50 research outputs found

    Connaissances et pratiques ethnobotaniques en médecines traditionnelles vétérinaire et humaine au Bénin : similarité ou dissemblance ?

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    Objectif : Rechercher la similaritĂ© entre les usages liĂ©s aux plantes sollicitĂ©es en ethnomĂ©decines vĂ©tĂ©rinaire et humaine afin de contribuer Ă  la valorisation de ces connaissances endogĂšnes dans la zone cotonniĂšre du centre-BĂ©nin.MĂ©thodes et RĂ©sultats : Des enquĂȘtes ont Ă©tĂ© rĂ©alisĂ©es individuellement auprĂšs de 105 Ă©leveurs, agroĂ©leveurs et guĂ©risseurs traditionnels. Les paramĂštres de diversitĂ© floristique, ceux relatifs aux pratiques ethnobotaniques et les facteurs socioculturels dĂ©terminant la connaissance ethnobotanique sont utilisĂ©s pour les diverses comparaisons basĂ©es sur des tests de Khi Deux de Pearson et de deux proportions. La frĂ©quence (S) d’espĂšces ou d’usages communs a Ă©tĂ© calculĂ©e pour Ă©valuer le taux de similaritĂ© entre les deux types de mĂ©decine. Quatre-vingt douze (92) espĂšces de plantes impliquĂ©es dans la composition de 122 recettes ont Ă©tĂ© recensĂ©es pour les deux types de mĂ©decines. Globalement, la similaritĂ© est trĂšs grande entre les deux types de mĂ©decine en termes de plantes utilisĂ©es (86,69%) et grande en termes d’usages rapportĂ©s (65%).Conclusion et applications des rĂ©sultats : Certaines connaissances ethnovĂ©tĂ©rinaires proviendraient de la mĂ©decine humaine et vice-versa. Les plantes efficaces utilisĂ©es en ethnomĂ©decine vĂ©tĂ©rinaire pourraient ĂȘtre indiquĂ©es dans le traitement des mĂȘmes maladies chez l’homme en cas d’une similaritĂ© d’agents pathogĂšnes. Les Ă©tudes phytochimiques, pharmacologiques et cliniques devraient ĂȘtre envisagĂ©es pour la valorisation effective de ces plantes.Mots clĂ©s. EthnomĂ©decines vĂ©tĂ©rinaire et humaine, origine, similaritĂ©, Centre-BĂ©nin

    Steps towards the hyperfine splitting measurement of the muonic hydrogen ground state: pulsed muon beam and detection system characterization

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    The high precision measurement of the hyperfine splitting of the muonic-hydrogen atom ground state with pulsed and intense muon beam requires careful technological choices both in the construction of a gas target and of the detectors. In June 2014, the pressurized gas target of the FAMU experiment was exposed to the low energy pulsed muon beam at the RIKEN RAL muon facility. The objectives of the test were the characterization of the target, the hodoscope and the X-ray detectors. The apparatus consisted of a beam hodoscope and X-rays detectors made with high purity Germanium and Lanthanum Bromide crystals. In this paper the experimental setup is described and the results of the detector characterization are presented.Comment: 22 pages, 14 figures, published and open access on JINS

    Theory and design of Inx_{x}Ga1−x_{1-x}As1−y_{1-y}Biy_{y} mid-infrared semiconductor lasers: type-I quantum wells for emission beyond 3 ÎŒ\mum on InP substrates

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    We present a theoretical analysis and optimisation of the properties and performance of mid-infrared semiconductor lasers based on the dilute bismide alloy Inx_{x}Ga1−x_{1-x}As1−y_{1-y}Biy_{y}, grown on conventional (001) InP substrates. The ability to independently vary the epitaxial strain and emission wavelength in this quaternary alloy provides significant scope for band structure engineering. Our calculations demonstrate that structures based on compressively strained Inx_{x}Ga1−x_{1-x}As1−y_{1-y}Biy_{y} quantum wells (QWs) can readily achieve emission wavelengths in the 3 -- 5 ÎŒ\mum range, and that these QWs have large type-I band offsets. As such, these structures have the potential to overcome a number of limitations commonly associated with this application-rich but technologically challenging wavelength range. By considering structures having (i) fixed QW thickness and variable strain, and (ii) fixed strain and variable QW thickness, we quantify key trends in the properties and performance as functions of the alloy composition, structural properties, and emission wavelength, and on this basis identify routes towards the realisation of optimised devices for practical applications. Our analysis suggests that simple laser structures -- incorporating Inx_{x}Ga1−x_{1-x}As1−y_{1-y}Biy_{y} QWs and unstrained ternary In0.53_{0.53}Ga0.47_{0.47}As barriers -- which are compatible with established epitaxial growth, provide a route to realising InP-based mid-infrared diode lasers.Comment: Submitted versio

    Importance Du Couplage De L’inventaire Des Plantes MellifĂšres Et De L’analyse Pollinique Des Miels De La Saison Des Pluies En Zone Ouest Soudanienne Au Nord-BĂ©nin

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    The melliferous plants vary from one area to another according to biotic, climatic and ecological factors. This study was realized in the Sudanese region of Benin, in order to inventorize honey plants visited by the honeybee Apis mellifera adansonii Latreille. Pollen analysis of 34 samples of honey from three apiaries in the northwest of the country, combined with direct observations around each apiary within 1000 m radius were realized per month. In total 129 species were censised including 109 species inventorized on the field and 73 taxa identified through pollen analysis. Among these taxa, 43 are identified until species level. The contribution of pollen analysis to the knowledge of melliferous plants is 15.50%. The pollen analysis of honeys and visual inventory of honey plants field are two complementary methods of studying the honey flora

    A novel approach for assessing technical grade and quality of Lambda-cyhalothrin and acetamiprid in insecticides used in agricultural systems by HPLC technique in southern Benin

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    Open Access ArticleIn Benin, synthetic insecticides are the main pest control option used by farmers to protect and enhance their production. However, failures to control the target pests are often observed after application and may be related to agricultural practices or insecticide quality. The present work was designed to assess a rapid, simple, and reliable analytical method for detecting and quantifying the most commonly used insecticides (λ-cyhalothrin and acetamiprid) in Benin. The analytical standard technical grade separation was performed by gradient reversed-phase high-performance liquid chromatography on a C18 stationary-phase column. The mobile phase consisted of a mixture of acetonitrile/water using a gradient flow. The flow rates were 1 and 1.4 mL·min−1 for λ-cyhalothrin and acetamiprid, respectively. The analysis times were 15 and 20 min, with retention times of 2.35 and 7.94 min for λ-cyhalothrin and acetamiprid, respectively. Results reveal that most of the surveyed farmers were not educated (70% < Primary School Certificate) and were men (95%). Of the main insecticides applied by farmers, λ-cyhalothrin and acetamiprid were found to be the most technical-grade ones. Furthermore, the analysis of insecticides showed that the concentrations obtained in our study often differed from the ones mentioned on insecticide labels. The proposed method is useful for quantifying insecticides in various technical and commercial formulations with little interference from additives

    First measurement of the temperature dependence of muon transfer rate from muonic hydrogen atoms to oxygen

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    We report the first measurement of the temperature dependence of muon transfer rate from muonic hydrogen atoms to oxygen between 100 and 300 K. Data were obtained from the X-ray spectra of delayed events in a gaseous target, made of a H2/O2 mixture, exposed to a muon beam. This work sets constraints on theoretical models of muon transfer and is of fundamental importance for the measurement of the hyperfine splitting of muonic hydrogen ground state as proposed by the FAMU collaboration

    First measurement of the temperature dependence of muon transfer rate from muonic hydrogen atoms to oxygen

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    We report the first measurement of the temperature dependence of muon transfer rate from muonic hydrogen atoms to oxygen between 100 and 300 K. Data were obtained from the X-ray spectra of delayed events in a gaseous target, made of a H2/O2 mixture, exposed to a muon beam. This work sets constraints on theoretical models of muon transfer and is of fundamental importance for the measurement of the hyperfine splitting of muonic hydrogen ground state as proposed by the FAMU collaboration

    First FAMU observation of muon transfer from \u3bcp atoms to higher-Z elements

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    Abstract: The FAMU experiment aims to accurately measure the hyperfine splitting of the ground state of the muonic hydrogen atom. A measurement of the transfer rate of muons from hydrogen to heavier gases is necessary for this purpose. In June 2014, within a preliminary experiment, a pressurized gas-target was exposed to the pulsed low-energy muon beam at the RIKEN RAL muon facility (Rutherford Appleton Laboratory, U.K.). The main goal of the test was the characterization of both the noise induced by the pulsed beam and the X-ray detectors. The apparatus, to some extent rudimental, has served admirably to this task. Technical results have been published that prove the validity of the choices made and pave the way for the next steps. This paper presents the results of physical relevance of measurements of the muon transfer rate to carbon dioxide, oxygen, and argon from non-thermalized excited \u3bcp atoms. The analysis methodology and the approach to the systematics errors are useful for the subsequent study of the transfer rate as function of the kinetic energy of the \u3bcp currently under way

    FAMU: study of the energy dependent transfer rate \u39b \u3bcp \u2192 \u3bcO

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    The main goal of the FAMU experiment is the measurement of the hyperfine splitting (hfs) in the 1S state of muonic hydrogen \u394Ehfs (\u3bc - p)1S. The physical process behind this experiment is the following: \u3bcp are formed in a mixture of hydrogen and a higher-Z gas. When absorbing a photon at resonance-energy \u394Ehfs 48 0.182 eV, in subsequent collisions with the surrounding H 2 molecules, the \u3bcp is quickly de-excited and accelerated by ~ 2/3 of the excitation energy. The observable is the time distribution of the K-lines X-rays emitted from the \u3bcZ formed by muon transfer (\u3bcp) + Z \u2192 (\u3bcZ)* + p, a reaction whose rate depends on the \u3bcp kinetic energy. The maximal response, to the tuned laser wavelength, of the time distribution of X-ray from K-lines of the (\u3bcZ)* cascade indicate the resonance. During the preparatory phase of the FAMU experiment, several measurements have been performed both to validate the methodology and to prepare the best configuration of target and detectors for the spectroscopic measurement. We present here the crucial study of the energy dependence of the transfer rate from muonic hydrogen to oxygen (\u39b \u3bcp \u2192 \u3bc0 ), precisely measured for the first time

    The FAMU experiment at RIKEN-RAL to study the muon transfer rate from hydrogen to other gases

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    The aim of the FAMU (Fisica degli Atomi Muonici) experiment is to realize the first measurement of the hyperfine splitting (hfs) in the 1S state of muonic hydrogen _Ehf s 1S , by using the RIKEN-RAL intense pulsed muon beam and a high-energy mid-infrared tunable laser. This requires a detailed study of the muon transfer mechanism at different temperatures and hence at different epithermal states of the muonic system. The experimental setup involves a cryogenic pressurized gas target and a detection system based on silicon photomultipliers-fiber beam hodoscopes and high purity Germanium detectors and Cerium doped Lanthanium Bromide crystals, for X-rays detection at energies around 100 keV. Simulation, construction and detector performances of the FAMU apparatus at RAL are reported in this paper
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