124 research outputs found
High throughput DNA barcoding to assess the diversity of Laurentian insects
La grande diversitĂ© dâinsectes et la quantitĂ© de spĂ©cimens recueillis lors de lâĂ©chantillonnage
constituent les plus grands défis de la systématique des insectes. Le tri des échantillons au
niveau des espĂšces est nĂ©cessaire avant quâils puissent ĂȘtre utilisĂ©s pour des enquĂȘtes sur les
modĂšles de biodiversitĂ©. En raison de lâobstacle taxonomique, le manque dâexpertise
taxonomique, de nombreuses études sur la diversité des insectes classe les spécimens en Unités
Morphologiques Opérationnelles (MorphOTUs), aussi appelées morpho-espÚces, en désignant
les groupes définis subjectivement en fonction de caractéristiques morphologiques évidentes.
Cependant, il est long et douteux de définir avec précision les limites des espÚces en se fondant
sur les MorphOTUs, surtout dans les groupes oĂč il y a de minuscules insectes et une grande
similaritĂ© au niveau des espĂšces, comme chez les HymĂ©noptĂšres. Le codage Ă barres de lâADN,
une approche taxonomique discriminatoire qui utilise des sĂ©quences dâADN, a accĂ©lĂ©rĂ© la
classification taxonomique et peut ĂȘtre une approche alternative aux MorphOTUs. Cependant,
il est crucial dâutiliser une stratĂ©gie fiable et Ă©conomique de codage Ă barres ADN pour traiter
un grand nombre dâĂ©chantillons. En outre, le codage Ă barres dâADN devrait fonctionner avec
les espĂšces problĂ©matiques dans lâentomologie molĂ©culaire comme on l'observe parfois avec
les hyménoptÚres.
Afin de mettre en Ćuvre une Ă©valuation rapide de la biodiversitĂ© des HymĂ©noptĂšres, optimiser
les de Ă©tapes de barcodage d`ADN (extraction dâADN, amplification par PCR et sĂ©quençage)
Ă©tait le premier objectif de ce projet de recherche. On a testĂ© et optimisĂ© une extraction dâADN
arrivant à une méthode coûtante 0,20 dollars par spécimen. On a validé la performance adéquate
des mini-codes Ă barres dâADN, rĂ©duits en taille Ă 313bp, pour Ă©tablir une classification
dâUnitĂ©s Taxonomiques OpĂ©rationnelles MolĂ©culaires (MOTUs) comparable Ă celle du codage
Ă barres dâADN couramment utilisĂ©, de longueur de 658bp. On a adoptĂ© ce protocole optimisĂ©
pour le codage Ă barres de 517 spĂ©cimens dâHymĂ©noptĂšres Ă©chantillonnĂ©s par des piĂšges
aspirateurs situĂ©s dans la forĂȘt laurentienne de lâEst du Canada. Avec le sĂ©quençage multiplexĂ©
à haut débit Illumina, impliquant des amplicons étiquetés, on a obtenu des mini-codes à barres
pour 88% des spécimens. Le coût et le temps nécessaires pour générer des données MOTU,
grĂące Ă notre approche de codage Ă barres dâADN, Ă©taient environ la moitiĂ© de celui de la
classification morphologique en MorphOTUs.
Le deuxiĂšme objectif de ma recherche Ă©tait de comparer lâefficacitĂ© du tri morphologique des
MorphOTUs avec lâidentification molĂ©culaire et la dĂ©limitation par MOTUs. On a dĂ©montrĂ©
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une forte congruence entre lâidentification morphologique et molĂ©culaire au niveau
taxonomique de la famille dansla base de données Barcode of Life (BOLD) et GenBank (93 %),
alors que seulement 18 % des mini-codes à barres ont été attribués à des identifications plus
prĂ©cises (genre ou espĂšce). La dĂ©limitation molĂ©culaire sâest faite avec quatre mĂ©thodes de
regroupement diffĂ©rentes (basĂ©e sur la distance : DĂ©couverte automatique de lâĂ©cart de codes Ă
barres (ABGD) et Assemblage des espÚces par partitionnement automatique (ASAP) ; basée
sur un dendrogramme : Coalescente mixte généralisée du yule (GMYC) et Processus bayésien
de lâarbre de poisson (bPTP)). En gĂ©nĂ©rale, les mĂ©thodes molĂ©culaires ont plus que doublĂ© la
diversité estimée des MorphOTUs des HyménoptÚres. Les MOTUs étaient en grande partie
incompatibles avec les MorphOTUs (ratio dâappariement <0,35). Les mĂ©thodes basĂ©es sur la
distance ont donné des résultats plus conformes au tri morphologique que les méthodes basées
sur les arbres, en particulier dans la superfamille des Chalcidoidea.
Compte tenu de la comparaison entre le coût et le temps des méthodes de classification
moléculaire et morphologique, nos résultats suggÚrent que le codage à barres mini-ADN pour
estimer la diversitĂ© des espĂšces dâHymĂ©noptĂšres est plus Ă©conomique que le tri par MorphOTU.
Cependant, bien que les méthodes MorphOTU et MOTU aient donné de nombres unités
taxonomiques différentes, les analyses de la diversité utilisées actuellement tiennent compte de
lâabondance et dâautres paramĂštres. On nâa pas Ă©valuĂ© si les MorphOTUs et les protocoles
dâentente donneraient des rĂ©sultats suffisamment Ă©quivalents dans la recherche rĂ©elle sur les
diversitĂ©s α et ÎČ, câest-Ă -dire pour Ă©valuer sâils pouvaient tout de mĂȘme tous deux ĂȘtre utiles.The great insect diversity and the quantity of insect specimens collected during sampling
constitute the biggest challenges facing insect systematics. Sorting samples to the species level
is necessary before they can be used for investigations of biodiversity patterns. Because of the
Taxonomic impediment, the lack of taxonomic expertise, many insect diversity studies sort
specimens to Morphological Operational Taxonomic Units (MorphOTUs), also known as
morphospecies, classifying subjectively defined groups based on obvious morphological
features. However, accurately defining species boundaries based on MorphOTUs is time
consuming and questionable, especially in groups with tiny insects and great species-level
similarity such as Hymenoptera. DNA barcoding, a taxonomic discriminatory approach that
employs DNA sequences, has accelerated taxonomic classification and may be an alternative
approach to MorphOTUs. However, it is crucial to use a reliable and economic DNA barcoding
strategy to deal with a large number of samples. Additionally, DNA barcoding should work
with species problematic in molecular entomology as is sometimes observed with
Hymenoptera.
In order to implement a rapid biodiversity assessment of Hymenoptera, optimizing the DNA
barcoding steps (DNA extraction, PCR amplification, and DNA sequencing) was the first
objective of this present research. We tested and optimized a DNA extraction arriving at a
method costing 0.20CAD per specimen. We validated the adequate performance of 313bp mini barcodes for establishing Molecular Operational Taxonomic Units (MOTUs) classification,
comparable to that of the commonly used full-length DNA barcode of 658bp. We adopted this
optimized protocol to barcode 517 Hymenoptera specimens sampled with suction traps located
in the Laurentian Forest of eastern Canada. With multiplexed Illumina high throughput
sequencing of tagged amplicons, we obtained mini-barcodes for 88% of specimens. The cost
and time taken to generate MOTU data through our DNA barcoding approach was
approximately twice that of morphological identification for MorphOTU designation.
The second objective of my research was to compare the efficacy of morphological sorting of
MorphOTUs with the molecular identification and delimitation of MOTUs. We found a high
taxonomic congruence between morphological and molecular identification at family level in
Barcode of Life (BOLD) and GenBank databases (93%), whereas only 18% of mini-barcode
data was assigned to more precise identification (genus or species). Molecular delimitation
based on four different clustering methods (distance-based: Automatic Barcode Gap Discovery
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(ABGD) and Assemble Species by Automatic Partitioning (ASAP); tree-based: Generalized
Mixed Yule Coalescent (GMYC) and Bayesian Poisson Tree Processes (bPTP)) resulted in
more than doubling the estimated diversity of Hymenoptera as compared to MorphOTUs. The
MOTUs were largely incongruent with MorphOTUs (match ratio <0.35). Distance-based
methods gave results more congruent with morphological sorting than tree-based methods,
especially within the Chalcidoidea superfamily.
Taking into account the comparison between the cost and time of molecular and morphological
classification methods, our results suggest that mini-DNA barcoding to estimate a proxy for
Hymenoptera species diversity is more economical than MorphOTU sorting. However,
although MorphOTU and MOTU methods gave different numbers of species, actual diversity
analyses take into account abundance and other parameters. We did not evaluate whether
MorphOTUs and MOTUs would yield sufficiently equivalent results in actual α- and ÎČ diversity research: that is, they may yet both be fit for purpos
Volatile and Non-Volatile Single Electron Memory
Multi Tunnel Junctions (MTJs) have attracted much attention recently in the ïŹelds of Single-Electron Devices (SED) in particular Single-Electron Memory (SEM). In this paper, we have design and study a nano-device structure using a two dimensional array MTJs for Volatile and Non-Volatile-SEM, in order to analyze the impact of physical parameters on the performances. We investigate the single-electron circuit characteristics in our devices qualitatively, using single-electron Monte Carlo simulator SIMON.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3192
Méthode d'analyse et de classification des segments du réseau routier supérieur de la région de Montréal
RĂSUMĂ
La congestion routiĂšre est un phĂ©nomĂšne gĂ©nĂ©ral, considĂ©rĂ©e comme une externalitĂ© extrĂȘmement coĂ»teuse (Prudâhomme, 1999). Elle a des effets nĂ©fastes sur la prospĂ©ritĂ© Ă©conomique dâun pays, le bien-ĂȘtre des individus et la stabilitĂ© de lâĂ©cosystĂšme. La comprĂ©hension de ce phĂ©nomĂšne est fondamentale afin que les autoritĂ©s du transport routier soient en mesure dâapporter des solutions appropriĂ©es Ă ce problĂšme. Ce mĂ©moire prĂ©sente la mĂ©thode dâanalyse et de classification des segments du rĂ©seau routier supĂ©rieur de la grande rĂ©gion montrĂ©alaise Ă partir de leurs caractĂ©ristiques physiques, puis Ă©tudie la similaritĂ© entre cette nouvelle classification et celle obtenue Ă partir des relevĂ©s de temps de parcours observĂ©s sur ces diffĂ©rents segments routiers durant la pĂ©riode de pointe du matin (AM). AprĂšs avoir recensĂ©, Ă lâissue dâune revue de littĂ©rature, les caractĂ©ristiques physiques des routes ayant un lien avec lâĂ©tat de la circulation, ce document met en avant la mĂ©thodologie proposĂ©e afin dâatteindre lâobjectif maĂźtre de ce mĂ©moire. Lâapproche proposĂ©e comporte 5 Ă©tapes : faire le montage de la base de donnĂ©es relationnelle, dresser le portrait global du rĂ©seau routier Ă©chantillonnĂ©, synthĂ©tiser et agrĂ©ger les donnĂ©es de facteurs physiques, grouper les tronçons selon leurs caractĂ©ristiques physiques, confronter les mĂ©thodes de groupement de tronçons et prĂ©dire lâappartenance dâun tronçon Ă un groupe TP Ă partir des facteurs physiques. Plusieurs outils ont Ă©tĂ© utilisĂ©s pour crĂ©er la base de donnĂ©es des facteurs physiques, tels que Google Maps, Street View et ArcGis. Le choix de caractĂ©ristiques physiques est fondĂ© sur de multiples Ă©tudes effectuĂ©es par divers auteurs sur la thĂ©matique de la congestion routiĂšre. Au moyen dâun logiciel de traitement de base de donnĂ©es, la table des facteurs physiques a Ă©tĂ© intĂ©grĂ©e avec deux autres tables qui proviennent directement des travaux de Loustau et al.(2009), soit la table des groupes TP et la table dâĂ©tat de la circulation. Ces travaux consistent Ă grouper les segments routiers de la grande rĂ©gion de MontrĂ©al selon les temps de parcours durant la pĂ©riode de pointe du matin (AM).
Une analyse descriptive de la base de donnĂ©es relationnelle qui vise Ă dresser le portait du rĂ©seau routier de la grande rĂ©gion de MontrĂ©al, a Ă©tĂ© menĂ©e. En effet, une qualification de lâĂ©tat de la circulation du rĂ©seau routier montrĂ©alais a Ă©tĂ©, au premier lieu, effectuĂ©. En second lieu, une analyse descriptive des facteurs physiques des tronçons routiers Ă©chantillonnĂ©s a Ă©tĂ© rĂ©alisĂ©e.-----------ABSTRACT Urban congestion is a general phenomenon, regarded as an extremely costly externality (Prud'homme, 1999). Indeed, congestion has adverse effects on the economy, society and the environment. The urban transportation authorities must understand the congestion phenomenon in order to provide adequate solutions to this problem. This report presents the method of analysis and classification of road segments of the Greater Montreal Region highway system based on their physical characteristics. It then compares this classification to the traffic condition of road sections according to the frequency distribution of travel times observed on these various road sections during the morning rush hour (AM). Following a definition of road congestion and of the indicators to measure it, this paper puts forward the proposed methodology to reach the main objective of this work. The approach is proposed in 5 different steps: to built the relational database, to make a global description of the sampled road system, to summarize and aggregate the data relating to physical factors, to cluster the different sections based on their physical characteristics, to compare the methods with which the sections were grouped together and to predict the TP group of section road. Several tools have been used to create the physical factors database, such as Google Maps, Street View and ArcGIS. The choice of physical characteristics is based on a number of studies carried out by various authors on the subject of urban congestion. Using database management software, the physical factors table has been combined with two other tables taken directly from work done by Loustau and al. (2009), i.e. the TP groups table and the traffic conditions table. These studies consisted in grouping the road sections of the Greater Montreal Region according to travel times during the morning rush hour (AM). A descriptive analysis of the relational database was carried out with the objective of drawing a global picture of the Greater Montreal Region road system. Thus a classification of traffic conditions on the Montreal road network was first made. Then, a descriptive analysis of the physical factors of the sampled road sections was made. Some characteristics turned out to prevail over others: the "highway" type of lanes, the maximum speed authorized, which varies between 70km/h and 100km/h, the very small number of intersections and the number of lanes, which varies between 2 and 3
About modeling and control strategies for scheduling crop irrigation
International audienceWe propose a new simplified crop irrigation model and study the optimal control which consists in maximizing the biomass production at harvesting time, under a constraint on the total amount of water used. Under water scarcity, we show that a strategy with a singular arc can be better than a simple bang-bang control as commonly used. The gain is illustrated on numerical simulations. This result is a promising first step towards the application of control theory to the problem of optimal irrigation scheduling
Phylogeographyc inferences from the mtDNA variation of the three-toed skink, Chalcides chalcides (Reptilia: Scincidae)
Genetic diversity was analyzed in Chalcides chalcides populations from peninsular Italy, Sardinia, Sicily and Tunisia by sequencing 400 bp at the 50 end of the mitochondrial gene encoding cytochrome b (cyt b) and by restriction fragment length polymorphism (RFLP) analysis of two mitochondrial DNA segments (ND-1/2 and ND-3/4). The results of the phylogenetic analysis highlighted the presence of three main clades corresponding with three of the four main geographical areas (Tunisia, Sicily and the Italian peninsula), while Sardinia proved to be closely related to Tunisian haplotypes suggesting a colonization of this island from North Africa by human agency in historical times. On the contrary, the splitting times estimated on the basis of cyt b sequence data seem to indicate a more ancient colonization of Sicily and the Italian Peninsula, as a consequence of tectonic and climatic events that affected the Mediterranean Basin during the Pleistocene. Finally, the analysis of the genetic variability of C. chalcides populations showed a remarkable genetic homogeneity in Italian populations when compared to the Tunisian ones. This condition could be explained by a rapid post-glacial expansion from refugial populations that implied serial bottlenecking with progressive loss of haplotypes, resulting in a low genetic diversity in the populations inhabiting the more recently colonized areas
Steady vs. Dynamic Contributions of Different Doped Conducting Polymers in the Principal Components of an Electronic Nose's Response
Multivariate data analysis and machine-learning classification become popular
tools to extract features without physical models for complex environments
recognition. For electronic noses, time sampling over multiple sensors must be
a fair compromise between a period sufficiently long to output a meaningful
information pattern, and sufficiently short to minimize training time for
practical applications. Particularly when reactivity's kinetics differ from
thermodynamics' in sensitive materials, finding the best compromise to get the
most from data is not obvious. Here, we investigate on the influence of data
acquisition to improve or alter data clustering for molecular recognition on a
conducting polymer electronic nose. We found out that waiting for the sensors
to reach their steady state is not required for classification, and that
reducing data acquisition down to the first dynamical information suffice to
recognize molecular gases by principal component analysis with the same
materials. Particularly for online inference, this study shows that a good
sensing array is no array of good sensors, and that new figure-of-merits shall
be defined for sensing hardware aiming machine-learning pattern-recognition
rather than metrology
Optimal control of membrane filtration systems
International audienceThis paper studies an optimal control problem related to membrane filtration processes. A generic mathematical model of membrane fouling is used to capture the dynamic behavior of the filtration process which consists in the attachment of matter onto the membrane during the filtration period and the detachment of matter during the cleaning period. We consider the maximization of the net water production of a membrane filtration system (i.e. the filtrate) over a finite time horizon, where the control variable is the sequence of filtration/backwashing cycles over the operation time of process. Based on the Pontryagin Maximum Principle, we characterize the optimal control strategy and show that it exhibits a singular arc. Moreover we prove the existence of an additional switching curve before reaching the terminal state, and also the possibility of having a dispersal curve as a locus where two different strategies are both optimal
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