International Journal of Agricultural Research, Innovation and Technology (IJARIT)
International Journal of Agricultural Research, Innovation and Technology (IJARIT)Not a member yet
12720 research outputs found
Sort by
GATA-1 Defects in Diamond-Blackfan Anemia: Phenotypic Characterization Points to a Specific Subset of Disease
No full textInternational audienceDiamond-Blackfan anemia (DBA) is one of the inherited bone marrow failure syndromes marked by erythroid hypoplasia. Underlying variants in ribosomal protein (RP) genes account for 80% of cases, thereby classifying DBA as a ribosomopathy. In addition to RP genes, extremely rare variants in non-RP genes, including GATA1, the master transcription factor in erythropoiesis, have been reported in recent years in patients with a DBA-like phenotype. Subsequently, a pivotal role for GATA-1 in DBA pathophysiology was established by studies showing the impaired translation of GATA1 mRNA downstream of the RP haploinsufficiency. Here, we report on a patient from the Dutch DBA registry, in which we found a novel hemizygous variant in GATA1 (c.220+2T>C), and an Iranian patient with a previously reported variant in the initiation codon of GATA1 (c.2T>C). Although clinical features were concordant with DBA, the bone marrow morphology in both patients was not typical for DBA, showing moderate erythropoietic activity with signs of dyserythropoiesis and dysmegakaryopoiesis. This motivated us to re-evaluate the clinical characteristics of previously reported cases, which resulted in the comprehensive characterization of 18 patients with an inherited GATA-1 defect in exon 2 that is presented in this case-series. In addition, we re-investigated the bone marrow aspirate of one of the previously published cases. Altogether, our observations suggest that DBA caused by GATA1 defects is characterized by distinct phenotypic characteristics, including dyserythropoiesis and dysmegakaryopoiesis, and therefore represents a distinct phenotype within the DBA disease spectrum, which might need specific clinical management
Suivi de la dynamique forêt-savane dans la zone de transition guinéo-congolaise de la région Centre du Cameroun
No full textUnderstanding the effects of global change (combining anthropic and climatic pressures) on biome distribution needs innovative approaches allowing to address the large spatial scales involved and the scarcity of available ground data. Characterizing vegetation dynamics at landscape to regional scale requires both a high level of spatial detail (resolution), generally obtained through precise field measurements, and a sufficient coverage of the land surface (extent) provided by satellite images. The difficulty usually lies between these two scales as both signal saturation from satellite data and ground sampling limitations contribute to inaccurate extrapolations. Airborne laser scanning (ALS) data has revolutionized the trade-off between spatial detail and landscape coverage as it gives accurate information of the vegetation’s structure over large areas which can be used to calibrate satellite data. Also recent satellite data of improved spectral and spatial resolutions (Sentinel 2) allow for detailed characterizations of compositional gradients in the vegetation, notably in terms of the abundance of broad functional/optical plant types. Another major obstacle comes from the lack of a temporal perspective on dynamics and disturbances. Growing satellite imagery archives over several decades (45 years; Landsat) and available computing facilities such as Google Earth Engine (GEE) provide new possibilities to track long term successional trajectories and detect significant disturbances (i.e. fire) at a fine spatial detail (30m) and relate them to the current structure and composition of the vegetation. With these game changing tools our objective was to track long-term dynamics of forest-savanna ecotone in the Guineo-Congolian transition area of the Central Region of Cameroon with induced changes in the vegetatio structure and composition within two contrasted scenarios of anthropogenic pressures: 1) the Nachtigal area which is targeted for the dam construction and subject to intense agricultural activities and 2) the Mpem et Djim National Park (MDNP) which has no management plan. The maximum likelihood classification of the Spot 6/7 image aided with the information from the canopy height derived from ALS data discriminated the vegetation types within the Nachtigal area with good accuracy (96.5%). Using field plots data in upscaling aboveground biomass (AGB) form field plots estimates to the satellite estimates with model-based approaches lead to a systematic overestimation in AGB density estimates and a root mean squared prediction error (RMSPE) of up to 65 Mg.ha−1 (90%), whereas calibration with ALS data (AGBALS) lead to low bias and a drop of ~30% in RMSPE (down to 43 Mg.ha−1, 58%) with little effect of the satellite sensor used. However, these results also confirm that, whatever the spectral indices used and attention paid to sensor quality and pre-processing, the signal is not sufficient to warrant accurate pixel wise predictions, because of large relative RMSPE, especially above (200–250 Mg.ha−1). The design-based approach, for which average AGB density values were attributed to mapped land cover classes, proved to be a simple and reliable alternative (for landscape to region level estimations), when trained with dense ALS samples. AGB and species diversity measured within 74 field inventory plots (distributed along a savanna to forest successional gradient) were higher for the vegetation located in the MDNP compared to their pairs in the Nachtigal area. The automated unsupervised long-term (45 years) land cover change monitoring from Landsat image archives based on GEE captured a consistent and regular pattern of forest progression into savanna at an average rate of 1% (ca. 6 km².year-1). No fire occurrence was captured for savanna that transited to forest within five years of monitoring. Distinct assemblages of spectral species are apparent in forest vegetation which is consistent with the age of transition. As forest gets older AGBALS recovers at a rate of 4.3 Mg.ha-1.year-1 in young forest stands (45 ans ; Landsat) de même que l’avènement des méthodes de traitements automatiques tels que Google Earth Engine (GEE) offrent de nouvelles possibilités dans le suivi à long terme des trajectoires de succession à une fine résolution spatiale (30 m) et les relier à la structure et la composition de la végétation. À l’aide de ces outils révolutionnaires l’objectif de cette étude a été de caractériser la dynamique de la végétation dans l’écotone forêt-savane de la zone de transition Guinéo-Congolaise de la région du Centre Cameroun en lien avec deschangements induits sur la structure et la composition de la végétation dans la zone de construction du barrage hydroélectrique de Nachtigal et le parc national du Mpem et Djim (PNMD). La classification supervisée avec l’algorithme de maximum de vraisemblance d’une image du satellite Spot 6/7 complété par les informations sur la hauteur de canopée dérivée des données ALS a servi à discriminer les types de végétation dans la zone de Nachtigal avec une grande précision (96,5%). L’utilisation des données de terrain afin d’estimer la biomasse aérienne ligneuse (AGB) pour la zone de Nachtigal à partir d’un modèle statistique (model-based approach) calibré sur les données satellitaires a conduit à une surestimation systématique des estimations d’AGB avec une erreur résiduelle moyenne des prédictions (RMSPE) allant jusqu’à 65 Mg.ha−1 (90%), tandis que l’utilisation les données ALS (AGBALS) a conduit à un faible biais et une réduction du RMSPE d’environ 30 % (43 Mg.ha−1, 58%) avec un faible effet du type de satellite utilisé. Cependant ces résultats confirment également qu’une attention particulière doit être portée sur la qualité du capteur et le prétraitement des images pour tous les satellites. Le signal du satellite ne garantit pas une précision dans les estimations à l’échelle du pixel au-delà de 200–250 Mg.ha−1 à cause des valeurs élevées du RMSPE relatif. L’approche basée sur la conception (design-based approach) pour laquelle les valeurs moyennes d’AGB sont attribuées aux différents types de végétation constitue une alternative simple et fiable pour des estimations d’AGB à l’échelle du paysage pour des données ALS distribuées dans lesdifférentes typologies. L’AGB et a diversité spécifique mesurées au sein de 74 parcelles d’inventaires (distribuées le long d’un gradient de succession de la savane vers la forêt) sont élevées pour les végétations localisées dans le PNMD comparées aux végétations semblables échantillonnées à Nachtigal. L’approche automatique non supervisée du suivi à long terme (45 ans) des changements de couvert à partir d’archives Landsat dans GEE a mesuré un avancementconstant et régulier de la forêt sur la savane à une vitesse moyenne d’environ 6 km².an-1. L’archive d’image Landsat est la mieux appropriée pour le suivi de la fréquence des feux dans la zone d’étude en comparaison avec les produits MODIS. Entre deux périodes de monitoring successifs (5 ans) les pixels de savane avant la transition vers la forêt n’ont enregistré aucun évènement de feu. Des assemblages distincts d’espèces spectrales (β-diversity) sont apparents en forêt et sont corrélés avec l’âge de la transition. L’accumulation de l’AGBALS avec l’âge de la forêt est de of 4,3 Mg.ha-1.an-1 pour les jeunes forêts (< 20 ans) contre of 3.2 Mg,ha-1.an-1 pour les vieilles successions forestières (≥ 20 ans). En savane deux modes ont été identifiés le long du gradient de groupes spectraux correspondant aux niveaux AGBALS où la savane boisée associée à une faible fréquence de feu stocke 50 % plus de carbone que les savanes ouvertes dominées par les graminées qui ont une fréquence de feu élevée. Une occurrence de feu en 5 ans est nécessaire pour limiter le boisement de la savane. Nous avons décrit quatre communautés végétales suivant un gradient de transition et d’historique de feu. Cependant la présence d’espèces forestières dans des parcelles avec une fréquence de feux faibles suggèrerait l’inefficacité du feu dans la limitation du boisement de la savane. Ces résultats ont des fortes implications pour la séquestration du carbone et les politiques de conservation de la biodiversité. Le maintien des écosystèmes de savane dans la région va nécessiter des méthodes de gestion appropriées et sont contradictoires aux objectifs de reforestations (REDD+, Bonn challenge, etc.)
Politique budgétaire, Investissement privé et performance macroéconomique en République démocratique du Congo *
No full textWorking paperCe papier tente d'apprécier l'incidence de la politique budgétaire sur l'investissement privé et la croissance économique en R.D. Congo de 1990-2018. Dans ce sens, il évalue l'intensité du multiplicateur Budgétaire afin de statuer sur mécanisme budgétaire de quelques sous périodes. Une régression simple servira à cette fin. Nous estimons, comme Katuala (2020), un modèle de Vecteurs Autorégressifs structurels sous l'approche Bayésienne (B-SVAR) pour vérifier l'effet d'éviction et la dynamique macroéconomique sur les séries trimestrielles obtenues après désagrégation (Denton, 1971). La causalité de Granger (1980) et la cointégration de Johansen (1991) permettront de statuer sur les liens entre variables alors que l'identification des chocs du modèle s'inspire des travaux de Binning (2013) qui combinent les restrictions de signes et de zéros tant à court terme qu'à long terme dans le cadre de modèles VAR structurels sousidentifiés. Nos résultats ont révélé que : (i) Le multiplicateur budgétaire est très faible mais significatif. Ce qui pourrait justifier la faible force impulsive des investissements publics sur l'activité économique en R.D. Congo ; (ii) les chocs sur le Dépenses publiques n'ont pas donné des retombées escomptées sur la croissance économique ; (iii) les cours du cuivre sont restés rigides. Ce qui prouve que la R.D. Congo est un petit pays face à la scène internationale et (iv) Les investissements privés réagissent positivement aux soldes budgétaires et dépenses en capital du gouvernement congolais. Cette relation réfute l'hypothèse d'effet d'éviction
Learning Meta-features for AutoML
No full textInternational audienceThis paper tackles the AutoML problem, aimed to automatically select an ML algorithm and its hyper-parameter configuration most appropriate to the dataset at hand. The proposed approach, MetaBu, learns new meta-features via an Optimal Transport procedure, aligning the manually designed meta-features with the space of distributions on the hyper-parameter configurations. MetaBu meta-features, learned once and for all, induce a topology on the set of datasets that is exploited to define a distribution of promising hyper-parameter configurations amenable to AutoML. Experiments on the OpenML CC-18 benchmark demonstrate that using MetaBu meta-features boosts the performance of state of the art AutoML systems, (Feurer et al. 2015) and Probabilistic Matrix Factorization (Fusi et al. 2018). Furthermore, the inspection of MetaBu meta-features gives some hints into when an ML algorithm does well. Finally, the topology based on MetaBu meta-features enables to estimate the intrinsic dimensionality of the OpenML benchmark w.r.t. a given ML algorithm or pipeline
Note on the typification and synonymy of Cynorkis coccinelloides (Frapp.) Schltr., C. trilinguis (Frapp.) Schltr. and C. flexuosatis (Thouars) Hermans (Orchidaceae, Orchidoideae, Habenariinae)
No full textInternational audienceMost species of the genus Cynorkis are found on the Western Indian Ocean Islands. The correct taxonomic status of many species in this genus is not clear or is unresolved due to poor or lost type specimens, coupled with short protologue descriptions. Here, we lectotypify Cynorkis coccinelloides (Frapp.) Schltr. and show that C. brachycentra (A.Rich.) ex. Kraenzl.is a synonym of C. trilinguis (Frapp.) Schltr.. Moreover, C. flexuosatis (Thouars) Hermans, a Mauritian endemic, and C. trilinguis, a Réunion endemic, are different species. These clarifications are important to correct the taxonomic reference for the Mascarene flora, and to support any necessary conservation work
Devenir néonatal des retards de croissance intra-utérin sévères diagnostiqués in utéro, nés avant 32 semaines d'aménorrhée. Quelle information donner aux parents en anténatal ?
No full textBackground: Mortality and complications rates vary between studies of intrauterine growth restriction. It is essential to inform parents about the outcome of children diagnosed in utero with severe and early intrauterine growth retardation.Method: This retrospective study conducted in Réunion Island on 81 live births between 24 and 32 weeks with a birth weight below the 3rd percentile between January 2016 and June 2021, aimed to estimate the intra-hospital mortality and morbidity of these newborns according to the term of birth and the time of prenatal diagnosis.Results: 32% of newborns died. 100% of those born before 26 weeks, 41% born between 26 and 27 weeks, 24% born between 28 and 29 weeks and 4% born between 30 and 31 weeks. The mortality rate was higher for newborns diagnosed in utero between 24 and 26 weeks (45%) compared to those diagnosed between 18 and 21 weeks (13%). Newborns diagnosed between 24 and 26 weeks were born on average one week earlier (at 27 weeks) than those diagnosed earlier. Severe bronchopulmonary dysplasia was found in 36% of surviving babies born at 26-27 weeks, 29% of those born at 28-29 weeks and 9% of those born after 30 weeks. Optic retinopathy (stage 3 or more) affected 17% of surviving infants born at 26-27 weeks, 5% of those born at 28-29 weeks. Enterocolitis, leukomalacia and intraventricular hemorrhages were only found before 28 weeks.Conclusion: It is essential to adapt the information given to parents to the term of birth. Survival without severe neonatal morbidity increases from 17% before 28 weeks to 87% after 30.Introduction : Les taux de mortalité et de complications varient énormément entre les études s'intéressant au retard de croissance intra-utérin. Il est indispensable d'informer au mieux les parents sur le devenir des enfants diagnostiqués in utéro retard de croissance intra-utérin sévère et précoce.Méthode: Cette étude rétrospective menée à la Réunion sur 81 naissances vivantes entre 24 et 32 semaines avec un poids de naissance inférieur au 3e percentile entre janvier 2016 et juin 2021, cherchait à estimer la mortalité intra-hospitalière et la morbidité de ces nouveau-nés en fonction du terme de naissance et du moment du diagnostic prénatal.Résultats: 32% des nouveau-nés sont décédés. 100% de ceux nés avant 26 semaines, 41% nés entre 26 et 27 semaines, 24% nés entre 28 et 29 semaines et 4% nés entre 30 et 31 semaines. Le taux de mortalité était plus important pour les nouveau-nés diagnostiqués in utéro entre 24 et 26 semaines (45%) par rapport à ceux diagnostiqués entre 18 et 21 semaines (13%). Les nouveau-nés diagnostiqués entre 24 et 26 semaines naissaient en moyenne une semaine plus tôt (à 27 semaines) que ceux diagnostiqués avant. La dysplasie bronchopulmonaire sévère était retrouvée chez 36% des nouveau-nés survivants nés entre 26 et 27 SA, 29% de ceux nés entre 28 et 29 semaines et 9% pour ceux nés après 30 semaines. La rétinopathie optique (stade 3 ou plus) touchait 17% des nouveau-nés survivants nés entre 26 et 27 semaines, 5% de ceux nés entre 28 et 29 semaines. L'entérocolite, la leucomalacie et les hémorragies intraventriculaires étaient retrouvées uniquement avant 28 semaines. Conclusion: Il est essentiel d'adapter l'information donnée aux parents au terme de naissance. La survie sans morbidité néonatale sévère évolue entre 17% avant 28 semaine et 87% après 30
Along-Dip Segmentation of the Slip Behavior and Rheology of the Copiapó Ridge Subducted in North-Central Chile
No full textInternational audienceWe studied the along-dip influence of the Copiapó ridge subduction in the Atacama region, North-Central Chile by building a new seismicity catalog, including similar events and non-volcanic tremors (NVTs). We also obtained a 3-D tomographic model for P and S-waves velocity (and the implied Vp/Vs ratio). We identify along-dip segmentation involving four distinct segments: a locked seismogenic zone hosting ordinary seismicity and clusters of similar events; a transition zone with NVTs and low seismicity; an aseismic zone with slow-slip events; and a deep zone with abundant intraslab seismicity. The velocity models show differences among these zones, with low velocity anomalies of Vp and Vs coinciding with aseismic slip zones, indicating the possible presence of fluids. Due to the spatial distribution along-strike and along-dip of the aseismic zones, we propose that these differences in seismogenic behavior are generated by subduction of the heterogeneous seamounts associated with the Copiapó ridge
First Expert Elicitation of Knowledge on Drivers of Emergence of Bovine Besnoitiosis in Europe
No full textInternational audienceBovine besnoitiosis (BB) is a chronic and debilitating parasitic disease in cattle caused by the protozoan parasite Besnoitia besnoiti. South European countries are affected and have reported clinical cases of BB. However, BB is considered as emerging in other countries/regions of central, eastern and northern Europe. Yet, data on drivers of emergence of BB in Europe are scarce. In this study, fifty possible drivers of emergence of BB in cattle were identified. A scoring system was developed per driver. Then, the scoring was elicited from eleven recognized European experts to: (i) allocate a score to each driver, (ii) weight the score of drivers within each domain and (iii) weight the different domains among themselves. An overall weighted score was calculated per driver, and drivers were ranked in decreasing order of importance. Regression tree analysis was used to group drivers with comparable likelihoods to play a role in the emergence of BB in cattle in Europe. Finally, robustness testing of expert elicitation was performed for the seven drivers having the highest probability to play a key role in the emergence of BB: i.e., (i) legal/illegal movements of live animals from neighbouring/European Union member states or (ii) from third countries, (iii) risk of showing no clinical sign and silent spread during infection and post infection, (iv) as a consequence, difficulty to detect the emergence, (v) existence of vectors and their potential spread, (vi) European geographical proximity of the pathogen/disease to the country, and (vii) animal density of farms. Provided the limited scientific knowledge on the topic, expert elicitation of knowledge, multi-criteria decision analysis, cluster and sensitivity analyses are very important to prioritize future studies, e.g., the need for quantitative import risk assessment and estimation of the burden of BB to evidence and influence policymaking towards changing (or not) its status as a reportable disease, with prevention and control activities targeting, firstly, the top seven drivers. The present methodology could be applied to other emerging animal diseases
Necesidad de dar una buena acogida a las mujeres extranjeras. Memorias de una separación (Flora Tristan)
No full textInternational audienceEdición crítica y bilingüe de dos textos de Flora Tristán (1803- 1844): Necesidad de dar una buena acogida a las mujeres extranjeras (primer ensayo escrito por la autora) y Memorias de una separación (escrito presentado durante el proceso judicial de separación de cuerpos que entabló la autora contra su marido André Chazal)
Implications of Underground Nuclear Explosion Cavity Evolution for Radioxenon Isotopic Composition
No full textInternational audienceIsotopic ratios of radioxenons sampled in the atmosphere or subsurface can be used to verify the occurrence of an underground nuclear explosion (UNE). Differences in the half-lives of radioactive xenon precursors and their decay-chain networks produce different time-dependent concentration profiles of xenon isotopes allowing isotopic ratios to be used for tracking UNE histories including estimating the time of detonation. In this study, we explore the potential effects of post-detonation cavity processes: precipitation of iodine precursors, gas seepage, and prompt venting on radioxenon isotopic evolution which influences UNE histories. Simplified analytical models and closed-form solutions yielding a potentially idealized radioactive decay/ingrowth chain in a closed and well-mixed system typically have limited application by not including the partitioning of the radionuclide inventory between a gas phase and rock melt created by the detonation and by ignoring gas transport from the cavity to host rock or ground surface. In reality, either subsurface transport or prompt release that is principally responsible for gas signatures violates the closed-system (or batch-mode) assumption. A closed-form solution representing time-dependent source-term activities is extended by considering the cavity partitioning process, slow seepage, and/or prompt release of gases from the cavity and applied to realistic systems