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Stability of a Delayed Stochastic Epidemic COVID-19 Model with Vaccination and with Differential Susceptibility

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Journal of Applied Mathematics and Physics 2024年第2期12卷 509-532页

作者： modeste N’zi Boubacar Sidiki Kouyaté Ilimidi Yattara Modibo Diarra Laboratory of Applied Mathematics and Computer Science University Felix Houphouet-Boigny Abidjan C&#244te d’Ivoire Department of Mathematics and Computer Science University of Science Technic and Technologies Bamako Mali

In this paper, we treat the spread of COVID-19 using a delayed stochastic SVIRS (Susceptible, Infected, Recovered, Susceptible) epidemic model with a general incidence rate and differential susceptibility. We start with a deterministic model, then add random perturbations on the contact rate using white noise to obtain a stochastic model. We first show that the delayed stochastic differential equation that describes the model has a unique global positive solution for any positive initial value. Under the condition R0 ≤ 1, we prove the almost sure asymptotic stability of the disease-free equilibrium of the model.

关键词： SIRS Delayed Epidemic Model Nonlinear Incidence rate Lyapunov Function Asymptotic Stability in Probability

Evaluation of Agricultural Contamination Level by Heavy Metals and Pesticides in Sediments of Rivers and water Bodies for Shrimp Fishing in the Lower Ouémé: Case of the Aguigadji, Ahlan and Sele Stations in Benin

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Advances in Materials Physics and Chemistry 2024年第2期14卷 25-46页

作者： Souradjou Orou Goura Fadéby modeste Gouissi Armelle Sabine Yélignan Hounkpatin wakili Bolatito Yessoufou Tayéwo Sylvain Biaou Nonvignon Martial Fassinou Laboratory of Ecology Health and Animal Production (LESPA) Faculty of Agronomy (FA) University of Parakou (UP) Parakou Bénin Pluridisciplanary Research Laboratory for Technical Education (LARPET) University of Sciences Technologies Engineering and Mathematics of Abomey (UNSTIM) Lokossa Bénin

This study assessed sediment contamination by heavy metals and pesticide active ingredients linked to chemical inputs used in agricultural activities in the lower Ouémé. Pesticide residues from the organochlorine, pyrethroid and organophosphorus families were investigated by gas chromatography, and heavy metals (Cd, Pb, As, Ni, Zn, Fe, Mg, Cr and Hg) by atomic absorption spectrophotometry. The metallic pollution indices, the contamination factor (CF) and the ecological risk index were calculated. The results revealed 8 active ingredients in the rainy season and 9 in the dry season. Glyphosate was the active ingredient with the highest concentration at all stations, 9.65 ± 0.84 mg/kg recorded in the dry season at the Aguigadji station. All glyphosate values were above the EQS. DDT, Atrazine and Endosulfan also showed high concentrations in the dry and rainy seasons. Emamectin, Abamectin and Lambda Cyhalothrin also showed high concentrations in the dry season at Aguigadji, Ahlan and Sele. Only glyphosate was recorded at the control station (Toho), but in very low concentrations. Lead showed the highest concentrations at all the stations, 265.96 ± 21.02 mg/Kg in the rainy season and 255.38 ± 79.09 mg/Kg in the dry season, all detected at the Aguigadji station and above the EQS. Zn, Ni, Fe, Cu and Cr were all representative in both the dry and rainy seasons at the contaminated stations. Manganese showed high concentrations in the rainy season. Pb showed very high contamination (FC ≥ 6) at the Aguigadji and Ahlan stations and significant contamination (3 ≤ FC 6) at the Sele station in both the rainy and dry seasons. Ni, Hg and Cd, showed either moderate or significant contamination at the contaminated stations. The risk values showed a considerable ecological Ri (190 ≤ Ri < 380) in the rainy season and a moderate ecological Ri (95 ≤ Ri < 190) in the dry season at these contaminated stations.

关键词： Pesticides Heavy Metals Sediments Shrimp Fishing Area Lower Ouémé

Impact of Dewatering on the Spatio-Temporal Distribution of Benthic Macroinvertebrate Communities in the Okpara River, Benin

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Journal of Geoscience and Environment Protection 2024年第2期12卷 30-43页

作者： Sylvain Tayéwo Biaou Fadéby modeste Gouissi Armelle Sabine Yélignan Hounkpatin Zoulkanerou Orou Piami wakili Bolatito Yessoufou Souradjou Orou Goura Nonvignon Martial Fassinou Laboratory of Ecology Health and Animal Production (LESPA) Faculty of Agronomy (FA) University of Parakou (UP) Parakou Benin Pluridisciplanary Research Laboratory for Technical Education (LARPET) University of Sciences Technologies Engineering and Mathematics of Abomey (UNSTIM) Lokossa Benin

Surface watercourses are areas of very high ecological and heritage value. Macroinvertebrates are bioindicators of the health of aquatic ecosystems. The aim of this study was to assess the effects of dewatering and re-watering cycles on benthic macroinvertebrate (BMI) communities. Two data collections were carried out at two stations (Okpara 1 and Okpara 2) on the Okpara river before and after dewatering. Thus, 8 samples of benthic macroinvertebrates and 12 physico-chemical parameters (T°C, pH, Transparency, Depth, Conductivity, Dissolved Oxygen that were measured in situ, and BOD5, COD, NH4+, NO3-, NO2- and PO43-) were assayed in the laboratory. Canonical Correspondence Analysis (CCA) was used to match physico-chemical data to MIB families. Shannon and Piélou diversity indices were used to determine the effects of dewatering on MIBs. The increase in temperature values of pH, BOD5, COD, NH4+, NO3-, NO2- and PO43-, after re-watering indicates the effect of dewatering on the quality of Okpara aquatic ecosystems. The benthic macrofauna collected consisted of 62.42% insects, 0.65% crustaceans, 6.48% molluscs, 0.72% worms and 0.14% arachnids. Whereas after re-watering, 21.67% insects, 0% crustaceans, 0.22% molluscs, 7.56% worms and 0.29% arachnids were recorded. Insects, crustaceans and molluscs were more abundant before dewatering than after. This was revealed by low abundances and taxonomic richness, as well as low Shannon index values of samples collected after re-watering.

关键词： Dewatering Benthic Macroinvertebrates Impact Physico-Chemical Parameters Okpara Rivers Nord-Benin

Aframomum melegueta prevents the ejaculatory complications of propylthiouracil-induced hypothyroidism in sexually experienced male rats: Evidence from intravaginal and fictive ejaculations

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Journal of Integrative Medicine 2019年第5期17卷 359-365页

作者： Francois Xavier Kemka Nguimatio Patrick Brice Deeh Defo modeste wa.keu-nya Esther Ngadjui Albert Kamanyi Pierre Kamtchouing Pierre watcho Animal Physiology and Phytopharmacology Laboratory University of DschangP.O. Box 67DschangCameroon Department of Animal Organisms Biology University of DoualaP.O. Box24157 DoualaCameroon Department of Animal Biology and Physiology University of Yaounde 1P.O. Box 812YaoundeCameroon

Objective: Hypothyroidism has been claimed to generate sexual dysfunctions such as ejaculatory disorders. Aframomum melegueta is an aphrodisiac plant with pro-ejaculatory properties. We investigated the protective effects of aqueous extract(AE) and methanolic extract(ME) of A. melegueta on the ejaculatory function of hypothyroid male ***: Forty sexually experienced male rats were partitioned into 8 groups(5 rats per group) and treated for 28 d as follows: Group 1, Control;Group 2, propylthiouracil(PTU, 10 mg/kg)+ distilled water(DW,10 m L/kg);Group 3, PTU + 5% Tween 80(10 m L/kg);Group 4, PTU + bromocriptine(6 mg/kg);Group 5,PTU + AE(20 mg/kg);Group 6, PTU + AE(100 mg/kg);Group 7, PTU + ME(20 mg/kg), and Group 8,PTU + ME(100 mg/kg). On days 0, 7, 14 and 28 of treatment, each male rat was paired with primed receptive female for measurement of ejaculatory latency time(ELT) and post-ejaculatory interval(PEI) for1.5 h. On day 29, each male rat was urethane-anesthetized and the spinal cord was ***, following urethral/penile stimulations and intravenous injection of dopamine, contractions of the bulbospongiosus muscles and the intraseminal pressure were registered. After these recordings,blood was collected through the catheterization of abdominal artery and plasma was used for thyroidstimulating hormone(TSH), prolactin and testosterone ***: PTU-induced hypothyroidism was characterized by a significant elevation(P wa

关键词： Propylthiouracil Hypothyroidism Ejaculation Bromocriptine Aframomum melegueta

Granulometric and Mineralogical Characterization of the Sands of the Middle Course of the Kasai River (Territory of Ilebo, Province of Kasai/DR Congo)

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Journal of Geoscience and Environment Protection 2024年第7期12卷 50-71页

作者： Lowny Trésor Madienga Kitshabi Ivon Ndala Tshiwisa modeste Kisangala Muke Thomas Kanika Mamena Dominique Wetshondo Osomba Emmanuel Cibambula Musau Adalbert-Jules Makutu Ma Ngwayaya Department of Petroleum Exploration and Production Faculty of Oil Gas and Renewable Energies University of Kinshasa Kinshasa Democratic Republic of the Congo Department of Geosciences Faculty of Sciences and Technologies University of Kinshasa Kinshasa Democratic Republic of the Congo

The sand bars, in perpetual transformation, observable in the middle course of the Kasai river on the section between the city of Ilebo (pk605) to the confluence of the Loange river (pk525), pose enormous navigability problems. This may be dependent on hydrosedimentological characteristics of the Kasai River. This abundance of sand thus conditions the morphology of the middle course of the Kasai River in the section under our study. It therefore constitutes sedimentary navigation obstacles. The objective of this study is the granulometric and mineralogical characterization of the bar sands of the Kasai River in this study section. Particle size analyzes reveal these are moderately well classified to well classified unimodal sands (Classification coefficient between 1.29 to 1.742) largely presenting grain size symmetry and rarely fine asymmetry (Asymmetry coefficient—Skewness between −0.197 to 0.069) with mesorkurtic and rarely leptokurtic and platykurtic acuity (Angulosity coefficient—Kurtosis between 0.814 to 1.323). All these parameters evolve in sawtooth patterns from upstream to downstream. And then, an automated mineralogical analysis of the sands of the Kasaï River using a Qemscan FEG Quanta 650 made it possible to determine a very varied mineralogical procession with a sawtooth evolution. It is largely dominated by quartz (between 93.73% and 99.07%), followed by calcite (0.01% - 2.66%), iron oxides (0.01% - 1.88%), orthoclase (0.04% - 0.99%), plagioclase (0.01% - 0.75%) and Kaolinite (0.18% - 0.71%). Finally, this mineralogical procession is characterized by a group of minerals which do not reach the threshold of 0.55% such as: illite, apatite, ilmenite, muscovite, chlorite, biotite, montmorillonite, rutile, pyrophyllite, siderite, zircon and dolomite. The evolution of the mineralogical procession of the sands of the bars is not as clear as in the case of particle size parameters.

关键词： Characterization Granulometric Mineralogical Sands Middle Course Kasai River

Agricultural Contamination of the Surface waters of the Upper Ouémé in Benin: The Case of Heavy Metals and Pesticides

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Journal of Agricultural Chemistry and Environment 2024年第1期13卷 83-99页

作者： Armelle Sabine Yélignan Hounkpatin Nonvignon Martial Fassinou Fadéby modeste Gouissi Zoulkanerou Orou Piami Dossou Armel Géraldo Houndeton Souradjou Orou Goura wakili Bolatito Yessoufou Tayéwo Sylvain Biaou Laboratory of Hygiene Sanitation Toxicology and Environmental Health (HECOTES) The Training Centre Interfacultaire and Environmental Research for Sustainable Development (CIFRED) of the University of Abomey (UAC) Cotonou Benin Plurildisciplinary Research Laboratory for Technical Education (LARPET) of the University of Sciences Technologies Engineering and Mathematics of Abomey (UNSTIM) Lokossa Benin Laboratoire d’Ecologie de Santé et de Productions Animales (LESPA) Faculté d’Agronomie (FA) Université de Parakou (UP) Parakou Bénin

Objective: The main objective of this study was to assess the degree of contamination of surface waters by heavy metals and pesticides. Method: To this end, data were collected in December 2022 from four specific sampling stations: Okpara, Térou, Affon and Adjiro. Levels of heavy metals, including cadmium, chromium, copper, iron, mercury, nickel and lead, were measured and subjected to in-depth statistical analysis using graphical summation models. In addition, the concentrations of pesticide active ingredients present in the samples were interpreted and evaluated. The statistical data collected during this study were processed using R software, version 3.5.0. Results: The values obtained at the different stations Okpara, Térou, Affon and Adjiro are respectively Arsenic (2 × 10-4 mg/L;2.2 × 10-1 mg/L;1.2 × 10-4 mg/L;2 × 10-4 mg/L), Cadmium (4.4 × 10-5 mg/L;1.1 × 10-2 mg/L;10-4 mg/L;4 × 10-4 mg/L). Then Copper (7 × 10-4 mg/L;3 × 10-3 mg/L;7 × 10-4 mg/L;1 × 10-4 mg/L), Iron (1.51 mg/L;6.4 × 10-1 mg/L;2.0012 mg/L;2.9 × 10-1 mg/L), Lead (0 mg/L;0 mg/L;1.5 × 10-3 mg/L;1.5 × 10-3 mg/L). Mercury, nickel and chromium were not detected in surface waters. It is important to note that the values obtained for trace metals (Cadmium, Chromium, Copper, Iron, Mercury, nickel and chromium were not detected in surface waters. It is important to note that the values obtained for trace metals (cadmium, chromium, copper, iron, mercury, nickel and lead) were all below the guideline standards set by the WHO in 2006 for uncontaminated surface waters. This indicates that the surface waters of the Upper Ouémé were below acceptable contamination thresholds in terms of heavy metals. However, the presence of pesticide active ingredients such as cyfluthrin, endosulfan-alpha, endosulfan-beta, profenosfos, tihan, atrazine, g

关键词： Agricultural Contamination Heavy Metals Pesticides Surface water North Benin

Cyclophosphamide-induced reproductive toxicity: Beneficial effects of Helichrysum odoratissimum(Asteraceae) in male Wistar rats

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Journal of Integrative Medicine 2019年第5期17卷 366-373页

作者： Pierre watcho Ismaelle Rosine Mpeck Patrick Brice Deeh Defo modeste wa.keu-nya Esther Ngadjui Georges Romeo Bonsou Fozin Pierre Kamtchouing Albert Kamanyi Animal Physiology and Phytopharmacology Laboratory University of DschangP.O. BOX 67DschangCameroon Department of Animal Organisms Biology University of DoualaP.O. BOX 24157DoualaCameroon Department of Animal Biology and Physiology University of YaoundeP.O. BOX 812YaoundeCameroon

Objective: Cyclophosphamide(CP) is commonly used to treat some cancers, but its clinical efficacy is also linked with testicular toxicity. We investigated the effects of aqueous extract(AE) and methanolic extract(ME) of Helichrysum odoratissimum for reducing CP-induced reproductive toxicity in male ***: In addition to a normal control(group 1), drugs or vehicles were administered orally to seven groups(n = 5) of rats that had already received 4-weeks of pre-treatment with CP(5 mg/[kgád], per oral administration);group 2 received CP + distilled water(10 m L/[kgád]);group 3 received CP + 5% tween 80(10 m L/[kgád]);group 4 received CP + clomiphene citrate(0.25 mg/[kgád]);groups 5 and 6 received CP + AE(50 and 100 mg/[kgád]) and groups 7 and 8 received CP + ME(50 and 100 mg/[kgád]). Animals were sacrificed on day 15, and body and sexual organ weights, sperm characteristics, testosterone level and testicular histology were ***: The CP-treated group showed a significant reduction(P < 0.001) in the body and seminal vesicle weights, testosterone level, sperm count, sperm motility and sperm viability, but elevated(P < 0.001)sperm morphological abnormalities and testicular structure alterations, compared to the control ***, these detrimental effects of CP were reversed by treatment with H. odoratissimum *** instance, both extracts and all doses of H. odoratissimum significantly increased the sperm count(P < 0.001), sperm motility(AE, 50 mg/kg, P < 0.05;ME, 50 and 100 mg/kg, P < 0.05) and sperm viability(AE, 50 mg/kg, P < 0.001;ME, 50 and 100 mg/kg, P < 0.001) compared to the CP group. H. odoratissimum also improved plasmatic and intratesticular testosterone levels and prevented histological alterations of the ***: H. odoratissimum might be considered as an alternative drug to alleviate/prevent reproductive damage in cancer patients receiving CP chemotherapy.

关键词： Helichrysum odoratissimum Cyclophosphamide Reproductive toxicity Rat

Assessment of forest dieback on the Moroccan Central Plateau using spectral vegetation indices

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Journal of Forestry Research 2023年第3期34卷 793-808页

作者： Youssef Dallahi Amal Boujraf modeste Meliho Collins Ashianga Orlando Laboratory of Microbial Biotechnologies Agrosciences and Environment(BioMAgE)Faculty of Sciences SemlaliaCadi Ayyad UniversityMarrakechMorocco Laboratoire des Productions Végétale Animales et Agro-industrieEquipe de BotaniqueBiotechnologie et Protection des PlantesFacultédes SciencesUniversitéIbn TofailKenitraMorocco Sociétés TerritoiresHistoires et PatrimoinesFacultédes Lettres et des Sciences HumainesUniversitéMohammed VRabatMorocco Rabat Morocco

Cork oak forests in Morocco are rich in resources and services thanks to their great biological diversity,playing an important ecological and socioeconomic *** degradation of the forests has been accentuated in recent years by signifi cant human pressure and eff ects of climate change;hence,the health of the stands needs to be *** this study,the Google Engine Earth platform was leveraged to extract the normalized diff erence vegetation index(NDVI)and soil-adjusted vegetation index,from Landsat 8 OLI/TIRS satellite images between 2015 and 2017 to assess the health of the Sibara Forest in *** results highlight the importance of interannual variations in NDVI in forest monitoring;the variations had a signifi cantly high relationship(pwas positively and negatively correlated with mean annual precipitation and mean annual temperature with respective coeffi cients of 0.49 and−0.67,highlighting its ability to predict phenotypic changes in forest *** interannual variation in NDVI between 2016 and 2017 seemed to confi rm fi eld observations of cork oak dieback in 2018,with the largest decreases in NDVI(up to−38%)in December in the most-aff ected *** of the infl uence of ecological factors on dieback highlighted the role of substrate as a driver of dieback,with the most severely aff ected plots characterized by granite-granodiorite substrates.

关键词： Forest health monitoring Remote sensing Dieback Vegetation indices Sibara forest

The methanolic extract ofGuibourtia tessmannii(Caesalpiniaceae)improves sexual parameters in high fat diet-induced obese sexually sluggish rats

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Asian pacific Journal of Reproduction 2017年第5期6卷 202-211页

作者： Patrick Brice Deeh Defo modeste wa.keu-nya Esther Ngadjui Georges Romeo Bonsou Fozin Francois Xavier Kemka Albert Kamanyi Pierre Kamtchouing Pierre watcho Animal Physiology and Phytopharmacology Laboratory University of DschangBox 67 DschangCameroon Department of Animal Organisms Biology University of Douala-Cameroon Department of Animal Biology and Physiology University of Yaoundé1YaoundéCameroon

Objective:To evaluate the effects of the methanolic extract ofGuibourtia tessmannii (G. tesmannii) on sperm parameters, lipid profile and testosterone level in obese ***: A total of 193 male Wistar rats were fed either with palm oil diet (n=185) or standard diet (n=8) for 16 wk. At the end of this feeding period, 90 obese rats were selected and randomly divided into 18 groups of five rats each and treated with distilled water (10 mL/kg), vitamin E (75 mg/kg), clomiphene citrate (2 mg/kg) or methanolic extract ofG. tessmannii (55, 110 or 220 mg/kg) for 7, 21 or 56 d. At the end of each treatment period, sperm parameters, lipid profile and testosterone level were evaluated. Data were analyzed using ANOVA for repeated measures followed by post-hoc Tukey HSD (P<0.05) for multiple ***: Feeding of rats for 16 wk with palm oil diet significantly damaged sperm parameters. The methanolic extract ofG. tesmannii improved sperm viability, motility and normality after 21 or 56 d of treatment. The sperm normality increased significantly in rats treated with the methanolic extract ofG. tesmannii for 7 (110 mg/kg,P<0.01) and 56 d (110 and 220 mg/kg,P<0.05) compared to control group. Triglycerids, total cholesterol, low and very low density lipoproteins cholesterol levels were lower in rats treated with the plant extract for 56 d.G. tesmannii also significantly increased the high density lipoprotein cholesterol and testosterone levels in the plasma after 56 d of ***: The methanolic extract ofG. tesmannii can improve sperm parameters, lipid profile and testosterone level in obese rats. These findings may justify the folkloric use ofG. tesmannii as a reproductive performance enhancer.

关键词： Guibourtia tessmannii Palm oil diet Sperm parameters Lipid profile Testosterone