Resource depletion potentials from bottom-up models:Population dynamics and the Hubbert peak theory

Life cycle impact assessment uses so-called characterization factors to address different types of environmental impact (e.g. climate change, particulate matter, land use…). For the topic of resource depletion, a series of proposals was based on heuristic and formal arguments, but without the use of expert-based models from relevant research areas. A recent study in using fish population models has confirmed the original proposal for characterization factors for biotic resources of the nineties. Here we trace the milestones of the arguments and the designs of resource depletion, delivering an ecological-based foundation for the biotic case, and extend it by a novel analysis of the Hubbert peak theory for the abiotic case. We show that the original abiotic depletion potential, used for two decades in life cycle assessment, estimates accurately a marginal depletion characterization factor obtained from a dynamic model of the available reserve. This is illustrated for 29 metal resources using published data

REIGNY, Dossier documentaire (1369-1371)

La période de la Guerre de Cent ans a été l’occasion pour toutes sortes de brigands de piller ou simplement rançonner villes, villages et monastères isolés. Au milieu du XIVe siècle, les Grandes compagnies ont traversé le royaume de France et les régions avoisinantes en ravageant tout ou presque sur leur passage. Parmi toutes les autres, la région d’Auxerre a connu elle-aussi ce fléau. En effet, dans les années 1360, une bande d’Anglais et de Bretons s’est installée à Arcy-sur-Cure et en a pr..

Les archives des Cisterciennes de Bourgogne (XIIe-XVe siècles)

Au tournant du XIIe siècle, à la naissance des premiers monastères cisterciens, le monachisme féminin a déjà une riche histoire. Dans le contexte du renouveau érémitique et monastique, les femmes, volontairement ou non, se rassemblent en communautés d’orantes, parfois à proximité des nouveaux établissements masculins. Si les moines blancs sont réputés peu ouverts aux aspirations spirituelles féminines, les moniales sont pourtant bien présentes dans l’Ordre au XIIIe siècle, ne serait-ce que pa..

REIGNY, Un noyé dans la Cure…

L’acte 1405 Jacques Pourrotte, bourgeois de Vermenton, garde du sceau de la prévôté de Bétry-en-Vermenton, notifie que Richard Pourrotte s’est rendu à Reigny à la demande de Jean de Birey, procureur des moines de Reigny, pour voir le corps d’un homme pêché dans la Cure. Ses proches, Jean Legris et Thomas Burgaut, attestent qu’il était de Montigny sur la Loire et qu’il n’était pas excommunié. Dans ces conditions, il peut être enterré en terre consacrée. Jean de Birey obtient que les moines soi..

Écrits et écritures dans le monde cistercien. Pratiques et gestion de l’écrit monastique (xiie-xiiie siècles)

Alors que les études sur les abbayes cisterciennes se focalisent volontiers sur les institutions – les fondations monastiques et les branches, le gouvernement de l’ordre et le fonctionnement des chapitres généraux  –, l’art, l’architecture ou l’archéologie, voire sur l’économie – granges, espaces cultivés, élevage, industrie  –, mon projet – en lien avec les CBMA – porte sur les pratiques et la gestion de l’écrit dans les monastères cisterciens, c’est-à-dire non seulement sur leur documentati..

A tool to guide the selection of impact categories for LCA studies by using the representativeness index

Understanding the environmental profile of a product computed from the Life Cycle Assessment (LCA) framework is sometimes challenging due to the high number of environmental indicators involved. The objective here, in guiding interpretation of LCA results, is to highlight the importance of each impact category for each product alternative studied. For a given product, the proposed methodology identifies the impact categories that are worth focusing on, relatively to a whole set of products from the same cumulated database. The approach extends the analysis of Representativeness Indices (RI) developed by Esnouf et al. (2018). It proposes a new operational tool for calculating RIs at the level of impact categories for a Life Cycle Inventory (LCI) result. Impact categories and LCI results are defined as vectors within a standardized vector space and a procedure is proposed to treat issues coming from the correlation of impact category vectors belonging to the same Life Cycle Impact Assessment (LCIA) method. From the cumulated ecoinvent database, LCI results of the Chinese and the German electricity mixes illustrate the method. Relevant impact categories of the EU-standardized ILCD method are then identified. RI results from all products of a cumulated LCI database were therefore analysed to assess the main tendencies of the impact categories of the ILCD method. This operational approach can then significantly contribute to the interpretation of the LCA results by pointing to the specificities of the inventories analysed and for identifying the main representative impact categories

Dinitrogen fixation and dissolved organic nitrogen fueled primary production and particulate export during the VAHINE mesocosm experiment (New Caledonia lagoon)

International audienceIn the oligotrophic ocean characterized by nitrate (NO − 3) depletion in surface waters, dinitrogen (N 2) fixation and dissolved organic nitrogen (DON) can represent significant nitrogen (N) sources for the ecosystem. In this study, we deployed large in situ mesocosms in New Caledonia in order to investigate (1) the contribution of N 2 fixation and DON use to primary production (PP) and particle export and (2) the fate of the freshly produced particulate organic N (PON), i.e., whether it is preferentially accumulated and recycled in the water column or exported out of the system. The mesocosms were fertilized with phosphate (PO 3− 4) in order to prevent phosphorus (P) limitation and promote N 2 fixation. The diazotrophic community was dominated by diatom–diazotroph associations (DDAs) during the first part of the experiment for 10 days (P1) followed by the unicel-lular N 2-fixing cyanobacteria UCYN-C for the last 9 days (P2) of the experiment. N 2 fixation rates averaged 9.8 ± 4.0 and 27.7 ± 8.6 nmol L −1 d −1 during P1 and P2, respectively. NO − 3 concentrations ( 0.05) during P1 (9.0 ± 3.3 %) and P2 (12.6 ± 6.1 %). However, the e ratio that quantifies the efficiency of a system to export particulate organic carbon (POC export) compared to PP (e ratio = POC export / PP) was significantly higher (p 0.05) from the total amount of PON exported (0.10 ± 0.04 µmol L −1), suggesting a rapid and probably direct export of the recently fixed N 2 by the DDAs. During P2, both PON concentrations and PON export increased in the mesocosms by a factor 1.5–2. Unlike in P1, this PON production was not totally explained by the new N provided by N 2 fixation. The use of DON, whose concentrations decreased significantly (p < 0.05) from 5.3 ± 0.5 µmol L −1 to 4.4 ± 0.5 µmol L −1 , appeared to be the missing N source. The DON consumption (∼ 0.9 µmol L −1) during P2 is higher Published by Copernicus Publications on behalf of the European Geosciences Union. 4100 H. Berthelot et al.: Dinitrogen fixation and dissolved organic nitrogen fueled primary production than the total amount of new N brought by N 2 fixation (∼ 0.25 µmol L −1) during the same period. These results suggest that while DDAs mainly rely on N 2 fixation for their N requirements, both N 2 fixation and DON can be significant N sources for primary production and particulate export following UCYN-C blooms in the New Caledonia lagoon and by extension in the N-limited oceans where similar events are likely to occur

Can we assess the model complexity for a bioprocess ? Theory and example of the anaerobic digestion process

In this paper we propose a methodology to determine the structure of the pseudo-stoichiometric coefficient matrix K in a mass balance based model, i.e. the maximal number of biomasses that must be taken into account to reproduce an available data set. It consists in estimating the number of reactions that must be taken into account to represent the main mass transfer within the bioreactor. This provides the dimension of K. The method is applied to data from an anaerobic digestion process and shows that even a model including a single biomass is sufficient. Then we apply the same method to the “synthetic data” issued from the complex ADM1 model, showing that the main model features can be obtained with 2 biomasses

Machine learning models based on molecular descriptors to predict human and environmental toxicological factors in continental freshwater

It is a real challenge for life cycle assessment practitioners to identify all relevant substances contributing to the ecotoxicity. Once this identification has been made, the lack of corresponding ecotoxicity factors can make the results partial and difficult to interpret. So, it is a real and important challenge to provide ecotoxicity factors for a wide range of compounds. Nevertheless, obtaining such factors using experiments is tedious, time-consuming, and made at a high cost. A modeling method that could predict these factors from easy-to-obtain information on each chemical would be of great value. Here, we present such a method, based on machine learning algorithms, that used molecular descriptors to predict two specific endpoints in continental freshwater for ecotoxicological and human impacts. The method shows good performances on a learning database. Then, predictions were derived from the validated model for compounds with missing toxicity/ecotoxicity factors