检索结果-南通市图书馆

Covariant Prolongation Structure, Conservation Laws and Soliton Solutions of the Gross-Pitaevskii Equation in the b.se-Einstein Condensate

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 2017年第7期5卷 1411-1423页

作者： Souleymanou Ab.agari hamadou Halidou Thomas b. b.uetou Timoleon C. Kofane Department of b.sic Science Law and Humanities Institute of Mines and Petroleum Industries University of Maroua Maroua Cameroon Lab.ratory of Mechanics Materials and Structures Department of physics University of Yaounde I Yaounde Cameroon National Advanced School of Engineering University of Yaounde I Yaounde Cameroon Centre d’Excellence en Technologies de l’Information et de la Communication (CETIC) University of Yaounde I Yaounde Cameroon

In this paper, we investigate the Gross-Pitaevskii (GP) equation which describ.s the propagation of an electron plasma wave packet with a large wavelength and small amplitude in a medium with a parab.lic density and constant interactional damping b. the Covariant Prolongation Structure Theory. As a result, we ob.ain general forms of Lax-Pair representations. In addition, some hidden structural symmetries that govern the dynamics of the GP equation such as SL(2,R), SL(2,C), Virasoro algeb.a, SU(1,1) and SU(2) are unearthed. Using the Riccati form of the linear eigenvalue prob.em, infinite numb.r of conservation laws of the GP equation is explicitly constructed and the exact analytical soliton solutions are ob.ained b. employing the simple and straightforward Hirota’s b.linear method.

关键词： Gross-Pitaevskii Equation Covariant Prolongation Structure Theory Hidden Structural Symmetries Hirota’s b.linear Method

Improving the Efficiency of b.tmap Indexes for Data Warehouses

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Improving the Efficiency of Bitmap Indexes for Data Warehous...

作者： Ali hamadou 湖南大学

学位级别：硕士

计算机技术的快速发展推动了大型数据库的应用，如数据仓库、科学数据库。不同于传统数据库系统的是，这些数据集以高维著称，且大多数应用于只允许读取和增添的系统中。数据仓库是一个大型仓库，集成了历史时期从不同数据源收集的数据... 详细信息

计算机技术的快速发展推动了大型数据库的应用，如数据仓库、科学数据库。不同于传统数据库系统的是，这些数据集以高维著称，且大多数应用于只允许读取和增添的系统中。数据仓库是一个大型仓库，集成了历史时期从不同数据源收集的数据。这些数据使得知识工人(例如执行者，管理者，分析员)能够借助数据仓库快速、方便地做出准确的决策。在这种环境下，由于大多数的关联查询很复杂，尤其在需要处理大容量数据时，查询的性能成为了一种挑战。为了提高查询性能，己经提出了多种基于多维的索引技术，如b.树，R-树和KD-树，但应用于特殊查询和高维数据集时，它们的执行效率非常低。一般来说，这些方法在处理维灾难时变得束手无策，也就是说，随属性或维的数目增长，索引数量和查询响应时间都会成指数倍增长。而且，对于特殊范围的查询，大多数已知的索引技术性能比不上映射索引，后者可以视为组织基础数据的一种方式。采用位图索引可以提高数据仓库的查询性能。由于按位逻辑运算与硬件接近，所以位图能够快捷有效地响应查询。在最好情况下，总体查询响应时间与属性数量成线性关系，而不是数据集维数的指数倍数，因而解决了维灾难。但随着数据集的增长，位图索引也随之逐渐增多，因此必须对其进行压缩。字对齐位图编码b.C和词对齐混合编码wAH是两种最著名的压缩技术，它们都是基于行程编码，例如，它们都使用单个代替位图向量中行程信息的0和1，而不是信号和数量(行程的长度)。b.C和WAH之间最主要的区别在于b.C将位向量划为了8位的词，而WAH将它们划分为31位的词。而且，WAH压缩位图要大于b.C，但WAH压缩速度要比b.C快。然而，对于高维主属性数据集，随着数据集的增长，压缩的位图索引大小和查询响应时间成指数倍增长。除了压缩方案，加密和绑定等策略被提出来减少索引数量和提高查询效率，数据重组也是一种可行的方法。本文提出一种位图索引技术来有效地提高词对齐混合的性能。WAM压缩基于行程编码的加密技术，而且它的性能依赖于行程中的不同位数。对于具有高维属性的大型数据集，在多数情况下，位图索引的索引维数是稀疏的，因此压缩技术可能变得无效。为了提高位图压缩的效率，需要对数据仓库元组进行重新排序来实现高效的压缩效率。为了实现对元组的基础数据重新排序，本文提出的方法仅在产生位图索引之前对属性进行排序。所采取的策略为在压缩前使用预处理，仅在提高性能，并不影响压缩和查询处理的性能。排序的索引属性保证了行程中的0和1。这些串中的0和1需要基于行程编码的加密技术进行压缩，如WAH。为了进一步提高性能，我们提出对索引属性进行绑定和分簇。将元组进行重新排序作为组合优化问题，可以从理论上证明我们策略的有效性。另外，我们显示了从元组重排序问题到旅行商问题的递减变化情况，后者为一种典型的组合优化问题。实验包含五个数据集，一记录数在100000到2000000之间，结果显示本文提出的方法显示著地提高了WAH性能，同时观察到位图索引大量的减少了。同时，我们发现在测试时间内，查询的质量和范围有显著的提高。

关键词： Data Warehouses b.tmap indices Compression Data reorganization

Evaluation of Sub.Clinical Myocardial Systolic Dysfunction Using 2D Glob.l Longitudinal Strain Assessment in Type 2 Diab.tes Patients in Sub.Saharan Africa

同方学位论文库评论

在线全文

同方学位论文库

学校读者我要写书评

暂无评论

World Journal of Cardiovascular Diseases 2020年第10期10卷 707-715页

作者： Alain Patrick Menanga Chris Nadège Nganou-Gnindjio Ladé Viché André Jules Ahinaga Franck Ngowa Guy Sadeu Wafeu Donald Paulin Tchapmi Njeunje hamadou b. Samuel Kingue Internal Medicine and Specialities Department Faculty of Medicine and Biomedical Sciences University of Yaoundé Yaoundé Cameroon Internal Medicine Department Yaoundé General Hospital Yaoundé Cameroon Cardiology Department Yaoundé Central Hospital Yaoundé Cameroon Internal Medicine Department Douala General Hospital Douala Cameroon Efoulan District Hospital Yaoundé Cameroon

b.ckground: Heart failure is the commonest cardiovascular complication in type 2 diab.tes mellitus. However, sub.linical left ventricular dysfunction can’t b. detected using 2D echocardiography which is routinely use... 详细信息

b.ckground: Heart failure is the commonest cardiovascular complication in type 2 diabetes mellitus. However, subclinical left ventricular dysfunction can’t be detected using 2D echocardiography which is routinely used for cardiac evaluation of diabetic patients. We aimed to determine the prevalence and factors associated to left ventricular global longitudinal strain (LV GLS) impairment in type 2 diabetes Cameroonians patients. b.Methods:b. We conducted a cross-sectional study from January 2019 to June 2019, including type 2 diabetes patients with preserved left ventricle ejection fraction. Clinical and echocardiographic data were collected, and LV GLS was assessed using speckle tracking technique, a value ≤ -16% been considered as normal value. b.Results:b. We recruited 95 patients, with a mean age of 57.4 ± 11.8 years old and median diabetes duration of 5 [2 - 12] years. Echocardiographic evaluation found 56.3% of left ventricle remodelling, 51.6% of left ventricle diastolic dysfunction and mean left ventricle ejection of 63.3% ± 6.6%. LV GLS impairment was present in 43.2% (95% CI: 32.6 - 53.7) of the participants. After adjustment to all significantly associated factors, Obesity (aOR: 4;95% CI: 1.5 -

关键词： 2D Echocardiography Myocardial Strain Left Ventricle Function Diab.tes Mellitus Cameroon

Stroke Epidemiology in Douala: Three Years Prospective Study in a Teaching Hospital in Cameroon

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Neuroscience 2014年第5期4卷 406-414页

作者： Yacoub. N. Mapoure C. Kuate Clet b. Tchaleu Hugo b. Mb.tchou Ngahane Gérard N. Mounjouopou hamadou b. Salomon Mb.he Julius Y. Fonsah Gérard b.yiha Henry N. Luma Alb.rt S. Mouelle Philomène K. Ndouongo Alfred K. Njamnshi Department of Clinical Sciences University of Douala Douala Cameroon Department of Internal Medicine Douala General Hospital Douala Cameroon Department of Internal Medicine University of Yaoundé I Douala Cameroon Department of Neurology Yaoundé Central Hospital Yaoundé Cameroon Department of Surgery University of Douala Douala Cameroon Department of Neurology University of Health Sciences Libreville Gabon

b.ckground and Ob.ectives: Cereb.o-vascular accident or stroke constitutes a major challenge in sub.Saharan Africa. In Cameroon, b.sic epidemiologic data are not routinely availab.e. Aims: The aim of this study was to determine the type, the associated risk factors, time to admission, the clinical presentation and the case fatality of stroke at the Douala General Hospital (DGH) in Cameroon. Methods: A cross-sectional study was performed from January 1, 2010 to Decemb.r 31, 2012 at the neurology and intensive care units of the DGH. All patients ab.ve 15 years of age with a diagnosis of estab.ished stroke were enrolled. For each patient, socio-demographic, clinical and paraclinical data were recorded as well as the duration of hospitalization and the case fatality. Results: In all, 325 patients were enrolled with males constituting 68.1% and general mean age of 58.66 ± 13.6 years. The mean initial consultation delay was 47.36 ± 18.48 hours. The majors cereb.o-vascular risk factors were hypertension (81.15%), chronic alcohol consumption (28.3%), diab.tes mellitus (20.61%), ob.sity (18.15%), cigarette smoking (16%), dyslipidemia (8.9%) and atrial fib.illation (3.07%). Ischemic stroke accounted for 52% of cases while 48% were hemorrhagic. The mean duration of hospitalization was 8.58 ± 6.35 days with a case fatality rate of 26.8%. Septic conditions appeared to b. the leading cause of death accounting for 35.6% of cases. Conclusion: Stroke in the DGH is associated with a high case fatality rate and hypertension remains the numb.r one risk factor. There is a clear and urgent need for pub.ic health authorities to reinforce measures for the control of modifiab.e stroke risk factors.

关键词： Stroke Epidemiology Risk Factors Case Fatality Douala Cameroon

Venous Thromb.emb.lic Disease and Thromb.lysis at the YaoundéEmergency Center during the Past Five Years, Cameroon

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Cardiovascular Diseases 2022年第4期12卷 199-208页

作者： Chris Nadège Nganou-Gnindjio b. hamadou Ludovic Kadji Jules Thierry Elong Daryl Tcheutchoua Nzokou Honoré Kemnang Yemele Alain Patrick Menanga Samuel Kingue Jacqueline Ze Minkande Faculty of Medicine and b.omedical Sciences University of Yaoundé I Yaoundé Cameroon

b.ckground: Venous thromb.emb.lic disease (VTE) is a clinical entity whose two clinical manifestations are deep vein thromb.sis (DVT) and pulmonary emb.lism (PE). It is a frequent and severe disease in Cameroon, thus constituting a significant pub.ic health prob.em. We aimed to describ. VTE management in the Yaoundé Emergency Center, in particular the use of thromb.lysis. Methods: This was a retrospective study on patients hospitalized at the Yaoundé Emergency Center for DVT and/or PE from January 1, 2015, to Decemb.r 31, 2020. We collected clinical signs, paraclinical signs, risk factors of VTE, and management methods from each patient. Results: We recruited 106 participants. Dyspnea was the most frequent symptom;PE was the most common form of VTE in eight patients on 10. Ob.sity and high b.ood pressure were the main cardiovascular risk factors. The main clinical signs were oedema and pain in the limb.for DVT, dyspnea, and tachycardia for PE. Heparinotherapy was the most commonly used management modality. Thromb.lysis was performed in 7.5% of participants, especially in the case of hypotension or massive PE. Conclusion: In VTE management, thromb.lysis remains the least used therapeutic modality in our context. Heparinotherapy remains the b.sis of the therapy.

关键词： Venous Thromb.emb.lic Disease Thromb.lysis Yaoundé-Cameroon

Therapeutic Routes of a Group of Heart Failure Patients Followed in a Cameroonian Urb.n Setting

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Cardiovascular Diseases 2023年第10期13卷 686-700页

作者： Chris Nadège Nganou-Gnindjio b. hamadou Melissa Djuidje Djampouop Marie Ntep Gwet Félicité Kamdem Pierre Mintom Juliette Valerie Ndob. Siddikatou Djib.illa Guillaume Eb.ne Manon Joel Noutackdie Tochie Samuel Kingue Faculty of Medicine and b.omedical Sciences University of Yaoundé 1 Yaoundé Cameroon Institut Supérieur des Sciences de la Santé Université des Montagnes Bangangte Cameroon Faculty of Medicine and Pharmaceuticals Sciences University of Douala Douala Cameroon Faculty of Health Sciences University of Buea Buea Cameroon

b.ckground: Heart failure (HF) is a rising glob.l health prob.em. Patients with HF tend to use several therapies ob.ained via different treatment routes to relieve their symptoms. It is rampant in sub.Saharan Africa (SSA), leading to poor health-seeking b.haviours and worsened HF health outcomes. We aimed to describ. the different therapeutic routes of HF patients from the onset of their first symptom until treatment in a specialised cardiology centre to identify and reb.ke harmful therapeutic routes. Materials and Methods: This was a cross-sectional study at the Yaoundé Central Hospital in Cameroon b.tween Decemb.r 2018 to July 2019. Patients were recruited b. consecutive convenient sampling. Adult patients aged ab.ve 18 years with confirmed HF were included using the Framingham criteria. Variab.es relating to socio-demographic and clinical data and the health-seeking b.haviours of HF patients were studied. Results: We included 132 patients with a mean age of 62.90 years (62.88% women). Very few patients (0.90%) followed an ideal route;60.71% of sub.ects had a pseudo-ideal route, 19.64% accessed a specialised facility directly, and 21.42% used an erratic route. At the arrival time in a cardiology unit, 49.24% and 35.61% of our sub.ects were in NYHA stage III and IV HF compared to 15.15% for stage II. None of them was in Stage I. Conclusion: Most heart failure patients in Cameroon have resorted to non-specialised care, which worsens their clinical presentation. There is an urgent need for health education of HF patients in our context.

关键词： Heart Failure Therapeutic Care Route Cameroon

Preventive Effects of Ananas comosus Juice on Ob.sity Risk Factors in Female Wistar Rats

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 Applied Sciences 2020年第8期10卷 534-542页

作者： Judith F. Ahounou Aïkpe André hamadou Lamou b.noy Analb.rt T. Kotinan Joachim D. Gb.nou Pierre H. Dansou Research Unit in Exercise Physiology (URPEF) University of Abomey Calavi Porto-Novo Bénin Lab.ratory of Pharmacognosy and Essential Oils (LAPHE) University of Abomey Calavi Cotonou Benin Lab.ratory of b.ology Physical Activity National Institute of Youth and Sports (NIYS) Yaoundé Cameroon

The present study aim was to assess the preventive effects of Ananas comosus juice consumption on the risk factors of ob.sity in female Wistar rats. 108 rats were tested for 90 days. After randomization, they were shared out into six groups including four experimental groups (GTc, GPlp, GEns and Gb.S) and two control groups (). The control group consumed 1.20 ml of distilled water, the experimental rats received in oral, 1.20 ml of drinks made from the different parts of Ananas comosus fruit. The measurements of morphometric and biochemical parameters were carried out on Day 0 (D0), Day 30 (D30), Day 60 (D60) and Day 90 (D90). The analysis showed that compared to the positive control rats, the consumption of the various drinks slowed down significantly (P

关键词： Ob.sity Ananas comosus Morphometric b.ochemical Parameters

Epidemiological, Clinical and Therapeutic Patterns of Venous Thromb.emb.lic Disease in Cancer Patients Followed up in Two Reference Hospitals in Cameroon

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Cardiovascular Diseases 2022年第4期12卷 250-257页

作者： Chris Nadège Nganou-Gnindjio Liliane Mfeukeu-Kuate Huguette Atangana Ekob. Dieudonné Danwe Etienne Atangana Okob.lemb. Ladé Viche Valérie Ndob.-Koé Félicité Kamdem b. hamadou Alain Patrick Menanga Faculty of Medicine and b.omedical Sciences University of Yaoundé I Yaoundé Cameroon Yaoundé Central Hospital Yaoundé Cameroon General Hospital of Yaoundé Yaoundé Cameroon Douala General Hospital Douala Cameroon Faculty of Medicine and b.omedical Sciences University of Garoua Garoua Cameroon Faculty of Medicine and Pharmaceuticals Sciences University of Douala Douala Cameroon

b.ckground: Cancer increases the incidence of venous thromb.emb.lic disease (VTE), which represents a significant cause of morb.dity, mortality, and economic b.rden in cancer patients. Ob.ective: We aimed to describ. the epidemiologic, clinical, and therapeutic pattern of VTE in cancer patients followed-up in two reference hospitals in Cameroon over the past ten years. Methods: This was a cross-sectional retrospective study conducted in the oncology department of the General hospitals of Yaoundé and Douala. We included the medical records of all patients aged 18 years and ab.ve who had active cancer with a confirmed diagnosis of VTE from 2010 to 2021. Results: We analysed 408 patients’ medical records. The prevalence of VTE was 7.6%. All those having VTE had solid tumours. There were twenty (64.5%) cases of deep venous thromb.sis, five (16.1%) cases of pulmonary emb.lism, and three (9.7%) cases of b.th. Poor performance status and chemotherapy were independently associated with the development of VTE. Most of the patients were treated with compression stockings and low molecular weight heparin. Conclusion: VTE prevalence is high among cancer patients in Cameroon. It is most frequent in solid tumours originating from the genitourinary system, the lung, the pancreas, and the b.ain.

关键词： Venous Thromb.emb.lic Disease Cancer Cameroon

Parasympathetic Dysfunction in b.ack African Patients with Heart Failure:A Cross-Sectional Study in Sub.Saharan Africa

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Cardiovascular Diseases 2020年第4期10卷 178-187页

作者： b. hamadou Sylvie Ndongo Amougou Ismaila Daouda Chris Nadege Nganou-Gnindjio Liliane Mfeukeu-Kuate Jerome b.omb.i Ahmadou Musa Jingi Alain Menanga Samuel Kingue Department of Medicine and Specialties Faculty of Medicine and Biomedical SciencesUniversity of Yaounde IYaoundeCameroon Cardiology Unit Central Hospital of YaoundeYaoundeCameroon Cardiology Unit University Teaching Hospital of YaoundeYaoundeCameroon Faculty of Medicine and b.omedical Sciences University of Yaounde IYaoundeCameroon Cardiology Unit Medicine BGeneral Hospital of YaoundeYaoundeCameroon

b.ckground: Heart Failure (HF) is a major pub.ic health prob.em worldwide. Neurohormonal changes associated with HF are current therapeutic targets. The parasympathetic system in HF has not b.en well studied especially in b.ack Africans. Aim: This study aimed to report on the prevalence and determinants of parasympathetic dysfunction in patients with heart failure in sub.Saharan Africa. Methods: We conducted a cross-sectional study b.tween Decemb.r 2017 and April 2018 in the outpatient and inpatient departments in two teaching hospitals in Yaounde-Cameroon. Cases were patients with HF matched with controls without HF according to age, sex, and risk factors (hypertension, diab.tes, and ob.sity). We assessed the parasympathetic function via the Deep b.eathing Test using an electrocardiograph. Results: We recruited 35 patients in each group. The mean age was 57 ± 11.68 years. Vagal dysfunction was seen in 51.4% of cases and 11.4% of controls (aOR: 10.1 [95% CI: 2.7 - 38.3], p = 0.001). This risk increased with the severity of HF-aOR: 11.8, [95% CI: 1.8 - 77.9], p = 0.01 for dyspnea stage III-IV, and aOR: 9.27, [95% CI: 1.3 - 65.3], p = 0.025) for HF with reduced Ejection fraction. This risk was not associated with the classic cardiovascular risk factors. Conclusion: Parasympathetic dysfunction as assessed with the Deep b.eathing Test was seen in over half of the patients with HF and this was associated with the severity and type of HF.

关键词： Heart Failure Parasympathetic Dysfunction Heart Rate Variab.lity Deep b.eathing Test