Distribution and Contamination of Arsenic in Fish, Gastropods and Bivalves in the Aby and Tendo Lagoons in East of Ivory Coast

Lagoons are ecosystems for biodiversity and the livelihoods of coastal communities. The main objective of the study was to analyze the variability of arsenic concentrations in gastropods and bivalves in the Aby and Tendo lagoons, taking into account spatial, seasonal and hydrological variations. The study was carried out in four stages spread over two successive hydroclimatic cycles, including two seasons during the rainy season and two more during the dry season. The samples were taken in two areas of the Aby and Tendo lagoons. Arsenic levels were measured by ICP-MS. The results showed that mean arsenic concentrations in the muscles of organisms in Aby Lagoon ranged from 0.01 to 1.26 μg As/g, with a mean and median of 0.17 and 0.06 μg As/g, respectively. Fish had the highest levels of arsenic, followed by crustaceans, while molluscs and plants had lower and comparable concentrations of As. Arsenic concentrations in tilapia and jawbones varied significantly between sites and seasons, with higher concentrations at Tendo and during the rainy season. Arsenic concentrations in gastropods and bivalves were significantly higher than those of other species, with averages of 0.74 and 1.03 mg As/kg, respectively.

Reflected BSDEs Driven by Lévy Processes and Countable Brownian Motions

A new class of reflected backward stochastic differential equations (RBSDEs) driven by Teugels martingales associated with Lévy process and Countable Brownian Motions are investigated. Via approximation, the existence and uniqueness of solution to this kind of RBSDEs are obtained.

Ontogeny of Psychomotor and Sensory Functions in the Rat: Effects of Sexual Dimorphism

Background: We studied the development of eight (8) different psychomotor and sensory functions in male and female rats, from postnatal day 10 to 45, with the aim of determining whether the ontogenesis of these functions was subject to sexual dimorphism. Methods: Wistar rats bred according to standard conditions in our laboratories were put into reproduction. Ten days after whelping, male and female pups were identified and subjected to a battery of behavioral tests on postnatal days 10, 15, 20, 25, 30 and 45, to assess the development of the following psychomotor and sensory functions: Exploratory activity, locomotor activity, emotional defecation, hind paws lifting reflex latency, wire-grasping time, Latencies of execution of crawling along the wire and of leap onto the ground, nociception (tail flick) and body weight. Results: Only complex brain functions generated by cerebral cortex activities, i.e. exploratory activity and leap execution latency, do not undergo differential development sex-dependent. However, voluntary motor functions initiated in the motor cortex, and requiring high peripheral muscle performance such as crawling execution latency and wire-grasping time developed more rapidly in males than in females. Correlatively, body weight i.e. muscle mass index increased more speedily in males than in females. On the other hand, studies of automatic motor functions such as locomotor activity, and reflex motor functions i.e. hind paws lifting reflex latency and tail flick latency showed earlier development in females than in males. In addition, the study of emotional response, an emanation of limbic structures, showed prodigious development in females compared to males. Conclusion: Our studies have shown that there is a developmental sexual dimorphism of the central nervous system in the rat. Indeed, studies of automatic and reflex motor functions, whose activities are essentially linked to the spinal cord and brainstem, indicated that hindbrain areas develop more speedily in females than in males. Likewise, study of the emotional response emanating from diencephalic limbic structures, in particular the hypothalamus, showed a prodigious and early development in females compared to males. Taken together, our studies indicate that the vast majority of brain structures and functions reached maturation earlier in females than in males. Estrogen is the trigger hormone for early maturation of the female brain.

Recent Vegetation Cover Dynamics and Climatic Parameters Evolution Study in the Great Green Wall of Senegal

The drought recorded in 1970s and 1980s, particularly in the Sahara and Sahel region has greatly affected the population as well as the economies and the eco-systems of this area. In 2007, the African Union launched a Pan-African program, the Great Green Wall for the Sahara, the Sahel Initiative (GGWSSI) to reverse land degradation and desertification by planting a wall of trees stretching from Dakar to Djibouti. The objective is to improve food security, and support local people to adapt to climate change. This paper aims to evaluate the impacts of the reforestation program in Senegal, fifteen years after it was launched. This study uses a time series of satellite-derived vegetation cover and climatic parameters data to analyze the sustainability of these interventions. Change detection approaches were applied to identify and characterize the drives of the eventual changes. A comparative analysis of reforestation on climatic parameters was explored through the temporal analysis of the vegetation index over the periods 2000-2008 and 2009-2020. An increase in vegetation activity was noted through the NDVI at the interannual (+2% to +8%) and seasonal (+1.5% to 7% for the wet season and 1% to 4% for the dry season) scale and a positive and significant evolution is noted on the trace of the GGW. Also, the period 2009-2020 recorded an increase in rainfall of 2% to 8% of the average value 2000-2020 and 4% to 8% of the rainy season. Soil moisture is the climatic parameter that has increased the most, with an increase of 25% to 54% of the 2000-2020 average, i.e. between 20 mm and 70 mm more. This study shows a significant improvement in the relationship between NDVI and climate parameters after the different reforestation actions of the GGW.

Multiplex PCR for Identification and Detection of Cassava Mosaic Begomoviruses in Togo

Cassava mosaic disease (CMD) caused by Cassava Mosaic Begomoviruses (CMBs) is one of the most devastating crop diseases and a major constraint for cassava production. In order to ensure surveillance for epidemic prevention, low-cost diagnostic tools are appropriate for large-scale testing of cassava viruses. Multiplex PCR diagnosis is one approach that can reduce diagnostic costs and delays. A multiplex PCR approach was developed for simultaneous detection of African cassava mosaic virus (ACMV), East African Cassava Mosaic Virus and East African cassava mosaic Cameroon virus (EACMV/CM) in Togo CMD-infected cassava leaves. Three primers pairs were used to target their respective viruses in a single tube PCR. Multiplex PCR detected ACMV, EACMV and EACMV/CM in plant DNA extracts prepared from cassava leaves infected with CMB. The primers amplified 783 bp specific to ACMV, 650 bp specific to EACMV and 560 bp specific to EACMCV/CM in both uniplex and multiplex formats. Multiplex PCR is an excellent tool for the effective control of cassava diseases. .

Estimation of the Carbon Sequestration Dynamics of Senegal’s Great Green Wall Based on Land Cover over the Past Three Decades

The severe drought observed in the Sahel during 1970s, 1980s and 1990s has deeply affected the population as well as the economies and the eco-systems of this climatic area. The GGW Initiative spearheaded by Africa Union in 2007 proposed to combat the land degradation and desertification by planting a wall of trees stretching from Dakar to Djibouti. A reforestation was then conducted in the Senegal’s GGW since 2006 as part as other areas in the Sahel. This paper aims to evaluate the carbon sequestration dynamics in the sites of the Senegal’s GGW over the last three decades. The method consists firstly of analyzing the evolution of land cover and land use dynamics based on ESA-CCI LC satellite data. There is an improvement of the surface areas of tree and shrub savanna of 11.40% (Tessekere), 8.25% (Syer) and 2.70% (Loughere-Thioly). The regreening of the different localities and a positive dynamic observed is explained by the return to normal rainfall and to reforestation actions, agroforestry practices, better management of natural resources undertaken. However, some non-reforested sites showed an opposite trend despite of the normal rainfall. Secondly, the results on land mapping are used as a proxy for the assessment of carbon stocks. The dynamic observed in vegetation cover since the beginning of the reforestation made it possible to sequester 5.8 million tons of carbon representing respectively 2.31% of African GGW. This gain in stored carbon is equivalent to 21.2 million tons of CO2 captured in the atmosphere. Through this study, it appears that carbon storage becomes significant 8 to 10 years after the start of reforestation. An urbanization without respect for the environmental factors could be a danger for the climate (case of Ballou).

Total Indicative Dose Determination in Water from the North Riviera Well Field of SODECI in Abidjan, Cote d’Ivoire

The Uranium-238 (238U), Thorium-232 (232Th) families and Potassium-40 (40K) are of terrestrial origin and contribute generally to an individual’s external exposure through our presence in this environment. They also contribute to the internal exposure through the ingestion of products and beverages such as water that are close to the earth. The aim of this work is to determine the committed effective dose or Total Indicative Dose (TID) due to gamma radioactivity of the borehole water from the Nord Riviera (NR) well field operated by the Côte d’Ivoire Water Distribution Company (SODECI) for the supply of drinking water to part of the population of Abidjan. In addition, the populations, with their habits, could use these borehole waters directly as drinking water. To this end, water samples from the seven (07) functional boreholes were collected and analyzed on a gamma spectrometry chain, equipped with an HPGe detector in the laboratory of the Radiation Protection Institute (RPI) of the GHANA Atomic Energy Commission (GAEC). The results of the specific activities of 238U, 232Th and 40K obtained were transcribed into TID. As the natural radioactivity of the borehole water is high [1], the TIDs calculated from the activity results of the natural radionuclides238U, 232Th, and 40K vary for the seven boreholes from 0.150 to 0.166 mSv/yr with an average of 0.161 ± 0.034 mSv/yr. The TID of the control tower, where the borehole water is mixed and treated for household use, is equal to 0.136 ± 0.03 mSv/yr. The TIDs obtained are therefore all slightly greater than the WHO reference dose value of 0.1 mSv/yr. But all remain below the UNSCEAR reference dose of 0.29 mSv/yr.

Forced Electrocodeposition of Silica Particles into Nickel Matrix by Horizontal Impinging Jet Cell

The improvement of silica particle codeposition into a nickel electrodeposited composite coating (ECC) by a double face horizontal impinging jet cell (IJC) has been studied. The microstructure of coatings was examined by means of scanning electron microscopy performed in backscattered electron mode. The embedded particles distribution was shown to be the densest and the most uniform in laminar low flow mode and when the nozzle is at a distance of 5 mm close from the cathode. Excrescences observed on the composite surface are due to the wave-like flow of the jet on the cathode surface. The silica content of the nickel composite coatings was assessed by energy dispersive X-ray spectroscopy. The amount of particles embedded in the coating decreases with an increasing Reynolds number and as the nozzle-to-sample distance d becomes larger. A maximum rate of 4.43 wt% of silica has been successfully loaded at a distance d equal to 5 mm in the Ni-SiO2 composite coating.

Fighting Poor Quality Medicines: Development, Transfer and Validation of Generic HPLC Methods for Analyzing Two WHO Recommended Antimalarial Tablets

As serious but neglected public health problems, poor quality medicines, i.e. for antimalarial medicines, urged to be fought. One of the approaches is to consider the analytical chemistry and separative techniques. In this study, a generic liquid chromatographic method was firstly developed for the purpose of screening 8 antimalarial active ingredients, namely amodiaquine (AQ), piperaquine (PPQ), sulfalene (SL), pyrimethamine (PM), lumefantrine (LF), artesunate (AS), artemether (AM) and dihydroartemisinine (DHA) by applying DoE/DS optimization strategy. Since the method was not totally satisfying in terms of peak separation, further experiments were undergone applying the same development strategy while splitting the 8 ingredients into five groups. Excellent prediction was observed prior to correlation between retention times of predicted and observed separation conditions. Then, a successful geometric transfer was realized to reduce the analysis time focusing on the simultaneous quantification of two WHO’s recommended ACTs in anti-malarial fixed-dose combination (AM-LF and AS-AQ) in tablets. The optimal separation was achieved using an isocratic elution of methanol-ammonium formate buffer (pH 2.8;10 mM) (82.5:17.5, v/v) at 0.6 ml/min through a C18 column (100 mm × 3.5 mm, 3.5 μm) thermostated at 25℃. After a successful validation stage based on the total error approach, the method was applied to determine the content of AM/LF or AS/AQ in seven brands of antimalarial tablets currently marketed in West, Central and East Africa. Satisfying results were obtained compared to the claimed contents.

Elemental Composition of PM2.5 and PM10 in the Industrial Area of Yopougon, Abidjan, Côte d’Ivoire

This paper describes the evaluation of trace element composition of atmospheric aerosol particles (PM2.5 and PM10) and their influence on air quality in the largest industrial area of Abidjan city, C?te d’Ivoire. Multi-week sampling was conducted in an urban site (industrial area) in Abidjan from April 2018 to July 2019. The mean mass concentration was 48.83 ± 15.24 μg/m3 for PM2.5 and 77.34 ± 10.91 μg/m3 for PM10, with significant temporal variability. The average ratio of PM2.5/PM10 was 0.64 ± 0.21. The concentration of BC in PM2.5 and PM10 was respectively 52.32 ± 7.48 μg/m3 and 52.26 ± 12.07 μg/m3. Twenty-two elements: Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Rb, Sr, Zr and Pb were analysed by Energy Dispersive X-ray Fluorescence (EDXRF). Elemental composition data were modeled using principal component analysis (PCA) with varimax rotation to determine two (2) and four (4) dominant source categories contributing to PM2.5 and PM10 respectively. In the case of fine particles PM2.5, the possible sources were Industrial activities and non-exhaust emissions, exhaust emissions. The PM10 sources were industrial activities and non-exhaust emissions, industrial processes, mineral dust, and waste combustion.