Are there solar signals in the African monsoon and rainfall?

A review of areas of Africa where a signal in meteorological, hydrological or sedimentological parameters can be suspected to be of solar origin shows a variety of deposition. Nowhere is a persistent signal clearly defined, but many areas are involved: Nile basin, Ethiopian high plateau, Sahel, North and South Africa, Central and East Africa. Each area shows a repartition of rainfall distributed by successive sequences of drought and inundation, each lasting several years. Nearly all areas show a strong quasi-biennial fluctuation; in the Sahel, for instance, the mean annual river run-off in Senegal is about 2.3 years. The 11.4-year signal is also seen in many records of extreme (positive or negative) river run-off.

2021 ◽  
pp. 000313482110318
Author(s):  
Victor Kong ◽  
Cynthia Cheung ◽  
Nigel Rajaretnam ◽  
Rohit Sarvepalli ◽  
William Xu ◽  
...  

Introduction Combined omental and organ evisceration following anterior abdominal stab wound (SW) is uncommon and there is a paucity of literature describing the management and spectrum of injuries encountered at laparotomy. Methods A retrospective study was undertaken on all patients who presented with anterior abdominal SW involving combined omental and organ evisceration who underwent laparotomy over a 10-year period from January 2008 to January 2018 at a major trauma centre in South Africa. Results A total of 61 patients were eligible for inclusion and all underwent laparotomy: 87% male, mean age: 29 years. Ninety-two percent (56/61) had a positive laparotomy whilst 8% (5/61) underwent a negative procedure. Of the 56 positive laparotomies, 91% (51/56) were considered therapeutic and 9% (5/56) were non-therapeutic. In addition to omental evisceration, 59% (36/61) had eviscerated small bowel, 28% (17/61) had eviscerated colon and 13% (8/61) had eviscerated stomach. A total of 92 organ injuries were identified. The most commonly injured organs were small bowel, large bowel and stomach. The overall complication rate was 11%. Twelve percent (7/61) required intensive care unit admission. The mean length of hospital stay was 9 days. The overall mortality rate for all 61 patients was 2%. Conclusions The presence of combined omental and organ evisceration following abdominal SW mandates laparotomy. The small bowel, large bowel and stomach were the most commonly injured organs in this setting.


2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Alastair M. Sammon ◽  
Eugene J. Ndebia ◽  
Ekambaram Umapathy ◽  
Jehu E. Iputo

Background. Previous studies have established norms of 24-hour gastric pH profiles for western countries. This study was designed to establish the pattern for a rural African population with a high incidence of oesophageal cancer.Methods. After lower oesophageal manometry a probe was placed 10 cm distal to the lower oesophageal sphincter. We carried out 24-hour ambulatory monitoring of gastric pH on 59 healthy subjects. This was satisfactorily completed on 26 female and 18 male (age 21–64, median 35) subjects in the Transkei region of South Africa.Results. The mean 24 hour gastric pH was 2.84 and the mean night-time pH was 3.7. 40 volunteers recorded a night-time pH reaching over 4. 33 volunteers recorded a night-time pH over 7. Night-time alkalinisation was present for 136.4 minutes (25th centile 22.8, 75th centile 208.1) at pH4 or over, and 79.3 (2.5, 122.7) minutes at pH7 or over. Episodes of rapid alkaline rise were 17 (10, 47). 21.1% of these occurred while supine. 35 of 36 tested subjects were positive forH. pyloriIgG.Conclusion. Gastric alkalinisation is common in Transkei, at a higher pH than that reported in other studies, and is sustained longer. Nighttime alkalinisation is frequent. This suggests a high level of duodenogastric reflux.


2006 ◽  
Vol 361 (1470) ◽  
pp. 917-929 ◽  
Author(s):  
James F Kasting ◽  
Shuhei Ono

Earth's climate during the Archaean remains highly uncertain, as the relevant geologic evidence is sparse and occasionally contradictory. Oxygen isotopes in cherts suggest that between 3.5 and 3.2 Gyr ago (Ga) the Archaean climate was hot (55–85 °C); however, the fact that these cherts have experienced only a modest amount of weathering suggests that the climate was temperate, as today. The presence of diamictites in the Pongola Supergroup and the Witwatersrand Basin of South Africa suggests that by 2.9 Ga the climate was glacial. The Late Archaean was relatively warm; then glaciation (possibly of global extent) reappeared in the Early Palaeoproterozoic, around 2.3–2.4 Ga. Fitting these climatic constraints with a model requires high concentrations of atmospheric CO 2 or CH 4 , or both. Solar luminosity was 20–25% lower than today, so elevated greenhouse gas concentrations were needed just to keep the mean surface temperature above freezing. A rise in O 2 at approximately 2.4 Ga, and a concomitant decrease in CH 4 , provides a natural explanation for the Palaeoproterozoic glaciations. The Mid-Archaean glaciations may have been caused by a drawdown in H 2 and CH 4 caused by the origin of bacterial sulphate reduction. More work is needed to test this latter hypothesis.


2010 ◽  
Vol 15 (1) ◽  
Author(s):  
Folake O. Samuel ◽  
Abdulkadir A. Egal ◽  
Wilna H. Oldewage-Theron ◽  
Carin E. Napier ◽  
Christine S. Venter

This cross-sectional study assessed the risk of zinc deficiency in randomly selected children, aged between 7 and 11 years, living in a poor, peri-urban informal settlement in South Africa. Dietary intake of 149 respondents was evaluated by 24-hour recall and quantitative food frequency questionnaires. Anthropometric and biochemical indices of a subset of 113 were determined. Descriptive statistics, analysis of variance and Pearson correlations were computed using the Statistical Package for Social Sciences, version 14.0. Anthropometric data were analysed using the World Health Organization Anthro plus version 1.0.2 statistical software. Dietary data were analysed with FoodFinder® version 3. The mean age of the children was 9.0±1.1 years. Few zinc-rich sources appeared in the diet that was predominantly plant-based. Mean dietary zinc intake was 4.6±2.2 mg/day. The mean value of serum zinc was 66.4±21.5 µg/dL, with 46% of the children having values less than the 70 µg/dL cut-off. The findings indicate a high risk of zinc deficiency and suboptimal zinc status for the majority of this study population of children, possibly as a result of low consumption of food sources with high bioavailability of zinc, which invariably is a direct consequence of poverty and food insecurity.OpsommingDie doel van hierdie dwarsdeursnitstudie was die bepaling van die risiko van ’n sinktekort in ’n ewekansige steekproef van 7 tot 11 jaar-oue kinders, woonagtig in ’n arm, voorstedelike informele woonbuurt in Suid Afrika. Dieetinnames van 149 respondente is geëvalueer deur 24-uur herroep en kwantitatiewe voedselfrekwensie vraelyste. Antropometriese en biochemiese indikatore van ’n kleiner steekproef van 113 is ook bepaal. Beskrywende statistiek, analise van variansie en Pearsonkorrelasies is bepaal deur die Statistical Package for Social Sciences, uitgawe 14.0. Antropometriese data is geanaliseer deur die statistiese program, Anthro plus, uitgawe 1.0.2, van die Wêreld Gesondheid Organisasie. Dieetdata is met behulp van FoodFinder® uitgawe 3 geanaliseer. Die gemiddelde ouderdom van die kinders was 9.0±1.1 jaar. Min sinkryke voedselbronne is in die hoofsaaklik plantryke dieet waargeneem. Die gemiddelde sinkinname was 4.6±2.2 mg/dag en die gemiddelde serumsinkwaarde was 66.4±21.5 µg/dL, met 46% van die kinders se waardes onder die 70 µg/dL afsnypunt. Die bevindings dui op ’n hoë risiko vir sinktekort en suboptimale sinkstatus vir die meerderheid van hierdie kinders, moontlik as gevolg van die swak inname van voedselbronne met hoë biobeskikbare sink, wat gewoonlik ’n direkte gevolg van armoede en huishoudelike voedsel insekuriteit is.


Parasitology ◽  
2018 ◽  
Vol 146 (3) ◽  
pp. 372-379 ◽  
Author(s):  
Chengyun Yang ◽  
Ruimin Zhou ◽  
Ying Liu ◽  
Suhua Li ◽  
Dan Qian ◽  
...  

AbstractEfficacious antimalarial drugs are important for malaria control and elimination, and continuous monitoring of their efficacy is essential. The prevalence and distribution of Pfmdr1 were evaluated in African migrant workers in Henan Province. Among 632 isolates, 13 haplotypes were identified, NYSND (39.87%, 252/632), YYSND (2.85%, 18/632), NFSND (31.01%, 196/632), NYSNY (0.47%, 3/632), YFSND (13.77%, 87/632), NFSNY (0.32%, 2/632), YYSNY (2.06%, 13/632), YFSNY (0.16%, 1/632), N/Y YSND (1.90%, 12/632), N Y/F SND (6.17%, 39/632), N/Y Y/F SND (0.47%, 3/632), YYSN D/Y (0.16%, 1/632) and N/Y FSND (0.79%, 5/632). The highest frequency of NYSND was observed in individuals from North Africa (63.64%, 7/11), followed by South Africa (61.33%, 111/181), Central Africa (33.33%, 56/168), West Africa (28.94%, 68/235) and East Africa (27.03%, 10/37) (χ2 = 54.605, P < 0.05). The highest frequency of NFSND was observed in East Africa (48.65%, 18/37), followed by West Africa (39.14%, 92/235), Central Africa (26.79%, 45/168), South Africa (22.65%, 41/181) and North Africa (9.09%, 1/11) (χ2 = 22.368 P < 0.05). The mutant prevalence of codons 86 and 184 decreased. These data may provide complementary information on antimalarial resistance that may be utilized in the development of a treatment regimen for Henan Province.


Fluids ◽  
2020 ◽  
Vol 5 (3) ◽  
pp. 147 ◽  
Author(s):  
Fernand Assene ◽  
Yves Morel ◽  
Audrey Delpech ◽  
Micael Aguedjou ◽  
Julien Jouanno ◽  
...  

In this paper, we analyse the results from a numerical model at high resolution. We focus on the formation and maintenance of subsurface equatorial currents in the Gulf of Guinea and we base our analysis on the evolution of potential vorticity (PV). We highlight the link between submesoscale processes (involving mixing, friction and filamentation), mesoscale vortices and the mean currents in the area. In the simulation, eastward currents, the South and North Equatorial Undercurrents (SEUC and NEUC respectively) and the Guinea Undercurrent (GUC), are shown to be linked to the westward currents located equatorward. We show that east of 20° W, both westward and eastward currents are associated with the spreading of PV tongues by mesoscale vortices. The Equatorial Undercurrent (EUC) brings salty waters into the Gulf of Guinea. Mixing diffuses the salty anomaly downward. Meridional advection, mixing and friction are involved in the formation of fluid parcels with PV anomalies in the lower part and below the pycnocline, north and south of the EUC, in the Gulf of Guinea. These parcels gradually merge and vertically align, forming nonlinear anticyclonic vortices that propagate westward, spreading and horizontally mixing their PV content by stirring filamentation and diffusion, up to 20° W. When averaged over time, this creates regions of nearly homogeneous PV within zonal bands between 1.5° and 5° S or N. This mean PV field is associated with westward and eastward zonal jets flanking the EUC with the homogeneous PV tongues corresponding to the westward currents, and the strong PV gradient regions at their edges corresponding to the eastward currents. Mesoscale vortices strongly modulate the mean fields explaining the high spatial and temporal variability of the jets.


1985 ◽  
Vol 4 (3) ◽  
pp. 93-98 ◽  
Author(s):  
T. P. C. Van Robbroeck

Most economic development in South Africa has taken place on the dry plateau of the interior following the discovery of minerals. The much smaller wetter parts get most of the run-off and have generally limited possibilities for advantageous use of their water resources. Consequently, it is logical to transfer water between basins with a surplus to ones experiencing shortages. There is a body of opinion that such transfers should be stopped in the interest of the decentralistion policy, but such action is not considered in the national interest. The intricate system of inter-basin transfer from the Komati, the Usutu and the Vaal River to supply the Eastern Transvaal coalfields is described. This system has shown its flexibility during the recent drought. The most important inter-basin transfer scheme is the Tugeia- Vaal Project which is described in broad terms. The advantages of the principle of reserve storage and of co-operation with Escom are dealt with. Possible further projects to augment the Vaal River supplies are mentioned. Other inter-basin transfer schemes implemented by the Department of Water Affairs such as the Orange River Project, the Riviersonderend-Berg River Project and others of lesser importance are dealth with.


1953 ◽  
Vol 1 (3) ◽  
pp. 175-185
Author(s):  
W. Scheijgrond

Trials were carried out at 2 stations in the Netherlands in the period 1949-51 to compare the amounts of dry matter and crude protein yielded per ha. by 5 different types of lucerne. The Northern French varieties (Du Puits, Flamande Chartain-villiers and Flamande Flandria) gave considerably higher yields of dry matter and protein than Provence or Italian lucerne. A further trial was carried out in the Netherlands in co-operation with O.E.E.C., in which the performances of varieties from Western, Eastern, Central and Southern Europe, North and South America, New Zealand, India and South Africa were compared. The results are tabulated under the following headings: yield in comparative figures, speed of regrowth after winter, earliness of flowering, degree of infestation by grasses and cold-resistance. The Northern French varieties Du Puits, Flamande Flandria, Flamande Chartainvilliers, Flamande Socheville and Flamande C49, gave higher yields of dry matter and crude protein, regrew more rapidly after winter and were less susceptible to infestation by grasses than the other varieties tested. Their cold-resistance was satisfactory. There were no considerable differences in performance between the Northern French varieties tested.-W.J.B. (Abstract retrieved from CAB Abstracts by CABI’s permission)


2005 ◽  
Vol 56 (2) ◽  
pp. 163 ◽  
Author(s):  
Ben J. Kefford ◽  
Carolyn G. Palmer ◽  
Dayanthi Nugegoda

Salinity is rising in many southern African and Australian rivers with unknown effects on aquatic organisms. The extent of spatial variation, at any scale, in salt tolerances of aquatic organisms is unknown, so whether data from one location is applicable elsewhere is also unknown. The acute tolerances (72-h median lethal concentration (LC50)) to sea salt of 49 macroinvertebrate taxa from the south-east Eastern Cape (SEEC), South Africa were compared with those of 57 species from the Barwon Catchment, Victoria, Australia. The mean LC50 values from both locations were similar (Barwon: 31 and SEEC: 32 mS cm−1) and less abundant (rare) taxa tended to be more tolerant than more abundant (common) taxa. There was, however, a greater range of LC50 values (5.5–76 mS cm−1) in the Barwon Catchment than in the SEEC (11–47 mS cm−1). The species sensitivity distribution (SSD) for SEEC taxa was bimodal whereas the Barwon Catchment’s SSD had a single peak. With few exceptions, members of an order had similar tolerances in both locations. The differences in SSD between locations were related to crustacean, odonate and non-arthropod relative richness. Although it is not ideal to extrapolate SSDs from one location to another, it may be reasonable to assume similar salinity tolerances among related taxa.


2020 ◽  
Author(s):  
Andrit Lourens ◽  
Peter Hodkinson ◽  
Romy Parker

Abstract Background: Acute pain is frequently encountered in the prehospital setting, and therefore, a fundamental aspect of quality emergency care. Research has shown a positive association between health care providers’ knowledge of, and attitudes towards pain and pain management practices. This study aimed to describe the knowledge, attitudes, and practices of emergency care providers regarding acute pain assessment and management in the prehospital setting, in the Western Cape, South Africa. The specific objectives were to, identify gaps in pain knowledge; assess attitudes regarding pain assessment and management; describe pain assessment and management behaviours and practices; and identify barriers to and enablers of pain care. Methods: A web-based descriptive cross-sectional survey was conducted among emergency care providers of all qualifications, using a face-validated Knowledge, Attitudes and Practices of Pain survey. Results: Responses of 100 participants was included in the analysis. The survey response rate could not be calculated. The mean age of respondents was 34.74 (SD8.13) years and the mean years’ experience 10.02 (SD6.47). Most respondents were male (69%), employed in the public/government sector (93%) as operational practitioners (85%) with 54% of respondents having attended medical education on pain care in the last two years. The mean percentage for knowledge and attitudes regarding pain among emergency care providers was 58.01% (SD15.66) with gaps identified in various aspects of pain and pain care. Practitioners with higher qualifications, more years’ experience and those who did not attend medical education on pain, achieved higher scores. Alcohol and drug use by patients were the most selected barrier to pain care while the availability of higher qualified practitioners was the most selected enabler. When asked to record pain scores, practitioners were less inclined to assign scores which were self-reported by the patients in the case scenarios. The participant dropout rate was 35%. Conclusion: Our results suggest that there is suboptimal knowledge and attitudes regarding pain among emergency care providers in the Western Cape, South Africa. Further, gaps in pain knowledge, attitudes and practices were identified. Some barriers and enablers of pain care in the South African prehospital setting were identified but further research is indicated.


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