检索结果-南通市图书馆

Asymptotic Analysis of a Stochastic Model of Mosquito-Borne Disease with the Use of Insecticides and Bet Nets

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Applied Mathematics and Physics 2024年第1期12卷 305-329页

作者： boubacar Sidiki Kouyaté Modeste N’zi Department of Mathematics and Computer Science University of Science Technical and Technologies of Bamako Bamako Mali Laboratory of Applied Mathematics and Computer Science University Felix Houphouet-Boigny Abidjan C&#244te d’Ivoire

Ross’ epidemic model describing the transmission of malaria uses two classes of infection, one for humans and one for mosquitoes. This paper presents a stochastic extension of a deterministic vector-borne epidemic model based only on the class of human infectious. The consistency of the model is established by proving that the stochastic delay differential equation describing the model has a unique positive global solution. The extinction of the disease is studied through the analysis of the stability of the disease-free equilibrium state and the persistence of the model. Finally, we introduce some numerical simulations to illustrate the obtained results.

关键词： Vector-Borne Disease Epidemic Model Stochastic Delay Differential Equations Stochastic Stability Lyapunov Functional Technique

A Hybrid Learning Algorithm for Breast Cancer Diagnosis

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Intelligent Learning Systems and Applications 2024年第3期16卷 262-273页

作者： Alio boubacar Goga Harouna Naroua Chaibou Kadri Laboratoire dInformatique Fondamentale et Applique-Sciences de lIngnierie (LIFA-SI) Dpartement de Mathmatiques et Informatique Facult des Sciences et Techniques Universit Abdou Moumouni Niamey Niger

In many fields, particularly that of health, the diagnosis of diseases is a very difficult task to carry out. Therefore, early detection of diseases using artificial intelligence tools can be of paramount importance in the medical field. In this study, we proposed an intelligent system capable of performing diagnoses for radiologists. The support system is designed to evaluate mammographic images, thereby classifying normal and abnormal patients. The proposed method (DiagBC for Breast Cancer Diagnosis) combines two (2) intelligent unsupervised learning algorithms (the C-Means clustering algorithm and the Gaussian Mixture Model) for the segmentation of medical images and an algorithm for supervised learning (a modified DenseNet) for the diagnosis of breast images. Ultimately, a prototype of the proposed system was implemented for the Magori Polyclinic in Niamey (Niger) making it possible to diagnose (or classify) breast cancer into two (2) classes: the normal class and the abnormal class.

关键词： Image Diagnosis Segmentation DenseNet Unsupervised Learning Supervised Learning Breast Cancer

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

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

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

Adoption of Solar Pumping Systems by Vegetable Farmers in Niayes Agro-Ecological Zone of Senegal: Adoption as a Sequential Process

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Power and Energy Engineering 2024年第9期12卷 19-36页

作者： Abou Abdoulaye Sow Papa Yona boubacar Mane Mamma Sawaneh Halidou Kafando Department of Agriculture and Environment Science University of The Gambia Kanifing The Gambia Department of Economic and Management Sciences Gaston Berger University Saint-Louis Senegal

This article examines the determinants of the adoption of solar pumping systems (PV) by vegetable farmers in the Niayes area of Senegal. To measure the determinants, we used a sequential logit model to translate the adoption process from becoming aware of solar pumping systems to testing them, i.e. using them at least once, and then continuing to use them over time. The results show that the main variables affecting awareness of the use of solar pumping systems (PV) are age, marital status, experience, access to credit, the farmer’s knowledge of climate change, the farmer’s origin in the Thiès region and length of time in the Niayes area. The first use of PVs is influenced by factors such as the size of the plot, the distance of the plot from the main road or from the market. Finally, the decision to adopt or continue use is influenced by gender, experience, household size and access to credit. Surprisingly, access to credit does not affect the first use of solar pumping systems, but plays a key role in their continued use.

关键词： Solar Pumping Systems Adoption Vegetable Cultivation Niayes (Senegal)

Trends of Land Use and Land Cover Change in the Savannah Ecological of the Protected Area Reserve Partielle de Dosso, Niger

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Natural Resources 2024年第3期15卷 61-68页

作者： Amadou Issoufou Abdourhimou Moussa boubacar Habou Rabiou Soumana Idrissa Mahamane Ali Faculté des Sciences Agronomiques Université de Diffa Diffa Niger Institut National de la Recherche Agronomique du Niger Niamey Niger Faculté des Sciences et Techniques Université Abdou Moumouni de Niamey Niamey Niger

Information on the dynamics of savannah is important to a country's plan to overcome the problems of uncontrolled development and environmental hazards. Taking the reserve partielle de Dosso, Niger as the case study area, this paper analyzed the long-term land use land cover change from 2002 to 2022. Satellite images were processed by using Google Earth Engine (GEE). Therefore, four major land cover classes were identified based on spectral characteristics of Land sat, namely, built-up, vegetation, cropland, bare land and water. The result revealed that barren and built-up areas increased at the expense of vegetation and water. From the four major land use land cover the large area is covered by vegetation which comprises about 192963.5 hectares followed by cropland and water consisting of 32506.43 and 1596.4 hectares respectively. The built-up area gained substantial area (most) during the study period. The reduction in some of the land cover/uses underlines the dangerous trend of the pressure poised by population growth and the changing functionality. Land cover change is influenced by a variety of societal factors operating on several spatial and temporal levels. The area estimates and spatial distributions of the LULC classes produced from the current study will assist local authorities, managers, and other stakeholders in decision-making and planning regarding forest land cover and uses.

关键词： Land Use/Cover Change Detection Classification Dosso

Splenectomy: Indications in the General Surgery Department of Ignace Deen Hospital

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Surgical Science 2024年第4期15卷 219-224页

作者： Mamadou Sakoba Barry boubacar Barry Sandaly Diakité Aboubacar Touré Aissatou Taran Diallo General Surgery Department Ignace Deen National Hospital at Conakry University Hospital Conakry Guinea Faculty of Health Sciences and Technology Gamal Abdel Nasser University of Conakry Conakry Guinea

Introduction: Splenectomy is the surgical removal of the spleen. It can be performed during various pathologies, ranging from abdominal trauma to hemoglobinopathies. The progress made in the knowledge of the immune functions of the spleen and the fear of post-splenectomy infectious complications have favored the development of surgical or non-surgical splenic preservation techniques calling into question the dogma of splenectomy. The aim of this study was to determine the indications for splenectomy. Methodology: This was a retrospective, descriptive study lasting 5 years in the general surgery department of the Ignace Deen National Hospital. All files of splenectomized patients were included, our variables were clinical, therapeutic and progressive. Results: We collected 42 cases of splenectomies out of the 2478 surgical procedures performed, representing 1.7% of the department’s surgical activities. The average age was 44 years. The age group of 41 to 50 years was the most represented, i.e. 26% (n = 11) of cases. Sex ratio = 1. Abdominal pain was the reason for consultation in patients, i.e. 100% (n = 42) of cases. The antecedents were dominated by recurrent malaria with 52.3% (n = 22) of cases, then recurrent anemia in 21% (n = 9), and 16.7% (n = 7) had sickle cell disease. Splenomegaly was found in 31 patients, or 73.6%. Ultrasound was performed in all patients. The indications for splenectomy were: isolated splenomegaly with risk of rupture (38%, n = 16), hypersplenism (26%, n = 11) and trauma to the spleen (19.04%, n = 8). Total splenectomy was performed in all cases. The surgical consequences were favorable in 85.7%, (n = 36) with morbidity of 14% (n = 6) and mortality of 9.52% (n = 4). The average length of hospitalization was 10.4 days with extremes of 1 and 22 days. Conclusion: Splenectomy constitutes a relatively common surgical procedure in our context. The indications for splenectomy were isolated splenomegaly with risk of rupture, hypersplenism and tra

关键词： Splenectomy Indications Ignace Deen

Spatio-Temporal Dynamics of Land Use Units in the Kadzel Sub-Catchment Basin in Diffa, Niger

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Geographic Information System 2024年第4期16卷 259-275页

作者： Karema Ary Madou Kaoulé Moussa Mamoudou boubacar Amadou Issoufou Abdorhimou Mahamane Ali Faculty of Agronomic Sciences University of Diffa Diffa Niger Faculty of Science and Technology Abdou Moumouni University of Niamey Niamey Niger

Environmental degradation linked to land occupation and use, such as climate change and anthropogenic activities, has led to the modification of the landscape units of the Kadzel sub-watershed. The objective of this study is to analyze the dynamics of land use units in the Kadzel area in Diffa between 1992 and 2022 and to propose a future scenario for sustainable environmental management. The approach used relies on remote sensing and geographic information systems to analyze the dynamics of land use units. Additionally, the Markov Cellular Automata (CA) model was used to predict future land use. The land cover maps were produced from a supervised classification by maximum likelihood based on the true and false color compositions of bands 4/3/2 (TM5), 3/2/1 (ETM+) and 7/5/4 (8 OLI). Ten occupation classes were discriminated. Between 1992 and 2022, there was a decrease in the areas of irrigated crops (4.91% and 2.88%), of shrubby tree steppes (14.31% and 9.48%), field-fallow complexes (22.23% and 10.52%), and degraded areas. Grassy steppes (25.76% and 13.32%). However, this reduction has been beneficial for wastelands, urban areas and bodies of water. Based on predictive modeling, it is predicted that by 2052, urban areas, fallow field complexes and bare soils will constitute the main types of housing units. The regressive trend in natural resources appears to continue into the future with current land use practices.

关键词： Occupation Dynamics Environmental Problems Population Growth Lake Chad and Kadzel Basin

Ruptured Ectopic Pregnancy: Epidemiology and Management in the General Surgery Department of the Ignace Deen National Hospital, Conakry University Hospital

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Obstetrics and Gynecology 2024年第4期14卷 503-508页

作者： Barry Mamadou Sakoba Barry boubacar Guirassy Mariam Touré Aboubacar Diallo Aissatou Taran Department of General Surgery Ignace Deen National Hospital/Conakry University Hospital Conakry Guinea Faculty of Health Sciences and Technology Gamal Abdel Nasser University of Conakry Conakry Guinea

Introduction: The aim of this study was to contribute to improving the quality of GEUR management in the general surgery department and in the maternity ward of the Ignace Deen national hospital, Conakry University Hospital. Methodology: This was a retrospective, descriptive study lasting two years (January 1, 2020 to December 31, 2022), carried out in the general surgery and gyneco-obstetrics departments of the Ignace Deen national hospital, Conakry University Hospital. We included all patients with a ruptured ectopic pregnancy who received surgical treatment during the study period. Results: We collected 13,524 cases of surgical interventions in the two services, among them, we recorded 89 cases or 0.66% GEUR. The average age of the patients was 24.26 years. Brides were the most represented with 80.96% of cases. Women practicing a liberal profession were 51.69% (n = 46) and housewives 26.97% (n = 24). Clinically, amenorrhea was noted in all patients, i.e. 100%, abdominal-pelvic pain in 95.2% (n = 85) of cases, metrorrhagia in 94.08% (n = 84), abdominal-pelvic sensitivity in 97.44% (n = 87) of cases and anemia in 85.39% of cases. The GEUR was ampullary in 69.66% (n = 62) cases. Salpingectomy was performed in 90.72% (n = 81). The surgical outcomes were satisfactory in 98.87% (n = 88) of cases. We recorded one case of surgical site infection. We have not recorded any deaths. The average length of hospitalization was 4 days. Conclusion: GEUR is relatively high in our context. A good understanding of the prognostic factors of GEUR, awareness and family planning could reduce GEUR.

关键词： Ruptured Ectopic Pregnancy Epidemiology and Management

Corrective Effect of the Angle of Incidence of the Magnetic Field Intensity on the Performance (Series and Shunt Resistances) of a Bifacial Silicon Solar Cell

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Energy and Power Engineering 2024年第9期16卷 313-323页

作者： Idrissa Sourabié Mahamadi Savadogo boubacar Soro Ramatou Saré Christian Zoundi Martial Zoungrana Issa Zerbo Laboratoire de Chimie Analytique de Physique Spatiale et nergtique (L@CAPSE) Ecole Doctorale Sciences et Technologies Universit Norbert ZONGO Koudougou Burkina Faso Laboratoire dEnergies Thermiques Renouvelables (L.E.T.RE) Ecole Doctorale Sciences et Technologies Universit Joseph KI-ZERBO Ouagadougou Burkina Faso

This article presents a three-dimensional analysis of the impact of the angle of incidence of the magnetic field intensity on the electrical performance (series resistance, shunt resistance) of a bifacial polycrystalline silicon solar cell. The cell is illuminated simultaneously from both sides. The continuity equation for the excess minority carriers is solved at the emitter and at the depth of the base respectively. The analytical expressions for photocurrent density, photovoltage, series resistance and shunt resistance were deduced. Using these expressions, the values of the series and shunt resistances were extracted for different values of the angle of incidence of the magnetic field intensity. The study shows that as the angle of incidence increases, the slopes of the minority carrier density for the two modes of operation of the solar cell decrease. This is explained by a drop in the accumulation of carriers in the area close to the junction due to the fact that the Lorentz force is unable to drive the carriers towards the lateral surfaces due to the weak action of the magnetic field, which tends to cancel out as the incidence angle increases, and consequently a drop in the open circuit photovoltage. This, in turn, reduces the Lorentz force. These results predict that the p-n junction of the solar cell will not heat up. The study also showed a decrease in series resistance as the incidence angle of the magnetic field intensity increased from 0 rad to π/2 rad and an increase in shunt resistance as the incidence angle increased. His behaviour of the electrical parameters when the angle of incidence of the field from 0 rad to π/2 rad shows that the decreasing magnetic field vector tends to be collinear with the electron trajectory. This allows them to cross the junction and participate in the external current. The best orientation for the Lorentz force is zero, in which case the carriers can move easily towards the junction.

关键词： Angle of Incidence Magnetic Field Intensity Bifacial Polycrystalline Silicon Solar Cell Series Resistance Shunt Resistance