Multiple Linear Regression (MLR) Model: A Tool for Water Quality Interpretation

The lack of standard water analysis equipment as well as inadequate trained personnel especially in the developing countries has discouraged many researchers in such countries to execute water quality researches. Hence, this paper presents developed mathematical relationship among some physicochemical parameters in order to aid the determination of the concentrations of certain parameters with the use of minimal equipment. This was achieved by weekly analyzing 7 physicochemical parameters of two sources of potable water (tap water and borehole water) stored in different containers for a period of 6 weeks using standard methods. The storage containers used were black plastic tank, blue plastic tank, green plastic tank, coated steel metal tank, uncoated steel metal tank and clay pot. The parameters examined were turbidity, electrical conductivity (EC), pH, alkalinity, chloride ion (Cl-), dissolved oxygen (DO) and total hardness. Results showed that the relationship between electrical conductivity (EC), alkalinity (Alk), total hardness (TH) and chloride ion (Cl-) is given as; EC = -224.8066493 + 6.244028022(Alk) + 0.28204735(TH) + 0.000518108(Cl-). A programing language was written on the models using Visual Basic.Net (VB.Net) version 2018. Keywords: Water, Physicochemical, Parameters, Function, Equation

Dynamique de l’occupation du sol dans le Parc National du W et sa périphérie au nord-ouest du Bénin

La dynamique spatio-temporelle de l’occupation du sol et les facteurs de dégradation ont été analysés à partir des images Landsat de 1972, de 1990 et de 2008, de la télédétection et d’un système d’information géographique (SIG), dans le Parc National du W et sa périphérie dans le Nord-Ouest du Bénin. L’objectif de la présente étude est d’une part d’analyser la dynamique de l’occupation du sol entre 1972 et 2008, et d’autre part, de déterminer les facteurs de dégradation du couvert végétal. Des enquêtes socioéconomiques ont été réalisées dans les villages riverains du Parc National du W. La classification supervisée par maximum de vraisemblance a été appliquée. Deux matrices de transition ont permis de mettre en évidence les conversions subies par les différentes unités d’occupation du sol. Les formations forestières ont régressé de 22,70% à 17,00% entre 1972 et 2008. Les forêts galeries dégradées quasi inexistantes en 1972 se sont reconstituées à partir de 1990 et sont passées de 0,60% à 2,85% en 2008. Quant aux forêts denses ainsi que les forêts claires et savanes boisées, elles ont subi une régression en terme de superficie (0,23% en 1972 à 0,09% en 2008 et de 17,90% à 12,91% respectivement). Par contre, les savanes arborées et arbustives ont connu une légère diminution (73% en 1972 à 66,65% en 2008) tandis que les mosaïques de champs et jachères ont connu une augmentation de leur superficie (1,38% en 1972 à 13,97% en 2008), soit plus de 10 fois leur superficie initiale de 1972. La démographie, l’agriculture et le surpâturage sont les trois principaux facteurs de dégradation du Parc National du W et de sa périphérie.Mots clés : Télédétection, SIG, dynamique, matrice de transition, Parc National du W

Degree of Integrated Water Resources Management Implementation in Context of Climate Change in a Watershed: Case of Oueme Basin, Benin (West Africa)

This study is based on the hypothesis that the implementation of Integrated Water Resources Management (IWRM) tools in the Oueme watershed has not led to a systematic improvement in the degree of IWRM implementation in the Oueme Valley in Benin. Methodologically, data were collected through a semi-structured survey of stakeholder families in the study area using snowball sampling. The tool used was the form developed by the United Nations to collect data to assess the level of IWRM implementation. The four (4) assessment criteria, each covering a key component of IWRM, are the enabling environment, institutions and participation, management tools and financing. The results obtained per criteria according to the stepwise methodology adopted reveal on average a degree of implementation of 40 on a scale of 0 to 100 in the Oueme basin. This value varies according to the geographical area and the factors considered. This study, which is a decision-making tool, provides a guide for governments to monitor the progress of integrated water resources management in their territory

Effects of acute exposure to cotton insecticide thalis 112 EC (emamectin benzoate 48 g.l-1 and acetamiprid 64 g.l-1) in African catfish Clarias gariepinus embryos

Thalis 112 EC, a binary insecticide based on Emamectin benzoate (48 g.L-1) and Acetamiprid (64 g.L-1), is widely used in agriculture in Benin, to control cotton pests including Helicoverpa armigera. In order to assess the impact of acute concentrations of this binary on the development of  eggs/embryos of the African catfish Clarias gariepinus, an experiment was conducted in the laboratory. The fertilized eggs of C. gariepinus (n 100)  were exposed to six concentrations of Thalis (T0: 0.0; T1: 10.0; T2: 60.0; T3: 110.0; T4: 160.0 and T5: 210.0 ppm), each in three replicates. The  arithmetic method of Karber was used to calculate LC50 values. The 24h-LC50 and 48h-LC50 values of Thalis for eggs/embryos were 124.09 and  117.58 ppm, respectively. High Thalis concentrations significantly increased eggs/ embryos mortality and decreased hatching success (p<0.05,  Dunnett’s test). Rates of various physical deformities such as short-tail and lordosis, and the abnormalities such as black pigmentation on yolk sac,  intense lethargy, etc., also climbed with increasing Thalis concentrations (p<0.05, Dunnett’s test). The findings from the current study showed that  Thalis exerts adverse effects on embryo development of C. gariepinus. They constitute an alert on the toxic effect of chemical pesticides used in  Benin on the first developmental stages of fish inhabiting aquatic ecosystems. &nbsp

Diversité et structure de la végétation ligneuse dans la ville de Malanville au Nord-Bénin

La végétation urbaine a le potentiel de relever de nombreux défis environnementaux liés à la durabilité des villes. L’objectif de cette étude était de caractériser la végétation ligneuse de Malanville. La méthode de relevé phytosociologique est utilisée pour la collecte des données. L’échantillonnage aléatoire stratifié a permis d’installer 300 placeaux carrés de 1 ha, générés au hasard par l’outil « Data Management » du logiciel ArcGIS 10.5, suite à un maillage de l’armature urbaine. Le travail a permis de dénombrer 68 espèces  ligneuses réparties 58 genres et 33 familles. La diversité floristique est relativement faible et varie de façon significative (p < 0,05) selon les unités d’occupation des terres (richesse spécifique : 2,75 à 6,75 ; diversité de Shannon : 0,83 à 1,64 bits ; équitabilité de Pielou : 0,48 à 0,63). Les paramètres de structure décroissent significativement (p < 0,01) selon les unités d’occupation des terres (densité moyenne : 6,56 à 59,25 N/ha ; surface terrière : 0,77 à 4,52 m²/ha ; circonférence moyenne : 90,7 à 121,17 cm). La ville de Malanville regorge d’une importante biodiversité floristique constituée à 61% d’espèces exotiques. Dans la recherche de solutions locales aux répercussions deschangements climatiques, cette étude est un atout pour la conservation de la végétation ligneuse urbaine permettant de construire des villes plus durables, attractives et vertes.Mots clés : Diversité floristique, structure de la végétation, végétation en milieu urbain, Malanville, Bénin.English title: Diversity and structure of woody vegetation in the town of Malanville in Northern BeninUrban vegetation has the potential to meet many challenges environmental issues related to the sustainability of cities. The objective of this study was to characterize the woody vegetation of Malanville. The phytosociological survey method was used for data collection. Stratified random sampling allowed the installation of 300 square plots of 1 ha, randomly generated by the "Data Management" tool of the ArcGIS 10.5 software, following a meshing of the urban framework. The work enabled the enumeration of 68 woody species distributed in 58 genera and 33 families. The floristic diversity is relatively low and varies significantly (p < 0.05) according to land use units (specific richness: 2.75 to 6.75; Shannon's diversity: 0.83 to 1.64 bits; Pielou's equitability: 0.48 to 0.63). The structure parameters decrease significantly (p < 0.01) according to the land use units (mean density: 6.56 to 59.25 N/ha; basal area: 0.77 to 4.52 m²/ha; mean circumference: 90.7 to 121.17 cm). The town of Malanville has an important floristic biodiversity, 61% of which is made up of exotic  species. In the search for local solutions to the impacts of climate change, this study is an asset for the conservation of urban woody vegetation, enabling the construction of more sustainable, attractive and greener cities. Keywords : Floristic diversity, vegetation structure, urban vegetation, Malanville, Beni

Effects of hydrogen on trap neutralization in BaSi2 with interstitial silicon atoms

Semiconducting barium disilicide (BaSi2) is one of emerging materials for solar cell applications. Therefore, defect neutralization is very important for improving its solar cell performance. Herein, the effect of atomic hydrogen (H) on the photoresponsivity of 500-nm-thick undoped n-BaSi2 films grown under Si-rich conditions by molecular beam epitaxy was examined, wherein interstitial Si atoms were likely to exist instead of common Si vacancies. The photoresponsivity reached a maximum of ∼1.3 A W−1 at room temperature (about twice as large as that for as-grown films) in BaSi2 films exposed to an atomic H for 10 s. This H treatment time is much smaller than that for BaSi2 films grown under stoichiometric conditions, indicating that interstitial Si atoms provide a smaller trap concentration with respect to the case of Si vacancy domination and incorporation of H atom can neutralize traps. The inverse logarithmic slope (E0) of the Urbach tail was investigated to discuss the dependence of the photoresponsivity of BaSi2 films on H treatment time. There was a clear negative correlation between E0 and photocurrent density obtained from the photoresponsivity. The detailed picture on how interstitial Si atoms affect the electronic structure of BaSi2 by defect state formation and how H atom incorporation modifies the structure is revealed by ab initio calculations that allowed interpreting and understanding of all experimentally observed trends

Application De La Télédétection Et Du Sig Au Suivi Des Formations Végétales De La Forêt Classée Des Trois Rivières Au Nord-Est Du Bénin

The creation of protected areas was intended to counter the advance of the agricultural front and other forms of pressure on natural ecosystems, but today these pressures strongly affect these protected areas. The dynamics of the vegetation was studied in Trois Rivières forest reserve in north-eastern Benin, based on Remote Sensing and GIS techniques. This study aims to analyse the vegetation evolution and determine the drivers of that dynamics using 1995 Landsat TM, 2013 Landsat OLI-TIRS imageries and field surveys. The supervised classification based on the ‘‘Maximum likelihood’’ algorithm was derived from ENVI 5.0 software. The transition matrix derived from Intersect function of ArcToolbox in ArcGIS 9.3 software was used to calculate the different conversion of land cover. The transition matrix was used to measure the intensities and speeds of land cover categories changes from 'PontiusMatrix22' 'and' 'Intensity Analysis02 programs. In addition, 200 household were surveyed from individual interviews and focus group on questionnaires and interview guides basis. The results show that the forest formations decreased from 48 % in 1995 to 20.4 % in 2013. The mosaics of fields and fallows have increased from 3 % to 24 %. The intensity change per land cover category shows that tree and shrub savannahs occurred the most significant change of 73 % of the study area with a 34 % of gain, 32 % of stability and 7 % of loss. In the order hand, the mosaics of fields and fallows, built up areas and dry dense forests occurred the biggest change. According to the perceptions of surveyed people, agriculture, logging and charcoal production are the main direct drivers of Trois Rivières forest reserve degradation