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199 results on '"Labarre D"'

8. Survey of Trichogramma(Hymenoptera: Trichogrammatidae) Natural Populations in Quebec Cranberry Bogs and Identification Using rDNA ITS-2 Sequence Analysis

Author

Labarre, D, Drolet, I, Légaré, J -P, Breton, M, Cormier, D, and Lucas, E

Abstract

The province of Quebec, Canada is the most important organic cranberry growing region worldwide. However, insect pest management methods are limited, and growers face significant yield loss each year, mostly caused by lepidopteran pests. Egg parasitoids of the genus Trichogramma(Hymenoptera: Trichogrammatidae) are effective biocontrol agents of lepidopteran pests in many forests and agricultural systems. Herein, a two-year, large-scale population survey of Trichogrammaspp. was performed using Ephestia kuehniellaZeller (Lepidoptera: Pyralidae) as sentinel eggs in Quebec organic cranberry bogs. Collected specimens were identified by sequencing ribosomal DNA of the Internal Transcribed Spacer 2 (ITS-2) region and subjected to resemblance analysis with reference specimens for identification. Our results confirm that at least four Trichogrammaspecies naturally occur in the studied agroecosystem. Those species are T. brassicaeBezdenko, T. minutumRiley, T. ostriniae(Pang et Chen), and T. pretiosumRiley. While some species have already been reported in cranberry bogs, this represents the first mention of T. brassicaeand T. ostriniaeas well as the first mention of T. minutumin Quebec cranberry bogs. All species collected are native from Eastern Canada except T. ostriniae. These species can be considered as biocontrol agent candidates for cranberry lepidopteran pests, but further efficacy trials are needed to identify the best species for each pest.

Published
2022
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15. Polymeric Micro- and Nanoparticles as Drug Carriers

Author

Barratt, G, primary, Couarraze, G, additional, Couvreur, P, additional, Dubernet, C, additional, Fattal, E, additional, Gref, R, additional, Labarre, D, additional, Legrand, P, additional, Ponchel, G, additional, and Vauthier, C, additional

Published
2001
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23. Two Cross Coupled Kalman Filters for Joint Estimation of MC-DS-CDMA Fading Channels and Their Corresponding Autoregressive Parameters

Author

Ali Jamoos, Labarre, D., Grivel, E., Najim, M., and Grivel, Eric

Subjects
MC-DS-CDMA, [INFO.INFO-TS] Computer Science [cs]/Signal and Image Processing, Kalman filter, joint estimation, Computer Science::Information Theory, [SPI.SIGNAL] Engineering Sciences [physics]/Signal and Image processing
Abstract

This paper deals with the estimation and equalization of time-varying Rayleigh fading channels for synchronous Multi-Carrier Direct-Sequence Code Division Multiple Access (MC-DS-CDMA) systems. The approach we propose operates in three steps. Firstly, decorrelating filtering is carried out along each carrier to eliminate the Multiple Access Interference (MAI). Secondly, the fading channel responses, modelled by autoregressive (AR) processes, are estimated by using Kalman filtering. Nevertheless, since the AR parameters are also unknown, one has to estimate both the channels and the corresponding AR parameters. Avoiding a non linear approach such as the Extended Kalman Filter (EKF), the method we present is based on two cross coupled Kalman filters. Thirdly, the channel estimates are fed into a frequency diversity Maximal Ratio Combining (MRC) rule for channel equalization and symbol detection. The performances of the proposed approach are investigated under realistic Jakes' fading model with slow and fast fading scenarios.

Published
2005

25. Measure of the Regularity of Events in Stochastic Point Processes, Application to Neuron Activity Analysis

Author

BORDEAUX UNIV (FRANCE), Labarre, D., Meissner, W., Boraud, T., BORDEAUX UNIV (FRANCE), Labarre, D., Meissner, W., and Boraud, T.

Abstract

Numerous researches aim at understanding the high brain functions such as memory or decision making by analysing the activity of brain neurons. This activity corresponds to sequences of electrical potentials and thus can be viewed as a point processes. In this paper, we propose a method to measure the regularity level of event occurrences in point processes. Based on the analysis of the so-called density histogram, the proposed approach has the advantage of providing a decision to classify the process into one of the three following distinct classes: the "regular" processes, the "irregular" processes and the "bursting" processes. To illustrate the efficiency of the method, we first carry out a comparative study based on synthetic data. Then, the algorithm is tested in the framework of neurosciences for the classification of neurons according to their activity., See also ADM002091. Presented at the IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP 2008), Held in Las Vegas, Nevada on March 30-April 4, 2008. Government or Federal Purpose Rights License.. The original document contains color images.

Published
2008

28. Évolution du bassin et de la hanche « à travers les âges » : des primates à l’homme moderne

Author

Lapègue, F., primary, Jirari, M., additional, Sethoum, S., additional, Faruch, M., additional, Barcelo, C., additional, Moskovitch, G., additional, Ponsot, A., additional, Rabat, M.-C., additional, Labarre, D., additional, Vial, J., additional, Chiavassa, H., additional, Baunin, C., additional, Railhac, J.-J., additional, and Sans, N., additional

Published
2011
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48. Radical Emulsion Polymerization of Alkylcyanoacrylates Initiated by the Redox System Dextran−Cerium(IV) under Acidic Aqueous Conditions

Author

Chauvierre, C., Labarre, D., Couvreur, P., and Vauthier, C.

Abstract

A radical emulsion polymerization of alkylcyanoacrylates (ACA) has been investigated to produce core−shell nanoparticles coated with polysaccharides. It was initiated by dextran on which a radical was created by reaction with cerium(IV) ions in an aqueous acidic medium. The redox radical polymerization developed in this study occurred much faster at pH 1 than the spontaneous anionic polymerization of ACA. It was applied to several ACA and has led to the formation of very stable suspensions of nanoparticles. The mean diameter of the nanoparticles depended on the monomer. Different analysis showed that the polymer forming the nanoparticles was an amphiphilic dextran based copolymer of poly(alkylcyanoacrylate). This copolymer exhibited surfactant properties. The size, morphology, and ζ potential of the nanoparticles have been determined as well as the mobility of the polysaccharide chains at the nanoparticle surface, which was investigated by electron paramagnetic resonance.

Published
2003

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