International Journal of Agricultural Research, Innovation and Technology (IJARIT)
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Distribution of invasive versus native whitefly species and their pyrethroid knock-down resistance allele in a context of interspecific hybridization
No full textInternational audienceThe invasion success of a species in an agrosystem is greatly influenced by environmental factors such as the use of insecticides, by the intrinsic evolutionary capabilities of the species, and also by interactions with resident species. On the island of La Réunion, the successive invasions of MEAM1 and MED whitefly species over the last 20 years have not only led an increased use of insecticides, but have also challenged the resident IO species. To trace the evolution of the 3 species, and the distribution of the kdr mutation (resistance to pyrethroid) in the para-type voltage-gated sodium channel, we genotyped 41 populations (using neutral nuclear markers) and look at the prevalence of the kdr allele. MEAM1 was predominantly present in agrosystems showing quasi fixation of the resistant kdr allele whereas IO was mainly in natural environments and did not have any resistant allele. Hybridization between the two former species was detected in low frequency but has not led to introgression of resistant alleles in the resident species so far. MED showed a limited distribution in agrosystems but all individuals displayed a resistant allele. These highly contrasting patterns of distribution and resistant mutations between invasive and resident whitefly species are further discussed
Fractional modeling of Hansen's disease (Leprosy) transmission dynamics
No full textInternational audienceIn this work, we study a mathematical model for the Hansen's disease (leprosy) transmission dynamics with both integer and fractional derivatives in the Caputo sense. After the model formulation, we compute the leprosy reproduction number R 0 and prove the existence of two steady states named the Leprosy-free equilibrium and the leprosy-endemic equilibrium which exists and is unique if and only if R 0 > 1. Using the general theory of Lyapunov, we prove the global asymptotic stability of both steady states, for both models. The existence and uniqueness of the solutions of the fractional model are proved using fixed point theory. We finally perform numerical simulations to validate our analytical results, as well as to evaluate the impact of varying the fractional-order parameter on the disease dynamics
Change is Inevitable, Progress is Optional: Impact of FED Tapering Announcements on North African Equity Markets
No full textInternational audienceWe propose one of the first empirical evaluations of the transmission of the 2013-2015 Federalreserve Tapering announcements associated to assets purchases, to the stock markets of the three north African countries with the most advanced financial development: Egypt, Morocco, and Tunisia. We use two alternative announcement effects dummy variables: one constructed from econometric tests of individual announcements, the other constructed from the media coverage study. In spite of a relatively low level of financial integration, the results of panel data tests show a significant negative impact of announcements, generally associated with the Federal Open Market Committee (FOMC) meetings rather than minutes. This result is in line with the literature on the domestic and international announcement effects of the information released by the FOMC, in the absence of discordance of tone between the meeting statement and the minutes.From the perspective of policy recommendations, the study of the interaction of Tapering announcements with domestic fundamentals shows interesting results. Fundamentalswith favorable direct effects on equity markets dynamics could indirectly increasetheir vulnerability to announcement effects. Inflation, domestic investment and commercial openness show significant interaction effects in the opposite sense of their direct effects, some of which are superior to the direct effects
Tracking changes in social-ecological systems along environmental disturbances with the ocean health index
No full textInternational audienceThis is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain
Brillouin scattering in aluminosilicate glasses and melts up to 2550 K. Temperature and composition effects
No full textInternational audienceHypersonic sound velocities have been measured by Brillouin scattering for glasses and liquids of the system CaO-MgO-Al2O3-SiO2 (CMAS). Transverse wave velocities are reported for ten samples from 293 up to temperatures ranging from 1000 to 1600 K, depending on composition, and longitudinal velocities for six samples from 293 to the interval 1890-2360 K. For the 13 CMAS compositions, the temperature dependences of acoustic velocities are constant within three temperature intervals: (i) from 293 K to the standard glass transition temperature Tg, (ii) from Tg, to the temperature Trx of the onset of structural relaxation at the timescale of Brillouin scattering where transverse waves disappear, (iii) and finally above Trx where only longitudinal waves thus remain observed. The implications of these results for structural relaxation, shear-wave propagation and shear modulus are then discussed
Nickel and Chromium Stable Isotopic Composition of Ureilites: Implications for the Earth's Core Formation and Differentiation of the Ureilite Parent Body
No full textInternational audienceWe report the first Ni and Cr stable isotope data for ureilite meteorites that are the mantle residue of a carbon-rich differentiated planet. Ureilites have similar Ni stable isotope compositions as chondrites, suggesting that the core-mantle differentiation of ureilite parent body (UPB) did not fractionate Ni isotopes. Since the size of Earth is potentially larger than that of UPB; with diameter >690 km), resulting in higher temperatures at the core-mantle boundary of Earth, it can be predicted that the terrestrial core formation may not directly cause Ni stable isotope fractionation. On the other hand, we also report high-precision Cr stable isotope composition of ureilites, including one ureilitic trachyandesite (ALM-A) that is enriched in lighter Cr stable isotopes relative to the main-group ureilites, which suggests that the partial melting occurred on UPB. The globally heavy Cr in the UPB compared to chondrites can be caused by sulfur-rich core formation processes
Analyse des manifestations pulmonaires de la dengue lors de l'épidémie de 2019 sur l'île de La Réunion
No full textBackground. – Dengue fever is an arbovirus passed on by mosquitoes Aedes. Than half of mondial population is exposed. La Réunion Island has seen it’s dengue fever incidence increase strongly since 2018. We aimed to describe the clinical pulmonary manifestations and biological and imaging findings associated with patients presenting dengue fever during the 2019 epidemic in Réunion Island and compare the characteristics of the population with and without lung involvement.Methods. – This was an observational, monocentric, retrospective cohort study, including all cases of clinical dengue fever with positive RT-PCR within La Réunion University Hospital Center between January 2019 and June 2019.Results. – 847 patients were included in our study. 46 presented with pulmonary manifestations. 58.7% of patients with pulmonary manifestations met the 2009 WHO criteria for severe dengue fever versus 17.2% without pulmonary manifestation (p<0.0001). Twenty-nine chest scans were proof- read, 19 of which were considered abnormal with 31.5% presenting with ground glass, 47.4% with parenchymal condensation, 47.4% with pleural effusions and 10.5% with pulmonary embolism.Conclusion. – The pulmonary manifestations of dengue fever are rare, but are in our study a marker of disease severity. Lesions identified in chest CT images were consistent with those found in the literature.Contexte. – La dengue est une arbovirose transmise par le moustique Aedes. Plus de la moitié de la population mondiale y est exposée. L’île de La Réunion a vu son incidence augmenter fortement depuis 2018. L’objectif de cette thèse est de décrire les manifestations pulmonaires cliniques, biologiques et scannographiques des patients atteints de dengue lors de l’épidémie de 2019 sur l’île de La Réunion et de comparer les caractéristiques de la population avec et sans atteinte pulmonaire.Méthodes. – Étude de cohorte observationnelle, rétrospective monocentrique incluant tous les cas de dengue clinique avec RT-PCR positive au sein du CHU de La Réunion entre janvier 2019 et juin 2019.Résultats. – 847 patients ont été inclus dans notre étude dont 46 avec atteinte pulmonaire. 58.7% des patients avec atteinte pulmonaire rentraient dans les critères OMS 2009 de dengue sévère contre 17.2% sans atteinte pulmonaire (p<0.0001). Vingt-neuf scanners thoraciques ont été relus dont 19 considérés comme anormaux avec 31.5% de verre dépoli, 47.4% de condensations parenchymateuses, 47.4% d’épanchements pleuraux et 10.5% d’embolies pulmonaires.Conclusion. – Les manifestations pulmonaires de la dengue sont rares, mais sont le marqueur dans notre étude d’une sévérité de la maladie. Les atteintes scannographiques retrouvées sont conformes à celles de la littérature
Aerosol Distributions and Sahara Dust Transport in Southern Morocco, from Ground-Based and Satellite Observations
No full textInternational audienceThe present study investigates aerosols distributions and a strong Sahara dust-storm event that occurred by early August 2018, in the South of Morocco. We used columnar aerosol optical depth (AOD), Angstrom Exponent (AE) and volume size distributions (VSD) as derived from ground-based observations by 2 AERONET (AErosol RObotic NETwork) sun-photometers at Saada (31.63°N, 8.16°W) and Ouarzazate (30.93°N, 6.91°W) sites, over the periods 2004–2019 and2012–2015, respectively. The monthly seasonal distributions of AOD, AE, and VSD showed a seasonal trend dominated by the annual cycle, with a maximum aerosol load during summer (July–August) and a minimum in winter (December–January), characterized by a coarse mode near the radius of 2.59 µm and a fine mode at the radius of 0.16 µm , respectively. Indeed, this study showed that aerosol populations in southern Morocco are dominated by Saharan desert dust, especially during the summer season. The latter can sometimes be subject of dust-storm events. The case study presented in this paper reports on one of these events, which happened in early August 2018. The HYSPLIT (HYbrid Single Particle Lagrangian Integrated Trajectory) model was used to simulate air-mass backtrajectories during the event. In agreement with ground-based (AERONET sun-photometers) and satellite (CALIOP, MODIS and AIRS) observations, HYSPLIT back-trajectories showed that the dust air-mass at the 4-km layer, the average height of the dust plume, has crossed southern Morocco over the Saada site, with a westward direction towards the Atlantic Ocean, before it changed northward up to the Portuguese coasts
L’engagement scolaire des élèves de SEGPA en dispositif d’inclusion
No full textInclusive education is one of the priorities of the French education system in order to guarantee equal opportunities. This inclusion is particularly important in the context of the adapted general and vocational education section, which suffers from many stereotypes. The effects of this inclusive education seem to be numerous and among them an impact on the school engagement of these students. This concept is complex and is composed of several dimensions: academic, psychological, cognitive and behavioral. It is then evaluated under the prism of academic motivation and peer relationships. Motivation, which is established under a spectrum, depends on several factors such as perceived competence or self-determination. It covers academic, psychological and cognitive dimensions. Peer relations assess the psychological dimension of academic engagement.L’inclusion scolaire est une des priorités du système éducatif français afin de garantir l’égalité des chances. Cette inclusion est tout particulièrement importante dans le cadre de la section d’enseignement général et professionnel adapté qui souffre de nombreux stéréotypes. Les effets de cette inclusion semblent être nombreux et parmi eux un impact sur l’engagement scolaire de ces élèves. Ce concept est complexe et se compose de plusieurs dimensions : académique, psychologique, cognitive et comportementale. Il est alors évalué sous le prisme de la motivation scolaire et des relations entre pairs. La motivation qui s’établit sous un spectre dépend de plusieurs facteurs tels que la compétence perçue ou l’autodétermination. Elle recouvre les dimensions académiques, psychologique et cognitive. Les relations entre pairs évaluent la dimension psychologique de l’engagement scolaire
Probabilistic analysis to correlate seismic data with lava extrusion phases at Merapi volcano (Indonesia)
No full textInternational audienceVolcanoes can produce a range of eruptive behavior even during a single eruption, changing quickly from effusive to explosive style, and the other way around. The changes in eruption phases (e.g. phreatic explosion, magmatic explosion, lava extrusion, etc.) can lead to different volcanic hazards and require timely assessment for the implementation of mitigation measures. Here we explore how to correlate a given eruption phase with changes in the monitoring data using statistical analysis and conditional probabilities. We calculate the success of detection of an eruption phase using a threshold of monitoring data, which includes the uncertainty on the eruption phase dates with a Monte Carlo simulation. We apply the method to dome forming eruptions of Mt. Merapi (Indonesia) and evaluate their time occurrence using an exceptionally long monitoring time series (from 1993 to 2012, over nineteen years) of Multiphase (Hybrid) Seismic Energy. We identify the seismic energy threshold that is associated with the lava extrusion phase with an accuracy of 90 ±2%, precision of 73 ± 2%, specificity of 96 ± 1%, and sensitivity of 56 ± 1%. We further test our method with the recent 2018 eruption (not used in the thresholds calculations) and we identify the lava extrusion with a precision of 67%, specificity of 70%, and sensitivity of 92%. We also seismically detected the 2018 ′ s onset of the lava extrusion phase 14 days earlier than the visual observation. Given the link between dome-collapse pyroclastic flows and growth episodes of the lava dome at Merapi, our analysis also allows us to establish that 83% of the most energetic pyroclastic flows occur within the first 3 months after the onset of lava extrusion phase. Our method can be applicable to a range of time series of monitoring data (seismic, deformation, gas) and to other volcanoes that have a significant number of past events