Migration, Remittances and Moral Hazard. Evidence from the Kayes Area (Western Mali)

This article uses recent survey data from the Kayes area (Western Mali) to estimate the effect of migration and remittances on the technical efficiency of agricultural households. A theoretical model is developed, which shows that the more insurance is provided by the migrants, the less incentive their families have to work. A production function using panel data with household-specific fixed effects is estimated to test this hypothesis. The probability of being financially supported by migrants is found to significantly contribute to technical inefficiency. This result should help agricultural policy makers formulate more efficient development strategies in the area.technical inefficiency, moral hazard, risk-coping strategy, migration

Strong convergence of a positive preserving drift-implicit Euler scheme for the fixed delay CIR process

In this paper, we consider a fixed delay Cox-Ingersoll-Ross process (CIR process) on the regime where it does not hit zero, the aim is to determine a positive preserving implicit Euler Scheme. On a time grid with constant stepsize our scheme extends the scheme proposed by Alfonsi in 2005 for the classical CIR model. Furthermore, we consider its piecewise linear interpolation, and, under suitable conditions, we establish the order of strong convergence in the uniform norm, thus extending the results of Dereich et al. in 2011.Comment: 24 page

The Formation of Risk Sharing Networks.

This paper examines the formation of risk sharing networks in the rural Philippines. We find that geographic proximity–possibly correlated with kinship–is a major determinant of mutual insurance links among villagers. Age and wealth differences also play an important role. In contrast, income correlation and differences in occupation are not determinants of network links. Reported network links have a strong effect on subsequent gifts and loans. Gifts between network partners are found to respond to shocks and to differences in health status. From this we conclude that intra-village mutual insurance links are largely determined by social and geographical proximity and are only weakly the result of purposeful diversification of income risk. The paper also makes a methodological contribution to the estimation of dyadic models.partage du risque; modèle dyadique; dyadic model; Philippines; Network; risk-sharing; Réseau;

Contingent Loan Repayment in the Philippines.

Using data from the Philippines, this article seeks to understand how households in the study area apparently manage to avoid falling into a debt trap in spite of frequent borrowing. Findings suggest that this is achieved via three institutional features. First, most informal debt carries no interest. Second, for all debts, repayment is postponed in case of a borrower’s difficulty; this is the only insurance feature of debt repayment. Third, while debt principal is seldom forgiven or reduced, interest‐bearing debt does not carry additional interest if debt repayment is delayed. This prevents interest charges from accumulating and debt from snowballing.Dette; Crédit;

Risk and Schooling Decisions in Rural Madagascar: a Panel Data Analysis.

La plupart des ménages ruraux malgaches tirent l’essentiel de leurs revenus de l’agriculture et sont exposés à un fort degré d’incertitude en raison de la fréquence et de l’intensité des aléas frappant les champs de culture ou les troupeaux. En l’absence de marchés du crédit ou de l’assurance, des moyens alternatifs pour éliminer ou atténuer les conséquences défavorables de cette incertitude doivent être trouvés par les ménages. Dans cet article, nous envisageons la possibilité que la mise au travail des enfants constitue un mécanisme de gestion des risques. Afin de tester cette hypothèse, nous examinons les déterminants de la scolarisation en cycle primaire d’un échantillon d’enfants issus de ménages ruraux. Nous examinons notamment le rôle des chocs de revenu subis par les ménages sur les probabilités d’entrée (dans) et de sortie hors de l’école de leurs membres en âge d’être scolarisés, en portant une attention particulière aux questions de genre et d’allocation intra-ménage des ressources. Les résultats indiquent que les chocs transitoires de revenu ont un impact significatif sur la probabilité de sortie de l’école mais pas sur la probabilité d’entrer à l’école. Cela suggère que la déscolarisation des enfants les plus âgés constitue un mécanisme de gestion du risque pour les ménages ruraux.Most households in rural Madagascar are engaged in agriculture and derive a large share of their income from the production of food or cash crops and from animal husbandry. However, agricultural yields can be extremely volatile due to weather conditions, pests, insects, rodents and other calamities. As a result, households record large fluctuations in their incomes that must be dealt with. Since the usual consumption-smoothing market mechanisms are quite limited in the Malagasy context, households need to rely on nonmarket mechanisms or to adopt multi-faceted strategies to cope with risk. In this paper, we examine the possibility that parents obtain informal income insurance by letting their children work. We test this hypothesis by examining the relationship between household income shocks and human capital investment in children. In particular, we investigate whether children’s propensity to join school and to drop out of school responds to transient shocks. We also investigate issues such as gender and intrahousehold resource allocation.Stratégies de gestion des risques; Risk-coping strategies; Décision de scolarisation; Schooling decisions; Transitory shocks; Chocs transitoires;

Transversal magnetotransport in Weyl semimetals: Exact numerical approach

Magnetotransport experiments on Weyl semimetals are essential for investigating the intriguing topological and low-energy properties of Weyl nodes. If the transport direction is perpendicular to the applied magnetic field, experiments have shown a large positive magnetoresistance. In this work, we present a theoretical scattering matrix approach to transversal magnetotransport in a Weyl node. Our numerical method confirms and goes beyond the existing perturbative analytical approach by treating disorder exactly. It is formulated in real space and is applicable to mesoscopic samples as well as in the bulk limit. In particular, we study the case of clean and strongly disordered samples.Comment: 10 pages, 4 figure

Anatomy of Topological Surface States: Exact Solutions from Destructive Interference on Frustrated Lattices

The hallmark of topological phases is their robust boundary signature whose intriguing properties---such as the one-way transport on the chiral edge of a Chern insulator and the sudden disappearance of surface states forming open Fermi arcs on the surfaces of Weyl semimetals---are impossible to realize on the surface alone. Yet, despite the glaring simplicity of non-interacting topological bulk Hamiltonians and their concomitant energy spectrum, the detailed study of the corresponding surface states has essentially been restricted to numerical simulation. In this work, however, we show that exact analytical solutions of both topological and trivial surface states can be obtained for generic tight-binding models on a large class of geometrically frustrated lattices in any dimension without the need for fine-tuning of hopping amplitudes. Our solutions derive from local constraints tantamount to destructive interference between neighboring layer lattices perpendicular to the surface and provide microscopic insights into the structure of the surface states that enable analytical calculation of many desired properties. We illustrate our general findings on a large number of examples in two and three spatial dimensions. Notably, we derive exact chiral Chern insulator edge states on the spin orbit-coupled kagome lattice, and Fermi arcs relevant for various recently synthesized pyrochlore iridate slabs. Remarkably, each of the pyrochlore slabs exhibit Fermi arcs although only the ones with a magnetic one-in-three-out configuration feature bulk Weyl nodes in realistic parameter regimes. Our approach furthermore signal the absence of topological surface states, which we illustrate for a class of models akin to the trivial surface of Hourglass materials KHg$X$.Comment: 24 pages, 17 figure