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2. A Retrospective Single Centre Analysis of the Incidence of Hospital Admission for Acute Coronary Syndrome During the COVID-19 Pandemic

Author

Nadim Shah, Naser J.S. Jamil, Geili Abdalla, Khalifa O Muhammed, Haitham A.R. Al Hashimi, and Fahad O. Baslaib

Subjects
General Medicine
Abstract

Background: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a pandemic due to ‘coronavirus disease 2019’ (COVID-19) that has led to millions of deaths. This may have resulted in a change in the rate of admissions for other potentially life-threatening conditions such as acute coronary syndromes (ACS). Therefore, we investigated the incidence of ACS admissions during the current pandemic and compared it to a similar period the year before. Methods: This was a retrospective analysis of all patients admitted to a tertiary cardiology centre with ACS between February 2019 and the end of April 2019 (pre-COVID) that was compared with admissions between the same three months in 2020 (post-COVID). The main outcomes of interest were to evaluate any potential reduction of ACS admissions during the pandemic or change in mortality. In addition, we evaluated the rate of patients proceeding to coronary angiography (CAG). Results: During the post-COVID period, only 200 patients were admitted with ACS as compared to 331 patients during the pre-COVID period (39.6% reduction; 95% confidence interval (CI): 34% - 44%; p Conclusion: There was a significant reduction in admissions for ACS in the post-COVID period compared to a similar period prior. There was also a reduction in the overall invasive management of ACS, with less CAG performed but no associated reduction in the rate of PPCI. The in-hospital mortality rate was similar in the two groups.

Published
2023

7. Green communication in 6G

Author

Hoque, M., primary, Farhad, S. S. B., additional, Dewanjee, S., additional, Alom, Z., additional, Mokhtar, R. A., additional, Saeed, R. A., additional, Khalifa, O. O., additional, Ali, E. S., additional, and Abdul Azim, M., additional

Published
2022
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21. The transfer of construction management technology to developing countries - Libya as a case study

Author

Metawa, Khalifa O.

Subjects
658, developing countries, improvement, performance, personnel, productivity, technology transfer, economic development, Libya
Abstract

This thesis aims to highlight the issue of improving the productivity of the construction industry in developing countries at a macro-level, through the adoption of technology transfer, with the intention of identifying the basic organizational variables that determine and/or strongly affect the national construction productivity, and to formulate a practical approach for their improvement. Following an outline of the aims and methods of the study, firstly, the evolution of ideas on socio-economic development are considered to show the need of each country to a specific industrial development strategy, based on its own resources and peculiar conditions. This is followed by a discussion of the evidence related to the planning strategies for construction development, and their contribution to the growth of the national economies of both developed and developing countries. Generally, they suggest that the construction industry in developing countries had contributed less than its counterpart in developed countries, and therefore, it should be expanded and organized more efficiently. Organization of construction is next considered, with emphasis placed upon the nature of the industry and the contribution of the existing organizational strategies to its development. In reviewing the current construction management approaches of both developing and developed countries, the similarity between their diagnosis of the problems and prescriptions for their improvement are analysed and crystallised into a theoretical framework for further discussion. In order to test the model, a historical view of the Libya's industry is presented, comparing its early development within the suggested measures. The performance of each aspect of the model is evaluated within the criteria suggested by socio-economic and organization theories eg. the extent to which the established objectives are met. Generally, the evidence indicates that over two decades of their application, Libya has not achieved the planned targets. It is observed that, in addition to the influence of the local general environmental forces, there are certain other technical, structural, personnel technological and managerial factors underlying construction productivity improvement. The need for a practical strategy is emphasised. A programme for its implementation is formulated.

Published
1987

22. May Measurement Month 2018: a pragmatic global screening campaign to raise awareness of blood pressure by the International Society of Hypertension

Author

Beaney, Thomas, Burrell, Louise M, Castillo, Rafael R, Charchar, Fadi J, Cro, Suzie, Damasceno, Albertino, Kruger, Ruan, Nilsson, Peter M, Prabhakaran, Dorairaj, Ramirez, Agustin J, Schlaich, Markus P, Schutte, Aletta E, Tomaszewski, Maciej, Touyz, Rhian, Wang, Ji-Guang, Weber, Michael A, Poulter, Neil R, Burazeri, Genc, Qirjako, Gentiana, Roshi, Enver, Cunashi, Rudina, Fernandes, Mario J C C, Victória Pereira, Savarino S, Neto, Marisa F M P, Oliveira, Pombalino N M, Feijão, Ana C G, Cerniello, Yamila, Marin, Marcos J, Garcia Vasquez, Fortunato, Espeche, Walter G, Stisman, Diego, Fuentes, Inés A, Zilberman, Juith M, Rodriguez, Pablo, Babinyan, Kamsar Yu, Engibaryan, Anna H, Avagyan, Avag M, Minasyan, Arsen A, Gevorkyan, Ani T, Carnagarin, Revathy, Carrington, Melinda J, Sharman, James E, Lee, Rebecca, Perl, Sabine, Niederl, Ella, Malik, Fazila-Tun-Nesa, Choudhury, Sohel R, Al Mamun, Mohammad A, Ishraquzzaman, Mir, Anthony, Fiona, Connell, Kenneth, De Backer, Tine L M, Krzesinski, Jea, Houenassi, Martin D, Houehanou, Corine Y, Sokolovic, Sekib, Bahtijarevic, Rankica, Tiro, Mary B, Mosepele, Mosepele, Masupe, Tiny K, Barroso, Weimar S, Gomes, Marco A M, Feitosa, Audes D M, Brandão, Andrea A, Miranda, Roberto D, Azevedo, Vanda M A A, Dias, Luis M, Garcia, Glenda D N, Martins, Idiana P P, Dzudie, Anastase, Kingue, Samuel, Djomou, Florent A N, Njume, Epie, Khan, Nadia, Lanas, Fernando T, Garcia, Maria S, Paccot, Melanie F, Torres, Pamela I, Li, Yan, Liu, Min, Xu, Liying, Li, Li, Chen, Xin, Deng, Junping, Zhao, Wenwu, Fu, Lingjuan, Zhou, Yi, Lopez-Jaramillo, Patricio, Otero, Johanna, Camacho, Paul A, Accini, Jose L, Sanchez, Gregorio, Arcos, Edgar, M’Buyamba-Kabangu, Jean-René, Katamba, Fortunat K, Ngoyi, Georges N, Buila, Nathan M, Bayauli, Pascal M, Ellenga Mbolla, Bertrand F, Bakekolo, Paterne R, Kouala Landa, Christian M, Kimbally Kaky, Gisele S, Kramoh, Euloge K, Ngoran, Yves N K, Olsen, Michael H, Valdez Valoy, Laura, Santillan, Marcos, Angel Rafael, Gonzalez Medina, Peñaherrera, Carlos E, Villalba, Jose, Ramirez, Maria I, Arteaga, Fabricio, Delgado, Patricia, Beistline, Holly, Cappuccio, Francesco P, Keitley, James, Tay, Tricia, Goshu, Dejuma Y, Kassie, Desalew M, Gebru, Sintayehu A, Pathak, Atul, Denolle, Thierry, Tsinamdzgvrishvili, Bezhan, Trapaidze, Dali, Sturua, Lela, Abesadze, Tamar, Grdzelidze, Nino, Grabfelder, Mark, Krämer, Bernhard K, Schmeider, Roland E, Twumasi-Ankrah, Betty, Tannor, Elliot K, Lincoln, Mary D, Deku, Enoch M, Wyss Quintana, Fernando S, Kenerson, John, Jean Baptiste, Emmanuela D, Saintilmond, Wideline W, Barrientos, Ana L, Peiger, Briggitte, Lagos, Ashley R, Forgas, Marcelo A, Lee, Vivian W Y, Tomlinson, Brian W Y, Járai, Zoltán, Páll, Dénes, More, Arun, Maheshwari, Anuj, Verma, Narsingh, Sharma, Meenakshi, Mukherjee, Tapan K, Patil, Mansi, Pulikkottil Jose, Arun, Takalkar, Anant, Turana, Yuda, Widyantoro, Bambang, Danny, Siska S, Djono, Suhar, Handari, Saskia D, Tambunan, Marihot, Tiksnadi, Badai B, Hermiawaty, Eka, Tavassoli, Elham, Zolfaghari, Mahsa, Dolan, Eamon, O'Brien, Eoin, Borghi, Claudio, Ferri, Claudio, Torlasco, Camilla, Parati, Gianfranco, Nwokocha, Chukwuemeka R, Nwokocha, Magdalene I, Ogola, Elijah N, Gitura, Bernard M, Barasa, Anders L, Barasa, Felix A, Wairagu, Anne W, Nalwa, Wafula Z, Najem, Robert N, Abu Alfa, Ali K, Fageh, Hatem A, Msalam, Omar M, Derbi, Hawa A, Bettamar, Kzaki A, Zakauskiene, Urte, Vickiene, Alvita, Calmes, Jessica, Alkerwi, Ala'a, Gantenbein, Manon, Ndhlovu, Henry L L, Masiye, Jones K, Chirwa, Maureen L, Nyirenda, Nancy M, Dhlamini, Tiyezge D, Chia, Yook C, Ching, Siew M, Devaraj, Navin K, Ouane, Nouhoum, Fane, Tidiani, Kowlessur, Sudhir, Ori, Bhooshun, Heecharan, Jaysing, Alcocer, Luis, Chavez, Adolfo, Ruiz, Griselda, Espinosa, Cutberto, Gomez-Alvarez, Enrique, Neupane, Dinesh, Bhattarai, Harikrishna, Ranabhat, Kamal, Adhikari, Tara B, Koirala, Sweta, Toure, Ibrahim A, Soumana, Kabirou H, Wahab, Kolawole W, Omotoso, Ayodele B, Sani, Mahmoud U, Okubadejo, Njideka U, Nadar, Sunil K, Al-Riyami, Hassan A, Ishaq, Mohammad, Memon, Feroz, Sidique, Sualat, Choudhry, Hafeez A, Khan, Rasheed A, Ayala, Myrian, Maidana, Angel J O, Bogado, Graciela GG, Ona, Deborah I, Atilano, Alberto, Granada, Carmela, Bartolome, Regina, Manese, Loudes, Mina, Arnold, Dumlao, Maria C, Villaruel, Mariyln C, Gomez, lynn, Jóźwiak, Jacek, Małyszko, Jolanta, Banach, Maciej, Mastej, Mirosław, de Carvalho Rodrigues, Manuel M, Martins, Luis L, Paval, Alexandra, Dorobantu, Maria, Konradi, Alexandra O, Chazova, Irina E, Rotar, Oxana, Spoares, Miryan C, Viegas, Deolsanik, Almustafa, Bader A, Alshurafa, Saleh A, Brady, Adrian, Bovet, Pascal, Viswanathan, Bharathi, Oladapo, Olulola O, Russell, James W, Brguljan-Hitij, Jana, Bozic, Nina, Knez, Judita, Dolenc, Primoz, Hassan, Mohammed M, Woodiwiss, Angela J, Myburgh, Caitlynd, Vally, Muhammed, Ruilope, Luis M, Molinero, Ana, Rodilla, Enrique, Gijón-Conde, Teresa, Beheiry, Hind M, Ali, I A, Osman, Asma A A, fahal, Naiema A W, Osman, Hana A, Altahir, Fatima, Persson, Margaretha, Wuerzner, Gregoire, Burkard, Thilo, Wang, Tzung-Dau, Lin, Hung-Ju, Pan, Heng-Yu, Chen, Wen-Jone, Lin, Eric, Mondo, Charles K, Ingabire, Prossie M, Khomazyuk, Tatyana TA, Krotova, Viktoriia V-Yu, Negresku, Elena, Evstigneeva, Olena, Bazargani, Nooshin NB, Agrawal, Amrish, Bin Belaila, Buthaina A, Suhail, Aisha M, Muhammed, Khalifa O, Shuri, Hassan H, Wainford, Richard D, Levy, Philip D, Boggia, José JG, Garré, Laura L, Hernandez-Hernandez, Rafael, Octavio-Seijas, Jose A, Lopez-Rivera, Jesus A, Morr, Igor, Duin, Amanda, Huynh, Minh V, Cao, Sinh T, Nguyen, Viet L, To, Muoi, Phan, Hung N, Cockroft, John, McDonnell, Barry, Goma, Fastone M, Syatalimi, Charity, Chifamba, Jephat, Gwini, Rudo, Tiburcio, Osiris Valdez, Xia, Xin, 20035632 - Kruger, Ruan, 10922180 - Schutte, Aletta Elisabeth, Beaney T., Burrell L.M., Castillo R.R., Charchar F.J., Cro S., Damasceno A., Kruger R., Nilsson P.M., Prabhakaran D., Ramirez A.J., Schlaich M.P., Schutte A.E., Tomaszewski M., Touyz R., Wang J.-G., Weber M.A., Poulter N.R., and Borghi C

Subjects
Male, Cardiac & Cardiovascular Systems, Cross-sectional study, Blood Pressure, 030204 cardiovascular system & hematology, Global Burden of Disease, 0302 clinical medicine, Surveys and Questionnaires, MMM Investigators, Mass Screening, 030212 general & internal medicine, 1102 Cardiorespiratory Medicine and Haematology, Antihypertensive medication, RISK, Global, Awareness, Middle Aged, PREVALENCE, Hypertension, Blood pressure, Screening, Raised blood pressure, Female, Cardiology and Cardiovascular Medicine, BURDEN, Life Sciences & Biomedicine, Control, Adult, medicine.medical_specialty, Fast Track Clinical Research, Opportunistic Sampling, 03 medical and health sciences, Internal medicine, medicine, SYSTEMATIC ANALYSIS, MANAGEMENT, Humans, Mass screening, Disease burden, Antihypertensive Agents, Science & Technology, business.industry, Case-control study, Blood Pressure Determination, Treatment, Editor's Choice, RAMADAN, Cross-Sectional Studies, Cardiovascular System & Hematology, Case-Control Studies, Cardiovascular System & Cardiology, business, Hypertension, Blood pressure, Screening, Global, Treatment, Control
Abstract

Aims Raised blood pressure (BP) is the biggest contributor to mortality and disease burden worldwide and fewer than half of those with hypertension are aware of it. May Measurement Month (MMM) is a global campaign set up in 2017, to raise awareness of high BP and as a pragmatic solution to a lack of formal screening worldwide. The 2018 campaign was expanded, aiming to include more participants and countries. Methods and results Eighty-nine countries participated in MMM 2018. Volunteers (≥18 years) were recruited through opportunistic sampling at a variety of screening sites. Each participant had three BP measurements and completed a questionnaire on demographic, lifestyle, and environmental factors. Hypertension was defined as a systolic BP ≥140 mmHg or diastolic BP ≥90 mmHg, or taking antihypertensive medication. In total, 74.9% of screenees provided three BP readings. Multiple imputation using chained equations was used to impute missing readings. 1 504 963 individuals (mean age 45.3 years; 52.4% female) were screened. After multiple imputation, 502 079 (33.4%) individuals had hypertension, of whom 59.5% were aware of their diagnosis and 55.3% were taking antihypertensive medication. Of those on medication, 60.0% were controlled and of all hypertensives, 33.2% were controlled. We detected 224 285 individuals with untreated hypertension and 111 214 individuals with inadequately treated (systolic BP ≥ 140 mmHg or diastolic BP ≥ 90 mmHg) hypertension. Conclusion May Measurement Month expanded significantly compared with 2017, including more participants in more countries. The campaign identified over 335 000 adults with untreated or inadequately treated hypertension. In the absence of systematic screening programmes, MMM was effective at raising awareness at least among these individuals at risk.

Published
2019

23. Deep learning for environmentally robust speech recognition.

Author

Alhamada, A. I., Khalifa, O. O., Abdalla, A. H., Shariffudin, Shafinaz Sobihana, Herman, Sukreen Hana, and Hashim, Hashimah

Subjects
*DEEP learning, *SPEECH perception, *CONVOLUTIONAL neural networks, *AUTOMATIC speech recognition, *ARTIFICIAL intelligence
Abstract

Deep learning is an emerging technology that is one of the most promising areas of artificial intelligence. Great strides have been made in recent years which resulted in increased efficiency with regards to many applications, including speech. Despite this, an environmentally Robust Speech Recognition system is still far from being achieved. In this article, an investigation of previous work has been conducted. The use of deep learning in speech recognition was analyzed and a proper deep learning architecture was identified. A method using convolutional neural network (CNN) is used with the aim of enhancing the performance of speech recognition systems (SRS). This study found that this CNN-based approach achieves a 94.32% validated accuracy [ABSTRACT FROM AUTHOR]

Published
2020
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25. Selection criteria for resuscitation and survivability rates for neonates at the limit of viability.

Author

Salama, H., Al Rifai, H., Mahmoud, N., Al Qubasi, M., Al Obaidly, S., Sabry, I., Ben Hadj Khalifa, O., Mousa, A., and Sabouni, A.

Subjects
NEWBORN infants, RESUSCITATION, DEATH rate, GESTATIONAL age, NEONATOLOGISTS
Abstract

AIM: To evaluate outcomes of a cohort of infants born at 23 weeks' gestational age after introducing a new selection score for resuscitation in the delivery room (DR). METHODS: This was a retrospective charts review study using data from the maternal and newborn registry funded by the Qatar National Research Fund. Parents were consulted prenatally and their wishes were honored. The plan of resuscitation was based on the new selection score. The seven components of the score were four antenatal and three immediate postnatal in the DR. Each component received a score of zero, one, or two according to its presence, uncertainty or absence, respectively. Only a score of≥7 would receive active resuscitation unless specified otherwise during prenatal consultation. RESULTS: The study reviewed 60 infants that were delivered over a two year period. The DR death rate was 23 of 60 (38%). Thirty-seven infants (61%) were admitted to the NICU. The score was applied only on 37 infants where all score criteria were reported in their files. Twenty infants had score <7; of them 13 (65%) died in the DR and 7 were admitted to NICU of whom two (29%) survived to discharge. Seventeen babies with scores≥7 admitted to NICU of whom nine (51%) survived to discharge. The survival rate to discharge was 13 of 37(35%). A satisfaction survey included 33 neonatal physicians; 32 neonatologists stated the score was easy to comprehend, 26 voted for easy to implement, and 30 voted for ethical relief and moral comfort. CONCLUSIONS: Using a resuscitation score of seven was associated with improved survival until the discharge of those infants resuscitated. NICU physicians described the score as functional and convenient. [ABSTRACT FROM AUTHOR]

Published
2020
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26. Solutions Globales Régulières pour Quelques Équations Lineaires D'évolution du Type Pseudo-Différentiel Singulier

Author

Gourdin, D., Kamoun, H., and Ben Khalifa, O.

Subjects
Linear Cauchy Problem, Integral Kirchhof Solutions, Global Solution, Sobolev Spaces
Abstract

We give here examples of equations of type (1) ∂tt2 y -p(t, Dx) y = 0, where p is a singular pseudo-differential operator with regular global solutions when the Cauchy data are regular, t ∈ R, x ∈ R5., 2000 Mathematics Subject Classification: 35C15, 35D05, 35D10, 35S10, 35S99.

Published
2016

29. Establishing the change in antibiotic resistance of Enterococcus faecium strains isolated from Dutch broilers by logistic regression and survival analysis

Author

Stegeman, J A, Vernooij, J C M, Khalifa, O A, Van den Broek, J, Mevius, D J, LS GZ Landbouwhuisdieren, LS Theoretische Epidemiologie, LS Klinisch Onderzoek Wagenaar, LS GZ Landbouwhuisdieren, LS Theoretische Epidemiologie, and LS Klinisch Onderzoek Wagenaar

Subjects
animal origin, Veterinary medicine, antibiotic resistance, Enterococcus faecium, Colony Count, Microbial, Logistic regression, Virginiamycin, susceptibility, Poultry, survival analysis, Food Animals, Reference Values, Odds Ratio, CIDC - Divisie Bacteriologie en TSE's, bacteria, Cecum, Netherlands, biology, Hazard ratio, denmark, Anti-Bacterial Agents, Erythromycin, surveillance, Sample collection, Abattoirs, medicine.drug, trends, Monitoring, Microbial Sensitivity Tests, growth promotion, Drug Resistance, Bacterial, medicine, Animals, antimicrobial resistance, Gram-Positive Bacterial Infections, Poultry Diseases, Survival analysis, Proportional Hazards Models, business.industry, food, Odds ratio, biology.organism_classification, Survival Analysis, agents, Biotechnology, Logistic Models, Animal Science and Zoology, business, Chickens
Abstract

In this study, we investigated the change in the resistance of Enterococcus faecium strains isolated from Dutch broilers against erythromycin and virginiamycin in 1998, 1999 and 2001 by logistic regression analysis and survival analysis. The E. faecium strains were isolated from caecal samples that had been randomly collected from six slaughterhouses. Moreover, between the sample collection in 1998 and the sample collection in 1999, virginiamycin and the macrolide antibiotics (of which erythromycin is a member) have been banned in The Netherlands from use in broiler feeds as growth promoter. In the logistic regression analysis we used the internationally accepted cut-off values to determine whether bacteria were resistant or not. In the survival analysis, inhibition of bacterial growth was the event and time to event was replaced by concentration of antibiotic to event. As a consequence, changes in the growth of bacteria can be tested over an entire range of concentrations and no cut-off value for resistance has to be determined. We performed the survival analysis by use of a Cox logistic model with an odds ratio (OR) for the increase of the odds of the basic hazard rate as outcome. Both the logistic regression and the survival analyses showed that resistance to erythromycin and virginiamycin decreased during the study period. In the logistic regression model the ORs associated with the fraction of bacteria inhibited by the antibiotics in 2001 as compared to 1998 were 3.76 (2.57–5.49) for erythromycin and 11.65 (7.68–17.66) for virginiamycin. The corresponding ORs from the survival analysis were lower; 2.88 (2.21–3.76) and 2.11 (1.80–2.49), respectively. The reason for the differences between the ORs of the survival analysis and the logistic regression analysis is probably because most changes in resistance included the cut-off value and logistic regression specifically examines those changes.

Published
2006

34. Prolonged corrected QT interval in hospitalized patients with coronavirus disease 2019 in Dubai, United Arab Emirates: a single-center, retrospective study

Author

Sameera Mohamed Ali, Anas Musa, Khalifa Omar Muhammed, Sumbul Javed, Mohamed Al Raqabani, Basem Adnan Baradie, Marian Sobhi Gargousa, Oghowan AbdelRahman Osman, Salah AlDeen Roqia, Jeyaseelan Lakshmanan, Haitham Al Hashemi, and Fahad Omar Baslaib

Subjects
Medicine (General), R5-920
Abstract

Objective To evaluate the association of a prolonged corrected QT (QTc) interval in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and its association with in-patient mortality. Methods A cohort of 745 patients were recruited from a single center between 1 March 2020 and 31 May 2020. We analyzed the factors associated with a prolonged QTc and mortality. Results A prolonged QTc interval >450 ms was found in 27% of patients admitted with SARS-CoV-2 infection. These patients were predominantly older, on a ventilator, and had hypertension, diabetes mellitus, or ischemic heart disease. They also had high troponin and D-dimer concentrations. A prolonged QTc interval had a significant association with the requirement of ventilator support and was associated with an increased odds of mortality. Patients who died were older than 55 years, and had high troponin, D-dimer, creatinine, procalcitonin, and ferritin concentrations, a high white blood cell count, and abnormal potassium concentrations (hypo- or hyperkalemia). Conclusions A prolonged QTc interval is common in patients with SARS-CoV-2 infection and it is associated with worse outcomes. Older individuals and those with comorbidities should have an electrocardiogram performed, which is noninvasive and easily available, on admission to hospital to identify high-risk patients.

Published
2021
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36. Establishing the change in antibiotic resistance of Enterococcus facium strains isolated from Dutch broilers by logistic regression and survival analysis

Author

LS GZ Landbouwhuisdieren, LS Theoretische Epidemiologie, LS Klinisch Onderzoek Wagenaar, Stegeman, J A, Vernooij, J C M, Khalifa, O A, Van den Broek, J, Mevius, D J, LS GZ Landbouwhuisdieren, LS Theoretische Epidemiologie, LS Klinisch Onderzoek Wagenaar, Stegeman, J A, Vernooij, J C M, Khalifa, O A, Van den Broek, J, and Mevius, D J

Published
2006

40. P324 - Un syndrome peut en cacher un autre

Author

Ben Hadj Khalifa, O., primary, Pervillé, A., additional, De Saint Martin, A., additional, Laugel, V., additional, De Sèze, C., additional, Dollfus, H., additional, Hirsch, E., additional, and Fischbach, M., additional

Published
2010
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42. Contribution à la propagation de la marée en Loire

Author

Khalifa, O. A., Thomas, Pierre, Riou, Yvon, Institut de Recherche en Génie Civil et Mécanique (GeM), Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), and Université de Nantes (UN)-Université de Nantes (UN)-École Centrale de Nantes (ECN)-Centre National de la Recherche Scientifique (CNRS)

Subjects
River, Loire, [SPI.GCIV]Engineering Sciences [physics]/Civil Engineering, propagation, tide, fleuve, [SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology, marée
Abstract

International audience; The remarkable increase in the tonnage of ships sailing up the River Loire to supply the ports of Saint-Nazaire, Montoir, Donges. Cordemais and Nantes has resulted in higher costs for channel maintenance, owing to the regular dredging operations required. Significant savings on dredging costs can be made by optimizing ship movement in accordance with the tide. A Channeling Application Program modeling the flows and ship movements has been devised to simulate ship paths. lt soon became obvious that the accuracy of the Channelling Application Program depended on water height prediction in the channel. A comparative study on tide observation at five stations located between Saint-Nazaire and Nantes and on tide prediction by the harmonic analysis method at these points was undertaken. This revealed the influence of the river flow rate and stressed the need to quantify prediction inaccuracy. A correction methodology is suggested here and is currently being put into practice; L'accroissement sensible du tonnage des navires remontant la Loire pour desservir les ports de Saint-Nazaire, Montoir, Donges, Cordemais et Nantes entraîne les surcoûts d'entretien du chenal inhérents aux régulières opérations de dragages. L'objectif de cette étude est de tirer le meilleur parti de ce phénomène périodique et naturel qu'est la marée, qui peut engendrer des variations de hauteur supérieures à 6 mètres. Pour y parvenir, il faut d'abord pouvoir établir une prédiction du phénomène, c'est à dire connaître à tout instant la hauteur dans le chenal. Il faut ensuite mettre au point un modèle hydraulique de chenalage permettant de calculer en tout lieu la hauteur d'eau sous la quille d'un navire donné se déplaçant dans le chenal.Pour cela, nous avons développé différents codes de calculs permettant la prédiction de la marée et la simulation des mouvements de navires dans le chenal intérieur de la Loire. Il s'est rapidement avéré que la précision du programme de chenalage dépend en grande partie de celle de la méthode de prédiction. Nous avons alors particulièrement mis l'accent sur la confrontation expérimentale des hauteurs d'eau prédites et mesurées en cinq stations réparties sur le chenal entre Saint-Nazaire et Nantes, grâce à un réseau de télémarégraphes. Dans cette étude, qui fait suite aux travaux de Paul (1986) et Riou (1987), nous avons cherché à quantifier ces imprécisions et à mettre en évidence les effets des perturbations atmosphériques sur la marée en Loire. Nous avons en particulier isolé l'effet du débit fluvial amont sur la prédictionentre Nantes et Saint-Nazaire. Ceci nous a permis de dégager une méthodologie de travail qui devra sensiblement améliorer les résultats de la prédiction, et par là ceux du chenalage.

Published
1993

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