Portail HAL de l'Université du Littoral Côte d'Opale
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Effectual behaviour and frugal innovations: learning from women cocoa farmers in South West Cameroon
No full textSource Agritrop Cirad (https://agritrop.cirad.fr/608914/)International audienceWomen's entrepreneurship is on the rise in Africa although the obstacles they face in setting up new businesses and in running these businesses are significantly higher than those faced by men. Women usually decide to become entrepreneurs out of an economic necessity, and at the same time, out of a lack of other options. But academic literature on women entrepreneurs also states that some specific qualities of women are very crucial for their success as entrepreneurs despite their significantly harsher circumstances. In order to understand women entrepreneurship strategies, this article presents the study of women entrepreneurs in a male-dominated cash crop industry, in cocoa production in Cameroon. The results demonstrate that women, despite all the additional obstacles they face, adopt effectual behaviour to develop solutions adapted to their respective situations, through frugal innovations. Our results demonstrate that women's innovative capacities reduce the risks of the negative effects of shocks and disasters on their households. The highlights of the study are as follows: 1) women are significantly disadvantaged regarding their access to resources; 2) innovations by women entrepreneurs are driven by effectual behaviour; 3) effectual behaviour drives the development of various frugal innovations
Fuel Poverty Exposure and Drivers: A Comparison of Vulnerability Landscape Between Egypt and Jordan
No full textInternational audienceThis article, using ERF-LIS harmonized microdata, develops an empirical model to investigate the unexplored extent and fuel poverty explanatory factors in Egypt and Jordan. First, we use the "Low income-High Consumption" indicator to measure the fuel poverty extent. Second, we implement a multivariate statistical approach to untangle the fuel poor household profile. Then, to explore the factors driving the risk of falling into fuel poverty situations we use a logistic regression model. This research is an important empirical contribution to the sparse literature of fuel vulnerability in MENA countries. It puts forward an empirical approach, which is helpful in discerning and targeting families most in need of energy and financial related assistance. From policy perspectives, the findings provide promising ways of accounting for the fuel poverty phenomenon as a vector of inequality trends in the MENA region. The main findings of the research point to the crucial instrumental role of economic conditions, reducing inequalities and access to education facilities in attenuating fuel poverty in Egypt and Jordan. Policies that mitigate fuel poverty may thus have direct impacts on both well-being and inequalities reduction. Note: This paper is also published as an ERF Working Paper and was presented at the ERF-LIS conference on "Inequality Trends Around the Mediterranean.
Renard y es-tu ?: Une variation autour du problème du renard et des terriers
No full textNous nous intéressons à l'énigme relativement connue "Fox and Holes". Nous envisageons certaines généralisations de cette énigme, que nous résolvons. Nous avons tenu à ce que cet article puisse être apprécié et compris par un public ayant reçu un enseignement secondaire
The Fortuin-Kasteleyn polynomial as a bialgebra morphism and applications to the Tutte polynomial
No full textWe compute an explicit formula for the antipode of the double bialgebra of graphs in terms of totally acyclic partial orientations, using some general results on double bialgebras. In analogy to what was already proven in Hopf-algebraic terms for the chromatic polynomial of a graph, we show that the Fortuin-Kasteleyn polynomial (a variant of the Tutte polynomial) is a morphism of the double algebra of graphs into that of polynomials, which generalizes the chromatic polynomial. When specialized at particular values, we give combinatorial interpretations of the Tutte polynomial of a graph, via covering graphs and covering forests, and of the Fortuin-Kasteleyn polynomial, via pairs of vertex--edge colorings. Finally we show that the map associating to a graph all its orientations is a Hopf morphism from the double bialgebra of graphs into that one of oriented graphs, allowing to give interpretations of the Fortuin-Kasteleyn polynomial when computed at negative values
A High Spatiotemporal Resolution Snow Depth Inversion Solution With Multi-GNSS-IR in Complex Terrain
No full textInternational audienc
L’absentéisme à fondement politique ou religieux
No full textInternational audienceThe starting point for the following discussion is that religious freedom and political freedom, as well as the right to manifest them, benefit from legal protection of constitutional value. However, on the contrary, the rights and obligations that punctuate an employment relationship (whether civil servant or employee) fall under a much weaker legal framework (legal, regulatory, conventional, contractual).Le point de départ des développements qui suivent est que la liberté religieuse et la liberté politique, de même que le droit de les manifester, bénéficient d’une protection juridique de valeur constitutionnelle. Or, au contraire, les droits et obligations qui rythment une relation de travail (de fonctionnaire ou de salarié) relèvent d’un niveau juridique nettement plus faible (légal, réglementaire, conventionnel, contractuel)
Commutative B_infty -algebras are shuffle algebras
No full textWe here construct an explicit isomorphism between any commutative Hopf algebra which underlying coalgebra is the tensor coalgebra of a space and the shuffle algebra based on the same space. This isomorphism uses the commutative structure that governs the product and the eulerian idempotent, as well as the canonical projection on the space . This generalizes Homan's isomorphism between commutative quasi-shuffle and shuffle algebras, which correspond to the case when the structure is given by an associative and commutative product. We develop several examples in details, including the Hopf algebra of finite topologies
Cultural techniques capture diverse phosphate-solubilizing bacteria in rock phosphate-enriched habitats
No full textInternational audiencePhosphorus (P) deficiency is a common problem in croplands where phosphatebased fertilizers are regularly used to maintain bioavailable P for plants. However, due to their limited mobility in the soil, there has been an increased interest in microorganisms that can convert insoluble P into a bioavailable form, and their use to develop phosphate-solubilizing bioinoculants as an alternative to the conventional use of P fertilizers. In this study, we proposed two independent experiments and explored two entirely different habitats to trap phosphatesolubilizing bacteria (PSBs). In the first experiment, PSBs were isolated from the rhizoplane of native plant species grown in a rock-phosphate (RP) mining area. A subset of 24 bacterial isolates from 210 rhizoplane morphotypes was selected for the inorganic phosphate solubilizing activities using tricalcium phosphate (TCP) as the sole P source. In the second experiment, we proposed an innovative experimental setup to select mycohyphospheric bacteria associated to arbuscular mycorrhizal fungal hyphae, indigenous of soils where agronomic plant have been grown and trapped in membrane bag filled with RP. A subset of 25 bacterial isolates from 44 mycohyphospheric morphotypes was tested for P solubilizing activities. These two bacterial subsets were then screened for additional plant growth-promoting (PGP) traits, and 16S rDNA sequencing was performed for their identification. Overall, the two isolation experiments resulted in diverse phylogenetic affiliations of the PSB collection, showing only 4 genera (24%) and 5 species (17%) shared between the two communities, thus underlining the value of the two protocols, including the innovative mycohyphospheric isolate selection method, for selecting a greater biodiversity of cultivable PSB. All the rhizoplane and mycohyphospheric PSB were positive for ammonia production. Indol-3-acetic acid (IAA) production was observed for 13 and 20 isolates, respectively among rhizoplane and mycohyphospheric PSB, ranging, respectively, from 32.52 to 330.27 μg mL-1 and from 41.4 to 963.9 μg mL-1. Only five rhizoplane and 12 mycohyphospheric isolates were positively screened for N 2 fixation. Four rhizoplane PSB were identified as siderophore producers, while none of the mycohyphospheric isolates were. The phenotype of one PSB rhizoplane isolate, assigned to Pseudomonas, showed four additive PGP activities. Some bacterial strains belonging to the dominant genera Bacillus and Pseudomonas could be considered potential candidates for further formulation of biofertilizer in order to develop bioinoculant consortia that promote plant P nutrition and growth in RP-enriched soils
Modèle de sous-couche avec perte de couplage pour la sécurité publque basé sur la communication terminal à terminal.
No full textInternational audienceIn several emergency situations, during natural or human-caused disasters, frontline responders need to be able to communicate and collaborate to properly carry out relief missions. Some countries build their national Public Safety Mobile Broadband based on cellular LTE technology to provide fast, safe, and secure emergency services. However, in several emergency situations, cellular antennas can be overloaded or partially damaged in a manner that affects group communication services. In the last few years, direct device-to-device (D2D) communications have been proposed by the 3GPP as an underlay of long-term evolution (LTE) networks based on proximity, reuse, and hop gains. This paper focuses on a loosely coupled model based on direct D2D communication in a public safety context. Many scenarios related to user membership and network management are detailed. Both the “less cost” and “optimized tree” approaches are proposed and implemented, and their performance is evaluated in terms of the network update number and the resulting average Channel Quality Indicator (CQI). Other optimization approaches, with different CQI thresholds and optimization interval parameters, are simulated to compare their performance with the “optimized tree” approach. By conducting simulations that combine a CQI threshold = 1 and optimization interval = 2 s, it becomes possible to keep an average CQI level close to the “optimized tree” approach, while the costs related to network updates significantly decrease by almost 35%. Other simulations are also carried out to measure the bandwidth required by the control messages between the server and active users. It was found that both inbound and outbound traffic on the server side can be well supported with LTE and 5G networks
Melt infiltration for the preparation of finely dispersed Ni-FeOx nanoparticles on SBA-15 for the hydrodeoxygenation of m-cresol
No full textInternational audienceThe polymer-assisted melting infiltration method was used to finely disperse Ni, Fe and bimetallic Ni-Fe precursors in ordered mesoporous SBA-15 support. This approach allowed to obtain small Ni nanoparticles, in the order of 2 nm in size, with finely dispersed iron oxide surrounding metallic Ni, without evidence of Ni-Fe alloy formation. The catalysts were used in the HDO reaction of m-cresol at 300 °C and atmospheric pressure. The conversion of m-cresol was found to be dependent on Ni content, with the total reaction rate decreasing when Ni is partially replaced by iron. Toluene was the main product obtained for both, mono Ni and bimetallic Ni-Fe catalysts, thus suggesting that nickel nanoparticles when in the form of small sized particles, are the active sites for deoxygenation, independent on the presence of oxophilic iron site in their proximity. Such findings will serve for the further design of effective catalysts for the upgrading of lignin-derived bio-oil