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843 Research products, page 1 of 85

  • Publications
  • 2017-2021
  • Preprint
  • Hyper Article en Ligne
  • Mémoires en Sciences de l'Information et de la Communication
  • COVID-19

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  • English
    Authors: 
    Hua, Ping;
    Publisher: HAL CCSD
    Country: France

    By using panel data of 15 Chinese manufacturing industries over the 2005-2014 period from OECD TiVA and WIOD databases, the impact of China's GVCs participation on labor productivity is estimated. We find that while the productivity elasticity of the share of sector's foreign value added relative to sector's exports known as sector backward linkages is negative, that relative to China's gross exports named structure backward linkage is positive. As the annual average growth rates of both backward linkages are negative, China's backward linkages have contributed to productivity growth of 6.41% per year on average. We find that the positive productivity elasticity of the share of domestic intermediate goods embodied in exports of third countries relative to sector's exports, named sector forward linages together with a positive annual average growth rate, and that relative to China's exports named structure forward linkages together with a negative annual average growth rate, have increased productivity of 1.97% per year on average. We find finally that GVCs position is improved from 0.3 in 2005 to 0.7 in 2014. China's GVCs participation exerted positive productivity effects via optimizing resource allocation inside sectors towards more efficiency ones, via moving up from low productivity backward linkages to higher productivity forward linkages and via improving its position. This diminished the risk to be entrenched in low-profitability low productivity growth GVCs activities in China. However, the productivity contribution of backward linkages 3 times higher than that of forward linkage suggests that the future positive productivity impact of GVCs moving up may be much more difficult in a less favorable context (trade war between China and USA, reindustrialization and trade protection related to Covid-19 for example).

  • French
    Authors: 
    Mondello, Gérard;
    Publisher: HAL CCSD
    Country: France

    La pandémie de Covid-19 a bouleversé non seulement l'économie de la plupart des pays, mais aussi le domaine scientifique médical. Les opinions publiques se sont immiscées dans les choix des essais thérapeutiques comme le montrent les controverses autour des protocoles utilisant l'hydroxychloroquine. Le choix du public pour ces traitements est expliqué comme l'application d'un "pari de Pascal". Cet article analyse la formation du système de croyance des individus en appliquant la théorie de l'ambiguïté et la théorie de l'entropie d'information. Il montre que les choix du public sont le fruit de stratégies communication choisies par les promoteurs de tel ou tel traitement.

  • English
    Authors: 
    Mondello, Gérard;
    Publisher: HAL CCSD
    Country: France

    The Covid-19 pandemic upset both the economies of most countries, but also the field of medical science. As never, public opinion has interfered in the choice of therapeutic trials as evidenced by the controversies surrounding protocols using hydroxychloroquine. The public's choice for these treatments is explained as the application of a kind of individual "Pascal's wager". This article analyses the formation of the belief system of individuals by applying ambiguity theory's insights and information entropy. It shows that the public's choices are the result of efficient communication strategies chosen by these treatments' promoters.

  • Open Access English
    Authors: 
    Martin Henseler; Helene Maisonnave; Asiya Maskaeva;
    Publisher: HAL CCSD
    Country: France

    The worldwide COVID-19 pandemic has affected the tourism sector by closing borders, reducing both the transportation of tourists and tourist demand. Developing countries, such as Tanzania, where the tourism sector contributes a high share to gross domestic product, are facing considerable economic consequences. Tourism interlinks domestic sectors such as transport, accommodation, beverages and food, and retail trade and thus plays an important role in household income. Our study assessed the macroeconomic impacts of COVID-19 on the tourism sector and the Tanzanian economy as a case study of an impacted developing economy. We used a computable general equilibrium model framework to simulate the economic impacts resulting from the COVID-19 pandemic and quantitatively analysed the economic impacts.

  • Open Access English
    Authors: 
    Arnault Pachot; Adélaïde Albouy-Kissi; Benjamin Albouy-Kissi; Frédéric Chausse;
    Country: France

    International audience; The disruption of supplies during the Covid-19 crisis has led to shortages but has also shown the adaptability of some companies, which have succeeded in adapting their production chains quickly to produce goods experiencing shortages: hydroalcoholic gel, masks, and medical gowns. These productive jumps from product A to product B are feasible because of the know-how proximity between the two classes of products. The proximities were computed from the analysis of co-exports and resulted in the construction of the product space. Based on the product space, as well as the customer-supplier relationships resulting from the input-output matrices, we propose a recommender system for companies. The goal is to promote distributed manufacturing by recommending a list of local suppliers to each company. As there is not always a local supplier for a desired product class, we consider the proximity between products to identify, in the absence of a supplier, a substitute supplier able to adapt its production tools to provide the required product. Our experiments are based on French data, from which we build a graph of synergies illustrating the potential productive links between companies. Finally, we show that our approach offers new perspectives to determine the level of territories' industrial resilience considering potential productive jumps.

  • English
    Authors: 
    Milesi-Gaches, David;
    Publisher: HAL CCSD
    Country: France

    Public transports were strongly impacted by the Covid-19 pandemic through, for example, networks shut down, or lockdown and distancing measures. Transport scenarios are helpful tools on which policies, development and management strategies are built. To see if we can still rely on pre-2020 scenarios in a post-pandemic world, it is important to explore if the epidemic, pandemic or infectious (EPI) risk was addressed or discussed. Hence, this paper proposes a systematic review to explore how the EPI risk and health are discussed in transport scenarios and transport scenario guidance documents. Both scientific and grey literatures were reviewed, through 17 search engines, with French and English keywords. Data were then processed through a Factor Analysis of Mixed Data (FAMD). The sample of 110 documents underlines a poor consideration for the EPI risk, with only 4 papers addressing, 7 mentioning and 37 indirectly mentioning the EPI risk, despite an important consideration for health (101 documents discussed health, with an average number of 3.45 health topics addressed). When discussed, the EPI risk is always addressed through the prism of health although it is recognized as a global disruptor for the whole society. Indeed, the more health topics are addressed, the more it is likely to find the EPI risk addressed in public transport scenarios or guidance documents.; Les transports publics ont été fortement impactés par la pandémie de Covid-19 à travers, par exemple, des fermetures de réseaux, ou des mesures de confinement et de distanciation. Les scénarios de transport sont des outils utiles sur lesquels reposent les politiques, les stratégies de développement et de gestion. Pour voir si nous pouvons toujours nous appuyer sur des scénarios pré-2020 dans un monde post-pandémique, il est important d'explorer si le risque épidémique, pandémique ou infectieux a été abordé ou discuté. Par conséquent, cet article propose une revue systématique pour explorer comment le risque épidémique et la santé sont discutés dans les scénarios de transport et les documents de guidance sur les scénarios de transport. La littérature scientifique et la littérature grise ont été passées en revue, via 17 moteurs de recherche, avec des mots-clés en français et en anglais. Les données ont ensuite été traitées par une analyse factorielle de données mixtes (AFDM). L'échantillon de 110 documents souligne une mauvaise prise en compte du risque épidémique, avec seulement 4 articles l'abordant, 7 le mentionnant et 37 le mentionnant indirectement, malgré une prise en compte importante de la santé (101 documents traitent de la santé, avec un nombre moyen de 3,45 sujets de santé abordés). Lorsqu'il est discuté, le risque épidémique est toujours abordé à travers le prisme de la santé bien qu'il soit reconnu comme un perturbateur global pour l'ensemble de la société. En effet, plus les sujets de santé sont abordés, plus il est probable de retrouver le risque épidémique abordé dans les scénarios de transport public ou les documents de guidance sur l'élaboration de scénarios.

  • Open Access English
    Authors: 
    Marie Alexandre; Romain Marlin; Mélanie Prague; Coleon Severin; Nidhal Kahlaoui; Sylvain Cardinaud; Thibaut Naninck; Benoit Delache; Mathieu Surenaud; Mathilde Galhaut; +12 more
    Publisher: HAL CCSD
    Country: France

    AbstractThe definition of correlates of protection is critical for the development of next generation SARS-CoV-2 vaccine platforms. Here, we propose a new framework for identifying mechanistic correlates of protection based on mathematical modelling of viral dynamics and data mining of immunological markers. The application to three different studies in non-human primates evaluating SARS-CoV-2 vaccines based on CD40-targeting, two-component spike nanoparticle and mRNA 1273 identifies and quantifies two main mechanisms that are a decrease of rate of cell infection and an increase in clearance of infected cells. Inhibition of RBD binding to ACE2 appears to be a robust mechanistic correlate of protection across the three vaccine platforms although not capturing the whole biological vaccine effect. The model shows that RBD/ACE2 binding inhibition represents a strong mechanism of protection which required significant reduction in blocking potency to effectively compromise the control of viral replication.One Sentence SummaryA framework for modelling the immune control of viral dynamics is applied to quantify the effect of several SARS-CoV-2 vaccine platforms and to define mechanistic correlates of protection.

  • English
    Authors: 
    Kırmızı, Meriç;
    Publisher: HAL CCSD
    Country: France

    The author greatly acknowledges the generous support and assistance by FFJ/Michelin Foundation for the work.; This study searches for French urban mobility practices with the dilemma of planned versus lived spaces with a focus on the specific urban planning practice of pedestrianization. The contradictory interplay of residential, commercial and transport-led mobility is studied in Paris through direct observation, primary and secondary data collection. Moreover, the possible impacts of the on-going pandemic on this interplay of personal mobility, residential mobility and commercial mobility is recognized as a major factor –a game changer– in the Paris study. The Paris study findings are compared to Japanese pedestrianization practices from a perspective of municipally-led and gentrification-induced mobility practices as part of the urban neoliberal agenda.The Paris field study was made from February to June 2021. It composed mainly of an online survey with Paris (Île-de-France) residents and a corresponding paper survey with shopkeepers of three local shopping streets in Paris, including Rue Montorgueil-Rue des Petits Carreaux (in 2nd arrondissement), Rue Cler (in 7th arrondissement) and Rue Daguerre (in 14th arrondissement). Both surveys were translated into French and had multiple choice questions regarding the respondent’s personal situation, daily mobility habits and ideas on municipal pedestrianization efforts. The shop survey also had questions on the type of commerce, the effects of COVID-19 on one’s business and ideas on the effects of shopping street pedestrianization on one’s business in terms of number of customers, sales and shop value. The online resident survey was responded to by 119 people. The shop survey was done on Rue Montorgueil (31), Rue des Petits Carreaux (11), Rue Cler (25), Rue Daguerre (45), and the side streets of these shopping streets (9) on paper with the willing shopkeepers, who amounted to 121 altogether. Although the small size of the study surveys is a limitation of this study, the additional oral communication with the English-speaking shopkeepers about mobility and pedestrianization practices in Paris helped to mitigate this limitation. The online resident survey had been kept on purpose at Paris (Île-de-France) level with the intention of getting as much opinion as possible of Parisians on municipal pedestrianization efforts. The survey analysis that had been conducted at two different geographical levels—Paris (Île-de-France) and specific local shopping streets—on purpose indicated that Parisians can take a different stance against the on-going changes in the urban mobility regime of Paris, depending on their outlook as a resident or a local business. In that sense, their attitudes are not carved in stone, but they are quite flexible. Furthermore, the application of nonparametric tests of Chi-square test of independence and Fisher’s exact test indicated statistically significant relationships among the data variables, such as age and ideas on pedestrianization (resident survey); duration of residence in Paris (Île-de-France) and ideas on pedestrianization (resident survey); and place of residence and mode of transport to work (shop survey). Additional critical comments were made by some of the shopkeepers on Rue Cler and Rue Daguerre. Pedestrianization seems to create common problems for shops’ regular product deliveries, when their customers want to make large purchases at once, or if they have luggage (as mentioned by hoteliers) in particular. A couple of shopkeepers also heavily criticized a lack of municipal support for local independent businesses, and urban planners who did not ask about their opinions regarding their street’s pedestrianization as well as a wrong prioritization of pressing urban issues. Despite all these significant critiques, the study also found enormous support for the municipal pedestrianization efforts. This study also looked at the real estate values by taking a snapshot of Paris apartment and shop values on two online sites, including: paris-housing.com and thestorefront.com to search for a possible connection between higher than average real estate prices, used as a proxy for gentrification and pedestrianization. The study acknowledges that private agencies may modulate their database and housing offers in accordance with a specific group of customers, hence their online catalogues may not represent the actual price averages as a whole. Yet other potential databases were out of reach for the researcher because of language and economic barriers. Based on this simple real estate data analysis, although the m2 rental values for apartments and shops that are located near pedestrian streets seem to be higher than the Paris average in a few cases, this is not enough to conclude that there is a statistically significant relationship between pedestrianization and real estate values. It would require a consideration of the mediating factors, such as the assets’ own qualities, centrality, convenience, and availability of facilities and greenery nearby to cancel out their effects besides a more long-term data to compare the pre- and post-pedestrianization rental values. The paper concludes that despite the common tendency to prioritize active transport modes, such as walking and bicycling by the urban mobility regimes belonging to countries at different development levels, the mobility-based urban change policy and practices cause differing outcomes in different contexts. These can range from the more beneficial, such as resilience against environmental and health crises to the more controversial, including involuntary moves of people and shops (displacement) and more expensive, over-aestheticized cities of consumption (touristification and gentrification) with strengthened socio-economic demarcation lines between their citizens. The research underlines the possibility that popular urban policy discourses, in this case, a pedestrian-friendly city might create just the opposite ends depending on their way of implementation and contextual factors. At the same time, this paper argues that only by taking into account the opposite political stances of: the right to stay put, place-making, dwelling, anti-displacement, occupy and slow city movements in relation to the use of city space just as much as fluidity, liquidity, and mobility, more even forms of urban mobility can be achieved in the crisis-tested contemporary cities of the world.

  • English
    Authors: 
    Mendez, Simon; Nicolas, Alexandre;
    Publisher: HAL CCSD
    Country: France

    The COVID-19 pandemic has prompted numerous fluid dynamical simulations of the propagation of potentially virus-laden respiratory droplets. While these studies have highlighted the apparent sensitivity of the numerical results to the sizes of the emitted droplet and the local humidity, many of them are still performed in stagnant air, i.e., without any external air flow. This very short note demonstrates, on the basis of coarse-grained fluid dynamical simulations in a simple generic setting, that even modest winds or air draughts strongly impact the risks of short-ranged transmission via droplets. The induced dispersion of droplets may contribute to explaining the lower risks of viral transmission experienced outdoors, even at short range.

  • Open Access English
    Authors: 
    Esteban A. Hernandez-Vargas; César Parra-Rojas; Sorin Olaru;
    Publisher: HAL CCSD
    Country: France

    AbstractAntimicrobial resistance is a major threat to global health and food security today. Scheduling cycling therapies by targeting phenotypic states associated to specific mutations can help us to eradicate pathogenic variants in chronic infections. In this paper, we introduce a logistic switching model in order to abstract mutation networks of collateral resistance. We found particular conditions for which unstable zero-equilibrium of the logistic maps can be stabilized through a switching signal. That is, persistent populations can be eradicated through tailored switching regimens.Starting from an optimal-control formulation, the switching policies show their potential in the stabilization of the zero-equilibrium for dynamics governed by logistic maps. However, employing such switching strategies, deserve a specific characterization in terms of limit behaviour. Ultimately, we use evolutionary and control algorithms to find either optimal and sub-optimal switching policies. Simulations results show the applicability of Parrondo’s Paradox to design cycling therapies against drug resistance.

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