753 research outputs found
Stratégie de reproduction du carangidae Trachinotus teraia cuvier, 1832 dans la lagune ebrié (Côte d’Ivoire)
La reproduction de Trachinotus teraia a été étudiée dans la lagune Ebrié au cours de campagnes mensuelles pendant deux années consécutives (février 2004 à janvier 2006). Cette étude se situe dans le cadre d’acquisition de connaissances sur la biologie de Trachinotus teraia en vue d’évaluer son potentiel aquacole. Au total, 1806 spécimens dont 739 mâles, 746 femelles et 321 juvéniles ont été capturés à l’aide de filets maillants (mailles : 10, 14, 20, 25, 30, 35, 40, 50, 80 et 100 mm) et examinés. En ce qui concerne les paramètres déterminés, le sex-ratioest 1 : 1. La taille de première maturité sexuelle (LF50) est atteinte à 199 mm et 212 mm respectivement chez les mâles et les femelles. Le plus petit individu mâle mature capturé mesure 154 mm (LF) et pèse 86,85 g tandis que la plus petite femelle mature capturée mesure 170 mm (LF) et pèse 118,24 g. Les variations mensuelles des indices gonadosomatique(IGS), hépato-somatique (IHS), du facteur de condition (K) et des stades de maturité indiquent deux périodes de reproduction. La longue période de ponte se situe de février à avril tandis que la courte période de ponteintervient de septembre à octobre. Les réserves hépatiques semblent être mobilisées pour assurer le coût énergique de la reproduction. La fécondité absolue varie entre 15 053 et 2 058 907 ovocytes pour des femelles de tailles comprise entre 260 et 582 mm. Les moyennes des diamètres ovocytaires de ces femelles sont deReproductive biology of Trachinotus teraia was studied in the Ebrié lagoon during two years (from February 2004 to January 2006) by monthly sampling using gill nets with stretched mesh sizes 10, 14, 20, 25, 30, 35, 40, 50, 80, and 100 mm). Basic biological information was collected to describe some aspects of reproductive biology of T. teraia for use in aquaculture programmes. A total of 1806 specimens were examined (739 males, 746 females and 321 juveniles. The sex ratio was 1:1. The size at first sexual maturity (LF50) is reached at 199 mm and 212 mm respectively for the males and females. The smallest mature male was 154 mm (LF) and weighed 86.85 g while in female, this maturity occurred at 170 mm and 118.24 g. The monthly variations of the gonado-somatic index (GSI) and hepato-somatic index (HSI), the condition factor (K) and maturation stages indicated two periods of reproduction. The long period and the short period were respectively from February to April and from September to October. The hepatic reserves seem to be mobilized to ensure the energetic cost of the reproduction. The absolute fecundity was ranged from 15 053 to 2 058 907 oocytes for females of 260 and 582 mm (FL). The averages of the oocytes diameters ranged between 449.53 ± 152.49 μm and 393.29±126,85 μm, respectively for the large and the short periods of reproduction.Mots clés : Carangidae, Trachinotus teraia, reproduction, sex-ratio, fécondité, Côte d’Ivoire.
Biological nitrogen fixation in Crotalaria species estimated using the 15N isotope dilution method
A greenhouse experiment was conducted to measure nitrogen fixation in three Crotalaria species : C. ochroleuca, C. perrottetii and C. retusa growing in Senegal by using 15N direct isotope dilution technique. Two non-fixing plants, Senna obtusifolia and Senna occidentalis served as reference plants. The amount of nitrogen fixed two months after planting was obtained using the average of the two reference plants. The atom % 15N excess in the Crotalaria species was significantly lower than that of the reference plants, indicating that significant nitrogen fixation occurred in the three plants. Significant differences were observed between the Crotalaria species; C. ochroleuca yielded more dry matter weight and total nitrogen than did C. perrottetti and C. retusa. The % nitrogen derived from atmosphere (%Ndfa) in leaves and stems was also higher in C. ochroleuca. There was no significant difference in %Ndfa in the whole plant between the three Crotalaria species (47% to 53%). In contrast, interspecific variability was observed based on the %Ndfa. C. ochroleuca significantly exhibited the higher amount of total nitrogen fixed, equivalent to 83 kg of nitrogen fixed per hectare. Based on these data, it was concluded that C. ochroleuca could be used in multiple cropping systems in Senegal for making more nitrogen available to other plants.
(African Journal of Biotechnology: 2002 1(1): 17-22
A sensitivity study on the role of the swamps of southern Sudan in the summer climate of North Africa using a regional climate model
We used the regional climate model RegCM3 to investigate the role of the swamps of southern Sudan in affecting the climate of the surrounding region. Towards this end, we first assessed the performance of a high resolution version of the model over northern Africa. RegCM3 shows a good skill in simulating the climatology of rainfall and temperature patterns as well as the related circulation features during the summer season, outperforming previous coarser resolution applications of the model over this region. Sensitivity experiments reveal that, relative to bare soil conditions, the swamps act to locally modify the surface energy budget primarily through an increase of surface latent heat flux. Existence of the swamps leads to lower ground temperature (up to 2 °C), a larger north–south temperature gradient, and increased local rainfall (up to 40 %). Of particular importance is the impact on rainfall in the surrounding regions. The swamps have almost no impact on the rainfall over the source region of the Nile in Ethiopia or in the Sahel region; however, they favor wetter conditions over central Sudan (up to 15 %) in comparison to the bare desert soil conditions.Abdus Salam International Centre for Theoretical Physics (Earth System Physics)International Atomic Energy AgencySTEP progra
Facteurs Explicatifs de la Pratique Contraceptive Moderne des Femmes Fréquentant les Formations Sanitaires du District de Youwarou au Mali
Objectif : Mettre en exergue les déterminants de la pratique contraceptive moderne des femmes fréquentant les centres de santé du district de Youwarou au Mali. L’étude part du constat que la situation sanitaire est non satisfaisante avec un faible taux de fréquentation des centres de santé qui est de 15 %, exacerbée par la crise sécuritaire déclenchée en 2012. Ainsi, le taux d’utilisation des méthodes contraceptives modernes est également très faible soit 1,07%. En effet, l’utilisation de la contraception moderne selon la cinquième Enquête Démographique et de Santé du Mali (EDSM-5) est de 9,6% au niveau national et de 2,7% dans la région de Mopti. Méthode : Etude transversale quantitative dont l’enquête fut réalisée du 1er mai au 30 juin 2015, et a porté sur 200 femmes âgées de 15-49 ans fréquentant les 07 centres de santé dans le district de Youwarou. Les données collectées par un questionnaire ont été vérifiées, compilées à l’aide du logiciel le Sphinx Plus² version 4.5, puis transférées sur le logiciel stata 10 pour l’analyse statistique. Pour l’analyse des données, nous avons eu recours à deux méthodes dans ce travail : la méthode d’analyse descriptive (analyse bivariée) et la méthode d’analyse explicative (analyse multivariée). Résultats : L’étude montrent que la prévalence contraceptive moderne est de 8,8%. Les femmes de centre de Guidio-sare utilisent les contraceptives modernes plus que leurs consoeurs du district. Enfin les déterminants de la pratique contraceptive sont notamment l’ethnie, l’âge et le statut matrimonial de la femme. Conclusion : A la lumière de cette étude, nous suggérons qu’un accent particulier doit être mis sur les déterminants révélés afin de promouvoir les méthodes contraceptives modernes.
Objective: Highlight the determinants of modern contraceptive practice among women attending health centers in the Youwarou health district of Mali. The study was carried out based on the observation that the health situation is unsatisfactory with a low utilization rate of health centers is 15%, exacerbated by the security crisis triggered in 2012. Thus, the rate of use of modern contraceptive methods is also very low is 1.07%. Indeed, the use of modern contraception according to the fifth Demographic and Health Survey of Mali (EDSM-5) is 9.6% at the national level and 2.7% in the Mopti region. Methods: A quantitative cross-sectional study was carried out from May 1th to June 30th 2015, and covered 200 women aged 15-49 attending the 07 health centers in the district of Youwarou. The data collected by a questionnaire was verified, compiled using the software Sphinx Plus² version 4.5, and then transferred to the Stata 10 software for statistical analysis. For data analysis, two methods were used in this work: the descriptive analysis method (bivariate analysis) and the explanatory analysis method (multivariate analysis). Results: The study shows that modern contraceptive prevalence is 8.8%. women of Guidio-sare Center use modern contraceptives more than their sisters of district. Finally, the determinants of contraceptive practice include the ethnicity, age and marital status of women. Conclusion: In the light of this study, we suggest that emphasis should be placed on the identified determinants in order to promote modern contraceptive methods
Complexes soufrés du Mercure (II) et du Plomb (II) pour l’optique non linéaire
Date du colloque : 02/2011</p
Consistency of projected drought over the Sahel with changes in the monsoon circulation and extremes in a regional climate model projections
As a step toward an increased understanding of climate change over West Africa, in this paper we analyze the relationship between rainfall changes and monsoon dynamics in high-resolution regional climate model experiments performed using the Regional Climate Model (RegCM3). Multidecadal simulations are carried out for present-day and future climate conditions under increased greenhouse gas forcing driven by the global climate model European Center/Hamburg 5 (ECHAM5). Compared to the present day, the future scenario simulation produces drier conditions over the Sahel and wetter conditions over orographic areas. The Sahel drying is accompanied by a weaker monsoon flow, a southward migration and strengthening of the African Easterly Jet, a weakening of the Tropical Easterly Jet, a decrease of the deep core of ascent between the jets, and reduced African Easterly Wave activity. These circulation changes are characteristics of dry periods over the Sahel and are similar to the conditions found in the late twentieth century observed drought over the region. Changes in extreme events suggest that the drier conditions over the Sahel are associated with more frequent occurrences of drought periods. The projected drought over the Sahel is thus physically consistent with changes in the monsoon circulation and the extreme indices (maximum dry spell length and 5 day precipitation)
Implementation of active management of the third period of childbirth for the prevention of immediate post-partum bleeding in four regional maternity hospitals of Conakry, Guinea
Background: The objective of this study was to determine the frequency, skills level of health care service providers; to identify complications and difficulties related to the implementation of AMTPC/GATPA.Methods: It was about prospective study, descriptive of 6 months (1st March to 31st August 2014) carried out in the maternity hospitals of Faranah, Kindia, Mamou and Nzérékoré. It concerned the parturient women who had recently given birth and the personnel that carried out AMTPC/GATPA in these hospitals.Results: During the study period of 1,254 out of 1,305 births had benefited of AMTPC/GATPA, a frequency of 96.1%. The midwives were the most represented personnel in the implementation of GATPA (44.1%). In 46.4% of the cases, the health care service providers acquired this competence from the initial training. The release was obtained in the first trial in 64.9% cases. The duration of implementation of GATPA was less than 5 minutes in 72.6% cases. The different stages were respected in 91.5% cases. Complications were dominated by retention of placental fragments (10.2%). Lack of oxytocin was the main difficulty (36.6%).Conclusions: The sustainability of this achievement would depend on the systematic and correct implementation of AMTPC/GATPA at all childbirth attendants and the effective management of oxytocin
‘We Need to Deploy Them Very Thoughtfully and Carefully’: Perceptions of Analytical Treatment Interruptions in HIV Cure Research in the United States – A Qualitative Inquiry
Strategies to control HIV in the absence of antiretroviral therapy are needed to cure HIV. However, such strategies will require analytical treatment interruptions (ATIs) to determine their efficacy. We investigated how U.S. stakeholders involved in HIV cure research perceive ATIs. We conducted 36 in-depth interviews with three groups of stakeholders: 12 people living with HIV, 11 clinician-researchers, and 13 policy-makers/bioethicists. Qualitative data revealed several themes. First, there was little consensus on when ATIs would be ethically warranted. Second, the most frequent perceived hypothetical motivators for participating in research on ATIs were advancing science and contributing to society. Third, risks related to viral rebound were the most prevalent concerns related to ATIs. Stakeholders suggested ways to minimize the risks of ATIs in HIV cure research. Increased cooperation between scientists and local communities may be useful for minimizing risk. Further ethics research is necessary
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