Warlords, Famine and Food Aid: Who Fights, Who Starves?

We examine the effects of famine relief efforts (food aid) in regions undergoing civil war. In our model, warlords seize a fraction of all aid and use it to feed soldiers. They hire their troops within a population of farmers heterogeneous in skills. We determine the equilibrium distribution of labor in this environment and study how the existence and allocation strategies of a benevolent food aid agency affect this equilibrium. Our model allows us to precisely predict who will fight and who will work in every circumstance.Food aid, civil war, warlords, famine

Humanitarian Relief and Civil Conflict

We examine the effects of famine relief efforts (food aid) in regions undergoing civil war. In our model, warlords seize a fraction of all aid entering the region. How much they loot affects their choice of army size; therefore the manner in which aid is delivered influences warfare. We identify a delivery plan for aid which minimizes total recruitment in equilibrium.Humanitarian aid, food aid, civil war, warlords, famine

Addressing the Food Aid Curse

In this paper, we build a model of agrarian economies in which a kleptocratic government taxes farmers to maximize its life-time utility. The model is a dynamic general equilibrium model in which the subsistence of farmers requires a minimum level of consumption. We analyze the effect that a benevolent food aid agency can have in such an environment. If it expects the food aid agency to intervene, the kleptocratic government will starve its farmers, in a clear case of the Samaritan's dilemma. We show that the likelihood of man-made famines, however, can be greatly reduced if the food aid agency intervenes with probability slightly lower than one. No aid agency devoted to saving lives, however, can commit to such policy. We propose a solution to this food aid curse.Food aid, famines, commitment

Etude de l'interaction entre un manipulateur et son environnement : identification des paramètres et réglage du contrôleur

Exploitation des mines souterraines -- Description de la tâche de chargement -- Modélisation de la force de coupe -- Simplification de certains aspects -- Modélisation d'une interaction -- Objectifs de recherche -- Description d'une interaction -- Modélisation du système étudié -- Identification -- Choix de la technique -- Application au système à l'étude -- Expérimentations sur le système réel -- Contrôle et identification -- Manipulateur

Spherulitic Crystal Growth Drives Mineral Deposition Patterns in Collagen-Based Materials

The formation of the hard tissues that provide support and mobility to organisms is achieved through the interplay of inorganic crystals and an organic framework composed of collagen and a small percentage of non-collagenous proteins. Despite their clinical relevance, the mechanisms governing mineralization of the extracellular matrix are still poorly understood. By using 3D electron tomography and high-resolution electron microscopy imaging and spectroscopy, it has been demonstrated that mineralization proceeds through a spherulitic-like crystal growth process. First, aggregates of disordered crystals form in the interfibrillar spaces, which lead to the mineralization of adjacent fibrils. Mineral propagates steadily through the inter- and intrafibrillar spaces of the collagen structure forming layered spherulites that grow to confluence. The structure of the collagen fibrils serves as a protein scaffold to guide the formation of a myriad of platelet-shaped crystallites that make up each of these spherulites. At their periphery, nanosized unmineralized areas remain, leading to the formation of the characteristic lacy pattern observed in the transversal cross-section of mature calcified tissues. This study provides fundamental insights into the bone formation process and represents a potential strategy for complex materials designProjekt DEA

Hypermineralization of Hearing-Related Bones by a Specific Osteoblast Subtype

Auditory ossicles in the middle ear and bony labyrinth of the inner ear are highly mineralized in adult mammals. Cellular mechanisms underlying formation of dense bone during development are unknown. Here, we found that osteoblast-like cells synthesizing highly mineralized hearing-related bones produce both type I and type II collagens as the bone matrix, while conventional osteoblasts and chondrocytes primarily produce type I and type II collagens, respectively. Furthermore, these osteoblast-like cells were not labeled in a “conventional osteoblast”-specific green fluorescent protein (GFP) mouse line. Type II collagen-producing osteoblast-like cells were not chondrocytes as they express osteocalcin, localize along alizarin-labeled osteoid, and form osteocyte lacunae and canaliculi, as do conventional osteoblasts. Auditory ossicles and the bony labyrinth exhibit not only higher bone matrix mineralization but also a higher degree of apatite orientation than do long bones. Therefore, we conclude that these type II collagen-producing hypermineralizing osteoblasts (termed here auditory osteoblasts) represent a new osteoblast subtype. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).Kuroda Y., Kawaai K., Hatano N., et al. Hypermineralization of Hearing-Related Bones by a Specific Osteoblast Subtype. Journal of Bone and Mineral Research, 36, 8, 1535. https://doi.org/10.1002/jbmr.4320

Mineral content and biomechanical properties of fibrolamellar bone

editorial reviewe

Mineralization and Mechanical Insights of Cement Lines in Human Osteonal Bone

peer reviewe

A Multimodal Analysis of Cement Lines in Human Osteonal Bone

peer reviewe