Sites In West Africa Research Articles

Novel functional insights into ischemic stroke biology provided by the first genome-wide association study of stroke in indigenous Africans

BackgroundAfrican ancestry populations have the highest burden of stroke worldwide, yet the genetic basis of stroke in these populations is obscure. The Stroke Investigative Research and Educational Network (SIREN) is a multicenter study involving 16 sites in West Africa. We conducted the first-ever genome-wide association study (GWAS) of stroke in indigenous Africans.MethodsCases were consecutively recruited consenting adults (aged > 18 years) with neuroimaging-confirmed ischemic stroke. Stroke-free controls were ascertained using a locally validated Questionnaire for Verifying Stroke-Free Status. DNA genotyping with the H3Africa array was performed, and following initial quality control, GWAS datasets were imputed into the NIH Trans-Omics for Precision Medicine (TOPMed) release2 from BioData Catalyst. Furthermore, we performed fine-mapping, trans-ethnic meta-analysis, and in silico functional characterization to identify likely causal variants with a functional interpretation.ResultsWe observed genome-wide significant (P-value < 5.0E−8) SNPs associations near AADACL2 and miRNA (MIR5186) genes in chromosome 3 after adjusting for hypertension, diabetes, dyslipidemia, and cardiac status in the base model as covariates. SNPs near the miRNA (MIR4458) gene in chromosome 5 were also associated with stroke (P-value < 1.0E−6). The putative genes near AADACL2, MIR5186, and MIR4458 genes were protective and novel. SNPs associations with stroke in chromosome 2 were more than 77 kb from the closest gene LINC01854 and SNPs in chromosome 7 were more than 116 kb to the closest gene LINC01446 (P-value < 1.0E−6). In addition, we observed SNPs in genes STXBP5-AS1 (chromosome 6), GALTN9 (chromosome 12), FANCA (chromosome 16), and DLGAP1 (chromosome 18) (P-value < 1.0E−6). Both genomic regions near genes AADACL2 and MIR4458 remained significant following fine mapping.ConclusionsOur findings identify potential roles of regulatory miRNA, intergenic non-coding DNA, and intronic non-coding RNA in the biology of ischemic stroke. These findings reveal new molecular targets that promise to help close the current gaps in accurate African ancestry-based genetic stroke’s risk prediction and development of new targeted interventions to prevent or treat stroke.

Consistent yield performance of rice genotypes grown under irrigated conditions in wet and dry seasons in West Africa

ContextRice double cropping in irrigated systems is essential for increasing rice production and ensuring food security in West Africa. Rice breeding programs must develop genotypes that are expected to perform well either across wet and dry seasons or for a specific season. ObjectiveThis study aimed to investigate the consistency of genotypic performance across two seasons and identify high-yielding genotypes and their characteristics. Methods50 diverse genotypes were grown under irrigated conditions in wet and dry seasons at three sites in West Africa (M’bé in Côte d’Ivoire, and Fanaye and Ndiaye in Senegal) for three years (2018–2020). ResultsMean grain yield across all genotypes was higher in dry season in Fanaye (593 vs. 495 g/m2) and Ndiaye (737 vs. 415 g/m2) than in wet season, but the same for the two seasons in M’bé (512 vs. 507 g/m2). The consistency of genotypic performance across wet and dry seasons was the highest in M’bé (r = 0.88, P < 0.01), followed by Fanaye (r = 0.71, P < 0.01), and lowest in Ndiaye (r = 0.49, P < 0.01). Thus, correlations for yields between two seasons becomes poorer as difference in yield level between two seasons becomes larger. Two (NSIC Rc240 and Giza 178) and one (MG 2::IRGC 79837-1) genotypes from other regions were identified for high yield in both seasons in Côte d’Ivoire and Senegal, respectively. High-yielding genotypes were characterized by large aboveground biomass and high harvest index in both seasons in all three sites. Grain yield was positively correlated with days to heading and number of grains per panicle in both seasons in M’bé and Fanaye. In Ndiaye, none of the yield components was consistently related to grain yield across two seasons. ConclusionsIt is possible for rice breeding programs to develop and identify genotypes that are expected to perform well in two seasons. High-yielding genotypes identified in this study can be used as donors for improving rice productivity in West Africa. ImplicationsField experiments were conducted in three sites in two countries only, and further effort is needed to evaluate consistency of genotypic performance across diverse agro-ecological zones in West Africa.

Itinerant lifestyle and congregation of lesser kestrels in West Africa

Trans‐Saharan migrants often spend a large proportion of their annual cycle wintering in the Sahel. Advances in fieldwork and tracking technology have greatly enhanced our ability to study their ecology in these areas. Using GPS‐tracking we aimed to investigate the little known non‐breeding movements of the lesser kestrel Falco naumanni in sub‐Saharan Africa. We segment non‐breeding tracks (n = 79 tracks by 54 individuals) into staging events (131 ± 25 days per non‐breeding cycle), itinerant movements between staging sites (11 ± 10 days), and non‐directed exploratory movements (6 ± 5 days). We then describe timing and directionality of itinerant movements by male and female kestrels throughout the non‐breeding season. Regardless of sex, lesser kestrels spent on average 89% of the non‐breeding season staging at two (range = 1–4) sites in West Africa. At the end of September, kestrels arrived along a broad front throughout the northern Sahel. By December, however, they congregated into two distinct clusters in Senegal and along the Malian–Mauritanian border. The birds stayed for longer periods and showed greater daily activity in the latter areas, compared to their first and intermediate ones. Among 24 individuals tracked along multiple annual cycles, 20 individuals consistently used the Senegalese or Malian–Mauritanian cluster. The remaining four birds either used these clusters in the 2nd or 3rd year of tracking or alternated between them across different years. The eastward and westward itinerant movements of lesser kestrels during the non‐breeding season, coupled with their tendency to cluster geographically towards the end, differ from the southward movements of other insectivorous raptors in West Africa. While 31% of Spanish lesser kestrels converged in Senegal, where roosts of &gt; 20 000 birds are known, 68% moved into the Malian‐Mauritanian border region where more groundwork is needed.

Socio-environmental implications of shifting subsistence practices at Diallowali, a Late Stone Age site system in the Middle Senegal Valley

In this paper we present the results of archaeological research at the Late Stone Age site of Diallowali, located along the western edge of the Middle Senegal Valley, northern Senegal. As the occupation spans the period between 3100-2400 years BP, it is contemporary with few other West African sites, and therefore represents a unique – and uniquely detailed – archive. Excavations conducted between 2014–2017 revealed deeply stratified and dense deposits, yielding more than 5,000kg of pottery and 169kg of faunal material – the largest faunal assemblage of any site in West Africa. Thus, the present study focuses on the zooarchaeological data and their implications for shifting environmental conditions, subsistence practices, and social institutions at the site. The faunal assemblage reflects the exploitation of a remarkable diversity of wild animals, including a range of bovids, suids, carnivores, rodents, hippopotami, birds, and various aquatic resources – representing local conditions at the end of the African Humid Period. Interestingly, the consistent presence of domestic livestock, as well as Bos taurus figurines and ceramic ‘arm-bands’ throughout the occupation support a connection to Saharan agro-pastoral communities possibly escaping the Late Holocene aridification. Therefore, the keeping of low numbers of Bostaurus and Ovis/Capra, while maintaining a high reliance on hunting, fishing, and gathering wild plants, likely functioned as a risk-buffering strategy to manage against environmentally unpredictable periods.

Safety and immunogenicity of the two-dose heterologous Ad26.ZEBOV and MVA-BN-Filo Ebola vaccine regimen in infants: a phase 2, randomised, double-blind, active-controlled trial in Guinea and Sierra Leone

This study assessed the safety and immunogenicity of the Ad26.ZEBOV and MVA-BN-Filo Ebola virus (EBOV) vaccine regimen in infants aged 4-11 months in Guinea and Sierra Leone. In this phase 2, randomised, double-blind, active-controlled trial, we randomly assigned healthy infants (1:1 in a sentinel cohort, 5:2 for the remaining infants via an interactive web response system) to receive Ad26.ZEBOV followed by MVA-BN-Filo (Ebola vaccine group) or two doses of meningococcal quadrivalent conjugate vaccine (control group) administered 56 days apart. Infants were recruited at two sites in west Africa: Conakry, Guinea, and Kambia, Sierra Leone. All infants received the meningococcal vaccine 8 months after being randomly assigned. The primary objective was safety. The secondary objective was immunogenicity, measured as EBOV glycoprotein-binding antibody concentration 21 days post-dose 2, using the Filovirus Animal Non-Clinical Group ELISA. This study is registered with ClinicalTrials.gov (NCT03929757) and the Pan African Clinical Trials Registry (PACTR201905827924069). From Aug 20 to Nov 29, 2019, 142 infants were screened and 108 were randomly assigned (Ebola vaccine n=75; control n=33). The most common solicited local adverse event was injection-site pain (Ebola vaccine 15 [20%] of 75; control four [12%] of 33). The most common solicited systemic adverse events with the Ebola vaccine were irritability (26 [35%] of 75), decreased appetite (18 [24%] of 75), pyrexia (16 [21%] of 75), and decreased activity (15 [20%] of 75). In the control group, ten (30%) of 33 had irritability, seven (21%) of 33 had decreased appetite, three (9%) of 33 had pyrexia, and five (15%) of 33 had decreased activity. The frequency of unsolicited adverse events was 83% (62 of 75 infants) in the Ebola vaccine group and 85% (28 of 33 infants) in the control group. No serious adverse events were vaccine-related. In the Ebola vaccine group, EBOV glycoprotein-binding antibody geometric mean concentrations (GMCs) at 21 days post-dose 2 were 27 700 ELISA units (EU)/mL (95% CI 20 477-37 470) in infants aged 4-8 months and 20 481 EU/mL (15 325-27 372) in infants aged 9-11 months. The responder rate was 100% (74 of 74 responded). In the control group, GMCs for both age groups were less than the lower limit of quantification and the responder rate was 3% (one of 33 responded). Ad26.ZEBOV and MVA-BN-Filo was well tolerated and induced strong humoral responses in infants younger than 1 year. There were no safety concerns related to vaccination. Janssen Vaccines & Prevention and Innovative Medicines Initiative 2 Joint Undertaking. For the French translation of the abstract see Supplementary Materials section.

Testing the suitability of Marginal Distribution Sampling as a gap‐filling method using some meteorological data from seven sites in West Africa

AbstractMeteorological data are useful in many fields related to climate change studies and their use often requires them to be continuous. To date, marginal distribution sampling (MDS), which consists of filling a missing value with an average of the data that are found in similar meteorological conditions over a flexible time window, is widely adopted in the FLUXNET community. In this work, we evaluate the performance of MDS at diurnal and monthly scales for the incoming shortwave radiation (Swin), relative humidity (RH), vapour pressure deficit (VPD), air and soil temperatures (Tair, Tsoil) acquired across seven sites in West Africa. The criteria tested are the MDS's ability to (i) fill gaps while reducing the error rate, (ii) represent proper variability within data and finally (iii) ensure homogeneity between its output and original data. We found during the daytime that MDS is adequate for filling gaps in Swin when both reducing error rate and a good representation of variability are targeted. If the goal is to have a small error rate, then this approach is recommended for all investigated variables except VPD. During nighttime, MDS is satisfactory to minimize the error when filling gaps in Tair, Tsoil and RH while to represent their variabilities it becomes more sensitive to the rate of missing data. At a monthly scale, the gap‐filled data are consistent with the original ones for all variables attributable to data size and a wider sliding window that allows more data under similar conditions to be considered.

Estimating mixture hybrid Weibull distribution parameters for wind energy application using Bayesian approach

The Weibull distribution function is essential for planning and designing wind-farm implementation projects and wind-resource assessments. However, the Weibull distribution is limited for those areas with high frequencies of calm winds. One solution is to use the hybrid Weibull distribution. In fact, when the wind speed data present heterogeneous structures, it makes sense to group them into classes that describe the different wind regimes. However, the single use of the Weibull distribution presents fitting errors that should be minimized. In this context, mixture distributions represent an appropriate alternative for modelling wind-speed data. This approach was used to combine the distributions associated with different wind-speed classes by weighting the contribution of each of them. This study proposes an approach based on mixtures of Weibull distributions for modelling wind-speed data in the West Africa region. The study focused on mixture Weibull (WW-BAY) and mixture hybrid Weibull (WWH-BAY) distributions using Bayes' theorem to characterize the wind speed distribution over twelve years of recorded data at the Abuja, Accra, Cotonou, Lome, and Tambacounda sites in West Africa. The parameters of the models were computed using the expectation-maximization (E-M) algorithm. The parameters of the models were estimated using the expectation-maximization (E-M) algorithm. The initial values were provided by the Levenberg-Marquardt algorithm. The results obtained from the proposed models were compared with those from the classical Weibull distribution whose parameters are estimated by some numerical method such as the energy pattern factor, maximum likelihood, and the empirical Justus methods based on statistical criteria. It is found that the WWH-BAY model gives the best prediction of power density at the Cotonou and Lome sites, with relative percentage error values of 0.00351 and 0.01084. The energy pattern factor method presents the lowest errors at the Abuja site with a relative percentage error value of -0.54752, Accra with -0.55774, and WW-BAY performs well for the Tambacounda site with 0.19232. It is recommended that these models are useful for wind energy applications in the West African region.

Using data and models to infer climate and environmental changes during the Little Ice Age in tropical West Africa

Abstract. Here we present hydrological and vegetation paleo-data extracted from 28 sites in West Africa from 5∘ S to 19∘ N and the past1000/PMIP4 IPSL-CM6A-LR climate model simulations covering the 850–1850 CE period to document the environmental and climatic changes that occurred during the Little Ice Age (LIA). The comparison between paleo-data and model simulations shows a clear contrast between the area spanning the Sahel and the savannah in the north, characterized by widespread drought, and the equatorial sites in the south, where humid conditions prevailed. Particular attention was paid to the Sahel, whose climatic evolution was characterized by a progressive drying trend between 1250 and 1850 CE. Three major features are highlighted: (1) the detection of two early warning signals around 1170 and 1240 CE preceding the onset of the LIA drying trend; (2) a tipping point at 1800–1850 CE characterized by a rainfall drop and an environmental degradation in the Sahel; and (3) a succession of drying events punctuating the LIA, the major one of which was dated to around 1600 CE. The climatic long-term evolution of the Sahel is associated with a gradual southward displacement of the Inter-Tropical Convergence Zone induced by the radiative cooling impacts of major volcanic eruptions that have punctuated the last millennium.

West African e-waste-soil assessed with a battery of cell-based bioassays

Soil samples randomly taken from major e-waste sites in West Africa (Nigeria, Benin and Ghana) were examined for an extensive range of organic contaminants. Cytotoxicity measurements and assessment of activation of xeno-sensing receptors from fish (Atlantic cod) were employed as a battery of in vitro biological assays to explore the quality and toxicity profile of West African e-waste soil. The concentrations of the measured contaminants of emerging concerns (CECs) and persistent organic pollutants (POPs) in the e-waste soil differs significantly from the reference soil with chemical profiles typically dominated by legacy polybrominated diphenyl ethers (PBDEs) (405.8 μgkg−1) and emerging organophosphate ester flame retardant tris (1-chloro-2-propyl) phosphate (TCPP) (404 μgkg−1), in addition to the short chain perfluorobutane sulfonate (PFBS) (275.3 μgkg−1) and perfluorobutanoate (PFBA) (16 μgkg−1). The study revealed that perfluorooctanoic acid (PFOA) occurred only in e-waste soil from Ghana and ranged from 2.6 to 5.0 μgkg−1. Overall, non-polar e-waste soil-derived extracts had a stronger effect on COS-7 cell viability than the polar extracts and elutriates. The highest receptor activation was observed with single polar and non-polar extracts from the Nigeria and Benin sites, indicating hotspots with Er-, PPARa- and Ahr-agonist activities. Thus, the results obtained with our battery of in vitro biological assays underscored these e-waste sites as remarkably polluted spots with complex toxicity profiles of great concern for human and environmental health.

Satellite tracking reveals sex-specific migration distance in green turtles (Chelonia mydas).

Satellite tracking is a key tool for studying sea turtles in the wild. Most tracking has been performed on adult females however, leaving knowledge gaps regarding other population segments, such as adult males. By satellite tracking 12 male green turtles (Chelonia mydas) at a breeding site in West Africa, we describe their movements from the breeding to the foraging grounds and compare migrations with those of 13 females tracked in the same season. During the mating period, some males remained near the focal nesting site, while others performed exploratory movements, apparently to visit other nearby rookeries. Males migrated on average shorter distances to foraging grounds (377 km, range 50-1081, n = 9) compared to females (1038 km, range 957-1850, n = 11]). Importantly, male foraging areas overlapped with previously described areas for females, suggesting sex-specific migration distances are not derived from differences in habitat selection. Strong support for differential migration by sex in sea turtles has hitherto been found in just one other species, but indications are that it may be a general feature in this group. These findings have important implications for our understanding of the interplay between reproductive roles and movement ecology of these emblematic animals.

Relationality, Individuality and Entanglements of Helping in the Context of a Touristic Vaccine Trial

This article explores the idea of relationality and distributive agency in the context of a clinical vaccine trial. The diarrhoea vaccine trial was conducted in Western Africa, but as a unique element, recruited Finnish adults as trial participants, who travelled to the trial site to West Africa. Engaging with previous research on clinical trials in the global South that has emphasized the relationality and social embeddedness of Southern trial subjects, this article argues for an enacted social-material relationality of any research subject. As the vaccine trial under study transformed into practices and ideas of helping, the analysis illustrates forms of relational subjectivity and distributive agency by focusing on the notion of helping. The analysis is based on the trial participants’ accounts and practices, and draws on qualitative interviews (51) and ethnographic observation conducted between 2017 and 2019 at the trial site in West Africa.

In vitro cytotoxic assessment of e-waste-related chemical pollution in impacted soil matrix.

The environmental quality and toxicity of soil from some selected informal e-waste sites in West Africa was assessed on PLHC-1 liver cells. In addition, toxicity mechanisms such as apoptosis, necrosis and necroptosis were analysed in order to determine the effect of the actual chemical mixture present in the e-waste soil matrix. The investigation revealed that although e-waste soil extracts (polar and non-polar) and elutriates were significantly cytotoxic at the tested concentration (16mg soil EQ/ml), PLHC-1 cell viability was not reduced below 50%. The non-polar extracts were more toxic compared to polar extracts and elutriates. The cytotoxic potency of soil from the informal e-waste-recycling sites ranged in this order: Alaba > Godome-Kouhounou > Agbogblosie. The study revealed that all e-waste soil extracts and elutriates induced significant (P < 0.01) PLHC-1 cell death by apoptosis and necrosis; however, cell death by apoptosis was higher compared to that by necrosis. The results indicated that except for non-polar extracts (N4, B4 and G4) from open burning areas that induced significant (P < 0.01) PLHC-1 cell death by necroptosis, other extracts and elutriates could not cause cell death by necroptosis. The study has demonstrated that soils from the Alaba e-waste site in Lagos could be more toxic than soils from Godome-Kouhounou (Cotonou) and Agbogblosie (Accra) e-waste sites and further highlighted open burning as an informal e-waste-handling method with greater negative impact on soil quality in the e-waste sites. The study emphasizes the urgent need for regulatory agencies to introduce regular residue-monitoring programmes in order to forestall the adverse effects of soil pollution episodes in the e-waste sites.

Stringing Together Cowrie Shells in the African Archaeological Record with Special Reference to Southern Africa

Archaeological explorations of the meaning of ‘trade objects’, such as glass beads and cowrie shells, remain hampered by theoretical and methodological limitations in both their analyses and interpretations. In this paper, we develop a methodology for critically engaging in multi-scalar questions of the circulation, exchange, and value of cowrie shells in African archaeological contexts. Species, size, dorsal modifications, and depositional contexts were compared across five sites from South Africa dating between 750 and 1350 CE. These results were positioned within a review of cowries from archaeological sites in the region and compared to the documented distribution of cowries from wider African archaeological contexts. Monetaria annulus were the prevalent cowrie species in southern African archaeological contexts over the last 2000 years, with a notable absence of Monetaria moneta, prevalent at contemporaneous sites in West Africa, as well as a variety of endemic southern African species. Breakage patterns on the dorsal surface correspond to different modification techniques, such as chipping and grinding. Combined analyses of modification, use-wear, and depositional patterns show variation, revealing a diversity in the biographies of individual cowries. While a comparison of the distribution of cowries across the continent confirms the circulation of cowries through known trade routes, such as the trans-Saharan trade network and the European mercantile network, they also reveal new pathways for exchange that highlight the need for further exploration of intra African networks. Finally, the breadth of the results of this study demonstrates the value of a focus on a specific artefact to address a wide range of themes, from exchange to the archaeology of everyday life.

Spatially different annual cycles but similar haemosporidian infections in distant populations of collared sand martins

BackgroundPopulations of long-distance migratory birds experience different environments and are consequently exposed to different parasites throughout their annual cycles. Though, specific whereabouts and accompanied host-parasite interactions remain unknown for most migratory passerines. Collared sand martins (Riparia riparia) breeding in the western Palaearctic spend the nonbreeding period in Africa, but it is not yet clear whether specific populations differ in overwintering locations and whether these also result in varying infections with vector-transmitted endoparasites.ResultsGeolocator tracking revealed that collared sand martins from northern-central and central-eastern Europe migrate to distant nonbreeding sites in West Africa and the Lake Chad basin in central Africa, respectively. While the ranges of these populations were clearly separated throughout the year, they consistently spent up to 60% of the annual cycle in Africa. Ambient light recorded by geolocators further indicated unsheltered roosting during the nonbreeding season in Africa compared to the breeding season in Europe.We found 5–26% prevalence of haemosporidian parasites in three breeding populations and one migratory passage population that was only sampled but not tracked. In total, we identified seven Plasmodium and nine Haemoproteus lineages (incl. two and seven new lineages, respectively), the latter presumably typical for swallows (Hirundinae) hosts. 99.5% of infections had a low intensity, typical for chronic infection stages, whereas three individuals (0.5%) showed high parasitaemia typical for acute infections during spring migration and breeding.ConclusionsOur study shows that blood parasite infections are common in several western Palaearctic breeding populations of collared sand martins who spent the nonbreeding season in West Africa and the lake Chad region. Due to long residency at the nonbreeding grounds blood parasite transmissions may mainly occur at host population-specific residences sites in Europe and Africa; the latter being likely facilitated by unsheltered roosting and thus high vulnerability to hematophagous insects. The rare cases of high parasitaemia during spring migration and breeding further indicates either relapses of chronic infection or primary infections which occurred shortly before migration and during breeding.

The Effect of Prolonged Pre-Operative Halo Gravity Traction for Severe Spinal Deformities on the Cervical Spine Radiographs.

Retrospective review of consecutive series. The study sought to assess the effect of prolonged pre-operative halo gravity traction (HGT) on the c-spine radiographs. Data of 37 pediatric and adult patients who underwent ≥ 12wks pre-op HGT prior to definitive spine surgery from 2013-2015 at a single site in West Africa was reviewed. Radiographic assessment of the c-spine including ADI, SVA and C2-C7 Lordosis were done at pre HGT and at 4 weekly intervals. Paired T-Test was performed to evaluate changes in these parameters during HGT. 37pts, 18/19 (F/M). Average age 18.2yrs. Diagnoses: 22 idiopathic, 6 congenital, 3 Post TB, 2 NM and 4 NF. Average duration of HGT: 125 days. Baseline coronal Cobb:130 deg, corrected 30% in HGT; baseline sagittal Cobb:146 deg, corrected 32% post HGT. Baseline ADI (3.17 ± 0.63 mm) did not change at 4wks (P > 0.05) but reduced at 8wks (2.80 ± 0.56 mm) and 12wks (2.67 ± 0.51 mm) post HGT (P < 0.05). Baseline HGT SVA (20.7 ± 14.98 mm) significantly improved at 4wks (11.55 ± 10.26 mm), 8wks (7.54 ± 6.78 mm) and 12wks (8.88 ± 4.5 mm) (P < 0.05). Baseline C2-C7 lordosis (43 ± 20.1 deg) reduced at 4wks (26 ± 16.37 deg), 8wks (17.8 ± 14.77 deg) and 12wks (16.7 ± 11.33 deg) post HGT (P < 0.05). There was no incidence of atlanto-axial instability on flexion extension radiographs at any interval. Prolonged HGT, while providing partial correction of severe spine deformities, also appeared to have no adverse effect on atlanto-axial stability or cervical alignment. Therefore, HGT can be safely applied for several weeks in the preoperative management of severe spine deformities in pediatric/adult patients.

Surgical management of complex post-tuberculous kyphosis among African patients: clinical and radiographic outcomes for a consecutive series treated at a single institution in West Africa.

Retrospective review of consecutive series. To assess the clinical and radiographic outcomes after surgical management of post-tuberculous kyphosis. Post-tuberculous (TB) kyphosis can lead to progressive pulmonary and neurological deterioration. Surgery is indicated to decompress neural elements and correct the spine deformity. Although posterior vertebral column resection (PVCR) has been established as the treatment of choice for severe TB kyphosis, there is paucity of studies on the clinical outcomes among patients treated in West Africa. Clinical and radiographic data of 57 patients (pts) who underwent surgical correction of post-TB kyphosis at a single site in West Africa between 2013 and 2018 (≥ 2-year follow-up in 36 pts, ≥ 1-year FU in 21 pts). Pre- and post-op SRS scores and radiographic outcomes were compared using Paired t test. 57 patients, 36M:21F. Mean age 19 (11-57years). 22/57 pts (39.3%) underwent pre-op halo gravity traction (HGT) for an average duration of 86days (8-144days). HGT pts had a higher baseline regional kyphosis (125.1 ± 20.9) compared to non-HGT pts (64.6 ± 31.8, p < 0.001). Post-HGT regional kyphosis corrected to 101.2 ± 23 (24° correction). 53 pts (92.9%) underwent posterior-only surgery and 4 (7.0%) combined anterior-posterior surgery. 39 (68.4%) had PVCR, 11 (19.3%) PSO, and 16 (28.1%) thoracoplasty. Intraoperative neuromonitoring (IOM) signal changes occurred in 23/57 pts (≈ 40%), dural tear in 5 pts (8.8%), pleural tear in 3 pts (5.3%), ureteric injury in 1 pt (1.7%), and vascular injury in 1 pt (1.7%). Post-op complications included four (7.0%) infection, three (5.3%) implant related, two (3.5%) radiographic (one PJK and one DJK), one (1.7%) neurologic, one (1.7%) wound problem, and two (3.5%) sacral ulcers. IOM changes were similar in the VCR (48.7%) and non-VCR (23.5%) pts, p > 0.05. Complication rates were similar among HGT and non-HGT groups. Significant improvements from baseline were seen in the average SRS Total and domains scores and radiographic measurements for patients who attained 2-year follow-up. PVCR ± HGT can provide safe and optimal correction in cases of severe post-TB kyphosis with good clinical and radiographic outcomes in underserved regions.

Source contributions in precipitation chemistry and analysis of atmospheric nitrogen deposition in a Sahelian dry savanna site in West Africa

Experimental data on precipitation chemistry were collected at a semi-arid savanna in Senegal (Dahra) in 2013, 2014 and 2017. The chemical composition of precipitation was analyzed for inorganic and organic ions, using ionic chromatography. The pH values of precipitation range from 4.50 to 8.50 with 89% of the samples having basic pH. The composition of precipitation was controlled by four source contributions: marine, terrigenous, biogenic, and organic acids emissions from vegetation. The terrigenous contribution was the highest accounting for 42% of the total annual Volume Weighted Mean ionic concentrations, due to the proximity of the Saharan desert, followed by the marine source representing 36%, due to the location of Dahra close to the Atlantic Ocean. Nitrogenous (N) contribution represents 16% of the mean annual total ionic charge, from biogenic sources and livestock crossing the site all year round. Finally, the lowest contribution is from organic acidity (5%), due to the low density of vegetation especially during the dry season. Wet deposition fluxes in Dahra for all compounds show larger values than at other Sahelian savanna sites. Dry N deposition in Dahra was also estimated by inferential method using gas concentration measurements and modeled dry deposition velocities. The total N deposition fluxes (wet plus dry) range from 3.80 to 4.81 kgN ha−1 yr−1, comparable to fluxes at other semi-arid savannas in Niger and Mali. Wet deposition contributed with 37–53% of the total N flux, suggesting that wet N deposition is equally important to dry deposition fluxes for direct N loading to savanna ecosystems in the Sahel, with a large contribution of reduced compounds. This study shows that Dahra presents a precipitation chemistry composition with characteristics close to those from other Sahelian sites, with however the specificity of being more influenced by the proximity of the Atlantic ocean and the presence of livestock year round.

Turnover, Passage Population Size and Flight Range of Juvenile Ruddy Turnstones at a Non-Estuarine Staging Site in the Netherlands

For five consecutive years (2001–2005), during a one-month period in August–September, we studied the turnover of juvenile Ruddy Turnstones Arenaria interpres at a tidal area along the Dutch coast, by colour-marking cohorts of migrants. Taking turnover into account revealed that 1.8–2.4 times as many juvenile birds used the area during their southward migration, compared to the numbers based on maximum counts. This larger estimate amounts to 35% of the number at which the 1% criterion of the Ramsar Convention is met, whereupon a wetland is designated as internationally important, with significant implications for conservation commitments. Presuming adult birds had the same turnover factor, adult birds contributed almost 70% to the 1% criterion during the same period. Autumn migration of juvenile Ruddy Turnstones was rapid, with more than 50% of individuals leaving within 4 days (95%-CI: 3.4–4.6). The mean mass at departure, as derived from median staging duration and mean body mass gain from recaptured birds (1.1 g/d), was 104.3 g (±10.3 SD). The mean potential flight range as calculated using the aerodynamic approach by Pennycuick was 1981 km (±717 SD), which suggests that juvenile birds that leave the area can cover short to medium distances at most. The fuel loads are sufficient to reach one of the four key wintering sites along the coast of France, but not the Banc d'Arguin in Mauretania, which is the first key wintering site in West Africa. By early October, 80% of the birds had left the study area. Our study shows the importance of a small tidal area during autumn migration and raises the question of whether a considerable number of comparable small stopover sites along the coast of Western Europe and West Africa are needed. More attention to the designation and the protection of such sites and the achievement of a network would have the potential to greatly support juvenile birds on their first journey south.

Characterization of complex vertebral transposition (gamma deformity) > 180 degrees: clinical and radiographic outcomes of halo gravity traction and vertebral column resection (VCR).

Prospective case series OBJECTIVE: Results of surgical treatment of complex vertebral transposition "Gamma Deformity" > 180 degrees with halo gravity traction (HGT) and vertebral column resection (VCR). We recently published a novel classification system for complex spine deformities of which complex vertebral transposition > 180 degrees (Gamma; type 3) was described. Halo gravity traction (HGT) has been shown to mitigate surgical risk in complex spine deformity correction and in some cases obviates the need for three-column osteotomy. However, we are not aware of report of its utilization in treating Gamma deformities with or without vertebral column resection (VCR). A consecutive series of 13 patients with Gamma deformity (GD) were prospectively enrolled at a single site in West Africa. Standard radiographs and 3D computerized tomography (CT) were done to assess coronal and sagittal vertebral transposition (CVT and SVT). The HGT with 50% of body weight was applied over several weeks followed by VCR. Demographics, operative data, radiographic parameters, and complications data were collected. 13 pts with GD underwent HGT for an avg of 110days prior to definitive surgery. Etiologies were Congenital-11 pts and Neurofibromatosis-2 pts. Average age: 17.8years; Pts were reviewed at 3months post-op and at minimum 2-year follow-up. Preop myelopathy was present in five patients. Pre-op CVT avg 75% and was corrected in all cases post-op. SVT avg 211deg and improved with HGT by 36% and corrected to 53deg (74% correction) post-op. Thoracic kyphosis avg -42deg and averaged 48deg post-op. Intra-op spinal cord monitoring (SCM) alerts occurred in 8 pts (61%). Post-operative LEM deficits occurred in 5 pts: 2 fully recovered by 3months and 2year follow-up, while the remaining 3 improved but had residual motor deficits at final follow-up. There was one post-operative mortality. The management of complex vertebral transposition (Gamma deformity) > 180 degrees with HGT prior to VCR is not only effective in some patients, but also associated with high SCM alerts and neurologic injury rates. Myelopathic patients with thoracic deformities are at higher risk of developing permanent neurologic deficits. Surgeons should be aware of this rare and unusual deformity and consider HGT and VCR bearing in mind the technical challenges and high complication rate.

Open-access platform to synthesize knowledge of ape conservation across sites.

Despite the large body of literature on ape conservation, much of the data needed for evidence-based conservation decision-making is still not readily accessible and standardized, rendering cross-site comparison difficult. To support knowledge synthesis and to complement the IUCN SSC Ape Populations, Environments and Surveys database, we created the A.P.E.S. Wiki (https://apeswiki.eva.mpg.de), an open-access platform providing site-level information on ape conservation status and context. The aim of this Wiki is to provide information and data about geographical ape locations, to curate information on individuals and organizations active in ape research and conservation, and to act as a tool to support collaboration between conservation practitioners, scientists, and other stakeholders. To illustrate the process and benefits of knowledge synthesis, we used the momentum of the update of the conservation action plan for western chimpanzees (Pan troglodytes verus) and began with this critically endangered taxon. First, we gathered information on 59 sites in West Africa from scientific publications, reports, and online sources. Information was compiled in a standardized format and can thus be summarized using a web scraping approach. We then asked experts working at those sites to review and complement the information (20 sites have been reviewed to date). We demonstrate the utility of the information available through the Wiki, for example, for studying species distribution. Importantly, as an open-access platform and based on the well-known wiki layout, the A.P.E.S. Wiki can contribute to direct and interactive information sharing and promote the efforts invested by the ape research and conservation community. The Section on Great Apes and the Section on Small Apes of the IUCN SSC Primate Specialist Group will guide and support the expansion of the platform to all small and great ape taxa. Similar collaborative efforts can contribute to extending knowledge synthesis to all nonhuman primate species.