International Journal of Agricultural Research, Innovation and Technology (IJARIT)
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Global dynamics of a spore producing pathogens epidemic system with nonlocal diffusion process
No full textInternational audienceIn this paper, we analyze a nonlocal spatial epidemic model presenting the diffusion process of a spore producing plant pathogens responsible of one of the most destructive cocoa pods disease. The global existence, compactness and dissipativity of the semiflow generated by the system are established. By defining a threshold number (the basic reproduction number), we first express conditions for the existence of non-trivial stationary states. Next, we show that the qualitative dynamics of the model range from the extinction (i.e. the global stability of the disease-free stationary state), to the persistence (i.e. the global stability of the endemic stationary state) of the epidemics. Finally, we go through some simulations of our general analysis
Control dynamics in rogue trading: Sovereignty and exception-to-the-rule attitudes in the contemporary financial sphere
No full textInternational audienceSovereignty, for Derrida (2005, 2009), is defined by an exception-to-the rule attitude: the sovereign is the one who decides on an exception. A sovereign can thus “go rogue” and behave as an outlaw, transgressing the rules of his own community. This article applies this conception of sovereignty to analysis of the Kerviel-Société Générale (SocGen) rogue trading affair. It examines the exception-to-the-rule attitude found in the actors of the financial sphere (the trader, the bank, the State) and the underlying control dynamics. Our results show that the trader acts as a rogue when he takes the exceptional right to place himself above his bank’s rules on position-taking. The bank is equally rogue when it reserves the exceptional right to place itself above the prudential regulations governing its sector. The State goes rogue too, granting the banking supervisory body the exceptional right to administer criminal justice. Following Boltanski (2011), our analysis explains these exception-to-the-rule behaviors by the contradictory logics that drive them. Two logics are identified in the financial sphere: the market logic, and the prudence logic. We highlight that fraud, and more generally the exception-to-the-rule attitude, result from the ambivalence generated by the coexistence of these contradictory logics of action, which are notably conveyed through control mechanisms. The study concludes that the State has a major role to play in this respect. More specifically, we raise the point that the neoliberal style of the penal State contributes to the occurrence of fraud
Mathematical modeling of COVID-19 pandemic in the context of sub-Saharan Africa: a short term forecasting in Cameroon and Gabon
No full textInternational audienceIn this paper, we propose and analyze a compartmental model of COVID-19 to predict and control the outbreak. We first formulate a comprehensive mathematical model for the dynamical transmission of COVID-19 in the context of sub-Saharan Africa. We provide the basic properties of the model and compute the basic reproduction number R 0 when the parameter values are constant. After, assuming continuous measurement of the weekly number of newly COVID-19 detected cases, newly deceased indivijduals and newly recovered individuals, the Ensemble of Kalman filter (EnKf) approach is used to estimate the unmeasured variables and unknown parameters which are assumed to be time-dependent using real data of COVID-19. We calibrated the proposed model to fit the weekly data in Cameroon and Gabon before, during and after the lockdown. We present the forecasts of the current pandemic in these countries using the estimated parameter values and the estimated variables as initial conditions. During the estimation period, our findings suggest that R 0 ≈ 1.8377 in Cameroon, while R 0 ≈ 1.0379 in Gabon meaning that the disease will not die out without any control measures in theses countries. Also, the number of undetected cases remains high in both countries, which could be the source of the new vague of COVID-19 pandemic. Short-term predictions firstly show that one can use the EnKf to predict the COVID-19 in Sub-Saharan Africa an
Geometry and Segmentation of Cerberus Fossae, Mars: Implications for Marsquake Properties
No full textInternational audienceThe NASA InSight mission to Mars successfully landed on November 26th, 2018 in Elysium Planitia. It aims to characterize the seismic activity and aid in the understanding of the internal structure of Mars. We focus on the Cerberus Fossae region, a giant fracture network ~1200 km long situated east of the InSight landing site where M~3 marsquakes were detected during the past two years. It is formed of five main fossae located on the southeast of the Elysium Mons volcanic rise. We perform a detailed mapping of the entire system based on high resolution satellite images and Digital Elevation Models. The refined cartography reveals a range of morphologies associated with dike activity at depth. Width and throw measurements of the fossae are linearly correlated, suggesting a possible tectonic control on the shapes of the fossae. Widths and throws decrease toward the east, indicating the long-term direction of propagation of the dike-induced graben system. They also give insights into the geometry at depth and how the possible faults and fractures are rooted in the crust. The exceptional preservation of the fossae allows us to detect up to four scales of segmentation, each formed by a similar number of 3-4 segments/subsegments. This generic distribution is comparable to continental faults and fractures on Earth. We anticipate higher stress and potential for marsquakes within intersegment zones and at graben tips
Les hérésies de la RSE en contexte africain: Une analyse au prisme des TPE
No full textInternational audienceThe objective of this study is to highlight the conception and interpretation of corporate social responsibility (CSR) in very small enterprises (VSEs) in a specific cultural environment representative of most African countries. The exploratory analysis revealed four profiles of leaders: the orthodox, the heretics, the semi-heretics-C and the semi-heretics-I. On the basis of these results, it would be possible to consider, depending on the managerial situation and culture, a CSR with African standards that favors "communitarianism" in the face of situational parameters.L’objectif de cette étude est de mettre en évidence la conception et l’interprétation de la responsabilité sociale des entreprises (RSE), dans les très petites entreprises (TPE), dans un environnement culturel spécifique représentatif de celui de la plupart des pays de l’Afrique. Il ressort de l’analyse exploratoire quatre profils de dirigeants : les orthodoxes, les hérétiques, les semi-hérétiques-C et les semi-hérétiques-I. Sur la base de ces résultats, il serait envisageable de penser, selon la donne managériale et la culture, à une RSE aux normes africaines militant en faveur d’un « communautarisme » face aux paramètres situationnels
A combined field study of Buruli ulcer disease in southeast Benin proposing preventive strategies based on epidemiological, geographic, behavioural and environmental analyses
No full textInternational audienceBuruli ulcer is a neglected tropical disease caused by M. ulcerans, an environmental mycobacterium. This cutaneous infectious disease affects populations with poor access to sanitation, safe water and healthcare living in rural areas of West and Central Africa. Stagnant open bodies of surface water and slow-running streams are the only risk factor identified in Africa, and there is no human-to-human transmission. Appropriate and effective prevention strategies are required for populations living in endemic areas. Based on a multidisciplinary approach in an area in which Buruli ulcer is endemic in South Benin, we investigated the link between all human-environment interactions relating to unprotected water and behaviors associated with Buruli ulcer risk likely to affect incidence rates. We characterised the sources of water as well as water bodies and streams used by communities, by conducting a prospective case-control study directly coupled with geographic field observations, spatial analysis, and the detection of M. ulcerans in the environment. A full list of the free surface waters used for domestic activities was generated for a set of 34 villages, and several types of human behaviour associated with a higher risk of transmission were identified: (i) prolonged walking in water to reach cultivated fields, (ii) collecting water, (iii) and swimming. Combining the results of the different analyses identified the risk factor most strongly associated with Buruli ulcer was the frequency of contact with unprotected and natural water, particularly in regularly flooded or irrigated lowlands. We confirm that the use of clean water from drilled wells confers protection against Buruli ulcer. These specific and refined results provide a broader scope for the design of an appropriate preventive strategy including certain practices or infrastructures observed during our field investigations. This strategy could be improved by the addition of knowledge about irrigation practices and agricultural work in low-lying areas
Potential areas of interest for the development of geothermal energy in La Réunion Island based on GIS analysis
No full textInternational audienceLa Réunion Island has been considered an attractive target for geothermal exploitation since the 1970s. However, to date, the island's geothermal resources are not being used. Here we use for the first time, a Geographic Information System (GIS) as a decision-making tool to target the most favorable zones for exploitation of moderate and high temperature geothermal resources. All data acquired since the 1970s (geology, geophysics, geochemistry) in addition to environmental constraints such as protection of the National Park that was recently classified as a UNESCO World Heritage Site, were analyzed using the weighted overlay method to delineate favorable areas for local geothermal exploration. Three thematic maps were constructed: geological and structural indicators, thermal indicators, and geophysical indicators. Cross-analysis of these maps highlights two zones that have high geothermal potential; six zones with unconfirmed geothermal potential; and two zones located within the National Park protected area and thus subject to stringent exploitation regulations. It appears that, while thermal anomalies exist in several areas, permeability of the geological formations is low or insufficient for traditional geothermal utilization. Future exploration phases should assess the feasibility of using enhanced geothermal system (EGS) technologies to obtain a satisfactory economic return
Identification of plant genetic resources affected by shrimp farming in the southwestern coastal region of Bangladesh
Get PDFThe main purpose of the study was to identify the plant genetic resources (PGRs) affected by shrimp farming and to determine their magnitude of vulnerability. Data were collected from randomly selected 100 respondents, through personal interview, using an interview schedule, at Dumuria upazila of Khulna district, during 16 November 2009 to 15 February 2010. The fruit PGRs were more affected by shrimp farming than that of timber yielding and other types of PGRs. Among the 18-fruit PGRs available, all were endangered, except indigenous velvet apple, Diospyros peregrine (Gaertn.) Gürke, which was in threatened condition. Among the fruit species, banana, Musa acuminate; guava, Psidium guajava L.; jackfruit, Artocarpus heterophyllus Lam.; sapota, Manilkara zapota L. and betel nut, Areca catechu L. were in highly endangered. Among the 17-timber yielding and other plant species, only 7-PGRs were affected by shrimp farming while majority (10-PGRs) had been available in different extents. Among the vulnerable PGRs, bamboo, Bambusa bambos (L.) Voss; flame of the forest, Delonix regia (Boj. ex Hook.) Raf.; teak, Tectona grandis L.f. and banyan, Ficus benghalensis L. were endangered, while Indian ash tree, Lannea coromandelica (Houtt.) Merr.; ipil-ipil, Leucaena leucocephala (Lam.) de Wit and cool mat, Schumannianthus dichotomus (Roxb.) Gagnep. were in threatened condition. In general, the total fruit trees decreased in numbers (-74.17%) after inception of shrimp farming. On the other hand, the total numbers of timber yielding plants increased by 15.45%. From the overall consideration (irrespective of types), the number of plant population decreased (-58.10%) after inception of shrimp farming. It means that the plant species were affected by shrimp farming and became endangered.
Int. J. Agril. Res. Innov. Tech. 11(2): 18-26, Dec 202
Molecular characterization and vegetative growth of pathogenic seed-borne fungus, Curvularia lunata of tomato and its in vitro control measures
Get PDFPresent studies were conducted to isolate and identify the seed-borne pathogenic fungus from the selected tomato variety through morphological and molecular techniques based on the sequencing of internal transcribed spacer (ITS) region of 18S rDNA. According to the colony and conidial features, the fungus was identified as Curvularia sp. The obtained ITS sequencing showed above 99% similarity with Curvularia lunata in the NCBI database. The sequence of the fungus was deposited in NCBI GenBank under the accession number: ITS, MH382879.1. Besides, the phylogenetic tree further confirmed the taxonomic position of the studied fungus. Growth characteristics of the fungus on nine different fungal culture media were evaluated, in which Honey peptone agar, Carrot agar, Potato sucrose agar, and Kauffman’s agar were found the most suitable. The maximum vegetative growth of the fungus was recorded at 30°C temperature and pH conditions. The bio-control potential of five different antagonists against the studied fungus was assessed, in which Trichoderma harzianum showed the better performance to restrict mycelial growth. Three ethanolic plant extracts were also evaluated, in which Lowsonia inermis L. exhibited above 60% mycelial growth inhibition of the fungus. Among three tested fungicides, Tilt 250 EC was found as an excellent fungicide to inhibit mycelial growth of C. lunata under in vitro conditions.
Int. J. Agril. Res. Innov. Tech. 11(2): 124-132, Dec 202
Effect of intercropping of maize and cowpea on the yield, land productivity and profitability of components crops in Bena- Tsemay Woreda, Southern Ethiopia
Get PDFField experiment was carried out during the 2017-18 cropping season at Kako, Bena-Ttsemay woreda, South Omo zone, Southern Ethiopia to determine the effect of intercropping of maize and cowpea on the yield, land use efficiency and profitability of both crops. The experiment consisted of 4 treatments (sole maize, sole cowpea, one row maize to one row cowpea and one row maize to two-row cowpea) and laid in RCBD in four replications. Intercropping of one row maize to one row cowpea and one row maize to two-row cowpea, resulted in 55.8% and 27.9% greater land use efficiency than for either crop grown alone. The highest MAI was obtained by growing one row of maize to one row of cowpea (11563.17) followed by one row maize to two-rows of cowpea (6783.50).Based on the present finding, intercropping of one row maize and one row cowpea more economic advantage than the other crop combination or grown alone. Therefore, intercropping of one row maize to one row cowpea is an advantageous to farmers in the study area since it would provide additional crop yield with the same piece of land and more profitable related to cost benefit.
Int. J. Agril. Res. Innov. Tech. 11(2): 147-150, Dec 202