50 research outputs found
Connaissances et pratiques ethnobotaniques en médecines traditionnelles vétérinaire et humaine au Bénin : similarité ou dissemblance ?
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) dâespĂšces ou dâusages 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 dâusages 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 lâhomme en cas dâune similaritĂ© dâagents 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
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 InGaAsBi mid-infrared semiconductor lasers: type-I quantum wells for emission beyond 3 m on InP substrates
We present a theoretical analysis and optimisation of the properties and
performance of mid-infrared semiconductor lasers based on the dilute bismide
alloy InGaAsBi, 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 InGaAsBi quantum wells (QWs)
can readily achieve emission wavelengths in the 3 -- 5 m 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
InGaAsBi QWs and unstrained ternary
InGaAs 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 Lâinventaire Des Plantes MellifĂšres Et De Lâanalyse Pollinique Des Miels De La Saison Des Pluies En Zone Ouest Soudanienne Au Nord-BĂ©nin
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
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·minâ1 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
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
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
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
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
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