We study the problem faced by a central planner trying to increase the consumption of a good, such as new malaria drugs in Africa. The central planner allocates subsidies to its producers, subject to a budget constraint and endogenous market response. The policy most commonly implemented in practical applications of this problem is uniform, in the sense that it allocates the same per-unit subsidy to every firm, primarily because of its simplicity and perceived fairness. Surprisingly, we identify sufficient conditions of the firms’ marginal costs such that uniform subsidies are optimal, even if the firms’ efficiency levels are arbitrarily different. Moreover, this insight is usually preserved even if the central planner is uncertain about the specific market conditions. Further in many cases, uniform subsidies simultaneously attain the best social welfare solution. Additionally, simulation results in relevant settings where uniform subsidies are not optimal suggest that they induce a nearly optimal market consumption. On the other hand, if the firms face a fixed cost of entry to the market, then the performance of uniform subsidies can be significantly worse, suggesting the need for an alternative policy in this setup. This paper was accepted by Yossi Aviv, operations management.

Artículo de publicación ISIShip routing problems are a particular kind of routing problems where the vehicles to be routed are vessels or ships, usually in maritime environments. In contrast to land routing, ship routing has unique features, including overnight trips, disjoint time windows, not necessarily prespecified routes, and a great uncertainty derived from weather conditions. In this work we present a special ship routing problem, which incorporates many features present in general ship routing settings. We discuss aspects related with data gathering and updating, which are particularly difficult in the context of ship routing. Additionally, we present a GRASP algorithm to solve this problem.We apply our solution approach to a salmon feed supplier based in southern Chile, and present computational results on real data

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We study a subsidies and taxes allocation problem with endogenous market response subject to a budget constraint. The central planner's objective is to maximize the consumption of a good, and she allocates per-unit co-payments and taxes to its producers. We show that the optimal policy taxes the more efficient firms and allocates larger co-payments to less efficient firms, making it impractical. Therefore, we consider the simple and frequently implemented policy that allocates the same co-payment to each firm, known as uniform co-payments, and provide the first worst-case performance guarantees for it. Namely, we show that uniform co-payments are guaranteed to induce a significant fraction of the consumption induced by the optimal policy in small markets, for price-taking (resp. Cournot) producers with affine increasing marginal costs facing any non-increasing (resp. linear) inverse demand function, even for different firms' efficiency levels. Moreover, when compared to the best policy that allocates co-payments only, uniform co-payments induce at least half of the optimal consumption. Furthermore, for Cournot competition with linear demand and constant marginal costs, the latter guarantee increases to more than 85% of the optimal consumption.Our results suggest that uniform co-payments are surprisingly powerful in increasing the market consumption of a good.

Problem definition: Novel life-improving products, such as solar lanterns and energy-efficient cookstoves address essential needs of consumers in the base of the pyramid (BOP). However, their profitable distribution is often difficult because BOP customers are risk-averse, their ability to pay (ATP) is lower than their willingness to pay, and they face uncertainty regarding these products’ value. Academic/practical relevance: We examine two practical strategies from distributors in the BOP: (1) improving the product’s affordability through a discount and (2) increasing awareness of the product’s value. Our results identify BOP-specific operational trade-offs in implementing these strategies. We also propose strategies to manage these trade-offs that can increase consumer surplus in the BOP. Methodology: We introduce a supply chain model for the BOP and analyze the distributor’s pricing problem with refunds as well as the distributor’s optimal budget allocation between strategies (1) and (2). Results: We find that, in the BOP, the distributor’s profit-maximizing budget allocation often yields the lowest consumer surplus. This misalignment between profits and consumer surplus disappears if customers’ ATP is high. Moreover, the misalignment can be resolved if the distributor offers free product returns and commits to a maximum retail price. We confirm the robustness of our results through numerical simulations. Managerial implications: Best operations strategy practices in the BOP can differ significantly from developed markets. Furthermore, BOP customers’ limited ATP and high risk aversion generate a BOP-specific misalignment between profits and consumer surplus. Operational commitments, such as free returns, reduce this misalignment and can serve as a signal to investors of a social enterprise’s focus on consumer surplus.

Purpose To evaluate the incremental effect of perfusion imaging on biopsy target identification at endorectal multi-parametric prostate MRI. Method and materials We retrospectively 52 patients who underwent endorectal multi-parametric prostate MRI for suspected or untreated prostate cancer. Two readers independently identified biopsy targets without and with perfusion images. Results Reader 1 identified 36 targets without and 39 targets with perfusion imaging (p > 0.05). The corresponding numbers for reader 2 were 38 and 38, respectively (p = 0.5). Conclusion Perfusion imaging does not significantly increase the number of biopsy targets identified at endorectal multi-parametric prostate MRI.

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La escuela alberga en su seno un conjunto de factores, de relaciones humanas específicas y concretas que comportan una determinada cultura, si por cultura entendemos el entramado de relaciones humanas que llegan a determinar unas estructuras, que pueden facilitar o dificultar no sólo las propias relaciones, sino incluso la posibilidad de enseñar y de aprender. Tomando como punto de partida la descripción y revisión de la experiencia didáctica con el proyecto Filosofía para Niños y Niñas, así como las investigaciones que sobre este proyecto se han desarrollado desde los años 70 del siglo XX, nos propusimos indagar más profundamente en los aspectos contextuales que pudieran verse afectados por la aplicación de dicho proyecto. A partir de estas consideraciones, nos propusimos el estudio de la incidencia de este proyecto educativo "Filosofía para Niños y Niñas", ideado por el profesor Matthew Lipman en 1969, sobre el clima social del aula. Para ello, diseñamos un estudio cuasiexperimental en el que se recoge una valoración del clima social del aula (utilizando la escala CES de Moos y Trickett) y del nivel de cohesión de la misma (a partir de un análisis sociométrico de cada grupo de alumnos y alumnas) comparando grupos con y sin experiencia en el desarrollo del proyecto Filosofía para Niños y Niñas de 4º de E.S.O. (Educación Secundaria Obligatoria). Los resultados obtenidos nos permiten concluir que la aplicación del Proyecto Filosofía para Niños y Niñas tiene un efecto positivo tanto sobre el clima social del aula como sobre la mejora del nivel de cohesión del grupo /aula. Palabras clave: Clima social de aula, aprendizaje cooperativo, proyecto "Filosofía para Niños y Niñas".