WorldWideScience

Sample records for east african savanna

  1. Spatial vegetation patterns and neighborhood competition among woody plants in an East African savanna.

    Science.gov (United States)

    Dohn, Justin; Augustine, David J; Hanan, Niall P; Ratnam, Jayashree; Sankaran, Mahesh

    2017-02-01

    The majority of research on savanna vegetation dynamics has focused on the coexistence of woody and herbaceous vegetation. Interactions among woody plants in savannas are relatively poorly understood. We present data from a 10-yr longitudinal study of spatially explicit growth patterns of woody vegetation in an East African savanna following exclusion of large herbivores and in the absence of fire. We examined plant spatial patterns and quantified the degree of competition among woody individuals. Woody plants in this semiarid savanna exhibit strongly clumped spatial distributions at scales of 1-5 m. However, analysis of woody plant growth rates relative to their conspecific and heterospecific neighbors revealed evidence for strong competitive interactions at neighborhood scales of up to 5 m for most woody plant species. Thus, woody plants were aggregated in clumps despite significantly decreased growth rates in close proximity to neighbors, indicating that the spatial distribution of woody plants in this region depends on dispersal and establishment processes rather than on competitive, density-dependent mortality. However, our documentation of suppressive effects of woody plants on neighbors also suggests a potentially important role for tree-tree competition in controlling vegetation structure and indicates that the balanced-competition hypothesis may contribute to well-known patterns in maximum tree cover across rainfall gradients in Africa. © 2016 by the Ecological Society of America.

  2. Fire and life in Tarangire : effects of burning and herbivory on an East African Savanna system

    NARCIS (Netherlands)

    Vijver, van de C.A.D.M.

    1999-01-01

    This thesis investigates the effects of fire on quality and quantity of forage for grazers in the savannas of East Africa where fire has been used as a tool in pasture management for centuries. Hereby the mechanisms that cause the effects, as well as the manner in which the effects are

  3. Termites create spatial structure and govern ecosystem function by affecting N2 fixation in an East African savanna.

    Science.gov (United States)

    Fox-Dobbs, Kena; Doak, Daniel F; Brody, Alison K; Palmer, Todd M

    2010-05-01

    The mechanisms by which even the clearest of keystone or dominant species exert community-wide effects are only partially understood in most ecosystems. This is especially true when a species or guild influences community-wide interactions via changes in the abiotic landscape. Using stable isotope analyses, we show that subterranean termites in an East African savanna strongly influence a key ecosystem process: atmospheric nitrogen fixation by a monodominant tree species and its bacterial symbionts. Specifically, we applied the 15N natural abundance method in combination with other biogeochemical analyses to assess levels of nitrogen fixation by Acacia drepanolobium and its effects on co-occurring grasses and forbs in areas near and far from mounds and where ungulates were or were not excluded. We find that termites exert far stronger effects than do herbivores on nitrogen fixation. The percentage of nitrogen derived from fixation in Acacia drepanolobium trees is higher (55-80%) away from mounds vs. near mounds (40-50%). Mound soils have higher levels of plant available nitrogen, and Acacia drepanolobium may preferentially utilize soil-based nitrogen sources in lieu of fixed nitrogen when these sources are readily available near termite mounds. At the scale of the landscape, our models predict that termite/soil derived nitrogen sources influence >50% of the Acacia drepanolobium trees in our system. Further, the spatial extent of these effects combine with the spacing of termite mounds to create highly regular patterning in nitrogen fixation rates, resulting in marked habitat heterogeneity in an otherwise uniform landscape. In summary, we show that termite-associated effects on nitrogen processes are not only stronger than those of more apparent large herbivores in the same system, but also occur in a highly regular spatial pattern, potentially adding to their importance as drivers of community and ecosystem structure.

  4. Biomass burning in West African savannas

    International Nuclear Information System (INIS)

    Menaut, J.C.; Abbadie, L.; Lavenu, F.; Loudjani, P.; Podaire, A.

    1991-01-01

    This chapter approaches the influence of West African savanna ecosystems on the regional climate by giving, as precisely as possible, the amount of volatilized elements (e.g., carbon, nitrogen, and sulfur) annually released by bush fires into the atmosphere. In spite of the relative functional similarity of West African savannas, fire behavior and effects vary with the different bioclimatic and phytogeographic zones of the region: Guinea or humid zone; Sudan or mesic zone; and, Sahel or arid zone. In order to reach an acceptable accuracy, results are given for each of the zones described and summarized for West Africa

  5. Tree-grass interactions on an East African savanna : the effects of facilitation, competition, and hydraulic lift

    NARCIS (Netherlands)

    Ludwig, F.

    2001-01-01

    Keywords: Rangelands, Semi-arid areas, stable isotopes, Acacia, C 4- grasses, plant nutrients, soil nutrients, soil water, plant water relations

    Savanna trees can either increase or decrease the productivity of understorey grasses. Trees reduce grass

  6. Determinants of woody cover in African savannas

    Science.gov (United States)

    Sankaran, M.; Hanan, N.P.; Scholes, Robert J.; Ratnam, J.; Augustine, D.J.; Cade, B.S.; Gignoux, J.; Higgins, S.I.; Le, Roux X.; Ludwig, F.; Ardo, J.; Banyikwa, F.; Bronn, A.; Bucini, G.; Caylor, K.K.; Coughenour, M.B.; Diouf, A.; Ekaya, W.; Feral, C.J.; February, E.C.; Frost, P.G.H.; Hiernaux, P.; Hrabar, H.; Metzger, K.L.; Prins, H.H.T.; Ringrose, S.; Sea, W.; Tews, J.; Worden, J.; Zambatis, N.

    2005-01-01

    Savannas are globally important ecosystems of great significance to human economies. In these biomes, which are characterized by the co-dominance of trees and grasses, woody cover is a chief determinant of ecosystem properties 1-3. The availability of resources (water, nutrients) and disturbance regimes (fire, herbivory) are thought to be important in regulating woody cover1,2,4,5, but perceptions differ on which of these are the primary drivers of savanna structure. Here we show, using data from 854 sites across Africa, that maximum woody cover in savannas receiving a mean annual precipitation (MAP) of less than ???650 mm is constrained by, and increases linearly with, MAP. These arid and semi-arid savannas may be considered 'stable' systems in which water constrains woody cover and permits grasses to coexist, while fire, herbivory and soil properties interact to reduce woody cover below the MAP-controlled upper bound. Above a MAP of ???650 mm, savannas are 'unstable' systems in which MAP is sufficient for woody canopy closure, and disturbances (fire, herbivory) are required for the coexistence of trees and grass. These results provide insights into the nature of African savannas and suggest that future changes in precipitation 6 may considerably affect their distribution and dynamics. ?? 2005 Nature Publishing Group.

  7. Unsustainable fuelwood extraction from South African savannas

    Science.gov (United States)

    Wessels, K. J.; Colgan, M. S.; Erasmus, B. F. N.; Asner, G. P.; Twine, W. C.; Mathieu, R.; van Aardt, J. A. N.; Fisher, J. T.; Smit, I. P. J.

    2013-03-01

    Wood and charcoal supply the majority of sub-Saharan Africa’s rural energy needs. The long-term supply of fuelwood is in jeopardy given high consumption rates. Using airborne light detection and ranging (LiDAR), we mapped and investigated savanna aboveground biomass across contrasting land uses, ranging from densely populated communal areas to highly protected areas in the Lowveld savannas of South Africa. We combined the LiDAR observations with socio-economic data, biomass production rates and fuelwood consumption rates in a supply-demand model to predict future fuelwood availability. LiDAR-based biomass maps revealed disturbance gradients around settlements up to 1.5 km, corresponding to the maximum distance walked to collect fuelwood. At current levels of fuelwood consumption (67% of households use fuelwood exclusively, with a 2% annual reduction), we calculate that biomass in the study area will be exhausted within thirteen years. We also show that it will require a 15% annual reduction in consumption for eight years to a level of 20% of households using fuelwood before the reduction in biomass appears to stabilize to sustainable levels. The severity of dwindling fuelwood reserves in African savannas underscores the importance of providing affordable energy for rural economic development.

  8. Unsustainable fuelwood extraction from South African savannas

    International Nuclear Information System (INIS)

    Wessels, K J; Colgan, M S; Asner, G P; Erasmus, B F N; Twine, W C; Fisher, J T; Mathieu, R; Van Aardt, J A N; Smit, I P J

    2013-01-01

    Wood and charcoal supply the majority of sub-Saharan Africa’s rural energy needs. The long-term supply of fuelwood is in jeopardy given high consumption rates. Using airborne light detection and ranging (LiDAR), we mapped and investigated savanna aboveground biomass across contrasting land uses, ranging from densely populated communal areas to highly protected areas in the Lowveld savannas of South Africa. We combined the LiDAR observations with socio-economic data, biomass production rates and fuelwood consumption rates in a supply–demand model to predict future fuelwood availability. LiDAR-based biomass maps revealed disturbance gradients around settlements up to 1.5 km, corresponding to the maximum distance walked to collect fuelwood. At current levels of fuelwood consumption (67% of households use fuelwood exclusively, with a 2% annual reduction), we calculate that biomass in the study area will be exhausted within thirteen years. We also show that it will require a 15% annual reduction in consumption for eight years to a level of 20% of households using fuelwood before the reduction in biomass appears to stabilize to sustainable levels. The severity of dwindling fuelwood reserves in African savannas underscores the importance of providing affordable energy for rural economic development. (letter)

  9. Can savannas help balance the South African greenhouse gas budget?

    CSIR Research Space (South Africa)

    Scholes, RJ

    1996-02-01

    Full Text Available This article discusses the South African Greenhouse Experiment on Savannas (SAGES) study conducted by the CSIR' Division of Forest Science and Technology (Foretek) on the role of savannas in the balance of the greenhouse gas budget of South Africa...

  10. East African Cenozoic vegetation history.

    Science.gov (United States)

    Linder, Hans Peter

    2017-11-01

    The modern vegetation of East Africa is a complex mosaic of rainforest patches; small islands of tropic-alpine vegetation; extensive savannas, ranging from almost pure grassland to wooded savannas; thickets; and montane grassland and forest. Here I trace the evolution of these vegetation types through the Cenozoic. Paleogene East Africa was most likely geomorphologically subdued and, as the few Eocene fossil sites suggest, a woodland in a seasonal climate. Woodland rather than rainforest may well have been the regional vegetation. Mountain building started with the Oligocene trap lava flows in Ethiopia, on which rainforest developed, with little evidence of grass and none of montane forests. The uplift of the East African Plateau took place during the middle Miocene. Fossil sites indicate the presence of rainforest, montane forest and thicket, and wooded grassland, often in close juxtaposition, from 17 to 10 Ma. By 10 Ma, marine deposits indicate extensive grassland in the region and isotope analysis indicates that this was a C 3 grassland. In the later Miocene rifting, first of the western Albertine Rift and then of the eastern Gregory Rift, added to the complexity of the environment. The building of the high strato-volcanos during the later Mio-Pliocene added environments suitable for tropic-alpine vegetation. During this time, the C 3 grassland was replaced by C 4 savannas, although overall the extent of grassland was reduced from the mid-Miocene high to the current low level. Lake-level fluctuations during the Quaternary indicate substantial variation in rainfall, presumably as a result of movements in the intertropical convergence zone and the Congo air boundary, but the impact of these fluctuations on the vegetation is still speculative. I argue that, overall, there was an increase in the complexity of East African vegetation complexity during the Neogene, largely as a result of orogeny. The impact of Quaternary climatic fluctuation is still poorly understood

  11. A continental analysis of correlations between tree patterns in African savannas and human and environmental variables

    NARCIS (Netherlands)

    Groen, T.A.; Langevelde, van F.; Vijver, van de C.A.D.M.; Raad, de A.L.; Leeuw, de J.; Prins, H.H.T.

    2011-01-01

    This study analyses possible relationships between natural processes taking place in savannas and the tree patterns found in savannas. This can lead to new hypotheses about which processes are driving savanna physiognomy. To do so tree patterns were quantified for African savannas from historical

  12. East African Medical Journal

    African Journals Online (AJOL)

    The East African Medical Journal is intended for publication of papers on ... research on problems relevant to East Africa and other African countries will receive special ... Analysis of survival patterns of TB‐HIV co‐infected patients in relation to ...

  13. Determinants of woody cover in African savannas

    CSIR Research Space (South Africa)

    Sankaran, M

    2005-12-08

    Full Text Available workshop on savanna complexity funded by the NSF. We thank R. Boone, I. McHugh, R. Grant, H. Biggs, W. T. Starmer, P. M. Barbosa, D. Ruess, J. Rettenmayer, C. Williams, J. Klein, M. T. Anderson, W. J. Parton, J. C. Neff, N. Govender and the Kruger Park...

  14. Savanna browse production. 2: Prediction | Penderis | African ...

    African Journals Online (AJOL)

    Our study was initiated with the aim of modelling browse production rates of key savanna tree species in the northern Zululand region of KwaZulu-Natal, with the assumption that browse production equates to utilised browse biomass. Predictive models for the production of browse, at different game feeding levels, ...

  15. EAST AFRICAN MEDICAL JOURNAL

    African Journals Online (AJOL)

    2003-11-11

    Nov 11, 2003 ... East African Medical Journal Vol. ... Lecturer/Consultant Surgeon, Paediatric Surgery Unit, Department of Surgery, College of Medical Sciences, University of Calabar, .... mind and the results obtained were however satisfying.

  16. Light hydrocarbon emissions from African savanna burnings

    International Nuclear Information System (INIS)

    Bonsang, B.; Lambert, G.; Boissard, C.C.

    1991-01-01

    A study was undertaken in West Africa to determine the background mixing ratio of nonmethane hydrocarbons (NMHC) during the dry season and to measure the composition of savanna burnings. The experiment was conducted from 13 to 22 January 1989 in the experimental station located at the border of the tropical rainforest and savanna. Samples were collected during aircraft flights at 2,400 m in the free troposphere, at 400 m in the haze layer and in a smoke plume at 200 m altitude. Samples representing the ground-level evolution of the local background were collected at 10 m altitude. Fire samples were collected at a short distance from the fires during the intensive experiments. Results are presented in tables and indicate that the effect of NMHC produced by biomass burning on the tropospheric photochemistry is limited to a few species, namely, C 2 -C 4 alkenes

  17. African savanna-forest boundary dynamics

    DEFF Research Database (Denmark)

    Cuni Sanchez, Aida; White, Lee J. T.; Calders, Kim

    2016-01-01

    -term inventory plots we quantify changes in vegetation structure, above-ground biomass (AGB) and biodiversity of trees ≥10 cm diameter over 20 years for five vegetation types: savanna; colonising forest (F1), monodominant Okoume forest (F2); young Marantaceae forest (F3); and mixed Marantaceae forest (F4...... substantially in structure, AGB or diversity. Critically, the stability of the F3 stage implies that this stage may be maintained for long periods. Soil carbon was low, and did not show a successional gradient as for AGB and diversity. TLS vertical plant profiles showed distinctive differences amongst...... the vegetation types, indicating that this technique can improve ecological understanding. We highlight two points: (i) as forest colonises, changes in biodiversity are much slower than changes in forest structure or AGB; and (ii) all forest types store substantial quantities of carbon. Multidecadal monitoring...

  18. Unsustainable fuelwood extraction from South African savannas

    CSIR Research Space (South Africa)

    Wessels, Konrad J

    2013-01-01

    Full Text Available Department of Global Ecology, Carnegie Institution for Science, 260 Panama Street, Stanford, CA 94305, USA 4 Centre for African Ecology, School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Private Bag 3, Johannesburg, Wits... Supplies in the Developing Countries (Forestry Paper No. 42) (Rome: Food and Agriculture Organisation) Dewees P A 1989 The woodfuel crisis reconsidered: observations on the dynamics of abundance and scarcity World Dev. 17 1159–72 Dovie D B K, Shackleton C M...

  19. Taxonomy Icon Data: African savanna elephant [Taxonomy Icon

    Lifescience Database Archive (English)

    Full Text Available African savanna elephant Loxodonta africana Chordata/Vertebrata/Mammalia/Theria/Eutheria/etc. Loxodonta_afri...cana_L.png Loxodonta_africana_NL.png Loxodonta_africana_S.png Loxodonta_africana_NS....png http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Loxodonta+africana&t=L http://biosciencedbc.jp/taxonom...y_icon/icon.cgi?i=Loxodonta+africana&t=NL http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Loxodonta+afric...ana&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Loxodonta+africana&t=NS ...

  20. Patterns in woody vegetation structure across African savannas

    Science.gov (United States)

    Axelsson, Christoffer R.; Hanan, Niall P.

    2017-07-01

    Vegetation structure in water-limited systems is to a large degree controlled by ecohydrological processes, including mean annual precipitation (MAP) modulated by the characteristics of precipitation and geomorphology that collectively determine how rainfall is distributed vertically into soils or horizontally in the landscape. We anticipate that woody canopy cover, crown density, crown size, and the level of spatial aggregation among woody plants in the landscape will vary across environmental gradients. A high level of woody plant aggregation is most distinct in periodic vegetation patterns (PVPs), which emerge as a result of ecohydrological processes such as runoff generation and increased infiltration close to plants. Similar, albeit weaker, forces may influence the spatial distribution of woody plants elsewhere in savannas. Exploring these trends can extend our knowledge of how semi-arid vegetation structure is constrained by rainfall regime, soil type, topography, and disturbance processes such as fire. Using high-spatial-resolution imagery, a flexible classification framework, and a crown delineation method, we extracted woody vegetation properties from 876 sites spread over African savannas. At each site, we estimated woody cover, mean crown size, crown density, and the degree of aggregation among woody plants. This enabled us to elucidate the effects of rainfall regimes (MAP and seasonality), soil texture, slope, and fire frequency on woody vegetation properties. We found that previously documented increases in woody cover with rainfall is more consistently a result of increasing crown size than increasing density of woody plants. Along a gradient of mean annual precipitation from the driest (< 200 mm yr-1) to the wettest (1200-1400 mm yr-1) end, mean estimates of crown size, crown density, and woody cover increased by 233, 73, and 491 % respectively. We also found a unimodal relationship between mean crown size and sand content suggesting that maximal

  1. Patterns in woody vegetation structure across African savannas

    Directory of Open Access Journals (Sweden)

    C. R. Axelsson

    2017-07-01

    Full Text Available Vegetation structure in water-limited systems is to a large degree controlled by ecohydrological processes, including mean annual precipitation (MAP modulated by the characteristics of precipitation and geomorphology that collectively determine how rainfall is distributed vertically into soils or horizontally in the landscape. We anticipate that woody canopy cover, crown density, crown size, and the level of spatial aggregation among woody plants in the landscape will vary across environmental gradients. A high level of woody plant aggregation is most distinct in periodic vegetation patterns (PVPs, which emerge as a result of ecohydrological processes such as runoff generation and increased infiltration close to plants. Similar, albeit weaker, forces may influence the spatial distribution of woody plants elsewhere in savannas. Exploring these trends can extend our knowledge of how semi-arid vegetation structure is constrained by rainfall regime, soil type, topography, and disturbance processes such as fire. Using high-spatial-resolution imagery, a flexible classification framework, and a crown delineation method, we extracted woody vegetation properties from 876 sites spread over African savannas. At each site, we estimated woody cover, mean crown size, crown density, and the degree of aggregation among woody plants. This enabled us to elucidate the effects of rainfall regimes (MAP and seasonality, soil texture, slope, and fire frequency on woody vegetation properties. We found that previously documented increases in woody cover with rainfall is more consistently a result of increasing crown size than increasing density of woody plants. Along a gradient of mean annual precipitation from the driest (< 200 mm yr−1 to the wettest (1200–1400 mm yr−1 end, mean estimates of crown size, crown density, and woody cover increased by 233, 73, and 491 % respectively. We also found a unimodal relationship between mean crown size and sand

  2. Human impacts in African savannas are mediated by plant functional traits.

    Science.gov (United States)

    Osborne, Colin P; Charles-Dominique, Tristan; Stevens, Nicola; Bond, William J; Midgley, Guy; Lehmann, Caroline E R

    2018-05-28

    Tropical savannas have a ground cover dominated by C 4 grasses, with fire and herbivory constraining woody cover below a rainfall-based potential. The savanna biome covers 50% of the African continent, encompassing diverse ecosystems that include densely wooded Miombo woodlands and Serengeti grasslands with scattered trees. African savannas provide water, grazing and browsing, food and fuel for tens of millions of people, and have a unique biodiversity that supports wildlife tourism. However, human impacts are causing widespread and accelerating degradation of savannas. The primary threats are land cover-change and transformation, landscape fragmentation that disrupts herbivore communities and fire regimes, climate change and rising atmospheric CO 2 . The interactions among these threats are poorly understood, with unknown consequences for ecosystem health and human livelihoods. We argue that the unique combinations of plant functional traits characterizing the major floristic assemblages of African savannas make them differentially susceptible and resilient to anthropogenic drivers of ecosystem change. Research must address how this functional diversity among African savannas differentially influences their vulnerability to global change and elucidate the mechanisms responsible. This knowledge will permit appropriate management strategies to be developed to maintain ecosystem integrity, biodiversity and livelihoods. © 2018 The Authors New Phytologist © 2018 New Phytologist Trust.

  3. Spatial pattern enhances ecosystem functioning in an African savanna.

    Science.gov (United States)

    Pringle, Robert M; Doak, Daniel F; Brody, Alison K; Jocqué, Rudy; Palmer, Todd M

    2010-05-25

    The finding that regular spatial patterns can emerge in nature from local interactions between organisms has prompted a search for the ecological importance of these patterns. Theoretical models have predicted that patterning may have positive emergent effects on fundamental ecosystem functions, such as productivity. We provide empirical support for this prediction. In dryland ecosystems, termite mounds are often hotspots of plant growth (primary productivity). Using detailed observations and manipulative experiments in an African savanna, we show that these mounds are also local hotspots of animal abundance (secondary and tertiary productivity): insect abundance and biomass decreased with distance from the nearest termite mound, as did the abundance, biomass, and reproductive output of insect-eating predators. Null-model analyses indicated that at the landscape scale, the evenly spaced distribution of termite mounds produced dramatically greater abundance, biomass, and reproductive output of consumers across trophic levels than would be obtained in landscapes with randomly distributed mounds. These emergent properties of spatial pattern arose because the average distance from an arbitrarily chosen point to the nearest feature in a landscape is minimized in landscapes where the features are hyper-dispersed (i.e., uniformly spaced). This suggests that the linkage between patterning and ecosystem functioning will be common to systems spanning the range of human management intensities. The centrality of spatial pattern to system-wide biomass accumulation underscores the need to conserve pattern-generating organisms and mechanisms, and to incorporate landscape patterning in efforts to restore degraded habitats and maximize the delivery of ecosystem services.

  4. Spatial pattern enhances ecosystem functioning in an African savanna.

    Directory of Open Access Journals (Sweden)

    Robert M Pringle

    2010-05-01

    Full Text Available The finding that regular spatial patterns can emerge in nature from local interactions between organisms has prompted a search for the ecological importance of these patterns. Theoretical models have predicted that patterning may have positive emergent effects on fundamental ecosystem functions, such as productivity. We provide empirical support for this prediction. In dryland ecosystems, termite mounds are often hotspots of plant growth (primary productivity. Using detailed observations and manipulative experiments in an African savanna, we show that these mounds are also local hotspots of animal abundance (secondary and tertiary productivity: insect abundance and biomass decreased with distance from the nearest termite mound, as did the abundance, biomass, and reproductive output of insect-eating predators. Null-model analyses indicated that at the landscape scale, the evenly spaced distribution of termite mounds produced dramatically greater abundance, biomass, and reproductive output of consumers across trophic levels than would be obtained in landscapes with randomly distributed mounds. These emergent properties of spatial pattern arose because the average distance from an arbitrarily chosen point to the nearest feature in a landscape is minimized in landscapes where the features are hyper-dispersed (i.e., uniformly spaced. This suggests that the linkage between patterning and ecosystem functioning will be common to systems spanning the range of human management intensities. The centrality of spatial pattern to system-wide biomass accumulation underscores the need to conserve pattern-generating organisms and mechanisms, and to incorporate landscape patterning in efforts to restore degraded habitats and maximize the delivery of ecosystem services.

  5. Leaf green-up in a semi-arid African savanna - separating tree and grass responses to environmental cues

    CSIR Research Space (South Africa)

    Archibald, S

    2007-01-01

    Full Text Available -arid African savanna - 583 Journal of Vegetation Science 18: 583-594, 2007 © IAVS; Opulus Press Uppsala. Leaf green-up in a semi-arid African savanna – separating tree and grass responses to environmental cues Archibald, S.1* & Scholes, R.J.1,2 1Natural... to identify tree and grass green-up dates in a semi-arid savanna system, and are there predictable environmental cues for green-up for each life form? Location: Acacia nigrescens/Combretum apiculatum savanna, Kruger National Park, South Africa (25° S, 31...

  6. East African Journal of Statistics: Journal Sponsorship

    African Journals Online (AJOL)

    East African Journal of Statistics: Journal Sponsorship. Journal Home > About the Journal > East African Journal of Statistics: Journal Sponsorship. Log in or Register to get access to full text downloads.

  7. East African Orthopaedic Journal: Submissions

    African Journals Online (AJOL)

    Author Guidelines. The East African Orthopaedic Journal is published biannually by the Kenya Orthopaedics Association. Its primary objective is to give researchers in orthopaedics and ... Format should be as follows; Details of authors as for original articles, summary of not more than 200 words, introduction, case report,

  8. East African Medical Journal

    African Journals Online (AJOL)

    Paris, France, K. C. Takarinda, BSc, MSc, International Union Against Tuberculosis and Lung ... Kenya and T. Galgalo, MSc, African Field Epidemiology Network. ... times more likely to develop active TB than those ... isoniazid preventive therapy (IPT), intensified TB case ... The capital city, where this study took place, had a.

  9. Impact of goat browsing on Aloe ferox in a South African savanna ...

    African Journals Online (AJOL)

    The extent and impact of the utilisation of Aloe ferox by Boer goats during winter in a South African savanna was determined using a plant-based approach. All Aloe plants rooted within the transects were eaten by goats, with small plants utilised more frequently than tall plants. The density of dying and dead Aloe plants was ...

  10. Modelling annual evapotranspiration in a semi-arid, African savanna ...

    African Journals Online (AJOL)

    Accurately measuring evapotranspiration (ET) is essential if we are to derive reasonable estimates of production and water use for semi-arid savannas. Estimates of ET are also important in defining the health of an ecosystem and the quantity of water used by the vegetation when preparing a catchment-scale water balance.

  11. Facilitation between bovids and equids on an African savanna

    NARCIS (Netherlands)

    Odadi, W.O.; Jain, M.; Wieren, van S.E.; Prins, H.H.T.; Rubenstein, D.I.

    2011-01-01

    Background: Equids, especially zebras and donkeys, and cattle (bovids) share habitats in many savanna ecosystems in Africa. The issue of competition for food between these ungulate guilds remains largely unresolved. Resolving it will provide insights into how wild zebra are likely to interact with

  12. Analysis of farmers’ adaptation to weather extremes in West African Sudan Savanna

    Directory of Open Access Journals (Sweden)

    David Boansi

    2017-06-01

    Full Text Available There have been recent incidences of weather extremes in the West African Sudan Savanna and farmers have responded through implementation of relevant adaptation strategies. For a deeper insight into farmers’ adaptation to climatic shocks, this study documents farmers’ perception of recent changes in the local climate, and identifies factors that influence the number and choice of strategies implemented. Interdependencies among strategies are explored and joint and marginal probabilities of adoption estimated. Upper East Ghana and Southwest Burkina Faso are used as the case study regions. These regions were selected due to extreme reliance of inhabitants on agriculture for sustenance, and their recent exposure to weather extremes. Through estimation of a Poisson regression and multivariate probit model to identify the major factors that influence the number and choice of strategies adopted, we discover that, limited access to credit, markets, and extension services, smaller cropland area, and low level of mechanization could impede effective adaptation to weather extremes. To enhance farmers’ adaptive capacity, policy makers and various stakeholders need to contribute towards improving farmers’ access to credit, markets, and extension services, and implement measures to promote mechanization.

  13. African Savanna-Forest Boundary Dynamics: A 20-Year Study

    Science.gov (United States)

    Cuni-Sanchez, Aida; White, Lee J. T.; Calders, Kim; Jeffery, Kathryn J.; Abernethy, Katharine; Burt, Andrew; Disney, Mathias; Gilpin, Martin; Gomez-Dans, Jose L.; Lewis, Simon L.

    2016-01-01

    Recent studies show widespread encroachment of forest into savannas with important consequences for the global carbon cycle and land-atmosphere interactions. However, little research has focused on in situ measurements of the successional sequence of savanna to forest in Africa. Using long-term inventory plots we quantify changes in vegetation structure, above-ground biomass (AGB) and biodiversity of trees ≥10 cm diameter over 20 years for five vegetation types: savanna; colonising forest (F1), monodominant Okoume forest (F2); young Marantaceae forest (F3); and mixed Marantaceae forest (F4) in Lopé National Park, central Gabon, plus novel 3D terrestrial laser scanning (TLS) measurements to assess forest structure differences. Over 20 years no plot changed to a new stage in the putative succession, but F1 forests strongly moved towards the structure, AGB and diversity of F2 forests. Overall, savanna plots showed no detectable change in structure, AGB or diversity using this method, with zero trees ≥10 cm diameter in 1993 and 2013. F1 and F2 forests increased in AGB, mainly as a result of adding recruited stems (F1) and increased Basal Area (F2), whereas F3 and F4 forests did not change substantially in structure, AGB or diversity. Critically, the stability of the F3 stage implies that this stage may be maintained for long periods. Soil carbon was low, and did not show a successional gradient as for AGB and diversity. TLS vertical plant profiles showed distinctive differences amongst the vegetation types, indicating that this technique can improve ecological understanding. We highlight two points: (i) as forest colonises, changes in biodiversity are much slower than changes in forest structure or AGB; and (ii) all forest types store substantial quantities of carbon. Multi-decadal monitoring is likely to be required to assess the speed of transition between vegetation types. PMID:27336632

  14. Scopus: Journal of East African Ornithology

    African Journals Online (AJOL)

    Scopus: Journal of East African Ornithology has been published since 1977 by the Bird Committee of the East Africa Natural History Society. Originally titled Scopus, the addition of Journal of East African Ornithology began with our January 2018 issue. The journal is published Open Access twice a year, typically in January ...

  15. Western equatorial African forest-savanna mosaics: a legacy of late Holocene climatic change?

    Directory of Open Access Journals (Sweden)

    A. Ngomanda

    2009-10-01

    Full Text Available Past vegetation and climate changes reconstructed using two pollen records from Lakes Maridor and Nguène, located in the coastal savannas and inland rainforest of Gabon, respectively, provide new insights into the environmental history of western equatorial African rainforests during the last 4500 cal yr BP. These pollen records indicate that the coastal savannas of western equatorial Africa did not exist during the mid-Holocene and instead the region was covered by evergreen rainforests. From ca. 4000 cal yr BP a progressive decline of inland evergreen rainforest, accompanied by the expansion of semi-deciduous rainforest, occurred synchronously with grassland colonisation in the coastal region of Gabon. The contraction of moist evergreen rainforest and the establishment of coastal savannas in Gabon suggest decreasing humidity from ca. 4000 cal yr BP. The marked reduction in evergreen rainforest and subsequent savanna expansion was followed from 2700 cal yr BP by the colonization of secondary forests dominated by the palm, Elaeis guineensis, and the shrub, Alchornea cordifolia (Euphorbiaceae. A return to wetter climatic conditions from about 1400 cal yr BP led to the renewed spread of evergreen rainforest inland, whereas a forest-savanna mosaic still persists in the coastal region. There is no evidence to suggest that the major environmental changes observed were driven by human impact.

  16. IDESSA: An Integrative Decision Support System for Sustainable Rangeland Management in Southern African Savannas

    Science.gov (United States)

    Meyer, Hanna; Authmann, Christian; Dreber, Niels; Hess, Bastian; Kellner, Klaus; Morgenthal, Theunis; Nauss, Thomas; Seeger, Bernhard; Tsvuura, Zivanai; Wiegand, Kerstin

    2017-04-01

    Bush encroachment is a syndrome of land degradation that occurs in many savannas including those of southern Africa. The increase in density, cover or biomass of woody vegetation often has negative effects on a range of ecosystem functions and services, which are hardly reversible. However, despite its importance, neither the causes of bush encroachment, nor the consequences of different resource management strategies to combat or mitigate related shifts in savanna states are fully understood. The project "IDESSA" (An Integrative Decision Support System for Sustainable Rangeland Management in Southern African Savannas) aims to improve the understanding of the complex interplays between land use, climate patterns and vegetation dynamics and to implement an integrative monitoring and decision-support system for the sustainable management of different savanna types. For this purpose, IDESSA follows an innovative approach that integrates local knowledge, botanical surveys, remote-sensing and machine-learning based time-series of atmospheric and land-cover dynamics, spatially explicit simulation modeling and analytical database management. The integration of the heterogeneous data will be implemented in a user oriented database infrastructure and scientific workflow system. Accessible via web-based interfaces, this database and analysis system will allow scientists to manage and analyze monitoring data and scenario computations, as well as allow stakeholders (e. g. land users, policy makers) to retrieve current ecosystem information and seasonal outlooks. We present the concept of the project and show preliminary results of the realization steps towards the integrative savanna management and decision-support system.

  17. Climate variability and impacts on east African livestock herders: The Maasai of Ngorongoro Conservation Area, Tanzania

    OpenAIRE

    Galvin, K.A.; Thornton, P.K.; Boone, R.B.; Sunderland, J.

    2004-01-01

    Metadata only record East African pastoral adaptation and vulnerability to climate variability and climate change is assessed, using data from decision-making processes and ecological data of the Maasai of Ngorongoro Conservation Area as an example. The paper uses integrated modeling, linking PHEWS, a household model, to SAVANNA, an ecosystem model to look at the effects of drought and a series of wet years on the well-being of Maasai pastoralists. Model results suggest that the ecosystem ...

  18. Intra-seasonal risk of agriculturally-relevant weather extremes in West African Sudan Savanna

    Science.gov (United States)

    Boansi, David; Tambo, Justice A.; Müller, Marc

    2018-01-01

    Using household survey data and historical daily climate data for 29 communities across Upper East Ghana and Southwest Burkina Faso, we document climatic conditions deemed major threat to farming in the West African Sudan Savanna and assess risks posed by such conditions over the period 1997-2014. Based on farmers' perception, it is found that drought, low rainfall, intense precipitation, flooding, erratic rainfall pattern, extremely high temperatures, delayed rains, and early cessation of rains are the major threats farmers face. Using first-order Markov chain model and relevant indices for monitoring weather extremes, it is discovered that climatic risk is a general inherent attribute of the rainy season in the study area. Due to recent changes in onset of rains and length of the rainy season, some farmers have either resorted to early planting of drought-hardy crops, late planting of drought-sensitive crops, or spreading of planting across the first 3 months of the season to moderate harm. Each of these planting decisions however has some risk implications. The months of May, June, and October are found to be more susceptible to relatively longer duration of dry and hot spells, while July, August, and September are found to be more susceptible to intense precipitation and flooding. To moderate harm from anticipated weather extremes, farmers need to adjust their cropping calendar, adopt appropriate crop varieties, and implement soil and water management practices. For policy makers and other stakeholders, we recommend the supply of timely and accurate weather forecasts to guide farmers in their seasonal cropping decisions and investment in/installation of low cost irrigation facilities to enhance the practice of supplemental irrigation.

  19. Journal of East African Natural History

    African Journals Online (AJOL)

    The Journal of East African Natural History is published jointly by the East Africa Natural History Society and the National Museums of Kenya. The Journal publishes papers and notes in the field of natural history, broadly defined as the study of organisms in their natural state, relevant to the eastern African region.

  20. Trace gas emissions to the atmosphere by biomass burning in the west African savannas

    Science.gov (United States)

    Frouin, Robert J.; Iacobellis, Samuel F.; Razafimpanilo, Herisoa; Somerville, Richard C. J.

    1994-01-01

    Savanna fires and atmospheric carbon dioxide (CO2) detection and estimating burned area using Advanced Very High Resolution Radiometer_(AVHRR) reflectance data are investigated in this two part research project. The first part involves carbon dioxide flux estimates and a three-dimensional transport model to quantify the effect of north African savanna fires on atmospheric CO2 concentration, including CO2 spatial and temporal variability patterns and their significance to global emissions. The second article describes two methods used to determine burned area from AVHRR data. The article discusses the relationship between the percentage of burned area and AVHRR channel 2 reflectance (the linear method) and Normalized Difference Vegetation Index (NDVI) (the nonlinear method). A comparative performance analysis of each method is described.

  1. East African Journal of Sciences: Submissions

    African Journals Online (AJOL)

    Aims The East African Journal of Sciences (EAJS) publishes original scientific ... of ideas among scientists engaged in research and development activities; and ... font size 12, Times New Roman), including tables, figures and illustrations.

  2. Scientific Communication | Okolo | East African Medical Journal

    African Journals Online (AJOL)

    East African Medical Journal. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 92, No 2 (2015) >. Log in or Register to get access to full text downloads.

  3. East African Agricultural and Forestry Journal

    African Journals Online (AJOL)

    East African Agricultural and Forestry Journal is published by the Kenya ... water resource base to meet the challenges of poverty alleviation and food security. ... on maize growth, nitrogen uptake and yield in a semi-arid Kenyan environment ...

  4. Humans and elephants as treefall drivers in African savannas

    CSIR Research Space (South Africa)

    Mograbi, PJ

    2017-01-01

    Full Text Available and composition refl ect the ecological context of multiple spatial and temporal pro- cesses (Watt 1947, Vanak et al. 2012, Scholtz et al. 2014), complex interactive eff ects with other species (Dean et al. 1999, Sankaran et al. 2005), humans (Turner et al.... Southern African fi re regimes as revealed by remote sensing. – Int. J. Wildland Fire 19: 861 – 878. Archibald, S. et al. 2013. Defi ning pyromes and global syndromes of fi re regimes. – Proc. Natl Acad. Sci. USA 110: 6442 – 6447. Asner, G. P...

  5. The East African rift system

    Science.gov (United States)

    Chorowicz, Jean

    2005-10-01

    This overview paper considers the East African rift system (EARS) as an intra-continental ridge system, comprising an axial rift. It describes the structural organization in three branches, the overall morphology, lithospheric cross-sections, the morphotectonics, the main tectonic features—with emphasis on the tension fractures—and volcanism in its relationships with the tectonics. The most characteristic features in the EARS are narrow elongate zones of thinned continental lithosphere related to asthenospheric intrusions in the upper mantle. This hidden part of the rift structure is expressed on the surface by thermal uplift of the rift shoulders. The graben valleys and basins are organized over a major failure in the lithospheric mantle, and in the crust comprise a major border fault, linked in depth to a low angle detachment fault, inducing asymmetric roll-over pattern, eventually accompanied by smaller normal faulting and tilted blocks. Considering the kinematics, divergent movements caused the continent to split along lines of preexisting lithospheric weaknesses marked by ancient tectonic patterns that focus the extensional strain. The hypothesis favored here is SE-ward relative divergent drifting of a not yet well individualized Somalian plate, a model in agreement with the existence of NW-striking transform and transfer zones. The East African rift system comprises a unique succession of graben basins linked and segmented by intracontinental transform, transfer and accommodation zones. In an attempt to make a point on the rift system evolution through time and space, it is clear that the role of plume impacts is determinant. The main phenomenon is formation of domes related to plume effect, weakening the lithosphere and, long after, failure inducing focused upper mantle thinning, asthenospheric intrusion and related thermal uplift of shoulders. The plume that had formed first at around 30 Ma was not in the Afar but likely in Lake Tana region (Ethiopia

  6. Termites and large herbivores influence seed removal rates in an African savanna.

    Science.gov (United States)

    Acanakwo, Erik Francis; Sheil, Douglas; Moe, Stein R

    2017-12-01

    Seed removal can influence plant community dynamics, composition, and resulting vegetation characteristics. In the African savanna, termites and large herbivores influence vegetation in various ways, likely including indirect effects on seed predators and secondary dispersers. However, the intensity and variation of seed removal rates in African savannas has seldom been studied. We experimentally investigated whether termites and large herbivores were important factors in the mechanisms contributing to observed patterns in tree species composition on and off mounds, in Lake Mburo National Park, Uganda. Within fenced (excluding large herbivores) and unfenced termite mound and adjacent savanna plots, we placed seeds of nine native tree species within small open "cages," accessed by all animals, roofed cages that only allowed access to small vertebrates and invertebrates, and closed cages that permitted access by smaller invertebrates only (5 mm wire mesh). We found that mean seed removal rate was high (up to 87.3% per 3 d). Mound habitats experienced significantly higher removal rates than off-mound habitats. The mean removal rate of native seeds from closed cages was 11.1% per 3 d compared with 19.4% and 23.3% removed per 3 d in the roofed and open cages, respectively. Smaller seeds experienced higher removal rates than larger seeds. Large herbivore exclusion on mounds reduced native seed removal rates by a mean of 8.8% in the open cages, but increased removal rates by 1.7% in the open cages when off-mound habitats were fenced. While removal rates from open cages were higher on active mounds (30.9%) than on inactive mounds (26.7%), the removal rates from closed cages were lower on active vs. inactive mounds (6.1% vs. 11.6%, respectively). Thus, we conclude that large herbivores and Macrotermes mounds influence seed removal rates, though these effects appear indirect. © 2017 by the Ecological Society of America.

  7. Effects of repeated burning on woody vegetation structure and composition in a semi-arid southern African savanna

    NARCIS (Netherlands)

    Gandiwa, E.

    2011-01-01

    The objective of this study was to investigate the effects of repeated dry season annual hot fires on woody plants in a semiarid southern African savanna in Zimbabwe. Parts of the National University of Science and Technology (NUST) research fields in Bulawayo, Zimbabwe have been burnt annually in

  8. Portulacaria afra in East AFrica | Newton | Journal of East African ...

    African Journals Online (AJOL)

    No Abstract. East African Journal of Natural History Vol. 96 (1) 2007: pp. 107-108. http://dx.doi.org/10.2982/0012-8317(2007)96[107:PAIEA]2.0.CO;2 · AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions of Use ...

  9. East African Journal of Public Health: Journal Sponsorship

    African Journals Online (AJOL)

    East African Journal of Public Health: Journal Sponsorship. Journal Home > About the Journal > East African Journal of Public Health: Journal Sponsorship. Log in or Register to get access to full text downloads.

  10. Scopus: Journal of East African Ornithology: Journal Sponsorship

    African Journals Online (AJOL)

    Scopus: Journal of East African Ornithology: Journal Sponsorship. Journal Home > About the Journal > Scopus: Journal of East African Ornithology: Journal Sponsorship. Log in or Register to get access to full text downloads.

  11. East and Central African Journal of Surgery: About this journal

    African Journals Online (AJOL)

    East and Central African Journal of Surgery: About this journal. Journal Home > East and Central African Journal of Surgery: About this journal. Log in or Register to get access to full text downloads.

  12. Archives: East and Central African Journal of Surgery

    African Journals Online (AJOL)

    Items 1 - 40 of 40 ... Archives: East and Central African Journal of Surgery. Journal Home > Archives: East and Central African Journal of Surgery. Log in or Register to get access to full text downloads.

  13. East African Journal of Statistics

    African Journals Online (AJOL)

    AFRICAN JOURNALS ONLINE (AJOL) · Journals · Advanced Search · USING ... EASJOSTA publishes the latest findings in applied and theoretical statistics. ... mathematics and acturial sciences, all considered as part of applied statistics.

  14. East African rarities committee report | Fisher | Scopus: Journal of ...

    African Journals Online (AJOL)

    East African Rarities Committee (EARC) Special Report Species included for East African countries in Britton (1980) which have since been considered unacceptable. East African Rarities Committee Report 2013–2015. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD ...

  15. Journal of East African Natural History: Submissions

    African Journals Online (AJOL)

    2017-11-01

    Nov 1, 2017 ... Author Guidelines. Submission: manuscripts should be submitted as a Word document in an email attachment, to the Editor-in-Chief, Journal of East African Natural History at office@naturekenya.org. The manuscript should be accompanied by a covering letter from the author, or in the case of multiple ...

  16. East African Journal of Sciences: Editorial Policies

    African Journals Online (AJOL)

    Open Access Policy. This journal provides immediate open access to its content, upon registration, on the principle that making research freely available to the public supports a greater global exchange of knowledge. Creative Commons License East African Journal of Sciences by Haramaya University is licensed under a ...

  17. East African Journal of Public Health

    African Journals Online (AJOL)

    The East African Journal of Public Health is a multi-disciplinary journal publishing scientific research work from a range of public health related disciplines including community medicine, epidemiology, nutrition, behavioural sciences, health promotion, health education, communicable and non-communicable disease.

  18. Assessing sanitary mixtures in East African cities

    NARCIS (Netherlands)

    Letema, S.C.

    2012-01-01

    The urbanisation of poverty and informality in East African cities poses a threat to environmental
    health, perpetuates social exclusion and inequalities, and creates service gaps (UN-Habitat, 2008).
    This makes conventional sanitation provision untenable citywide, giving rise to the

  19. Regional Integration: A Political Federation of the East African ...

    African Journals Online (AJOL)

    The aim of this paper is to explore the possibility and viability of an East African political federation project. Since the late 1800s under the then British East Africa, the countries of East Africa have been searching for ways to integrate. The search led to the establishment of the East African Community (EAC) in December ...

  20. Archives: East African Medical Journal

    African Journals Online (AJOL)

    Items 1 - 50 of 228 ... AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions of Use · Contact AJOL · News. OTHER RESOURCES... for Researchers · for Journals · for Authors · for Policy Makers · about Open Access ...

  1. African Muslim Youth and the Middle East

    DEFF Research Database (Denmark)

    Ihle, Annette Haaber

    this African tradition of religious scholarship in the Middle East. The paper will, with the help of Pierre Bourdieu's notion of forms of capital related to various fields, analyse the challenges which Muslim students encounter during their stay in the Middle East and the forms of capital they bring back......, marked by economic decline and political instability. In Africa a weak or even failed state often means that young people have in reality no access to political, educational or economic positions and resources. In some countries like Nigeria, Ghana and the Ivory Coast the marginalisation of the youth...

  2. Projections of 21st Century African Climate: Implications for African Savanna Fire Dynamics, Human Health and Food Security

    Science.gov (United States)

    Adegoke, J. O.

    2015-12-01

    Fire is a key agent of change in the African savannas, which are shaped through the complex interactions between trees, C4 grasses, rainfall, temperature, CO2 and fire. These fires and their emitted smoke can have numerous direct and indirect effects on the environment, water resources, air quality, and climate. For instance, veld fires in southern Africa cause large financial losses to agriculture, livestock production and forestry on an annual basis. This study contributes to our understanding of the implications of projected surface temperature evolution in Africa for fire risk, human health and agriculture over the coming decades. We use an ensemble of high-resolution regional climate model simulations of African climate for the 21st century. Regional dowscalings and recent global circulation model projections obtained for Africa indicate that African temperatures are likely to rise at 1.5 times the global rate of temperature increase in the tropics, and at almost twice the global rate of increase in the subtropics. Warming is projected to occur during the 21st century, with increases of 4-6 °C over the subtropics and 3-5 °C over the tropics plausible by the end of the century relative to present-day climate under the A2 (low mitigation) scenario. We explore the significance of the projected warming by documenting increases in projected high fire danger days and heat-wave days. General drying is projected across the continent, even for areas (e.g. tropical Africa) where an increase in rainfall is plausible. This is due to the drastic increases in temperature that are projected, which leads to drier soils (through enhanced evaporation) despite the rainfall increases. This will likely impact negatively on crop yield, particularly on the maize crop that is of crucial importance in terms of African food security.

  3. Collaboration with East African security organisations

    DEFF Research Database (Denmark)

    Nordby, Johannes Riber; Jacobsen, Katja L.

    2012-01-01

    of the concept. At the same time the three organisations represent different constellations of member nations and thus different national interests, and locally they have different legitimacy and political strength. Thus, when choosing collaboration partners for a security project it is not simply a question......When it comes to understanding the concept of security and the way fragile security situations should be solved, the difference is big. While EASF – the East African Standby Force – is a regular military force with a rather traditional, military perception of the concept of security, EAC (East...... African Community) and IGAD (Intergovernmental Authority on Development) have broader perceptions of the concept. According to EAC, security also concerns matters such as policy reform, legislation, education and infrastructure. IGAD considers food security and environmental and economic issues as part...

  4. Frequent burning promotes invasions of alien plants into a mesic African savanna

    NARCIS (Netherlands)

    Masocha, M.; Skidmore, A.K.; Poshiwa, X.; Prins, H.H.T.

    2011-01-01

    Fire is both inevitable and necessary for maintaining the structure and functioning of mesic savannas. Without disturbances such as fire and herbivory, tree cover can increase at the expense of grass cover and over time dominate mesic savannas. Consequently, repeated burning is widely used to

  5. Synergistic effects of fire and elephants on arboreal animals in an African savanna.

    Science.gov (United States)

    Pringle, Robert M; Kimuyu, Duncan M; Sensenig, Ryan L; Palmer, Todd M; Riginos, Corinna; Veblen, Kari E; Young, Truman P

    2015-11-01

    Disturbance is a crucial determinant of animal abundance, distribution and community structure in many ecosystems, but the ways in which multiple disturbance types interact remain poorly understood. The effects of multiple-disturbance interactions can be additive, subadditive or super-additive (synergistic). Synergistic effects in particular can accelerate ecological change; thus, characterizing such synergies, the conditions under which they arise, and how long they persist has been identified as a major goal of ecology. We factorially manipulated two principal sources of disturbance in African savannas, fire and elephants, and measured their independent and interactive effects on the numerically dominant vertebrate (the arboreal gekkonid lizard Lygodactylus keniensis) and invertebrate (a guild of symbiotic Acacia ants) animal species in a semi-arid Kenyan savanna. Elephant exclusion alone (minus fire) had negligible effects on gecko density. Fire alone (minus elephants) had negligible effects on gecko density after 4 months, but increased gecko density twofold after 16 months, likely because the decay of fire-damaged woody biomass created refuges and nest sites for geckos. In the presence of elephants, fire increased gecko density nearly threefold within 4 months of the experimental burn; this occurred because fire increased the incidence of elephant damage to trees, which in turn improved microhabitat quality for geckos. However, this synergistic positive effect of fire and elephants attenuated over the ensuing year, such that only the main effect of fire was evident after 16 months. Fire also altered the structure of symbiotic plant-ant assemblages occupying the dominant tree species (Acacia drepanolobium); this influenced gecko habitat selection but did not explain the synergistic effect of fire and elephants. However, fire-driven shifts in plant-ant occupancy may have indirectly mediated this effect by increasing trees' susceptibility to elephant damage. Our

  6. Increased tree densities in South African savannas: >50 years of data suggests CO2 as driver

    CSIR Research Space (South Africa)

    Buitenwerf, R

    2012-02-01

    Full Text Available EC et al. (2007) Effects of four decades of fire manipulation on woody vegetation structure in savanna. Ecology, 88, 1119-1125. Hoffman MT, O'Connor TG (1999) Vegetation change over 40 years in the Weenen/Muden area, KwaZulu-Natal: evidence from... response of savanna woody plant species following harvesting: the value of persistence. Forest Ecology and Management, 232, 114-123. O'Connor TG (1985) A synthesis of field experiments concerning the grass layer in the savanna regions of southern...

  7. Cerebral cortices of East african early hominids.

    Science.gov (United States)

    Falk, D

    1983-09-09

    An endocast of the frontal lobe of a reconstructed skull, which is approximately 2 million years old, from the Koobi Fora region of Kenya appears to represent the oldest human-like cortical sulcal pattern in the fossil record, while the endocast from another skull from the same region produces an endocast that appears apelike in its frontal lobe and similar to endocasts from earlier South African australopithecines. New analysis of paleoanatomical evidence thus indicates that at least two taxa of early hominids coexisted in East Africa.

  8. Nylsvley - South African Savanna ecosystem project: objectives, organisation and research programme

    CSIR Research Space (South Africa)

    Huntley, BJ

    1978-03-01

    Full Text Available A description of the objectives, organization and research programme of the Savanna Ecosystem Project being undertaken at Nylsvley in the northern Transvaal is presented. The project is a cooperative multi-disciplinary study of the structure...

  9. Multiple Scales of Control on the Structure and Spatial Distribution of Woody Vegetation in African Savanna Watersheds.

    Directory of Open Access Journals (Sweden)

    Nicholas R Vaughn

    Full Text Available Factors controlling savanna woody vegetation structure vary at multiple spatial and temporal scales, and as a consequence, unraveling their combined effects has proven to be a classic challenge in savanna ecology. We used airborne LiDAR (light detection and ranging to map three-dimensional woody vegetation structure throughout four savanna watersheds, each contrasting in geologic substrate and climate, in Kruger National Park, South Africa. By comparison of the four watersheds, we found that geologic substrate had a stronger effect than climate in determining watershed-scale differences in vegetation structural properties, including cover, height and crown density. Generalized Linear Models were used to assess the spatial distribution of woody vegetation structural properties, including cover, height and crown density, in relation to mapped hydrologic, topographic and fire history traits. For each substrate and climate combination, models incorporating topography, hydrology and fire history explained up to 30% of the remaining variation in woody canopy structure, but inclusion of a spatial autocovariate term further improved model performance. Both crown density and the cover of shorter woody canopies were determined more by unknown factors likely to be changing on smaller spatial scales, such as soil texture, herbivore abundance or fire behavior, than by our mapped regional-scale changes in topography and hydrology. We also detected patterns in spatial covariance at distances up to 50-450 m, depending on watershed and structural metric. Our results suggest that large-scale environmental factors play a smaller role than is often attributed to them in determining woody vegetation structure in southern African savannas. This highlights the need for more spatially-explicit, wide-area analyses using high resolution remote sensing techniques.

  10. Crowdfunding in Emerging Markets : Lessons from East African Startups

    OpenAIRE

    World Bank Group

    2015-01-01

    The purpose of this paper is to capture lessons learned from East African entrepreneurs who were some of crowdfunding’s first adopters. Their experiences can serve as a practical guide for entrepreneurs looking to more effectively utilize crowdfunding across all emerging markets. In order to gather this data, the World Bank conducted interviews with a number of East African technology entr...

  11. Journal of East African Natural History: Editorial Policies

    African Journals Online (AJOL)

    Focus and Scope. The Journal of East African Natural History is published jointly by the East Africa Natural History Society and the National Museums of Kenya. The Journal publishes papers and notes in the field of natural history, broadly defined as the study of organisms in their natural state, relevant to the eastern African ...

  12. Nutrient and Light Limitations on Grass Productivity in a Southern African Savanna

    Science.gov (United States)

    Ries, L. P.; Shugart, H. H.; Caylor, K. K.; Okin, G. S.; Kgope, B.

    2006-12-01

    Despite the ubiquity of sub-tropical savannas throughout the earth, limitations of savanna productivity are understudied relative to other terrestrial systems. In particular, there has been little attention on the role of phosphorus (P) in savanna productivity and structure. This study examined the role of increased nitrogen (N) and P in grass productivity in a woodland savanna in Botswana. We added aqueous forms of N and P individually and together to selected grasses. During the following growing season we measured foliar nutrient concentrations, aboveground biomass productivity and photosynthetic response at various levels of incident photosynthetically active radiation to estimate the productivity response. As expected, we observed an increase in foliar P concentrations in P and N+P treatments. However, there was no increase in foliar N for any treatments. We also observed a significant increase in net carbon assimilation and Amax for all treatments relative to the control grasses. Despite a higher rate of leaf level carbon assimilation in the N treatment, the aboveground biomass production was smaller than that of the N+P treatment. These results suggest that the aboveground productivity of these woodland savanna grasses is limited by both N and P. Additionally, under constant CO2 availability, photosynthesis appears to be limited by nutrients for light levels greater than 500 μmol m-2s-1. This research will help broaden our understanding of the biogeochemical processes that govern savanna productivity. Ultimately, these data can be used to model canopy productivity and ecological succession of savannas under scenarios in which bush encroachment and desertification may alter light and nutrients availability.

  13. Tobacco smoking in black and white South Africans | Peltzer | East ...

    African Journals Online (AJOL)

    Tobacco smoking in black and white South Africans. K. Peltzer. Abstract. (East African Medical Journal: 2001 78(3): 115-118). Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT · http://dx.doi.org/10.4314/eamj.v78i3.9074 · AJOL African Journals Online.

  14. Determinants of seasonal changes in availability of food patches for elephants (Loxodonta africana in a semi-arid African savanna

    Directory of Open Access Journals (Sweden)

    Bruce W. Clegg

    2017-06-01

    Full Text Available Loss of biodiversity caused by impact of elephants (Loxodonta africana on African woodlands may require a management response, but any action should be based on an understanding of why elephants choose to utilise trees destructively. Comprehension of elephant feeding behaviour requires consideration of the relative value of the plant groups they may potentially consume. Profitability of available food is partly determined by the time to locate a food patch and, therefore, as a foundation for understanding the influence of food availability on diet selection, key controls on the density of grass, forb, and browse patches were investigated across space and time in a semi-arid African savanna. Density of food patches changed seasonally because plant life-forms required different volumes of soil water to produce green forage; and woody plants and forbs responded to long-term changes in soil moisture, while grasses responded to short-term moisture pulses. Soil texture, structure of woody vegetation and fire added further complexity by altering the soil water thresholds required for production of green forage. Interpolating between regularly-timed, ground-based measurements of food density by using modelled soil water as the predictor in regression equations may be a feasible method of quantifying food available to elephants in complex savanna environments.

  15. Competition between a Lawn-Forming Cynodon dactylon and a Tufted Grass Species Hyparrhenia hirta on a South-African Dystrophic Savanna

    NARCIS (Netherlands)

    Zwerts, J.A.; Prins, H.H.T.; Bomhoff, D.; Verhagen, I.; Swart, J.M.; Boer, de W.F.

    2015-01-01

    South African savanna grasslands are often characterised by indigestible tufted grass species whereas lawn grasses are far more desirable in terms of herbivore sustenance. We aimed to investigate the role of nutrients and/or the disturbance (grazing, trampling) by herbivores on the formation of

  16. Trophic interactions among invertebrates in termitaria in the African savanna : a stable isotope approach

    NARCIS (Netherlands)

    De Visser, Sarah N.; Freymann, Bernd P.; Schnyder, Hans

    2008-01-01

    1. Termites (Isoptera) in tropical savannas are known as ecosystem engineers, affecting the spatial and temporal distribution of water, carbon, cations, and nutrients through their mound structures. Their mounds, however, also offer habitation to diverse taxa and feeding guilds of other

  17. Improved quality of beneath-canopy grass in South African savannas: Local and seasonal variation

    NARCIS (Netherlands)

    Treydte, A.C.; Looringh van Beeck, F.A.; Ludwig, F.; Heitkonig, I.M.A.

    2008-01-01

    Questions: Do large trees improve the nutrient content and the structure of the grass layer in savannas? Does the magnitude of this improvement differ with locality ( soil nutrients) and season ( water availability)? Are grass structure and species composition beneath tree canopies influenced by

  18. Estimating and mapping grass phosphorus concentration in an African savanna using hyperspectral image data

    NARCIS (Netherlands)

    Mutanga, O.; Kumar, L.

    2007-01-01

    We tested the utility of imaging spectroscopy and neural networks to map phosphorus concentration in savanna grass using airborne HyMAP image data. We also sought to ascertain the key wavelengths for phosphorus prediction using hyperspectral remote sensing. The remote sensing of foliar phosphorus

  19. The importance of herbivore interactions for the dynamics of African savanna woodlands : an hypothesis

    NARCIS (Netherlands)

    Van de Koppel, J; Prins, HHT

    Current hypotheses to explain dynamic transitions between savanna grasslands and woodlands in Africa focus on grazing by elephant or the influence of fire. Using a simple mathematical model, this paper argues that interactions between small herbivores such as impala or buffalo and large herbivores

  20. Assessing effect of rainfall on rate of alien shrub expansion in a southern African savanna

    NARCIS (Netherlands)

    Masocha, Mhosisi; Dube, Timothy; Skidmore, A.K.; Holmgren, Milena; Prins, Herbert

    2017-01-01

    Understanding the environmental factors governing the spread of alien shrubs is crucial for conserving biodiversity. In the semi-arid savannas of Africa, alien shrub invasion often occurs simultaneously with native shrub encroachment but climate-dependent differences in encroachments of native and

  1. Records: East African Rarities Committee report and change of remit ...

    African Journals Online (AJOL)

    Scopus: Journal of East African Ornithology. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 29 (2009) >. Log in or Register to get access to full text downloads.

  2. Short communications | Mockler | Scopus: Journal of East African ...

    African Journals Online (AJOL)

    Scopus: Journal of East African Ornithology. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 36, No 1 (2016) >. Log in or Register to get access to full text downloads.

  3. Systematic and taxonomic issues concerning some East African bird ...

    African Journals Online (AJOL)

    Scopus: Journal of East African Ornithology. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 34 (2015) >. Log in or Register to get access to full text downloads.

  4. General practitioners and clinical guidelines | Bhagat | East African ...

    African Journals Online (AJOL)

    East African Medical Journal. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 78, No 1 (2001) >. Log in or Register to get access to full text downloads.

  5. Stable isotopic composition of East African lake waters

    International Nuclear Information System (INIS)

    Odada, E.O.

    2001-01-01

    The investigation of stable isotopic composition of East African lake waters was conducted by scientists from the Department of Geology, University of Nairobi, as part of the International Decade for the East African Lakes (IDEAL) project and in close collaboration with the scientists from Large Lakes Observatory of the University of Minnesota and the Isotope Hydrology Laboratory of the IAEA in Vienna. The Research Contract was part of the IAEA Co-ordinated Research Programme on Isotope Techniques in Lake Dynamics Investigations, and was sponsored by the Agency. Water and grab sediment samples were obtained from East African Lakes during the month of January and February 1994 and July/August 1995. Water samples were analysed for oxygen and deuterium isotopic composition at the IAEA Laboratories in Vienna, Austria. In this final paper we report the results of the study of oxygen and deuterium isotopic composition from the East African lake waters. (author)

  6. Climate variability and impacts on east African livestock herders: the ...

    African Journals Online (AJOL)

    Climate variability and impacts on east African livestock herders: the Maasai of ... and vulnerability to climate variability and climate change is assessed, using data ... Model results suggest that the ecosystem is quite resilient and suggests that ...

  7. East African discourses on khat and sex.

    Science.gov (United States)

    Beckerleg, Susan

    2010-12-01

    The study aims to review and analyse the varied East African discourses on the effects of khat use on libido, fertility, transmission of HIV, prostitution and rape. The data were gathered between 2004 and 2009 in Kenya and Uganda. Between 2004 and 2005 across Kenya and Uganda a broad survey approach was adopted, involving identification of and travel to production areas, interviews with producers and consumers in rural and urban settings. In addition, a survey of 300 Ugandan consumers was carried out in late 2004. Between 2007 and 2009, an in-depth study of khat production, trade and consumption was conducted in Uganda. This study also employed a mixture of methods, including key informant interviews participant-observation and a questionnaire survey administered to 210 khat consumers. Khat is associated, by consumers and its detractors alike, with changes in libido and sexual performance. Although there is no evidence to support their claims, detractors of khat use argue that khat causes sexual violence, causes women to enter sex work, and that chewing causes the spread of sexually transmitted diseases, including the HIV virus. In East Africa the discourse on khat and sex has led to consumption of the substances being associated by many people with uncontrolled sexual behaviour. There is no evidence that khat use fuels promiscuity, commercial sex, sexually transmitted diseases or rape. The current discourse on khat and sex touches on all these topics. Local religious and political leaders invoke khat use as a cause of what they argue is a breakdown of morals and social order. In Kenya and Uganda it is women khat consumers who are seen as sexually uncontrolled. In Uganda, the argument is extended even to men: with male khat chewers labelled as prone to commit rape. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  8. Breakdown of an ant-plant mutualism follows the loss of large herbivores from an African savanna.

    Science.gov (United States)

    Palmer, Todd M; Stanton, Maureen L; Young, Truman P; Goheen, Jacob R; Pringle, Robert M; Karban, Richard

    2008-01-11

    Mutualisms are key components of biodiversity and ecosystem function, yet the forces maintaining them are poorly understood. We investigated the effects of removing large mammals on an ant-Acacia mutualism in an African savanna. Ten years of large-herbivore exclusion reduced the nectar and housing provided by plants to ants, increasing antagonistic behavior by a mutualistic ant associate and shifting competitive dominance within the plant-ant community from this nectar-dependent mutualist to an antagonistic species that does not depend on plant rewards. Trees occupied by this antagonist suffered increased attack by stem-boring beetles, grew more slowly, and experienced doubled mortality relative to trees occupied by the mutualistic ant. These results show that large mammals maintain cooperation within a widespread symbiosis and suggest complex cascading effects of megafaunal extinction.

  9. Spatial Heterogeneity and Sources of Soil Carbon in Southern African Savannas

    Science.gov (United States)

    Macko, S.; Wang, L.; Okin, G.

    2007-12-01

    Soil organic carbon (SOC) is one of the largest and most dynamic reservoirs of C on Earth, with nearly twice as much C stored in SOC than in the biosphere and atmosphere combined. SOC storage in global tropical savannas constitutes approximately 56 Gt of C, which rises to 216 Gt of C (i.e., about 17% of the terrestrial non- agricultural SOC), when woodlands, shrublands, and desert scrub are included. Savannas cover about 20% of the global land surface, including about one-half of Africa, Australia and South America. The shared dominance of trees and grasses in savannas, the dominant physiognomy in southern Africa, add more complexity to soil C pool partitioning and dynamics than is found in landscapes with a single physiognomy. Here, the spatial variability of the soil C pool was investigated with particular emphasis on understanding the contribution to SOC from trees and grasses at two savanna sites of the Kalahari Transect, one wet and the other dry. Using a combination of stable isotope techniques and geostatistics, the results showed that spatial patterns of soil δ13 C exist and were related to the distributions of woody (C3) and herbaceous (C4) vegetation at both sites. Heterogeneity of the sources of SOC, as well as heterogeneity in the amount of SOC, was greater at the dry site relative to the wet site. At the dry site, the grasses were the major contributor to soil C whereas in the wet site, woody vegetation was the major contributor, regardless of the location with respect to woody canopies.

  10. Topo-edaphic controls over woody plant biomass in South African savannas

    Directory of Open Access Journals (Sweden)

    M. S. Colgan

    2012-05-01

    Full Text Available The distribution of woody biomass in savannas reflects spatial patterns fundamental to ecosystem processes, such as water flow, competition, and herbivory, and is a key contributor to savanna ecosystem services, such as fuelwood supply. While total precipitation sets an upper bound on savanna woody biomass, the extent to which substrate and terrain constrain trees and shrubs below this maximum remains poorly understood, often occluded by local-scale disturbances such as fire and trampling. Here we investigate the role of hillslope topography and soil properties in controlling woody plant aboveground biomass (AGB in Kruger National Park, South Africa. Large-area sampling with airborne Light Detection and Ranging (LiDAR provided a means to average across local-scale disturbances, revealing an unexpectedly linear relationship between AGB and hillslope-position on basalts, where biomass levels were lowest on crests, and linearly increased toward streams (R2 = 0.91. The observed pattern was different on granite substrates, where AGB exhibited a strongly non-linear relationship with hillslope position: AGB was high on crests, decreased midslope, and then increased near stream channels (R2 = 0.87. Overall, we observed 5-to-8-fold lower AGB on clayey, basalt-derived soil than on granites, and we suggest this is due to herbivore-fire interactions rather than lower hydraulic conductivity or clay shrinkage/swelling, as previously hypothesized. By mapping AGB within and outside fire and herbivore exclosures, we found that basalt-derived soils support tenfold higher AGB in the absence of fire and herbivory, suggesting high clay content alone is not a proximal limitation on AGB. Understanding how fire and herbivory contribute to AGB heterogeneity is critical to predicting future savanna carbon storage under a changing climate.

  11. General practitioners and clinical guidelines | Bhagat | East African ...

    African Journals Online (AJOL)

    East African Medical Journal: 2001 78(1): 30-34). Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT · http://dx.doi.org/10.4314/eamj.v78i1.9109 · AJOL African Journals Online.

  12. Acute appendicitis in a Kenya rural hospital | Willmore | East African ...

    African Journals Online (AJOL)

    East African Medical Journal: 2001 78(7): 355-357). Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT · http://dx.doi.org/10.4314/eamj.v78i7.9007 · AJOL African Journals Online.

  13. East and Central African Journal of Surgery: Contact

    African Journals Online (AJOL)

    Principal Contact. Prof. Ignatius Kakande Editor-in-Chief Association of Surgeons of East Africa. East and Central African Journal of Surgery. P.O. Box 7051. Kampala. Uganda. Alternative email: igkakande@gmail.com. Phone: +256 772 501 745. Email: ecajs@gmail.com ...

  14. The influence of savanna trees on nutrient, water and light availability and the understorey vegetation

    NARCIS (Netherlands)

    Ludwig, F.; Kroon, de H.; Berendse, F.; Prins, H.H.T.

    2004-01-01

    In an East African savanna herbaceous layer productivity and species composition were studied around Acacia tortilis trees of three different age classes, as well as around dead trees and in open grassland patches. The effects of trees on nutrient, light and water availability were measured to

  15. Rainfall and topo-edaphic influences on woody community phenology in South African savannas

    CSIR Research Space (South Africa)

    Shackleton, CM

    1999-03-01

    Full Text Available the limiting periods, i.e. at Stockholm. the start and cessation of the rainy season. This was Fatubarin, A. (1985) Observations on the phenology of not reflected in the data presented here with respect to the woody plants and grasses in a savanna ecosystem... of temperature on evaporative demand (Bate, Furniss & Pendle, 1982).∗ Current address: Environmentek, CSIR, P.O. Box At a gross scale, annual rainfall is a coarse index of395, Pretoria 0001, South Africa. e-mail: csh- ackle@csir.co.za. seasonal plant available...

  16. Middle East and North African Oil.

    Science.gov (United States)

    Al-Quazzaz, Ayad

    1981-01-01

    Traces the history of oil and natural gas in the Middle East and relates the importance of the Middle East's current stores of oil to economic development. Information is presented on the relationship of major oil companies and local governments, OPEC, rate of production, and the impact of oil on the societies of the Middle East and North Africa.…

  17. Phytogeography of the tropical north-east African mountains

    Directory of Open Access Journals (Sweden)

    I. Friis

    1983-11-01

    Full Text Available The tropical north-east African mountains are tentatively divided into four phytochoria, the formal rank of which is not defined. The division is based on patterns of distribution and endemism in the region. The recognition of a distinct Afromontane phytochorion is now well established (Chapman & White, 1970; Werger, 1978; White, 1978. However, there is still very little information on the phytogeography of the individual mountains or mountain systems. This study hopes to fill a little of the gap by analysing distribution patterns and patterns of endemism in the flora of the tropical north-east African mountains. The north-east African mountain system is the largest in tropical Africa (see e.g. map in White, 1978. At the core of this system is the large Ethiopian massif, around which are located various mountains and mountain chains. These include the Red Sea Hills in the Sudan, the mountain chain in northern Somalia, the south-west Arabian mountains, and the Imatong mountains of south-east Sudan. The latter are often referred to the East African mountain system (White, 1978 but. as I will point out later, they also have a close connection with the south-west highlands of Ethiopia. The paper presents some results of my study of the mountain flora of tropical north-east Africa, particularly the forest species. Where no source is indicated, the data are from my own unpublished studies.

  18. Indirect effects of domestic and wild herbivores on butterflies in an African savanna.

    Science.gov (United States)

    Wilkerson, Marit L; Roche, Leslie M; Young, Truman P

    2013-10-01

    Indirect interactions driven by livestock and wild herbivores are increasingly recognized as important aspects of community dynamics in savannas and rangelands. Large ungulate herbivores can both directly and indirectly impact the reproductive structures of plants, which in turn can affect the pollinators of those plants. We examined how wild herbivores and cattle each indirectly affect the abundance of a common pollinator butterfly taxon, Colotis spp., at a set of long-term, large herbivore exclosure plots in a semiarid savanna in central Kenya. We also examined effects of herbivore exclusion on the main food plant of Colotis spp., which was also the most common flowering species in our plots: the shrub Cadaba farinosa. The study was conducted in four types of experimental plots: cattle-only, wildlife-only, cattle and wildlife (all large herbivores), and no large herbivores. Across all plots, Colotis spp. abundances were positively correlated with both Cadaba flower numbers (adult food resources) and total Cadaba canopy area (larval food resources). Structural equation modeling (SEM) revealed that floral resources drove the abundance of Colotis butterflies. Excluding browsing wildlife increased the abundances of both Cadaba flowers and Colotis butterflies. However, flower numbers and Colotis spp. abundances were greater in plots with cattle herbivory than in plots that excluded all large herbivores. Our results suggest that wild browsing herbivores can suppress pollinator species whereas well-managed cattle use may benefit important pollinators and the plants that depend on them. This study documents a novel set of ecological interactions that demonstrate how both conservation and livelihood goals can be met in a working landscape with abundant wildlife and livestock.

  19. Scopus: Journal of East African Ornithology: Contact

    African Journals Online (AJOL)

    Principal Contact. Darcy Ogada Dr Bird Committee of the East Africa Natural History Society. Editors,. Scopus,. c/o Nature Kenya,. P.O. Box 44486,. G.P.O. 00100,. Nairobi, Kenya. Email: scopus@naturekenya.org ...

  20. Herbaceous forage and selection patterns by ungulates across varying herbivore assemblages in a South African savanna

    NARCIS (Netherlands)

    Treydte, A.C.; Baumgartner, S.; Heitkonig, I.M.A.; Grant, C.C.; Getz, W.M.

    2013-01-01

    Herbivores generally have strong structural and compositional effects on vegetation, which in turn determines the plant forage species available. We investigated how selected large mammalian herbivore assemblages use and alter herbaceous vegetation structure and composition in a southern African

  1. Bandwidth selection in smoothing functions | Kibua | East African ...

    African Journals Online (AJOL)

    ... inexpensive and, hence, worth adopting. We argue that the bandwidth parameter is determined by two factors: the kernel function and the length of the smoothing region. We give an illustrative example of its application using real data. Keywords: Kernel, Smoothing functions, Bandwidth > East African Journal of Statistics ...

  2. Genetic structure and diversity of East African taro [ Colocasia ...

    African Journals Online (AJOL)

    Taro [Colocasia esculenta (L) Schott] is mainly produced in Africa by small holder farmers and plays an important role in the livelihood of millions of poor people in less developed countries. The genetic diversity of East African taro has not been determined. This study utilizes six microsatellite primers to analyze five ...

  3. East African Journal of Public Health: Editorial Policies

    African Journals Online (AJOL)

    Focus and Scope. The East African Journal of Public Health is a multi-disciplinary journal publishing scientific research work from a range of public health related disciplines including community medicine, epidemiology, nutrition, behavioural sciences, health promotion, health education, communicable and ...

  4. Adhesive intestinal obstruction | Kuremu | East African Medical Journal

    African Journals Online (AJOL)

    East African Medical Journal. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 83, No 6 (2006) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register · Download this PDF file. The PDF file you selected should ...

  5. Panmixia in east African Platgyra daedalea | Macdonald | Western ...

    African Journals Online (AJOL)

    Reef coral populations in the western Indian Ocean are neglected in terms of research and management. Very little is known about coral population connectivity and dynamics at regional scales. Platygyra daedalea was collected from Indian Ocean coral reefs, mainly from the east African coast between Mombasa Marine ...

  6. Proliferation and Shoot Recovery among the East African Highland ...

    African Journals Online (AJOL)

    Production of East African highland banana (EA-AAA banana) (Musa spp.) is limited by scarcity of planting materials, attributable to their low natural proliferation ability. Under natural field conditions, the EA-AAA bananas greatly differ in suckering ability. In vitro micropropagation has been adopted as an alternative means ...

  7. East African governments' responses to high cereal prices

    NARCIS (Netherlands)

    Meijerink, G.W.; Roza, P.; Berkum, van S.

    2009-01-01

    This study analyses the responses of governments in four East African countries (Kenya, Tanzania, Uganda and Ethiopia) with respect to price formation and price transmission in the cereal sector. All four countries were confronted with high cereal prices in 2008. Government policies applied largely

  8. Editorial : Clinical drug interactions | Kokwaro | East African Medical ...

    African Journals Online (AJOL)

    Journal Home > Vol 78, No 10 (2001) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register. Editorial: Clinical drug interactions. G. O. Kokwaro. Abstract. (East African Medical Journal 2001 78 (10): 505-506). Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT

  9. Alcoholism and diabetes mellitus: Case report | Otieno | East African ...

    African Journals Online (AJOL)

    East African Medical Journal. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 79, No 2 (2002) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register · Download this PDF file. The PDF file you selected should ...

  10. Anorexia nervosa in Kenya | Njenga | East African Medical Journal

    African Journals Online (AJOL)

    East African Medical Journal. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 81, No 4 (2004) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register · Download this PDF file. The PDF file you selected should ...

  11. Acute appendicitis in a Kenya rural hospital | Willmore | East African ...

    African Journals Online (AJOL)

    East African Medical Journal. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 78, No 7 (2001) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register · Download this PDF file. The PDF file you selected should ...

  12. Post-traumatic stress disorder: Case report | Nyamai | East African ...

    African Journals Online (AJOL)

    East African Medical Journal. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 77, No 4 (2000) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register · Download this PDF file. The PDF file you selected should ...

  13. Over grafting donor site | Rogers | East and Central African Journal ...

    African Journals Online (AJOL)

    East and Central African Journal of Surgery. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 14, No 2 (2009) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register. Over grafting donor site. AD Rogers, AK ...

  14. East and Central African Journal of Pharmaceutical Sciences ...

    African Journals Online (AJOL)

    East and Central African Journal of Pharmaceutical Sciences. 1. Vol. 8(2) 40 - 42. Constituents of the Stem Bark of Dombeya Rotundifolia Hochst. S.N. NDWIGAH*', G.N. THOITHI', J.W. MWANGI~ AND 1.0. KIBWAGE'. 'Department of Pharmaceutical Chemistry, School of Pharmacy, University of Nairobi,. P. 0.

  15. Maritime Security Concerns of the East African Community (EAC ...

    African Journals Online (AJOL)

    The maritime domain of the East African Community (EAC) is affected by a number of maritime security threats, including piracy, armed robbery against ships and an ongoing maritime border dispute between Kenya and Somalia. Neither the EAC nor its member States have long-term and holistic maritime security policies.

  16. 59 East and Central African Journal of Pharmaceutical Sciences Vol ...

    African Journals Online (AJOL)

    pharm-chem

    East and Central African Journal of Pharmaceutical Sciences. Vol. 16 (2013). There is a misconception that traditional medicine is unique to developing countries of Africa, Asia and. South America. This is certainly not true. Traditional medicine, often referred to as "alternative medicine", is widely used in developed countries ...

  17. East African Community Law : Institutional, Substantive and Comparative EU Aspects

    NARCIS (Netherlands)

    Ugirashebuja, E.; Ruhangisa, J.E.; Ottervanger, T.R.; Cuyvers, A.

    2017-01-01

    The East African Community (EAC) is a regional intergovernmental and supranational organization currently comprising the Republics of Burundi, Kenya, Rwanda, South Sudan, the United Republic of Tanzania, and the Republic of Uganda. Established in 2000, the EAC aims at widening and deepening

  18. Comparison of East African and Iran natural feeding condition based ...

    African Journals Online (AJOL)

    In this scientific work, we used soils from Zanzibar (Tansania region east African), Guilan (north of Iran), Tehran (center of Iran) and two type of soils from Zabol and Saravan regions (southeastern of Iran) in a condition simulated like atmospheric ones. The amounts of reduced Fe, Mn, Cu, Zn, pH, Ec, carbohydrate and lipid ...

  19. Looking forward to the East African Countries' Collaboration in ...

    African Journals Online (AJOL)

    of harmonizing nursing and midwifery education, practice and legislation. A study to ... opportunity for University Deans in the East African region to dialogue and examine possible areas .... essentials for a productive collaboration including; ... and 4 students graduated in mental health programs. ... such as e-learning.

  20. Primary breast sarcoma: case report | Hassan | East African Medical ...

    African Journals Online (AJOL)

    East African Medical Journal. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 81, No 7 (2004) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register · Download this PDF file. The PDF file you selected should ...

  1. Kaposis sarcoma in a Nairobi Hospital | Onyango | East African ...

    African Journals Online (AJOL)

    East African Medical Journal. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 81, No 3 (2004) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register · Download this PDF file. The PDF file you selected should ...

  2. Human Cryptosporidiosis: A Review | Ayuo | East African Medical ...

    African Journals Online (AJOL)

    East African Medical Journal. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 86, No 2 (2009) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register · Download this PDF file. The PDF file you selected should ...

  3. Editorial : Emerging issues of measles | Obimbo | East African ...

    African Journals Online (AJOL)

    East African Medical Journal. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 78, No 1 (2001) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register · Download this PDF file. The PDF file you selected should ...

  4. Task Shifting in HIV Clinics, Western Kenya | Kosgei | East African ...

    African Journals Online (AJOL)

    East African Medical Journal. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 87, No 7 (2010) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register · Download this PDF file. The PDF file you selected should ...

  5. Primary cerebral angitis of the central nervous | Das | East African ...

    African Journals Online (AJOL)

    Various medications like intravenous immunoglobulin, antibiotics, acyclovir, methyl prednisolone and management for raised intracranial pressure were instituted. She rapidly deteroriated and died on tenth hospital day. Only at autopsy was the diagnosis of primary angitis of central nervous system established. East African ...

  6. Scopus: Journal of East African Ornithology - Vol 32 (2012)

    African Journals Online (AJOL)

    Remarks concerning the East African coastal form of the Tropical Boubou Laniarius aethiopicus sublacteus (Cassin 1851), and its supposed black morph · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. DA Turner, BW Finch, ND Hunter, 47-49 ...

  7. East and Central African Journal of Pharmaceutical Sciences

    African Journals Online (AJOL)

    The East and Central African Journal of Pharmaceutical Sciences is dedicated to all aspects of Pharmaceutical Sciences research and is published in English. The scientific papers published in the Journal fall into three main categories: review papers, original research papers and short communications. Review papers in ...

  8. Agricultural Trade and Economic Growth in East African Community ...

    African Journals Online (AJOL)

    East African Community states, as many other states in the region, depend largely on agricultural activities to boost their economic growth and create employment. Up to 80 per cent of the populace depends on agriculture directly and indirectly for food, employment and income, while about 40 million people in EAC suffer ...

  9. Seasonal diet and prey preference of the African lion in a waterhole-driven semi-arid savanna.

    Science.gov (United States)

    Davidson, Zeke; Valeix, Marion; Van Kesteren, Freya; Loveridge, Andrew J; Hunt, Jane E; Murindagomo, Felix; Macdonald, David W

    2013-01-01

    Large carnivores inhabiting ecosystems with heterogeneously distributed environmental resources with strong seasonal variations frequently employ opportunistic foraging strategies, often typified by seasonal switches in diet. In semi-arid ecosystems, herbivore distribution is generally more homogeneous in the wet season, when surface water is abundant, than in the dry season when only permanent sources remain. Here, we investigate the seasonal contribution of the different herbivore species, prey preference and distribution of kills (i.e. feeding locations) of African lions in Hwange National Park, Zimbabwe, a semi-arid African savanna structured by artificial waterholes. We used data from 245 kills and 74 faecal samples. Buffalo consistently emerged as the most frequently utilised prey in all seasons by both male (56%) and female (33%) lions, contributing the most to lion dietary biomass. Jacobs' index also revealed that buffalo was the most intensively selected species throughout the year. For female lions, kudu and to a lesser extent the group "medium Bovidae" are the most important secondary prey. This study revealed seasonal patterns in secondary prey consumption by female lions partly based on prey ecology with browsers, such as giraffe and kudu, mainly consumed in the early dry season, and grazers, such as zebra and suids, contributing more to female diet in the late dry season. Further, it revealed the opportunistic hunting behaviour of lions for prey as diverse as elephants and mice, with elephants taken mostly as juveniles at the end of the dry season during droughts. Jacobs' index finally revealed a very strong preference for kills within 2 km from a waterhole for all prey species, except small antelopes, in all seasons. This suggested that surface-water resources form passive traps and contribute to the structuring of lion foraging behaviour.

  10. Seasonal diet and prey preference of the African lion in a waterhole-driven semi-arid savanna.

    Directory of Open Access Journals (Sweden)

    Zeke Davidson

    Full Text Available Large carnivores inhabiting ecosystems with heterogeneously distributed environmental resources with strong seasonal variations frequently employ opportunistic foraging strategies, often typified by seasonal switches in diet. In semi-arid ecosystems, herbivore distribution is generally more homogeneous in the wet season, when surface water is abundant, than in the dry season when only permanent sources remain. Here, we investigate the seasonal contribution of the different herbivore species, prey preference and distribution of kills (i.e. feeding locations of African lions in Hwange National Park, Zimbabwe, a semi-arid African savanna structured by artificial waterholes. We used data from 245 kills and 74 faecal samples. Buffalo consistently emerged as the most frequently utilised prey in all seasons by both male (56% and female (33% lions, contributing the most to lion dietary biomass. Jacobs' index also revealed that buffalo was the most intensively selected species throughout the year. For female lions, kudu and to a lesser extent the group "medium Bovidae" are the most important secondary prey. This study revealed seasonal patterns in secondary prey consumption by female lions partly based on prey ecology with browsers, such as giraffe and kudu, mainly consumed in the early dry season, and grazers, such as zebra and suids, contributing more to female diet in the late dry season. Further, it revealed the opportunistic hunting behaviour of lions for prey as diverse as elephants and mice, with elephants taken mostly as juveniles at the end of the dry season during droughts. Jacobs' index finally revealed a very strong preference for kills within 2 km from a waterhole for all prey species, except small antelopes, in all seasons. This suggested that surface-water resources form passive traps and contribute to the structuring of lion foraging behaviour.

  11. Large herbivore population performance and climate in a South African semi-arid savanna

    Directory of Open Access Journals (Sweden)

    Armin H. Seydack

    2012-02-01

    Interpretation according to a climate–vegetation response model suggested that acclimation of forage plants to increasing temperature had resulted in temperature-enhanced plant productivity, initially increasing food availability and supporting transient synchronous increases in population abundance of both blue wildebeest and zebra, and selective grazers. As acclimation of plants to concurrently rising minimum (nocturnal temperature (Tmin took effect, adjustments in metabolic functionality occurred involving accelerated growth activity at the cost of storage-based metabolism. Growth-linked nitrogen dilution and reduced carbon-nutrient quality of forage then resulted in phases of subsequently declining herbivore populations. Over the long term (1910–2010, progressive plant functionality shifts towards accelerated metabolic growth rather than storage priority occurred in response to Tmin rising faster than maximum temperature (Tmax, thereby cumulatively compromising the carbon-nutrient quality of forage, a key resource for selective grazers. The results of analyses thus revealed consistency between herbivore population trends and levels of forage quantity and quality congruent with expected plant metabolic responses to climate effects. Thus, according to the climate-vegetation response model, climate effects were implicated as the ultimate cause of large herbivore population performance in space and over time. Conservation implications: In its broadest sense, the objective of this study was to contribute towards the enhanced understanding of landscape-scale functioning of savanna systems with regard to the interplay between climate, vegetation and herbivore population dynamics.

  12. East and Central African Journal of Surgery

    African Journals Online (AJOL)

    health institutions. Thus many patients present with advanced malignancies when surgery for cure is impossible and only palliative care can be offered. Unfortunately many African countries lack both facilities and specialists in palliative care. Until recently palliative care was not even included in the curriculum for medical.

  13. East and Central African Journal of Surgery

    African Journals Online (AJOL)

    cough, diphtheria and measles. These no longer reach epidemic proportions in Africa as they did 30 years ago. But against a background of over- population, war and malnutrition, malaria and the diarrhoea1 diseases take an increasing toll of African children. In the cities, the diseases associated with affluence and gluttony ...

  14. Greenhouse gas exchange in West African savanna ecosystems - how important are emissions from termite mounds?

    Science.gov (United States)

    Brümmer, C.; Brüggemann, N.

    2012-04-01

    Savannas cover large areas of the Earth's surface and play an important role in global carbon and nitrogen cycling. In this study, we present the soil-atmosphere exchange of N2O, CH4, and CO2 during two field campaigns throughout the growing seasons 2005 and 2006 at a natural savanna site that was not subject to human disturbances except for annual burning, and four agricultural sites planted with sorghum (n=2), cotton and peanut in Burkina Faso. The annual N2O emission of the nature reserve site amounted to 0.52 kg N2O-N ha-1 yr-1 in 2005 and to 0.67 kg N2O-N ha-1 yr-1 in 2006, whereas the calculated average annual N2O release of the crop sites was only 0.19 and 0.20 kg N2O-N ha-1 yr-1 in 2005 and 2006, respectively. As a result of a temporal up-scaling approach, a lower bound of annual N2O release could be given for two fertilized sorghum plots, that is, 0.83 kg N2O-N ha-1 yr-1 for a highly fertilized plot and 0.44 kg N2O-N ha-1 yr-1 for a moderately fertilized plot. During the rainy season both CH4 uptake in the range of up to 20 μg CH4-C m-2 h-1 as well as CH4 emission up to 300 μg CH4-C m-2 h-1 were observed at the nature reserve site, which was on average a CH4 source of 87.4 and 30.8 μg CH4-C m-2 h-1 in 2005 and 2006, respectively. All crop sites were on average weak CH4 sinks without significant seasonal variation. Uptake rates ranged between 2.5 and 8.7 μg CH4-C m-2 h-1. Occasionally very low net CH4 emission was observed after heavy rainfall events. Mean annual CH4 rates could be estimated to 2.48 kg CH4-C ha-1 yr-1 and -0.68 kg CH4-C ha-1 yr-1 for the nature reserve site and the crop sites, respectively. Trace gas emissions from termite (Cubitermes fungifaber) mounds that were almost exclusively found at the nature reserve were one order of magnitude higher for N2O and CO2, and two orders of magnitude higher for CH4 than soil emissions of the respective trace gas. Termite N2O, CH4 and CO2 release at the nature reserve contributed only 3.2%, 8.1% and

  15. Recovery of rangelands : the functioning of soil seed banks in a semi-arid African savanna

    NARCIS (Netherlands)

    Tessema, Z.K.

    2011-01-01

    Rangelands in Africa provide important forage resources for herbivores; particularly perennial grasses provide grazing for domestic and wild herbivores. However, semi-arid African rangelands experience severe vegetation and soil degradation due to heavy grazing, causing negative impacts

  16. Decay Functions of Soil Moisture: Implications for Land Cover Controls on Actual Evapotranspiration During the Wet Season of a West-African Savanna

    Science.gov (United States)

    Bassiouni, M.; Ceperley, N. C.; Mande, T.; Parlange, M. B.

    2012-04-01

    The West-African savanna experiences extreme seasonal climate. The role of vegetation and the impact of agriculture on the regional hydrology of these areas are not well understood. A better understanding of such phenomena is crucial, as water resources are becoming unstable and populations dependent on rain-fed agriculture are more vulnerable. This study examines soil moisture dynamics during the 2010 rainy season in the Singou River Basin, Burkina Faso. Volumetric soil water content and meteorological data are collected from seven stations of a wireless sensor network. This network covers representative types of land cover in the watershed including riverbank, wetland, open savanna, agricultural parkland, and forested upland savanna. Vegetation was also surveyed throughout the season. Here, we present parameterizations and exploratory analysis of soil moisture decay functions at each station considered. Results are compared to the seasonal evolution of soil moisture storage, potential evapotranspiration and vegetation density. Preliminary results suggest these soil moisture measurements may be essential to understanding actual evapotranspiration and the hydrological influence of the types of land cover in the watershed over time. These findings contribute to improved modeling of the ecohydrological behavior of the Singou River Basin and up-scaling of the sensor network data for regional water management purposes as part of an integrated research and development project, Info4Dourou.

  17. Seismicity of the Earth 1900-2013 East African Rift

    Science.gov (United States)

    Hayes, Gavin P.; Jones, Eric S.; Stadler, Timothy J.; Barnhart, William D.; McNamara, Daniel E.; Benz, Harley M.; Furlong, Kevin P.; Villaseñor, Antonio; Hayes, Gavin P.; Jones, Eric S.; Stadler, Timothy J.; Barnhart, William D.; McNamara, Daniel E.; Benz, Harley M.; Furlong, Kevin P.; Villaseñor, Antonio

    2014-01-01

    The East African Rift system (EARS) is a 3,000-km-long Cenozoic age continental rift extending from the Afar triple junction, between the horn of Africa and the Middle East, to western Mozambique. Sectors of active extension occur from the Indian Ocean, west to Botswana and the Democratic Republic of the Congo (DRC). It is the only rift system in the world that is active on a continent-wide scale, providing geologists with a view of how continental rifts develop over time into oceanic spreading centers like the Mid-Atlantic Ridge.

  18. Methods to determine the impact of rainfall on fuels and burned area in southern African savannas

    CSIR Research Space (South Africa)

    Archibald, S

    2010-11-01

    Full Text Available /Aux fins d'examen seulement Southern African re regimes as revealed by remote sensing S. Archibald1;2;6, R.J. Scholes1;2, D.P. Roy3, G.Roberts4, L. Boschetti5 April 9, 2010 1CSIR, Ecosystems Processes and Dynamics, PO Box 395, Pretoria 0001, South... densities have di erent e ects on the number of res per km2 and360 14 For Review Purposes Only/Aux fins d'examen seulement on the size of individual res. The number of ignitions increases with human population361 density, (Figure 7A) but there is a...

  19. Hybridization in East African swarm-raiding army ants

    DEFF Research Database (Denmark)

    Kronauer, Daniel Jc; Peters, Marcell K; Schöning, Caspar

    2011-01-01

    Hybridization can have complex effects on evolutionary dynamics in ants because of the combination of haplodiploid sex-determination and eusociality. While hybrid non-reproductive workers have been found in a range of species, examples of gene-flow via hybrid queens and males are rare. We studied...... hybridization in East African army ants (Dorylus subgenus Anomma) using morphology, mitochondrial DNA sequences, and nuclear microsatellites....

  20. Greenhouse gas emissions from Savanna ( Miombo ) woodlands ...

    African Journals Online (AJOL)

    Natural vegetation represents an important sink for greenhouse gases (GHGs); however, there is relatively little information available on emissions from southern African savannas. The effects of clearing savanna woodlands for crop production on soil fluxes of N2O, CO2 and CH4 were studied on clay (Chromic luvisol) and ...

  1. Rapid Assessment of Key Structural Elements of Different Vegetation Types of West African Savannas in Burkina Faso

    Directory of Open Access Journals (Sweden)

    Qasim Mohammad

    2016-01-01

    Full Text Available Estimations of Leaf Area Index (LAI have recently gained attention due to the sensitivity to the effects of climate change and its impact on forest ecosystems. Hence, a study was conducted on the LAI estimation of four vegetation types: (i gallery forests, (ii woodland savannas, (iii tree savannas, and (iv shrub savannas, at two protected areas of Nazinga Game Ranch and Bontioli Nature Reserve, Burkina Faso. A relationship between LAI and Crown Diameter was also investigated at these two sites. Digital hemispherical photography was used for the LAI estimation. Crown diameters (CD were determined perpendicular to each other and averaged for each tree and shrub. Overall results revealed that LAI ranged from 0-1.33 and the CD was recorded in the range of 0.46-11.01 m. The gallery forests recorded the highest mean LAI 1.33 ± 0.32 as well as the highest mean CD 7.69 ± 1.90 m. The LAI for the vegetation types were at their lower ends as the study was conducted in summer season, higher values are therefore expected in the wet season, as a significant correlation between LAI and precipitation has been emphasized by various studies. Continuous LAI monitoring and studies on various growth parameters of different vegetation types at the study sites are recommended towards enhanced monitoring and an ecologically feasible forest- and savanna-use and management to maintain essential ecosystem functions and services.

  2. Habitat differences in dung beetle assemblages in an African savanna-forest ecotone: implications for secondary seed dispersal.

    Science.gov (United States)

    Kunz, Britta K; Krell, Frank-Thorsten

    2011-06-01

    The probability and pattern of secondary seed dispersal by dung beetles (Scarabaeinae) depend on their community structure and composition at the site of primary deposition, which, in turn, seem to be strongly determined by vegetation. Consequently, we expected pronounced differences in secondary seed dispersal between forest and savanna in the northern Ivory Coast, West Africa. We found 99 dung beetle species at experimentally exposed dung piles of the olive baboon (Papio anubis (Lesson, 1827)), an important primary seed disperser in West Africa. Seventy-six species belonged to the roller and tunneler guilds, which are relevant for secondary seed dispersal. Most species showed a clear habitat preference. Contrary to the Neotropics, species number and abundance were much higher in the savanna than in the forest. Rollers and tunnelers each accounted for approximately 50% of the individuals in the savanna, but in the forest rollers made up only 4%. Seeds deposited into the savanna by an omnivorous primary disperser generally have a higher overall probability of being more rapidly dispersed secondarily by dung beetles than seeds in the forest. Also, rollers disperse seeds over larger distances. In contrast to other studies, small rollers were active in dispersal of large seeds, which were seemingly mistaken for dung balls. Our results suggest that rollers can remove seeds from any plant dispersed in primate dung in this ecosystem. © 2011 ISZS, Blackwell Publishing and IOZ/CAS.

  3. Biomass and leaf-level gas exchange characteristics of three African savanna C4 grass species under optimum growth conditions

    NARCIS (Netherlands)

    Mantlana, K.B.; Veenendaal, E.M.; Arneth, A.; Grispen, V.; Bonyongo, C.M.; Heitkönig, I.M.A.; Lloyd, J.

    2009-01-01

    C4 savanna grass species, Digitaria eriantha, Eragrostis lehmanniana and Panicum repens, were grown under optimum growth conditions with the aim of characterizing their above- and below-ground biomass allocation and the response of their gas exchange to changes in light intensity, CO2 concentration

  4. Emerging landscape degradation trends in the East African Horn

    Science.gov (United States)

    Pricope, N. G.; Michaelsen, J.; Husak, G. J.; Funk, C. C.; Lopez-Carr, D.

    2012-12-01

    Increasing climate variability along with declining trends in rainfall represent major risk factors affecting food security in many regions of the world. We identify Africa-wide regions where significant rainfall decreases from 1979-2011 are coupled with significant human population density increases. The rangelands of the East African Horn remain one of the world's most food insecure regions with significantly increasing human populations predominantly dependent on pastoralist and agro-pastoralist livelihoods. Widespread vegetation degradation is occurring, adversely impacting fragile ecosystems and human livelihoods. Using MODIS land cover and normalized difference vegetation index (NDVI) data collected since 2000, we observe significant changes in vegetation patterns and productivity over the last decade across the East African Horn and demonstrate that these two products can be used concurrently at large spatial scales to monitor vegetation dynamics at decadal time scales. Results demonstrate that a near doubling of the population in pastoral regions is linked with hotspots of degradation in vegetation condition. The most significant land cover change and browning trends are observed in areas experiencing drying precipitation trends in addition to increasing population pressures. These findings have serious implications for current and future regional food security monitoring and forecasting and for mitigation and adaptation strategies in a region where population is expected to continue increasing against a backdrop of drying climate trends.Fig.1(a)Change in standardized precipitation index in Africa between 1979-2010 (b)Change in population density at continental scale using the GRUMPv1 1990 and 2000 and AfriPop 2010 population density datasets Fig.2 Land cover change trajectories based on 2001-2009 MOD12Q1 Land Cover product for the East African Horn overlaid over aggregated FEWS Net Livelihoods Zones.

  5. Rapid assessment and mapping of tree cover in southern African savanna woodlands using a new iPhone App and Landsat 8 imagery

    Science.gov (United States)

    Fuller, D. O.

    2016-12-01

    Tree cover is a key parameter in climate modeling. It strongly influences CO2 exchanges between the land surface and atmosphere and surface energy balance. We measured percent woody canopy cover (PWCC) in the savanna woodlands of eastern Zambia over a 10-day period in May 2016 using a new iPhone App (CanopyApp) and related these field measurements to Landsat 8 (L8) Band 4 (red) imagery acquired approximately the same time. We then used parameters from the band 4 digital numbers (DNs)-PWCC linear regression to derive a new map of PWCC for the entire L8 scene. Consistent with theory and previous empirical studies, we found that the relationship between L8 band 4 DNs- PWCC was negative and linear (r2 = 0.61, p reflectance was weaker (r2 = 0.46, p shadowing effects and other spatial inhomogeneities from variable soil and background reflectance. Our PWCC map agreed qualitatively with similar percent tree-cover maps based on Landsat level 1 products and past field studies in the area conducted using a hemispherical lens. Our results also compared favorably with other remote sensing studies that have used complex multivariate approaches to estimate tree cover, which suggests that use of a single L8 band 4 is sufficient to estimate PWCC when spectral contrast exists between the grass, soil and tree layers during the austral fall period in southern African savannas.

  6. Yellow fever, Asia and the East African slave trade.

    Science.gov (United States)

    Cathey, John T; Marr, John S

    2014-05-01

    Yellow fever is endemic in parts of sub-Saharan Africa and South America, yet its principal vectors--species of mosquito of the genus Aedes--are found throughout tropical and subtropical latitudes. Phylogenetic analyses indicate that yellow fever originated in Africa and that its spread to the New World coincided with the slave trade, but why yellow fever has never appeared in Asia remains a mystery. None of several previously proposed explanations for its absence there is considered satisfactory. We contrast the trans-Atlantic slave trade, and trade across the Sahara and to the Arabian Peninsula and Mesopotamia, with that to Far East and Southeast Asian ports before abolition of the African slave trade, and before the scientific community understood the transmission vector of yellow fever and the viral life cycle, and the need for shipboard mosquito control. We propose that these differences in slave trading had a primary role in the avoidance of yellow fever transmission into Asia in the centuries before the 20(th) century. The relatively small volume of the Black African slave trade between Africa and East and Southeast Asia has heretofore been largely ignored. Although focal epidemics may have occurred, the volume was insufficient to reach the threshold for endemicity.

  7. The biggest fish in the sea? Dynamic Kenyan labour migration in the East African community

    NARCIS (Netherlands)

    Ong'ayo, A.O.O.; Oucho, J.O.; Oucho, L.A.

    2013-01-01

    This study assesses the Kenyan policy and institutional framework concerning South–South labour migration with particular focus on the East African Community (EAC) countries. It focuses mainly on one particular policy instrument, the East African Community Common Market framework. The research

  8. Nocturnal behavior by a diurnal ape, the West African chimpanzee (Pan troglodytes verus), in a savanna environment at Fongoli, Senegal.

    Science.gov (United States)

    Pruetz, Jill D

    2018-02-08

    I report on the nocturnal behavior of Fongoli chimpanzees in a savanna mosaic during different seasons and lunar phases and test the hypothesis that hot daytime temperatures influence activity at night. I predicted that apes would be more active at night during periods of greater lunar illuminosity given diurnal primates' lack of visual specializations for low-light conditions and in dry season months when water scarcity exacerbated heat stress. I observed chimpanzees for 403 hrs on 40 nights between 2007 and 2013 and categorized their activity as social, movement, or vocalization. I scored their activity as occurring after moonrise or before moonset and considered the influence of moon phase (fuller versus darker phases) as well as season on chimpanzee nocturnal behavior in the analyses. Results indicate that apes were more active after moonrise or before moonset during fuller moon phases in the dry season but not the wet season. Most night-time activity involved movement (travel or forage), followed by social behavior, and long-distance vocal communication. Animals in highly seasonal habitats often exhibit thermoregulatory adaptations but, like other primates, chimpanzees lack physiological mechanisms to combat thermal stress. This study provides evidence that they may exhibit behaviors that allow them to avoid high temperatures in a savanna environment, such as feeding and socializing at night during the hottest time of year and in the brightest moon phases. The results support theories invoking thermal stress as a selective pressure for hominins in open environments where heat would constrain temporal foraging niches, and suggest an adaptability of sleeping patterns in response to external factors. © 2018 Wiley Periodicals, Inc.

  9. East African Journal of Sciences (2015) Volume 9 (1) 41-48 Effect of ...

    African Journals Online (AJOL)

    tosheba

    East African Journal of Sciences (2015). Volume 9 (1) 41-48 ... but no significant difference was observed amongst them. Queen .... used method of termite management in western. Ethiopia ..... Ethiopia. Working Document Series 68, ICRA,.

  10. East and Central African Journal of Surgery http://www.bioline.org.br ...

    African Journals Online (AJOL)

    Patrick

    East and Central African Journal of Surgery ... Investigations and intra-operative findings were suggestive of testicular torsion. We report this case because of its unusual ... The diagnosis is made mainly through clinical examination and signs.

  11. East and Central African Journal of Surgery Volume 15 Number 2 ...

    African Journals Online (AJOL)

    DELL

    East and central African Journal of Surgery. Page 122 ... curriculum by integrating the basic and clinical sciences focusing on organ system and featuring early .... 5. identify the different radiological and imaging investigations. 6. know how to ...

  12. East and Central African Journal of Surgery Volume 15 Number 2 ...

    African Journals Online (AJOL)

    DELL

    East and central African Journal of Surgery. Page 136 ... at school. Early presentation, immediate intervention and treatment can prevent grave .... Bank DE, Diaz L, Behrman DA, Delaney J, Bizzocco S. Tongue entrapment in an aluminum.

  13. Kinematics of the entire East African Rift from GPS velocities

    Science.gov (United States)

    Floyd, M.; King, R. W.

    2017-12-01

    Through a collaborative effort of the GeoPRISMS East Africa Rift GPS Working Group, we have collected and collated all of the publicly available continuous and survey-mode data for the entire rift system between 1994 and 2017 and processed these data as part of a larger velocity solution for Africa, Arabia and western Eurasia. We present here our velocity solution encompassing the major bounding plates and intervening terranes along the East African Rift from the Red Sea to the Malawi Rift and adjacent regions for GPS sites with data spans of at least 2.4 years, and north and east velocity uncertainties less than 1.5 mm/yr. To obtain realistic uncertainties for the velocity estimates, we attempted at each stage of the analysis to account for the character of the noise: During phase processing, we used an elevation-dependent weighting based on the phase residuals for each station; we then examined each position time series, removing outliers and reweighting appropriately to account for the white noise component of the errors; and e accounted for temporal correlations by estimating an equivalent random-walk magnitude for each continuous site and applying the median value (0.5 mm/√yr) to all survey-mode sites. We rigorously estimate relative rotation rates of Nubia, by choosing subset of well-determined sites such that the effective weights of western, northeastern and southern Africa were roughly equivalent, and Somalia, for which the estimate is dominated by three sites (MALI, RCMN, SEY1) whose uncertainties are a factor of 2-3 smaller than those of the other sites. For both plates, the weighted root-mean-square of the velocity residuals is 0.5 mm/yr. Our unified velocity solution provides a geodetic framework and constraints on the continental-scale kinematics of surface motions as well as more local effects both within and outside of the rift structures. Specific focus areas with denser coverage than previous fields include the Danakil block, the Afar Rift, the

  14. Model, Proxy and Isotopic Perspectives on the East African Humid Period

    Science.gov (United States)

    Tierney, Jessica E.; Lewis, Sophie C.; Cook, Benjamin I.; LeGrande, Allegra N.; Schmidt, Gavin A.

    2011-01-01

    Both North and East Africa experienced more humid conditions during the early and mid-Holocene epoch (11,000-5000yr BP; 11-5 ka) relative to today. The North African Humid Period has been a major focus of paleoclimatic study, and represents a response of the hydrological cycle to the increase in boreal summer insolation and associated ocean, atmosphere and land surface feedbacks. Meanwhile, the mechanisms that caused the coeval East African Humid Period are poorly understood. Here, we use results from isotopeenabled coupled climate modeling experiments to investigate the cause of the East African Humid Period. The modeling results are interpreted alongside proxy records of both water balance and the isotopic composition of rainfall. Our simulations show that the orbitally-induced increase in dry season precipitation and the subsequent reduction in precipitation seasonality can explain the East African Humid Period, and this scenario agrees well with regional lake level and pollen paleoclimate data. Changes in zonal moisture flux from both the Atlantic and Indian Ocean account for the simulated increase in precipitation from June through November. Isotopic paleoclimate data and simulated changes in moisture source demonstrate that the western East African Rift Valley in particular experienced more humid conditions due to the influx of Atlantic moisture and enhanced convergence along the Congo Air Boundary. Our study demonstrates that zonal changes in moisture advection are an important determinant of climate variability in the East African region.

  15. Estimating the Above-Ground Biomass in Miombo Savanna Woodlands (Mozambique, East Africa Using L-Band Synthetic Aperture Radar Data

    Directory of Open Access Journals (Sweden)

    Maria J. Vasconcelos

    2013-03-01

    Full Text Available The quantification of forest above-ground biomass (AGB is important for such broader applications as decision making, forest management, carbon (C stock change assessment and scientific applications, such as C cycle modeling. However, there is a great uncertainty related to the estimation of forest AGB, especially in the tropics. The main goal of this study was to test a combination of field data and Advanced Land Observing Satellite (ALOS Phased Array L-band Synthetic Aperture Radar (PALSAR backscatter intensity data to reduce the uncertainty in the estimation of forest AGB in the Miombo savanna woodlands of Mozambique (East Africa. A machine learning algorithm, based on bagging stochastic gradient boosting (BagSGB, was used to model forest AGB as a function of ALOS PALSAR Fine Beam Dual (FBD backscatter intensity metrics. The application of this method resulted in a coefficient of correlation (R between observed and predicted (10-fold cross-validation forest AGB values of 0.95 and a root mean square error of 5.03 Mg·ha−1. However, as a consequence of using bootstrap samples in combination with a cross validation procedure, some bias may have been introduced, and the reported cross validation statistics could be overoptimistic. Therefore and as a consequence of the BagSGB model, a measure of prediction variability (coefficient of variation on a pixel-by-pixel basis was also produced, with values ranging from 10 to 119% (mean = 25% across the study area. It provides additional and complementary information regarding the spatial distribution of the error resulting from the application of the fitted model to new observations.

  16. African Postal Heritage : Tanzania 1885-1920s : part I : German East Africa, 1885-1914

    NARCIS (Netherlands)

    Dietz, A.J.

    2016-01-01

    An earlier version of this African Postal Heritage Paper was published as African Studies Centre Leiden Working Paper 119 / 2015: "A postal history of the First World War in Africa and its aftermath - German colonies; III Deutsch Ostafrika / German East Africa", written by Ton Dietz.

  17. Ky'osimba Onaanya: Understanding Productivity of East African Highland Banana

    NARCIS (Netherlands)

    Taulya, G.

    2016-01-01

    Drought stress, potassium (K) and nitrogen (N) deficiencies are major constraints to East African highland banana (Musa spp. AAA-EA; hereafter referred to as ‘highland banana’), a primary staple food crop for over 30 million people in East Africa. This study explored the main and interactive effects

  18. Ky’osimba Onaanya: understanding productivity of East African Highland banana

    NARCIS (Netherlands)

    Taulya, G.

    2015-01-01

    Over 30 million people in East Africa depend on East African highland bananas for food and income. The bananas are grown with limited additions of nutrients and no irrigation, despite widespread poor soil fertility and regular dry seasons. This thesis describes the effect of increasing rainfall

  19. Competition between a Lawn-Forming Cynodon dactylon and a Tufted Grass Species Hyparrhenia hirta on a South-African Dystrophic Savanna.

    Science.gov (United States)

    Zwerts, J A; Prins, H H T; Bomhoff, D; Verhagen, I; Swart, J M; de Boer, W F

    2015-01-01

    South African savanna grasslands are often characterised by indigestible tufted grass species whereas lawn grasses are far more desirable in terms of herbivore sustenance. We aimed to investigate the role of nutrients and/or the disturbance (grazing, trampling) by herbivores on the formation of grazing lawns. We conducted a series of common garden experiments to test the effect of nutrients on interspecific competition between a typical lawn-forming grass species (Cynodon dactylon) and a species that is frequently found outside grazing lawns (Hyparrhenia hirta), and tested for the effect of herbivore disturbance in the form of trampling and clipping. We also performed a vegetation and herbivore survey to apply experimentally derived insights to field observations. Our results showed that interspecific competition was not affected by soil nutrient concentrations. C. dactylon did show much more resilience to disturbance than H. hirta, presumably due to the regenerative capacity of its rhizomes. Results from the field survey were in line with these findings, describing a correlation between herbivore pressure and C. dactylon abundance. We conclude that herbivore disturbance, and not soil nutrients, provide C. dactylon with a competitive advantage over H. hirta, due to vegetative regeneration from its rhizomes. This provides evidence for the importance of concentrated, high herbivore densities for the creation and maintenance of grazing lawns.

  20. Seasonal Variation and Ecosystem Dependence of Emission Factors for Selected Trace Gases and PM2.5 for Southern African Savanna Fires

    Science.gov (United States)

    Korontzi, S.; Ward, D. E.; Susott, R. A.; Yokelson, R. J.; Justice, C. O.; Hobbs, P. V.; Smithwick, E. A. H.; Hao, W. M.

    2003-01-01

    In this paper we present the first early dry season (early June-early August) emission factor measurements for carbon dioxide (CO2), carbon monoxide (CO), methane (Ca), nonmethane hydrocarbons (NMHC), and particulates with a diameter less than 2.5 microns (pM2.5) for southern African grassland and woodland fires. Seasonal emission factors for grassland fires correlate linearly with the proportion of green grass, used as a surrogate for the fuel moisture content, and are higher for products of incomplete combustion in the early part of the dry season compared with later in the dry season. Models of emission factors for NMHC and PM(sub 2.5) versus modified combustion efficiency (MCE) are statistically different in grassland compared with woodland ecosystems. We compare predictions based on the integration of emissions factors from this study, from the southern African Fire-Atmosphere Research Initiative 1992 (SAFARI-92), and from SAFARI-2000 with those based on the smaller set of ecosystem-specific emission factors to estimate the effects of using regional-average rather than ecosystem-specific emission factors. We also test the validity of using the SAFARI-92 models for emission factors versus MCE to predict the early dry season emission factors measured in this study. The comparison indicates that the largest discrepancies occur at the low end (0.907) and high end (0.972) of MCE values measured in this study. Finally, we combine our models of MCE versus proportion of green grass for grassland fires with emission factors versus MCE for selected oxygenated volatile organic compounds measured in the SAFARI-2000 campaign to derive the first seasonal emission factors for these compounds. The results of this study demonstrate that seasonal variations in savanna fire emissions are important and should be considered in modeling emissions at regional to continental scales.

  1. Breeding performance of the Grasshopper Buzzard (Butastur rufipennis) in a natural and a human-modified West African savanna

    NARCIS (Netherlands)

    Buij, R.; Kortekaas, K.; Krimpen, R.R.D.; Wijk, van H.J.; Zanden, S.; Iongh, de H.H.; Heitkonig, I.M.A.; Snoo, de G.R.; Komdeur, J.

    2013-01-01

    Few studies have examined raptor reproduction in response to land-use change in sub-Saharan Africa, hampering conservation efforts to address regional declines. To further our understanding of mechanisms underlying the dramatic declines of West African raptors, we examined the relationship between

  2. Impacts of 1.5 versus 2.0 °C on cereal yields in the West African Sudan Savanna

    Science.gov (United States)

    Faye, Babacar; Webber, Heidi; Naab, Jesse B.; MacCarthy, Dilys S.; Adam, Myriam; Ewert, Frank; Lamers, John P. A.; Schleussner, Carl-Friedrich; Ruane, Alex; Gessner, Ursula; Hoogenboom, Gerrit; Boote, Ken; Shelia, Vakhtang; Saeed, Fahad; Wisser, Dominik; Hadir, Sofia; Laux, Patrick; Gaiser, Thomas

    2018-03-01

    To reduce the risks of climate change, governments agreed in the Paris Agreement to limit global temperature rise to less than 2.0 °C above pre-industrial levels, with the ambition to keep warming to 1.5 °C. Charting appropriate mitigation responses requires information on the costs of mitigating versus associated damages for the two levels of warming. In this assessment, a critical consideration is the impact on crop yields and yield variability in regions currently challenged by food insecurity. The current study assessed impacts of 1.5 °C versus 2.0 °C on yields of maize, pearl millet and sorghum in the West African Sudan Savanna using two crop models that were calibrated with common varieties from experiments in the region with management reflecting a range of typical sowing windows. As sustainable intensification is promoted in the region for improving food security, simulations were conducted for both current fertilizer use and for an intensification case (fertility not limiting). With current fertilizer use, results indicated 2% units higher losses for maize and sorghum with 2.0 °C compared to 1.5 °C warming, with no change in millet yields for either scenario. In the intensification case, yield losses due to climate change were larger than with current fertilizer levels. However, despite the larger losses, yields were always two to three times higher with intensification, irrespective of the warming scenario. Though yield variability increased with intensification, there was no interaction with warming scenario. Risk and market analysis are needed to extend these results to understand implications for food security.

  3. Anorexia nervosa in Kenya | Njenga | East African Medical Journal

    African Journals Online (AJOL)

    Background: Anorexia nervosa is a rare disorder in Africans, inspite of posing a serious public health hazard in the West. Whereas it is possible that African psychiatrists lack the skills to diagnose the disorder, other possible explanations for its apparent rarity must be sought in view of emerging evidence, which suggests a ...

  4. Applying East Asian Media Diplomacy Models to African Media: A ...

    African Journals Online (AJOL)

    The last two decades have seen the extensive expansion of South African and Nigerian media on the African continent. However, while the link between media and diplomacy, and the role of media in visualising the state for foreign audiences have received a lot of scholarly attention internationally, relatively little work has ...

  5. Use of Machine Learning Techniques for Identification of Robust Teleconnections to East African Rainfall Variability

    Science.gov (United States)

    Roberts, J. Brent; Robertson, F. R.; Funk, C.

    2014-01-01

    Hidden Markov models can be used to investigate structure of subseasonal variability. East African short rain variability has connections to large-scale tropical variability. MJO - Intraseasonal variations connected with appearance of "wet" and "dry" states. ENSO/IOZM SST and circulation anomalies are apparent during years of anomalous residence time in the subseasonal "wet" state. Similar results found in previous studies, but we can interpret this with respect to variations of subseasonal wet and dry modes. Reveal underlying connections between MJO/IOZM/ENSO with respect to East African rainfall.

  6. Ky'osimba Onaanya: Understanding Productivity of East African Highland Banana

    OpenAIRE

    Taulya, G.

    2016-01-01

    Over 30 million people in East Africa depend on East African highland bananas for food and income. The bananas are grown with limited additions of nutrients and no irrigation, despite widespread poor soil fertility and regular dry seasons. This thesis describes the effect of increasing rainfall and application of potassium and nitrogen fertilizers on banana growth and yields. In areas that receive less than 1100 mm of rainfall per year, additional rainfall increases yields by 65%. Application...

  7. THE IDIOSYNCRASY OF EAST AFRICAN ENGLISH Maria Tsilimos ...

    African Journals Online (AJOL)

    maria tsilimos

    officer of the Consortium for Independent Education Providers in Sub-Saharan Africa, ... African English has to be studied systematically in order that its unique characteristics can be ..... the contextualisation of the event that is narrated. Also ...

  8. Household Density and Infant Care in an East African Society

    Science.gov (United States)

    Munroe, Ruth H.; Munroe, Robert L.

    1971-01-01

    A cross-cultural relationship between household density and infant indulgence was investigated among Logoli infants in East Africa. Findings were taken as supportive of the view that socialization practices are influenced by ecological variables. (Author/JB)

  9. Regional Integration: A Political Federation of the East African ...

    African Journals Online (AJOL)

    sulaiman.adebowale

    2006-06-13

    Jun 13, 2006 ... He suggested that the countries of the East Africa Community (EAC) together with .... tries engaged in free trade for local produce. This was .... First, he averred that economic integration is not enough because of political ...

  10. Is the Proposed East African Monetary Union an Optimal Currency Area? A Structural Vector Autoregression Analysis

    OpenAIRE

    Steven K. Buigut; Neven Valev

    2004-01-01

    The treaty of 1999 to revive the defunct East African Community (EAC) ratified by Kenya, Uganda, and Tanzania came into force on July 2000 with the objective of fostering a closer co-operation in political, economic, social, and cultural fields. To achieve this, an East Africa Customs Union protocol was signed in March 2004. A Common Market, a Monetary Union, and ultimately a Political Federation of East Africa states is planned. Though the question of a monetary union has been discussed in t...

  11. Signatures of selection for environmental adaptation and zebu × taurine hybrid fitness in East African shorthorn zebu

    Science.gov (United States)

    The East African Shorthorn Zebu (EASZ) cattle are ancient hybrid between Asian zebu × African taurine cattle preferred by local farmers due to their adaptability to the African environment. The genetic controls of these adaptabilities are not clearly understood yet. Here, we genotyped 92 EASZ sample...

  12. Insights into the management of large carnivores for profitable wildlife-based land uses in African savannas.

    Directory of Open Access Journals (Sweden)

    Paul J Funston

    Full Text Available Large African predators, especially lions (Panthera leo and leopards (Panthera pardus, are financially valuable for ecotourism and trophy hunting operations on land also utilized for the production of other wildlife species for the same purpose. Predation of ungulates used for trophy hunting can create conflict with landholders and trade off thus exists between the value of lions and leopards and their impact on ungulate populations. Therefore productionist and conservation trade-offs are complexly graded and difficult to resolve. We investigated this with a risk-benefit analysis on a large private wildlife production area in Zimbabwe. Our model showed that lions result in substantial financial costs through predation on wild ungulates that may not be offset by profits from hunting them, whereas the returns from trophy hunting of leopards are projected to exceed the costs due to leopard predation. In the absence of additional income derived from photo-tourism the number of lions may need to be managed to minimize their impact. Lions drive important ecological processes, but there is a need to balance ecological and financial imperatives on wildlife ranches, community wildlife lands and other categories of multiple use land used for wildlife production. This will ensure the competitiveness of wildlife based land uses relative to alternatives. Our findings may thus be limited to conservancies, community land-use areas and commercial game ranches, which are expansive in Africa, and should not necessarily applied to areas where biodiversity conservation is the primary objective, even if hunting is allowed there.

  13. Use and misuse of aspirin in rural Ethiopia | Duncan | East African ...

    African Journals Online (AJOL)

    East African Medical Journal. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 83, No 1 (2006) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register · Download this PDF file. The PDF file you selected should ...

  14. East African Journal of Public Health - Vol 7, No 1 (2010)

    African Journals Online (AJOL)

    East African Journal of Public Health. ... DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. E Mutabaruka, C Dochez, D Nshimirimana, A Meheus ... Prevalence of cigarette smoking and knowledge of its health implications among Nigerian soldiers · EMAIL FULL TEXT EMAIL FULL TEXT DOWNLOAD FULL TEXT ...

  15. Drought is a major yield loss factor for rainfed East African highland banana

    NARCIS (Netherlands)

    Asten, van P.; Asten-Fermont, van A.M.; Taulya, G.

    2011-01-01

    Although drought stress has been identified among the production constraints of East African highland bananas (Musa spp., AAA-EA genome), no quantitative data were available to support this assumption. This study uses data from three on-station fertilizer trials (5–6 cycles) in Central and Southwest

  16. Characteristics of soils in selected maize growing sites along altitudinal gradients in East African highlands

    Directory of Open Access Journals (Sweden)

    Elijah Njuguna

    2015-12-01

    Full Text Available Maize is the main staple crop in the East African Mountains. Understanding how the edaphic characteristics change along altitudinal gradients is important for maximizing maize production in East African Highlands, which are the key maize production areas in the region. This study evaluated and compared the levels of some macro and micro-elements (Al, Ca, Fe, K, Mg, Mn, Na and P and other soil parameters (pH, organic carbon content, soil texture [i.e. % Sand, % Clay and % Silt], cation exchange capacity [CEC], electric conductivity [EC], and water holding capacity [HC]. Soil samples were taken from maize plots along three altitudinal gradients in East African highlands (namely Machakos Hills, Taita Hills and Mount Kilimanjaro characterized by graded changes in climatic conditions. For all transects, pH, Ca, K and Mg decreased with the increase in altitude. In contrast, % Silt, organic carbon content, Al and water holding capacity (HC increased with increasing altitude. The research provides information on the status of the physical–chemical characteristics of soils along three altitudinal ranges of East African Highlands and includes data available for further research.

  17. Louse-borne relapsing fever among East African refugees in Europe.

    Science.gov (United States)

    Antinori, Spinello; Mediannikov, Oleg; Corbellino, Mario; Raoult, Didier

    2016-01-01

    Louse-borne relapsing fever a neglected and forgotten disease by western physicians has recently re-emerged among East African migrants seeking asylum in Europe. We review here the cases observed so far together with a critical reappraisal of several issues regarding clinical presentation, diagnosis and treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. African mutinies in the Netherlands East Indies : a nineteenth-century colonial paradox

    NARCIS (Netherlands)

    Kessel, van W.M.J.; Abbink, J.; Bruijn, de M.E.; Walraven, van K.

    2003-01-01

    Between 1831 and 1872, the Dutch government recruited 3,000 Africans from the Gold Coast and Ashanti (Ghana) for service in the colonial army in the Netherlands East Indies. The majority of them were ex-slaves but were promised that their conditions of service would be the same as those of

  19. Simulating sanitation and waste flows and their environmental impacts in East African urban centres

    NARCIS (Netherlands)

    Oyoo, R.

    2014-01-01

    Simulating Sanitation and Waste Flows and their Environmental Impacts in East African Urban Centres

    Abstract

    If improperly managed, urban waste flows can pose a significant threat to the quality of both the natural environment and public health.

  20. Tectonic inheritance and continental rift architecture: Numerical and analogue models of the East African Rift System.

    NARCIS (Netherlands)

    Corti, G.; van Wijk, J.W.; Cloetingh, S.A.P.L.; Morley, C.

    2007-01-01

    The western branch of the East African Rift is composed of an arcuate succession of elongate asymmetric basins, which differ in terms of interaction geometry, fault architecture and kinematics, and patterns of uplift/subsidence and erosion/sedimentation. The basins are located within Proterozoic

  1. Contrasted continental rifting via plume-craton interaction : Applications to Central East African Rift

    NARCIS (Netherlands)

    Koptev, Alexander; Burov, Evgueni; Calais, Eric; Leroy, Sylvie; Gerya, Taras; Guillou-Frottier, Laurent; Cloetingh, Sierd

    The East African Rift system (EARS) provides a unique system with the juxtaposition of two contrasting yet simultaneously formed rift branches, the eastern, magma-rich, and the western, magma-poor, on either sides of the old thick Tanzanian craton embedded in a younger lithosphere. Data on the

  2. East and Central African Journal of Surgery Volume 15 Number 2 ...

    African Journals Online (AJOL)

    DELL

    East and Central African Journal of Surgery Volume 15 Number 2. ... Makerere University,School of Biomedical sciences Department of Anatomy, P.O Box 7072, ..... should be borne in mind when locating the nerve for a regional block in the ...

  3. Evaluation of the LISEM soil erosion model in two catchments in the East African Highlands

    NARCIS (Netherlands)

    Hessel, R.; Bosch, van den R.; Vigiak, O.

    2006-01-01

    Under increasing population pressure, soil erosion has become a threat in the East African Highlands, and erosion modelling can be useful to quantify this threat. To test its applicability for this region, the LISEM soil erosion model was applied to two small catchments, one in the Usumbara

  4. Managing scalp defects in sub-Saharan Africa | Legbo | East African ...

    African Journals Online (AJOL)

    Conclusions: Management of scalp defects remains a major challenge in our environment. The importance of continuing education of colleagues and other health workers in peripheral health units on the importance of proper initial wound debridement and early referral cannot be overemphasised. East African Medical ...

  5. The role of households in solid waste management in East African capital cities

    NARCIS (Netherlands)

    Solomon, A.O.

    2011-01-01

    Solid Management is a concern in East African capital cities. The absence of managing solid waste is a serious problem. An ever bigger concern is the growing quantities of waste that are generatedat households level in informal settlements. In most cases proper safeguard measures are largely

  6. Social Realism in the African Novel: The South African and East ...

    African Journals Online (AJOL)

    Although the African novel arose from Europe, the African has used it to explore a different world view; a world where gods and men hold a place together in the affairs of men. But more importantly, the African novel has followed the peculiar history of colonization and decolonization. While the earlier novels depicted the ...

  7. Effects of anabolic and catabolic nutrients on woody plant encroachment after long-term experimental fertilization in a South African savanna.

    Directory of Open Access Journals (Sweden)

    Anthony J Mills

    Full Text Available The causes of the worldwide problem of encroachment of woody plants into grassy vegetation are elusive. The effects of soil nutrients on competition between herbaceous and woody plants in various landscapes are particularly poorly understood. A long-term experiment of 60 plots in a South African savanna, comprising annual applications of ammonium sulphate (146-1166 kg ha-1 yr-1 and superphosphate (233-466 kg ha-1 yr-1 over three decades, and subsequent passive protection over another three decades, during which indigenous trees encroached on different plots to extremely variable degrees, provided an opportunity to investigate relationships between soil properties and woody encroachment. All topsoils were analysed for pH, acidity, EC, water-dispersible clay, Na, Mg, K, Ca, P, S, C, N, NH4, NO3, B, Mn, Cu and Zn. Applications of ammonium sulphate (AS, but not superphosphate (SP, greatly constrained tree abundance relative to control plots. Differences between control plots and plots that had received maximal AS application were particularly marked (16.3 ± 5.7 versus 1.2 ± 0.8 trees per plot. Soil properties most affected by AS applications included pH (H2O (control to maximal AS application: 6.4 ± 0.1 to 5.1 ± 0.2, pH (KCl (5.5 ± 0.2 to 4.0 ± 0.1, acidity (0.7 ± 0.1 to 2.6 ± 0.3 cmol kg-1, acid saturation (8 ± 2 to 40 ± 5%, Mg (386 ± 25 to 143 ± 15 mg kg-1, Ca (1022 ± 180 to 322 ± 14 mg kg-1, Mn (314 ± 11 to 118 ± 9 mg kg-1, Cu (3.6 ± 0.3 to 2.3 ± 0.2 mg kg-1 and Zn (6.6 ± 0.4 to 3.7 ± 0.4 mg kg-1. Magnesium, B, Mn and Cu were identified using principal component analysis, boundary line analysis and Kruskal-Wallis rank sum tests as the nutrients most likely to be affecting tree abundance. The ratio Mn/Cu was most related to tree abundance across the experiment, supporting the hypothesis that competition between herbaceous and woody plants depends on the availability of anabolic relative to catabolic nutrients. These findings

  8. Maintainability in a manpower system | Owino | East African Journal ...

    African Journals Online (AJOL)

    : EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT · http://dx.doi.org/10.4314/eajosta.v1i1.39173 · AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors ...

  9. East African Medical Journal - Vol 83, No 9 (2006)

    African Journals Online (AJOL)

    An overview of health financing patterns and the way forward in the who african region · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. JM Kirigia, A Preker, G Carrin, C Mwikisa, AJ Diarra-Nama, S1-S28. http://dx.doi.org/10.4314/eamj.v83i9.9492 ...

  10. East African Medical Journal - Vol 87, No 8 (2010)

    African Journals Online (AJOL)

    Association of the ENPP1 rs997509 polymorphism with obesity in South African mixed ancestry learners · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. T Matsha, B Fanampe, Y Yako, S Hassan, M Hoffmann, L Van der Merwe, RT Erasmus ...

  11. Hantavirus strains in East Africa related to Western African hantaviruses

    Czech Academy of Sciences Publication Activity Database

    Těšíková, Jana; Bryjová, Anna; Bryja, Josef; Lavrenchenko, L. A.; Goüy de Bellocq, Joëlle

    2017-01-01

    Roč. 17, č. 4 (2017), s. 278-280 ISSN 1530-3667 R&D Projects: GA ČR GCP502/11/J070 Institutional support: RVO:68081766 Keywords : bats * East Africa * hantavirus * phylogeny * rodents Subject RIV: EE - Microbiology, Virology OBOR OECD: Infectious Diseases Impact factor: 2.045, year: 2016

  12. Journal of East African Natural History - Vol 89 (2000)

    African Journals Online (AJOL)

    10.2982/0012-8317(2000)89[73:ASOTSM]2.0.CO;2 · Status of the cheetah in Tanzania in the mid 1990's · EMAIL FULL TEXT EMAIL FULL TEXT DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. PM Gros, 85-100. Germination of important East ...

  13. East African refugees adapting to life in the UK

    Directory of Open Access Journals (Sweden)

    Samuel Bekalo

    2012-12-01

    Full Text Available This article reflects on the first-hand life experiences of refugees ofEast/Horn of Africa origin on arrival in the UK. The experiences – someof which could be seen as humorous or sad – may be informative andrelevant for other practitioners.

  14. Multilocus phylogeny of East African gerbils (Rodentia, Gerbilliscus) illuminates the history of the Somali-Masai savanna

    Czech Academy of Sciences Publication Activity Database

    Aghová, Tatiana; Šumbera, R.; Piálek, L.; Mikula, Ondřej; McDonough, M. M.; Lavrenchenko, L. A.; Meheretu, Y.; Mbau, J. S.; Bryja, Josef

    2017-01-01

    Roč. 44, č. 10 (2017), s. 2295-2307 ISSN 0305-0270 R&D Projects: GA ČR GAP506/10/0983; GA ČR GA15-20229S Institutional support: RVO:68081766 Keywords : biogeography * Gerbillinae * historical DNA * murid rodents * phylogeography * Plio-Pleistocene climate change * pyrosequencing * Rift Valley * species delimitation * tropical Africa Subject RIV: EG - Zoology OBOR OECD: Ecology Impact factor: 4.248, year: 2016

  15. Multilocus phylogeny of East African gerbils (Rodentia, Gerbilliscus) illuminates the history of the Somali-Masai savanna

    Czech Academy of Sciences Publication Activity Database

    Aghová, T.; Šumbera, R.; Piálek, L.; Mikula, Ondřej; McDonough, M. M.; Lavrenchenko, L. A.; Meheretu, Y.; Mbau, J. S.; Bryja, J.

    2017-01-01

    Roč. 44, č. 10 (2017), s. 2295-2307 ISSN 0305-0270 Institutional support: RVO:67985904 Keywords : biogeography * Gerbillinae * historical DNA * murid rodents * phylogeography Subject RIV: EA - Cell Biology OBOR OECD: Biology (theoretical, mathematical, thermal, cryobiology, biological rhythm), Evolutionary biology Impact factor: 4.248, year: 2016

  16. Raptors in changing West African savannas : the impact of anthropogenic land transformation on populations of Palearctic and Afrotropical raptors in northern Cameroon

    NARCIS (Netherlands)

    Buij, Ralph

    2013-01-01

    Raptors in West Africa’s savannas have strongly declined the past four decades and many species now survive only in a few pockets of intact habitat, mostly inside protected areas, while some species are on the brink of extinction. Little is known about the processes that sustain raptor populations

  17. Editorial : Emerging issues of measles | Obimbo | East African ...

    African Journals Online (AJOL)

    Metrics powered by PLOS ALM · http://dx.doi.org/10.4314/eamj.v78i1.9102 · AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors. OTHER RESOURCES... for Researchers · for Journals · for Authors · for Policy Makers · about Open Access · FAQ's · News · AJOL jobs · More about ...

  18. Forecasting The Onset Of The East African Rains

    Science.gov (United States)

    MacLeod, D.; Palmer, T.

    2017-12-01

    The timing of the rainy seasons is critical for East Africa, where many livelihoods depend on rain-fed agriculture. The exact onset date of the rains varies from year to year and a delayed start has significant implications for food security. Early warning of anomalous onset can help mitigate risks by informing farmer decisions on crop choice and timing of planting. Onset forecasts may also pre-warn governments and NGOs of upcoming need for financial support and humanitarian intervention. Here we assess the potential to forecast the onset of both the short and long rains over East Africa at subseasonal to seasonal timescales. Based on operational reforecasts from ECMWF, we will demonstrate skilful prediction of onset anomalies. An investigation to determine potential sources of this forecast skill will also be presented. This work has been carried out as part of the project ForPAc: "Towards forecast-based preparedness action".

  19. Geodynamics of the East African Rift System ∼30 Ma ago: A stress field model

    Science.gov (United States)

    Min, Ge; Hou, Guiting

    2018-06-01

    The East African Rift System (EARS) is thought to be an intra-continental ridge that meets the Red Sea and the Gulf of Aden at the Ethiopian Afar as the failed arm of the Afar triple junction. The geodynamics of EARS is still unclear even though several models have been proposed. One model proposes that the EARS developed in a local tensile stress field derived from far-field loads because of the pushing of oceanic ridges. Alternatively, some scientists suggest that the formation of the EARS can be explained by upwelling mantle plumes beneath the lithospheric weak zone (e.g., the Pan-African suture zone). In our study, a shell model is established to consider the Earth's spherical curvature, the lithospheric heterogeneity of the African continent, and the coupling between the mantle plumes and the mid-ocean ridge. The results are calculated via the finite element method using ANSYS software and fit the geological evidence well. To discuss the effects of the different rock mechanical parameters and the boundary conditions, four comparative models are established with different parameters or boundary conditions. Model I ignores the heterogeneity of the African continent, Model II ignores mid-ocean spreading, Model III ignores the upwelling mantle plumes, and Model IV ignores both the heterogeneity of the African continent and the upwelling mantle plumes. Compared to these models is the original model that shows the best-fit results; this model indicates that the coupling of the upwelling mantle plumes and the mid-ocean ridge spreading causes the initial lithospheric breakup in Afar and East Africa. The extension direction and the separation of the EARS around the Tanzanian craton are attributed to the heterogeneity of the East African basement.

  20. Attitudes, perceptions and behaviours towards HIV testing among African-American and East African immigrant women in Washington, DC: implications for targeted HIV testing promotion and communication strategies.

    Science.gov (United States)

    De Jesus, Maria; Carrete, Claudia; Maine, Cathleen; Nalls, Patricia

    2015-12-01

    The objective of the study was to examine and compare the HIV testing attitudes, perceptions and behaviours between African-American and East African immigrant women in the Washington, DC metropolitan area. Adopting an inductive, qualitative methodological approach, we conducted a total of 40 in-depth, semistructured interviews between October 2012 and March 2013. Qualitative thematic analysis was used to analyse the data. Overall, African-American women held more favourable views towards HIV testing than East African immigrant women. Very few East African immigrant women sought HIV testing intentionally. The majority of East African participants were tested inadvertently, while others tested for immigration-related or employment-related purposes. There were many barriers that impede women from seeking an HIV test including negative assumptions (eg, "Getting an HIV test implies that I am HIV positive"), negative emotions (eg, "Fear of being diagnosed with HIV and what this will mean for me") and potential negative reactions from partner or others (eg, "Getting an HIV test can signal distrust, disrespect, or infidelity"). There were nuances in how each group articulated some of these barriers and East African women expressed unique concerns that originated from experiences in their home countries. The study shed light into the complexity of factors that constrain women from presenting themselves voluntarily for an HIV test and highlighted the nuances between African-American and East African perceptions. Implications of findings for effective targeted HIV screening promotion and communication strategies among these groups of women are discussed. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  1. A new brachypterous scarab species, Orphnus longicornis (Coleoptera: Scarabaeidae: Orphninae), from the East African Rift.

    Science.gov (United States)

    Frolov, Andrey; Akhmetova, Lilia

    2015-11-05

    The Afrotropical Region is the center of the diversity of the scarab beetle genus Orphnus MacLeay, 1819 (Coleoptera: Scarabaeidae: Orphninae), with 94 species occurring from Sahel in the north to Little Karoo in the south (Paulian, 1948; Petrovitz, 1971; Frolov, 2008). The East African Rift is one of the richest regions of the Afrotropics housing more than 20 species of Orphnus (Paulian, 1948; Frolov, 2013), most of which are endemic to this region. Yet the scarab beetle fauna of the East African Rift, and especially the Eastern Arc Mountains, is still inadequately studied. Examination of the material housed in the Museum of Natural History of Humboldt-Universität, Berlin, Germany (ZMHUB), revealed a series of brachypterous Orphnus beetles belonging to an undescribed species. The new species is described and illustrated below.

  2. East African wetland-catchment data base for sustainable wetland management

    Science.gov (United States)

    Leemhuis, Constanze; Amler, Esther; Diekkrüger, Bernd; Gabiri, Geofrey; Näschen, Kristian

    2016-10-01

    Wetlands cover an area of approx. 18 Mio ha in the East African countries of Kenya, Rwanda, Uganda and Tanzania, with still a relative small share being used for food production. Current upland agricultural use intensification in these countries due to demographic growth, climate change and globalization effects are leading to an over-exploitation of the resource base, followed by an intensification of agricultural wetland use. We aim on translating, transferring and upscaling knowledge on experimental test-site wetland properties, small-scale hydrological processes, and water related ecosystem services under different types of management from local to national scale. This information gained at the experimental wetland/catchment scale will be embedded as reference data within an East African wetland-catchment data base including catchment physical properties and a regional wetland inventory serving as a base for policy advice and the development of sustainable wetland management strategies.

  3. East African wetland-catchment data base for sustainable wetland management

    Directory of Open Access Journals (Sweden)

    C. Leemhuis

    2016-10-01

    Full Text Available Wetlands cover an area of approx. 18 Mio ha in the East African countries of Kenya, Rwanda, Uganda and Tanzania, with still a relative small share being used for food production. Current upland agricultural use intensification in these countries due to demographic growth, climate change and globalization effects are leading to an over-exploitation of the resource base, followed by an intensification of agricultural wetland use. We aim on translating, transferring and upscaling knowledge on experimental test-site wetland properties, small-scale hydrological processes, and water related ecosystem services under different types of management from local to national scale. This information gained at the experimental wetland/catchment scale will be embedded as reference data within an East African wetland-catchment data base including catchment physical properties and a regional wetland inventory serving as a base for policy advice and the development of sustainable wetland management strategies.

  4. Estimates of interhemispheric transport of radioactive debris by the east African low-level jet stream

    International Nuclear Information System (INIS)

    Rangarajan, C.; Eapen, C.D.

    1981-01-01

    The movement of air masses across the equator by way of the east African low-level jet stream has been studied using fission products from the French nuclear tests of the South Pacific as tracers. The studies show that the transit time of air masses from Malagasy to India is 3--6 days and about 75% of the air mass on the west coast of India is from the southern hemisphere

  5. Immigrant Entrepreneurship in United Arab Emirates: An exploratory study on East African Asian Immigrant Businesses

    OpenAIRE

    Khakoo, Mohamed Hussein Turabali

    2008-01-01

    Immigrant entrepreneurship has always existed and has developed remarkably. It is related to migration flows over time and has brought increasing attention from researchers and management practitioners in recent years. The research sets out to investigate the process by which immigrants enter into entrepreneurship. The idea of starting a small business and the internationalization strategies they follow. A homogeneous ethnic minority is researched upon, the East African Asians who had migrate...

  6. Alienation and Revolutionary Vision in East African Post-Colonial Dramatic Literature

    OpenAIRE

    Fashina, Nelson O.

    2009-01-01

    This paper is a trans-disciplinary inquiry into the principles of alienation and revolutionary ethos in two East African plays of postcolonial society. It engages literary-textual exegesis and sociological theories to unravel the multi-dimensional forms of alienation as an interrogation of contemporary postcolonial history. The writers, though somewhat in throes and dilemma of exilic consciousness, ‘commodify’ and appropriate the literary enterprise as weapon of active physical revolt and tex...

  7. Managing invasions at the cost of native habitat? An experimental test of the impact of fire on the invasion of Chromolaena odorata in a South African savanna

    OpenAIRE

    te Beest, Mariska; Cromsigt, Joris P. G. M.; Ngobese, Johan; Olff, Han

    2012-01-01

    Successfully managing invasive plants in natural systems is extremely difficult. Recently however, progress has been made with an approach focused on changing ecosystem processes through the disturbance regime. We performed a large-scale (3 ha) full-factorial field experiment in densely invaded woodland in Hluhluwe-iMfolozi Park, a savanna reserve in South Africa, to study the effect of fire on the control of the pan-tropical invasive exotic shrub Chromolaena odorata in combination with the c...

  8. Ideological trends in initial teacher education curricula: the case of East African universities

    Directory of Open Access Journals (Sweden)

    Proscovia Namubiru Ssentamu

    2014-12-01

    Full Text Available This paper reviews the ideological trends in initial teacher education curricula in East African universities during the post-independent and contemporary times. From the mid-1960s and mid-1980s, initial teacher education curricula were integrated and harmonised with support from the East African Community whose efforts were coordinated by the Inter-University Council for East Africa. With the breakup of the Community in 1977, each independent state pursued its own educational strategy. However, underfunding of the public sector by governments, introduction of market-friendly reforms under the World Bank Structural Adjustment Programme in 1987 and the de-regularisation policies led to the liberalisation of public services, including education. Liberalisation affected among others, the quality of the initial teacher education curricula. Consequently, national councils and commissions for higher education were established to control standards in higher education, and the Inter-University Council for East Africa was revived to standardise and harmonise educational standards at regional level. The review shows that over the past five decades, the structure and organisation of initial teacher education curricula has continuously adjusted itself and been adjusted to a hybrid culture blending classical humanism, utilitarianism, social re-constructionism, market and global ideologies. Comparable ideological inclinations at socio-economic and political levels have influenced this trend in the region. The paper highlights the implications of such trends on the future of initial teacher education in the region.

  9. East-African Social Sciences and Humanities Publishing: A Handmade Bibliometrics Approach

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, N

    2016-07-01

    For Eastern Africa, very little information about the SSH knowledge production can be found from a European perspective. Adequate indicators like information-rich bibliographic databases that cover East-Africa-based journals and book publishers are lacking. This research in progress explores their indexing situation in detail, their development, which is closely connected to political history, their (non-)usage, and affiliations as well as careerstages of their authors. Furthermore, it also pays attention to East-Africa-based SSH researchers who use other publication venues. Any bibliometric analysis in this field needs to rely on manual data collection, otherwise it would be heavily biased. This study lays out the foundation for citation analyses, qualitative research on the publications' content and the self-description of East-African scholars against the background of an academic environment that is often described as “international”. (Author)

  10. Post-Pan-African tectonic evolution of South Malawi in relation to the Karroo and recent East African rift systems

    Science.gov (United States)

    Castaing, C.

    1991-05-01

    Structural studies conducted in the Lengwe and Mwabvi Karroo basins and in the basement in South Malawi, using regional maps and published data extended to cover Southeast Africa, serve to propose a series of geodynamic reconstructions which reveal the persistence of an extensional tectonic regime, the minimum stress σ3 of which has varied through time. The period of Karroo rifting and the tholeiitic and alkaline magmatism which terminated it, were controlled by NW-SE extension, which resulted in the creation of roughly NE-SW troughs articulated by the Tanganyika-Malawi and Zambesi pre-transform systems. These were NW-SE sinistral-slip systems with directions of movement dipping slightly to the Southeast, which enabled the Mwanza fault to play an important role in the evolution of the Karroo basins of the Shire Valley. The Cretaceous was a transition period between the Karroo rifting and the formation of the Recent East African Rift System. Extension was NE-SW, with some evidence for a local compressional episode in the Lengwe basin. Beginning in the Cenozoic, the extension once more became NW-SE and controlled the evolution in transtension of the Recent East African Rift System. This history highlights the major role of transverse faults systems dominated by strike-slip motion in the evolution and perpetuation of the continental rift systems. These faults are of a greater geological persistence than the normal faults bounding the grabens, especially when they are located on major basement anisotropies.

  11. Correlates of complete childhood vaccination in East African countries.

    Directory of Open Access Journals (Sweden)

    Maureen E Canavan

    Full Text Available BACKGROUND: Despite the benefits of childhood vaccinations, vaccination rates in low-income countries (LICs vary widely. Increasing coverage of vaccines to 90% in the poorest countries over the next 10 years has been estimated to prevent 426 million cases of illness and avert nearly 6.4 million childhood deaths worldwide. Consequently, we sought to provide a comprehensive examination of contemporary vaccination patterns in East Africa and to identify common and country-specific barriers to complete childhood vaccination. METHODS: Using data from the Demographic and Health Surveys (DHS for Burundi, Ethiopia, Kenya, Rwanda, Tanzania, and Uganda, we looked at the prevalence of complete vaccination for polio, measles, Bacillus Calmette-Guérin (BCG and DTwPHibHep (DTP as recommended by the WHO among children ages 12 to 23 months. We conducted multivariable logistic regression within each country to estimate associations between complete vaccination status and health care access and sociodemographic variables using backwards stepwise regression. RESULTS: Vaccination varied significantly by country. In all countries, the majority of children received at least one dose of a WHO recommended vaccine; however, in Ethiopia, Tanzania, and Uganda less than 50% of children received a complete schedule of recommended vaccines. Being delivered in a public or private institution compared with being delivered at home was associated with increased odds of complete vaccination status. Sociodemographic covariates were not consistently associated with complete vaccination status across countries. CONCLUSIONS: Although no consistent set of predictors accounted for complete vaccination status, we observed differences based on region and the location of delivery. These differences point to the need to examine the historical, political, and economic context of each country in order to maximize vaccination coverage. Vaccination against these childhood diseases is a

  12. Assessment of Aboveground Woody Biomass Dynamics Using Terrestrial Laser Scanner and L-Band ALOS PALSAR Data in South African Savanna

    Directory of Open Access Journals (Sweden)

    Victor Onyango Odipo

    2016-11-01

    Full Text Available The use of optical remote sensing data for savanna vegetation structure mapping is hindered by sparse and heterogeneous distribution of vegetation canopy, leading to near-similar spectral signatures among lifeforms. An additional challenge to optical sensors is the high cloud cover and unpredictable weather conditions. Longwave microwave data, with its low sensitivity to clouds addresses some of these problems, but many space borne studies are still limited by low quality structural reference data. Terrestrial laser scanning (TLS derived canopy cover and height metrics can improve aboveground biomass (AGB prediction at both plot and landscape level. To date, few studies have explored the strength of TLS for vegetation structural mapping, and particularly few focusing on savannas. In this study, we evaluate the potential of high resolution TLS-derived canopy cover and height metrics to estimate plot-level aboveground biomass, and to extrapolate to a landscape-wide biomass estimation using multi-temporal L-band Synthetic Aperture Radar (SAR within a 9 km2 area savanna in Kruger National Park (KNP. We inventoried 42 field plots in the wet season and computed AGB for each plot using site-specific allometry. Canopy cover, canopy height, and their product were regressed with plot-level AGB over the TLS-footprint, while SAR backscatter was used to model dry season biomass for the years 2007, 2008, 2009, and 2010 for the study area. The results from model validation showed a significant linear relationship between TLS-derived predictors with field biomass, p < 0.05 and adjusted R2 ranging between 0.56 for SAR to 0.93 for the TLS-derived canopy cover and height. Log-transformed AGB yielded lower errors with TLS metrics compared with non-transformed AGB. An assessment of the backscatter based on root mean square error (RMSE showed better AGB prediction with cross-polarized (RMSE = 6.6 t/ha as opposed to co-polarized data (RMSE = 6.7 t/ha, attributed to

  13. Relapsing fever causative agent in Southern Iran is a closely related species to East African borreliae.

    Science.gov (United States)

    Naddaf, Saied Reza; Ghazinezhad, Behnaz; Kazemirad, Elham; Cutler, Sally Jane

    2017-10-01

    We obtained two blood samples from relapsing fever patients residing in Jask County, Hormozgan Province, southern Iran in 2013. Sequencing of a partial fragment of glpQ from two samples, and further characterization of one of them by analyzing flaB gene, and 16S-23S spacer (IGS) revealed the greatest sequence identity with East African borreliae, Borrelia recurrentis, and Borrelia duttonii, and Borrelia microti from Iran. Phylogenetic analyses of glpQ, flaB, and concatenated sequences (glpQ, flab, and IGS) clustered these sequences amongst East African Relapsing fever borreliae and B. microti from Iran. However, the more discriminatory IGS disclosed a unique 8-bp signature (CAGCCTAA) separating these from B. microti and indeed other relapsing fever borreliae. In southern Iran, relapsing fever cases are mostly from localities in which O. erraticus ticks, the notorious vector of B. microti, prevail. There are chances that this argasid tick serves as a host and vector of several closely related species or ecotypes including the one we identified in the present study. The distribution of this Borrelia species remains to be elucidated, but it is assumed to be endemic to lowland areas of the Hormozgan Province, as well as Sistan va Baluchistan in the southeast and South Khorasan (in Persian: Khorasan-e Jonobi) in the east of Iran. Copyright © 2017 Elsevier GmbH. All rights reserved.

  14. Compilation of an informative microsatellite set for genetic characterisation of East African finger millet (Eleusine coracana

    Directory of Open Access Journals (Sweden)

    Santie M. De Villiers

    2015-03-01

    Discussion: Five individual samples from an accession captured the largest number of alleles per locus compared to the four different bulked sampling strategies but this difference was not significant. The identified set comprised 20 markers: UGEP24, UGEP53, UGEP84, UGEP27, UGEP98, UGEP95, UGEP64, UGEP33, UGEP67, UGEP106, UGEP110, UGEP57, UGEP96, UGEP66, UGEP46, UGEP79, UGEP20, UGEP12, UGEP73 and UGEP5 and was since used to assess East African finger millet genetic diversity in two separate studies.

  15. THE ORIGINS OF THE SOUTHERN AFRICAN MAMMAL FAUNA ...

    African Journals Online (AJOL)

    Southern Africa can be geographically subdivided into different biotic zones, differing from .... The greater part of the southern African mammal fauna consists of savanna .... spread into southern Africa by way of the Savanna biotic zone.

  16. Simultaneous determination of seven informative Y chromosome SNPs to differentiate East Asian, European, and African populations.

    Science.gov (United States)

    Muro, Tomonori; Iida, Reiko; Fujihara, Junko; Yasuda, Toshihiro; Watanabe, Yukina; Imamura, Shinji; Nakamura, Hiroaki; Kimura-Kataoka, Kaori; Yuasa, Isao; Toga, Tomoko; Takeshita, Haruo

    2011-05-01

    Identification of the population origin of an individual is very useful for crime investigators who need to narrow down a suspect based on specimens left at a crime scene. Single nucleotide polymorphisms of the Y chromosome (Y-SNPs) are a class of markers of interest to forensic investigators because many of the markers indicate regional specificity, thus providing useful information about the geographic origin of a subject. We selected seven informative Y-SNPs (M168, M130, JST021355, M96, P126, P196, and P234) to differentiate the three major population groups (East Asian, European, and African) and used them to develop forensic application. SNP genotyping was carried out by multiplex PCR reaction and multiplex single base extension (MSBE) reaction followed by capillary electrophoresis of extension products. This method can be used to assign a haplogroup from both degraded male DNA samples and DNA samples containing a mixture of female and male DNA through PCR primers that generate small amplicons (less than about 150 bp) and are highly specific for targets on the Y chromosome. The allelic state of each marker was definitively determined from a total of 791 males from the three major population groups. As expected, samples from the three major population groups showed Y-haplogroups common in the region of provenance: Y haplogroups C, D, and O for East Asians; IJ and R1 for Europeans; and AB and E for Africans. Published by Elsevier Ireland Ltd.

  17. Field Plot Techniques for Black Sigatoka Evaluation in East African Highland Bananas

    Directory of Open Access Journals (Sweden)

    Okoro, JU.

    1997-01-01

    Full Text Available Number of plants per experimental unit and number of replications for the efficient and precise assessment of black sigatoka leaf spot disease caused by Mycosphaerella fijiensis in East African Highland bananas were determined. Two representative cultivars were used. Host response to black sigatoka infection was measured by recording the youngest leaf with necrotic spots. The number of plants per experimental unit was determined, using the methods of maximum curvature and comparison of variances, while the number of replications was estimated by Hatheway's method. The optimum experimental plot size was 3 plants (18 m2 for the beer banana cultivar 'Igitsiri', and 30 plants (180 m2 for the cooking banana cultivar 'Igisahira Gisanzwe', using the comparison of variances method. However, the optimum plot size was 15 plants (90 m2 for both cultivars using the method of maximum curvature. The latter statistical method was preferred because of the low precision of the estimates in the former method. Unreplicated trials with plots of 15 plants could be adequate to assess black sigatoka response in East African bananas if uniform disease pressure exists.

  18. Post-collisional magmatism in the central East African Orogen: The Maevarano Suite of north Madagascar

    Science.gov (United States)

    Goodenough, K.M.; Thomas, Ronald J.; De Waele, B.; Key, R.M.; Schofield, D.I.; Bauer, W.; Tucker, R.D.; Rafahatelo, J.-M.; Rabarimanana, M.; Ralison, A.V.; Randriamananjara, T.

    2010-01-01

    Late tectonic, post-collisional granite suites are a feature of many parts of the Late Neoproterozoic to Cambrian East African Orogen (EAO), where they are generally attributed to late extensional collapse of the orogen, accompanied by high heat flow and asthenospheric uprise. The Maevarano Suite comprises voluminous plutons which were emplaced in some of the tectonostratigraphic terranes of northern Madagascar, in the central part of the EAO, following collision and assembly during a major orogeny at ca. 550 Ma. The suite comprises three main magmatic phases: a minor early phase of foliated gabbros, quartz diorites, and granodiorites; a main phase of large batholiths of porphyritic granitoids and charnockites; and a late phase of small-scale plutons and sheets of monzonite, syenite, leucogranite and microgranite. The main phase intrusions tend to be massive, but with variably foliated margins. New U-Pb SHRIMP zircon data show that the whole suite was emplaced between ca. 537 and 522 Ma. Geochemically, all the rocks of the suite are enriched in the LILE, especially K, and the LREE, but are relatively depleted in Nb, Ta and the HREE. These characteristics are typical of post-collisional granitoids in the EAO and many other orogenic belts. It is proposed that the Maevarano Suite magmas were derived by melting of sub-continental lithospheric mantle that had been enriched in the LILE during earlier subduction events. The melting occurred during lithospheric delamination, which was associated with extensional collapse of the East African Orogen. ?? 2009 Natural Environment Research Council.

  19. Phylogenetic relationships among East African haplochromine fish as revealed by short interspersed elements (SINEs).

    Science.gov (United States)

    Terai, Yohey; Takezaki, Naoko; Mayer, Werner E; Tichy, Herbert; Takahata, Naoyuki; Klein, Jan; Okada, Norihiro

    2004-01-01

    Genomic DNA libraries were prepared from two endemic species of Lake Victoria haplochromine (cichlid) fish and used to isolate and characterize a set of short interspersed elements (SINEs). The distribution and sequences of the SINEs were used to infer phylogenetic relationships among East African haplochromines. The SINE-based classification divides the fish into four groups, which, in order of their divergence from a stem lineage, are the endemic Lake Tanganyika flock (group 1); fish of the nonendemic, monotypic, widely distributed genus Astatoreochromis (group 2); the endemic Lake Malawi flock (group 3); and group 4, which contains fish from widely dispersed East African localities including Lakes Victoria, Edward, George, Albert, and Rukwa, as well as many rivers. The group 4 haplochromines are characterized by a subset of polymorphic SINEs, each of which is present in some individuals and absent in others of the same population at a given locality, the same morphologically defined species, and the same mtDNA-defined haplogroup. SINE-defined group 4 contains six of the seven previously described mtDNA haplogroups. One of the polymorphic SINEs appears to be fixed in the endemic Lake Victoria flock; four others display the presence-or-absence polymorphism within the species of this flock. These findings have implications for the origin of Lake Victoria cichlids and for their founding population sizes.

  20. Middle East and North African Health Informatics Association (MENAHIA): Building Sustainable Collaboration.

    Science.gov (United States)

    Al-Shorbaji, Najeeb; Househ, Mowafa; Taweel, Adel; Alanizi, Abdullah; Mohammed, Bennani Othmani; Abaza, Haitham; Bawadi, Hala; Rasuly, Hamayon; Alyafei, Khalid; Fernandez-Luque, Luis; Shouman, Mohamed; El-Hassan, Osama; Hussein, Rada; Alshammari, Riyad; Mandil, Salah; Shouman, Sarah; Taheri, Shahrad; Emara, Tamer; Dalhem, Wasmiya; Al-Hamdan, Zaid; Serhier, Zineb

    2018-04-22

    There has been a growing interest in Health Informatics applications, research, and education within the Middle East and North African Region over the past twenty years. People of this region share similar cultural and religious values, primarily speak the Arabic language, and have similar health care related issues, which are in dire need of being addressed. Health Informatics efforts, organizations, and initiatives within the region have been largely under-represented within, but not ignored by, the International Medical Informatics Association (IMIA). Attempts to create bonds and collaboration between the different organizations of the region have remained scattered, and often, resulted in failure despite the fact that the need for a united health informatics collaborative within the region has never been more crucial than today. During the 2017 MEDINFO, held in Hangzhou, China, a new organization, the Middle East and North African Health Informatics Association (MENAHIA) was conceived as a regional non-governmental organization to promote and facilitate health informatics uptake within the region endorsing health informatics research and educational initiatives of the 22 countries represented within the region. This paper provides an overview of the collaboration and efforts to date in forming MENAHIA and displays the variety of initiatives that are already occurring within the MENAHIA region, which MENAHIA will help, endorse, support, share, and improve within the international forum of health informatics. Georg Thieme Verlag KG Stuttgart.

  1. Influence of Mascarene High and Indian Ocean dipole on East African extreme weather events

    Directory of Open Access Journals (Sweden)

    Ogwang Bob Alex

    2015-01-01

    Full Text Available Extreme weather and climate events such as floods and droughts are common in East Africa, causing huge socio-economic losses. This study links the east African October-December (OND rainfall, Indian Ocean Dipole (IOD and Mascarene High (MH.Correlation analysis is applied to quantify the relationship between the index of IOD (Dipole Mode Index (DMI and OND rainfall. Results show that there exists a significant correlation between OND rainfall and DMI, with a correlation coefficient of 0.6. During dry years, MH is observed to intensify and align itself in the southeast-northwest orientation, stretching up to the continent, which in turn inhibits the influx of moisture from Indian Ocean into East Africa. During wet years, MH weakens, shifts to the east and aligns itself in the zonal orientation. Moisture from Indian Ocean is freely transported into east Africa during wet years. Analysis of the drought and flood years with respect to the different variables including wind, velocity potential and divergence/ convergence revealed that the drought (flood years were characterized by divergence (convergence in the lower troposphere and convergence (divergence at the upper level, implying sinking (rising motion, especially over the western Indian Ocean and the study area. Convergence at low level gives rise to vertical stretching, whereas divergence results in vertical shrinking, which suppresses convection due to subsidence. Positive IOD (Negative IOD event results into flood (drought in the region. The evolution of these phenomena can thus be keenly observed for utilization in the update of seasonal forecasts.

  2. Transformation of a savanna grassland by drought and grazing | O ...

    African Journals Online (AJOL)

    The relative effects of drought and heavy grazing on the floristic composition, population size and and structure, and basal cover of an African savanna grassland were differentiated by comparing changes over eight years over eight years, which included a severe drought year, across a gradient of grazing history. Drought ...

  3. Savanna ecosystem project: phase I summary and phase II progress

    CSIR Research Space (South Africa)

    Huntely, BJ

    1978-07-01

    Full Text Available A summary of the results of the first phase (mid 1974 to mid 1976) of the South African Savanna Ecosystem Project being undertaken at Nylsvley in the northern Transvaal is presented. Phase I of this ten year study of the structure and functioning...

  4. Gene-centric meta-analysis of lipid traits in African, East Asian and Hispanic populations.

    Directory of Open Access Journals (Sweden)

    Clara C Elbers

    Full Text Available Meta-analyses of European populations has successfully identified genetic variants in over 100 loci associated with lipid levels, but our knowledge in other ethnicities remains limited. To address this, we performed dense genotyping of ∼2,000 candidate genes in 7,657 African Americans, 1,315 Hispanics and 841 East Asians, using the IBC array, a custom ∼50,000 SNP genotyping array. Meta-analyses confirmed 16 lipid loci previously established in European populations at genome-wide significance level, and found multiple independent association signals within these lipid loci. Initial discovery and in silico follow-up in 7,000 additional African American samples, confirmed two novel loci: rs5030359 within ICAM1 is associated with total cholesterol (TC and low-density lipoprotein cholesterol (LDL-C (p = 8.8×10(-7 and p = 1.5×10(-6 respectively and a nonsense mutation rs3211938 within CD36 is associated with high-density lipoprotein cholesterol (HDL-C levels (p = 13.5×10(-12. The rs3211938-G allele, which is nearly absent in European and Asian populations, has been previously found to be associated with CD36 deficiency and shows a signature of selection in Africans and African Americans. Finally, we have evaluated the effect of SNPs established in European populations on lipid levels in multi-ethnic populations and show that most known lipid association signals span across ethnicities. However, differences between populations, especially differences in allele frequency, can be leveraged to identify novel signals, as shown by the discovery of ICAM1 and CD36 in the current report.

  5. A long-standing Pleistocene refugium in southern Africa and a mosaic of refugia in East Africa

    DEFF Research Database (Denmark)

    Lorenzen, Eline; Masembe, Charles; Arctander, Peter

    2010-01-01

    Aim Previous genetic studies of African savanna ungulates have indicated Pleistocene refugial areas in East and southern Africa, and recent palynological, palaeovegetation and fossil studies have suggested the presence of a long-standing refugium in the south and a mosaic of refugia in the east....... Phylogeographic analysis of the common eland antelope, Taurotragus oryx (Bovidae), was used to assess these hypotheses and the existence of genetic signatures of Pleistocene climate change. Location The sub-Saharan savanna biome of East and southern Africa. Methods Mitochondrial DNA control-region fragments (414...... bp) from 122 individuals of common eland were analysed to elucidate the phylogeography, genetic diversity, spatial population structuring, historical migration and demographic history of the species. The phylogeographic split among major genetic lineages was dated using Bayesian coalescent...

  6. Blood vitamins and trace elements in Northern-East African cheetahs (Acinonyx jubatus soemmeringii) in captivity in the Middle East.

    Science.gov (United States)

    Beckmann, Katie M; O'Donovan, Declan; McKeown, Sean; Wernery, Ulli; Basu, Puja; Bailey, Tom A

    2013-09-01

    There are few published data regarding the endangered Northern-East African cheetah (Acinonyx jubatus soemmeringii), held in captivity in the Middle East and Europe. Studies have demonstrated a high incidence of disease in captive cheetahs, in which vitamin and trace element imbalances have often been implicated. Blood vitamin and trace element reference values in cheetahs merit further investigation. In this study, blood samples were opportunistically collected from apparently healthy A. j. soemmeringii from two collections (A and B) with successful breeding programs in the United Arab Emirates. The cheetahs were fed whole prey of mixed species (and, in Collection B, goat muscle and bone as well) dusted with vitamin and mineral supplements. Mean serum vitamin and trace element values (for cheetahs > 4 mo in age) were as follows: vitamin A (retinol), 2.20 microM/L (n = 27); vitamin B1, 0.0818 microM/L (n = 45); vitamin C, 28.6 microM/L (n=10); vitamin E (alpha-tocopherol), 35.6 microM/L (n = 27); copper (Cu), 12.53 microM/L (n = 27); selenium (Se), 3.10 microM/L (n = 27); and zinc (Zn), 10.87 microM/L (n = 27). Mean values of vitamin A, vitamin E, Cu, and Zn fell within ranges of published cheetah mean values, and mean Se was lower than range values for cheetahs presented in one previous study; blood vitamin B1 and vitamin C values of cheetahs have not previously been published. The values were taken to indicate that the cheetahs' nutritional status was adequate with regard to those nutrients analyzed. Serum vitamin E was particularly high in cheetahs fed fresh whole prey, and on this basis vitamin E supplementation of fresh whole prey appeared to have been unnecessary. There were differences (P < 0.05) between collections in serum vitamin B1, vitamin E, Cu, and 10 other hematologic and biochemical parameters. Nine hematologic and blood biochemical parameters differed among age categories.

  7. Mineral fertilizer response and nutrient use efficiencies of East African highland banana (Musa spp., AAA-EAHB, cv. Kisansa)

    NARCIS (Netherlands)

    Nyombi, K.; Asten, van P.J.A.; Corbeels, M.; Taulya, G.; Leffelaar, P.A.; Giller, K.E.

    2010-01-01

    Poor yields of East African highland bananas (Musa spp., AAA-EAHB) on smallholder farms have often been attributed to problems of poor soil fertility. We measured the effects of mineral fertilizers on crop performance at two sites over two to three crop cycles; Kawanda in central Uganda and Ntungamo

  8. East African highland bananas (Musa spp. AAA-EA) 'worry' more about potassium deficiency than drought stress

    NARCIS (Netherlands)

    Taulya, G.

    2013-01-01

    Drought stress, potassium (K) and nitrogen (N) deficiencies are major constraints to rain-fed East African highland banana (EAHB) production in Uganda. It was hypothesised that the reduction in fresh bunch mass and increase in dry matter (DM) allocation to corms with drought stress, K and N

  9. Norms for multivariate diagnosis of nutrient imbalance in the East African highland bananas (musa spp.aaa)

    NARCIS (Netherlands)

    Wairegi, L.; Asten, van P.

    2011-01-01

    Despite low yields and soil fertility problems, fertilizer use in the East African Highland banana (AAA-EA) production is absent. High fertilizer costs increase the need for site-specific fertilizer recommendations that address deficiencies. This study aimed to derive and compare norms for AAA-EA

  10. Good Governance and Foreign Direct Investment : A Legal Contribution to a Balanced Economic Development in the East African Community (EAC)

    NARCIS (Netherlands)

    Mbembe, Binda

    2015-01-01

    One of the objectives of the East African Community (EAC) is the promotion of a balanced economic development between its Partner States: Burundi, Kenya, Rwanda, Tanzania, and Uganda. And one of the ways to reach this economic development is the attraction of investment, especially Foreign Direct

  11. Fertility of the Small East African goat following pre-pubertal infection with Trypanosoma congolense

    International Nuclear Information System (INIS)

    O'Hara, H.B.; Gombe, S.

    1991-01-01

    Pre-pubertal male and female Small East African goats were infected with Trypanosoma congolense at 4-5 months of age. Changes in body weight and haemogram were monitored weekly. Progesterone and testosterone measurements were made three times weekly until the goats either reached puberty or 18 months of age. Onset of puberty was determined from observation of oestrus behaviour, mating or increase in libidio; this was confirmed by elevation in plasma progesterone or testosterone levels. Trypanosomiasis affected pre-pubertal goats by reducing body weight gain and delaying onset of puberty. Histological examination of the gonads showed pronounced pathological changes. These effects were reversed by treatment with isometamidium chloride (Samorin, May and Baker). It was concluded that early treatment of infected goats before serious gonadal damage could occur allowed full restoration of reproductive function. (author). 6 refs, 4 figs, 1 tab

  12. The influence of inherited structures on magmatic and amagmatic processes in the East African Rift.

    Science.gov (United States)

    Biggs, J.; Lloyd, R.; Hodge, M.; Robertson, E.; Wilks, M.; Fagereng, A.; Kendall, J. M.; Mdala, H. S.; Lewi, E.; Ayele, A.

    2017-12-01

    The idea that crustal heterogeneities, particularly inherited structures, influence the initiation and evolution of continental rifts is not new, but now modern techniques allow us to explore these controls from a fresh perspective, over a range of lengthscales, timescales and depths. In amagmatic rifts, I will demonstrate that deep fault structure is controlled by the stress orientation during the earliest phase of rifting, while the surface expression exploits near-surface weaknesses. I will show that pre-existing structures control the storage and orientation of deeper magma reservoirs in magmatic rifts, while the tectonic stress regime controls intra-rift faulting and shallow magmatism and stresses related to surface loading and cycles of inflation and deflation dominate at volcanic edifices. Finally, I will show how cross-rift structures influence short-term processes such as deformation and seismicity. I will illustrate the talk throughout using examples from along the East African Rift, including Malawi, Tanzania, Kenya and Ethiopia.

  13. Predicting East African spring droughts using Pacific and Indian Ocean sea surface temperature indices

    Science.gov (United States)

    Funk, Christopher C.; Hoell, Andrew; Shukla, Shraddhanand; Blade, Ileana; Liebmann, Brant; Roberts, Jason B.; Robertson, Franklin R.

    2014-01-01

    In southern Ethiopia, Eastern Kenya, and southern Somalia poor boreal spring rains in 1999, 2000, 2004, 2007, 2008, 2009 and 2011 contributed to severe food insecurity and high levels of malnutrition. Predicting rainfall deficits in this region on seasonal and decadal time frames can help decision makers support disaster risk reduction while guiding climate-smart adaptation and agricultural development. Building on recent research that links more frequent droughts to a stronger Walker Circulation, warming in the Indo-Pacific warm pool, and an increased western Pacific sea surface temperature (SST) gradient, we explore the dominant modes of East African rainfall variability, links between these modes and sea surface temperatures, and a simple index-based monitoring-prediction system suitable for drought early warning.

  14. Seasonal patterns of mixed species groups in large East African mammals.

    Science.gov (United States)

    Kiffner, Christian; Kioko, John; Leweri, Cecilia; Krause, Stefan

    2014-01-01

    Mixed mammal species groups are common in East African savannah ecosystems. Yet, it is largely unknown if co-occurrences of large mammals result from random processes or social preferences and if interspecific associations are consistent across ecosystems and seasons. Because species may exchange important information and services, understanding patterns and drivers of heterospecific interactions is crucial for advancing animal and community ecology. We recorded 5403 single and multi-species clusters in the Serengeti-Ngorongoro and Tarangire-Manyara ecosystems during dry and wet seasons and used social network analyses to detect patterns of species associations. We found statistically significant associations between multiple species and association patterns differed spatially and seasonally. Consistently, wildebeest and zebras preferred being associated with other species, whereas carnivores, African elephants, Maasai giraffes and Kirk's dik-diks avoided being in mixed groups. During the dry season, we found that the betweenness (a measure of importance in the flow of information or disease) of species did not differ from a random expectation based on species abundance. In contrast, in the wet season, we found that these patterns were not simply explained by variations in abundances, suggesting that heterospecific associations were actively formed. These seasonal differences in observed patterns suggest that interspecific associations may be driven by resource overlap when resources are limited and by resource partitioning or anti-predator advantages when resources are abundant. We discuss potential mechanisms that could drive seasonal variation in the cost-benefit tradeoffs that underpin the formation of mixed-species groups.

  15. Khat chewing and acculturation in East-African migrants living in Frankfurt am Main/Germany.

    Science.gov (United States)

    Bongard, Stephan; Nakajima, Motohiro; al'Absi, Mustafa

    2015-04-22

    Khat (Catha edulis, Forsk) is a drug widely used in countries around the Red Sea (East-Africa and Arabian Peninsula). In Germany khat chewing is illegal but nevertheless an often observed habit in immigrants from this region. This study investigates the interrelation between immigrants acculturation processes and traditional khat chewing habits. Sixty-one khat chewers (14 female) from East-African countries were interviewed about their khat chewing habits and acculturation strategy using standardized questionnaires. Results indicate that immigrants׳ khat chewing behaviors are similar to what is common in countries with traditional khat use. But khat chewing tended to be less among immigrants who were relatively more oriented towards their cultures of origin. Chewing khat was subjectively considered to help coping with problems, to forget bad memories and to concentrate better. It was concluded that khat chewing serves a functional use of coping with stressful events in the present or in the past within this sample. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  16. Breeding performance of the grasshopper buzzard (Butastur rufipennis) in a natural and a human-modified West African savanna

    NARCIS (Netherlands)

    Buij, Ralph; Kortekaas, Kim; van Krimpen, Roderick R. D.; van Wijk, Rien; van der Zanden, Saskia; de Iongh, Hans H.; Heitkonig, Ignas M. A.; de Snoo, Geert R.; Komdeur, Jan; Heitkönig, Ignas M.A.

    Few studies have examined raptor reproduction in response to land-use change in sub-Saharan Africa, hampering conservation efforts to address regional declines. To further our understanding of mechanisms underlying the dramatic declines of West African raptors, we examined the relationship between

  17. Extremes in East African hydroclimate and links to Indo-Pacific variability on interannual to decadal timescales

    Science.gov (United States)

    Ummenhofer, Caroline C.; Kulüke, Marco; Tierney, Jessica E.

    2018-04-01

    East African hydroclimate exhibits considerable variability across a range of timescales, with implications for its population that depends on the region's two rainy seasons. Recent work demonstrated that current state-of-the-art climate models consistently underestimate the long rains in boreal spring over the Horn of Africa while overestimating the short rains in autumn. This inability to represent the seasonal cycle makes it problematic for climate models to project changes in East African precipitation. Here we consider whether this bias also has implications for understanding interannual and decadal variability in the East African long and short rains. Using a consistent framework with an unforced multi-century global coupled climate model simulation, the role of Indo-Pacific variability for East African rainfall is compared across timescales and related to observations. The dominant driver of East African rainfall anomalies critically depends on the timescale under consideration: Interannual variations in East African hydroclimate coincide with significant sea surface temperature (SST) anomalies across the Indo-Pacific, including those associated with the El Niño-Southern Oscillation (ENSO) in the eastern Pacific, and are linked to changes in the Walker circulation, regional winds and vertical velocities over East Africa. Prolonged drought/pluvial periods in contrast exhibit anomalous SST predominantly in the Indian Ocean and Indo-Pacific warm pool (IPWP) region, while eastern Pacific anomalies are insignificant. We assessed dominant frequencies in Indo-Pacific SST and found the eastern equatorial Pacific dominated by higher-frequency variability in the ENSO band, while the tropical Indian Ocean and IPWP exhibit lower-frequency variability beyond 10 years. This is consistent with the different contribution to regional precipitation anomalies for the eastern Pacific versus Indian Ocean and IPWP on interannual and decadal timescales, respectively. In the model

  18. Exploring Pacific Climate Variability and Its Impacts on East African Water Resources and Food Security

    Science.gov (United States)

    Funk, C. C.; Hoerling, M. P.; Hoell, A.; Liebmann, B.; Verdin, J. P.; Eilerts, G.

    2014-12-01

    In 8 out the past 15 boreal springs (1999, 2000, 2004, 2008, 2009, 2011, 2012, and 2013), substantial parts of eastern East Africa experienced very low boreal spring rains. These rainfall deficits have triggered widespread food insecurity, and even contributed to the outbreak of famine conditions in Somalia in 2011. At both seasonal and decadal time scales, new science supported by the USAID Famine Early Warning Systems Network seeks to understand the mechanisms producing these droughts. We present research suggesting that the ultimate and proximate causes of these increases in aridity are i) stronger equatorial Pacific SST gradients and ii) associated increases in the strength of the Indo-Pacific Walker circulation. Using observations and new modeling ensembles, we explore the relative contributions of Pacific Decadal Variability (PDV) and global warming under warm and cold east Pacific Ocean states. This question is addressed in two ways: by using atmospheric GCMs forced with full and ENSO-only SSTs, and ii) by decomposing coupled ocean-atmosphere climate simulations into PDV and non-PDV components. These analyses allow us to explore the Walker circulation's sensitivity to climate change under various PDV states, and inform a tentative bracketing of 2030 climate conditions. We conclude by discussing links to East African development. Regions of high rainfall sensitivity are delineated and intersected with recent changes in population and land cover/land use. The interaction of elevation and climate is shown to create climatically secure regions that are likely to remain viable even under drier and warmer conditions; such regions may be logical targets for agricultural intensification. Conversely, arid low elevation regions are likely to experience substantial temperature impacts. Continued expansion into these areas may effectively create more 'drought' even if rainfall increases.

  19. Bioenergy from agro-industrial residues in the East African region. Summary report

    Energy Technology Data Exchange (ETDEWEB)

    Jungersen, G. [Dansk Teknologisk Inst. (Denmark); Kivaisi, A.; Rubindamayugi, M. [Univ. of Dar es Salaam (Tanzania, United Republic of)

    1998-05-01

    Tanzania has recently developed a comprehensive environmental policy which has put high priority on several specific environmental issues. One of the issues is the quality of waste water. A special priority is given to the pollution from the sisal industry. The East-African agro-industries generate very large quantities of organic residues from production and processing of different crops. These residues form a major contribution to the pollution of air, soil and waterways, but, at the same time they constitute a large potential for production of bioenergy through anaerobic digestion as well as potential substrate for other biological fermentation processes. Generally, these residues are regarded as having no or very little value and the different disposal methods are mainly a matter of getting rid of the waste. The generation of residues are very often concentrated on few large units, which makes the exploitation of these resources feasible in large scale biogas systems. Typically the units will have a potential of a daily methane generation of 1,000-20,000 m{sup 3} CH{sub 4}, equivalent to a potential electricity production of 0.2-3.2 MW. The future utilization of these resources for production of valuable products is described in this report. This report consists of 3 volumes. This summary report including the main objectives and findings from the different project report: Mapping and Quantification of Organic Agro-Industrial Residues in East Africa; Biogas - Bioenergy Potential in East Africa, Seminar Proceedings, Siler Sands, Dar es Salaam 22-23 September 1997; Bioenergy from Sisal residues - Experimental results and Capacity Building Activities. (EG)

  20. Mainstreaming biodiversity and wildlife management into climate change policy frameworks in selected east and southern African countries

    Directory of Open Access Journals (Sweden)

    Olga L. Kupika

    2016-04-01

    Full Text Available The Rio+20 outcomes document, the Future We Want, enshrines green economy as one of the platforms to attain sustainable development and calls for measures that seek to address climate change and biodiversity management. This paper audits climate change policies from selected east and southern African countries to determine the extent to which climate change legislation mainstreams biodiversity and wildlife management. A scan of international, continental, regional and national climate change policies was conducted to assess whether they include biodiversity and/or wildlife management issues. The key finding is that many climate change policy–related documents, particularly the National Adaptation Programme of Actions (NAPAs, address threats to biodiversity and wildlife resources. However, international policies like the United Nations Framework Convention on Climate Change and Kyoto Protocol do not address the matter under deliberation. Regional climate change policies such as the East African Community, Common Market for Eastern and Southern Africa and African Union address biodiversity and/or wildlife issues whilst the Southern African Development Community region does not have a stand-alone policy for climate change. Progressive countries like Rwanda, Uganda, Tanzania and Zambia have recently put in place detailed NAPAs which are mainstream responsive strategies intended to address climate change adaptation in the wildlife sector. Keywords: mainstreaming, biodiversity, wildlife, climate change policy, east and southern Africa

  1. An interdisciplinary approach for groundwater management in area contaminated by fluoride in East African Rift System

    Science.gov (United States)

    Da Pelo, Stefania; Melis, M. Teresa; Dessì, Francesco; Pistis, Marco; Funedda, Antonio; Oggiano, Giacomo; Carletti, Alberto; Soler Gil, Albert; Barbieri, Manuela; Pittalis, Daniele; Ghiglieri, Giorgio

    2017-04-01

    Groundwater is the main source of fresh water supply for most of the rural communities in Africa (approximately 75% of Africans has confidence in groundwater as their major source of drinking water). Many African countries has affected by high fluoride concentration in groundwater (up to 90 mg/L), generating the contamination of waters, soils and food, in particular in the eastern part of the continent. It seems that fluoride concentration is linked to geology of the Rift Valley: geogenic occurrence of fluoride is often connected to supergenic enrichment due to the weathering of alkaline volcanic rocks, fumaric gases and presence of thermal waters. The H2020 project FLOWERED (de-FLuoridation technologies for imprOving quality of WatEr and agRo-animal products along the East African Rift Valley in the context of aDaptation to climate change) wish to address environmental and health (human and animal) issues associated to the fluoride contamination in the African Rift Valley, in particular in three case study area located in Ethiopia, Tanzania and Kenya. FLOWERED aims to develop an integrated, sustainable and participative water and agriculture management at a cross-boundary catchment scale through a strong interdisciplinary research approach. It implies knowledge of geology, hydrogeology, mineralogy, geochemistry, agronomy, crop and animal sciences, engineering, technological sciences, data management and software design, economics and communication. The proposed approach is based on a detailed knowledge of the hydrogeological setting, with the identification and mapping of the specific geological conditions of water contamination and its relation with the different land uses. The East African Rift System (EARS) groundwater circulation and storage, today already poorly understood, is characterized by a complex arrangement of aquifers. It depends on the type of porosity and permeability created during and after the rock formation, and is strongly conditioned by the

  2. Genetic diversity and connectivity in the East African giant mud crab Scylla serrata: Implications for fisheries management.

    Directory of Open Access Journals (Sweden)

    Cyrus Rumisha

    Full Text Available The giant mud crab Scylla serrata provides an important source of income and food to coastal communities in East Africa. However, increasing demand and exploitation due to the growing coastal population, export trade, and tourism industry are threatening the sustainability of the wild stock of this species. Because effective management requires a clear understanding of the connectivity among populations, this study was conducted to assess the genetic diversity and connectivity in the East African mangrove crab S. serrata. A section of 535 base pairs of the cytochrome oxidase subunit I (COI gene and eight microsatellite loci were analysed from 230 tissue samples of giant mud crabs collected from Kenya, Tanzania, Mozambique, Madagascar, and South Africa. Microsatellite genetic diversity (He ranged between 0.56 and 0.6. The COI sequences showed 57 different haplotypes associated with low nucleotide diversity (current nucleotide diversity = 0.29%. In addition, the current nucleotide diversity was lower than the historical nucleotide diversity, indicating overexploitation or historical bottlenecks in the recent history of the studied population. Considering that the coastal population is growing rapidly, East African countries should promote sustainable fishing practices and sustainable use of mangrove resources to protect mud crabs and other marine fauna from the increasing pressure of exploitation. While microsatellite loci did not show significant genetic differentiation (p > 0.05, COI sequences revealed significant genetic divergence between sites on the East coast of Madagascar (ECM and sites on the West coast of Madagascar, mainland East Africa, as well as the Seychelles. Since East African countries agreed to achieve the Convention on Biological Diversity (CBD target to protect over 10% of their marine areas by 2020, the observed pattern of connectivity and the measured genetic diversity can serve to provide useful information for designing

  3. Spatial patterns of sea surface temperature influences on East African precipitation as revealed by empirical orthogonal teleconnections

    Directory of Open Access Journals (Sweden)

    Tim eAppelhans

    2016-02-01

    Full Text Available East Africa is characterized by a rather dry annual precipitation climatology with two distinct rainy seasons. In order to investigate sea surface temperature driven precipitation anomalies for the region we use the algorithm of empirical orthogonal teleconnection analysis as a data mining tool. We investigate the entire East African domain as well as 5 smaller sub-regions mainly located in areas of mountainous terrain. In searching for influential sea surface temperature patterns we do not focus any particular season or oceanic region. Furthermore, we investigate different time lags from zero to twelve months. The strongest influence is identified for the immediate (i.e. non-lagged influences of the Indian Ocean in close vicinity to the East African coast. None of the most important modes are located in the tropical Pacific Ocean, though the region is sometimes coupled with the Indian Ocean basin. Furthermore, we identify a region in the southern Indian Ocean around the Kerguelen Plateau which has not yet been reported in the literature with regard to precipitation modulation in East Africa. Finally, it is observed that not all regions in East Africa are equally influenced by the identified patterns.

  4. East African Crisis Response: Shaping Ethiopian Peace Force for Better Participation in Future Peace Operations

    National Research Council Canada - National Science Library

    Amdemichael, Haile A

    2006-01-01

    .... This thesis analyzes the Organization of African Unity/African Union (OAU/AU) efforts after the Cold War to restore security and ensure stability in the region and outlines the process of creating African Standby Forces (ASF...

  5. Grenvillian vs Pan-African tectonic evolution in the Gamburtsev Province of East Antarctica

    Science.gov (United States)

    Ferraccioli, F.; Guochao, W.; Finn, C.; Bell, R. E.

    2017-12-01

    The Gamburtsev Subglacial Mountains in interior East Antarctica are underlain by 50-60 km thick crust. In contrast, the Archean to Mesoproterozoic Mawson craton that occupies the Wilkes and Terre Adelie region features only 40-45 km thick crust. The Gamburtsev Province is underlain by 200 km thick lithoshere, as typically observed over Precambrian lithosphere that has not been substantially reworked during Phanerozoic subduction or collision. Ferraccioli et al., (2011) proposed that a segment of a stalled orogen (i.e. an orogen where widespread orogenic collapse and root delamination has not occurred) is preserved in the Gamburtsev Province and hypothesised that its origin relates to accretionary and subsequent collisional events at ca 1 Ga, linked to the assembly of Rodinia. However, passive seismic interpretations indicate that crustal thickening may relate instead to Pan-African age assembly of Gondwana (at ca 550 Ma). Here we interpret a set of enhanced magnetic and gravity images, depth to magnetic and gravity sources and 2D and forward and inverse models to characterise the crustal architecture of the Gamburtsev Province. Enhanced aeromagnetic images reveal a system of subglacial faults that segment the Gamburtsev Province into three distinct geophysical domains, the northern, central and southern domains. Apparent offsets in high-frequency magnetic anomalies within the central domain are interpreted as revealing a transpressional fault system parallel to the previously proposed Gamburtsev Suture. Our magnetic and gravity model, combined with independent constraints from sediment provenance ages, is interpreted as revealing arc and back arc terranes of inferred Grenvillian age in the northern and Central domains of the Gambrurtsev Province. Distinct magnetic anomalies correspond to inferred Paleoproterozoic crust that may have affinities with the Lambert Terrane and the South Pole Province, an inferred Mesoproterozoic (1.6-1.4 Ga?) igneous province. We

  6. Seasonal patterns of mixed species groups in large East African mammals.

    Directory of Open Access Journals (Sweden)

    Christian Kiffner

    Full Text Available Mixed mammal species groups are common in East African savannah ecosystems. Yet, it is largely unknown if co-occurrences of large mammals result from random processes or social preferences and if interspecific associations are consistent across ecosystems and seasons. Because species may exchange important information and services, understanding patterns and drivers of heterospecific interactions is crucial for advancing animal and community ecology. We recorded 5403 single and multi-species clusters in the Serengeti-Ngorongoro and Tarangire-Manyara ecosystems during dry and wet seasons and used social network analyses to detect patterns of species associations. We found statistically significant associations between multiple species and association patterns differed spatially and seasonally. Consistently, wildebeest and zebras preferred being associated with other species, whereas carnivores, African elephants, Maasai giraffes and Kirk's dik-diks avoided being in mixed groups. During the dry season, we found that the betweenness (a measure of importance in the flow of information or disease of species did not differ from a random expectation based on species abundance. In contrast, in the wet season, we found that these patterns were not simply explained by variations in abundances, suggesting that heterospecific associations were actively formed. These seasonal differences in observed patterns suggest that interspecific associations may be driven by resource overlap when resources are limited and by resource partitioning or anti-predator advantages when resources are abundant. We discuss potential mechanisms that could drive seasonal variation in the cost-benefit tradeoffs that underpin the formation of mixed-species groups.

  7. Development of catchment research, with particular attention to Plynlimon and its forerunner, the East African catchments

    Science.gov (United States)

    Blackie, J. R.; Robinson, M.

    2007-01-01

    Dr J.S.G. McCulloch was deeply involved in the establishment of research catchments in East Africa and subsequently in the UK to investigate the hydrological consequences of changes in land use. Comparison of these studies provides an insight into how influential his inputs and direction have been in the progressive development of the philosophy, the instrumentation and the analytical techniques now employed in catchment research. There were great contrasts in the environments: tropical highland (high radiation, intense rainfall) vs. temperate maritime (low radiation and frontal storms), contrasting soils and vegetation types, as well as the differing social and economic pressures in developing and developed nations. Nevertheless, the underlying scientific philosophy was common to both, although techniques had to be modified according to local conditions. As specialised instrumentation and analytical techniques were developed for the UK catchments many were also integrated into the East African studies. Many lessons were learned in the course of these studies and from the experiences of other studies around the world. Overall, a rigorous scientific approach was developed with widespread applicability. Beyond the basics of catchment selection and the quantification of the main components of the catchment water balance, this involved initiating parallel process studies to provide information on specific aspects of catchment behaviour. This information could then form the basis for models capable of extrapolation from the observed time series to other periods/hydrological events and, ultimately, the capability of predicting the consequences of changes in catchment land management to other areas in a range of climates.

  8. Malaria in east African highlands during the past 30 years: impact of environmental changes

    Directory of Open Access Journals (Sweden)

    Yousif El - Safi Himeidan

    2012-08-01

    Full Text Available East African highlands are one of the most populated regions in Africa. The population densities in the highlands ranged between 158 persons/km2 in Ethiopia to 410 persons/km2 in Rwanda. According to the United Nations Population Fund, the region has the world's highest population growth rate. These factors are likely behind the high rates of poverty among the populations. As there were no employment opportunities other than agricultural, this demographic pressure of poor populations have included in an extensive unprecedented land use and land cover changes such as modification of bushland, woodland, and grassland on hillsides to farmland and transformation of papyrus swamps in valley bottoms to dairy pastures and cropland and changing of fallows on hillsides from short or seasonal to longer or perennial. Areas harvested for food crops were therefore increased by more than 100% in most of the highlands. The lost of forest areas, mainly due to subsistence agriculture, between 1990 - 2010 ranged between 8000 ha in Rwanda to 2838000 ha in Ethiopia. These unmitigated environmental changes in the highlands led to rise temperature and optimizing the spread and survival of malaria vectors and development of malaria parasites. Malaria in highlands was initially governed by low ambient temperature, trend of malaria transmission was therefore increased and several epidemics were observed in late 1980s and early 2000s. Although, malaria is decreasing through intensified interventions since mid 2000s onwards, these environmental changes might expose population in the highlands of east Africa to an increase risk of malaria and its epidemic particularly if the current interventions are not sustained.

  9. The lithosphere of the East African Rift and Plateau (Afar-Ethiopia-Turkana) : insights from Integrated 3-D density modelling

    OpenAIRE

    Woldetinsae, Girma

    2005-01-01

    The area encompassing the Eastern branch of the East African Rift System (EARS: Afar-Ethiopia-Turkana) and associated plateaux is an ideal region to investigate extension and magmatism associated with rupturing continental lithosphere. Ethiopia covers an important part of the EARS. It contains the major section of the ca. 5000 km Afro-Arabian rift and includes the transition between the Arabo-Nubian-Shield and the Mozambique Belt. A compilation of over 45000 onshore and offshore gravity stati...

  10. The episode of genetic drift defining the migration of humans out of Africa is derived from a large east African population size.

    Directory of Open Access Journals (Sweden)

    Nuha Elhassan

    Full Text Available Human genetic variation particularly in Africa is still poorly understood. This is despite a consensus on the large African effective population size compared to populations from other continents. Based on sequencing of the mitochondrial Cytochrome C Oxidase subunit II (MT-CO2, and genome wide microsatellite data we observe evidence suggesting the effective size (Ne of humans to be larger than the current estimates, with a foci of increased genetic diversity in east Africa, and a population size of east Africans being at least 2-6 fold larger than other populations. Both phylogenetic and network analysis indicate that east Africans possess more ancestral lineages in comparison to various continental populations placing them at the root of the human evolutionary tree. Our results also affirm east Africa as the likely spot from which migration towards Asia has taken place. The study reflects the spectacular level of sequence variation within east Africans in comparison to the global sample, and appeals for further studies that may contribute towards filling the existing gaps in the database. The implication of these data to current genomic research, as well as the need to carry out defined studies of human genetic variation that includes more African populations; particularly east Africans is paramount.

  11. Giant seismites and megablock uplift in the East African Rift: evidence for Late Pleistocene large magnitude earthquakes.

    Science.gov (United States)

    Hilbert-Wolf, Hannah Louise; Roberts, Eric M

    2015-01-01

    In lieu of comprehensive instrumental seismic monitoring, short historical records, and limited fault trench investigations for many seismically active areas, the sedimentary record provides important archives of seismicity in the form of preserved horizons of soft-sediment deformation features, termed seismites. Here we report on extensive seismites in the Late Quaternary-Recent (≤ ~ 28,000 years BP) alluvial and lacustrine strata of the Rukwa Rift Basin, a segment of the Western Branch of the East African Rift System. We document examples of the most highly deformed sediments in shallow, subsurface strata close to the regional capital of Mbeya, Tanzania. This includes a remarkable, clastic 'megablock complex' that preserves remobilized sediment below vertically displaced blocks of intact strata (megablocks), some in excess of 20 m-wide. Documentation of these seismites expands the database of seismogenic sedimentary structures, and attests to large magnitude, Late Pleistocene-Recent earthquakes along the Western Branch of the East African Rift System. Understanding how seismicity deforms near-surface sediments is critical for predicting and preparing for modern seismic hazards, especially along the East African Rift and other tectonically active, developing regions.

  12. Use of Machine Learning Techniques for Iidentification of Robust Teleconnections to East African Rainfall Variability in Observations and Models

    Science.gov (United States)

    Roberts, J. Brent; Robertson, Franklin R.; Funk, Chris

    2014-01-01

    Providing advance warning of East African rainfall variations is a particular focus of several groups including those participating in the Famine Early Warming Systems Network. Both seasonal and long-term model projections of climate variability are being used to examine the societal impacts of hydrometeorological variability on seasonal to interannual and longer time scales. The NASA / USAID SERVIR project, which leverages satellite and modeling-based resources for environmental decision making in developing nations, is focusing on the evaluation of both seasonal and climate model projections to develop downscaled scenarios for using in impact modeling. The utility of these projections is reliant on the ability of current models to capture the embedded relationships between East African rainfall and evolving forcing within the coupled ocean-atmosphere-land climate system. Previous studies have posited relationships between variations in El Niño, the Walker circulation, Pacific decadal variability (PDV), and anthropogenic forcing. This study applies machine learning methods (e.g. clustering, probabilistic graphical model, nonlinear PCA) to observational datasets in an attempt to expose the importance of local and remote forcing mechanisms of East African rainfall variability. The ability of the NASA Goddard Earth Observing System (GEOS5) coupled model to capture the associated relationships will be evaluated using Coupled Model Intercomparison Project Phase 5 (CMIP5) simulations.

  13. A One-Size-Fits-All HIV Prevention and Education Approach?: Interpreting Divergent HIV Risk Perceptions Between African American and East African Immigrant Women in Washington, DC Using the Proximate-Determinants Conceptual Framework.

    Science.gov (United States)

    De Jesus, Maria; Taylor, Juanita; Maine, Cathleen; Nalls, Patricia

    2016-02-01

    To date, there are very few comparative US studies and none in DC that distinguish between US-born and foreign-born black women to examine and compare their perceptions of HIV risk. This qualitative study, therefore, analyzes African American and East African women's perceptions of HIV risk in the Washington DC Metropolitan area, which has the highest AIDS rate in the United States. Forty in-depth, semistructured interviews and 10 cognitive interviews were conducted among a sample of 25 African American women and 25 East African born women between October 2012 and March 2013 to examine perceptions regarding HIV risk. The in-depth semistructured interviews were preceded by the cognitive interviews and accompanying survey. Study protocol was reviewed and approved by the American University Institutional Review Board. Adopting Boerma and Weir's Proximate Determinants conceptual framework to interpret the data, the results of the study demonstrate that African American and East African immigrant women have divergent perceptions of HIV risk. Although African American women ascribe HIV risk to individual-level behaviors and choices such as unprotected sex, East African women attribute HIV risk to conditions of poverty and survival. Study findings suggest that addressing HIV prevention and education among black women in DC will require distinct and targeted strategies that are culturally and community-centered to resonate with these different audiences.

  14. A one-size-fits-all HIV prevention and education approach?: Analyzing and interpreting divergent HIV risk perceptions between African American and East African immigrant women in Washington, DC

    Science.gov (United States)

    De Jesus, Maria; Taylor, Juanita; Maine, Cathleen; Nalls, Patricia

    2015-01-01

    Background To date, there are very few comparative US studies and none in DC that distinguish between US-born and foreign-born Black women to examine and compare their perceptions of HIV risk. This qualitative study, therefore, analyzes African American and East African women’s perceptions of HIV risk in the Washington DC Metropolitan area, which has the highest AIDS rate in the US. Methods Forty in-depth, semi-structured interviews and 10 cognitive interviews were conducted among a sample of 25 African American women and 25 East African born women between October 2012 and March 2013 to examine perceptions regarding HIV risk. The in-depth semi-structured interviews were preceded by the cognitive interviews and accompanying survey. Study protocol was reviewed and approved by the American University Institutional Review Board. Results Adopting Boerma and Weir’s Proximate Determinants conceptual framework to interpret the data, the results of the study demonstrate that African American and East African immigrant women have divergent perceptions of HIV risk. While African American women ascribe HIV risk to individual-level behaviors and choices such as unprotected sex, East African women attribute HIV risk to conditions of poverty and survival. Conclusions Study findings suggest that addressing HIV prevention and education among Black women in DC will require distinct and targeted strategies that are culturally and community-centered in order to resonate with these different audiences. PMID:26766523

  15. Attitudes, perceptions, and behaviors toward HIV testing among African American and East African immigrant women in Washington, D.C.: Implications for targeted HIV testing promotion and communication strategies

    Science.gov (United States)

    De Jesus, Maria; Carrete, Claudia; Maine, Cathleen; Nalls, Patricia

    2015-01-01

    Objectives The objective of the study was to examine and compare the HIV testing attitudes, perceptions, and behaviors between African American and East African immigrant women in the Washington, D.C. Metropolitan area. Methods Adopting an inductive, qualitative methodological approach, we conducted a total of 40 in-depth, semi-structured interviews between October 2012 and March 2013. Qualitative thematic analysis was used to analyze the data. Results Overall, African American women held more favorable views toward HIV testing than East African immigrant women. Very few East African immigrant women sought HIV testing intentionally. The majority of East African participants were tested inadvertently, while others tested for immigration- or employment-related purposes. There were many barriers that impede women from seeking an HIV test including: negative assumptions (e.g., ‘Getting an HIV test implies that I am HIV positive’); negative emotions (e.g., ‘Fear of being diagnosed with HIV and what this will mean for me’); and potential negative reactions from partner or others (e.g., ‘Getting an HIV test can signal distrust, disrespect, or infidelity’). There were nuances in how each group articulated some of these barriers and East African women expressed unique concerns that originated from experiences in their home countries. Conclusions The study shed light into the complexity of factors that constrain women from presenting themselves voluntarily for an HIV test and highlighted the nuances between African American and East African perceptions. Implications of findings for effective targeted HIV screening promotion and communication strategies among these groups of women are discussed. PMID:25897146

  16. Relevance of East African Drill Cores to Human Evolution: the Case of the Olorgesailie Drilling Project

    Science.gov (United States)

    Potts, R.

    2016-12-01

    Drill cores reaching the local basement of the East African Rift were obtained in 2012 south of the Olorgesailie Basin, Kenya, 20 km from excavations that document key benchmarks in the origin of Homo sapiens. Sediments totaling 216 m were obtained from two drilling locations representing the past 1 million years. The cores were acquired to build a detailed environmental record spatially associated with the transition from Acheulean to Middle Stone Age technology and extensive turnover in mammalian species. The project seeks precise tests of how climate dynamics and tectonic events were linked with these transitions. Core lithology (A.K. Behrensmeyer), geochronology (A. Deino), diatoms (R.B. Owen), phytoliths (R. Kinyanjui), geochemistry (N. Rabideaux, D. Deocampo), among other indicators, show evidence of strong environmental variability in agreement with predicted high-eccentricity modulation of climate during the evolutionary transitions. Increase in hominin mobility, elaboration of symbolic behavior, and concurrent turnover in mammalian species indicating heightened adaptability to unpredictable ecosystems, point to a direct link between the evolutionary transitions and the landscape dynamics reflected in the Olorgesailie drill cores. For paleoanthropologists and Earth scientists, any link between evolutionary transitions and environmental dynamics requires robust evolutionary datasets pertinent to how selection, extinction, population divergence, and other evolutionary processes were impacted by the dynamics uncovered in drill core studies. Fossil and archeological data offer a rich source of data and of robust environment-evolution explanations that must be integrated into efforts by Earth scientists who seek to examine high-resolution climate records of human evolution. Paleoanthropological examples will illustrate the opportunities that exist for connecting evolutionary benchmarks to the data obtained from drilled African muds. Project members: R. Potts, A

  17. Trading or coercion? Variation in male mating strategies between two communities of East African chimpanzees.

    Science.gov (United States)

    Kaburu, Stefano S K; Newton-Fisher, Nicholas E

    2015-06-01

    Across taxa, males employ a variety of mating strategies, including sexual coercion and the provision, or trading, of resources. Biological market theory (BMT) predicts that trading of commodities for mating opportunities should exist only when males cannot monopolize access to females and/or obtain mating by force, in situations where power differentials between males are low; both coercion and trading have been reported for chimpanzees ( Pan troglodytes ). Here, we investigate whether the choice of strategy depends on the variation in male power differentials, using data from two wild communities of East African chimpanzees ( Pan troglodytes schweinfurthii ): the structurally despotic Sonso community (Budongo, Uganda) and the structurally egalitarian M-group (Mahale, Tanzania). We found evidence of sexual coercion by male Sonso chimpanzees, and of trading-of grooming for mating-by M-group males; females traded sex for neither meat nor protection from male aggression. Our results suggest that the despotism-egalitarian axis influences strategy choice: male chimpanzees appear to pursue sexual coercion when power differentials are large and trading when power differentials are small and coercion consequently ineffective. Our findings demonstrate that trading and coercive strategies are not restricted to particular chimpanzee subspecies; instead, their occurrence is consistent with BMT predictions. Our study raises interesting, and as yet unanswered, questions regarding female chimpanzees' willingness to trade sex for grooming, if doing so represents a compromise to their fundamentally promiscuous mating strategy. It highlights the importance of within-species cross-group comparisons and the need for further study of the relationship between mating strategy and dominance steepness.

  18. Oral Health Inequalities between Rural and Urban Populations of the African and Middle East Region.

    Science.gov (United States)

    Ogunbodede, E O; Kida, I A; Madjapa, H S; Amedari, M; Ehizele, A; Mutave, R; Sodipo, B; Temilola, S; Okoye, L

    2015-07-01

    Although there have been major improvements in oral health, with remarkable advances in the prevention and management of oral diseases, globally, inequalities persist between urban and rural communities. These inequalities exist in the distribution of oral health services, accessibility, utilization, treatment outcomes, oral health knowledge and practices, health insurance coverage, oral health-related quality of life, and prevalence of oral diseases, among others. People living in rural areas are likely to be poorer, be less health literate, have more caries, have fewer teeth, have no health insurance coverage, and have less money to spend on dental care than persons living in urban areas. Rural areas are often associated with lower education levels, which in turn have been found to be related to lower levels of health literacy and poor use of health care services. These factors have an impact on oral health care, service delivery, and research. Hence, unmet dental care remains one of the most urgent health care needs in these communities. We highlight some of the conceptual issues relating to urban-rural inequalities in oral health, especially in the African and Middle East Region (AMER). Actions to reduce oral health inequalities and ameliorate rural-urban disparity are necessary both within the health sector and the wider policy environment. Recommended actions include population-specific oral health promotion programs, measures aimed at increasing access to oral health services in rural areas, integration of oral health into existing primary health care services, and support for research aimed at informing policy on the social determinants of health. Concerted efforts must be made by all stakeholders (governments, health care workforce, organizations, and communities) to reduce disparities and improve oral health outcomes in underserved populations. © International & American Associations for Dental Research 2015.

  19. Energy consumption, economic growth and CO2 emissions in Middle East and North African countries

    International Nuclear Information System (INIS)

    Arouri, Mohamed El Hedi; Ben Youssef, Adel; M'henni, Hatem; Rault, Christophe

    2012-01-01

    This article extends the recent findings of , , and by implementing recent bootstrap panel unit root tests and cointegration techniques to investigate the relationship between carbon dioxide emissions, energy consumption, and real GDP for 12 Middle East and North African Countries (MENA) over the period 1981–2005. Our results show that in the long-run energy consumption has a positive significant impact on CO 2 emissions. More interestingly, we show that real GDP exhibits a quadratic relationship with CO 2 emissions for the region as a whole. However, although the estimated long-run coefficients of income and its square satisfy the EKC hypothesis in most studied countries, the turning points are very low in some cases and very high in other cases, hence providing poor evidence in support of the EKC hypothesis. CO 2 emission reductions per capita have been achieved in the MENA region, even while the region exhibited economic growth over the period 1981–2005. The econometric relationships derived in this paper suggest that future reductions in CO 2 emissions per capita might be achieved at the same time as GDP per capita in the MENA region continues to grow. - Highlights: ► We study the links between CO 2 emissions, energy consumption and GDP in MENA region. ► Energy consumption has a positive correlation with CO 2 emissions. ► GDP exhibits a quadratic relationship with CO 2 emissions for the region as a whole. ► However, the turning points are low in some cases and high in other cases. ► Thus, not all countries need to sacrifice economic growth to decrease CO 2 emissions.

  20. Distinct subspecies or phenotypic plasticity? Genetic and morphological differentiation of mountain honey bees in East Africa.

    Science.gov (United States)

    Gruber, Karl; Schöning, Caspar; Otte, Marianne; Kinuthia, Wanja; Hasselmann, Martin

    2013-09-01

    Identifying the forces shaping intraspecific phenotypic and genotypic divergence are of key importance in evolutionary biology. Phenotypic divergence may result from local adaptation or, especially in species with strong gene flow, from pronounced phenotypic plasticity. Here, we examine morphological and genetic divergence among populations of the western honey bee Apis mellifera in the topographically heterogeneous East African region. The currently accepted "mountain refugia hypothesis" states that populations living in disjunct montane forests belong to a different lineage than those in savanna habitats surrounding these forests. We obtained microsatellite data, mitochondrial sequences, and morphometric data from worker honey bees collected from feral colonies in three montane forests and corresponding neighboring savanna regions in Kenya. Honey bee colonies from montane forests showed distinct worker morphology compared with colonies in savanna areas. Mitochondrial sequence data did not support the existence of the two currently accepted subspecies. Furthermore, analyses of the microsatellite data with a Bayesian clustering method did not support the existence of two source populations as it would be expected under the mountain refugia scenario. Our findings suggest that phenotypic plasticity rather than distinct ancestry is the leading cause behind the phenotypic divergence observed between montane forest and savanna honey bees. Our study thus corroborates the idea that high gene flow may select for increased plasticity.

  1. Reassessment of source parameters for three major earthquakes in the East African rift system from historical seismograms and bulletins

    Directory of Open Access Journals (Sweden)

    O. Kulhánek

    2000-06-01

    Full Text Available Source parameters for three majo earthquakes in the East African rift are re-computed from historical seismograms and bulletins. The main shock and the largest foreshock of the August 25, 1906 earthquake sequence in the main Ethiopian rift are re-located on the eastern shoulder of the rift segment.The magnitude of the main shock is estimated to be 6.5 (Mw from spectral analysis. The December 13, 1910 earthquake in the Rukwa rift (Western Tanzania indicated a significant strike-slip component from teleseismcs body-waveform inversion for fault mechanism and seismic moment. The January 6, 1928 earthquake in the Gregory rift (Kenya showed a multiple rupture process and unusually long duration for a size of 6.6(Mw. The May 20, 1990 earthquake in Southern Sudan, mentioned merely for the sake of comparison, is the largest of all instrumentally recorded events in the East African rift system. Despite the fact that the mode of deformation in the continental rift is predominantly of extensional nature, the three largest earthquakes known to occur in the circum-Tanzanian craton have shallow focal depths and significant strike-slip component in their fault mechanisms. This and similar works will enrich the database for seismic hazard assessment in East Africa.

  2. Herbivore removal reduces influence of arbuscular mycorrhizal fungi on plant growth and tolerance in an East African savanna.

    Science.gov (United States)

    González, Jonathan B; Petipas, Renee H; Franken, Oscar; Kiers, E Toby; Veblen, Kari E; Brody, Alison K

    2018-05-01

    The functional relationship between arbuscular mycorrhizal fungi (AMF) and their hosts is variable on small spatial scales. Here, we hypothesized that herbivore exclusion changes the AMF community and alters the ability of AMF to enhance plant tolerance to grazing. We grew the perennial bunchgrass, Themeda triandra Forssk in inoculum from soils collected in the Kenya Long-term Exclosure Experiment where treatments representing different levels of herbivory have been in place since 1995. We assessed AMF diversity in the field, using terminal restriction fragment length polymorphism and compared fungal diversity among treatments. We conducted clipping experiments in the greenhouse and field and assessed regrowth. Plants inoculated with AMF from areas accessed by wild herbivores and cattle had greater biomass than non-inoculated controls, while plants inoculated with AMF from where large herbivores were excluded did not benefit from AMF in terms of biomass production. However, only the inoculation with AMF from areas with wild herbivores and no cattle had a positive effect on regrowth, relative to clipped plants grown without AMF. Similarly, in the field, regrowth of plants after clipping in areas with only native herbivores was higher than other treatments. Functional differences in AMF were evident despite little difference in AMF species richness or community composition. Our findings suggest that differences in large herbivore communities over nearly two decades has resulted in localized, functional changes in AMF communities. Our results add to the accumulating evidence that mycorrhizae are locally adapted and that functional differences can evolve within small geographical areas.

  3. INSIDE THE NUMBERS: USING PRIVATE COMMERCIAL DATA TO ANALYZE EAST AFRICAN IMPORTED SOAP CONSUMPTION, 1870-1914

    Directory of Open Access Journals (Sweden)

    Laird Jones

    2015-06-01

    Full Text Available Social historians identify soap as a “new need,” and argue its consumption indicates changing notions of bodily cleanliness, beauty and status. Relying largely on qualitative evidence such as traveler and missionary accounts, print advertising and oral interviews, they contend African soap use was influenced by Christian missions, colonial education and branding in the marketplace. Quantitative evidence – limited customs data – neither confirms nor challenges this position. More detailed commercial records, however, paint a somewhat different picture. The East African correspondence of William O’Swald & Co. indicates that soap marketing predated both Christian missions and colonial influence. Further, general purpose laundry soap was the overwhelming best seller. Personal toilette soaps lagged far behind. Laundering imported cotton textiles appeared the motive for initial soap purchases, and perhaps also the first step toward later personal soap use.

  4. Ages of tuff beds at East African early hominid sites and sediments in the Gulf of Aden

    Science.gov (United States)

    Sarna-Wojcicki, A. M.; Meyer, C.E.; Roth, P.H.; Brown, F.H.

    1985-01-01

    The early hominids of East Africa were dated by determining the ages of tuff beds at the sites. Despite much research using palaeomagnetic and K/Ar-dating techniques, some of those ages are still controversial 1,2. To obtain independent age estimates for these tephra layers, we have examined cores from DSDP Sites 231 and 232 in the Gulf of Aden (Fig. 1a) which consist mainly of calcareous nannofossil ooze, but also contain rare tephra horizons3 dated by interpolation from the established nannofossil stratigraphy (Fig. 1b). Chemical analysis confirms that the identity and sequence of these horizons is the same as that at the East African sites. We conclude that the age of the Tulu Bor Tuff is <3.4 Myr and hence that the Hadar hominid specimens are also

  5. Reassessment of source parameters for three major earthquakes in the East African rift system from historical seismograms and bulletins

    OpenAIRE

    Ayele, A.; Kulhánek, O.

    2000-01-01

    Source parameters for three majo earthquakes in the East African rift are re-computed from historical seismograms and bulletins. The main shock and the largest foreshock of the August 25, 1906 earthquake sequence in the main Ethiopian rift are re-located on the eastern shoulder of the rift segment.The magnitude of the main shock is estimated to be 6.5 (Mw) from spectral analysis. The December 13, 1910 earthquake in the Rukwa rift (Western Tanzania) indicated a significant strike-slip componen...

  6. The strange case of East African annual fishes: aridification correlates with diversification for a savannah aquatic group?

    Science.gov (United States)

    Dorn, Alexander; Musilová, Zuzana; Platzer, Matthias; Reichwald, Kathrin; Cellerino, Alessandro

    2014-10-14

    Annual Nothobranchius fishes are distributed in East and Southern Africa and inhabit ephemeral pools filled during the monsoon season. Nothobranchius show extreme life-history adaptations: embryos survive by entering diapause and they are the vertebrates with the fastest maturation and the shortest lifespan. The distribution of Nothobranchius overlaps with the East Africa Rift System. The geological and paleoclimatic history of this region is known in detail: in particular, aridification of East Africa and expansion of grassland habitats started 8 Mya and three humid periods between 3 and 1 Mya are superimposed on the longer-term aridification. These climatic oscillations are thought to have shaped evolution of savannah African mammals. We reconstructed the phylogeny of Nothobranchius and dated the different stages of diversification in relation to these paleoclimatic events. We sequenced one mitochondrial locus and five nuclear loci in 63 specimens and obtained a robust phylogeny. Nothobranchius can be divided in four geographically separated clades whose boundaries largely correspond to the East Africa Rift system. Statistical analysis of dispersal and vicariance identifies a Nilo-Sudan origin with southwards dispersion and confirmed that these four clades are the result of vicariance events In the absence of fossil Nothobranchius, molecular clock was calibrated using more distant outgroups (secondary calibration). This method estimates the age of the Nothobranchius genus to be 8.3 (6.0 - 10.7) My and the separation of the four clades 4.8 (2.7-7.0) Mya. Diversification within the clades was estimated to have started ~3 Mya and most species pairs were estimated to have an age of 0.5-1 My. The mechanism of Nothobranchius diversification was allopatric and driven by geographic isolation. We propose a scenario where diversification of Nothobranchius started in rough coincidence with aridification of East Africa, establishment of grassland habitats and the appearance

  7. Xenoliths from Bunyaruguru volcanic field: Some insights into lithology of East African Rift upper mantle

    Science.gov (United States)

    Muravyeva, N. S.; Senin, V. G.

    2018-01-01

    The mineral composition of mantle xenoliths from kamafugites of the Bunyaruguru volcanic field has been determined. The major and some trace elements (Si, Ti, Al, Fe, Mn, Mg, Ca, Na, K, Cr, Ni, Ba, Sr, La, Ce, Nd, Nb) has been analyzed in olivine, clinopyroxene, phlogopite, Cr-spinel, titanomagnetite, perovskite and carbonates of xenoliths and their host lavas. Bunyaruguru is one of three (Katwe-Kikorongo, Fort Portal and Bunyaruguru) volcanic fields included in the Toro-Ankole province located on the North end of the West Branch of the East African Rift. The xenoliths from three craters within the Bunyaruguru volcanic field revealed the different character of metasomatic alteration, reflecting the heterogeneity of the mantle on the kilometer scale. The most unusual finding was composite glimmerite-wehrlite xenolith from the crater Kazimiro, which contains the fresh primary high-Mg olivine with inclusions of Cr-spinel that had not been previously identified in this area. The different composition of phenocryst and xenolith minerals indicates that the studied xenoliths are not cumulus of enclosing magma, but the composition of xenoliths characterizes the lithology of the upper mantle of the area. The carbonate melt inclusions in olivine Fo90 demonstrate the existence of primary carbonatitic magmas in Bunyaruguru upper mantle. The results of texture and chemical investigation of the xenolith minerals indicate the time sequence of metasomatic alteration of Bunyaruguru upper mantle: MARID metasomatism at the first stage followed by carbonate metasomatism. The abundances of REE in perovskites from kamafugite are 2-4 times higher than similar values for xenolith. Therefore the kamafugite magma was been generated from a more enriched mantle source than the source of the xenoliths. The evaluation of P-T conditions formation of clinopyroxene xenolith revealed the range of pressure 20-65 kbar and the temperatures range 830-1040 °C. The pressure of clinopyroxene phenocryst

  8. Contrasted continental rifting via plume-craton interaction: Applications to Central East African Rift

    Directory of Open Access Journals (Sweden)

    Alexander Koptev

    2016-03-01

    Full Text Available The East African Rift system (EARS provides a unique system with the juxtaposition of two contrasting yet simultaneously formed rift branches, the eastern, magma-rich, and the western, magma-poor, on either sides of the old thick Tanzanian craton embedded in a younger lithosphere. Data on the pre-rift, syn-rift and post-rift far-field volcanic and tectonic activity show that the EARS formed in the context of the interaction between a deep mantle plume and a horizontally and vertically heterogeneous lithosphere under far-field tectonic extension. We bring quantitative insights into this evolution by implementing high-resolution 3D thermo-mechanical numerical deformation models of a lithosphere of realistic rheology. The models focus on the central part of the EARS. We explore scenarios of plume-lithosphere interaction with plumes of various size and initial position rising beneath a tectonically pre-stretched lithosphere. We test the impact of the inherited rheological discontinuities (suture zones along the craton borders, of the rheological structure, of lithosphere plate thickness variations, and of physical and mechanical contrasts between the craton and the embedding lithosphere. Our experiments indicate that the ascending plume material is deflected by the cratonic keel and preferentially channeled along one of its sides, leading to the formation of a large rift zone along the eastern side of the craton, with significant magmatic activity and substantial melt amount derived from the mantle plume material. We show that the observed asymmetry of the central EARS, with coeval amagmatic (western and magmatic (eastern branches, can be explained by the splitting of warm material rising from a broad plume head whose initial position is slightly shifted to the eastern side of the craton. In that case, neither a mechanical weakness of the contact between the craton and the embedding lithosphere nor the presence of second plume are required to

  9. 3D Numerical Rift Modeling with Application to the East African Rift System

    Science.gov (United States)

    Glerum, A.; Brune, S.; Naliboff, J.

    2017-12-01

    As key components of plate tectonics, continental rifting and the formation of passive margins have been extensively studied with both analogue models and numerical techniques. Only recently however, technical advances have enabled numerical investigations into rift evolution in three dimensions, as is actually required for including those processes that cause rift-parallel variability, such as structural inheritance and oblique extension (Brune 2016). We use the massively parallel finite element code ASPECT (Kronbichler et al. 2012; Heister et al. 2017) to investigate rift evolution. ASPECT's adaptive mesh refinement enables us to focus resolution on the regions of interest (i.e. the rift center), while leaving other areas such as the asthenospheric mantle at coarse resolution, leading to kilometer-scale local mesh resolution in 3D. Furthermore, we implemented plastic and viscous strain weakening of the nonlinear viscoplastic rheology required to develop asymmetric rift geometries (e.g. Huismans and Beaumont 2003). Additionally created plugins to ASPECT allow us to specify initial temperature and composition conditions based on geophysical data (e.g. LITHO1.0, Pasyanos et al. 2014) or to prescribe more general along-strike variation in the initial strain seeding the rift. Employing the above functionality, we construct regional models of the East African Rift System (EARS), the world's largest currently active rift. As the EARS is characterized by both orthogonal and oblique rift sections, multi-phase extension histories as well as magmatic and a-magmatic branches (e.g. Chorowicz 2005; Ebinger and Scholz 2011), it constitutes an extensive natural laboratory for our research into the 3D nature of continental rifting. References:Brune, S. (2016), in Plate boundaries and natural hazards, AGU Geophysical Monograph 219, J. C. Duarte and W. P. Schellart (Eds.). Chorowicz, J. (2005). J. Afr. Earth Sci., 43, 379-410. Ebinger, C. and Scholz, C. A. (2011), in Tectonics of

  10. Rayleigh Wave Phase Velocities Beneath the Central and Southern East African Rift System

    Science.gov (United States)

    Adams, A. N.; Miller, J. C.

    2017-12-01

    This study uses the Automated Generalized Seismological Data Function (AGSDF) method to develop a model of Rayleigh wave phase velocities in the central and southern portions of the East African Rift System (EARS). These phase velocity models at periods of 20-100s lend insight into the lithospheric structures associated with surficial rifting and volcanism, as well as basement structures that pre-date and affect the course of rifting. A large dataset of >700 earthquakes is used, comprised of Mw=6.0+ events that occurred between the years 1995 and 2016. These events were recorded by a composite array of 176 stations from twelve non-contemporaneous seismic networks, each with a distinctive array geometry and station spacing. Several first-order features are resolved in this phase velocity model, confirming findings from previous studies. (1) Low velocities are observed in isolated regions along the Western Rift Branch and across the Eastern Rift Branch, corresponding to areas of active volcanism. (2) Two linear low velocity zones are imaged trending southeast and southwest from the Eastern Rift Branch in Tanzania, corresponding with areas of seismic activity and indicating possible incipient rifting. (3) High velocity regions are observed beneath both the Tanzania Craton and the Bangweulu Block. Furthermore, this model indicates several new findings. (1) High velocities beneath the Bangweulu Block extend to longer periods than those found beneath the Tanzania Craton, perhaps indicating that rifting processes have not altered the Bangweulu Block as extensively as the Tanzania Craton. (2) At long periods, the fast velocities beneath the Bangweulu Block extend eastwards beyond the surficial boundaries, to and possibly across the Malawi Rift. This may suggest the presence of older, thick blocks of lithosphere in regions where they are not exposed at the surface. (3) Finally, while the findings of this study correspond well with previous studies in regions of overlapping

  11. Historical volcanism and the state of stress in the East African Rift System

    Directory of Open Access Journals (Sweden)

    Geoffrey Wadge

    2016-09-01

    Full Text Available Crustal extension at the East African Rift System (EARS should, as a tectonic ideal, involve a stress field in which the direction of minimum horizontal stress is perpendicular to the rift. A volcano in such a setting should produce dykes and fissures parallel to the rift. How closely do the volcanoes of the EARS follow this? We answer this question by studying the 21 volcanoes that have erupted historically (since about 1800 and find that 7 match the (approximate geometrical ideal. At the other 14 volcanoes the orientation of the eruptive fissures/dykes and/or the axes of the host rift segments are oblique to the ideal values. To explain the eruptions at these volcanoes we invoke local (non-plate tectonic variations of the stress field caused by: crustal heterogeneities and anisotropies (dominated by NW structures in the Protoerozoic basement, transfer zone tectonics at the ends of offset rift segments, gravitational loading by the volcanic edifice (typically those with 1-2 km relief and magmatic pressure in central reservoirs. We find that the more oblique volcanoes tend to have large edifices, large eruptive volumes and evolved and mixed magmas capable of explosive behaviour. Nine of the volcanoes have calderas of varying ellipticity, 6 of which are large, reservoir-collapse types mainly elongated across rift (e.g. Kone and 3 are smaller, elongated parallel to the rift and contain active lava lakes (e.g. Erta Ale, suggesting different mechanisms of formation and stress fields. Nyamuragira is the only EARS volcano with enough sufficiently well-documented eruptions to infer its long-term dynamic behaviour. Eruptions within 7 km of the volcano are of relatively short duration (<100 days, but eruptions with more distal fissures tend to have greater obliquity and longer durations, indicating a changing stress field away from the volcano. There were major changes in long-term magma extrusion rates in 1977 (and perhaps in 2002 due to major along

  12. Constraints to estimating the prevalence of trypanosome infections in East African zebu cattle

    Directory of Open Access Journals (Sweden)

    Cox Andrew P

    2010-09-01

    Full Text Available Abstract Background In East Africa, animal trypanosomiasis is caused by many tsetse transmitted protozoan parasites including Trypanosoma vivax, T. congolense and subspecies of T. brucei s.l. (T. b. brucei and zoonotic human infective T. b. rhodesiense that may co-circulate in domestic and wild animals. Accurate species-specific prevalence measurements of these parasites in animal populations are complicated by mixed infections of trypanosomes within individual hosts, low parasite densities and difficulties in conducting field studies. Many Polymerase Chain Reaction (PCR based diagnostic tools are available to characterise and quantify infection in animals. These are important for assessing the contribution of infections in animal reservoirs and the risk posed to humans from zoonotic trypanosome species. New matrices for DNA capture have simplified large scale field PCR analyses but few studies have examined the impact of these techniques on prevalence estimations. Results The Whatman FTA matrix has been evaluated using a random sample of 35 village zebu cattle from a population naturally exposed to trypanosome infection. Using a generic trypanosome-specific PCR, prevalence was systematically evaluated. Multiple PCR samples taken from single FTA cards demonstrated that a single punch from an FTA card is not sufficient to confirm the infectivity status of an individual animal as parasite DNA is unevenly distributed across the card. At low parasite densities in the host, this stochastic sampling effect results in underestimation of prevalence based on single punch PCR testing. Repeated testing increased the estimated prevalence of all Trypanosoma spp. from 9.7% to 86%. Using repeat testing, a very high prevalence of pathogenic trypanosomes was detected in these local village cattle: T. brucei (34.3%, T. congolense (42.9% and T. vivax (22.9%. Conclusions These results show that, despite the convenience of Whatman FTA cards and specific PCR based

  13. Constraints to estimating the prevalence of trypanosome infections in East African zebu cattle.

    Science.gov (United States)

    Cox, Andrew P; Tosas, Olga; Tilley, Aimee; Picozzi, Kim; Coleman, Paul; Hide, Geoff; Welburn, Susan C

    2010-09-06

    In East Africa, animal trypanosomiasis is caused by many tsetse transmitted protozoan parasites including Trypanosoma vivax, T. congolense and subspecies of T. brucei s.l. (T. b. brucei and zoonotic human infective T. b. rhodesiense) that may co-circulate in domestic and wild animals. Accurate species-specific prevalence measurements of these parasites in animal populations are complicated by mixed infections of trypanosomes within individual hosts, low parasite densities and difficulties in conducting field studies. Many Polymerase Chain Reaction (PCR) based diagnostic tools are available to characterise and quantify infection in animals. These are important for assessing the contribution of infections in animal reservoirs and the risk posed to humans from zoonotic trypanosome species. New matrices for DNA capture have simplified large scale field PCR analyses but few studies have examined the impact of these techniques on prevalence estimations. The Whatman FTA matrix has been evaluated using a random sample of 35 village zebu cattle from a population naturally exposed to trypanosome infection. Using a generic trypanosome-specific PCR, prevalence was systematically evaluated. Multiple PCR samples taken from single FTA cards demonstrated that a single punch from an FTA card is not sufficient to confirm the infectivity status of an individual animal as parasite DNA is unevenly distributed across the card. At low parasite densities in the host, this stochastic sampling effect results in underestimation of prevalence based on single punch PCR testing. Repeated testing increased the estimated prevalence of all Trypanosoma spp. from 9.7% to 86%. Using repeat testing, a very high prevalence of pathogenic trypanosomes was detected in these local village cattle: T. brucei (34.3%), T. congolense (42.9%) and T. vivax (22.9%). These results show that, despite the convenience of Whatman FTA cards and specific PCR based detection tools, the chronically low parasitaemias in

  14. Deciphering the distribution of the savanna biome

    CSIR Research Space (South Africa)

    Lehmann, CER

    2011-07-01

    Full Text Available to rainfall. We identified three continental divergences in the limits of savanna that could not be explained by environment. Climate and soils do not have a deterministic effect on the distribution of savanna. Over the range of savanna, some proportion...

  15. Tropical savannas and dry forests.

    Science.gov (United States)

    Pennington, R Toby; Lehmann, Caroline E R; Rowland, Lucy M

    2018-05-07

    In the tropics, research, conservation and public attention focus on rain forests, but this neglects that half of the global tropics have a seasonally dry climate. These regions are home to dry forests and savannas (Figures 1 and 2), and are the focus of this Primer. The attention given to rain forests is understandable. Their high species diversity, sheer stature and luxuriance thrill biologists today as much as they did the first explorers in the Age of Discovery. Although dry forest and savanna may make less of a first impression, they support a fascinating diversity of plant strategies to cope with stress and disturbance including fire, drought and herbivory. Savannas played a fundamental role in human evolution, and across Africa and India they support iconic megafauna. Copyright © 2018 Elsevier Ltd. All rights reserved.

  16. Isotopic signature of Pan-African rejuvenation in the Kerala Khondalite belt, southern India: implications for east Gondwana reassembly

    International Nuclear Information System (INIS)

    Unnikrishnan Warrier, C.

    1997-01-01

    Sm-Nd isotope systematics on mineral separates from sillimanite-and cordierite-bearing metapelite (khondalite), and garnet-and biotite-bearing gneiss (leptynite) from the Kerala Khondalite Belt (KKB), southern India, yielded mineral isochron ages (wr-feld-bio-gar) of 537±27 Ma (MSWD=0.9) and 534±26 Ma (MSWD=1.23) respectively. Rb-Sr systematics in the same samples gave wr-feld-bio mineral isochron ages of 437±9 Ma (MSWD=0.67) and 467±9 Ma (MSWD=0.76). These results provide the first mineral isochron ages for the regional metasedimentaries in the KKB. The ε (Nd T) values at 550 Ma for khondalite and leptynite are -22.7 and -21.8 respectively. These results demonstrate a complete rejuvenation of the crust during Pan-African times. Coeval alkaline plutons emplaced along fault-lineaments in this area suggest an extensional tectonic regime. Geochronologic correlations with the Lutzow-Holm bay complexes in east Antarctica, and the highland and southwestern complex of Sri Lanka show that a similar Pan-African tectono-thermal event manifested in all the east Gondwana crustal fragments. (author)

  17. Genetic diversity of the Mycobacterium tuberculosis East African–Indian family in three tropical Asian countries

    Directory of Open Access Journals (Sweden)

    Yih-Yuan Chen

    2017-12-01

    Full Text Available Background: The Beijing lineage of Mycobacterium tuberculosis (MTB is the most predominant MTB strain in Asian countries and is spreading worldwide, however, the East African–Indian (EAI lineage is also particularly prevalent in many tropical Asian countries. The evolutionary relationships among MTB EAI isolates from Taiwan and those of tropical Asian countries remain unknown. Methods: The EAI strains collected from patients in Taiwan were analyzed using spacer oligonucleotide typing and mycobacterial interspersed repetitive unit–variable number of tandem repeats (MIRU-VNTR typing, and compared with published profiles from Cambodia and Singapore to investigate potential epidemiological linkages. Results: Among the three countries, the EAI lineage was most prevalent in Cambodia (60%; Singapore, 25.62%; and Taiwan, 21.85%, having also the highest rates of multidrug resistance and lowest rates of clustering of MTB isolates. We describe a convenient method using seven selected MIRU-VNTR loci for first-line typing to discriminate Beijing and EAI lineages. A potential epidemiological linkage in these tropical Asian countries is also discussed based on a minimum-spanning tree constructed using 24 MIRU-VNTR loci of MTB EAI strains. Conclusion: This study identified evolutionary relationships among MTB EAI isolates from Taiwan and those of two other tropical Asian countries, Cambodia and Singapore. Keywords: East African–Indian family, Mycobacterium tuberculosis, tropical Asian countries

  18. Farming Systems of the African Savanna

    International Development Research Centre (IDRC) Digital Library (Canada)

    It is impossible to thank all those farmers, researchers, and others who have ..... Farmers using this method aim to maintain or even increase the OM content of the soil by ... (Some types of fertilizer may damage the seed or young plants if placed in ..... The structure of a system is defined by the quantitative and qualitative ...

  19. Differential decay of the East-African Antarctic Orogen : an integrated examination of Northeastern Mozambique

    Science.gov (United States)

    Ueda, K.; Jacobs, J.; Emmel, B.; Thomas, R. J.; Matola, R.

    2009-04-01

    In Northeastern Mozambique, the late Proterozoic - early Paleozoic East African-Antarctic Orogen can be subdivided into two major blocks that exhibit some relevant differences. The line of divide is represented by the Lurio Belt, a kinematically poorly constrained shear zone that also marks the conceptual northern limit of frequent late-tectonic granitoid intrusions. Moreover, far-travelled granulite-facies nappes cover a much larger area north of this belt (Viola et. al, 2008), giving rise to the assumption of different exhumation and present exposure levels. U/Pb data from previous surveys (e.g., Norconsult consortium, 2007) show coeval high-grade metamorphism in the whole region between c. 610 - 550 Ma, while the block south of the Lurio Belt also shows continuing metamorphism until c. 490 Ma that can be related to extension. Geothermobarometry for samples from within the Lurio Belt (Engvik et. al, 2007) indicates rapid exhumation after high-pressure granulite facies metamorphism and is consistant with the assumption of long tectonic activity. A possible model for the outlined pattern is the delamination of the orogenic root only in the southern part, followed by rapid mechanical thinning as well as by isostatic accommodation along the Lurio Belt. A valuable marker was identified in the metasedimentary Mecuburi group that overlies the southern basement. U/Pb analysis of detrital zircons have yielded a maximum deposition age of c. 600 Ma, while metamorphism is recorded until c. 505 Ma. Investigations of the relationship between metasediments and older basement show that the basal contact is a fairly preserved depositional contact, allowing to suppose a conjoint post-depositional evolution. It is notable that the timing of deposition shortly follows the onset of the main, widespread high-grade metamorphism. Relatively high but variable degrees of migmatisation in the Mecuburi Group require a phase of burial from surface to deep levels after 600 Ma, followed by

  20. A Comparative Analysis of Institutional Capacities for Implementing Disability Policies in East African Countries: Functions of National Councils for Disability

    Directory of Open Access Journals (Sweden)

    Akiko Yokoyama

    2012-08-01

    Full Text Available During the “African Decade of Persons with Disabilities (2000-2009”, East African countries witnessed significant achievements, especially in the development of law, collection of statistics and in funding. However, many persons with disability are still marginalised from opportunities in education, healthcare and employment.Purpose: With the pre-supposition that the lack of institutional capacities for implementing disability policies is the one major stumbling-block which hinders widespread delivery of social services to persons with disabilities in low-income countries, this study makes a comparative analysis of institutional capacities in the disability sectors of Uganda, Kenya and Tanzania.Method: The research methods adopted were a literature survey and a field survey. The framework for analysis consists of: 1 capacities and functions of disability units in central governments, 2 relationships between central and local governments in the disability sector, and 3 relationships between governments and organisations of persons with disability (DPOs. Special attention is paid to the status, roles and functions of national councils for disability (NCDs, the independent statutory bodies recently established in each of the three countries, with clear authority and duties for the implementation of disability policies. The NCDs enable multi-sectoral stakeholders to be involved in the implementation of disability policies; therefore, positive relationships between the governments and DPOs are essential for the smooth functioning of the NCDs.Results: While the result of the field survey in Tanzania reveals several effective approaches for the smooth operation of the NCD, further study is needed to verify whether these approaches would be applicable to other East African countries such as Kenya and Uganda.doi 10.5463/DCID.v23i2.106

  1. The Ngorongoro Volcanic Highland and its relationships to volcanic deposits at Olduvai Gorge and East African Rift volcanism.

    Science.gov (United States)

    Mollel, Godwin F; Swisher, Carl C

    2012-08-01

    The Ngorongoro Volcanic Highland (NVH), situated adjacent and to the east of Olduvai Gorge in northern Tanzania, is the source of the immense quantities of lava, ignimbrite, air fall ash, and volcaniclastic debris that occur interbedded in the Plio-Pleistocene sedimentary deposits in the Laetoli and Olduvai areas. These volcanics have proven crucial to unraveling stratigraphic correlations, the age of these successions, the archaeological and paleontological remains, as well as the source materials from which the bulk of the stone tools were manufactured. The NVH towers some 2,000 m above the Olduvai and Laetoli landscapes, affecting local climate, run-off, and providing varying elevation - climate controlled ecosystem, habitats, and riparian corridors extending into the Olduvai and Laetoli lowlands. The NVH also plays a crucial role in addressing the genesis and history of East African Rift (EAR) magmatism in northern Tanzania. In this contribution, we provide age and petrochemical compositions of the major NVH centers: Lemagurut, basalt to benmorite, 2.4-2.2 Ma; Satiman, tephrite to phonolite, 4.6-3.5 Ma; Oldeani, basalt to trachyandesite, 1.6-1.5 Ma; Ngorongoro, basalt to rhyolite, 2.3-2.0 Ma; Olmoti, basalt to trachyte, 2.0-1.8 Ma; Embagai, nephelinite to phonolite, 1.2-0.6 Ma; and Engelosin, phonolite, 3-2.7 Ma. We then discuss how these correlate in time and composition with volcanics preserved at Olduvai Gorge. Finally, we place this into context with our current understanding as to the eruptive history of the NVH and relationship to East African Rift volcanism. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. Analysis of the genetic diversity of selected East African sweet potato

    African Journals Online (AJOL)

    Aghomotsegin

    Taiwan. Orange. 65. Mugande x New kawogo 2. Uganda. Cream. 66. Bungoma. Uganda .... African countries is still very slow due to financial and technical .... IPGRI, Rome,. Italy and Institute for Genetic Diversity, Ithaca, New York, USA. ISBN:.

  3. East and Central African Journal of Surgery http://www.bioline.org.br ...

    African Journals Online (AJOL)

    Patrick

    populations in Asia, far-east, and North America. By far reported cases ... Zomba Central hospital with long standing history of a giant scalp cutenous horn for about 28 years .Excision ... educative pathologies goes under reported. Case Report.

  4. Quantification of African cassava mosaic virus (ACMV) and East African cassava mosaic virus (EACMV-UG) in single and mixed infected Cassava (Manihot esculenta Crantz) using quantitative PCR.

    Science.gov (United States)

    Naseem, Saadia; Winter, Stephan

    2016-01-01

    The quantity of genomic DNA-A and DNA-B of African cassava mosaic virus (ACMV) and East African cassava mosaic virus Uganda (Uganda variant, EACMV-UG) was analysed using quantitative PCR to assess virus concentrations in plants from susceptible and tolerant cultivars. The concentrations of genome components in absolute and relative quantification experiments in single and mixed viral infections were determined. Virus concentration was much higher in symptomatic leaf tissues compared to non-symptomatic leaves and corresponded with the severity of disease symptoms. In general, higher titres were recorded for EACMV-UG Ca055 compared to ACMV DRC6. The quantitative assessment also showed that the distribution of both viruses in the moderately resistant cassava cv. TMS 30572 was not different from the highly susceptible cv. TME 117. Natural mixed infections with both viruses gave severe disease symptoms. Relative quantification of virus genomes in mixed infections showed higher concentrations of EACMV-UG DNA-A compared to ACMV DNA-A, but a marked reduction of EACMV-UG DNA-B. The higher concentrations of EACMV-UG DNA-B compared to EACMV DNA-A accumulation in single infections were consistent. Since DNA-B is implicated in virus cell-to-cell spread and systemic movement, the abundance of the EACMV-UG DNA-B may be an important factor driving cassava mosaic disease epidemic. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Multiple endmember spectral-angle-mapper (SAM) analysis improves discrimination of Savanna tree species

    CSIR Research Space (South Africa)

    Cho, Moses A

    2009-08-01

    Full Text Available of this paper was to evaluate the classification performance of a multiple-endmember spectral angle mapper (SAM) classification approach in discriminating seven common African savanna tree species and to compare the results with the traditional SAM classifier...

  6. Interacting effects of grass height and herbivores on the establishment of an encroaching savanna shrub

    NARCIS (Netherlands)

    Hagenah, N.; Munkert, H.; Gerhardt, K.; Olff, H.

    2009-01-01

    Shrub encroachment is a widely observed problem in Southern African savannas. Although the effects of herbivory and grass height on woody species recruitment have been studied individually, little information exists about how these factors interact. In this study seeds and seedlings of the

  7. Synthesis of field experiments concerning the grass layer in the savanna regions of southern Africa

    CSIR Research Space (South Africa)

    O'Connor, TG

    1985-10-01

    Full Text Available The purpose of this synthesis of long term experiments was to develop an account of how the principal determinants (rainfall, soil type, woody/grass ratio, herbivory, fire) influence the dynamics of the grass layer of southern African savannas...

  8. Dry season mapping of savanna forage quality, using the hyperspectral Carnegie

    NARCIS (Netherlands)

    Knox, N.; Skidmore, A.K.; Prins, H.H.T.; Asner, P.; Werff, van der H.M.A.; Boer, de W.F.; Waal, van der C.; Knegt, de H.J.; Kohi, E.; Slotow, R.; Grant, R.C.

    2011-01-01

    Forage quality within an African savanna depends upon limiting nutrients (nitrogen and phosphorus) and nutrients that constrain the intake rates (non-digestible fibre) of herbivores. These forage quality nutrients are particularly crucial in the dry season when concentrations of limiting nutrients

  9. Unlocking resources in savannas: how goats and other mixed feeders overcome the negative effects of tannins

    NARCIS (Netherlands)

    Mkhize, N.R.

    2015-01-01

    Abstract

    This thesis contributes insights on how condensed tannins might mediate the interactions between woody plants and large herbivores in the African savannas. Current understanding in this regard is still based on data from short-term laboratory experiments, mostly

  10. Elephant distribution around a volcanic shield dominated by a mosaic of forest and savanna (Marsabit, Kenya)

    NARCIS (Netherlands)

    Ngene, S.M.; Skidmore, A.K.; Gils, H.; Douglas-Hamilton, I.; Omondi, P.

    2009-01-01

    We investigated the factors that influenced the distribution of the African elephant around a volcanic shield dominated by a mosaic of forest and savanna in northern Kenya. Data on elephant distribution were acquired from four female and five bull elephants, collared with satellite-linked

  11. Water-removed spectra increase the retrieval accuracy when estimating savanna grass nitrogen and phosphorus concentrations

    CSIR Research Space (South Africa)

    Ramoelo, Abel

    2011-01-01

    Full Text Available . Ritchie and H. H. T. Prins (2002). Global enviromental controls of diversity of large hervivores. Nature 415: 901-904. 26 Owen-Smith, N. and S. M. Cooper (1987). Palatabilty of woody plants to browsing ruminants in a South African savanna. In...

  12. Non-uniform splitting of a single mantle plume by double cratonic roots : Insight into the origin of the central and southern East African Rift System

    NARCIS (Netherlands)

    Koptev, Alexander; Cloetingh, Sierd; Gerya, Taras; Calais, Eric; Leroy, Sylvie

    Using numerical thermo-mechanical experiments we analyse the role of an active mantle plume and pre-existing lithospheric thickness differences in the structural development of the central and southern East African Rift system. The plume-lithosphere interaction model setup captures the essential

  13. Tiger, tiger, burning bright? industrial policy lessons from Ireland and East Asia for small African economies

    OpenAIRE

    Bailey, David; Lenihan, Helena; Singh, Ajit

    2008-01-01

    The African economies, particularly those in Sub-Saharan Africa (SSA) stand today at an important crossroads. During the 1980s, for the average African country, GDP per capita fell at a rate of 0.5 percent per annum; in the 1990s it rose slightly at a rate of 0.3 percent per annum. However, in the last four years, the average growth rate of this variable has been a respectable 3 percent per annum. In 2007, GDP growth rate in Africa was estimated to be 6 percent per annum, one of the highest r...

  14. Impact of savanna conversion to oil palm plantations on C stocks dynamics and soil fertility

    Science.gov (United States)

    Quezada, Juan Carlos; Guillaume, Thomas; Buttler, Alexandre; Ruegg, Johanna

    2017-04-01

    Large-scale expansion of oil palm cultivation on forested land in South-East Asia during the last decades lead to high negative environmental impacts. Because rainforests store high amount of C, their conversion to oil palm plantations results in large net CO2 emissions. Oil palm cultivation in tropical ecosystems such as savanna that store less C than forests is seen as an alternative to reduce greenhouse gas emissions of future oil palm development. While this option is more and more frequently mentioned, few data are available on the effective gain in C storage. Furthermore negative impact on soil organic carbon and soil fertility could offset gains of C storage in oil palm biomass. Here, we present results on aboveground and belowground C stocks and soil nutrient dynamics over a full rotation cycle of oil palm plantations established on tropical savanna grasslands. Three natural savanna grasslands as reference sites and 9 oil palm plantations ranging from two to twenty-seven years old were selected in the Llanos in Colombia. Oxisols were sampled down to 70 cm in each management zones of oil palm plantations (weeded circle, interrow, frond piles and harvesting path). Taking advantages of a shift from C4 to C3 vegetation, we quantified savanna-derived soil organic carbon (SOC) decomposition and oil palm-derived SOC stabilization rates and how they were affected by management practices (mineral fertilization, organic amendments, etc.). Results show that, in opposite to forest conversion, C storage increases when savannas are converted to oil palm plantations. Because soil C storage was very low in natural conditions, SOC changes had little effects on overall C storage. Substitution of savanna-derived SOC by oil palm-derived SOC was very fast in the topsoil and highest under frond pile and weeded circle where C and nutrients inputs are highest. However, stabilization of oil palm-derived SOC compensated loss of savanna-derived SOC rather than increased SOC stocks

  15. Teachers’ Perceptions on the Use of African Languages in the Curriculum: A Case Study of Schools in Kenya, East Africa

    Directory of Open Access Journals (Sweden)

    Martin C. Njoroge

    2011-08-01

    Full Text Available In order to revitalize African languages and advocate for their use as media of instruction in Kenyan schools, it is important to investigate and document the teachers’ attitude towards the use of these languages in teaching. The research on which this paper is based set forth to explore teachers’ perceptions on the use of the mother tongue as the language of instruction in Kenya, East Africa. Six schools out of 54 public schools in the Gatundu district were randomly sampled. 32 teachers of Grades 1-3 were interviewed to find out the actual practices in their classrooms, the challenges they faced, and the perceptions they held in relation to the use of the mother tongue in their teaching. The data were qualitatively analyzed and the emergent findings support the claim that the use of learners’ mother tongue is beneficial to learners. In addition, the paper discusses the findings and proposes recommendations for pedagogy.

  16. Fuel biomass and combustion factors associated with fires in savanna ecosystems of South Africa and Zambia

    Science.gov (United States)

    Shea, Ronald W.; Shea, Barbara W.; Kauffman, J. Boone; Ward, Darold E.; Haskins, Craig I.; Scholes, Mary C.

    1996-10-01

    Fires are dominant factors in shaping the structure and composition of vegetation in African savanna ecosystems. Emissions such as CO2, NOx, CH4, and other compounds originating from these fires are suspected to contribute substantially to changes in global biogeochemical processes. Limited quantitative data exist detailing characteristics of biomass, burning conditions, and the postfire environment in African savannas. Fourteen test sites, differentiated by distinct burn frequency histories and land-use patterns, were established and burned during August and September 1992 in savanna parklands of South Africa and savanna woodlands of Zambia. Vegetation physiognomy, available fuel loads, the levels of biomass consumed by fire, environmental conditions, and fire behavior are described. In the South African sites, total aboveground fuel loads ranged from 2218 to 5492 kg ha-1 where fire return intervals were 1-4 years and exceeded 7000 kg ha-1 at a site subjected to 38 years of fire exclusion. However, fireline intensity was only 1419 kW m-1 at the fire exclusion site, while ranging from 480 to 6130 kW m-1 among the frequent fire sites. In Zambia, total aboveground fuel loads ranged from 3164 kg ha-1 in a hydromorphic grassland to 7343 kg ha-1 in a fallow shifting cultivation site. Dormant grass and litter constituted 70-98% of the total fuel load among all sites. Although downed woody debris was a relatively minor fuel component at most sites, it constituted 43-57% of the total fuel load in the fire exclusion and shifting cultivation sites. Fire line intensity ranged between 1734 and 4061 kW m-1 among all Zambian sites. Mean grass consumption generally exceeded 95%, while downed woody debris consumption ranged from 3 to 73% at all sites. In tropical savannas and savanna woodlands of southern Africa, differences in environmental conditions, land- use patterns, and fire regimes influence vegetation characteristics and thus influence fire behavior and biomass

  17. Minority drug-resistant HIV-1 variants in treatment naïve East-African and Caucasian patients detected by allele-specific real-time PCR.

    Directory of Open Access Journals (Sweden)

    Halime Ekici

    Full Text Available To assess the presence of two major non-nucleoside reverse transcriptase inhibitors (NNRTI drug resistance mutations (DRMs, Y181C and K103N, in minor viral quasispecies of treatment naïve HIV-1 infected East-African and Swedish patients by allele-specific polymerase chain reaction (AS-PCR.Treatment naïve adults (n=191 with three epidemiological backgrounds were included: 92 Ethiopians living in Ethiopia; 55 East-Africans who had migrated to Sweden; and 44 Caucasians living in Sweden. The pol gene was analysed by standard population sequencing and by AS-PCR for the detection of Y181C and K103N.The Y181C was detected in the minority quasispecies of six Ethiopians (6.5%, in two Caucasians (4.5%, and in one East-African (1.8%. The K103N was detected in one East- African (1.8%, by both methods. The proportion of mutants ranged from 0.25% to 17.5%. Additional DRMs were found in all three treatment naïve patient groups by population sequencing.Major NNRTI mutations can be found by AS-PCR in minor quasispecies of treatment naïve HIV-1 infected Ethiopians living in Ethiopia, in East-African and Caucasian patients living in Sweden in whom population sequencing reveal wild-type virus only. Surveys with standard sequencing are likely to underestimate transmitted drug resistance and the presence of resistant minor quasispecies in treatment naïve patients should be topic for future large scale studies.

  18. The Climate-Population Nexus in the East African Horn: Emerging Degradation Trends in Rangeland and Pastoral Livelihood Zones

    Science.gov (United States)

    Pricope, N. G.; Husak, G. J.; Funk, C. C.; Lopez-Carr, D.

    2014-12-01

    Increasing climate variability and extreme weather conditions along with declining trends in both rainfall and temperature represent major risk factors affecting agricultural production and food security in many regions of the world. We identify regions where significant rainfall decrease from 1979-2011 over the entire continent of Africa couples with significant human population density increase. The rangelands of Ethiopia, Kenya, and Somalia in the East African Horn remain one of the world's most food insecure regions, yet have significantly increasing human populations predominantly dependent on pastoralist and agro-pastoralist livelihoods. Vegetation in this region is characterized by a variable mosaic of land covers, generally dominated by grasslands necessary for agro-pastoralism, interspersed by woody vegetation. Recent assessments indicate that widespread degradation is occurring, adversely impacting fragile ecosystems and human livelihoods. Using two underutilized MODIS products, we observe significant changes in vegetation patterns and productivity over the last decade all across the East African Horn. We observe significant vegetation browning trends in areas experiencing drying precipitation trends in addition to increasing population pressures. We also found that the drying precipitation trends only partially statistically explain the vegetation browning trends, further indicating that other factors such as population pressures and land use changes are responsible for the observed declining vegetation health. Furthermore, we show that the general vegetation browning trends persist even during years with normal rainfall conditions such as 2012, indicating potential long-term degradation of rangelands on which approximately 10 million people depend. These findings have serious implications for current and future regional food security monitoring and forecasting as well as for mitigation and adaptation strategies in a region where population is expected

  19. Imaging rifting at the lithospheric scale in the northern East African Rift using S-to-P receiver functions

    Science.gov (United States)

    Lavayssiere, A.; Rychert, C.; Harmon, N.; Keir, D.; Hammond, J. O. S.; Kendall, J. M.; Leroy, S. D.; Doubre, C.

    2017-12-01

    The lithosphere is modified during rifting by a combination of mechanical stretching, heating and potentially partial melt. We image the crust and upper mantle discontinuity structure beneath the northern East African Rift System (EARS), a unique tectonically active continental rift exposing along strike the transition from continental rifting in the Main Ethiopian rift (MER) to incipient seafloor spreading in Afar and the Red Sea. S-to-P receiver functions from 182 stations across the northern EARS were generated from 3688 high quality waveforms using a multitaper technique and then migrated to depth using a regional velocity model. Waveform modelling of data stacked in large conversion point bins confirms the depth and strength of imaged discontinuities. We image the Moho at 29.6±4.7 km depth beneath the Ethiopian plateaux with a variability in depth that is possibly due to lower crustal intrusions. The crust is 27.3±3.9 km thick in the MER and thinner in northern Afar, 17.5±0.7 km. The model requires a 3±1.2% reduction in shear velocity with increasing depth at 68.5±1.5 km beneath the Ethiopian plateaux, consistent with the lithosphere-asthenosphere boundary (LAB). We do not resolve a LAB beneath Afar and the MER. This is likely associated with partial melt near the base of the lithosphere, reducing the velocity contrast between the melt-intruded lithosphere and the partially molten asthenosphere. We identify a 4.5±0.7% increase in velocity with depth at 91±3 km beneath the MER. This change in velocity is consistent with the onset of melting found by previous receiver functions and petrology studies. Our results provide independent constraints on the depth of melt production in the asthenosphere and suggest melt percolation through the base of the lithosphere beneath the northernmost East African rift.

  20. The Use Of Information And Communication Technology And Social Networking Sites In Political Governance Of East African Legislative Assembly Parliament

    Directory of Open Access Journals (Sweden)

    Ainebyona Robert

    2015-06-01

    Full Text Available Abstract This research project was carried out to ascertain the use of Information and Communication Technologies and Social Networking Sites in political governance of East African Legislative Assembly Parliament. The research project was based on the conviction that in this era of globalization use of ICTs and SNSs are fundamentally important and will have tremendous impact on governance leadership and legislation now and in the near future. The specific objective of this study was intended a To evaluate the use of Social Networking Sites in enhancing the political governance of East African Legislative assembly Parliament. The findings from the research showed that that all the respondents 100 were subscribed to social networking sites and used them from time to time. Additionally the EALA parliamentarians had a disparity when it came to use of SNSs to interact with constituents 73.3 of the respondents indicated that they have used SNSs to interact with constituents on matters affecting the community from time to time however 26.7 showed that they did not use Social Networking sites to interact with constituents. Lastly the use of ICTs and SNSs by EALA has also made it possible for citizens to view Assembly proceedings in real time and hence where able to view their representatives in the course of carrying out their duties in the political arena.Lastly the world is changing in a dynamic fashion SNSs are among the tools leading the transformation and it is about time Parliamentarians in Africa embrace SNSs as major tools in changing how leaders interact and remain accountable to their constituents a practice thats been a myth in Africa.

  1. Mapping International University Partnerships Identified by East African Universities as Strengthening Their Medicine, Nursing, and Public Health Programs.

    Science.gov (United States)

    Yarmoshuk, Aaron N; Guantai, Anastasia Nkatha; Mwangu, Mughwira; Cole, Donald C; Zarowsky, Christina

    International university partnerships are recommended for increasing the capacity of sub-Saharan African universities. Many publications describe individual partnerships and projects, and tools are available for guiding collaborations, but systematic mappings of the basic, common characteristics of partnerships are scarce. To document and categorize the international interuniversity partnerships deemed significant to building the capacity of medicine, nursing, and public health programs of 4 East African universities. Two universities in Kenya and 2 in Tanzania were purposefully selected. Key informant interviews, conducted with 42 senior representatives of the 4 universities, identified partnerships they considered significant for increasing the capacity of their institutions' medicine, nursing, and public health programs in education, research, or service. Interviews were transcribed and analyzed. Partners were classified by country of origin and corresponding international groupings, duration, programs, and academic health science components. One hundred twenty-nine university-to-university partnerships from 23 countries were identified. Each university reported between 25 and 36 international university partners. Seventy-four percent of partnerships were with universities in high-income countries, 15% in low- and middle-income countries, and 11% with consortia. Seventy percent included medicine, 37% nursing, and 45% public health; 15% included all 3 programs. Ninety-two percent included an education component, 47% research, and 24% service; 12% included all 3 components. This study confirms the rapid growth of interuniversity cross-border health partnerships this century. It also finds, however, that there is a pool of established international partnerships from numerous countries at each university. Most partnerships that seek to strengthen universities in East Africa should likely ensure they have a significant education component. Universities should make

  2. East and Central African Journal of Surgery Volume 15 Number 2 ...

    African Journals Online (AJOL)

    DELL

    population live10 and own about 20% of the world's vehicles. The WHO African ... used as a base line for future progression and comparison, these are Motorization index (Vehicle .... Motor vehicle crash. 782. 0. 0. 0 ... Electric accident. 36. 0. 0.

  3. Innovations in sanitation for sustainable urban growth; modernized mixtures in an east african context

    NARCIS (Netherlands)

    Letema, S.; Van Vliet, B.; Van Lier, J.B.

    2012-01-01

    Urbanisation of poverty and informality in East Africa poses a threat to public health and environmental protection, perpetuating social exclusion and inequalities, while it creates service gaps. Neither conventional on-site sanitation nor modern centralised off-site sanitation provisions are

  4. Epidemic malaria and warmer temperatures in recent decades in an East African highland

    NARCIS (Netherlands)

    Alonso, David; Bouma, Menno J.; Pascual, Mercedes

    2011-01-01

    Climate change impacts on malaria are typically assessed with scenarios for the long-term future. Here we focus instead on the recent past (1970-2003) to address whether warmer temperatures have already increased the incidence of malaria in a highland region of East Africa. Our analyses rely on a

  5. Prediction of East African Seasonal Rainfall Using Simplex Canonical Correlation Analysis.

    Science.gov (United States)

    Ntale, Henry K.; Yew Gan, Thian; Mwale, Davison

    2003-06-01

    A linear statistical model, canonical correlation analysis (CCA), was driven by the Nelder-Mead simplex optimization algorithm (called CCA-NMS) to predict the standardized seasonal rainfall totals of East Africa at 3-month lead time using SLP and SST anomaly fields of the Indian and Atlantic Oceans combined together by 24 simplex optimized weights, and then `reduced' by the principal component analysis. Applying the optimized weights to the predictor fields produced better March-April-May (MAM) and September-October-November (SON) seasonal rain forecasts than a direct application of the same, unweighted predictor fields to CCA at both calibration and validation stages. Northeastern Tanzania and south-central Kenya had the best SON prediction results with both validation correlation and Hanssen-Kuipers skill scores exceeding +0.3. The MAM season was better predicted in the western parts of East Africa. The CCA correlation maps showed that low SON rainfall in East Africa is associated with cold SSTs off the Somali coast and the Benguela (Angola) coast, and low MAM rainfall is associated with a buildup of low SSTs in the Indian Ocean adjacent to East Africa and the Gulf of Guinea.

  6. Journal of East African Natural History - Vol 88, No 1 (1999)

    African Journals Online (AJOL)

    Canthariphilous insects in east Africa · EMAIL FULL TEXT EMAIL FULL TEXT DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. C Hemp, A Hemp, K Dettner, 1-15. http://dx.doi.org/10.2982/0012-8317(1999)88[1:CIIEA]2.0.CO;2 ...

  7. Journal of East African Natural History - Vol 86, No 1 (1997)

    African Journals Online (AJOL)

    1997)86[1:ACIT]2.0.CO;2 · New fern records for Kilimanjaro · EMAIL FULL TEXT EMAIL FULL TEXT DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. Andreas Hemp, 37-42. Zoogeography and biodiversity of syrphidae (Diptera) in East Africa ...

  8. A Scoring Tool to Identify East African HIV-1 Serodiscordant Partnerships with a High Likelihood of Pregnancy.

    Directory of Open Access Journals (Sweden)

    Renee Heffron

    Full Text Available HIV-1 prevention programs targeting HIV-1 serodiscordant couples need to identify couples that are likely to become pregnant to facilitate discussions about methods to minimize HIV-1 risk during pregnancy attempts (i.e. safer conception or effective contraception when pregnancy is unintended. A clinical prediction tool could be used to identify HIV-1 serodiscordant couples with a high likelihood of pregnancy within one year.Using standardized clinical prediction methods, we developed and validated a tool to identify heterosexual East African HIV-1 serodiscordant couples with an increased likelihood of becoming pregnant in the next year. Datasets were from three prospectively followed cohorts, including nearly 7,000 couples from Kenya and Uganda participating in HIV-1 prevention trials and delivery projects.The final score encompassed the age of the woman, woman's number of children living, partnership duration, having had condomless sex in the past month, and non-use of an effective contraceptive. The area under the curve (AUC for the probability of the score to correctly predict pregnancy was 0.74 (95% CI 0.72-0.76. Scores ≥ 7 predicted a pregnancy incidence of >17% per year and captured 78% of the pregnancies. Internal and external validation confirmed the predictive ability of the score.A pregnancy likelihood score encompassing basic demographic, clinical and behavioral factors defined African HIV-1 serodiscordant couples with high one-year pregnancy incidence rates. This tool could be used to engage African HIV-1 serodiscordant couples in counseling discussions about fertility intentions in order to offer services for safer conception or contraception that align with their reproductive goals.

  9. A Scoring Tool to Identify East African HIV-1 Serodiscordant Partnerships with a High Likelihood of Pregnancy.

    Science.gov (United States)

    Heffron, Renee; Cohen, Craig R; Ngure, Kenneth; Bukusi, Elizabeth; Were, Edwin; Kiarie, James; Mugo, Nelly; Celum, Connie; Baeten, Jared M

    2015-01-01

    HIV-1 prevention programs targeting HIV-1 serodiscordant couples need to identify couples that are likely to become pregnant to facilitate discussions about methods to minimize HIV-1 risk during pregnancy attempts (i.e. safer conception) or effective contraception when pregnancy is unintended. A clinical prediction tool could be used to identify HIV-1 serodiscordant couples with a high likelihood of pregnancy within one year. Using standardized clinical prediction methods, we developed and validated a tool to identify heterosexual East African HIV-1 serodiscordant couples with an increased likelihood of becoming pregnant in the next year. Datasets were from three prospectively followed cohorts, including nearly 7,000 couples from Kenya and Uganda participating in HIV-1 prevention trials and delivery projects. The final score encompassed the age of the woman, woman's number of children living, partnership duration, having had condomless sex in the past month, and non-use of an effective contraceptive. The area under the curve (AUC) for the probability of the score to correctly predict pregnancy was 0.74 (95% CI 0.72-0.76). Scores ≥ 7 predicted a pregnancy incidence of >17% per year and captured 78% of the pregnancies. Internal and external validation confirmed the predictive ability of the score. A pregnancy likelihood score encompassing basic demographic, clinical and behavioral factors defined African HIV-1 serodiscordant couples with high one-year pregnancy incidence rates. This tool could be used to engage African HIV-1 serodiscordant couples in counseling discussions about fertility intentions in order to offer services for safer conception or contraception that align with their reproductive goals.

  10. A review of visceral leishmaniasis during the conflict in South Sudan and the consequences for East African countries.

    Science.gov (United States)

    Al-Salem, Waleed; Herricks, Jennifer R; Hotez, Peter J

    2016-08-22

    Visceral leishmaniasis (VL), caused predominantly by Leishmania donovani and transmitted by both Phlebotomus orientalis and Phlebotomus martini, is highly endemic in East Africa where approximately 30 thousands VL cases are reported annually. The largest numbers of cases are found in Sudan - where Phlebotomus orientalis proliferate in Acacia forests especially on Sudan's eastern border with Ethiopia, followed by South Sudan, Ethiopia, Somalia, Kenya and Uganda. Long-standing civil war and unrest is a dominant determinant of VL in East African countries. Here we attempt to identify the correlation between VL epidemics and civil unrest. In this review, literature published between 1955 and 2016 have been gathered from MSF, UNICEF, OCHA, UNHCR, PubMed and Google Scholar to analyse the correlation between conflict and human suffering from VL, which is especially apparent in South Sudan. Waves of forced migration as a consequence of civil wars between 1983 and 2005 have resulted in massive and lethal epidemics in southern Sudan. Following a comprehensive peace agreement, but especially with increased allocation of resources for disease treatment and prevention in 2011, cases of VL declined reaching the lowest levels after South Sudan declared independence. However, in the latest epidemic that began in 2014 after the onset of a civil war in South Sudan, more than 1.5 million displaced refugees have migrated internally to states highly endemic for VL, while 800,000 have fled to neighboring countries. We find a strong relationship between civil unrest and VL epidemics which tend to occur among immunologically naïve migrants entering VL-endemic areas and when Leishmania-infected individuals migrate to new areas and establish additional foci of disease. Further complicating factors in East Africa's VL epidemics include severe lack of access to diagnosis and treatment, HIV/AIDS co-infection, food insecurity and malnutrition. Moreover, cases of post-kala-azar dermal

  11. The ‘complete gospel’ revisited: Middle East and African influences

    Directory of Open Access Journals (Sweden)

    Glenna S. Jackson

    2014-11-01

    Full Text Available The author focuses on the historically-reliable gospel pericopes in which a woman is the lead character. She argues that these women provide the complete gospel − Jesus teaches, heals, preaches and is anointed in the context of female-based stories and, of course, the women take him from conception to resurrection. Jackson argues, not only from an analysis of the texts themselves, but also from her personal experiences in the Middle East and Africa.

  12. Gender Equity in Mathematics Achievement in East African Primary Schools: Context Counts

    OpenAIRE

    Tia L. Zuze; Valerie E. Lee

    2007-01-01

    Although primary school enrollment is gradually on the increase in the developing world, differences in mathematics achievement between girls and boys persist. A complex combination of factors that is related to issues of the home environment, the school context, and national policy influences the performance of female students when compared to their male peers. We focus on three countries in East Africa with a female disadvantage in mathematics achievement and use data from 8,795 primary sch...

  13. Acral peeling skin syndrome in two East-African siblings: case report

    Directory of Open Access Journals (Sweden)

    Kiprono Samson K

    2012-03-01

    Full Text Available Abstract Background Acral peeling skin syndrome is a rare autosomal recessive genodermatosis due to a missense mutation in transglutaminase 5. The skin peeling occurs at the separation of the stratum corneum from the stratum granulosum. Case presentation We present a case of two siblings who developed continuous peeling of the palms and soles from the first year of life. This peeling was more severe on the soles than palms and on younger sibling than elder sibling. Peeling is worsened by occlusion and sweating. Conclusions Sporadic cases of Acral Peeling Skin Syndrome occur in African population. There is variability in time of presentation and clinical severity even within families.

  14. Acral peeling skin syndrome in two East-African siblings: case report.

    Science.gov (United States)

    Kiprono, Samson K; Chaula, Baraka M; Naafs, Bernard; Masenga, John E

    2012-03-19

    Acral peeling skin syndrome is a rare autosomal recessive genodermatosis due to a missense mutation in transglutaminase 5. The skin peeling occurs at the separation of the stratum corneum from the stratum granulosum. We present a case of two siblings who developed continuous peeling of the palms and soles from the first year of life. This peeling was more severe on the soles than palms and on younger sibling than elder sibling. Peeling is worsened by occlusion and sweating. Sporadic cases of Acral Peeling Skin Syndrome occur in African population. There is variability in time of presentation and clinical severity even within families.

  15. Disaggregating tree and grass phenology in tropical savannas

    Science.gov (United States)

    Zhou, Qiang

    method was better for extracting the green tree phenology, but the original decomposition method was better for retrieval of understory grass phenology. Both methods, however, were less accurate than in the Cerrado than in Australia due to intermingling and intergrading of grass and small woody components. Since African savanna trees are predominantly deciduous, the frequency method was combined with the linear unmixing of fractional cover to attempt to separate the relatively similar phenology of deciduous trees and seasonal grasses. The results for Africa revealed limitations associated with both methods. There was spatial and seasonal variation in the spectral indices used to unmix fractional cover resulting in poor validation for NPV in particular. The frequency analysis revealed significant phase variation indicative of different phenology, but these could not be clearly ascribed to separate grass and tree components. Overall findings indicate that site-specific variation and vegetation structure and composition, along with MODIS pixel resolution, and the simple vegetation index approach used was not robust across the different savanna biomes. The approach showed generally better performance for estimating PV fraction, and separating green phenology, but there were major inconsistencies, errors and biases in estimation of NPV and BS outside of the Australian savanna environment.

  16. Pastoralism and wildlife: historical and current perspectives in the East African rangelands of Kenya and Tanzania.

    Science.gov (United States)

    Lankester, F; Davis, A

    2016-11-01

    The relationship between pastoralists, their livestock, wildlife and the rangelands of East Africa is multi-directional, complex and long-standing. The tumultuous events of the past century, however, have rewritten the nature of this relationship, reshaping the landscapes that were created, and relied upon, by both pastoralists and wildlife. Presently, much of the interaction between wildlife and pastoralists takes place in and around protected areas, the most contentious occurring in pastoral lands surrounding national parks. In conservation terminology these areas are called buffer zones. In the past century buffer zones have been shaped by, and contributed to, restrictive conservation policies, expropriation of land, efforts to include communities in conservation, both positive and negative wildlife/livestock interactions, and political tensions. In this review paper, the authors outline the history that shaped the current relationship between pastoralists, livestock and wildlife in buffer zones in East Africa and highlight some of the broader issues that pastoralists (and pastoralism as an effective livelihood strategy) now face. Finally, they consider some of the sustainable and equitable practices that could be implemented to improve livelihoods and benefit wildlife and pastoralism alike.

  17. A methodology to track temporal dynamics and rainfall thresholds of landslide processes in the East African Rift

    Science.gov (United States)

    Monsieurs, Elise; Jacobs, Liesbet; Kervyn, François; Kirschbaum, Dalia; d'Oreye, Nicolas; Derauw, Dominique; Kervyn, Matthieu; Nobile, Adriano; Trefois, Philippe; Dewitte, Olivier

    2015-04-01

    The East African rift valley is a major tectonic feature that shapes Central Africa and defines linear-shaped lowlands between highland ranges due to the action of geologic faults associated to earthquakes and volcanism. The region of interest, covering the Virunga Volcanic Province in eastern DRC, western Rwanda and Burundi, and southwest Uganda, is threatened by a rare combination of several types of geohazards, while it is also one of the most densely populated region of Africa. These geohazards can globally be classified as seismic, volcanic and landslide hazards. Landslides, include a wide range of ground movements, such as rock falls, deep failure of slopes and shallow debris flows. Landslides are possibly the most important geohazard in terms of recurring impact on the populations, causing fatalities every year and resulting in structural and functional damage to infrastructure and private properties, as well as serious disruptions of the organization of societies. Many landslides are observed each year in the whole region, and their occurrence is clearly linked to complex topographic, lithologic and vegetation signatures coupled with heavy rainfall events, which is the main triggering factor. The source mechanisms underlying landslide triggering and dynamics in the region of interest are still poorly understood, even though in recent years, some progress has been made towards appropriate data collection. Taking into account difficulties of field accessibility, we present a methodology to study landslide processes by multi-scale and multi-sensor remote sensing data from very high to low resolution (Pléiades, TRMM, CosmoSkyMed, Sentinel). The research will address the evolution over time of such data combined with other earth observations (seismic ground based networks, catalogues, rain gauge networks, GPS surveying, field observations) to detect and study landslide occurrence, dynamics and evolution. This research aims to get insights into the rainfall

  18. Advancing the Structural Use of Earth-based Bricks: Addressing Key Challenges in the East African Context

    Directory of Open Access Journals (Sweden)

    Mang Tia

    2010-11-01

    Full Text Available The research discussed in this paper is a subset of a bigger, NSF funded research project that is directed at investigating the use of sustainable building materials. The deployment context for the research is the hot and humid climate using selected cases from the East African region. The overarching goal for the research is advancing the structural use of earth-based technologies. Significant strides can be made through developing strategies for countering the adverse factors that affect the structural performance of the resulting wall, especially ones related to moisture dynamics. The research was executed in two phases. The first phase was a two-day NSF supported workshop which was held in Tanzania in July 2009. It provided a forum for sharing best practices in earth-based building technologies and developing a research and development roadmap. The priority research areas were broadly classified as optimizing the physio-mechanical properties of earth as a building material and managing socio-cultural impediments. In the second phase of the research, the authors collaborated with researchers from East Africa to conduct experimental work on the optimization of physio-mechanical properties. The specific research issues that have been addressed are: (1 characterizing the chemical reactions that can be linked to deterioration triggered by hygrothermal loads based on the hot and humid context, and; (2 developing a prototype for a simpler, portable, affordable and viable compressed brick production machine. The paper discusses the results from the characterization work that ultimately will be used to design bricks that have specific properties based on an understanding of how different stabilizers affect the hydration process. It also describes a cheaper, portable and more efficient prototype machine that has been developed as part of the follow-up research activities.

  19. Fundamental Flaws in the Architecture of the European Central Bank: The Possible End of the Euro Zone and its Effects to East African Community (EAC Countries

    Directory of Open Access Journals (Sweden)

    Nothando Moyo

    2014-09-01

    Full Text Available European countries embarked on a European integration programme that saw the formation of the Euro, which has emerged as a major currency (Blair, 1999 that was introduced in 1998. With the Euro, came the establishment of the European Central Bank. Thus this study seeks to investigate the flaws in the formation of the European Central Bank that surfaced during the major economic crisis in Europe. The crisis revealing the gaps in the formation and structure of the European central bank have created major challenges for the Economic and Monetary Union (EMU. Through an extant review of literature the study will examine the East African Community Countries, investigating the ties they have to the euro zone to analyse how the crisis has affected them. Furthermore, the study will analyse what would happen to the growth patterns of the East African Countries and the various prospects they may have should the Eurozone come to an end.

  20. Vitamin D intake, serum 25-hydroxyvitamin D status and response to moderate vitamin D3 supplementation: a randomised controlled trial in East African and Finnish women.

    Science.gov (United States)

    Adebayo, Folasade A; Itkonen, Suvi T; Öhman, Taina; Skaffari, Essi; Saarnio, Elisa M; Erkkola, Maijaliisa; Cashman, Kevin D; Lamberg-Allardt, Christel

    2018-02-01

    Insufficient vitamin D status (serum 25-hydroxyvitamin D (S-25(OH)D)0·05 for differences between ethnic groups). In conclusion, high prevalence of vitamin D insufficiency existed among East African women living in Finland, despite higher vitamin D intake than their Finnish peers. Moderate vitamin D3 supplementation was effective in increasing S-25(OH)D in both groups of women, and no ethnic differences existed in the response to supplementation.

  1. Littoral sedimentation of rift lakes: an illustrated overview from the modern to Pliocene Lake Turkana (East African Rift System, Kenya)

    Science.gov (United States)

    Schuster, Mathieu; Nutz, Alexis

    2015-04-01

    Existing depositional models for rift lakes can be summarized as clastics transported by axial and lateral rivers, then distributed by fan-deltas and/or deltas into a standing water body which is dominated by settling of fine particles, and experiencing occasional coarser underflows. Even if known from paleolakes and modern lakes, reworking of clastics by alongshore drift, waves and storms are rarely considered in depositional models. However, if we consider the lake Turkana Basin (East African Rift System, Kenya) it is obvious that this vision is incomplete. Three representative time slices are considered here: the modern Lake Turkana, the Megalake Turkana which developed thanks to the African Humid Period (Holocene), and the Plio-Pleistocene highstand episodes of paleolake Turkana (Nachukui, Shungura and Koobi Fora Formations, Omo Group). First, remarkable clastic morphosedimentary structures such as beach ridges, spits, washover fans, lagoons, or wave-dominated deltas are very well developed along the shoreline of modern lake Turkana, suggesting strong hydrodynamics responsible for a major reworking of the fluvial-derived clastics all along the littoral zone (longshore and cross-shore transport) of the lake. Similarly, past hydrodynamics are recorded from prominent raised beach ridges and spits, well-preserved all around the lake, above its present water-level (~360 m asl) and up to ~455 m. These large-scale clastic morphosedimentary structures also record the maximum extent of Megalake Turkana during the African Humid Period, as well as its subsequent regression forced by the end of the Holocene climatic optimum. Several hundreds of meters of fluvial-deltaic-lacustrine deposits spanning the Pliocene-Pleistocene are exposed in the Turkana basin thanks to tectonic faulting. These deposits are world famous for their paleontological and archeological content that documents the very early story of Mankind. They also preserve several paleolake highstand episodes with

  2. Contribution to the Investigation of Structure and Origin of the East African Graben by Gravimetry

    Institute of Scientific and Technical Information of China (English)

    Tondozi Keto; LIU Tianyou

    2005-01-01

    For our investigation we have 235 measurements done in the east part of Democratic Republic of Congo by P. Herrinck during a magnetic survey including the graben region from the parallel joining Goma city and Mahagi city, the region between Albert and Aka lakes, and the route from Aba to Kinsagani. During the surveys the density of recording points has been selected according to the importance of anomalies. In this way, the offset was 1 km where the disturbance was high in Goma city and 20 km have been sufficient along the route from Aba to Kinsagani. For the topographic and isostatic reductions only one cartographic document has been chosen that was the international map of the scale 1/1 000 000 which presents a certain characteristic of homogeneity.

  3. Isolation and molecular characterization of Chikungunya virus from the Andaman and Nicobar archipelago, India: evidence of an East, Central, and South African genotype.

    Science.gov (United States)

    Muruganandam, N; Chaaithanya, I K; Senthil, G S; Shriram, A N; Bhattacharya, D; Jeevabharathi, G S; Sudeep, A B; Pradeepkumar, N; Vijayachari, P

    2011-12-01

    Chikungunya virus (CHIKV) is an Alphavirus belonging to the family Togaviridae. In 2006, CHIKV infection struck the Andaman and Nicobar archipelago, with an attack rate of 60%. There were more than 10 cases with acute flaccid paralysis simulating the Guillian Barre Syndrome. The majority of the patients presented severe joint pain. The cause for such an explosive nature of the outbreak with increased morbidity was not known. The isolation of CHIKV was attempted and succeeded from nine subjects presenting clinical symptoms of Chikungunya fever. The cDNA of all the isolates was sequenced for partial E1 and nsP1 genes. Sequences were aligned based on the double locus sequence typing concept. The phylogenetic analysis shows that sequences of Andaman isolates grouped with the East, Central, and South African genotype of virus isolates from India, Sri Lanka, and Réunion. The genetic distance between Andaman isolates and the Réunion isolates was very small. The phylogenetic analysis confirmed the origin of the isolates responsible for the first ever confirmed CHIKV outbreak in these islands to be the East, Central, and South African genotype. In this manuscript, we discuss the involvement of the East, Central, and South African strain with the Chikungunya fever outbreak in this archipelago and double locus sequence typing as a first time approach.

  4. Genetic adaptation of giant lobelias (Lobelia aberdarica and Lobelia telekii to different altitudes in East African mountains

    Directory of Open Access Journals (Sweden)

    Shu-Ying eZhao

    2016-04-01

    Full Text Available The giant lobelias in East African mountains are good models for studying molecular mechanisms of adaptation to different altitudes. In this study, we generated RNA-seq data of a middle-altitude species Lobelia aberdarica and a high-altitude species L. telekii, followed by selective pressure estimation of their orthologous genes. Our aim was to explore the important genes potentially involved in adaptation to different altitudes. About 9.3 Gb of clean nucleotides, 167,929 – 170,534 unigenes with total lengths of 159,762,099 – 171,138,936 bp for each of the two species were generated. OrthoMCL method identified 3,049 1:1 orthologous genes (each species was represented by one ortholog. Estimations of non-synonymous to synonymous rate were performed using an approximate method and a maximum likelihood method in PAML. 85 orthologous genes were under positive selection. At least 8 of these genes are possibly involved in DNA repair, response to DNA damage and temperature stimulus, and regulation of gene expression, which hints on how giant lobelias adapt to high altitudinal environment that characterised by cold, low oxygen and strong ultraviolet radiation. The negatively selected genes are over-represented in Gene ontology terms of hydrolase, macromolecular complex assembly among others. This study sheds light on understanding the molecular mechanism of adaptation to different altitudes, and provides genomic resources for further studies of giant lobelias.

  5. Mortality in East African shorthorn zebu cattle under one year: predictors of infectious-disease mortality.

    Science.gov (United States)

    Thumbi, Samuel M; Bronsvoort, Mark B M de C; Kiara, Henry; Toye, P G; Poole, Jane; Ndila, Mary; Conradie, Ilana; Jennings, Amy; Handel, Ian G; Coetzer, J A W; Steyl, Johan; Hanotte, Olivier; Woolhouse, Mark E J

    2013-09-08

    Infectious livestock diseases remain a major threat to attaining food security and are a source of economic and livelihood losses for people dependent on livestock for their livelihood. Knowledge of the vital infectious diseases that account for the majority of deaths is crucial in determining disease control strategies and in the allocation of limited funds available for disease control. Here we have estimated the mortality rates in zebu cattle raised in a smallholder mixed farming system during their first year of life, identified the periods of increased risk of death and the risk factors for calf mortality, and through analysis of post-mortem data, determined the aetiologies of calf mortality in this population. A longitudinal cohort study of 548 zebu cattle was conducted between 2007 and 2010. Each calf was followed during its first year of life or until lost from the study. Calves were randomly selected from 20 sub-locations and recruited within a week of birth from different farms over a 45 km radius area centered on Busia in the Western part of Kenya. The data comprised of 481.1 calf years of observation. Clinical examinations, sample collection and analysis were carried out at 5 week intervals, from birth until one year old. Cox proportional hazard models with frailty terms were used for the statistical analysis of risk factors. A standardized post-mortem examination was conducted on all animals that died during the study and appropriate samples collected. The all-cause mortality rate was estimated at 16.1 (13.0-19.2; 95% CI) per 100 calf years at risk. The Cox models identified high infection intensity with Theileria spp., the most lethal of which causes East Coast Fever disease, infection with Trypanosome spp., and helminth infections as measured by Strongyle spp. eggs per gram of faeces as the three important infections statistically associated with infectious disease mortality in these calves. Analysis of post-mortem data identified East Coast Fever as

  6. Middle east and North African oil in international relations (from 1970 to these days)

    International Nuclear Information System (INIS)

    Rafie, Hossein

    1999-01-01

    Petroleum is not purely an economical product, its main role in world economy and its concentration in Middle East and North Africa (two third of world reserves) made influence international politics. Knowing the nature of the region, petroleum and politics make one. The politicization of oil in the region starts, first of all, with the efforts of some powers, through their companies, to dominate oil countries, which by reaction incite these countries to eliminate foreign domination and establish their national control on oil matters. The situation is changing progressively. The position of productive states got stronger with the beginning of the 1970's which permitted the use of oil, in a way relatively efficient, as an instrument of power. Consequently, the balance of power shifted deeply in the favor of producers. On this basis, the argument consists of three parts: the first puts theoretic bases - theory of economical arm - and defines geographical and historical environment of the research. The second part studies the period of force of the oil countries, from the fourth Israel-Arab war and oil embargo that followed it, to the end of the second oil slump. The third part explains the shift of power on the international scene and the relative decline of oil power for the states of the region. The analysis of impact of the oil slump in 1986 and the mini impact of the second Persian Gulf war, quickly dominated, lead to clear the actual situation and outline the viewpoint of the future. (author)

  7. Otoliths of Five Extant Species of the Annual Killifish Nothobranchius from the East African Savannah

    Science.gov (United States)

    Reichenbacher, Bettina; Reichard, Martin

    2014-01-01

    This study presents, for the first time, a comprehensive dataset that documents the range of inter- and intraspecific otolith variation in aplocheiloid killifish, based on a total of 86 individuals representing five extant species of Nothobranchius PETERS, 1868, from East Africa: the sympatric pairs N. rubripinnis SEEGERS, 1986 and N. ruudwildekampi COSTA, 2009 (Eastern Tanzania), and N. orthonotus (PETERS, 1844) and N. furzeri JUBB, 1971 (Southern Mozambique), and two isolated populations of N. korthausae MEINKEN, 1973 (Eastern Tanzania). Otolith characters were analysed based on SEM images, and otolith morphometry was conducted using uni- and multivariate statistics. Two ancient clades of probably Early to Middle Miocene age in eastern Tanzania and southern Mozambique can be recognized based on otolith morphologies, which is consistent with previous work based on molecular data. The distinctive sulcus morphologies in the otoliths of sympatric species may be linked to species-specific hearing capabilities, perhaps constituting a case of character displacement in an area of secondary sympatry. The otoliths of the studied species of Nothobranchius are diagnostic at the species level, even in the case of closely related species diagnosable otherwise only by minor differences in coloration. The two populations of N. korthausae also displayed some differences in their otolith characters. The new data may facilitate future recognition of fossil species of Nothobranchius. As no fossil remains of extant aplocheiloid killifishes have yet been described, the discovery of fossil otoliths of Nothobranchius would significantly advance understanding of the evolutionary history of this interesting group of fishes. PMID:25383789

  8. Extent of East-African Nurse Leaders’ Participation in Health Policy Development

    Directory of Open Access Journals (Sweden)

    N. Shariff

    2012-01-01

    Full Text Available This paper reports part of a bigger study whose aim was to develop an empowerment model that could be used to enhance nurse leaders’ participation in health policy development. A Delphi survey was applied which included the following criteria: expert panelists, iterative rounds, statistical analysis, and consensus building. The expert panelists were purposively selected and included national nurse leaders in leadership positions at the nursing professional associations, nursing regulatory bodies, ministries of health, and universities in East Africa. The study was conducted in three iterative rounds. The results reported here were gathered as part of the first round of the study and that examined the extent of nurse leaders’ participation in health policy development. Seventy-eight (78 expert panelists were invited to participate in the study, and the response rate was 47%. Data collection was done with the use of a self-report questionnaire. Data analysis was done by use of SPSS and descriptive statistics were examined. The findings indicated that nurse leaders participate in health policy development though participation is limited and not consistent across all the stages of health policy development. The recommendations from the findings are that health policy development process needs to be pluralistic and inclusive of all nurse leaders practicing in positions related to policy development and the process must be open to their ideas and suggestions.

  9. Strategic management of livestock to improve biodiversity conservation in African savannahs: A conceptual basis for wildlife-livestock coexistence

    Science.gov (United States)

    African savannas are complex socio-ecological systems with diverse wild and domestic herbivore assemblages, which utilize functional heterogeneity of habitats to adapt to intra- and inter-annual variation in forage quantity and quality, predation and disease risks. As African savannas become increas...

  10. Planation surfaces as a record of medium to large wavelength deformation: the example of the Lake Albert Rift (Uganda) on the East African Dome

    Science.gov (United States)

    Brendan, Simon; François, Guillocheau; Cécile, Robin; Jean, Braun; Olivier, Dauteuil; Massimo, Dall'Asta

    2016-04-01

    African relief is characterized by planation surfaces, some of them of continental scale. These surfaces are slightly deformed according to different wavelengths (x10 km; x100 km, x1000 km) which record both mantle dynamics (very long wavelength, x 1000 km) and lithosphere deformation (long wavelength deformation, x 100 km). Different types of these planation surfaces are recognized: - Etchplains capped by iron-duricrust which correspond to erosional nearly flat weathered surfaces resulting from the growth of laterites under warm and humid conditions. - Pediments which define mechanical erosional surfaces with concave or rectilinear profiles delimited by upslope scarps connected upstream with the upper landforms. We here focused on the Lake Albert Rift at the northern termination of the western branch of the East African Rift System of which the two branches are surimposed on the East-African Dome. Different wavelengths of deformation were characterized based on the 3D mapping of stepped planation surfaces: (1) very long wavelength deformations resulting from the uplift of the East African Dome; (2) long wavelength deformations resulting from the opening of the eastern branch and (3) medium wavelength deformations represented by the uplift of rift shoulders like the Rwenzori Mountains. The paleo-landscape reconstruction of Uganda shows the existence of four generations of landforms dated according to their geometrical relationships with volcanic rocks. A four stepped evolution of the Ugandan landforms is proposed: • 70 - 22 Ma: generation of two weathered planation surfaces (etchplain Uw and Iw). The upper one (Uw) records a very humid period culminating at time of the Early Eocene Climatic Optimum (70-45 Ma). It corresponds to the African Surface. A first uplift of the East African Dome generates a second lower planation surface (Iw) connected to the Atlantic Ocean base level; • 17-2.7 Ma: planation of large pediplains connected to the local base level induced

  11. Functional traits of trees on and off termite mounds : Understanding the origin of biotically-driven heterogeneity in savannas

    NARCIS (Netherlands)

    van der Plas, F.; Howison, R.; Reinders, J.; Fokkema, W.; Olff, H.

    Questions In African savannas, Macrotermes termites contribute to small-scale heterogeneity by constructing large mounds. Operating as islands of high nutrient and water availability and low fire frequency, these mounds support distinct, diverse communities of trees that have been shown to be highly

  12. Socioeconomic Differences in Dietary Patterns in an East African Country: Evidence from the Republic of Seychelles.

    Science.gov (United States)

    Mayén, Ana-Lucia; Bovet, Pascal; Marti-Soler, Helena; Viswanathan, Bharathi; Gedeon, Jude; Paccaud, Fred; Marques-Vidal, Pedro; Stringhini, Silvia

    2016-01-01

    In high income countries, low socioeconomic status (SES) is related to unhealthier dietary patterns, while evidence on the social patterning of diet in low and middle income countries is scarce. In this study, we assess dietary patterns in the general population of a middle income country in the African region, the Republic of Seychelles, and examine their distribution according to educational level and income. Data was drawn from two independent national surveys conducted in the Seychelles among adults aged 25-64 years in 2004 (n = 1236) and 2013 (n = 1240). Dietary patterns were assessed by principal component analysis (PCA). Educational level and income were used as SES indicators. Data from both surveys were combined as no interaction was found between SES and year. Three dietary patterns were identified: "snacks and drinks", "fruit and vegetables" and "fish and rice". No significant associations were found between SES and the "snacks and drinks" pattern. Low vs. high SES individuals had lower adherence to the "fruit and vegetables" pattern [prevalence ratio (95% CI) 0.71 (0.60-0.83)] but a higher adherence to the traditional "fish and rice" pattern [1.58 (1.32-1.88)]. Income modified the association between education and the "fish and rice" pattern (p = 0.02), whereby low income individuals had a higher adherence to this pattern in both educational groups. Low SES individuals have a lower consumption of fruit and vegetables, but a higher consumption of traditional foods like fish and rice. The Seychelles may be at a degenerative diseases stage of the nutrition transition.

  13. Methods for sampling geographically mobile female traders in an East African market setting

    Science.gov (United States)

    Achiro, Lillian; Kwena, Zachary A.; McFarland, Willi; Neilands, Torsten B.; Cohen, Craig R.; Bukusi, Elizabeth A.; Camlin, Carol S.

    2018-01-01

    Background The role of migration in the spread of HIV in sub-Saharan Africa is well-documented. Yet migration and HIV research have often focused on HIV risks to male migrants and their partners, or migrants overall, often failing to measure the risks to women via their direct involvement in migration. Inconsistent measures of mobility, gender biases in those measures, and limited data sources for sex-specific population-based estimates of mobility have contributed to a paucity of research on the HIV prevention and care needs of migrant and highly mobile women. This study addresses an urgent need for novel methods for developing probability-based, systematic samples of highly mobile women, focusing on a population of female traders operating out of one of the largest open air markets in East Africa. Our method involves three stages: 1.) identification and mapping of all market stall locations using Global Positioning System (GPS) coordinates; 2.) using female market vendor stall GPS coordinates to build the sampling frame using replicates; and 3.) using maps and GPS data for recruitment of study participants. Results The location of 6,390 vendor stalls were mapped using GPS. Of these, 4,064 stalls occupied by women (63.6%) were used to draw four replicates of 128 stalls each, and a fifth replicate of 15 pre-selected random alternates for a total of 527 stalls assigned to one of five replicates. Staff visited 323 stalls from the first three replicates and from these successfully recruited 306 female vendors into the study for a participation rate of 94.7%. Mobilization strategies and involving traders association representatives in participant recruitment were critical to the study’s success. Conclusion The study’s high participation rate suggests that this geospatial sampling method holds promise for development of probability-based samples in other settings that serve as transport hubs for highly mobile populations. PMID:29324780

  14. Genetic susceptibility to infectious disease in East African Shorthorn Zebu: a genome-wide analysis of the effect of heterozygosity and exotic introgression.

    Science.gov (United States)

    Murray, Gemma G R; Woolhouse, Mark E J; Tapio, Miika; Mbole-Kariuki, Mary N; Sonstegard, Tad S; Thumbi, Samuel M; Jennings, Amy E; van Wyk, Ilana Conradie; Chase-Topping, Margo; Kiara, Henry; Toye, Phil; Coetzer, Koos; deC Bronsvoort, Barend M; Hanotte, Olivier

    2013-11-09

    Positive multi-locus heterozygosity-fitness correlations have been observed in a number of natural populations. They have been explained by the correlation between heterozygosity and inbreeding, and the negative effect of inbreeding on fitness (inbreeding depression). Exotic introgression in a locally adapted population has also been found to reduce fitness (outbreeding depression) through the breaking-up of co-adapted genes, or the introduction of non-locally adapted gene variants. In this study we examined the inter-relationships between genome-wide heterozygosity, introgression, and death or illness as a result of infectious disease in a sample of calves from an indigenous population of East African Shorthorn Zebu (crossbred Bos taurus x Bos indicus) in western Kenya. These calves were observed from birth to one year of age as part of the Infectious Disease in East African Livestock (IDEAL) project. Some of the calves were found to be genetic hybrids, resulting from the recent introgression of European cattle breed(s) into the indigenous population. European cattle are known to be less well adapted to the infectious diseases present in East Africa. If death and illness as a result of infectious disease have a genetic basis within the population, we would expect both a negative association of these outcomes with introgression and a positive association with heterozygosity. In this indigenous livestock population we observed negative associations between heterozygosity and both death and illness as a result of infectious disease and a positive association between European taurine introgression and episodes of clinical illness. We observe the effects of both inbreeding and outbreeding depression in the East African Shorthorn Zebu, and therefore find evidence of a genetic component to vulnerability to infectious disease. These results indicate that the significant burden of infectious disease in this population could, in principle, be reduced by altered breeding

  15. Famine Early Warning Systems Network (FEWS NET) Contributions to Strengthening Resilience and Sustainability for the East African Community

    Science.gov (United States)

    Budde, M. E.; Galu, G.; Funk, C. C.; Verdin, J. P.; Rowland, J.

    2014-12-01

    The Planning for Resilience in East Africa through Policy, Adaptation, Research, and Economic Development (PREPARED) is a multi-organizational project aimed at mainstreaming climate-resilient development planning and program implementation into the East African Community (EAC). The Famine Early Warning Systems Network (FEWS NET) has partnered with the PREPARED project to address three key development challenges for the EAC; 1) increasing resiliency to climate change, 2) managing trans-boundary freshwater biodiversity and conservation and 3) improving access to drinking water supply and sanitation services. USGS FEWS NET has been instrumental in the development of gridded climate data sets that are the fundamental building blocks for climate change adaptation studies in the region. Tools such as the Geospatial Climate Tool (GeoCLIM) have been developed to interpolate time-series grids of precipitation and temperature values from station observations and associated satellite imagery, elevation data, and other spatially continuous fields. The GeoCLIM tool also allows the identification of anomalies and assessments of both their frequency of occurrence and directional trends. A major effort has been put forth to build the capacities of local and regional institutions to use GeoCLIM to integrate their station data (which is not typically available to the public) into improved national and regional gridded climate data sets. In addition to the improvements and capacity building activities related to geospatial analysis tools, FEWS NET will assist in two other areas; 1) downscaling of climate change scenarios and 2) vulnerability impact assessments. FEWS NET will provide expertise in statistical downscaling of Global Climate Model output fields and work with regional institutions to assess results of other downscaling methods. Completion of a vulnerability impact assessment (VIA) involves the examination of sectoral consequences in identified climate "hot spots". FEWS NET

  16. HPV infection and EGFR activation/alteration in HIV-infected East African patients with conjunctival carcinoma.

    Directory of Open Access Journals (Sweden)

    Jing Jie Yu

    2010-05-01

    Full Text Available There has been substantial growth in the numbers of patients with conjunctival squamous cell carcinoma infected with HIV in East Africa. The natural history of the conjunctival squamous cell carcinoma appears to be unique in this region of the world, but the etiologic mechanism unclear and therapeutic options limited. This research was carried out to determine if conjunctival squamous cell carcinoma harbors human papillomavirus DNA and is associated with activation of the EGFR signaling pathway. Positive findings would identify etiologic causes and provide clinical guidance to improve treatment.Expression of p-MAPK/MAPK, p-Akt/Akt and p-EGFR/EGFR in cell nuclei and cytoplasm of 38 FFPE specimens were assessed by immunohistochemistry; HPV genotype was detected by qPCR assay; EGFR mutation was assessed by DNA sequencing analysis; and EGFR mRNA expression was measured using relative qPCR. Statistical analyses included two-sided Fisher exact test or chi-square test, Spearman correlation coefficient and ANOVA. HPV 18 was found in 61% of samples, with HPV 16 double-genotype in 6 patients (16%. Immunohistochemistry and qPCR data suggest that activation and expression of the EGFR signaling pathway is related to disease progression of conjunctival cancer. The associations between cytoplasmic p-MAPK, cytoplasmic p-Akt and tumor invasiveness were significant (p = 0.05 or 0.028. Nuclear p-EGFR appeared only in invasive tumors. A significant positive association between EGFR expression and disease invasiveness was observed (p = 0.01. A SNP in 10 patients and one missense mutation were found within EGFR tyrosine kinase domain. Statistical analysis indicates that patients with measurable EGFR expression more likely harbor EGFR mutations, compared to those with negative EGFR expression (35.3% vs. 0%.We conclude that HPV types 16/18 infection is frequent in East African patients with AIDS-associated squamous cell carcinoma of the conjunctiva. EGFR activation

  17. An MJO-Mediated Mechanism to Explain ENSO and IOD Impacts on East African Short Rains

    Science.gov (United States)

    Zaitchik, B. F.; Berhane, F.; Gnanadesikan, A.

    2015-12-01

    Previous studies have found that the El Nino Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) have significant impacts on rainfall over East Africa (EA) during the short rains (Oct-Dec). However, not all ENSO and IOD events are associated with significant precipitation anomalies over EA. Our analysis shows that the IOD and ENSO influence EA rainfall by modifying the MJO. Composite analysis of rainfall and outgoing longwave radiation data show that the MJO over the Indian Ocean (phases 2 and 3 of the Wheeler and Hendon index) is associated with significant increase in precipitation over EA during El Niño. In La Niña and non-ENSO years, the MJO over the Indian Ocean has very weak impacts on EA convection and precipitation. Although previous studies have found that El Niño / La Niña events are associated with anomalous wetness/dryness over EA, the associations are not evident in the absence of the MJO. Similarly, the IOD exhibits strong associations with EA precipitation when there is MJO activity over the Indian Ocean. During the positive phase of the IOD, the MJO over the Indian Ocean has impacts that extend to EA. In the absence of the MJO, however, the IOD shows weak associations with EA precipitation. Furthermore, there are more MJO days in the Indian Ocean during El Niño and positive IOD events, which implies stronger impacts on EA. During La Niña events more MJO days are observed in the Pacific Ocean, favoring subsidence over the western Indian Ocean and dry anomalies over EA. These observations suggest two critical MJO-related questions that must be addressed in order to explain EA short rain variability typically attributed to ENSO or IOD: first, how do ENSO and IOD modify background conditions in a way that causes Indian Ocean MJO activity to be more strongly connected to EA under El Niño and IOD positive conditions, and second, why is it that El Niño and IOD positive states slow MJO propagation over the Indian Ocean and speed it over

  18. East African Soil Erosion Recorded in a 300 Year old Coral Colony From Kenya

    Science.gov (United States)

    Dunbar, R. B.; Fleitmann, D.; McCulloch, M.; Mudelsee, M.; Vuille, M.; McClanahan, T.; Cole, J.; Eggins, S.

    2006-12-01

    Soil erosion threatens the food security of 2.6 billion people worldwide. The situation is particularly dire in East and Sub-Saharan Africa where per capita food production has declined over the past 45 years. Erosion and the resultant loss of fertile soil is a key socio-economic and ecological problem in Kenya, affecting all sectors of its economy and damaging marine and terrestrial ecosystems. The temporal pattern of soil erosion is almost unknown and currently only sparse and rather anecdotal information exists. To aid in filling this gap of knowledge, we present a 300-year long Barium record from two Kenyan coral colonies (Porites sp., 3°15'S, 40°9' E; Malindi Marine National Park) that documents a dynamic history of soil erosion in the Sabaki river drainage basin. To reconstruct Sabaki River sediment flux to the Malindi coral reef Ba/Ca ratios were measured in the skeleton of two Porites colonies (Mal 96-1 and Mal 95-3). Well-developed annual bands allow us to develop annually precise chronologies. Ba/Ca ratios were measured in core Mal 96-1 at continuous 40 μm intervals (~400 to 500 samples yr-1) using laser-ablation inductively coupled plasma mass spectrometry (LA- ICP-MS). To test for reproducibility and accuracy of the Mal 96-1 Ba/Ca profile, coral core Mal 95-3 was analyzed at lower resolution (1 to 12 samples yr-1) using discrete micro-drill sampling and isotope dilution ICP-MS. The close similarity between both coral Ba/Ca profiles, in absolute values as well as general pattern, underscores the accuracy of the LA-ICP-MS technique and adds confidence to our interpretation of the 300 year long Mal 96-1 Ba/Ca profile. The Ba/Ca coral proxy record shows that while the sediment flux from the Sabaki River is nearly constant between 1700 and 1900, a continuous rise in sediment flux is observed since 1900, reflecting steadily increasing demographic pressure on land use. The peak in suspended sediment load and hence soil erosion recorded at the Malindi reef

  19. Fate of redox-sensitive elements in two different East-African wetland systems

    Science.gov (United States)

    Glasner, Björn; Fiedler, Sabine

    2017-04-01

    We expect that an intensified cropping alters soil pH and Eh, and negatively affects the production potential of wetlands. Therefore, we investigated the redox-conditions in combination with the fate of different redox-sensitive elements in two prototypical wetland systems that show a high potential for food production in East-Africa. While the floodplains (observed near Ifakara, Kilombero District/Tanzania) serve as major crop producing areas in the region, the Inland Valleys (observed in Namulonge, Central District/Uganda) show a high potential for future production. Both systems have been divided into three positions; the fringe near to the slope, the center near to the river and the middle in between these two positions. In order to get a better understanding of the two systems we installed continuously measuring redox-electrodes in three different positions within both systems. Additionally, the fate of mineral elements was measured using ion-exchange resins with an installation period of 3-4 months. At the Tanzanian field sites the Eh-potential shows one major dry period with moderately reducing to well drained conditions in all sampling depths (10, 30, and 50 cm below ground) in all three positions during the measuring period from March 2015 to Dec 2016. Starting with the rains the Eh-potential drops from 700 mV (in 10 and 30 cm depth) to reducing conditions at all three sites - with intermediate brakes in the middle and fringe positions, showing that there has been no rain during these periods. At the Ugandan field sites the Eh-potential shows more fluctuations during the measuring period, especially in the center position in 2015 ( 750 to -200 mV in 30 and 50 cm depth). Having just the Eh-potential from the first 30 cm below ground it is not really possible to differentiate between dry- and rainy-seasons at the sites. The fate of redox-sensitive elements (Fe, Mn, and P) does not always correlate with the overall Eh-conditions (median) of the installation

  20. Tree-grass interactions in savannas

    CSIR Research Space (South Africa)

    Scholes, RJ

    1997-01-01

    Full Text Available Savannas occur where trees and grasses interact to create a biome that is neither grassland nor forest. Woody and gramineous plants interact by many mechanisms, some negative (competition) and some positive (facilitation). The strength and sign...

  1. Low-intensity violence and the social determinants of adolescent health among three East African pastoralist communities.

    Science.gov (United States)

    Pike, Ivy L; Hilton, Charles; Österle, Matthias; Olungah, Owuor

    2018-04-01

    Recently, strong pleas have emerged to place the health of adolescents on the global health agenda. To reposition adolescence front and center, scholars argue that we must work toward a richly contextualized approach that considers the role that social environments play in shaping the final stages of growth and development. We aim to contribute to this deeper understanding of the social determinants of global adolescent health by offering a case study of three nomadic pastoralist communities from northern Kenya. In addition to noteworthy political and economic marginalization, East African pastoralist communities also contend with chronic, low intensity intercommunity conflict. Data collected over five extensive visits from 2008 to 2011, include the 10-19 year olds from 215 randomly sampled Pokot, Samburu, and Turkana households. Using a case/control design, we sampled two sites per ethnic community: one directly affected and one less affected by intercommunity violence. Our nutritional findings indicate that teens ages 15-19 years old had significantly higher anthropometric values compared to younger teens. Living in a wealthier household is associated with greater height, body mass indices, and summed skinfolds for boys but not for girls. Anthropometric measures were influenced by household and community variation in the mixed-effects, multi-level regression models. The Self-Report Questionnaire (SRQ-20) was used to assess psychosocial health, with higher scores associated with living in a community directly affected by violence and having lost a loved one due to violence. Our findings highlight the unique nature of adolescent health challenges but also the central role even subtle differences across communities and households play in shaping young people's experiences. With few studies to document the lived experience of pastoralist youth as they move toward adulthood, examining how such challenging socioeconomic environment shapes health seems long overdue

  2. ICDP project DeepCHALLA: reconstructing East African climate change and environmental history over the past 250,000 years

    Science.gov (United States)

    Verschuren, Dirk; Van Daele, Maarten; Wolff, Christian; Waldmann, Nicolas; Meyer, Inka; Ombori, Titus; Peterse, Francien; O'Grady, Ryan; Schnurrenberger, Doug; Olago, Daniel

    2017-04-01

    Sediments on the bottom of Lake Challa, a 92-meter deep crater lake on the border of Kenya and Tanzania near Mt. Kilimanjaro, contain a uniquely long and continuous record of past climate and environmental change. The near-equatorial location and exceptional quality of this natural archive provide great opportunities to study tropical climate variability at both short (inter-annual to decadal) and long (glacial-interglacial) time scales; and the influence of this climate variability on the region's freshwater resources, the functioning of terrestrial ecosystems, and the history of the East African landscape in which modern humans (our species, Homo sapiens) evolved and have lived ever since. Supported in part by the International Continental Scientific Drilling Programme (ICDP), the DeepCHALLA project has now recovered the sediment record of Lake Challa down to 214.8 meter below the lake floor, with almost certain 100% cover of the uppermost 121.3 meter (ca.150,000 year BP to present) and estimated 85% cover over the lower part of the sequence, down to the lowermost distinct reflector in the available seismic stratigraphy. This reflector represents a 2 meter thick layer of volcanic sand and silt deposited ca.250,000 years ago, and overlies still older silty lacustrine clays deposited during early lake development. Down-hole logging produced continuous profiles of in-situ sediment composition that confer an absolute depth scale to both the recovered cores and their three-dimensional representation in seismic stratigraphy. As readily observed through the transparent core liners, Lake Challa sediments are finely laminated throughout most of the recovered sequence. Combined with the great time span, the exquisite temporal resolution of these sediments promises to greatly increase our understanding of tropical climate and ecosystem dynamics, and create a long-awaited equatorial counterpart to the high-latitude climate records extracted from the ice sheets of Greenland

  3. Meat Quality Characteristics of Small East African Goats and Norwegian Crosses Finished under Small Scale Farming Conditions.

    Science.gov (United States)

    Hozza, W A; Mtenga, L A; Kifaro, G C; Shija, D S N; Mushi, D E; Safari, J G; Shirima, E J M

    2014-12-01

    The aim of the experiment was to study the effect of feeding system on meat quality characteristics of Small East African (SEA) goats and their crosses with Norwegian (SEA×N) goats finished under small scale farming conditions. Twenty four castrated goats at the age of 18 months with live body weight of 16.7±0.54 kg from each breed (SEA and SEA×N) were distributed in a completely randomized design in a 2×3 factorial arrangement (two breed, and three dietary treatments). The dietary treatments were; no access to concentrate (T0), 66% access to ad libitum concentrate allowance (T66) and 100% access to ad libitum concentrate allowance with 20% refusal (T100) and the experimental period was for 84 days. In addition, all goats were allowed to graze for 2 hours daily and later fed grass hay on ad libitum basis. Daily feed intakes were recorded for all 84-days of experiment after which the animals were slaughtered. Feed intake of T100 animals was 536 g/d, which was 183 g/d higher than that of T66 group. Supplemented goats had significantly (p0.05) for dressing percentage and carcass conformation among supplemented goats except fatness score, total fat depots and carcass fat which increased (pgoats fed concentrate declined rapidly and reached below 6 at 6 h post-mortem but temperature remained at 28°C. Cooking loss and meat tenderness improved (pgoats and their crosses with Norwegian breeds finished under small scale farming conditions in rural areas. Therefore, concentrate supplementation of goats of both breeds improves meat quality attributes.

  4. Introduction of East African cassava mosaic Zanzibar virus to Oman harks back to "Zanzibar, the capital of Oman".

    Science.gov (United States)

    Khan, Akhtar J; Akhtar, Sohail; Al-Matrushi, Abdulrahman M; Fauquet, Claude M; Briddon, Rob W

    2013-02-01

    Cassava mosaic disease (CMD) is the most devastating disease of the subsistence crop cassava (Manihot esculenta) across Africa and the Indian subcontinent. The disease is caused by viruses of the genus Begomovirus (family Geminiviridae)-seven species have been identified so far. The Sultanate of Oman is unusual among countries in Arabia in growing cassava on a small scale for local consumption. During a recent survey in A'Seeb wilayat of Muscat governorate, Oman, cassava plants were identified with symptoms typical of CMD. A begomovirus, East African cassava mosaic Zanzibar virus (EACMZV), was isolated from symptomatic plants. This virus was previously only known to occur in Zanzibar and Kenya. During the 19th Century, Zanzibar was governed by Oman and was so important that the Sultan of Oman moved his capital there from Muscat. After a period of colonial rule, the governing Arab elite was overthrown, following independence in the 1960s, and many expatriate Omanis returned to their homeland. Having gained a liking for the local Zanzibar cuisine, it appears that returning Omanis did not wish to do without dishes made from one particular favorite, cassava. Consequently, they carried planting material back to Oman for cultivation in their kitchen gardens. The evidence suggests that this material harbored EACMZV. Recently, Oman has been shown to be a nexus for geminiviruses and their associated satellites from diverse geographic origins. With their propensity to recombine, a major mechanism for evolution of geminiviruses, and the fact that Oman (and several other Arabian countries) is a major hub for trade and travel by air and sea, the possibility of onward spread is worrying.

  5. Sexual learning among East African adolescents in the context of generalized HIV epidemics: A systematic qualitative meta-synthesis.

    Directory of Open Access Journals (Sweden)

    Amelia S Knopf

    Full Text Available AIDS-related illness is the leading cause of mortality for adolescents in sub-Saharan Africa. Together, Kenya, Tanzania, and Uganda account for 21% of HIV-infected adolescents in sub-Saharan Africa. The United Nations framework for addressing the epidemic among adolescents calls for comprehensive sexual and reproductive health education. These HIV prevention efforts could be informed by a synthesis of existing research about the formal and informal sexual education of adolescents in countries experiencing generalized epidemics. The purpose of this study was to describe the process of sexual learning among East African adolescents living in the context of generalized HIV epidemics.Qualitative metasynthesis, a systematic procedure for integrating the results of multiple qualitative studies addressing a similar phenomenon, was used. Thirty-two research reports met study inclusion criteria. The reports were assessed in a four-step analytic process: appraisal, classification of findings, synthesis of findings, and construction of a framework depicting the process of sexual learning in this population.The framework includes three phases of sexual learning: 1 being primed for sex, 2 making sense of sex, and 3 having sexual experiences. Adolescents were primed for sex through gender norms, cultural practices, and economic structures as well as through conversations and formal instruction. They made sense of sex by acquiring information about sexual intercourse, reproduction and pregnancy, sexually transmitted infections, and relationships and by developing a variety of beliefs and attitudes about these topics. Some adolescents described having sexual experiences that met wants or needs, but many experienced sex that was coerced or violent. Whether sex was wanted, coerced, or violent, adolescents experienced worry about sexually transmitted infections or premarital pregnancy.The three phases of sexual learning interact to shape adolescents' sexual lives

  6. Mapping Cropland in Smallholder-Dominated Savannas: Integrating Remote Sensing Techniques and Probabilistic Modeling

    Directory of Open Access Journals (Sweden)

    Sean Sweeney

    2015-11-01

    Full Text Available Traditional smallholder farming systems dominate the savanna range countries of sub-Saharan Africa and provide the foundation for the region’s food security. Despite continued expansion of smallholder farming into the surrounding savanna landscapes, food insecurity in the region persists. Central to the monitoring of food security in these countries, and to understanding the processes behind it, are reliable, high-quality datasets of cultivated land. Remote sensing has been frequently used for this purpose but distinguishing crops under certain stages of growth from savanna woodlands has remained a major challenge. Yet, crop production in dryland ecosystems is most vulnerable to seasonal climate variability, amplifying the need for high quality products showing the distribution and extent of cropland. The key objective in this analysis is the development of a classification protocol for African savanna landscapes, emphasizing the delineation of cropland. We integrate remote sensing techniques with probabilistic modeling into an innovative workflow. We present summary results for this methodology applied to a land cover classification of Zambia’s Southern Province. Five primary land cover categories are classified for the study area, producing an overall map accuracy of 88.18%. Omission error within the cropland class is 12.11% and commission error 9.76%.

  7. Content of a novel online collection of traditional east African food habits (1930s-1960s): data collected by the Max-Planck-Nutrition Research Unit, Bumbuli, Tanzania.

    Science.gov (United States)

    Raschke, Verena; Oltersdorf, Ulrich; Elmadfa, Ibrahim; Wahlqvist, Mark L; Cheema, Birinder Sb; Kouris-Blazos, Antigone

    2007-01-01

    Knowledge of traditional African foods and food habits has been, and continues to be, systematically extirpated. With the primary intent of collating data for our online collection documenting traditional African foods and food habits (available at: www.healthyeatingclub.com/Africa/), we reviewed the Oltersdorf Collection, 75 observational investigations conducted throughout East Africa (i.e. Tanzania, Kenya, and Uganda) between the 1930s and 1960s as compiled by the Max Planck Nutrition Research Unit, formerly located in Bumbuli, Tanzania. Data were categorized as follows: (1) food availability, (2) chemical composition, (3) staple foods (i.e. native crops, cereals, legumes, roots and tubers, vegetables, fruits, spices, oils and fats, beverages, and animal foods), (4) food preparation and culture, and (5) nutrient intake and health status indicators. Many of the traditional foods identified, including millet, sorghum, various legumes, root and tubers, green leafy vegetables, plant oils and wild meats have known health benefits. Food preparatory practices during this period, including boiling and occasional roasting are superior to current practices which favor frying and deep-frying. Overall, our review and data extraction provide reason to believe that a diversified diet was possible for the people of East Africa during this period (1930s-1960s). There is a wealth of knowledge pertaining to traditional East African foods and food habits within the Oltersdorf Collection. These data are currently available via our online collection. Future efforts should contribute to collating and honing knowledge of traditional foods and food habits within this region, and indeed throughout the rest of Africa. Preserving and disseminating this knowledge may be crucial for abating projected trends for non-communicable diseases and malnutrition in Africa and abroad.

  8. Equality in Maternal and Newborn Health: Modelling Geographic Disparities in Utilisation of Care in Five East African Countries.

    Directory of Open Access Journals (Sweden)

    Corrine W Ruktanonchai

    Full Text Available Geographic accessibility to health facilities represents a fundamental barrier to utilisation of maternal and newborn health (MNH services, driving historically hidden spatial pockets of localized inequalities. Here, we examine utilisation of MNH care as an emergent property of accessibility, highlighting high-resolution spatial heterogeneity and sub-national inequalities in receiving care before, during, and after delivery throughout five East African countries.We calculated a geographic inaccessibility score to the nearest health facility at 300 x 300 m using a dataset of 9,314 facilities throughout Burundi, Kenya, Rwanda, Tanzania and Uganda. Using Demographic and Health Surveys data, we utilised hierarchical mixed effects logistic regression to examine the odds of: 1 skilled birth attendance, 2 receiving 4+ antenatal care visits at time of delivery, and 3 receiving a postnatal health check-up within 48 hours of delivery. We applied model results onto the accessibility surface to visualise the probabilities of obtaining MNH care at both high-resolution and sub-national levels after adjusting for live births in 2015.Across all outcomes, decreasing wealth and education levels were associated with lower odds of obtaining MNH care. Increasing geographic inaccessibility scores were associated with the strongest effect in lowering odds of obtaining care observed across outcomes, with the widest disparities observed among skilled birth attendance. Specifically, for each increase in the inaccessibility score to the nearest health facility, the odds of having skilled birth attendance at delivery was reduced by over 75% (0.24; CI: 0.19-0.3, while the odds of receiving antenatal care decreased by nearly 25% (0.74; CI: 0.61-0.89 and 40% for obtaining postnatal care (0.58; CI: 0.45-0.75.Overall, these results suggest decreasing accessibility to the nearest health facility significantly deterred utilisation of all maternal health care services. These

  9. Deriving spatial patterns from a novel database of volcanic rock geochemistry in the Virunga Volcanic Province, East African Rift

    Science.gov (United States)

    Poppe, Sam; Barette, Florian; Smets, Benoît; Benbakkar, Mhammed; Kervyn, Matthieu

    2016-04-01

    The Virunga Volcanic Province (VVP) is situated within the western branch of the East-African Rift. The geochemistry and petrology of its' volcanic products has been studied extensively in a fragmented manner. They represent a unique collection of silica-undersaturated, ultra-alkaline and ultra-potassic compositions, displaying marked geochemical variations over the area occupied by the VVP. We present a novel spatially-explicit database of existing whole-rock geochemical analyses of the VVP volcanics, compiled from international publications, (post-)colonial scientific reports and PhD theses. In the database, a total of 703 geochemical analyses of whole-rock samples collected from the 1950s until recently have been characterised with a geographical location, eruption source location, analytical results and uncertainty estimates for each of these categories. Comparative box plots and Kruskal-Wallis H tests on subsets of analyses with contrasting ages or analytical methods suggest that the overall database accuracy is consistent. We demonstrate how statistical techniques such as Principal Component Analysis (PCA) and subsequent cluster analysis allow the identification of clusters of samples with similar major-element compositions. The spatial patterns represented by the contrasting clusters show that both the historically active volcanoes represent compositional clusters which can be identified based on their contrasted silica and alkali contents. Furthermore, two sample clusters are interpreted to represent the most primitive, deep magma source within the VVP, different from the shallow magma reservoirs that feed the eight dominant large volcanoes. The samples from these two clusters systematically originate from locations which 1. are distal compared to the eight large volcanoes and 2. mostly coincide with the surface expressions of rift faults or NE-SW-oriented inherited Precambrian structures which were reactivated during rifting. The lava from the Mugogo

  10. Equality in Maternal and Newborn Health: Modelling Geographic Disparities in Utilisation of Care in Five East African Countries.

    Science.gov (United States)

    Ruktanonchai, Corrine W; Ruktanonchai, Nick W; Nove, Andrea; Lopes, Sofia; Pezzulo, Carla; Bosco, Claudio; Alegana, Victor A; Burgert, Clara R; Ayiko, Rogers; Charles, Andrew Sek; Lambert, Nkurunziza; Msechu, Esther; Kathini, Esther; Matthews, Zoë; Tatem, Andrew J

    2016-01-01

    Geographic accessibility to health facilities represents a fundamental barrier to utilisation of maternal and newborn health (MNH) services, driving historically hidden spatial pockets of localized inequalities. Here, we examine utilisation of MNH care as an emergent property of accessibility, highlighting high-resolution spatial heterogeneity and sub-national inequalities in receiving care before, during, and after delivery throughout five East African countries. We calculated a geographic inaccessibility score to the nearest health facility at 300 x 300 m using a dataset of 9,314 facilities throughout Burundi, Kenya, Rwanda, Tanzania and Uganda. Using Demographic and Health Surveys data, we utilised hierarchical mixed effects logistic regression to examine the odds of: 1) skilled birth attendance, 2) receiving 4+ antenatal care visits at time of delivery, and 3) receiving a postnatal health check-up within 48 hours of delivery. We applied model results onto the accessibility surface to visualise the probabilities of obtaining MNH care at both high-resolution and sub-national levels after adjusting for live births in 2015. Across all outcomes, decreasing wealth and education levels were associated with lower odds of obtaining MNH care. Increasing geographic inaccessibility scores were associated with the strongest effect in lowering odds of obtaining care observed across outcomes, with the widest disparities observed among skilled birth attendance. Specifically, for each increase in the inaccessibility score to the nearest health facility, the odds of having skilled birth attendance at delivery was reduced by over 75% (0.24; CI: 0.19-0.3), while the odds of receiving antenatal care decreased by nearly 25% (0.74; CI: 0.61-0.89) and 40% for obtaining postnatal care (0.58; CI: 0.45-0.75). Overall, these results suggest decreasing accessibility to the nearest health facility significantly deterred utilisation of all maternal health care services. These results

  11. East African Orthopaedic Journal

    African Journals Online (AJOL)

    Anthropometry of the distal femur in a Kenyan population and its correlation with total knee replacement implants · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. K.C. Lakati, B.M. Ndeleva, C.K. Kibet, S.M. Odhiambo, V.B. Sokobe, 67-72 ...

  12. East African Medical Journal

    African Journals Online (AJOL)

    REpORTINg ON MENTAl HEAlTH IllNESS (MHI) IN KENyA: HOw wEll ARE. wE dOINg? ... fundamental for evidence-based decision-making and improved service ... Owiti, MBChB, MSc, Academic Model for Prevention and Treatment of HIV ...

  13. East African Medical Journal

    African Journals Online (AJOL)

    2009-09-09

    Sep 9, 2009 ... PREGNANCY RATES AMONG FEMALE PARTICIPANTS IN PHASE I AND PHASE IIA AIDS VACCINE CLINICAL. TRIALS ..... for mothers, domestic workers and sex workers .... consultants of IAVI, the funding organisation and.

  14. East African Medical Journal

    African Journals Online (AJOL)

    F. M. Gakuya, BVM, MSc, M.N.Kyule, BVM, MSc, PhD, P.B. Gathura, BVM, MSc, PhD, Department of Public Health, Pharmacology and Toxicology, University of. Nairobi, P.O. Box 29053, Nairobi, Kenya and S. Kariuki, BVM, MSc, PhD, CentreforMicrobiology Research, Kenya Medical Research Institute, P.O. Box54840, ...

  15. East African Medical Journal

    African Journals Online (AJOL)

    (CHWs) to promote WASH practices and to collect household based data using a structured reporting tool. ... are encouraged to purchase from local shops. Hand washing ... Ethics Review Board of Médecins Sans Frontières,. Luxembourg.

  16. East African Medical Journal

    African Journals Online (AJOL)

    2002-07-01

    Jul 1, 2002 ... PREVALENCE OF VITAMIN A DEFICIENCY AMONG PRE-SCHOOL AND SCHOOL-AGED CHILDREN IN ARSSI ZONE. ETHIOPIA. YT Asrat, BSc. MSc ... in the “low” range (<20ttl/dl) in 51% of the children. Conclusion: The results ... of Arssi zone Dodotana Sire district was selected at random for this study.

  17. East African Medical Journal

    African Journals Online (AJOL)

    2007-11-11

    Nov 11, 2007 ... Kenyatta National Hospital, Nairobi Women's. Hospital, Coast ... standard Karl Storz tower consisting of two 15 inch flat ... The carbon dioxide insufflation pressure was ..... complications, took longer to perform and were offset.

  18. East African cassava mosaic-like viruses from Africa to Indian ocean islands: molecular diversity, evolutionary history and geographical dissemination of a bipartite begomovirus

    Directory of Open Access Journals (Sweden)

    De Bruyn Alexandre

    2012-11-01

    Full Text Available Abstract Background Cassava (Manihot esculenta is a major food source for over 200 million sub-Saharan Africans. Unfortunately, its cultivation is severely hampered by cassava mosaic disease (CMD. Caused by a complex of bipartite cassava mosaic geminiviruses (CMG species (Family: Geminivirideae; Genus: Begomovirus CMD has been widely described throughout Africa and it is apparent that CMG's are expanding their geographical distribution. Determining where and when CMG movements have occurred could help curtail its spread and reveal the ecological and anthropic factors associated with similar viral invasions. We applied Bayesian phylogeographic inference and recombination analyses to available and newly described CMG sequences to reconstruct a plausible history of CMG diversification and migration between Africa and South West Indian Ocean (SWIO islands. Results The isolation and analysis of 114 DNA-A and 41 DNA-B sequences demonstrated the presence of three CMG species circulating in the Comoros and Seychelles archipelagos (East African cassava mosaic virus, EACMV; East African cassava mosaic Kenya virus, EACMKV; and East African cassava mosaic Cameroon virus, EACMCV. Phylogeographic analyses suggest that CMG’s presence on these SWIO islands is probably the result of at least four independent introduction events from mainland Africa occurring between 1988 and 2009. Amongst the islands of the Comoros archipelago, two major migration pathways were inferred: One from Grande Comore to Mohéli and the second from Mayotte to Anjouan. While only two recombination events characteristic of SWIO islands isolates were identified, numerous re-assortments events were detected between EACMV and EACMKV, which seem to almost freely interchange their genome components. Conclusions Rapid and extensive virus spread within the SWIO islands was demonstrated for three CMG complex species. Strong evolutionary or ecological interaction between CMG species may explain

  19. African Journals Online (AJOL)

    African Journals Online (AJOL)

    African Journals OnLine (AJOL) is the world's largest and pre-eminent collection of peer-reviewed, African-published scholarly journals. Historically, scholarly information has flowed from North to South and from West to East. It has also been difficult for African researchers to access the work of other African academics.

  20. Restoration of midwestern oak woodlands and savannas

    Science.gov (United States)

    Dan C. Dey; John M. Kabrick

    2015-01-01

    There are various definitions for savanna and woodland in the ecological literature. Characteristic elements of each community are broadly defined and often overlap according to the authorities (Curtis 1959; Nuzzo 1986; Nelson 2010). Some confusion is inevitable when categorizing what is in reality a continuum of states from prairie to forest in which there can be much...

  1. Oak savanna restoration in central Iowa: Assessing indicators of forest health for ecological monitoring (PROJECT NC-F-04-02)

    Science.gov (United States)

    Heidi Asbjornsen; Lars Brudvig

    2013-01-01

    Savanna ecosystems were once a dominant feature of the Midwestern Corn Belt Plains ecoregion, occurring within the dynamic boundary between prairies to the west and forests to the east, and maintained in the landscape by complex interactions between fire, climate, topography, and human activities (Anderson 1998). Characterized by their continuous understory layer and...

  2. Precipitation chemistry and wet deposition in a remote wet savanna site in West Africa: Djougou (Benin)

    Science.gov (United States)

    Akpo, A. B.; Galy-Lacaux, C.; Laouali, D.; Delon, C.; Liousse, C.; Adon, M.; Gardrat, E.; Mariscal, A.; Darakpa, C.

    2015-08-01

    In the framework of the IDAF (IGAC/DEBITS/AFrica) international program, this study aims to study the chemical composition of precipitation and associated wet deposition at the rural site of Djougou in Benin, representative of a West and Central African wet savanna. Five hundred and thirty rainfall samples were collected at Djougou, Benin, from July 2005 to December 2009 to provide a unique database. The chemical composition of precipitation was analyzed for inorganic (Ca2+, Mg2+, Na+, NH4+, K+, NO3-, Cl-, SO42-) and organic (HCOO-, CH3COO-, C2H5COO-, C2O42-) ions, using ion chromatography. The 530 collected rain events represent a total of 5706.1 mm of rainfall compared to the measured pluviometry 6138.9 mm, indicating that the collection efficiency is about 93%. The order of total annual loading rates for soluble cations is NH4+ > Ca2+ > Mg2+ > K+. For soluble anions the order of loading is carbonates > HCOO- > NO3- > CH3COO- > SO42- > Cl- > C2O42- > C2H5COO-. In the wet savanna of Djougou, 86% of the measured pH values range between 4.7 and 5.7 with a median pH of 5.19, corresponding to a VWM (Volume Weighed Mean) H+ concentration of 6.46 μeq·L-1. This acidity results from a mixture of mineral and organic acids. The annual sea salt contribution was computed for K+, Mg2+, Ca2+ and SO42- and represents 4.2% of K+, 41% of Mg2+, 1.3% of Ca2+, and 7.4% of SO42-. These results show that K+, Ca2+, SO42-, and Mg2+ were mainly of non-marine origin. The marine contribution is estimated at 9%. The results of the chemical composition of rainwater of Djougou indicates that, except for the carbonates, ammonium has the highest VWM concentration (14.3 μeq·L-1) and nitrate concentration is 8.2 μeq·L-1. The distribution of monthly VWM concentration for all ions is computed and shows the highest values during the dry season, comparing to the wet season. Identified nitrogenous compound sources (NOx and NH3) are domestic animals, natural emissions from savanna soils, biomass

  3. Genomic footprints of dryland stress adaptation in Egyptian fat-tail sheep and their divergence from East African and western Asia cohorts.

    Science.gov (United States)

    Mwacharo, Joram M; Kim, Eui-Soo; Elbeltagy, Ahmed R; Aboul-Naga, Adel M; Rischkowsky, Barbara A; Rothschild, Max F

    2017-12-15

    African indigenous sheep are classified as fat-tail, thin-tail and fat-rump hair sheep. The fat-tail are well adapted to dryland environments, but little is known on their genome profiles. We analyzed patterns of genomic variation by genotyping, with the Ovine SNP50K microarray, 394 individuals from five populations of fat-tail sheep from a desert environment in Egypt. Comparative inferences with other East African and western Asia fat-tail and European sheep, reveal at least two phylogeographically distinct genepools of fat-tail sheep in Africa that differ from the European genepool, suggesting separate evolutionary and breeding history. We identified 24 candidate selection sweep regions, spanning 172 potentially novel and known genes, which are enriched with genes underpinning dryland adaptation physiology. In particular, we found selection sweeps spanning genes and/or pathways associated with metabolism; response to stress, ultraviolet radiation, oxidative stress and DNA damage repair; activation of immune response; regulation of reproduction, organ function and development, body size and morphology, skin and hair pigmentation, and keratinization. Our findings provide insights on the complexity of genome architecture regarding dryland stress adaptation in the fat-tail sheep and showcase the indigenous stocks as appropriate genotypes for adaptation planning to sustain livestock production and human livelihoods, under future climates.

  4. Savanna fire and the origins of the 'underground forests' of Africa.

    Science.gov (United States)

    Maurin, Olivier; Davies, T Jonathan; Burrows, John E; Daru, Barnabas H; Yessoufou, Kowiyou; Muasya, A Muthama; van der Bank, Michelle; Bond, William J

    2014-10-01

    The origin of fire-adapted lineages is a long-standing question in ecology. Although phylogeny can provide a significant contribution to the ongoing debate, its use has been precluded by the lack of comprehensive DNA data. Here, we focus on the 'underground trees' (=geoxyles) of southern Africa, one of the most distinctive growth forms characteristic of fire-prone savannas. We placed geoxyles within the most comprehensive dated phylogeny for the regional flora comprising over 1400 woody species. Using this phylogeny, we tested whether African geoxyles evolved concomitantly with those of the South American cerrado and used their phylogenetic position to date the appearance of humid savannas. We found multiple independent origins of the geoxyle life-form mostly from the Pliocene, a period consistent with the origin of cerrado, with the majority of divergences occurring within the last 2 million yr. When contrasted with their tree relatives, geoxyles occur in regions characterized by higher rainfall and greater fire frequency. Our results indicate that the geoxylic growth form may have evolved in response to the interactive effects of frequent fires and high precipitation. As such, geoxyles may be regarded as markers of fire-maintained savannas occurring in climates suitable for forests. © 2014 The Authors New Phytologist © 2014 New Phytologist Trust.

  5. Genomic DNA sequences from mastodon and woolly mammoth reveal deep speciation of forest and savanna elephants.

    Directory of Open Access Journals (Sweden)

    Nadin Rohland

    2010-12-01

    Full Text Available To elucidate the history of living and extinct elephantids, we generated 39,763 bp of aligned nuclear DNA sequence across 375 loci for African savanna elephant, African forest elephant, Asian elephant, the extinct American mastodon, and the woolly mammoth. Our data establish that the Asian elephant is the closest living relative of the extinct mammoth in the nuclear genome, extending previous findings from mitochondrial DNA analyses. We also find that savanna and forest elephants, which some have argued are the same species, are as or more divergent in the nuclear genome as mammoths and Asian elephants, which are considered to be distinct genera, thus resolving a long-standing debate about the appropriate taxonomic classification of the African elephants. Finally, we document a much larger effective population size in forest elephants compared with the other elephantid taxa, likely reflecting species differences in ancient geographic structure and range and differences in life history traits such as variance in male reproductive success.

  6. Radiation absorption and use by humid savanna grassland: assessment using remote sensing and modelling

    International Nuclear Information System (INIS)

    Roux, X. le; Gauthier, H.; Begue, A.; Sinoquet, H.

    1997-01-01

    The components of the canopy radiation balance in photosynthetically active radiation (PAR), phytomass and leaf area index (LAI) were measured during a complete annual cycle in an annually burned African humid savanna. Directional reflectances measured by a hand-held radiometer were used to compute the canopy normalized difference vegetation index (NDVI). The fraction f APAR of PAR absorbed by the canopy (APAR) and canopy reflectances were simulated by the scattering from arbitrarily inclined leaves (SAIL) and the radiation interception in row intercropping (RIRI) models. The daily PAR to solar radiation ratio was linearly related to the daily fraction of diffuse solar radiation with an annual value around 0.47. The observed f APAR was non-linearly related to NDVI. The SAIL model simulated reasonably well directional reflectances but noticeably overestimated f APAR during most of the growing season. Comparison of simulations performed with the 1D and 3D versions of the RIRI model highlighted the weak influence of the heterogeneous structure of the canopy after fire and of the vertical distribution of dead and green leaves on total f APAR . Daily f APAR values simulated by the 3D-RIRI model were linearly related to and 9.8% higher than observed values. For sufficient soil water availability, the net production efficiency ϵ n of the savanna grass canopy was 1.92 and 1.28 g DM MJ −1 APAR (where DM stands for dry matter) during early regrowth and mature stage, respectively. In conclusion, the linear relationship between NDVI and f APAR used in most primary production models operating at large scales may slightly overestimate f APAR by green leaves for the humid savanna biome. Moreover, the net production efficiency of humid savannas is close to or higher than values reported for the other major natural biomes. (author)

  7. Youth citizenship, national unity and poverty alleviation: East and West African approaches to the education of a new generation

    OpenAIRE

    Arnot, Madeleine; Casely-Hayford, Leslie; Wainaina, Paul K.; Chege, Fatuma; Dovie, Delali A.

    2009-01-01

    Youth citizenship is now on the international agenda. This paper explores what that concept might mean in the context of two African nations: Kenya and Ghana. Post independence, both countries focused on rethinking the colonial concept of citizenship in line with their political-cultural traditions, providing education for all youth and to encouraging new notions of national citizenship. Programmes for civic education were established that have been reshaped over the last fifty years. These c...

  8. GEOTHERM programme supports geothermal energy world-wide. Geothermal energy, a chance for East African countries; GEOTHERM: BGR foerdert weltweit Nutzung geothermischer Energie. Geothermie - eine Chance fuer ostafrikanische Laender

    Energy Technology Data Exchange (ETDEWEB)

    Kraml, M.; Kessels, K.; Kalberkamp, U.; Ochmann, N.; Stadtler, C. [Bundesanstalt fuer Geowissenschaften und Rohstoffe (BGR), Hannover (Germany)

    2007-02-15

    The high geothermal potential of East Africa, especially of the Eastern Rift, is known for a long time. Since these pioneer studies, geothermal plants have been constructed at three sites in East Africa. Nevertheless, up to now geothermal has been a success story only in Kenya. The steam power plant Olkaria I in Kenya is running reliability since 25 years. Today, the country produces more than 12% of its electricity from geothermal. Now, Eritrea, Djibouti, Uganda, Tanzania and Ethiopia which are also situated along the East African Rift, are planning similar projects. The countries need to develop new energy sources because oil prices have reached a critical level. In the past, hydro power was regarded to be a reliable source of energy, but increased droughts changed the situation. Thus, the african states are searching for alternatives to be able to stabilise their energy supply and to cover the growing energy demand. There is much hope that the success of the Kenyan geothermal power plants will be repeated in the neighbouring countries. The East African countries have joined their forces to give impetus to the use of the regional geothermal resources. On behalf of the Federal Ministry for Economic Cooperation and Development, the Federal Institute for Geosciences and Natural Resources supports the countries in realising their plans as part of the GEOTHERM Programme. Together with further donors (Iceland, France, USA, Global Environment Facility) the path will be paved for geothermal power plants in the above mentioned six East African countries. The following main steps are necessary: - Awareness raising of political decision makers about the advantages of including geothermal into the national power plans - Improvement of knowledge about potentials geothermal sites - Development of a regional equipment pool including the necessary geophysical equipment, laboratories, etc. - Training in geothermal exploration and plant maintenance, to minimise risks of site

  9. African Journals Online (AJOL)

    African Journals Online (AJOL)

    reviewed, African-published scholarly journals. Historically, scholarly information has flowed from North to South and from West to East. It has also been difficult for African researchers to access the work of other African academics. In partnership with ...

  10. Molecular markers of anti-malarial drug resistance in Central, West and East African children with severe malaria

    OpenAIRE

    Nguetse, Christian N.; Adegnika, Ayola Akim; Agbenyega, Tsiri; Ogutu, Bernhards R.; Krishna, Sanjeev; Kremsner, Peter G.; Velavan, Thirumalaisamy P.

    2017-01-01

    BACKGROUND: The Plasmodium falciparum multidrug resistance 1 (PfMDR1), P. falciparum Ca(2+)-ATPase (PfATP6) and Kelch-13 propeller domain (PfK13) loci are molecular markers of parasite susceptibility to anti-malarial drugs. Their frequency distributions were determined in the isolates collected from children with severe malaria originating from three African countries. METHODS: Samples from 287 children with severe malaria [(Gabon: n = 114); (Ghana: n = 89); (Kenya: n = 84)] were genotyped fo...

  11. Geology and metallogeny of the Ar Rayn terrane, eastern Arabian shield: Evolution of a Neoproterozoic continental-margin arc during assembly of Gondwana within the East African orogen

    Science.gov (United States)

    Doebrich, J.L.; Al-Jehani, A. M.; Siddiqui, A.A.; Hayes, T.S.; Wooden, J.L.; Johnson, P.R.

    2007-01-01

    characteristics of the Ar Rayn terrane are analogous to the Andean continental margin of Chile, with opposite subduction polarity. The Ar Rayn terrane represents a continental margin arc that lay above a west-dipping subduction zone along a continental block represented by the Afif composite terrane. The concentration of epithermal, porphyry Cu and IOCG mineral systems, of central arc affiliation, along the AAF suggests that the AAF is not an ophiolitic suture zone, but originated as a major intra-arc fault that localized magmatism and mineralization. West-directed oblique subduction and ultimate collision with a land mass from the east (East Gondwana?) resulted in major transcurrent displacement along the AAF, bringing the eastern part of the arc terrane to its present exposed position, juxtaposed across the AAF against a back-arc basin assemblage represented by the Abt schist of the Ad Dawadimi terrane. Our findings indicate that arc formation and accretionary processes in the Arabian shield were still ongoing into the latest Neoproterozoic (Ediacaran), to about 620-600 Ma, and lead us to conclude that evolution of the Ar Rayn terrane (arc formation, accretion, syn- to postorogenic plutonism) defines a final stage of assembly of the Gondwana supercontinent along the northeastern margin of the East African orogen. ?? 2007 Elsevier B.V. All rights reserved.

  12. Land - Ocean Climate Linkages and the Human Evolution - New ICDP and IODP Drilling Initiatives in the East African Rift Valley and SW Indian Ocean

    Science.gov (United States)

    Zahn, R.; Feibel, C.; Co-Pis, Icdp/Iodp

    2009-04-01

    The past 5 Ma were marked by systematic shifts towards colder climates and concomitant reorganizations in ocean circulation and marine heat transports. Some of the changes involved plate-tectonic shifts such as the closure of the Panamanian Isthmus and restructuring of the Indonesian archipelago that affected inter-ocean communications and altered the world ocean circulation. These changes induced ocean-atmosphere feedbacks with consequences for climates globally and locally. Two new ICDP and IODP drilling initiatives target these developments from the perspectives of marine and terrestrial palaeoclimatology and the human evolution. The ICDP drilling initiative HSPDP ("Hominid Sites and Paleolakes Drilling Project"; ICDP ref. no. 10/07) targets lacustrine depocentres in Ethiopia (Hadar) and Kenya (West Turkana, Olorgesailie, Magadi) to retrieve sedimentary sequences close to the places and times where various species of hominins lived over currently available outcrop records. The records will provide a spatially resolved record of the East African environmental history in conjunction with climate variability at orbital (Milankovitch) and sub-orbital (ENSO decadal) time scales. HSPDP specifically aims at (1) compiling master chronologies for outcrops around each of the depocentres; (2) assessing which aspects of the paleoenvironmental records are a function of local origin (hydrology, hydrogeology) and which are linked with regional or larger-scale signals; (3) correlating broad-scale patterns of hominin phylogeny with the global beat of climate variability and (4) correlating regional shifts in the hominin fossil and archaeological record with more local patterns of paleoenvironmental change. Ultimately the aim is to test hypotheses that link physical and cultural adaptations in the course of the hominin evolution to local environmental change and variability. The IODP initiative SAFARI ("Southern African Climates, Agulhas Warm Water Transports and Retroflection

  13. Crustal and mantle structure and anisotropy beneath the incipient segments of the East African Rift System: Preliminary results from the ongoing SAFARI

    Science.gov (United States)

    Yu, Y.; Reed, C. A.; Gao, S. S.; Liu, K. H.; Massinque, B.; Mdala, H. S.; moidaki, M.; Mutamina, D. M.; Atekwana, E. A.; Ingate, S. F.; Reusch, A.; Barstow, N.

    2013-12-01

    Despite the vast wealth of research conducted toward understanding processes associated with continental rifting, the extent of our knowledge is derived primarily from studies focused on mature rift systems, such as the well-developed portions of the East African Rift System (EARS) north of Lake Malawi. To explore the dynamics of early rift evolution, the SAFARI (Seismic Arrays for African Rift Initiation) team deployed 50 PASSCAL broadband seismic stations across the Malawi, Luangwa, and Okavango rifts of the EARS during the summer of 2012. The cumulative length of the profiles is about 2500 km and the planned recording duration is 2 years. Here we present the preliminary results of systematic analyses of data obtained from the first year of acquisition for all 50 stations. A total of 446 high-quality shear-wave splitting measurements using PKS, SKKS, and SKS phases from 84 teleseismic events were used to constrain fast polarization directions and splitting times throughout the region. The Malawi and Okavango rifts are characterized by mostly NE trending fast directions with a mean splitting time of about 1 s. The fast directions on the west side of the Luangwa Rift Zone are parallel to the rift valley, and those on the east side are more N-S oriented. Stacking of approximately 1900 radial receiver functions reveals significant spatial variations of both crustal thickness and the ratio of crustal P and S wave velocities, as well as the thickness of the mantle transition zone. Stations situated within the Malawi rift demonstrate a southward increase in observed crustal thickness, which is consistent with the hypothesis that the Malawi rift originated at the northern end of the rift system and propagated southward. Both the Okavango and Luangwa rifts are associated with thinned crust and increased Vp/Vs, although additional data is required at some stations to enhance the reliability of the observations. Teleseismic P-wave travel-time residuals show a delay of about

  14. Fire in Australian savannas: from leaf to landscape

    Science.gov (United States)

    Beringer, Jason; Hutley, Lindsay B; Abramson, David; Arndt, Stefan K; Briggs, Peter; Bristow, Mila; Canadell, Josep G; Cernusak, Lucas A; Eamus, Derek; Edwards, Andrew C; Evans, Bradley J; Fest, Benedikt; Goergen, Klaus; Grover, Samantha P; Hacker, Jorg; Haverd, Vanessa; Kanniah, Kasturi; Livesley, Stephen J; Lynch, Amanda; Maier, Stefan; Moore, Caitlin; Raupach, Michael; Russell-Smith, Jeremy; Scheiter, Simon; Tapper, Nigel J; Uotila, Petteri

    2015-01-01

    Savanna ecosystems comprise 22% of the global terrestrial surface and 25% of Australia (almost 1.9 million km2) and provide significant ecosystem services through carbon and water cycles and the maintenance of biodiversity. The current structure, composition and distribution of Australian savannas have coevolved with fire, yet remain driven by the dynamic constraints of their bioclimatic niche. Fire in Australian savannas influences both the biophysical and biogeochemical processes at multiple scales from leaf to landscape. Here, we present the latest emission estimates from Australian savanna biomass burning and their contribution to global greenhouse gas budgets. We then review our understanding of the impacts of fire on ecosystem function and local surface water and heat balances, which in turn influence regional climate. We show how savanna fires are coupled to the global climate through the carbon cycle and fire regimes. We present new research that climate change is likely to alter the structure and function of savannas through shifts in moisture availability and increases in atmospheric carbon dioxide, in turn altering fire regimes with further feedbacks to climate. We explore opportunities to reduce net greenhouse gas emissions from savanna ecosystems through changes in savanna fire management. PMID:25044767

  15. A new fossil cichlid from the Middle Miocene in the East African Rift Valley (Tugen Hills, Central Kenya: First record of a putative Ectodini

    Directory of Open Access Journals (Sweden)

    Melanie Altner

    2015-11-01

    Full Text Available Identification of fossil cichlids is difficult, because the currently used diagnostic morphological characters for living cichlids are mostly soft tissue based and such characters are hardly preserved in fossils. During our recent fieldwork in the Central Kenya Rift (E-Africa, we discovered several exceptionally well-preserved fossil cichlids, which can be assigned to different lineages among the African Pseudocrenilabrinae. Here we present one of those new specimens. Its most conspicuous character is a lateral line divided into three segments. This specimen was found in the lacustrine sediments of the Middle Miocene site Waril, Tugen Hills, Kenya. The site represents the deposits of an ancient freshwater lake ca. 9-10 million years ago. Previous work on fossil leaves from the same site allow for the reconstruction of open vegetation surrounding the lake and pronounced dry seasons. Among the main further characteristics of the new fossil cichlid is a lachrimal with six lateral line canals, big cycloid scales and a low number of dorsal fin spines (XIII. The latter two characters are traceable in several members of tribes within the Pseudocrenilabrinae. However, a lachrimal with six lateral line canals is exclusively found in certain tribes of the EAR (East African Radiation within the Pseudocrenilabrinae. Moreover, the unique lateral line pattern is solely present in two genera of the EAR tribe Ectodini. However, the fossil shows cycloid scales, while modern Ectodini have ctenoid scales. Taken all evidence together, this fossil may perhaps represent an ancient lineage related to the Ectodini. Up to date, there is no definite fossil record of the members of the EAR. Our fossil may represent the first reliable calibration point for this group, which would be consistent with the previously reconstructed diversification time of the H-lineage (EAR tribes, except Boulengerochromini, Bathybatini, Trematocarini and Lamprologini and the Lamprologini ca

  16. Mixed farming : scope and constraints in West African savanna

    NARCIS (Netherlands)

    Slingerland, M.

    2000-01-01

    Since colonial times the crop livestock integration concept has been a leading development model in francophone West Africa. So far, it has failed in certain aspects, such as cultivation of fodder crops, intensification of cereal production through animal traction, and sedentarisation of

  17. Farming Systems of the African Savanna: A Continent in Crisis ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Farmers in the parts of Africa where population growth is near, or has exceeded, the carrying capacity of the land at current technological levels face a serious crisis. This crisis is the result of the breakdown of traditional farming systems. The consequences are environmental deterioration on a massive scale, widespread ...

  18. Determinants of patchiness of woody vegetation in an African savanna

    NARCIS (Netherlands)

    Veldhuis, Michiel P.; Rozen-Rechels, David; le Roux, Elizabeth; Cromsigt, Joris P.G.M.; Berg, Matheus P.; Olff, Han

    2016-01-01

    How is woody vegetation patchiness affected by rainfall, fire and large herbivore biomass? Can we predict woody patchiness and cover over large-scale environmental gradients? We quantified variation in local patchiness as the lacunarity of woody cover on satellite-derived images. Using Random Forest

  19. Characteristics of African Savanna Biomes for Determining Woody Cover

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set includes the soil and vegetation characteristics, herbivore estimates, and precipitation measurement data for the 854 sites described and analyzed in...

  20. Characteristics of African Savanna Biomes for Determining Woody Cover

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: This data set includes the soil and vegetation characteristics, herbivore estimates, and precipitation measurement data for the 854 sites described and...

  1. The reproductive lifespan of Onchocerca volvulus in West African savanna

    NARCIS (Netherlands)

    A.P. Plaisier (Anton); G.J. van Oortmarssen (Gerrit); J.H.F. Remme (Jan); J.D.F. Habbema (Dik)

    1991-01-01

    markdownabstractAbstract The epidemiological model ONCHOSIM — a model and computer simulation program for the transmission and control of onchocerciasis — has been used to determine the range of plausible values for the reproductive lifespan of Onchocerca volvulus. Model predictions based on

  2. Fire-free land use in pre-1492 Amazonian savannas.

    Science.gov (United States)

    Iriarte, José; Power, Mitchell J; Rostain, Stéphen; Mayle, Francis E; Jones, Huw; Watling, Jennifer; Whitney, Bronwen S; McKey, Doyle B

    2012-04-24

    The nature and scale of pre-Columbian land use and the consequences of the 1492 "Columbian Encounter" (CE) on Amazonia are among the more debated topics in New World archaeology and paleoecology. However, pre-Columbian human impact in Amazonian savannas remains poorly understood. Most paleoecological studies have been conducted in neotropical forest contexts. Of studies done in Amazonian savannas, none has the temporal resolution needed to detect changes induced by either climate or humans before and after A.D. 1492, and only a few closely integrate paleoecological and archaeological data. We report a high-resolution 2,150-y paleoecological record from a French Guianan coastal savanna that forces reconsideration of how pre-Columbian savanna peoples practiced raised-field agriculture and how the CE impacted these societies and environments. Our combined pollen, phytolith, and charcoal analyses reveal unexpectedly low levels of biomass burning associated with pre-A.D. 1492 savanna raised-field agriculture and a sharp increase in fires following the arrival of Europeans. We show that pre-Columbian raised-field farmers limited burning to improve agricultural production, contrasting with extensive use of fire in pre-Columbian tropical forest and Central American savanna environments, as well as in present-day savannas. The charcoal record indicates that extensive fires in the seasonally flooded savannas of French Guiana are a post-Columbian phenomenon, postdating the collapse of indigenous populations. The discovery that pre-Columbian farmers practiced fire-free savanna management calls into question the widely held assumption that pre-Columbian Amazonian farmers pervasively used fire to manage and alter ecosystems and offers fresh perspectives on an emerging alternative approach to savanna land use and conservation that can help reduce carbon emissions.

  3. Modeling soil moisture memory in savanna ecosystems

    Science.gov (United States)

    Gou, S.; Miller, G. R.

    2011-12-01

    Antecedent soil conditions create an ecosystem's "memory" of past rainfall events. Such soil moisture memory effects may be observed over a range of timescales, from daily to yearly, and lead to feedbacks between hydrological and ecosystem processes. In this study, we modeled the soil moisture memory effect on savanna ecosystems in California, Arizona, and Africa, using a system dynamics model created to simulate the ecohydrological processes at the plot-scale. The model was carefully calibrated using soil moisture and evapotranspiration data collected at three study sites. The model was then used to simulate scenarios with various initial soil moisture conditions and antecedent precipitation regimes, in order to study the soil moisture memory effects on the evapotranspiration of understory and overstory species. Based on the model results, soil texture and antecedent precipitation regime impact the redistribution of water within soil layers, potentially causing deeper soil layers to influence the ecosystem for a longer time. Of all the study areas modeled, soil moisture memory of California savanna ecosystem site is replenished and dries out most rapidly. Thus soil moisture memory could not maintain the high rate evapotranspiration for more than a few days without incoming rainfall event. On the contrary, soil moisture memory of Arizona savanna ecosystem site lasts the longest time. The plants with different root depths respond to different memory effects; shallow-rooted species mainly respond to the soil moisture memory in the shallow soil. The growing season of grass is largely depended on the soil moisture memory of the top 25cm soil layer. Grass transpiration is sensitive to the antecedent precipitation events within daily to weekly timescale. Deep-rooted plants have different responses since these species can access to the deeper soil moisture memory with longer time duration Soil moisture memory does not have obvious impacts on the phenology of woody plants

  4. Is the Okavango Delta the terminus of the East African Rift System? Towards a new geodynamic model: Geodetic study and geophysical review

    Science.gov (United States)

    Pastier, Anne-Morwenn; Dauteuil, Olivier; Murray-Hudson, Michael; Moreau, Frédérique; Walpersdorf, Andrea; Makati, Kaelo

    2017-08-01

    The Okavango Graben (OG) has been considered as the terminus of the southwestern branch of the East African Rift System (EARS) since the 1970s based on fault morphology and early seismic and geophysical data. Thus it has been assumed to be an incipient rifting zone, analogous to the early stage of mature rifts in the EARS. Recent geodetic data and geophysical studies in the area bring new insights into the local crust and lithosphere, mantle activity and fault activity. In this study, we computed the velocities for three permanent GPS stations surrounding the graben and undertook a review of the new geophysical data available for the area. The northern and southern blocks of the graben show an exclusively low strike-slip displacement rate of about 1mm/year, revealing the transtensional nature of this basin. The seismic record of central and southern Africa was found to be instrumentally biased for the events recorded before 2004 and the OG may not represent the most seismically active area in Botswana anymore. Moreover, no significant lithosphere and crustal thinning is found in the tectonic structure nor any strong negative Bouguer anomaly and surface heat flux. Thus the OG does not match the classical model for a rifting zone. We propose a new geodynamic model for the deformation observed west of the EARS based on accommodation of far-field deformation due to the differential extension rates of the EARS and the displacement of the Kalahari craton relative to the Nubian plate.

  5. Fatty acid composition of minced meat, longissimus muscle and omental fat from Small East African goats finished on different levels of concentrate supplementation.

    Science.gov (United States)

    Mushi, D E; Thomassen, M S; Kifaro, G C; Eik, L O

    2010-10-01

    Effects of supplementing Small East African (SEA) goats with concentrate diets on fatty acids composition of minced meat, M. longissimus dorsi (LD) and omental fat were assessed using 23 animals (14.5 months old and 20.1 kg body weight). Goats were subjected to four levels of concentrate supplementation: ad libitum concentrate allowance (T100), 66% (T66), 33% (T33) and 0% (T0) of ad libitum concentrate allowance. All goats were slaughtered after 90 days of experimental period. Minced meat from concentrate-supplemented goats had higher (Pmeat from T00 and T66 goats had similar proportions of polyunsaturated fatty acids (PUFA) and n-6 PUFA that were higher (Pgoats whereas margaric and arachidonic acids were in higher (Pgoats. Overall, LD was associated with PUFA, omental fat with saturated fatty acids (SFA), minced meat with MUFA. It is concluded that finishing SEA goats on concentrate diets will increase the proportion of DFA in meat from them. In addition, the proportion of PUFA in meat from such goats will peak at concentrate supplementation equivalent to 66% of their ad libitum intake. Consumers should avoid high intake of internal fat due to their richness in SFA. Copyright (c) 2010 The American Meat Science Association. Published by Elsevier Ltd. All rights reserved.

  6. Innovative solutions for intractable water problems in the face of climate change in southern and East African sub regions

    Science.gov (United States)

    Mapani, Benjamin; Makurira, Hodson; Magole, Lapologang; Meck, Maideyi; Mkandawire, Theresa; Mul, Marloes; Ngongondo, Cosmo

    2018-06-01

    This issue has a total of thirty-two (32) papers; and covers the IWRM sub themes of Hydrology, Land and People, Water Resources Management, Water and Environment and Wastewater and Sanitation. Water issues have become more and more complex as the supply side is affected by issues of quantity, availability and vulnerability due to natural factors such as climate change and urbanization. These challenges call for new management strategies and governance styles. Access to clean freshwater is a basic requirement for enhanced quality of life and development by all. However, this access has three main components that must be met adequately as this issue illustrates. These components are firstly, the quantity of water available; secondly, the quality and thirdly supply and appropriate delivery of this precious resource to domestic, commercial and industrial users. The demand side has also become more challenging, especially in urban areas as more and more people move from the rural areas to the cities. It has become a daily challenge in many African cities to supply water to these new urban dwellers and more so in unplanned settlements. These issues require a way and manner of delivering solutions and new innovative ideas. The topics in this issue vary from climate variability and how we are to improve our management strategies to mitigation, through to vulnerability of water resources and how to strengthen governance issues that plague some institutions in our region.

  7. The Integrated Genomic Architecture and Evolution of Dental Divergence in East African Cichlid Fishes (Haplochromis chilotes x H. nyererei

    Directory of Open Access Journals (Sweden)

    C. Darrin Hulsey

    2017-09-01

    Full Text Available The independent evolution of the two toothed jaws of cichlid fishes is thought to have promoted their unparalleled ecological divergence and species richness. However, dental divergence in cichlids could exhibit substantial genetic covariance and this could dictate how traits like tooth numbers evolve in different African Lakes and on their two jaws. To test this hypothesis, we used a hybrid mapping cross of two trophically divergent Lake Victoria species (Haplochromis chilotes × Haplochromis nyererei to examine genomic regions associated with cichlid tooth diversity. Surprisingly, a similar genomic region was found to be associated with oral jaw tooth numbers in cichlids from both Lake Malawi and Lake Victoria. Likewise, this same genomic location was associated with variation in pharyngeal jaw tooth numbers. Similar relationships between tooth numbers on the two jaws in both our Victoria hybrid population and across the phylogenetic diversity of Malawi cichlids additionally suggests that tooth numbers on the two jaws of haplochromine cichlids might generally coevolve owing to shared genetic underpinnings. Integrated, rather than independent, genomic architectures could be key to the incomparable evolutionary divergence and convergence in cichlid tooth numbers.

  8. Fertility Intentions, Pregnancy, and Use of PrEP and ART for Safer Conception Among East African HIV Serodiscordant Couples.

    Science.gov (United States)

    Heffron, Renee; Thomson, Kerry; Celum, Connie; Haberer, Jessica; Ngure, Kenneth; Mugo, Nelly; Bukusi, Elizabeth; Katabira, Elly; Odoyo, Josephine; Bulya, Nulu; Asiimwe, Stephen; Tindimwebwa, Edna; Baeten, Jared M

    2017-09-11

    African HIV serodiscordant couples often desire pregnancy, despite sexual HIV transmission risk during pregnancy attempts. Pre-exposure prophylaxis (PrEP) and antiretroviral therapy (ART) reduce HIV risk and can be leveraged for safer conception but how well these strategies are used for safer conception is not known. We conducted an open-label demonstration project of the integrated delivery of PrEP and ART among 1013 HIV serodiscordant couples from Kenya and Uganda followed quarterly for 2 years. We evaluated fertility intentions, pregnancy incidence, the use of PrEP and ART during peri-conception, and peri-conception HIV incidence. At enrollment, 80% of couples indicated a desire for more children. Pregnancy incidence rates were 18.5 and 18.7 per 100 person years among HIV-uninfected and HIV-infected women, and higher among women who recently reported fertility intention (adjusted odds ratio 3.43, 95% CI 2.38-4.93) in multivariable GEE models. During the 6 months preceding pregnancy, 82.9% of couples used PrEP or ART and there were no HIV seroconversions. In this cohort with high pregnancy rates, integrated PrEP and ART was readily used by HIV serodiscordant couples, including during peri-conception periods. Widespread scale-up of safer conception counseling and services is warranted to respond to strong desires for pregnancy among HIV-affected men and women.

  9. Poaching and human encroachment reverse recovery of African savannah elephants in south-east Angola despite 14 years of peace

    Science.gov (United States)

    Chase, Michael J.; Griffin, Curtice R.

    2018-01-01

    With populations of African savannah elephants (Loxodonta africana) declining across the continent, assessing the status of individual elephant populations is important for conservation. Angola’s elephant population represents a key linkage between the larger populations of Namibia and Botswana. Elephants in Angola were decimated during the 1975–2002 Angolan civil war, but a 2005 survey showed that populations were recolonizing former habitats. Between 2005 and 2015, no research was permitted on elephants in Angola, but elsewhere in Africa many elephant populations experienced a poaching crisis. In 2015, we were able to resume elephant research in Angola. We used aerial surveys and satellite monitoring of collared elephants to determine the current status of elephant populations in Angola and to learn how human populations may be affecting elephant habitat usage. The aerial survey revealed a population of 3,395 ± SE of 797 elephants, but populations had declined 21% from the 2005 estimate. The high number of carcasses observed on the survey suggests that populations may have increased after the 2005 survey but were declining rapidly as of 2015. Satellite-collared elephants avoided areas elephants from preferred habitats near rivers. Taken together, these results suggest that Angola’s elephant population is experiencing intense poaching and may be losing habitat to human settlements. Without action to conserve their populations, Angola’s elephants face an uncertain future. PMID:29538387

  10. Comparison of the reorganisations of BP and Shell and possible opportunities for Middle East and North African Oil companies

    Energy Technology Data Exchange (ETDEWEB)

    Jenkins, Gilbert

    1999-07-01

    A critical analysis is provided of the recent reorganisations of the downstream and petrochemical activities of BP and Shell. BP (or BP Amoco including Arco) and Shell are preparing for the next decade anticipating the environment and changing the companies to maximise their profitability in that environment. For the oil producing countries of the Middle East and North Africa (MENA), there are lessons to be learned both from the forecasts which BP Amoco and Shell are making and from the way these companies intend to operate. BP Amoco's view of oil refining is that the surplus capacity is endemic; Shell's view is that it is transient. BP Amoco will market oil products selectively across the world; Shell is still intent on a global approach. Both BP Amoco and Shell will minimise their wholesaling activities in the retail market and expand their merchandising with ever better quality sites. In the petrochemicals sector, the companies are taking similar actions, ie concentrating on positions of strength and selling business activities with low market shares or poor profitability. Petrochemical sites will be favoured when they have access to company produced hydrocarbon feedstocks. From the analysis, it is suggested that MENA oil companies will need to consider carefully the timing of any new refinery building. The reorganisation of the major OECD-based oil companies should offer opportunities for MENA companies to secure outlets for LPG and condensates, to form marketing alliances in OECD markets and to become involved in OECD-based petrochemical businesses.

  11. Comparison of the reorganisations of BP and Shell and possible opportunities for Middle East and North African Oil companies

    International Nuclear Information System (INIS)

    Jenkins, Gilbert

    1999-01-01

    A critical analysis is provided of the recent reorganisations of the downstream and petrochemical activities of BP and Shell. BP (or BP Amoco including Arco) and Shell are preparing for the next decade anticipating the environment and changing the companies to maximise their profitability in that environment. For the oil producing countries of the Middle East and North Africa (MENA), there are lessons to be learned both from the forecasts which BP Amoco and Shell are making and from the way these companies intend to operate. BP Amoco's view of oil refining is that the surplus capacity is endemic; Shell's view is that it is transient. BP Amoco will market oil products selectively across the world; Shell is still intent on a global approach. Both BP Amoco and Shell will minimise their wholesaling activities in the retail market and expand their merchandising with ever better quality sites. In the petrochemicals sector, the companies are taking similar actions, ie concentrating on positions of strength and selling business activities with low market shares or poor profitability. Petrochemical sites will be favoured when they have access to company produced hydrocarbon feedstocks. From the analysis, it is suggested that MENA oil companies will need to consider carefully the timing of any new refinery building. The reorganisation of the major OECD-based oil companies should offer opportunities for MENA companies to secure outlets for LPG and condensates, to form marketing alliances in OECD markets and to become involved in OECD-based petrochemical businesses

  12. Geomorphic Response to Spatial and Temporal Tectonic uplift on the Kenya Rift of East African Rift System

    Science.gov (United States)

    Xue, L.; Abdelsalam, M. G.

    2017-12-01

    Tectonic uplifts of the shoulders of the East Africa Rift System (EARS) have significant impact on the geological record by reorganizing drainage systems, increasing sediment supply, and changing climate and biogeography. Recent studies in geochronology, geomorphology and geophysics have provided some understanding of the timing of tectonic uplift and its distribution pattern of the (EARS). We do not know how the vertical motion is localized along the rift axis and the relative roles of upwelling of magma and rift extensional processes play in tectonic uplift history. This work presents detailed morphometric study of the fluvial landscape response to the tectonic uplift and climate shifting of the Kenya Rift shoulders in order to reconstruct their incision history, with special attention to timing, location, and intensity of uplift episodes. This work compiles the Shuttle Radar Topography Mission (SRTM) Digital Elevation Model (DEM) and Sentinel-2A data, summarized previous 39Ar-40Ar and thermochronology data, and calculates long-term incision rate and geomorphic proxies (normalized steepness and chi-integral) along the Kenya Rift. It also models the age of tectonic/climatic events by using knickpoint celerity model and R/SR integrative approach. It found that the maximum long-term incision rates of 300 mm/kyr to be at the central Kenya Rift, possibly related to the mantle-driven process and rapid tectonic uplift. The geomorphic proxies indicate southward decreasing pattern of the short-term incision rate, possibly related to the migration of the mantle plume.

  13. Institutional capacity for health systems research in East and Central African schools of public health: knowledge translation and effective communication.

    Science.gov (United States)

    Ayah, Richard; Jessani, Nasreen; Mafuta, Eric M

    2014-06-02

    Local health systems research (HSR) provides policymakers and practitioners with contextual, evidence-based solutions to health problems. However, producers and users of HSR rarely understand the complexities of the context within which each operates, leading to the "know-do" gap. Universities are well placed to conduct knowledge translation (KT) integrating research production with uptake. The HEALTH Alliance Africa Hub, a consortium of seven schools of public health (SPHs) in East and Central Africa, was formed to build capacity in HSR. This paper presents information on the capacity of the various SPHs to conduct KT activities. In 2011, each member of the Africa Hub undertook an institutional HSR capacity assessment using a context-adapted and modified self-assessment tool. KT capacity was measured by several indicators including the presence of a KT strategy, an organizational structure to support KT activities, KT skills, and institutional links with stakeholders and media. Respondents rated their opinions on the various indicators using a 5-point Likert scale. Averages across all respondents for each school were calculated. Thereafter, each school held a results validation workshop. A total of 123 respondents from all seven SPHs participated. Only one school had a clear KT strategy; more commonly, research was disseminated at scientific conferences and workshops. While most respondents perceived their SPH as having strong institutional ties with organizations interested in HSR as well as strong institutional leadership, the organizational structures required to support KT activities were absent. Furthermore, individual researchers indicated that they had little time or skills to conduct KT. Additionally, institutional and individual links with policymakers and media were reported as weak. Few SPHs in Africa have a clear KT strategy. Strengthening the weak KT capacity of the SPHs requires working with institutional leadership to develop KT strategies designed

  14. Estimating seroprevalence of herpes simplex virus type 1 among different Middle East and North African male populations residing in Qatar

    Science.gov (United States)

    Nasrallah, Gheyath K.; Dargham, Soha R.; Mohammed, Layla I.

    2017-01-01

    HSV‐1 epidemiology in the Middle East and North Africa (MENA) remains poorly understood. Our study aimed to measure HSV‐1 antibody prevalence (seroprevalence) and its age‐distribution among select MENA populations residing in Qatar. Sera were collected from male blood donors attending Hamad Medical Corporation 2013‐2015. A total of 2,077 sera were tested for anti‐HSV‐1 antibodies using HerpeSelect® 1 ELISA IgG kits (Focus Diagnostics, Cypress, CA). Robust Poisson regression was conducted to estimate adjusted infection prevalence ratios. Country‐specific HSV‐1 seroprevalence was estimated for 10 national populations: 97.5% among Egyptians, 92.6% among Yemenis, 90.7% among Sudanese, 88.5% among Syrians, 86.5% among Jordanians, 82.3% among Qataris, 81.4% among Iranians, 81.4% among Lebanese, 80.5% among Palestinians, and 77.0% among Pakistanis. Age‐specific HSV‐1 seroprevalence was estimated for Egypt, the Fertile Crescent (Iraq, Jordan, Lebanon, Palestine, and Syria), and Qatar. Seroprevalence increased with age among Fertile Crescent and Qatari nationals. Seroprevalence increased from 70.0% among those aged ≤ 24 years up to 98.0% among those aged ≥55 years among Fertile Crescent nationals. Seroprevalence was consistently above 90% for all ages among Egyptians. HSV‐1 seroprevalence is high in MENA, though with some variation across countries. The seroprevalence appears to have declined among current young age cohorts compared to its levels a few decades ago. PMID:28817197

  15. Continuous 1.3-million-year record of East African hydroclimate, and implications for patterns of evolution and biodiversity.

    Science.gov (United States)

    Lyons, Robert P; Scholz, Christopher A; Cohen, Andrew S; King, John W; Brown, Erik T; Ivory, Sarah J; Johnson, Thomas C; Deino, Alan L; Reinthal, Peter N; McGlue, Michael M; Blome, Margaret W

    2015-12-22

    The transport of moisture in the tropics is a critical process for the global energy budget and on geologic timescales, has markedly influenced continental landscapes, migratory pathways, and biological evolution. Here we present a continuous, first-of-its-kind 1.3-My record of continental hydroclimate and lake-level variability derived from drill core data from Lake Malawi, East Africa (9-15° S). Over the Quaternary, we observe dramatic shifts in effective moisture, resulting in large-scale changes in one of the world's largest lakes and most diverse freshwater ecosystems. Results show evidence for 24 lake level drops of more than 200 m during the Late Quaternary, including 15 lowstands when water levels were more than 400 m lower than modern. A dramatic shift is observed at the Mid-Pleistocene Transition (MPT), consistent with far-field climate forcing, which separates vastly different hydroclimate regimes before and after ∼800,000 years ago. Before 800 ka, lake levels were lower, indicating a climate drier than today, and water levels changed frequently. Following the MPT high-amplitude lake level variations dominate the record. From 800 to 100 ka, a deep, often overfilled lake occupied the basin, indicating a wetter climate, but these highstands were interrupted by prolonged intervals of extreme drought. Periods of high lake level are observed during times of high eccentricity. The extreme hydroclimate variability exerted a profound influence on the Lake Malawi endemic cichlid fish species flock; the geographically extensive habitat reconfiguration provided novel ecological opportunities, enabling new populations to differentiate rapidly to distinct species.

  16. Institutional capacity for health systems research in East and Central African Schools of Public Health: strengthening human and financial resources

    Science.gov (United States)

    2014-01-01

    Background Despite its importance in providing evidence for health-related policy and decision-making, an insufficient amount of health systems research (HSR) is conducted in low-income countries (LICs). Schools of public health (SPHs) are key stakeholders in HSR. This paper, one in a series of four, examines human and financial resources capacities, policies and organizational support for HSR in seven Africa Hub SPHs in East and Central Africa. Methods Capacity assessment done included document analysis to establish staff numbers, qualifications and publications; self-assessment using a tool developed to capture individual perceptions on the capacity for HSR and institutional dialogues. Key informant interviews (KIIs) were held with Deans from each SPH and Ministry of Health and non-governmental officials, focusing on perceptions on capacity of SPHs to engage in HSR, access to funding, and organizational support for HSR. Results A total of 123 people participated in the self-assessment and 73 KIIs were conducted. Except for the National University of Rwanda and the University of Nairobi SPH, most respondents expressed confidence in the adequacy of staffing levels and HSR-related skills at their SPH. However, most of the researchers operate at individual level with low outputs. The average number of HSR-related publications was only capacity. This study underscores the need to form effective multidisciplinary teams to enhance research of immediate and local relevance. Capacity strengthening in the SPH needs to focus on knowledge translation and communication of findings to relevant audiences. Advocacy is needed to influence respective governments to allocate adequate funding for HSR to avoid donor dependency that distorts local research agenda. PMID:24888371

  17. Two extended haplotype blocks are associated with adaptation to high altitude habitats in East African honey bees.

    Directory of Open Access Journals (Sweden)

    Andreas Wallberg

    2017-05-01

    Full Text Available Understanding the genetic basis of adaption is a central task in biology. Populations of the honey bee Apis mellifera that inhabit the mountain forests of East Africa differ in behavior and morphology from those inhabiting the surrounding lowland savannahs, which likely reflects adaptation to these habitats. We performed whole genome sequencing on 39 samples of highland and lowland bees from two pairs of populations to determine their evolutionary affinities and identify the genetic basis of these putative adaptations. We find that in general, levels of genetic differentiation between highland and lowland populations are very low, consistent with them being a single panmictic population. However, we identify two loci on chromosomes 7 and 9, each several hundred kilobases in length, which exhibit near fixation for different haplotypes between highland and lowland populations. The highland haplotypes at these loci are extremely rare in samples from the rest of the world. Patterns of segregation of genetic variants suggest that recombination between haplotypes at each locus is suppressed, indicating that they comprise independent structural variants. The haplotype on chromosome 7 harbors nearly all octopamine receptor genes in the honey bee genome. These have a role in learning and foraging behavior in honey bees and are strong candidates for adaptation to highland habitats. Molecular analysis of a putative breakpoint indicates that it may disrupt the coding sequence of one of these genes. Divergence between the highland and lowland haplotypes at both loci is extremely high suggesting that they are ancient balanced polymorphisms that greatly predate divergence between the extant honey bee subspecies.

  18. Using High-Resolution Data to Assess Land Use Impact on Nitrate Dynamics in East African Tropical Montane Catchments

    Science.gov (United States)

    Jacobs, Suzanne R.; Weeser, Björn; Guzha, Alphonce C.; Rufino, Mariana C.; Butterbach-Bahl, Klaus; Windhorst, David; Breuer, Lutz

    2018-03-01

    Land use change alters nitrate (NO3-N) dynamics in stream water by changing nitrogen cycling, nutrient inputs, uptake and hydrological flow paths. There is little empirical evidence of these processes for East Africa. We collected a unique 2 year high-resolution data set to assess the effects of land use (i.e., natural forest, smallholder agriculture and commercial tea plantations) on NO3-N dynamics in three subcatchments within a headwater catchment in the Mau Forest Complex, Kenya's largest tropical montane forest. The natural forest subcatchment had the lowest NO3-N concentrations (0.44 ± 0.043 mg N L-1) with no seasonal variation. NO3-N concentrations in the smallholder agriculture (1.09 ± 0.11 mg N L-1) and tea plantation (2.13 ± 0.19 mg N L-1) subcatchments closely followed discharge patterns, indicating mobilization of NO3-N during the rainy seasons. Hysteresis patterns of rainfall events indicate a shift from subsurface flow in the natural forest to surface runoff in agricultural subcatchments. Distinct peaks in NO3-N concentrations were observed during rainfall events after a longer dry period in the forest and tea subcatchments. The high-resolution data set enabled us to identify differences in NO3-N transport of catchments under different land use, such as enhanced NO3-N inputs to the stream during the rainy season and higher annual export in agricultural subcatchments (4.9 ± 0.3 to 12.0 ± 0.8 kg N ha-1 yr-1) than in natural forest (2.6 ± 0.2 kg N ha-1 yr-1). This emphasizes the usefulness of our monitoring approach to improve the understanding of land use effects on riverine N exports in tropical landscapes, but also the need to apply such methods in other regions.

  19. Two extended haplotype blocks are associated with adaptation to high altitude habitats in East African honey bees

    Science.gov (United States)

    Schöning, Caspar

    2017-01-01

    Understanding the genetic basis of adaption is a central task in biology. Populations of the honey bee Apis mellifera that inhabit the mountain forests of East Africa differ in behavior and morphology from those inhabiting the surrounding lowland savannahs, which likely reflects adaptation to these habitats. We performed whole genome sequencing on 39 samples of highland and lowland bees from two pairs of populations to determine their evolutionary affinities and identify the genetic basis of these putative adaptations. We find that in general, levels of genetic differentiation between highland and lowland populations are very low, consistent with them being a single panmictic population. However, we identify two loci on chromosomes 7 and 9, each several hundred kilobases in length, which exhibit near fixation for different haplotypes between highland and lowland populations. The highland haplotypes at these loci are extremely rare in samples from the rest of the world. Patterns of segregation of genetic variants suggest that recombination between haplotypes at each locus is suppressed, indicating that they comprise independent structural variants. The haplotype on chromosome 7 harbors nearly all octopamine receptor genes in the honey bee genome. These have a role in learning and foraging behavior in honey bees and are strong candidates for adaptation to highland habitats. Molecular analysis of a putative breakpoint indicates that it may disrupt the coding sequence of one of these genes. Divergence between the highland and lowland haplotypes at both loci is extremely high suggesting that they are ancient balanced polymorphisms that greatly predate divergence between the extant honey bee subspecies. PMID:28542163

  20. Challenges and opportunities in land surface modelling of savanna ecosystems

    Directory of Open Access Journals (Sweden)

    R. Whitley

    2017-10-01

    Full Text Available The savanna complex is a highly diverse global biome that occurs within the seasonally dry tropical to sub-tropical equatorial latitudes and are structurally and functionally distinct from grasslands and forests. Savannas are open-canopy environments that encompass a broad demographic continuum, often characterised by a changing dominance between C3-tree and C4-grass vegetation, where frequent environmental disturbances such as fire modulates the balance between ephemeral and perennial life forms. Climate change is projected to result in significant changes to the savanna floristic structure, with increases to woody biomass expected through CO2 fertilisation in mesic savannas and increased tree mortality expected through increased rainfall interannual variability in xeric savannas. The complex interaction between vegetation and climate that occurs in savannas has traditionally challenged terrestrial biosphere models (TBMs, which aim to simulate the interaction between the atmosphere and the land surface to predict responses of vegetation to changing in environmental forcing. In this review, we examine whether TBMs are able to adequately represent savanna fluxes and what implications potential deficiencies may have for climate change projection scenarios that rely on these models. We start by highlighting the defining characteristic traits and behaviours of savannas, how these differ across continents and how this information is (or is not represented in the structural framework of many TBMs. We highlight three dynamic processes that we believe directly affect the water use and productivity of the savanna system: phenology, root-water access and fire dynamics. Following this, we discuss how these processes are represented in many current-generation TBMs and whether they are suitable for simulating savanna fluxes.Finally, we give an overview of how eddy-covariance observations in combination with other data sources can be used in model

  1. "Getting tested is almost like going to the Salem witch trials": discordant discourses between Western public health messages and sociocultural expectations surrounding HIV testing among East African immigrant women.

    Science.gov (United States)

    De Jesus, Maria; Carrete, Claudia; Maine, Cathleen; Nalls, Patricia

    2015-01-01

    Washington, DC, has the highest AIDS diagnosis rate in the USA, and Black women are disproportionately affected. Although HIV testing is the first entryway into vital treatment services, evidence reveals that foreign-born blacks have a lower rate of recent HIV testing than US-born blacks. To date, however, there are no studies that examine the culture-specific perceptions of HIV testing among East African immigrant women (who comprise a large share of Black Africans in DC) to better understand their potential barriers to testing. Adopting the PEN-3 cultural model as our theoretical framework, the main objective of this study was to examine East African women's HIV testing perceptions and partner communication norms. Between October 2012 and March 2013, trained interviewers conducted a total of 25 interviews with East African women in the Washington, DC, metropolitan area. For triangulation purposes, data collection consisted of both in-depth, semi-structured interviews and cognitive interviews, in which participants were administered a quantitative survey and assessed on how they interpreted items. Qualitative thematic analysis revealed a systematic pattern of discordant responses across participants. While they were aware of messages related to Western public health discourse surrounding HIV testing (e.g., Everyone should get tested for HIV; One should talk to one's spouse about HIV testing), divergent sociocultural expectations rooted in cultural and religious beliefs prevailed (e.g., Getting an HIV test brings shame to the person who got tested and to one's family; it implies one is engaging in immoral behavior; One should not talk with one's spouse about HIV testing; doing so breaks cultural norms). Implications of using a culture-centered model to examine the role of sociocultural expectations in HIV prevention research and to develop culturally responsive prevention strategies are discussed.

  2. ‘Getting tested is almost like going to the Salem witch trials’: Discordant discourses between western public health messages and sociocultural expectations surrounding HIV testing among East African immigrant women

    Science.gov (United States)

    DE JESUS, Maria; CARRETE, Claudia; MAINE, Cathleen; NALLS, Patricia

    2015-01-01

    Washington, DC has the highest AIDS diagnosis rate in the United States and Black women are disproportionately affected. Although HIV testing is the first entryway into vital treatment services, evidence reveals that foreign-born blacks have a lower rate of recent HIV testing than U.S.-born blacks. To date, however, there are no studies that examine the culture-specific perceptions of HIV testing among East African immigrant women (who comprise a large share of Black Africans in DC) to better understand their potential barriers to testing. Adopting the PEN-3 cultural model as our theoretical framework, the main objective of this study was to examine East African women’s HIV testing perceptions and partner communication norms. Between October 2012 and March 2013, trained interviewers conducted a total of 25 interviews with East African women in the Washington DC Metropolitan area. For triangulation purposes, data collection consisted of both in-depth, semi-structured interviews and cognitive interviews, in which participants were administered a quantitative survey and assessed on how they interpreted items. Qualitative thematic analysis revealed a systematic pattern of discordant responses across participants. While they were aware of messages related to western public health discourse surrounding HIV testing (e.g., Everyone should get tested for HIV; One should talk to one’s spouse about HIV testing), divergent sociocultural expectations rooted in cultural and religious beliefs prevailed (e.g., Getting an HIV test brings shame to the person who got tested and to one’s family; it implies one is engaging in immoral behavior; One should not talk with one’s spouse about HIV testing; doing so breaks cultural norms). Implications of using a culture-centered model to examine the role of sociocultural expectations in HIV prevention research and to develop culturally responsive prevention strategies are discussed. PMID:25616443

  3. Fault kinematics and tectonic stress in the seismically active Manyara Dodoma Rift segment in Central Tanzania Implications for the East African Rift

    Science.gov (United States)

    Macheyeki, Athanas S.; Delvaux, Damien; De Batist, Marc; Mruma, Abdulkarim

    2008-07-01

    The Eastern Branch of the East African Rift System is well known in Ethiopia (Main Ethiopian Rift) and Kenya (Kenya or Gregory Rift) and is usually considered to fade away southwards in the North Tanzanian Divergence, where it splits into the Eyasi, Manyara and Pangani segments. Further towards the south, rift structures are more weakly expressed and this area has not attracted much attention since the mapping and exploratory works of the 1950s. In November 4, 2002, an earthquake of magnitude Mb = 5.5 struck Dodoma, the capital city of Tanzania. Analysis of modern digital relief, seismological and geological data reveals that ongoing tectonic deformation is presently affecting a broad N-S trending belt, extending southward from the North Tanzanian Divergence to the region of Dodoma, forming the proposed "Manyara-Dodoma Rift segment". North of Arusha-Ngorongoro line, the rift is confined to a narrow belt (Natron graben in Tanzania) and south of it, it broadens into a wide deformation zone which includes both the Eyasi and Manyara grabens. The two-stage rifting model proposed for Kenya and North Tanzania also applies to the Manyara-Dodoma Rift segment. In a first stage, large, well-expressed topographic and volcanogenic structures were initiated in the Natron, Eyasi and Manyara grabens during the Late Miocene to Pliocene. From the Middle Pleistocene onwards, deformations related to the second rifting stage propagated southwards to the Dodoma region. These young structures have still limited morphological expressions compared to the structures formed during the first stage. However, they appear to be tectonically active as shown by the high concentration of moderate earthquakes into earthquake swarms, the distribution of He-bearing thermal springs, the morphological freshness of the fault scarps, and the presence of open surface fractures. Fault kinematic and paleostress analysis of geological fault data in basement rocks along the active fault lines show that recent

  4. Evaporation from cultivated and semi-wild Sudanian Savanna in west Africa

    Science.gov (United States)

    Ceperley, Natalie C.; Mande, Theophile; van de Giesen, Nick; Tyler, Scott; Yacouba, Hamma; Parlange, Marc B.

    2017-08-01

    Rain-fed farming is the primary livelihood of semi-arid west Africa. Changes in land cover have the potential to affect precipitation, the critical resource for production. Turbulent flux measurements from two eddy-covariance towers and additional observations from a dense network of small, wireless meteorological stations combine to relate land cover (savanna forest and agriculture) to evaporation in a small (3.5 km2) catchment in Burkina Faso, west Africa. We observe larger sensible and latent heat fluxes over the savanna forest in the headwater area relative to the agricultural section of the watershed all year. Higher fluxes above the savanna forest are attributed to the greater number of exposed rocks and trees and the higher productivity of the forest compared to rain-fed, hand-farmed agricultural fields. Vegetation cover and soil moisture are found to be primary controls of the evaporative fraction. Satellite-derived vegetation index (NDVI) and soil moisture are determined to be good predictors of evaporative fraction, as indicators of the physical basis of evaporation. Our measurements provide an estimator that can be used to derive evaporative fraction when only NDVI is available. Such large-scale estimates of evaporative fraction from remotely sensed data are valuable where ground-based measurements are lacking, which is the case across the African continent and many other semi-arid areas. Evaporative fraction estimates can be combined, for example, with sensible heat from measurements of temperature variance, to provide an estimate of evaporation when only minimal meteorological measurements are available in remote regions of the world. These findings reinforce local cultural beliefs of the importance of forest fragments for climate regulation and may provide support to local decision makers and rural farmers in the maintenance of the forest areas.

  5. Beyond Precipitation: Physiographic Gradients Dictate the Relative Importance of Environmental Drivers on Savanna Vegetation

    Science.gov (United States)

    Campo-Bescós, Miguel A.; Muñoz-Carpena, Rafael; Kaplan, David A.; Southworth, Jane; Zhu, Likai; Waylen, Peter R.

    2013-01-01

    Background Understanding the drivers of large-scale vegetation change is critical to managing landscapes and key to predicting how projected climate and land use changes will affect regional vegetation patterns. This study aimed to improve our understanding of the role, magnitude and spatial distribution of the key environmental factors driving vegetation change in southern African savanna, and how they vary across physiographic gradients. Methodology/Principal Findings We applied Dynamic Factor Analysis (DFA), a multivariate times series dimension reduction technique to ten years of monthly remote sensing data (MODIS-derived normalized difference vegetation index, NDVI) and a suite of environmental covariates: precipitation, mean and maximum temperature, soil moisture, relative humidity, fire and potential evapotranspiration. Monthly NDVI was described by cyclic seasonal variation with distinct spatiotemporal patterns in different physiographic regions. Results support existing work emphasizing the importance of precipitation, soil moisture and fire on NDVI, but also reveal overlooked effects of temperature and evapotranspiration, particularly in regions with higher mean annual precipitation. Critically, spatial distributions of the weights of environmental covariates point to a transition in the importance of precipitation and soil moisture (strongest in grass-dominated regions with precipitation950 mm). Conclusions/Significance We quantified the combined spatiotemporal effects of an available suite of environmental drivers on NDVI across a large and diverse savanna region. The analysis supports known drivers of savanna vegetation but also uncovers important roles of temperature and evapotranspiration. Results highlight the utility of applying the DFA approach to remote sensing products for regional analyses of landscape change in the context of global environmental change. With the dramatic increase in global change research, this methodology augurs well for

  6. The African oil industry

    International Nuclear Information System (INIS)

    Ford, Mark; Griffiths, Thalia

    1999-10-01

    Contains Executive Summary and Chapters on: Adding value to African hydrocarbons in a global energy market; North Africa; East Africa; West Africa; Central Africa; Southern Africa; Strategies for Africa; Outlook. (Author)

  7. African Journals Online (AJOL)

    African Journals Online (AJOL)

    reviewed, African-published scholarly journals. Historically, scholarly information has flowed from North to South and from West to East. It has also been difficult ... Featured Country: Egypt, Arab Rep. Featured Journal: Alexandria Journal of Medicine ...

  8. Within-population isotopic niche variability in savanna mammals: disparity between carnivores and herbivores

    Directory of Open Access Journals (Sweden)

    Daryl eCodron

    2016-02-01

    Full Text Available Large mammal ecosystems have relatively simple food webs, usually comprising three – and sometimes only two – trophic links. Since many syntopic species from the same trophic level therefore share resources, dietary niche partitioning features prominently within these systems. In African and other subtropical savannas, stable carbon isotopes readily distinguish between herbivore species for which foliage and other parts of dicot plants (13C-depleted C3 vegetation are the primary resource (browsers and those for which grasses (13C-enriched C4 vegetation are staples (grazers. Similarly, carbon isotopes distinguish between carnivore diets that may be richer in either browser, grazer, or intermediate-feeding prey. Here, we investigate levels of carbon and nitrogen isotopic niche variation and niche partitioning within populations (or species of carnivores and herbivores from South African savannas. We emphasize predictable differences in within-population trends across trophic levels: we expect that herbivore populations, which require more foraging effort due to higher intake requirements, are far less likely to display within-population resource partitioning than carnivore populations. Our results reveal generally narrower isotopic niche breadths in herbivore than carnivore populations, but more importantly we find lower levels of isotopic differentiation across individuals within herbivore species. While these results offer some support for our general hypothesis, the current paucity of isotopic data for African carnivores limits our ability to test the complete set of predictions arising from our hypothesis. Nevertheless, given the different ecological and ecophysiological constraints to foraging behaviour within each trophic level, comparisons across carnivores and herbivores, which are possible within such simplified foodwebs, make these systems ideal for developing a process-based understanding of conditions underlying the evolution of

  9. Description of the savanna ecosystem project, Nylsvley, South Africa

    CSIR Research Space (South Africa)

    CSIR National Scientific Programmes Unit, CSIR

    1975-12-01

    Full Text Available practices. These savannas stretch in a broad belt across southern Africa and have been greatly affected by increasing exploitation during the past hundred years. Increases in useful productivity have been accompanied by such problems as bush encroachment...

  10. The biodiversity cost of carbon sequestration in tropical savanna

    OpenAIRE

    Abreu, Rodolfo C. R.; Hoffmann, William A.; Vasconcelos, Heraldo L.; Pilon, Natashi A.; Rossatto, Davi R.; Durigan, Giselda

    2017-01-01

    Tropical savannas have been increasingly viewed as an opportunity for carbon sequestration through fire suppression and afforestation, but insufficient attention has been given to the consequences for biodiversity. To evaluate the biodiversity costs of increasing carbon sequestration, we quantified changes in ecosystem carbon stocks and the associated changes in communities of plants and ants resulting from fire suppression in savannas of the Brazilian Cerrado, a global biodiversity hotspot. ...

  11. ISSN 2073 ISSN 2073-9990 East Cent. East Cent. East Cent. Afr. J.

    African Journals Online (AJOL)

    DELL

    East and Central African Journal of Surgery. ... collaboration in the writing and editing of Surgical Care at the District Hospital, ... increasing availability of computers and huge developments in software technology such ... Emergency Surgery ...

  12. Burned area detection based on Landsat time series in savannas of southern Burkina Faso

    Science.gov (United States)

    Liu, Jinxiu; Heiskanen, Janne; Maeda, Eduardo Eiji; Pellikka, Petri K. E.

    2018-02-01

    West African savannas are subject to regular fires, which have impacts on vegetation structure, biodiversity and carbon balance. An efficient and accurate mapping of burned area associated with seasonal fires can greatly benefit decision making in land management. Since coarse resolution burned area products cannot meet the accuracy needed for fire management and climate modelling at local scales, the medium resolution Landsat data is a promising alternative for local scale studies. In this study, we developed an algorithm for continuous monitoring of annual burned areas using Landsat time series. The algorithm is based on burned pixel detection using harmonic model fitting with Landsat time series and breakpoint identification in the time series data. This approach was tested in a savanna area in southern Burkina Faso using 281 images acquired between October 2000 and April 2016. An overall accuracy of 79.2% was obtained with balanced omission and commission errors. This represents a significant improvement in comparison with MODIS burned area product (67.6%), which had more omission errors than commission errors, indicating underestimation of the total burned area. By observing the spatial distribution of burned areas, we found that the Landsat based method misclassified cropland and cloud shadows as burned areas due to the similar spectral response, and MODIS burned area product omitted small and fragmented burned areas. The proposed algorithm is flexible and robust against decreased data availability caused by clouds and Landsat 7 missing lines, therefore having a high potential for being applied in other landscapes in future studies.

  13. Age-related tooth wear differs between forest and savanna primates.

    Directory of Open Access Journals (Sweden)

    Jordi Galbany

    Full Text Available Tooth wear in primates is caused by aging and ecological factors. However, comparative data that would allow us to delineate the contribution of each of these factors are lacking. Here, we contrast age-dependent molar tooth wear by scoring percent of dentine exposure (PDE in two wild African primate populations from Gabonese forest and Kenyan savanna habitats. We found that forest-dwelling mandrills exhibited significantly higher PDE with age than savanna yellow baboons. Mandrills mainly feed on large tough food items, such as hard-shell fruits, and inhabit an ecosystem with a high presence of mineral quartz. By contrast, baboons consume large amounts of exogenous grit that adheres to underground storage organs but the proportion of quartz in the soils where baboons live is low. Our results support the hypothesis that not only age but also physical food properties and soil composition, particularly quartz richness, are factors that significantly impact tooth wear. We further propose that the accelerated dental wear in mandrills resulting in flatter molars with old age may represent an adaptation to process hard food items present in their environment.

  14. Vulnerability of native savanna trees and exotic Khaya senegalensis to seasonal drought.

    Science.gov (United States)

    Arndt, Stefan K; Sanders, Gregor J; Bristow, Mila; Hutley, Lindsay B; Beringer, Jason; Livesley, Stephen J

    2015-07-01

    Seasonally dry ecosystems present a challenge to plants to maintain water relations. While native vegetation in seasonally dry ecosystems have evolved specific adaptations to the long dry season, there are risks to introduced exotic species. African mahogany, Khaya senegalensis Desr. (A. Juss.), is an exotic plantation species that has been introduced widely in Asia and northern Australia, but it is unknown if it has the physiological or phenotypic plasticity to cope with the strongly seasonal patterns of water availability in the tropical savanna climate of northern Australia. We investigated the gas exchange and water relations traits and adjustments to seasonal drought in K. senegalensis and native eucalypts (Eucalyptus tetrodonta F. Muell. and Corymbia latifolia F. Muell.) in a savanna ecosystem in northern Australia. The native eucalypts did not exhibit any signs of drought stress after 3 months of no rainfall and probably had access to deeper soil moisture late into the dry season. Leaf water potential, stomatal conductance, transpiration and photosynthesis all remained high in the dry season but osmotic adjustment was not observed. Overstorey leaf area index (LAI) was 0.6 in the native eucalypt savanna and did not change between wet and dry seasons. In contrast, the K. senegalensis plantation in the wet season was characterized by a high water potential, high stomatal conductance and transpiration and a high LAI of 2.4. In the dry season, K. senegalensis experienced mild drought stress with a predawn water potential -0.6 MPa. Overstorey LAI was halved, and stomatal conductance and transpiration drastically reduced, while minimum leaf water potentials did not change (-2 MPa) and no osmotic adjustment occurred. Khaya senegalensis exhibited an isohydric behaviour and also had a lower hydraulic vulnerability to cavitation in leaves, with a P50 of -2.3 MPa. The native eucalypts had twice the maximum leaf hydraulic conductance but a much higher P50 of -1.5 MPa

  15. African Journals Online (AJOL)

    African Journals Online (AJOL)

    Historically, scholarly information has flowed from North to South and from West to East. It has also been difficult for African researchers to access the work of other African academics. In partnership with hundreds of journals from all ... Featured Country: Nigeria, Featured Journal: Nigeria Journal of Business Administration ...

  16. Assessing diet in savanna herbivores using stable carbon isotope ratios of faeces

    Directory of Open Access Journals (Sweden)

    D. Codron

    2005-06-01

    Full Text Available In African savannas, browse-based resources (@3 plants are isotopically distinct from grasses (@4 plants. The carbon isotopic composition of the basic plant diet is recorded in animal tissues. Mammal faeces are a readily accessible, non-invasive, sample material for temporally resolved dietary reconstructions. Faeces, however, include both undigested plant matter and waste, hence accuracy of dietary calculations could potentially be compromised by shifts in plant isotopic values related to seasonal or spatial differences, or by variability in the isotopic differences between faeces and diet. A controlled feeding study of four ungulate species showed a small, consistent difference between diet and faeces of-0.9 o, irrespective of whether the diet was @3 or C4-based. Results from faeces oftaxa known to be pure grazers, pure browsers, and mixed-feeders from the Kruger National Park were entirely consistent with their diets, but the accuracy of dietary reconstructions is enhanced with data from local plant communities.

  17. Conformity of package inserts information to regulatory requirements among selected branded and generic medicinal products circulating on the East African market.

    Science.gov (United States)

    Sillo, Hiiti B; Masota, Nelson E; Kisoma, Sunday; Rago, Lembit; Mgoyela, Veronica; Kaale, Eliangiringa A

    2018-01-01

    Availability of correct and adequate information about medicines is an important aspect in ensuring rational use of medicines and hence facilitating safety and expected efficacy of medicines during therapy. Package inserts have proven to be a good source of information to the prescribers and patients whereby they have been useful in highlighting important information pertaining proper use and handling of the medicines. The present study was aimed at establishing the extent to which package inserts of medicines circulating on the markets of the East African Community (EAC) Partner States conform to medicines information requirements as established in the harmonized guidelines as well as national guidelines. A total of 99 package inserts from six (6) types of medicines namely Albendazole, Artemether/Lumefantrine (ALu), Ciprofloxacin, Paracetamol, Amoxicillin and Metronidazole were purposefully collected from three EAC Partner States: Kenya, Tanzania and Uganda. The medicines were selected based on their indications as first line treatments, high rates of utilization within the medicines supply system and their positions in treatment of diseases of public importance across EAC Partner States. The inserts were evaluated on the availability of information regarding fifteen (15) parameters as extracted from the EAC harmonized guidelines for registration of medicines. Moreover, comparisons were made between the percentage conformity of the branded versus generic products, markets from which the samples were collected, origin of the manufacturer and type of medicine. Majority (93.9-100%) of the medicines' package inserts highly conformed to the inclusion of the information regarding the description and composition of the medications, indications, dosage and methods of administration, warnings and precautions, contraindications and storage conditions. However, the information on handling and disposal, container package description, excipients used, clinical pharmacology of

  18. Modeling the Sedimentary Infill of Lakes in the East African Rift: A Case Study of Multiple versus Single Rift Basin Segments

    Science.gov (United States)

    Zhang, C.; Scholz, C. A.

    2016-12-01

    The sedimentary basins in the East African Rift are considered excellent modern examples for investigating sedimentary infilling and evolution of extensional systems. Some lakes in the western branch of the rift have formed within single-segment systems, and include Lake Albert and Lake Edward. The largest and oldest lakes developed within multi-segment systems, and these include Lake Tanganyika and Lake Malawi. This research aims to explore processes of erosion and sedimentary infilling of the catchment area in single-segment rift (SSR) and multi-segment rift (MSR) systems. We consider different conditions of regional precipitation and evaporation, and assess the resulting facies architecture through forward modeling, using state-of-the-art commercial basin modeling software. Dionisos is a three-dimensional numerical stratigraphic forward modeling software program, which simulates basin-scale sediment transport based on empirical water- and gravity-driven diffusion equations. It was classically used to quantify the sedimentary architecture and basin infilling of both marine siliciclastic and carbonate environments. However, we apply this approach to continental rift basin environments. In this research, two scenarios are developed, one for a MSR and the other for a SSR. The modeled systems simulate the ratio of drainage area and lake surface area observed in modern Lake Tanganyika and Lake Albert, which are examples of MSRs and SSRs, respectively. The main parameters, such as maximum subsidence rate, water- and gravity-driven diffusion coefficients, rainfall, and evaporation, are approximated using these real-world examples. The results of 5 million year model runs with 50,000 year time steps show that MSRs are characterized by a deep water lake with relatively modest sediment accumulation, while the SSRs are characterized by a nearly overfilled lake with shallow water depths and thick sediment accumulation. The preliminary modeling results conform to the features

  19. Geomorphometric reconstruction of post-eruptive surfaces of the Virunga Volcanic Province (East African Rift), constraint of erosion ratio and relative chronology

    Science.gov (United States)

    Lahitte, Pierre; Poppe, Sam; Kervyn, Matthieu

    2016-04-01

    Quaternary volcanic landforms result from a complex evolution, involving volcanic constructional events and destructive ones by collapses and long-term erosion. Quantification, by morphometric approaches, of the evolution through time of the volcano shape allows the estimation of relative ages between volcanoes sharing the same climate and eruptive conditions. We apply such method to six volcanoes of the Virunga Volcanic Province in the western branch of the East African Rift Valley that still has rare geochronological constraints. As they have comparable sizes, volcanic history and erupted products, these edifices may have undergone comparable conditions of erosion which justify the deduction of relative chronology from their erosion pattern. Our GIS-based geomorphometric approach, the SHAPEVOLC algorithm, quantifies erupted or dismantled volumes by numerically modeling topographies resulting from the eruptive construction of each volcano. Constraining points are selected by analyses of morphometric properties of each cell of the current DEM, as the loci where the altitude is still representative of the un-eroded volcanic surfaces. A primary elevation surface is firstly adjusted to these constraining points by modeling a first-order pseudo-radial surface defined by: 1. the curve best fitting the concave-upwards volcano profile; 2. the location and elevation of the volcano summit; and 3. the possible eccentricity and azimuth parameters that allow to stretch and contract contours to adjust the shape of the model to the elliptically-shaped surface of the volcano. A second-order surface is next computed by local adjustment of the first-order surface to the constraining points to obtain the definitive primary elevation surface of the considered volcanic construct. Amount of erosion is obtained by summing the difference in elevation between reconstructed surfaces and current ones that allows to establish relative ages of volcanoes. For the 6 studied Virunga volcanoes

  20. Spatio-temporal characteristics of the Equatorial Ionization Anomaly (EIA) in the East African region via ionospheric tomography during the year 2012

    Science.gov (United States)

    Kassa, T.; Damtie, B.; Bires, A.; Yizengaw, E.; Cilliers, P.

    2015-01-01

    We present the characteristics of the EIA in the East African sector inferred from ground-based GPS receivers via ionospheric tomography during the year 2012. For the analysis, we developed and used a 2D ionospheric tomography imaging software based on Bayesian inversion approach. To reconstruct ionospheric electron density form slant Total Electron Content (sTEC) measurements, we selected a chain of ten ground-based GPS receivers with stations' codes and geomagnetic coordinates: ARMI (3.03 °S, 109.29 °E), DEBK (4.32 °N, 109.48 °E), ASOS (1.14 °N, 106.16 °E), NEGE (3.60 °S, 111.35 °E), SHIS (3.26 °N, 110.62 °E), ASAB (4.91 °N, 114.34 °E), SHEB (7.36 °N, 110.60 °E), EBBE (9.54 °S, 104.10 °E), DODM (16.03 °S, 109.04 °E) & NAMA (11.49 °N, 113.60 °E). The temporal, spatial and storm-time characteristics of the EIA and the hourly, day-to-day and seasonal variations of the maximum electron density of F2 region (NmF2) at 15.29°S geomagnetic latitude are presented. We found that the magnitude of the peak and the width/thickness of the EIA pronounced during the equinox and weakened during the solstice seasons at 2100 LT. It is also observed that the EIA persisted for longer time in equinox season than the solstice season. The spatial appearance of the northern and southern anomalies are observed starting from 6.12 ° N and 10 ° S respectively along geomagnetic latitude during equinox season. The EIA is localized between 180 km and 450 km along the altitude during December solstice. The analysis on the NmF2 demonstrated a significant dependence on local time, day and season of the year. We also investigated the storm response of the EIA for the magnetic storm of Day Of the Year (DOY) 274-276. It is observed that the disturbance dynamo related composition change (O/N2 ratio) resulted in a well-developed EIA with an increase in the peak and the width of the EIA at 2100 LT on DOY 275 (main phase of the storm) compared to 274 (initial phase of the storm

  1. East African Journal of Sciences

    African Journals Online (AJOL)

    ... resources, education, natural sciences, human and animal health sciences. ... Grain Yield and Economic Benefit of Intercropping Barley and Faba Bean in the ... Growth of Botrytis fabae and Manage Chocolate Spot Severity on Faba Bean ...

  2. East African Medical Journal: Submissions

    African Journals Online (AJOL)

    Communications should be addressed to the Editor-in-Chief, P.O. Box 41632, ... and the identity of any individual concealed according to ethical requirements. ... not wish to publish materials that has appeared beforehand in public media.

  3. The development of savanna afforestation in northern Nigeria

    Energy Technology Data Exchange (ETDEWEB)

    Kadeba, O. (Forestry Research Institute, Ibadan (Nigeria))

    1978-06-01

    The savanna woodland which covers over 80% of the land area of Nigeria is not capable of meeting the requirements of its population for wood and wood products. Since its inception in 1964, the Savanna Forestry Research Project has been concerned mainly with the problems of wood production in this region. The major constraints to tree planting, which include seasonal deficiencies of soil and atmospheric moisture, low levels of soil fertility, selection of suitable exotic tree species and competition in the early stages of tree growth with grasses, have been identified. References are made to some of the major problems that have been solved and those that are being tackled. Some species of exotic trees have proven adaptive to the savanna conditions and are known to be superior to the native savanna trees in terms of growth rates, yields and utility values. The exotic trees which can grown well in the different savanna climatic zones include several species of Eucalyptus and Pinus in addition to teak (Tectona grandis), Gmelina arborea, and neem (Azadirachta indica).

  4. The biodiversity cost of carbon sequestration in tropical savanna.

    Science.gov (United States)

    Abreu, Rodolfo C R; Hoffmann, William A; Vasconcelos, Heraldo L; Pilon, Natashi A; Rossatto, Davi R; Durigan, Giselda

    2017-08-01

    Tropical savannas have been increasingly viewed as an opportunity for carbon sequestration through fire suppression and afforestation, but insufficient attention has been given to the consequences for biodiversity. To evaluate the biodiversity costs of increasing carbon sequestration, we quantified changes in ecosystem carbon stocks and the associated changes in communities of plants and ants resulting from fire suppression in savannas of the Brazilian Cerrado, a global biodiversity hotspot. Fire suppression resulted in increased carbon stocks of 1.2 Mg ha -1 year -1 since 1986 but was associated with acute species loss. In sites fully encroached by forest, plant species richness declined by 27%, and ant richness declined by 35%. Richness of savanna specialists, the species most at risk of local extinction due to forest encroachment, declined by 67% for plants and 86% for ants. This loss highlights the important role of fire in maintaining biodiversity in tropical savannas, a role that is not reflected in current policies of fire suppression throughout the Brazilian Cerrado. In tropical grasslands and savannas throughout the tropics, carbon mitigation programs that promote forest cover cannot be assumed to provide net benefits for conservation.

  5. Identification of four novel HLA-B alleles, B*1590, B*1591, B*2726, and B*4705, from an East African population by high-resolution sequence-based typing.

    Science.gov (United States)

    Luo, M; Mao, X; Plummer, F A

    2005-02-01

    We report here four novel HLA-B alleles, B*1590, B*1591, B*2726, and B*4705, identified from an East African population during sequence-based HLA-B typing. The novel alleles were confirmed by sequencing two separate polymerase chain reaction products, and by molecular cloning and sequencing multiple clones. B*1590 is identical to B*1510 at exon 2 and exon 3, except for a difference (GCCGTC) at codon 158. Sequence differences at codon 152 (GAGGTG) and codon 167 (TGGTCG) differentiate B*1591 from B*1503 at exon 3. B*2726 is identical to B*2708 at exon 2 and exon 3, except for a difference (AAGCAG) at codon 70. B*4705 was identified in three Kenyan women. The allele is identical to B*47010101/02 at exon 2 and exon 3, except for differences at codon 97 (AGGAAT) and codon 99 (TTTTAT). These new alleles have been named by the WHO Nomenclature Committee. Identification of these novel HLA-B alleles reflects the genetic diversity of this East African population.

  6. The Design and Evaluation of African Language Learning Materials. Proceedings of the Spring 1984 Conference on Developing Guidelines for the Evaluation of African Language Learning Materials (East Lansing, Michigan, April 13-14, 1984).

    Science.gov (United States)

    Dwyer, David J., Ed.

    Representatives from major institutions teaching African languages convened to discuss the design of African language textbooks and to propose guidelines for the writing of new textbooks and evaluation of existing ones. Conference papers include: "Language Acquisition Theory and Materials Construction" (Stephen Krashen); "The Structures of Verbal…

  7. Fungus-Growing Termites Originated in African Rain Forest

    DEFF Research Database (Denmark)

    Aanen, Duur Kornelis; Eggleton, Paul

    2005-01-01

    are consumed (cf. [ [1] and [2] ]). Fungus-growing termites are found throughout the Old World tropics, in rain forests and savannas, but are ecologically dominant in savannas [ 3 ]. Here, we reconstruct the ancestral habitat and geographical origin of fungus-growing termites. We used a statistical model...... of habitat switching [ 4 ] repeated over all phylogenetic trees sampled in a Bayesian analysis of molecular data [ 5 ]. Our reconstructions provide strong evidence that termite agriculture originated in African rain forest and that the main radiation leading to the extant genera occurred there. Because...

  8. Soil physical conditions in Nigerian savannas and biomass production

    International Nuclear Information System (INIS)

    Salako, F.K.

    2004-01-01

    Nigeria is located in the tropical zone, with a vast area having savanna vegetation. This is a region that is itself diverse, necessitating a classification into derived savanna, southern Guinea savanna and northern Guinea savanna. These classifications reflect environmental characteristics such as length of growing period, which for instance is 151-180 days for the northern Guinea savanna, 181-210 days for the southern Guinea savanna and 211-270 days for the derived savanna/coastal savanna. The major soils found in the various agro-ecological zones have coarse-textured surface soil, and are low in organic matter and chemical fertility. Although, yields can be improved by addition of inorganic and organic fertilizer, this can only be sustained and assured with high soil physical qualities. Soil physical qualities can be sustained at a high level with conservation tillage and soil conservation measures. Tillage is physical manipulation of the soil. Thus, the most profound effect of tillage is in relation to soil physical properties. For socio-economic and cultural reasons, manual tillage is still widely practiced in Africa as farming is largely at subsistence level. However, there are now a number of commercial farms especially for cash crop production in many parts of Africa. Many of these are located in locations which were hitherto reserved as forest and a need for sustainable production in pertinent to maintain ecological balance. Soils with coarse texture are not often sensitive to some physical parameters while some physical parameters are more relevant in a given study than others. Sustainable crop production researches in the tropics have focused on the role of planted fallows and their spatial arrangement (e.g., as in alley cropping) for many decades. Application of soil physics in the area of food production and environmental management still lags behind other sub-disciplines of soil science, particularly soil fertility in the tropics. A great challenge is

  9. On being African and Reformed? Towards an African Reformed ...

    African Journals Online (AJOL)

    2014-06-17

    Jun 17, 2014 ... It is furthermore our contention that the notion of culture and African worldviews was always perceived negatively ..... dean of the South East Asia Graduate School of Theology. He later .... Another Reformed church for Indian.

  10. The Influence of Cattle Wastes on Degraded Savanna Soils of ...

    African Journals Online (AJOL)

    This paper examines the effects of cattle wastes on degraded savanna soils of Kwara State, Nigeria. A total of 40 soil samples were systematically collected from five quadrats of 12m x 12m. In 4 identified cattle sheds and 1 in adjacent fallow land (control field) on the same soil, climatic type and ecological zone. Standard ...

  11. Restoring a disappearing ecosystem: the Longleaf Pine Savanna.

    Energy Technology Data Exchange (ETDEWEB)

    Harrington, Timothy B. [USFS; Miller, Karl V. [University of Georgia; Park, Noreen

    2013-05-01

    Longleaf pine (Pinus palustris) savannas of the southeastern United States contain some of the worlds most diverse plant communities, along with a unique complement of wildlife. Their traditionally open canopy structure and rich understory of grasses and herbs were critical to their vigor. However, a long history of land-use practices such as logging, farming, and fire exclusion have reduced this once-widespread ecosystem to only 3 percent of its original range. At six longleaf pine plantations in South Carolina, Tim Harrington with the Pacific Northwest Research Station and collaborators with the Southern Research Station used various treatments (including prescribed burns, tree thinning, and herbicide applications) to alter the forest structure and tracked how successful each one was in advancing savanna restoration over a 14-year period. They found that typical planting densities for wood production in plantations create dense understory shade that excludes many native herbaceous species important to savannas and associated wildlife. The scientists found that although tree thinning alone did not result in sustained gains, a combination of controlled burning, thinning, and herbicide treatments to reduce woody plants was an effective strategy for recovering the savanna ecosystem. The scientists also found that these efforts must be repeated periodically for enduring benefits.

  12. Nitrogen inputs by precipitation in the Nigerian Savanna | Adeniyi ...

    African Journals Online (AJOL)

    Inorganic nitrogen input via direct bulk precipitation was measured, and the relation between the different nitrogen species and rainfall characteristics determined over three rainy seasons at Shagunu, a remote, sparsely populated, non-industrialized site in the northern Guinea savanna of Nigeria. Nitrogen concentration per ...

  13. Termites of the Savanna ecosystem project study area, Nylsvley

    CSIR Research Space (South Africa)

    Ferrar, P

    1982-09-01

    Full Text Available This report describes the termite fauna of the Savanna Ecosystem Project study area at the Nylsvley Nature Reserve, with an illustrated key for identification of species. Twenty-one species of fifteen genera and two families are recorded, and notes...

  14. Erratum: Vascular epiphyte vegetation in rocky savannas of southeastern Brazil

    Czech Academy of Sciences Publication Activity Database

    Alves, R. J. V.; Kolbek, Jiří; Becker, J.

    2009-01-01

    Roč. 27, č. 4 (2009), s. 351-352 ISSN 0107-055X Institutional research plan: CEZ:AV0Z60050516 Keywords : epiphytes * Brazil * rocky savannas Subject RIV: EF - Botanics Impact factor: 0.868, year: 2009

  15. Invasive Andropogon gayanus (gamba grass) is an ecosystem transformer of nitrogen relations in Australian savanna.

    Science.gov (United States)

    Rossiter-Rachor, N A; Setterfield, S A; Douglas, M M; Hutley, L B; Cook, G D; Schmidt, S

    2009-09-01

    Invasion by the African grass Andropogon gayanus is drastically altering the understory structure of oligotrophic savannas in tropical Australia. We compared nitrogen (N) relations and phenology of A. gayanus and native grasses to examine the impact of invasion on N cycling and to determine possible reasons for invasiveness of A. gayanus. Andropogon gayanus produced up to 10 and four times more shoot phytomass and root biomass, with up to seven and 2.5 times greater shoot and root N pools than native grass understory. These pronounced differences in phytomass and N pools between A. gayanus and native grasses were associated with an altered N cycle. Most growth occurs in the wet season when, compared with native grasses, dominance of A. gayanus was associated with significantly lower total soil N pools, lower nitrification rates, up to three times lower soil nitrate availability, and up to three times higher soil ammonium availability. Uptake kinetics for different N sources were studied with excised roots of three grass species ex situ. Excised roots of A. gayanus had an over six times higher-uptake rate of ammonium than roots of native grasses, while native grass Eriachne triseta had a three times higher uptake rate of nitrate than A. gayanus. We hypothesize that A. gayanus stimulates ammonification but inhibits nitrification, as was shown to occur in its native range in Africa, and that this modification of the soil N cycle is linked to the species' preference for ammonium as an N source. This mechanism could result in altered soil N relations and could enhance the competitive superiority and persistence of A. gayanus in Australian savannas.

  16. Disentangling how landscape spatial and temporal heterogeneity affects Savanna birds.

    Directory of Open Access Journals (Sweden)

    Bronwyn Price

    Full Text Available In highly seasonal tropical environments, temporal changes in habitat and resources are a significant determinant of the spatial distribution of species. This study disentangles the effects of spatial and mid to long-term temporal heterogeneity in habitat on the diversity and abundance of savanna birds by testing four competing conceptual models of varying complexity. Focussing on sites in northeast Australia over a 20 year time period, we used ground cover and foliage projected cover surfaces derived from a time series of Landsat Thematic Mapper imagery, rainfall data and site-level vegetation surveys to derive measures of habitat structure at local (1-100 ha and landscape (100-1000s ha scales. We used generalised linear models and an information theoretic approach to test the independent effects of spatial and temporal influences on savanna bird diversity and the abundance of eight species with different life-history behaviours. Of four competing models defining influences on assemblages of savanna birds, the most parsimonious included temporal and spatial variability in vegetation cover and site-scale vegetation structure, suggesting savanna bird species respond to spatial and temporal habitat heterogeneity at both the broader landscape scale and at the fine-scale. The relative weight, strength and direction of the explanatory variables changed with each of the eight species, reflecting their different ecology and behavioural traits. This study demonstrates that variations in the spatial pattern of savanna vegetation over periods of 10 to 20 years at the local and landscape scale strongly affect bird diversity and abundance. Thus, it is essential to monitor and manage both spatial and temporal variability in avian habitat to achieve long-term biodiversity outcomes.

  17. Disentangling how landscape spatial and temporal heterogeneity affects Savanna birds.

    Science.gov (United States)

    Price, Bronwyn; McAlpine, Clive A; Kutt, Alex S; Ward, Doug; Phinn, Stuart R; Ludwig, John A

    2013-01-01

    In highly seasonal tropical environments, temporal changes in habitat and resources are a significant determinant of the spatial distribution of species. This study disentangles the effects of spatial and mid to long-term temporal heterogeneity in habitat on the diversity and abundance of savanna birds by testing four competing conceptual models of varying complexity. Focussing on sites in northeast Australia over a 20 year time period, we used ground cover and foliage projected cover surfaces derived from a time series of Landsat Thematic Mapper imagery, rainfall data and site-level vegetation surveys to derive measures of habitat structure at local (1-100 ha) and landscape (100-1000s ha) scales. We used generalised linear models and an information theoretic approach to test the independent effects of spatial and temporal influences on savanna bird diversity and the abundance of eight species with different life-history behaviours. Of four competing models defining influences on assemblages of savanna birds, the most parsimonious included temporal and spatial variability in vegetation cover and site-scale vegetation structure, suggesting savanna bird species respond to spatial and temporal habitat heterogeneity at both the broader landscape scale and at the fine-scale. The relative weight, strength and direction of the explanatory variables changed with each of the eight species, reflecting their different ecology and behavioural traits. This study demonstrates that variations in the spatial pattern of savanna vegetation over periods of 10 to 20 years at the local and landscape scale strongly affect bird diversity and abundance. Thus, it is essential to monitor and manage both spatial and temporal variability in avian habitat to achieve long-term biodiversity outcomes.

  18. Des-A-lupane in an East African lake sedimentary record as a new proxy for the stable carbon isotopic composition of C3 plants

    NARCIS (Netherlands)

    van Bree, Loes G.J.; Rijpstra, W. Irene C; Al-Dhabi, N.A.; Verschuren, D.; Sinninghe Damste, J.S.; de Leeuw, J.W.

    2016-01-01

    We studied the high-resolution and well-dated 25,000 year sedimentary record of Lake Challa, a deep tropical crater lake in equatorial East Africa, to explore new proxies for paleoenvironmental and paleohydrological change. Sedimentary biomarker analysis revealed the presence of des-A-triterpenoids

  19. Chemical and Physical Weathering of Granites in a Semi-Arid Savanna

    Science.gov (United States)

    Khomo, L.; Hartshorn, A.; Chadwick, O.; Kurtz, A.; Heimsath, A.; Rogers, K.

    2005-12-01

    The catena concept describes soil properties on hillslopes and implies a hydrological mass redistribution process that has been applied differently in different parts of the Earth. In tectonically active regions, it is mostly used to describe the redistribution of mass by overland flow leading to thickening soil mantles downslope. This application is somewhat different from its initial and still popular usage in tectonically inactive areas of Africa, where it defines long-term soil property differentiation along hillslopes as controlled by internal soil hydrology as opposed to overland flow. Many ecologists have found the "African" catena concept to be useful as an organizing principal for savanna studies, but there has been little recent research on catenas per se in Africa. Elsewhere however, there is a growing body of research that places the concept ever more strongly into a landscape evolution context. Here, we apply these new approaches to catenas in a South African savanna underlain by a heterogeneous suite of Basement granites straddling a gradient in effective precipitation. We constrain the weathering extent of hilly terrains formed on these oldrocks by calculating element losses with solid-phase mass-balance calculations augmented by cosmogenic (26Al/10Be) derived rates of landscape denudation. We test the efficacy of Ti, Zr and Nb as immobile elements to benchmark chemical losses and gains in these semi-arid weathering environments. We also trace and quantify the abundance of the host minerals for these elements (Ti = rutile and ilmenite, Nb = columbite and Zr = zircon and baddleyite) in a variety of rocks in the basement complex. This analysis provides the boundary conditions for assigning immobile elements to parent materials required for the mass balance calculations. We calculate total denudation using the cosmogenic isotopes and then partition it into chemical and physical loss vectors using the mass balance calculations for representative

  20. Collection of stand data for ordination | AJ | African Journal of Range ...

    African Journals Online (AJOL)

    African Journal of Range and Forage Science ... Four field stand tables for collecting data for the ordination of species and stands in Mopani Veld are described. The type of ... Keywords: surveys|trees|relative densities|relative frequency parameters|canopy spreads|bushveld|Savanna Biome|methods|data capture|Mopani ...

  1. Effects of vegetation burning on the atmospheric chemistry of the Venezuelan savanna

    International Nuclear Information System (INIS)

    Sanhueza, E.

    1991-01-01

    Biomass burning in tropical savanna and rainforest regions is an important factor in the chemical composition of the atmosphere. On the global scale, burning of savanna grass procedures three to four times greater emission of trace gases than deforestation processes of tropical rainforest. As part of a comprehensive study of the Venezuelan savanna atmosphere, measurements of gases and particles, chemical composition of rain, and biogenic soil emission were made during burning and nonburning periods at several rural savanna sites. A review of the most significant findings is presented in this chapter, and their regional and global implications are discussed

  2. Ecological release in lizard assemblages of neotropical savannas.

    Science.gov (United States)

    Mesquita, Daniel Oliveira; Colli, Guarino Rinaldi; Vitt, Laurie J

    2007-08-01

    We compare lizard assemblages of Cerrado and Amazonian savannas to test the ecological release hypothesis, which predicts that niche dimensions and abundance should be greater in species inhabiting isolated habitat patches with low species richness (Amazonian savannas and isolated Cerrado patches) when compared with nonisolated areas in central Cerrado with greater species richness. We calculated microhabitat and diet niche breadths with data from 14 isolated Cerrado patches and Amazon savanna areas and six central Cerrado populations. Morphological data were compared using average Euclidean distances, and lizard abundance was estimated using the number of lizards captured in pitfall traps over an extended time period. We found no evidence of ecological release with respect to microhabitat use, suggesting that historical factors are better microhabitat predictors than ecological factors. However, data from individual stomachs indicate that ecological release occurs in these areas for one species (Tropidurus) but not others (Ameiva ameiva, Anolis, Cnemidophorus, and Micrablepharus), suggesting that evolutionary lineages respond differently to environmental pressures, with tropidurids being more affected by ecological factors than polychrotids, teiids, and gymnophthalmids. We found no evidence that ecological release occurs in these areas using morphological data. Based on abundance data, our results indicate that the ecological release (density compensation) hypothesis is not supported: lizard species are not more abundant in isolated areas than in nonisolated areas. The ecology of species is highly conservative, varying little from assemblage to assemblage. Nevertheless, increases in niche breadth for some species indicate that ecological release occurs as well.

  3. Microbial Diversity in Cerrado Biome (Neotropical Savanna Soils.

    Directory of Open Access Journals (Sweden)

    Alinne Pereira de Castro

    Full Text Available The Cerrado, the largest savanna region in South America, is located in central Brazil. Cerrado physiognomies, which range from savanna grasslands to forest formations, combined with the highly weathered, acidic clay Cerrado soils form a unique ecoregion. In this study, high-throughput sequencing of ribosomal RNA genes was combined with shotgun metagenomic analysis to explore the taxonomic composition and potential functions of soil microbial communities in four different vegetation physiognomies during both dry and rainy seasons. Our results showed that changes in bacterial, archaeal, and fungal community structures in cerrado denso, cerrado sensu stricto, campo sujo, and gallery forest soils strongly correlated with seasonal patterns of soil water uptake. The relative abundance of AD3, WPS-2, Planctomycetes, Thermoprotei, and Glomeromycota typically decreased in the rainy season, whereas the relative abundance of Proteobacteria and Ascomycota increased. In addition, analysis of shotgun metagenomic data revealed a significant increase in the relative abundance of genes associated with iron acquisition and metabolism, dormancy, and sporulation during the dry season, and an increase in the relative abundance of genes related to respiration and DNA and protein metabolism during the rainy season. These gene functional categories are associated with adaptation to water stress. Our results further the understanding of how tropical savanna soil microbial communities may be influenced by vegetation covering and temporal variations in soil moisture.

  4. Being stressed outside the park — conservation of African elephants (Loxodonta africana) in Namibia

    OpenAIRE

    Hunninck, Louis; Ringstad, Iris; Jackson, Craig Ryan; May, Roelof Frans; Fossøy, Frode; Uiseb, Kenneth; Killian, Werner; Røskaft, Eivin

    2017-01-01

    The conservation of the African savanna elephant (Loxodonta africana) is of prime importance for many African countries. Interactions between elephants and humans are known to induce stress and thereby have the potential to affect elephants’ fitness. In Namibia, anthropogenic disturbances are increasing due to increasing human population size and development, particularly near protected areas, such as national parks. In this study, we investigated elephant stress levels in relation to their l...

  5. Morphological and functional diversity of primary producers group in savannas

    International Nuclear Information System (INIS)

    Medina, E.

    1996-01-01

    The meaning of biological diversity for the operation and stability of natural ecosystems is matter of great theoretical and practical interest. The appearance and permanency of species in a given atmosphere indicates its capacity to compete with other species with similar habit and requirements, and to accumulate the resources that allow its reproduction. On the other hand, the coexistence of similar species in the same ecosystem allows to wonder if ever biological redundancy exists, that is to say, if several species coexist with the same function inside the ecosystem, so that the disappearance of one of them would not have biological significant consequences. A strategy to simplify the analysis of relationships between biodiversity and ecosystems operation is by grouping species with similar function, called functional groups. In this work the the primary producers functional group is analyzed, essentially superiors plants, in a savannas ecosystems. The analysis establishes that the gives the primary producers group is heterogeneous and complex, so much morphological as functionally: 1) the structural complexity and diversity forms of life in an savannas ecosystem are associated with the stratified exploitation of resources over (light) and under the floor (nourishment and water). Changes in diversity that affect the system structure will probably also affect its operations. 2 )Very similar morphological species can differ physiologically up to constitute production units with contrasting nutritional requirements. The echo-physiologic analysis of this differentiation can explain the habitat preferences that are naturally observed. 3) The long-time permanency of rare species, of low frequency, show the inability of dominant species to capture all the available resources. 4) The primary producers and the floor microorganisms have strong interactions. Changes in the community composition can generate significant changes in other community. These biotic interactions

  6. Multilocus phylogeography of a widespread savanna-woodland-adapted rodent reveals the influence of Pleistocene geomorphology and climate change in Africa's Zambezi region.

    Science.gov (United States)

    McDonough, Molly M; Šumbera, Radim; Mazoch, Vladimír; Ferguson, Adam W; Phillips, Caleb D; Bryja, Josef

    2015-10-01

    Understanding historical influences of climate and physiographic barriers in shaping patterns of biodiversity remains limited for many regions of the world. For mammals of continental Africa, phylogeographic studies, particularly for West African lineages, implicate both geographic barriers and climate oscillations in shaping small mammal diversity. In contrast, studies for southern African species have revealed conflicting phylogenetic patterns for how mammalian lineages respond to both climate change and geologic events such as river formation, especially during the Pleistocene. However, these studies were often biased by limited geographic sampling or exclusively focused on large-bodied taxa. We exploited the broad southern African distribution of a savanna-woodland-adapted African rodent, Gerbilliscus leucogaster (bushveld gerbil) and generated mitochondrial, autosomal and sex chromosome data to quantify regional signatures of climatic and vicariant biogeographic phenomena. Results indicate the most recent common ancestor for all G. leucogaster lineages occurred during the early Pleistocene. We documented six divergent mitochondrial lineages that diverged ~0.270-0.100 mya, each of which was geographically isolated during periods characterized by alterations to the course of the Zambezi River and its tributaries as well as regional 'megadroughts'. Results demonstrate the presence of a widespread lineage exhibiting demographic expansion ~0.065-0.035 mya, a time that coincides with savanna-woodland expansion across southern Africa. A multilocus autosomal perspective revealed the influence of the Kafue River as a current barrier to gene flow and regions of secondary contact among divergent mitochondrial lineages. Our results demonstrate the importance of both climatic fluctuations and physiographic vicariance in shaping the distribution of southern African biodiversity. © 2015 John Wiley & Sons Ltd.

  7. ISSN 2073 ISSN 2073 9990 East Cent. Afr. J. 9990 East Cent. Afr. J ...

    African Journals Online (AJOL)

    Hp 630 Dual Core

    COSECSA/ASEA Publication East and Central African ... the one hand on medical technology and equipment and on the other hand on the medical .... traumatic brain injury was the main cause of death amongst emergency admissions at the.

  8. Spatial co-distribution of neglected tropical diseases in the East African Great Lakes region: revisiting the justification for integrated control

    Science.gov (United States)

    Clements, Archie C. A.; Deville, Marie-Alice; Ndayishimiye, Onésime; Brooker, Simon; Fenwick, Alan

    2010-01-01

    Summary OBJECTIVE To determine spatial patterns of co-endemicity of schistosomiasis mansoni and the soil-transmitted helminths (STHs) Ascaris lumbricoides, Trichuris trichiura and hookworm in the Great Lakes region of East Africa, to help plan integrated neglected tropical disease programmes in this region. METHOD Parasitological surveys were conducted in Uganda, Tanzania, Kenya and Burundi in 28 213 children in 404 schools. Bayesian geostatistical models were used to interpolate prevalence of these infections across the study area. Interpolated prevalence maps were overlaid to determine areas of co-endemicity. RESULTS In the Great Lakes region, prevalence was 18.1% for Schistosoma mansoni, 50.0% for hookworm, 6.8% for A. lumbricoides and 6.8% for T. trichiura. Hookworm infection was ubiquitous, whereas S. mansoni, A. lumbricoides and T. trichiura were highly focal. Most areas were endemic (prevalence ≥10%) or hyperendemic (prevalence ≥50%) for one or more STHs, whereas endemic areas for schistosomiasis mansoni were restricted to foci adjacent large perennial water bodies. CONCLUSION Because of the ubiquity of hookworm, treatment programmes are required for STH throughout the region but efficient schistosomiasis control should only be targeted at limited high-risk areas. Therefore, integration of schistosomiasis with STH control is only indicated in limited foci in East Africa. PMID:20409287

  9. Bistability, Spatial Interaction, and the Distribution of Tropical Forests and Savannas

    NARCIS (Netherlands)

    Staal, Arie; Dekker, Stefan C.; Xu, Chi; Nes, van Egbert H.

    2016-01-01

    Recent work has indicated that tropical forest and savanna can be alternative stable states under a range of climatic conditions. However, dynamical systems theory suggests that in case of strong spatial interactions between patches of forest and savanna, a boundary between both states is only

  10. Plant composition in oak savanna and woodland restoration at Prairie Fork Conservation Area in Missouri

    Science.gov (United States)

    Nadia E. Navarrete-Tindall; J.W. Van Sambeek; Jamie Coe; Warren Taylor

    2007-01-01

    The wooded areas of the Prairie Fork Conservation Area in central Missouri are typical of the oak/hickory forest/prairie transition zone that will require active management to restore pre-settlement, grass dominated savannas and open woodlands to improve habitat for wildlife. We initiated a management program to restore savannas and woodlands by reducing the midstory (...

  11. Tree invasion in a semi-arid savanna in Zimbabwe : seedling recruitment of Acacia karroo

    NARCIS (Netherlands)

    Chirara, C. (Chipangura)

    2001-01-01

    In this thesis Chirara reports on his study on the competitive interaction between savanna grasses and young tree seedlings of Acacia karroo, from hereon indicated as ' Acacia seedlings' . Acacia is one of the tree species that dominates savanna grassland in situations of overgrazing (bush

  12. Pattern of invasion by Adhatoda vasica in savannas of Sariska Tiger Reserve, Rajasthan, Western India

    NARCIS (Netherlands)

    Bhatt, Priyanka; Rawat, G.S.; Sankar, K.; Tomlinson, K.W.; Langevelde, van F.

    2015-01-01

    As part of global experiments on Savanna vegetation, we examined the ecological characteristics of an important
    semiarid savanna in the Indian sub-continent i.e Sariska Tiger Reserve, Rajasthan, Western India during April 2009 to
    May 2011. 149 plots across five line transects were sampled

  13. Heaths and forests of the western hills of Chia, Bogota savanna, Colombia

    International Nuclear Information System (INIS)

    Cortes S, Sandra P.; Van der Hammen, Thomas; Rangel Ch, J Orlando

    2000-01-01

    The authors make a study of the heaths and forests of the western hills of the population of Chia, located in the savanna of Bogota and the presence or absences of these in the same Bogota savanna; the authors treat topics like their physiognomy and composition, distribution and ecology among other topics

  14. Tectonic inheritance in the development of the Kivu - north Tanganyika rift segment of the East African Rift System: role of pre-existing structures of Precambrian to early Palaeozoic origin.

    Science.gov (United States)

    Delvaux, Damien; Fiama Bondo, Silvanos; Ganza Bamulezi, Gloire

    2017-04-01

    The present architecture of the junction between the Kivu rift basin and the north Tanganyika rift basin is that of a typical accommodation zone trough the Ruzizi depression. However, this structure appeared only late in the development of the Western branch of the East African Rift System and is the result of a strong control by pre-existing structures of Precambrian to early Palaeozoic origin. In the frame of a seismic hazard assessment of the Kivu rift region, we (Delvaux et al., 2016) constructed homogeneous geological, structural and neotectonic maps cross the five countries of this region, mapped the pre-rift, early rift and Late Quaternary faults and compiled the existing knowledge on thermal springs (assumed to be diagnostic of current tectonic activity along faults). We also produced also a new catalogue of historical and instrumental seismicity and defined the seismotectonic characteristics (stress field, depth of faulting) using published focal mechanism data. Rifting in this region started at about 11 Ma by initial doming and extensive fissural basaltic volcanism along normal faults sub-parallel to the axis of the future rift valley, as a consequence of the divergence between the Nubia and the Victoria plate. In a later stage, starting around 8-7 Ma, extension localized along a series of major border faults individualizing the subsiding tectonic basins from the uplifting rift shoulders, while lava evolved towards alkali basaltic composition until 2.6 Ma. During this stage, initial Kivu rift valley was extending linearly in a SSW direction, much further than its the actual termination at Bukavu, into the Mwenga-Kamituga graben, up to Namoya. The SW extremity of this graben was linked via a long oblique transfer zone to the central part of Lake Tanganyika, itself reactivating an older ductile-brittle shear zone. In the late Quaternary-early Holocene, volcanism migrated towards the center of the basin, with the development of the Virunga volcanic massif

  15. Early Pliocene anuran fossils from Kanapoi, Kenya, and the first fossil record for the African burrowing frog Hemisus (Neobatrachia: Hemisotidae).

    Science.gov (United States)

    Delfino, Massimo

    2017-07-13

    Isolated amphibian bones from the early Pliocene of Kanapoi (West Turkana, Kenya) help to improve the scarce fossil record of the late Neogene and Quaternary amphibians from East Africa. All currently available 579 bones are referable exclusively to the Anura (frogs and toads). More than half of the remains (366) are identified as Hemisus cf. Hemisus marmoratus, an extant species that still inhabits Kenya, but apparently not the northwest of the country and the Turkana area in particular. The rest of the remains are identified simply as Anura indet. because of poor preservation or non congruence with the relatively few African extant taxa whose osteology is known in detail. The Hemisus material represents the first fossil record for Hemisotidae, an endemic African family of peculiar, head-first burrowing frogs, whose sister taxon relationships indicate a divergence from brevicipitids in the Late Cretaceous or early Paleocene. The ecological requirements of extant H. marmoratus suggest that the Kanapoi area surrounding the fluvial and deltaic settings, from where the fossil remains of vertebrates were buried, was likely a grassland or relatively dry, open low tree-shrub savanna. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Impacts of Human Activities on Tree Species Composition Along the Forest Savanna Boundary in Nigeria

    Directory of Open Access Journals (Sweden)

    Christiana Ndidi Egbinola

    2016-02-01

    Full Text Available The study investigated the tree species composition along the forest-savanna boundary in Oyo state of Nigeria with the aim of assessing the impact of human activities on the floristic composition. A transect was placed along the study area and species data was collected from quadrats placed in study plots within different study sites. Detrended Correspondence Analysis (DCA was used to determine vegetation assemblages, while both correlation and the analysis of variance (ANOVA were used to show the relationship between species in the different study sites. Results of the DCA revealed three species assemblages, an area with only forest species, another with only savanna species and a third with both forest/savanna species. ANOVA results further revealed that within the forest and savanna assemblages, species in mature and successional sites were alike. The study therefore revealed that human activities’ within the region is leading to the establishment of savanna species and an elimination of forest species.

  17. Fluxes of CH4 and CO2 from soil and termite mounds in south Sudanian savanna of Burkina Faso (West Africa)

    Science.gov (United States)

    Brümmer, Christian; Papen, Hans; Wassmann, Reiner; Brüggemann, Nicolas

    2009-03-01

    The contribution of West African savanna ecosystems to global greenhouse gas budgets is highly uncertain. In this study we quantified soil-atmosphere CH4 and CO2 fluxes in the southwest of Burkina Faso from June to September 2005 and from April to September 2006 at four different agricultural fields planted with sorghum (n = 2), cotton, and peanut and at a natural savanna site with termite (Cubitermes fungifaber) mounds. During the rainy season both CH4 uptake and CH4 emission were observed in the savanna, which was on average a CH4 source of 2.79 and 2.28 kg CH4-C ha-1 a-1 in 2005 and 2006, respectively. The crop sites were an average CH4 sink of -0.67 and -0.70 kg CH4-C ha-1 a-1 in the 2 years, without significant seasonal variation. Mean annual soil respiration ranged between 3.86 and 5.82 t CO2-C ha-1 a-1 in the savanna and between 2.50 and 4.51 t CO2-C ha-1 a-1 at the crop sites. CH4 emission from termite mounds was 2 orders of magnitude higher than soil CH4 emissions, whereas termite CO2 emissions were of the same order of magnitude as soil CO2 emissions. Termite CH4 and CO2 release in the savanna contributed 8.8% and 0.4% to the total soil CH4 and CO2 emissions, respectively. At the crop sites, where termite mounds had been almost completely removed because of land use change, termite fluxes were insignificant. Mound density-based upscaling of termite CH4 fluxes resulted in a global termite CH4 source of 0.9 Tg a-1, which corresponds to 0.15% of the total global CH4 budget of 582 Tg a-1, hence significantly lower than those obtained previously by biomass-based calculations. This study emphasizes that land use change, which is of high relevance in this region, has particularly affected soil CH4 fluxes in the past and might still do so in the future.

  18. Horizontal and vertical variability of soil moisture in savanna ecosystems

    Science.gov (United States)

    Caylor, K.; D'Odorico, P.; Rodriguez-Iturbe, I.

    2004-12-01

    Soil moisture is a key hydrological variable that mediates the interactions between climate, soil, and vegetation dynamics in water-limited ecosystems. Because of the importance of water limitation in savannas, a number of theoretical models of tree-grass coexistence have been developed which differ in their underlying assumptions about the ways in which trees and grasses access and use soil moisture. However, clarification of the mechanisms that allow savanna vegetation to persist as a mixture of grasses and trees remains a vexing problem in both hydrological and vegetation science. A particular challenge is the fact that the spatial pattern of vegetation is both a cause and effect of variation in water availability in semiarid ecosystems. At landscape to regional scales, climatic and geologic constraints on soil moisture availability are primary determinants of vegetation structural pattern. However, at local to landscape scales the patchy vegetation structural mosaic serves to redistribute the availability of soil moisture in ways that have important consequences for structural dynamics and community composition. In this regard, the emerging field of ecohydrology is well suited to investigate questions concerning couplings between the patchy structural mosaic of savanna vegetation and the kinds self-organizing dynamics known to exist in other light and nutrient-limited vegetation systems. Here we address the role of patchy vegetation structure through the use of a lumped model of soil moisture dynamics that accounts for the effect of tree canopy on the lateral and vertical distribution of soil moisture. The model includes mechanisms for the drying of the ground surface due to soil evaporation in the sites with no tree cover, and for the lateral water uptake due to root invading areas with no canopy cover located in the proximity of trees. The model, when applied to a series of sites along a rainfall gradient in southern Africa, is able to explain the cover

  19. Performance of MIDAS Over East African Longitude Sector: Case Study During 4-14 March 2012 Quiet to Disturbed Geomagnetic Conditions

    Science.gov (United States)

    Giday, Nigussie M.; Katamzi-Joseph, Zama T.

    2018-02-01

    This study investigates the performance of a tomographic algorithm, Multi-Instrument and Data Analysis System (MIDAS), during an extended period of 4-14 March 2012, containing moderate and strong geomagnetic storms conditions, over an understudied and data scarce Eastern African longitude sector. Nonetheless, a relatively better distribution of Global Navigation Satellite Systems stations exists along a narrow longitude sector between 30°E and 44°E and latitude range of 30°S and 36°N that spans the equatorial, middle-, and low-latitude ionosphere. Then results are compared with independent global models such as International Reference Ionosphere 2012 (IRI-2012) and global ionosphere map (GIM). MIDAS performance was better than that of the IRI-2012 and GIM models in terms of capturing the diurnal trends as well as the short temporal total electron content (TEC) structures, with least root-mean-square errors (RMSEs). Overall, MIDAS results showed better agreement with the observation vertical TEC (VTEC) with computed maximum correlation coefficient (r) of 0.99 and minimum root-mean-square error (RMSE) of 2.91 TEC unit (1 TECU = 1,016 el m-2 over all the test stations and the validation days. Conversely, for the IRI-2012 and GIM TEC estimates, the corresponding maximum computed r values were 0.93 and 0.99, respectively, while the minimum RMSEs were 13.03 TECU and 6.52 TECU, respectively, for all the test stations and the validation days.

  20. MARKET OF NON-WOOD FOREST PRODUCTS FROM BRAZILIAN SAVANNA

    Directory of Open Access Journals (Sweden)

    Sandra Regina Afonso

    2009-10-01

    Full Text Available In this article, we analyze the main non-wood forest products from Brazilian savanna. We studied the behavior and the growth rates of production and prices of almond of babaçu, oil of copaiba, fiber of buriti, leaf of jaborandi, bark of barbatimão, bark of angico, fruit of mangaba, almonds of pequi, from 1982 to 2005. All the products exhibited decreasing production, with exception of the oil of copaiba and almonds of pequi, which showed positive growth rates: 12.9% and 8.5%, respectively. The analysis of prices for most products was not significant, except for barks of barbatimão and angico, and almonds of pequi, which showed positive trends: 10.9%, 6.7%, and 4.6%, respectively. We believe that results were not significant due to the severe variations of the Brazilian currency in the period. We conclude that pequi is the main product from savanna and that oil of copaiba has the biggest increase in the production because most of the production comes from the whole Brazilian Amazon region.

  1. Seasonal variation of ground spiders in a Brazilian Savanna

    Directory of Open Access Journals (Sweden)

    Marina Farcic Mineo

    2010-06-01

    Full Text Available The Brazilian Savanna Ecoregion (Cerrado is one of the richest biomes in the world, with a characteristic highly seasonal climate a dry season between May and September and a rainy season from October through April. Ground-dwelling spiders from three Cerrado phytophysiognomies, "campo cerrado", "cerrado" and "cerrad��o", were sampled using pitfall traps during two years, totaling 111 species and 3,529 individuals. The abundance of individuals and species richness was higher during the wet season. Fifty-eight species were captured exclusively during that period, whereas only nineteen were restricted to the dry season. Only two species were found in all samples. The number of juveniles was higher than the number of adults in all phytophysiognomies and in all species during both seasons. The highest abundance was registered in October and the lowest in April. Overall sex ratio was male-biased in all vegetation types sampled. Distinct climate variables affected the abundance of spiders depending on sex, age and vegetal physiognomy where they were sampled. This study involved the longest sampling of spider abundance and diversity on the ground of a Brazilian Savanna.

  2. Institutional capacity for health systems research in East and Central African schools of public health: experiences with a capacity assessment tool.

    Science.gov (United States)

    Jessani, Nasreen; Lewy, Daniela; Ekirapa-Kiracho, Elizabeth; Bennett, Sara

    2014-06-02

    Despite significant investments in health systems research (HSR) capacity development, there is a dearth of information regarding how to assess HSR capacity. An alliance of schools of public health (SPHs) in East and Central Africa developed a tool for the self-assessment of HSR capacity with the aim of producing institutional capacity development plans. Between June and November 2011, seven SPHs across the Democratic Republic of Congo, Ethiopia, Kenya, Rwanda, Tanzania, and Uganda implemented this co-created tool. The objectives of the institutional assessments were to assess existing capacities for HSR and to develop capacity development plans to address prioritized gaps. A mixed-method approach was employed consisting of document analysis, self-assessment questionnaires, in-depth interviews, and institutional dialogues aimed at capturing individual perceptions of institutional leadership, collective HSR skills, knowledge translation, and faculty incentives to engage in HSR. Implementation strategies for the capacity assessment varied across the SPHs. This paper reports findings from semi-structured interviews with focal persons from each SPH, to reflect on the process used at each SPH to execute the institutional assessments as well as the perceived strengths and weaknesses of the assessment process. The assessment tool was robust enough to be utilized in its entirety across all seven SPHs resulting in a thorough HSR capacity assessment and a capacity development plan for each SPH. Successful implementation of the capacity assessment exercises depended on four factors: (i) support from senior leadership and collaborators, (ii) a common understanding of HSR, (iii) adequate human and financial resources for the exercise, and (iv) availability of data. Methods of extracting information from the results of the assessments, however, were tailored to the unique objectives of each SPH. This institutional HSR capacity assessment tool and the process for its utilization

  3. Novel engineered HIV-1 East African Clade-A gp160 plasmid construct induces strong humoral and cell-mediated immune responses in vivo

    International Nuclear Information System (INIS)

    Muthumani, Karuppiah; Zhang Donghui; Dayes, Nathanael S.; Hwang, Daniel S.; Calarota, Sandra A.; Choo, Andrew Y.; Boyer, Jean D.; Weiner, David B.

    2003-01-01

    HIV-1 sequences are highly diverse due to the inaccuracy of the viral reverse transcriptase. This diversity has been studied and used to categorize HIV isolates into subtypes or clades, which are geographically distinct. To develop effective vaccines against HIV-1, immunogens representing different subtypes may be important for induction of cross-protective immunity, but little data exist describing and comparing the immunogenicity induced by different subtype-based vaccines. This issue is further complicated by poor expression of HIV structural antigens due to rev dependence. One costly approach is to codon optimize each subtype construct to be examined. Interestingly, cis-acting transcriptional elements (CTE) can also by pass rev restriction by a rev independent export pathway. We reasoned that rev+CTE constructs might have advantages for such expression studies. A subtype A envelope sequence from a viral isolate from east Africa was cloned into a eukaryotic expression vector under the control of the CMV-IE promoter. The utility of inclusion of the Mason-Pfizer monkey virus (MPV)-CTE with/without rev for driving envelope expression and immunogenicity was examined. Expression of envelope (gp120) was confirmed by immunoblot analysis and by pseudotype virus infectivity assays. The presence of rev and the CTE together increased envelope expression and viral infection. Furthermore the CTE+rev construct was significantly more immunogenic then CTE alone vector. Isotype analysis and cytokine profiles showed strong Th1 response in plasmid-immunized mice, which also demonstrated the superior nature of the rev+CTE construct. These responses were of similar or greater magnitude to a codon-optimized construct. The resulting cellular immune responses were highly cross-reactive with a HIV-1 envelope subtype B antigen. This study suggests a simple strategy for improving the expression and immunogenicity of HIV subtype-specific envelope antigens as plasmid or vector

  4. Causes of unrest at silicic calderas in the East African Rift: New constraints from InSAR and soil-gas chemistry at Aluto volcano, Ethiopia

    Science.gov (United States)

    Hutchison, William; Biggs, Juliet; Mather, Tamsin A.; Pyle, David M.; Lewi, Elias; Yirgu, Gezahegn; Caliro, Stefano; Chiodini, Giovanni; Clor, Laura E.; Fischer, Tobias P.

    2016-08-01

    Restless silicic calderas present major geological hazards, and yet many also host significant untapped geothermal resources. In East Africa, this poses a major challenge, although the calderas are largely unmonitored their geothermal resources could provide substantial economic benefits to the region. Understanding what causes unrest at these volcanoes is vital for weighing up the opportunities against the potential risks. Here we bring together new field and remote sensing observations to evaluate causes of ground deformation at Aluto, a restless silicic volcano located in the Main Ethiopian Rift (MER). Interferometric Synthetic Aperture Radar (InSAR) data reveal the temporal and spatial characteristics of a ground deformation episode that took place between 2008 and 2010. Deformation time series reveal pulses of accelerating uplift that transition to gradual long-term subsidence, and analytical models support inflation source depths of ˜5 km. Gases escaping along the major fault zone of Aluto show high CO2 flux, and a clear magmatic carbon signature (CO2-δ13C of -4.2‰ to -4.5‰). This provides compelling evidence that the magmatic and hydrothermal reservoirs of the complex are physically connected. We suggest that a coupled magmatic-hydrothermal system can explain the uplift-subsidence signals. We hypothesize that magmatic fluid injection and/or intrusion in the cap of the magmatic reservoir drives edifice-wide inflation while subsequent deflation is related to magmatic degassing and depressurization of the hydrothermal system. These new constraints on the plumbing of Aluto yield important insights into the behavior of rift volcanic systems and will be crucial for interpreting future patterns of unrest.

  5. Environmental determinants of tropical forest and savanna distribution: A quantitative model evaluation and its implication

    Science.gov (United States)

    Zeng, Zhenzhong; Chen, Anping; Piao, Shilong; Rabin, Sam; Shen, Zehao

    2014-07-01

    The distributions of tropical ecosystems are rapidly being altered by climate change and anthropogenic activities. One possible trend—the loss of tropical forests and replacement by savannas—could result in significant shifts in ecosystem services and biodiversity loss. However, the influence and the relative importance of environmental factors in regulating the distribution of tropical forest and savanna biomes are still poorly understood, which makes it difficult to predict future tropical forest and savanna distributions in the context of climate change. Here we use boosted regression trees to quantitatively evaluate the importance of environmental predictors—mainly climatic, edaphic, and fire factors—for the tropical forest-savanna distribution at a mesoscale across the tropics (between 15°N and 35°S). Our results demonstrate that climate alone can explain most of the distribution of tropical forest and savanna at the scale considered; dry season average precipitation is the single most important determinant across tropical Asia-Australia, Africa, and South America. Given the strong tendency of increased seasonality and decreased dry season precipitation predicted by global climate models, we estimate that about 28% of what is now tropical forest would likely be lost to savanna by the late 21st century under the future scenario considered. This study highlights the importance of climate seasonality and interannual variability in predicting the distribution of tropical forest and savanna, supporting the climate as the primary driver in the savanna biogeography.

  6. Using Paleoecology to Inform Land Management as Climates Change: An Example from an Oak Savanna Ecosystem

    Science.gov (United States)

    Spencer, Jessica D.; Brunelle, Andrea; Hepola, Tim

    2017-12-01

    Oak savanna, a transitional ecosystem between open prairie and dense oak forest, was once widespread in Minnesota. Upon European settlement much of the oak savanna was destroyed. Recently, efforts to restore this ecosystem have increased and often include the reintroduction of fire. Though fire is known to serve an important role within oak savannas, there are currently few studies which address fire regimes on timescales longer than the last century. This research presents a paleoecological history of Sherburne National Wildlife Refuge (SNWR) in MN, USA, spanning the last 8000 years. The objectives of this study were to use charcoal, pollen, and magnetic susceptibility of lake sediments collected from Johnson Slough (JS) within the refuge to evaluate the natural range of variability and disturbance history of the oak savanna within the refuge, assess the success of current restoration strategies, and add to the regional paleoecological history. The mid/late Holocene period of the JS record shows a period of high fire activity from ca. 6500 to 2600 cal year BP, with a shift from prairie to oak savanna occurring over this same period. A (possibly agricultural) disturbance to JS sediments affected the period from ca. 2600 cal year BP to 1963 AD, which includes the time of Euro-American settlement. However, the destruction and subsequent restoration of the oak savanna is evident in a pollen ratio of Quercus:Poaceae, indicating that current restoration efforts have been successful at restoring the oak savanna to within the natural range of variability seen just prior to destruction.

  7. African Journals Online: Browse Alphabetically -- letter E

    African Journals Online (AJOL)

    Items 1 - 39 of 39 ... The East African Journal of Sciences (EAJS) publishes original ... The objects of the Association journal shall be the advancement of the science and art of ..... Economics, Business Management, and Public Administration and ...

  8. African Journal of Clinical and Experimental Microbiology

    African Journals Online (AJOL)

    African Journal of Clinical and Experimental Microbiology. ... of edible locally produced dry season leafy vegetables cultivated in south east Enugu, Nigeria ... Cross-seasonal analysis of bacteriological profile of water sources as a disease risk ...

  9. Ecological thresholds in the savanna landscape: developing a protocol for monitoring the change in composition and utilisation of large trees.

    Directory of Open Access Journals (Sweden)

    Dave J Druce

    Full Text Available BACKGROUND: Acquiring greater understanding of the factors causing changes in vegetation structure -- particularly with the potential to cause regime shifts -- is important in adaptively managed conservation areas. Large trees (> or =5 m in height play an important ecosystem function, and are associated with a stable ecological state in the African savanna. There is concern that large tree densities are declining in a number of protected areas, including the Kruger National Park, South Africa. In this paper the results of a field study designed to monitor change in a savanna system are presented and discussed. METHODOLOGY/PRINCIPAL FINDINGS: Developing the first phase of a monitoring protocol to measure the change in tree species composition, density and size distribution, whilst also identifying factors driving change. A central issue is the discrete spatial distribution of large trees in the landscape, making point sampling approaches relatively ineffective. Accordingly, fourteen 10 m wide transects were aligned perpendicular to large rivers (3.0-6.6 km in length and eight transects were located at fixed-point photographic locations (1.0-1.6 km in length. Using accumulation curves, we established that the majority of tree species were sampled within 3 km. Furthermore, the key ecological drivers (e.g. fire, herbivory, drought and disease which influence large tree use and impact were also recorded within 3 km. CONCLUSIONS/SIGNIFICANCE: The technique presented provides an effective method for monitoring changes in large tree abundance, size distribution and use by the main ecological drivers across the savanna landscape. However, the monitoring of rare tree species would require individual marking approaches due to their low densities and specific habitat requirements. Repeat sampling intervals would vary depending on the factor of concern and proposed management mitigation. Once a monitoring protocol has been identified and evaluated, the next

  10. ICDP Project DeepCHALLA: Reconstructing 250,000 Years of Climate Change and Environmental History on the East African Equator

    Science.gov (United States)

    Wolff, C.; Verschuren, D.; Van Daele, M. E.; Waldmann, N.; Meyer, I.; Lane, C. S.; Van der Meeren, T.; Ombori, T.; Kasanzu, C.; Olago, D.

    2017-12-01

    (inter-annual to decadal) and long (glacial-interglacial) time scales; and to assess the multi-faceted impact of this climate change on the region's freshwater resources, the functioning of terrestrial ecosystems, and the history of the African landscape in which modern humans (our species, Homo sapiens) originally evolved and have lived ever since.

  11. Inferences of Present and Past Changes at Isolated Enclaves and Matrix of Savannas by Carbon Isotopes in a Transitional Forest-Savanna Area in Northern Amazonia

    Science.gov (United States)

    Couto-Santos, F. R.; Luizao, F. J.; Camargo, P. B.

    2013-12-01

    The evolutionary history of savannas influenced by short term climate cycles, during the Quaternary Period, could prompt variations in forest cover often related to movements of the forest-savanna boundary. In this study we investigated current and past changes in the structure of vegetation and the origins of savannas of different natures in a biogeographically and climatic transitional forest-savanna area in northern Amazonia. Variations in the isotopic composition of soil organic matter (δ13C) from surface soils (0-10 cm) along forest-savanna boundaries, detected by a sigmoidal non-linear function, were used to identify current changes in vegetation, while past changes were inferred by discontinuities in the evolution of δ13C with soil depth using piecewise regression associated with radiocarbon dating (14C). By comparing small isolated savanna enclaves inside a strictly protected nature reserve (ESEC Maracá) with its outskirts unprotected continuous savanna matrix, we found that origins and the patterns of dynamics were distinct between these areas and did not respond in the same way to climate change and fire events, either in the last decades or during the Holocene. The stability of the present boundaries of the surrounding savanna matrix reflects the resilience of the transitional forests under a recent intensified fire regime and favorable climate, while the deep forest soil isotopic signal indicated a forest shrinkage of at least 70 m occurring since its origin in early Holocene until 780 years BP associated with a climate drier than the current one. Contrarily, the protected enclaves inside ESEC Maracá, remained stable since the middle Holocene, suggesting a non-anthropogenic origin related to soil edaphic conditions, but with recent dynamics of advancing forest by 8 m century-1 favored by current climate and lacking fire events. A detailed understanding of the origins of savannas of distinct natures and the way they are affected by climate and fire

  12. Matrix-assisted laser desorption/ionization time of flight mass spectrometry for comprehensive indexing of East African ixodid tick species.

    Science.gov (United States)

    Rothen, Julian; Githaka, Naftaly; Kanduma, Esther G; Olds, Cassandra; Pflüger, Valentin; Mwaura, Stephen; Bishop, Richard P; Daubenberger, Claudia

    2016-03-15

    The tick population of Africa includes several important genera belonging to the family Ixodidae. Many of these ticks are vectors of protozoan and rickettsial pathogens including Theileria parva that causes East Coast fever, a debilitating cattle disease endemic to eastern, central and southern Africa. Effective surveillance of tick-borne pathogens depends on accurate identification and mapping of their tick vectors. A simple and reproducible technique for rapid and reliable differentiation of large numbers of closely related field-collected ticks, which are often difficult and tedious to discriminate purely by morphology, will be an essential component of this strategy. Matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) is increasingly becoming a useful tool in arthropod identification and has the potential to overcome the limitations of classical morphology-based species identification. In this study, we applied MALDI-TOF MS to a collection of laboratory and field ticks found in Eastern Africa. The objective was to determine the utility of this proteomic tool for reliable species identification of closely related afrotropical ticks. A total of 398 ixodid ticks from laboratory maintained colonies, extracted from the hides of animals or systematically collected from vegetation in Kenya, Sudan and Zimbabwe were analyzed in the present investigation. The cytochrome c oxidase I (COI) genes from 33 specimens were sequenced to confirm the tentatively assigned specimen taxa identity on the basis of morphological analyses. Subsequently, the legs of ticks were homogenized and analyzed by MALDI-TOF MS. A collection of reference mass spectra, based on the mass profiles of four individual ticks per species, was developed and deposited in the spectral database SARAMIS™. The ability of these superspectra (SSp.) to identify and reliably validate a set of ticks was demonstrated using the remaining individual 333 ticks. Ultimately, ten

  13. Management of Herbaceous Seeps and Wet Savannas for Threatened and Endangered Species

    National Research Council Canada - National Science Library

    Harper, Mary

    1998-01-01

    Wetland communities such as herbaceous seeps and wet savannas occur on military installations throughout the southeastern United States, usually as pockets of wet habitat within a matrix of drier longleaf pine woodlands...

  14. Hyper-temporal c-band SAR for baseline woody structural assessments in deciduous savannas

    CSIR Research Space (South Africa)

    Mathieu, Renaud SA

    2016-08-01

    Full Text Available deciduous savanna environment. Results showed that: the temporal filter reduced image variance; the random forest model out-performed the linear model; while the TCV metric consistently showed marginally higher accuracies than the TCC metric. Combinations...

  15. Mapping big tree presence in open savanna, using tree shadow and high resolution multispectral imagery

    CSIR Research Space (South Africa)

    Mathieu, Renaud SA

    2012-10-01

    Full Text Available Large scattered trees play an important role in the functioning of savanna landscapes. They act as focal points for various organism activities, which influence the distribution of nutrients and water within the landscape, which in turn influences...

  16. Global extent and determinants of savanna and forest as alternative biome states

    CSIR Research Space (South Africa)

    Staver, C

    2011-10-01

    Full Text Available Theoretically, fire–tree cover feedbacks can maintain savanna and forest as alternative stable states. However, the global extent of fire- driven discontinuities in tree cover is unknown, especially accounting for seasonality and soils. The authors...

  17. Factors influencing local ecological knowledge of forage resources: Ethnobotanical evidence from West Africa's savannas.

    Science.gov (United States)

    Naah, John-Baptist S N; Guuroh, Reginald T

    2017-03-01

    Recording local ecological knowledge (LEK) is a useful approach to understanding interactions of the complex social-ecological systems. In spite of the recent growing interest in LEK studies on the effects of climate and land use changes, livestock mobility decisions and other aspects of agro-pastoral systems, LEK on forage plants has still been vastly under-documented in the West African savannas. Using a study area ranging from northern Ghana to central Burkina Faso, we thus aimed at exploring how aridity and socio-demographic factors drive the distributional patterns of forage-related LEK among its holders. With stratified random sampling, we elicited LEK among 450 informants in 15 villages (seven in Ghana and eight in Burkina Faso) via free list tasks coupled with ethnobotanical walks and direct field observations. We performed generalized linear mixed-effects models (aridity- and ethnicity-based models) and robust model selection procedures. Our findings revealed that LEK for woody and herbaceous forage plants was strongly influenced by the ethnicity-based model, while aridity-based model performed better for LEK on overall forage resources and crop-related forage plants. We also found that climatic aridity had negative effect on the forage-related LEK across gender and age groups, while agro- and floristic diversity had positive effect on the body of LEK. About 135 species belonging to 95 genera and 52 families were cited. Our findings shed more light on how ethnicity and environmental harshness can markedly shape the body of LEK in the face of global climate change. Better understanding of such a place-based knowledge system is relevant for sustainable forage plants utilization and livestock production. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Impacts of landuse and climate change on the dynamics and biodiversity in the Thornbush Savanna Biome

    CSIR Research Space (South Africa)

    Jeltsch, F

    2010-01-01

    Full Text Available pressure on dryland ecosystem services takes place in regions of intermediate aridity and not, as might be expected, in dry subhumid ar- eas where population density is highest, or in hyperarid areas, where population is lowest. The high... of households (Ericson & Watson 2009). They can function as a model-region for a broad range of dry- lands, especially non-humid savannas, worldwide?in particular as projected climatic changes for most subhumid and semiarid savanna regions indicate major...

  19. Eye Munchausen's Syndrome: Case Report | Atipo-Tsiba | East ...

    African Journals Online (AJOL)

    East African Medical Journal. Journal Home · ABOUT THIS ... Munchausen's syndrome is a psychiatric disorder characterised by a need to simulate a disease or trauma self-mutilation, in order to attract attention or sympathy. Patients with this ...

  20. Gastric outlet obstruction in Northwestern Ethiopia | Kotisso | East ...

    African Journals Online (AJOL)

    East and Central African Journal of Surgery. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 5, No 2 (2000) >. Log in or Register to get access to full text downloads.

  1. Gastric cancers at Kibogora Hospital | Ntakiyiruta | East and Central ...

    African Journals Online (AJOL)

    East and Central African Journal of Surgery. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 14, No 1 (2009) >. Log in or Register to get access to full text downloads.

  2. Creating opportunities for youth in East Africa | IDRC - International ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2016-06-30

    Jun 30, 2016 ... Youth employment is crucial to the development of the East African ... Even those with university degrees and college diplomas often fall ... However, the study shows that there is limited awareness of the benefits of career ...

  3. ISSN 2073-9990 East Cent. Afr. J. surg. (Online)

    African Journals Online (AJOL)

    dell

    COSECSA/ASEA Publication -East and Central African Journal of Surgery April .... toward skeletal muscle, cartilage, fibrous tissue, and sometimes fat, and most ... ipsilateral lobes of the lung, the central nervous system including the spinal ...

  4. Menstruation in Rural Igbo Women of South East Nigeria: Attitudes ...

    African Journals Online (AJOL)

    Menstruation in Rural Igbo Women of South East Nigeria: Attitudes, Beliefs and Practices. ... African Journal of Reproductive Health ... Some respondents observed self-imposed restrictions on exercises, food items, visits and sex in order to ...

  5. African Trypanosomiasis

    Science.gov (United States)

    2011-06-01

    sedimentation rate and immunoglobulins, especially IgM. The CSF contains increased protein and mononuclear cells (about 5% of which are plasma cells...confined to rural areas, in dense vegetation along streams and lakes (T. b. gambiense) (Fig 3.2), or wooded areas of the savanna (T. b. rhodesiense...Flagellum extends posteriorly along outer border of undulating membrane . Giemsa x1300 Figure 3.4 Long slender form and short stumpy form of

  6. The individual and interactive effects of tree-tree establishment competition and fire on savanna structure and dynamics

    OpenAIRE

    Calabrese, Justin; Vázquez, Federico; López, Cristóbal; San Miguel, Maxi; Grimm, Volker

    2010-01-01

    The mechanisms regulating savanna tree populations are still not well understood. Recent empirical work suggests that both tree-tree competition and fire are key factors in semi-arid to mesic savannas. However, the potential for competition to structure savannas, particularly in interaction with fire, has received little theoretical attention. We develop a minimalistic and analytically tractable stochastic cellular automaton to study the individual and combined effects of competition and fire...

  7. AfricaArray seismological studies of the structure and evolution of the African continent

    CSIR Research Space (South Africa)

    Durrheim, RJ

    2013-10-01

    Full Text Available and Madagascar. Brandt and Mulibo elucidated the relationship between the African Superplume, Superswell and the East African Rift System by studying the seismic velocity structure of the mantle. Kgaswane jointly inverted P-wave receiver functions (PRFs...

  8. The springboks in East Africa: the role of 1 SA Survey Company ...

    African Journals Online (AJOL)

    The springboks in East Africa: the role of 1 SA Survey Company (SAEC) in the East African campaign of World War II, 1940–1941. ... Scientia Militaria: South African Journal of Military Studies ... As a member of the British Commonwealth, South Africa was part of Britain's war effort from September 1939 onward. When Italy ...

  9. Women Engagement with Power and Authority in Re-writing East ...

    African Journals Online (AJOL)

    From the relative absence of serious women writing in the early mainstream East African literature in English, starting the last quarter of the twentieth century, women writing has flourished to gain deserved space in the East African literary canon. In the writing of Kenya's Marjorie Oludhe Macgoye, Uganda's Mary Karooro ...

  10. Perceptions and Misperceptions: The Middle East and South Africa.

    Science.gov (United States)

    Moore, Michael; Tyson, G. A.

    1990-01-01

    Reports findings of a study examining the opinions and awareness level of South African, Israeli, and United States undergraduates about conflicts in either the Middle East or South Africa. Finds religious and racial characteristics determining differences in knowledge level and political support. Reveals South African Blacks and U.S. students…

  11. Obsidian dating and East african archeology.

    Science.gov (United States)

    Michels, J W; Tsong, I S; Nelson, C M

    1983-01-28

    New experimental procedures have made it possible to establish specific hydration rates for the numerous compositional types of obsidian to be found at archeological sites in Kenya. Two rates are applied to artifacts from the Prospect Farm site, revealing a history of occupation extending back 120,000 years.

  12. East African Journal of Statistics: Editorial Policies

    African Journals Online (AJOL)

    Focus and Scope. EAJOSTA publishes the latest finding in applied and theoretical statistics. The journal also accepts papers in operations research, financial mathematics and acturial sciences, all considered as part of applied statistics. Articles must deal with original research, which have not been accepted for publication ...

  13. East African Medical Journal: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  14. Towards a Description of East African Gestures

    Science.gov (United States)

    Creider, Chet A.

    1977-01-01

    This paper describes the gestural behavior of four tribal groups, Kipsigis, Luo, Gusii, and Samburu, observed and elicted in the course of two and one-half years of field work in Western Kenya in 1970-72. The gestures are grouped into four categories: (1) initiators and finalizers of interaction; (2) imperatives; (3) responses; (4) qualifiers.…

  15. December 2004 EAST AFRICAN MEDICAL JOURNAL 641

    African Journals Online (AJOL)

    2004-12-01

    Dec 1, 2004 ... GENDER AND WILLINGNESS TO PAY FOR INSECTICIDES TREATED BED NETS IN A POOR RURAL AREA IN .... the same taste for prevention of mosquito bites and ..... Studies have found' that the systematic income gap.

  16. East African Orthopaedic Journal: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  17. East African Journal of Sciences: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  18. East African Journal of Statistics: Advanced Search

    African Journals Online (AJOL)

    Search tips: Search terms are case-insensitive; Common words are ignored; By default only articles containing all terms in the query are returned (i.e., AND is implied); Combine multiple words with OR to find articles containing either term; e.g., education OR research; Use parentheses to create more complex queries; e.g., ...

  19. East and Central African Journal of Surgery

    African Journals Online (AJOL)

    School were made guinea pigs for a new syllabus of English Language for Scientists. As I remember it now, the course consisted of exercises whereby masses of scientific data had to be analyzed and the results .expressed in good ... reviewed journal open to submission of papers from. In those days of relative prosperity, ...

  20. Scopus: Journal of East African Ornithology: Submissions

    African Journals Online (AJOL)

    Author Guidelines. Contributions. Contributions comprise original papers, short communications (usually less than two pages), short notes and records, notices and letters. Original papers and short ... Free access to current and recent issues; https://www.ajol.info/index.php/scopus/index. Free access to issues from ...