Spatial and temporal distribution of North Atlantic tropical cyclones

The aim of this work is to provide a classification of tropical cyclones (TC) according to their location, month of genesis and their lifecycles and to study the role of African Easterly Waves (AEWs) in North Atlantic cyclogenesis. Between 1980 and 2004, 269 tropical cyclones (TCs) were formed over the North Atlantic, 77% of which occurred during the August-October period and 95% of major hurricanes (TCs in which the maximum sustained wind was greater or equal to 50 m/s) were generated in the same period. The high activity of the August-October period was due to the favourable thermodynamic and dynamic conditions that simultaneously exist over the main development region (MDR). A classification of TCs according to their months of genesis and lifecycles showed that TCs generated before August and after October have no preferential latitude and longitude of genesis. TCs generated at the East of 60°W and over the southern part of the MDR have long lifecycles. Major hurricanes have long lifecycles and are generally initiated over the southern part of the MDR and East of 60°W. The spatial representation of the cyclogenesis area shows that cyclones are generated along two main axes; one is situated around 12.5°N (southern axis) and the second around 27.5°N (northern axis). 56% (44%) of TCs are generated over the southern axis (northern axis). 92% of TCs initiated along the southern axis originate from African Easterly Waves. While 64% of those generated over the northern axis are linked to mid-latitude baroclinic systems and upper level cold lows. This study contributes to a better understanding of North Atlantic cyclogenesis characteristics as well as the role of AEWs

The Contribution Of Increased Aerobic Capacity And Stride Length Alteration To Increased Physical Work Capacity

The purposes of this study were (1) to examine the contribution of physiological adaptation versus stride length adaptation to increased physical work capacity after an 11 week aerobic training program for beginning runners, and (2) to determine if males and females responded differently to the variables tested

The Effects Of Stereotyped And Nonstereotyped Literature On Children's Achievement-Motivation

Sixty preschool age and sixty second graders were used as subjects to determine the effects of sex-stereotyped and non-sex-stereotyped literature on children's achievement-motivation

21st century research in urban WASH and health in sub-Saharan Africa: methods and outcomes in transition

Tackling global inequalities in access to Water, Sanitation and Hygiene (WASH) remains an urgent issue - 58% of annual diarrhoeal deaths are caused by inadequate WASH provision. A global context of increasing urbanisation, changing demographics and health transitions demands an understanding and impact of WASH on a broad set of health outcomes. We examine the literature, in terms of health outcomes, considering WASH access and interventions in urban sub-Saharan Africa from 2000 to 2017. Our review of studies which evaluate the effectiveness of specific WASH interventions, reveals an emphasis of WASH research on acute communicable diseases, particularly diarrhoeal diseases. In contrast, chronic communicable and non-communicable health outcomes were notable gaps in the literature as well as a lack of focus on cross-cutting issues, such as ageing, well-being and gender equality. We recommend a broader focus of WASH research and interventions in urban Africa to better reflect the demographic and health transitions happening. Abbreviations: CBA: Controlled Before and After; GSD: Government Service Delivery; IWDSSD: International Drinking-Water, Supply and Sanitation Decade (IDWSSD); KAP: Knowledge, Attitudes and Practices; IBD: Irritable Bowel Diseases; MDG: Millennium Development Goals; NTD: Neglected Tropical Diseases; PSSD: Private Sector Service Delivery; SDG: Sustainable Development Goals; SSA: Sub Saharan Africa; SODIS: Solar Disinfection System; STH: Soil Transmitted Helminths; RCT: Randomised Control Trial; WASH: Water Sanitation and Hygiene; WHO: World Health Organization

Impact of combining intermittent preventive treatment with home management of malaria in children less than 10 years in a rural area of Senegal: a cluster randomized trial

<p>Abstract</p> <p>Background</p> <p>Current malaria control strategies recommend (i) early case detection using rapid diagnostic tests (RDT) and treatment with artemisinin combination therapy (ACT), (ii) pre-referral rectal artesunate, (iii) intermittent preventive treatment and (iv) impregnated bed nets. However, these individual malaria control interventions provide only partial protection in most epidemiological situations. Therefore, there is a need to investigate the potential benefits of integrating several malaria interventions to reduce malaria prevalence and morbidity.</p> <p>Methods</p> <p>A randomized controlled trial was carried out to assess the impact of combining seasonal intermittent preventive treatment in children (IPTc) with home-based management of malaria (HMM) by community health workers (CHWs) in Senegal. Eight CHWs in eight villages covered by the Bonconto health post, (South Eastern part of Senegal) were trained to diagnose malaria using RDT, provide prompt treatment with artemether-lumefantrine for uncomplicated malaria cases and pre-referral rectal artesunate for complicated malaria occurring in children under 10 years. Four CHWs were randomized to also administer monthly IPTc as single dose of sulphadoxine-pyrimethamine (SP) plus three doses of amodiaquine (AQ) in the malaria transmission season, October and November 2010. Primary end point was incidence of single episode of malaria attacks over 8 weeks of follow up. Secondary end points included prevalence of malaria parasitaemia, and prevalence of anaemia at the end of the transmission season. Primary analysis was by intention to treat. The study protocol was approved by the Senegalese National Ethical Committee (approval 0027/MSP/DS/CNRS, 18/03/2010).</p> <p>Results</p> <p>A total of 1,000 children were enrolled. The incidence of malaria episodes was 7.1/100 child months at risk [95% CI (3.7-13.7)] in communities with IPTc + HMM compared to 35.6/100 child months at risk [95% CI (26.7-47.4)] in communities with only HMM (aOR = 0.20; 95% CI 0.09-0.41; <it>p </it>= 0.04). At the end of the transmission season, malaria parasitaemia prevalence was lower in communities with IPTc + HMM (2.05% versus 4.6% <it>p </it>= 0.03). Adjusted for age groups, sex, <it>Plasmodium falciparum </it>carriage and prevalence of malnutrition, IPTc + HMM showed a significant protective effect against anaemia (aOR = 0.59; 95% CI 0.42-0.82; <it>p </it>= 0.02).</p> <p>Conclusion</p> <p>Combining IPTc and HMM can provide significant additional benefit in preventing clinical episodes of malaria as well as anaemia among children in Senegal.</p

Plasmodium falciparum Transcriptome Analysis Reveals Pregnancy Malaria Associated Gene Expression

gene.-exposed women than from men.These findings suggest that other parasite proteins, such as PFI1785w, may contribute beside VAR2CSA to the pathogenesis of PAM. These data may be very valuable for future vaccine development

The future of African nowcasting

Nowcasting (weather forecasting predictions from zero to several hours) has enormous value and potential in Africa, where populations and economic activity are highly vulnerable to rapidly changing weather conditions. Timely issuing of warnings, a few hours before an event, can enable the public and decision-makers to take action. Rainfall radar estimates are not widely available in Africa, nor likely to be in the coming years, and numerical weather prediction (NWP) currently has low skill over the African continent. Therefore, for the delivery of nowcasting in Africa, satellite products are the best practical option and needed urgently (Roberts et al., 2021). Fifteen minute (or faster) updates of MSG (Meteosat Second Generation) images and NWC-SAF (Nowcasting Satellite Applications Facility) products are crucial for nowcasting to warn users (e.g. fisherfolk on Lake Victoria, flooding in urban areas, etc.) on pending severe storms. The possibility to have such products every 10 minutes, as well as data from the forthcoming MTG (Meteosat Third Generation) lightning imager, would be highly beneficial to all African countries, saving lives and livelihoods where high population growth and the most extreme impacts of climate change combine

Gametocyte carriage in uncomplicated Plasmodium falciparum malaria following treatment with artemisinin combination therapy: a systematic review and meta-analysis of individual patient data

BACKGROUND: Gametocytes are responsible for transmission of malaria from human to mosquito. Artemisinin combination therapy (ACT) reduces post-treatment gametocyte carriage, dependent upon host, parasite and pharmacodynamic factors. The gametocytocidal properties of antimalarial drugs are important for malaria elimination efforts. An individual patient clinical data meta-analysis was undertaken to identify the determinants of gametocyte carriage and the comparative effects of four ACTs: artemether-lumefantrine (AL), artesunate/amodiaquine (AS-AQ), artesunate/mefloquine (AS-MQ), and dihydroartemisinin-piperaquine (DP). METHODS: Factors associated with gametocytaemia prior to, and following, ACT treatment were identified in multivariable logistic or Cox regression analysis with random effects. All relevant studies were identified through a systematic review of PubMed. Risk of bias was evaluated based on study design, methodology, and missing data. RESULTS: The systematic review identified 169 published and 9 unpublished studies, 126 of which were shared with the WorldWide Antimalarial Resistance Network (WWARN) and 121 trials including 48,840 patients were included in the analysis. Prevalence of gametocytaemia by microscopy at enrolment was 12.1 % (5887/48,589), and increased with decreasing age, decreasing asexual parasite density and decreasing haemoglobin concentration, and was higher in patients without fever at presentation. After ACT treatment, gametocytaemia appeared in 1.9 % (95 % CI, 1.7–2.1) of patients. The appearance of gametocytaemia was lowest after AS-MQ and AL and significantly higher after DP (adjusted hazard ratio (AHR), 2.03; 95 % CI, 1.24–3.12; P = 0.005 compared to AL) and AS-AQ fixed dose combination (FDC) (AHR, 4.01; 95 % CI, 2.40–6.72; P < 0.001 compared to AL). Among individuals who had gametocytaemia before treatment, gametocytaemia clearance was significantly faster with AS-MQ (AHR, 1.26; 95 % CI, 1.00–1.60; P = 0.054) and slower with DP (AHR, 0.74; 95 % CI, 0.63–0.88; P = 0.001) compared to AL. Both recrudescent (adjusted odds ratio (AOR), 9.05; 95 % CI, 3.74–21.90; P < 0.001) and new (AOR, 3.03; 95 % CI, 1.66–5.54; P < 0.001) infections with asexual-stage parasites were strongly associated with development of gametocytaemia after day 7. CONCLUSIONS: AS-MQ and AL are more effective than DP and AS-AQ FDC in preventing gametocytaemia shortly after treatment, suggesting that the non-artemisinin partner drug or the timing of artemisinin dosing are important determinants of post-treatment gametocyte dynamics

Représentation haute résolution du système de mousson ouest africain avec un modèle climatique régional

L’objectif de ce travail est d’évaluer la capacité du modèle climatique régional RegCM3 à simuler de façon réaliste les principales caractéristiques du système de mousson ouest africain. La région ouest africaine est l’une des zones du globe dont la variabilité du climat est la moins maîtrisée. Sur une période de 12 ans (1989 - 2000), les caractéristiques moyennes de son climat sont simulées par la dernière version du modèle climatique régional (MCR) RegCM3 développé au Centre International de Physique Théorique Abdul Salam (ICTP, Trieste, Italie) et le modèle de circulation générale ECHAM5. Le RegCM3 est piloté à ses frontières latérales et initialisé par deux jeux de données : la dernière version de réanalyses haute résolution produite par le centre européen pour les prévisions météorologiques à moyen terme (CEPMMT) et les sorties du modèle de circulation générale couplé Océan-Atmosphère ECHAM5. Les profils de vents simulés sont comparés à ceux issus des données du CEPMMT. La pluie et la température de surface simulées par les modèles sont comparées aux observations du Climate Research Unit (CRU) et aux produits du Climate Prediction Center Merged Analysis of precipitation (CMAP) et du Global Precipitation Climatology Project (GPCP). L’analyse des résultats montre que quelque soit le forçage appliqué, le modèle RegCM3 simule bien les principaux éléments du climat ouest africain à savoir le flux de mousson dans les basses couches, le Jet d’Est Africain dans les couches moyennes, le Jet d’Est Tropical en haute troposphère, la température de surface et la distribution spatio-temporelle de la pluie. Les résultats encourageants obtenus dans ce travail ouvrent la perspective d’utiliser les sorties du MCG ECHAM5 pour initialiser et piloter le RegCM3 afin de réaliser des scénarii de changements climatiques futurs à haute résolution sur l’Afrique de l’Ouest et de faire des études d’impact sur l’environnement. This study aims to evaluate the capacity of the regional climate model RegCM3 to realistically simulate the main components of the West african monsoon system. Despite several studies, West African climate variability is still not well understood. The Regional climate model (RegCM3) developped at the Abdu Salam International Center for Theoretical Physics (Trieste / Italy) and the general circulation model ECHAM5 of Max Plack Institute (Germany) have been used to simulate the mean characteristics of West african climate from 1980 to 2000. Initial and lateral boundary conditions used to drive RegCM3 are from the European Center for Medium-range Weather Forecasts (ECMWF) model and the coupled ocean – atmosphere general circulation model ECHAM5. Wind profiles simulated by the RegCM3 and the ECHAM5 models are compared to ECMWF data. Simulated surface temperature and rainfall of models are validated with the observed data of the Climate Research Unit (CRU), the Climate Prediction Center Merged Analysis of precipitation (CMAP) and the Global Precipitation Climatology Project (GPCP) products. The analysis of results shows that regardless the applied forcing, the RegCM3 simulates well the main features of West African climate including low-levels monsoon flux, mid-levels African easterly jet, upper levels Tropical easterly jet, surface temperature and rainfall spatio-temporal characteristics. This promising diagnostics study will be followed by a RegCM3 high resolution climate change scenario simulation over West Africa using ECHAM5 outputs as forcing data in the aim to perform environmental impacts studies