Multi-objective optimization of environmentally conscious chemical supply chains under demand uncertainty

In this work, we analyze the effect of demand uncertainty on the multi-objective optimization of chemical supply chains (SC) considering simultaneously their economic and environmental performance. To this end, we present a stochastic multi-scenario mixed-integer linear program (MILP) with the unique feature of incorporating explicitly the demand uncertainty using scenarios with given probability of occurrence. The environmental performance is quantified following life cycle assessment (LCA) principles, which are represented in the model formulation through standard algebraic equations. The capabilities of our approach are illustrated through a case study. We show that the stochastic solution improves the economic performance of the SC in comparison with the deterministic one at any level of the environmental impact.

La Legenda aurea com a font del teatre hagiogràfic català de tècnica medieval: un tast comparatiu

En aquest treball ens proposem estudiar la influència de la Legenda aurea de Jacobus de Voragine en el teatre hagiogràfic català de tècnica medieval, en concret en tres de les consuetes del ms. 1139 de la BNC: la de sant Jordi, dedicada a l’episodi de la donzella i el drac; la de la conversió de sant Cristòfol i la de sant Mateu. Comptem amb algunes aproximacions anteriors, com és el cas de les consideracions que féu Josep Romeu en la seua edició de les peces hagiogràfiques d’aquest manuscrit (1957). En aquest sentit, aprofitem les seues indicacions com a punt de partida per a oferir una anàlisi més detallada de la manera en què els drames hagiogràfics adapten algunes de les vides contingudes en l’obra de Voragine. Per no allargar-nos excessivament, ens centrem en aquestes tres consuetes, ja que poden ser prou representatives dels diferents tipus d’adaptació teatral de la Legenda aurea.

Discovery of a New Retrograde Trans-Neptunian Object: Hint of a Common Orbital Plane for Low Semimajor Axis, High-inclination TNOs and Centaurs

Although the majority of Centaurs are thought to have originated in the scattered disk, with the high-inclination members coming from the Oort cloud, the origin of the high-inclination component of trans-Neptunian objects (TNOs) remains uncertain. We report the discovery of a retrograde TNO, which we nickname “Niku,” detected by the Pan-STARRS 1 Outer Solar System Survey. Our numerical integrations show that the orbital dynamics of Niku are very similar to that of 2008 KV42 (Drac), with a half-life of ˜500 Myr. Comparing similar high-inclination TNOs and Centaurs (q > 10 au, a <100 au, and i > 60°), we find that these objects exhibit a surprising clustering of ascending node, and occupy a common orbital plane. This orbital configuration has high statistical significance: 3.8-σ. An unknown mechanism is required to explain the observed clustering. This discovery may provide a pathway to investigating a possible reservoir of high-inclination objects.