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Factors controlling atmospheric DMS and its oxidation products (MSA and nssSO<SUB>4</SUB><SUP>2-</SUP>) in the aerosol at Terra Nova Bay, Antarctica
No full textInternational audienceThis paper presents the results of simultaneous high time-resolution measurements of biogenic aerosol (methane sulfonic acid (MSA), non-sea salt sulfate nssSO42-) with its gaseous precursor dimethylsulfide (DMS), performed at the Italian coastal base Mario Zucchelli Station (MZS) in Terra Nova Bay (MZS) during two summer campaigns (2018-2019 and 2019-2020). Data on atmospheric DMS concentration are scarce, especially in Antarctica. The DMS maximum at MZS occurs in December, one month earlier than at other Antarctic stations. The maximum of DMS concentration is connected with the phytoplanktonic senescent phase following the bloom of Phaeocystis antarctica that occurs in the polynya when sea ice opens up. The second plankton bloom occurs in January and, despite the high dimethylsufoniopropionate (DMSP) concentration in seawater, atmospheric DMS remains low, probably due to its fast biological turnover in seawater in this period. The intensity and timing of the DMS evolution during the two years suggest that only the portion of the polynya close to the sampling site produces a discernible effect on the measured DMS. The closeness to the DMS source area and the occurrence of air masses containing DMS and freshly formed oxidation products allow us to study the kinetic of biogenic aerosol formation and the reliable derivation of the branch ratio between MSA and nssSO42- from DMS oxidation that is estimated to be 0.84±0.06. Conversely, for aged air masses with low DMS content, an enrichment of nssSO42- with respect to MSA, is observed. We estimate that the mean contribution of freshly formed biogenic aerosol to PM10 is 17 % with a maximum of 56 %. The high contribution of biogenic aerosol to the total PM10 mass in summer in this area highlights the dominant role of the polynya on biogenic aerosol formation. Finally, due to the regional and year-to-year variability of DMS and related biogenic aerosol formation, we stress the need for long-term measurements of seawater and atmospheric DMS and biogenic aerosol along the Antarctic coast and in the Southern Ocean
Microplastics in sewer sediments of the Parisian combined sewer network
No full textInternational audienceA sewer management system consists of sewer network and wastewater treatment plants (WWTPs). Since microplastics (MPs) were detected in wastewater, their occurrence and fate in WWTPs has been investigated in the last decades, while it was not the case of sewer networks. Sedimentation occurs inside sewer networks when contaminants detach from wastewater and settle down instead of being transported to WWTPs. This happens due to moderate flow rate of sewage during nights and dry periods, leading to the formation of wet deposits, named sewer sediments. Once the flow rate increases rapidly during wet weather, sewer sediments might be resuspended, releasing contaminants into wastewater. In case of heavy rain events, when combined sewer overflows happen, wastewater is discharged into the environment without treatment. MPs, found abundant in wastewater, may act similarly to other contaminants – trapped in sewer sediments and released later during intense events. To examine this hypothesis, samples were collected from sand chambers inside Parisian combined sewer networks to have a first idea about MP content inside sewer sediments. This study willincrease the knowledge on the occurrence and fate of MPs in the whole sewer system. The collected sewer sediments were highly heterogeneous from organic-rich to grainy components. They were freeze-dried to remove water content and sieved through 5mm mesh to discard large items. A subsample of 0.5g then underwent chemical oxidation with H2O2 and density separation with NaI to isolate MPs from the environmental matrix. The full subsamplewas scanned with the automated µ-FTIR mapping (Nicolet iN10 MX, Thermo Scientific). Data processing was done with the siMPle software to identify the polymers composing the particles. MPs were detected in all samples, ranging from 5×103 to 178×103 particle/kg dry weight with polypropylene as the most abundant polymer. Besides, the correlation of MPs with TOC content will be explored
Metallic Nanoparticles Adsorbed at the Pore Surface of Polymers with Various Porous Morphologies: Toward Hybrid Materials Meant for Heterogeneous Supported Catalysis
No full textInternational audienceHybrid materials consisting of metallic nanoparticles (NPs) adsorbed on porous polymericsupports have been the subject of intense research for many years. Such materials indeed gain fromintrinsic properties, e.g., high specific surface area, catalytic properties, porous features, etc., of bothcomponents. Rational design of such materials is fundamental regarding the functionalization of thesupport surface and thus the interactions required for the metallic NPs to be strongly immobilizedat the pore surface. Herein are presented some significant scientific contributions to this rapidlyexpanding research field. This contribution will notably focus on various examples of such hybridsystems prepared from porous polymers, whatever the morphology and size of the pores. Suchporous polymeric supports can display pores with sizes ranging from a few nanometers to hundredsof microns while pore morphologies, such as spherical, tubular, etc., and/or open or closed, canbe obtained. These systems have allowed some catalytic molecular reactions to be successfullyundertaken, such as the reduction of nitroaromatic compounds or dyes, e.g., methylene blue andEosin Y, boronic acid-based C–C homocoupling reactions, but also cascade reactions consisting oftwo catalytic reactions achieved in a row
LES INFLUENCEURS INVITES PAR LES MARQUES DE LUXE SUR INSTAGRAM FONT- ILS VENDRE ?
No full textInternational audienceInstagram est devenu le réseau social privilégié du secteur du luxe. Aussi, les marques de luxe invitent des influenceurs, pour accroître l’engagement de leur communauté envers leurs produits. Cette nouvelle tendance entraine un dilemme pour les « maisons » de luxe dont la communication repose sur la rareté et l’exclusivité, alors que les réseaux sociaux développent l’exposition et l’accessibilité. D’où l’importance de comprendre l’influence de ces nouveaux porte-paroles. Or il n’existe pas de travaux de recherche sur les effets des influenceurs invités sur les comptes des marques. Une étude exploratoire menée sur différents comptes de marques de luxe, permet d’analyser les effets des publications des influenceurs invités. Les résultats soulignent la variété des stratégies d’influence, et apportent des recommandations utiles à d’autres secteurs
Aide climatique internationale et commerce
No full textInternational audienceForeign aid allocation by donor countries to developing economies is known to be motivated by the donor country’s bilateral trade interests. Does this apply also to bilateral climate aid? In this paper, we combine theoretical and empirical analyses to investigate how bilateral trade affects donor countries’ allocations of bilateral climate aid. Our theoretical analysis develops a simple model to support our hypothesis that bilateral trade has a positive impact on climate aid transfers. The model highlights the terms-of-trade and positive income effects of climate aid, and predicts a positive relationship between donor countries’ exports to and imports from recipient countries and their climate aid transfers. The empirical analysis is based on bilateral climate aid data for 2002 to 2017. We employ fixed effects and instrumental variable-2 stage least square estimations (IV-2SLS) with a shift-share instrument to overcome the endogeneity of trade. Our empirical results show that donors’ exports have a significant, robust, positive effect on climate aid transfers.On sait que l'allocation de l'aide étrangère par les pays donateurs aux économies en développement est motivée par les intérêts commerciaux bilatéraux du pays donateur. Cela s'applique-t-il également à l'aide climatique bilatérale ? Dans cet article, nous combinons des analyses théoriques et empiriques pour étudier comment le commerce bilatéral affecte l'allocation de l'aide climatique bilatérale par les pays donateurs. Notre analyse théorique développe un modèle simple pour soutenir notre hypothèse selon laquelle le commerce bilatéral a un impact positif sur les transferts d'aide climatique. Le modèle met en évidence les termes de l'échange et les effets positifs de l'aide climatique sur le revenu, et prédit une relation positive entre les exportations et les importations des pays donateurs vers les pays bénéficiaires et leurs transferts d'aide climatique. L'analyse empirique repose sur les données bilatérales relatives à l'aide climatique de 2002 à 2017. Nous utilisons des estimations par moindres carrés à effets fixes et à variable instrumentale en deux étapes (IV-2SLS) avec un instrument de partage de la charge pour surmonter l'endogénéité du commerce. Nos résultats empiriques montrent que les exportations des donateurs ont un effet significatif, robuste et positif sur les transferts d'aide climatique
Passengers receptivity of a new public transport mode: case of a BRT project in Lebanon
No full textInternational audienceAbstract This study examines how far the level of knowledge on a new public transport mode in Lebanon might affect mode choice. Indeed, passenger mode choice is a major issue associated with the effectiveness of new transport projects, as their level of effectiveness and feasibility will depend on the number of new adopters. This investigation is performed by developing mode choice models based on data collected via a questionnaire-based survey. The models were used to compare preferences among private cars, current public transport modes and a newly proposed Bus Rapid Transit system. The driving factors are divided into two categories: economic and psychological. The results reveal that explicit evaluations of several factors on the proposed transport modes yields mode choices different from direct evaluation. Besides, the structure of the utility function reveals that economic driving factors prevail over the psychological aspects, which is the opposite of what is observed with direct mode assessment. Moreover, people’s expectations of the proposed Bus Rapid Transit were significantly positive in terms of usability in addition to operational and economic reliability. This study shows that people’s level of knowledge of previous transport modes and their perceptual expectations of new travel modes must be taken into consideration in the feasibility studies of any transport implementations in the developing countries where the public transport services are discouraged
Les vétérinaires diplômés de l'école d'Alfort de 1815 à 1828
No full textIn 1813, in a context of a shortage of veterinarians, Napoleon signed the Moscow decree, modifying veterinary education. The Alfort school becomes the only first-class school in the country, training veterinary marshals in three years of study but also offering an additional two-year training to the best student, allowing them to obtain the vet doctor's diploma. After describing the historical context of the beginning of the XIXth century with its many political changes and its reforms of veterinary education, of the condition of the veterinary profession in France, of its fight against the empiricals, and especially of the criteria selection of its students, their life within the school and their rigorous teaching as well as the examinations, this thesis focuses on the students of the Alfort school. With both sociological and historical interest, this thesis describes and analyzes the characteristics of 838 students admitted between 1813 and 1824, and for some, graduated between 1815 and 1828. It is based on the construction of an Excel file, built from the collection of information in departmental records. Analyzes show that the marshal students were between 17 and 20 years old in accordance with the admission requirements, the doctor students between 19 and 23 years old, with a gradual increase over the period. The proportion of military students was higher among doctor students (13.9%) than among marshals (8.3%). These students were rarer than expected by the regulatory texts. In addition, scholarship students represented 27.3% of marshals and 58.3% of doctor students. The duration of studies was respectively 3 and 2 years for 52% of marshal students and doctor students. The rate of veterans was lower than expected, 16% of marshals and 4.4% of doctor students, which could be explained by the possibility of catching up repetitions. In addition, veterans were rarer among student marshals continuing their studies in vet medecine. Finally, the diploma of veterinary marshal was awarded from 1813 whereas the diploma of veterinary doctor from 1815. The overall graduation rate for the diploma of veterinary marshal is 58% and by 48,6% for the diploma of veterinary doctor. The total number of diplomas awarded by the Alfort school decreased with the transition to the single veterinary diploma in 1825, from a total of 46.5 diplomas per year to 26.5.En 1813, dans un contexte de pénurie de vétérinaires, Napoléon signe le décret de Moscou, modifiant l'enseignement vétérinaire. L'école d'Alfort devient l'unique école de première classe du pays, formant des maréchaux vétérinaires en trois années d'études mais regroupant également les meilleurs éléments pour leur proposer une formation de deux ans supplémentaires permettant d'obtenir le diplôme de médecin vétérinaire. Après avoir décrit une vue d'ensemble du contexte historique du début du XIXème siècle avec ses nombreux changements politiques et ses reformes de l'enseignement vétérinaire, de la condition de la profession vétérinaire en France, de son combat face aux empiriques, et surtout des critères de sélection de ses élèves, de leur vie au sein de l'École et de leur enseignement rigoureux ainsi que les examens qui les sanctionnaient, cette thèse s'intéresse aux élèves de l'école d'Alfort. Dans un intérêt à la fois sociologique et historique, cette thèse décrit et analyse les caractéristiques de 838 élèves admis entre 1813 et 1824, et pour certains, diplômés entre 1815 et 1828. Elle s'appuie sur la construction d'un fichier Excel, à partir du recueil d'informations dans les archives départementales du Val-de-Marne. Les analyses montrent que les élèves-maréchaux étaient majoritairement âgés d'entre 17 et 20 ans conformément aux conditions d'admission, les élèves-médecins d'entre 19 et 23 ans, avec une augmentation progressive sur la période pour ces derniers. La proportion d'élèves militaires était plus importante parmi les élèves-médecins (13,9% que parmi les élèves-maréchaux (8,3%. Ces élèves étaient moins nombreux que prévu par les textes. Par ailleurs, les élèves boursiers représentaient 27,3% des élèves-maréchaux et 58,3% des élèves-médecins. La durée des études était respectivement de 3 et 2 ans pour 52% des élèves-maréchaux et des élèves-médecins. Le taux de vétérances était plus faible qu'attendu, 16% des élèves-maréchaux et 4,4% des élèves médecins, pouvant s'expliquer par la possibilité de rattraper son redoublement qu'il existait à cette époque. De plus, les vétérances étaient plus rares chez les élèves-maréchaux poursuivant leurs études en tant que médecin-vétérinaire. Enfin, le diplôme de maréchal-vétérinaire a été attribué dès 1813 et celui de médecin-vétérinaire à partir de 1815. Le taux de diplomation global pour le diplôme de maréchal-vétérinaire est de 58% et celui pour le diplôme de médecin-vétérinaire est de 48,6%. Le nombre total de diplômes attribués par l'école d'Alfort a diminué lors du passage au diplôme unique de vétérinaire en 1825, en passant d'un total de 46,5 diplômes par an à 26,5
URGENCE ET NIHILISME : L'ÉMERGENCE DU PUNK HARDCORE AMÉRICAIN
No full textStarting from the hypothesis that the rise of so-called hardcore punk rock in the United States in the late 1970s and early 1980s was not only part of a youth subculture, but, on a more profound level, linked to a certain context and to the psycho-social situation in which American society found itself at the time, this study questions what is the nature of the link between the strictly musical details of this expression and the situation in which it took place, by way of suggesting two notions: “urgency” and “nihilism”.While hardcore punk has received increasing attention over the past two decades, musicologists have yet to do justice to the music. Considering this gap, this research aims first of all to clarify the music itself of this hardcore punk phenomenon, and further, with a view to deciphering the social dimension of this music, based on a scrupulous analysis of “musical materials,” which has been historically established throughout the evolution of what we call guitar-driven short fast rock songs, dating back to Chuck Berry of the 1950s: 3-3-2 rhythmic figure, double stop, power chord, call-response form, verse-chorus alternation and horizontal form, refrain, palm mute and even the composition of a band.In hardcore punk, “nihilistic creation”, with its “urgency,” is not just about the process that pushes musicians towards a certain act of creation: it is the music itself that embodies this nihilism and its urgency within its own formal structure. The “dialectical collaboration” of the two notions connects thereby music and social situation as a mediating link.Partant de l’hypothèse que l’essor de la musique dite punk hardcore, aux États-Unis à la fin des années 1970 et au début des années 1980, n’était pas seulement le résultat d’une sous- culture de jeunes, mais était, bien plus profondément, liée à un certain contexte et à la situation psycho-sociale où se trouvait toute la société américaine d’alors, nous recherchons quelle est la nature du lien entre les modalités proprement musicales de cette expression et la situation où elle s’exprimait en nous appuyant sur deux notions : « urgence » et « nihilisme ».Si le punk hardcore a fait l’objet d’une attention croissante au cours des vingt dernières années, les musicologues n’ont encore guère rendu justice à cette musique. Prenant acte de cette lacune, notre étude vise d’abord à une mise au point quant à la musique du phénomène punk hardcore, et ceci aussi, en outre, en vue de décrypter la dimension sociale de cette musique elle- même à partir d’une analyse scrupuleuse des « matériaux musicaux » eux-mêmes, au sens d’Adorno, qui s’établit historiquement au long de l’évolution de ce que nous nommons chansons rock courtes et rapides emmenées par la guitare, évolution qui remonte au Chuck Berry des années 1950 : la figure rythmique 3-3-2, les doubles cordes, le power chord, la forme appel-réponse, l’alternance couplet-refrain et la forme horizontale, le palm mute et même la composition du groupe.Dans le punk hardcore, la « création nihiliste », avec son « urgence », ne concerne pas seulement le processus qui pousse les musiciens à l’acte de créer : c’est la musique elle-même qui incarne ce nihilisme et son urgence au sein même de sa propre structure formelle. La « collaboration dialectique » des deux notions relie ainsi, comme un lien médiateur, musique et situation sociale
Responsabiliser les entreprises : de l’engagement de proximité à la RSE
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