8,703 results on '"Central Africa"'
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2. Pheromone traps and climate variations influence populations of Sahlbergella singularis (Hemiptera: Miridae) and associated damage of cocoa in Cameroon
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Mahot, Hermine C, Bagny-Beilhe, Leïla, Mahob, Raymond J, Begoudé, Aimé-Didier B, Kuate, Apollin Fotso, Membang, Gertrude, Ewane, Nathalie, Kemga, Adolph, Bilong, Charles FB, Hall, David R, Fiaboe, Komi KM, and Hanna, Rachid
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Zoology ,Ecology ,Biological Sciences ,Animals ,Hemiptera ,Pheromones ,Sex Attractants ,Cameroon ,Heteroptera ,Cacao ,Insect Control ,climate fluctuation ,mirid damage ,cocoa production ,central Africa ,Entomology - Abstract
Knowledge of insect pest ecology and biology is important for maximizing crop protection and reducing crop losses. Currently, we lack an efficient control program for the cocoa mirid Sahlbergella singularis Haglund (Hemiptera: Miridae), the principal insect pest of cocoa in West and Central Africa. A 2-yr study was conducted in 11 plantations across Ayos and Konye, two of the largest cocoa growing areas of Cameroon. We evaluated the effects of mirid sex pheromone and climatic variations on mirid population dynamics and their associated cocoa damage. Sex pheromone traps caught 1.5-fold higher mirids in Ayos than in Konye, with more overall counts in 2015 than in 2016. Cocoa pod counts were also significantly higher in 2015 than in 2016 and were negatively correlated with temperature and relative humidity. In both localities, mirid populations and associated cocoa pod damage were suppressed in plantations where sex pheromone traps were used. Damage incidence was positively correlated with mirid counts, confirming that the cocoa pod is the preferential site for mirid feeding and reproduction. As such, damage incidence could be used as proxy for comparative mirid population level due to the mirid's cryptic habit. Of the recorded weather variables, only relative humidity was correlated (negatively) with damage severity. Our data on the relationships between damage caused by mirids and their population dynamics and sex pheromone trap catches suggest that an effective control strategy using mass trapping could be developed for mirid management in cocoa plantations.
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- 2024
3. Detection and characterization of HIV‐1 group O and HIV‐2 in the Central African Republic.
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Moussa, Sandrine, Tagnouokam‐Ngoupo, Paul Alain, Tombette, Fabienne, Manirakiza, Alexandre, Boum, Yap, Vernet, Guy, Njouom, Richard, Belec, Laurent, Plantier, Jean‐Christophe, and Kfutwah, Anfumbom
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DIAGNOSTIC use of polymerase chain reaction , *DIAGNOSIS of HIV infections , *MOLECULAR epidemiology , *GENETIC variation , *BLOOD sampling - Abstract
The Central African Republic (CAR) is characterized by widespread HIV epidemic with notable prevalence and genetic diversity. We herein analysed the genetic diversity of atypical non‐M HIV‐1 strains. In‐house serotyping assays for variants of HIV‐1 (M, N, O, P) and HIV‐2 were used to test a biological collection of 6092 HIV‐seropositive blood samples collected between 2003 and 2014 at the Institut Pasteur de Bangui. Samples indicative of recombinant M/O groups, HIV‐2, or those that yield doubtful/negative results underwent further PCR tests and sequencing. We found six atypical HIV strains: specifically, three (0.05%) HIV‐1 group O strains (subtype H) detected in samples from 2005, 2008 and 2009, alongside three (0.05%) HIV‐2 strains (two group A and one group B) identified in samples from 2007 and 2009. HIV‐1/O strains showed a genetic link to Cameroon and Gabon strains. This study highlights the dominance of HIV‐1/M in the CAR's HIV epidemic over time and underscores the infrequent occurrence of HIV‐1 group O and HIV‐2 strains. These findings validate the efficacy of WHO‐recommended HIV testing protocols and emphasize the need for adaptive surveillance and management strategies to confront the complexities introduced by the genetic diversity of HIV strains. [ABSTRACT FROM AUTHOR]
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- 2024
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4. Provenance and depositional environment of the Mbam River overbank clay deposits, Central Africa: evidence from mineralogical and geochemical variations.
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Enock Embom, Christophe, Mbey, Jean Aimé, Onana, Vincent Laurent, and Ndjigui, Paul-Désiré
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X-ray fluorescence ,PLAGIOCLASE ,INFRARED spectroscopy ,ORTHOCLASE ,X-ray diffraction ,URANIUM - Abstract
This work permitted the understanding of processes in continental environments through the conditions of formation and deposition of alluvial clay materials in the Mbam Riverbanks (Central Africa). The Mbam River is the main tributary of the Sanaga River, one of the largest rivers in Central Africa. Twelve clay samples were collected from six wells, exhibiting different facies, and characterized using the Robinson-Köln pipetting, infrared spectroscopy, X-ray diffraction, and X-ray fluorescence. All the materials were classified as sandy clays. Their mineralogical assemblage is made of quartz, kaolinite, orthoclase, hematite/goethite, rutile, anorthite, and augite. The values for chemical, plagioclase, and mafic indices of alteration combined with those for Ba, Sr, and Rb/Sr ratio show that primary minerals like orthoclase, anorthite, and augite in source rocks are moderately altered. The studied materials are arkoses, wackes, shales, and Fe-Shales. Based on the index of compositional variability and on the SiO
2 /Al2 O3 ratio, the associated sediments are considered immature. They are, according to Cr, Ni, and SiO2 contents, Al2 O3 /TiO2 , Th/Sc, Th/Cr, and Cr/Ni ratios, and some binary provenance diagrams, from mafic, intermediate, and felsic sources. Values of the authigenic uranium, U/Th, V/Cr, and Ni/Co ratios permit to infer that they were deposited in an oxic environment. [ABSTRACT FROM AUTHOR]- Published
- 2024
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5. Differences in Thunderstorms' Ice Microphysics Between the Amazon and Central Africa Inferred From Spaceborne Passive Microwave and Radar Observations.
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Morvais, Florian and Liu, Chuntao
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PASSIVE radar ,ICE crystals ,ICE storms ,BRIGHTNESS temperature ,LAND surface temperature ,THUNDERSTORMS - Abstract
This study examines the differences related to microphysical properties of ice in thunderstorms over the Amazon and Congo Basin using the Precipitation Feature (PF) data sets derived from passive microwave and radar observations from the Tropical Rainfall Measuring Mission and Global Precipitation Mission Core Satellites. Analysis reveals that Amazon thunderstorms are likely composed of ice crystals smaller but more numerous than those in the Congo Basin, resulting in half as many flashes per PF on average in the Amazon, for similar Ice Water Content (IWC) or Area of 30 dBZ at −10°C (Acharge). The increase of the flash count following an increase of the IWC (Acharge) is only 72% (61%) as effective in the Amazon as it would be in the Congo Basin area. PFs with similar 30 dBZ radar echo top heights exhibit lower Brightness Temperatures (TBs) in the 85/89, 165, and 183 GHz frequencies over the Amazon, indicating more numerous smaller ice particles compared to those over the Congo Basin, which tend to show colder TBs at 37 GHz, possibly due to more numerous large graupel or hail particles. Comparisons of TBs in PFs with similar 30 dBZ echo top temperature between the Amazon and 3 × 3º global grids show that the median TB in Amazon is higher than that in most oceanic areas but is comparable to areas having high oceanic lightning activity (e.g., South Pacific Convergence Zone). It suggests that systems in the Amazon have similarities with maritime precipitation systems, yet with distinct characteristics indicative of land systems. Plain Language Summary: A comparison is made between Amazon (AM) and Congo Basin (CB) thunderstorms with similar reflectivity values seen by either TRMM or GPM, versus other variables that can help us understand the ice microphysics of these storms (IWC, area of 30 dBZ at −10C, Flash count, TBs). The radar reflectivity being driven by number and size (to the sixth power) of hydrometeors, the hypothesis is that for two storms with a same reflectivity value, one in AM and one in CB, the reflectivity value measured is driven by a higher concentration of large ice particles in CB (i.e., driven by size), while it is driven by a higher concentration of smaller ice particles in AM (i.e., driven by number). We quantify the lightning count difference between the two areas as a function of the amount of ice in the thunderstorm. It shows that AM produces significantly less lightning than CB on average for a similar ice content. Radiometers from TRMM and GPM are then used to compare the median TBs observed in the Amazon with the rest of the globe, to emphasize once again that AM is producing systems that are neither of land nor oceanic nature, but somewhere in the middle. Key Points: Amazonian systems are principally composed of smaller and more numerous ice crystalsIncreasing the Ice Water Content (IWC) and/or core size of thunderstorms in the Amazon demonstrates lower effectiveness in boosting lightning activityAmazonian systems present brightness temperatures unlike land or oceans but similar to oceanic regions with greater lightning activity [ABSTRACT FROM AUTHOR]
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- 2024
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6. Low-level circulation over Central Equatorial Africa as simulated from CMIP5 to CMIP6 models.
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Taguela, Thierry N., Pokam, Wilfried M., Dyer, Ellen, James, Rachel, and Washington, Richard
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ATMOSPHERIC models , *WESTERLIES , *VORTEX motion , *OCEAN , *TEMPERATURE - Abstract
We evaluate and compare the simulation of the main features (low-level westerlies (LLWs) and the Congo basin (CB) cell) of low-level circulation in Central Equatorial Africa (CEA) with eight climate models from Phase 6 of the Coupled Model Intercomparison Project (CMIP6) and the corresponding eight previous models from CMIP5. Results reveal that, although the main characteristics of the two features are reasonably well depicted by the models, they bear some biases. The strength of LLWs is generally overestimated in CMIP5 models. The overestimation is attributed to both divergent and rotational components of the total wind with the rotational component contributing the most in the overestimation. In CMIP6 models, thanks to a better performance in the simulation of both divergent and rotational circulation, LLWs are slightly less strong compared to the CMIP5 models. The improvement in the simulated divergent component is associated with a better representation of the near-surface pressure and/or temperature difference between the Central Africa landmass and the coastal Atlantic Ocean. Regarding the rotational circulation, and especially for HadGEM3-GC31-LL and BCC-CSM2-MR, a simulated higher 850 hPa pressure is associated with less pronounced negative vorticity and a better representation of the rotational circulation. Most CMIP5 models also overestimate the CB cell intensity and width in association with the simulated strength of LLWs. However, in CMIP6 models, the strength of key cell characteristics (intensity and width) are reduced compared to CMIP5 models. This depicts an improvement in the representation of the cell in CMIP6 models and this is associated with the improvement in the simulated LLWs. [ABSTRACT FROM AUTHOR]
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- 2024
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7. Ultra-Processed Foods and Nutritional Intake of Children and Adolescents from Cantagalo, São Tomé and Príncipe.
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Morais, Rita, Rodrigues, Mónica, Ferreira, Francisca, Barros, Renata, Padrão, Patrícia, Ortigão, Madalena, Tavares, Maria, and Moreira, Pedro
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PACKAGED foods ,METABOLIC disorders ,MIDDLE-income countries ,CROSS-sectional method ,LIFESTYLES ,IRON ,IRON in the body ,FOOD consumption ,DIETARY patterns ,RESEARCH funding ,T-test (Statistics) ,BODY mass index ,INCOME ,NUTRITIONAL assessment ,QUESTIONNAIRES ,LOGISTIC regression analysis ,FOOD handling ,SEX distribution ,NUTRITIONAL requirements ,VITAMIN B12 ,ZINC ,MANN Whitney U Test ,CHI-squared test ,AGE distribution ,DESCRIPTIVE statistics ,ODDS ratio ,DIETARY fiber ,SODIUM ,FOOD habits ,ANTHROPOMETRY ,CONFIDENCE intervals ,DATA analysis software ,COMPARATIVE studies ,HEALTH promotion ,LOW-income countries ,PHYSICAL activity ,EDUCATIONAL attainment ,REGRESSION analysis ,DISEASE risk factors - Abstract
Background: Globally, dietary patterns are shifting toward an increased consumption of ultra-processed foods, raising the risk of some metabolic and nutritional diseases from a young age. This trend is now also affecting low- and middle-income countries. Considering this, we aimed to assess the contribution of ultra-processed foods to total energy intake and their association with the nutritional intake of children and adolescents in Cantagalo, São Tomé and Príncipe. Methods: We conducted a cross-sectional study with a sample of 546 households. Data were collected on anthropometrics, sociodemographic characteristics, and lifestyle, including 24 h food recall questionnaires for children and adolescents. The reported foods were nutritionally assessed and categorized according to the NOVA classification to estimate the contribution of ultra-processed foods. Logistic regression models were used to estimate the magnitude of the associations between higher consumption of ultra-processed foods and nutritional intake, adjusting for confounders. Results: The contribution of ultra-processed foods to daily energy intake was 9.5% for girls and 8.5% for boys. Higher consumption of ultra-processed foods was significantly associated with a lower intake of fiber (OR = 0.932; 95%CI, 0.872–0.996), vitamin B12 (OR = 0.812; 95%CI, 0.668–0.985), and zinc (OR = 0.443; 95%CI, 0.308–0.639) and a higher intake of iron (OR = 1.479; 95%CI, 1.065–2.055) and sodium (OR = 1.001; 95%CI, 1.000–1.001), after adjusting for confounders. Conclusion: Higher consumption of ultra-processed foods was especially associated with a lower intake of fiber, vitamin B12, and zinc, and with a higher intake of iron. [ABSTRACT FROM AUTHOR]
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- 2024
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8. Diversity of Uses and Local Knowledge Associated with Wild African Plum Trees, Dacryodes edulis, Among Different Ethnic Groups in the Congo Basin.
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Mboujda, Franca Marcelle Meguem, Rimlinger, Aurore, Tientcheu, Marie-Louise Avana, Boupoya, Archange, Moupela, Christian, Tankou, Christopher, Duminil, Jérôme, and Carrière, Stéphanie M.
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PLUM ,ETHNIC groups ,LOCAL knowledge ,FOCUS groups ,ETHNOBOTANY - Abstract
Copyright of Economic Botany is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
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- 2024
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9. Three small species of shrews (Soricidae) from the Salonga National Park, Democratic Republic of the Congo, representing two new taxa and a new record.
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Hutterer, Rainer, Jocque, Merlijn, Mertens, Jan, Mpongo, Dieu M., and Mbende, Menard
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SHREWS , *NATIONAL parks & reserves , *SPECIES , *LAKES , *COLLECTIONS - Abstract
We report on a small collection of shrews from the central part of the Democratic Republic of Congo. Three taxa are recognized, of which a long-tailed and a middle-sized species of
Crocidura are described asC. salonga sp. nov. andC. binco sp. nov.Crocidura lwiroensis is recorded for the first time since its description from near Lake Tanganyika in 2013. [ABSTRACT FROM AUTHOR]- Published
- 2024
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10. Food Insecurity and Nutritional Inadequacy in Children and Adolescents of Basic Education Schools of Cantagalo District in São Tomé and Príncipe, Central Africa.
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Ferreira, Francisca, Tavares, Maria, Barros, Renata, Dias, Cláudia Camila, Morais, Rita, Ortigão, Madalena, Padrão, Patrícia, Rodrigues, Mónica, and Moreira, Pedro
- Abstract
Food insecurity (FI) is a critical socioeconomic and public health problem globally, particularly affecting children's nutritional status and development. This cross-sectional study aimed to assess the prevalence of nutritional inadequacy among children and adolescents in the Cantagalo district of São Tomé and Príncipe (STP), in Central Africa. It also assessed their households' FI situation and examined sociodemographic, anthropometric, and nutritional characteristics associated with severe FI. Data included 546 children/adolescents (51.8% males, aged 9–15 years) from the eight public basic education schools. A structured questionnaire provided sociodemographic data, while anthropometric measurements assessed nutritional status. Dietary intake data were gathered using a single 24 h dietary recall, and the adjusted prevalences of nutritional inadequacy were obtained using version 2.0 of the PC-Software for Intake Distribution Estimation (PC-SIDE
® ). The Household Food Insecurity Access Scale was used to assess FI, and households were classified as severely or non-severely food insecure. Multivariable binary logistic regression models adjusted for potential confounders identified factors related to FI. Children's/adolescents' thinness was exhibited in 34.1% of participants, and over 95% had inadequate intake of essential micronutrients, including iron. Notably, 73.7% were severely food insecure. A higher severity of FI was positively associated with a lower intake of iron and certain household head characteristics, such as being female or older, and negatively associated with having a home garden. [ABSTRACT FROM AUTHOR]- Published
- 2024
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11. Investigation of aerosol effects on diurnal cycle of precipitation amount, frequency and intensity over Central Africa.
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Matho Lontio, S. L., Komkoua Mbienda, A. J., Guenang, G. M., Demeko Yemih, P., Yan, Xing, Vondou, D. A., Ahrens, B., Dey, S., and Giorgi, F.
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MODIS (Spectroradiometer) , *ATMOSPHERIC aerosols , *FOURIER transforms , *SOLAR radiation , *FOURIER analysis - Abstract
Regional climate is affected by a wide variety of aerosols which modify through their radiative effects the precipitation distribution. In this article, the effects of aerosols, mainly dust aerosols on diurnal cycle of precipitation amount, frequency and intensity are investigated over central Africa by using the latest version of the Abdu Salam ICTP regional climate model coupled with the Community Land Model 4.5 as land surface scheme. Two sets of experiments have been conducted (one with aerosols interaction with dynamics and thermodynamics processes and another without this interaction) for a 10-year study period (2002–2011) and the Fourier transformation is used to study the 24-h cycle. In order to clearly understand spatial differences in RegCM experiments over central Africa, three subregions have been considered according to their land cover and climate characteristics. Our results indicate that the pattern of simulated aerosol optical depth (AOD) is well represented particularly northward of the study region compared to AOD from moderate resolution imaging spectroradiometer (MODIS) even if some differences in terms of magnitude are reported. The aerosols' effects on diurnal cycle are generally not similar to those found in the amplitude and phase. The result pointed out that over the Sahelian region, atmospheric aerosol in general and dust in particular always induced a positive effect on diurnal cycle (increase the magnitude of the cycle) of precipitation intensities and in precipitation amount and precipitation frequency as well. But, the change is opposite in terms of amplitude and peak time over some subregions. It appears that the forcing of aerosols in solar radiation as well as in latent heat flux leads to the changes in the amplitude of the precipitation amount during the DJF and JAS seasons particularly during daytime. The changes in amplitude of the precipitation frequency are not consistent even if the corresponding phase always tends to increase by up to 5 h. [ABSTRACT FROM AUTHOR]
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- 2024
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12. Rhizomic authoritarianism: power, biopolitics and transnational authoritarian practices in Cameroon.
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Ndjio, Basile
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INTERVENTION (International law) , *AUTHORITARIANISM , *INTERNATIONAL agencies , *HEGEMONY , *PRACTICAL politics - Abstract
This article discusses a rhizomic authoritarianism that generally operates through a complex network of connections. It provides a genealogical reading of the authoritarian rule in Cameroon, with a particular focus on the roles of France and China, using both primary and secondary sources. Specifically, it seeks to enlighten the complex processes through which a transnational authoritarianism has been established in Cameroon over the past six decades, as well as how the formation of strategic alliances between local political actors and international institutions has contributed to the normalization of authoritarian policies and practices that sometimes occur in transregional contexts. The paper's main argument is that the authoritarian system Cameroon has experienced since the late 1950s is rhizomatic in nature and is partially the result of the hegemonic interventions of international powers such as France and China in the country's politics and economy, as well as its development and modernization processes. [ABSTRACT FROM AUTHOR]
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- 2024
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13. Nationwide Inventory of Mosquitoes and the Distribution of Invasive Aedes (Stegomyia) albopictus (Skuse, 1894) on the Islands of Sao Tome and Principe in Central Africa.
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Yen, Tsai-Ying, Cheng, Chien-Fu, Tseng, Lien-Fen, Carvalho, Ronalg Mendes Costa d' Assunção, and Tsai, Kun-Hsien
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AEDES aegypti , *AEDES albopictus , *NATIVE species , *CYTOCHROME oxidase , *WASTE tires , *INSECT traps - Abstract
Simple Summary: Mosquito surveys conducted in the Democratic Republic of Sao Tome and Principe during 2000 to 2016 as a part of anti-malaria programs found the presence of four species of mosquitoes in the nation including Culex (Culex) poicilipes, Mansonia (Coquillettidia) annetti, Uranotaenia (Uranotaenia) alboabdominalis, and Uranotaenia (Uranotaenia) fraseri for the first time. Aedes albopictus (Skuse, 1894) was identified in 2015, and the follow-up survey confirmed that Aedes albopictus has become widespread across the nation. The larvae were predominant in artificial water-holding containers, with a positive rate up to 45.6% in used tires in Príncipe, while the native species, Aedes aegypti, preferred natural breeding sources. Phylogenetic analysis based on mitochondrial DNA revealed the introduced populations belonged to a clade involved in the worldwide spread of the species. Aedes albopictus is a public health threat due to its vectorial capacity for various arboviruses. Continuous vector surveillance and implication of interventions, such as source reduction to remove used tires, environmental management, and use of larvicides, were suggested. Aedes albopictus (Skuse, 1894), a mosquito originating in Asia, has been introduced to Africa since the 2000s. The mosquito is not only a nuisance but is capable of transmitting various arboviruses. The current study summarized our entomological surveys in the Democratic Republic of Sao Tome and Principe during 2000 to 2016. Adult mosquitoes were collected by sweep nets, human landing catches, and Centers for Disease Control (CDC) light traps, and the immatures were collected from water-filled habitats at 15 sentinel sites and reared to adulthood. Species identification was performed based on morphologic characteristics. Fragments of the cytochrome C oxidase subunit I (COI) and the Wolbachia surface protein (wsp) genes were amplified for mosquitoes collected in Principe. New records of four mosquito species were reported. Aedes albopictus was identified in 2015. The larvae were found distributed over the nation and were predominately in artificial water-holding containers (488/2698, 18.1%). The highest positive rate was observed in used tires in Príncipe (114/250, 45.6%). Mitochondrial DNA analysis revealed low genetic diversity among the invasive populations, but all tested specimens were superinfected by Wolbachia. The ability of Ae. albopictus to adapt to new environments and its involvement in disease transmission make the surveillance and control of this species particularly important. [ABSTRACT FROM AUTHOR]
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- 2024
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14. Gender and adolescent sexual and reproductive health and rights in West and Central Africa: New evidence and emerging gaps.
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Chimaraoke Izugbara, Kirabo Suubi, and Ingabire, Marie-Gloriose
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SERIAL publications ,HEALTH services accessibility ,REPRODUCTIVE health ,SEX distribution ,HUMAN sexuality ,HUMAN rights ,REPRODUCTIVE rights ,HEALTH promotion ,SEXUAL health ,WELL-being ,SOCIAL stigma - Published
- 2024
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15. Towards an integrated framework for sustainable sport tourism development in Central Africa.
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Nyikana, Siyabulela and Tichaawa, Tembi Maloney
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SPORTS tourism , *REGIONAL development , *SUSTAINABLE tourism , *TOURISM , *EVENT tourism - Abstract
This study develops an integrated framework for the development of sport tourism, using Cameroon as a case study. A qualitative research approach was used to critically analyse existing sport tourism frameworks in the Global North and Global South contexts to draw key comparisons for the contrasting economies therein. Documentary analysis with in-depth semi-structured interviews with stakeholders in sport and tourism was conducted. Findings reveal that the sport tourism sector has great potential to make a meaningful socioeconomic contribution to economies in the region through interlinkages. For sustainable sports tourism to contribute to government priorities around regional development, global competitiveness, infrastructural development and community development, an integrated framework is needed. The study has implications for policy and planning. [ABSTRACT FROM AUTHOR]
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- 2024
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16. An overview of artemisinin-resistant malaria and associated Pfk13 gene mutations in Central Africa.
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Milong Melong, Charlotte Sabine, Peloewetse, Elias, Russo, Gianluca, Tamgue, Ousman, Tchoumbougnang, Francois, and Paganotti, Giacomo Maria
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Malaria caused by Plasmodium falciparum is one of the deadliest and most common tropical infectious diseases. However, the emergence of artemisinin drug resistance associated with the parasite’s Pfk13 gene, threatens the public health of individual countries as well as current efforts to reduce malaria burdens globally. It is of concern that artemisinin-resistant parasites may be selected or have already emerged in Africa. This narrative review aims to evaluate the published evidence concerning validated, candidate, and novel Pfk13 polymorphisms in ten Central African countries. Results show that four validated non-synonymous polymorphisms (M476I, R539T, P553L, and P574L), directly associated with a delayed therapy response, have been reported in the region. Also, two Pfk13 polymorphisms associated to artemisinin resistance but not validated (C469F and P527H) have been reported. Furthermore, several non-validated mutations have been observed in Central Africa, and one allele A578S, is commonly found in different countries, although additional molecular and biochemical studies are needed to investigate whether those mutations alter artemisinin effects. This information is discussed in the context of biochemical and genetic aspects of Pfk13, and related to the regional malaria epidemiology of Central African countries. [ABSTRACT FROM AUTHOR]
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- 2024
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17. Seasonal variations in rain cells propagation over Central Africa and association with diurnal rainfall regimes.
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Camberlin, Pierre, Moron, Vincent, Philippon, Nathalie, Mengouna, François Xavier, and Vondou, Derbetini A.
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MESOSCALE convective complexes , *DIURNAL variations of rainfall , *RAINFALL , *SEASONS - Abstract
Three‐hourly data from two satellite rainfall estimates products, PERSIANN and TMPA, are analysed to document the seasonal patterns of diurnal rainfall distribution over the Congo Basin and neighbouring areas. PERSIANN data for 2001–2017, at a one‐hour time‐scale, are further used to identify rain cells (≥4 mm·h−1) in an attempt to explain the diurnal rainfall variations. Over land areas, an afternoon rainfall maximum is clearly shown, but over much of the region only a minor part of the rains (20%–30%) falls in the wettest 3‐h period. Substantial rains (often 50%–60%) occur in the evening and at night, as a progressively delayed peak from east to west, but a seasonal change is found in the meridional propagation of the peak diurnal rainfall, in a south‐westerly direction in January, and a north‐westerly direction in July. Rain cells have prominent genesis areas west of high terrain, but can develop over most regions, with a peak genesis time slightly ahead the diurnal phase of the rains. The size, mean lifetime and mean rainfall intensity of the rain cells are strongly related to each other and display a semi‐annual cycle not fully in phase with the seasonal cycle of the rains. The mean rain cell propagation speed (6.7 m·s−1) is much lower than in previous studies, which focused on mesoscale convective systems. Rain cells which have a longer lifetime move much faster, the mean speed of those lasting less than 6 h being half that of those lasting at least 24 h. Most (86%) of the mobile rain cells propagate westward, but the meridional component of their propagation shows an annual cycle (southward in austral summer, northward in boreal summer) which matches the mid‐tropospheric winds and explains the seasonal changes in the diurnal rainfall peak. [ABSTRACT FROM AUTHOR]
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- 2024
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18. Environmental variation predicts patterns of genomic variation in an African tropical forest frog.
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Miller, Courtney A., Taboue, Geraud C. Tasse, Fokam, Eric B., Morgan, Katy, Ying Zhen, Harrigan, Ryan J., Le Underwood, Vinh, Ruegg, Kristen, Clee, Paul R. Sesink, Ntie, Stephan, Mickala, Patrick, Mboumba, Jean Francois, Fuller, Trevon, Zimkus, Breda M., Smith, Thomas B., and Anthony, Nicola M.
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TROPICAL forests ,FROGS ,ATMOSPHERIC models ,GENE frequency ,GRAPHICAL projection ,SPECIES diversity - Abstract
Central African rainforests are predicted to be disproportionately affected by future climate change. How species will cope with these changes is unclear, but rapid environmental changes will likely impose strong selection pressures. Here we examined environmental drivers of genomic variation in the central African puddle frog (Phrynobatrachus auritus) to identify areas of elevated environmentally-associated turnover. We also compared current and future climate models to pinpoint areas of high genomic vulnerability where allele frequencies will have to shift the most in order to keep pace with future climate change. Neither physical landscape barriers nor the effects of past Pleistocene refugia influenced genomic differentiation. Alternatively, geographic distance and seasonal aspects of precipitation are the most important drivers of SNP allele frequency variation. Patterns of genomic differentiation coincided with key ecological gradients across the forest-savanna ecotone, montane areas, and a coastal to interior rainfall gradient. Areas of greatest vulnerability were found in the lower Sanaga basin, the southeastern region of Cameroon, and southwest Gabon. In contrast with past conservation efforts that have focused on hotspots of species richness or endemism, our findings highlight the importance of maintaining environmentally heterogeneous landscapes to preserve genomic variation and ongoing evolutionary processes in the face of climate change. [ABSTRACT FROM AUTHOR]
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- 2024
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19. Performance‐based evaluation of NMME and C3S models in forecasting the June–August Central African rainfall under the influence of the South Atlantic Ocean Dipole.
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Nana, Hermann N., Tamoffo, Alain T., Kaissassou, Samuel, Djiotang Tchotchou, Lucie A., Tanessong, Roméo S., Kamsu‐Tamo, Pierre H., Kenfack, Kevin, and Vondou, Derbetini A.
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GEOPHYSICAL fluid dynamics , *FORECASTING , *ATMOSPHERIC models , *ATMOSPHERIC circulation , *RAINFALL , *OCEAN , *SOUTHERN oscillation ,EL Nino - Abstract
In this study, hindcasts from eight Copernicus Climate Change Service (C3S) and three North American Multi‐Model Ensemble (NMME) operational seasonal forecast systems, based on dynamical climate models, are employed to investigate the influence of the South Atlantic Ocean Dipole (SAOD) on the predictive skill of Central Africa (CA) rainfall. The focus is primarily on the June–July–August season for 1993–2016. The findings reveal that, when regionally averaged, all models exhibit positive skill in predicting CA rainfall, except for the Geophysical Fluid Dynamics Laboratory (GFDL‐SPEAR) model. Notably, there are significant spatial variations in skill across different regions. Model performance is particularly low (high) in the Central African Republic and Congo Basin (Gabon and Chad) and tends to deteriorate with increasing lead‐time. Models that demonstrate a strong connection between SAOD and CA rainfall tend to exhibit better predictive skills in forecasting rainfall, in contrast to models with weaker connections. This leads to a significant in‐phase relationship between the predictive skills of rainfall and the strength of the SAOD–rainfall connection among the models. Furthermore, the atmospheric circulation responding to SST forcing associated with the El Niño–Southern Oscillation exerts a significant influence on the robust atmospheric circulation associated with the climatological mean of SST over the SAO. This suggests that mean state bias in the SAO/equatorial Pacific region plays a role in modulating the strength of the simulated SAOD–CA rainfall connection and, consequently, the prediction skill of CA rainfall. In general, both NMME and C3S models appear to be valuable tools capable of providing essential seasonal information several months in advance. These insights can aid decision‐makers in the region in making informed decisions regarding adaptation and mitigation measures. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
20. Export diversification and income inequality in Central Africa: An analysis of the employment channel.
- Author
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Tchitchoua, Jean, Tsomb Tsomb, Etienne Inedit Blaise, and Madomo, Johny
- Subjects
- *
INCOME inequality , *EXPORTERS , *WOMEN'S employment , *RANDOM effects model , *LEAST squares , *EMPLOYMENT , *WAGE increases - Abstract
This paper analyses the effect of export diversification on income inequality in Central Africa through the employment channel. The sample consists of 9 countries over the period 2000–2019. A quadratic regression is applied to a panel data model using the random effect and the two stages least squares methods. The results show that export diversification increases income inequality in Central Africa. However, this effect is non-linear with the form of an inverted U. Increasing the number of wage workers reduces the marginal effect of export diversification on income inequality while increasing the number of unpaid workers increases this effect. Moreover, diversification is less likely to reduce income inequality when it increases male employment than when it increases female employment. The effect of diversification on income inequality remains non-linear in an inverted U-shape for CEMAC countries' members (CEMAC: Economic and Monetary Community of Central African States) and oil-producing countries, while it is non-linear in a U-shape for non-CEMAC countries and non-oil-producing countries. We recommend that Central African countries promote the diversification of exports while encouraging new productive activities to generate more paid jobs and to favor female employment. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
21. Response of regional circulation features to the Indian Ocean dipole and influence on Central Africa climate.
- Author
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Moihamette, Foupouapegnigni, Pokam, Wilfried M., Diallo, Ismaila, and Washington, Richard
- Subjects
- *
OCEAN dynamics , *ATMOSPHERIC circulation , *OCEAN , *WESTERLIES , *MOISTURE - Abstract
The time-varying September-November relationship between the Indian Ocean Dipole (IOD) and Central African (CA) rainfall has strengthened since the 1990s, implying an increasing IOD influence over CA rainfall. Using observational and reanalysis datasets covering the 1980–2016 period, this study examines the CA circulation response associated with the Indian Ocean dynamics during the September-December IOD events, since this circulation constitutes a key moisture transport feature for CA rainfall variability. The results show that during positive IOD events (pIOD), the moisture transport drivers over CA and the Indian Ocean (IO) are synchronous, leading to an increase in CA rainfall, whereas the reverse pattern is observed during negative IOD events (nIOD). The equatorial easterly (westerly) moisture transport driven by the anticyclonic (cyclonic) circulation in the northern tropical IO and the weakening (intensification) of the African Easterly Jet's northern component (AEJ-N), leads to an increase (decrease) in CA rainfall during pIOD (nIOD). Warm (cold) SST anomalies in the eastern Indian Ocean during nIOD (pIOD) event, intensify (weaken) the large-scale upward motion, strengthening (weakening) the cyclonic circulation in the mid-troposphere, thus favoring a significant westerly (easterly) circulation. The AEJ-N weakening during pIOD events is associated with a strengthening of the meridional pressure gradient and a westward shift in the Saharan high location at the AEJ-N's northern edge. The results also reveal a significant influence of the Atlantic during pIOD events, induced by its teleconnection with the IO, whose effects are more modulated by the IOD's western pole warming than by the IOD-related SST gradient. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
22. Parasitism of the whitefly Bemisia tabaci by aphelinid parasitoids on cassava across five agro-ecological zones of Cameroon
- Author
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Tize, Isaac, Nukenine, Elias Nchiwan, Kuate, Apollin Fotso, Fotio, Armand Doumtsop, Nanga, Samuel Nanga, Ajebesone, Francis Ngome, Kulakow, Peter, Kumar, P Lava, Fiaboe, Komi Kouma Mokpokpo, and Hanna, Rachid
- Subjects
Plant Biology ,Agricultural ,Veterinary and Food Sciences ,Crop and Pasture Production ,Biological Sciences ,Biological control ,Host -plant resistance ,Encarsia lutea ,Encarsia sophia ,Central Africa ,Entomology ,Crop and pasture production ,Plant biology - Published
- 2023
23. Enhancing scientific and community capacity to conserve Central African Lepidoptera
- Author
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Dongmo, Michel AK, Hanna, Rachid, and Bonebrake, Timothy C
- Subjects
Biological Sciences ,Ecology ,Life on Land ,Peace ,Justice and Strong Institutions ,Lepidoptera ,Central Africa ,Conservation actions ,Funding ,Museum collection ,Environmental Sciences ,Agricultural and Veterinary Sciences ,Zoology ,Environmental management - Abstract
Research on the ecology and conservation of Lepidoptera (and other species) has historically neglected tropical diversity – but the Lepidoptera of tropical Africa have been particularly understudied. Central Africa represents a major centre of biodiversity for butterflies, moths and other taxa but major threats including habitat loss, habitat degradation/ disturbance and climate change are threatening their persistence. Additionally, a range of obstacles to research and conservation are apparent in Central Africa, including major socioeconomic disparity, persistent armed conflicts, corruption, and a lack of local resources (e.g., funding and museums). Here we outline the history of research on the butterflies of Central Africa and highlight the importance of further conservation efforts in maintaining the biodiversity of Lepidoptera and other understudied insects in the region. Proactive measures acknowledging the prevailing regional challenges must be taken immediately. Among the major recommendations, we suggest: 1) enhancing museum collections, 2) facilitating strong scientific collaboration that enhances local capacity, 3) ensuring that funded projects are not disrupted by corruption, and 4) working to advance the socioeconomic status of local communities. Potential for scientific and community advancement in the region is substantial if investment and research efforts are targeted effectively.
- Published
- 2023
24. Extremes events and socio-economic impacts in central Africa: a CMIP6-based analysis of projections
- Author
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Ebedi-Nding, Dorcas Daniella, Tamoffo, Alain T., and Mouassom, Fernand L.
- Published
- 2024
- Full Text
- View/download PDF
25. Evaluation of centralised and decentralised models of care during the 2020 Ebola Virus Disease outbreak in Equateur Province, Democratic Republic of the Congo: A brief report [version 2; peer review: 1 approved, 1 approved with reservations]
- Author
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Emmanuel Lampaert, Justus Nsio Mbeta, Divya Nair, Maria Mashako, Anja De Weggheleire, Armand Sprecher, Rebecca M. Coulborn, and Steve Ahuka-Mundeke
- Subjects
Brief Report ,Articles ,Viral Haemorrhagic Fever ,Central Africa ,SORT IT ,Outbreak ,Epidemic response ,Decentralized care ,Operational Research ,Ebola - Abstract
Background Traditionally in the Democratic Republic of the Congo (DRC), centralised Ebola treatment centres (ETCs) have been set exclusively for Ebola virus disease (EVD) case management during outbreaks. During the 2020 EVD outbreak in DRC’s Equateur Province, existing health centres were equipped as decentralised treatment centres (DTC) to improve access for patients with suspected EVD. Between ETCs and DTCs, we compared the time from symptom onset to admission and diagnosis among patients with suspected EVD. Methods This was a cohort study based on analysis of a line-list containing demographic and clinical information of patients with suspected EVD admitted to any EVD health facility during the outbreak. Results Of 2359 patients with suspected EVD, 363 (15%) were first admitted to a DTC. Of 1996 EVD-suspected patients initially admitted to an ETC, 72 (4%) were confirmed as EVD-positive. Of 363 EVD-suspected patients initially admitted to a DTC, 6 (2%) were confirmed and managed as EVD-positive in the DTC. Among all EVD-suspected patients, the median (interquartile range) duration between symptom onset and admission was 2 (1-4) days in a DTC compared to 4 (2-7) days in an ETC (p Conclusions Since
- Published
- 2024
- Full Text
- View/download PDF
26. Evaluation of centralised and decentralised models of care during the 2020 Ebola Virus Disease outbreak in Equateur Province, Democratic Republic of the Congo: A brief report [version 1; peer review: awaiting peer review]
- Author
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Emmanuel Lampaert, Justus Nsio Mbeta, Divya Nair, Maria Mashako, Anja De Weggheleire, Armand Sprecher, Rebecca M. Coulborn, and Steve Ahuka-Mundeke
- Subjects
Brief Report ,Articles ,Viral Haemorrhagic Fever ,Central Africa ,SORT IT ,Outbreak ,Epidemic response ,Decentralized care ,Operational Research ,Ebola - Abstract
Background Traditionally in the Democratic Republic of the Congo (DRC), centralised Ebola treatment centres (ETCs) have been set exclusively for Ebola virus disease (EVD) case management during outbreaks. During the 2020 EVD outbreak in DRC’s Equateur Province, existing health centres were equipped as decentralised treatment centres (DTC) to improve access for patients with suspected EVD. Between ETCs and DTCs, we compared the time from symptom onset to admission and diagnosis among patients with suspected EVD. Methods This was a cohort study based on analysis of a line-list containing demographic and clinical information of patients with suspected EVD admitted to any EVD health facility during the outbreak. Results Of 2359 patients with suspected EVD, 363 (15%) were first admitted to a DTC. Of 1996 EVD-suspected patients initially admitted to an ETC, 72 (4%) were confirmed as EVD-positive. Of 363 EVD-suspected patients initially admitted to a DTC, 6 (2%) were confirmed and managed as EVD-positive in the DTC. Among all EVD-suspected patients, the median (interquartile range) duration between symptom onset and admission was 2 (1-4) days in a DTC compared to 4 (2-7) days in an ETC (p Conclusions Since
- Published
- 2024
- Full Text
- View/download PDF
27. Characterization of adaptation mechanisms in sorghum using a multireference back-cross nested association mapping design and envirotyping.
- Author
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Garin, Vincent, Diallo, Chiaka, Tékété, Mohamed Lamine, Théra, Korotimi, Guitton, Baptiste, Dagno, Karim, Diallo, Abdoulaye G, Kouressy, Mamoutou, Leiser, Willmar, Rattunde, Fred, Sissoko, Ibrahima, Touré, Aboubacar, Nébié, Baloua, Samaké, Moussa, Kholovà, Jana, Frouin, Julien, Pot, David, Vaksmann, Michel, Weltzien, Eva, and Témé, Niaba
- Subjects
- *
SOILS , *PHYSIOLOGICAL adaptation , *ECOLOGY , *RESEARCH funding , *CONSERVATION of natural resources , *GENOMICS , *CLIMATOLOGY , *GENE mapping , *EDIBLE plants , *GENES , *WEATHER , *TEMPERATURE , *GENETICS , *TIME , *GENOMES - Abstract
Identifying the genetic factors impacting the adaptation of crops to environmental conditions is of key interest for conservation and selection purposes. It can be achieved using population genomics, and evolutionary or quantitative genetics. Here we present a sorghum multireference back-cross nested association mapping population composed of 3,901 lines produced by crossing 24 diverse parents to 3 elite parents from West and Central Africa-back-cross nested association mapping. The population was phenotyped in environments characterized by differences in photoperiod, rainfall pattern, temperature levels, and soil fertility. To integrate the multiparental and multi-environmental dimension of our data we proposed a new approach for quantitative trait loci (QTL) detection and parental effect estimation. We extended our model to estimate QTL effect sensitivity to environmental covariates, which facilitated the integration of envirotyping data. Our models allowed spatial projections of the QTL effects in agro-ecologies of interest. We utilized this strategy to analyze the genetic architecture of flowering time and plant height, which represents key adaptation mechanisms in environments like West Africa. Our results allowed a better characterization of well-known genomic regions influencing flowering time concerning their response to photoperiod with Ma6 and Ma1 being photoperiod-sensitive and the region of possible candidate gene Elf3 being photoperiod-insensitive. We also accessed a better understanding of plant height genetic determinism with the combined effects of phenology-dependent (Ma6) and independent (qHT7.1 and Dw3) genomic regions. Therefore, we argue that the West and Central Africa-back-cross nested association mapping and the presented analytical approach constitute unique resources to better understand adaptation in sorghum with direct application to develop climate-smart varieties. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
28. THE EFFICIENCY OF FOREST MANAGEMENT PRACTICES IN CAMEROON 30 YEARS AFTER THE ADOPTION OF A NEW LEGAL FRAMEWORK.
- Author
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A., Ngoungoure Manjeli, A. B., Biwolé, K., Daïnou, F., Tosso, J. D., Mendomo Biang, F., Choula, and S., Bobo Kadiri
- Subjects
- *
SUSTAINABILITY , *FOREST policy , *RESOURCE exploitation , *LOGGING , *POPULATION dynamics , *FOREST management - Abstract
Practices in sustainable forest management are ruled by national forest policies. Legal standards of forest management applied in Central African region display increasing risks of long-term depletion of timber resources. This review aims to assess the effectiveness of sustainable logging practices by highlighting the strengths and weaknesses of the forest management rules applied in Cameroon. The management of the populations of timber tree species is based on population dynamics traits and on measures imposed by national forestry policies. Before any exploitation in natural forest concessions, a management plan must be approved to define the various activities and the potential impacts on the forest. Despite many relevant principles, nearly three decades of forest management in Cameroon have exhibited gaps that need to be addressed in the legal standards of forest management. Proposals for improvement relate to procedures for determining the recovery rate and how considerations on density and seed tree populations should be included into the legal management policies. These suggestions depend on the knowledge of demographic dynamics and the reproductive ecology of the timber taxa as well as a more rapid integration of scientific results into the legal forest management standards. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
29. Mercenarios blancos entre el Congo y Nigeria: neocolonialismo y contrainsurgencia en África Central durante la Guerra Fría, 1960-1970.
- Author
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Alonso Ibarra, Miguel and Alegre Lorenz, David
- Subjects
NEOCOLONIALISM ,GEOPOLITICS ,INTERNATIONAL relations ,RECRUITING & enlistment (Armed Forces) ,BISHOPS - Abstract
Copyright of Ayer: Revista de Historia Contemporánea is the property of Asociacion de Historia Contemporanea and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2024
- Full Text
- View/download PDF
30. Paying for sea turtles as incentive for conservation in São Tomé and Príncipe.
- Author
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Ferreira, Rogério L.
- Subjects
TURTLE conservation ,SEA turtles ,WELL-being ,TURTLES - Abstract
Although incentives for sea turtle conservation are widespread, few interventions involving direct payments to individuals for releasing captured turtles have been documented, limiting valuable learning opportunities for conservation practitioners and hindering the development of the field.This study reports on two initiatives involving the purchase of live sea turtles from citizens in São Tomé and Príncipe, highlighting the inappropriateness of this measure in impoverish locations by unveiling unplanned consequences and their implications for future conservation efforts.To ensure effectiveness and lasting behaviour change of stakeholders, the design of conservation experiments in economically disadvantaged areas or marginalized communities, particularly those conducted by outsiders, should incorporate an ethnographic component and consider the impacts on the well‐being of local people. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
31. Between Economic Nationalism and Liberalization: Ideas of Development and the Neoliberal Moment in Mobutu's Congo, 1965–74.
- Author
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Vale, Peter
- Subjects
- *
NATIONALISM , *FINANCIAL liberalization , *NEOLIBERALISM , *INVESTORS , *INTELLECTUALS - Abstract
In January 1967, under the infamous military head Joseph-Désiré Mobutu, the Democratic Republic of Congo nationalized its mining industry based on anticolonial rhetoric of "economic sovereignty." Only two years later, the same Mobutu government welcomed foreign companies and investors with open arms to the inaugural Foire Internationale de Kinshasa. Even at this crucial postcolonial moment when ideas of economic independence and self-sufficiency had become so highly valued, an attachment to — even affinity towards — foreign capital persisted throughout Congolese politics. This article explores the political and intellectual tensions that arose from the postcolonial utilization of foreign capital for state consolidation and synthesizes these contradictions into a broader understanding of early development approaches in Mobutu's Congo. In contrast to those who have framed the Congolese leader's ideology as a rearticulation of colonial logics or the authoritarian whims of an individual, I argue that these early notions of Mobutist development should be understood as a kind of "worldmaking," emerging from an anticolonial ideology that asserted Congo's economic sovereignty while simultaneously inserting itself into the global streams of finance. By tracing the Mobutu government's fluctuating relationship to foreign finance, this research offers a longer history of the "neoliberal moment" in Congo — one in which the intellectual underpinnings for liberalization had percolated in Congolese nationalist politics for several decades. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
32. Mwene Muji: A Medieval Empire in Central Africa?
- Author
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Thornton, John
- Subjects
- *
HISTORIOGRAPHY , *ORAL tradition , *ANTIQUITIES , *CARTOGRAPHY - Abstract
Although the Lower Kasai was identified by Jan Vansina as a likely center for highly complex societies, he failed to recognize that sixteenth-century sources had mentioned the Empire of Mwene Muji as a large polity in that region. Studying the well known and recently discovered literature on West Central Africa, as well as a critical study of oral tradition, shows considerable evidence for the antiquity and existence of Mwene Muji. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
33. 'What sort of thing is an elephant?' Reviewing the evidence for a 'generic' MSA in Central Africa.
- Author
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Taylor, Nicholas
- Subjects
- *
MESOLITHIC Period - Abstract
Despite a 100-year scientific research legacy, the Middle Stone Age (MSA) record of Central Africa remains poorly known and is stubbornly peripheral to debates on the timing, pace and nature of technological change in relation to the evolutionary origins of Homo sapiens. The MSA Lupemban industry is often characterised as the singular representative of the MSA across the region, but the details of its chrono-stratigraphic relationship with preceding and particularly succeeding industries are still unclear. To archaeologists working with longer records on the margins of Central Africa, the Lupemban has been principally conceptualised in relation to the preceding Acheulean/MSA transition, and as a specifically early MSA, late Middle Pleistocene (MIS 7?) entity. Evidence presented here suggests that it was subsequently replaced or graded into a 'generic' or 'undifferentiated' MSA, or into a sub-regional 'Lupembo-Tshitolian' industry. By contrast, the shorter records of Lowland Atlantic Central Africa mean that there archaeologists have instead reported the Lupemban as a probably late-persisting Upper Pleistocene (MIS 3/2?) industry that temporally abuts the Later Stone Age (LSA) without any 'generic MSA'. This paper reviews key sequences from the periphery and core of Central Africa and explores these differing perspectives to address the reality and complexities of a Central African 'generic MSA'. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
34. Availability of the current and future water resources in Equatorial Central Africa: case of the Nyong forest catchment in Cameroon.
- Author
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Ebodé, Valentin Brice, Onana, Jean Yannick Ngono, Dzana, Jean Guy, Amougou, Joseph Armathé, Batha, Romain Armand Soleil, Boyomo, Thomas Magloire Souga, and Mbeih, Gaston Evarice Ndjela
- Subjects
WATER currents ,WATER supply ,WATER management ,LAND cover ,LAND use ,DROUGHTS - Abstract
To anticipate disasters (drought, floods, etc.) caused by environmental forcing and reduce their impacts on its fragile economy, sub-Saharan Africa needs a good knowledge of the availability of current water resources and reliable hydroclimatic forecasts. This study has an objective to quantify the availability of water resources in the Nyong basin and predict its future evolution (2024–2050). For this, the SWAT (Soil and Water Assessment Tool) model was used. The performance of this model is satisfactory in calibration (2001–2005) and validation (2006–2010), with R
2 , NSE, and KGE greater than 0.64. Biases of − 11.8% and − 13.9% in calibration and validation also attest to this good performance. In the investigated basin, infiltration (GW_RCH), evapotranspiration (ETP), surface runoff (SURQ), and water yield (WYLD) are greater in the East, probably due to more abundant rainfall in this part. The flows and sediment load (SED) are greater in the middle zone and in the Southwest of the basin, certainly because of the flat topography of this part, which corresponds to the valley floor. Two climate models (CCCma and REMO) predict a decline in water resources in this basin, and two others (HIRHAM5 and RCA4) are the opposite. However, based on a statistical study carried out over the historical period (2001–2005), the CCCma model seems the most reliable. It forecasts a drop in precipitation and runoff, which do not exceed − 19% and − 18%, respectively, whatever the emission scenario (RCP4.5 or RCP8.5). Climate variability (CV) is the only forcing whose impact is visible in the dynamics of current and future flows, due to the modest current (increase of + 102 km2 in builds and roads) and future (increase of + 114 km2 in builds and roads) changes observed in the evolution of land use and land cover (LULC). The results of this study could contribute to improving water resource management in the basin studied and the region. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
35. Changes in climate, vegetation cover and vegetation composition affect runoff generation in the Gulf of Guinea Basin.
- Author
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Nkiaka, Elias and Okafor, Gloria Chinwendu
- Subjects
GROUND vegetation cover ,FOREST canopies ,RUNOFF ,CLIMATE change ,ELASTICITY (Economics) - Abstract
Although considerable effort has been deployed to understand the impact of climate variability and vegetation change on runoff in major basins across Africa, such studies are scarce in the Gulf of Guinea Basin (GGB). This study combines the Budyko framework and elasticity concept along with geospatial data to fill this research gap in 44 nested sub‐basins in the GGB. Annual rainfall from 1982 to 2021 show significant decreasing and increasing trends in the northern and southern parts of the GGB, respectively. Annual potential evapotranspiration (PET) also shows significant increasing trends with higher magnitudes observed in the northern parts of the GGB. Changing trends in climate variables corroborates with shift to arid and wetter conditions in the north and south, respectively. From 2000 to 2020 vegetation cover estimated using enhanced vegetation index (EVI) shows significant increasing trends in all sub‐basins including those experiencing a decline in annual rainfall. Vegetation composition measured using vegetation continuous fields (VCFs) from 2000 to 2020 show an increase in tree canopy cover (TC), a decline in short vegetation cover and marginal changes in bare ground cover (BG). Elasticity coefficients show that a 10% increase in annual rainfall and PET may lead to a 33% increase and 24% decline in runoff, respectively. On the other hand, a 10% increase in EVI may lead to a 4% decline in runoff while a 10% increase in TC, SV and BG may reduce runoff by 4% and increase runoff by 3% and 2%, respectively. Even though changes are marginal, decomposing vegetation into different parameters using EVI and VCFs may lead to different hydrological effects on runoff which is one of the novelties of this study that may be used for implementing nature‐based solutions. The study also demonstrates that freely available geospatial data together with analytical methods are a promising approach for understanding the impact of climate variability and vegetation change on hydrology in data‐scarce regions. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
36. Science Advisory to Governments and Regional/Sub-Regional Organizations in West and Central Africa.
- Author
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Mbah, David A., Diallo, Madiagne, and Guewo-Fokeng, Magellan
- Subjects
SCIENTISTS in government ,COLONIES ,IMPERIALISM ,SUSTAINABLE development - Abstract
Copyright of Cameroon Academy of Sciences Journal is the property of Cameroon Academy of Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2024
- Full Text
- View/download PDF
37. Science Diplomacy in West and Central Africa: State, Trends and Patterns.
- Author
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Mbah, David A., Diallo, Madiagne, and Guewo-Fokeng, Magellan
- Subjects
SCIENCE ,DIPLOMACY ,COLONIES ,IMPERIALISM - Abstract
Copyright of Cameroon Academy of Sciences Journal is the property of Cameroon Academy of Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2024
- Full Text
- View/download PDF
38. Description of two new species of Turanogryllini crickets (Orthoptera, Gryllidae, Gryllinae) from Cameroon, with identification keys for African species
- Author
-
Nyobe, Philene Corinne Aude Um, Robillard, Tony, Kekeunou, Sévilor, Ma, Libin, Nzike, Marcelle Mbadjoun, Bilong, Charles Felix Bilong, and Pensoft Publishers
- Subjects
Afrique centrale ,bioecologie ,bioecology ,Central Africa ,Taxonomie ,taxonomy ,Turanogryllini - Published
- 2022
39. Evaluation of centralised and decentralised models of care during the 2020 Ebola Virus Disease outbreak in Equateur Province, Democratic Republic of the Congo: A brief report [version 2; peer review: 2 approved]
- Author
-
Steve Ahuka-Mundeke, Rebecca M. Coulborn, Armand Sprecher, Anja De Weggheleire, Maria Mashako, Divya Nair, Justus Nsio Mbeta, and Emmanuel Lampaert
- Subjects
Viral Haemorrhagic Fever ,Central Africa ,SORT IT ,Outbreak ,Epidemic response ,Decentralized care ,eng ,Medicine ,Science - Abstract
Background Traditionally in the Democratic Republic of the Congo (DRC), centralised Ebola treatment centres (ETCs) have been set exclusively for Ebola virus disease (EVD) case management during outbreaks. During the 2020 EVD outbreak in DRC’s Equateur Province, existing health centres were equipped as decentralised treatment centres (DTC) to improve access for patients with suspected EVD. Between ETCs and DTCs, we compared the time from symptom onset to admission and diagnosis among patients with suspected EVD. Methods This was a cohort study based on analysis of a line-list containing demographic and clinical information of patients with suspected EVD admitted to any EVD health facility during the outbreak. Results Of 2359 patients with suspected EVD, 363 (15%) were first admitted to a DTC. Of 1996 EVD-suspected patients initially admitted to an ETC, 72 (4%) were confirmed as EVD-positive. Of 363 EVD-suspected patients initially admitted to a DTC, 6 (2%) were confirmed and managed as EVD-positive in the DTC. Among all EVD-suspected patients, the median (interquartile range) duration between symptom onset and admission was 2 (1-4) days in a DTC compared to 4 (2-7) days in an ETC (p
- Published
- 2024
- Full Text
- View/download PDF
40. Metagenomic data from gutter water in the city of Pointe-Noire, Republic of Congo
- Author
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Bouziane Moumen, Céline Samba-Louaka, Victoire Aubierge Matondo Kimpamboudi, Anicet Magloire Boumba, Hervé Sabin Ngoma, and Ascel Samba-Louaka
- Subjects
Antibiotic-resistance genes ,Shotgun metagenomics ,Gutter water ,Central Africa ,Computer applications to medicine. Medical informatics ,R858-859.7 ,Science (General) ,Q1-390 - Abstract
After Amazonia, the Congo Basin represents the second-largest tropical rainforest area in the world. This basin harbours remarkable biodiversity, yet much of its microbiological diversity within its waters, soils, and populations remains largely unexplored and undiscovered. While many initiatives to characterize global biodiversity are being undertaken, few are conducted in Africa and none of them concern the Congo Basin specifically in urban areas. In this context, we assessed the microbial diversity present in gutter water in the city of Pointe-Noire, Congo. This town has interesting characteristics as the population density is high and it is located between the Atlantic Ocean and the forest of Mayombe in Central Africa. The findings illuminate the microbial composition of surface water in Pointe-Noire. The dataset allows the identification of putative new bacteria through the assembly of 81 meta-genome-assembled genomes. It also serves as a valuable primary resource for assessing the presence of antibiotic-resistant genes, offering a useful tool for monitoring risks by public health authorities.
- Published
- 2024
- Full Text
- View/download PDF
41. HIV diagnosis in Equatorial Guinea. Keys to reduce the diagnostic and therapeutic delay
- Author
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Ana Rodríguez-Galet, Judit Ventosa-Cubillo, Verónica Bendomo, Manuel Eyene, Teresa Mikue-Owono, Jesús Nzang, Policarpo Ncogo, Agustín Benito, and África Holguín
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Rapid diagnostic tests ,False Diagnosis ,Therapeutic Failure ,Early Diagnosis ,Dried blood spots ,Central Africa ,Infectious and parasitic diseases ,RC109-216 ,Public aspects of medicine ,RA1-1270 - Abstract
Background: In Equatorial Guinea, only 54 % of people living with HIV know their HIV status. There are no confirmatory or molecular diagnostic techniques for early diagnosis or monitoring of infection in the country. Rapid diagnostic tests can induce false-positive diagnoses if used as a confirmatory technique. Our study aimed to identify the challenges of early HIV diagnosis in Equatorial Guinea by analyzing the rate of false positive diagnoses, diagnostic and therapeutic delays, and treatment failures among those on antiretroviral therapy. Methods: From 2019–2022, dried blood from 341 children, adolescents and adults diagnosed in Equatorial Guinea as HIV-positive by rapid diagnostic testing, and from 54 HIV-exposed infants were collected in Bata and sent to Madrid to confirm HIV-infection by molecular (Xpert HIV-1Qual, Cepheid) and/or serological confirmatory assays (Geenius-HIV-1/2, BioRad). HIV diagnostic delay (CD4 1,000RNA-HIV-1-copies/ml) were also studied after viral quantification (XpertVL HIV-1, Cepheid). Results: False-positive diagnoses were identified in 5 % of analysed samples. HIV infection was confirmed in 90.5 % of previously diagnosed patients in Equatorial Guinea and 3.7 % of HIV-exposed children undiagnosed in the field. Two-thirds of each new HIV patient had delayed diagnosis, and one-third had advanced disease. Treatment delay occurred in 28.3 % of patients, being around four times more likely in adolescents/adults than children. More than half (56 %) of 232 treated patients presented treatment failure, being significantly higher in children/adolescents than in adults (82.9 %/90 % vs. 45.6 %, p
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- 2024
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42. Environmental variation predicts patterns of genomic variation in an African tropical forest frog
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Courtney A. Miller, Geraud C. Tasse Taboue, Eric B. Fokam, Katy Morgan, Ying Zhen, Ryan J. Harrigan, Vinh Le Underwood, Kristen Ruegg, Paul R. Sesink Clee, Stephan Ntie, Patrick Mickala, Jean Francois Mboumba, Trevon Fuller, Breda M. Zimkus, Thomas B. Smith, and Nicola M. Anthony
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Central Africa ,amphibians ,RAD-seq ,environmental gradients ,genomic vulnerability ,climate change ,General. Including nature conservation, geographical distribution ,QH1-199.5 - Abstract
Central African rainforests are predicted to be disproportionately affected by future climate change. How species will cope with these changes is unclear, but rapid environmental changes will likely impose strong selection pressures. Here we examined environmental drivers of genomic variation in the central African puddle frog (Phrynobatrachus auritus) to identify areas of elevated environmentally-associated turnover. We also compared current and future climate models to pinpoint areas of high genomic vulnerability where allele frequencies will have to shift the most in order to keep pace with future climate change. Neither physical landscape barriers nor the effects of past Pleistocene refugia influenced genomic differentiation. Alternatively, geographic distance and seasonal aspects of precipitation are the most important drivers of SNP allele frequency variation. Patterns of genomic differentiation coincided with key ecological gradients across the forest-savanna ecotone, montane areas, and a coastal to interior rainfall gradient. Areas of greatest vulnerability were found in the lower Sanaga basin, the southeastern region of Cameroon, and southwest Gabon. In contrast with past conservation efforts that have focused on hotspots of species richness or endemism, our findings highlight the importance of maintaining environmentally heterogeneous landscapes to preserve genomic variation and ongoing evolutionary processes in the face of climate change.
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- 2024
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43. Availability of the current and future water resources in Central Africa, case of the large Sanaga catchment in Cameroon
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Valentin Brice Ebodé, Jean Guy Dzana, Raphael Onguéné, Sakaros Bogning Dongué, Bérenger Koffi, Jean Riotte, Gil Mahé, and Jean Jacques Braun
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Central Africa ,Sanaga River basin ,SWAT ,Regional climate models ,Climate variability ,Land use and land cover changes ,Physical geography ,GB3-5030 ,Geology ,QE1-996.5 - Abstract
Study region: Mbakaou and Bamendjing basins (Sanaga River sub-basins). Study focus: In this study, the availability of water resources was assessed over the period 2002–2019, based on the SWAT (Soil and Water Assessment Tool) hydrological model and certain meteorological and spatial reference data available for the region (Merra2, Landsat, etc.). Forecasts of its evolution were then made with the same tool (SWAT) over two futures periods (near 2024–2035 and medium: 2036–205) based on data from four (04) regional climate models (RCMs) (CCCma, HIRHAM5, RCA4 and REMO) and future land use and land cover (LULC) data simulated using the CA-Markov procedure. To separate the impact of climate variability (CV) and land use and use and land cover changes (LULCCs) on future water resources, two evolution scenarios (experiments) were established: (1) the impact of the CV, by associating future climate data with LULC from the historical period; (2) the impact of LULCCs, by combining future LULC maps with climate data from the historical period. New hydrological insights for the region: The performances of the SWAT model are satisfactory in calibration and validation on the two basins with R2, NSE and KGE greater than 0.68. Two models (CCCma and REMO) predict a decline in water resources in these basins, and two others (HIRHAM5 and RCA4) the opposite. The REMO model seems the most reliable. It predicts a drop in precipitation and runoff (SURQ) in the two basins that do not respectively exceed –19% and –31%. CV is the only forcing whose impact will be visible in the dynamics of future water resources, given the insignificant changes expected in the evolution of LULC patterns. The results of this study could contribute to improving the management of water resources in the studied basins and the region.
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- 2024
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44. Hydrocarbon accumulation history in Lower Cretaceous in northern slope of Bongor Basin in Chad, Central Africa
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Li WANG, Zhiquan NIE, Yebo DU, Lin WANG, Fanchao MENG, Yuliu CHEN, Jie HU, and Ruxin DING
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Central Africa ,Chad ,Bongor Basin ,Lower Cretaceous ,hydrocarbon accumulation stages ,fluid inclusions ,Petroleum refining. Petroleum products ,TP690-692.5 - Abstract
Based on the analysis of the fluid inclusion homogenization temperature and apatite fission track on the northern slope zone of the Bongor Basin in Chad, this paper studied the time and stages of hydrocarbon accumulation in the study area. The results show that: (1) The brine inclusions of the samples from the Kubla and Prosopis formations in the Lower Cretaceous coexisting with the hydrocarbon generally present two sets of peak ranges of homogenization temperature, with the peak ranges of low temperature and high temperature being 75–105 °C and 115–135 °C, respectively; (2) The samples from the Kubla and Prosopis formations have experienced five tectonic evolution stages, i.e., rapid subsidence in the Early Cretaceous, tectonic inversion in the Late Cretaceous, small subsidence in the Paleogene, uplift at the turn of the Paleogene and Neogene, and subsidence since the Miocene, in which the denudation thickness of the Late Cretaceous and after the turn of the Paleogene and Neogene are ~1.8 km and ~0.5 km, respectively. The cumulative denudation thickness of the two periods is about 2.3 km; (3) Using the brine inclusion homogenization temperature coexisting with the hydrocarbon as the capture temperature of the hydrocarbon, and combining with the apatite fission track thermal history modeling, the result shows that the Kubla and Prosopis formations in the Lower Cretaceous on the northern slope of the Bongor Basin have the same hydrocarbon accumulation time and stages, both of which have undergone two stages of hydrocarbon charging at 80–95 Ma and 65–80 Ma. The first stage of charging corresponds to the initial migration of hydrocarbon at the end of the Early Cretaceous rapid sedimentation, while the second stage of charging is in the stage of intense tectonic inversion in the Late Cretaceous.
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- 2024
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45. Genomic insights into Plasmodium vivax population structure and diversity in central Africa
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Valerie Gartner, Benjamin D. Redelings, Claudia Gaither, Jonathan B. Parr, Albert Kalonji, Fernandine Phanzu, Nicholas F. Brazeau, Jonathan J. Juliano, and Gregory A. Wray
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Malaria ,Plasmodium vivax ,Genome ,Duffy negative ,Sub-Saharan Africa ,Central Africa ,Arctic medicine. Tropical medicine ,RC955-962 ,Infectious and parasitic diseases ,RC109-216 - Abstract
Abstract Background Though Plasmodium vivax is the second most common malaria species to infect humans, it has not traditionally been considered a major human health concern in central Africa given the high prevalence of the human Duffy-negative phenotype that is believed to prevent infection. Increasing reports of asymptomatic and symptomatic infections in Duffy-negative individuals throughout Africa raise the possibility that P. vivax is evolving to evade host resistance, but there are few parasite samples with genomic data available from this part of the world. Methods Whole genome sequencing of one new P. vivax isolate from the Democratic Republic of the Congo (DRC) was performed and used in population genomics analyses to assess how this central African isolate fits into the global context of this species. Results Plasmodium vivax from DRC is similar to other African populations and is not closely related to the non-human primate parasite P. vivax-like. Evidence is found for a duplication of the gene PvDBP and a single copy of PvDBP2. Conclusion These results suggest an endemic P. vivax population is present in central Africa. Intentional sampling of P. vivax across Africa would further contextualize this sample within African P. vivax diversity and shed light on the mechanisms of infection in Duffy negative individuals. These results are limited by the uncertainty of how representative this single sample is of the larger population of P. vivax in central Africa.
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- 2024
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46. Engaging with Afghanistan will get harder for West
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- 2024
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47. Projected changes in population exposure to extreme precipitation events over Central Africa under the global warming levels of 1.5 °C and 2 °C: insights from CMIP6 simulations
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Ngavom, Zakariahou, Fotso-Nguemo, Thierry C., Vondou, Derbetini A., Fotso-Kamga, Gabriel, Zebaze, Sinclaire, Yepdo, Zéphirin D., and Diedhiou, Arona
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- 2024
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48. Hydrocarbon accumulation history in Lower Cretaceous in northern slope of Bongor Basin in Chad, Central Africa.
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WANG Li, NIE Zhiquan, DU Yebo, WANG Lin, MENG Fanchao, CHEN Yuliu, HU Jie, and DING Ruxin
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HYDROCARBON reservoirs ,APATITE ,CHEMICAL denudation ,FLUID inclusions - Abstract
Based on the analysis of the fluid inclusion homogenization temperature and apatite fission track on the northern slope zone of the Bongor Basin in Chad, this paper studied the time and stages of hydrocarbon accumulation in the study area. The results show that: (1) The brine inclusions of the samples from the Kubla and Prosopis formations in the Lower Cretaceous coexisting with the hydrocarbon generally present two sets of peak ranges of homogenization temperature, with the peak ranges of low temperature and high temperature being 75-105 C and 115-135 C, respectively; (2) The samples from the Kubla and Prosopis formations have experienced five tectonic evolution stages, i.e., rapid subsidence in the Early Cretaceous, tectonic inversion in the Late Cretaceous, small subsidence in the Paleogene, uplift at the turn of the Paleogene and Neogene, and subsidence since the Miocene, in which the denudation thickness of the Late Cretaceous and after the turn of the Paleogene and Neogene are ~1.8 km and ~0.5 km, respectively. The cumulative denudation thickness of the two periods is about 2.3 km; (3) Using the brine inclusion homogenization temperature coexisting with the hydrocarbon as the capture temperature of the hydrocarbon, and combining with the apatite fission track thermal history modeling, the result shows that the Kubla and Prosopis formations in the Lower Cretaceous on the northern slope of the Bongor Basin have the same hydrocarbon accumulation time and stages, both of which have undergone two stages of hydrocarbon charging at 80-95 Ma and 65-80 Ma. The first stage of charging corresponds to the initial migration of hydrocarbon at the end of the Early Cretaceous rapid sedimentation, while the second stage of charging is in the stage of intense tectonic inversion in the Late Cretaceous. [ABSTRACT FROM AUTHOR]
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- 2024
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49. How to wield regional power from afar: a conceptual discussion illustrated by the case of France in Central Africa.
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Mattheis, Frank
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What does it take to belong to a region and exert power over it? The scholarship on regional powers has elaborated sophisticated indicators to establish nuances of power, but the depiction of the region has remained vague. Most approaches are characterised by a narrow territorial interpretation that does not properly take into account power wielded by geographically distant actors. Using the case of France in Central Africa this article argues that a distant state can a) hold a dominant share of military, economic and soft power, b) use this power for hegemonic behaviour and c) be recognised as a leader in the region by both internal and external actors. The main specificity of distant actors as regional powers is the greater necessity for a legitimising narrative. France tackles this hurdle with the help of regional organisations that reproduce imperial structures. By holding the informal status of a quasi-member in regional governance structures, France participates in region-building processes from the inside rather than the outside. [ABSTRACT FROM AUTHOR]
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- 2024
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50. Genomic insights into Plasmodium vivax population structure and diversity in central Africa.
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Gartner, Valerie, Redelings, Benjamin D., Gaither, Claudia, Parr, Jonathan B., Kalonji, Albert, Phanzu, Fernandine, Brazeau, Nicholas F., Juliano, Jonathan J., and Wray, Gregory A.
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PLASMODIUM vivax , *TRYPANOSOMA , *WHOLE genome sequencing , *DISEASE resistance of plants , *CHROMOSOME duplication , *HUMAN phenotype - Abstract
Background: Though Plasmodium vivax is the second most common malaria species to infect humans, it has not traditionally been considered a major human health concern in central Africa given the high prevalence of the human Duffy-negative phenotype that is believed to prevent infection. Increasing reports of asymptomatic and symptomatic infections in Duffy-negative individuals throughout Africa raise the possibility that P. vivax is evolving to evade host resistance, but there are few parasite samples with genomic data available from this part of the world. Methods: Whole genome sequencing of one new P. vivax isolate from the Democratic Republic of the Congo (DRC) was performed and used in population genomics analyses to assess how this central African isolate fits into the global context of this species. Results: Plasmodium vivax from DRC is similar to other African populations and is not closely related to the non-human primate parasite P. vivax-like. Evidence is found for a duplication of the gene PvDBP and a single copy of PvDBP2. Conclusion: These results suggest an endemic P. vivax population is present in central Africa. Intentional sampling of P. vivax across Africa would further contextualize this sample within African P. vivax diversity and shed light on the mechanisms of infection in Duffy negative individuals. These results are limited by the uncertainty of how representative this single sample is of the larger population of P. vivax in central Africa. [ABSTRACT FROM AUTHOR]
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- 2024
- Full Text
- View/download PDF
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