77 research outputs found
Homologie d'Ă©volution de peuplements benthiques soumis aux Ă©pandages d'insecticides antisimulidiens
L'utilisation hebdomadaire d'insecticides pour lutter contre les Simulies modifie l`abondance des populations benthiques. Les variations ne sont ni de la même ampleur ni du même signe, selon l'insecticide (Abate, chlorphoxime, B.t.) et les taxons.Parmi les dizaines de rivières savanicoles traitées aux insecticides antisimulidiens, seules quelques unes font l'objet d'une surveillance de la faune non-cible. La problématique de ce travail est de savoir s'il est possible de généraliser à l'ensemble des rivières, les fluctuations d'abondance des populations observées sur une station de référence.Sur la station de référence, l'évolution de l'abondance des populations pour les trois insecticides étudiés est mesurée à l'aide du rapport : R/P = log APTi/log AVT, où log APTi est le logarithme de l'effectif moyen pour la période de traitement à l'insecticide i et où log AVT est le logarithme de l'effectif moyen avant traitement. Pour chaque taxon ainsi que pour la faune totale on obtient donc un rapport Abate, un rapport chlorphoxime et un rapport B.t.Les valeurs de ces rapports obtenus pour la station d'Entomokro, sont ensuite appliquées aux effectifs récoltés avant traitement sur trois autres stations. Les valeurs calculées sont comparées aux valeurs observées dans le cadre de la surveillance des rivières.Pour la faune totale, l'écart entre les valeurs calculées et les valeurs observées est très faible, r = 0,98.L'étude par taxon montre que la prédiction de ce modèle est excellente pour les Caenidae et les Hydropsychidae, bonne pour les Baetidae, les Chironomini, les Tricorythidae et les Orthocladiinae, médiocre pour les Tanypodinae et les Tanytarsini.The weekly utilization of insecticides sprayed by the Onchocerciasis Control Programme to control Simulium damnosum larvae modifies the abundance of the non target benthic populations. These insecticides (B.t., Abate and chlorphoxim) have neither the same toxicity nor the same selectivity for the principal taxa. In consequence, the long-term variations of the abundance of the populations are neither of the same importance nor of the same sign (some of them remain the same or decrease white others increase), according to the product and the taxa. In long term, these variations being mainly the consequence of direct toxicity but also take into account the duration of the life cycles as well as spatial and trophic competitions.Iin this study, only the saxicolous fauna is taken into account. If has been collected on rocks with the Surber sampler during the low water period (December to March).Among the ten Savannah rivers treated with antiblackfly insecticides, only few are the object of a non-target fauna monitoring. The abject of this work is to land out if it is possible to generalize to all the rivers, the variations in population abundance observed for an insecticide on a control station.In the reference station, the variation of population abundance for each of the insecticides is calculated by means of the ratio R/P = log APTi/log AVT, where log APTi is the logarithm of the average for the period treated with the i insecticide, and where log AVT is the logarithm of the average before treatment. For each taxa as well as for the total fauna, Abate, chlorphoxim and B.t. ratio were defined.The values of these ratio obtained for the Entomokro station on the Marahoué river in the Ivory Coast are then applied to the data collected before treatment on three rivers or stations (Amou-Oblo on the Amou river in Togo, Asubende on the Pru river in Toge and Danangoro on the Marahoué river in the Ivory coast). The calculated values are then compared to the values collected after treatment in the river monitoring programme.In the reference station the ratio of the populations collected before and after treatment are sometimes greater, sometimes lower than unit (when the ratio is greater than unit, it means that there is an increase of the abundance of populations during the processing period).The ratios are very close to the one for the B.t. which is the less toxic insecticide against the non target fauna, the greatest for the chlorphoxim which is the more toxic product and intermediate for Abate which has an intermediate toxicity. It appears that the more insecticides were estimated to be toxic in gutter tests, the more population abundance differ tram the reference ones.For the total fauna, differences between the values calculated and observed were very low (r 0,98). For the taxa, the prediction of this model is excellent for Caenidae and Hydropsychidae, good for Baetidae, Chironomini, Tricorythidae and Orthocladiinae, but mediocre for Tanypodinae and Tanylarsini. The authors submit some hypotheses to explain the bad adequation of the model for these two taxa; hypotheses based on taxonomic problems and niche releasing
La transdisciplinarite comme approche innovante de recherche action; le cas du projet syprobio
L’agriculture biologique et le commerce équitable en Afrique de l’Ouest centrés autour du coton, introduits depuis 1999, ont démontré un vrai potentiel d’augmenter les revenus et d'améliorer la sécurité alimentaire des petits productrices et producteurs. Actuellement, plus de 16'000 producteurs produisent le coton et d’autres cultures vivrières dans leurs systèmes de production en bio dans la sous-région. La diversification de ces cultures biologiques dans la rotation ou la combinaison de ces cultures avec celles d'arbres (agroforesterie) et de l’élevage visent à protéger la productivité en dépit des changements anticipés des conditions climatiques. A travers l'amélioration de la fertilité des sols et la diversification des systèmes de production, l'agriculture biologique a également un potentiel reconnu de contribuer à l'adaptation au changement climatique
Combustibles des ménages et modes d’utilisation à l’échelle du terroir de Vipalogo, en zone nord soudanienne du Burkina Faso
Au Burkina Faso, les besoins en combustibles énergétiques sont satisfaits surtout par le bois d’énergie. En milieu rural, le bois contribue pour 95% à la satisfaction des besoins énergétiques des ménages. Une meilleure connaissance de l’importance du bois et autres combustibles dans la satisfaction des besoins et des modes de consommation du combustible permettraient une meilleure gestion des formations végétales. Pour ce faire, à l’échelle du terroir de Vipalogo, 30 exploitations ont été retenues au hasard, et enquêtées sur les combustibles énergétiques utilisés. Des mesures de consommation de combustibles ont aussi été menées régulièrement à trois périodes de l’année, période froide et sèche, saison sèche et chaude et en saison pluvieuse. A Vipalogo, les ménages utilisent 1129,8 m3 de bois par an. La consommation maximale de bois par personne et par jour atteint 1,12 kg en période froide contre 0,90 kg en période chaude et 0,67 kg en période pluvieuse. En outre, il ressort qu’il y a des espèces préférentielles qui répondent à un certain nombre de critères en fonction de l’usage. Si pour tous les usages, l’aspect abondance est cité, pour le bois de feu, le critère qualité de combustion est le plus signalé. Les ressources ligneuses sont prélevées à 29,6% dans les champs de cases et de brousse et le reste dans les zones non cultivées, essentiellement les savanes. Les brousses et les jachères apportent la plus grande contribution à la satisfaction des besoins des populations en ressources ligneuses. Il ressort aussi un éloignement progressif des lieux de collecte qui dénote d’une raréfaction du produit.Mots clés : combustibles énergétiques, ménage, bois, résidus de récolte, champ, jachère
49 Left atrial strain is a powerful predictor of pulmonary artery hypertension in patients with severe aortic stenosis
Patterns of epidemiology and control of onchocerciasis in West Africa
This paper summarizes the work of the Onchocerciasis Control Programme (OCP) in West Africa, a programme which over a 22 year history has reduced the public health problems of blinding onchocerciasis in eleven countries of West Africa through vector control and, more recently, ivermectin distribution. The paper emphasizes the different approaches to control the programme has developed in the different parts of the programme area which have been determined by the epidemiology of the disease (savanna/forest form), the migratory characteristics of the vectors, intensity of the disease before commencement of treatment, the combined impact of vector control and ivermectin and the likelihood of infiltration of infective blackflies from outside the programme area. The programme has constantly monitored the impact of operations on the trends in prevalence, incidence, annual transmission potential, ocular morbidity and species of fly populations, and as a result, has identified areas where special interventions are required until the programme comes to an end in 2002. The paper illustrates the changes in intensity of infection as measured by community microfilarial load and annual transmission potential over the duration of the programme control activities. The paper also defines and justifies the control strategies in different areas and identifies areas for special intervention
Analysis of environmental conditions and management in a compost-bedded pack barn with tunnel ventilation
Received: January 5th, 2021 ; Accepted: March 27th, 2021 ; Published: April 16th, 2021 ; Correspondence: [email protected] housing system based on compost-bedded pack for dairy cows is spreading rapidly
in Brazil. Completely open buildings without curtains and simple roofs are usually provided.
However, in the last years some new completely closed barns have been realized. This study aims
to analyse one of these closed barns, located in the State of Minas Gerais. The two main sides of
the facility are provided with polyethylene curtains of blue colour and five deflectors. The barn
is equipped with an evaporative adiabatic cooling system, associated with the tunnel-style
ventilation, realized with exhaust fans, continuously operating 24 hours a day. 85 lactating
Holstein cows were housed in the barn during the trials carried out in the winter season 2019.
Microclimatic data were collected continuously. Air speed, illuminance and bedding temperature
were measured during the farm visits. Pack moisture was calculated. The results state the
importance of bedding management and climatic conditions inside the barn. It emerges that the
cows housed in this kind of closed barn, with forced ventilation, are in good thermal conditions,
which are fairly constant. The average illumination of the barn can be considered acceptable
(55.06 lx), even if some areas of the barn present values below the minimum ones reported in
literature. The bedding temperature varies between a maximum of 36.33 °C and a minimum of
25.44 °C with an average of 31.26 °C. The values of bedding moisture are between a maximum
of 64.36% and a minimum of 60.81% with an average of 62.48%
Decomposing multidimensional child poverty and its drivers in the Mouhoun region of Burkina Faso, West Africa
Analysis of environmental conditions and management in a compost-bedded pack barn with tunnel ventilation
Impact of ivermectin on onchocerciasis transmission: assessing the empirical evidence that repeated ivermectin mass treatments may lead to elimination/eradication in West-Africa
- …