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1

The rise of injecting drug use in east Africa: a case study from Kenya  

PubMed Central

Studies on injecting drug use in East Africa are reviewed. The existingstudies document the spread of heroin injection in Kenya and Tanzania, both countries where HIV rates are high. No data from Uganda on injecting drug use was found by the authors. A case study of the growth of heroin injection in a Kenyan coastal town is presented. The need for needle-exchange programmes and other prevention services is discussed.

Beckerleg, Susan; Telfer, Maggie; Hundt, Gillian Lewando

2005-01-01

2

Ecology and taxonomy of a tree-living freshwater crab (Brachyura: Potamoidea: Potamonautidae) from Kenya and Tanzania, East Africa  

Microsoft Academic Search

The ecology and taxonomy of an interesting species of tree-living freshwater crab from the East Usambara mountains, Tanzania, and from the Shimba Hills, Kenya, East Africa is described. This phytotelmic decapod crustacean belongs to a new species of potamonautid freshwater crab in the genus Potamonautes MacLeay, 1838, which is described. This is one of only a few reports of the

Neil Cumberlidge; Marco Vannini

2004-01-01

3

Structural framework and denudation history of the flanks of the Kenya and Anza Rifts, East Africa  

NASA Astrophysics Data System (ADS)

The Kenya Rift in central Kenya (between ˜1° and 2° north latitude) is flanked by vast areas of Proterozoic crystalline rock where traditional stratigraphic markers useful for constraining Mesozoic to Recent structures are absent. Apatite fission track age and length data from about 100 samples collected from (1) relief profiles in north-south trending mountain ranges, and (2) east-west transects between mountain ranges constrain the structural framework of Cretaceous through Tertiary faulting in these flanking areas. Data from the profiles reveal regionally consistent age/elevation trends characterized by three distinct intervals, of 600 to 1200 m altitude, within which the apatite apparent ages are nearly concordant. The three isochronous age/elevation intervals yield apparent ages of ˜180, ˜115, and ˜65 Ma and record times of cooling starting at ?220, 140-120, and 70-60 Ma. We interpret the cooling to be related to episodes of relatively rapid denudation separated in time by periods of slower exhumation. The isochronous intervals of crust are regionally consistent and relative offsets between the intervals allow fault displacements and block tilts to be estimated, when used in conjunction with the variation of fission track age and length along the transects. The fault block geometry revealed by the displaced isochronous layers indicates that normal faults related to rifting, with relative displacements >1 km, extend at least 100 km east of the Kenya Rift Valley. The data indicate a consistent direction of block tilting for the segment of the rift studied, which is similar to the asymmetric extension observed for other sections of the East Africa Rift System and other narrow rifts. The regional block faulting in this area probably occurred during early to middle Tertiary time associated with the late stages of extension in the Anza Rift and/or the early stages of extension of the Kenya Rift, in a setting similar to the present morphology of northern Tanzania. Therefore focusing of faulting within a central rift valley in Kenya appears to have followed a phase of regional extension with minor total strain.

Foster, David A.; Gleadow, Andrew J. W.

1996-04-01

4

East African Rift Valley, Kenya  

NASA Technical Reports Server (NTRS)

This rare, cloud free view of the East African Rift Valley, Kenya (1.5N, 35.5E) shows a clear view of the Turkwell River Valley, an offshoot of the African REift System. The East African Rift is part of a vast plate fracture which extends from southern Turkey, through the Red Sea, East Africa and into Mozambique. Dark green patches of forests are seen along the rift margin and tea plantations occupy the cooler higher ground.

1990-01-01

5

Stable isotope composition of tropical high-altitude fresh-waters on Mt. Kenya, Equatorial East Africa  

Microsoft Academic Search

The stable isotope composition of equatorial high-altitude precipitation and surface-water bodies has been studied on Mt. Kenya (0°10?S; 37°20?E) in East Africa during July 1997. Regarding the local hydrology, glacier meltwater was identified as the main source of replenishment for the lakes, while direct precipitation and runoff appear to have a negligible contribution during this period of the year. Two

Miri Rietti-Shati; Ruth Yam; Wibjorn Karlen; Aldo Shemesh

2000-01-01

6

Risk factors of visceral leishmaniasis in East Africa: a case-control study in Pokot territory of Kenya and Uganda  

PubMed Central

Summary Background: In East Africa, visceral leishmaniasis (VL) is endemic in parts of Sudan, Ethiopia, Somalia, Kenya and Uganda. It is caused by Leishmania donovani and transmitted by the sandfly vector Phlebotomus martini. In the Pokot focus, reaching from western Kenya into eastern Uganda, formulation of a prevention strategy has been hindered by the lack of knowledge on VL risk factors as well as by lack of support from health sector donors. The present study was conducted to establish the necessary evidence-base and to stimulate interest in supporting the control of this neglected tropical disease in Uganda and Kenya. Methods: A case-control study was carried out from June to December 2006. Cases were recruited at Amudat hospital, Nakapiripirit district, Uganda, after clinical and parasitological confirmation of symptomatic VL infection. Controls were individuals that tested negative using a rK39 antigen-based dipstick, which were recruited at random from the same communities as the cases. Data were analysed using conditional logistic regression. Results: 93 cases and 226 controls were recruited into the study. Multivariate analysis identified low socio-economic status and treating livestock with insecticide as risk factors for VL. Sleeping near animals, owning a mosquito net and knowing about VL symptoms were associated with a reduced risk of VL. Conclusions: VL affects the poorest of the poor of the Pokot tribe. Distribution of insecticide-treated mosquito nets combined with dissemination of culturally appropriate behaviour-change education is likely to be an effective prevention strategy.

Kolaczinski, Jan H; Reithinger, Richard; Worku, Dagemlidet T; Ocheng, Andrew; Kasimiro, John; Kabatereine, Narcis; Brooker, Simon

2009-01-01

7

Large scale climatological controls of the mass balance of tropical Lewis Glacier, Mt Kenya, East Africa  

Microsoft Academic Search

Among other effects on the mass and energy balance, tropical glaciers are particularly sensitive to precipitation, which increases both mass accumulation and albedo (and thus reduces ablation). Therefore, precipitation variability is directly linked to mass balance variability. Multi-year and inter-annual fluctuations in large scale climate patterns (IOZM, ENSO) are known to strongly correlate with precipitation variability in equatorial East Africa,

Rainer Prinz; Lindsey Nicholson; Thomas Mölg; Ben Marzeion; Georg Kaser

2010-01-01

8

The Effect of Plume Impingement on Lithospheric Preservation Beneath the Kenya Rift, East Africa  

NASA Astrophysics Data System (ADS)

The Kenya Rift is located at the transition between Archean Tanzanian craton and Proterozoic mobile belt. Currently, discrepancies exist between geochemical and geophysical interpretations of lithospheric preservation in the Kenya Rift. Seismic data show a sharp vertical boundary between low velocity mantle in the axis and higher velocity mantle on the flanks, which is interpreted to reflect lithospheric erosion from the axis (Mechie et al., 1997; Prodehl et al., 1997). However, geochemical data suggest that the lithospheric mantle is intact beneath both the axis and the flanks. Different elemental groups are observed for rocks from Kenya (Hamblock et al., 2003). One group is characterized by elemental concentrations greater than ocean island basalts (OIB), negative K and Sr anomalies, and Lan and Cen greater than 100. These characteristics are found in silica-undersaturated rocks such as nephelinites, basanites, and some alkali basalts from the flank and the axis and are interpreted to represent melting of an enriched lithosphere. A second group is characterized by elemental concentrations less than OIB, a flat overall pattern, and Lan and Cen less than 100. This pattern is found in alkali basalts and hypersthene-normative rocks. The multi-element pattern varies minimally between axis and flank lavas, with axial lavas containing higher concentrations of Ba (Macdonald et al., 2001). Because rocks of both groups are present in the axis and the flanks, lithosphere appears to be intact across the Kenya Rift, and strong lateral contrasts in composition do not exist. Sr, Nd, and Pb isotopes also suggest that ancient lithospheric mantle is present in Kenya and Tanzania (Macdonald et al., 2001; Paslick et al., 1995). A consistent difference between axis and flank is lower La/Yb for axis lavas, indicating that they originate in the spinel stability field. Flank lavas, regardless of their silica saturation, have higher La/Yb and are interpreted to come from garnet peridotite. Discrepancies between geophysical and geochemical data exist for other parts of the East African Rift as well. In the axis of the rift in Tanzania, tomography suggests that upwelling asthenosphere has eroded the lithosphere (Nyblade, 2002). However, gravity models (Simiyu and Keller, 1997, 2001) and the presence of subchondritic 187Os/188Os in spinel and garnet-bearing xenoliths (TRD of 2.6 Ga) suggest that the lithosphere is intact (Chesley et al., 1999). In contrast, for the Tanzanian craton, Os isotopes, gravity, and tomography are consistent with 2.5-2.9 Ga lithosphere existing to depths of 140 km and a broad thermal and geochemical anomaly (plume?) below the lithosphere (Chesley et al., 1999; Owens et al., 2000; Nyblade et al., 2000; Simiyu and Keller, 1997, 2001). In the Sidamo region of Ethiopia, Os isotopes suggest that ancient depleted mantle is present and has been modified by recent melt percolation (Lorand et al., 2003; Reisberg et al., in press). Finally, for Ethiopian flood basalts, element chemistry, petrology, and 3He/4He (Marty et al., 1996; Scarsi and Craig, 1996) indicate a dominant role for plume. Os isotopes (Davies et al., 2003), however, are lower than PUM, indicating that an ancient lithospheric mantle reservoir is present. In order to help resolve the discrepancies between geophysical and geochemical interpretations, we will obtain petrologic and isotopic data for xenoliths and mafic lavas in both east-west and north-south directions. The lavas span a wide range of silica saturation and La/Yb ratios, and thus are intended to represent lithospheric as well as asthenospheric sources.

Hamblock, J. M.; Anthony, E. Y.; Chesley, J. T.; Omenda, P. A.

2003-12-01

9

East Africa  

NASA Technical Reports Server (NTRS)

This image shows the East African nations of Ethiopia, Eritrea, and Somalia, as well as portions of Kenya, Sudan, Yemen, and Saudi Arabia. Dominating the scene are the green Ethiopian Highlands. With altitudes as high as 4,620 meters (15,157 feet), the highlands pull moisture from the arid air, resulting in relatively lush vegetation. In fact, coffee-one of the world's most prized crops-originated here. To the north (above) the highlands is Eritrea, which became independent in 1993. East (right) of Ethiopia is Somalia, jutting out into the Indian Ocean. The Sea-viewing Wide Field-of-view Sensor (SeaWiFS) captured this true-color image on November 29, 2000. Provided by the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

2002-01-01

10

Recent land?cover\\/use change associated with land degradation in the Lake Baringo catchment, Kenya, East Africa: evidence from Landsat TM and ETM+  

Microsoft Academic Search

Many parts of East Africa are experiencing dramatic changes in land?cover\\/use at a variety of spatial and temporal scales, due to both climatic variability and human activities. Information about such changes is often required for planning, management, and conservation of natural resources. Several methods for land cover\\/change detection using Landsat TM\\/ETM+ imagery were employed for Lake Baringo catchment in Kenya,

L. M. Kiage; N. D. Walker; N. Lam; O. K. Huh

2007-01-01

11

The Effect of Plume Impingement on Lithospheric Preservation Beneath the Kenya Rift, East Africa  

Microsoft Academic Search

The Kenya Rift is located at the transition between Archean Tanzanian craton and Proterozoic mobile belt. Currently, discrepancies exist between geochemical and geophysical interpretations of lithospheric preservation in the Kenya Rift. Seismic data show a sharp vertical boundary between low velocity mantle in the axis and higher velocity mantle on the flanks, which is interpreted to reflect lithospheric erosion from

J. M. Hamblock; E. Y. Anthony; J. T. Chesley; P. A. Omenda

2003-01-01

12

Antibodies to Neospora caninum in wild animals from Kenya, East Africa  

Microsoft Academic Search

The prevalence of antibodies to Neospora caninum was examined in six wild Artiodactyla species, and in five wild Carnivora species from Kenya. Blood sera (104 wild ungulates from Marula Estates (MEs), and 31 wild carnivores from Masai-Mara reserve and from other wildlife areas in northern and Southern Kenya), were screened using a Neospora agglutination test (NAT), with a twofold dilution

E Ferroglio; E Wambwa; M Castiello; A Trisciuoglio; A Prouteau; E Pradere; S Ndungu; D De Meneghi

2003-01-01

13

Distribution and abundance of freshwater crabs ( Potamonautes spp.) in rivers draining Mt Kenya, East Africa  

Microsoft Academic Search

Little is known about population densities of freshwater crabs, or their ecological importance, in Afri­ can rivers. This study aimed to quantify crab abundance in rivers draining Mt Kenya. Invertebrates were sampled from 21 sites on 19 rivers. Sample sites were divided into: open sites in agricultural land from which trees were mainly absent; shaded sites, in agricultural land, with

Michael Dobson; Adiel M. Magana; Jude M. Mathooko; Fidensio K. Ndegwa

2007-01-01

14

TDRS satellite over African Rift Valley, Kenya, Africa  

NASA Technical Reports Server (NTRS)

This post deploy view of a TDRS satellite shows a segment of the African Rift Valley near Lake Baringo, Kenya, Africa (3.0S, 36.0E). The African Rift Valley system is a geologic fault having its origins in southern Turkey, through the near east forming the bed of the Jordan River, Gulf of Aqaba, the Red Sea and down through east Africa. The line of lakes and valleys of east Africa are the result of the faulting activity.

1983-01-01

15

Antibodies to Neospora caninum in wild animals from Kenya, East Africa.  

PubMed

The prevalence of antibodies to Neospora caninum was examined in six wild Artiodactyla species, and in five wild Carnivora species from Kenya. Blood sera (104 wild ungulates from Marula Estates (MEs), and 31 wild carnivores from Masai-Mara reserve and from other wildlife areas in northern and Southern Kenya), were screened using a Neospora agglutination test (NAT), with a twofold dilution (1:40-1:320 titres). Presence of NAT antibodies to N. caninun is reported here for the first time in zebra (Equus burchelli), eland (Taurotragus oryx), African buffalo (Syncerus caffer), Thompson gazelle (Gazella thompsoni), impala (Aepyceros melampus), warthog (Phacochoerus aethiopicus), spotted hyena (Crocuta crocuta) and in free-ranging cheetah (Acinonyx jubatus). At 1:80 dilution, prevalence was 61.5% in eland, 58.5% in zebra, 19.2% in Thompson gazelle, 33.3% in warthog, 50% in African buffalo, 30% in lion (Panthera leo), 20% in cheetah, and 33.3% in spotted hyena. Antibodies up to 1:320 titre were detected in eland (38.4%), zebra (19.5%), Thompson gazelle (3.8%) and lion (5%). Amongst herbivores, sero-prevalence was significantly (P<0.05) higher, at all dilutions, in "grazer/digger" species (e.g. eland and zebra) than in non-"grazer/digger" species (e.g. impala and Thompson gazelle). No antibodies to N. caninum were found in two leopards (Panthera pardus) and one serval (Felis serval). Our results indicates a steady presence of N. caninum in wild mammals from Kenya. The hypothesis of a sylvatic cycle of N. caninum could be suggested, but more data are needed to verify the hypothesis, as to evaluate the role of N. caninum infection on the dynamics of wild animals population in the study area. PMID:14651874

Ferroglio, E; Wambwa, E; Castiello, M; Trisciuoglio, A; Prouteau, A; Pradere, E; Ndungu, S; De Meneghi, D

2003-12-01

16

The Sun Rises in the East (of Africa): A Comparison of the Development and Status of the Solar Energy Markets in Kenya and Tanzania  

Microsoft Academic Search

This paper describes, compares and analyses the historical development and current status of Kenya's and Tanzania's emerging solar energy markets. The analysis is based on an extensive literature survey and 25 in-depth personal interviews with experts on the East African solar power market. Kenya's solar market is found to be one of the world's leading markets for off-grid solar uses,

Janosch Ondraczek

2012-01-01

17

A Wrench fault system and nappe emplacement in Southern Kenya and Northern Tanzania.- A key area for Pan-African continental collision in East Africa?  

Microsoft Academic Search

In the Voi Area of Southern Kenya, the granulite facies rocks of the Taita Hills and the Tsavo East National Park (Galana River) can be divided into three structural domains: The Galana-East unit consists of an intercalation of flat lying metapelites and marbles of continental margin origin. These metasediments can be traced further east to the Umba Steppe (Between Mombasa

A. Bauernhofer; E. Wallbrecher; C. Hauzenberger; H. Fritz; J. Loizenbauer; G. Hoinkes; S. Muhongo; E. Mathu

2003-01-01

18

Sediment infill within rift basins: Facies distribution and effects of deformation: Examples from the Kenya and Tanganyika Rifts, East Africa  

SciTech Connect

Oil is known from lacustrine basins of the east African rift. The geology of such basins is complex and different depending on location in the eastern and western branches. The western branch has little volcanism, leading to long-lived basins, such as Lake Tanganyika, whereas a large quantity of volcanics results in the eastern branch characterized by ephemeral basins, as the Baringo-Bogoria basin in Kenya. The Baringo-Bogoria basin is a north-south half graben formed in the middle Pleistocene and presently occupied by the hypersaline Lake Bogoria and the freshwater Lake Baringo. Lake Bogoria is fed by hot springs and ephemeral streams controlled by grid faults bounding the basin to the west. The sedimentary fill is formed by cycles of organic oozes having a good petroleum potential and evaporites. On the other hand, and as a consequence of the grid faults, Lake Baringo is fed by permanent streams bringing into the basin large quantities of terrigenous sediments. Lake Tanganyika is a meromictic lake 1470 m deep and 700 km long, of middle Miocene age. It is subdivided into seven asymmetric half grabens separated by transverse ridges. The sedimentary fill is thick and formed by organic oozes having a very good petroleum potential. In contrast to Bogoria, the lateral distribution of organic matter is characterized by considerable heterogeneity due to the existence of structural blocks or to redepositional processes.

Tiercelin, J.J.; Lezzar, K.E. (Universite de Bretagne Occidentale, Brest (France)); Richert, J.P. (Elf Aquitaine, Pau (France))

1994-07-01

19

Recent changes in the level of Lake Naivasha, Kenya, as an indicator of equatorial westerlies over East Africa  

Microsoft Academic Search

A previously unpublished record of lake levels from Lake Naivasha, Kenya from 1880 to 1976 has been analysed and shows little similarity to the level record from nearby Lake Victoria. Level changes from year to year of the two lakes show no significant correlation (at 5%) and spectral analysis of the two records shows no common significant peaks. Both lakes

C. E. Vincent; T. D. Davies; A. K. C. Beresford

1979-01-01

20

Late Quaternary vegetation changes around Lake Rutundu, Mount Kenya, East Africa: evidence from grass cuticles, pollen and stable carbon isotopes  

Microsoft Academic Search

Woody, subalpine shrubs and grasses currently surround Lake Rutundu, Mount Kenya. Multiple proxies, including carbon isotopes, pollen and grass cuticles, from a 755-cm-long core were used to reconstruct the vegetation over the past 38 300 calendar years. Stable carbon-isotope ratios of total organic carbon and terrestrial biomarkers from the lake sediments imply that the proportion of terrestrial plants using the

M. J. Wooller; D. L. Swain; K. J. Ficken; A. D. Q. Agnew; G. Eglinton

2003-01-01

21

A new species of arboreal forest-dwelling gecko (Hemidactylus: Squamata: Gekkonidae) from coastal Kenya, East Africa.  

PubMed

A new species of Hemidactylus, H. mrimaensis sp. nov., is described from coastal kaya forests of Kenya. This small-sized, arboreal gecko may be distinguished from its probable close relative, the sympatric H. mabouia, by its more slender habitus, golden color, small adult body length (maximum SVL 50 mm in females) and features of scalation including keeled dorsal tubercles in 11-14 longitudinal rows, pointed tubercles on tail larger than those on the dorsum, and 32-34 precloacal pores in males. This gecko may be endemic to the coastal forests and given the ongoing threats to this habitat, the species is of high conservation concern. PMID:24869535

Malonza, Patrick K; Bauer, Aaron M

2014-01-01

22

Smallholder dairying under transactions costs in East Africa  

Microsoft Academic Search

It is argued that dairying is vital to future viability of many small farms in East Africa and that high transactions costs for dairy production and marketing limit participation by asset- and information-poor smallholders. Case studies from Kenya and Ethiopia illustrate the role of dairy cooperatives in reducing transactions costs. Analysis of the determinants of producer prices received by a

Charles Nicholson; Christopher Delgado

1997-01-01

23

Maximizing the impact of print media in church development in the Presbyterian Church of East Africa (P.C.E.A.) (Kenya)  

Microsoft Academic Search

According to the report of the Communications Committee of the Presbyterian Church of East Africa (P.C.E.A.) to the 15th General Assembly, the church is aware of the immensity of information, education and revelation that can be shared and disseminated through the print media in the church. 1 However, to effectively disseminate the Gospel through the print media requires some creativity

James Mwangi Munyi

1997-01-01

24

Chronology of the Later Stone Age and Food Production in East Africa  

Microsoft Academic Search

Evidence from several archaeological sites in sub-Saharan Africa suggests that the transition to modern human technology, marked by the change from the Middle to the Later Stone Age (LSA), occurred first in East Africa. Enkapune Ya Muto rockshelter, in the central Rift Valley of Kenya, contains the oldest known archaeological horizons spanning this transition. Radiocarbon and obsidian hydration dates from

Stanley H. Ambrose

1998-01-01

25

Developing a Systemic Approach to Teacher Education in Sub-Saharan Africa: Emerging Lessons from Kenya, Tanzania and Uganda  

ERIC Educational Resources Information Center

While many countries in Eastern and Southern Africa are on track for meeting the Education for All targets, there is a growing recognition of the need to improve the quality of basic education and that a focus on pedagogy and its training implications needs to be at the heart of this commitment. By drawing on three East African countries, Kenya,…

Hardman, Frank; Ackers, Jim; Abrishamian, Niki; O'Sullivan, Margo

2011-01-01

26

Forecasting droughts in East Africa  

NASA Astrophysics Data System (ADS)

The humanitarian crisis caused by the recent droughts (2008-2009 and 2010-2011) in East Africa have illustrated that the ability to make accurate drought predictions with sufficient lead time is essential. The use of dynamical model forecasts in combination with drought indices, such as the Standardized Precipitation Index (SPI), can potentially to lead to a better description of drought duration, magnitude and spatial extent. This study evaluates the use of the European Centre for Medium-Range Weather Forecasts (ECMWF) products in forecasting droughts in East Africa. ECMWF seasonal precipitation shows significant skill for both rain seasons when evaluated against measurements from the available in-situ stations from East Africa. The forecast for October-December rain season has higher skill than for the March-May season. ECMWF forecasts add value to the statistical forecasts produced during the Greater Horn of Africa Climate Outlook Forums (GHACOF), which is the present operational product. Complementing the raw precipitation forecasts with SPI provides additional information on the spatial extent and intensity of the drought event.

Mwangi, Emmah; Wetterhall, Fredrik; Dutra, Emanuel; Di Giuseppe, Francesca; Pappenberger, Florian

2014-05-01

27

Information technology applications in East Africa government-owned university libraries  

Microsoft Academic Search

The information environment of a given society currently revolves around the ability to use and manipulate information technologies. This paper reviews the trend of information technology (IT) applications in East Africa government-owned university libraries for the ten years 1987-1997. By 1997, East Africa (Kenya, Tanzania, Uganda) had only eight government-owned university libraries. The trend of IT applications in those libraries

R. T. Mulimila

2000-01-01

28

East Africa continental margins  

SciTech Connect

New well data from Somalia, together with the history of sea-floor spreading in the Indian Ocean derived from magnetic anomalies, show that the East African margins from latitude 15/sup 0/S into the Gulf of Aden comprise four distinct segments that formed successively by the southward drift of Madagascar from Somalia during the Middle to Late Jurassic and Early Cretaceous, by the northeastward drift of India along the Owen Transform during the Late Cretaceous and Paleocene, and by the opening of the Gulf of Aden during the Neogene.

Bosellini, A.

1986-01-01

29

Holocene glaciations and paleoclimate of mount Kenya and other East African mountains  

NASA Astrophysics Data System (ADS)

This paper summarizes available glacial geological data including sediments, landforms, paleosols, and paleoclimate for major mountain areas in East Africa. From 1890 to the present a number of workers have tried, with varying degrees of success, to reconstruct Holocene glacial and paleoclimatic records. Most of the mountains are surfaced with late Pleistocene and late Holocene glacial sediments which are poorly dated, and in many cases stratigraphic units are only recognized by their topographic positions. Only on Mount Kenya is there an emerging glacial stratigraphy based on dating. Both Holocene and Pleistocene glacier fluctuations appear to have been broadly synchronous in the East African mountains. Terminal moraines on Mount Kenya extend to 3200 m in most drainage basins and yield minimum 14C ages of ˜15 ka BP. Recessional moraines, of Liki III age, at 3700-4200 m appear to date from the late glacial, (later Pleistocene; see Coetzee, 1967, for a discussion), while younger Neoglacial (see Mahaney, 1982, 1984 for a discussion) moraines are either 'Little Ice Age' in age, or are older late Holocene deposits. The Neoglacial sequence on Mount Kenya is younger than 1 ka BP, while on other East African mountains it may have commenced about 2 ka BP. Most of Holocene time appears to have been warmer, and perhaps wetter, than today, when glaciers disappeared altogether, or were distributed much as they are today.

Mahaney, William C.

30

Evaluating the Madrasa Preschool Programme in East Africa: A Quasi-Experimental Study  

ERIC Educational Resources Information Center

This study investigated the effect of preschool experience (two types of preschool: Madrasa and non-Madrasa) on the cognitive development of children in East Africa. In the three countries studied (Kenya, Uganda, and Tanzania/Zanzibar) preschool education is burgeoning and government standards are being set. This quasi experimental evaluation used…

Mwaura, Peter A. M.; Sylva, Kathy; Malmberg, Lars-Erik

2008-01-01

31

Evaluating the Madrasa preschool programme in East Africa: a quasi?experimental study  

Microsoft Academic Search

This study investigated the effect of preschool experience (two types of preschool: Madrasa and non?Madrasa) on the cognitive development of children in East Africa. In the three countries studied (Kenya, Uganda, and Tanzania\\/Zanzibar) preschool education is burgeoning and government standards are being set. This quasi experimental evaluation used four subscales (block building, verbal comprehension, early number concept, picture similarities) adapted

Peter A. M. Mwaura; Kathy Sylva

2008-01-01

32

The role of soil science in agricultural development in East Africa  

Microsoft Academic Search

Agriculture is the mainstay of the economy of the three countries of East Africa (Kenya, Tanzania and Uganda). It employs about 80 to 90 percent of the population of these countries and is also the main source of food and foreign exchange earnings. However, the agricultural development in the region has remained below expectation during the last five decades. Although

F. N. Muchena; R. M. Kiome

1995-01-01

33

Food biotechnology and nutrition in Africa: a case for Kenya.  

PubMed

Household food consumption surveys indicate that the diet in Kenya is ill balanced and that many families cannot afford nutrient-rich foods such as meat and fruits. In this regard, rural populations-the majority of the Kenyan population-are much worse off than urban populations. Agriculture, the most important sector in the Kenyan economy, contributes 27% of the gross domestic product and generates 65% of the country's export earnings. Food-enhancing biotechnologies thus could increase national food yields and fill nutrition gaps by contributing to household and national food security and poverty reduction in Kenya. To overcome barriers to adopting biotechnology to improve food crops in Kenya and elsewhere in Africa, policy makers must create a receptive environment for, increase public understanding of, and stimulate investment in the new technology. PMID:16619741

Ngichabe, Christopher K

2002-12-01

34

Development of a Testate Amoebae Calibration Dataset from a freshwater wetland in a semi-arid environment: Loboi Swamp, Kenya, East Africa.  

NASA Astrophysics Data System (ADS)

The East African Rift Valley is characterized as an arid to semi-arid region, with several large, well studied, alkaline lakes; within the region, freshwater wetlands persist. These wetland systems, locally are important sources of freshwater. They also provide overlooked important paleoclimate archives, as the fragile ecology of these wetlands can be affected by even minor changes in hydrology and climate. Loboi Swamp is a 1.5 km2 freshwater wetland located near the equator in the Kenyan Rift Valley. The region receives approximately 700 mm of precipitation per year, while potential evaporation exceeds 2500 mm annually. Analysis of 25-years of precipitation data from local weather stations indicate that significant positive precipitation anomalies occur during El Niño years. Radiocarbon, pollen, and diatom data from Loboi Swamp indicates that the current wetland developed approximately 700 years ago. Sediment surface samples were collected for pollen, seeds and testate amoebae, along with water chemistry and vegetation data from throughout the Loboi Marsh. In this paper we present preliminary data and results in the development of a calibration dataset to test the feasibility of using testate amoebae as a proxy for hydrological and geochemical changes in a semi-arid setting. Initial results indicate significant qualitative differences in testate amoebae taxon distribution within geographic regions of the marsh, which likely correlate with a variety of hydrologic parameters (e.g., alkalinity, PH, DO, and temperature).

Goman, M. F.; Ashley, G. M.; Hover, V. C.; Muasya, A. M.

2005-12-01

35

Leaf litter removal by the snail Terebralia palustris (Linnaeus) and sesarmid crabs in an East African mangrove forest (Gazi Bay, Kenya)  

Microsoft Academic Search

Quantitative data on leaf litter removal activity of macrozoobenthic organisms in the mangrove forests of East Africa are virtually non-existent. In the present study, litter removal activity was determined in two contrasting types of mangrove stands in Gazi Bay (Kenya). In the relatively elevated Ceriops tagal vegetation, which is only flooded during spring tides, the detritivorous snail Terebralia palustris (Linnaeus)

F. J Slim; M. A. Hemminga; C. Ochieng; N. T Jannink; E Cocheret de la Morinière; G. Van der Velde

1997-01-01

36

Investigating the Role of Poultry in Livelihoods and the Impact of HPAI on Livelihoods Outcomes in Africa: Evidence from Ethiopia, Ghana, Kenya and Nigeria  

Microsoft Academic Search

In this paper we investigate the role of poultry in the livelihoods portfolios of households and the impact of supply and demand shocks that may be caused by Highly Pathogenic Avian Influenza (HPAI) on various livelihoods outcomes of households in four Sub-Saharan African (SSA) countries. The study countries include Ethiopia and Kenya in East Africa and Ghana and Nigeria in

Ekin Birol; Dorene Asare-Marfo; Gezahegne Ayele; Akwasi Mensah-Bonsu; Lydia K. Ndirangu; Benjamin Okpukpara; Devesh Roy; Yorbol Yakhshilikov

2010-01-01

37

East and Southern Africa English Accents.  

ERIC Educational Resources Information Center

Discusses English pronunciation features in the anglophone countries of East and Southern Africa. Focus is on restructuring of the STRUT vowel to /a/,/i/, and /e/ epenthesis, and short tone groups.(Author/VWL)

Bobda, Augustin Simo

2001-01-01

38

Renewable Resource Trends in East Africa.  

National Technical Information Service (NTIS)

Expanding human and livestock population density, coupled with high urban growth rates, are pushing land and water capacities in East Africa to the breaking point. Woodland cover, grazing land, and arable soils are being lost, and dwindling food productio...

1984-01-01

39

A new species, Gazza squamiventralis , from the East Coast of Africa (Perciformes: Leiognathidae)  

Microsoft Academic Search

Gazza squamiventralis sp. nov. is described as the fifth species of the genus, based on the holotype and eight paratypes, 42–96 mm in standard\\u000a length, collected along the east coast of Africa, from Kenya to Mozambique. The species is similar to other congeners in general\\u000a appearance, differing clearly from them in having the ventrolateral surface of the body scaled anterior

Tsuyoshi Yamashita; Seishi Kimura

2001-01-01

40

Magnetotelluric studies in East Africa  

NASA Astrophysics Data System (ADS)

Since its introduction just over half a century ago, the magnetotelluric method has been used in a wide range of environments, both onshore and submarine, at a large number of length scales, and to tackle a huge variety of problems in the earth sciences, both applied and curiosity-driven. Electromagnetic fields are induced in the sub-surface by passive magnetic field sources originating from lightning strikes trapped in the ionospheric waveguide and from the solar wind interacting with the magnetosphere, which enables information on the sub-surface resistivity distribution to be derived. Measuring the tiny induced signals depends on the careful deployment of very sensitive equipment. These time series are then subject to careful selection and processing techniques in the frequency domain to make robust estimates of the tensor quantity embodying the resistivity information as a function of depth. Further processing and assessment of the data allows the practitioner to assess the minimum dimension of the underlying resistivity distribution consistent with the data. As if this wasn't enough, the inverse problem is extremely non-linear, even in the simplest case of resistivity purely a function of depth. Most modelling and interpretation thus proceeds by a combination of forward modelling and regularised inversion, with tests to assess the resolving depth of the data, and their sensitivity to certain features of the model, for example. After introducing the method, I will illustrate it with examples of experiments carried out in East Africa with which I've been involved, concentrating on two substantial inter-disciplinary studies in Ethiopia, one of the northern Main Ethiopian rift, and the other an on-going project studying magmatic and tectonic processes associated with a current rifting episode in Afar. The main target for magnetotellurics in these projects has been imaging partial melt and magma in the sub-surface. I will aim to show how the interpretation of the magnetotelluric results is aided by having access to complementary data, and how in turn the magnetotelluric information informs and assists in understanding other datasets and modelling.Dabbahu magmatic segment and volcano, Afar, Ethiopia

Whaler, K. A.

2012-12-01

41

Study of the genetic heterogeneity of SAT-2 foot-and-mouth disease virus in sub-Saharan Africa with specific focus on East Africa.  

PubMed

The epidemiology of serotype SAT-2 foot-and-mouth disease was investigated in sub-Saharan Africa by phylogenetic analysis using the 1D gene encoding the major antigenic determinant. Fourteen genotypes were identified of which three are novel and belong to East Africa, bringing the total number of genotypes for that region to eight. The genotypes clustered into three lineages that demonstrated surprising links between East, southern and south-western Africa. One lineage was unique to West Africa. These results established numerous incursions across country borders in East Africa and long term conservation of sequences for periods up to 41 years. Ethiopia, Kenya and Uganda have all experienced outbreaks from more than one unrelated strain, demonstrating the potential for new introductions. The amount of variation observed within this serotype nearly equalled that which was found between serotypes; this has severe implications for disease control using vaccination. PMID:18453238

Sahle, M; Dwarka, R M; Venter, E H; Vosloo, W

2007-12-01

42

Biogas - Bioenergy potential in East Africa.  

National Technical Information Service (NTIS)

The workshop is part of the project: 'Energy production from Sisal Waste in East Africa' sponsored by the Danish Energy Agency, an agency under the Danish Ministry of Environment and Energy. This project has been carried out in close cooperation between t...

1997-01-01

43

Radical Islam in East Africa.  

National Technical Information Service (NTIS)

Historically, Africa has not been a central theater in U.S. strategic planning. U.S. interests there have been viewed as marginal, and the threats to those interests have not been considered serious enough to require the deployment of significant resource...

A. Rabasa

2009-01-01

44

Temperature and malaria trends in highland East Africa.  

PubMed

There has been considerable debate on the existence of trends in climate in the highlands of East Africa and hypotheses about their potential effect on the trends in malaria in the region. We apply a new robust trend test to mean temperature time series data from three editions of the University of East Anglia's Climatic Research Unit database (CRU TS) for several relevant locations. We find significant trends in the data extracted from newer editions of the database but not in the older version for periods ending in 1996. The trends in the newer data are even more significant when post-1996 data are added to the samples. We also test for trends in the data from the Kericho meteorological station prepared by Omumbo et al. We find no significant trend in the 1979-1995 period but a highly significant trend in the full 1979-2009 sample. However, although the malaria cases observed at Kericho, Kenya rose during a period of resurgent epidemics (1994-2002) they have since returned to a low level. A large assembly of parasite rate surveys from the region, stratified by altitude, show that this decrease in malaria prevalence is not limited to Kericho. PMID:21935416

Stern, David I; Gething, Peter W; Kabaria, Caroline W; Temperley, William H; Noor, Abdisalan M; Okiro, Emelda A; Shanks, G Dennis; Snow, Robert W; Hay, Simon I

2011-01-01

45

Helicobacter pylori in Immigrants from East Africa  

PubMed Central

This study determines the prevalence of Helicobacter pylori infection in a group of immigrants from East Africa with dyspepsia symptoms. Costs of treatment (including financial costs, adverse effects of treatment, and complexity of care) are compared for empiric treatment and treatment guided by serologic testing. Of the symptomatic patients, 93% had H. pylori antibodies. Empiric treatment of all patients with dyspepsia could reduce the cost of care by approximately half, with minimal risk to uninfected patients.

Wang, Peiyi; Adair, Richard

1999-01-01

46

History of Sleeping Sickness in East Africa  

PubMed Central

The history of human sleeping sickness in East Africa is characterized by the appearance of disease epidemics interspersed by long periods of endemicity. Despite the presence of the tsetse fly in large areas of East Africa, these epidemics tend to occur multiply in specific regions or foci rather than spreading over vast areas. Many theories have been proposed to explain this phenomenon, but recent molecular approaches and detailed analyses of epidemics have highlighted the stability of human-infective trypanosome strains within these foci. The new molecular data, taken alongside the history and biology of human sleeping sickness, are beginning to highlight the important factors involved in the generation of epidemics. Specific, human-infective trypanosome strains may be associated with each focus, which, in the presence of the right conditions, can be responsible for the generation of an epidemic. Changes in agricultural practice, favoring the presence of tsetse flies, and the important contribution of domestic animals as a reservoir for the parasite are key factors in the maintenance of such epidemics. This review examines the contribution of molecular and genetic data to our understanding of the epidemiology and history of human sleeping sickness in East Africa.

Hide, Geoff

1999-01-01

47

Hepatitis A shifting epidemiology in the Middle East and Africa  

Microsoft Academic Search

Data on the endemicity of hepatitis A virus (HAV) infection in Africa and the Middle East are scant, but most of Africa appears to remain a high endemicity region, with the exception of subpopulations in some areas, e.g. White people in South Africa. Saudi Arabia is a model for the Middle East, and is a country in which shifting HAV

Haysam Tufenkeji

2000-01-01

48

Geographic trends in mangrove crab abundance in East Africa  

Microsoft Academic Search

The aim of this work was to determine the abundance of crabs inmangrove communities along a latitudinal gradient along the eastern coastof Africa from 4°S to 32°S. Surveys were made atMombasa (Kenya), Zanzibar (Tanzania), Maputo (Mozambique) and in theTranskei (South Africa). Crabs were estimated at three designated levelsin the mangroves by visual census using a common protocol, and numberswere converted

R. G. Hartnoll; S. Cannicci; W. D. Emmerson; S. Fratini; A. Macia; Y. Mgaya; F. Porri; R. K. Ruwa; J. P. Shunula; M. W. Skov; M. Vannini

2002-01-01

49

Late Cenozoic Moisture History of East Africa  

NASA Astrophysics Data System (ADS)

Lake sediments in 10 Ethiopian, Kenyan, and Tanzanian rift basins suggest that there were three humid periods at 2.7 to 2.5 million years ago (Ma), 1.9 to 1.7 Ma, and 1.1 to 0.9 Ma, superimposed on the longer-term aridification of East Africa. These humid periods correlate with increased aridity in northwest and northeast Africa and with substantial global climate transitions. These episodes could have had important impacts on the speciation and dispersal of mammals and hominins, because a number of key events, such as the origin of the genus Homo and the evolution of the species Homo erectus, took place in this region during that time.

Trauth, Martin H.; Maslin, Mark A.; Deino, Alan; Strecker, Manfred R.

2005-09-01

50

Public health laboratory systems development in East Africa through training in laboratory management and field epidemiology  

PubMed Central

Laboratories are integral to the delivery of quality health care and for public health functions; however laboratory systems and services are often neglected in resource-poor settings such as the East African region. In order to sustainably strengthen national laboratory systems in resource-poor countries, there is a need to train laboratory personnel to work in clinical as well as public health laboratories. In 2004,Kenya, Uganda, Tanzania, and South Sudan began training public health laboratory workers jointly with field epidemiologists in the Kenya Field Epidemiology and Laboratory Training Program (FELTP), and later through the Tanzania FELTP, as a strategy to strengthen public health laboratories. These programs train laboratory epidemiologists through a two-year public health leadership development course, and also offer various types of short course training for frontline staff. The FELTP laboratory graduates in Kenya, Tanzania, Uganda, and South Sudan are working in their respective countries to strengthen public health laboratory systems while the short course participants provide a pool of frontline implementers with the capacity to support the lower tiers of health systems, as well as serve as surge capacity for the regions and the national level. Through training competent public health laboratory workers, the East African ministries of health, in collaboration with other regional partners and stakeholders are now engaged in developing and implementing a holistic approach that will guarantee an overall strengthening of the health system by using well-trained public health laboratory leaders to drive the process. Strengthening public health laboratory medicine in East Africa is critical to improve health-care systems. The experience with the FELTP model in East Africa is a step in the right direction towards ensuring a stronger role for the laboratory in public health.

Mosha, Fausta; Oundo, Joseph; Mukanga, David; Njenga, Kariuki; Nsubuga, Peter

2011-01-01

51

Hydrocarbon potential of the Lamu basin of south-east Kenya  

SciTech Connect

The Lamu basin occupies the coastal onshore and offshore areas of south-east Kenya. This fault bounded basin formed as a result of the Paleozoic-early Mesozoic phase of rifting that developed at the onset of Gondwana dismemberment. The resultant graben was filled by Karroo (Permian-Early Jurassic) continental siliciclastic sediments. Carbonate deposits associated with the Tethyan sea invasion, dominate the Middle to Late Jurassic basin fill. Cessation of the relative motion between Madagascar and Africa in the Early Cretaceous, heralded passive margin development and deltaic sediment progradation until the Paleogene. Shallow seas transgressed the basin in the Miocene when another carbonate regime prevailed. The basin depositional history is characterized by pulses of transgressive and regressive cycles, bounded by tectonically enhanced unconformities dividing the total sedimentary succession into discrete megasequences. Source rock strata occur within Megasequence III (Paleogene) depositional cycle and were lowered into the oil window in Miocene time, when the coastal parts of the basin experienced the greatest amount of subsidence. The tectono-eustatic pulses of the Tertiary brought about source and reservoir strata into a spatial relationship in which hydrocarbons could be entrapped. A basement high on the continental shelf has potential for Karroo sandstone and Jurassic limestone reservoirs. Halokinesis of Middle Jurassic salt in Miocene time provides additional prospects in the offshore area. Paleogene deltaic sands occur in rotated listric fault blacks. A Miocene reef Play coincides with an Eocene source rock kitchen.

Nyagah, K.; Cloeter, J.J.; Maende, A. (National Oil Corp. of Kenya, Nairobi (Kenya))

1996-01-01

52

76 FR 55456 - The Trade and Investment Partnership for the Middle East and North Africa  

Federal Register 2010, 2011, 2012, 2013

...Partnership for the Middle East and North Africa AGENCY: Office of the United States...developments in the Middle East and North Africa (MENA) region, the President...the term ``2011 Middle East and North Africa Trade'' in the ``Type...

2011-09-07

53

The importance of context in delivering effective EIA: Case studies from East Africa  

SciTech Connect

This paper reviews and compares the condition of the environmental impact assessment (EIA) system in three countries in the East Africa region: Kenya, Rwanda and Tanzania. The criteria used for the evaluation and the comparison of each system are based on the elements of the legal, administrative and procedural frameworks, as well as the context in which they operate. These criteria are adapted from the evaluation and quality control criteria derived from a number of literature sources. The study reveals that the EIA systems of Kenya and Tanzania are at a similar stage in their development. The two countries, the first to introduce the EIA concept into their jurisdiction in this part of Africa, therefore have more experience than Rwanda in the practice of environmental impact assessment, where the legislation and process requires more time to mature both from the governmental and societal perspective. The analysis of the administrative and procedural frameworks highlights the weakness in the autonomy of the competent authority, in all three countries. Finally a major finding of this study is that the contextual set up i.e. the socio-economic and political situation plays an important role in the performance of an EIA system. The context in developing countries is very different from developed countries where the EIA concept originates. Interpreting EIA conditions in countries like Kenya, Rwanda and Tanzania requires that the analysis for determining the effectiveness of their systems should be undertaken within a relevant framework, taking into account the specific requirements of those countries.

Marara, Madeleine; Okello, Nick; Kuhanwa, Zainab; Douven, Wim; Beevers, Lindsay, E-mail: l.beevers@hw.ac.uk; Leentvaar, Jan

2011-04-15

54

East African Rift System (EARS) Plume Structure: Insights from Quaternary Mafic Lavas of Turkana, Kenya  

Microsoft Academic Search

Quaternary mafic lavas from Lake Turkana (northern Kenya) provide information on processes operating beneath the East African Rift in an area of anomalous lithospheric and crustal thinning. Inferred depths of melting beneath Turkana (15---20km) are shal- lower than those recorded elsewhere along the rift, consistent with the anomalously thin crustal section. The mafic lavas have elevated incompatible trace element contents

TANYA FURMAN; JULIA G. BRYCE; JEFFREY KARSON; ANNAMARIA IOTTI

2004-01-01

55

The Precambrian crustal structure of East Africa  

NASA Astrophysics Data System (ADS)

In this thesis, the Precambrian crustal structure of East African is investigated along with the crustal structures of three Cenozoic rift basins located in the western branch of the East African Rift System (EARS). In the first part of the thesis, P-wave receiver functions are modeled using the H-k method to obtain new insights about the bulk composition and thickness of the crust for Precambrian terrains throughout East Africa. The average crustal thickness for all but one of the terrains is between 37 and 39 km. An exception is the Ubendian terrain, which has an average crustal thickness 42 km. In all terrains, the average Poisson's ratio is similar, ranging from 0.25 to 0.26, indicating a bulk crustal composition that is felsic to intermediate. The main finding of this study is that crustal structure is similar across all terrains, which span more than 4.0 Ga of earth history. There is no discernable difference in the crustal thicknesses and Poisson's ratios between the Archean and Proterozoic terrains, or between the Proterozoic terrains, unlike the variability in Precambrian crustal structure found in many other continents. In the second part of the thesis, a joint inversion of Rayleigh wave phase and group velocities and receiver functions was used to investigate the shear wave velocity structure of the crust and uppermost mantle beneath the Precambrian terrains of East Africa. In comparison with other areas of similar age in southern and western Africa where the same joint inversion method has been applied, I find that while there is little difference in the mean shear wave velocities for the entire crust across all of the Precambrian terrains, and also few differences in the thickness of the crust, there exists substantial variability in lower crustal structure. This variability is reflected primarily in the thickness of the lower crustal layers with shear wave velocities ? 4.0 km/s. This variability is found both within terrains of the same age (i.e., Archean) as well as terrains of different ages. In global studies of continental crustal structure, it is shown that high velocity (Vp ˜ 7km/s and Vs ˜4.0 km/s) lower crustal layers indicate the presence of mafic rocks, and that such layers are common in most Precambrian terrains. In contrast, my results show large variability in lower crustal structure between terrains of similar age within Africa, suggesting that making generalizations about the structure and evolution of continental crust based on global averages of the crustal velocity structure is difficult to do. The results of this study indicate that the local geological history of each terrain can lead to significant variability in crustal structure, making the use of global averages less representative of global processes than previously thought. In the third part of this thesis, forward modeling of receiver functions is used to investigate the crustal structure beneath three of the rift basins in the western branch of the East African Rift System (Lake Albert, Lake Edward and the northern part of the Lake Malawi rifts). Modeling results reveal sediment thickness of about 1 km beneath stations BUTI and KATE, located at the margins of the Lake Albert and Lake Edward rifts, respectively, and about 1.5 km beneath station KYLA in the northern part of the Lake Malawi rift. The Poisson's ratio obtained (0.4) indicate that the sediments are poorly consolidated. A thin sedimentary layer (1--1.5 km) and high Poisson's ratio is consistent with the young age (Miocene) of the rift basins. The Ps from the Moho cannot be easily identified because the first 5--6 sec of data are dominated by the Ps conversion from the sediment-bedrock interface and its reverberations. Therefore crustal thickness beneath these stations remains unknown.

Tugume, Fred Alex

56

Fisheries and Aquaculture Research Capabilities and Needs in Africa: Studies of Kenya, Malawi, Mozambique, Zimbabwe, Mauritania, Morocco, and Senegal.  

National Technical Information Service (NTIS)

The Technical Report contains the results of two missions. One mission deals with the state of fisheries and aquaculture research as well as research needs in four countries in Southeastern Africa: Kenya, Malawi, Mozambique and Zimbabwe. Following an anal...

1991-01-01

57

Somalian Earthquakes of May, 1980, East Africa  

SciTech Connect

A seismic crisis, with a m/sub b/ = 5.3 main shock, occured in the Somali Republic East Africa (10 /sup 0/N, 43 /sup 0/E) from April to November 1980. Up to 2000 earthquakes with M/sub L/>2 have been recorded during this period. This earthquake sequence is of particular interest because it occurred in a seismically inactive zone and include a rather long aftershock sequence. Two groups of epicenters were identified using a relative location procedure. Aftershocks observed during the first two weeks fall very close to the Borama City, while latter shocks are situated 10km west. This may suggest that the second group of earthquakes has been induced continental margin between the Somalian Plateau shield and the quasi-oceanic crust of the Afar-Gulf of Aden region, remains active to day and is relevant to intraplate seismicity.

Ruegg, J.C.; Lepine, J.C.; Tarantola, A.; Leveque, J.J.

1981-04-01

58

Emerging Diseases Surveillance in East Africa.  

National Technical Information Service (NTIS)

Since the inception of USAMRU-K in 1969, its activities have centered on the epidemiology, entomology and immunology of the diseases endemic to Kenya, in particular, trypanosomaisis, malaria, leishmaniasis, rift valley fever, and enteric pathogens. Clinic...

D. K. Koech

2001-01-01

59

East African mid-Holocene wet-dry transition recorded in palaeo-shorelines of Lake Turkana, northern Kenya Rift  

NASA Astrophysics Data System (ADS)

The 'wet' early to mid-Holocene of tropical Africa, with its enhanced monsoon, ended with an abrupt shift toward drier conditions and was ultimately replaced by a drier climate that has persisted until the present day. The forcing mechanisms, the timing, and the spatial extent of this major climatic transition are not well understood and remain the subject of ongoing research. We have used a detailed palaeo-shoreline record from Lake Turkana (Kenya) to decipher and characterise this marked climatic transition in East Africa. We present a high-precision survey of well-preserved palaeo-shorelines, new radiocarbon ages from shoreline deposits, and oxygen-isotope measurements on freshwater mollusk shells to elucidate the Holocene moisture history from former lake water-levels in this climatically sensitive region. In combination with previously published data our study shows that during the early Holocene the water-level in Lake Turkana was high and the lake overflowed temporarily into the White Nile drainage system. During the mid-Holocene (~ 5270 ± 300 cal. yr BP), however, the lake water-level fell by ~ 50 m, coeval with major episodes of aridity on the African continent. A comparison between palaeo-hydrological and archaeological data from the Turkana Basin suggests that the mid-Holocene climatic transition was associated with fundamental changes in prehistoric cultures, highlighting the significance of natural climate variability and associated periods of protracted drought as major environmental stress factors affecting human occupation in the East African Rift System.

Garcin, Yannick; Melnick, Daniel; Strecker, Manfred R.; Olago, Daniel; Tiercelin, Jean-Jacques

2012-05-01

60

Modelling malaria risk in East Africa at high-spatial resolution  

PubMed Central

Summary OBJECTIVES Malaria risk maps have re-emerged as an important tool for appropriately targeting the limited resources available for malaria control. In Sub-Saharan Africa empirically derived maps using standardized criteria are few and this paper considers the development of a model of malaria risk for East Africa. METHODS Statistical techniques were applied to high spatial resolution remotely sensed, human settlement and land-use data to predict the intensity of malaria transmission as defined according to the childhood parasite ratio (PR) in East Africa. Discriminant analysis was used to train environmental and human settlement predictor variables to distinguish between four classes of PR risk shown to relate to disease outcomes in the region. RESULTS Independent empirical estimates of the PR were identified from Kenya, Tanzania and Uganda (n = 330). Surrogate markers of climate recorded on-board earth orbiting satellites, population settlement, elevation and water bodies all contributed significantly to the predictive models of malaria transmission intensity in the sub-region. The accuracy of the model was increased by stratifying East Africa into two ecological zones. In addition, the inclusion of urbanization as a predictor of malaria prevalence, whilst reducing formal accuracy statistics, nevertheless improved the consistency of the predictive map with expert opinion malaria maps. The overall accuracy achieved with ecological zone and urban stratification was 62% with surrogates of precipitation and temperature being among the most discriminating predictors of the PR. CONCLUSIONS It is possible to achieve a high degree of predictive accuracy for Plasmodium falciparum parasite prevalence in East Africa using high-spatial resolution environmental data. However, discrepancies were evident from mapped outputs from the models which were largely due to poor coverage of malaria training data and the comparable spatial resolution of predictor data. These deficiencies will only be addressed by more random, intensive small areas studies of empirical estimates of PR.

Omumbo, J. A.; Hay, S. I.; Snow, R. W.; Tatem, A. J.; Rogers, D. J.

2011-01-01

61

Sediment biogeochemistry in an East African mangrove forest (Gazi Bay, Kenya)  

Microsoft Academic Search

The biogeochemistry of mangrove sediments was investigated in several mangrove forest communities in Gazi Bay, a coastal lagoon in Kenya, Africa. Carbon dioxide fluxes, sediment median grain sizes, sedimentary organic carbon, nitrogen and phosphorus contents and pore-water characteristics (ammonium, nitrate, sulfate and chloride) could be related to forest type. Mangrove sediments have pH values that range from 3.5 to 8.3

Jack J. Middelburg; Joop Nieuwenhuize; Frederik J. Slim; Boaz Ohowa

1996-01-01

62

Does the family Meesiaceae (Musci) occur in Africa?  

Microsoft Academic Search

Meesia kenyae P. Varde, a species originally described in 1955 from the altimontane elevation on Mt. Kenya in tropical East Africa, is briefly assessed taxonomically and some details of the type material are illustrated. This species is considered to be conspecific with Ceratodon purpureus (Hedw.) Brid., a weedy, cosmopolitan and highly protean species. Because M. kenyae is the only representative

Ryszard Ochyra

2001-01-01

63

Night Pass over Central Africa and the Middle East  

NASA Video Gallery

This video over Central Africa and the Middle East was taken by the crew of Expedition 29 aboard the International Space Station. This sequence of shots was taken on Oct. 1, 2011, from 21:20:24 to ...

64

Poisonous Snakes of Europe, Africa and Near East.  

National Technical Information Service (NTIS)

Topics include: Some facts about poisonous snakes; Kinds and characteristics of dangerous snakes; Precautions against snakebites; First-aid measures for snakebite; Distribution of poisonous snakes in Europe, Africa, and the Near East; Identification and h...

1969-01-01

65

Near East/North Africa Report No. 2553.  

National Technical Information Service (NTIS)

JPRS publications contain information primarily from foreign newspapers, periodicals and books, but also from news agency transmissions and broadcasts. This report Near East/North Africa Report Number 2553, contains information on interviews with Palestin...

1982-01-01

66

Sulphur and nitrogen changes in forest soils of East Africa  

Microsoft Academic Search

Summary Sulphur measurements made on soils in East Africa revealed the unexpected occurrence of sulphates in forest subsoils. Soil profiles from plantation and natural forests were analysed and a general pattern of sulphur distribution was found.

P. R. Hesse

1957-01-01

67

Near East/North Africa Report, No. 2633.  

National Technical Information Service (NTIS)

This JPRS Report number 2633, Near East/North Africa contains articles from Foreign newspapers covering topics such as: PLO's Control Over Economy of South Lebanon Analyzed, Japanese Aid, Trade Relations Flourish, Plan to Revamp Public Utilities Revealed,...

1982-01-01

68

Dust Over East Africa and Israel  

NASA Technical Reports Server (NTRS)

This scene shows a large cloud of dust blowing from northeastern Africa across Egypt, the Sinai Peninsula, over Israel and into the Middle East region on March 19, 2002. It is actually a composite image from two data sources. The true-color image of the surface was made using Moderate-resolution Imaging Spectroradiometer (MODIS) data. A false-color representation of Total Ozone Mapping Spectrometer (TOMS) measurements of aerosol index was overlain to show the extent of the dust cloud. The aerosol index is a measure of how much ultraviolet light is absorbed by the aerosol particles within the atmosphere, and is approximately equal to the optical depth. Red areas indicate high aerosol index values and correspond to the most dense portions of the dust cloud. Yellows and greens are moderately high values. The TOMS reflectivity data shows that there were relatively few clouds in the area that day. While TOMS cannot see through clouds, the aerosol index value for clouds is zero, so that any small clouds in the region would be ignored, while still detecting the aerosols between and above the clouds.

2002-01-01

69

Clinical trial of halofuginone lactate for the treatment of East Coast fever in Kenya  

Microsoft Academic Search

A field trial was undertaken to test the efficacy of halofuginone lactate in the treatment of East Coast fever under farming conditions in Kenya. The drug was administered orally at a dose of 1.2 mg\\/kg bodyweight and treatment was repeated after 48 hours. Of 293 cases treated 236 (80.5 per cent) recovered and 49 (16.7 per cent) died. Five animals

S Chema; RS Chumo; TT Dolan; JM Gathuma; AD Irvin; AD James; AS Young

1987-01-01

70

Reconstructing the origin and dispersal patterns of village chickens across East Africa: insights from autosomal markers.  

PubMed

Unravelling the genetic history of any livestock species is central to understanding the origin, development and expansion of agricultural societies and economies. Domestic village chickens are widespread in Africa. Their close association with, and reliance on, humans for long-range dispersal makes the species an important biological marker in tracking cultural and trading contacts between human societies and civilizations across time. Archaezoological and linguistic evidence suggest a complex history of arrival and dispersion of the species on the continent, with mitochondrial DNA (mtDNA) D-loop analysis revealing the presence of five distinct haplogroups in East African village chickens. It supports the importance of the region in understanding the history of the species and indirectly of human interactions. Here, through a detailed analysis of 30 autosomal microsatellite markers genotyped in 657 village chickens from four East African countries (Kenya, Uganda, Ethiopia and Sudan), we identify three distinct autosomal gene pools (I, II and III). Gene pool I is predominantly found in Ethiopia and Sudan, while II and III occur in both Kenya and Uganda. A gradient of admixture for gene pools II and III between the Kenyan coast and Uganda's hinterland (P = 0.001) is observed, while gene pool I is clearly separated from the other two. We propose that these three gene pools represent genetic signatures of separate events in the history of the continent that relate to the arrival and dispersal of village chickens and humans across the region. Our results provide new insights on the history of chicken husbandry which has been shaped by terrestrial and maritime contacts between ancient and modern civilizations in Asia and East Africa. PMID:23611649

Mwacharo, J M; Nomura, K; Hanada, H; Han, J L; Amano, T; Hanotte, O

2013-05-01

71

Reconstructing the origin and dispersal patterns of village chickens across East Africa: insights from autosomal markers  

PubMed Central

Unravelling the genetic history of any livestock species is central to understanding the origin, development and expansion of agricultural societies and economies. Domestic village chickens are widespread in Africa. Their close association with, and reliance on, humans for long-range dispersal makes the species an important biological marker in tracking cultural and trading contacts between human societies and civilizations across time. Archaezoological and linguistic evidence suggest a complex history of arrival and dispersion of the species on the continent, with mitochondrial DNA (mtDNA) D-loop analysis revealing the presence of five distinct haplogroups in East African village chickens. It supports the importance of the region in understanding the history of the species and indirectly of human interactions. Here, through a detailed analysis of 30 autosomal microsatellite markers genotyped in 657 village chickens from four East African countries (Kenya, Uganda, Ethiopia and Sudan), we identify three distinct autosomal gene pools (I, II and III). Gene pool I is predominantly found in Ethiopia and Sudan, while II and III occur in both Kenya and Uganda. A gradient of admixture for gene pools II and III between the Kenyan coast and Uganda's hinterland (P = 0.001) is observed, while gene pool I is clearly separated from the other two. We propose that these three gene pools represent genetic signatures of separate events in the history of the continent that relate to the arrival and dispersal of village chickens and humans across the region. Our results provide new insights on the history of chicken husbandry which has been shaped by terrestrial and maritime contacts between ancient and modern civilizations in Asia and East Africa.

Mwacharo, J M; Nomura, K; Hanada, H; Han, J L; Amano, T; Hanotte, O

2013-01-01

72

Evaluation of the Distribution and Impacts of Parasites, Pathogens, and Pesticides on Honey Bee (Apis mellifera) Populations in East Africa  

PubMed Central

In East Africa, honey bees (Apis mellifera) provide critical pollination services and income for small-holder farmers and rural families. While honey bee populations in North America and Europe are in decline, little is known about the status of honey bee populations in Africa. We initiated a nationwide survey encompassing 24 locations across Kenya in 2010 to evaluate the numbers and sizes of honey bee colonies, assess the presence of parasites (Varroa mites and Nosema microsporidia) and viruses, identify and quantify pesticide contaminants in hives, and assay for levels of hygienic behavior. Varroa mites were present throughout Kenya, except in the remote north. Levels of Varroa were positively correlated with elevation, suggesting that environmental factors may play a role in honey bee host-parasite interactions. Levels of Varroa were negatively correlated with levels of hygienic behavior: however, while Varroa infestation dramatically reduces honey bee colony survival in the US and Europe, in Kenya Varroa presence alone does not appear to impact colony size. Nosema apis was found at three sites along the coast and one interior site. Only a small number of pesticides at low concentrations were found. Of the seven common US/European honey bee viruses, only three were identified but, like Varroa, were absent from northern Kenya. The number of viruses present was positively correlated with Varroa levels, but was not correlated with colony size or hygienic behavior. Our results suggest that Varroa, the three viruses, and Nosema have been relatively recently introduced into Kenya, but these factors do not yet appear to be impacting Kenyan bee populations. Thus chemical control for Varroa and Nosema are not necessary for Kenyan bees at this time. This study provides baseline data for future analyses of the possible mechanisms underlying resistance to and the long-term impacts of these factors on African bee populations.

Frazier, James; Torto, Baldwyn; Baumgarten, Tracey; Kilonzo, Joseph; Kimani, James Ng'ang'a; Mumoki, Fiona; Masiga, Daniel; Tumlinson, James; Grozinger, Christina

2014-01-01

73

The Polymorphic Linker Domain of Pfmdr1 is Associated with Resistance-conferring Mutations in Plasmodium falciparum populations from East and West Africa  

Microsoft Academic Search

Sequence variation in the asparagine\\/aspartate-rich domain of pfmdr1 in 215 isolates of Plasmodium falciparum from three African countries was compared with published data. The role of this domain in modulating antimalarial sensitivity has not been established. The pfmdr1-86Y allele was significantly associated with different configurations of the Asn\\/Asp domain in West and East Africa. In Kenya, a specific form of

John Okombo; Issaka Zongo; Nahla Gadalla; Teun Bousema; Khalid Beshir; Cally Roper; Rachel Hallett; Lynette Isabella Ochola-Oyier; Colin J. Sutherland

2013-01-01

74

Summary of modeling studies of the East Olkaria geothermal field, Kenya  

SciTech Connect

A detailed three-dimensional well-by-well model of the East Olkaria geothermal field in Kenya has been developed. The model matches reasonably well the flow rate and enthalpy data from all wells, as well as the overall pressure decline in the reservoir. The model is used to predict the generating capacity of the field, well decline, enthalpy behavior, the number of make-up wells needed and the effects of injection on well performance and overall reservoir depletion. 26 refs., 10 figs.

Bodvarsson, G.S.; Pruess, K.; Stefansson, V.; Bjornsson, S.; Ojiambo, S.B.

1985-03-01

75

Genetic diversity and geographic distribution of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) genotypes associated with cassava in East Africa.  

PubMed

The genetic variability of whitefly (Bemisia tabaci) species, the vectors of cassava mosaic begomoviruses (CMBs) in cassava growing areas of Kenya, Tanzania, and Uganda, was investigated through comparison of partial sequences of the mitochondria cytochrome oxidase I (mtCOI) DNA in 2010/11. Two distinct species were obtained including sub-Saharan Africa 1 (SSA1), comprising of two sub-clades (I and II), and a South West Indian Ocean Islands (SWIO) species. Among the SSA1, sub-clade I sequences shared a similarity of 97.8-99.7% with the published Uganda 1 genotypes, and diverged by 0.3-2.2%. A pairwise comparison of SSA1 sub-clade II sequences revealed a similarity of 97.2-99.5% with reference southern Africa genotypes, and diverged by 0.5-2.8%. The SSA1 sub-clade I whiteflies were widely distributed in East Africa (EA). In comparison, the SSA1 sub-clade II whiteflies were detected for the first time in the EA region, and occurred predominantly in the coast regions of Kenya, southern and coast Tanzania. They occurred in low abundance in the Lake Victoria Basin of Tanzania and were widespread in all four regions in Uganda. The SWIO species had a sequence similarity of 97.2-97.7% with the published Reunion sequence and diverged by 2.3-2.8%. The SWIO whiteflies occurred in coast Kenya only. The sub-Saharan Africa 2 whitefly species (Ug2) that was associated with the severe CMD pandemic in Uganda was not detected in our study. PMID:23170210

Mugerwa, Habibu; Rey, Marie E C; Alicai, Titus; Ateka, Elijah; Atuncha, Hellen; Ndunguru, Joseph; Sseruwagi, Peter

2012-11-01

76

Melamine milk powder and infant formula sold in East Africa.  

PubMed

This is the first study proving the existence of melamine in milk powder and infant formula exported to the African market. A total of 49 milk powder batches were collected in Dar-es-Salaam (Tanzania, East Africa), the center of international trade in East Africa, which serves as a commercial bottleneck and shipment hub for sub-Saharan, Central, and East Africa. Two categories of samples were collected between October and December 2008, immediately after the melamine contamination of Chinese products became public: (i) market brands of all international companies supplying the East African market and (ii) illegally sold products from informal channels. Melamine concentration was determined with the AgraQuant Melamine Sensitive Assay. Despite the national import prohibition of Chinese milk products and unlabeled milk powder in Tanzania, 11% (22 of 200) of inspected microretailers sold milk powder on the local black market. Manufacturers could be identified for only 55% (27) of the 49 investigated batches. Six percent (3 of 49) of all samples and 11% (3 of 27) of all international brand name products tested revealed melamine concentrations up to 5.5 mg/kg of milk powder. This amount represents about twice the tolerable daily intake as suggested by the U.S Food and Drug Administration. Based on our study, we can assume that the number of affected children in Africa is substantial. PMID:20828481

Schoder, Dagmar

2010-09-01

77

Reducing vulnerability: the supply of health microinsurance in East Africa  

Microsoft Academic Search

Microinsurance in various forms has been available in East Africa for many generations. More recently, new efforts and formal programmes have been introduced to improve people's ability to manage their risks. Some hospitals and clinics have developed prepayment schemes. Some non-governmental organizations (NGOs) that work with low-income clients have developed risk management products like emergency credit or microinsurance products. Even

Michael J. McCord; Sylvia Osinde

2005-01-01

78

Early Iron Age Pottery Types from East Africa: Comparative Analysis  

Microsoft Academic Search

The Early Iron Age in East Africa is represented by two major related pottery types, Urewe ware (originally called Dimple-based ware) and Kwale ware, while a third collection from Lelesu in central Tanzania has clear similarities to both. This article provides a detailed typological comparison between representative collections of the three types and defines their differences and similarities, concluding that

Robert Soper

1971-01-01

79

Financial Sector Development in the Middle East and North Africa  

Microsoft Academic Search

Based on data collected on a wide range of financial sector indicators, new indices of financial development for countries in the Middle East and North Africa (MENA) are constructed, encompassing six themes: development of the monetary sector and monetary policy, banking sector development, nonbank financial development, regulation and supervision, financial openness, and institutional quality. The paper finds that the degree

Susan Creane; Rishi Goyal; A. Mushfiq Mobarak; Randa Sab

2004-01-01

80

Perspective on Grade Assignment at East Africa's State Universities.  

ERIC Educational Resources Information Center

This paper discusses approaches to grading students that are being used or could be used in state universities in East Africa. Grade assignment usually means that some kind of comparison is being made, whether with other students or established standards or based on improvement and ability. For the most part, university regulations encourage and…

Takona, J. ole

81

Reducing Pesticide Hazards to Honey Bees in Tropical East Africa  

Microsoft Academic Search

Various insecticide uses in East Africa are analysed for their actual or potential danger to honey bees. A list of commonly used chemicals is classified according to bee hazard and specific recommendations made on the protection of honey bees under tropical conditions.

M. T. Chandler

1976-01-01

82

LLNL Middle East and North Africa research database.  

National Technical Information Service (NTIS)

The Lawrence Livermore National Laboratory (LLNL) CTBT R(ampersand)D program has made significant progress assembling a comprehensive seismic database (DB) for events and derived parameters in the Middle East and North Africa (ME/NA). The LLNL research DB...

S. D. Ruppert T. F. Hauk R. Leach

1997-01-01

83

Our University: Ethnicity, Higher Education and the Quest for State Legitimacy in Kenya  

ERIC Educational Resources Information Center

In East Africa, no other country has witnessed as great a surge in university institutions as Kenya. The intent of this paper is to explore the persistence of the ethnic configurations in the surge of higher education in Kenya, within the context of the country's history. Outlining the major flashpoints in the country's history will be…

Munene, Ishmael I.

2012-01-01

84

A recent outbreak of rinderpest in East Africa  

Microsoft Academic Search

Rinderpest was brought under control in Kenya in 1976 but in April 1986 an outbreak of the disease occurred in cattle in Western Kenya, five kilometres from the Kenya - Uganda border. This was the first confirmed field outbreak of the disease in Kenya after a lull of over 10 years. Clinical disease was confined to unvaccinated zebu calves aged

J. S. Wafula; D. P. Kariuki

1987-01-01

85

Types of variation in DNA-A among isolates of East African cassava mosaic virus from Kenya, Malawi and Tanzania  

Microsoft Academic Search

Complete nucleotide sequences of the DNA-A-like molecules of three East African cassava mosaic virus (EACMV) isolates from Kenya (-K, 2801 nt) and Malawi (-MH and -MK, both 2804 nt) were determined. These sequences were compared with that published for a Tanzanian isolate (-T, 2801 nt) and the partial sequence of a third Malawian isolate. Intergenic region sequences of all isolates,

Xueping Zhou; David J. Robinson; Bryan D. Harrison

86

Protected Areas: Mixed Success in Conserving East Africa's Evergreen Forests  

PubMed Central

In East Africa, human population growth and demands for natural resources cause forest loss contributing to increased carbon emissions and reduced biodiversity. Protected Areas (PAs) are intended to conserve habitats and species. Variability in PA effectiveness and ‘leakage’ (here defined as displacement of deforestation) may lead to different trends in forest loss within, and adjacent to, existing PAs. Here, we quantify spatial variation in trends of evergreen forest coverage in East Africa between 2001 and 2009, and test for correlations with forest accessibility and environmental drivers. We investigate PA effectiveness at local, landscape and national scales, comparing rates of deforestation within park boundaries with those detected in park buffer zones and in unprotected land more generally. Background forest loss (BFL) was estimated at ?9.3% (17,167 km2), but varied between countries (range: ?0.9% to ?85.7%; note: no BFL in South Sudan). We document high variability in PA effectiveness within and between PA categories. The most successful PAs were National Parks, although only 26 out of 48 parks increased or maintained their forest area (i.e. Effective parks). Forest Reserves (Ineffective parks, i.e. parks that lose forest from within boundaries: 204 out of 337), Nature Reserves (six out of 12) and Game Parks (24 out of 26) were more likely to lose forest cover. Forest loss in buffer zones around PAs exceeded background forest loss, in some areas indicating leakage driven by Effective National Parks. Human pressure, forest accessibility, protection status, distance to fires and long-term annual rainfall were highly significant drivers of forest loss in East Africa. Some of these factors can be addressed by adjusting park management. However, addressing close links between livelihoods, natural capital and poverty remains a fundamental challenge in East Africa’s forest conservation efforts.

Pfeifer, Marion; Burgess, Neil D.; Swetnam, Ruth D.; Platts, Philip J.; Willcock, Simon; Marchant, Robert

2012-01-01

87

Ecology and control of the sand fly vectors of Leishmania donovani in East Africa, with special emphasis on Phlebotomus orientalis.  

PubMed

A literature review is provided on the state of knowledge of the ecology and control of the sand fly vectors of Leishmania donovani in East Africa, with a special emphasis on Phlebotomus orientalis. Visceral leishmaniasis caused by L. donovani is a major health problem in several areas in East Africa. Studies conducted in the past 70 years identified P. orientalis Parrot and P. martini Parrot as the principal vectors of L. donovani in Sudan, Ethiopia and Kenya and P. celiae Minter as the secondary vector of the parasite in one focus in Ethiopia. Findings on sand fly fauna and other circumstantial evidence indicate that P. martini is also responsible for transmission of L. donovani in VL endemic foci of Somalia and Uganda. Several studies showed that P. orientalis occupy distinct habitat characterized by black cotton soil and Acacia seyal-Balanites aegyptiaca vegetation, whereas P. martini and P. celiae are associated with termite mounds. Little knowledge exists on effective control measures of sand fly vectors of L. donovani in East Africa. However, recent evidence showed that use of insecticide impregnated bednets and insect repellents may reduce exposure to the bites of P. orientalis. PMID:21366778

Elnaiem, Dia-Eldin A

2011-03-01

88

Mapping Principal Preparation in Kenya and Tanzania  

ERIC Educational Resources Information Center

Purpose: The purpose of this paper is to present an overview of the principal preparation programming available to school leaders in Kenya and Tanzania. Design/methodology/approach: The authors analyzed information about the educational leadership programmes offered by a range of public and private institutions in East Africa. Data were gathered…

Onguko, Brown; Abdalla, Mohammed; Webber, Charles F.

2008-01-01

89

Epidemiology of East Coast fever (Theileria parva infection) in Kenya: past, present and the future  

PubMed Central

In this article, we review the epidemiology of East Coast fever (ECF), a tick-borne infection of cattle, in Kenya. The major factors associated with epidemiology of ECF include the agro-ecological zone (AEZ), livestock production system (LPS) and both animal breed and age. These factors appear to influence the epidemiology of ECF through structured gradients. We further show that the gradients are dynamically shaped by socio-demographic and environmental processes. For a vector-borne disease whose transmission depends on environmental characteristics that influence vector dynamics, a change in the environment implies a change in the epidemiology of the disease. The review recommends that future ECF epidemiological studies should account for these factors and the dynamic interactions between them. In Kenya, ECF control has previously relied predominantly on tick control using acaricides and chemotherapy while ECF immunization is steadily being disseminated. We highlight the contribution of ECF epidemiology and economics in the design of production system and/or geographical area-specific integrated control strategies based on both the dynamic epidemiological risk of the disease and economic impacts of control strategies. In all production systems (except marginal areas), economic analyses demonstrate that integrated control in which ECF immunization is always an important component, can play an important role in the overall control of the disease. Indeed, Kenya has recently approved ECF immunization in all production systems (except in marginal areas). If the infrastructure of the vaccine production and distribution can be heightened, large ECF endemic areas are expected to be endemically stable and the disease controlled. Finally, the review points the way for future research by identifying scenario analyses as a critical methodology on which to base future investigations on how both dynamic livestock management systems and patterns of land use influence the dynamics and complexity of ECF epidemiology and the implications for control.

2012-01-01

90

Visceral Leishmaniasis and HIV Coinfection in East Africa  

PubMed Central

Visceral Leishmaniasis (VL) is an important protozoan opportunistic disease in HIV patients in endemic areas. East Africa is second to the Indian subcontinent in the global VL caseload and first in VL-HIV coinfection rate. Because of the alteration in the disease course, the diagnostic challenges, and the poor treatment responses, VL with HIV coinfection has become a very serious challenge in East Africa today. Field experience with the use of liposomal amphotericin B in combination with miltefosine, followed by secondary prophylaxis and antiretroviral drugs, looks promising. However, this needs to be confirmed through clinical trials. Better diagnostic and follow-up methods for relapse and prediction of relapse should also be looked for. Basic research to understand the immunological interaction of the two infections may ultimately help to improve the management of the coinfection.

Diro, Ermias; Lynen, Lutgarde; Ritmeijer, Koert; Boelaert, Marleen; Hailu, Asrat; van Griensven, Johan

2014-01-01

91

The Washington File for Middle East and North Africa  

NSDL National Science Digital Library

A new email list from the US Department of State's Office of International Information Programs, the Washington File for Middle East and North Africa offers email reports about US policies in the Middle East and North Africa. Mostly transcripts, excerpts, and text statements, the materials provided should give interested users primary source knowledge of US State Department positions, unfiltered by newspapers or other media. Each report has a summary list of all enclosed topics, making browsing much quicker and easier, especially considering the amount of information that some reports provide. Two examples of issues covered by the report are: "Transcript: Rumsfeld Sees Progress Toward Afghan National Army" and "Text: U.S. Sees No Credible Evidence of Ukraine Arms Transfers to Iraq." Interested readers should note that, while never unnecessary, a lot of information is provided, meaning that it could take some time to sort through all material in each report.

92

Oil shales of Europe, North Africa, and the Near East  

SciTech Connect

Oil shale deposits are known from almost all countries in Europe and range in age from Paleozoic to Eocene. The geology of Europe is well known, and the discovery of new and significant oil shale deposits is not anticipated. A considerably different situation exists in North Africa and the Near East, where sparsely tested areas in the Sahara and desert fringe might contain important oil shale deposits. Most of the oil shale deposits in these areas (1) are of Cretaceous age, (2) occur with phosphate deposits, and (3) owe their origin to sedimentary processes associated with upwelling. Oil shales can be found from Turkey to Morocco along a paleocoastline, and better definition of this feature could result in new discoveries. In contrast to the US, oil shale deposits in Europe are being used as energy sources and will probably serve the same purpose in North Africa and the Near East.

Troger, U.

1984-04-01

93

Visceral Leishmaniasis and HIV coinfection in East Africa.  

PubMed

Visceral Leishmaniasis (VL) is an important protozoan opportunistic disease in HIV patients in endemic areas. East Africa is second to the Indian subcontinent in the global VL caseload and first in VL-HIV coinfection rate. Because of the alteration in the disease course, the diagnostic challenges, and the poor treatment responses, VL with HIV coinfection has become a very serious challenge in East Africa today. Field experience with the use of liposomal amphotericin B in combination with miltefosine, followed by secondary prophylaxis and antiretroviral drugs, looks promising. However, this needs to be confirmed through clinical trials. Better diagnostic and follow-up methods for relapse and prediction of relapse should also be looked for. Basic research to understand the immunological interaction of the two infections may ultimately help to improve the management of the coinfection. PMID:24968313

Diro, Ermias; Lynen, Lutgarde; Ritmeijer, Koert; Boelaert, Marleen; Hailu, Asrat; van Griensven, Johan

2014-06-01

94

Results of cataract surgery in young children in east Africa  

Microsoft Academic Search

BACKGROUNDCataract is the leading cause of blindness in children in east Africa. The results of surgery are poor, partly because of inadequate correction of aphakia.METHODSA retrospective survey of 118 eyes in 71 children with bilateral cataract. All eyes had implantation of an IOL at the time of cataract surgery. The average age at surgery was 3.5 years. 28 patients(39%) were

David Yorston; Mark Wood; Allen Foster

2001-01-01

95

Towards an integrated soil moisture drought monitor for East Africa  

NASA Astrophysics Data System (ADS)

East Africa contains a number of highly drought prone regions, and the humanitarian consequences of drought in those regions can be severe. The severity of these drought impacts combined with a paucity of in situ monitoring networks has given rise to numerous efforts to develop reliable remote drought monitoring systems based on satellite data, physically-based models, or a combination of the two. Here we present the results of a cross-comparison and preliminary integration of three soil moisture monitoring methodologies that, combined, offer the potential for a soil moisture based drought monitoring system that is robust across the diverse climatic and ecological zones of East Africa. Three independent methods for estimating soil moisture anomalies, the AMSR-E microwave based satellite sensor, the ALEXI thermal infrared based model and the Noah land surface model, are evaluated using triple collocation error analysis (TCEA). TCEA is used to estimate the reliability of each soil moisture anomaly methodology through statistical cross-comparison-a particularly useful approach given the virtual absence of in situ soil moisture data in this region. While AMSR-E, ALEXI, and Noah each appear to produce reliable soil moisture anomaly estimates over some areas within East Africa, many areas posed significant challenges to one or more methods. These challenges include seasonal cloud cover that hinders ALEXI estimates, dense vegetation that impedes AMSR-E retrievals, and complex hydrology that tests the limits of Noah model assumptions. TCEA allows for assessment of the reliability of each method across seasonal and geographic gradients and provides systematic criteria for merging the three methods into an integrated estimate of spatially distributed soil moisture anomalies for all of East Africa. Results for the period 2007-2011 demonstrate the potential and the limitations of this approach in application to real time drought monitoring.

Anderson, W. B.; Hain, C.; Zaitchik, B. F.; Anderson, M. C.; Alo, C. A.; Yilmaz, M. T.

2011-12-01

96

The atmospheric deposition of phosphorus in Lake Victoria (East Africa)  

Microsoft Academic Search

Wet and dry atmospheric fluxes of total phosphorus (TP) and soluble reactive phosphorus (SRP) measured at four sites over a 12-month period were used to estimate lake-wide atmospheric phosphorus (P) deposition to Lake Victoria, East Africa. Atmospheric samples were collected in plastic buckets with top diameter of 25.5 cm by 30 cm deep. The highest P loading rates of 2.7 (TP) and

Rashid A. Tamatamah; Robert E. Hecky; Hamish C. Duthie

2005-01-01

97

Coronary artery disease in Africa and the Middle East  

PubMed Central

Countries in Africa and the Middle East bear a heavy burden from cardiovascular disease. The prevalence of coronary heart disease is promoted in turn by a high prevalence of cardiovascular risk factors, particularly smoking, hypertension, dyslipidemia, diabetes, and sedentary lifestyles. Patients in Africa and the Middle East present with myocardial infarction at a younger age, on average, compared with patients elsewhere. The projected future burden of mortality from coronary heart disease in Africa and the Middle East is set to outstrip that observed in other geographical regions. Recent detailed nationally representative epidemiological data are lacking for many countries, and high proportions of transient expatriate workers in countries such as Saudi Arabia and the United Arab Emirates complicate the construction of such datasets. However, the development of national registries in some countries is beginning to reveal the nature of coronary heart disease. Improving lifestyles (reducing calorie intake and increasing physical activity) in patients in the region will be essential, although cultural and environmental barriers will render this difficult. Appropriate prescribing of pharmacologic treatments is essential in the prevention and management of cardiovascular disease. In particular, recent controversies relating to the therapeutic profile of beta-blockers may have reduced their use. The current evidence base suggests that beta-blockers are as effective as other therapies in preventing cardiovascular disease and that concerns relating to their use in hypertension and cardiovascular disease have been overstated.

Almahmeed, Wael; Arnaout, Mohamad Samir; Chettaoui, Rafik; Ibrahim, Mohsen; Kurdi, Mohamed Ibrahim; Taher, Mohamed Awad; Mancia, Giuseppe

2012-01-01

98

Coronary artery disease in Africa and the Middle East.  

PubMed

Countries in Africa and the Middle East bear a heavy burden from cardiovascular disease. The prevalence of coronary heart disease is promoted in turn by a high prevalence of cardiovascular risk factors, particularly smoking, hypertension, dyslipidemia, diabetes, and sedentary lifestyles. Patients in Africa and the Middle East present with myocardial infarction at a younger age, on average, compared with patients elsewhere. The projected future burden of mortality from coronary heart disease in Africa and the Middle East is set to outstrip that observed in other geographical regions. Recent detailed nationally representative epidemiological data are lacking for many countries, and high proportions of transient expatriate workers in countries such as Saudi Arabia and the United Arab Emirates complicate the construction of such datasets. However, the development of national registries in some countries is beginning to reveal the nature of coronary heart disease. Improving lifestyles (reducing calorie intake and increasing physical activity) in patients in the region will be essential, although cultural and environmental barriers will render this difficult. Appropriate prescribing of pharmacologic treatments is essential in the prevention and management of cardiovascular disease. In particular, recent controversies relating to the therapeutic profile of beta-blockers may have reduced their use. The current evidence base suggests that beta-blockers are as effective as other therapies in preventing cardiovascular disease and that concerns relating to their use in hypertension and cardiovascular disease have been overstated. PMID:22368447

Almahmeed, Wael; Arnaout, Mohamad Samir; Chettaoui, Rafik; Ibrahim, Mohsen; Kurdi, Mohamed Ibrahim; Taher, Mohamed Awad; Mancia, Giuseppe

2012-01-01

99

Regional stratigraphy and petroleum geology, North Africa-Middle East  

SciTech Connect

The North Africa-Middle East petroleum provinces are part of the broad sedimentary platform that occupied the northern and northeastern borders of the African-Arabian craton adjacent to the ancestral Hercynian (late Paleozoic) and subsequent Tethyan-Alpine oceans. Carbonate-clastic-evaporite sediments of infra-Cambrian through Holocene age were cyclically deposited in a relatively continuous belt around the eastern and northern borders of the craton, mainly on a broad, shallow-water platform adjacent to the proto-Tethys and Tethys seaway. The Paleozoic section reaches a substantial thickness in the subsurface of the Middle East and in northern Africa adjacent to the Mediterranean Sea, but all or part of it is absent because of nondeposition or erosion over much of the region. Post-Paleozoic deposition was more or less continuous across the entire craton border region in the Middle East and along the northern border of the Sahara platform in North Africa and in Somalia and eastern Ethiopia. Similar marine and associated sedimentary rock facies are present in all of these regions, although paleotectonic-stratigraphic interrelationships and continental paleolatitude positions have greatly affected petroleum generation and accumulation in the specific provinces along the craton border. A series of regional stratigraphic-sedimentary environment, and continental position, layer maps illustrates the relative influence of these factors through geologic time with respect to the relationship between petroleum reservoirs, source rocks, and confining rock facies.

Peterson, J.A. (Univ. of Montana, Missoula (United States))

1991-03-01

100

Fission-track dating of pumice from the KBS Tuff, East Rudolf, Kenya  

USGS Publications Warehouse

Fission-track dating of zircon separated from two pumice samples from the KBS Tuff in the Koobi Fora Formation, in Area 131, East Rudolf, Kenya, gives an age of 2.44??0.08 Myr for the eruption of the pumice. This result is compatible with the previously published K-Ar and 40Ar/ 39Ar age spectrum estimate of 2.61??0.26 Myr for the KBS Tuff in Area 105, but differs from the more recently published K-Ar date of 1.82??0.04 Myr for the KBS Tuff in Area 131. This study does not support the suggestion that pumice cobbles of different ages occur in the KBS Tuff. ?? 1976 Nature Publishing Group.

Hurford, A. J.; Gleadow, A. J. W.; Naeser, C. W.

1976-01-01

101

East Africa Subregion: Enhancing Transportation Management to Foster U.S. Agricultural Trade Opportunities.  

National Technical Information Service (NTIS)

In September 1999, USAID/Africa Bureau's Africa Trade and Investment Policy (ATRIP) Program provided USDA/Foreign Agricultural Service/International Cooperation and Development with funding to conduct a series of interrelated activities for the East Afric...

H. Reichert J. Caron

2001-01-01

102

International energy outlook. Volume 1. Mideast, Far East, and Africa  

SciTech Connect

The developing nations of the Mideast, Far East, and Africa face a bleaker - and more-complicated - energy picture than that of the West. Rapid industrial and agricultural expansion in the region severely drains already-inadequate energy systems. Energy-importing countries find they must diversify and develop indigenous resources, but often lack the technical known-how to do so. Volume 1 is a compilation of official US government intelligence reports examining the way 22 countries in the Mideast, Far East, and Africa are responding to the energy problems. The countries covered are: Algeria, Australia, Burma, China, Egypt, Gabon, India, Indonesia, Ivory Coast, Japan, Korea, Kuwait, Lebanon, Morocco, Mozambique, Pakistan, Saudi Arabia, South Africa, Sudan, Taiwan, Tunisia and Turkey. The range and detail of country reports vary, due to availability of reports. Although the book details current energy situations, its main emphasis is on the future, including estimates of future production and consumption, and descriptions of energy development plans. Some of the countries in this region are fortunate to have petrochemical resources, while electric energy expansion is crucial to national development in all. Coal will be filling the gap left by diminishing oil supplies. 61 tables.

Jablonski, D.M. (ed.)

1982-01-01

103

Agricultural Research in the Private Sector in Africa: The Case of Kenya.  

National Technical Information Service (NTIS)

The private sector's role, impact, and prospects in agricultural research (AR) in Kenya are described in the report, which identifies six types of private entities that conduct AR in Kenya and presents examples of their research activities: (1) multinatio...

S. H. Hobbs T. A. Taylor

1987-01-01

104

Long-acting oxytetracycline prophylaxis to protect susceptible cattle introduced into an area of Kenya with endemic East Coast fever  

Microsoft Academic Search

Two field trials were carried out in successive years at the Ngong Veterinary Farm, Kenya, in which young cattle, previously unexposed to tick-borne diseases, were introduced into an area with endemic East Coast fever while protected by a series of injections of a long-acting oxytetracycline. In 1984, 12 animals which received injections of 20 mg\\/kg of the drug on days

RS Chumo; AD Irvin; SP Morzaria; J Katende; RE Purnell

1989-01-01

105

Recent work on the production and utilization of tree fodder in East Africa  

Microsoft Academic Search

Most of the work discussed in the paper is part of the Agroforestry Research Network for Africa (AFRENA). In the sub-humid highlands the most common form of livestock management is a mixture of grazing, tethering and stall feeding. In the arid and semi-arid lowlands of Kenya the normal livestock management practice is grazing. Leucaena leucocephala was a popular fodder species

R. L. Roothaert; R. T. Paterson

1997-01-01

106

Country Profile: Middle East, and North Africa (MENA)  

NSDL National Science Digital Library

The International Finance Corporation (reviewed in the November 11, 1997 Scout Report for Business & Economics) established the Middle East, and North Africa Department (MENA) to support research and investment projects in seventeen Central Asian, Middle Eastern, and North African nations. Socioeconomic data from these efforts are summarized in narrative and numerical form in the MENA Country Profiles. These overviews give background social information, key economic ratios, and long-term trends. Annotated links to relevant data from other IFC databases, the US State Department, and the Central Intelligence Agency point users to more information.

1998-01-01

107

The polymorphic linker domain of pfmdr1 is associated with resistance-conferring mutations in Plasmodium falciparum populations from East and West Africa.  

PubMed

Sequence variation in the asparagine/aspartate-rich domain of pfmdr1 in 215 isolates of Plasmodium falciparum from three African countries was compared with published data. The role of this domain in modulating antimalarial sensitivity has not been established. The pfmdr1 86Y allele was significantly associated with different configurations of the Asn/Asp-rich domain in West and East Africa. In Kenya, a specific form of the Asn/Asp-rich domain was significantly linked to the 86Y, 184Y, and 1246Y haplotype of pfmdr1. PMID:23836177

Okombo, John; Zongo, Issaka; Gadalla, Nahla; Bousema, Teun; Beshir, Khalid B; Roper, Cally; Hallett, Rachel; Ochola-Oyier, Lynette Isabella; Sutherland, Colin J

2013-09-01

108

Off-axis volcanism in the Gregory rift, east Africa: implications for models of continental rifting  

SciTech Connect

The largest volcanic centers of the Gregory rift occur in two belts located 100 to 150 km east and west of the axis of the rift valley. These off-axis volcanic belts include the highest peaks on the continent of Africa and are interpreted to lie above the intersection of low-angle detachment systems with the base of a regionally thinned lithosphere. These detachment systems are manifested at the surface as a series of breakaway zones and regional bounding faults that produce subbasins with half-graben form. The asymmetry of subbasins alternates along the rift axis, indicating that the polarity of the underlying active detachment systems also reverses. The detachments are separated laterally by regional oblique-slip accommodation zones typified by wrench-style tectonism. Off-axis from the rift, the detachments are inferred to merge along strike as they cut to the base of the lithosphere. This results in irregular but persistent paired zones of volcanism and lithospheric thinning off-axis from the rift proper. The development of major volcanic cones such as Mount Kilimanjaro may be controlled by the interaction of leaky accommodation zones with the regions of structurally thinned lithosphere. The central Kenya hot spot has produced the anomalous quantities of volcanic material that fills the Gregory rift and probably enhances the off-axis volcanism but does not directly control its location. The model proposed here for tectonic controls of volcanism in the Gregory rift may be applicable to Phanerozoic continental rifts in general.

Bosworth, W.

1987-05-01

109

The use of Toddalia asiatica (L) Lam. (Rutaceae) in traditional medicine practice in East Africa.  

PubMed

Toddalia asiatica (L) Lam. (Rutaceae) has been used by traditional health practitioners in East Africa for management of diseases, however, the extent of its usefulness has not been established to date. Fieldwork for this study was carried out in the Lake Victoria Basin between March and September 2006. The purpose was to collect ethnomedical information that will serve as a basis for further studies to establish current and potential medicinal uses. The ethnomedical information was obtained through interviews using semi-structured questionnaires. Consultative meetings were also conducted with traditional health practitioners and other members of the communities in Kenya, Uganda and Tanzania. Results of this study show that Toddalia asiatica is collected in the wild, prepared mostly as decoctions or concoctions and administered orally. It is used for the management of a number of disease conditions. The most frequently cited diseases were stomach problems (78%) followed by malaria (25%). Cough (22%), chest pain (13%), food poisoning (8%), sore throat (7%), were also mentioned among other disease conditions treated. Validation studies of therapeutic claims will be carried out at a later date. PMID:17996412

Orwa, J A; Jondiko, I J O; Minja, R J A; Bekunda, M

2008-01-17

110

Evaluating Downscaling Methods for Seasonal Climate Forecasts over East Africa  

NASA Astrophysics Data System (ADS)

The U.S. National Multi-Model Ensemble seasonal forecasting system is providing hindcast and real-time data streams to be used in assessing and improving seasonal predictive capacity. 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 NMME forecasts specifically for use in impact modeling within hub regions including East Africa, the Hindu Kush-Himalayan (HKH) region and Mesoamerica. One of the participating models in NMME is the NASA Goddard Earth Observing System (GEOS5). This work will present an intercomparison of downscaling methods using the GEOS5 seasonal forecasts of temperature and precipitation over East Africa. The current seasonal forecasting system provides monthly averaged forecast anomalies. These anomalies must be spatially downscaled and temporally disaggregated for use in application modeling (e.g. hydrology, agriculture). There are several available downscaling methodologies that can be implemented to accomplish this goal. Selected methods include both a non-homogenous hidden Markov model and an analogue based approach. A particular emphasis will be placed on quantifying the ability of different methods to capture the intermittency of precipitation within both the short and long rain seasons. Further, the ability to capture spatial covariances will be assessed. Both probabilistic and deterministic skill measures will be evaluated over the hindcast period.

Roberts, J. B.; Robertson, F. R.; Bosilovich, M. G.; Lyon, B.

2013-12-01

111

Mineral facilities of Africa and the Middle East  

USGS Publications Warehouse

This map displays over 1,500 mineral facilities in Africa and the Middle East. The mineral facilities include mines, plants, mills, or refineries of aluminum, cement, coal, copper, diamond, gold, iron and steel, nickel, platinum-group metals, salt, and silver, among others. The data used in this poster were compiled from multiple sources, including the 2004 USGS Minerals Yearbook (Africa and Middle East volume), Minerals Statistics and Information from the USGS Web site (http://minerals.usgs.gov/minerals/), and data collected by USGS minerals information country specialists. Data reflect the most recent published table of industry structure for each country. Other sources include statistical publications of individual countries, annual reports and press releases of operating companies, and trade journals. Due to the sensitivity of some energy commodity data, the quality of these data should be evaluated on a country-by-country basis. Additional information and explanation is available from the country specialists. See Table 1 for general information about each mineral facility site including country, location and facility name, facility type, latitude, longitude, mineral commodity, mining method, main operating company, status, capacity, and units.

Eros, J.M.; Candelario-Quintana, Luissette

2006-01-01

112

Evaluating Downscaling Methods for Seasonal Climate Forecasts over East Africa  

NASA Technical Reports Server (NTRS)

The U.S. National Multi-Model Ensemble seasonal forecasting system is providing hindcast and real-time data streams to be used in assessing and improving seasonal predictive capacity. 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 NMME forecasts specifically for use in impact modeling within hub regions including East Africa, the Hindu Kush-Himalayan (HKH) region and Mesoamerica. One of the participating models in NMME is the NASA Goddard Earth Observing System (GEOS5). This work will present an intercomparison of downscaling methods using the GEOS5 seasonal forecasts of temperature and precipitation over East Africa. The current seasonal forecasting system provides monthly averaged forecast anomalies. These anomalies must be spatially downscaled and temporally disaggregated for use in application modeling (e.g. hydrology, agriculture). There are several available downscaling methodologies that can be implemented to accomplish this goal. Selected methods include both a non-homogenous hidden Markov model and an analogue based approach. A particular emphasis will be placed on quantifying the ability of different methods to capture the intermittency of precipitation within both the short and long rain seasons. Further, the ability to capture spatial covariances will be assessed. Both probabilistic and deterministic skill measures will be evaluated over the hindcast period.

Robertson, Franklin R.; Roberts, J. Brent; Bosilovich, Michael; Lyon, Bradfield

2013-01-01

113

Evaluating Downscaling Methods for Seasonal Climate Forecasts over East Africa  

NASA Technical Reports Server (NTRS)

The U.S. National Multi-Model Ensemble seasonal forecasting system is providing hindcast and real-time data streams to be used in assessing and improving seasonal predictive capacity. 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 NMME forecasts specifically for use in impact modeling within hub regions including East Africa, the Hindu Kush-Himalayan (HKH) region and Mesoamerica. One of the participating models in NMME is the NASA Goddard Earth Observing System (GEOS5). This work will present an intercomparison of downscaling methods using the GEOS5 seasonal forecasts of temperature and precipitation over East Africa. The current seasonal forecasting system provides monthly averaged forecast anomalies. These anomalies must be spatially downscaled and temporally disaggregated for use in application modeling (e.g. hydrology, agriculture). There are several available downscaling methodologies that can be implemented to accomplish this goal. Selected methods include both a non-homogenous hidden Markov model and an analogue based approach. A particular emphasis will be placed on quantifying the ability of different methods to capture the intermittency of precipitation within both the short and long rain seasons. Further, the ability to capture spatial covariances will be assessed. Both probabilistic and deterministic skill measures will be evaluated over the hindcast period

Roberts, J. Brent; Robertson, Franklin R.; Bosilovich, Michael; Lyon, Bradfield; Funk, Chris

2013-01-01

114

Present situation of echinococcosis in the Middle East and Arabic North Africa  

Microsoft Academic Search

Echinococcosis is one of the major zoonotic parasitic diseases in the Middle East and Arabic North Africa from Morocco to Egypt. Both cystic and alveolar echinococcosis has been reported from these areas. However, cystic echinococcosis is more prevalent and has been reported from all countries in the Middle East and Arabic North Africa. Alveolar echinococcosis is less prevalent and has

Seyed Mahmoud Sadjjadi

2006-01-01

115

Crustal model for the Middle East and North Africa region: implications for the isostatic compensation mechanism  

Microsoft Academic Search

We present a new 3-D crustal model for the Middle East and North Africa region that includes detailed topography, sediment thickness, and Moho depth values. The model is obtained by collecting, integrating, and interpolating reliable, published sedimentary rock thickness and Moho depth measurements in the Middle East and North Africa region. To evaluate the accuracy of the model, the 3-D

Dogan Seber; Eric Sandvol; Christine Sandvol; Carrie Brindisi; Muawia Barazangi

2001-01-01

116

Early Permian to Middle Jurassic rifting and sedimentation in East Africa and Madagascar  

NASA Astrophysics Data System (ADS)

Pre-drift sediments of Madagascar (Early Permian-Middle Jurassic) have been studied palynologically. These studies resulted in a more precise dating of individual stratigraphic units and the recognition of minor and major breaks in the succession. Palynostratigraphic and physical evidence of unconformities have been used to subdivide the pre-drift sediments into depositional cycles and to infer rifting events. A comparison with equivalent strata of Mozambique, Tanzania, Kenya, Ethiopia and Somalia shows a general correspondence and provides additional information for the construction of a generalized framework for the East African/Madagascan region which demonstrates the relationships between rifting and sedimentation and elucidates the prehistory of the break-up of Gondwana into a western and eastern fragment during the Middle Jurassic. The predrift succession of East Africa/Madagascar can be subdivided into two major sequences, a Karoo sequence (cycles 1 5, Asselian-early Smithian) and a transitional sequence (cycles 6 9, Ladinian-early Bajocian). The two sequences are separeted by a late Scythian to Anisian hiatus which indicates extensive uplift and erosion before a major rifting event initiated the resumption of sedimentation in the Ladinian. This Middle Triassic event marks the transition from the intracratonic rift stage to the pericratonic basin stage and correlates with a significant event in the Pangaean history, the transition from final coalescence to initial dispersal. The onset of the southward drift of Madagascar is believed to have occurred about 60 Ma later near the Aalenian-Bajocian boundary, contemporaneous with or immediately after the deposition of syntectonic sediments of cycle 9.

Hankel, O.

1994-12-01

117

The Earliest Hominid Migration out of Africa and Near East Colonization  

Microsoft Academic Search

It is generally accepted that Central East Africa was the springboard for hominid evolution in the latest Miocene or Early Pliocene. However the timing and pathways of migrations from Africa to Eurasia are still debatable. The only certain land bridge and main route between Africa and Eurasia since the Late Pliocene-Early Pleistocene is the Levantine Corridor. This is evident in

H. Ron; S. Levi; N. Porat

2001-01-01

118

Molecular biodiversity of cassava begomoviruses in Tanzania: evolution of cassava geminiviruses in Africa and evidence for East Africa being a center of diversity of cassava geminiviruses  

PubMed Central

Cassava is infected by numerous geminiviruses in Africa and India that cause devastating losses to poor farmers. We here describe the molecular diversity of seven representative cassava mosaic geminiviruses (CMGs) infecting cassava from multiple locations in Tanzania. We report for the first time the presence of two isolates in East Africa: (EACMCV-[TZ1] and EACMCV-[TZ7]) of the species East African cassava mosaic Cameroon virus, originally described in West Africa. The complete nucleotide sequence of EACMCV-[TZ1] DNA-A and DNA-B components shared a high overall sequence identity to EACMCV-[CM] components (92% and 84%). The EACMCV-[TZ1] and -[TZ7] genomic components have recombinations in the same genome regions reported in EACMCV-[CM], but they also have additional recombinations in both components. Evidence from sequence analysis suggests that the two strains have the same ancient origin and are not recent introductions. EACMCV-[TZ1] occurred widely in the southern part of the country. Four other CMG isolates were identified: two were close to the EACMV-Kenya strain (named EACMV-[KE/TZT] and EACMV-[KE/TZM] with 96% sequence identity); one isolate, TZ10, had 98% homology to EACMV-UG2Svr and was named EACMV-UG2 [TZ10]; and finally one isolate was 95% identical to EACMV-[TZ] and named EACMV-[TZ/YV]. One isolate of African cassava mosaic virus with 97% sequence identity with other isolates of ACMV was named ACMV-[TZ]. It represents the first ACMV isolate from Tanzania to be sequenced. The molecular variability of CMGs was also evaluated using partial B component nucleotide sequences of 13 EACMV isolates from Tanzania. Using the sequences of all CMGs currently available, we have shown the presence of a number of putative recombination fragments that are more prominent in all components of EACMV than in ACMV. This new knowledge about the molecular CMG diversity in East Africa, and in Tanzania in particular, has led us to hypothesize about the probable importance of this part of Africa as a source of diversity and evolutionary change both during the early stages of the relationship between CMGs and cassava and in more recent times. The existence of multiple CMG isolates with high DNA genome diversity in Tanzania and the molecular forces behind this diversity pose a threat to cassava production throughout the African continent.

Ndunguru, J; Legg, JP; Aveling, TAS; Thompson, G; Fauquet, CM

2005-01-01

119

Identification of a target population for immunisation against East Coast fever in coastal Kenya.  

PubMed

Two experiments were carried out to identify the target population of cattle for immunisation against East Coast fever (ECF) using the infection-and-treatment method. Firstly, a sentinel-calf study was used to determine the age window for ECF immunisation by determining ages at clinical detection of infection with Theileria parva. Six groups of five naive cross-bred (Bos taurus/Bos indicus) male calves, introduced at intervals of 2 months at a mean age of 26 days, were exposed to natural tick challenge on a high ECF-risk, small-holder farm in the coastal lowland, coconut-cassava agro-ecological zone of coastal Kenya. Secondly, a challenge study evaluated the relationship between the presence of T. parva antibodies and immunity. Ten indigenous adult Zebu cattle and nine Zebu young stock purchased from farmers in the same zone, and eight cross-bred calves (survivors of the sentinel-calf study) were challenged with 10 times the immunising dose of T. parva Marikebuni stock. Twenty-four of these 27 cattle had high antibody titres before challenge. Two cross-bred calves, obtained from an ECF-free area and seronegative to T. parva schizont antigen, also were challenged and used as susceptible controls. Twenty-five (83%) of the 30 sentinel calves contracted ECF over an age range of 36-116 days (mean 72 days). The remaining five calves died of other causes within 2 months of arrival on the farm. Fourteen of the 25 calves survived the infection and developed antibodies to T. parva. Despite tick control, seven of these 14 calves had a second episode of ECF and two died. In total, 13 of the 25 calves that contracted ECF died. Only one of 19 indigenous Zebu animals developed clinical ECF when challenged with T. parva Marikebuni (mild clinical signs with spontaneous recovery). Of the eight cross-bred survivors from the first experiment, only one succumbed to ECF when challenged and it died. Both susceptible cross-bred calves developed severe clinical signs of ECF and one died. The experimental studies show that in the high ECF-risk areas of the coconut-cassava zone of coastal Kenya, immunisation against ECF in cross-bred (B. taurus/B. indicus) cattle should be targeted at an early age (preferably within 1-2 months of birth). PMID:11566376

Maloo, S H; Ngumi, P; Mbogo, S; Williamson, S; Thorpe, W; Rowlands, G J; Perry, B D

2001-11-01

120

Echinococcus Infections in Man and Animals in Kenya  

Microsoft Academic Search

1. Hydatid cysts are found in more than 30 per cent of all cattle, sheep and goats in Kenya, but the disease is prevalent in man only in the semi-desert area of Turkana. Up to the time of the present investigation the life-cycle of the parasite in East Africa had not been studied, but it was suggested that wild carnivores,

George S. Nelson; Robert L. Rausch

1963-01-01

121

Aerial Collection of Culicoides schultzei Group (Diptera: Ceratopogonidae) in Kenya.  

National Technical Information Service (NTIS)

The feeding patterns and abundance of species of the Culicoides schultzei group strongly suggest that they are vectors of bluetongue and ephemeral fever viruses in Kenya. The spread of bluetongue and ephemeral fever viruses in East Africa is thought to be...

F. G. Davies K. J. Linthicum

1984-01-01

122

Remote sensing of geobotanical trends in East Africa  

NASA Technical Reports Server (NTRS)

The spatial and phenological distribution of vegetation was examined in a remote sensing geobotanical study of the East Africa Rift region. Six normalized difference vegetation index (NDVI) AVHRR (advanced very high resolution radiometer) scenes (February, June, and September of both 1984 and 1987) were used as a measure of vegetation presence. NOAA ETOPO-5 elevation and geographic coordinate data were coregistered with the multitemporal NDVI images. Univariate and multivariate statistics indicate that the NDVI values are significantly associated with elevation, latitude, and longitude. This supports the concept of quantifiable, regional gradients that affect large-scale geobotanical studies. A quadratic regression line was fitted to the NDVI, elevation, latitude, and longitudinal data. In this way a regional trend, as affected by elevation, was determined. The deviation of the actual data from this regional trend was displayed as an image, and shows the local climatic and geological influences.

Warner, Timothy A.; Evans, Carla S.; Heirtzler, James R.

1989-01-01

123

DROUGHT-ASSOCIATED CHIKUNGUNYA EMERGENCE ALONG COASTAL EAST AFRICA  

Microsoft Academic Search

Epidemics of chikungunya fever, an Aedes spp.-borne viral disease, affected hundreds of thousands of people in western Indian Ocean islands and India during 2005-2006. The initial outbreaks occurred in coastal Kenya (Lamu, then Mombasa) in 2004. We investigated eco-climatic conditions associated with chikungunya fever emergence along coastal Kenya using epidemiologic investigations and satellite data. Unusually dry, warm conditions preceded the

JEAN-PAUL CHRETIEN; ASSAF ANYAMBA; SHERYL A. BEDNO; ROBERT F. BREIMAN; ROSEMARY SANG; KIBET SERGON; ANN M. POWERS; CLAYTON O. ONYANGO; JENNIFER SMALL; COMPTON J. TUCKER; KENNETH J. LINTHICUM

2007-01-01

124

Design and descriptive epidemiology of the Infectious Diseases of East African Livestock (IDEAL) project, a longitudinal calf cohort study in western Kenya  

PubMed Central

Background There is a widely recognised lack of baseline epidemiological data on the dynamics and impacts of infectious cattle diseases in east Africa. The Infectious Diseases of East African Livestock (IDEAL) project is an epidemiological study of cattle health in western Kenya with the aim of providing baseline epidemiological data, investigating the impact of different infections on key responses such as growth, mortality and morbidity, the additive and/or multiplicative effects of co-infections, and the influence of management and genetic factors. A longitudinal cohort study of newborn calves was conducted in western Kenya between 2007-2009. Calves were randomly selected from all those reported in a 2 stage clustered sampling strategy. Calves were recruited between 3 and 7 days old. A team of veterinarians and animal health assistants carried out 5-weekly, clinical and postmortem visits. Blood and tissue samples were collected in association with all visits and screened using a range of laboratory based diagnostic methods for over 100 different pathogens or infectious exposures. Results The study followed the 548 calves over the first 51 weeks of life or until death and when they were reported clinically ill. The cohort experienced a high all cause mortality rate of 16% with at least 13% of these due to infectious diseases. Only 307 (6%) of routine visits were classified as clinical episodes, with a further 216 reported by farmers. 54% of calves reached one year without a reported clinical episode. Mortality was mainly to east coast fever, haemonchosis, and heartwater. Over 50 pathogens were detected in this population with exposure to a further 6 viruses and bacteria. Conclusion The IDEAL study has demonstrated that it is possible to mount population based longitudinal animal studies. The results quantify for the first time in an animal population the high diversity of pathogens a population may have to deal with and the levels of co-infections with key pathogens such as Theileria parva. This study highlights the need to develop new systems based approaches to study pathogens in their natural settings to understand the impacts of co-infections on clinical outcomes and to develop new evidence based interventions that are relevant.

2013-01-01

125

Sexual and treatment-seeking behaviour for sexually transmitted infection in long-distance transport workers of East Africa  

PubMed Central

Objective To investigate the sexual and treatment?seeking behaviour for sexually transmitted infection (STI) in long?distance transport workers of East Africa. Methods A health?seeking behaviour survey was carried out at four sites on the Mombasa–Kampala trans?Africa highway (n?=?381). The questionnaires probed details of STI knowledge, symptoms and care?seeking behaviour. In one site at the Kenya–Uganda border, a sexual patterning matrix was used (n?=?202) to measure sexual behaviour in truck drivers and their assistants over the 12?month period before the interview. Results Over half of the sexual acts of long?distance transport workers over 12?months were with female sex workers, with an annual average of 2.8 sexual partners. Condom use was reported at 70% for liaisons with casual partners. 15% of truckers had had a self?reported STI and one?third exhibited high?risk sexual behaviour in the previous year. Of those with an STI, 85% had symptoms when on the road and 77.2% sought treatment within 1?week of onset of symptoms. 94% of drivers and 56% of assistants sought treatment for STI in a private health facility or pharmacy. The cost of private facilities and pharmacies was not significantly higher than in the public sector. Waiting times were three times longer in the public sector. Only 28.9% of patients completed their medication courses as prescribed. Conclusions Truck drivers and their assistants in East Africa have high rates of reported STIs and many continue to exhibit high?risk sexual behaviour. The transport workers studied here favoured private health facilities because of convenience and shorter waiting times.

Morris, Chester N; Ferguson, Alan G

2007-01-01

126

Molecular detection and genetic characterization of kobuviruses and astroviruses in asymptomatic local pigs in East Africa.  

PubMed

In this study, swine fecal specimens (n = 251) collected from nursing and weaned piglets raised under smallholder production systems were screened for the presence of kobuviruses by RT-PCR. Porcine kobuviruses were detected in 13.1 % (33/251) of the samples. We demonstrated that porcine kobuvirus infections exist in indigenous pigs in Kenya and Uganda and that the prevalence was higher in young piglets than older pigs: nursing piglets (15 %), post-weaning (3-month-old) pigs (17 %), 4-month-old pigs (10 %). Genetic analysis of the partial RNA-dependent RNA polymerase (RdRp) region (690 nt) revealed that kobuviruses circulating in East Africa are diverse, sharing nucleotide sequence identities ranging from 89.7 to 99.1 % and 88 to 92.3 % among them and with known porcine kobuviruses, respectively. The nucleotide sequence identities between our kobuvirus strains and those of human, bovine and canine kobuviruses were 69.4-70.7 %, 73.1-74.4 % and 67-70.7 %, respectively. Additionally, upon sequencing selected samples that showed consistent 720-bp RT-PCR bands while using the same primer set, we detected porcine astroviruses in our samples belonging to type 2 and type 3 mamastroviruses. To our knowledge, this study reports the first detection and molecular analysis of both porcine kobuviruses and astroviruses in an African region. Further studies are required to determine the role of these viruses in gastrointestinal infections of pigs in this region and to determine the genetic diversity of the circulating strains to develop accurate diagnostic tools and implement appropriate control strategies. PMID:24327095

Amimo, Joshua O; Okoth, Edward; Junga, Joseph O; Ogara, William O; Njahira, Moses N; Wang, Qiuhong; Vlasova, Anastasia N; Saif, Linda J; Djikeng, Appolinaire

2014-06-01

127

Molecular detection and genetic characterization of kobuviruses and astroviruses in asymptomatic local pigs in East Africa  

PubMed Central

In this study, swine fecal specimens (n = 251) collected from nursing and weaned piglets raised under smallholder production systems were screened for the presence of kobuviruses by RT-PCR. Porcine kobuviruses were detected in 13.1 % (33/251) of the samples. We demonstrated that porcine kobuvirus infections exist in indigenous pigs in Kenya and Uganda and that the prevalence was higher in young piglets than older pigs: nursing piglets (15 %), post-weaning (3-month-old) pigs (17 %), 4-month-old pigs (10 %). Genetic analysis of the partial RNA-dependent RNA polymerase (RdRp) region (690 nt) revealed that kobuviruses circulating in East Africa are diverse, sharing nucleotide sequence identities ranging from 89.7 to 99.1 % and 88 to 92.3 % among them and with known porcine kobuviruses, respectively. The nucleotide sequence identities between our kobuvirus strains and those of human, bovine and canine kobuviruses were 69.4-70.7 %, 73.1-74.4 % and 67-70.7 %, respectively. Additionally, upon sequencing selected samples that showed consistent 720-bp RT-PCR bands while using the same primer set, we detected porcine astroviruses in our samples belonging to type 2 and type 3 mamastroviruses. To our knowledge, this study reports the first detection and molecular analysis of both porcine kobuviruses and astroviruses in an African region. Further studies are required to determine the role of these viruses in gastrointestinal infections of pigs in this region and to determine the genetic diversity of the circulating strains to develop accurate diagnostic tools and implement appropriate control strategies.

Okoth, Edward; Junga, Joseph O.; Ogara, William O.; Njahira, Moses N.; Wang, Qiuhong; Vlasova, Anastasia N.; Djikeng, Appolinaire

2014-01-01

128

LLNL Middle East and North Africa research database  

SciTech Connect

The Lawrence Livermore National Laboratory (LLNL) Comprehensive Nuclear-Test-Ban Treaty Research and Development (CTBT R and D) program has made significant progress populating a comprehensive seismic research database (RDB) for seismic events and derived research products in the Middle East and North Africa (MENA). Our original ME/NA study region has enlarged and is now defined as an area including the Middle East, Africa, Europe, Southwest Asia, the Former Soviet Union and the Scandinavian/Arctic region. The LLNL RDB will facilitate calibration of all International Monitoring System (IMS) stations (primary and auxiliary) or their surrogates (if not yet installed) as well as a variety of gamma stations. The RDB provides not only a coherent framework in which to store and organize large volumes of collected seismic waveforms and associated event parameter information, but also provides an efficient data processing/research environment for deriving location and discrimination correction sur faces and capabilities. In order to accommodate large volumes of data from many sources with diverse formats the RDB is designed to be flexible and extensible in addition to maintaining detailed quality control information and associated metadata. Station parameters, instrument responses, phase pick information, and event bulletins were compiled and made available through the RDB. For seismic events in the MENA region occurring between 1976 and 1999, we have systematically assembled, quality checked and organized event waveforms; continuous seismic data from 1990 to present are archived for many stations. Currently, over 11,400 seismic events and 1.2 million waveforms are maintained in the RDB and made readily available to researchers. In addition to open sources of seismic data, we have established collaborative relationships with several ME/NA countries that have yielded additional ground truth and broadband waveform data essential for regional calibration and capability studies. Additional data and ground truth from other countries are also currently being sought. Research results, along with descriptive metadata are stored and organized within the LLNL RDB and prepared for delivery and integration into the Department of Energy (DOE) Knowledge Base (KB). Deliverables consist of primary data products (raw materials for calibration) and derived products (distilled from the organized raw seismological data). By combining travel-time observations, event characterization studies, and regional wave-propagation studies of the LLNL CTBT research team for ground truth events and regional events, we have assembled a library of ground truth information, event location correction surfaces, tomographic models and mine explosion histories required to support the ME/NA regionalization program. Corrections and parameters distilled from the LLNL RDB provide needed contributions to the KB for the MENA region and will enable the United States National Data Center (NDC) to effectively verify CTBT compliance. The LLNL portion of the DOE KB supports critical NDC pipeline functions in detection, location, feature extraction, discrimination, and analyst review in the Middle East and North Africa.

Dodge, D; Hauk, T; Moore, R M; O'Boyle, J; Ruppert, S

1999-07-23

129

The Elusive Access to Education for Muslim Women in Kenya from the Late Nineteenth Century to the "Winds of Change" in Africa (1890s to 1960s)  

ERIC Educational Resources Information Center

This article discusses the denial of access to education to Ismaili Muslim women in colonial Kenya during the 1890s and the 1960s. The Ismailis were part of the "Asians" in Africa, a working class, religious, Muslim immigrant group from India, circumscribed by poverty and a traditional culture, the orthodox elements of which, with regard to their…

Keshavjee, Rashida

2010-01-01

130

Responding to the Gender and Education Millennium Development Goals in South Africa and Kenya: Reflections on Education Rights, Gender Equality, Capabilities and Global Justice  

ERIC Educational Resources Information Center

This paper explores understandings of gender equality and education and the nature of global goal and target setting, drawing on empirical data collected in central and local government departments in Kenya and South Africa reflecting on their implementation of Millennium Development Goal (MDG) 1, concerned with poverty, MDG 2, concerned with…

Unterhalter, Elaine; North, Amy

2011-01-01

131

Building capacity of local governments, service users and carers to scale up provision for community mental health services in Africa: a case study of Kenya and Uganda  

Microsoft Academic Search

Purpose – The purpose of this case study is to describe the experiences of a development organization operating in Africa to make mental health services accessible to communities in Kenya and Uganda through partnerships. The lessons that can be learnt from this work are also considered. Design\\/methodology\\/approach – The paper is a case study that builds on operations research gathered

Joyce Kingori; Christina Angela Ntulo

2011-01-01

132

Event location in the Middle East and North Africa  

SciTech Connect

The Lawrence Livermore National Laboratory (LLNL) CTBT R{ampersand}D program has made significant progress towards improving the ability of the IMS seismic network to locate small-magnitude events in the Middle East and North Africa (MIYNA). Given that high-grade ground truth (such as known explosions) has been difficult to obtain in these regions, we have placed a significant effort towards the development of a teleseismically constrained seismic database that provides event locations good to within 20m km. This data set is used to make an initial evaluation of the effectiveness of calibration on the proposed seismic IMS network in the MWNA. Utilizing a surrogate IMS regional network in the Middle East we find that when a seismic event lies within the footprint of the recording network the uncalibrated event locations are good to within about 25 km of the teleseismically constrained (TC) location. Using region-specific static station corrections further reduces this difference to about 20 km. To obtain further improvement in location accuracy we have used the modified kriging technique developed by SNL to interpolate new travel-time corrections. We compare this technique withe other robust linear interpolation techniques with the goal of enhancing the estimation of travel-time corrections. This is important to TC events which we find can have large uncorrelated uncertainties. Finally, we are making a large effort to incorporate LLNL analyst picks on primary and secondary phases and develop azimuth and slownsess estimates horn current IMS arrays to improve/supplement the NEIC picks.

Schultz, C.A.; Myers, S.C.; Ruppert, S.D.

1997-07-01

133

Ten Years of Information Development in East, Central and Southern Africa.  

ERIC Educational Resources Information Center

Reviews 10 years of library and information developments in East, Central, and Southern Africa. Topics include school libraries; public libraries and rural information services; academic libraries; education and training; and professional library and information associations. (AEF)

Raseroka, H. Kay

1995-01-01

134

The Yellow, Fourmerous, Tubular Flowers of Kalanchoe marmorata from Central East Africa  

NSDL National Science Digital Library

The yellow, fourmerous, tubular flowers of Kalanchoe marmorata from Central East Africa illustrate two aspects of convergent evolution in Crassulaceae: sympetaly and variation in number of floral parts (either a reduction or increase).

Kindt, Frits; Hart, Henk'T

2004-03-09

135

In Search of Drifting Continents: A Field Program in East Africa and Related Course Activities  

ERIC Educational Resources Information Center

Describes the development of a month-long interterm course which involved a field trip to East Africa. An account of the field trip showing travel itineraries, costs, and other details of the trip is presented. (CP)

Romey, Bill

1975-01-01

136

Potential of Gdgts as Temperature Proxies Along Altitudinal Transects in East Africa  

NASA Astrophysics Data System (ADS)

Glycerol dialkyl glycerol tetraethers (GDGTs) are lipids of high molecular weight and include the isoprenoid GDGTs (iGDGTs) produced by Archaea and the branched GDGTs (brGDGTs) produced by unknown bacteria. Several indices were developed to describe the relationship between GDGT distribution and environmental parameters: the TEX86 (tetraether index of tetraethers consisting of 86 carbons), based on the relative abundances of iGDGTs in sediments, and the MBT (methylation index of branched tetraethers) and CBT (cyclisation ratio of branched tetraethers), based on the relative abundance of brGDGTs in soils. The TEX86 was shown to correlate well with water surface temperature, and the MBT and CBT with mean annual air temperature (MAAT) and soil pH. The GDGTs are increasingly used as temperature proxies. In this study, 41 surface soils were sampled along two altitudinal transects, from 500 to 2800 meters in Mount Rungwe (South western, Tanzania) and from 1897 to 3268 meters in Mount Kenya (Central Kenya). MAAT was reconstructed along the two transects using the MBT/CBT proxies. A linear correlation between the MBT/CBT-derived temperatures and the altitude (R2=0.83) was obtained by combining results of the two transects. The reconstructed temperature lapse rate (0.5 ° C/100 m) was consistent with the one determined from temperature measurements at six altitudes. These results show that the MBT/CBT is a suitable and robust temperature proxy in East Africa. In Mt. Rungwe soil samples, the TEX86 index, which was mainly used to reconstruct water surface temperatures until now, was found to vary linearly with altitude (R2=0.50). Such a relationship between TEX86 and altitude in organic soils has also been recently noticed in Mt. Xiangpi, China (Liu et al., 2013; R2=0.68). The adiabatic cooling of air with altitude could explain the TEX86 variation with altitude. If such a relationship is confirmed, the use of the TEX86 as a temperature proxy could be extended to soil environments. However, a lower correlation between TEX86 and altitude was observed for Mt. Kenya samples, implying that the environmental factors affecting the TEX86 values should be further investigated. Moreover, a given TEX86 value was shown to correspond to a much higher altitude (ca. 1800 m higher) for Mt. Xiangpi soils (Liu et al., 2013) than for Mt. Rungwe samples, suggesting that the geographical origin of the soils could also impact the TEX86 values. Therefore, a better understanding of the environmental mechanisms controlling the iGDGTs distribution in soils is needed prior any application of the TEX86 as a temperature proxy in these environments. REFERENCES Liu, W., Wang, H., Zhang, C.L., Liu, Z., He, Y., 2013. Organic Geochemistry 57, 76-83.

Coffinet, Sarah; Huguet, Arnaud; Omuombo, Christine; Williamson, David; Fosse, Céline; Anquetil, Christine; Derenne, Sylvie

2014-05-01

137

Effects of urban wastewater on crab and mollusc assemblages in equatorial and subtropical mangroves of East Africa  

NASA Astrophysics Data System (ADS)

Mangrove forests are known to accomplish crucial ecosystem functions and services. They are nursery areas for fish, prawns and crabs, which provide coastal communities with a variety of food, timber and chemicals, and protect coasts from catastrophic events, such as tsunamis. Recently, a novel ecological service has been proposed for mangrove systems, namely natural wastewater treatment wetlands. This hypothesis was based on experimental data collected mainly in Chinese mangrove systems, which proved that mangrove soils were efficient in absorbing nutrients. Moreover, sewage loading seemed harmless to both plants and benthic communities in these systems. However, before promoting the use of natural mangroves as pollution buffers, or constructed mangrove wetlands as sewage treatment facilities, more data are needed on their overall tolerance to organic loading. Differences in macrobenthos patterns were thus investigated between peri-urban mangroves and sites not affected by sewage disposal in East Africa. We assessed differences in epifaunal assemblages, comprising crabs and molluscs, employing multivariate ACI unbalanced analyses to compare peri-urban mangrove swamps with those characteristic of non-urban mangroves with similar ecological traits. The sampling design was spatially nested, replicates being assessed at equatorial (southern Kenya) and subtropical (southern Mozambique) sites. The results manifested a consistent increase in crab biomass at the peri-urban sites in both Kenya and Mozambique. Moreover, the peri-urban systems were richer than the non-urban mangroves, both in terms of fiddler crabs ( Uca spp.) which feed on benthic microalgae and bacteria, and sesarmids, such as Perisesarma guttatum and Neosarmatium meinerti, which feed on both substratum and leaf litter. The abundance of gastropods, in contrast, decreased significantly, especially in Kenya, mainly due to the disappearance of the mud whelk Terebralia palustris. The results thus indicate that, in East African mangrove systems, domestic wastewater has detectable effects on crabs and molluscs, suggesting their usefulness as bioindicators of its effects in mangroves. Transformed benthic patterns at the peri-urban sites indicated the need for further study of the actual potential of natural mangrove forests to absorb pollution in sewage treatment.

Cannicci, Stefano; Bartolini, Fabrizio; Dahdouh-Guebas, Farid; Fratini, Sara; Litulo, Carlos; Macia, Adriano; Mrabu, Elisha J.; Penha-Lopes, Gil; Paula, José

2009-09-01

138

LLNL Middle East and North Africa research database  

SciTech Connect

The Lawrence Livermore National Laboratory (LLNL) CTBT R{ampersand}D program has made significant progress assembling a comprehensive seismic database (DB) for events and derived parameters in the Middle East and North Africa (ME/NA). The LLNL research DB provides not only a coherent framework in which store and organize large volumes of collected seismic waveforms and associated event parameter information but also provides an efficient data processing/research environment. The DB is designed to be flexible and extensible in order to accommodate the large volumes of data in diverse formats from many sources in addition to maintaining detailed quality control and metadata. Researchers can make use of the relational nature of the DB and interactive analysis tools to quickly and efficiently process large volumes of data. Seismic waveforms have been systematically collected form a wide range of local and regional networks using numerous earthquake bulletins and converted a common format based on CSS3.O while undergoing quality control and corrections of errors. By combining traveltime observations, event characterization studies, and regional wave-propagation studies of the LLNL CTBT team, we are assembling a library of ground truth information and event location correction surfaces required to support the ME/NA regionalization program. Corrections and parameters distilled from the LLNL research DB will provide needed contributions to the DOE knowledge base for the ME/NA region and enable the USNDC and IDC to effectively verify CTBT compliance.

Ruppert, S.D.; Hauk, T.F.; Leach, R.

1997-07-15

139

An updated atlas of human helminth infections: the example of East Africa  

PubMed Central

Background Reliable and updated maps of helminth (worm) infection distributions are essential to target control strategies to those populations in greatest need. Although many surveys have been conducted in endemic countries, the data are rarely available in a form that is accessible to policy makers and the managers of public health programmes. This is especially true in sub-Saharan Africa, where empirical data are seldom in the public domain. In an attempt to address the paucity of geographical information on helminth risk, this article describes the development of an updated global atlas of human helminth infection, showing the example of East Africa. Methods Empirical, cross-sectional estimates of infection prevalence conducted since 1980 were identified using electronic and manual search strategies of published and unpublished sources. A number of inclusion criteria were imposed for identified information, which was extracted into a standardized database. Details of survey population, diagnostic methods, sample size and numbers infected with schistosomes and soil-transmitted helminths were recorded. A unique identifier linked each record to an electronic copy of the source document, in portable document format. An attempt was made to identify the geographical location of each record using standardized geolocation procedures and the assembled data were incorporated into a geographical information system. Results At the time of writing, over 2,748 prevalence surveys were identified through multiple search strategies. Of these, 2,612 were able to be geolocated and mapped. More than half (58%) of included surveys were from grey literature or unpublished sources, underlining the importance of reviewing in-country sources. 66% of all surveys were conducted since 2000. Comprehensive, countrywide data are available for Burundi, Rwanda and Uganda. In contrast, information for Kenya and Tanzania is typically clustered in specific regions of the country, with few records from areas with very low population density and/or environmental conditions which are unfavourable for helminth transmission. Information is presented on the prevalence and geographical distribution for the major helminth species. Conclusion For all five countries, the information assembled in the current atlas provides the most reliable, up-to-date and comprehensive source of data on the distribution of common helminth infections to guide the rational implementation of control efforts.

Brooker, Simon; Kabatereine, Narcis B; Smith, Jennifer L; Mupfasoni, Denise; Mwanje, Mariam T; Ndayishimiye, Onesime; Lwambo, Nicholas JS; Mbotha, Deborah; Karanja, Peris; Mwandawiro, Charles; Muchiri, Eric; Clements, Archie CA; Bundy, Donald AP; Snow, Robert W

2009-01-01

140

Learning from Logframes: Reflections on Three Educational Development Projects in East and Southern Africa  

ERIC Educational Resources Information Center

Against a backdrop of the importance of project evaluation in Africa, and the centrality of the project logical framework (logframes) to project evaluation, this paper reflects on experiences arising from evaluations of three educational development projects in East and Southern Africa. Each of these projects had a strong teacher development…

Harley, Ken

2005-01-01

141

Rural Development in Africa: A Bibliography. (Part I: General, Central, East). Training & Methods Series Number 16.  

ERIC Educational Resources Information Center

Compiled in July, 1971, this bibliography lists approximately 1,950 books, journal articles, and unpublished manuscripts dealing with rural development in Africa generally and in central and east Africa specifically. General entries appear under the following headings: agriculture; economic affairs; bibliography; law; economic and technical…

Anderson, Teresa, Comp.; And Others

142

Climate Change Impact Assessment and Adaptation Options in Vulnerable Agro-Landscapes in East-Africa  

Microsoft Academic Search

Climate change poses a risk to the livelihoods of large populations in the developing world, especially in Africa. In East Africa, climate change is expected to affect the spatial distribution and quantity of precipitation. The proposed project will assess aspects of climate impacts and adaptation options in Tanzania. The project will attempt to quantify (1) projected impacts including: variability in

D. Manful; K. Tscherning; K. Kersebaum; J. Dietz; O. Dietrich; C. Gomani; H. Böhm; M. Büchner; G. Lischeid; M. Ojoyi

2009-01-01

143

Late Quaternary palaeoclimatic oscillations in East Africa recorded by heavy minerals in the Nile delta  

Microsoft Academic Search

BECAUSE the Nile carries a load derived from markedly different geological terrains and climatic zones, it is expected that minera-logical study of deposits in its delta could help define changes in palaeoclimate affecting East Africa. Here we report measurements on heavy minerals in the Nile delta which can be used as distinct markers of climatic shifts over Africa during the

Alain Foucault; Daniel Jean Stanley

1989-01-01

144

Work Experience, Job-Fulfillment and Burnout among VMMC Providers in Kenya, South Africa, Tanzania and Zimbabwe  

PubMed Central

Background Human resource capacity is vital to the scale-up of voluntary medical male circumcision (VMMC) services. VMMC providers are at risk of “burnout” from performing a single task repeatedly in a high volume work environment that produces long work hours and intense work effort. Methods and findings The Systematic Monitoring of the Voluntary Medical Male Circumcision Scale-up (SYMMACS) surveyed VMMC providers in Kenya, South Africa, Tanzania, and Zimbabwe in 2011 (n?=?357) and 2012 (n?=?591). Providers self-reported on their training, work experience, levels of job-fulfillment and work fatigue/burnout. Data analysis included a descriptive analysis of VMMC provider characteristics, and both bivariate and multivariate analyses of factors associated with provider work fatigue/burnout. In 2012, Kenyan providers had worked in VMMC for a median of 31 months compared to South Africa (10 months), Tanzania (15 months), and Zimbabwe (11 months). More than three-quarters (78 – 99%) of providers in all countries in 2012 reported that VMMC is a personally fulfilling job. However, 67% of Kenyan providers reported starting to experience work fatigue/burnout compared to South Africa (33%), Zimbabwe (17%), and Tanzania (15%). Despite the high level of work fatigue/burnout in Kenya, none of the measured factors (i.e., gender, age, full-time versus part-time status, length of service, number of operations performed, or cadre) were significantly associated with work fatigue/burnout in 2011. In 2012, logistic regression found increases in age (p<.05) and number of months working in VMMC (p<.01) were associated with an increased likelihood of experiencing work fatigue/burnout, while higher career total VMMCs decreased the likelihood of experiencing burnout. Conclusion Given cross-country differences, further elucidation of cultural and other contextual factors that may influence provider burnout is required. Continuing to emphasize the contribution that providers make in the fight against HIV/AIDS is important.

Perry, Linnea; Rech, Dino; Mavhu, Webster; Frade, Sasha; Machaku, Michael D.; Onyango, Mathews; Aduda, Dickens S. Omondi.; Fimbo, Bennett; Cherutich, Peter; Castor, Delivette; Njeuhmeli, Emmanuel; Bertrand, Jane T.

2014-01-01

145

Unlocking the potential of tropical root crop biotechnology in east Africa by establishing a genetic transformation platform for local farmer-preferred cassava cultivars  

PubMed Central

Cassava genetic transformation capacity is still mostly restricted to advanced laboratories in the USA, Europe and China; and its implementation and maintenance in African laboratories has remained scarce. The impact of transgenic technologies for genetic improvement of cassava will depend largely on the transfer of such capabilities to researchers in Africa, where cassava has an important socioeconomic niche. A major constraint to the development of genetic transformation technologies for cassava improvement has been the lack of an efficient and robust transformation and regeneration system. Despite the success achieved in genetic modification of few cassava cultivars, including the model cultivar 60444, transgenic cassava production remains difficult for farmer-preferred cultivars. In this study, a protocol for cultivar 60444 developed at ETH Zurich was successfully implemented and optimized to establish transformation of farmer-preferred cassava cultivars popular in east Africa. The conditions for production and proliferation of friable embryogenic calli (FEC) and Agrobacterium-mediated transformation were optimized for three east African farmer-preferred cultivars (Ebwanatereka, Kibandameno and Serere). Our results demonstrated transformation efficiencies of about 14–22 independent transgenic lines per 100 mg of FEC for farmer-preferred cultivars in comparison to 28 lines per 100 mg of the model cultivar 60444. The presence, integration and expression of the transgenes were confirmed by PCR, Southern blot analysis and histochemical GUS assay. This study reports the establishment of a cassava transformation platform at International Institute of Tropical Agriculture (IITA) hosted by Biosciences eastern and central Africa (BecA) hub in Kenya and provides the basis for transferring important traits such as virus resistance and prolonged shelf-life to farmer-preferred cultivars in east Africa. We anticipate that such platform will also be instrumental to transfer technologies to national agricultural research systems (NARS) in sub-Saharan Africa.

Nyaboga, Evans; Njiru, Joshua; Nguu, Edward; Gruissem, Wilhelm; Vanderschuren, Herve; Tripathi, Leena

2013-01-01

146

Terrestrial heat flow in east and southern Africa  

Microsoft Academic Search

We report 26 new heat production measurements from Zimbabwe, Zambia and Tanzania, together with details and some revisions of 18 previous heat flow measurements by other investigtors from Kenya and Tanzania. These measurements come from Archean cratons, Proterozoic mobile belts, and Mesozoic and Cenozoic rifts. Heat flow data from eight new sites in the Archean Zimbabwe Craton are consistent with

Andrew A. Nyblade; Henry N. Pollack; D. L. Jones; Francis Podmore; Martin Mushayandebvu

1990-01-01

147

Understanding the nature of mantle upwelling beneath East-Africa  

NASA Astrophysics Data System (ADS)

The concept of hot upwelling material - otherwise known as mantle plumes - has long been accepted as a possible mechanism to explain hotspots occurring at Earth's surface and it is recognized as a way of removing heat from the deep Earth. Nevertheless, this theory remains controversial since no one has definitively imaged a plume and over the last decades several other potential mechanisms that do not require a deep mantle source have been invoked to explain this phenomenon, for example small-scale convection at rifted margins, meteorite impacts or lithospheric delamination. One of the best locations to study the potential connection between hotspot volcanism at the surface and deep mantle plumes on land is the East African Rift (EAR). We image seismic velocity structure of the mantle below EAR with higher resolution than has been available to date by including seismic data recorded by stations from many regional networks ranging from Saudi Arabia to Tanzania. We use relative travel-time tomography to produce P- velocity models from the surface down into the lower mantle incorporating 9250 ray-paths in our model from 495 events and 402 stations. We add smaller earthquakes (4.5 < mb < 5.5) from poorly sampled regions in order to have a more uniform data coverage. The tomographic results allow us to image structures of ~ 100-km length scales to ~ 1000 km depth beneath the northern East-Africa rift (Ethiopia, Eritrea, Djibouti, Yemen) with good resolution also in the transition zone and uppermost lower mantle. Our observations provide evidence that the shallow mantle slow seismic velocities continue trough the transition zone and into the lower mantle. In particular, the relatively slow velocity anomaly beneath the Afar Depression extends up to depths of at least 1000 km depth while another low-velocity anomaly beneath the Main Ethiopian Rift seems to be present in the upper mantle only. These features in the lower mantle are isolated with a diameter of about 400 km indicating deep multiple sources of upwelling that converge in broader low-velocity bodies along the rift axis at shallow depths. Moreover, our preliminary models show that the low-velocity feature in the transition zone and uppermost lower mantle beneath Afar trends to the northeast beneath the Red Sea and Saudi Arabia as opposed to being linked to the African Superplume towards the southwest.

Civiero, Chiara; Hammond, James; Goes, Saskia; Ahmed, Abdulhakim; Ayele, Atalay; Doubre, Cecile; Goitom, Berhe; Keir, Derek; Kendall, Mike; Leroy, Sylvie; Ogubazghi, Ghebrebrhan; Rumpker, Georg; Stuart, Graham

2014-05-01

148

Regional Arms Control Arrangements for Developing Areas. Arms and Arms Control in Latin America, the Middle East, and Africa.  

National Technical Information Service (NTIS)

Contents: Arms control in Latin America; Arms control in the Middle East; Arms control in North Africa; Arms control in sub-Saharan Africa; International regional organizations and regional arms control relationships between regional arms control agreemen...

1964-01-01

149

Food Strategies and Market Liberalization in Africa: Case Studies of Kenya, Tanzania, and Zimbabwe.  

National Technical Information Service (NTIS)

The report analyzes the food strategies of Kenya, Tanzania, and Zimbabwe during the 1980's. The overall objectives of these countries' food policies were to achieve food self-sufficiency and improve the nutritional status of the population. With p olicy r...

S. Shapouri M. Missiaen S. Rosen

1992-01-01

150

The Influence of European Pollution on Ozone in the Near East and Northern Africa  

NASA Technical Reports Server (NTRS)

We present a modeling study of the long-range transport of pollution from Europe, showing that European emissions regularly elevate surface ozone by as much as 20 ppbv in summer in northern Africa and the Near East. European emissions cause 50-150 additional violations per year (i.e. above those that would occur without European pollution) of the European health standard for ozone (8-h average greater than 120 micrograms per cubic meters or approximately 60 ppbv) in northern Africa and the Near East. We estimate that European ozone pollution is responsible for 50 000 premature mortalities globally each year, of which the majority occurs outside of Europe itself, including 37% (19 000) in northern Africa and the Near East. Much of the pollution from Europe is exported southward at low altitudes in summer to the Mediterranean Sea, northern Africa and the Near East, regions with favorable photochemical environments for ozone production. Our results suggest that assessments of the human health benefits of reducing ozone precursor emissions in Europe should include effects outside of Europe, and that comprehensive planning to improve air quality in northern Africa and the Near East likely needs to address European emissions.

Duncan, B. N.; West, J. J.; Yoshida, Y.; Fiore, A. M.; Ziemke, J. R.

2008-01-01

151

LLNL Middle East, North Africa and Western Eurasia Knowledge Base  

SciTech Connect

The Lawrence Livermore National Laboratory (LLNL) Ground-Based Nuclear Event Monitoring (GNEM) program has made significant progress populating a comprehensive Seismic Research Knowledge Base (SRKB) and deriving calibration parameters for the Middle East, North Africa and Western Eurasia (ME/NA/WE) regions. The LLNL SRKB provides not only a coherent framework in which to store and organize very large volumes of collected seismic waveforms, associated event parameter information, and spatial contextual data, but also provides an efficient data processing/research environment for deriving location and discrimination correction surfaces. The SRKB is a flexible and extensible framework consisting of a relational database (RDB), Geographical Information System (GIS), and associated product/data visualization and data management tools. This SRKB framework is designed to accommodate large volumes of data (almost 3 million waveforms from 57,000 events) in diverse formats from many sources (both LLNL derived research and integrated contractor products), in addition to maintaining detailed quality control and metadata. We have developed expanded look-up tables for critical station parameter information (including location and response) and an integrated and reconciled event catalog data set (including specification of preferred origin solutions and associated phase arrivals) for the PDE, CMT, ISC, REB and selected regional catalogs. Using the SRKB framework, we are combining traveltime observations, event characterization studies, and regional tectonic models to assemble a library of ground truth information and phenomenology (e.g. travel-time and amplitude) correction surfaces required for support of the ME/NA/WE regionalization program. We also use the SRKB to integrate data and research products from a variety of sources, such as contractors and universities, to merge and maintain quality control of the data sets. Corrections and parameters distilled from the LLNL SRKB provide essential contributions to the National Nuclear Security Administration Knowledge Base (NNSA KB) for the ME/NA/WE region and will improve capabilities for underground nuclear test monitoring. The LLNL research products will facilitate calibration of International Monitoring System (IMS) stations (primary and auxiliary), their surrogates (if not yet installed) and selected gamma stations necessary to complete the ME/NA/WE regionalization efforts. In addition to an overview of selected individual research products, we present an overview of our visualization, integration, validation, and organizational processes. Development of these processes and the LLNL SRKB was necessitated by both the very large amount of data and information involved, over 2 terabytes, and the varied data and research result formats utilized. Products assembled, integrated and validated using the LLNL SRKB are grouped into 5 major categories: (1) Reference and contextual information; (2) Detection data; (3) Calibration and ground truth data; (4) Event location products; and (5) Event identification products.

O'Boyle, J; Ruppert, S D; Hauk, T F; Dodge, D A; Ryall, F; Firpo, M A

2001-07-12

152

A Revised Holocene History of Lake Kivu, East Africa  

NASA Astrophysics Data System (ADS)

The great lakes of the East African Rift valley are a vast chain of lakes formed in a region of active tectonics. These large, deep lakes are relatively old and many (e.g. Tanganyika, Malawi, and Turkana) have greatly influenced our understanding of terrestrial, tropical East African paleoclimate. Lake Kivu (max depth, 485m) sits at the heart of these rift lakes, north of Lake Tanganyika between the Democratic Republic of the Congo and Rwanda (roughly 250 km west of Lake Victoria). At over 1,400 meters in elevation, this 2,060 km2 mesotrophic lake has a complex stratification regime imposed by hydrothermal springs and deep waters supersaturated at STP in CO2 and CH4 gasses. The active Virunga Volcanoes to the north of the lake supply heated, high-salinity waters below 280 meters water depth maintaining the modern crenogenic meromixis. Based on detailed studies of diatom assemblages and bulk sedimentology, previous workers have suggested this hydrothermal activity began roughly 5,000 years BP. Unfortunately, dating and stratigraphic correlations of these original cores from the 1970 Woods Hole Oceanographic Institution's expedition have been problematic. Here we offer an improved chronology and new carbonate analyses from cores recovered in 2012 and 2013. Our AMS radiocarbon ages come from six terrigeneous macrofossils spanning the last 9,100 years (cal BP). These ages suggest a rather high sedimentation rate on the order of 70cm/kyr, and hence, our 8 m-long core provides us with a high-resolution lake history for the past 10,000 years. Most notable over the past 5,000 years in the lake history is the repeated onset and cessation of carbonate deposition, punctuated by organic-rich intervals. Earlier studies of the Woods Hole cores placed the onset of carbonate deposition at ca. 11,000 years BP suggesting changes in lake hydrology (i.e. closed to open), while the abrupt cessation of carbonate was dated at ca. 5,000 years BP and attributed to the beginning of significant hydrothermal activity in the lake. However our new chronology places these events much younger with the first major onset of carbonate deposition occurring around 4,300 years BP and ceasing ca. 2,700 years BP. Indeed much of central and northern Africa began to dry out at this time, following the African Humid Period ca. 15,000 to 5,000 years BP. Arid conditions could certainly favor carbonate precipitation and hence our revised ages of deposition agree well with regional paleoclimate studies. This new age model opens up the carbonate record of Lake Kivu for reinterpretation. We are investigating the extent to which the carbonate signal is influenced by internal changes and hydrothermal activity or by climate.

Votava, J. E.; Johnson, T. C.; Hecky, R. E.

2013-12-01

153

The gravity field of the Red Sea and East Africa  

NASA Astrophysics Data System (ADS)

Reevaluation of all gravity data from the Red Sea, the Gulf of Aden and East Africa permitted the compilation of a new Bouguer anomaly map. The intensity of the gravity field and its regional pattern correlate closely with the topographic features of the region. The maximum Bouguer values (> + 100 mGal) are located over the median troughs of the Red Sea and Gulf of Aden. Dense juvenile oceanic crust in these rifts and intruding magmas in stretched continental areas produce excess mass responsible for the anomaly highs. In the Red Sea the orientation of the gravity highs is NW-SE in the south, turning to NE-SW in the north, almost parallel to the Aqaba-Dead Sea strike. This pattern reveals that the present basin axis is not identical with that which formed the Tertiary coastal margins and the pre-Red Sea zones of crustal weakness. In the Gulf of Aden, new oceanic crust along the Tadjura Trench and its eastward extension is also expressed in the Bouguer anomaly map by gravity highs and a sharp bending of the isolines. A maximum of approx. +150 mGal is located over the central section of the Sheba Ridge. Bouguer gravity values over the East African and Yemen Plateaus are of the order of -180 to -240 mGal, indicating significant crustal thickening. On the Somali Plateau, the Marda Fault also has a strong gravity signature that can be traced towards Somalia. By constraining crustal thickness and structure with seismic data and density values from the velocity distribution by means of the Nafe-Drake and Birch relationships, we computed density models for the crust and upper mantle. The crustal thickness is of the order of 40 km beneath the plateaus and only 5 to 6 km at the oceanized parts in the central and southern portions of the Red Sea median trough. The flanks of the southern Red Sea and the corresponding Arabian side are underlain by 12 to 16 km thick stretched continental type crust. Oceanization offshore Sudan and Egypt is asymmetrical. The continental crust terminates abruptly at about 20 km off the coastline, followed by an oceanic crust of early Miocene age that was produced in pull-apart basins. By contrast, the eastern side of the Red Sea trough offshore Saudi Arabia is floored by stretched continental crust that extends far into the sea. Seafloor spreading and the generation of oceanic crust in organized spreading centres are limited to the median troughs off Sudan and the northern part of Ethiopia and commenced approx. 5 m.y. BP. They are absent in the northern Red Sea, where crustal fracturing occurs only in pull-apart basins of Dead Sea-Aqaba orientation distributed in en-echelon pattern.

Makris, Jannis; Henke, Christian H.; Egloff, Frank; Akamaluk, Thomas

1991-11-01

154

Magnetotelluric images of the crustal structure of Chyulu Hills volcanic field, Kenya  

Microsoft Academic Search

Electromagnetic experiments were conducted in 1995 as part of a multidisciplinary research project to investigate the deep structure of the Chyulu Hills volcanic chain on the eastern flank of the Kenya Rift in East Africa. Transient electromagnetic (TEM) and broadband (120–0.0001 Hz) magnetotelluric (MT) soundings were made at eight stations along a seismic survey line and the data were processed

V. Sakkas; M. A. Meju; M. A. Khan; V. Haak; F. Simpson

2002-01-01

155

Rethinking geochemical feature of the Afar and Kenya mantle plumes and geodynamic implications  

Microsoft Academic Search

We discuss the spatial and temporal variation in the geochemistry of mantle sources which were sampled by the Eocene to Quaternary mafic magmas in the vicinity of the Afar and Kenya plume upwelling zones, East Africa. Despite the contributions of lithospheric and crustal sources, carefully screened Eocene to Quaternary mafic lavas display wide range of Sr-Nd-Pb isotopic and incompatible trace

Daniel Meshesha; Ryuichi Shinjo

2008-01-01

156

Petrology and geochemistry of granites from the Archæan terrain north of Lake Victoria, western Kenya  

Microsoft Academic Search

The Neoarchæan greenstone belt of western Kenya forms part of the Tanzania Craton of East Africa. Two groups of supracrustal rock sequences are recognised in this greenstone belt, namely a dominantly volcanic supergroup (the Nyanzian) and a dominantly sedimentary one (the Kavirondian); this is typical of many other Neoarchæan greenstone belts. The Nyanzian volcanics include mafic lavas (rarely ultramafic) which

Norbert Opiyo-Akech; John Tarney; M. Hoshino

1999-01-01

157

Meteorologic Influences on Plasmodium falciparum Malaria in the Highland Tea Estates of Kericho, Western Kenya  

Microsoft Academic Search

Recent epidemics of Plasmodium falciparum malaria have been observed in high-altitude areas of East Africa. Increased malaria incidence in these areas of unstable malaria transmission has been attributed to a variety of changes including global warming. To determine whether the reemergence of malaria in west- ern Kenya could be attributed to changes in meteorologic conditions, we tested for trends in

G. Dennis Shanks; Simon I. Hay; David I. Stern; Kimutai Biomndo; Robert W. Snow

158

Lithospheric thinning associated with rifting in East Africa  

NASA Technical Reports Server (NTRS)

The rate of ascent of the thermal perturbation of eruptive rock types in the Kenya Dome region can be calculated for depths of origin ranging from greater than 170 km to the lower crust (25-30 km) as combined with dated occurrences. An equation is derived and solved iteratively for ascent velocity at 10 km depth intervals from 150-30 km, assuming a thermal diffusivity of 1 sq mm/sec. For radii of 50 and 100 km and constant gradient increases within the range 55-60 C/km over the lithosphere-asthenosphere boundary (LAB) ascent depth range, the calculated rate of upwelling corresponds well with the results of a simple thermal model of lithospheric thinning. A 1 C/km change in gradient results approximately in a 0.55 Myr change in ascent time from 150 to 30 km, due to the increasing differential between the geotherm and the solidus with decreasing depths and the increasing rate of heat loss to the surface. It is suggested by the temporal-spatial-compositional relations of eruptives in the Kenya Dome region that there is a shallowing of magma source regions with time, implying encroachment of a thermal anomaly.

Wendlandt, R. F.; Morgan, R.

1982-01-01

159

Natural radioactivity and external dose in the high background radiation area of Lambwe East,Southwestern Kenya.  

PubMed

Absorbed dose rates around the North and South Ruri hills in Lambwe east, southwestern Kenya were measured using survey meters. The area lies roughly between latitudes 0°30'S and 1°00'S. It is bounded on the east by longitude 34°30'E and on the west by the shores of Lake Victoria and Winnam Gulf. The measured absorbed dose varies from 0.7 to 6.0 µGy h(-1), and the mean is 2.3 µGy h(-1). Assuming an outdoor occupancy factor of 0.4, the corresponding range and mean annual effective doses are 1.7-14.7 and 5.7 mSv, respectively. The average activity concentrations (ACs) of (232)Th, (226)Ra and (40)K in samples of soils and rocks from the area are 1397, 179 and 509 Bq kg(-1), respectively. Values of absorbed dose rates calculated from the ACs are general lower than those obtained from in situ measurements. Possible causes of these discrepancies were discussed in the paper. PMID:22535833

Achola, S O; Patel, J P; Mustapha, A O; Angeyo, H K

2012-12-01

160

Production objectives and management strategies of livestock keepers in south-east Kenya: implications for a breeding programme.  

PubMed

A survey of pastoralist and agropastoralist households in south-east Kenya was conducted to determine their production objectives and management strategies in order to optimize and extend a breeding programme for indigenous small East African Shorthorn Zebu cattle. The reasons for keeping cattle and the breed/trait preferences identified reflect the multiple objectives of the livestock keepers, with both adaptive traits and productive/reproductive traits rated as important. Although the Maasai and Kamba zebu (M&KZ) breeds were ranked highly with regard to adaptive traits, the population is considered to have been in decline over recent years. In order to promote the conservation and sustainable use of the M&KZ cattle, the formation of an open nucleus breeding scheme is recommended. In particular, such a scheme would be able to address several existing constraints (e.g. individual herds are very small and communal use of pastures/water makes controlled mating difficult). Such interventions would require the full participation of the livestock keepers, as well as ensuring that a holistic approach to species and breed attributes is taken into account in setting breeding goals, such that the full array of contributions that livestock make to livelihoods and the genetic characteristics related to these contributions are fully incorporated into the programme. PMID:16619880

Mwacharo, J M; Drucker, A G

2005-11-01

161

On the relation between rainfall and the Normalized Difference Vegetation Index for diverse vegetation types in East Africa  

Microsoft Academic Search

This study is an investigation of the relation between the Normalized Difference Vegetation Index (NDVI) and rainfall in East Africa. The temporal and spatial patterns of both variables and their inter-relationships are evaluated. The NDVI and rain-fall associations are analysed for ten vegetation formations of East Africa: four forest zones, two woodland zones, and four drier bush, thicket and grassland

M. L. DAVENPORT; S. E. NICHOLSON

1993-01-01

162

Stratiform precipitation production over sub-Saharan Africa and the tropical East Atlantic as observed by TRMM  

Microsoft Academic Search

SUMMARY Convective systems over sub-Saharan Africa and the tropical East Atlantic have distinct geographical and seasonal variations in convective intensity and stratiform precipitation production as observed by the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar. Over the East Atlantic, convective rain rates are lower and the percentage of total rain that is stratiform is higher compared to over West Africa.

Courtney Schumacher; Robert A. Houze

2006-01-01

163

Middle East, North Africa and Western Eurasia Seismic Research Database  

SciTech Connect

The National Nuclear Security Administration (NNSA) Ground-Based Nuclear Explosion Monitoring Research and Engineering (GNEM R&E) Program at Lawrence Livermore National Laboratory (LLNL) has made significant progress populating a comprehensive Seismic Research Database (SRDB) used for deriving seismic calibration parameters for the Middle East, North Africa and Western Eurasia (ME/NA/WE) regions. In addition to an overview of select individual information products, we present an overview of our visualization, integration, validation, and organizational processes. Development of these processes and the LLNL SRDB was necessitated by both the very large amount of data and information involved (over 15 terabytes) and the varied data and research result formats utilized. The LLNL SRDB allows for the collection of raw and contextual seismic data used in research, provides an interface for researchers to access data, provides a framework to store research results and integrate datasets, and supports assembly, integration and dissemination of datasets to the NNSA Knowledge Base (KB). The LLNL SRDB is a flexible and extensible framework consisting of a relational database (RDB), Geographical Information System (GIS), and associated product/data visualization and data management tools. This framework is designed to accommodate large volumes of data in diverse formats from many sources (both in-house-derived research and integrated contractor products), in addition to maintaining detailed quality control and metadata. In order to efficiently organize information within the LLNL SRDB, it was necessary to automate procedures needed to create and update database tables, but a large effort is still required by technicians and scientists to load special datasets, review results of automated processing and resolve quality issues. The LLNL SRDB currently has 3 million reconciled event origins and arrivals from several global, regional and local seismic bulletins and 30 million waveforms from 570,000 seismic events. We also use the LLNL SRDB for integration and have developed procedures, algorithms, and tools, organized as a tool set called KBITS, which permits datasets to be merged and dataset quality control to be maintained. KBITS can be used to integrate waveform and bulletin data into unified datasets. This suite of tools is now being used by LLNL for content development and by Sandia National Laboratory to assist in creation of the KB. It enables inclusion of data from contractors, universities, and NNSA collaborators for content development and to provide coherent, reconciled and integrated results to the NNSA KB. The SRDB integration framework also supports and facilitates NNSA ROA and BAA projects. The LLNL SRDB provides the basis for synergistic development of all LLNL GNEM R&E Program research. It is not only a coherent framework in which to store and organize very large volumes of collected seismic waveforms, associated event parameter information, and spatial contextual data, but also provides an efficient data processing/research environment for deriving a wide range of information products required to support the ME/NA/WE regionalization program. Products assembled, integrated and validated using the LLNL SRDB are grouped into five main categories: reference and contextual information, detection data, calibration and groundtruth data, event location products and event identification products. Using the LLNL SRDB, we are combining travel-time observations, event characterization studies, and regional tectonic models to assemble a library of ground-truth information and phenomenology (e.g. travel-time and amplitude) correction surfaces. Corrections and parameters distilled from the LLNL SRDB provide essential contributions to the NNSA KB for the ME/NA/WE region and facilitate calibration of seismic monitoring stations, thereby improving capabilities for underground nuclear explosion monitoring.

O'Boyle, J L; Ruppert, S D; Hauk, T F; Dodge, D A; Ganzberger, M D; Ryall, F

2003-07-14

164

Some Like It Hot: The Influence and Implications of Climate Change on Coffee Berry Borer (Hypothenemus hampei) and Coffee Production in East Africa  

PubMed Central

The negative effects of climate change are already evident for many of the 25 million coffee farmers across the tropics and the 90 billion dollar (US) coffee industry. The coffee berry borer (Hypothenemus hampei), the most important pest of coffee worldwide, has already benefited from the temperature rise in East Africa: increased damage to coffee crops and expansion in its distribution range have been reported. In order to anticipate threats and prioritize management actions for H. hampei we present here, maps on future distributions of H. hampei in coffee producing areas of East Africa. Using the CLIMEX model we relate present-day insect distributions to current climate and then project the fitted climatic envelopes under future scenarios A2A and B2B (for HADCM3 model). In both scenarios, the situation with H. hampei is forecasted to worsen in the current Coffea arabica producing areas of Ethiopia, the Ugandan part of the Lake Victoria and Mt. Elgon regions, Mt. Kenya and the Kenyan side of Mt. Elgon, and most of Rwanda and Burundi. The calculated hypothetical number of generations per year of H. hampei is predicted to increase in all C. arabica-producing areas from five to ten. These outcomes will have serious implications for C. arabica production and livelihoods in East Africa. We suggest that the best way to adapt to a rise of temperatures in coffee plantations could be via the introduction of shade trees in sun grown plantations. The aims of this study are to fill knowledge gaps existing in the coffee industry, and to draft an outline for the development of an adaptation strategy package for climate change on coffee production. An abstract in Spanish is provided as Abstract S1.

Vega, Fernando E.; Davis, Aaron; Borgemeister, Christian; Chabi-Olaye, Adenirin

2011-01-01

165

Some like it hot: the influence and implications of climate change on coffee berry borer (Hypothenemus hampei) and coffee production in East Africa.  

PubMed

The negative effects of climate change are already evident for many of the 25 million coffee farmers across the tropics and the 90 billion dollar (US) coffee industry. The coffee berry borer (Hypothenemus hampei), the most important pest of coffee worldwide, has already benefited from the temperature rise in East Africa: increased damage to coffee crops and expansion in its distribution range have been reported. In order to anticipate threats and prioritize management actions for H. hampei we present here, maps on future distributions of H. hampei in coffee producing areas of East Africa. Using the CLIMEX model we relate present-day insect distributions to current climate and then project the fitted climatic envelopes under future scenarios A2A and B2B (for HADCM3 model). In both scenarios, the situation with H. hampei is forecasted to worsen in the current Coffea arabica producing areas of Ethiopia, the Ugandan part of the Lake Victoria and Mt. Elgon regions, Mt. Kenya and the Kenyan side of Mt. Elgon, and most of Rwanda and Burundi. The calculated hypothetical number of generations per year of H. hampei is predicted to increase in all C. arabica-producing areas from five to ten. These outcomes will have serious implications for C. arabica production and livelihoods in East Africa. We suggest that the best way to adapt to a rise of temperatures in coffee plantations could be via the introduction of shade trees in sun grown plantations. The aims of this study are to fill knowledge gaps existing in the coffee industry, and to draft an outline for the development of an adaptation strategy package for climate change on coffee production. An abstract in Spanish is provided as Abstract S1. PMID:21935419

Jaramillo, Juliana; Muchugu, Eric; Vega, Fernando E; Davis, Aaron; Borgemeister, Christian; Chabi-Olaye, Adenirin

2011-01-01

166

Dispersal and colonisation, long and short chronologies: how continuous is the Early Pleistocene record for hominids outside East Africa?  

Microsoft Academic Search

This paper examines the evidence for hominids outside East Africa during the Early Pleistocene. Most attention has focused recently on the evidence for or against a late Pliocene dispersal, ca. 1.8 Ma., of hominids out of Africa into Asia and possibly southern Europe. Here, the focus is widened to include North Africa as well as southern Asia and Europe, as

Robin Dennell

2003-01-01

167

Food Production Impacts of Climate Change and Land Use Change in East Africa  

Microsoft Academic Search

Impacts of regional and global-scale environmental changes on human systems are of great concern for assessing impacts on food production, particularly in highly heterogeneous locations like East Africa with large, vulnerable populations. In assessing climate impacts, enhanced greenhouse gases (GHG) as well as land cover\\/land use change (LCLUC) each have potential impacts. We used a regional climate model derived from

G. Alagarswamy; N. J. Moore; B. M. Lofgren; B. C. Pijanowski; P. Thornton; J. M. Olson; J. A. Andresen; P. Z. Yanda; J. Qi

2008-01-01

168

Black leaf streak and viral leaf streak: New banana diseases in East Africa  

Microsoft Academic Search

Black leaf streak, caused by Mycosphaerella fijiensis a virulent pathogen of bananas and plantains, is recorded from Zanzibar. This is the first record of this important pathogen from East Africa. Viral leaf streak of bananas is also identified from Zanzibar. The presence of panama disease and high infestations of root nematode are also noted.

A. J. Dabek; J. M. Waller

1990-01-01

169

Lessons from Mount Kilimanjaro: Schooling, Community, and Gender in East Africa.  

ERIC Educational Resources Information Center

This book presents an ethnographic study of a school and community in East Africa. It focuses on the role school plays in the development of the children's identity and relationships to their parents and community, and in the development of the region. At issue here are the competing influences of Western modernity and the cultural traditions of…

Stambach, Amy

170

Ancient glaciations and hydrocarbon accumulations in North Africa and the Middle East  

Microsoft Academic Search

At least six glaciations are purported to have affected North Africa and the Middle East region over the last one billion years, including two in the Cryogenian (Neoproterozoic), Hirnantian (Late Ordovician), Silurian, Carboniferous and Early Permian events. The sedimentary record associated with these glaciations, together with the intensity to which each has been investigated, is highly variable. As hydrocarbon exploration

Daniel Paul Le Heron; Jonathan Craig; James L. Etienne

2009-01-01

171

A Review Of Mercury in Lake Victoria, East Africa: Implications for Human and Ecosystem Health  

Microsoft Academic Search

Lake Victoria, East Africa, has been the site of many recent studies measuring mercury (Hg) concentrations in water, fish, sediment, soil, and humans. Most of these studies were motivated by concerns about Hg contamination from processing of gold ore on the southern shores. Total Hg (THg) concentrations in fish were usually below permissible World Health Organization (WHO) concentrations and international

Linda M. Campbell; D. G. Dixon; R. E. Hecky

2003-01-01

172

Rayleigh wave group velocity dispersion across Northern Africa, Southern Europe and the Middle East.  

National Technical Information Service (NTIS)

THis report presents preliminary results from a large scale study of surface wave group velocity dispersion throughout Northern Africa, the Mediterranean, Southern Europe and the Middle East. Our goal is to better define the 3D lithospheric shear-wave vel...

D. E. McNamara W. R. Walter

1997-01-01

173

Teacher Incentives in the Middle East and North Africa Region: The Shortcomings.  

ERIC Educational Resources Information Center

Examines incentives for remaining in teaching among educators in the Middle East and North Africa. Surveys of teachers in nine countries indicate that school facilities and classrooms are generally in poor conditions, classes are crowded, evaluation or supervision of instruction is almost nonexistent, and inservice training is ineffective.…

Abdo, Huda A.

2001-01-01

174

Education in the Middle East and North Africa: The Current Situation and Future Challenges  

ERIC Educational Resources Information Center

This paper investigates the educational development in the Middle East and North Africa, drawing on data from different international and national institutions. The paper begins with a review of similarities between countries within the region, and continues by investigating the situation of basic education, literacy rates and quality of…

Akkari, Abdeljalil

2004-01-01

175

The origins, dynamics and generation of Trypanosoma brucei rhodesiense epidemics in East Africa  

Microsoft Academic Search

The history of sleeping sickness in East Africa has provoked controversy not only about the origins and spread of the disease, but also the identity of the causative organisms involved. Molecular methodology1 has shed new light on the genetic makeup of the organisms involved in recent epidemics. Here, Geoff Hide, Andrew Tait, Ian Maudlin and Susan Welburn discuss these new

G. Hide; A. Tait; I. Maudlin; S. C. Welburn

1996-01-01

176

Dry spell analysis and maize yields for two semi-arid locations in east Africa  

Microsoft Academic Search

High variability in rainfall occurrence and amounts together with high evaporative demand create severe constraints for crop growth and yields in dry sub-humid and semi-arid farming areas in east Africa. Meteorological analyses on rainfall distribution are common, but generally focus on assessing drought occurrence on annual and seasonal basis. This paper presents two types of seasonal dry spell analysis, using

Jennie Barron; Johan Rockström; Francis Gichuki; Nuhu Hatibu

2003-01-01

177

Upper mantle seismic velocity structure beneath Tanzania, east Africa: Implications for the stability of cratonic lithosphere  

Microsoft Academic Search

The assertion of cratonic stability put forward in the model for deep continental structure can be tested by examining upper mantle structure beneath the Tanzania Craton, which lies within a tectonically active region in east Africa. Tomographic inversions of about 1200 teleseismic P and $ travel times indicate that high-velocity lithosphere beneath the Tanzania Craton extends to a depth of

Jeroen Ritsema; Andrew A. Nyblade; Thomas J. Owens; Charles A. Langston; John C. VanDecar

1998-01-01

178

The Middle Stone Age of East Africa and the beginnings of regional identity  

Microsoft Academic Search

The history of research into the Middle Stone Age of East Africa and the present state of knowledge of this time period is examined for the region as a whole, with special reference to paleoenvironments. The known MSA sites and occurrences are discussed region by region and attempts are made to fit them into a more precise chronological framework and

J. Desmond Clark

1988-01-01

179

War and ethnicity: Global connections and local violence in North East Africa and former Yugoslavia  

Microsoft Academic Search

Many of today's wars are explained (by observers) and justified (by participants) as the result of deep and ineradicable ethnic differences. But ethnic differences are not given in nature and the relationship between ethnicity and war is not a simple matter of cause and effect. Five questions are considered in the light of recent internal wars in North East Africa

David Turton

1997-01-01

180

Sustainable wastewater management for small communities in the Middle East and North Africa  

Microsoft Academic Search

Accelerated expansion of wastewater services to small communities in the Middle East and North Africa (MENA) is essential in order to address serious concerns over water scarcity and pollution in addition to meeting the demand for convenience and protecting public health. Centralized and conventional wastewater systems are currently the preferred choice of planners and decision-makers in MENA. Water and funding

H. A. Bakir

2001-01-01

181

The quality of education in the Middle East and North Africa (MENA)  

Microsoft Academic Search

The quality of education is an issue in every region undergoing economic change, hence it is a universal issue. Where the quality of education is already low, the need to raise it is more urgent. In the Middle East and North Africa, data on educational quality are scarce. Nevertheless, available data would suggest that the quality of education is low.

Stephen P. Heyneman

1997-01-01

182

Muslims in East Africa Develop Their Own Higher-Education Options.  

ERIC Educational Resources Information Center

Private Islamic universities are increasing in East Africa, where higher education is increasingly privatized and diversified. The progressive scholars behind the trend are seeking opportunities for dynamic encounters between Islam and modern secular disciplines. The model is the 11-year-old Islamic University in Uganda, which is now attempting to…

Useem, Andrea

1999-01-01

183

Water: The Hydraulic Parameter of Conflict in the Middle East and North Africa.  

National Technical Information Service (NTIS)

This is the 35th volume in the Occasional Paper series of the U.S. Air Force Institute for National Security Studies (INSS). Water is a primary concern of most governments in the Middle East and North Africa. A myriad of synergistic variables are exponent...

S. D. Kiser

2000-01-01

184

Concentrating solar power for seawater desalination in the Middle East and North Africa  

Microsoft Academic Search

The paper presents a long-term scenario for the demand of freshwater in the Middle East and North Africa (MENA) and shows how it may be covered by a better use of the existing renewable water sources and by sea water desalination powered with solar energy. Growth of population and economy, increasing urbanization and industrialization, and the rather limited natural resources

Franz Trieb; Hans Müller-Steinhagen

2008-01-01

185

Implications of the Growth of China and India for the Middle East and North Africa  

Microsoft Academic Search

The Middle East and North Africa (MENA) region is expected to benefit more than most other regions from continued rapid growth in China and India. This paper analyzes the trade-related implications of this growth for the MENA countries using a global general equilibrium model, modified to take into account the focus of China and, increasingly, India on exports of manufactures

Elena Ianchovichina; Maros Ivanic; Will Martin

186

Sunspots, El Niño, and the levels of Lake Victoria, East Africa  

Microsoft Academic Search

An association of high sunspot numbers with rises in the level of Lake Victoria, East Africa, has been the focus of many investigations and vigorous debate during the last century. In this paper, we show that peaks in the ?11-year sunspot cycle were accompanied by Victoria level maxima throughout the 20th century, due to the occurrence of positive rainfall anomalies

J. Curt Stager; Alexander Ruzmaikin; Declan Conway; Piet Verburg; Peter J. Mason

2007-01-01

187

Traditional Music of East Africa: Experiencing "Ngoma" in Tanzania  

ERIC Educational Resources Information Center

The concept of ngoma is present throughout Eastern and Southern Africa. Ngoma refers to the tradition of expression via music, drumming, dance, and storytelling. History, values, education, and even identity can be transmitted between generations. This article traces the experiences of a music teacher from the United States traveling and studying…

Howard, Karen

2014-01-01

188

Hepatitis B epidemiology in Asia, the Middle East and Africa  

Microsoft Academic Search

Asia and Africa have previously been classified as areas of high endemicity for hepatitis B virus (HBV), but in some countries highly effective vaccination programmes have shifted this pattern towards intermediate or low endemicity. Thus, China is now the only country in Asia where HBV endemicity is high. Countries with intermediate endemicity include India, Korea, the Philippines, Taiwan and Thailand,

Francis André

2000-01-01

189

Influence of historical land use transformation on the Greater Horn of Africa climate: Case Study over Kenya  

NASA Astrophysics Data System (ADS)

The behavior of the planetary boundary layer (PBL) is largely influenced by its contact with the planetary surface. The land surface characteristics that include the surface roughness, albedo, moisture availability among others control the Land-atmosphere interaction. These surface conditions play a major role in turbulence transfer of mass, momentum and heat and provide a vital physical link between the atmosphere and the surface of the earth. In this study, we investigate relationship between land use/cover and regional patterns of precipitation and temperature over central highlands of the Greater Horn of Africa (Kenya) using both remote sensing techniques and model simulations. ERDAS imagine 9.3, a remote sensing tool, is employed in land use/land cover classification over Kenya for realistic model land cover representation. Idealized land use/cover scenarios (borrowing from the ERDAS classifications) are used in regional climate simulations (using RegCM3 model) since existing observations are inadequate to determine the extent and severity of historical land use changes. Our case study periods are for the years 1986, 1995 and 2000. We also focus on the two primary rainfall season over the study domain centered on March-April-May (MAM) and October-November-December (OND). Preliminary results shows areas of rainfall maximum over the western, central and coastal parts of Kenya tend to be co-located with Forest and agricultural zones. Analysis of precipitation variability over the years 1986, 1995 and 2000 in the neighborhood of inland lakes, in particular Lake Victoria (largest lake in Africa) shows persistent precipitation throughout the year. This we attribute to local convection induced by topography and Lake induced circulations and associated convection. Our analysis also shows a decline in MAM seasonal rainfall between the period 1986 to 2000 and a slight increase of OND seasonal rainfall over the same period. The decrease in MAM seasonal rainfall can be attributed to environmental (forests) degradation and other climate phenomena, which we will later investigate in our modeling work. MAM seasonal rainfall has earlier been linked to local scale factors while OND seasonal rainfall is linked to influence of large scale phenomena over the region. Temperature anomalies over the same region show temperature fluctuations to be minimal over the western and central parts of the country co-located with agricultural and forests zones. Nonetheless seasonal temperature anomalies shows an increase of approximately 0.50C during the MAM season between the periods 1986 and 2000 and approximately 0.20C in OND season over the same time period. Our finding in this study is important in the sense that detecting land use/land cover change accurately at appropriate scale and in a timely manner will help to better understand their impacts on climate and potentially improve the predictability and prediction of regional climates on both short and long time scales.

Anyah, R. O.; Otieno, V. O.

2010-12-01

190

High-elevation amplification of warming since the Last Glacial Maximum in East Africa: New perspectives from biomarker paleotemperature reconstructions  

NASA Astrophysics Data System (ADS)

Tropical lapse rate variability on glacial/interglacial time scales has been hotly debated since the publication of CLIMAP in 1976. Low-elevation paleotemperature reconstructions from the tropics have repeatedly shown less warming from the Last Glacial Maximum (LGM) to present than reconstructions from high elevations, leading to widespread difficulty in estimating the true LGM-present temperature change in the tropics. This debate is further complicated by the fact that most paleotemperature estimates from high elevations in the tropics are derived from pollen- and moraine-based reconstructions of altitudinal shifts in vegetation belts and glacial equilibrium line altitudes (ELAs). These traditional approaches rely on the assumption that lapse rates have remained constant through time. However, this assumption is problematic in the case of the LGM, when pervasive tropical aridity most likely led to substantial changes in lapse rates. Glycerol dialkyl glycerol tetraethers (GDGTs) can be used to reconstruct paleotemperatures independent of hydrological changes, making them the ideal proxy to reconstruct high elevation temperature change and assess lapse rate variability through time. Here we present two new equatorial paleotemperature records from high elevations in East Africa (Lake Rutundu, Mt. Kenya and Lake Mahoma, Rwenzori Mountains, Uganda) based on branched GDGTs. Our record from Lake Rutundu shows deglacial warming starting near 17 ka and a mid-Holocene thermal maximum near 5 ka. The overall amplitude of warming in the Lake Rutundu record is 6.8×1.0°C from the LGM to the present, with mid-Holocene temperatures 1.6×0.9°C warmer than modern. Our record from Lake Mahoma extends back to 7 ka and shows similar temperature trends to our record from Lake Rutundu, indicating similar temporal resolution of high-elevation temperature change throughout the region. Combining these new records with three previously published GDGT temperature records from different elevations in East Africa (Sacred Lake, Lake Tanganyika, and Lake Malawi), we are able to reconstruct a continuous record of lapse rates and freezing level heights (FLHs) back to the LGM. We find that tropical lapse rates have varied widely over the last 22 ky, with the largest (lowest) lapse rate (FLH) around the LGM, while the smallest (highest) lapse rate (FLH) occurs during the mid-Holocene, confirming the amplification of warming at high altitudes between the LGM and present. These lapse rate and FLH reconstructions match records of regional hydrological variability, confirming the importance of glacial/interglacial humidity variations on altitudinal temperature gradients in the tropics. Furthermore, the FLH record largely matches records of tropical glacier ELA changes, indicating that warming from LGM-present was likely amplified at high altitudes throughout the tropics.

Loomis, S. E.; Russell, J. M.; Kelly, M. A.; Eggermont, H.; Verschuren, D.

2013-12-01

191

Provider Attitudes toward the Voluntary Medical Male Circumcision Scale-Up in Kenya, South Africa, Tanzania and Zimbabwe  

PubMed Central

Background Countries participating in voluntary medical male circumcision (VMMC) scale-up have adopted most of six elements of surgical efficiency, depending on national policy. However, effective implementation of these elements largely depends on providers' attitudes and subsequent compliance. We explored the concordance between recommended practices and providers' perceptions toward the VMMC efficiency elements, in part to inform review of national policies. Methods and Findings As part of Systematic Monitoring of the VMMC Scale-up (SYMMACS), we conducted a survey of VMMC providers in Kenya, South Africa, Tanzania, and Zimbabwe. SYMMACS assessed providers' attitudes and perceptions toward these elements in 2011 and 2012. A restricted analysis using 2012 data to calculate unadjusted odds ratios and 95% confidence intervals for the country effect on each attitudinal outcome was done using logistic regression. As only two countries allow more than one cadre to perform the surgical procedure, odds ratios looking at country effect were adjusted for cadre effect for these two countries. Qualitative data from open-ended responses were used to triangulate with quantitative analyses. This analysis showed concordance between each country's policies and provider attitudes toward the efficiency elements. One exception was task-shifting, which is not authorized in South Africa or Zimbabwe; providers across all countries approved this practice. Conclusions The decision to adopt efficiency elements is often based on national policies. The concordance between the policies of each country and provider attitudes bodes well for compliance and effective implementation. However, study findings suggest that there may be need to consult providers when developing national policies.

Mavhu, Webster; Frade, Sasha; Yongho, Ann-Marie; Farrell, Margaret; Hatzold, Karin; Machaku, Michael; Onyango, Mathews; Mugurungi, Owen; Fimbo, Bennett; Cherutich, Peter; Rech, Dino; Castor, Delivette; Njeuhmeli, Emmanuel; Bertrand, Jane T.

2014-01-01

192

Systematic Monitoring of Voluntary Medical Male Circumcision Scale-Up: Adoption of Efficiency Elements in Kenya, South Africa, Tanzania, and Zimbabwe  

PubMed Central

Background SYMMACS, the Systematic Monitoring of the Voluntary Medical Male Circumcision Scale-up, tracked the implementation and adoption of six elements of surgical efficiency— use of multiple surgical beds, pre-bundled kits, task shifting, task sharing, forceps-guided surgical method, and electrocautery—as standards of surgical efficiency in Kenya, South Africa, Tanzania, and Zimbabwe. Methods and Findings This multi-country study used two-staged sampling. The first stage sampled VMMC sites: 73 in 2011, 122 in 2012. The second stage involved sampling providers (358 in 2011, 591 in 2012) and VMMC procedures for observation (594 in 2011, 1034 in 2012). The number of VMMC sites increased significantly between 2011 and 2012; marked seasonal variation occurred in peak periods for VMMC. Countries adopted between three and five of the six elements; forceps-guided surgery was the only element adopted by all countries. Kenya and Tanzania routinely practiced task-shifting. South Africa and Zimbabwe used pre-bundled kits with disposable instruments and electrocautery. South Africa, Tanzania, and Zimbabwe routinely employed multiple surgical bays. Conclusions SYMMACS is the first study to provide data on the implementation of VMMC programs and adoption of elements of surgical efficiency. Findings have contributed to policy change on task-shifting in Zimbabwe, a review of the monitoring system for adverse events in South Africa, an increased use of commercially bundled VMMC kits in Tanzania, and policy dialogue on improving VMMC service delivery in Kenya. This article serves as an overview for five other articles following this supplement.

Bertrand, Jane T.; Rech, Dino; Omondi Aduda, Dickens; Frade, Sasha; Loolpapit, Mores; Machaku, Michael D.; Oyango, Mathews; Mavhu, Webster; Spyrelis, Alexandra; Perry, Linnea; Farrell, Margaret; Castor, Delivette; Njeuhmeli, Emmanuel

2014-01-01

193

Lettowia, a new genus of Vernonieae from East Africa (Asteraceae)  

PubMed Central

Abstract A new genus, Lettowia H. Rob. & Skvarla is named for the single East African species originally described as Vernonia nyassae Oliv. Its pollen is lophate and triporate, with a perforated tectum restricted to the muri. The new genus is placed near Vernoniastrum in the subtribe Erlangeinae.

Robinson, Harold; Skvarla, John J.

2013-01-01

194

Plate Tectonics of the Red Sea and East Africa  

Microsoft Academic Search

The relative motion between the plates on each side of the East African Rift Valley can be obtained from the opening of the Red Sea and the Gulf of Aden. The calculated direction of relative motion agrees well with fault plane solutions for earthquakes north of the equator.

D. P. McKenzie; D. Davies; P. MOLNAR

1970-01-01

195

Carbon dioxide measurements in tropical east African biomes  

Microsoft Academic Search

From January 1977 through May 1978 atmospheric COâ concentrations were measured hourly and\\/or continuously at bimonthly intervals over periods varying from 5 to 8 days at 10 different locations in Kenya, East Africa. During each of these periods, at least two, and in some cases five, vertical profile measurements of COâ concentrations were conducted above different biomes. A large diurnal

R. C. Schnell; S.-A. Odh; L. N. Njau

1981-01-01

196

The Symptom and Genetic Diversity of Cassava Brown Streak Viruses Infecting Cassava in East Africa  

PubMed Central

The genetic and symptom diversity of six virus isolates causing cassava brown streak disease (CBSD) in the endemic (Kenya, Mozambique, and Tanzania) and the recently affected epidemic areas (Uganda) of eastern Africa was studied. Five cassava varieties; Albert, Colombian, Ebwanateraka, TMS60444 (all susceptible) and Kiroba (tolerant) were graft inoculated with each isolate. Based on a number of parameters including the severity of leaf and root symptoms, and the extent of virus transmission by grafting, the viruses were classified as either severe or relatively mild. These results were further confirmed by the mechanical inoculation of 13 herbaceous hosts in which the virulent isolates caused plant death in Nicotiana clevelandii and N. benthamiana whereas the milder isolates did not. Phylogenetic analysis of complete coat protein gene sequences of these isolates together with sequences obtained from 14 other field-collected samples from Kenya and Zanzibar, and reference sequences grouped them into two distinct clusters, representing the two species of cassava brown streak viruses. Put together, these results did not suggest the association of a hypervirulent form of the virus with the current CBSD epidemic in Uganda. Identification of the severe and milder isolates, however, has further implications for disease management and quarantine requirements.

Mohammed, I. U.; Abarshi, M. M.; Muli, B.; Hillocks, R. J.; Maruthi, M. N.

2012-01-01

197

Institutional Research in Emerging Countries of Southern Africa, Latin America, and the Middle East and North Africa: Global Frameworks and Local Practices  

ERIC Educational Resources Information Center

This chapter presents a synthesis of the conceptualization and practice of institutional research (IR) in higher education (HE) in emerging countries across Southern Africa, Latin America and the Middle East and North Africa (MENA) regions. The chapter contextualizes the growing need for IR in these regions, identifies problems and challenges…

Lange, Lis; Saavedra, F. Mauricio; Romano, Jeanine

2013-01-01

198

Isotopic composition of waters from Ethiopia and Kenya: Insights into moisture sources for eastern Africa  

Microsoft Academic Search

Oxygen and deuterium isotopic values of meteoric waters from Ethiopia are unusually high when compared to waters from other high-elevation settings in Africa and worldwide. These high values are well documented; however, the climatic processes responsible for the isotopic anomalies in Ethiopian waters have not been thoroughly investigated. We use isotopic data from waters and remote data products to demonstrate

Naomi E. Levin; Edward J. Zipser; Thure E. Cerling

2009-01-01

199

Implications of new early Homo fossils from Ileret, east of Lake Turkana, Kenya  

Microsoft Academic Search

Sites in eastern Africa have shed light on the emergence and early evolution of the genus Homo. The best known early hominin species, H.habilis and H.erectus, have often been interpreted as time-successive segments of a single anagenetic evolutionary lineage. The case for this was strengthened by the discovery of small early Pleistocene hominin crania from Dmanisi in Georgia that apparently

F. Spoor; M. G. Leakey; P. N. Gathogo; F. H. Brown; S. C. Antón; I. McDougall; C. Kiarie; F. K. Manthi; L. N. Leakey

2007-01-01

200

Present situation of echinococcosis in the Middle East and Arabic North Africa.  

PubMed

Echinococcosis is one of the major zoonotic parasitic diseases in the Middle East and Arabic North Africa from Morocco to Egypt. Both cystic and alveolar echinococcosis has been reported from these areas. However, cystic echinococcosis is more prevalent and has been reported from all countries in the Middle East and Arabic North Africa. Alveolar echinococcosis is less prevalent and has been reported only from Iran, Turkey, Iraq and Tunisia. Present situation of echinococcosis in dogs and other definitive hosts, animal intermediate hosts and humans in the Middle East and Arabic North Africa has been reviewed. Echinococcus granulosus is highly prevalent in Iran, Turkey, Iraq, Morocco, Tunisia, and Libya. In the Levant countries, the cystic echinococcosis is also highly endemic. In Oman, it is endemic with low prevalence and a very low level in Cyprus. Various surveys have indicated that hydatid cysts are commonly found in sheep, cattle, goats and camels throughout the Middle East and Arabic North Africa. Sheep are the most infected animals of these regions. Most of studies on human have been focused on surgical reports although several population studies have been performed using serological and imaging techniques. Human cystic echinococcosis (CE) is prevalent in the Middle East and Arabic North Africa. It is hyper endemic in Iran, Turkey, Iraq, Jordan, Morocco, Libya, Tunisia, and Algeria, and endemic in Egypt. Studies on the strain specificities of E. granulosus in the Middle East revealed sheep strain (G1) present in sheep, goats, cattle, camels and humans, and the camel strain (G6) in camels, sheep, cattle as well as humans. Dog/sheep strain seems to be more prevalent in the foregoing regions in documented reports from Iran and Jordan. However, a strain of E. granulosus, which resembles the horse strain (G4) strain, has been reported from Jordan. Strain specifications of E. granulosus in Arabic North Africa showed that sheep/dog strain (G1) have been reported from Tunisia and Libya both from humans and animals. However, in Egypt the human cases reported are of camel/dog strain. PMID:16337429

Sadjjadi, Seyed Mahmoud

2006-01-01

201

Comparisons between the rift systems of East Africa, Earth and Beta Regio, Venus  

NASA Astrophysics Data System (ADS)

The rift systems of southern East Africa and Beta Regio, Venus are similar in a number of ways. The rifted East African and Venusian lithospheres have effective elastic thicknesses of ˜ 30 km, suggesting that both lithospheres maintain significant flexural strength during rifting. Both rift systems have maximum fault segment lengths of ˜ 100 km. The effective elastic thickness and maximum fault segment length of both rifts are greater than those seen in many other active extensional regions on Earth, despite the high surface temperatures on Venus. We suggest that the southern East African and Venusian elastic thicknesses and maximum fault segment lengths are due to stronger lithosphere. The rift systems differ in the maximum width of their half graben. East African half grabens are up to ˜ 50 km wide, whilst those on Venus are up to ˜ 150 km wide. To support the topography associated with such half grabens requires shear stresses to act on the bounding faults. In East Africa the greater elastic thickness (compared to most other terrestrial extensional regions) means that wide half grabens can form without requiring the shear stresses acting on the bounding faults to be greater than the ˜ 1-10 MPa (10-100 bars) stress drop typically seen in earthquakes. However, on Venus the absence of sediment infill, greater widths and larger effective topographic steps of the half grabens require shear stresses of up to ˜ 80 MPa (800 bars) to act on the bounding faults. This difference is significant; Venusian faults must be stronger than those on Earth.

Foster, Adrian; Nimmo, Francis

1996-09-01

202

Climate change as a draw bridge between Africa and the Middle East  

NASA Astrophysics Data System (ADS)

Since the very beginning of the human race, the Middle East served as a bridge between Africa-where our species first evolved-and the rest of the world. The passage over this bridge opened and closed with the global fluctuations of climate. The first glacial periods at the beginning of the Quaternary caused the greenhouse of equatorial Africa to become less hospitable, while making the desert belt of the Middle East more humid, green, and thus passable. Flint tools found along the shores of dried up lakes and swamps in the Negev Desert provide evidence that members of the first wave, Homo erectus, as well as the last wave, Homo sapiens, camped there en route to all the other continents.

Issar, Arie S.

2010-07-01

203

Characterising and quantifying vegetative drought in East Africa using fuzzy modelling and NDVI data  

Microsoft Academic Search

This study aims at improving the characterisation and quantification of vegetative drought as a vague spatial phenomenon. 10-day NOAA-AVHRR NDVI images of East Africa from September 2005 to April 2006 are used. Vegetative drought is characterised using a membership function to model the gradual transition between drought and non-drought classes. Measures are implemented to quantify the areas and vagueness of

Coco M. Rulinda; Arta Dilo; Wietske Bijker; Alfred Stein

2012-01-01

204

Beyond the desertification narrative: a framework for agricultural drought in semi-arid East Africa  

Microsoft Academic Search

In the 20th century, much research was done on desertification. Desertification developed into a complex and vague construct that means land degradation under specific conditions. Projects focusing on land degradation in semiarid East Africa have met with limited success because farmers prioritize drought as the major productivity-reducing problem. Yet studies on long-term rainfall trends have not confirmed that droughts are

Monique F. W. Slegers; Leo Stroosnijder

2008-01-01

205

Climate change, water resources, and the politics of adaptation in the Middle East and North Africa  

Microsoft Academic Search

Through an examination of global climate change models combined with hydrological data on deteriorating water quality in the\\u000a Middle East and North Africa (MENA), we elucidate the ways in which the MENA countries are vulnerable to climate-induced impacts\\u000a on water resources. Adaptive governance strategies, however, remain a low priority for political leaderships in the MENA region.\\u000a To date, most MENA

Jeannie Sowers; Avner Vengosh; Erika Weinthal

2011-01-01

206

Seasonal drought forecast system for food-insecure regions of East Africa  

NASA Astrophysics Data System (ADS)

In East Africa, agriculture is mostly rainfed and hence sensitive to interannual rainfall variability, and the increasing food and water demands of a growing population place further stresses on the water resources of this region. Skillful seasonal agricultural drought forecasts for this region can inform timely water and agricultural management decisions, support the proper allocation of the region's water resources, and help mitigate socio-economic losses. Here we describe the development and implementation of a seasonal drought forecast system that is being used for providing seasonal outlooks of agricultural drought in East Africa. We present a test case of the evaluation and applicability of this system for March-April-May growing season over equatorial East Africa (latitude 20 south to 80 North and 360 E to 460E) that encompasses one of the most food insecure and climatically and socio-economically vulnerable regions in East Africa. This region experienced famine as recently as in 2011. The system described here combines advanced satellite and re-analysis as well as station-based long term and real-time observations (e.g. NASA's TRMM, Infra-red remote sensing, Climate Forecast System Reanalysis), state-of-the-art dynamical climate forecast system (NCEP's Climate Forecast System Verison-2) and large scale land surface models (e.g. Variable Infiltration Capacity, NASA's Land Information System) to provide forecasts of seasonal rainfall, soil moisture and Water Requirement Satisfaction Index (WRSI) throughout the season - with an emphasis on times when water is the most critical: start of season/planting and the mid-season/crop reproductive phase. Based on the hindcast assessment of this system, we demonstrate the value of this approach to the US Agency for International Development (USAID)'s efforts to mitigate future losses of lives and economic losses by allowing a proactive approach of drought management that includes early warning and timely action.

Shukla, Shraddhanand; McNally, Amy; Husak, Greg; Funk, Chris

2014-05-01

207

Some important fermented foods of Mid-Asia, the Middle East, and Africa  

Microsoft Academic Search

Other speakers in this Symposium discussed fermented foods of China, Japan, and Southeast Asia; I will describe several other\\u000a fermented foods that are very important in Mid-Asia, the Middle East, and Africa. These fermentations, unlike those of the\\u000a Orient, use bacteria and yeasts instead of filamentous fungi. They are acid products prepared from cereals traditionally grown\\u000a in the areas, notably

C. W. Hesseltine

1979-01-01

208

Assessment of undiscovered oil and gas resources of four East Africa Geologic Provinces  

USGS Publications Warehouse

Four geologic provinces along the east coast of Africa recently were assessed for undiscovered, technically recoverable oil, natural gas, and natural gas liquids resources as part of the U.S. Geological Survey's (USGS) World Oil and Gas Assessment. Using a geology-based assessment methodology, the USGS estimated mean volumes of 27.6 billion barrels of oil, 441.1 trillion cubic feet of natural gas, and 13.77 billion barrels of natural gas liquids.

Brownfield, Michael E.; Schenk, Christopher J.; Charpentier, Ronald R.; Klett, Timothy R.; Cook, Troy A.; Pollastro, Richard M.; Tennyson, Marilyn E.

2012-01-01

209

Poverty, Inequality and Growth in Selected Middle East and North Africa Countries, 1980–2000  

Microsoft Academic Search

This paper uses crosscountry data and country-case studies to analyze trends in poverty, inequality and economic growth in the Middle East and North Africa (MENA) region. Compared to other regions, the MENA region has a low incidence of poverty and income inequality. Two factors account for this situation: international migration\\/remittances and public sector (government) employment. Since the early 1980s international

Richard Adams Jr.; John Page

2003-01-01

210

STS-55 Earth observation of Lake Natron, Tanzania, East Africa  

NASA Technical Reports Server (NTRS)

STS-55 Earth observation taken aboard Columbia, Orbiter Vehicle (OV) 102, shows Lake Natron in Tansania, in the 35-mile-wide East African Rift Valley. This lake is surrounded by sodium carbonate volcanoes. Through erosion, these salts of volcanic origin are transported into the rift valley lakes. The various shades of bright red reflecting from the lake result from the water chemistry and biotic blooms. The white spots in the lakebed are drying soda salts. The depth and circulation of the water in the southern end of the lake cause it to appear dark blue rather than bright red. In the repeated photographs of this lake from orbit, we have seen the extent and intensity of its colors fluctuate seasonally. In this photograph, the biotic activity appears to be at a peak. Such a large extent of red-colored water was not present in the photos taken from STS-56, just a few days before (04-10-93).

1993-01-01

211

Grid search modeling of receiver functions: Implications for crustal structure in the Middle East and North Africa  

Microsoft Academic Search

A grid search is used to estimate average crustal thickness and shear wave velocity structure beneath 12 three-component broadband seismic stations in the Middle East, North Africa, and nearby regions. The crustal thickness in these regions is found to vary from a minimum of 8.0+\\/-1.5km in East Africa (Afar) region to possibly a maximum of 64+\\/-4.8km in the lesser Caucasus.

Eric Sandvol; Dogan Seber; Alexander Calvert; Muawia Barazangi

1998-01-01

212

Examining the impact of climate change and variability on sweet potatoes in East Africa  

NASA Astrophysics Data System (ADS)

Climate change is one of the biggest challenges to food security for the rapidly increasing population of East Africa. Rainfall is becoming more variable and temperatures are rising, consequently leading to increased occurrence of droughts and floods, and, changes in the timing and length of growing seasons. These changes have serious implications on crop production with the greatest impact likely to be on C4 crops such as cereals compared to C3 crops such as root tubers. Sweet potatoes is one the four most important food crops in East Africa owing to its high nutrition and calorie content, and, high tolerance to heat and drought, but little is known about how the crop will be affected by climate change. This study identifies the major climatic constraints to sweet potato production and examines the impact of projected future climates on sweet potato production in East Africa during the next 10 to 30 years. A process-based Sweet POTato COMputer Simulation (SPOTCOMS) model is used to assess four sweet potato cultivars; Naspot 1, Naspot 10, Naspot 11 and SPK 004-Ejumula. This is work in progress but preliminary results from the crop modeling experiments and the strength and weakness of the crop model will be presented.

Ddumba, S. D.; Andresen, J.; Moore, N. J.; Olson, J.; Snapp, S.; Winkler, J. A.

2013-12-01

213

Water Uses and Children's Lives in East Africa. Water in Africa.  

ERIC Educational Resources Information Center

The Water in Africa Project was realized over a 2-year period by a team of Peace Corps volunteers, World Wise Schools (WWS) classroom teachers, and WWS staff members. As part of an expanded, detailed design, resources were collected from over 90 volunteers serving in African countries, photos and stories were prepared, and standards-based learning…

Maher, Robert

214

P-wave tomography reveals a westward dipping low velocity zone beneath the Kenya Rift  

NASA Astrophysics Data System (ADS)

Three teleseismic P-wave travel time data sets (KRISP 1985, 1989-1990 Kenya Broadband Seismic Experiment) have been inverted to obtain a new tomographic model of the upper mantle beneath the Kenya Rift. The model shows a 0.5-1.5% low velocity anomaly below the rift extending to about 150 km depth. Below ~150 km depth, the anomaly broadens to the west toward the Tanzania Craton, suggesting a westward dip to the structure. Tomographic images to the south in Tanzania and to the north in Ethiopia also show westward dipping low velocity anomalies below depths of ~150-200 km. The presence of westward dipping low velocity structures along much of the East African rift (Ethiopia, Kenya and Tanzania) is difficult to explain with a plume model and is consistent with some models of the African Superplume showing anomalous lower and upper mantle structure connecting at mid-mantle depths under the western side of East Africa.

Park, Yongcheol; Nyblade, Andrew A.

2006-04-01

215

An Observational Study of the Relationship between Excessively Strong Short Rains in Coastal East Africa and Indian Ocean SST  

Microsoft Academic Search

Composites of SST, wind, rainfall, and humidity have been constructed for years of high rainfall during September, October, and November (SON) in equatorial and southern-central East Africa. These show that extreme East African short rains are associated with large-scale SST anomalies in the Indian Ocean that closely resemble those that develop during Indian Ocean dipole or zonal mode (IOZM) events.

Emily Black; Julia Slingo; Kenneth R. Sperber

2003-01-01

216

Analogy between natural gas found in lakes of rift valley system of east Africa and its allied gas in Japan  

Microsoft Academic Search

The Afar triangle in northeastern Ethiopia is where the Red Sea rift, the Carlsberg Ridge of the Indian Ocean, and the Rift Valley system of east Africa meet. In 1979, J. Welhan and H. Craig reported that hydrothermal vents at 21°N, on the East Pacific Rise, are discharging turbid waters. Mixtures of the plumes with ambient seawater contain significant amounts

Osamu Fukuta

1984-01-01

217

Are Staple Foods Becoming More Expensive For Urban Consumers In Eastern And Southern Africa? Trends in Food Prices, Marketing Margins, and Wage Rates in Kenya, Malawi, Mozambique, and Zambia  

Microsoft Academic Search

The world food and financial crises threaten to undermine the real incomes of urban consumers in eastern and southern Africa. This study investigates patterns in staple food prices, wage rates, and marketing margins for urban consumers in Kenya, Malawi, Mozambique, and Zambia between 1993 and 2009. There is high correlation among wage rate series for various government and private sector

Nicole M. Mason; Thomas S. Jayne; Cynthia Donovan; Antony Chapoto

2009-01-01

218

Environmental Mainstreaming in Development Policy and Planning in Sub-Saharan Africa: A Case Study from Kenya  

Microsoft Academic Search

\\u000a The paper aims to map Kenya’s national development planning framework, investigate any environmental (including climate change)\\u000a mainstreaming (EM) strategies employed, and identify the prospects and challenges for EM furtherance. The country’s heavy\\u000a reliance on environment and natural resources for socio-economic development makes it particularly vulnerable to climate change.\\u000a Effective EM will thus ensure better resource management and utilisation, improve livelihoods

Martin Ochieng Oulu; Emmanuel Kwesi Boon

219

Spatial variation of primordial 3-He in crustal fluids along the East-African Rift system (the Ethiopian and the Kenya Rift section)  

NASA Technical Reports Server (NTRS)

(3)He/(4)He compositions are presented for groundwater samples from the Ethiopian segment of the East-Afrikan Rift and from its northern extension, the adjacent Afar region (Djibuti). Helium isotope data are compared to those obtained previously from the Gregory Rift, south of Ethiopia. The distribution pattern of mantle-derived volatiles along the entire East-African-Rift (-from south Kenya to Djibuti-) is discussed and their sources are identified. Helium isotope ratios (R) for samples from the Ethiopian part of the Rift range from 6.3 to 16.0 times the atmospheric ratio (Ra=1.4 x 10(exp -6) and thus show together with a MOR component a considerable hotspot helium component. These mantle helium concentrations are comparable to those observed in groundwaters and volcanic rocks from the Afar plume region in Djibuti. Here R/Ra values range from 9 to 13 times the atmospheric composition, with mantle-derived helium concentrations being higher than at spreading ocean ridges. R/Ra values from Ethiopia and Djibuti are entirely different from those observed in groundwaters at the southerly extending Gregory Rift in Kenya, where R/Ra values scatter between 0.5 and 6. At the northernmost part of the Gregory Rift, close to Ethiopia mantle helium contents are slightly higher, with R/Ra-values varying between 6.5 and 8.0.

Griesshaber, E.; Weise, S.; Darling, G.

1994-01-01

220

Determinants of Rural Poverty in Africa: The Case of Small Holder Farmers in Kenya  

NASA Astrophysics Data System (ADS)

Sub-Saharan Africa is likely to hold large numbers of very poor rural people in the near future unless sustainable intervention measures are undertaken. Although both history and theory point to the important role of agriculture in poverty reduction, such growth today faces even more difficulties. This study uses a probit model on a sample of 600 smallholder farmers to establish factors that influence probability of households= escaping chronic poverty. Results show that access to micro-credit, education, participation in agricultural seminars, livestock assets and location in high potential areas significantly influence the probability of households exiting chronic poverty. On the other hand, female gender and distance to the market increases the probability of persistence in chronic poverty. Present findings reveal that micro-credit access, gender, education and market access are key determinants of exit from rural poverty. Therefore through intensified micro-credit provision, education, women empowerment via legal rights to property and improvement of rural access roads, the poverty status could be ameliorated.

Owuor, G.; Ngigi, M.; Ouma, A. S.; Birachi, E. A.

221

Genetic evidence for complexity in ethnic differentiation and history in East Africa.  

PubMed

The Afro-Asiatic and Nilo-Saharan language families come into contact in Western Ethiopia. Ethnic diversity is particularly high in the South, where the Nilo-Saharan Nyangatom and the Afro-Asiatic Daasanach dwell. Despite their linguistic differentiation, both populations rely on a similar agripastoralist mode of subsistence. Analysis of mitochondrial DNA extracted from Nyangatom and Daasanach archival sera revealed high levels of diversity, with most sequences belonging to the L haplogroups, the basal branches of the mitochondrial phylogeny. However, in sharp contrast with other Ethiopian populations, only 5% of the Nyangatom and Daasanach sequences belong to haplogroups M and N. The Nyangatom and Daasanach were found to be significantly differentiated, while each of them displays close affinities with some Tanzanian populations. The strong genetic structure found over East Africa was neither associated with geography nor with language, a result confirmed by the analysis of 6711 HVS-I sequences of 136 populations mainly from Africa. Processes of migration, language shift and group absorption are documented by linguists and ethnographers for the Nyangatom and Daasanach, thus pointing to the probably transient and plastic nature of these ethnic groups. These processes, associated with periods of isolation, could explain the high diversity and strong genetic structure found in East Africa. PMID:19706029

Poloni, Estella S; Naciri, Yamama; Bucho, Rute; Niba, Régine; Kervaire, Barbara; Excoffier, Laurent; Langaney, André; Sanchez-Mazas, Alicia

2009-11-01

222

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

PubMed Central

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 both their propensity to exchange components and the absence of recombination with non-CMG begomoviruses. Our results suggest an important role of anthropic factors in CMGs spread as the principal axes of viral migration correspond with major routes of human movement and commercial trade. Finer-scale temporal analyses of CMGs to precisely scale the relative contributions of human and insect transmission to their movement dynamics will require further extensive sampling in the SWIO region.

2012-01-01

223

Sunspots, El Niño, and the levels of Lake Victoria, East Africa  

NASA Astrophysics Data System (ADS)

An association of high sunspot numbers with rises in the level of Lake Victoria, East Africa, has been the focus of many investigations and vigorous debate during the last century. In this paper, we show that peaks in the ~11-year sunspot cycle were accompanied by Victoria level maxima throughout the 20th century, due to the occurrence of positive rainfall anomalies ~1 year before solar maxima. Similar patterns also occurred in at least five other East African lakes, which indicates that these sunspot-rainfall relationships were broadly regional in scale. Although irradiance fluctuations associated with the sunspot cycle are weak, their effects on tropical rainfall could be amplified through interactions with sea surface temperatures and atmospheric circulation systems, including ENSO. If this Sun-rainfall relationship persists in the future, then sunspot cycles can be used for long-term prediction of precipitation anomalies and associated outbreaks of insect-borne disease in much of East Africa. In that case, unusually wet rainy seasons and Rift Valley Fever epidemics should occur a year or so before the next solar maximum, which is expected to occur in 2011-2012 AD.

Stager, J. Curt; Ruzmaikin, Alexander; Conway, Declan; Verburg, Piet; Mason, Peter J.

2007-08-01

224

Policies on Free Primary and Secondary Education in East Africa: A Review of the Literature. Create Pathways to Access. Research Monograph No. 10  

ERIC Educational Resources Information Center

Kenya, Tanzania and Uganda are among the countries in Sub-Saharan Africa which have recently implemented policies for free primary education, motivated in part by renewed democratic accountability following the re-emergence of multi-party politics in the 1990s. However, it is not the first time that the goal of expanding primary education has been…

Oketch, Moses O.; Rolleston, Caine M.

2007-01-01

225

HIV Surveillance and Epidemic Profile in the Middle East and North Africa  

PubMed Central

Summary HIV infection is the most devastating infection that has emerged in the recent history. The risk of being infected can be associated with both individual’s knowledge and behavior and community vulnerability influenced by cultural norms, laws, politics, and social practices. Despite that the countries in the Middle East and North Africa have succeeded in keeping low the HIV epidemic rates, the number of identified infected cases are increasing. Since the appearance of the first AIDS cases, all the national authorities devoted their efforts to abort the epidemic in its early stages. The rate of new HIV infections across the Middle East and North Africa region are not at an alarming level, but the need for a concerted effort from nation-states and nongovernmental organizations to stem the spread of the virus across the region is vital. Most countries of the region have put in place better information systems to track the HIV epidemic, yet the passive HIV/AIDS reporting remains the cornerstone in the HIV surveillance systems. Several countries still believe that their current strategies are optimal to the HIV status within their territories and that their national strategies are appropriate to their low epidemic status that is not expected to grow. Additionally, these countries fear that establishing an HIV national program to survey risk behaviors may be perceived as an approval of these behaviors that are culturally and religiously unacceptable. This background article aims to summarize the HIV surveillance strategies and epidemic profile in 17 Arab countries in the Middle East and North Africa. The article, also, displays the national surveillance system and the epidemic profile in Egypt and Lebanon as models for the region. This information aims to provide useful insights that may help the national authorities in finding out the best surveillance strategies that allow merging and collecting biological and risk data which is an integral part of their efforts to fight the HIV epidemic in the region.

Shawky, Sherine; Soliman, Cherif; Kassak, Kassem M.; Oraby, Doaa; El-Khoury, Danielle; Kabore, Inoussa

2011-01-01

226

World Directory of Energy Information. Volume 2: Middle East, Africa and Asia/Pacific  

SciTech Connect

Volume 2 of the four-part Directory includes a detailed review of energy resource development of 64 countries, 15 of which are in the Middle East, 30 in Africa, and 19 in the Asia and Pacific area. The volume is divided into four parts: (1) International Framework; (2) Country Reviews; (3) Energy Organizations; and (4) Energy Publications. The organizations and publications information covers both international and by country. Three indices list publications alphabetically, by subject and country, and publishing bodies. 6 figures, 2 tables. (DCK)

Not Available

1982-01-01

227

What it costs to work expats in Mid East/North Africa  

SciTech Connect

The costs of expatriates stationed in the Middle East and North Africa with U.S. oil and service companies are high. The benefits programs that these companies must offer to recruit American expatriates have raised overhead costs and lowered profit margins in relation to European competitors. This article outlines the costs of sending an employee to this area of the world, suggests ways to minimize these costs, and details the various benefits programs both U.S. and European companies are currently offering. In conclusion, the employment policy trends that these high costs are causing are reviewed.

Jacobs, P.A.

1983-03-01

228

A survey of Simulium control in Africa  

PubMed Central

It has become possible to control or even eradicate the Simulium fly vectors of Onchocerca volvulus, the causative organism of onchocerciasis. There are two vectors in Africa—namely, S. damnosum, characteristic of the rivers of West Africa, and S. neavei, which breeds on the carapaces of crabs in the streams of East Africa. The use of DDT applied to the water at a concentration as low as 0.1 p.p.m. for 30 minutes eliminates the larvae of Simulium. Such larvicidal methods have eradicated S. neavei from western Kenya and virtually eradicated S. damnosum from the Victoria Nile in Uganda. Excellent control sufficient to render the transmission of onchocerciasis almost negligible has been obtained at Léopoldville (Republic of the Congo) and in circumscribed areas in southern Chad, Northern Nigeria, and Sierra Leone. The following survey describes operational research on Simulium control carried out in Kenya, Uganda, the Congo, Chad, Nigeria, Ghana, Upper Volta and Sierra Leone.

Brown, A. W. A.

1962-01-01

229

Correlation of Pliocene and Pleistocene tephra layers between the Turkana Basin of East Africa and the Gulf of Aden  

USGS Publications Warehouse

Electron-microprobe analyses of glass shards from volcanic ash in Pliocene and Pleistocene deep-sea sediments in the Gulf of Aden and the Somali Basin demonstrate that most of the tephra layers correlate with tephra layers known on land in the Turkana Basin of northern Kenya and southern Ethiopia. Previous correlations are reviewed, and new correlations proposed. Together these data provide correlations between the deep-sea cores, and to the land-based sections at eight levels ranging in age from about 4 to 0.7 Ma. Specifically, we correlate the Moiti Tuff (???4.1 Ma) with a tephra layer at 188.6 m depth in DSDP hole 231 and with a tephra layer at 150 m depth in DSDP hole 241, the Wargolo Tuff with a tephra layer at 179.7 m in DSDP Hole 231 and with a tephra layer at 155.3 m depth in DSDP Hole 232, the Lomogol Tuff (defined here) with a tephra layer at 165 m in DSDP Hole 232A, the Lokochot Tuff with a tephra layer at 140.1 m depth in DSDP Hole 232, the Tulu Bor Tuff with a tephra layer at 160.8 m depth in DSDP Hole 231, the Kokiselei Tuff with a tephra layer at 120 m depth in DSDP Hole 231 and with a tephra layer at 90.3 m depth in DSDP Hole 232, the Silbo Tuff (0.74 Ma) with a tephra layer at 35.5 m depth in DSDP Hole 231 and possibly with a tephra layer at 10.9 m depth in DSDP Hole 241. We also present analyses of other tephra from the deep sea cores for which correlative units on land are not yet known. The correlated tephra layers provide eight chronostratigraphic horizons that make it possible to temporally correlate paleoecological and paleoclimatic data between the terrestrial and deep-sea sites. Such correlations may make it possible to interpret faunal evolution in the Lake Turkana basin and other sites in East Africa within a broader regional or global paleoclimatic context. ?? 1992.

Brown, F. H.; Sarna-Wojcicki, A. M.; Meyer, C. E.; Haileab, B.

1992-01-01

230

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

PubMed

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. PMID:24223262

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

2013-09-01

231

High Resolution Population Maps for Low Income Nations: Combining Land Cover and Census in East Africa  

PubMed Central

Background Between 2005 and 2050, the human population is forecast to grow by 2.7 billion, with the vast majority of this growth occurring in low income countries. This growth is likely to have significant social, economic and environmental impacts, and make the achievement of international development goals more difficult. The measurement, monitoring and potential mitigation of these impacts require high resolution, contemporary data on human population distributions. In low income countries, however, where the changes will be concentrated, the least information on the distribution of population exists. In this paper we investigate whether satellite imagery in combination with land cover information and census data can be used to create inexpensive, high resolution and easily-updatable settlement and population distribution maps over large areas. Methodology/Principal Findings We examine various approaches for the production of maps of the East African region (Kenya, Uganda, Burundi, Rwanda and Tanzania) and where fine resolution census data exists, test the accuracies of map production approaches and existing population distribution products. The results show that combining high resolution census, settlement and land cover information is important in producing accurate population distribution maps. Conclusions We find that this semi-automated population distribution mapping at unprecedented spatial resolution produces more accurate results than existing products and can be undertaken for as little as $0.01 per km2. The resulting population maps are a product of the Malaria Atlas Project (MAP: http://www.map.ox.ac.uk) and are freely available.

Tatem, Andrew J.; Noor, Abdisalan M.; von Hagen, Craig; Di Gregorio, Antonio; Hay, Simon I.

2007-01-01

232

Temporal Changes in Lead Depositions in East Africa: A Case Study of Lake Tanganyika  

NASA Astrophysics Data System (ADS)

Environmental changes (e.g., increasing rates of soil erosion) in East Africa have been attributed to local human activities and global climate change. However, reports on the impacts of these changes on the remobilization and transport of heavy metals, such as lead, in the environment are presently limited in literature. Therefore, this study was designed to chronicle the historic transport and deposition of lead in East Africa as recorded in the sediments of Lake Tanganyika. Sediment cores collected from regions with varying anthropogenic impacts of Lake Tanganyika were divided into sections, dated using excess lead-210, and analyzed for lead concentrations and isotopic composition. The results show that the amount of lead deposited in some regions of the lake increased recently (e.g., by more than 25% over the past two decades preceding 2000) which is consistent with regional changes in sediment accumulation rates in Lake Tanganyika. Temporal changes in the sources of that lead are being characterized by their isotopic compositions.

Odigie, K. O.; Flegal, A. R.

2011-12-01

233

Status report of propagation models: Middle East and North Africa (S5.3)  

SciTech Connect

An improved understanding of the influence that tectonic structure has on regional seismic phases is needed to improve the current performance of regional discriminants and their transportability to the Middle East and North Africa. In the case that the crustal structure can be approximated by a flat layered laterally invariant medium, layer-cake reflectivity modeling can be used to obtain an accurate representation of regional phases. However, a laterally heterogeneous crust is just as common as a layered cake structure and in this case large variations in regional phase amplitudes are not uncommon. For instance, it has been shown that rough surface topography and undulations in the Moho can cause the transfer of energy between various surface wave modes and between surface waves and body waves greatly increasing the potential variability of seismic phases. Larger scale structure such as thickening or thinning of the crust can also greatly affect phase propagation. In some instances, changes between different tectonic regions such as that which occurs at a continental-oceanic boundary can completely block phases such as Lg rendering certain discriminants useless. In addition to structure along the path, lateral structure and free surface topography near the source and receiver can cause complex scattering effects with strong directional, frequency, and near-field effects. Given that the Middle East and North Africa cross many different tectonic boundaries, the authors are using numerical propagation models to understand how the relevant tectonic features affect the propagation of primary discriminant phases.

Schultz, C.A.; Patton, H.J.; Goldstein, P. [Lawrence Livermore National Lab., CA (United States). Earth Sciences Div.

1995-11-01

234

A proposed drainage evolution model for Central Africa—Did the Congo flow east?  

NASA Astrophysics Data System (ADS)

Understanding the origin of Sub-Saharan biodiversity requires knowing the history of the region's paleo-ecosystems. As water is essential for sustaining of life, the evolving geometry of river basins often have influence on local speciation. With this in mind, we analyse drainage patterns in Central and East Africa. Evidence from marine fossils suggests the Congo Basin was submerged for much of the Cretaceous, and after being uplifted drained eastwards through a paleo-Congo river towards the Indian Ocean. Two remnant peneplains in the Congo Basin are interpreted as evidence that this basin was tectonically stable on at least two occasions in the past. The lower peneplain is interpreted as the base level of the drainage pattern that had its outlet in Tanzania, at the present Rufiji Delta that was once over 500 km wide. The Luangwa, today a tributary of the Zambezi river, was a part of this drainage network. This pattern was subsequently disrupted by uplift associated with the East African Rifting in the Oligocene-Eocene (30-40 Ma). The resulting landlocked system was captured in the Miocene (5-15 Ma) by short rivers draining into the Atlantic Ocean, producing the drainage pattern of Central Africa seen today.

Stankiewicz, Jacek; de Wit, Maarten J.

2006-01-01

235

A literature review: the role of the private sector in the production of nurses in India, Kenya, South Africa and Thailand  

PubMed Central

Background The demand for nurses is growing and has not yet been met in most developing countries, including India, Kenya, South Africa, and Thailand. Efforts to increase the capacity for production of professional nurses, equitable distribution and better retention have been given high strategic priority. This study examines the supply of, demand for, and policy environment of private nurse production in four selected countries. Methods A scoping systematic review was undertaken to assess the evidence for the role of private sector involvement in the production of nurses in India, Kenya, South Africa, and Thailand. An electronic database search was performed, and grey literature was also captured from the websites of Human Resources for Health (HRH)-related organizations and networks. The articles were reviewed and selected according to relevancy. Results The review found that despite very different ratios of nurses to population ratios and differing degrees of international migration, there was a nursing shortage in all four countries which were struggling to meet growing demand. All four countries saw the private sector play an increasing role in nurse production. Policy responses varied from modifying regulation and accreditation schemes in Thailand, to easing regulation to speed up nurse production and recruitment in India. There were concerns about the quality of nurses being produced in private institutions. Conclusion Strategies must be devised to ensure that private nursing graduates serve public health needs of their populations. There must be policy coherence between producing nurses for export and ensuring sufficient supply to meet domestic needs, in particular in under-served areas. This study points to the need for further research in particular assessing the contributions made by the private sector to nurse production, and to examine the variance in quality of nurses produced.

2013-01-01

236

The Earliest Hominid Migration out of Africa and Near East Colonization  

NASA Astrophysics Data System (ADS)

It is generally accepted that Central East Africa was the springboard for hominid evolution in the latest Miocene or Early Pliocene. However the timing and pathways of migrations from Africa to Eurasia are still debatable. The only certain land bridge and main route between Africa and Eurasia since the Late Pliocene-Early Pleistocene is the Levantine Corridor. This is evident in some of the most ancient remains of early hominids and tools outside Africa in the Middle East. The study of Lower Paleolithic sites in this region and in the neighboring area sheds some light on several potential migration and colonization events. The determination of ages of the prehistoric sites is crucial for any study of early human migration events, but it is also the most difficult data to recover. The typo-technological studies yield only relative age, and so do sequences of raised Pleistocene beaches, marine deposits, river terraces and paleo-lake formations. The scarcity of volcanic ash deposits excludes radiometric dating. Israel located at the Levantine Corridor yields a wealth of prehistoric findings and sites. We combine paleomagnetic and thermoluminescence measurements as dating tools. This new combination yields high quality, surprising results. Several preliminary paleomagnetic studies of lake deposits, cave deposits and soil sequences in well known sites in Israel such as the Erk-El Ahmar formation, and the Lower Paleolithic Tabun Cave in Mount Carmel, the Evron Quarry in northern Israel, and Rochama site in southern Israel. We conclude that the part of Erk-El-Ahmar Formation, which bears core-choppers and flakes, identified as typical Oldowan tools were deposited about 1.7-2.0 Ma. We found that the Rochama and Evron sites are located in soil sequences, several meters below the 0.78 Ma Brunhes-Matuyama boundary. Based on continuous soil accumulation rates and pedogenesis processes the age of these sites is about 1 Ma. This new data provides the first constraint for the 1 Ma and older hominid colonization along the Levantine Corridor, offering a glimpse at the first journey out of Africa.

Ron, H.; Levi, S.; Porat, N.

2001-12-01

237

Clampdown on AIDS information in E. Africa.  

PubMed

What is most alarming about Acquired Immune Deficiency Syndrome (AIDS) in East Africa is that it is taboo. The reason for the clamping down on publicity in Kenya is that the government sees AIDS as a killer of tourism, the country's 2nd largest revenue earner. The government of Kenya, like several other African governments, is reacting to the widespread belief in the West that AIDS originated in Africa and that it is rampant in Central and East Africa. These "facts" have yet to be proven conclusively by medical evidence. It is certain that a large percentage of the population of these regions have antibodies to the virus HTLV-III, which causes AIDS. From this, virologists deduce that the people concerned must have been exposed to the AIDS virus. The Western media has exaggerated the African AIDS connection and given the impression that African countries are gripped in raging AIDS epidemics. In response to the alarmist publicity, some African countries have clamped down in information about the disease. The result is that the Western press feels confirmed in its fears and the local population, depending on rumor and heresay, have been living in a state of absolute panic. Instead of allaying fears, the clampdown on news has fueled dangerous rumors at home and frightened away tourists. Whatever may be causing the disease and wherever it may have come from, there is no question at all that there are now confirmed cases of AIDS in East and Central Africa. Thus far, the number of confirmed cases if relatively small, but if governments continue to try and hide the facts from the public, there is a real danger of an epidemic developing. A ministerial statement admits to 7 confirmed AIDS cases in Kenya. There are discrepancies in the reports, however. Doctors interviewed by "New African" in Nairobi recently believe the situation is far more serious than the government admits. Doctors in Kenya make the point that the country is highly vulnerable to the spread of AIDS, particularly as it is known to be transmitted in heterosexual as well as homosexual relationships. Medical experts in Kenya identify the need for an AIDS Researh Foundation to be set up to encompass the whole of the East Africa region. This center would receive and collate information on AIDS from Tanzania, Uganda, and Kenya, assess it, carry out clinical research, study and experiment with anti-AIDS compounds, and formulate a public education program to be disseminated by the media. 2 points need to be known: it is difficult to contract AIDS casually; through blood and semen, carriers of the virus can transmit AIDS like wildfire creating an epidemic. PMID:12314088

Hitchcock, B

1986-01-01

238

The contribution of increased incoming shortwave radiation to the retreat of the Rwenzori Glaciers, East Africa, during the 20th century  

Microsoft Academic Search

Based on (i) the observation of spatially differential glacier retreats in the tropical Rwenzori Range (East Africa) during the 20th century, which are most striking on the mountains Baker and Speke, and (ii) the information on an abrupt climate change to drier conditions in East Africa at the end of the 19th century, the following hypothesis is derived: owing to

Thomas Mölg; Christian Georges; Georg Kaser

2003-01-01

239

The Rise and Fall of the Schools Science Project in East Africa.  

ERIC Educational Resources Information Center

Reviews problems associated with implementing the School Science Project (SSP) in Kenya, and the subsequent downfall of the project in the late 1970s. Concludes that the SSP experience raises fundamental questions about secondary science education in Kenya and the rest of the developing world. (BSR)

Lillis, Kevin M.; Lowe, John

1987-01-01

240

High-throughput high-resolution class I HLA genotyping in East Africa.  

PubMed

HLA, the most genetically diverse loci in the human genome, play a crucial role in host-pathogen interaction by mediating innate and adaptive cellular immune responses. A vast number of infectious diseases affect East Africa, including HIV/AIDS, malaria, and tuberculosis, but the HLA genetic diversity in this region remains incompletely described. This is a major obstacle for the design and evaluation of preventive vaccines. Available HLA typing techniques, that provide the 4-digit level resolution needed to interpret immune responses, lack sufficient throughput for large immunoepidemiological studies. Here we present a novel HLA typing assay bridging the gap between high resolution and high throughput. The assay is based on real-time PCR using sequence-specific primers (SSP) and can genotype carriers of the 49 most common East African class I HLA-A, -B, and -C alleles, at the 4-digit level. Using a validation panel of 175 samples from Kampala, Uganda, previously defined by sequence-based typing, the new assay performed with 100% sensitivity and specificity. The assay was also implemented to define the HLA genetic complexity of a previously uncharacterized Tanzanian population, demonstrating its inclusion in the major East African genetic cluster. The availability of genotyping tools with this capacity will be extremely useful in the identification of correlates of immune protection and the evaluation of candidate vaccine efficacy. PMID:20505773

Koehler, Rebecca N; Walsh, Anne M; Sanders-Buell, Eric E; Eller, Leigh Anne; Eller, Michael; Currier, Jeffrey R; Bautista, Christian T; Wabwire-Mangen, Fred; Hoelscher, Michael; Maboko, Leonard; Kim, Jerome; Michael, Nelson L; Robb, Merlin L; McCutchan, Francine E; Kijak, Gustavo H

2010-01-01

241

Two mantle plumes beneath the East African rift system: Sr, Nd and Pb isotope evidence from Kenya Rift basalts  

Microsoft Academic Search

Major and trace element and radiogenic isotope ratios (Sr, Nd and Pb) are presented for a suite of Neogene to Recent basalts (MgO>4 wt%) from the axial regions of the Kenya Rift. Samples have compositions ranging from hypersthene-normative basalt through alkali basalt to basanite and are a subset of a larger database in which compositions extend to nephelinite. A broadly

Nick Rogers; Ray Macdonald; J. Godfrey Fitton; Rhiannon George; Martin Smith; Barbara Barreiro

2000-01-01

242

Improving Agricultural Drought Monitoring in East Africa with Unbiased Rainfall Fields and Detailed Land Surface Physics  

NASA Astrophysics Data System (ADS)

Monitoring drought is particularly challenging within rainfed agricultural and pastoral systems, where it can serve the greatest need. Such locations often have sparse or non-existent ground based measurements of precipitation, evapotranspiration (ET), and soil moisture. For more effective drought monitoring with limited hydroclimate observations, we simulate land surface states using the Community Noah Land Surface Model forced with different merged rainfall products inside a Land Information System (LIS). Using model outputs we will answer the questions: How sensitive are soil moisture and ET fields to differences in rainfall forcing and model physics? What are acceptable drought-specific tradeoffs between near-real time availability and skill of rainfall data? Preliminary results with the African Rainfall Estimation Algorithm Version 2 (RFE2.0) outperformed global products, suggesting that sub-global rainfall estimates are the way forward for regional drought monitoring. Specifically, the Noah model forced with RFE2.0 better resolved the heterogeneous patterns in crop stress than the Famine Early Warning System Network (FEWS NET) operational Water Requirement Satisfaction Index (WRSI) model. To further investigate the improvement in drought monitoring while maintaining timeliness, we unbias (using Africa specific climatology) the precipitation products from CPC Merged Analysis of Precipitation (CMAP), Tropical Rainfall Measurement Mission (TRMM), and RFE2.0. The skill (relative accuracy) and reliability (average agreement) of the unbiased rainfall are calculated against an unbiased precipitation product augmented with station data from Ethiopia and Kenya. Soil moisture and ET fields from Noah are compared to the operational FEWS NET WRSI, soil water anomaly index, and the World Food Program’s Crop and Food Security Assessment Mission reports. We anticipate that the unbiased rainfall fields will improve the accuracy, spatio-temporal resolution, and heterogeneity of the ET and soil moisture estimates compared to current operational drought indicators. Ultimately, these improved information products will better inform decision makers about seasonal food production and help them assess the need for relief, potentially saving millions of lives.

McNally, A.; Yatheendradas, S.; Peters-Lidard, C. D.; Michaelsen, J.

2010-12-01

243

The Quality of Secondary Education in the Middle East and North Africa: What Can We Learn from TIMSS' Results?  

ERIC Educational Resources Information Center

Research on educational quality has been scarce in the Middle East and North Africa (MENA) region, whereas the debates over educational quality date from 1966 in the USA with the Coleman Report. Fortunately TIMSS (Trends in International Mathematics and Science Study) starts to fill this gap by providing data on students' achievement and for many…

Bouhlila, Donia Smaali

2011-01-01

244

A Comprehensive Review of the Status of Early Childhood Development in the Middle East and North Africa.  

ERIC Educational Resources Information Center

This report reviews the status of early childhood education (ECE) programs in UNICEF's Middle East and North Africa region. The report compiles information about ECE programs in 18 countries based on a questionnaire sent to UNICEF country offices and other sources. The introduction sets out the economic and social rationales for investing in early…

Khattab, Mohammad Salih

245

Rainfall Conditions in Equatorial East Africa during the Nineteenth Century as Inferred from the Record of Lake Victoria  

Microsoft Academic Search

The East African lakes have exhibited dramaticfluctuations on both historical and paleo-climatictime scales. Levels of these lakes, and otherhistorical indicators in Africa, suggested thatenvironmental conditions in the nineteenth centurywere much more extreme than anything evident in themodern record. In this study, a water balance modelis used to estimate the rainfall associated with theseconditions, based on the Lake Victoria record. Theresults

Sharon E. Nicholson; Xungang Yin

2001-01-01

246

Internationalization "vs" Regionalization of Higher Education in East Africa and the Challenges of Quality Assurance and Knowledge Production  

ERIC Educational Resources Information Center

Internationalization of higher education in East Africa raises various questions related to its magnitude and intensity, its capacity to address issues of access, equity and regional research and developmental needs. Internationalization and regionalization as processes in higher education can synergize each other but can also limit the success of…

Ogachi, Oanda

2009-01-01

247

An analysis of energy consumption and carbon dioxide emissions in countries of the Middle East and North Africa  

Microsoft Academic Search

In this paper, energy consumption and carbon dioxide emissions from 17 countries of the Middle East and North Africa are studied using Data Envelopment Analysis. Four indicators for the year 1996 are employed in the analysis. The analysis shows that Sudan, Bahrain and Oman are considered efficient, and Saudi Arabia is rated as the least efficient under constant returns to

Ramakrishnan Ramanathan

2005-01-01

248

U.S. Students Study Abroad in the Middle East/North Africa: Factors Influencing Growing Numbers  

ERIC Educational Resources Information Center

The political events of the last decade and the Arab Spring have made it more important than ever for Americans to understand the language, culture, and history of the Middle East/North Africa (MENA) region. Study abroad is one important method that can significantly increase American students' understanding of the Arabic language and the…

Lane-Toomey, Cara K.; Lane, Shannon R.

2013-01-01

249

EFFECTIVENESS OF ISO 14001 ENVIRONMENTAL MANAGEMENT SYSTEMS IN ENHANCING CORPORATE ENVIRONMENTAL SUSTAINABILITY AT UNILEVER SOUTH EAST AFRICA IN HARARE, ZIMBABWE  

Microsoft Academic Search

ISO 14001 environmental management system remained one tool widely implemented to mitigate industry's negative impacts on both aquatic and terrestrial life. However, skepticism still surrounds the worthiness of this tool in environmental management, as it merely sets a framework without stringent measures. The paper seeks to explore the effectiveness of the standard at Unilever South East Africa in improving corporate

Thomas Marambanyika; Timothy Mutekwa

250

Psychology and modern life challenges: The 2nd Middle East and North Africa Regional Conference of Psychology, Amman, Jordan, 2007  

Microsoft Academic Search

The Second Middle East and North Africa Regional Conference of Psychology was held in Amman from 27 April – 1 May 2007 under the Royal Patronage of Her Majesty Queen Rania Al?Abdullah and the auspices of the International Union of Psychological Science, the International Association of Applied Psychology, and the International Association of Cross?Cultural Psychology. It was hosted by the

Michael Knowles; Michel Sabourin

2008-01-01

251

Strategies for Female Education in the Middle East and North Africa. Learning for the 21st Century.  

ERIC Educational Resources Information Center

This paper is designed to assist education planners and policymakers in the Middle East and North Africa (MENA) region to identify a range of strategic options to increase the access and retention of girls in the education system. It provides a review of materials relating to the status of female education in the MENA region, statistical data on…

Rihani, May; Prather, Cynthia J.

252

Girls' Drop-Out from Primary Schooling in the Middle East and North Africa: Challenges and Alternatives.  

ERIC Educational Resources Information Center

The present situation in the Middle East and North Africa Region (MENA) regarding primary school drop-out and repetition, with special reference to the situation of the girl child, is examined in this study. The in-school as well as out-of-school causes of primary school drop-out are examined, and solutions that help reduce or eliminate the…

Mehrah, Golnar

253

Tidal loading along a profile Europe-East Africa-South Asia-Australia and the Pacific Ocean  

Microsoft Academic Search

Precision measurements of earth tides along a profile stretching from Europe to Polynesia through East Africa, Asia and Australia are used to characterize ocean tides in different basins and thus provide a check on proposed cotidal maps. Ocean tide information was extracted from tidal gravity profiles made with correctly intercalibrated gravimeters at 91 tidal gravity stations by the subtraction of

P. Melchior; M. Moens; B. Ducarme; M. van Ruymbeke

1981-01-01

254

A heterogeneous population model for contagious bovine pleuropneumonia transmission and control in pastoral communities of East Africa  

Microsoft Academic Search

Pastoral cattle live in highly structured communities characterized by complex contact patterns. The present paper describes a spatially heterogeneous model for the transmission of contagious bovine pleuropneumonia (CBPP) developed specifically for pastoral communities of East Africa. The model is validated against serological data on the prevalence of CBPP infection in several communities of southern Sudan and against livestock owner information

J. C. Mariner; J. McDermott; J. A. P. Heesterbeek; G. Thomson; P. L. Roeder; S. W. Martin

2006-01-01

255

Comparative SWOT analysis of strategic environmental assessment systems in the Middle East and North Africa region.  

PubMed

This paper presents a SWOT analysis of SEA systems in the Middle East North Africa region through a comparative examination of the status, application and structure of existing systems based on country-specific legal, institutional and procedural frameworks. The analysis is coupled with the multi-attribute decision making method (MADM) within an analytical framework that involves both performance analysis based on predefined evaluation criteria and countries' self-assessment of their SEA system through open-ended surveys. The results show heterogenous status with a general delayed progress characterized by varied levels of weaknesses embedded in the legal and administrative frameworks and poor integration with the decision making process. Capitalizing on available opportunities, the paper highlights measures to enhance the development and enactment of SEA in the region. PMID:23648267

Rachid, G; El Fadel, M

2013-08-15

256

Forest History in East Africa's Eastern Arc Mountains: Biological Science and the Uses of History  

NSDL National Science Digital Library

In this article, I argue that conservation science in its role of advocate for the natural world could profitably draw from site-specific histories that integrate human and natural histories. Both fields analyze the dynamic interaction of structure and process. In East Africa's Eastern Arc Mountains, where forests contain high levels of species endemism and biological diversity, the prevailing historical paradigm from conservation science represents today's forests as surviving fragments of much larger forests. This view builds upon a century-long tradition of scientific scholarship that has developed theories for the evolution of Eastern Arc forests that encompass geological time scales. However, the relatively brief, millennial-scale land-use history of the mountains, insofar as it is currently understood, suggests that human manipulation of forest biota involved periods of deforestation and regeneration, as well as the introduction of exotic plants.

Christopher Conte (Utah State University;Department of History)

2010-04-07

257

Chronology of volcanism and rift basin propagation - Rungwe volcanic province, East Africa  

NASA Technical Reports Server (NTRS)

The spatial and temporal development of along-axis segmentation in youthful continental rifts was investigated using the results of field, remote sensing, and K-Ar geochronology studies conducted in four (Rukwa, Songwe, Usangu, and Karonga) rift basins within the Rungwe volcanic province in East Africa. Results indicated that the Rukwa and Karonga border fault segments formed between 7.25 and 5 m.y. ago, the Usangu border fault segment developed between 3 and 2 m.y. ago, and subsidence along the Songwe border fault segment had occurred by 0.5 Ma. It is shown that individual basins developed diachronously, each following a similar sequence: (1) initial border fault development; (2) asymmetric basin subsidence/flank uplift and the development of monoclines opposite the border faults; and (3) continued subsidence and tilting along intrabasinal faults with flexural upwarping of the rift flanks, enhancing basinal asymmetries.

Ebinger, C. J.; Deino, A. L.; Drake, R. E.; Tesha, A. L.

1989-01-01

258

Silent Epidemic of Depression in Women in the Middle East and North Africa Region  

PubMed Central

Background: As the world is being gripped by economic depression, international psychological epidemiologists have amassed evidence to suggest that psychological depression and its variants are becoming leading contributors to the global burden of disease with the Middle East and North Africa (MENA) region being no exception. Aim: The main aim of the present discourse, based on a review of the available literature, is to discuss critically whether women in the MENA region have a higher rate of psychological depression than those in other parts of the globe. Result: From the present synthesis, it emerges that the rate of depression may not be necessarily unique to the region. Conclusion: Although no society has totally overcome the marginalisation and lack of empowerment of women, in order to come to grips to this complex issue more vigorously designed epidemiological studies, using taxonomies that are standardised for cross-cultural populations, are needed to quantify the psychological functioning of women.

Eloul, Liyam; Ambusaidi, Aamal; Al-Adawi, Samir

2009-01-01

259

Diet, Genetics, and Disease: A Focus on the Middle East and North Africa Region  

PubMed Central

The Middle East and North Africa (MENA) region suffers a drastic change from a traditional diet to an industrialized diet. This has led to an unparalleled increase in the prevalence of chronic diseases. This review discusses the role of nutritional genomics, or the dietary signature, in these dietary and disease changes in the MENA. The diet-genetics-disease relation is discussed in detail. Selected disease categories in the MENA are discussed starting with a review of their epidemiology in the different MENA countries, followed by an examination of the known genetic factors that have been reported in the disease discussed, whether inside or outside the MENA. Several diet-genetics-disease relationships in the MENA may be contributing to the increased prevalence of civilization disorders of metabolism and micronutrient deficiencies. Future research in the field of nutritional genomics in the MENA is needed to better define these relationships.

Fahed, Akl C.; El-Hage-Sleiman, Abdul-Karim M.; Farhat, Theresa I.; Nemer, Georges M.

2012-01-01

260

Holocene precipitation and thermal coherence at Lakes Albert and Victoria, East Africa  

NASA Astrophysics Data System (ADS)

New molecular proxy records of temperature and rainfall from lacustrine sedimentary archives are helping to constrain the tropical response to global climate change and elucidate possible forcing mechanisms during the latest Pleistocene and Holocene in East Africa. It is often noted that tropical ecosystems are more sensitive to perturbations in rainfall than in temperature, due to the limited thermal range of tropical climate, however coincident shifts would likely enhance climate response to regional variability. Furthermore, on shorter time scales, patterns of moisture balance and temperature are often linked in East Africa. Here we present new records of rainfall from Lakes Albert and Victoria, using compound specific ?D from terrestrial leaf waxes, and compare these trends to TEX86 paleotemperature records in order to assess the coherence between tropical precipitation and temperature. Our results indicate generally synchronous shifts at these sites, roughly in-phase with regional climate behavior during this interval. A high resolution climate history at Lake Albert highlights a significant multi-stage cool and arid excursion characteristic of the last deglaciation, beginning ~13.8 ka and ending rapidly at ~11.5 ka and marked by a ~55% D-enrichment and 3°C cooling, linking this tropical region to high latitude climate events. The molecular perspective on the climate surrounding Lake Victoria indicates a warm, humid interval peaking at 10-9 ka, and subsequent gradual cooling and drying over the remainder of the Holocene, exhibiting shifts of ~40% in ?D and ~5°C, and thus showing a strong correlation to summer insolation. Palynological and ?13C biomarker evidence from these sites indicate significant, but not coinciding, shifts in aspects of the terrestrial vegetation ecosystem that are not well understood. Both regions support a linkage between high latitude and equatorial African climate systems, with likely teleconnections to the Indian monsoon system.

Berke, M. A.; Johnson, T. C.; Werne, J. P.; Grice, K.; Schouten, S.; Sinninghe Damsté, J. S.

2011-12-01

261

Satellite climatology and the environmental risk of Schistosoma mansoni in Ethiopia and east Africa.  

PubMed

Annual and seasonal composite maps prepared from the normalized difference vegetation index (NDVI) and earth surface maximum temperature (T(max)) satellite data from the archives of the Global land 1-km program of the United States Geological Survey (USGS) were studied for. their potential value, using geographic information system (GIS) methods, as surrogates of climate data in the development of environmental risk models for schistosomiasis in Ethiopia. Annual, wet season and dry season models were developed and iteratively analyzed for relationships with Schistosoma mansoni distribution and infection prevalence rates. Model-predicted endemic area overlays that best fit the distribution of sites with over 5% prevalence corresponded to values of NDVI 125-145 and T(max) 20-33 degrees C in the annual composite map, NDVI 125-145 and T(max) 18-29 degrees C for the wet season map, and NDVI 125-140 and T(max) 22-37 degrees C for the dry season map. The model-predicted endemic area was similar to that of a prior model developed using an independent agroecologic zone data set from the United Nations Food and Agriculture Organization (FAO). Results were consistent with field and laboratory data on the preferences and limits of tolerance of the S. mansoni-Biomphalaria pfeifferi system. Results suggest that Global 1-km NDVI and T(max), when used together, can be used as surrogate climate data for development of GIS risk assessment models for schistosomiasis. The model developed for Ethiopia based on global 1-km satellite data was extrapolated to a broader area of East Africa. When used with FAO agroecologic zone climate data limits of <27 degrees C for average annual mean temperature and annual moisture deficits (annual rain-annual potential evapotranspiration) of <-1300 mm, the model accurately represented the regional distribution of the S. mansoni-B. pfeifferi system in the East Africa extrapolation area. PMID:11378142

Malone, J B; Yilma, J M; McCarroll, J C; Erko, B; Mukaratirwa, S; Zhou, X

2001-04-27

262

Accuracy of teleseismic event locations in the Middle East and North Africa  

SciTech Connect

Seismic characterization at the regional level requires accurate determination of phases and travel times for many combinations of stations and events. An important consideration in the process is the accuracy of event locations. The LLNL Comprehensive Test Ban Treaty Research Program is currently working on data from the Middle East and North Africa, where seismic station coverage is relatively sparse and ``ground truth`` seismic source information is practically nonexistent. In this report the investigator use after shock studies as a source of local ground truth. He evaluates teleseismic location accuracy by comparing hypocenters determined by local networks with those determined teleseismically [e.g. the International Seismological Center (ISC) and the National Earthquake Information Center (NEIC)]. Epicentral locations, origin times, and depth determinations of events from three aftershocks studies (Algeria, Armenia, and Iran) and one local network study (Iran) are compared with ISC and NEIC locations for the same events. The key parameter for the ISC locations is the number of observations used in the location determination. For more than 40-50 observations, the agreement rapidly diminishes and ISC locations can differ from local determinations by as much as 80 km or more. Events in Iran show a distinct bias of ISC location errors toward the northeast; events in Armenia and Algeria show no directional bias. This study shows that only events with ISC M{sub b} {gt} 4.4-4.5 or NEIS M{sub b} {gt} 4.7-4. should be used for compiling travel time information from teleseismic bulletins in the Middle East/North Africa region when locations from the NEIC and ISC bulletins are used.

Sweeney, J.J.

1996-12-04

263

MENA 1.1 - An Updated Geophysical Regionalization of the Middle East and North Africa  

SciTech Connect

This short report provides an update to the earlier LLNL paper entitled ''Preliminary Definition of Geophysical Regions for the Middle East and North Africa'' (Sweeney and Walter, 1998). This report is designed to be used in combination with that earlier paper. The reader is referred to Sweeney and Walter (1998) for all details, including definitions, references, uses, shortcomings, etc., of the regionalization process. In this report we will discuss only those regions in which we have changed the boundaries or velocity structure from that given by the original paper. The paper by Sweeney and Walter (1998) drew on a variety of sources to estimate a preliminary, first-order regionalization of the Middle East and North Africa (MENA), providing regional boundaries and velocity models within each region. The model attempts to properly account for major structural discontinuities and significant crustal thickness and velocity variations on a gross scale. The model can be used to extrapolate sparse calibration data within a distinct geophysical region. This model can also serve as a background model in the process of forming station calibration maps using intelligent interpolation techniques such as kriging, extending the calibration into aseismic areas. Such station maps can greatly improve the ability to locate and identify seismic events, which in turn improves the ability to seismically monitor for underground nuclear testing. The original model from Sweeney and Walter (1998) was digitized to a 1{sup o} resolution, for simplicity we will hereafter refer to this model as MENA 1.0. The new model described here has also been digitized to a 1{sup o} resolution and will be referred to as MENA1.1 throughout this report.

Walters, B.; Pasyanos, M.E.; Bhattacharyya, J.; O'Boyle, J.

2000-03-01

264

Indian Ocean Climate event brings floods to East Africa's lakes and the Sudd Marsh  

NASA Astrophysics Data System (ADS)

During an El Niño, the expected rainfall increase over most of the Lake Victoria catchment area is ˜15-25%. However, due to anomalous warming of the western equatorial Indian Ocean during 1997, strong convection developed over parts of the Horn and eastern Africa. This resulted in a much larger 20-160% precipitation excess during the “short rainy” season. Satellite radar altimetry data reveals that not only did Lake Victoria rise by ˜1.7 m, but that the rainfall event similarly affected lakes Tanganyika, Malawi and Turkana. In addition, the seasonal level minima of the Sudd marshes and Lakes T'ana and Nasser continue to increase. Such a rainfall event will have severe, long-term consequences for the natural surface flows and storages along the White Nile. Based on the hydrological impacts of the historic 1961 East Africa event, we can expect the current high levels of Lake Victoria to be maintained for the remainder of this decade. In addition, we anticipate a major expansion of the permanent swamp regions of the Sudd marshes over the forthcoming seasons. Blue Nile flows, further enhanced by the above-average 1998 rainfall season, can also be expected to remain high, at least until early 1999.

Birkett, Charon; Murtugudde, Ragu; Allan, Tony

265

Geology and petroleum resources of central and east-central Africa  

SciTech Connect

The petroleum provinces of central and east-central Africa include the Somali basin, the Ethiopian plateau and rift belt, and the central African rift basins. The western shelf on the Somali basin in the horn of Africa contains a sedimentary cover 1000-10,000 m (3000-3500 ft) thick of Mesozoic and Tertiary marine and continental clastic, carbonate, and evaporite deposits with good reservoir and potentially adequate source rock properties. To date, no commercial oil or gas discoveries have been made. The Ethiopian plateau and rift belt is a high-risk area with minimum potential for commercial petroleum because the Neogene rifting origin of the province has resulted in high geothermal gradients, extensive volcanism, and inadequate marine deposits and petroleum source rocks. The central Africa interior basins are continental craton-rifted depressions of Late Cretaceous and Tertiary age containing as much as 4000 m (13,000 ft) or more of fluvial and lacustrine clastic beds, which inter-tongue with nearshore marine clastic and carbonate beds in the western basins. Since the mid-1970s, approximately 13 oil discoveries have been made in the Upper Nile, Doba-Doseo, and Chad basins. These basins produce from fluvial and lacustrine sandstone reservoirs, sourced by lacustrine organic shale beds of Cretaceous age. The Benue trough is a rifted depression of middle Cretaceous age adjoined on the southwest by the prolific Niger Delta petroleum province. The trough is filled with 6000 m (20,000 ft) or more of clastic and carbonate marine and continental rocks of late Early Cretaceous and early Cenozoic age. Very few exploratory wells have been drilled, and no commercial discoveries have been made although good reservoir and source rocks are present.

Peterson, J.A.

1986-05-01

266

Solar Forcing of climate fluctuations in East Africa recorded in southeastern Mediterranean sediments  

NASA Astrophysics Data System (ADS)

The proportions of terrigenous components in Mediterranean sediments derived from the atmosphere and rivers strongly depend on climate conditions in the source areas. The rainfall regimes of the northern and central part of the African continent are controlled by an interplay between global climate patterns and the regional hydrological balance. High-resolution XRF element records of a marine sediment core of the southeastern Levantine Sea (Mediterranean Sea; GeoTü SL112, 32° 44.52 N, 34° 39.02 E, water depth: 892 m) indicate distinctive changes in the sediment supply to the southeastern Mediterranean by the Nile River as well as the influx of aeolian dust from the Saharan desert. We observe minima in the concentration of the element iron (Fe), which we interpret as minima in dust input, during the well-known solar minima Oort, Wolf, Spoerer, Maunder, and Dalton. Wavelet analyses reveals a close correspondence in the periodicity in Fe input with the typical frequencies of solar cycles of about 90 and 210 years during the last 1400 years. Furthermore, the Fe record from the Levantine Sea sediments shows a remarkable similarity with the lake level record of Lake Naivasha in the eastern branch of the East African Rift and the pre-colonial drought history of Lake Malawi in the southern part of the African Rift Valley. Enhanced Saharan dust flux as indicated by high Fe content in the Levantine Sea core coincides with well-known droughts in equatorial east Africa as indicated by Lake Naivasha lowstands.

Hamann, Y.; Dulski, P.; Hajdas, I.; Ehrmann, W. U.; Schmiedl, G. H.; Haug, G. H.

2010-12-01

267

Surgical Efficiencies and Quality in the Performance of Voluntary Medical Male Circumcision (VMMC) Procedures in Kenya, South Africa, Tanzania, and Zimbabwe  

PubMed Central

Introduction This analysis explores the association between elements of surgical efficiency in voluntary medical male circumcision (VMMC), quality of surgical technique, and the amount of time required to conduct VMMC procedures in actual field settings. Efficiency outcomes are defined in terms of the primary provider’s time with the client (PPTC) and total elapsed operating time (TEOT). Methods Two serial cross-sectional surveys of VMMC sites were conducted in Kenya, Republic of South Africa, Tanzania and Zimbabwe in 2011 and 2012. Trained clinicians observed quality of surgical technique and timed 9 steps in the VMMC procedure. Four elements of efficiency (task-shifting, task-sharing [of suturing], rotation among multiple surgical beds, and use of electrocautery) and quality of surgical technique were assessed as explanatory variables. Mann Whitney and Kruskal Wallis tests were used in the bivariate analysis and linear regression models for the multivariate analyses to test the relationship between these five explanatory variables and two outcomes: PPTC and TEOT. The VMMC procedure TEOT and PPTC averaged 23–25 minutes and 6–15 minutes, respectively, across the four countries and two years. The data showed time savings from task-sharing in suturing and use of electrocautery in South Africa and Zimbabwe (where task-shifting is not authorized). After adjusting for confounders, results demonstrated that having a secondary provider complete suturing and use of electrocautery reduced PPTC. Factors related to TEOT varied by country and year, but task-sharing of suturing and/or electrocautery were significant in two countries. Quality of surgical technique was not significantly related to PPTC or TEOT, except for South Africa in 2012 where higher quality was associated with lower TEOT. Conclusions SYMMACS data confirm the efficiency benefits of task-sharing of suturing and use of electrocautery for decreasing TEOT. Reduced TEOT and PPTC in high volume setting did not result in decreased quality of surgical care.

Rech, Dino; Bertrand, Jane T.; Thomas, Nicholas; Farrell, Margaret; Reed, Jason; Frade, Sasha; Samkange, Christopher; Obiero, Walter; Agot, Kawango; Mahler, Hally; Castor, Delivette; Njeuhmeli, Emmanuel

2014-01-01

268

Temperature and hydrologic variability of Lake Victoria, East Africa since the Late Pleistocene  

NASA Astrophysics Data System (ADS)

Recent organic geochemical advances have facilitated the comparison between continental temperature change and hydrologic variability. TEX86, a proxy based on the lipids of aquatic Crenarchaeota that show a positive correlation with growth temperature, was used to reconstruct surface water temperatures from Lake Victoria, East Africa during the latest Pleistocene-Holocene. Hydrologic conditions were interpreted using paleoecological implications of shifting pollen and diatom assemblages found in the lake (Kendall, 1969; Stager et al., 2003) and will be compared with future compound specific ?13C data from terrestrial biomarkers in order to determine the patterns of rainfall and aridity in this region. Initial comparisons of climatic changes seen in temperature and hydrologic records appear to show consistency between warm/wet intervals and cool/dry intervals that is often assumed, but more rarely shown, in tropical Africa. Lake Victoria temperatures show a steady warming beginning 16 cal ka, with a pause around the Younger Dryas, dominated by arid conditions and strong savannah grassland development during this interval. There is continued warming to a sustained thermal maximum for this portion of the record at ~10.5-8.5 ka, which generally coincides with the beginning of the Holocene Hypsithermal, an interval of elevated temperatures and precipitation throughout much of tropical Africa. This thermal maximum occurs during the most humid interval of this record (~9.5-8.3 ka), shown by an increase of humid forest pollen and high diatom abundance (due to increased water column mixing and nutrient runoff). Temperatures abruptly cool ~1.5°C in <800 years while precipitation becomes somewhat more seasonally restricted, coinciding with an abrupt drop in inferred P:E ratio and reduction in wind-driven mixing. The record then shows a general cooling, reaching a Holocene thermal minimum of ~18.4°C at ~4.5 ka, contrary to other East African continental and marine paleoclimate records that exhibit a Holocene thermal maximum ~5 ka. These coolest Holocene temperatures correspond to the driest interval in the surrounding region (~5.8-2.7 ka), with an increase in grassland abundance and decrease in humid forest pollen. Though a 5 ka thermal maximum is not seen in Lake Victoria, this portion of the record shows a temperature inflection and variable hydrologic signals, potentially marking a response to the end of the Holocene Hypsithermal, where temperatures begin to rise ~3°C over the remainder of the record.

Berke, M. A.; Johnson, T. C.; Werne, J. P.; Schouten, S.; Sinninghe Damste, J. S.

2010-12-01

269

New Proxies from Loess-Paleosols on Mount Kilimanjaro document Late Pleistocene Megadroughts in East Africa  

NASA Astrophysics Data System (ADS)

Innovative, new proxies from loess and paleosol sediments hold great potential to obtain more quantitative information about paleoclimate changes in terrestrial environments. Here we present results from lipid biomarkers (GDGTs) and hydrogen isotopic measurements on long-chain fatty acids and alkanes that we extracted from 69 paleosol samples from Mt Kilimanjaro, Tanzania (~3°S). The respective soil pit and sediment core at ~2700 m above sea level is radiocarbon-dated to 38.4 ka BP, and probably covers most of the Late Pleistocene, making it one of the longest, continuous, terrestrial archives in the East African tropics. Our compound-specific deuterium measurements show lowest ?D values from ~9 to 5 ka in the Early/Middle Holocene, consistent with regional evidence for an “African Humid Period,” followed by a shift towards more arid conditions during the Late Holocene (~5‰ shift). The Younger Dryas is characterized by a ?D enrichment (=aridity) of ~15‰ compared to the Early/Middle Holocene, almost reaching LGM values (~20‰ shift). The enrichment during the LGM is, however, significantly smaller than the 50‰ change as observed in Lake Tanganyika further southwest. At present it is not possible to determine whether these differences result from geographic variations in precipitation and humidity, or isotopic distillation processes along the vapor transport trajectories across East Africa. Much more arid conditions (~40‰ enrichment) can be inferred for the paleosols older than ~60 ka. Although further dating efforts are required to determine the exact timing, this corroborates earlier findings from African lakes that suggested ‘megadroughts’ occurred during Marine Isotope Stages 5 and 4. Acknowledging the general perception that precipitation in East Africa is strongly controlled by ITCZ positioning, we highlight the role of (strong) eccentricity in modulating the precessional forcing, which - in combination with high-latitude glacial boundary conditions - may have caused extreme amplitudes of seasonal ITCZ migration and corresponding variability of climate conditions in the tropics on orbital timescales. Counter-intuitively, our GDGT temperature reconstruction based on MBT and CBT indices shows temperatures ~5°C warmer throughout the LGM and MIS3 than during the Holocene. Although local soil temperature may be affected by vegetation and/or cloud cover, such results advice caution and highlight the necessity to further validate and develop these new biomarker proxies.

Zech, R.; Huang, Y.; Russell, J. M.; Tarozo, R.; Gao, L.; Hemp, A.; Zech, W.

2009-12-01

270

Rayleigh wave group velocity dispersion across Northern Africa, Southern Europe and the Middle East  

SciTech Connect

THis report presents preliminary results from a large scale study of surface wave group velocity dispersion throughout Northern Africa, the Mediterranean, Southern Europe and the Middle East. Our goal is to better define the 3D lithospheric shear-wave velocity structure within this region by improving the resolution of global surface wave tomographic studies. We hope to accomplish this goal by incorporating regional data at relatively short periods (less than 40 sec), into the regionalization of lateral velocity variation. Due to the sparse distributions of stations and earthquakes throughout the region (Figure 1) we have relied on data recorded at both teleseismic and regions; distances. Also, to date we have concentrated on Rayleigh wave group velocity measurements since valuable measurements can be made without knowledge of the source. In order to obtain Rayleigh wave group velocity throughout the region, vertical component teleseismic and regional seismograms were gathered from broadband, 3-component, digital MEDNET, GEOSCOPE and IRIS stations plus the portable PASSCAL deployment in Saudi Arabia. Figure 1 shows the distribution of earthquakes (black circles) and broadband digital seismic stations (white triangles) throughout southern Europe, the middle east and northern Africa used in this study. The most seismicly active regions of northern Africa are the Atlas mountains of Morocco and Algeria as well as the Red Sea region to the east. Significant seismicity also occurs in the Mediterranean, southern Europe and throughout the high mountains and plateaus of the middle-east. To date, over 1300 seismograms have been analyzed to determine the individual group velocities of 10-150 second Rayleigh waves. Travel times, for each period, are then inverted in a back projection tomographic method in order to determine the lateral group velocity variation throughout the region. These results are preliminary, however, Rayleigh wave group velocity maps for a range of periods (10-95 sec) are presented and initial interpretations are discussed. Significant lateral group velocity variation is apparent at all periods. In general, shorted periods (10-45 sec) are sensitive to crustal structure as seen by the relatively low velocities associated with large sedimentary features (eastern Arabian shield, Persian Gulf, Eastern Mediterranean, Caspian Sea). At longer periods (50-95 sec), Rayleigh waves are most sensitive to topography on the Moho and upper mantle shear-wave velocity structure. This is observed in the group velocity maps as low velocities associated with features such as the Zagros Mountains, Iranian Plateau and the Red Sea. Analysis will eventually be expanded to include Love wave group and phase velocity. Knowledge of the lateral variation of group velocity and phase velocity will allow us to invert for shear velocity at each grid point. A detailed regionalization of shear-wave velocity will potentially lower the threshold for Ms determinations and improve event location capabilities throughout the region. Better Ms estimates and locations will improve our ability to reliably monitor the Comprehensive Test Ban Treaty (CTBT).

McNamara, D.E.; Walter, W.R.

1997-07-15

271

Climate Change Impact Assessment and Adaptation Options in Vulnerable Agro-Landscapes in East-Africa  

NASA Astrophysics Data System (ADS)

Climate change poses a risk to the livelihoods of large populations in the developing world, especially in Africa. In East Africa, climate change is expected to affect the spatial distribution and quantity of precipitation. The proposed project will assess aspects of climate impacts and adaptation options in Tanzania. The project will attempt to quantify (1) projected impacts including: variability in temperature, rainfall, flooding and drought (2) the affect changes in 1. will have on specific sectors namely agriculture (food security), water resources and ecosystem services. The cumulative effects of diminished surface and ground water flow on agricultural production coupled with increasing demand for food due to increase in human pressure will also be evaluated. Expected outputs of the project include (1) downscaled climate change scenarios for different IPCC emission scenarios (2) model based estimations of climate change impacts on hydrological cycle and assessment of land use options (3) scenarios of sustainable livelihoods and resilient agro-landscapes under climate change (4) assessment of adaptive practices and criteria for best adaptation practices. The presentation will focus on novel approaches that focus on the use of agro-ecosystem models to predict local and regional impacts of climate variability on food with specific needs of the end-user factored into model set-up process. In other words, model configurations adapted to the information needs of a specific end-user or audience are evaluated. The perception of risk within different end-users (small scale farmer versus a regional or state level policy maker) are explicitly taken into consideration with the overarching aim of maximizing the impact of the results obtained from computer-based simulations.

Manful, D.; Tscherning, K.; Kersebaum, K.; Dietz, J.; Dietrich, O.; Gomani, C.; Böhm, H.; Büchner, M.; Lischeid, G.,; Ojoyi, M.,

2009-04-01

272

Monitoring the water balance of Lake Victoria, East Africa, from space  

NASA Astrophysics Data System (ADS)

SummaryUsing satellite gravimetric and altimetric data, we examine trends in water storage and lake levels of multiple lakes in the Great Rift Valley region of East Africa for the years 2003-2008. GRACE total water storage estimates reveal that water storage declined in much of East Africa, by as much as 60 {mm}/{year}, while altimetric data show that lake levels in some large lakes dropped by as much as 1-2 m. The largest declines occurred in Lake Victoria, the Earth's second largest freshwater body. Because the discharge from the outlet of Lake Victoria is used to generate hydroelectric power, the role of human management in the lake's decline has been questioned. By comparing catchment water storage trends to lake level trends, we confirm that climatic forcing explains only about 50decline. This analysis provides an independent means of assessing the relative impacts of climate and human management on the water balance of Lake Victoria that does not depend on observations of dam discharge, which may not be publically available. In the second part of the study, the individual components of the lake water balance are estimated. Satellite estimates of changes in lake level, precipitation, and evaporation are used with observed lake discharge to develop a parameterization for estimating subsurface inflows due to changes in groundwater storage estimated from satellite gravimetry. At seasonal timescales, this approach provides closure to Lake Victoria's water balance to within 17 {mm}/{month}. The third part of this study uses the water balance of a downstream water body, Lake Kyoga, to estimate the outflow from Lake Victoria remotely. Because Lake Kyoga is roughly 20 times smaller in area than Lake Victoria, its water balance is strongly influenced by inflow from Lake Victoria. Lake Kyoga has been shown to act as a linear reservoir, where its outflow is proportional to the height of the lake. This model can be used with satellite altimetric lake levels to estimate a time series of Lake Victoria discharge with an rms error of about 134 {m}/{s}.

Swenson, Sean; Wahr, John

2009-05-01

273

A seasonal agricultural drought forecast system for food-insecure regions of East Africa  

NASA Astrophysics Data System (ADS)

The increasing food and water demands of East Africa's growing population are stressing the region's inconsistent water resources and rain-fed agriculture. More accurate seasonal agricultural drought forecasts for this region can inform better water and agricultural management decisions, support optimal allocation of the region's water resources, and mitigate socio-economic losses incurred by droughts and floods. Here we describe the development and implementation of a seasonal agricultural drought forecast system for East Africa (EA) that provides decision support for the Famine Early Warning Systems Network's science team. We evaluate this forecast system for a region of equatorial EA (2° S to 8° N, and 36° to 46° E) for the March-April-May growing season. This domain encompasses one of the most food insecure, climatically variable and socio-economically vulnerable regions in EA, and potentially the world: this region has experienced famine as recently as 2011. To assess the agricultural outlook for the upcoming season our forecast system simulates soil moisture (SM) scenarios using the Variable Infiltration Capacity (VIC) hydrologic model forced with climate scenarios for the upcoming season. First, to show that the VIC model is appropriate for this application we forced the model with high quality atmospheric observations and found that the resulting SM values were consistent with the Food and Agriculture Organization's (FAO's) Water Requirement Satisfaction Index (WRSI), an index used by FEWS NET to estimate crop yields. Next we tested our forecasting system with hindcast runs (1993-2012). We found that initializing SM forecasts with start-of-season (5 March) SM conditions resulted in useful SM forecast skill (> 0.5 correlation) at 1-month, and in some cases at 3 month lead times. Similarly, when the forecast was initialized with mid-season (i.e. 5 April) SM conditions the skill until the end-of-season improved. This shows that early-season rainfall is critical for end-of-season outcomes. Finally we show that, in terms of forecasting spatial patterns of SM anomalies, the skill of this agricultural drought forecast system is generally greater (> 0.8 correlation) during drought years. This means that this system might be particularity useful for identifying the events that present the greatest risk to the region.

Shukla, S.; McNally, A.; Husak, G.; Funk, C.

2014-03-01

274

Focal mechanisms from regional earthquakes in East Africa and refinements in stress patterns  

NASA Astrophysics Data System (ADS)

Accurate event locations for eleven events with magnitude greater than 3.5 in Tanzania, East Africa have been obtained using data from the Tanzania Broadband Seismic Experiment. Focal mechanisms for most of these events have been determined by modeling P and SH polarities and amplitude ratios in a grid search method. Epicenters have been constrained by using P and S arrival times. Focal depths have been constrained by waveform modeling of regional and local depth phases. Most of the earthquakes occur in two areas along the western or eastern branch of the East African Rift. The first area is located between southern Lake Tanganyika and Lake Rukwa in the western branch, and the mechanisms in this region are characterized by strike-slip or oblique extension with nodal planes striking E-W to NW-SE. These events confirm that this part of the western rift is under transtension, as compared to the Lake Tanganyika and Rukwa rifts, where the stress field appears to be almost purely extensional. The second area for which we have obtained several new focal mechanisms is near the southern end of the eastern branch where the rift impinges on the eastern margin of the Tanzania craton. The focal mechanisms from this part of the rift have strike slip or normal motions but the orientations of the nodal planes are complex, consistent with the complicated orientation of the block faults. The focal depths for the events in the first area vary from 7 to 36 km, and in the second area, they vary from 11 to 34 km.

Brazier, R. A.; Nyblade, A.

2004-12-01

275

Urban Leptospirosis in Africa: A Cross-Sectional Survey of Leptospira Infection in Rodents in the Kibera Urban Settlement, Nairobi, Kenya  

PubMed Central

Leptospirosis is a widespread but under-reported cause of morbidity and mortality. Global re-emergence of leptospirosis has been associated with the growth of informal urban settlements in which rodents are thought to be important reservoir hosts. Understanding the multi-host epidemiology of leptospirosis is essential to control and prevent disease. A cross-sectional survey of rodents in the Kibera settlement in Nairobi, Kenya was conducted in September–October 2008 to demonstrate the presence of pathogenic leptospires. A real-time quantitative polymerase chain reaction showed that 41 (18.3%) of 224 rodents carried pathogenic leptospires in their kidneys, and sequence data identified Leptospira interrogans and L. kirschneri in this population. Rodents of the genus Mus (37 of 185) were significantly more likely to be positive than those of the genus Rattus (4 of 39; odds ratio = 15.03). Questionnaire data showed frequent contact between humans and rodents in Kibera. This study emphasizes the need to quantify the public health impacts of this neglected disease at this and other urban sites in Africa.

Halliday, Jo E. B.; Knobel, Darryn L.; Allan, Kathryn J.; de C. Bronsvoort, B. Mark; Handel, Ian; Agwanda, Bernard; Cutler, Sally J.; Olack, Beatrice; Ahmed, Ahmed; Hartskeerl, Rudy A.; Njenga, M. Kariuki; Cleaveland, Sarah; Breiman, Robert F.

2013-01-01

276

What Should the Ideal HIV Self-Test Look Like? A Usability Study of Test Prototypes in Unsupervised HIV Self-Testing in Kenya, Malawi, and South Africa.  

PubMed

HIV self-testing (HIVST) is increasingly being sought and offered globally, yet there is limited information about the test features that will be required for an HIV self-test to be easy to use, acceptable to users, and feasible for manufacturers to produce. We conducted formative usability research with participants who were naïve to HIVST using five prototypes in Kenya, Malawi, and South Africa. The tests selected ranged from early-stage prototypes to commercially ready products and had a diverse set of features. A total of 150 lay users were video-recorded conducting unsupervised self-testing and interviewed to understand their opinions of the test. Participants did not receive a test result, but interpreted standardized result panels. This study demonstrated that users will refer to the instructions included with the test, but these can be confusing or difficult to follow. Errors were common, with less than 25 % of participants conducting all steps correctly and 47.3 % of participants performing multiple errors, particularly in sample collection and transfer. Participants also had difficulty interpreting results. To overcome these issues, the ideal HIV self-test requires pictorial instructions that are easy to understand, simple sample collection with integrated test components, fewer steps, and results that are easy to interpret. PMID:24947852

Peck, Roger B; Lim, Jeanette M; van Rooyen, Heidi; Mukoma, Wanjiru; Chepuka, Lignet; Bansil, Pooja; Knight, Lucia C; Muturi, Nelly; Chirwa, Ellen; Lee, Arthur M; Wellhausen, Jeff D; Tulloch, Olivia; Taegtmeyer, Miriam

2014-07-01

277

Drivers of actual evapotranspiration and runoff in East Africa during the mid-Holocene: assessments from an ecosystem model  

NASA Astrophysics Data System (ADS)

Understanding the evolution and response of the hydrological cycle under changing climate is of vital importance for human populations all around the world. Especially so in regions like East Africa, where society largely depends on the availability of water and the hydrologic conditions are highly sensitive to changes in the distribution and amount of precipitation. In this endeavor, studying past hydrological changes provides us realistic scenarios and data to better understand and predict the extent of the future hydrological changes. However while studying the past, paleovegetation, which plays a pivotal role in the paleo-hydrological cycle, is difficult to determine from fossil pollen records as pollen data can provide very limited information on spatial distribution and composition of the vegetation cover. Here ecosystem models driven by paleo-climate conditions can provide spatially-extensive information on the coupled dynamics of past vegetation and hydrological measures such as actual evapotranspiration (AET), potential evapotranspiration (PET) and runoff. In this study, we looked at AET and runoff estimates of an ecosystem model as these are important elements of water transfer in the hydrological cycle and critical for water balance calculations. We applied the ecosystem model, LPJ-GUESS, for present-day with data from Climatic Research Unit CRU TS3.20 climate dataset, and for mid-Holocene (6 kyrs BP) with data from an atmosphere-ocean coupled global climate model EC-Earth. Climate data for both periods were downscaled to a 10 arc min resolution in order to better resolve the impacts of the complex topography on vegetation distribution, AET and runoff. Comparison of the simulated AET and runoff values for East Africa, show similar patterns as annual AET estimates for the period 1961-1990 by Food and Agriculture Organization of the United Nations (FAO), and with the observed runoff data from Cogley (1998), respectively. Comparison of simulated present-day and mid-Holocene AET values suggests an increase in AET over north-eastern parts of East Africa, especially over Sudan region and Kenyan Rift during the mid-Holocene whereas a decrease in AET during the mid-Holocene over south-southeastern parts of East Africa. On the other hand, comparison of simulated present-day and mid-Holocene runoff values suggests an increase of runoff in north-eastern parts, especially along the East African Rift and decreased runoff in the southern parts of East Africa during the mid-Holocene.

Fer, Istem; Jeltsch, Florian; Tietjen, Britta; Trauth, Martin

2014-05-01

278

The Late Pleistocene - Holocene palaeolimnology of Lake Victoria, East Africa, based upon elemental and isotopic analyses of sedimentary organic matter  

Microsoft Academic Search

Three piston cores from Lake Victoria (East Africa) have been analysed for organic carbon (TOC) and nitrogen (TN) content, stable isotopes (d13C and d15N), and Hydrogen Index (HI). These data are combined with published biogenic silica and water content analyses to produce a detailed palaeolimnological history of the lake over the past ca. 17.5 ka. Late Pleistocene desiccation produced a

Michael R. Talbot; Tine Lærdal

2000-01-01

279

A palaeoecological investigation into the role of fire and human activity in the development of montane grasslands in East Africa  

Microsoft Academic Search

Human activity has been widely implicated in the origin and expansion of montane grasslands in East Africa, yet little palaeoecological\\u000a evidence exists to test whether these grasslands are natural or secondary. Pollen and charcoal data derived from two Holocene\\u000a records in the Eastern Arc mountains of Tanzania are used as a case study to investigate the supposed secondary nature of

Jemma Finch; Rob Marchant

2011-01-01

280

Sexual and bodily rights as human rights in the Middle East and North Africa.  

PubMed

A regional workshop on sexual and bodily rights as human rights in the Middle East and North Africa was held in Malta in 2003, attended by 22 NGO representatives from Jordan, Egypt, Lebanon, Palestine, Tunisia, Morocco, Algeria, Turkey, Pakistan and USA. The meeting aimed to develop strategies for overcoming human rights violations in the region with reference to law and social and political practices. Session topics included sexuality and gender identity; sexuality and sexual health; sexuality and comparative penal law; sexual rights in international documents; advocacy and lobbying. Sexual rights, sexual health and education, sexual violence and adolescent sexuality were explored in depth, including taboos and emerging trends. Specific areas of concern included marital rape, early marriages, temporary marriages, sexual orientation, premarital and extramarital sexuality, honour crimes, female genital mutilation, unmarried mothers, adolescent sexuality, unwanted pregnancies and safe abortion, sexuality in education and health services. An analysis of civil codes, penal codes and personal status codes indicated a clear imperative for legal reform. Participants heard about efforts to promote the right to sexual orientation which have already been initiated in Lebanon, Turkey and Tunisia. Networking within the region and with counterparts in other regions in comparable situations and conditions was deemed essential. PMID:15242219

Ercevik Amado, Liz

2004-05-01

281

Preliminary maps of crustal thickness and regional seismic phases for the Middle East and North Africa  

SciTech Connect

As part of the development of regional seismic discrimination methods for the Middle East and North Africa (MENA) the author is building a database of information related to seismic propagation and crustal structure as well as associated geologic-tectonic and geophysical data. He hopes to use these data to construct and test models of regional seismic propagation and evaluate various detection/discrimination scenarios. To date, the database has been developed by building on a list of references for MENA provided by the Institute for the Study of the Continents (INSTOC) at Cornell University. To this list the author has added an equal number of references resulting from his own literature search which has emphasized papers dealing with seismicity and regional and teleseismic phase data. This paper represents an initial attempt to consolidate some of the information from the database into a form useful to researchers modeling regional seismic waveforms. The information compiled in this report is supplemental to the INSTOC database and has not been compiled anywhere else. What follows is a series of maps which illustrate the spatial variation of seismic phase velocities and crustal thickness. The text identifies the sources of information used in the map preparation. Data for the compilation of these maps has come from an initial search of the database as it presently exists and is not intended to be exhaustive. The author hopes that this initial exercise will help to identify areas and types of data that are deficient and help to focus future data gathering activities.

Sweeney, J.J.

1995-09-06

282

Polyphase Neoproterozoic orogenesis within the east Africa- Antarctica orogenic belt in central and northern Madagascar  

USGS Publications Warehouse

Our recent geological survey of the basement of central and northern Madagascar allowed us to re-evaluate the evolution of this part of the East Africa-Antarctica Orogen (EAAO). Five crustal domains are recognized, characterized by distinctive lithologies and histories of sedimentation, magmatism, deformation and metamorphism, and separated by tectonic and/or unconformable contacts. Four consist largely of Archaean metamorphic rocks (Antongil, Masora and Antananarivo Cratons, Tsaratanana Complex). The fifth (Bemarivo Belt) comprises Proterozoic meta-igneous rocks. The older rocks were intruded by plutonic suites at c. 1000 Ma, 820-760 Ma, 630-595 Ma and 560-520 Ma. The evolution of the four Archaean domains and their boundaries remains contentious, with two end-member interpretations evaluated: (1) all five crustal domains are separate tectonic elements, juxtaposed along Neoproterozoic sutures and (2) the four Archaean domains are segments of an older Archaean craton, which was sutured against the Bemarivo Belt in the Neoproterozoic. Rodinia fragmented during the early Neoproterozoic with intracratonic rifts that sometimes developed into oceanic basins. Subsequent Mid- Neoproterozoic collision of smaller cratonic blocks was followed by renewed extension and magmatism. The global 'Terminal Pan-African' event (560-490 Ma) finally stitched together the Mid-Neoproterozoic cratons to form Gondwana. ?? The Geological Society of London 2011.

Key, R. M.; Pitfield, P. E. J.; Thomas, R. J.; Goodenough, K. M.; Waele, D.; Schofield, D. I.; Bauer, W.; Horstwood, M. S. A.; Styles, M. T.; Conrad, J.; Encarnacion, J.; Lidke, D. J.; O'connor, E. A.; Potter, C.; Smith, R. A.; Walsh, G. J.; Ralison, A. V.; Randriamananjara, T.; Rafahatelo, J. -M.; Rabarimanana, M.

2011-01-01

283

Geology and Nonfuel Mineral Deposits of Africa and the Middle East  

USGS Publications Warehouse

A nation's endowment of nonfuel mineral resources, relative to the world's endowment, is a fundamental consideration in decisions related to a nation's economic and environmental well being and security. Knowledge of the worldwide abundance, distribution, and general geologic setting of mineral commodities provides a framework within which a nation can make decisions about economic development of its own resources, and the economic and environmental consequences of those decisions, in a global perspective. The information in this report is part of a U.S. Geological Survey (USGS) endeavor to evaluate the global endowment of both identified and undiscovered nonfuel mineral resources. The results will delineate areas of the world that are geologically permissive for the occurrence of undiscovered selected nonfuel mineral resources together with estimates of the quantity and quality of the resources. The results will be published as a series of regional reports; this one provides basic data on the identified resources and geologic setting, together with a brief appraisal of the potential for undiscovered mineral resources in Africa and the Middle East. Additional information, such as production statistics, economic factors that affect the mineral industries of the region, and historical information, is available in U.S. Geological Survey publications such as the Minerals Yearbook and the annual Mineral Commodity Summaries (available at http://minerals.usgs.gov/minerals).

Taylor, Cliff D.; Schulz, Klaus J.; Doebrich, Jeff L.; Orris, Greta; Denning, Paul D.; Kirschbaum, Michael J.

2009-01-01

284

Diabetes in the Middle-East and North Africa: an update.  

PubMed

In recent decades, the prevalence of diabetes has risen dramatically in many countries of the International Diabetes Federation's (IDF) Middle-East and North Africa (MENA) Region. This increase has been driven by a range of factors that include rapid economic development and urbanisation; changes in lifestyle that have led to reduced levels of physical activity, increased intake of refined carbohydrates, and a rise in obesity. These changes have resulted in the countries of MENA Region now having among the highest rates of diabetes prevalence in the world. The current prevalence of diabetes in adults in the Region is estimated to be around 9.2%. Of the 34 million people affected by diabetes, nearly 17 million were undiagnosed and therefore at considerable risk of diabetes complications and poor health outcomes. Enhanced research on the epidemiology of diabetes in the MENA Region needs to be combined with more effective primary prevention of diabetes; and early detection and improved management of patients with established diabetes, including an increased focus on self-management and management in primary care and community settings. PMID:24300017

Majeed, Azeem; El-Sayed, Adel A; Khoja, Tawfik; Alshamsan, Riyadh; Millett, Christopher; Rawaf, Salman

2014-02-01

285

Evaluation of MODIS surrogates for meteorological humidity data in east Africa  

PubMed Central

Satellite remote sensing technology has shown promising results in characterizing the environment in which plants and animals thrive. Remote sensing scientists, biologists, and epidemiologists are adopting remotely sensed imagery to compensate for the paucity of weather information measured by weather stations. With measured humidity from three stations as baselines, our study reveals that Normalised Difference Vegetation Index (NDVI) and atmosphere saturation deficits at the 780 hPa pressure level (DMODIS), both of which were derived from the MODerate-resolution Imaging Spectroradiometer (MODIS) sensor, were significantly correlated with station saturation deficits (Dstn)(?r? = 0.42–0.63, p < 0.001). These metrics have the potential to estimate saturation deficits over east Africa. Four to nine days of lags were found in the NDVI responding to Dstn. For the daily estimations of Dstn, DMODIS had a better performance than the NDVI. However, both of them poorly explained the variances in daily Dstn using simple regression models (adj. R2 = 0.17–0.39). When the estimation temporal scale was changed to 16-day, their performances were similar, and both were better than daily estimations. For Dstn estimations at coarser geographic scales, given that many factors such as soil, vegetation, slope, aspect, and wind speed might complicate the NDVI response lags and model construction, DMODIS is more favourable as a proxy of the saturation deficit over ground due to its simple relationship with Dstn.

LIN, SHENGPAN; MOORE, NATHAN J.; MESSINA, JOSEPH P.; WU, JIAPING

2013-01-01

286

Mitochondrial haplotype diversity in the tortoise species Testudo graeca from North Africa and the Middle East  

PubMed Central

Background To help conservation programs of the endangered spur-thighed tortoise and to gain better insight into its systematics, genetic variation and evolution in the tortoise species Testudo graeca (Testudines: Testudinidae) was investigated by sequence analysis of a 394-nucleotide fragment of the mitochondrial 12S rRNA gene for 158 tortoise specimens belonging to the subspecies Testudo graeca graeca, Testudo graeca ibera, Testudo graeca terrestris, and a newly recognized subspecies Testudo graeca whitei. A 411-nucleotide fragment of the mitochondrial D-loop was additionally sequenced for a subset of 22 T. graeca, chosen because of their 12S gene haplotype and/or geographical origin. Results Haplotype networks generated by maximum-likelihood and neighbor-joining analyses of both the separate and the combined sequence data sets suggested the existence of two main clades of Testudo graeca, comprising Testudo graeca from northern Africa and Testudo graeca from the Turkey and the Middle East, respectively. Conclusion Mitochondrial DNA haplotyping suggests that the tortoise subspecies of T. g. graeca and T. g. ibera are genetically distinct, with a calculated divergence time in the early or middle Pleistocene. Other proposed subspecies could not clearly be recognized based upon their mt haplotypes and phylogenetic position, and were either part of the T. g. graeca or of the T. g. ibera clade, suggesting that genetic evidence for the existence of most of the 15 proposed subspecies of T. graeca is weak.

van der Kuyl, Antoinette C; Ballasina, Donato LP; Zorgdrager, Fokla

2005-01-01

287

Hepatitis A virus in the Middle East and North Africa region: a new challenge.  

PubMed

During the past three decades, a gradual shift in the age of infection with hepatitis A virus (HAV) from early childhood to adulthood has been observed. There is a general lack of updated data on HAV burden of disease, incidence and age-specific seroprevalence in countries of the Middle East and North Africa (MENA) region. The aim of this article is to review the published data on anti-HAV seroprevalence, an important tool to monitor infections rates, in countries of the MENA region and associated risk factors including water and socioeconomic data when available. Data on anti-HAV seroprevalence were found for 12 of 25 MENA countries. We show that MENA countries, similar to other areas in the world, have a clear shift in HAV incidence with a decline among young age groups and an increase among adults and older individuals. This would likely be associated with increased morbidity and increased risks of outbreaks among younger age groups. Consequently, the continuous surveillance of hepatitis A cases and the inclusion of hepatitis A vaccine in the expanded immunization programmes are needed in countries of the MENA. PMID:25040644

Melhem, N M; Talhouk, R; Rachidi, H; Ramia, S

2014-09-01

288

The Middle East and North Africa Land Data Assimilation System: First Results (Invited)  

NASA Astrophysics Data System (ADS)

The Arab region of the Middle East and North Africa (MENA) is dominated by dry, warm deserts, areas of dense population, and inefficient use of fresh water resources. Due to the scarcity, high intensity, and short duration of rainfall in the MENA, the region is prone to hydroclimatic extremes that are realized by devastating floods and times of drought. However, given its widespread water stress and the considerable demand for water, the MENA remains relatively poorly monitored. This is due in part to the shortage of MENA meteorological observations and the lack of data sharing between nations. As a result, the accurate monitoring of the dynamics of the water cycle in the MENA is difficult. This presentation will cover early results from the Land Data Assimilation System for the MENA region (MENA LDAS) designed to provide regional, gridded fields of hydrological states and fluxes relevant for water resources assessments. The MENA LDAS is envisaged to aid in the identification and evaluation of regional hydrological anomalies by synergistically combining the physically-based Catchment Land Surface Model (CLSM) with observations from several independent data products including soil-water storage variations from the Gravity Recovery and Climate Experiment (GRACE) and irrigation intensity derived from the Moderate Resolution Imaging Spectroradiometer (MODIS). In this fashion, we estimate the mean and seasonal cycle of the water budget components across the MENA to be used for flood and drought assessment.

Bolten, J. D.; Rodell, M.; Zaitchik, B. F.; Ozdogan, M.; Toll, D. L.; Engman, E. T.; Habib, S.

2010-12-01

289

Modeling water resources trends in Middle East and North Africa towards 2050  

NASA Astrophysics Data System (ADS)

Changes in water resources availability can be expected as consequences of climate change, population growth, economic development and environmental considerations. A two-stage modeling approach is used to explore the impact of these changes in the Middle East and North Africa (MENA) region. An advanced physical based distributed hydrological model is applied to determine the internal and external renewable water resources for the current situation and under future changes. Subsequently, a water allocation model is used to combine the renewable water resources with sectorial water demands. Results show that total demand in the region will increase to 132 km3 yr-1 in 2050, while total water shortage will grow to 199 km3 yr-1 in 2050 for the average climate change projection; an increase of 157 km3. This increase in shortage is the combined impact of an increase in water demand by 50% with a decrease in water supply by 12%. Uncertainty based on the output of the nine GCMs applied, reveals that expected water shortage ranges from 85 km3 to 283 km3 in 2050. The analysis shows that 22% of the water shortage can be attributed to climate change and 78% to changes in socio-economic factors.

Droogers, P.; Immerzeel, W. W.; Terink, W.; Hoogeveen, J.; Bierkens, M. F. P.; van Beek, L. P. H.; Negewo, B. D.

2012-04-01

290

Water resources trends in Middle East and North Africa towards 2050  

NASA Astrophysics Data System (ADS)

Changes in water resources availability can be expected as consequences of climate change, population growth, economic development and environmental considerations. A two-stage modeling approach is used to explore the impact of these changes in the Middle East and North Africa (MENA) region. An advanced, physically based, distributed, hydrological model is applied to determine the internal and external renewable water resources for the current situation and under future changes. Subsequently, a water allocation model is used to combine the renewable water resources with sectoral water demands. Results show that total demand in the region will increase to 393 km3 yr-1 in 2050, while total water shortage will grow to 199 km3 yr-1 in 2050 for the average climate change projection, an increase of 157 km3 yr-1. This increase in shortage is the combined impact of an increase in water demand by 50% with a decrease in water supply by 12%. Uncertainty, based on the output of the nine GCMs applied, reveals that expected water shortage ranges from 85 km3 yr-1 to 283 km3 yr-1~in 2050. The analysis shows that 22% of the water shortage can be attributed to climate change and 78% to changes in socio-economic factors.

Droogers, P.; Immerzeel, W. W.; Terink, W.; Hoogeveen, J.; Bierkens, M. F. P.; van Beek, L. P. H.; Debele, B.

2012-09-01

291

Aerosol Radiative Forcing and Regional Climate Impact over Middle East and North Africa  

NASA Astrophysics Data System (ADS)

Middle East and North Africa (MENA) is a unique region due in part to the abundance of atmospheric aerosols and their significant contribution to the energy balance of the region. Mineral dust plays a leading role in this process. In this study we evaluate the radiative forcing of dust aerosols in the MENA region and their impact on the regional circulation and temperature distribution using a global high-resolution atmospheric model HIRAM developed at the NOAA Geophysical Fluid Dynamics Laboratory. We found that dust aerosols reduce downward radiative fluxes at surface up to 30 W/m2 and warm by about this amount the lower five-km-deep atmospheric layer. To better quantify radiative impact of aerosols we have employed the available aerosol satellite observations that primarily provide column integral aerosol optical depth (AOD), as a measure of aerosol burden. Climatology of AOD from different satellites (MODIS, MISR, SEVIRI and CALIPSO) over MENA and their inter comparison is made to have a comprehension of the discrepancies and agreement between them. Though the observed AODs vary among the different instruments spatially and temporally, the difference falls within a factor of less than two. We implement these observed aerosols in HIRAM. The radiative forcing corresponding to the satellite aerosol observation and the sensitivity of regional climate to this forcing are analyzed. The analysis shows that the differential heating in the vertical and the corresponding response of the vertical temperature profile have a profound impact on the tropospheric dynamics and the structure of the boundary layer.

Bangalth, H. K.; Stenchikov, G.; Zampieri, M.; Bantges, R.; Brindley, H.

2012-04-01

292

Climate variability and conflict risk in East Africa, 1990-2009  

PubMed Central

Recent studies concerning the possible relationship between climate trends and the risks of violent conflict have yielded contradictory results, partly because of choices of conflict measures and modeling design. In this study, we examine climate–conflict relationships using a geographically disaggregated approach. We consider the effects of climate change to be both local and national in character, and we use a conflict database that contains 16,359 individual geolocated violent events for East Africa from 1990 to 2009. Unlike previous studies that relied exclusively on political and economic controls, we analyze the many geographical factors that have been shown to be important in understanding the distribution and causes of violence while also considering yearly and country fixed effects. For our main climate indicators at gridded 1° resolution (?100 km), wetter deviations from the precipitation norms decrease the risk of violence, whereas drier and normal periods show no effects. The relationship between temperature and conflict shows that much warmer than normal temperatures raise the risk of violence, whereas average and cooler temperatures have no effect. These precipitation and temperature effects are statistically significant but have modest influence in terms of predictive power in a model with political, economic, and physical geographic predictors. Large variations in the climate–conflict relationships are evident between the nine countries of the study region and across time periods.

O'Loughlin, John; Witmer, Frank D. W.; Linke, Andrew M.; Laing, Arlene; Gettelman, Andrew; Dudhia, Jimy

2012-01-01

293

The emerging face of the HIV epidemic in the Middle East and North Africa  

PubMed Central

Purpose of review A volume of quality HIV data has materialized recently in the Middle East and North Africa (MENA). This review provides a thematic narrative of the patterns of HIV infection transmission in this region in light of these data. Recent findings Tens of integrated bio-behavioral surveillance surveys among hard-to-reach key populations at higher risk have been conducted in MENA in the recent years. Many of the studies reported appreciable and growing HIV prevalence. A few studies found alarming prevalence of as much as 87.2% HIV prevalence among people who inject drugs in Tripoli, Libya. The discovery of these hitherto hidden epidemics was unsettling to some authorities after years in which the importance of a focus on HIV prevention among key populations was not recognized. Summary The new data from MENA indicate growing HIV epidemics among key populations across the region. There is heterogeneity, however, as to which key populations are affected and in what proportions in different countries. In a few countries, HIV appears to affect only one key population and often there is substantial geographical heterogeneity in HIV transmission. Data are indicative of a growing HIV disease burden in this part of the globe, in contrast with the declining epidemics in most other regions.

Mumtaz, Ghina R.; Riedner, Gabriele; Abu-Raddad, Laith J.

2014-01-01

294

Bilharziasis control in relation to water resources development in Africa and the Middle East  

PubMed Central

As part of its world-wide programme for the control of bilharziasis, the World Health Organization has set up a Bilharziasis Advisory Team, composed of an epidemiologist and an engineer, to investigate in different countries the prevalence of the disease and its relationship to irrigation, agriculture and a variety of factors associated with the development of water resources. This paper is an appraisal of the situation in 15 countries in Africa and the Middle East, based largely on surveys conducted by the Bilharziasis Advisory Team in the period 1958-60. Analyses of data from these 15 countries indicate that about 26 million people, out of a total population of 107 million, have bilharziasis. In spite of considerable expenditure on control measures, the prevalence of the disease is increasing. This trend is closely related to water resources development. On the basis of observations in the field, it is believed that improved water management and agricultural methods, stream and water impoundment control, the proper use of molluscicides and mechanical barriers, and certain aspects of environmental sanitation offer practical solutions to this problem. The complexity of these measures requires the closest co-operation between the various agencies, national and international, concerned with agriculture, water resources and public health.

McMullen, Donald B.; Buzo, Z. J.; Rainey, Marshall B.; Francotte, Jean

1962-01-01

295

The dominant Anopheles vectors of human malaria in Africa, Europe and the Middle East: occurrence data, distribution maps and bionomic précis  

Microsoft Academic Search

BACKGROUND: This is the second in a series of three articles documenting the geographical distribution of 41 dominant vector species (DVS) of human malaria. The first paper addressed the DVS of the Americas and the third will consider those of the Asian Pacific Region. Here, the DVS of Africa, Europe and the Middle East are discussed. The continent of Africa

Marianne E Sinka; Michael J Bangs; Sylvie Manguin; Maureen Coetzee; Charles M Mbogo; Janet Hemingway; Anand P Patil; Will H Temperley; Peter W Gething; Caroline W Kabaria; Robi M Okara; Thomas Van Boeckel; H Charles J Godfray; Ralph E Harbach; Simon I Hay

2010-01-01

296

Getting Books to School Pupils in Africa: Case Studies from Ghana and Tanzania, Mali, South Africa, Mozambique, and Kenya. Education Research Paper.  

ERIC Educational Resources Information Center

One of the fundamental requirements of all educational systems is the adequate provision of relevant and appropriate reading and other instructional and learning materials for use by teachers and their pupils. A study examined some of the modalities through which the school population in Africa gains access to supplementary reading materials and…

Rosenberg, Diana, Ed.

297

Early hominin diet included diverse terrestrial and aquatic animals 1.95 Ma in East Turkana, Kenya  

PubMed Central

The manufacture of stone tools and their use to access animal tissues by Pliocene hominins marks the origin of a key adaptation in human evolutionary history. Here we report an in situ archaeological assemblage from the Koobi Fora Formation in northern Kenya that provides a unique combination of faunal remains, some with direct evidence of butchery, and Oldowan artifacts, which are well dated to 1.95 Ma. This site provides the oldest in situ evidence that hominins, predating Homo erectus, enjoyed access to carcasses of terrestrial and aquatic animals that they butchered in a well-watered habitat. It also provides the earliest definitive evidence of the incorporation into the hominin diet of various aquatic animals including turtles, crocodiles, and fish, which are rich sources of specific nutrients needed in human brain growth. The evidence here shows that these critical brain-growth compounds were part of the diets of hominins before the appearance of Homo ergaster/erectus and could have played an important role in the evolution of larger brains in the early history of our lineage.

Braun, David R.; Harris, John W. K.; Levin, Naomi E.; McCoy, Jack T.; Herries, Andy I. R.; Bamford, Marion K.; Bishop, Laura C.; Richmond, Brian G.; Kibunjia, Mzalendo

2010-01-01

298

The 2005 KwaZulu-Natal sardine run survey sheds new light on the ecology of small pelagic fish off the east coast of South Africa  

Microsoft Academic Search

Despite much public awareness surrounding the annual migration of sardine Sardinops sagax northward along the east coast of South Africa in winter each year, relatively little research effort has been expended to improve understanding of the ‘sardine run’. For this reason, a dedicated multidisciplinary survey, timed to coincide with the annual sardine run, was conducted off the East Coast in

J C Coetzee; D Merkle; L Hutchings; C D van der Lingen; M van den Berg; M D Durholtz

2010-01-01

299

Agricultural Early Warning Informing Humanitarian Response in East Africa for 2012  

NASA Astrophysics Data System (ADS)

Long rains during the March-April-May (MAM) 2011 growing season were a failure for much of the Greater Horn of Africa. These conditions resulted in severe food shortages, with the Famine Early Warning Systems Network (FEWS NET) estimating that 12.4 million people were in need of food assistance in Kenya, Somalia, Ethiopia and Djibouti. Heading into the 2012 season, La Niña conditions, an exceptionally strong western-to-central Pacific sea surface temperature (SST) gradient, and warm SSTs in the eastern Indian Ocean foretold further dryness, compounding the difficulties faced by the already vulnerable populations of this region. In an effort to assess the potential for greater food insecurity in the region, FEWS NET scientists attempted to quantify the likelihood of a dry event. This work used satellite rainfall estimates with a 13-year rainfall history. Weights were assigned to previous years based on the similarity of existing SST conditions to those of previous years in the rainfall record. Scenarios were created by randomly combining dekadal rainfall from the historical record, in accordance with the weights. This bootstrapping resulted in a suite of simulations which could be used to identify the likelihood of specific rainfall outcomes. Areal averages of each simulation were used in the analysis. Analysis of the Global Precipitation Climatology Centre (GPCC) rainfall record, a gridded rainfall product based on available station data, showed that the mean rainfall value for the time period of the satellite data for this region was only about 80% of the 30-year mean. The bootstrapped scenarios were corrected for this bias during the period of the satellite record. Results were expressed as percent of average rather than in absolute rainfall amounts, to account for biases in the satellite products as well as variability in spatial amounts. The results showed that during a normal year the interquartile range is typically 80-120% of normal. However, using the weighted scenarios based on February SSTs, the interquartile range shifted to 75-105% of normal. As the season progressed, March turned out to be exceptionally dry, with a lack of onset of rains for much of the region. This delayed start to the season allowed for the combination of satellite estimates for the start of March to be combined with scenarios to look ahead to end-of-season values. By the end of March, combining estimated 2012 rains with the scenarios built before the season resulted in the interquartile range for expected outcomes dropping to 60-85% of normal. This information was relayed to FEWS NET food security analysts and used in a special report, highlighting the potential for crisis in the region. In April, this forecasting effort, combined with FEWS NET's extensive monitoring activities, helped motivate allocation of an additional $50M in food aid from the U.S. government. This presentation examines the climate conditions associated with MAM drought in the eastern sector of the Greater Horn, reviews the techniques behind the 2012 forecasts, and analyzes the actual outcome for the region. Methods for improving the work to more accurately reflect the variability and future directions and applications will be discussed.

Husak, G. J.; Funk, C. C.

2012-12-01

300

Nursing and midwifery regulatory reform in east, central, and southern Africa: a survey of key stakeholders  

PubMed Central

Background In sub-Saharan Africa, nurses and midwives provide expanded HIV services previously seen as the sole purview of physicians. Delegation of these functions often occurs informally by shifting or sharing of tasks and responsibilities. Normalizing these arrangements through regulatory and educational reform is crucial for the attainment of global health goals and the protection of practitioners and those whom they serve. Enacting appropriate changes in both regulation and education requires engagement of national regulatory bodies, but also key stakeholders such as government chief nursing officers (CNO), professional associations, and educators. The purpose of this research is to describe the perspectives and engagement of these stakeholders in advancing critical regulatory and educational reform in east, central, and southern Africa (ECSA). Methods We surveyed individuals from these three stakeholder groups with regard to task shifting and the challenges related to practice and education regulation reform. The survey used a convenience sample of nursing and midwifery leaders from countries in ECSA who convened on 28 February 2011, for a meeting of the African Health Profession Regulatory Collaborative. Results A total of 32 stakeholders from 13 ECSA countries participated in the survey. The majority (72%) reported task shifting is practiced in their countries; however only 57% reported their national regulations had been revised to incorporate additional professional roles and responsibilities. Stakeholders also reported different roles and levels of involvement with regard to nursing and midwifery regulation. The most frequently cited challenge impacting nursing and midwifery regulatory reform was the absence of capacity and resources needed to implement change. Discussion While guidelines on task shifting and recommendations on transforming health professional education exist, this study provides new evidence that countries in the ECSA region face obstacles to adapting their practice and education regulations accordingly. Stakeholders such as CNOs, nursing associations, and academicians have varied and complementary roles with regard to reforming professional practice and education regulation. Conclusion This study provides information for effectively engaging leaders in regulatory reform by clarifying their roles, responsibilities, and activities regarding regulation overall as well as their specific perspectives on task shifting and pre-service reform.

2013-01-01

301

Contribution of Transverse Structures, Magma, and Crustal Fluids to Continental Rift Evolution: The East African Rift in Southern Kenya  

NASA Astrophysics Data System (ADS)

The Magadi rift in southern Kenya formed at ~7 Ma within Proterozoic rocks of the Mozambique orogenic belt, parallel to its contact with the Archean Tanzania craton. The rift is bounded to the west by the ~1600-m-high Nguruman border fault. The rift center is intensely dissected by normal faults, most of which offset ~1.4-0.8 Ma lavas. Current E-W extensional velocities are ~2-4 mm/yr. Published crustal tomography models from the rift center show narrow high velocity zones in the upper crust, interpreted as cooled magma intrusions. Local, surface-wave, and SKS-splitting measurements show a rift-parallel anisotropy interpreted to be the result of aligned melt zones in the lithosphere. Our field observations suggest that recent fault activity is concentrated at the rift center, consistent with the location of the 1998 seismic swarm that was associated with an inferred diking event. Fault zones are pervasively mineralized by calcite, likely from CO2-rich fluids. A system of fault-fed springs provides the sole fluid input for Lake Magadi in the deepest part of the basin. Many of these springs emanate from the Kordjya fault, a 50-km-long, NW-SE striking, transverse structure connecting a portion of the border fault system (the NW-oriented Lengitoto fault) to the current locus of strain and magmatism at the rift center. Sampled springs are warm (44.4°C) and alkaline (pH=10). Dissolved gas data (mainly N2-Ar-He) suggests two-component mixing (mantle and air), possibly indicating that fluids are delivered into the fault zone from deep sources, consistent with a dominant role of magmatism to the focusing of strain at the rift center. The Kordjya fault has developed prominent fault scarps (~150 m high) despite being oblique to the dominant ~N-S fault fabric, and has utilized an en echelon alignment of N-S faults to accommodate its motion. These N-S faults show evidence of sinistral-oblique motion and imply a bookshelf style of faulting to accommodate dextral-oblique motion along the Kordjya fault. Fault relationships imply that the NW-SE transverse structures represent recent activity in the rift, and have locally tilted Late Pleistocene sediments. Given the abundance of N-S striking faults in the rift, the tendency for fault activity along transverse features suggests a change in the rifting driving forces that are likely the result of an interplay between strain localization at the rift center, inherited crustal fabric (NW structures in the Mozambique belt), a possible counterclockwise rotation of stress related to interacting rift segments in southern Kenya, and an active hydrothermal fluid regime that facilitates faulting. By connecting the Lengitoto fault to the rift center, the Kordjya fault has effectively caused the Magadi rift to bypass the Nguruman border fault, which has been rendered inactive and thus no longer a contributor to the rifting process.

Kattenhorn, S. A.; Muirhead, J.; Dindi, E.; Fischer, T. P.; Lee, H.; Ebinger, C. J.

2013-12-01

302

Census and ear-notching of black rhinos (Diceros bicornis michaeli) in Tsavo East National Park, Kenya  

Microsoft Academic Search

This paper updates the status of the black rhino population in Tsavo East National Park (NP). Data were acquired through aerial counts of the black rhino between 3 and 9 October 2010 using three fixed-wing husky aircrafts and a Bell 206L helicopter in an area of about 3,300 km2. Based on previous sightings of rhinos, the area was divided into

S. M. Ngene; E. Bitok; J. Mukeke; F. Gakuya; P. Omondi; K. Kimitei; Y. Watol; J. N. Kimani; B. Okita-Ouma

2011-01-01

303

Aerosol Transport Over Equatorial Africa  

NASA Technical Reports Server (NTRS)

Long-range and inter-hemispheric transport of atmospheric aerosols over equatorial Africa has received little attention so far. Most aerosol studies in the region have focussed on emissions from rain forest and savanna (both natural and biomass burning) and were carried out in the framework of programs such as DECAFE (Dynamique et Chimie Atmospherique en Foret Equatoriale) and FOS (Fires of Savanna). Considering the importance of this topic, aerosols samples were measured in different seasons at 4420 meters on Mt Kenya and on the equator. The study is based on continuous aerosol sampling on a two stage (fine and coarse) streaker sampler and elemental analysis by Particle Induced X-ray Emission. Continuous samples were collected for two seasons coinciding with late austral winter and early austral spring of 1997 and austral summer of 1998. Source area identification is by trajectory analysis and sources types by statistical techniques. Major meridional transports of material are observed with fine-fraction silicon (31 to 68 %) in aeolian dust and anthropogenic sulfur (9 to 18 %) being the major constituents of the total aerosol loading for the two seasons. Marine aerosol chlorine (4 to 6 %), potassium (3 to 5 %) and iron (1 to 2 %) make up the important components of the total material transport over Kenya. Minimum sulfur fluxes are associated with recirculation of sulfur-free air over equatorial Africa, while maximum sulfur concentrations are observed following passage over the industrial heartland of South Africa or transport over the Zambian/Congo Copperbelt. Chlorine is advected from the ocean and is accompanied by aeolian dust recirculating back to land from mid-oceanic regions. Biomass burning products are transported from the horn of Africa. Mineral dust from the Sahara is transported towards the Far East and then transported back within equatorial easterlies to Mt Kenya. This was observed during austral summer and coincided with the dying phase of 1997/98 El Nino.

Gatebe, C. K.; Tyson, P. D.; Annegarn, H. J.; Kinyua, A. M.; Piketh, S.; King, M.; Helas, G.

1999-01-01

304

Connecting the African Superplume to the Anomalous Upper Mantle beneath East Africa and Western Arabia: Results from Adaptively Parameterized P-wave Tomography  

NASA Astrophysics Data System (ADS)

A variety of different plume models have been proposed to explain the pattern of uplift, rifting, and volcanism observed throughout East Africa and western Arabia. Some studies advocate for a single, lower-mantle-originating plume impinging on the lithosphere beneath either southern Ethiopia or Afar. Other studies support multiple upwellings beneath this region, which may originate in the upper or lower mantle. A third proposed explanation is that the rifting and volcanism in East Africa and Arabia are connected to the African Superplume, a large low-velocity anomaly originating near the core-mantle boundary beneath southern Africa. We assess the competing plume models by combining P-wave arrival time data from many new permanent and temporary seismic stations throughout Africa with reprocessed data from the International Seismological Centre. These data are inverted using a global, adaptively parameterized tomography approach that provides improved resolution, especially at mid-mantle depths. We find that neither the single nor multiple lower mantle plume models match our observations, as there is no evidence for any low-velocity plume tails extending into the lower mantle beneath East Africa or Arabia. Additionally, the horizontal resolution of our model is sufficient to distinguish between individual upper mantle plumes, but we do not observe such features. Instead, our results support the African Superplume model and strongly indicate a wide connection (>500 km) between the lower mantle structure beneath southern Africa and the upper mantle structure beneath East Africa and Arabia.

Hansen, S. E.; Nyblade, A.; Benoit, M. H.; Burdick, S. A.; van der Hilst, R. D.

2010-12-01

305

Atmospheric concentrations of polycyclic aromatic hydrocarbons in the watershed of Lake Victoria, East Africa.  

PubMed

In the first study of its kind in Africa, PAHs were measured in high volume (24 h) air samples collected from two sampling stations, at Kakira and Entebbe (KAK and EBB, respectively) within the Lake Victoria watershed in Uganda, to assess source contributions and generate a baseline reference data set for future studies in the East African region. Sampling was conducted over two periods [2000-2004 (KAK and EBB1) and 2008-2010 (EBB2)]. The samples were extracted by accelerated solvent extraction and analyzed for 30 PAHs by GC-MS. The mean total PAH concentrations (ng/m(3)) were found to be 74.3 (range; 19.3-311, N = 39) for KAK, 56.8 (range; 13.3-126, N = 22) for EBB1 and 33.1 (range; 4.91-108, N = 56) for EBB2. The 3-ringed PAHs were the most predominant group with mean concentrations of 35.9 ng/m(3)(EBB1), 30.5 ng/m(3)(KAK) and 23.2 ng/m(3)(EBB2). Naphthalene had an exceptionally high mean concentration (21.9 ng/m(3)) for KAK compared to 0.44 and 0.39 ng/m(3) in EBB1 and EBB2 respectively, likely due to intensive agricultural operations nearby KAK. Principal component and diagnostic ratio analyses showed that the measured levels of PAHs were associated with mixed sources, combustion of petroleum, and biomass being the major sources. PMID:23020709

Arinaitwe, Kenneth; Kiremire, Bernard T; Muir, Derek C G; Fellin, Phil; Li, Henrik; Teixeira, Camilla; Mubiru, Drake N

2012-11-01

306

Spatial Distribution, Sources, and Age of Sedimentary Carbon in Lake Malawi, East Africa  

NASA Astrophysics Data System (ADS)

Currently, the source of organic matter to surface sediments of Lake Malawi (East Africa) is unclear; studies of offshore north-basin cores (363 m to 403 m water depth) have produced conflicting results regarding the proportion of aquatic versus terrestrial organic carbon (OC) contained in these sediments. To address this question, ten multi-cores were recovered from the north basin of Lake Malawi along a transect that follows a major river delta into the lake's deep basin, from 82 m to 386 m water depth. Bulk surface sediment data indicate that while the C/N ratio of organic matter decreases with distance from shore (ranging from 9.8 to 8.3, R2 = 0.58), and stable carbon isotope values become increasingly 13C-depleted (ranging from -21.65 to -25.25, R2 = 0.80), the concentration of OC (wt %) generally increases (ranging from 1.9% to 4.5%, R2 = 0.77). These combined trends suggest substantial carbon contribution from aquatic sources, particularly in the deeper-water, open-lake sites. This trend is supported by preliminary biomarker results. N-alcohols from surface sediments were isolated and grouped into aquatically sourced (C20, C22, and C24) and terrestrially sourced (C28 and C30) fractions for quantification as well as radiocarbon dating. N-alcohol abundance results indicate consistent contribution of terrestrial n-alcohols to surface sediments as distance from shore increases, while aquatic n-alcohol input appears to increase. Preliminary results from compound class specific radiocarbon dating indicate that aquatically sourced n-alcohols isolated from surface sediments may be significantly aged relative to bulk surface sediment.

Kruger, B. R.; Minor, E. C.; Werne, J. P.; Johnson, T. C.

2011-12-01

307

Expanding access to off-grid rural electrification in Africa: An analysis of community-based micro-grids in Kenya  

NASA Astrophysics Data System (ADS)

Community micro-grids have played a central role in increasing access to off-grid rural electrification (RE) in many regions of the developing world, notably South Asia. However, the promise of community micro-grids in sub-Sahara Africa remains largely unexplored. My study explores the potential and limits of community micro-grids as options for increasing access to off-grid RE in sub-Sahara Africa. Contextualized in five community micro-grids in rural Kenya, my study is framed through theories of collective action and combines qualitative and quantitative methods, including household surveys, electronic data logging and regression analysis. The main contribution of my research is demonstrating the circumstances under which community micro-grids can contribute to rural development and the conditions under which individuals are likely to initiate and participate in such projects collectively. With regard to rural development, I demonstrate that access to electricity enables the use of electric equipment and tools by small and micro-enterprises, resulting in significant improvement in productivity per worker (100--200% depending on the task at hand) and a corresponding growth in income levels in the order of 20--70%, depending on the product made. Access to electricity simultaneously enables and improves delivery of social and business services from a wide range of village-level infrastructure (e.g. schools, markets, water pumps) while improving the productivity of agricultural activities. Moreover, when local electricity users have an ability to charge and enforce cost-reflective tariffs and electricity consumption is closely linked to productive uses that generate incomes, cost recovery is feasible. By their nature---a new technology delivering highly valued services by the elites and other members, limited local experience and expertise, high capital costs---community micro-grids are good candidates for elite-domination. Even so, elite control does not necessarily lead to elite capture. Experiences from different micro-grid settings illustrate the manner in which a coincidence of interest between the elites and the rest of members and access to external support can create incentives and mechanisms to enable community-wide access to scarce services, hence mitigating elite capture. Moreover, access to external support was found to increase the likelihood of participation for the relatively poor households. The policy-relevant message from this research is two-fold. In rural areas with suitable sites for micro-hydro power, the potential for community micro-grids appear considerable to the extent that this option would seem to represent "the road not taken" as far as policies and initiatives aimed at expanding RE are concerned in Kenya and other African countries with comparable settings. However, local participatory initiatives not complimented by external technical assistance run a considerable risk of locking rural households into relatively more costly and poor-quality services. By taking advantage of existing and/or building a dense network of local organizations, including micro-finance agencies, the government and development partners can make available to local communities the necessary support---financial, technical or regulatory---essential for efficient design of micro-grids in addition to facilitating equitable distribution of electricity benefits.

Kirubi, Charles Gathu

308

Anthropogenic pressure in East Africa—Monitoring 20 years of land cover changes by means of medium resolution satellite data  

NASA Astrophysics Data System (ADS)

The East Africa IGAD (Intergovernmental Authority on Development in Eastern Africa) region with its great variety of ecological regions experienced major changes during the last decades. This study assesses and quantifies the land cover dynamics in the region by applying a systematic sampling of medium resolution Landsat and DMC Deimos imagery. 445 samples covering about 3% of the study area taken as a box of 20 km × 20 km around each 1 degree latitude and longitude intersects are processed and analyzed. Statistical estimates of land cover change are produced by means of an automatic object-based classification in seven broad classes for the years 1990-2000 and 2000-2010. Figures of change for the East Africa IGAD region are presented and land cover change processes such as loss of natural vegetation and increase of agriculture areas are analyzed. Results highlight the geographical distribution of land cover dynamics and show a 28% increase in agriculture area over the analyzed 20-year time frame. The yearly agriculture area increase rate is around 1.4% for both assessed decades, however a strong increase in yearly deforestation rate - from 0.2% in the first period to 0.4% in the second period - has been observed. These figures are discussed within the context of the drivers of changes and the resulting impact to the natural ecosystem.

Brink, Andreas B.; Bodart, Catherine; Brodsky, Lukas; Defourney, Pierre; Ernst, Celine; Donney, Francois; Lupi, Andrea; Tuckova, Katerina

2014-05-01

309

Analogy between natural gas found in lakes of rift valley system of east Africa and its allied gas in Japan  

SciTech Connect

The Afar triangle in northeastern Ethiopia is where the Red Sea rift, the Carlsberg Ridge of the Indian Ocean, and the Rift Valley system of east Africa meet. In 1979, J. Welhan and H. Craig reported that hydrothermal vents at 21/sup 0/N, on the East Pacific Rise, are discharging turbid waters. Mixtures of the plumes with ambient seawater contain significant amounts of dissolved H/sub 2/ and CH/sub 4/ as well as mantel-derived /sup 3/He-rich helium. The /sup 3/He//sup 4/He ratios of rock samples obtained earlier by J. Lupton and H. Craig from the Mid-Oceanic Ridge, including the Mid-Atlantic Ridge and the east Pacific Rise, are extremely high at an almost constant value of (1.3 +/- 0.2) x 10/sup -5/, which they defined as the MOR-type helium. However, the deep brines of the Red Sea contain about 1,000 times more methane than normal seawater does, according to Gold and Soter in 1980. Much evidence leads us to believe that large amounts of /sup 3/He-rich helium-bearing natural gas have been gushing out in many places of the Rift Valley of east Africa for a long time. In 1980, Gold and Soter stated that Lake Kivu, which occupies part of the East African rift valley, contains 50 million tons of dissolved methane for which there is no adequate microbial source. The Japanese Islands began to separate from the Asian continent during the early Miocene. The early Miocene was characterized by intensive volcanic activity that produced large amounts of pyroclastics and other volcanic rocks, generally called green tuff in Japan. It has been suggested that oil and gas in green tuff is derived from the upper mantle.

Fukuta, O.

1984-09-01

310

Multilingual Education in Kenya: Debunking the Myths  

ERIC Educational Resources Information Center

Arguments that have been advanced against multilingual education in Kenya and Africa in general are not new. Most post-colonial African governments have stuck to the pre-colonial education policies which have no relevance to the present day Africa and were, at best, guided by the interests of the colonial power. Unfortunately, most of the claims…

Orwenjo, Daniel Ochieng

2012-01-01

311

Sodium Stibogluconate (SSG) & Paromomycin Combination Compared to SSG for Visceral Leishmaniasis in East Africa: A Randomised Controlled Trial  

PubMed Central

Background Alternative treatments for visceral leishmaniasis (VL) are required in East Africa. Paromomycin sulphate (PM) has been shown to be efficacious for VL treatment in India. Methods A multi-centre randomized-controlled trial (RCT) to compare efficacy and safety of PM (20 mg/kg/day for 21 days) and PM plus sodium stibogluconate (SSG) combination (PM, 15 mg/kg/day and SSG, 20 mg/kg/day for 17 days) with SSG (20 mg/kg/day for 30 days) for treatment of VL in East Africa. Patients aged 4–60 years with parasitologically confirmed VL were enrolled, excluding patients with contraindications. Primary and secondary efficacy outcomes were parasite clearance at 6-months follow-up and end of treatment, respectively. Safety was assessed mainly using adverse event (AE) data. Findings The PM versus SSG comparison enrolled 205 patients per arm with primary efficacy data available for 198 and 200 patients respectively. The SSG & PM versus SSG comparison enrolled 381 and 386 patients per arm respectively, with primary efficacy data available for 359 patients per arm. In Intention-to-Treat complete-case analyses, the efficacy of PM was significantly lower than SSG (84.3% versus 94.1%, difference?=?9.7%, 95% confidence interval, CI: 3.6 to 15.7%, p?=?0.002). The efficacy of SSG & PM was comparable to SSG (91.4% versus 93.9%, difference?=?2.5%, 95% CI: ?1.3 to 6.3%, p?=?0.198). End of treatment efficacy results were very similar. There were no apparent differences in the safety profile of the three treatment regimens. Conclusion The 17 day SSG & PM combination treatment had a good safety profile and was similar in efficacy to the standard 30 day SSG treatment, suggesting suitability for VL treatment in East Africa. Clinical Trials Registration www.clinicaltrials.gov NCT00255567

Musa, Ahmed; Khalil, Eltahir; Hailu, Asrat; Olobo, Joseph; Balasegaram, Manica; Omollo, Raymond; Edwards, Tansy; Rashid, Juma; Mbui, Jane; Musa, Brima; Abuzaid, Abuzaid Abdalla; Ahmed, Osama; Fadlalla, Ahmed; El-Hassan, Ahmed; Mueller, Marius; Mucee, Geoffrey; Njoroge, Simon; Manduku, Veronica; Mutuma, Geoffrey; Apadet, Lilian; Lodenyo, Hudson; Mutea, Dedan; Kirigi, George; Yifru, Sisay; Mengistu, Getahun; Hurissa, Zewdu; Hailu, Workagegnehu; Weldegebreal, Teklu; Tafes, Hailemariam; Mekonnen, Yalemtsehay; Makonnen, Eyasu; Ndegwa, Serah; Sagaki, Patrick; Kimutai, Robert; Kesusu, Josephine; Owiti, Rhoda; Ellis, Sally; Wasunna, Monique

2012-01-01

312

Phylogeographic Reconstruction of African Yellow Fever Virus Isolates Indicates Recent Simultaneous Dispersal into East and West Africa  

PubMed Central

Yellow fever virus (YFV) is a mosquito-borne flavivirus that is a major public health problem in tropical areas of Africa and South America. There have been detailed studies on YFV ecology in West Africa and South America, but current understanding of YFV circulation on the African continent is incomplete. This inadequacy is especially notable for East and Central Africa, for which the unpredictability of human outbreaks is compounded by limitations in both historical and present surveillance efforts. Sparse availability of nucleotide sequence data makes it difficult to investigate the dispersal of YFV in these regions of the continent. To remedy this, we constructed Bayesian phylogenetic and geographic analyses utilizing 49 partial genomic sequences to infer the structure of YFV divergence across the known range of the virus on the African continent. Relaxed clock analysis demonstrated evidence for simultaneous divergence of YFV into east and west lineages, a finding that differs from previous hypotheses of YFV dispersal from reservoirs located on edges of the endemic range. Using discrete and continuous geographic diffusion models, we provide detailed structure of YFV lineage diversity. Significant transition links between extant East and West African lineages are presented, implying connection between areas of known sylvatic cycling. The results of demographic modeling reinforce the existence of a stably maintained population of YFV with spillover events into human populations occurring periodically. Geographically distinct foci of circulation are reconstructed, which have significant implications for studies of YFV ecology and emergence of human disease. We propose further incorporation of Bayesian phylogeography into formal GIS analyses to augment studies of arboviral disease.

Beck, Andrew; Guzman, Hilda; Li, Li; Ellis, Brett; Tesh, Robert B.; Barrett, Alan D. T.

2013-01-01

313

Climate Change or Urbanization? Impacts on a Traditional Coffee Production System in East Africa over the Last 80 Years  

PubMed Central

Global environmental changes (GEC) such as climate change (CC) and climate variability have serious impacts in the tropics, particularly in Africa. These are compounded by changes in land use/land cover, which in turn are driven mainly by economic and population growth, and urbanization. These factors create a feedback loop, which affects ecosystems and particularly ecosystem services, for example plant-insect interactions, and by consequence agricultural productivity. We studied effects of GEC at a local level, using a traditional coffee production area in greater Nairobi, Kenya. We chose coffee, the most valuable agricultural commodity worldwide, as it generates income for 100 million people, mainly in the developing world. Using the coffee berry borer, the most serious biotic threat to global coffee production, we show how environmental changes and different production systems (shaded and sun-grown coffee) can affect the crop. We combined detailed entomological assessments with historic climate records (from 1929–2011), and spatial and demographic data, to assess GEC's impact on coffee at a local scale. Additionally, we tested the utility of an adaptation strategy that is simple and easy to implement. Our results show that while interactions between CC and migration/urbanization, with its resultant landscape modifications, create a feedback loop whereby agroecosystems such as coffee are adversely affected, bio-diverse shaded coffee proved far more resilient and productive than coffee grown in monoculture, and was significantly less harmed by its insect pest. Thus, a relatively simple strategy such as shading coffee can tremendously improve resilience of agro-ecosystems, providing small-scale farmers in Africa with an easily implemented tool to safeguard their livelihoods in a changing climate.

Jaramillo, Juliana; Setamou, Mamoudou; Muchugu, Eric; Chabi-Olaye, Adenirin; Jaramillo, Alvaro; Mukabana, Joseph; Maina, Johnson; Gathara, Simon; Borgemeister, Christian

2013-01-01

314

Isotopic evidence for neogene hominid paleoenvironments in the Kenya Rift Valley  

SciTech Connect

Bipedality, the definitive characteristic of the earliest hominids, has been regarded as an adaptive response to a transition from forested to more-open habitats in East Africa sometime between 12 million and 5 million years ago. Analyses of the stable carbon isotopic composition ([delta][sup 13]C) of paleosol carbonate and organic matter from the Tugen Hills succession in Kenya indicate that a heterogeneous environment with a mix of C3 and C4 plants has persisted for the last 15.5 million years. Open grasslands at no time dominated this portion of the rift valley. The observed [delta][sup 13]C values offer no evidence for a shift from more-closed C3 environments to C4 grasslands habitats. If hominids evolved in East Africa during the Late Miocene, they did so in an ecologically diverse setting.

Kingston, J.D.; Hill, A. (Yale Univ., New Haven, CT (United States)); Marino, B.D. (Harvard Univ., Cambridge, MA (United States))

1994-05-13

315

Multidimensional Patient-Reported Problems within Two Weeks of HIV Diagnosis in East Africa: A Multicentre Observational Study  

PubMed Central

Objectives We aimed to determine for the first time the prevalence and severity of multidimensional problems in a population newly diagnosed with HIV at outpatient clinics in Africa. Methods Recently diagnosed patients (within previous 14 days) were consecutively recruited at 11 HIV clinics in Kenya and Uganda. Participants completed a validated questionnaire, the African Palliative Outcome Scale (POS), with three underpinning factors. Ordinal logistic regression was used to evaluate risk factors for prevalence and severity of physical, psychological, interpersonal and existential problems. Results There were 438 participants (62% female, 30% with restricted physical function). The most prevalent problems were lack of help and advice (47% reported none in the previous 3 days) and difficulty sharing feelings. Patients with limited physical function reported more physical/psychological (OR?=?3.22) and existential problems (OR?=?1.54) but fewer interpersonal problems (OR?=?0.50). All outcomes were independent of CD4 count or ART eligibility. Conclusions Patients at all disease stages report widespread and burdensome multidimensional problems at HIV diagnosis. Newly diagnosed patients should receive assessment and care for these problems. Effective management of problems at diagnosis may help to remove barriers to retention in care.

Simms, Victoria; Gikaara, Nancy; Munene, Grace; Atieno, Mackuline; Kataike, Jeniffer; Nsubuga, Clare; Banga, Geoffrey; Namisango, Eve; Penfold, Suzanne; Fayers, Peter; Powell, Richard A.; Higginson, Irene J.; Harding, Richard

2013-01-01

316

LLNL Middle East and North Africa and Former Soviet Union Research Database  

SciTech Connect

The Lawrence Livermore National Laboratory (LLNL) Ground-Based Nuclear Explosion Monitoring (GNEM) R and D program has made significant progress populating a comprehensive Seismic Research knowledge Base (SRKB) and deriving calibration parameters for the Middle East and North Africa (ME/NA) and Former Soviet Union (FSU) regions. The LLNL SRKB provides not only a coherent framework in which to store and organize very large volumes of collected seismic waveforms, associated event parameter information, and spatial contextual data, but also provides an efficient data processing/research environment for deriving location and discrimination correction surfaces. The SRKB is a flexible and extensible framework consisting of a relational database (RDB), Geographical Information System (GIS), and associated product/data visualization and data management tools. This SRKB framework is designed to accommodate large volumes of data (over 2 million waveforms from 20,000 events) in diverse formats from many sources in addition to maintaining detailed quality control and metadata. Using the SRKB framework, they are combining travel-time observations, event characterization studies, and regional tectonic models to assemble a library of ground truth information and phenomenology correction surfaces required for support of the ME/NA and FSU regionalization program. Corrections and parameters distilled from the LLNL SRKB provide needed contributions to the DOE Knowledge Base (DOE KB) for the ME/NA and FSU regions and will help improve monitoring for underground nuclear testing. The LLNL research products will facilitate calibration of IMS stations (primary and auxiliary), their surrogates (if not yet installed) and selected gamma stations necessary to complete the above tasks in the ME/NA and FSU regions. They present expanded lookup tables for critical station parameter information (including location and response) and a new integrated and reconciled event catalog dataset including specification of preferred origin solutions and associated phase arrivals for the complete PDE, EDR, CMT, ISC and selected regional catalogs. In addition to an overview of selected datasets and individual research products, they present an overview of their visualization, integration, and organizational processes. Development of these processes and the LLNL SRKB was necessitated by both the very large amount of data and information involved (over 1.5 TB) and the varied data and research result formats utilized. Products contained and organized within the LLNL SRKB are grouped in 5 major categories: (1) Reference contextual information and lookup tables; (2) Ground truth and regionalization data; (3) Event location products; (4) Event identification products; and (5) Visualization and data manipulation processes.

O'Boyle, J.L.; Ruppert, S.D.; Hauk, T.F.; Dodge, D.; Firpo, M.

2000-07-14

317

Sustainable Electricity and Water for Europe, Middle East and North Africa  

NASA Astrophysics Data System (ADS)

Sufficient supply of energy and water are among the key requirements for a sustainable development of nations. Both depend strongly on energy carriers such as oil, gas, coal and uranium which have limited availability and a negative impact on the environment during their use. Within the framework of a series of detailed studies, conventional and renewable energy sources available for electricity production and desalination in Europe, North Africa and the Middle East (EU-MENA) have been analysed. Scenarios have been developed for a sustainable electricity supply based on increased plant and user efficiency, and an accelerated introduction of renewable energy sources. Even if all potential exclusion criteria are applied and only those technologies are considered which will become economically competitive within the next decades, a potential has been identified which exceeds the present electricity demand by orders of magnitude. Solar energy is, in this context, the by far largest resource which will most economically be exploited in centralised solar thermal power plants. In combination with heat storage, these power plants can provide bulk and peak electricity, and can be combined with thermal or reverse osmosis desalination plants. At present, solar thermal power plants with a total capacity exceeding 10 GW are in operation or under construction in Abu Dhabi, Algeria, Egypt, Iran, Israel, Italy, Morocco, Spain and the USA. Ultimately, the increasing electricity demand of EU-MENA can only be secured in conjunction with the required climate and resource protection targets, if all renewable energy sources are exploited where appropriate, and conversion and user efficiency are increased. To utilise the enormous energy resources of the Mediterranean countries, high voltage direct current power lines will have to be built, linking the most abundant and economic resources with the load centres in the North. With electricity losses below 10% over a distance of 3000 km, HVDC lines may provide up to 15% of the total European electricity demand by 2050. For the MENA region, this scenario will provide most promising opportunities: in addition to the export of electricity replacing revenues from dwindling oil and gas resources, solar thermal power plants will provide a major share of their own electricity demands at competitive costs and will provide fresh water by seawater desalination, the latter becoming an urgent requirement over the next decades. This presentation outlines the assumptions and results of the studies which have been performed by an international consortium for 50 EU-MENA countries, as well as the technological and economic implications of the suggested scenario.

Müller-Steinhagen, H.; Trieb, F.

2009-04-01

318

Geochemical and Sedimentological Records of Late Quaternary Climate Change, Lake Tanganyika, Tropical East Africa  

NASA Astrophysics Data System (ADS)

We have analyzed piston core records from Lake Tanganyika (western Tanzania, East African Rift Valley) to investigate possible signals of tropical paleoclimate change during the Late Quaternary. Long paleoclimate records from East Africa are of importance for understanding climatic processes such as the role of solar variability in regulating tropical climates at Milankovitch time scales, and the relationship between abrupt climate changes, migration of Intertropical Convergence Zone, and regional climate variability (Nicholson, 2000). However, records of pre-Holocene climate variability from tropical African lakes (>25ka) are still quite rare. Long records from Lake Tanganyika are of particular interest given the lake's antiquity and its demonstrated potential for producing high resolution (frequently annually laminated) sedimentary records (Cohen et al., 1993). We analyzed physical properties, grain size, total organic carbon, major, minor and trace element variability, and biogenic silica data for a 7.75 m core from the Kalya slope and horst region of central Lake Tanganyika at 640m water depth. Nine 14C dates provide an age model for the core, which spans ~62 cal kyr. Elemental concentrations preserved in Lake Tanganyika sediments record variability in deposition and runoff into the lake basin. Under conditions of rapid erosion, exposure and rapid weathering of bedrock has been shown to generate high concentrations of original silicate minerals enriched in soluble cations such as sodium and potassium, elements that are also biologically conservative. Prior to 40ka cal yr. core sediments are characterized by high magnetic susceptibility, intermediate levels of organic carbon, low to intermediate levels of biogenic silica, and fine grain size, indicative of relatively high precipitation. There is a profound decrease in magnetic susceptibility, a decrease in organic carbon and an increase in grain size at 40ka cal yr, which persists until ~16ka cal yr. Seismic reflection profiles demonstrate the existence of paleodeltas at ~360m below modern lake level that may have formed during this period, although it is unclear whether this deposit represents a Late Quaternary (OIS 2) or earlier (OIS 6) event. Maximum aridity occurred at about 20-20.5ka cal yr, consist with earlier interpretations of lake lowstands (Gasse et al., 1989, Scholz et al., 1997). The late Pleistocene and earliest Holocene sediments in our record are characterized by generally rising magnetic susceptibility, declining organic carbon and biogenic silica, and finer grain size. However during this period there are marked fluctuations in magnetic susceptibility and biogenic silica at millennial time-scales. These indicate intervals of fluctuating precipitation, productivity, and possibly windiness and are particularly prominent during the Pleistocene-Holocene transition. Massive clays, rising magnetic susceptibility, low biogenic silica and low organic carbon mark the early Holocene, indicative of increased rainfall during a regionally wet interval. These sediments are capped by a laminated ooze, indicative of drier conditions and a more stratified water body.

Felton, A. A.; Russell, J. M.; Cohen, A. S.; Baker, M. E.; McGlue, M. M.; Lezzar, K. E.

2005-12-01

319

Tracing the climate and anthropogenic influence on the central Kenya highlands  

NASA Astrophysics Data System (ADS)

Soil and sediment samples were collected from Lakes Rutundu (2500m), Sacred (2200m) and Nkunga (1800m) located on the eastern slopes of Mount Kenya. The samples were mainly composed of silty clay and clay fractions. A suite of geochemical and mineralogical analyses was carried out in order to reconstruct the climatic and anthropogenic influence on the highland ecosystem using modern and palaeodata. These analyses included total carbon (TC), Total Nitrogen (TN), Stable carbon and Nitrogen isotopes, elemental composition and organic chemistry. Indications are that the central Kenya highland ecotones have distinct responses to definite triggers of wet and dry climatic phases, which are marked alongside wide spread anthropogenic influence on a climate gradient. The changes observed provide insight into the collective influence of the biogeochemical cycle during the late Holocene in the east Africa highland where not much information has been published earlier.

Omuombo, Christine; Olago, Daniel; Williamson, David; Huguet, Arnaud

2013-04-01

320

Africa.  

ERIC Educational Resources Information Center

Although the activities in this unit are designed primarily for students in the intermediate grades, the document's text, illustrations, and bibliographic references are suitable for anyone interested in learning about Africa. Following a brief introduction and map work, the document is arranged into six sections. Section 1 traces Africa's history…

Happel, Sue; Loeb, Joyce

321

Africa  

NSDL National Science Digital Library

Africa is the companion Website to a PBS series being broadcast September 9 - October 28, 2001. The Photoscope section has five photo essays, on AIDS, Conflict, Urban Africa, Environment, and Women. Urban Africa presents views of contrasts, like a man cutting lettuce in a field under a billboard advertising Internet access, an aerial view of shacks in Cape Town's Philippi Township, and a well-dressed woman bargaining for vegetables in a street market in Lagos. Also included are Africa Challenge, a history game; Africa for Kids; Teacher Tools, including lesson plans; and About the Series, with descriptions of episodes, series profiles (what has happened to people featured in the shows), a link to hear the theme music, and more.

2001-01-01

322

Orbital- versus glacial-mode forcing of tropical African climate: Results of scientific drilling in Lake Malawi, East Africa  

NASA Astrophysics Data System (ADS)

Lake Malawi extends from 9-14 degrees S within the East African Rift Valley, and at 700 m deep, contains more than 20 percent of the surface water on the African continent. In 2005 the Lake Malawi Scientific Drilling Project drilled 7 holes at two sites in the lake, recovering a continuous sediment record that samples much of the Quaternary. Detailed studies completed to date on sediments deposited during the past 145 ka indicate periods of severe aridity at precessional frequency between 135 and 75 ka, when the lake's water volume was periodically reduced by at least 95 percent. These dramatic drops in lake level (more than 550 m), signifying markedly arid conditions in the catchment, are documented in sediment lithology (decreased organic carbon content and increased authigenic carbonate content during severe lowstands), aquatic microfossils (appearance of a littoral ostracode fauna, and saline/alkaline lake diatom flora during extreme low lake stages), as well as in dramatic reductions in catchment pollen production. These intervals of pronounced tropical African aridity in the early late-Pleistocene were much more severe than the Last Glacial Maximum, and are consistent with sediment records from Lakes Tanganyika (East Africa) and Bosumtwi (West Africa). In all three lakes a major rise in water levels and a shift to more humid conditions is observed after ~70 ka. The transition to wetter, more stable conditions coincides with the relaxation of orbital eccentricity and a reduction in the amplitude of precession. The observed climate mode switch to decreased environmental variability is consistent with terrestrial and marine records from in and around tropical Africa, but these new drill cores provide evidence for dramatically drier conditions prior to 70 ka that have not as yet been detected in marine sediment records. Such climate change may have stimulated the expansion and migrations of early modern human populations.

Scholz, C. A.; Cohen, A. S.; Johnson, T. C.; King, J. W.; Brown, E. T.; Lyons, R. P.; Stone, J. R.; Beuning, K. R.

2007-12-01

323

Status and ecosystem interactions of the invasive Louisianan red swamp crayfish Procambarus clarkii in East Africa  

Microsoft Academic Search

There are no indigenous crayfish in continental Africa although there are indigenous crayfish on the island of Madagascar\\u000a (Hobbs 1988). However, various non-indigenous North American and Australian crayfish have been introduced to continental Africa\\u000a since the 1970s, notably the Louisianan red swamp crayfish Procambarus clarkii (Girard). This is a relatively large, prolific, aggressive, burrowing crayfish (Hobbs et al. 1989 quoted

John Foster; David Harper

324

The Episode of Genetic Drift Defining the Migration of Humans out of Africa Is Derived from a Large East African Population Size  

PubMed Central

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.

Elnour, Mohamed Ali; Isabirye, Dan; Okello, John; Hussien, Ayman; Kwiatksowski, Dominic; Hirbo, Jibril; Tishkoff, Sara; Ibrahim, Muntaser E.

2014-01-01

325

Westward dipping upper mantle structure beneath eastern Africa: Is it part of the African Superplume?  

NASA Astrophysics Data System (ADS)

The African Superplume is a large region of low seismic wave speeds in the lower mantle under Africa that has long been recognized as one of the most prominent upwellings in the mantle, and that possibly holds the key to unraveling the dynamics of mantle convection. Some global seismic tomography models suggest that anomalous structure in the lower mantle beneath southern Africa links with anomalous upper mantle structure under eastern Africa. The region in the mid-mantle where the regions of anomalous upper and lower mantle meet is under the western side of the East African Plateau. We present regional P and S tomographic images from Ethiopia, Kenya, and Tanzania showing a low velocity zone in the upper mantle at depths below 150 km dipping to the west. Results from stacking receiver functions for Tanzania and Ethiopia indicate that the westward dipping low velocity zone continues into and perhaps through the transition zone, possibly linking with anomalous lower mantle structure under central Africa at mid-mantle depths. The similarity between the regional and global tomographic images suggests that anomalous upper mantle structure beneath eastern Africa may indeed be part of the African Superplume. A westward dipping low velocity zone in the upper mantle along the entire length of the Eastern Branch of the East African rift system (Ethiopia, Kenya and Tanzania) is not easy to explain with plume head models that have been frequently invoked to explain Cenozoic rifting, volcanism and uplift in eastern Africa.

Nyblade, A.; Park, Y.; Benoit, M.

2006-05-01

326

Mapping crustal heterogeneity using Lg propagation efficiency throughout the Middle East, Mediterranean, Southern Europe and Northern Africa  

USGS Publications Warehouse

In this paper we describe a technique for mapping the lateral variation of Lg characteristics such as Lg blockage, efficient Lg propagation, and regions of very high attenuation in the Middle East, North Africa, Europe and the Mediterranean regions. Lg is used in a variety of seismological applications from magnitude estimation to identification of nuclear explosions for monitoring compliance with the Comprehensive Nuclear-Test-Ban Treaty (CTBT). These applications can give significantly biased results if the Lg phase is reduced or blocked by discontinuous structure or thin crust. Mapping these structures using quantitative techniques for determining Lg amplitude attenuation can break down when the phase is below background noise. In such cases Lg blockage and inefficient propagation zones are often mapped out by hand. With our approach, we attempt to visually simplify this information by imaging crustal structure anomalies that significantly diminish the amplitude of Lg. The visualization of such anomalies is achieved by defining a grid of cells that covers the entire region of interest. We trace Lg rays for each event/ station pair, which is simply the great circle path, and attribute to each cell a value equal to the maximum value of the Lg/P-coda amplitude ratio for all paths traversing that particular cell. The resulting map, from this empirical approach, is easily interpreted in terms of crustal structure and can successfully image small blockage features often missed by analysis of raypaths alone. This map can then be used to screen out events with blocked Lg prior to performing Q tomography, and to avoid using Lg-based methods of event identification for the CTBT in regions where they cannot work. For this study we applied our technique to one of the most tectonically complex regions on the earth. Nearly 9000 earthquake/station raypaths, traversing the vast region comprised of the Middle East, Mediterranean, Southern Europe and Northern Africa, have been analyzed. We measured the amplitude of Lg relative to the P-coda and mapped the lateral variation of Lg propagation efficiency. With the relatively dense coverage provided by the numerous crossing paths we are able to map out the pattern of crustal heterogeneity that gives rise to the observed character of Lg propagation. We observe that the propagation characteristics of Lg within the region of interest are very complicated but are readily correlated with the different tectonic environments within the region. For example, clear strong Lg arrivals are observed for paths crossing the stable continental interiors of Northern Africa and the Arabian Shield. In contrast, weakened to absent Lg is observed for paths crossing much of the Middle East, and Lg is absent for paths traversing the Mediterranean. Regions that block Lg transmission within the Middle East are very localized and include the Caspian Sea, the Iranian Plateau and the Red Sea. Resolution is variable throughout the region and strongly depends on the distribution of seismicity and recording stations. Lg propagation is best resolved within the Middle East where regions of crustal heterogeneity on the order of 100 km are imaged (e.g., South Caspian Sea and Red Sea). Crustal heterogeneity is resolvable but is poorest in seismically quiescent Northern Africa.

McNamara, D. E.; Walter, W. R.

2001-01-01

327

Manpower (To Include Women) and Military Establishments in the Middle East and North Africa.  

National Technical Information Service (NTIS)

This study, addresses a facet of security and military capabilities in the Middle East by examing the current and projected availability of military manpower in ten select countries: Algeria, Egypt, Iran, Iraq, Israel, Jordan, Libya, Morocco, Saudi Arabia...

1984-01-01

328

Metasomatized lithospheric mantle beneath Turkana depression in southern Ethiopia (the East Africa Rift): geochemical and Sr–Nd–Pb isotopic characteristics  

Microsoft Academic Search

Mantle xenoliths entrained in Quaternary alkaline basalts from the Turkana Depression in southern Ethiopia (the East Africa Rift) were studied for their geochemical and Sr–Nd–Pb isotopic compositions to constrain the evolution of the lithosphere. The investigated mantle xenoliths are spinel lherzolites in composition with a protogranular texture. They can be classified into two types: anhydrous and hydrous spinel lherzolites; the

Ryuichi Shinjo; Risa Matsumura

2011-01-01

329

A comparison of the vegetation response to rainfall in the Sahel and East Africa, using normalized difference vegetation index from NOAA AVHRR  

Microsoft Academic Search

This article presents the results of a study of the relationship between rainfall and Normalized Difference Vegetation Index (NDVI) in East Africa and the Sahel. Monthly data for the years 1982 to 1985 have been analyzed. We have evaluated NDVI-rainfall relationships by vegetation type, using the major formations described by White (1983). In the article, a comparison of the differential

Sharon E. Nicholson; Michael L. Davenport; Ada R. Malo

1990-01-01

330

Do School Incentives and Accountability Measures Improve Skills in the Middle East and North Africa? The Cases of Jordan and Tunisia  

ERIC Educational Resources Information Center

There is general agreement that skill-enhancing school reforms in the Middle East and North Africa (MENA) region are necessary for economic, political and social reasons. Using student-level data from Jordan and Tunisia, this study assesses the relationship between skills and the following school incentive and accountability measures: pedagogical…

Shafiq, M. Najeeb

2011-01-01

331

Indian Ocean climate event brings floods to East Africa's lakes and the Sudd marsh  

Microsoft Academic Search

During an El Niño, the expected rainfall increase over most of the Lake Victoria catchment area is ~15-25%. However, due to anomalous warming of the western equatorial Indian Ocean during 1997, strong convection developed over parts of the Horn and eastern Africa. This resulted in a much larger 20-160% precipitation excess during the ``short rainy'' season. Satellite radar altimetry data

Charon Birkett; Ragu Murtugudde; Tony Allan

1999-01-01

332

Integration of transhumant pastoralism and irrigated agriculture in semi-arid East Africa  

Microsoft Academic Search

Agricultural development projects in the fertile and most well-watered areas of arid and semiarid Africa usually deny access to nomadic pastoralists whose production system and livelihood depend upon such areas in the dry season and during frequent droughts. The result can be degradation of range resources through overgrazing, and greater vulnerability of pastoralists. Recent calls for compatible land use schemes

Jon D. Unruh

1990-01-01

333

RAPD DNA fingerprints and terpenoids: clues to past migrations of Juniperus in Arabia and east Africa  

Microsoft Academic Search

Random amplified polymorphic DNAs (RAPDs) and leaf volatile terpenoids were used to compare junipers from Abha, Saudi Arabia with J. excelsa from Greece and J. procera from Addis Ababa, Ethiopia. Both the RAPDs and terpenoids clearly identified the Abha juniper as J. procera. The migration and evolution of J. excelsa or pre-J. excelsa junipers southward from Asia Minor into Africa

R. P. Adams; T. Demeke; H. A. Abulfatih

1993-01-01

334

Reference, Coherence and Complexity in Students' Academic Writing: Examples from Cameroon and East-Africa Corpus  

ERIC Educational Resources Information Center

This contribution discusses problems of students' academic writing in Africa. It sketches the wide field of English for Academic Purposes (EAP) and argues that reference, coherence and complexity are key concepts for evaluating student writing at university level. It uses material from African corpora to substantiate this claim and to illustrate…

Schmied, Josef; Nkemleke, Daniel

2011-01-01

335

Women in higher education in agriculture with reference to selected countries in East and Southern Africa  

Microsoft Academic Search

In Africa, the continued under-representation of women in education is particularly severe, especially in tertiary level programs relevant to agricultural development. The underlying premises of this paper are, firstly, that African agricultural development would be better served by an increase in the number of well-trained women leaders in agricultural research, extension, training and policy. Secondly, that there are currently very

D. G. Acker; E. L. McBreen; S. Taylor

1998-01-01

336

LANDSAT image studies as applied to petroleum exploration in Kenya  

NASA Technical Reports Server (NTRS)

The Chevron-Kenya oil license, acquired in 1972, covers an area at the north end of the Lamu Embayment. Immediately after acquisition, a photogeologic study of the area was made followed by a short field inspection. An interpretation of LANDSAT-1 images as a separate attempt to improve geological knowledge was completed. The method used in the image study, the multispectral characteristics of rock units and terrain, and the observed anomalous features as seen in the LANDSAT imagery are described. It was found that the study helped to define the relationship of the Lamu Embayment and its internal structure with surrounding regional features, such as the East Africa rifting, the Rudolf Trough, the Bur Acaba structural ridge, and the Ogaden Basin.

Miller, J. B.

1975-01-01

337

Nd and Sr isotope systematics of Shombole volcano, East Africa, and the links between nephelinites, phonolites, and carbonatites  

SciTech Connect

Nd and Sr isotope compositions of nephelinites, carbonatites, and phonolites from Shombole, a Pliocene volcano in East Africa, show that the phonolites cannot be derived by simple fractional crystallization of nephelinite magma. For a given initial {sup 87}Sr/{sup 86}Sr ratio, {sup 143}Nd/{sup 144}Nd is lower in most phonolites than in the nephelinites and carbonatites. Interaction between nephelinitic magma and lower-crustal granulites can account for these differences. The similar ranges in isotopic composition of the carbonatites and nephelinites are consistent with repeated melting events involving heterogeneous mantle. The carbonatites could have formed by immiscibility with nephelinite magma or by direct partial melting of the same mantle source(s) as the nephelinites.

Bell, K. (Carleton Univ., Ottawa, Ontario (Canada)); Peterson, T. (Geological Survey of Canada, Ottawa, Ontario (Canada))

1991-06-01

338

Grid search modeling of receiver functions: Implications for crustal structure in the Middle East and North Africa  

SciTech Connect

A grid search is used to estimate average crustal thickness and shear wave velocity structure beneath 12 three-component broadband seismic stations in the Middle East, North Africa, and nearby regions. The crustal thickness in these regions is found to vary from a minimum of 8.0{plus_minus}1.5&hthinsp;km in East Africa (Afar) region to possibly a maximum of 64{plus_minus}4.8&hthinsp;km in the lesser Caucasus. Stations located within the stable African platform indicate a crustal thickness of about 40 km. Teleseismic three-component waveform data produced by 165 earthquakes are used to create receiver function stacks for each station. Using a grid search, we have solved for the optimal and most simple shear velocity models beneath all 12 stations. Unlike other techniques (linearized least squares or forward modeling), the grid search methodology guarantees that we solve for the global minimum within our defined model parameter space. Using the grid search, we also qualitatively estimate the least number of layers required to model the observed receiver functions{close_quote} major seismic phases (e.g., PS{sub Moho}). A jackknife error estimation method is used to test the stability of our receiver function inversions for all 12 stations in the region that had recorded a sufficient number of high-quality broadband teleseismic waveforms. Five of the 12 estimates of crustal thicknesses are consistent with what is known of crustal structure from prior geophysical work. Furthermore, the remaining seven estimates of crustal structure are in regions for which previously there were few or no data about crustal thickness. {copyright} 1998 American Geophysical Union

Sandvol, E.; Seber, D.; Calvert, A.; Barazangi, M. [Institute for the Study of the Continents, Cornell University, Ithaca, New York (United States)] [Institute for the Study of the Continents, Cornell University, Ithaca, New York (United States)

1998-11-01

339

Holistic view to integrated climate change assessment and extreme weather adaptation in the Lake Victoria Basin East Africa  

NASA Astrophysics Data System (ADS)

Extreme weather events have been the leading cause of disasters and damage all over the world.The primary ingredient to these disasters especially floods is rainfall which over the years, despite advances in modeling, computing power and use of new data and technologies, has proven to be difficult to predict. Also, recent climate projections showed a pattern consistent with increase in the intensity and frequency of extreme events in the East African region.We propose a holistic integrated approach to climate change assessment and extreme event adaptation through coupling of analysis techniques, tools and data. The Lake Victoria Basin (LVB) in East Africa supports over three million livelihoods and is a valuable resource to five East African countries as a source of water and means of transport. However, with a Mesoscale weather regime driven by land and lake dynamics,extreme Mesoscale events have been prevalent and the region has been on the receiving end during anomalously wet years in the region. This has resulted in loss of lives, displacements, and food insecurity. In the LVB, the effects of climate change are increasingly being recognized as a significant contributor to poverty, by its linkage to agriculture, food security and water resources. Of particular importance are the likely impacts of climate change in frequency and intensity of extreme events. To tackle this aspect, this study adopted an integrated regional, mesoscale and basin scale approach to climate change assessment. We investigated the projected changes in mean climate over East Africa, diagnosed the signals of climate change in the atmosphere, and transferred this understanding to mesoscale and basin scale. Changes in rainfall were analyzed and similar to the IPCC AR4 report; the selected three General Circulation Models (GCMs) project a wetter East Africa with intermittent dry periods in June-August. Extreme events in the region are projected to increase; with the number of wet days exceeding the 90% percentile of 1981-2000 likely to increase by 20-40% in the whole region. We also focused on short-term weather forecasting as a step towards adapting to a changing climate. This involved dynamic downscaling of global weather forecasts to high resolution with a special focus on extreme events. By utilizing complex model dynamics, the system was able to reproduce the Mesoscale dynamics well, simulated the land/lake breeze and diurnal pattern but was inadequate in some aspects. The quantitative prediction of rainfall was inaccurate with overestimation and misplacement but with reasonable occurrence. To address these shortcomings we investigated the value added by assimilating Advanced Microwave Scanning Radiometer (AMSR-E) brightness temperature during the event. By assimilating 23GHz (sensitive to water) and 89GHz (sensitive to cloud) frequency brightness temperature; the predictability of an extreme rain weather event was investigated. The assimilation through a Cloud Microphysics Data Assimilation (CMDAS) into the weather prediction model considerably improved the spatial distribution of this event.

Mutua, F.; Koike, T.

2013-12-01

340

Ecology and geography of avian influenza (HPAI H5N1) transmission in the Middle East and northeastern Africa  

PubMed Central

Background The emerging highly pathogenic avian influenza strain H5N1 ("HPAI-H5N1") has spread broadly in the past decade, and is now the focus of considerable concern. We tested the hypothesis that spatial distributions of HPAI-H5N1 cases are related consistently and predictably to coarse-scale environmental features in the Middle East and northeastern Africa. We used ecological niche models to relate virus occurrences to 8 km resolution digital data layers summarizing parameters of monthly surface reflectance and landform. Predictive challenges included a variety of spatial stratification schemes in which models were challenged to predict case distributions in broadly unsampled areas. Results In almost all tests, HPAI-H5N1 cases were indeed occurring under predictable sets of environmental conditions, generally predicted absent from areas with low NDVI values and minimal seasonal variation, and present in areas with a broad range of and appreciable seasonal variation in NDVI values. Although we documented significant predictive ability of our models, even between our study region and West Africa, case occurrences in the Arabian Peninsula appear to follow a distinct environmental regime. Conclusion Overall, we documented a variable environmental "fingerprint" for areas suitable for HPAI-H5N1 transmission.

Williams, Richard AJ; Peterson, A Townsend

2009-01-01

341

Single-nucleotide polymorphisms for high-throughput genotyping of Anopheles arabiensis in East and southern Africa.  

PubMed

Anopheles arabiensis Patton is one of the principal vectors of malaria in sub-Saharan Africa, occupying a wide variety of ecological zones. This species is increasingly responsible for malaria transmission in Africa and is becoming the dominant vector species in some localities. Despite its growing importance, little is known about genetic polymorphisms in this species. Multiple sequences of various gene fragments from An. arabiensis isolates from Cameroon were obtained from GenBank. In total, 20 gene fragments containing single-nucleotide polymorphisms (SNPs) at moderate density were selected for direct sequencing from field collected specimens from Tanzania and Zambia. We obtained 301 SNPs in total from the 20 gene fragments, 60 of which were suitable for Illumina GoldenGate SNP genotyping. A greater number of SNPs (n = 185) was suitable for analysis using Sequenom iPLEX, an alternative high-throughput genotyping technology using mass spectrometry. An SNP was present every 59 (+/- 44.5) bases on average. Overall, An. arabiensis from Tanzania and Zambia are genetically closer (mean F(ST) = 0.075) than either is to populations in Cameroon (F(ST, TZ-CM) = 0.250, F(ST,ZA-CM) = 0.372). A fixed polymorphism between East/southern and Central Africa was identified on AGAP000574, a gene on the X chromosome. We have identified SNPs in natural populations of An. arabiensis. SNP densities in An. arabiensis were higher than Anopheles gambiae s.s., suggesting a greater challenge in the development of high-throughput SNP analysis for this species. The SNP markers provided in this study are suitable for a high-throughput genotyping analysis and can be used for population genetic studies and association mapping efforts. PMID:22493848

Lee, Yoosook; Seifert, Stephanie N; Fornadel, Christen M; Norris, Douglas E; Lanzaro, Gregory C

2012-03-01

342

Single-Nucleotide Polymorphisms for High-Throughput Genotyping of Anopheles arabiensis in East and Southern Africa  

PubMed Central

Anopheles arabiensis Patton is one of the principal vectors of malaria in sub-Saharan Africa, occupying a wide variety of ecological zones. This species is increasingly responsible for malaria transmission in Africa and is becoming the dominant vector species in some localities. Despite its growing importance, little is known about genetic polymorphisms in this species. Multiple sequences of various gene fragments from An. arabiensis isolates from Cameroon were obtained from GenBank. In total, 20 gene fragments containing single-nucleotide polymorphisms (SNPs) at moderate density were selected for direct sequencing from field collected specimens from Tanzania and Zambia. We obtained 301 SNPs in total from the 20 gene fragments, 60 of which were suitable for Illumina GoldenGate SNP genotyping. A greater number of SNPs (n = 185) was suitable for analysis using Sequenom iPLEX, an alternative high-throughput genotyping technology using mass spectrometry. An SNP was present every 59 (±44.5) bases on average. Overall, An. arabiensis from Tanzania and Zambia are genetically closer (mean FST = 0.075) than either is to populations in Cameroon (FST, TZ-CM = 0.250, FST, ZA-CM = 0.372). A fixed polymorphism between East/southern and Central Africa was identiidentified on AGAP000574, a gene on the X chromosome. We have identiidentified SNPs in natural populations of An. arabiensis. SNP densities in An. arabiensis were higher than Anopheles gambiae s.s., suggesting a greater challenge in the development of high-throughput SNP analysis for this species. The SNP markers provided in this study are suitable for a high-throughput genotyping analysis and can be used for population genetic studies and association mapping efforts.

LEE, YOOSOOK; SEIFERT, STEPHANIE N.; FORNADEL, CHRISTEN M.; NORRIS, DOUGLAS E.; LANZARO, GREGORY C.

2014-01-01

343

East Africa's pastoralist emergency: is climate change the straw that breaks the camel's back?  

PubMed

The global warming trend of climate change is having severe adverse effects on the livelihoods of the Turkana pastoralists of northwestern Kenya. Care has to be taken in making assertions about the impact of climate change. The biggest effects may come not from lower average rainfall but from a widening of the standard deviation as weather extremes become more frequent. In a region already prone to drought, disease and conflict, climate change, access to modern weapons and new viral livestock diseases are now overwhelming pastoralists' coping capacity and deepening the region's roughly 30-year dependency on famine relief. This article examines the livelihood strategies of the Turkana and several poverty reduction programmes currently established, while addressing the reality that traditional pastoralism may no longer be a viable livelihood option, given the effects of climate change, disease and the ensuing conflict over diminishing resources. The findings conclude that the future for traditional Turkana pastoralists is dismal because they continue to depend on an environment that may no longer support them. Humanitarians are recommended to shift their focus to advocate and invest in alternative livelihood strategies that generate economic independence and help the Turkana adapt to their changing environment. PMID:21506297

Blackwell, P J

2010-01-01

344

Role of land surface processes in monsoon development: East Asia and West Africa  

Microsoft Academic Search

Evidence is presented that exchanges of water and energy between the vegetation and the atmosphere play an important role in east Asian and West African monsoon development and are among the most important mechanisms governing the development of the monsoon. The results were obtained by conducting simulations for five months of 1987 using a general circulation model (GCM) coupled with

Yongkang Xue; H.-M. H. Juang; W.-P. Li; S. Prince; R. DeFries; Y. Jiao; R. Vasic

2004-01-01

345

Origin of the Superflock of Cichlid Fishes from Lake Victoria, East Africa  

Microsoft Academic Search

Lake Victoria harbors a unique species-rich flock of more than 500 endemic haplochromine cichlid fishes. The origin, age, and mechanism of diversification of this extraordinary radiation are still debated. Geological evidence suggests that the lake dried out completely about 14,700 years ago. On the basis of phylogenetic analyses of almost 300 DNA sequences of the mitochondrial control region of East

Erik Verheyen; Walter Salzburger; Jos Snoeks; Axel Meyer

2003-01-01

346

Lettowia, a new genus of Vernonieae from East Africa (Asteraceae).  

PubMed

A new genus, Lettowia H. Rob. & Skvarla is named for the single East African species originally described as Vernonia nyassae Oliv. Its pollen is lophate and triporate, with a perforated tectum restricted to the muri. The new genus is placed near Vernoniastrum in the subtribe Erlangeinae. PMID:24198711

Robinson, Harold; Skvarla, John J

2013-01-01

347

Oil and the economic geography of the Middle East and North Africa  

SciTech Connect

This book gives us the opportunity to follow the development of the field of economic geography as applied to the Middle East during the past half century. The materials are arranged under the following three headings: Geography and Petroleum: Boundaries and Boundary Disputes: and Social Geography.

Kortepeter, C.M. (New York Univ., NY (United States))

1990-01-01

348

Mapping of C 4 plant input from North West Africa into North East Atlantic sediments  

Microsoft Academic Search

Mapping the abundance of 13C in leaf-wax components in surface sediments recovered from the seafloor off northwest Africa (0–35°N) reveals a clear pattern of ?13C distribution, indicating systematic changes in the proportions of terrestrial C3 and C4 plant input. At 20°N latitude, we find that isotopically enriched products characteristic of C4 plants account for more than 50% of the terrigenous

Yongsong Huang; Lydie Dupont; Michael Sarnthein; John M. Hayes; Geoffrey Eglinton

2000-01-01

349

Revisiting a hoary chestnut: the nature of early cattle domestication in North-East Africa  

PubMed Central

Summary It has been almost three decades since the Wendorf & Schild-Andrew Smith debate over the timing and location of domesticated cattle in North Africa reached its climax. The time is now appropriate for a review of the old models in light of subsequent anatomical and genetic data which have come to light. This article summarises the main issues and models, and attempts to provide suggestions for future investigations.

Brass, Michael

2013-01-01

350

77 FR 66582 - Notice of Request for Information for the Proposed United States-East African Community...  

Federal Register 2010, 2011, 2012, 2013

...send comments to Ludwika Alvarez, East Africa Desk Officer, Office of Africa...INFORMATION CONTACT: Ludwika Alvarez, East Africa Desk Officer, Office of Africa...American Chambers of Commerce in East Africa), [[Page 66583

2012-11-06

351

Lake level change and total water discharge in East Africa Rift Valley from satellite-based observations  

NASA Astrophysics Data System (ADS)

The measurement of total basin water discharge is important for understanding the hydrological and climatologic issues related to the water and energy cycles. Climatic extreme events are normal climatic occurrences in Africa. For example, extensive droughts are regular features in the last few decades in parts of East Africa, which suffers from a lack of in situ observations as well as a lack of regional hydrological models. In this study, multi-disciplinary different types of space-borne observations and global hydrological models are used to study total water discharge in the Great Rift Valley of East Africa (i.e. Lakes Victoria, Tanganyika, and Malawi) from January 2003 to December 2012. The data include the following: (1) total water storage (TWS) variations from Gravity Recovery and Climate Experiment (GRACE), (2) the lake level variations from Satellite Alimetric data, (3) rainfall from Tropical Rainfall Measurement Mission (TRMM) products, (4) soil moisture from WaterGAP Global Hydrology Model (WGHM), and (5) water fluxes from Global Land Data Assimilation System (GLDAS). Results show that a significant decline in the average lake level is found for all of the three lakes between 2003 and 2006. GRACE TWS variations of the whole basin area show the same pattern of variation as the average lake level variations estimated from Altimetric data. The TWS in the basin area of Lakes Victoria and Malawi is governed by the surface water stored in each lake itself, while for Lake Tanganyika, it is governed by both surface water and the soil moisture content in the basin area. Furthermore, the effect of rainfall on TWS is also studied. A phase lag of ~ 2 months is found between TRMM rainfall and GRACE TWS (generally, rainfall precedes the GRACE TWS) for the three lakes. In addition, the regional evapotranspiration ET is estimated from the water balance equation using GRACE land-water solutions, rainfall data from TRMM and runoff values obtained as a fraction of rainfall. It is found that the computed ET represents approximately 90% of the rainfall over the study region.

Hassan, Ayman A.; Jin, Shuanggen

2014-06-01

352

Along-dip variations of structural style in the Somali Basin deep-water fold and thrust belt (East Africa)  

NASA Astrophysics Data System (ADS)

Continental passive margins are place of extended slope-failure phenomena, which can lead to the formation of gravity-driven deep-water fold and thrust belts (DW-FTBs), in regions where no far-field compressional stress is active. These giant geological features, which are confined to the sedimentary section, consist of extensional-compressional linked systems detached over a common décollement, generally salt or shales. The continental passive margin of northern Kenya and southern Somalia is an excellent and relatively unexplored site for recognizing and understanding the DW-FTBs originated over a regional shale décollement. In this study we have interpreted a 2D seismic data-set of the 1980s, hosted by Marine Geoscience Data System at Lamont-Doherty Earth Observatory of Columbia University (http://www.marine-geo.org), and recently reprocessed by ENI, in order to investigate the structural style of a DW-FTB developed offshore of northern Kenya and southern Somalia (Somali Basin). This region records the oldest sedimentary section of the Indian Ocean since the breakup of Gondwana began in the Middle-Lower Jurassic separating Madagascar from Africa. From the Upper Cretaceous to at least the Lower Miocene, the margin has been characterized by gravitational collapse leading to the formation of a DW-FTB extending more than 400 km along-strike. The northern portion of the DW-FTB is about 150 km wide, whilst in the southern portion is few tens of km wide. We analysed the northern portion along a regional seismic section. Our study represents the first detailed structural interpretation of this DW-FTB since its discovery in the 1980s. The good quality of the available reprocessed seismic data has allowed us to identify remarkable along-dip variations in the structural style. The basal detachment constantly deepens landward, in agreement with a prevailing gravity-spreading deformation process (as in the case of the Niger Delta). On the seismic data are not visible, as expected, relevant extensional growth faults and normal faults, which can balance the significant amount of shortening of the compressional domain. We recognised four sectors, characterized by different structural styles and amount of shortening. Moving from the ocean towards the land, they are: i) a series of imbricate thrusts with basinward vergence, forming a critical taper; ii) basinward stacked horses forming a duplex-like system; iii) double verging, out-of syncline thrusts, transporting bowl-shaped syn-kinematic basins; and iv) symmetric, diapir-like detachment folds, likely cored by poorly compacted mobile shales. We hypothesise that these strong and often abrupt variations could be related to: i) lateral differences in the stratigraphy of the sedimentary successions involved in the deformation; ii) time and space variations of the sediment supply along the continental slope.

Cruciani, Francesco; Rinaldo Barchi, Massimiliano

2014-05-01

353

Fossil marl prairie as indicator for aridification and coastal uplift in equatorial East Africa during the last glaciation  

NASA Astrophysics Data System (ADS)

Facies analyses of Pleistocene deposits from southern coastal Tanzania (Lindi District) document that sediments have formed in a wetland that developed on a coastal terrace in front of the Lindi Fracture Zone. The exposed sedimentary succession reveals one transgression/regression cycle. A rising relative sea level is indicated by back-stepping tidal flats. The overlying palustrine limestones were precipitated in a marl prairie that developed due to falling relative sea level. In marl prairies, carbonate precipitates seasonally in barely flooded grasslands within periphyton mats. Despite the special mode of carbonate production descriptions of the sedimentary facies are cursory because marl prairies are so far reported only from the Recent Everglades (Florida/USA) where they produce an unspectacular calcite mud. The Pleistocene marl prairie from Africa is the first fossil example and, in contrast to the Everglades marl prairies, the periphyton is excellently preserved because of a better calcification of the associated cyanobacteria. The unique preservation allows us to characterize a marl prairie facies in great detail for the first time. Located at the interface between land and sea marl prairies are sensitive to changes in water balance and a useful recorder for climate and sea level changes. Radiocarbon dating of Assiminea gastropods from the studied sediments reveal the emergence of the coastal terrace started at ~44 ka BP. This coincides with a eustatic sea level fall prior to the last glaciation maximum and a phase of tectonic uplift at the Lindi Fracture Zone. Along the entire coast of Tanzania terraces were periodically elevated due to extensional episodes in the eastern branch of the East African Rift System during the Quaternary. However, the exact timing of these tectonic pulses was so far impossible. Our results show that the emergence of the Lindi coast was linked to a period of tectonic activity in the East African Rift System after ~50 ka. The decline of the marl prairie was initiated at ~33 ka BP due to the onset of the Last Glacial Aridity Maximum in equatorial East Africa.

Reuter, M.; Piller, W. E.; Harzhauser, M.; Kroh, A.; Berning, B.

2009-04-01

354

Mosquito-borne arbovirus surveillance at selected sites in diverse ecological zones of Kenya; 2007 -- 2012.  

PubMed

BACKGROUND: Increased frequency of arbovirus outbreaks in East Africa necessitated the determination of distribution of risk by entomologic arbovirus surveillance. A systematic vector surveillance programme spanning 5 years and covering 11 sites representing seven of the eight provinces in Kenya and located in diverse ecological zones was carried out. METHODS: Mosquitoes were sampled bi-annually during the wet seasons and screened for arboviruses. Mosquitoes were identified to species, pooled by species, collection date and site and screened for arboviruses by isolation in cell culture and/or RT-PCR screening and sequencing. RESULTS: Over 450,000 mosquitoes in 15,890 pools were screened with 83 viruses being detected/isolated that include members of the alphavirus, flavivirus and orthobunyavirus genera many of which are known to be of significant public health importance in the East African region. These include West Nile, Ndumu, Sindbis, Bunyamwera, Pongola and Usutu viruses detected from diverse sites. Ngari virus, which was associated with hemorrhagic fever in northern Kenya in 1997/98 was isolated from a pool of Anopheles funestus sampled from Tana-delta and from Aedes mcintoshi from Garissa. Insect only flaviviruses previously undescribed in Kenya were also isolated in the coastal site of Rabai. A flavivirus most closely related to the Chaoyang virus, a new virus recently identified in China and two isolates closely related to Quang Binh virus previously unreported in Kenya were also detected. CONCLUSION: Active transmission of arboviruses of public health significance continues in various parts of the country with possible undetermined human impact. Arbovirus activity was highest in the pastoralist dominated semi-arid to arid zones sites of the country where 49% of the viruses were isolated suggesting a role of animals as amplifiers and indicating the need for improved arbovirus disease diagnosis among pastoral communities. PMID:23663381

Ochieng, Caroline; Lutomiah, Joel; Makio, Albina; Koka, Hellen; Chepkorir, Edith; Yalwala, Santos; Mutisya, James; Musila, Lillian; Khamadi, Samoel; Richardson, Jason; Bast, Joshua; Schnabel, David; Wurapa, Eyako; Sang, Rosemary

2013-05-10

355

Child Labor and School Attendance in Kenya  

ERIC Educational Resources Information Center

Sub-Saharan Africa has the highest incidence of child labor in the world and estimates show that it continues to grow. This paper examines the causes and magnitude of child labor in Kenya. Unlike previous studies that examined child labor as only an economic activity, this paper includes household chores. Including household chores is important…

Moyi, Peter

2011-01-01

356

Relationship Transitions among Youth in Urban Kenya  

ERIC Educational Resources Information Center

The process of courtship and marriage in sub-Saharan Africa has changed remarkably. These changes, however, have received scant attention because recent research has focused on adolescent relationships' links to HIV/AIDS rather than to marriage. Drawing on detailed reports of 1,365 romantic and sexual partnerships from youths in Kisumu, Kenya, we…

Clark, Shelley; Kabiru, Caroline; Mathur, Rohini

2010-01-01

357

18O 16O ratios in cherts associated with the saline lake deposits of East Africa  

USGS Publications Warehouse

The cherts formed from sodium silicate precursors in East African saline, alkaline lakes have ??18O values ranging from 31.1 to 44.1. The ??18O values correlate in general with lake salinities as inferred from geologic evidence, indicating that most chert was formed from its precursor in contact with lake water trapped at the time of deposition. A few of the analyzed cherts probably formed in contact with dilute meteoric water. From the widely varying ??18O values we conclude that precursors were transformed to chert in fluids of widely varying salinity and aNa+/aH+ ratio. ?? 1973.

O'Neil, J. R.; Hay, R. L.

1973-01-01

358

Chinese propriety medicines: an "alternative modernity?" The case of the anti-malarial substance artemisinin in East Africa.  

PubMed

This article discusses various modes of "modernizing" traditional Chinese medical drugs (zhongyao [image: see text]) and transforming them into so-called Chinese propriety medicines (zhongchengyao [image: see text]) that are flooding the current neoliberal wellness markets. This article argues that the chemical procedures used in the manufacture of Chinese propriety medicines are highly culture-specific and deserve being considered as instantiations of an "alternative modernity" (e.g., Knauft 2002), rather than of "Westernization." These Western-Chinese combinations, produced in strife toward fulfilling Mao Zedong's Communist-revolutionary vision, have a potential to represent a critical alterity to Western health policies, challenging rhetoric against such combinations. However, as is also noted in this article based on ethnographic fieldwork in East Africa, their potential alterity has been corroded for at least two reasons. First, the medical rationale for dispensing these medications has been shaped by commercial demands in ways that have worked toward transforming the formerly scholarly Chinese medical tradition (as outlined by Bates 1995) into a consumer-near and popular "folk medicine" (as defined by Farquhar 1994:212). Second, the repertoire of Chinese propriety medicines is impoverished as its efficacious "alternatively modern" drugs are being redefined as "modern" biomedical drugs. The article concludes that the potentially critical alterity of any formerly scholarly traditional medicine is more likely to be lost in those fields of health care that are both highly commercialized and polarized by the biomedical imperative to distinguish between "traditional" and "modern" medicines. As example for demonstrating how contentious the issue is, qinghaosu [image: see text] (artemisinin) is put center stage. It is an anti-malarial substance which in the 1970s Chinese scientists extracted from the Chinese medical drug qinghao [image: see text] (Herba Artemisiae annuae). Some Chinese practitioners in East Africa argued that artemisinin belonged among the Chinese propriety medicines they sold. Although according to Western biomedical criteria and the Chinese scientists who were involved in its chemical identification, artemisinin is a "modern" Western drug, their polemics deserve to be more closely analyzed as what social scientists have recognized as an "alternative modernity." PMID:19404880

Hsu, Elisabeth

2009-01-01

359

High-Resolution Geochemical and Paleoecological Records of Climate Change Since the Late Glacial at Lake Tanganyika, East Africa  

NASA Astrophysics Data System (ADS)

We used high-resolution geochemical and paleoecological records from shallow-water sediment cores to refine previous descriptions of climatic conditions at Lake Tanganyika, East Africa, for the period from the Late Glacial to the present. Radiocarbon and 210Pb dating were used to establish chronologies for the cores. Sedimentological changes indicate that lake level has risen approximately 50-70 m since the Late Glacial. A depositional hiatus occurred between 6.4 and 11.4 ka BP (all dates in calendar years) in several of the shallow-water cores. Elemental abundance (%C, %N) and stable isotopic (?15N, ?13C) data for one core suggest that substantial changes in primary productivity and nutrient recycling regimes have occurred since 6.4 ka BP. Carbonate and ostracode crustacean preservation were low and nil, respectively, prior to 2.4 ka BP. Generally, these data support previous interpretations of regional paleoclimate and lake conditions, with wet and warm conditions during the interval from 6.4 to 4.0 ka, and increasingly arid conditions since 2.4 ka. However, for the interval from 4.0 to 2.4 ka, paleoenvironmental indicators (?15N, reduced carbonate and ostracode preservation) suggest that the central part of Lake Tanganyika was stably stratified at a shallower depth than present as a result of diminished southerly trade winds. After 2.4 ka BP, sedimentary carbonate concentrations increase, and ?13C values become enriched, suggesting that lacustrine productivity increased with the resumption of deeper wind-driven mixing, lasting until 1 ka BP. For post-2.4 ka samples, species abundance data for ostracodes were used to generate an ostracode water depth index (OWDI). OWDI indicated that severe drought conditions were persistent or recurred at Lake Tanganyika between 1550 and 1850 A.D. Droughts resulted in marked lowstands at Lake Tanganyika at 1580+/-15 A.D., 1730+/-35 A.D., and 1800+/-30 A.D. These data contribute new information on the timing of Little Ice Age droughts and Mid-Late Holocene changes in trade wind intensity in tropical East Africa.

Alin, S. R.; Cohen, A. S.

2002-12-01

360

Molecular records of climate variability and vegetation response since the Late Pleistocene in the Lake Victoria basin, East Africa  

NASA Astrophysics Data System (ADS)

New molecular proxies of temperature and hydrology are helping to constrain tropical climate change and elucidate possible forcing mechanisms during the Holocene. Here, we examine a ˜14,000 year record of climate variability from Lake Victoria, East Africa, the world's second largest freshwater lake by surface area. We determined variations in local hydroclimate using compound specific ?D of terrestrial leaf waxes, and compared these results to a new record of temperature utilizing the TEX86 paleotemperature proxy, based on aquatic Thaumarchaeotal membrane lipids. In order to assess the impact of changing climate on the terrestrial environment, we generated a record of compound specific ?13C from terrestrial leaf waxes, a proxy for ecosystem-level C3/C4 plant abundances, and compared the results to previously published pollen-inferred regional vegetation shifts. We observe a general coherence between temperature and rainfall, with a warm, wet interval peaking ˜10-9 ka and subsequent gradual cooling and drying over the remainder of the Holocene. These results, particularly those of rainfall, are in general agreement with other tropical African climate records, indicating a somewhat consistent view of climate over a wide region of tropical East Africa. The ?13C record from Lake Victoria leaf waxes does not appear to reflect changes in regional climate or vegetation. However, palynological analyses document an abrupt shift from a Poaceae (grasses)-dominated ecosystem during the cooler, arid late Pleistocene to a Moraceae-dominated (trees/shrubs) landscape during the warm, wet early Holocene. We theorize that these proxies are reflecting vegetation in different locations around Lake Victoria. Our results suggest a predominantly insolation-forced climate, with warm, wet conditions peaking at the maximum interhemispheric seasonal insolation contrast, likely intensifying monsoonal precipitation, while maximum aridity coincides with the rainy season insolation and the interhemispheric contrast gradient minima. We interpret a shift in conditions at the Younger Dryas to indicate a limited switch in insolation-dominated control on climate of the Lake Victoria region, to remote teleconnections with the coupled Atlantic and Pacific climate system.

Berke, Melissa A.; Johnson, Thomas C.; Werne, Josef P.; Grice, Kliti; Schouten, Stefan; Sinninghe Damsté, Jaap S.

2012-11-01

361

Ground Truth, Magnitude Calibration and Regional Phase Propagation and Detection in the Middle East and Horn of Africa  

SciTech Connect

In this project, we are exploiting several seismic data sets to improve U.S. operational capabilities to monitor for low yield nuclear tests across the Middle East (including the Iranian Plateau, Zagros Mountains, Arabian Peninsula, Turkish Plateau, Gulf of Aqaba, Dead Sea Rift) and the Horn of Africa (including the northern part of the East African Rift, Afar Depression, southern Red Sea and Gulf of Aden). The data sets are being used to perform three related tasks. (1) We are determining moment tensors, moment magnitudes and source depths for regional events in the magnitude 3.0 to 6.0 range. (2) These events are being used to characterize high-frequency (0.5-16 Hz) regional phase attenuation and detection thresholds, especially from events in Iran recorded at stations across the Arabian Peninsula. (3) We are collecting location ground truth at GT5 (local) and GT20 (regional) levels for seismic events with M > 2.5, including source geometry information and source depths. Towards meeting these objectives, seismograms from earthquakes in the Zagros Mountains recorded at regional distances have been inverted for moment tensors, which have then been used to create synthetic seismograms to determine the source depths of the earthquakes via waveform matching. The source depths have been confirmed by modeling teleseismic depth phases recorded on GSN and IMS stations. Early studies of the distribution of seismicity in the Zagros region found evidence for earthquakes in the upper mantle. But subsequent relocations of teleseismic earthquakes suggest that source depths are generally much shallower, lying mainly within the upper crust. All of the regional events studied so far nucleated within the upper crust, and most of the events have thrust mechanisms. The source mechanisms for these events are being used to characterize high-frequency (0.5-16 Hz) regional phase attenuation and detection thresholds for broadband seismic stations in the Arabian Peninsula, including IMS stations and stations belonging to the Saudi Arabian National Digital Seismic Network. To improve event locations, source mechanisms and attenuation estimates, new regional P and S wave velocity models of the upper mantle under the Arabian Peninsula have also been developed using data from teleseismic events recorded at stations within the Arabian Peninsula and Horn of Africa. These models show slower-than-average velocities within the lithospheric mantle under the entire Arabian Shield. However, at sublithospheric mantle depths, the low velocity region appears to be localized beneath the western side of the Arabian Shield.

Nyblade, A; Brazier, R; Adams, A; Park, Y; Rodgers, A; Al-Amri, A

2007-07-08

362

Climate Variability and the Outbreaks of Cholera in Zanzibar, East Africa: A Time Series Analysis  

PubMed Central

Global cholera incidence is increasing, particularly in sub-Saharan Africa. We examined the impact of climate and ocean environmental variability on cholera outbreaks, and developed a forecasting model for outbreaks in Zanzibar. Routine cholera surveillance reports between 1997 and 2006 were correlated with remotely and locally sensed environmental data. A seasonal autoregressive integrated moving average (SARIMA) model determined the impact of climate and environmental variability on cholera. The SARIMA model shows temporal clustering of cholera. A 1°C increase in temperature at 4 months lag resulted in a 2-fold increase of cholera cases, and an increase of 200 mm of rainfall at 2 months lag resulted in a 1.6-fold increase of cholera cases. Temperature and rainfall interaction yielded a significantly positive association (P < 0.04) with cholera at a 1-month lag. These results may be applied to forecast cholera outbreaks, and guide public health resources in controlling cholera in Zanzibar.

Reyburn, Rita; Kim, Deok Ryun; Emch, Michael; Khatib, Ahmed; von Seidlein, Lorenz; Ali, Mohammad

2011-01-01

363

Socio-economic environment of technology underdevelopment in the Third World: the case of East Africa  

SciTech Connect

The literature review first reveals a wide range of views regarding what is meant by technology, what approaches lead to technological development, and what accounts for the technological lag of the LTCs. Differences also emerge regarding proper technologies and the proper techno-economic roles of countries. This study represents an attempt to identify the conditions that give rise to technology underdevelopment and to examine the implication of such technological underdevelopment to social and economic prospects in a representative corner of the underdeveloped world, the East African region. The research is guided by the question, What are the major causes of technology underdevelopment in the East African Countries. State more specifically, the question becomes, What relationships exist between (1) a society's structure of economic production and its technological development. and (2) the patterns and compositions of international trade, on the one hand, and technology (under)development, on the other. The research utilizes as its analytical points of departure the theories of Comparative Advantage, Factor Endowments, and the political economy theory of Dependency, with the aim of both surfacing the underlying assumptions and critically analyzing the models that have shaped the current state of the LTCs' technologies.

Felleke, G.

1986-01-01

364

Sedimentary provinces of Africa, Middle East, and South America, classification and hydrocarbon potential  

SciTech Connect

In all, 243 sedimentary provinces (basins, foldbelts) were analyzed, classified, and graphically displayed on continental maps (1:5,000,000). An elaborate system of symbols and colors shows the plate tectonic history of each province, the stratigraphic extent and thickness of the sedimentary fill, the type of basin-forming and basin-modifying tectonics, and the distribution of oil and gas fields. The provinces are grouped into five classes which correspond to principal plate tectonic settings: (1) intracontinental basins (rifts, sags), (2) divergent margins, (3) convergent margins, (4) oceanic basins, and (5) orogenic belts and associated basins (e.g., foreland and intermontane basins). The history of each province is determined by critical stages of the plate tectonic cycle: (1) rifting, (2) drifting and sagging, (3) subduction and continental collision. Simple basins form during a single stage of a plate tectonic cycle, e.g., the Tertiary Red Sea rift. Polyhistory provinces have several stages of a primary cycle (e.g., the divergent continental margins of west Africa overlap the intracontinental rift stage). In more complexes provinces the history may extend over two cycles (e.g., northwest Africa with elements of the Paleozoic cycle ending at the Hercynian orogeny overlain by the Mesozoic and Cenozoic cycle which ends with the Alpine orogeny). The provinces affected and/or associated with continental collision such as the folded and faulted forelands and foreland basins contain more than 80% of all proven reserves of hydrocarbons. The maps reveal many aspects of the Phanerozoic history on a continental scale relevant to exploration for hydrocarbons.

Picha, F.J.

1988-02-01

365

Analysis of the summertime buildup of tropospheric ozone abundances over the Middle East and North Africa as observed by the Tropospheric Emission Spectrometer instrument  

NASA Astrophysics Data System (ADS)

We use the GEOS-Chem chemical transport model to interpret observations of tropospheric ozone from the Tropospheric Emission Spectrometer (TES) satellite instrument in summer 2005. Observations from TES reveal elevated ozone in the middle troposphere (500-400 hPa) across North Africa and the Middle East. Observed ozone abundances in the middle troposphere are at a maximum in summer and a minimum in winter, consistent with the previously predicted summertime "Middle East ozone maximum." This summertime enhancement in ozone is associated with the Arabian and Sahara anticyclones, centered over the Zagros and Atlas Mountains, respectively. These anticyclones isolate the middle troposphere over northeast Africa and the Middle East, with westerlies to the north and easterlies to the south, facilitating the buildup of ozone. Over the Middle East, we find that in situ production and transport from Asia provides comparable contributions of 30-35% to the ozone buildup. Over North Africa, in situ production is dominant (at about 20%), with transport from Asia, North America, and equatorial Africa each contributing about 10-15% to the total ozone. We find that although the eastern Mediterranean is characterized by strong descent in the middle and upper troposphere in summer, transport from the boundary layer accounts for about 25% of the local Middle Eastern contribution to the ozone enhancement in the middle troposphere. This upward transport of boundary layer air is associated with orographic lifting along the Zagros Mountains in Iran and the Asir and Hijaz Mountain ranges in Saudi Arabia, and is consistent with TES observations of deuterated water.

Liu, Jane J.; Jones, Dylan B. A.; Worden, John R.; Noone, David; Parrington, Mark; Kar, Jay

2009-03-01

366

Lake-level history of Lake Tanganyika, East Africa, for the past 2500 years based on ostracode-inferred water-depth reconstruction  

Microsoft Academic Search

Assemblages of ostracodes from sediment cores illuminate lake-level history at decadal to centennial timescales during the late Holocene at Lake Tanganyika, East Africa. The ostracode-based lake-level curves for several cores resemble both each other and the only previously published lake-level record of comparable resolution for Lake Tanganyika during this interval, successfully reconstructing known highstands, improving the chronology of known lowstands,

Simone R. Alin; Andrew S. Cohen

2003-01-01

367

An annoted list of the parasites of graminaceous stem borers in East Africa, with a discussion of their potential in biological control  

Microsoft Academic Search

This paper is based on a survey of the parasites of the lepidopterous stem borers of graminaceous crops throughout East Africa\\u000a and on laboratory studies of the more abundant species. In the survey emphasis was placed on the borers of maize and sorghum,\\u000a but samples of other cultivated Graminae and wild grasses were also taken.\\u000a \\u000a Notes on the distribution and

A. I. Mohyuddin; D. J. Greathead

1970-01-01

368

Spatio-temporal patterns of genetic change amongst populations of cassava Bemisia tabaci whiteflies driving virus pandemics in East and Central Africa.  

PubMed

The greatest current threat to cassava in sub-Saharan Africa, is the continued expansion of plant virus pandemics being driven by super-abundant populations of the whitefly vector, Bemisia tabaci. To track the association of putatively genetically distinct populations of B. tabaci with pandemics of cassava mosaic disease (CMD) and cassava brown streak disease (CBSD), a comprehensive region-wide analysis examined the phylogenetic relationships and population genetics of 642 B. tabaci adults sampled from cassava in six countries of East and Central Africa, between 1997 and 2010, using a mitochondrial DNA cytochrome oxidase I marker (780 bases). Eight phylogenetically distinct groups were identified, including one, designated herein as 'East Africa 1' (EA1), not previously described. The three most frequently occurring groups comprised >95% of all samples. Among these, the Sub-Saharan Africa 2 (SSA2) group diverged by c. 8% from two SSA1 sub-groups (SSA1-SG1 and SSA1-SG2), which themselves were 1.9% divergent. During the 14-year study period, the group associated with the CMD pandemic expansion shifted from SSA2 to SSA1-SG1. Population genetics analyses of SSA1, using Tajima's D, Fu's Fs and Rojas' R2 statistics confirmed a temporal transition in SSA1 populations from neutrally evolving at the outset, to rapidly expanding from 2000 to 2003, then back to populations more at equilibrium after 2004. Based on available evidence, hybrid introgression appears to be the most parsimonious explanation for the switch from SSA2 to SSA1-SG1 in whitefly populations driving cassava virus pandemics in East and Central Africa. PMID:24291251

Legg, James P; Sseruwagi, Peter; Boniface, Simon; Okao-Okuja, Geoffrey; Shirima, Rudolph; Bigirimana, Simon; Gashaka, Gervais; Herrmann, Hans-Werner; Jeremiah, Simon; Obiero, Hannington; Ndyetabula, Innocent; Tata-Hangy, Willy; Masembe, Charles; Brown, Judith K

2014-06-24

369

Focal mechanisms and the stress regime in NE and SW Tanzania, East Africa  

NASA Astrophysics Data System (ADS)

We report 12 new focal mechanisms from earthquakes in NE and SW Tanzania where the stress regime within the East African rift system is not well constrained. Focal mechanisms for events at the intersection of the Lake Tanganyika and Rukwa rifts in SW Tanzania indicate a complicated stress pattern with possible dextral strike-slip motion on some faults but oblique motion on others (either sinistral on NW striking faults or dextral on NE striking faults). Within the Rukwa rift, focal mechanisms indicate normal dip-slip motion with NE-SW opening. In NE Tanzania where the Eastern rift impinges on the margin of the Tanzania Craton, fault motions are consistent with a zone of distributed block faults and sub E-W extension. All twelve earthquakes likely nucleated within the crust.

Brazier, Richard A.; Nyblade, Andrew A.; Florentin, Juliette

2005-07-01

370

Development of coarse-grained facies in lacustrine rift basins: Examples from East Africa  

NASA Astrophysics Data System (ADS)

Detailed studies of high-resolution and multifold seismic reflection data from the two largest East African rift lakes, Malawi and Tanganyika, reveal a complex suite of coarse-grained depositional facies. These facies occur within specific regions of the controlling half grabens that compose the rift lakes. Sand-prone environments include subaqueous channels and small drowned fluvial complexes. Channel systems range from large erosional canyons to deep-water turbidite channel-levee systems. Lowstand and highstand deltas of axial and shoaling-side rivers are volumetrically important coarse-grained facies. Fan deltas develop along the base of major border faults during lake lowstands; subaqueous talus fan deposits occur along the base of the border faults during lake highstands. Lowstand deltas are the best-preserved progradational facies in these rift lakes. In addition to simple tectonic control, drastic tectonically or climatically induced lake-level change significantly regulates the production of coarse-grained lacustrine synrift deposits.

Scholz, Christopher A.; Rosendahl, Bruce R.; Scott, Deborah L.

1990-02-01

371

Safety of tumor necrosis factor inhibitors use for rheumatoid arthritis and ankylosing spondylitis in Africa, the Middle East, and Asia: focus on severe infections and tuberculosis.  

PubMed

Multiple studies of patients in Western countries with rheumatoid arthritis (RA) and ankylosing spondylitis (AS) have indicated increased risk for active tuberculosis (TB) and other infections among these individuals. It has also been consistently reported that patients receiving tumor necrosis factor (TNF) inhibitors for these conditions have higher rates of active TB and other infections than RA or AS patients not receiving these medications. These issues have been studied less extensively in the Asia and Africa-Middle East regions, and information from these regions is important because of higher rates of TB in the general population. This paper reviews studies of RA and AS patients from Asia, Africa, and the Middle East who received TNF inhibitors. A literature search was conducted using http://www.ncbi.nlm.nih.gov/pubmed to collect and report these data. The years included in the PubMed literature search ranged from January 2000 to October 2011. Additionally, information from the China Hospital Knowledge Database was used to report data from Chinese patients with RA and AS treated with TNF inhibitors. Results from these studies indicate that the risk for active TB and other infections in AS and RA patients from Asia, Africa, and the Middle East are increased in patients receiving TNF inhibitors and that the risk is higher among those treated with monoclonal antibodies versus soluble TNF receptor. PMID:23242389

Hammoudeh, Mohammed; Alarfaj, Abdurhman; Chen, Der-Yuan; Djoudi, Hachemi; Youseif, Ehab; Zhu, Jian

2013-03-01

372

Environmental Magnetism as an Instrument for Characterizing Paleoclimatic Variations in the Sediment Record of Lake Tanganyika, East Africa.  

NASA Astrophysics Data System (ADS)

Due to their age and their continuous record of sedimentation, the lacustrine sediments of Lake Tanganyika, East Africa, provide an excellent resource for paleoclimatic research. During an eight-day cruise in July of 2004, participants in the Nyanza Project collected four Kullenburg piston cores in the vicinity of the Kalya horst, a mid-lake topographic high located south of the Mahale Mountains. Thirty meters of core were recovered. Initial lithologic analysis of the cores revealed that they consist of massive silty clay beds alternating with laminated diatomaceous oozes. U-channel samples were collected from the cores in order to obtain a continuous record of paleomagnetic directions recorded by the sediments as well as an environmental record of changes in the composition and concentration of magnetic minerals. In conjunction with other techniques, the directional record will help to provide a chronology for the cores, which are thought to extend well into Marine Isotope Stage 3. This chronology will be used to place the evolution of the lake system and its sedimentary processes within the context of global climate variability. The environmental magnetic record will provide information about both large-scale and small-scale climatic variations. The paleomagnetic and environmental magnetic information obtained from these cores will make it possible to draw definitive conclusions about past climate variations, current atmospheric composition, and the present-day quality of the lake.

Wetter, L.; Verosub, K.; Acton, G.; Russell, J.

2004-12-01

373

Evaluation of a regional mineral dust model over Northern Africa, Southern Europe and Middle East with AERONET data  

NASA Astrophysics Data System (ADS)

A variety of regional and global models of the dust aerosol cycle have been developed since early 1990s. Dust models are essential to complement dust-related observations, understand the dust processes and predict the impact of dust on surface level PM concentrations. Dust generation and the parameterization of its deposition processes shows a high variability on spatial and temporal scales. It responds, in a non-linear way, to a variety of environmental factors, such as soil moisture content, the type of surface cover or surface atmospheric turbulence. Thus the modelling of this very complex process is a challenge. DREAM (Dust Regional Atmospheric Model; Nickovic et al., 2001) provides operational dust forecasts for Northern Africa, Europe and Middle East, as well as for the East-Asia regions. DREAM is operated and further developed in the Barcelona Supercomputing Center. DREAM is fully inserted as one of the governing equations in the NCEP/Eta atmospheric model and simulates all major processes of the atmospheric dust cycle. In order to implement new model versions for operational applications there is a need for extensive checking and validation against real observations. The present study focuses on the evaluation of forecasting capacity of the new version of DREAM by means of a model-to-observation comparison of the Aerosol Optical Depth (AOD) over Northern Africa, Southern Europe and Middle East for one year. The model provides 72h forecasts initialized at 12UTC of each day with outputs every 1 hour at horizontal resolution of about 1/3° and 24 z-vertical layers in the troposphere. Comparisons against 47 selected AERONET sites are used. Eight size bins between 0.1 and 10 µm are considered, and dust-radiation interactions are included (Pérez et al., 2006). Wet deposition scheme has been also improved. The simulation has been performed over one year (2004); statistics and time series for the model outputs and AERONET data are used to evaluate the ability of the model to reproduce AOD (at 550nm) associated to mineral dust 24, 48 and 72h ahead. A suit of discrete statistics as Mean Normalized Bias Error (MNBE), Mean Normalized Gross Error (MNGE) and Root Mean Square Error (RMSE) has been used in order to evaluate the model behaviour. Categorical statistics or skill scores, as model accuracy, bias, probability of detection, false alarm rate and critical success index have been implemented to test the capability of the model to simulate AOD exceeding thresholds defined by the quartiles of each AERONET site. A previous aerosol characterization of AERONET data has been performed for our study region in order to discriminate desert dust contributions (Basart et al., 2008). The first results of the comparison reveal that the modelled dust field agrees in general reasonably well with sun photometer data. Since dust long-range transport is mainly driven by smaller dust particles, the results of this new 8-bins version (with increased number of dust size bins) is considerably better, since the small particle size range (<10µm effective radius) is well described. The best scores are found in North Africa and Middle East. In the Sahel region, an important sub-estimation is observed in wintertime, when the Atlantic outflow transport is important. This is partially due to the more complex processes associated to dust generation in this region (Warren et al., 2007), not well parameterized in dust models yet. Other causes, such as the correct simulation of regional winds or the threshold friction velocity are under research. Moreover, the interaction of mineral dust and biomass burning aerosols from Savannah fires is at its maximum over the region in this season. In southern Europe, the relative errors are higher than in the rest of our study domain mainly due to the presence of different types of aerosols (such as fine pollution aerosols) which appear well-mixed with desert dust. References: Basart, S., C. Pérez, E. Cuevas and J.M. Baldasano. 2008. "Aerosol retrospective analysis over North Africa, North-eastern Atlant

Basart, S.; Pérez, C.; Cuevas, E.; Baldasano, J. M.

2009-04-01

374

The ability of cultivars of sweetpotato in East Africa to 'revert' from Sweet potato feathery mottle virus infection.  

PubMed

Asymptomatic field plants are the normal source of the vine cuttings used as sweetpotato planting material in Africa. Previous and new tests of such East African material, mostly using the very sensitive method of graft inoculation to the indicator plant Ipomoea setosa, showed that a majority tested virus-negative. This was despite their never having undergone any science-based therapy. To investigate how this occurs, in a replicated greenhouse experiment, plants of susceptible cultivars from the USA and Peru and three resistant Ugandan cultivars were graft-inoculated with Sweet potato feathery mottle virus (SPFMV), the commonest virus infecting sweetpotato. When the grafts were established, cuttings were taken, rooted and proved to be infected. The health status of each of these new plants was then followed over a 10-week period using a quantitative polymerase chain reaction assay. Most of the plants of the Ugandan cultivars eventually tested SPFMV-negative whereas those of the USA and Peru seldom did. Furthermore, in subsequent graft-inoculations of scions from the tip, top, middle and base of the vine of every plant to I. setosa plants, again, most of the scions of the Ugandan cultivars tested SPFMV-negative whereas those of the USA and Peru seldom did. These tests demonstrate the phenomenon of reversion in the Ugandan cultivars and can explain how most unprotected Ugandan sweetpotato field plants tested SPFMV-negative. PMID:24361352

Gibson, Richard W; Wasswa, Peter; Tufan, Hale A

2014-06-24

375

Worldwide geophysical activity expanding: First half increase focused in Far East, Africa; now shooting in `Fourth Dimension,` streamer count up  

SciTech Connect

Worldwide seismic vessel activity continued to expand in the first six months of 1995. The vessel count grew from 81 to 84 vessels - a 4% increase. Along with this expansion was a significant shift of activity to the western Pacific, focused in the Far East and Africa. A 56% increase in vessel count is due to strong exploration activity in Southeast Asia. Another era is opening in the oil and gas industry. Four-dimensional (4-D) seismic technology is available to assist in the development of offshore oil and gas reserves only two years after 3-D seismic became the preferred exploration technology. In its simple form, 4-D seismic is the collection of 3-D seismic datasets at regular intervals throughout the life of an oilfield. Costs are minimized because the seismic vessel does not tow long streamers, only the airgun sources. The fixed sensor grid collects spatially identical information that can be compared to earlier surveys. Annual 3-D seismic snapshots permit petroleum companies to track changes in reservoir fluid levels. It also allows the discrete computer modeling of a field and the validation of that model`s predictive value. The benefits of using 4-D seismic result in more efficient operations, better asset allocation, debt planning, and profit projections.

Schmidt, V.A.

1995-08-01

376

An isotopic study of a fluvial-lacustrine sequence: The Plio-Pleistocene koobi fora sequence, East Africa  

USGS Publications Warehouse

Stable isotopic analyses of Plio-Pleistocene and modern sediments in the fluvial-lacustrine system occupying the Turkana Basin, East Africa provide constraints on the paleoenvironmental and diagenetic histories of the Pliocene through the Recent sediments in the basin. The ??13C values for carbonates in lacustrine sediments range from -15 to +22??? relative to PDB, depending on the varying proportions of CO2 from the atmospheric reservoir and from various metabolic sources. The ??18O values of carbonates in lacustrine sediments indicate that the isotopic composition of paleolake water varied by over 10??? from the Pliocene to the present. The ??13C values for pedogenic carbonates record paleoccologic variations and suggest that C4 plants did not become well established in the preserved depositional parts of the basin until about 1.8 myr ago. The ??18O values pedogenic carbonates suggest a range of over 10??? for the isotopic composition of soil water during this interval. They also suggest a period of major climatic instability from about 3.4 to 3.1 myr and at about 1.8 myr. Together, the ??13C and ??18O values of pedogenic carbonates indicate that the present conditions are as arid and hot as any that had prevailed during deposition of these Plio-Pleistocene sediments. ?? 1988.

Cerling, T. E.; Bowman, J. R.; O'Neil, J. R.

1988-01-01

377

Characterizing the Effects of Irrigation in the Middle East and North Africa Using Remotely Sensed Vegetation and Water Cycle Observations  

NASA Technical Reports Server (NTRS)

A majority of the countries in the Middle East and North Africa (MENA) region suffer from water scarcity due in part to widespread rainfall deficits, unprecedented levels of water demand, and the inefficient use of renewable freshwater resources. Since a majority of the water withdrawal in the MENA is used for irrigation, there is a desperate need for improved understanding of irrigation practices and agricultural water use in the region. Here, satellite-derived irrigation maps and crop-type agricultural data are applied to the Land Data Assimilation System for the MENA region (MENA LDAS), designed to provide regional, gridded fields of hydrological states and fluxes relevant for water resources assessments. Within MENA-LDAS, the Catchment Land Surface Model (CLSM) simulates the location, timing, and amount of water applied through agricultural irrigation practices over the region from 2002-2012. In addition to simulating the irrigation impact on evapotranspiration, soil moisture, and runoff, we also investigate regional changes in terrestrial water storage (TWS) observed from the Gravity Recovery and Climate Experiment (GRACE) and simulated by CLSM.

Bolten, John; Ozdogan, Mutlu; Beaudoing, Hiroko; Rodell, Matthew

2012-01-01

378

A human economy: A "third way" for the future of young people in the Middle East and North Africa  

NASA Astrophysics Data System (ADS)

This paper looks at the vulnerability of today's youth worldwide, with a particular focus on the Middle East and North Africa (MENA), where the proportion of citizens aged 12-24 is particularly high at one-third of the total population. Cursed with poor education and few work opportunities, the youth unemployment rate has risen to 50 per cent in this region. There is a consequent lack of participation at all levels, and a large number of youth are showing symptoms of low self-esteem, frustration, anger and unrest. After discussing the outcomes of years of an inhuman economic system on a global level, this article points to a more humane and empowering path. The author argues that, instead of continuing with profit-oriented capitalism or relying on the informal sector, the co-operative way represents a third alternative to existing economic sectors within the dominant contemporary economic system. The article analyses the many benefits of this path for the realisation of a humane economy. In so doing, it touches on issues of equity and social protection. Finally, the article outlines what needs to be done if this is to be a viable solution for a human economy. While giving many examples of successful co-operative enterprises worldwide, the author singles out the MENA region as one which could also benefit from the new trends outlined.

Zaalouk, Malak

2013-09-01

379

Chromosomal diagnostic criteria for some members of Simulium damnosum complex in east Africa.  

PubMed

Identification of Simulium damnosum s.l. vectors of onchocerciasis demands adequate knowledge of the chromosomal features that distinguish human-biting members from nonanthropophilic forms. In this study, 955 S. damnosum larvae collected from various geographical locations in Tanzania were chromosomally analyzed. 358 larvae from small mountain streams in the northeast and central regions of Tanzania, were identified as mainly Nyamagasani and Sanje forms, with only one Kiwira form. 378 larvae from plain and lowland rivers, also in the northeast and central regions, were identified as Nkusi, Kisiwani and Kibwezi forms. Chromosomal examination of 219 larvae from the southern highlands zone revealed the presence of Kiwira and Nyamagasani forms. A further 27 larvae of S. damnosum complex collected from 5 rivers in Uganda were identified as Sebwe and Nkusi forms. Chromosomal photomicrographs on which the distinguishing characters were based are provided. These observations are discussed in the light of previous studies carried out on the S. damnosum cytological forms in Eastern Africa. PMID:8256090

Maegga, B T; Cupp, E W

1993-09-01

380

Validity of the Patient Health Questionnaire-9 for depression screening and diagnosis in East Africa.  

PubMed

Depression is often underdiagnosed and undertreated in primary care settings, particularly in developing countries. This is, in part, due to challenges resulting from lack of skilled mental health workers, stigma associated with mental illness, and lack of cross-culturally validated screening instruments. We conducted this study to evaluate the reliability and validity of the Patient Health Questionnaire-9 (PHQ-9) as a screen for diagnosing major depressive disorder among adults in Ethiopia, the second most populous country in sub-Saharan Africa. A total of 926 adults attending outpatient departments in a major referral hospital in Ethiopia participated in this study. We assessed criterion validity and performance characteristics against an independent, blinded, and psychiatrist administered semi-structured Schedules for Clinical Assessment in Neuropsychiatry (SCAN) interview. Overall, the PHQ-9 items showed good internal (Cronbach's alpha=0.81) and test re-test reliability (intraclass correlation coefficient=0.92). A factor analysis confirmed a one-factor structure. Receiver Operating Characteristics (ROC) analysis showed that a PHQ-9 threshold score of 10 offered optimal discriminatory power with respect to diagnosis of major depressive disorder via the clinical interview (sensitivity=86% and specificity=67%). The PHQ-9 appears to be a reliable and valid instrument that may be used to diagnose major depressive disorders among Ethiopian adults. PMID:23972787

Gelaye, Bizu; Williams, Michelle A; Lemma, Seblewengel; Deyessa, Negussie; Bahretibeb, Yonas; Shibre, Teshome; Wondimagegn, Dawit; Lemenhe, Asnake; Fann, Jesse R; Vander Stoep, Ann; Andrew Zhou, Xiao-Hua

2013-12-15

381

Rainfall intensity and groundwater recharge: evidence from ground-based observations in East Africa (Invited)  

NASA Astrophysics Data System (ADS)

Global greenhouse-gas emissions serve to warm Africa more rapidly than the rest of the world. The intensification of precipitation that is associated with this warming, strongly influences terrestrial water budgets. This shift toward fewer but heavier rainfall events is expected to lead to more frequent and intense floods as well as more variable and lower soil moisture. However, its impact on groundwater recharge is unclear and in dispute. We review evidence from long (1 to 5 decades) time series of groundwater levels recorded in deeply weathered crystalline rock aquifers systems underlying land surfaces of low relief in Uganda and Tanzania. Borehole hydrographs consistently demonstrate a non-linear relationship between rainfall and recharge wherein heavy rainfalls exceeding a threshold contribute disproportionately to the recharge flux. Rapid responses observed in groundwater levels to rainfall events attest further to the importance of preferential pathways in enabling rain-fed recharge via soil macro-pores. Our results suggest that, in these environments, increased use of groundwater to offset periods of low surface flow and to supplement soil moisture through irrigation may prove a logical strategy to enhance regional water and food security.

Taylor, R. G.; Owor, M.; Kaponda, A.

2013-12-01

382

A Seasonal Air Transport Climatology for Kenya  

NASA Technical Reports Server (NTRS)

A climatology of air transport to and from Kenya has been developed using kinematic trajectory modeling. Significant months for trajectory analysis have been determined from a classification of synoptic circulation fields. Five-point back and forward trajectory clusters to and from Kenya reveal that the transport corridors to Kenya are clearly bounded and well defined. Air reaching the country originates mainly from the Saharan region and northwestern Indian Ocean of the Arabian Sea in the northern hemisphere and from the Madagascan region of the Indian Ocean in the southern hemisphere. Transport from each of these source regions show distinctive annual cycles related to the northeasterly Asian monsoon and the southeasterly trade wind maximum over Kenya in May. The Saharan transport in the lower troposphere is at a maximum when the subtropical high over northern Africa is strongly developed in the boreal winter. Air reaching Kenya between 700 and 500 hPa is mainly from Sahara and northwest India Ocean flows in the months of January and March, which gives way to southwest Indian Ocean flow in May and November. In contrast, air reaching Kenya at 400 hPa is mainly from southwest Indian Ocean in January and March, which is replaced by Saharan transport in May and November. Transport of air from Kenya is invariant, both spatially and temporally, in the tropical easterlies to the Congo Basin and Atlantic Ocean in comparison to the transport to the country. Recirculation of air has also been observed, but on a limited and often local scale and not to the extent reported in southern Africa.

Gatebe, C. K.; Tyson, P. D.; Annegarn, H.; Piketh, S.; Helas, G.

1998-01-01

383

Phylogeography and population genetics of the maize stalk borer Busseola fusca (Lepidoptera, Noctuidae) in sub-Saharan Africa.  

PubMed

The population genetics and phylogeography of African phytophagous insects have received little attention. Some, such as the maize stalk borer Busseola fusca, display significant geographic differences in ecological preferences that may be congruent with patterns of molecular variation. To test this, we collected 307 individuals of this species from maize and cultivated sorghum at 52 localities in West, Central and East Africa during the growing season. For all collected individuals, we sequenced a fragment of the mitochondrial cytochrome b. We tested hypotheses concerning the history and demographic structure of this species. Phylogenetic analyses and nested clade phylogeographic analyses (NCPA) separated the populations into three mitochondrial clades, one from West Africa, and two--Kenya I and Kenya II--from East and Central Africa. The similar nucleotide divergence between clades and nucleotide diversity within clades suggest that they became isolated at about the same time in three different refuges in sub-Saharan Africa and have similar demographic histories. The results of mismatch distribution analyses were consistent with the demographic expansion of these clades. Analysis of molecular variance (amova) indicated a high level of geographic differentiation at different hierarchical levels. NCPA suggested that the observed distribution of haplotypes at several hierarchical levels within the three major clades is best accounted for by restricted gene flow with isolation by distance. The domestication of sorghum and the introduction of maize in Africa had no visible effect on the geographic patterns observed in the B. fusca mitochondrial genome. PMID:16448409

Sezonlin, M; Dupas, S; Le Rü, B; Le Gall, P; Moyal, P; Calatayud, P-A; Giffard, I; Faure, N; Silvain, J-F

2006-02-01

384

Population Vulnerability and Disability in Kenya's Tsetse Fly Habitats  

PubMed Central

Background Human African Trypanosomiasis (HAT), also referred to as sleeping sickness, and African Animal Trypanosomaisis (AAT), known as nagana, are highly prevalent parasitic vector-borne diseases in sub-Saharan Africa. Humans acquire trypanosomiasis following the bite of a tsetse fly infected with the protozoa Trypanosoma brucei (T.b.) spp. –i.e., T.b. gambiense in West and Central Africa and T.b. rhodesiense in East and Southern Africa. Over the last decade HAT diagnostic capacity to estimate HAT prevalence has improved in active case-finding areas but enhanced passive surveillance programs are still lacking in much of rural sub-Saharan Africa. Methodology/Principal Findings This retrospective-cross-sectional study examined the use of national census data (1999) to estimate population vulnerability and disability in Kenya's 7 tsetse belts to assess the potential of HAT-acquired infection in those areas. A multilevel study design estimated the likelihood of disability in individuals, nested within households, nested within tsetse fly habitats of varying levels of poverty. Residents and recent migrants of working age were studied. Tsetse fly's impact on disability was conceptualised via two exposure pathways: directly from the bite of a pathogenic tsetse fly resulting in HAT infection or indirectly, as the potential for AAT takes land out of agricultural production and diseased livestock leads to livestock morbidity and mortality, contributing to nutritional deficiencies and poverty. Tsetse belts that were significantly associated with increased disability prevalence were identified and the direct and indirect exposure pathways were evaluated. Conclusions/Significance Incorporating reports on disability from the national census is a promising surveillance tool that may enhance future HAT surveillance programs in sub-Saharan Africa. The combined burdens of HAT and AAT and the opportunity costs of agricultural production in AAT areas are likely contributors to disability within tsetse-infested areas. Future research will assess changes in the spatial relationships between high tsetse infestation and human disability following the release of the Kenya 2009 census at the local level.

Grady, Sue C.; Messina, Joseph P.; McCord, Paul F.

2011-01-01

385

Visualizing East Africa Drought and Vegetation Response in GIS using NASA Satellite Data  

NASA Astrophysics Data System (ADS)

NASA's Tropical Rainfall Measuring Mission (TRMM) provides extensive and timely estimation of precipitation at high spatial and temporal resolutions. The TRMM data products, ranging from near real-time to monthly average, are valuable in mapping and monitoring of drought events. Geographic information systems (GIS) has been widely used in drought related modeling and applications However, the TRMM data products have been under utilized by the GIS community, partly because most TRMM data are archived and distributed in generic binary and native Hierarchical Data Format (HDF), which are not directly addable to widely used GIS software packages. In this presentation, we'll show how the TRMM precipitation data can actually be readily imported into a GIS and be integrated with other types of spatial data, such as watershed and administrative boundaries, to map, visualize, and analyze drought events. We'll present, in a GIS environment, how the 2010-2011 East African drought, which caused significant decrease in crop production and left more than 10 million people in need for food assistance, is clearly captured by TRMM measurements; how the region's vegetation growing conditions, as depicted by NASA's normalized difference vegetation index data product which is archived in HDF-EOS format, respond to the drought; and how the drought and the vegetation response can be visualized and assessed at different watersheds in GIS.

Yang, W.; Zhao, P.; Chen, A.; Pham, L.; Kempler, S.

2012-12-01

386

Deltas of the Lake Malawi rift, east Africa: Seismic expression and exploration implications  

SciTech Connect

High-resolution, air-gun-sourced seismic reflection surveys over the offshore regions of five river deltas in Lake Malawi in the East African rift system reveal considerable variability in acoustic facies and stratigraphic architecture. This variability can largely be attributed to the influences of different structural settings, and to a lesser degree to high-amplitude (100-400 m) and high-frequency (1000 to 100,000 yr) fluctuations in lake level. Deltas on flexural and axial margins in the rift lake show well-developed progradational geometries. In contrast, a delta on a steep, accommodation zone margin distributes coarse sediments over a broad depositional apron, rather than concentrating sediment in discrete progradational lobes as on the other deltas. A large border fault margin river delta displays the most complex tectonic and stratigraphic architecture of all the deltas studied. It contains several delta-associated facies, including prograding clinoform packages, fan deltas stacked against a boundary fault, and extensive subaqueous fans. Flexural margin lowstand deltas may be the most prospective for hydrocarbon exploration due to their large, internally well-organized, progradational lobes and their close proximity to deep-water, high total organic carbon lacustrine source facies.

Scholz, C.A. [Univ. of Miami, FL (United States)

1995-11-01

387

Preliminary definition of geophysical regions for the Middle East and North Africa  

SciTech Connect

The ability to calibrate seismic stations to improve the monitoring of the Comprehensive Test Ban Treaty is partially limited by the availability of seismic events with known locations and source properties. To confidently extrapolate from these events to aseismic regions, and to properly account for discontinuities in seismic properties requires accurate geophysical models. This paper lays out a preliminary, first-order, regionalization of the Middle East and North African (MENA) region. The model specifies boundaries and velocity structures based on the geology and tectonics of the region, previously published studies, and empirical data observations by the LLNL group. This model is a starting point and is expected to be improved and refined by comparisons with ongoing tomography efforts and the collection of new data. We anticipate that this model and its successors will prove useful as a background model in the process of forming station calibration maps based on intelligent interpolation techniques such as kriging. We also hope the model, as it improves and demonstrates some predictive power, will provide a reference model for broader CTBT research efforts in detection, location and discrimination as well as other aspects of earth science.

Sweeney, J J; Walter, B

1998-12-01

388

A Predator from East Africa that Chooses Malaria Vectors as Preferred Prey  

PubMed Central

Background All vectors of human malaria, a disease responsible for more than one million deaths per year, are female mosquitoes from the genus Anopheles. Evarcha culicivora is an East African jumping spider (Salticidae) that feeds indirectly on vertebrate blood by selecting blood-carrying female mosquitoes as preferred prey. Methodology/Principal Findings By testing with motionless lures made from mounting dead insects in lifelike posture on cork discs, we show that E. culicivora selects Anopheles mosquitoes in preference to other mosquitoes and that this predator can identify Anopheles by static appearance alone. Tests using active (grooming) virtual mosquitoes rendered in 3-D animation show that Anopheles' characteristic resting posture is an important prey-choice cue for E. culicivora. Expression of the spider's preference for Anopheles varies with the spider's size, varies with its prior feeding condition and is independent of the spider gaining a blood meal. Conclusions/Significance This is the first experimental study to show that a predator of any type actively chooses Anopheles as preferred prey, suggesting that specialized predators having a role in the biological control of disease vectors is a realistic possibility.

Nelson, Ximena J.; Jackson, Robert R.

2006-01-01

389

Emergence, spread and strategies for controlling the pandemic of cassava mosaic virus disease in east and central Africa  

Microsoft Academic Search

During the 1990s, an epidemic of an unusually severe form of cassava mosaic virus disease (CMD) has expanded to cover virtually all of Uganda, and substantial areas in the neighbouring countries of Kenya, Tanzania, Sudan and the Democratic Republic of Congo. Losses in the generally sensitive local cassava cultivars have been so great that a common farmer response to the

J. P Legg

1999-01-01

390

Genetic differentiation of Anopheles gambiae populations from East and West Africa: comparison of microsatellite and allozyme loci  

Microsoft Academic Search

Genetic variation of Anopheles gambiae was analysed to assess interpopulation divergence over a 6000 km distance using short tandem repeat (microsatellite) loci and allozyme loci. Differentiation of populations from Kenya and Senegal measured by allele length variation at five microsatellite loci was compared with estimates calculated from published data on six allozyme loci (Miles, 1978). The average Wright's FST of

Tovi Lehmann; William A Hawley; Luna Kamau; Didier Fontenille; Frederic Simard; Frank H Collins

1996-01-01

391

The dominant Anopheles vectors of human malaria in Africa, Europe and the Middle East: occurrence data, distribution maps and bionomic pr?cis  

PubMed Central

Background This is the second in a series of three articles documenting the geographical distribution of 41 dominant vector species (DVS) of human malaria. The first paper addressed the DVS of the Americas and the third will consider those of the Asian Pacific Region. Here, the DVS of Africa, Europe and the Middle East are discussed. The continent of Africa experiences the bulk of the global malaria burden due in part to the presence of the An. gambiae complex. Anopheles gambiae is one of four DVS within the An. gambiae complex, the others being An. arabiensis and the coastal An. merus and An. melas. There are a further three, highly anthropophilic DVS in Africa, An. funestus, An. moucheti and An. nili. Conversely, across Europe and the Middle East, malaria transmission is low and frequently absent, despite the presence of six DVS. To help control malaria in Africa and the Middle East, or to identify the risk of its re-emergence in Europe, the contemporary distribution and bionomics of the relevant DVS are needed. Results A contemporary database of occurrence data, compiled from the formal literature and other relevant resources, resulted in the collation of information for seven DVS from 44 countries in Africa containing 4234 geo-referenced, independent sites. In Europe and the Middle East, six DVS were identified from 2784 geo-referenced sites across 49 countries. These occurrence data were combined with expert opinion ranges and a suite of environmental and climatic variables of relevance to anopheline ecology to produce predictive distribution maps using the Boosted Regression Tree (BRT) method. Conclusions The predicted geographic extent for the following DVS (or species/suspected species complex*) is provided for Africa: Anopheles (Cellia) arabiensis, An. (Cel.) funestus*, An. (Cel.) gambiae, An. (Cel.) melas, An. (Cel.) merus, An. (Cel.) moucheti and An. (Cel.) nili*, and in the European and Middle Eastern Region: An. (Anopheles) atroparvus, An. (Ano.) labranchiae, An. (Ano.) messeae, An. (Ano.) sacharovi, An. (Cel.) sergentii and An. (Cel.) superpictus*. These maps are presented alongside a bionomics summary for each species relevant to its control.

2010-01-01

392

The sup 36 Cl ages of the brines in the Magadi-Natron basin, east Africa  

SciTech Connect

The depression in the East African Rift which includes both Lake Magadi and Lake Natron forms a closed basin within which almost all the dissolved chloride originates in precipitation, since there is no important source of very ancient sedimentary chloride. This provides an ideal setting for the evaluation of the {sup 36}Cl methodology as a geochemical and hydrological tracer. The main source of recent water, as represented by the most dilute samples measured, is characterized by a {sup 36}Cl/Cl ratio of 2.5 {times} 10{sup {minus}14}, in agreement with the calculated value expected in precipitation. Surface evaporation increases the chlorinity of the local freshwater inflow by about a factor of 110 without changing the isotopic ratio, indicating that little chloride enters the system in the form of sediment leachate. A second type of brine found in the basin occurs in a hot deep groundwater reservoir and is characterized by lower {sup 36}Cl/Cl ratios (<1.2 {times} 10{sup {minus}14}). By comparing this value with the 2.5 {times} 10{sup {minus}14} in recent recharge, one obtains an approximate salt accumulation age of 760 Ka which is consistent with thee time of the first appearance of the lake. These older brines also have lower {sup 18}O and {sup 2}H values which indicate that they were recharged during a climatically different era. The {sup 36}Cl/Cl ratios in the inflowing waters and in the accumulated brine, together with the known age of the Lake Magadi basin, may be used to estimate the importance of the hypogene and epigene, as opposed to the meteoric, mode of {sup 36}Cl production. Such a calculation shows that the hypogene and epigene processes together contribute less than 6% of the total {sup 36}Cl present in the lake.

Kaufman, A.; Margaritz, M.A.; Hollos, G. (Weizmann Institute of Science, Rehovot (Israel)); Paul, M.; Boaretto, E. (Hebrew Univ., Jerusalem (Israel)); Hillaire-Marcel, C. (Universite du Quebec, Montreal (Canada)); Taieb, M. (Universite-Luminy, Marseille (France))

1990-10-01

393

Paleolimnology of Lake Tanganyika, East Africa, over the past 100 k yr  

USGS Publications Warehouse

New sediment core data from a unique slow-sedimentation rate site in Lake Tanganyika contain a much longer and continuous record of limnological response to climate change than have been previously observed in equatorial regions of central Africa. The new core site was first located through an extensive seismic reflection survey over the Kavala Island Ridge (KIR), a sedimented basement high that separates the Kigoma and Kalemie Basins in Lake Tanganyika. Proxy analyses of paleoclimate response carried out on core T97-52V include paleomagnetic and index properties, TOC and isotopic analyses of organic carbon, and diatom and biogenic silica analyses. A robust age model based on 11 radiocarbon (AMS) dates indicates a linear, continuous sedimentation rate nearly an order of magnitude slower here compared to other core sites around the lake. This age model indicates continuous sedimentation over the past 79 k yr, and a basal age in excess of 100 k yr. The results of the proxy analyses for the past ??? 20 k yr are comparable to previous studies focused on that interval in Lake Tanganyika, and show that the lake was about 350 m lower than present at the Last Glacial Maximum (LGM). Repetitive peaks in TOC and corresponding drops in ??13C over the past 79 k yr indicate periods of high productivity and mixing above the T97-52V core site, probably due to cooler and perhaps windier conditions. From ??? 80 through ??? 58 k yr the ??13C values are relatively negative (-26 to -28???) suggesting predominance of algal contributions to bottom sediments at this site during this time. Following this interval there is a shift to higher values of ??13C, indicating a possible shift to C-4 pathway-dominated grassland-type vegetation in the catchment, and indicating cooler, dryer conditions from ??? 55 k yr through the LGM. Two seismic sequence boundaries are observed at shallow stratigraphic levels in the seismic reflection data, and the upper boundary correlates to a major discontinuity near the base of T97-52V. We interpret these discontinuities to reflect major, prolonged drops in lake level below the core site (393 m), with the lower boundary correlating to marine oxygen isotope Stage 6. This suggests that the previous glacial period was considerably cooler and more arid in the equatorial tropics than was the last glacial period.

Scholz, C. A.; King, J. W.; Ellis, G. S.; Swart, P. K.; Stager, J. C.; Colman, S. M.

2003-01-01

394

Rural Development in Africa: A Bibliography. (Part I: General, Central, East). Training & Methods Series Number 16 (Supplement), March 1973.  

ERIC Educational Resources Information Center

A supplement to the bibliography of materials dealing with Africa in the Land Tenure Center Library at the University of Wisconsin, this bibliography on rural development in Africa is divided into three major sections as follows: (1) General (400 entries); (2) Central Africa including a general section (2 entries); Cameroon (26 entries); Central…

Anderson, Teresa, Comp.; Strey, Gerry, Comp.

395

New specimens of a fossil ostrich from the Miocene of Kenya  

NASA Astrophysics Data System (ADS)

Fossilised hind limb bones from the late Middle Miocene (approximately 14 million-year-old [MYA]) Fort Ternan, Kadianga West and Ngorora localities in Western Kenya indicate the presence of a new representative of the ostrich genus Struthio. These new fossils represent some of the oldest known records for Struthio yet described, slightly younger than Struthio coppensi, from the Lower Miocene of Namibia. Because the four sub-species of the modern-day ostrich ( Struthio camelus camelus, Struthio camelus australis, Struthio camelus massaicus, and Struthio camelus molybdophanes) inhabit the plains of Africa, and as recently as the 1940s, a fifth sub-species was also present in the Middle East and Saudi Arabia ( Struthio camelus syriacus), records of Struthio from Kenya and Namibia testify to the much wider distribution of these cursorial birds in the relatively recent past. This is further supported by the very high frequency of ostrich eggshell fragments found across Africa and Eurasia, which vastly outweighs the amount of skeletal material uncovered over the last century.

Leonard, Leona M.; Dyke, Gareth J.; Walker, Cyril A.

2006-08-01

396

Anisotropic complexity in Tanzania and Kenya from teleseismic shear-wave splitting  

NASA Astrophysics Data System (ADS)

Previous studies have found that shear-wave splitting fast directions in western Kenya are roughly parallel to the Kenya Rift, part of the East Africa rift system. This anisotropy can be explained by three different mechanisms: fossilized anisotropy in the lithosphere from previous orogenic events, vertically oriented magma-filled lenses in the lithosphere and asthenosphere, and asthenospheric flow along the base of the plate that is guided by a background asthenospheric flow current and/or channeled by upwarped basal lithospheric topography beneath the rift. Preliminary results from Ethiopia appear to be similar to those in Kenya (M. Kendall, pers. commun., 2003). Resolving between these mechanisms has major implications on the evolution of rifting, the geodynamics associated with rift/hotspot interactions, and the origin of anisotropy detected by shear-wave splitting. Tanzania and Kenya comprise a unique, tectonically complex region due to the presence of a rigid craton, paleo-thrust belts and shear zones, active magmatism and rifting, and possibly even a nearby mantle plume. We present new results of teleseismic splitting analysis of SKS, SKKS, PKS, and S recorded by 20 broadband seismic stations in Tanzania, 7 broadband stations in Kenya, and 3 permanent broadband GSN stations in Kenya and Uganda. Fast directions (phi) from most of the craton stations are oriented WNW and are subparallel to both absolute plate motion and the strike of the well-defined surficial fold axes. The delay times (dt) are ˜0.5 s, and when combined with previously published surface-wave results, suggest anisotropy in the lower lithosphere and asthenosphere beneath the craton, which would be expected due to relative motion between the WNW moving plate and a fixed underlying mantle. However, the fast direction/structural fabric correlation at the surface, and the lack of WNW plate-motion parallel fast directions in the Kaapvaal craton in southern Africa suggests that vertically coherent deformation best explains craton splitting. In the mobile belts and rifts, phi is roughly parallel to the strike of the rifts, the paleo-shortening directions, and the edge of the craton, with significant variations between stations. For most of these stations, dt ranges from ˜0.8-1.5 s, and suggests that at least a significant part of the anisotropy is in the asthenosphere. We interpret the dominant off-craton mantle anisotropy in Kenya and Tanzania to be due to shear along the base of the plate associated with plume flow around the craton keel. Significant variations between nearby stations are assumed to be due to the secondary effects of fossilized anisotropy or anisotropy due to magma-filled lenses or partially molten dikes in the lithosphere/asthenosphere. Our data strongly suggest that extension has not led to the development of a resolvable LPO in the lithospheric mantle, which is surprising given the long history of extension in the region. This suggests that mantle-lithosphere extension in East Africa occurs within narrow rift zones via ductile thinning and/or dike intrusion, possibly facilitated by mechanical lithospheric anisotropy from fossilized N-S fabrics that originated from prior orogenic events.

Walker, K. T.; Nyblade, A. A.; Bokelmann, G. H.; Klemperer, S. L.; Owens, T. J.

2003-12-01

397

Greening of the Sahara - a paleo perspective on the history of water in the Middle East and North Africa  

NASA Astrophysics Data System (ADS)

The Middle-East, mostly at its southern edge together with North Africa, the northern edge of the Sahara Desert, are located at the boundary between high- to-mid latitude and tropical-subtropical climate systems. The geographical duality of desert adjacent to Mediterranean-type climate regions played and still plays a major role on the water availability. Thanks to the number of important paleoclimate studies that been made on accurate dating of cave speleothems in Southern Arabia and Oman (Fleitmann et al., 2011) and in the northeast Sahara, the Negev Desert Israel (Vaks et al., 2010) and the study of sapropels in Eastern and central Mediterranean (Almogi-Labin et al., 2009; Osborne et al, 2008), it is clear that the region was graced with water during peak interglacials when the African monsoon and westerly storm/rainfall systems intensified. Northward penetration of the Inter Tropical Convergence Zone over the Arabian and African continents resulted in increased discharge of the Nile River and rivers that emerged from central Sahara into the Eastern Mediterranean Sea. Correspondingly, enhanced westerly wind activity led to an increase in rainfall from Atlantic-Mediterranean sources over the entire Mediterranean basin, which even penetrated south into the north-east corner of the Sahara Desert. The Saharo-Arabian Desert became narrower and climatic "windows" opened for the dispersal of hominids and animals out of the African continent at 250-239, 210-193, 138-120, 108-98, 87-84 and 10-6.5 ka BP, with severe dry conditions in between. Greening of the Sahara Desert at these intervals is supported also by various marine and terrestrial records, such as corals, lakes, tufa deposits and archeological findings. Dry conditions prevailed in the Sahara desert during glacials. This is in contrast to the climatic conditions in the Eastern Mediterranean coastal region and the Jordan Rift Valley (Bar-Matthews et al., 2003; Lisker et al., 2010), where water was available for humans and animals who enjoyed a variety of ecological niches for living (Frumkin et al., 2011). Almogi-Labin, A. et a.l (2009) Quat. Sci. Rev. 28, 2882-2896. Bar-Matthews, M. et al (2003 Geochim. Cosmochim. Acta 67, 3181-99. Fleitmann, D. et al. (2011). Quat. Sci. Rev. 30, 783-787. Frumkin, et al. A. (2011). Jour. Human Evol. 60, 437-451 Lisker et al, (2010). Quat. Sci. Rev 29, 1201-1211. Osborne A.H. et al. (2008). Proc. Nat. Acad. Sci. 105, 16444-16447 Vaks et al. (2010). Quat. Sci. Rev. 29, 2647-2662.

Bar-Matthews, M.

2012-04-01

398

Cenozoic vegetation, climate changes and hominid evolution in tropical Africa  

NASA Astrophysics Data System (ADS)

This paper reviews information on past vegetation of tropical Africa during the Cenozoic, focused upon the last 10 Ma, a time spanning hominid record in Central and East Africa. Summary of palaeobotanical data collected at terrestrial sites are compared with new results on the long term evolution of the continental vegetation zones documented from marine pollen record of two deep sea cores recovered from the Atlantic and Indian Oceans. Section 2 includes a summary of modern distribution of vegetation belts in the African continent and a synthesis of the results of both macrobotanical (fossil wood, leaves and fruits) and microbotanical (mainly pollen) studies presented according to time scale and geographical location. The main features emphasized by the palaeobotanical results are 1) seasonal vegetation and climate documented as soon as the Eocene in Tanzania 2) well diversified forests existing in northern West Ethiopia during the Oligocene 3) high temporal and spatial variabilities of forests composition during the Miocene when deciduous Legume woodland was documented in Ethiopia whereas wetter evergreen forests existed in Western Kenya 4) lack of evidence for an evergreen forest belt, continuous from Western Congo to East Africa. Section 3 presents new original pollen data recovered from a long core in the Gulf of Aden documenting large scale past vegetation changes in East Africa during the last 11 Ma. These results are discussed in comparison with a summarized long pollen sequence previously published from a marine core offshore the Niger delta. This comparison illustrates variations in geographical distribution of large vegetation zone at the continental scale, through time. In Section 4, vegetation changes registered during the last 10 Ma are discussed in relation with the results of isotopic studies and an updated presentation of hominids evolution in Africa. Several changes are shown in the marine records. An expansion of savanna/grassland is shown at 10 Ma in East Africa, 3 Ma earlier than in West Africa where it is documented at 7 Ma. At large geographical scale, this first increase in grass pollen simultaneously to forest increase in the marine records is interpreting as reflecting wetter conditions over the continent. Indeed, under global humid conditions, savanna could spread over the desert areas in the Northern and Eastern directions. A forest phase is well documented in West Africa between 7.5 and 7 Ma, but has not been shown in East Africa, mainly because of low resolution analysis of the DSDP East African record which needs further investigation for that period. A strong vegetation change took place between 6.3 and 6 Ma. It was marked by a trend of important decrease tree cover of the vegetation, simultaneous in West and East Africa. At that time, very arid conditions shown by scarce tree cover occurred over the whole tropical region. This happened before (or at) the early beginning of the Messinian crisis. Generally arid conditions coincide with the accepted timing for the Chimpanzee/hominid split, and record of Sahelanthropus tchadensis in Chad and Orrorin tugenensis in Kenya, although these fossils were found under locally wooded environment. The period from 6 to 4 Ma saw the appearance of Ardipithecus and diversification of Australopithecines occurring during a progressive increased tree cover in the broad-scale vegetation that culminated at 3.9 Ma, during A. anamensis time and before the first appearance of Australopithecus afarensis. Important variations in the vegetation occurred between 4 and 3 Ma, and many plant ecosystems were available to A.afarensis, a hominid which had a wide geographical distribution and persisted at Hadar under temporal climatic and environmental variability. The strongest and abrupt decline of forest pollen accompanied by an increase in the grass pollen was found at 2.7 Ma, more pronounced in the West than in East Africa. It was accompanied by a significant increase in C 4 grass proportions, well indicated in the Turkana region and likely explained by an increase in dry

Bonnefille, Raymonde

2010-07-01

399

Neglected Tropical Diseases of the Middle East and North Africa: Review of Their Prevalence, Distribution, and Opportunities for Control  

PubMed Central

The neglected tropical diseases (NTDs) are highly endemic but patchily distributed among the 20 countries and almost 400 million people of the Middle East and North Africa (MENA) region, and disproportionately affect an estimated 65 million people living on less than US$2 per day. Egypt has the largest number of people living in poverty of any MENA nation, while Yemen has the highest prevalence of people living in poverty. These two nations stand out for having suffered the highest rates of many NTDs, including the soil-transmitted nematode infections, filarial infections, schistosomiasis, fascioliasis, leprosy, and trachoma, although they should be recognized for recent measures aimed at NTD control. Leishmaniasis, especially cutaneous leishmaniasis, is endemic in Syria, Iran, Iraq, Libya, Morocco, and elsewhere in the region. Both zoonotic (Leishmania major) and anthroponotic (Leishmania tropica) forms are endemic in MENA in rural arid regions and urban regions, respectively. Other endemic zoonotic NTDs include cystic echinococcosis, fascioliasis, and brucellosis. Dengue is endemic in Saudi Arabia, where Rift Valley fever and Alkhurma hemorrhagic fever have also emerged. Great strides have been made towards elimination of several endemic NTDs, including lymphatic filariasis in Egypt and Yemen; schistosomiasis in Iran, Morocco, and Oman; and trachoma in Morocco, Algeria, Iran, Libya, Oman, Saudi Arabia, Tunisia, and the United Arab Emirates. A particularly noteworthy achievement is the long battle waged against schistosomiasis in Egypt, where prevalence has been brought down by regular praziquantel treatment. Conflict and human and animal migrations are key social determinants in preventing the control or elimination of NTDs in the MENA, while local political will, strengthened international and intersectoral cooperative efforts for surveillance, mass drug administration, and vaccination are essential for elimination.

Hotez, Peter J.; Savioli, Lorenzo; Fenwick, Alan

2012-01-01

400

A molecular perspective on Late Quaternary climate and vegetation change in the Lake Tanganyika basin, East Africa  

NASA Astrophysics Data System (ADS)

Characterizing the nature of past hydrological change and its interactions with vegetation is fundamental to acquiring a better understanding of continental tropical climate dynamics. Here, we outline major shifts in the climate and ecosystem of tropical East Africa for the past 60,000 years (60 ka) by examining molecular records of hydrology, vegetation, and temperature from a sediment sequence from Lake Tanganyika. We demonstrate, via comparison with pollen spectra, that stable carbon isotopes measured on higher plant leaf waxes ( ?13C wax) are a reliable proxy for vegetation change. In addition we argue that the D/H ratio of higher plant leaf waxes ( ?D wax) is a robust and independent indicator of past changes in aridity, and is not affected by regional vegetation change directly. Our paired, compound-specific isotope data show that shifts in vegetation lead major changes in hydrology in the Tanganyika basin at several major climate transitions during the past 60,000 years, suggesting that vegetation in the Tanganyika basin is not as sensitive to aridity as previous studies have suggested and that variations in carbon dioxide, temperature, and internal ecosystem dynamics are equally, if not more, important. We hypothesize that regional vegetation change may exert a positive feedback on regional hydrology, thus partially accounting for the abrupt threshold behavior evident in our paleohydrological data. Furthermore, we find that past changes in Tanganyika basin climate and ecology are closely linked to concentrations of atmospheric trace gases, highlighting the paramount influence of global climatic shifts upon regional tropical climate over gla