcomes, or they forget some of their more marginal plots due to longer recall periods. The analysis also finds evidence of measurement error related to the length of recall in common measures of agricultural productivity. The size of the recall effect typically varies between 2 and 5 percent per additional month of recall length, which is economically significant. With data reliability affecting policy effectiveness, improving agricultural survey data quality remains an important concern. Mainstreaming objective measures where possible and reducing the risk of recall error through shorter recall periods appear to be promising avenues to improve the quality of key variables in agricultural surveys.

Public food procurement (PFP) is a policy instrument that has been used to “link” different objectives at once. We undertake a first systematic review of the scientific literature that deals with PFP in order to 1.) assess the progress of the scientific literature concerning PFP in different areas of the world, 2.) look for differences among them and try to identify the topics on which these studies focuses the most. Accordingly, our research questions deal with the definition of the main conceptual dimensions developed by the academic literature on PFP as well as with the geographical and temporal differences among the dimensions identified. The first evidence is the increase in the number of papers per year during the last decade. Furthermore, the literature on PFP is centred on the concepts of localisation and structured demand and its impacts on food chain actors, on citizen-consumers and on sustainability at large. As a main research result, we provide a conceptual framework of the PFP literature largely based on the concept of linkage that has been first proposed in law and regulation studies., International Journal on Food System Dynamics, Vol 8, No 4 (2017)

Farm capital structure may have contrasting effects on farm efficiency as a strand of the farm efficiency literature as pointed out ( for a review see for example Davidova and Latruffe 2007). Farmers often use external funding both to cover productions costs and to finance investments (machinery, equipment, buildings) to enhance farm economic performance. The debt is necessary to maintain or improve farm productivity and competitiveness by adopting technological innovation needed to increase farm efficiency. At the same time leverage may affects farm efficiency by influencing farm production decision constrained by lower farm expenditure capacity. In this case, farms response may rely on reducing the necessary expenditures to maintain the production assets with negative consequences on farm productivity, growth and efficiency. Finally, farm leverage may affects the farms capacity to react to market shocks adopting the needed strategic adjustments to maintain productivity, efficiency and competitiveness. A relevant case study for assessing this last effect would be the recent surge in price volatility that affected European and world cereal markets starting from 2008. The objective of this paper is to provide new empirical evidence on the relationship between farm capital structure and farm efficiency. In particular we will try to answer the following research question: does higher leverage lead to better performance? The food price volatility that has affected the cereal market from 2008 onwards is a possible stress for cereal farms that must adapt to the rapid drop in prices such as the one observed in 2010. Our research provide a first insight on the evolution of the cereal farms debt-technical efficiency relationship in times of high price volatility., Proceedings in Food System Dynamics, 2016: Proceedings in System Dynamics and Innovation in Food Networks 2016

The use by governments of their purchasing power to achieve social objectives is a practice that dates back to the 19th centuries when regulations were issued in both the USA and England establishing fair wages or maximum working hours per day for firms working under public contracts (McCrudden,2004). Public food procurement (PFP) is another example of how a policy instrument has been used to “link” different objectives at once. We attempted to undertake a first systematic review of the scientific literature that deals with PFP. The first striking evidence is that the number of papers per year shows an almost exponential growth during the last decade providing support to the relevance of this review. Differently from the literature on Public procurement where the themes of contracting and cost minimisation are prevalent, the literature on PFP is centred on the concepts of localisation and structured demand and its impacts on food chain actors as well as citizen-consumers and on sustainability at large. We provide a conceptual scheme of the PFP literature largely based on the concept of linkage that has been first proposed in law and regulation studies and is declined in a rather specific fashion in this field of public procurement.

This work deals with methodological and empirical issues related to multiperiod optimal hedging OLS estimators. We propose an analytical formula for the multiperiod minimum variance hedging ratio starting from the triangular representation of a cointegrated system DGP. Since estimating the hedge ratio matching the frequency of data with the hedging horizon leads to a sample size reduction problem, we carry out a Monte Carlo study to investigate the pattern and hedging efficiency of OLS hedging ratio based on overlapping vs non-overlapping observations exploring a range of hedging horizons and sample sizes. Finally, we applied our approach to real data for a cross hedging related to soft wheat.

A master–slave synchronisation control problem is addressed for current-fed DC and permanent magnet synchronous motors with all uncertain parameters. A measurable exogenous rotor position reference signal, which belongs to the class of biased sinusoidal signals with uncertain bias, amplitude, angular frequency, phase, is to be tracked without assuming its a priori knowledge. An innovative modification of disturbance cancellation techniques allows to prove that an output feedback adaptive nonlinear control scheme, which simply generalises the classical internal-model-based input law, solves the aforementioned problem, with an overall stability proof concerning the entire closed-loop system. The practical effectiveness of the proposed approach is illustrated by experimental results.