Unimodular-Upper polynomial matrix decomposition for MIMO Spatial Multiplexing

International audienceWe present a simple algorithm to compute the factors of a Unimodular-Upper (UU) polynomial matrix decomposition. The algorithm relies on the classical LU factorization and the inverse of the unimodular factor is also provided. Such decomposition is useful for spatial multiplexing in MIMO channel transmission system since it enables to reduce the MIMO channel matrix into independent SISO channels by a pre- and post-filtering. Unlike the classical QR-based polynomial matrix Singular Values Decomposition (QR-PMSVD), the proposed UU method allows to completely cancel the co-channel interference (CCI). Moreover, most of the resulting independent SISO channels are likely to be reduced to simple additive noise channels, i.e. with no InterSymbol Interference. However, the noise is coloured and possibly enhanced due to the non unitary property of the corresponding post filter. The complexity and sum rate capacity performance of the proposed method are studied and compared with QR-PMSVD.Nous présentons un algorithme simple de décomposition d'une matrice polynômiale comme le produit d'une matrice unimodulaire et d'une matrice polynomiale triangulaire supérieur. L'algorithme repose sur la factorisation LU classique et l'inverse du facteur unimodulaire est également fourni. Une telle décomposition est utile pour un multiplexage spatial dans un système de transmission sur un canal MIMO convolutif, car elle permet de réduire ce dernier en des canaux SISO indépendants par un pré- et post-filtrage. Contrairement à la décomposition SVD classique à base de factorisation QR (QR-PMSVD), la méthode proposée ici permet d'annuler complètement l'interférence inter-canal (CCI). En outre, la plupart des canaux SISO résultants après pré- et post-filtrage sont vraisemblablement réduits à des canaux simples à bruit additif, c'est à dire sans interférence intersymbole. En l'occurrence, la fonction de transfert du premier canal réduit est une constante si, et seulement si, l'ensemble des polynômes formant la première colonne et la première ligne du canal MIMO original est irréductible. Cependant, les pré- et post filtres n'étant pas parauniitaires, le bruit résultant est coloré voire amplifié. La complexité et les performances en termes de débit global sont étudiées et comparées avec celles obtenues avec la décomposition QR-PMSVD

Maternal and perinatal outcomes in multiple versus singleton pregnancies in Dakar, Senegal: a cross sectional study over 10 years

Background: The birth of twins is a singular event in most societies, and even more when it comes to multiple births. The objective of this study was to investigate maternal and perinatal outcomes in multiple versus singleton pregnancies.Methods: Cross-sectional study carried out at Philippe Maguilen Senghor health center in Dakar, Senegal from January 1, 2011 to June 30, 2019. Data were extracted from this E-perinatal electronic database and then analyzed in statistical package for social science software (SPSS 24, Mac version).Results: A total 42,870 mothers delivered 44,149 newborns including 1250 twins (2.8%) and 29 triplets. The mean maternal age was 27 years. Mothers with multiple pregnancies had 3 times the odds of poor maternal outcome compared to mothers with single pregnancies (OR 2.42, 95% CI; 1.98-2.94, p <0.001, for high blood pressure; OR, 2.66; 95% CI, 2.11-3.32, p= <0.001, for severe pre-eclampsia; and OR, 3.04; 95% CI, 1.64-5.66, p <0.001, for postpartum hemorrhage). Likewise, women with multiple gestations had significantly higher rates of preterm birth (OR 5.62; 95% CI: 4.91-6.41, p <0.001), breech presentations (OR = 11.02; CI = 9.68-12.53, p <0.001) and neonatal deaths (OR = 2.94; CI = 9.6852-12.5328 p= 0.004) as compared to women with singleton gestations. Furthermore, women with multifetal gestations had increased risk for caesarean section (OR 2.14; 95% CI: 1.91-2.41, p <0.001) compared with their singleton counterparts. The risks for episiotomy and perineal injuries were higher for women with singleton gestations as compared to multiple gestation mothers.Conclusions: This study results are in line with previous findings and contradict others. Particular attention should always be paid to multiple pregnancies’ management. However, the pattern of certain complications traditionally correlated with multiple pregnancies is to be confirmed

Le cactus Opuntia tuna (L.) Mill. et ses formes d’usage dans la zone des Niayes au Sénégal

Opuntia tuna est une espèce bien adaptée dans la zone des Niayes au Sénégal. Sa prolifération assez rapide est due en partie à une sous exploitation suscitant ainsi un envahissement de quelques espaces agropastoraux. Dans une perspective de valorisation et de meilleure gestion de l’espèce, cette présente étude a été conduite pour comprendre les formes d’usages et de gestion de la plante par les populations locales afin de la promouvoir pour renforcer leur résilience. L’étude a porté sur cinq villages de la zone nord des Niayes auprès de petits exploitants de maraichers. Des enquêtes qualitatives par entretiens et groupes de discussion ont été conduites. Elles ont porté sur le niveau de connaissance, les pratiques et usages connus du cactus, les contraintes liées à sa présence, les solutions adoptées ou envisagées et le niveau de perception sur sa valorisation. Les résultats ont révélé de nombreux usages de la plante et de ses produits. Plus de la moitié des personnes enquêtées utilise le cactus dans le domaine agricole. L’élevage, la pharmacopée et l’alimentation sont d’autres secteurs également concernés par l’usage du cactus. Les analyses ont montré que la plupart des personnes enquêtées (94%) admettent un degré d’envahissement très élevé de Opuntia tuna. Le niveau d’envahissement pourrait être liée à la zoochorie selon 38% des hommes et 33% des femmes. La bonne adaptation de l’espèce dans la zone serait également un facteur de prolifération selon 33% des hommes et 23 % des femmes. Afin de pallier la prolifération rapide du cactus les maraichers ont développé des stratégies de gestion telles que le brulis, la coupe et le dessouchage. Une meilleure gestion de cette espèce qui présente de nombreux usages pour les maraichers de la zone des Niayes est nécessaire. De tels usages de l’espèce, valorisés davantage pourrait contribuer de façon significative à la diversification des sources de revenus des communautés locales et au développement durable de la zone des Niayes

Migration of intrauterine device into the pelvic cavity: exploration strategy and management in African environment

IUD migration is a rare complication. We report our experience in the treatment of five cases of uterine perforation and migration of IUDs. The average age of patients was 34.6 years, an average parity was 4. All patients felt an unusual pain during insertion of the IUD Tcu 380A. The location of the IUD was done through ultrasound and hysterography. Removal by laparoscopy was performed in all cases. The immediate impacts of the surgery were simple. Hysterography has its place in the location of the migrated IUD. Prevention is a good IUD insertion technique

Completeness of information in electronic compared with paper-based patients’ records in a maternity setting in Dakar, Senegal

Background: Evaluate the consistency of information in paper-based records when registered in parallel with an electronic medical record.Methods: The study was performed at PMSHC in Dakar Senegal. From the end of year 2016, patients’ files were recorded on both paper-based and electronically. Additionally, previous records were electronically registered. To investigate the completeness of records before and after the electronic recording system has been implemented, information about some maternal and fetal/neonatal characteristics were assessed. When the variable was recorded, the system returned 1, unrecorded variables were coded as 0. We then calculated, for each variable, the unrecorded rate before 2017 and after that date. The study period extended from 2011 to June 2019, a nearly ten-year period. Data were extracted from E-perinatal to MS excel 2019 then SPSS 25 software. Frequencies of unrecorded variables were compared with chi-squared test at a level of significance of 5%.Results: A total of 48,270 unique patients’ records were identified during the eight-year period.  Among the study population, data for patients’ age, address and parity were available most of the time before and after 2017 (0.5% missing data versus 0.3% for age and 2.6% versus 1.3% for home address and from 0.3% to 0.0% for parity). However, phone number, maternal weight, maternal height, last menstrual period and blood group were found to be missing up to 96% before 2017. From 2017, these rates experienced a sudden decrease at a significant level: from 82.4% to 27.8% for phone number, from 96% to 56.3% for maternal weight and from 60.1% to 21.3% for blood group. Regarding newborns’ data, it was found that fetal height, head circumference and chest circumference were missing up to just under 25% before 2017. After that date, their completeness improved and flattened under 5%.Conclusions: Structured and computerized files reduce missing data. There is an urgent need the Ministry of health provides hospitals and health care providers with guidelines that describes the standardized information that should be gathered and shared in health and care records

Laparoscopic management of cervical and endometrial cancer in Africa: experience of the National Hospital Centre of Pikine

Background: Laparotomy represents the standard historical surgical approach to these cancers. Process of treatment of benign adnexal pathologies to the emergence of a new pathway for the management of these cancerous pathologies.Methods: Our prospective study from December 2016 to December 2018 included 10 patients with early-stage uterine cancer and endometrial cancer confirmed by MRI. The characteristics of patients, their cancer, their intervention and morbidity were revealed.Results: Our results show that the average age of the patients was 63 years; There were 2 cases of cervical cancer and 8 cases of endometrial cancer. For cervical cancer, it was essentially squamous cell carcinoma; one patient was at stage Ia2 and the other at stage Ib1. For endometrial cancers, squamous cell carcinoma was 80%; 6 patients were in stage IB and 2 in stage IC. Of the 10 patients undergoing surgery, 9 had laparoscopic colpohysterectomy and lymphadectomy and one complementary laparoscopic lymphadenectomy. The average number of lymph nodes removed was 9 and no lymph node metastasis was found. In the immediate postoperative period, one patient had transient urinary incontinence and another had vaginal slice lymphorhea.Conclusions: The main interest of this practice is to be the least morbid possible for patients at the early stage. With our short experience, we obtained a reduction in operating time, a reduction in hospital stay, a decrease in the consumption of analgesics and antibiotics postoperatively and a reduction in per and postoperative complications

Tuberculose intestinale révélée par une occlusion intestinale aigüe au cours d’une réaction paradoxale au traitement anti-tuberculeux chez un patient immunocompétent: à propos d’un cas et revue de la littérature

La tuberculose intestinale représente 3 à 5% de toutes les localisations viscérales. Malgré l'efficacité démontrée des anti-tuberculeux, des cas d'exacerbation du tableau clinique initial ont été décrits à l'initiation du traitement. Ces réactions dites «paradoxales» sont cependant rarement rapportées chez les immunocompétents et beaucoup moins sous forme d'occlusion intestinale. Nous rapportons un cas de tuberculose intestinale révélée par une occlusion intestinale aigüe au cours d'une réaction paradoxale aux anti-tuberculeux. Il s'agit d'un patient de 26 ans, immunocompétent qui a présenté un syndrome occlusif à un mois de traitement d'une tuberculose pleuro-pulmonaire. La tomodensitométrie (TDM) abdominale était en faveur d'une occlusion intestinale grêlique. La laparotomie objectivait une masse intra-péritonéale avec de multiples adhérences. L'examen anatomopathologique de la pièce opératoire était en faveur d'une tuberculose intestinale. L'évolution était favorable après la poursuite du traitement anti-tuberculeux initial

Predictability of intra-seasonal descriptors of rainy season over Senegal using global SST patterns

Seasonal forecasting of the rainfall characteristics in Sahel is of crucial interest in determining crop variability in these countries. This study aims to provide further characterization of nine rainfall metrics over Senegal (Onset, cessation, LRS, CDD, CDD7, CDD15, NR90p, NR95p, NR99p)and their response to global SST patterns from 1981 to 2018. The Climate Hazards Group InfraRed Precipitation with Station (CHIRPS) dataset and the Hadley Centre Global Sea Ice and Sea Surface Temperature (HadISST) were used. The results showed strong spatio-temporal variability with a pronounced south–north gradient for all metrics. The earliest onset was observed in the south of the country from 4 July and the latest onset in the north from 9 August. Since 2012, a new regime is observed with an increase in both long dry spells and extreme wet events. Furthermore, SST forcing has shown that the North tropical Atlantic and the East Equatorial Pacific are better able to explain the interannual variability of the intraseasonal descriptors. However, the prediction of metrics is earlier for the most remote basin (Pacific) compared to the most local basin (Atlantic). These results have implications for the seasonal forecasting of Sahel’s intraseasonal variability based on SST predictors, as significant predictability is found far from the beginning of the season

Facteurs associés à la dissociation immunovirologique chez les patients infectés par le VIH-1 sous traitement antirétroviral hautement actif au Centre de Traitement Ambulatoire (CTA) de Dakar

Introduction: L'objectif de ce travail était d'évaluer les différents facteurs associés à la dissociation immunovirologique malgré un traitement antirétroviral hautement actif et efficace.Méthodes: Il s'agissait d'une étude de cohorte historique, descriptive et analytique faite à partir de dossiers de patients infectés par le VIH-1; sous traitement antirétroviral depuis au moins 12 mois, suivis dans la cohorte du CTA de 2001 à 2011 et ayant une charge virale indétectable depuis 6 mois.Résultats: Durant cette période d'étude de 10 ans, la prévalence de la DIV était de 19,3%. Le sexe féminin était prédominant avec un sexe ratio de 1,9. La dissociation immunovirologique a été plus fréquemment rencontrée chez les patients de sexe masculin (29,7% vs 14,1%) avec une différence statistiquement significative (p = 0,00006). L'âge médian était de 44 ans ± 10 ans. Un antécédent de tuberculose a été retrouvé dans environ un tiers des cas (31,4%). La dissociation immunovirologique était significativement plus fréquente chez les patients ayant un antécédent de tuberculose (p = 0,00005). La plupart des patients (68%) était au stade SIDA 3 ou 4 de l'OMS. Les patients ayant une dissociation immunovirologique étaient plus souvent aux stades 3 et 4 de l'OMS (p = 0,0001). La dénutrition a été notée dans plus de la moitié des cas (56,2%) et la dissociation immunovirologique prédominait chez les patients dénutris (p=0,005). Le taux moyen de lymphocytes TCD4+ était de 86,7± 83 cellules / mm3. La dissociation immunovirologique était plus fréquente chez les patients ayant un taux de lymphocytes TCD4 bas à l'initiation avec une différence statistiquement significative (p = 0,00000). En analyse multivariée; Seuls l'âge supérieur ou égal à 43 ans, le taux de CD4 initial &lt; 100 c/mm3 et le sexe masculin étaient significativement associés à cette dissociation immunovirologique.Conclusion: Les principaux facteurs associés à la dissociation immunovirologique étant évalués, d'autres études portant sur ce groupe mériteraient d'être envisagées afin de connaitre l'impact de cette réponse immunologique partielle sur la survenue d'infections opportunistes ou bien la mise en place d'une trithérapie spécifique uniquement dans le but d'avoir une restauration immunologique optimale.Mots clés: Dissociation, immunovirologique, VIH, DakarEnglish Title: Factors associated with immunovirologic dissociation in HIV-1-infected patients under highly active antiretroviral therapy in the Ambulatory Treatment Center (ATC) in DakarEnglish AbstractIntroduction: the objective of this work is to evaluate the different factors associated with immunovirologic dissociation despite highly active and effective antiretroviral treatment.Methods: we conducted a retrospective, cohort, descriptive and analytical study of the medical records of HIV-1 infected patients having received at least 12 months of antiretroviral therapy, followed in the ATC cohort from 2001 to 2011 and with undetectable viral load in the last 6 months.Results: during this 10-year study period, the prevalence of IVD was 19.3%. Female sex was predominant, with a sex ratio of 1.9. Immunovirologic dissociation was more frequent in male patients (29.7% vs 14.1%) with a statistically significant difference (p = 0,00006). The average age was 44 years ± 10 years. A history of tuberculosis was found in about a third of the cases (31.4%). Immunovirologic dissociation was significantly more frequent in patients with a history of tuberculosis (p = 0.00005). Most patients (68%) had AIDS at WHO clinical stages 3 or 4. Patients with immunovirologic dissociation were more often in WHO clinical stages 3 and 4 (p = 0.0001). More than half of the cases (56.2%) were found to be malnourished and immunovirologic dissociation was prevalent in malnourished patients (p=0.005). The mean CD4+ T lymphocytes counts was 86.7± 83 cells / mm3. Immunovirologic dissociation was more frequent in patients with initial low CD4+ T lymphocyte counts and with a statistically significant difference (p = 0.00000). By multivariate analysis, only age greater than or equal to 43 years, CD4 initial counts &lt; 100 c/mm3 and male sex were significantly associated with this immunovirologic dissociation.Conclusion: our study assessed the main factors associated with immunovirologic dissociation. Other studies of this nature would also merit consideration in order to highlight the impact of this partial immune response on the emergence of opportunistic infections or the implementation of a specific tritherapy for the sole purpose of producing fully successful immune restoration.Keywords: Dissociation, immunovirologic, HIV, Daka

Spatial and temporal dynamics of West Nile virus between Africa and Europe

It is unclear whether West Nile virus (WNV) circulates between Africa and Europe, despite numerous studies supporting an African origin and high transmission in Europe. We integrated genomic data with geographic observations and phylogenetic and phylogeographic inferences to uncover the spatial and temporal viral dynamics of WNV between these two continents. We focused our analysis towards WNV lineages 1 (L1) and 2 (L2), the most spatially widespread and pathogenic WNV lineages. Our study shows a Northern-Western African origin of L1, with back-and-forth exchanges between West Africa and Southern-Western Europe; and a Southern African origin of L2, with one main introduction from South Africa to Europe, and no back introductions observed. We also noticed a potential overlap between L1 and L2 Eastern and Western phylogeography and two Afro-Palearctic bird migratory flyways. Future studies linking avian and mosquito species susceptibility, migratory connectivity patterns, and phylogeographic inference are suggested to elucidate the dynamics of emerging viruse