Analysing the Potential Impact of Climate Change on the Hydrological Regime of the Upper Benue River Basin (North Cameroon)

In this study, we analyse the climate variability in the Upper Benue basin and assess its potential impact on the hydrology regime under two different greenhouse gas emission scenarios. The hydrological regime of the basin is more vulnerable to climate variability, especially precipitation and temperature. Observed hydroclimatic data (1950-2015) was analysed using a statistical approach. The potential impact of future climate change on the hydrological regime is quantified using the GR2M model and two climate models: HadGEM2-ES and MIROC5 from CMIP5 under RCP 4.5 and RCP 8.5 greenhouse gas emission scenarios. The main result shows that precipitation varies significantly according to the geographical location and time in the Upper Benue basin. The trend analysis of climatic parameters shows a decrease in annual average precipitation across the study area at a rate of -0.568 mm/year which represents about 37 mm/year over the time 1950-2015 compared to the 1961-1990 reference period. An increase of 0.7°C in mean temperature and 14% of PET are also observed according to the same reference period. The two climate models predict a warming of the basin of about 2°C for both RCP 4.5 and 8.5 scenarios and an increase in precipitation between 1% and 10% between 2015 and 2100. Similarly, the average annual flow is projected to increase by about +2% to +10% in the future for both RCP 4.5 and 8.5 scenarios between 2015 and 2100. Therefore, it is primordial to develop adaptation and mitigation measures to manage efficiently the availability of water resources.

Evaluation of the Efficacy of an Aloe barbadensis Based Biological Insecticide against Pests of Abelmochus esculentus for Promoting Ecological Agriculture (Far-North, Cameroon)

Chemical insecticides have been considered as a means to combat crop pests. Although their effectiveness is evident, their impact on the environment is increasingly being discussed. The aim of this study is to determine the agro-ecological potential of a biological insecticide (C25H32O12) based on Aloe barbadensis in a Sahelian context. For this purpose, a completely randomized block experimental design with 3 replications and 4 treatments was set up to experiment with Aloe barbadensis as a bioinsecticide against pests of Abelmoschus esculentus. However, data were collected using an observation and parameter monitoring grid. This includes the cultivation of Abelmoschus esculentus, soil preparation, seeding and watering, plot labeling, preparation of the bioinsecticide (selection and preparation of raw materials, grinding of Aloe barbadensis miller and extraction of the crude bioinsecticide, quantification of treatment doses and dilution, and obtaining the formulated bioinsecticide), plant watering, plant treatment, and finally parameter monitoring. The results obtained reveal that the level of damage is significantly high in the control treatment T0 (63%) compared to the other treatments, with 29% for treatment T1, 7% for T2, and 1% for T3, implying a strong action capability of this insecticide against pests of Abelmoschus esculentus. Therefore, it can be concluded that for a normal growing season of Abelmoschus esculentus, this biological insecticide should be sprayed 12 times. Furthermore, this biological insecticide is unique in that it does not inflict any gastric toxicity on the pests, which gives it the characteristic of being a repellent. It is a biological insecticide whose efficacy period has been tested, with a minimum duration of 21 days. In conclusion, this formulated bioinsecticide based on Aloe barbadensis demonstrates significant efficacy against pests of Abelmoschus esculentus. In the future, we will consider experimenting with its effectiveness against pests of other plants.

Ethnobotanical Study of Medicinal Plants Used for Treating Urinary Tract Infections in N’Djamena (Chad)

Introduction: Infection disease is a real publique health problem. The rise of resistance for modern antibiotic in infections treatment imposed us order alternatives. The study objective was to contribute in the knowledge of medicinal plants uses in urinary infections treatment in N’Djamena (Chad) in view for amelioration the traditional medicine in future. Methodology: The study was conducted in the city of N’Djamena in the Republic of Chad that interviewed 60 traditherapists on using 11 plants for urinary tract infections treatment. The methodology of this study consisted of the knowledge of medicinal plants that used by traditherapists, and the plants identification was done in the laboratory of IRED at Farcha. Results: A total of 60 traditherapists was interrogated on the plants used in the treatment of urinary tract infections among the population of N’Djamena. The majority of traditherapists interrogated in this study were male with the rate of 61.67% against female with the rate of 38.33%. The age range of traditherapists was between 20 to 80 years, 25 (41.67%) from the age range between 30 - 50 years and 35 (58.33%) in age range from 50 to 70 years. For the origin of their knowledge, the study showed that 72% of traditherapists inherited the knowledge from their family, while 15% inherited from the family and from training. The ethnic groups of the traditherapists were Sara (16%), Maraba (12%) and Massa (11%). According to the results, 18.33% were illiterates, 49% attended primary school and 33.34% the secondary school. Our study found that 11 species of plants belonging to 11 families were used in the treatment of urinary tract infection and the Ziziphus spina-christi was the most represented. According to traditherapists the Ziziphus spina-christi, Cassia obovata and Euphorbia hirta were the most frequent plants used in the urinary tract infections treatment. The parts of plants used in the treatment were leaves and bark, grained leaves and entire plants with the proportion of 50%, 16.67 and 15% respectively. Conclusion: This study revealed that the medicinal plants are variously used in the treatment of infection urinary tract in the city of N’Djamena.

Problematic of Accounting Evolutivity: An Answer Through the Analysis of SYSCOHADA in the Cameroonian Context

This article describes the conceptual, practical, and organizational difficulties of evolutivity of a new uniform act. Besides the problem of stock market listing of most African countries enterprises seen among many other things as a prerequisite to the internationalization of accountancy, particularly, to the emergency of the full or total or not at all implementation of an innovation, it is a matter of bringing the foundations into focus. The most expected heated debates on the SYSCOHADA accounting evolutivity in view of the implementation of its new uniform act, of the quality of information provided and the informational pertinence are therefore collected through semi-direct interviews from accountants and auditors. A situational analysis is carried out in the Cameroonian context. From a qualitative approach, the potential constraints are explained. The interest of the analysis of this evolutivity is that, despite its temporal status, it is intimately linked to organizational and social realities.

Contribution to Improving the Management of Sewage Sludge in the Western Region: Case of Bafoussam 1st

Sanitation is a particularly sensitive issue in the world, especially in Africa where local communities are plagued by the problem of managing sludge which is causing a lot of damage in Africa and mainly in Cameroon. This study aims to contribute to improving the management of sewage sludge in the municipality of Bafoussam 1st. For this study, the methodology used is field survey. The questionnaire was submitted to 120 households in the commune of Bafoussam 1st, in particular, we take into account knowledge of the health and environmental risks that can result from improper handling of sludge and its treatment. The results show that the most widespread sanitation system is traditional latrines. Similarly, 79.19% of those surveyed dump, the sludge collected at the landfill against only 14.28% who dump it in fields and 6.53% have no idea about the fate of the sludge from their sanitary facilities. It should also be noted that 55.83% of the people surveyed are not aware of the health and environmental risks of untreated sewage sludge and therefore do not take the precautions to avoid it. Subsequently, 93.75% of respondents say that the current landfill would be a nuisance and the main nuisances identified are water pollution and subsequent fish poisoning. Physico-chemical analyzes of the sludge revealed values much higher than the values provided for by the WHO standards. Thus, total nitrogen and phosphate ions represented respectively 97 mg/L and 47 mg/L against 35 and 30.4 mg/L for the standard;COD and BOD5 represented respectively 3250 mg/L and 1100 mg/L against 150 and 40 mg/L provided by the WHO standards. It follows the temperature and the MES which gave values of 32.7°C and 1750 mg/L, values much higher than the standard (30°C and 50 mg/L).

Recovery of Organic Waste with Other Biological Components for the Production of Organic Fertilizer: Improved Biochar

The study was carried out in Baham district in the West Cameroon region, as part of the recovery of organic waste with other biological components for the manufacture of an organic fertilizer (improved biochar). Through observations and a survey questionnairy submitted to 100 farmers, it appears that the majority use synthetic chemical fertilizers. Farmers using chemical fertilizers find them dangerous to their health. In addition, 58.57% of these farmers said they felt unwell after spreading these fertilizers. However, 64.28% of these farmers do not acquire PPE for reasons of financial means on the one hand and ignorance on the other hand. 54.28% of respondents using only chemical fertilizers noted declining agricultural production. The surveys also reveal that biochar (of plant origin) as a solution proposed by CIPCRE is used by a minority of farmers (21%) in the said locality on the one hand and on the other hand has limits in terms of intake nutrients for crops;this was confirmed by analyzes of the physico-chemical parameters.

Proposal for Energy Consumption Reduction between Connected Objects in a Network Running on MQTT Protocol

The “Internet of Things” (IoT) refers to a set of intelligent “objects” that can communicate with each other directly or through a network. The IoT is the embodiment of the idea that everything can be connected anywhere and at any time. The concept can be applied to sectors such as e-health, e-government, automotive, geographic information systems, remote sensing, home networking, e-commerce and climate change mitigation. Unlike the Internet, the IoT has its own constraints, notably those linked to heterogeneity. This divergence is linked to different protocols, technologies and algorithms implemented in these connected objects for their interconnection. It should be noted that IoT devices can communicate with each other using different protocols and dedicated M2M (Machine to Machine) communication technologies. The aim of this work is to find solutions for optimising energy consumption during data exchanges between connected objects, with respect to certain constraints by using firstly this exchange for only Message Queuing Telemetry Transport (MQTT) and secondly the combination of the MQTT protocol and the Constrained Application Protocol (CoAP) protocol to check the quantity of the energy optimized. The MQTT protocol, for example, is one of the most widely used protocols for connected objects. Admittedly, this protocol consumes less energy, but in the situation of a very large number of users, the problem of saturation inevitably arises. In this article, we propose a solution of optimising energy consumption by combining the MQTT protocol with the CoAP protocol which can allow to use the standby mode contrary to the use of MQTT where the broker is always being turning. This solution has not yet been implemented but is being discussed. In this article, we’re going to use the joulemeter which is an application developed by Microsoft to measure and estimate the energy consumption of computers and applications. In our case, we take the example of the “Service Broker for network connections” of the Windows’s 10 Operating System, in my own computer to show the difference between the consumption of energy without the standby mode and with standby mode, because with the MQTT, the Broker’s MQTT is always on. Now, with the combination MQTT and CoAP, it is possible that we have standby mode and to compare these two cases in term of consumption of an energy. And to do it, we must use the joulemeter that we installed in our computer to simulate it. This is achieved by using the CoAP protocol combined with the MQTT protocol. The aim of our work is to reduce energy consumption in order to solve the problem of saturation of the MQTT by linking it to CoAP protocol by using Joulemeter mentioned above.

Physico-Mechanical Properties of Bio-Based Bricks

The aim of this work is to improve the high performance of mud bricks. The latter was reinforced with rice straws as stabiliser leading to an improvement of the physico-mechanical properties. Thus, the physical characteristics of the clay such as natural water content, density, atterberg limit, plasticity limit (Wp) and plasticity index (Ip) were determined. Their values are respectively 8.39%, 2025.73 Kg/m3, 47.66%, 29.75% and 17.91%. The clay used is a low plastic organic silt. The normal proctocol provided an optimum dry density (ɣOP) of 1.28 Kg/m3 at an optimum moisture content of 12.42%. The actual density of the straw is 464 Kg/m3, its absorption rate reached 206% in 5 mins and stabilised at 385% at 480 mins of immersion. The maximum bending and compression strengths are respectively 1.52 and 0.164 MPa. The mud brick absorption coefficients obtained are between 4.875 at 0% straw and 20.573% at 3% straw.

Highly Hazardous Pesticides (HHPs) Registered andTheir Use in Sub-Saharan Africa

To sustain agricultural production,pesticides are highly recommanded.In sub-Saharan Africa,two regulatory bodies are in charge of pesticide registration,for more than 10 years of duty,the impact of their activity has not yet best carried out.The present investigation aimed to evaluate the evolution in the quality of pesticides in agriculture in sub-Saharan Africa.Registration of pesticides began in Cameroon in 1996.There,less than 5%of pesticides used in 2004 were registered and more than 80%of producers were not aware of this legal process.In 2014,85%of pesticides used are registered.In sub-Saharan Africa,Highly Hazardous Pesticides(HHPs)registered are rondenticides,insecticides and nematocides.They are frequently used for the protection of stored products.Ilicit Persistent Organic Pollutants(POPs)(heptachlore,chlorobenzene)and HHP(alluminium phosphide,terbufos,abamectine,ethropophos,etc.)are frequently used to protect stored grains.And 40%are registered for use in intensive bananas production(28%for nematodes control alone and 10%for control of both insects and nematodes).Moreover,20%of HHPs registered are for the control of rondents.

An Evolutionary Algorithm Coupled to an Outranking Method for the Multicriteria Shortest Paths Problem

In this article, we are interested in solving a combinatorial optimization problem, the shortest path problem in a multi-attribute graph, by the out-ranking methods. A multi-attribute graph has simultaneously qualitative and quantitative criteria. This situation gives rise to incomparable paths thus forming the Pareto front. Outranking methods in Multi-criteria Decision Making (MCDM) are the only methods that can take into account this situation (incomparability of actions). After presenting the categories of Multi-criteria Decision Making (MCDM) and the difficulties related to the problems of the shortest paths, we propose an evolutionary algorithm based on the outranking methods to solve the problem of finding “best” paths in a multi-attribute graph with non-additive criteria. Our approach is based on the exploration of induced subgraphs of the outranking graph. Properties have been established to serve as algorithmic basis. Numerical experiments have been carried out and the results presented in this article.

Lithostructural controls in Douala-Buea Region landscape (SW Cameroon margin):Insights from morphometric analysis

The Douala-Buea Region(DBR;4°-5°N,9°-10°30’E),a portion of the southern Cameroon passive margin,developed on the Proterozoic granito-gneissic basement and the Cretaceous to Recent volcanosedimentary cover,was explored in order to evaluate the lithology and tectonics controls on its landscape usingthequalitativeandquantitative geomorphological analyses based on 30 m resolution Digital Elevation Models(DEM)and field evidences.This area displays an uneven and complex landscape differentiated into four morphological units:Douala,Nkondjock,Kumba and Buea Units.The Douala Unit corresponds to the Coastal Plain and is extended on the Douala-Kribi/Camposedimentarybasin.The Nkondjock Unit represents a middle plateau developed on a Proterozoic granito-gneissic basement.The Kumba Unit matches with the southernmost volcanic Western Cameroon High Plateau.The Buea Unit corresponds to the Mount Cameroon stratovolcano.The relief analysis through mountain-front sinuosity(Smf,1.19–1.43)and relative relief ratio(Rr,0.10–2.31)vary from one unit to another.The drainage network analysis including drainage patterns,stepped longitudinalriverprofiles,theassociated morphometric indexes,notably the concavity index(IC,0.56–0.88),deviation(D,267–2912 m),basin asymmetry factor(A_(F),6.37–42.12),hypsometric integral(HI,0.10–0.29),valley floor width to valley height ratio(V_(f),0.36–2.75),elongation ratio(R_(e),0.30–0.50),watershed slope(S,6.88–88.88)and stream length gradient index(SL,0–3332)vary from one basin to another too.These results also show the heterogeneous and uneven DBR landscape controlled by its lithology and active tectonics.The drainage system reveals concave to concavo-convex longitudinal river profile shapes with knick points,asymmetric basins,and fault reactivations,and highlights the tectonics activity that used to occur through the time and their control on the morphology.Together,they document the lithostructural controls on the DBR landscape evolution,extendable in the whole SW Cameroon margin.

Dynamic analysis,FPGA implementation,and cryptographic application of an autonomous 5D chaotic system with offset boosting

An autonomous five-dimensional(5D)system with offset boosting is constructed by modifying the well-known three-dimensional autonomous Liu and Chen system.Equilibrium points of the proposed autonomous 5D system are found and its stability is analyzed.The proposed system includes Hopf bifurcation,periodic attractors,quasi-periodic attractors,a one-scroll chaotic attractor,a double-scroll chaotic attractor,coexisting attractors,the bistability phenomenon,offset boosting with partial amplitude control,reverse period-doubling,and an intermittency route to chaos.Using a field programmable gate array(FPGA),the proposed autonomous 5D system is implemented and the phase portraits are presented to check the numerical simulation results.The chaotic attractors and coexistence of the attractors generated by the FPGA implementation of the proposed system have good qualitative agreement with those found during the numerical simulation.Finally,a sound data encryption and communication system based on the proposed autonomous 5D chaotic system is designed and illustrated through a numerical example.

Diverse chirped optical solitons and new complex traveling waves in nonlinear optical fibers

This paper studies chirped optical solitons in nonlinear optical fibers.However,we obtain diverse soliton solutions and new chirped bright and dark solitons,trigonometric function solutions and rational solutions by adopting two formal integration methods.The obtained results take into account the different conditions set on the parameters of the nonlinear ordinary differential equation of the new extended direct algebraic equation method.These results are more general compared to Hadi et al(2018 Optik 172545–53)and Yakada et al(2019 Optik197163108).