Evaluation des Coupes-Rases Par la Télédétection et Les Systèmes d’Information Géographique dans la Forêt Classée de Djigbé (Bénin)

Le paysage des forêts classées étant de plus en plus anthropisé à cause de la pression démographique, optimiser le suivi du prélèvement du bois serait un défi pour la gestion rationnelle des forêts au sud Bénin. A cet effet, cette étude a pour objectif d’évaluer l’exploitation forestière faite par coupes-rases. Ce qui implique une estimation de l’évolution du massif forestier et donc de la disponibilité en bois pour une gestion planifiée et durable de la forêt classée de Djigbé (commune de Zè). La méthode utilisée relève de la télédétection et les Systèmes d’Information Géographique (SIG). Elle inclue la photo – interprétation par classification supervisée, le calcul de l’indice normalisée de végétation (NDVI) aboutissant à la restitution cartographique des coupesrases. Ainsi, la détection des coupes-rases a été suivie à partir des images satellitaires de type Landsat 8 des années 2014 à 2017. La détection automatisée des changements d’un état végétatif à un état non végétatif basée sur l’analyse de l’indice normalisé de la végétation (NDVI) entre deux dates a été utilisée. Des missions de géoréférencement des zones de coupes-rases dans la forêt classée de Djigbé ont aidé aux traitements des images à partir du logiciel ENVI 4.7. Les coupes-rases détectées ont par la suite été restituées par cartographie. Les résultats de détection des coupes-rases ont été statistiquement vérifiés par des matrices de confusion. Les emplacements de coupes-rases détectées pendant la période Décembre 2014-décembre 2015 diffèrent de celle de décembre 2015-janvier 2017. Chaque classe de coupe regroupée suivant un degré de certitude, respectant donc un cloisonnement donné. Ce qui renseigne sur la précision de la méthode automatisée de détection. La détection des coupes a été réalisée suivant trois valeurs de probabilité de présence de coupes-rases. Ces valeurs de probabilité sont : faible (1σ), moyenne (2σ) et forte (3σ) désignées par l’expression « degré de certitude ». Quelle que soit la classe et la période, le nombre de coupe est plus important chronologiquement pour le degré de certitude faible (1σ), moyenne (2σ) et forte (3σ). Les coupes-rases de détection supérieure ou égale à 1ha dans la plantation domaniale de Djigbé couvrent 234,63 ha. Ce qui induit une estimation de la disponibilité en bois qui est diminuée de cette même superficie détectée durant la période prise en compte par l’étude. Considérant le classement des coupes-rases suivant les degrés de certitude « moyenne » et « forte », sur l’ensemble des 234,63 ha, les proportions détectées ont été respectivement de 76 et de 24 %. La détection par images satellitaires et la cartographie est un outil de suivi et d’évaluation pertinent. Cet outil contribue à l’analyse périodique d’images satellitaires et la simulation de l’évolution de la ressource bois en plantation. Les résultats de cette étude permettent ainsi d’apprécier avec impartialité l’évolution du prélèvement et le suivi à distance de l’exploitation du bois. L’appropriation de l’utilisation de cet outil par les acteurs forestiers pour l’estimation de la ressource bois disponible, contribuerait à une meilleure gestion des forêts. The landscape of classified forests us being more and more anthropized because of demographic pressure. As a result, optimizing the monitoring of wood removal would be a challenge for the rational management of forests in southern Benin. This paper focuses on assessing logging done by clear-cutting. This implies an estimate of the evolution of the forest massif and therefore of the availability of wood for a planned and sustainable management of the classified forest of Djigbé (commune of Zè). The method used is based on remote sensing and Geographic Information Systems (GIS). It includes photo interpretation by supervised classification and the calculation of the standardized vegetation index (NDVI) leading to the cartographic restitution of the clear-cuts. Thus, the clearing detection was followed from Landsat 8 type satellite images from2014 to 2017. Automated detection of changes from a vegetative to a non-vegetative state based on the analysis of the index normalized vegetation (NDVI) between two dates was used. Georeferencing missions of clearcut areas in the classified forest of Djigbé helped image processing using the ENVI 4.7 software. The level cuts detected were subsequently restored by mapping. The shaving cutter detection results were statistically verified by confusion matrices. The clearing locations detected during the period December 2014 to December 2015 differ from that of December 2015 to January 2017. Each cutting class was grouped according to a degree of certainty, thus respecting a given partitioning. This provides information on the accuracy of the automated detection method. The detection of the cuts was carried out according to three values of probability of the presence of clear-cuts. These probability values are: low (1σ), medium (2σ), and high (3σ) designated by the expression "degree of certainty". Whatever the class and the period, the number of cuts is more important chronologically for the degree of certainty low (1σ), medium (2σ), and strong (3σ). The leveling shafts of detection greater than or equal to 1 ha in the national plantation of Djigbé cover 234.63 ha. This leads to an estimate of the availability of wood, which is reduced by the same area detected during the period taken into account by the study. Considering the classification of clearcuts according to the degrees of certainty "medium" and "strong", on the whole of the 234.63 ha, the proportions detected were respectively 76 and 24%. Detection by satellite images and mapping is a relevant monitoring and evaluation tool. This tool contributes to the periodic analysis of satellite images and the simulation of the evolution of the wood resource in plantation. The results of this study thus allow an impartial assessment of the evolution of the harvest and remote monitoring of logging. The appropriation of the use of this tool by forest stakeholders, for the estimation of the available wood resource, would contribute to better forest management

Rational approximation and arithmetic progressions

A reasonably complete theory of the approximation of an irrational by rational fractions whose numerators and denominators lie in prescribed arithmetic progressions is developed in this paper. Results are both, on the one hand, from a metrical and a non-metrical point of view and, on the other hand, from an asymptotic and also a uniform point of view. The principal novelty is a Khintchine type theorem for uniform approximation in this context. Some applications of this theory are also discussed

Proteolytic Processing of Nlrp1b Is Required for Inflammasome Activity

Nlrp1b is a NOD-like receptor that detects the catalytic activity of anthrax lethal toxin and subsequently co-oligomerizes into a pro-caspase-1 activation platform known as an inflammasome. Nlrp1b has two domains that promote oligomerization: a NACHT domain, which is a member of the AAA+ ATPase family, and a poorly characterized Function to Find Domain (FIIND). Here we demonstrate that proteolytic processing within the FIIND generates N-terminal and C-terminal cleavage products of Nlrp1b that remain associated in both the auto-inhibited state and in the activated state after cells have been treated with lethal toxin. Functional significance of cleavage was suggested by the finding that mutations that block processing of Nlrp1b also prevent the ability of Nlrp1b to activate pro-caspase-1. By using an uncleaved mutant of Nlrp1b, we established the importance of cleavage by inserting a heterologous TEV protease site into the FIIND and demonstrating that TEV protease processed this site and induced inflammasome activity. Proteolysis of Nlrp1b was shown to be required for the assembly of a functional inflammasome: a mutation within the FIIND that abolished cleavage had no effect on self-association of a FIIND-CARD fragment, but did reduce the recruitment of pro-caspase-1. Our work indicates that a post-translational modification enables Nlrp1b to function

Estimation of gestational age from fundal height: a solution for resource-poor settings

Many women in resource-poor settings lack access to reliable gestational age assessment because they do not know their last menstrual period; there is no ultrasound (US) and methods of newborn gestational age dating are not practised by birth attendants. A bespoke multiple-measures model was developed to predict the expected date of delivery determined by US. The results are compared with both a linear and a nonlinear model. Prospectively collected early US and serial symphysis-pubis fundal height (SFH) data were used in the models. The data were collected from Karen and Burmese women attending antenatal care on the Thai–Burmese border. The multiple-measures model performed best, resulting in a range of accuracy depending on the number of SFH measures recorded per mother (for example six SFH measurements resulted in a prediction accuracy of ±2 weeks). SFH remains the proxy for gestational age in much of the resource-poor world. While more accurate measures should be encouraged, we demonstrate that a formula that incorporates at least three SFH measures from an individual mother and the slopes between them provide a significant increase in the accuracy of prediction compared with the linear and nonlinear formulae also using multiple SFH measures

Efficient generation of energetic ions in multi-ion plasmas by radio-frequency heating

We describe a new technique for the efficient generation of high-energy ions with electromagnetic ion cyclotron waves in multi-ion plasmas. The discussed ‘three-ion’ scenarios are especially suited for strong wave absorption by a very low number of resonant ions. To observe this effect, the plasma composition has to be properly adjusted, as prescribed by theory. We demonstrate the potential of the method on the world-largest plasma magnetic confinement device, JET (Joint European Torus, Culham, UK), and the high-magnetic-field tokamak Alcator C-Mod (Cambridge, USA). The obtained results demonstrate efficient acceleration of 3He ions to high energies in dedicated hydrogen–deuterium mixtures. Simultaneously, effective plasma heating is observed, as a result of the slowing-down of the fast 3He ions. The developed technique is not only limited to laboratory plasmas, but can also be applied to explain observations of energetic ions in space-plasma environments, in particular, 3He-rich solar flares.This paper is dedicated to the late P. E. M. Vandenplas, founder and first director of LPP-ERM/KMS, in recognition of his lifelong outstanding commitment to fusion research, in particular to ICRH. The support from the JET and Alcator C-Mod Teams is warmly acknowledged. We are grateful to A. Cardinali, C. Castaldo, R. Dumont, J. Eriksson, T. Fülöp, C. Giroud, C. Hellesen, S. Menmuir and M. Schneider for fruitful discussions. This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014–2018 under grant agreement no. 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission. This work was also supported by the US DoE, Office of Science, Office of Fusion Energy Sciences, SciDAC Center for Simulation of Wave Plasma Interactions under DE-FC02-01ER54648 and the User Facility Alcator C-Mod under DE-FC02-99ER54512. The Alcator C-Mod Team author list is reproduced from ref. 12. The JET Contributors author list is reproduced from ref. 33.Peer ReviewedPostprint (author's final draft

Evaluation of Nod-Like Receptor (NLR) Effector Domain Interactions

Members of the Nod-like receptor (NLR) family recognize intracellular pathogens and recruit a variety of effector molecules, including pro-caspases and kinases, which in turn are implicated in cytokine processing and NF-κB activation