Papers by Ibrahima Fania Camara
Pathogens
Background: The protocol study will focus on the seroprevalence of IgG antibodies to SARS-CoV-2 a... more Background: The protocol study will focus on the seroprevalence of IgG antibodies to SARS-CoV-2 achieved by vaccination and/or natural protection as well as the history, symptoms, and risk factors for SARS-CoV-2 in four primary health-care workers (PHCWs) and their household contacts in metropolitan France. Methods: Here, we propose a protocol for a nationwide survey to determine the seroprevalence of IgG antibodies to SARS-CoV-2 achieved by vaccination and/or natural protection in four PHCW populations (general practitioners, pediatricians, pharmacists and assistants, and dentists and assistants) and their household contacts. Participants will be included from June to July 2021 (Phase 1) among PHCW populations located throughout metropolitan France. They will be asked to provide a range of demographic and behavioral information since the first SARS-CoV-2 wave and a self-sampled dried blood spot. Phase 1 will involve also a questionnaire and serological study of PHCWs’ household con...
Advances in Intelligent Systems and Computing, 2018
This paper firstly examines the total factor productivity on Nanshan economic growth by Cobb–Doug... more This paper firstly examines the total factor productivity on Nanshan economic growth by Cobb–Douglas production function in the background of Chinese supply-side structural reform. Then, we attempt to apply stochastic frontier production function to decompose total factor productivity into technological progress and technical efficiency and calculate the contribution to economic growth. Finally, the results of the analysis are used to comprehensively evaluate the quality of economic growth in Nanshan.
Incident wave conditions and morphological beach response in the region of West and Central Afric... more Incident wave conditions and morphological beach response in the region of West and Central Africa are investigated using data collected with a regional network of permanent video cameras systems. Daily beach profiles were computed combining video shoreline detection at different tide levels and bathymetric estimate from wave celerity at three specific sites: Grand Popo (Benin), Mbour (Senegal) and Kribi (Cameroon). Results show that the low tide terrace of the intermediate-reflective beach of Grand Popo affects shoreline response at the event and seasonal time scales by modulating wave energy at the beach face. Based on this preliminary study and in the framework of a sustainable video station deployment, this paper highlights the potential of a video station network to address waves and coastal response on the time scales from hours to decade(s) in tropical coastal environments where data are lacking.
Atmosphere, 2020
This study investigates the physical processes controlling the mixed layer buoyancy using a regio... more This study investigates the physical processes controlling the mixed layer buoyancy using a regional configuration of an ocean general circulation model. Processes are quantified by using a linearized equation of state, a mixed-layer heat, and a salt budget. Model results correctly reproduce the observed seasonal near-surface density tendencies. The results indicate that the heat flux is located poleward of 10° of latitude, which is at least three times greater than the freshwater flux that mainly controls mixed layer buoyancy. During boreal spring-summer of each hemisphere, the freshwater flux partly compensates the heat flux in terms of buoyancy loss while, during the fall-winter, they act together. Under the seasonal march of the Inter-tropical Convergence Zone and in coastal areas affected by the river, the contribution of ocean processes on the upper density becomes important. Along the north Brazilian coast and the Gulf of Guinea, horizontal and vertical processes involving sa...
At-Tafkir, 2020
This article discusses the characteristics of teacher who teaches Islamic sciences in the perspec... more This article discusses the characteristics of teacher who teaches Islamic sciences in the perspective of the Nahdlatul Wathan educational tradition, comprehensively. On the other hand, this article is one form of response to the moral degradation of teachers that have recently been rife, especially in Indonesia. This article is the result of qualitative research with a literature approach. Primary data are the books of Tuan Guru Kiai Haji Muhammad Zainuddin Abdul Madjid (Sheikh), which include Wasiat Renungan Masa (Book), Batu Ngompal (Book), the struggle song of Nahdlatul Wathan, and the recording of Sheikh's speech during his lifetime. Secondary data consists of scientific journals and relevant research results, as well as Islamic education books, Sufism, tafsīr and hadīth. Data was collected offline and online, then analyzed by using the NVivo 12 Plus software. This study shows that nine characteristics must be possessed by religious teachers who teach in the Nahdlatul Wathan...
Internal Medicine Inside, 2019
The objective of this study was to describe the cardiac manifestations during systemic scleroderm... more The objective of this study was to describe the cardiac manifestations during systemic scleroderma in Conakry and the therapeutic management. Observation: 49-year-old female patient, admitted to the Medico-Surgical Emergency Department of Donka Hospital and University for chest pain, dry cough, osteo-articular pain, physical asthenia; evolution of symptoms for two weeks, no history of known cardiovascular disease and no cardiovascular risk factor. On physical examination, we have: TA=130/80 mmHg, heart rate at 110 beats/minute, height 1.78 cm, weight 65 kg (BMI: 20.56 kg/m 2). There was also a decrease in heart sounds, no rhythm disorder or deformation of the chest, no scar on the thorax, temperature at 37.6°C, axial deformation of the fingers of both hands with hypochromia, hard, localized at the level of small joints. Conclusion: Systemic scleroderma is an autoimmune disease that is more common in women than in men. His diagnosis is clinical, immunological and completed by the classification criteria. The functional or vital prognosis can be put into play especially in case of heart attack as was the case in our patient. Corticotherapy opens a window of hope despite the fact that treatment is difficult.
PLOS ONE, 2018
Insects such as locusts and grasshoppers can reduce the effectiveness of pathogens and parasites ... more Insects such as locusts and grasshoppers can reduce the effectiveness of pathogens and parasites by adopting different defense strategies. We investigated the behavioral thermopreference of Locusta migratoria manilensis (Meyen) (Orthoptera: Acrididae) induced by the fungus Beauveria bassiana, and the impact this behavior had on the fungal mycosis under laboratory conditions. By basking in higher temperature locations, infected nymphs elevated their thoracic temperature to 30-32.6˚C, which is higher than the optimum temperature (25˚C) for B. bassiana conidial germination and hyphal development. A minimum thermoregulation period of 3 h/ day increased survival of infected locusts by 43.34%. The therapeutic effect decreased when thermoregulation was delayed after initial infection. The fungus grew and overcame the locusts as soon as the thermoregulation was interrupted, indicating that thermoregulation helped the insects to cope with infection but did not completely rid them of the fungus. A significant enhancement in the number of haemocytes was observed in infected thermoregulating locusts, reaching levels that were even higher than those observed in the controls. In contrast, haemocyte concentration was severely reduced in infected insects that did not thermoregulate. In infected non-thermoregulating locusts, the reduction in haemocyte number was accompanied by an increase in fungal blastospore concentration that was obvious in the haemolymph by day four. In contrast, no circulating blastospores were found in the haemolymph of infected thermoregulating locusts three days post-inoculation. We also examined the phagocytic activity of infected insects in vivo by using fluorescein isothiocyanate (FITC)-labelled silica beads. The proportion of beads that was engulfed by haemocytes in infected, thermoregulating insects was similar to that in the controls throughout the experiment, whereas the rate of phagocytosis in infected, non-thermoregulating insects progressively decreased after infection. These findings demonstrated that behavioural thermoregulation can adversely affect B. bassiana mycosis in infected L. migratoria manilensis, thereby limiting the development of lethal entomopathogenic fungi in locusts. This is apparently accomplished through an increase in the levels of haemocytes, leading to greater phagocytic activity under certain environmental conditions.
Journal of economic entomology, Jan 30, 2018
Aphids are important agricultural pests because of their feeding and, for many species, their abi... more Aphids are important agricultural pests because of their feeding and, for many species, their ability to transmit plant pathogenic viruses. Orius sauteri (Poppius) (Hemiptera: Anthocoridae) is an important predator in northern China of many aphid species, including Aphis craccivora (Koch) (Hemiptera: Aphididae). We measured the functional response and intraspecific competition of O. sauteri under different densities of A. craccivora at several constant temperatures. Predation of O. sauteri on A. craccivora conformed to Holling's type II functional response at all temperatures tested. The predation capability of O. sauteri showed a significant correlation with temperature. The predation capacity of O. sauteri was highest at 25°C, at which temperature we found the highest instantaneous attack rate (a = 0.8711), the theoretical maximum number of aphids captured (181.36), and the shortest handling time (Th = 0.0055). Predation by O. sauteri increased progressively with temperature f...
Pest management science, Jan 24, 2018
Paranosema locustae Canning, 1953 (Microsporidia) provides effective control of grasshoppers. Hor... more Paranosema locustae Canning, 1953 (Microsporidia) provides effective control of grasshoppers. Horizontal transmission of P. locustae is known to occur, and evidence for the mechanism of this transmission via predatory natural enemies has been found. We conducted a 3-year laboratory and field study to assess the potential impact of feces from both grasshoppers Locusta migratoria L. and their natural enemies on the persistence of P. locustae. We found that P. locustae persisted among grasshopper populations in treated areas and in adjacent untreated areas for up to 2 years, and the density of grasshoppers decreased in both areas. We showed that healthy grasshoppers could be infected by eating food contaminated by feces from their natural enemies. Grasshopper predators retained a large number of spores acquired from eating grasshoppers infected with P. locustae. Spores in the feces of the main natural enemy, the beetle Pterostichus gebleri Dejean 1828, in the treated area showed clear ...
Journal of Physics: Condensed Matter, 2017
The resonant eigenmodes of a nitrogen-implanted iron α'-FeN characterized by weak stripe domains ... more The resonant eigenmodes of a nitrogen-implanted iron α'-FeN characterized by weak stripe domains are investigated by Brillouin light scattering and broadband ferromagnetic resonance experiments, assisted by micromagnetic simulations. The spectrum of the dynamic eigenmodes in the presence of the weak stripes is very rich and two different families of modes can be selectively detected using different techniques or different experimental configurations. Attention is paid to the evolution of the mode frequencies and spatial profiles under the application of an external magnetic field, of variable intensity, in the direction parallel or transverse to the stripes. The different evolution of the modes with the external magnetic field is accompanied by a distinctive spatial localization in specific regions, such as the closure domains at the surface of the stripes and the bulk domains localized in the inner part of the stripes. The complementarity of BLS and FMR techniques, based on different selection rules, is found to be a fruitful tool for the study of the wealth of localized magnetic excitations generally found in nanostructures.
Journal of Applied Crystallography, 2016
Surface acoustic waves of micrometre wavelength travelling on a monocrystal give diffraction sate... more Surface acoustic waves of micrometre wavelength travelling on a monocrystal give diffraction satellites around each Bragg peak in an X-ray diffraction diagram. By using a four-crystal monochromator, a secondary two-crystal analyser and masks reducing the footprint to the part of the crystal containing the acoustic modulation, it is possible to observe these satellites on a GaAs (001) surface using a laboratory diffractometer. The finite extension of the satellite diffraction rods and of the crystal truncation rod perpendicular to the surface leads to geometrical correction factors when convoluted with the instrumental resolution function, which had previously been ignored. The calculation of these geometrical correction factors in the framework of the kinematic approximation allows the determination of the surface acoustic wave amplitude, and the study of its attenuation and its dependence on radiofrequency power and duty cycle. The ability to perform such determinations with a labo...
Environmental science and pollution research international, Jan 11, 2016
Ostrinia furnacalis (Guenée) and Helicoverpa armigera (Hübner) are the most important pests of ma... more Ostrinia furnacalis (Guenée) and Helicoverpa armigera (Hübner) are the most important pests of maize in China. A laboratory study and a 2-year field study on the efficacy of transgenic maize expressing the Cry1Ac protein BT38 against O. furnacalis and H. armigera were performed. We found that the husks, kernels, and silks of BT38 showed significant efficacy against larvae of O. furnacalis and H. armigera. In the field, when neonate larvae of O. furnacalis and H. armigera were on plants at different growth stages and when levels of leaf-damage or number of damaged silks were used to score efficacy, we found that BT38 showed significant insecticidal efficacy against O. furnacalis and H. armigera, but the non-Bt maize did not show significant efficacy against either pest. These results suggest that the insecticidal efficacy of Bt maize expressing the Cry1Ac protein could be useful in the integrated pest management of these key maize pests.
Molecules (Basel, Switzerland), Jan 21, 2015
Based on MS and NMR data and bioassay-guided tracing, three insecticidal alkaloids I, II and III ... more Based on MS and NMR data and bioassay-guided tracing, three insecticidal alkaloids I, II and III from Cynanchum mongolicum were identified to be antofine N-oxide, antofine and tylophorine. Alkaloid I was more toxic than alkaloids II and III, but they were less active against Spodoptera litura than total alkaloids. The contact toxicity from these alkaloids against the aphid Lipaphis erysimi was significant, as the 24 h-LC50 values of alkaloids I, II, III and total alkaloids were 292.48, 367.21, 487.791 and 163.52 mg/L, respectively. The development disruption of S. litura larvae was tested, the pupation and emergence rates of S. litura decreased and the acute mortality of S. litura increased significantly by day 3 after being injected in their body cavity with 10-40 mg/L of total alkaloid. The ecdysone titer of treated S. litura larvae and prepupae declined with increasing alkaloid concentration. The alkaloids of Cynanchum mongolicum are potential insect growth inhibitors.
Journal of Geophysical Research: Oceans, 2013
We investigate the causes of the seasonal cycle of the near-surface salinity using a mixed-layer ... more We investigate the causes of the seasonal cycle of the near-surface salinity using a mixed-layer salinity model and a combination of satellite products, atmospheric reanalyses, and in situ observations for the period 2000-2008, in the tropical Atlantic Ocean. We find that the balance differs from one region to another. In the western tropical Atlantic, it is controlled by horizontal advection from March to November and by freshwater flux and entrainment for the rest of the year. In the central tropical Atlantic, it is mainly due to the strong contribution of precipitation in agreement with previous results. In the northeastern tropical Atlantic, all terms contribute to the mixed layer salinity between December and March; during the rest of the year, precipitation and zonal advection mainly control the balance. In the Gulf of Guinea, it is driven by freshwater flux from October to February; from March to July, it is controlled by horizontal advection and entrainment; from August to September, mixed-layer salinity variability is weak. Finally, in the Congo region, it is driven by freshwater flux (precipitation and runoff from Congo River) from September to December, by horizontal advection during January to March, and by vertical entrainment during the rest of the year (April to August). There are some discrepancies between observed and modeled salinity tendencies. Some of them are due to our model formulation, which does not explicitly account for the effect of vertical diffusion. Uncertainties of observation products, which force the model, are also sources of errors.
Journal of Geophysical Research: Oceans, 2015
The physical processes controlling the mixed layer salinity (MLS) seasonal budget in the tropical... more The physical processes controlling the mixed layer salinity (MLS) seasonal budget in the tropical Atlantic Ocean are investigated using a regional configuration of an ocean general circulation model. The analysis reveals that the MLS cycle is generally weak in comparison of individual physical processes entering in the budget because of strong compensation. In evaporative regions, around the surface salinity maxima, the ocean acts to freshen the mixed layer against the action of evaporation. Poleward of the southern SSS maxima, the freshening is ensured by geostrophic advection, the vertical salinity diffusion and, during winter, a dominant contribution of the convective entrainment. On the equatorward flanks of the SSS maxima, Ekman transport mainly contributes to supply freshwater from ITCZ regions while vertical salinity diffusion adds on the effect of evaporation. All these terms are phase locked through the effect of the wind. Under the seasonal march of the ITCZ and in coastal areas affected by river (78S:158N), the upper ocean freshening by precipitations and/or runoff is attenuated by vertical salinity diffusion. In the eastern equatorial regions, seasonal cycle of wind forced surface currents advect freshwaters, which are mixed with subsurface saline water because of the strong vertical turbulent diffusion. In all these regions, the vertical diffusion presents an important contribution to the MLS budget by providing, in general, an upwelling flux of salinity. It is generally due to vertical salinity gradient and mixing due to winds. Furthermore, in the equator where the vertical shear, associated to surface horizontal currents, is developed, the diffusion depends also on the sheared flow stability.
Médecine et Maladies Infectieuses, 2003
Objectifs.-Étudier la prévalence des germes responsables de la méningite purulente chez l'enfant ... more Objectifs.-Étudier la prévalence des germes responsables de la méningite purulente chez l'enfant au Sénégal et leur sensibilité aux antibiotiques. Méthodes.-À partir d'un travail rétrospectif portant sur une période de 6 ans (du 1 er janvier 1995 au 31 décembre 2000), nous avons étudié les aspects cliniques épidémiologiques et thérapeutiques des cas de méningite purulente, hospitalisés à l'hôpital d'enfants Albert-Royer de Dakar. Ont été concernés par l'étude, tous les enfants âgés de 0 à 15 ans chez qui le diagnostic de méningite purulente a été confirmé par le laboratoire. Résultats.-Il y a eu 1095 méningites purulentes pour 22 162 hospitalisations (soit 4,9 %). L'affection sévit toute l'année avec une recrudescence de janvier à mai. L'âge moyen des patients était de 37,8 mois et le pic de fréquence se situait entre 1 et 6 mois. La bactériologie était positive dans 594 cas (54,2 %). Haemophilus influenzae b, Neisseria meningitidis et Streptococcus pneumoniae sont les principaux germes. L'activité des antibiotiques courants est excellente sur ces germes. L'évolution globale a donné un taux de guérison de 71,9 % et une létalité de 16,3 %. Commentaires.-H. influenzae b, principal agent de méningite purulente dans notre série, est responsable d'une importante morbidité et d'une mortalité élevée dans des pays comme le Sénégal où la vaccination contre ces germes n'est pas systématique. De ce fait, nous recommandons l'introduction dans les plus brefs délais, du vaccin contre H. influenzae b, dans le programme élargi de vaccination au Sénégal.
Advanced Materials Research, 2012
In practical situations, machines might not be available during certain time of period due to det... more In practical situations, machines might not be available during certain time of period due to deterministic or stochastic causes in many production systems. And, processing times are always not exact as they have been predicted. In this paper, we attempted to study the three machines flow shop scheduling problem in which probabilities are associated with processing times of jobs involving transportation time, machine breakdown interval and weights of jobs. A simple heuristic approach is proposed to find optimal or near optimal sequence minimizing the weighted mean production flow time. A numerical example has been provided to illustrate and clarify the proposed algorithm.
Background: On January 30, 2020, the World Health Organization designated the outbreak as a Publi... more Background: On January 30, 2020, the World Health Organization designated the outbreak as a Public Health Emergency of International Scope (USPPI). Underdeveloped countries, such as the Republic of Guinea, where the health system has been severely impacted by the Ebola virus epidemic between 2013 and 2014, will therefore find it difficult to respond effectively to the predicted epidemic. The purpose of this study was to assess the knowledge, attitudes and practices of medical personnel on the prevention of Covid-2019.Methods:This was a cross-sectional study with an analytical aim carried out from 1st to 29th February 2020 among front-line health workers in the health structures of the city of Conakry. Data were collected using the Kobocollect application by administration of a standardized questionnaire. The knowledge and attitude score was categorized in 2: Good if ≥ at the average score and bad if < 50%. Logistic regression models were conducted to identify factors associated w...
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Papers by Ibrahima Fania Camara