Current status of the algae production industry in Europe: an emerging sector of the Blue Bioeconomy

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Quantifying and addressing the prevalence and bias of study designs in the environmental and social sciences

Abstract: Building trust in science and evidence-based decision-making depends heavily on the credibility of studies and their findings. Researchers employ many different study designs that vary in their risk of bias to evaluate the true effect of interventions or impacts. Here, we empirically quantify, on a large scale, the prevalence of different study designs and the magnitude of bias in their estimates. Randomised designs and controlled observational designs with pre-intervention sampling were used by just 23% of intervention studies in biodiversity conservation, and 36% of intervention studies in social science. We demonstrate, through pairwise within-study comparisons across 49 environmental datasets, that these types of designs usually give less biased estimates than simpler observational designs. We propose a model-based approach to combine study estimates that may suffer from different levels of study design bias, discuss the implications for evidence synthesis, and how to facilitate the use of more credible study designs

La gestion du risque dans la construction d’indices obligataires

L’objectif de cette thèse est de proposer des schémas de pondérations alternatives visant à prendre en compte le risque dans la construction d’indices obligataires. Nous partons du constat suivant : les indices obligataires qui existent sur le marché sont pondérés en fonction de la capitalisation des émetteurs. L’implication n’est pas négligeable, dans la mesure où utiliser cette approche implique de sur-pondérer les entités les plus endettées. Sur cette base, nous proposons dans le premier chapitre de pondérer les entreprises au sein de l’indice en fonction de leur solvabilité. Dans le deuxième chapitre, toujours sur l’univers des obligations d’entreprises, nous appliquons le principe du risque en parité. Plus précisément, les secteurs sont pondérés de façon inversement proportionnelle à une mesure du risque de crédit innovante : la Duration Times Spread. Enfin, le dernier chapitre s’intéresse à l’application de cette même technique du risque en parité, mais cette fois-ci à l’univers des obligations souveraines. Nous nous engageons dans la modélisation d’une structure de taux à terme, permettant de mesurer le risque de taux d’intérêt dans un contexte global. Plus généralement, nous démontrons que ces pondérations alternatives, qui intègrent une notion de risque (crédit ou taux) et s’éloignent ainsi du pur aspect “niveau d’endettement”, fournissent une nouvelle grille de lecture pour la compréhension de la dynamique des marchés obligataires ainsi que des améliorations significatives dans le profil rendement-risque.In this thesis, we are keen to explore alternative weighting schemes that account for risk in the fixed-income indexing market. We start with the following observation: bond indexes that exist on the market are generally cap-weighted. The implication is not trivial: when holding such index, an investor is exposed to the most indebted issuers. From that standpoint, in the first chapter we make the proposal to consider an issuer’s creditworthiness as a weighting metric. Then in the second chapter, still working on the corporate bond market, we decide to turn to risk-parity indexing. More precisely, sectors are weighted inversely proportional to an innovative credit risk measure. Finally, the third chapter is devoted to the transposition of such risk-based philosophy to the sovereign bond universe. Particularly, we examine term structure modeling to appraise interest rate risk in a global framework. On a more general note, we show that these alternative indexing schemes - that do not emanate from pure indebtedness, but that are rather based on more sensible definitions of risk (credit or interest rate) provide a new reading grid for understanding bond market’s dynamics as well as appealing improvements in the indexes’ risk-return profile

The Risk Parity Principle Applied to a Corporate Bond Index

In this paper, we apply the principle of risk parity to a corporate bondindex, an asset class so far left behind in this literature. Specically, werely on the Duration Times Spread (DTS) a coherent metric for bondcredit risk. We construct indexes based on sector - issuer - and bond levelusing structured block correlation matrices, weights being inversely pro-portional to DTS. Our results provide evidence that applying an EqualRisk Contribution (ERC) principle using DTS in the index design signif-icantly improves corporate bond index risk-adjusted returns. It appearsthat the higher the granularity is, the higher will be the risk-adjusted per-formance enhancements. More generally, the ERC application we presentseems to be a valuable trade-off between heuristic and more complex risk-modeling based weighting schemes

Population dynamics of the brown alga Himanthalia elongata under harvesting pressure

International audienceThrough experimental harvesting, followed by a 12-month monitoring of demographic attributes, we tested the influence of harvesting on the population dynamics of Himanthalia elongata. We further explore the data to test the hypothesis that the canopy would exert a negative effect on the other developmental stages (intraspecific competition) throughout the recovery cycle of the population. This showed that the H. elongata canopy plays a marked seasonal role not by precluding the presence of other developmental stages but by delaying or preventing their growth and development. The removal of the canopy facilitates the transition from one developmental stage to another, eventually permitting a fast recovery of size structure in the population. This study allows us to integrate population dynamics and intraspecific relationships in our understanding of macroalgal recovery patterns

De Louis-André de Brancas à la duchesse de Villeroy : itinéraire d’une collection musicale entre Avignon et Paris.

International audienceThis study presents and reconstructs the musical collection of Louis-André de Brancas, assembled in Avignon from copies made in Paris, and which was used in the new Académie de musique d'Avignon in the 1720's. Rich in opera copies, it was bought in Paris by the duchess of Villeroy, then confiscated by the Bibliothèque nationale during the Revolution.Cette étude présente et reconstitue la collection musicale de Louis-André de Brancas, rassemblée en Avignon à partir de copies faites à Paris, et qui a servi à la nouvelle Académie de musique d'Avignon dans les années 1720. Riche de nombreuses copies d'opéra, elle est achetée à Paris par la duchesse de Villeroy, puis est confisquée par la Bibliothèque nationale à la Révolution

Effects of commercial harvesting of intertidal macroalgae on ecosystem biodiversity and functioning

In 2009, the European Union has defined an organic label for macroalgae, which implies that the commercial harvest of algae shall not cause a significant impact on ecosystems. The aim of this work was to study the effects of hand harvesting of three algae: Focus serratus, Palmaria palmata, and Porphyra linearis on the associated biodiversity and metabolism of the ecosystem. We used the BACI (Before-After Control-Impact) design to assess the impact of the disturbance (i) on the recovery of the harvested species, (ii) on the specific and functional diversity of the associated algal and animal communities, and (iii) for F. serratus and P. linearis, on the metabolism of the area, using benthic chambers. Our work is based on a mix of fundamental and applied research to identify the effects of commercial harvesting regarding long-term changes, biological and functional interactions, and system responses (including socio-economic interactions). Results of the 12-month monitoring on F. serratus showed that canopy loss seemed to have a negative impact mainly on the diversity of the animal community and the metabolism of the studied area. No significant effects were observed on the algal community. The harvesting impact on the animal community was amplified by the settlement of an ephemeral canopy of Ulva spp., a seasonal opportunistic green alga. Results of the 12-month monitoring of P. palmata after harvesting did not show any significant impact. This alga was epiphytic on the dominant canopy of F. serratus, which was thus maintained, minimizing the impact of the harvest. Finally, results of the 12-month monitoring of P. linearis were difficult to interpret because of an unexpected but continuous sand burial of the study site, one month after the beginning of the study and still covering the population after eight months. Hence, effects of P. linearis harvesting were overshadowed by the natural variability. So far, our results have shown that commercial harvesting has different effects according to the target species, which emphasizes the necessity to continue long-term monitoring. Finally, this study also points out the valuable use of a ``fundamental research'' approach to deal with a practical management issue. (c) 2013 Elsevier Ltd. All rights reserved

Thermo-elastic behaviour of a natural quartzite: Itacolumite

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Multiple effects of a Gracilaria vermiculophylla invasion on estuarine mudflat functioning and diversity

International audienceThe invasive Japanese seaweed Gracilaria vermiculophylla has become established over the past several years in numerous European estuaries, from Portugal to Norway. In the Faou estuary (48.295°N-4.179°W, Brittany, France), it forms a dense population at the mud's surface. The effects of G. vermiculophylla on metabolism, diversity, and the food web were studied. Community gross primary production (GPP) and respiration (CR) during emersion, chlorophyll-a content, macrofaunal and meiofaunal diversity and abundance, and stable isotopes (δ13C and δ15N) of representative macrofaunal species and main food sources were measured at low tide in winter, spring, summer 2014, and winter 2015. Results show significant seasonal variation in GPP and CR. Moreover, GPP was significantly higher in areas where G. vermiculophylla was present than in the control area (bare mud). However, this high GPP appeared to be linked to the increase in biomass in primary producers, with their efficiency (primary productivity, i.e. assimilation number) remaining relatively stable compared with the control area. Significant variation in abundance of meiofauna and macrofauna was also detected and new epifaunal species were collected, mainly in Gracilaria-colonized areas. Isotopic food-web Bayesian mixing models strongly suggested that G. vermiculophylla plays a major role in the diet of some dominant species. Mechanisms interacting with the functioning and diversity of the mudflat are discussed. Finally, the invasive seaweed G. vermiculophylla affected the mudflat ecosystem in three ways: as a new primary producer (increase in metabolism), as a habitat-forming species (changes in diversity and abundance of macrofauna and meiofauna), and as a new abundant food source, likely through the detrital pathway