Perishable Items in Multi-Level Inventory Systems

This master thesis studies a two-echelon distribution system for perishable items with two non identical retailers. Each location is managed following a standard continuous (R, Q) ordering policy. The demand occurs solely at the retailers and follows independent Poisson processes. Customers are backordered when the retailer is out of stock. The items are considered as fixed lifetime perishables. Whenever an item perished, it is discarded from the stock. The model includes fix transportation time and the allocation policy at the central warehouse is a First-Come-First-Serve one. This kind of system is very complicated and therefore hard to study. In this master thesis, we focus on a simulation study of 48 different problems with both a FIFO and a LIFO issuing policy at the retailers. The goal of this study is therefore to optimize the values of R in (R, Q) ordering policies considering that the items are perishables. To do so, we try to optimize the values of the reorder points at every location. We also try to find some general behaviour of the system and we compare the FIFO and the LIFO best found solution. More than 1000 hours of computer-time were used for this study. For every problem, we conducted an optimization process to find better values of the reorder points at every location. For the FIFO case, an average cost reduction of more than 20% was found. It exists a good opportunity in term of cost savings while taking into account the perishable characteristic of the items. Another finding of our study is that the LIFO case has good performance comparing to what expected. On average, the costs increase is only 7% while considering a LIFO issuing policy instead of a FIFO one. Moreover, the values of the reorder points for the FIFO best found solution are still the same than the LIFO best found solution in 70% of the problems studied

How to train your myeloid cells: a way forward for helminth vaccines?

Soil-transmitted helminths affect approximately 1.5 billion people worldwide. However, as no vaccine is currently available for humans, the current strategy for elimination as a public health problem relies on preventive chemotherapy. Despite more than 20 years of intense research effort, the development of human helminth vaccines (HHVs) has not yet come to fruition. Current vaccine development focuses on peptide antigens that trigger strong humoral immunity, with the goal of generating neutralizing antibodies against key parasite molecules. Notably, this approach aims to reduce the pathology of infection, not worm burden, with only partial protection observed in laboratory models. In addition to the typical translational hurdles that vaccines struggle to overcome, HHVs face several challenges (1): helminth infections have been associated with poor vaccine responses in endemic countries, probably due to the strong immunomodulation caused by these parasites, and (2) the target population displays pre-existing type 2 immune responses to helminth products, increasing the likelihood of adverse events such as allergy or anaphylaxis. We argue that such traditional vaccines are unlikely to be successful on their own and that, based on laboratory models, mucosal and cellular-based vaccines could be a way to move forward in the fight against helminth infection. Here, we review the evidence for the role of innate immune cells, specifically the myeloid compartment, in controlling helminth infections. We explore how the parasite may reprogram myeloid cells to avoid killing, notably using excretory/secretory (ES) proteins and extracellular vesicles (EVs). Finally, learning from the field of tuberculosis, we will discuss how anti-helminth innate memory could be harnessed in a mucosal-trained immunity-based vaccine

La cosmogonie des Hani au regard des matériaux de la Chine ancienne

Cet article propose de mettre en regard la cosmogonie d'une ethnie minoritaire du Yunnan, les Hani, avec les sources chinoises anciennes à caractère mythologique ou cosmogonique. Près d'un siècle après la publication des « Légendes mythologiques dans le Chou king » d'Henri Maspero, l'enjeu est de vérifier dans quelle mesure les traditions orales de populations contemporaines du monde sinisé peuvent ou non éclairer la recherche historique en matière de mythologie chinoise. L'intérêt principal de la cosmogonie hani provient du fait que celle-ci ordonne de façon chronologique et générationnelle plusieurs thèmes génésiques figurant dans les Classiques confucéens. Dans le même temps, sa structure narrative présente des affinités avec le récit de nature cosmogonique contenu dans le célèbre Almanach de Chu de la période des Royaumes Combattants.This paper compares the cosmogony of a Tibeto-Burman speaking people of Yunnan – the Hanis, with major mythical themes of the Chinese mythology. A century after Henri Maspero's masterpiece “Légendes mythologiques dans le Chou king”, the issue is to gauge the extent to which oral traditions of China's ethnic minorities can be used as an analytical tool for interpreting Chinese ancient mythology. The main interest of the Hani oral tradition lies in the fact that it combines several cosmogonical schemes appearing in the Confucian Chinese classics in a sequential and generational way. Besides, its narrative structure exhibits some similarities with that of the ancient Chinese cosmogony contained in the famous Chu Silk manuscript of the Warring States period.En este artículo se propone un análisis comparativo entre los materiales mitológicos chinos antiguos y la cosmogonía de los Hani, una etnia de lengua tibetano-birmana del Yunnan. El interés de esta tradición oral se cifra en que ordena de manera cronológica y generacional varios temas genésicos que figuran en los clásicos confusianos. Al mismo tiempo, su estructura narrativa presenta afinidades con el relato de naturaleza cosmogónica contenido en el célebre “almanaque de Chu” del período de los Reinos combatientes

Adjust or invest : what is the best option to green a supply chain?

Greening a supply chain can be achieved by considering several options. However, companies lack of clear guidelines to assess and compare these options. In this paper, we propose to use multiobjective optimization to assess operational adjustment and technology investment options in terms of cost and carbon emissions. Our study is based on a multiobjective formulation of the economic order quantity model called the sustainable order quantity model. The results show that both options may be effective to lower the impacts of logistics operations. We also provide analytical conditions under which an option outperforms the other one for two classical decision rules, i.e. the carbon cap and the carbon tax cases. The results allow deriving some interesting and potentially impacting practical insight

BDP : bibliothèque partenaire,l’exemple du Cantal (La)

Les BDP, comme d’autres types de bibliothèques, sont en grande réflexion si ce n’est en mutation. D’aucuns ont pu parler de « modèle en crise »… Ce travail s’intéresse aux nouvelles missions endossées par ces bibliothèques et montrent en quoi celles-ci ne sont jamais qu’un prolongement de leurs attributions traditionnelles. Partenariale, la BDP l’est en effet par nature, depuis les origines, et ce d’abord par le truchement du réseau qu’elle forme avec l’ensemble de ses bibliothécaires-dépositaires. C’est ce que ce travail vise à rappeler avant de mesurer le rôle et l’impact de l’action culturelle et des actions de coopération appliqués à l’échelle départementale